JPH06295129A - Magnetic toner and developing device - Google Patents

Abstract

(57) [Summary] [Objective] The magnetic strength of the magnetic toner is reduced without reducing the amount of magnetic material in the magnetic toner, and the process of imparting charge to the magnetic toner is stabilized, improving image reproducibility. Providing magnetic toner and developing device. [Structure] A magnetic toner containing at least a magnetic material,
A developing device having a developer carrying member carrying on its surface a developer containing the magnetic toner, a restricting member for restricting application of the developer on the developer carrying member, and a magnet inside the developer carrying member. In the magnetic toner, the magnetic toner contains a magnetic material made of a metal oxide having a magnetization intensity of 10 to 40 emu / g in a magnetic field of 1 KOe (Oersted) and a horizontal ferret diameter of 0.05 to 0.5 μm. A characteristic magnetic toner, and in the developing device, the developer carrying member is provided at a position in the vicinity of the developer carrying body on the downstream side in the developer carrying direction on the developer carrying body with respect to the developer carrying member. A developing device having a means for changing a binding state between the magnetic toners on the body, and a magnetic toner used in the device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic toner used in an electrophotographic apparatus and a developing apparatus.

[0002]

[Prior art]

(First Invention) Conventionally, as a dry developing method of electrophotography, a method of using a magnetic one-component toner as a developer and a method of using two components of a carrier and a toner are generally widely used. The two developing methods using the above-mentioned developer have the following advantages, that is, the one-component developing method can reduce the size of the developing device structure, and the two-component developing method can sufficiently impart the electric charge to the toner. Therefore, it has an advantage that the design allowable range is wide.

However, as can be seen from the fact that the above advantages are in the direction of compensating for the disadvantages of the respective systems, the one component system has a narrow design allowable range of the toner and the developing system because the process of imparting charge to the toner is not sufficient. The two-component method has a disadvantage that the apparatus configuration becomes complicated because the mixed concentration of toner and carrier must be controlled to a constant value.

Further, in the copy image by each system, the magnetic one-component system has a chained toner (generally,
It is developed while becoming a "ear"),
The resolution in the horizontal direction of the image tends to be worse than that in the vertical direction, for example, there is a tendency of tailing, and there is a tendency of being less sharp than that of the two-component method. There is a tendency to say that traces are likely to appear.

(Second Invention) Conventionally, as a dry developing method of electrophotography, a method of using a magnetic one-component toner as a developer and a method of using two components of a carrier and a toner are generally well used. Two developing methods using the above developer are
Each has the following advantages, that is, the one-component developing method can reduce the size of the developing device structure, and the two-component developing method has an advantage that the design allowable range is wide because the charge can be sufficiently applied to the toner. is doing.

However, as can be seen from the fact that the above-mentioned advantages are in the direction of compensating for the disadvantages of the respective systems, the one-component system has a narrow design allowable range of the toner and the developing system because the process of imparting charge to the toner is not sufficient. The two-component method has a disadvantage that the apparatus configuration becomes complicated because the mixed concentration of toner and carrier must be controlled to a constant value.

Further, in the copied image by each method, the magnetic one-component method has a chain-like toner (generally, toner at the time of development).
It is developed while becoming a "ear"),
The resolution in the horizontal direction of the image tends to be worse than that in the vertical direction, for example, there is a tendency of tailing, and there is a tendency of being less sharp than that of the two-component method. There is a tendency to say that traces are likely to appear.

(Third invention) Conventionally, as a dry developing method of electrophotography, a method of using a magnetic one-component toner as a developer and a method of using two components of a carrier and a toner are generally well used. Two developing methods using the above developer are
Each has the following advantages, that is, the one-component developing method can reduce the size of the developing device structure, and the two-component developing method has an advantage that the design allowable range is wide because the charge can be sufficiently applied to the toner. is doing.

However, as can be seen from the fact that the above advantages are in the direction of compensating for the disadvantages of the respective systems, the one-component system has a narrow design allowable range of the toner and the developing system because the process of imparting charge to the toner is not sufficient. The two-component method has a disadvantage that the apparatus configuration becomes complicated because the mixed concentration of toner and carrier must be controlled to a constant value.

Further, in the copied image by each method, the magnetic one-component method has a chain-like toner (generally, toner at the time of development).
It is developed while becoming a "ear"),
The resolution in the horizontal direction of the image tends to be worse than that in the vertical direction, for example, there is a tendency of tailing, and there is a tendency of being less sharp than that of the two-component method. There is a tendency to say that traces are likely to appear.

(Fourth Invention) Conventionally, as a dry developing method of electrophotography, a method of using a magnetic one-component toner as a developer and a method of using two components of a carrier and a toner are generally well used. Two developing methods using the above developer are
Each has the following advantages, that is, the one-component developing method can reduce the size of the developing device structure, and the two-component developing method has an advantage that the design allowable range is wide because the charge can be sufficiently applied to the toner. is doing.

However, as can be seen from the fact that the above-mentioned advantages are in the direction of compensating for the disadvantages of the respective systems, the one-component system has a narrow design allowable range of the toner and the developing system because the process of imparting charge to the toner is not sufficient. The two-component method has a disadvantage that the apparatus configuration becomes complicated because the mixed concentration of toner and carrier must be controlled to a constant value.

Further, in the copied image by each system, the magnetic one-component system is such that the toner is chained (generally,
It is developed while becoming a "ear"),
The resolution in the horizontal direction of the image tends to be worse than that in the vertical direction, for example, there is a tendency of tailing, and there is a tendency of being less sharp than that of the two-component method. There is a tendency to say that traces are likely to appear.

(Fifth Invention) Conventionally, as a dry developing method of electrophotography, a method of using a magnetic one-component toner as a developer and a method of using two components of a carrier and a toner are generally widely used. Two developing methods using the above developer are
Each has the following advantages, that is, the one-component developing method can reduce the size of the developing device structure, and the two-component developing method has an advantage that the design allowable range is wide because the charge can be sufficiently applied to the toner. is doing. However, as the advantages described above tend to compensate for the disadvantages of both methods,
The component system has a narrow design allowable range of the toner and the developing system because the process of imparting electric charge to the toner is not sufficient, and the two-component system has to control the mixed concentration of the toner and the carrier to a constant value, and therefore the device configuration is It has the disadvantage of complexity.

Further, in the copied image by each system, the magnetic one-component system has toner in a chain shape (generally, at the time of development).
It is developed while becoming a "ear"),
The resolution in the horizontal direction of the image tends to be worse than that in the vertical direction, for example, there is a tendency of tailing, and there is a tendency of being less sharp than that of the two-component method. There is a tendency to say that traces are likely to appear.

(Sixth Invention) Conventionally, as a dry developing method of electrophotography, a method of using a magnetic one-component toner as a developer and a method of using two components of a carrier and a toner are generally well used. Two developing methods using the above developer are
Each has the following advantages, that is, the one-component developing method can reduce the size of the developing device structure, and the two-component developing method has an advantage that the design allowable range is wide because the charge can be sufficiently applied to the toner. is doing.

However, as can be seen from the fact that the above-mentioned advantages are in the direction of compensating for the disadvantages of the respective systems, the one-component system has a narrow design allowable range of the toner and the developing system because the process of imparting charge to the toner is not sufficient. The two-component method has a disadvantage that the apparatus configuration becomes complicated because the mixed concentration of toner and carrier must be controlled to a constant value.

Further, in the copied image by each method, the magnetic one-component method has a chain toner (generally, toner at the time of development).
It is developed while becoming a "ear"),
The resolution in the horizontal direction of the image tends to be worse than that in the vertical direction, for example, there is a tendency of tailing, and there is a tendency of being less sharp than that of the two-component method. There is a tendency to say that traces are likely to appear.

[0019]

[Problems to be Solved by the Invention]

(First Invention) As described above, one of the disadvantages of the magnetic one-component system is that the charge application process is insufficient, and the other is that the toner contains a magnetic substance. Two points are poor image reproducibility.

As a method of solving the image reproducibility, it is conceivable to make the ears of the toner short and dense, and as a means therefor, it is easy to imagine a method of reducing the ratio of the amount of magnetic material in the toner. Yes, but in general, current development systems rely on the absolute value of the specific charge of the toner,
It is difficult to develop a toner containing a reduced amount of magnetic material for the following reasons.

That is, if the radius of one toner is R, the charge amount is Q, and the density is ρ, the specific charge Q / M of the toner can be expressed as Q / M = 3Q / 4πρR ³ . The density of the magnetic substance in the toner of a general magnetic one-component toner is several times higher than the density of the binder resin. Therefore, the toner density ρ decreases as the amount of magnetic material in the toner decreases, and the specific charge increases conversely. As is well known, an increase in specific charge tends to cause a low image density. In particular, as is clear from the above equation, the tendency becomes more remarkable as the toner particle size is reduced.

Further, the image quality of a copied image in the magnetic one-component developing system is greatly influenced by the cohesiveness of the toner. As is well known, when the amount of the magnetic substance contained in the magnetic toner is reduced, the magnetic toner easily aggregates in the developing device. It is considered that this is because the magnetic repulsive force due to the magnetic characteristics of the magnetic toner is relatively weakened against the powder cohesive force between the magnetic toner particles.

That is, when the strength of magnetization of the toner is large, a strong attractive force along the magnetic field direction and a strong repulsive force in the direction perpendicular to the magnetic field are generated between the toner particles. Therefore, the ears formed by the toner become long and coarse, and one ears become thin, and conversely, when the magnetization of the toner is small, the ears become short and dense, and Since the bond between the toners cannot be released, one ear becomes thick and short, and becomes an agglomerated state.

In the latter case, that is, when the ears become thick, the toner inside the ears becomes insufficiently charged. Therefore, simply reduce the ratio of the amount of magnetic material in the toner,
There is a problem in that when trying to shorten the ears, deterioration of image quality such as fogging due to poor charging of toner is likely to occur. Further, in general, the magnetic material also serves as a coloring material, so if the amount of the magnetic material is reduced as it is, it is easily considered that the image density becomes insufficient.

Therefore, as described above, the magnetic toner which reduces the magnetic strength of the magnetic toner without reducing the amount of the magnetic material in the magnetic toner, and improves the charging imparting stability and the image reproducibility, and the development thereof. There wasn't enough equipment yet.

(Second invention) As described above, the magnetic 1
The two disadvantages of the component system are that the charge application process is insufficient and that the image reproducibility is poor because the toner contains a magnetic material.

As a method of solving the image reproducibility, it is conceivable to make the ears of the toner short and dense, and as a means therefor, it is easy to imagine a method of reducing the ratio of the amount of magnetic material in the toner. Yes, but in general, current development systems rely on the absolute value of the specific charge of the toner,
It is difficult to develop a toner containing a reduced amount of magnetic material for the following reasons.

That is, if the radius of one toner is R, the amount of charge is Q, and the density is ρ, the specific charge Q / M of the toner can be expressed as Q / M = 3Q / 4πρR ³ . The density of the magnetic substance in the toner of a general magnetic one-component toner is several times higher than the density of the binder resin. Therefore, the toner density ρ decreases as the amount of magnetic material in the toner decreases, and the specific charge increases conversely. As is well known, an increase in specific charge tends to cause a low image density. In particular, as is clear from the above equation, the tendency becomes more remarkable as the toner particle size is reduced.
Further, the image quality of a copied image in the magnetic one-component developing system is greatly influenced by the cohesiveness of the toner.

As is well known, when the amount of the magnetic material contained in the magnetic toner is reduced, the magnetic toner easily aggregates in the developing device. It is considered that this is because the magnetic repulsive force due to the magnetic characteristics of the magnetic toner is relatively weakened against the powder cohesive force between the magnetic toner particles. That is, when the strength of magnetization of the toner is large, a strong attractive force along the magnetic field direction and a strong repulsive force in the direction perpendicular to the magnetic field are generated between the toner particles.

Therefore, the ears formed by the toner are
Long and coarse, and one ear becomes thin, and conversely, if the strength of magnetization of the toner is small, this time the ear becomes short and dense, and the bond between the toners cannot be released. One ear becomes thick and short, and becomes aggregated. In the latter case, ie
When the ears become thick, the toner inside the ears becomes insufficiently charged. Therefore, if you try to shorten the spikes simply by decreasing the ratio of the amount of magnetic material in the toner,
There is a problem that the deterioration of image quality such as fogging due to poor charging of toner is likely to occur.

Further, in general, the magnetic substance also functions as a coloring material, and therefore it is easily conceivable that the image density becomes insufficient if the amount of the magnetic substance is reduced as it is. Therefore,
As described above, it is still sufficient for the magnetic toner and its developing device to reduce the magnetization intensity of the magnetic toner without reducing the amount of the magnetic substance in the magnetic toner, and improve the charging stability and the image reproducibility. There was no such thing.

In order to solve the above problems, the present inventor has
A magnetic toner containing a magnetic material, a developer carrying member carrying on its surface a developer containing the magnetic toner, a magnet disposed inside the developer carrying member, and a developer on the developer carrying member. In a developing device having a regulating member for regulating the application of
By adjusting the strength of magnetization of the magnetic material contained in the magnetic toner in the magnetic field of 1 KOe and the content of the magnetic material in the magnetic toner, and in the developing device, the developer near the developer carrying member By disposing at least one or more counter electrodes for the carrier and applying an alternating electric field between the counter electrodes and the developer carrier, at least one or more of the counter electrodes is provided for the developer regulating member. By arranging the counter electrode on the downstream side in the developer carrying direction on the developer carrier, the strength of magnetization of the magnetic toner can be reduced without reducing the amount of magnetic material in the magnetic toner. In addition, a magnetic toner and a developing device have been proposed which stabilize the process of applying a charge to the magnetic toner.

By using the configuration proposed above, it is possible to reduce the magnetic strength of the magnetic toner without reducing the amount of magnetic material in the magnetic toner, and improve the stability of charging and the image reproducibility. However, in the above structure, when the time for the number of vibrations of the developer due to the alternating electric field cannot be sufficiently taken with respect to the time for the developer to pass between the counter electrode and the developer regulating member, In some cases, the charge was not sufficiently applied to the toner. Further, in order to solve the above problem, when the applied electric field is changed, the applied voltage may leak and the developed image may be disturbed under high humidity depending on the magnetic toner.

(Third invention) As described above, the magnetic 1
The two disadvantages of the component system are that the charge application process is insufficient and that the image reproducibility is poor because the toner contains a magnetic material.

As a method of solving the image reproducibility, it is conceivable to make the ears of the toner short and dense, and as a means therefor, it is easy to imagine a method of reducing the ratio of the amount of magnetic material in the toner. Yes, but in general, current development systems rely on the absolute value of the specific charge of the toner,
It is difficult to develop a toner containing a reduced amount of magnetic material for the following reasons.

That is, if the radius of one toner is R, the charge amount is Q, and the density is ρ, the specific charge Q / M of the toner can be expressed as Q / M = 3Q / 4πρR ³ . The density of the magnetic substance in the toner of a general magnetic one-component toner is several times higher than the density of the binder resin. Therefore, the toner density ρ decreases as the amount of magnetic material in the toner decreases, and the specific charge increases conversely. As is well known, an increase in specific charge tends to cause a low image density. In particular, as is clear from the above equation, the tendency becomes more remarkable as the toner particle size is reduced.

Further, the image quality of a copied image in the magnetic one-component developing system is greatly influenced by the cohesiveness of the toner. As is well known, when the amount of the magnetic substance contained in the magnetic toner is reduced, the magnetic toner easily aggregates in the developing device. It is considered that this is because the magnetic repulsive force due to the magnetic characteristics of the magnetic toner is relatively weakened against the powder cohesive force between the magnetic toner particles. That is, when the strength of magnetization of the toner is large, a strong attractive force along the magnetic field direction and a strong repulsive force in the direction perpendicular to the magnetic field are generated between the toner particles.

Therefore, the ears formed by the toner are
Long and coarse, and one ear becomes thin, and conversely, if the strength of magnetization of the toner is small, this time the ear becomes short and dense, and the bond between the toners cannot be released. One ear becomes thick and short, and becomes aggregated.

In the latter case, that is, when the ears become thick, the toner inside the ears becomes insufficiently charged. Therefore, simply reduce the ratio of the amount of magnetic material in the toner,
There is a problem in that when trying to shorten the ears, deterioration of image quality such as fogging due to poor charging of toner is likely to occur.

Further, in general, the magnetic material also serves as a coloring material, and therefore it is easily conceivable that the image density becomes insufficient if the amount of the magnetic material is reduced as it is. Therefore,
As described above, it is still sufficient for the magnetic toner and its developing device to reduce the magnetization intensity of the magnetic toner without reducing the amount of the magnetic substance in the magnetic toner, and improve the charging stability and the image reproducibility. There was no such thing.

In order to solve the above problems, the present inventor has
A magnetic toner containing a magnetic material, a developer carrying member carrying on its surface a developer containing the magnetic toner, a magnet disposed inside the developer carrying member, and a developer on the developer carrying member. In a developing device having a regulating member for regulating the application of
By adjusting the strength of magnetization of the magnetic material contained in the magnetic toner in the magnetic field of 1 KOe and the content of the magnetic material in the magnetic toner, and in the developing device, the developer near the developer carrying member By disposing at least one counter electrode for the carrier and applying an alternating electric field between the counter electrode and the developer carrier,

At least 1 is added to the developer regulating member.
By arranging at least one of the counter electrodes on the downstream side of the developer carrying member in the developer transport direction, the magnetization of the magnetic toner can be suppressed without reducing the amount of the magnetic substance in the magnetic toner. A magnetic toner and a developing device that reduce the strength and stabilize the charge application process to the magnetic toner have been proposed.

By using the configuration proposed above, it is possible to reduce the strength of magnetization of the magnetic toner without reducing the amount of the magnetic material in the magnetic toner, and improve the stability of charging and the image reproducibility. However, in the above configuration, since an alternating electric field is applied between the counter electrode and the developer regulating member, it depends on the magnetic toner or the voltage of the alternating electric field, but under high humidity,
There is a problem that the applied electric field may leak and disturb the developed image.

(Fourth Invention) As described above, the magnetic 1
The two disadvantages of the component system are that the charge application process is insufficient and that the image reproducibility is poor because the toner contains a magnetic material.

As a method for solving the image reproducibility, it is conceivable to make the ears of the toner short and dense, and as a means therefor, it is easy to imagine a method of reducing the ratio of the magnetic substance amount in the toner. Yes, but in general, current development systems rely on the absolute value of the specific charge of the toner,
It is difficult to develop a toner containing a reduced amount of magnetic material for the following reasons.

That is, if the radius of one toner is R, the charge amount is Q, and the density is ρ, the specific charge Q / M of the toner can be expressed as Q / M = 3Q / 4πρR ³ . The density of the magnetic substance in the toner of a general magnetic one-component toner is several times higher than the density of the binder resin. Therefore, the toner density ρ decreases as the amount of magnetic material in the toner decreases, and the specific charge increases conversely. As is well known, an increase in specific charge tends to cause a low image density. In particular, as is clear from the above equation, the tendency becomes more remarkable as the toner particle size is reduced.

Further, the image quality of a copied image in the magnetic one-component developing system is greatly influenced by the cohesiveness of the toner. As is well known, when the amount of the magnetic substance contained in the magnetic toner is reduced, the magnetic toner easily aggregates in the developing device. It is considered that this is because the magnetic repulsive force due to the magnetic characteristics of the magnetic toner is relatively weakened against the powder cohesive force between the magnetic toner particles. That is, when the strength of magnetization of the toner is large, a strong attractive force along the magnetic field direction and a strong repulsive force in the direction perpendicular to the magnetic field are generated between the toner particles.

Therefore, the ears formed by the toner are
Long and coarse, and one ear becomes thin, and conversely, if the strength of magnetization of the toner is small, this time the ear becomes short and dense, and the bond between the toners cannot be released. One ear becomes thick and short, and becomes aggregated.

In the latter case, that is, when the ears become thick, the toner inside the ears becomes insufficiently charged. Therefore, simply reduce the ratio of the amount of magnetic material in the toner,
There is a problem in that when trying to shorten the ears, deterioration of image quality such as fogging due to poor charging of toner is likely to occur. Further, in general, the magnetic material also serves as a coloring material, so if the amount of the magnetic material is reduced as it is, it is easily considered that the image density becomes insufficient. Therefore, as described above, a magnetic toner and a developing device for the magnetic toner that can reduce the strength of magnetization of the magnetic toner without reducing the amount of the magnetic material in the magnetic toner and improve the charging imparting stability and the image reproducibility. Wasn't enough yet.

(Fifth Invention) As described above, the magnetic 1
The two disadvantages of the component system are that the charge application process is insufficient and that the image reproducibility is poor because the toner contains a magnetic material. As a method of solving the image reproducibility, it is conceivable to make the ears of the toner short and dense, and as a means therefor, a method of reducing the ratio of the amount of magnetic material in the toner can be easily imagined. Generally, since the current developing system depends on the absolute value of the specific charge of the toner, it is difficult to develop the toner containing the reduced amount of the magnetic substance for the following reasons.

That is, if the radius of one toner is R, the charge amount is Q, and the density is ρ, the specific charge Q / M of the toner can be expressed as Q / M = 3Q / 4πρR ³ . The density of the magnetic substance in the toner of a general magnetic one-component toner is several times higher than the density of the binder resin. Therefore, the toner density ρ decreases as the amount of magnetic material in the toner decreases, and the specific charge increases conversely. As is well known, an increase in specific charge tends to cause a low image density. In particular, as is clear from the above equation, the tendency becomes more remarkable as the toner particle size is reduced.

Further, the image quality of a copied image in the magnetic one-component developing system is greatly influenced by the cohesiveness of the toner. As is well known, when the amount of the magnetic substance contained in the magnetic toner is reduced, the magnetic toner easily aggregates in the developing device. It is considered that this is because the magnetic repulsive force due to the magnetic characteristics of the magnetic toner is relatively weakened against the powder cohesive force between the magnetic toner particles.

That is, when the strength of the magnetization of the toner is large, a strong attractive force along the magnetic field direction and a strong repulsive force in the direction perpendicular to the magnetic field are generated between the toner particles. Therefore, the ears formed by the toner become long and coarse, and one ears become thin, and conversely, when the magnetization of the toner is small, the ears become short and dense, and Since the bond between the toners cannot be released, one ear becomes thick and short, and becomes an agglomerated state.

In the latter case, that is, when the ears become thick, the toner inside the ears becomes insufficiently charged. Therefore, simply reduce the ratio of the amount of magnetic material in the toner,
There is a problem in that when trying to shorten the ears, deterioration of image quality such as fogging due to poor charging of toner is likely to occur. Further, in general, the magnetic material also serves as a coloring material, so if the amount of the magnetic material is reduced as it is, it is easily considered that the image density becomes insufficient. Therefore, as described above, the magnetic toner and the developing device for the magnetic toner, which reduce the magnetic strength of the magnetic toner without reducing the amount of the magnetic material in the magnetic toner, and improve the charge imparting stability and the image reproducibility, are provided. There wasn't enough.

(Sixth Invention) As described above, the magnetic 1
The two disadvantages of the component system are that the charge application process is insufficient and that the image reproducibility is poor because the toner contains a magnetic material.

As a method of solving the image reproducibility, it is conceivable to make the ears of the toner short and dense, and as a means therefor, it is easy to imagine a method of reducing the ratio of the amount of magnetic material in the toner. Yes, but in general, current development systems rely on the absolute value of the specific charge of the toner,
It is difficult to develop a toner containing a reduced amount of magnetic material for the following reasons.

That is, if the radius of one toner is R, the charge amount is Q, and the density is ρ, the specific charge Q / M of the toner can be expressed as Q / M = 3Q / 4πρR ³ . The density of the magnetic substance in the toner of a general magnetic one-component toner is several times higher than the density of the binder resin. Therefore, the toner density ρ decreases as the amount of magnetic material in the toner decreases, and the specific charge increases conversely. As is well known, an increase in specific charge tends to cause a low image density. In particular, as is clear from the above equation, the tendency becomes more remarkable as the toner particle size is reduced.

Further, the image quality of a copied image in the magnetic one-component developing system is greatly influenced by the cohesiveness of the toner. As is well known, when the amount of the magnetic material contained in the magnetic toner is reduced, the magnetic toner easily aggregates in the developing device. It is considered that this is because the magnetic repulsive force due to the magnetic characteristics of the magnetic toner is relatively weakened against the powder cohesive force between the magnetic toner particles.

That is, when the strength of magnetization of the toner is large, a strong attractive force along the magnetic field direction and a strong repulsive force in the direction perpendicular to the magnetic field are generated between the toner particles. Therefore, the ears formed by the toner become long and coarse, and one ears become thin, and conversely, when the magnetization of the toner is small, the ears become short and dense, and Since the bond between the toners cannot be released, one ear becomes thick and short, and becomes an agglomerated state.

In the latter case, that is, when the ears become thick, the toner inside the ears becomes insufficiently charged. Therefore, simply reduce the ratio of the amount of magnetic material in the toner,
There is a problem in that when trying to shorten the ears, deterioration of image quality such as fogging due to poor charging of toner is likely to occur.

Further, in general, the magnetic substance also functions as a coloring material, and therefore it is easily conceivable that the image density becomes insufficient if the amount of the magnetic substance is reduced as it is. Therefore,
As described above, it is still sufficient for the magnetic toner and its developing device to reduce the magnetization intensity of the magnetic toner without reducing the amount of the magnetic substance in the magnetic toner, and improve the charging stability and the image reproducibility. There was no such thing.

[0062]

[Means and Actions for Solving the Problems]

(First invention) According to the present inventor, a magnetic toner containing a magnetic material, a developer carrying body carrying a developer containing the magnetic toner on the surface, and a developer carrying body disposed inside the developer carrying body. In a developing device having a magnet and a regulating member that regulates the application of the developer on the developer carrier, the strength of magnetization of the magnetic substance contained in the magnetic toner in the magnetic field 1KOe and the magnetic property of the magnetic toner. By adjusting the body content,
Further, in the developing device, at least one counter electrode for the developer carrying member is arranged near the developer carrying member,
Further, by applying an alternating electric field between the counter electrode and the developer carrying member, at least one or more of the counter electrode is provided on the developer carrying member with respect to the developer regulating member. By being arranged on the downstream side in the transport direction,
The magnetic reproducibility is improved by reducing the magnetization intensity of the magnetic toner without reducing the amount of magnetic material in the magnetic toner, and stabilizing the charge application process to the magnetic toner.

The constitution of the magnetic toner used in the present invention will be described in more detail below. The range of the magnetization intensity of the magnetic material used in the present invention is 10 to 40 emu / g.
20-40 emu / g is preferable. The magnetic field strength of the magnetic material used here is the value when the magnetic field is 1 KOe, because it is disposed inside the developer carrier of the developing device used in the present invention. The magnetic field generated by the magnet
Since the surface of the developer carrier has a maximum of about 1 KOe,
This is because the strength of the magnetization at the magnetic field of 1 KOe is the most suitable value when considering the magnetic characteristics of the magnetic toner in the developing device.

For the measurement of magnetic force, VSM manufactured by Toei Industry Co., Ltd. was used. The strength of magnetization in a magnetic field of 1 KOe is 10 emu
If it is less than / g, toner scattering becomes a problem, and the transportability is poor and a uniform and good image cannot be obtained. If the magnetization intensity is higher than 40 emu / g, the magnetic toner becomes long and the image reproducibility may be poor, that is, fine line reproducibility and gradation may be poor. The holding power is also related to the image quality. The range of holding power is preferably 50 to 200 Oe.
Although the reason is not clear, if the holding force is less than 50 Oe, fog in the background portion is likely to occur. Holding power is 200O
If it is larger than e, the transportability may deteriorate, the coating may not be good, and the image quality such as uneven image density may deteriorate.

The particle size of the magnetic material is related to the charge amount of the toner and the coloring power. The particle diameter of the magnetic material is indicated by the Feret diameter in the horizontal direction.
The measurement was carried out by magnifying a photograph of a magnetic body of 10,000 times obtained by a transmission electron microscope by a factor of 4 to obtain a photograph of 40,000 times, and randomly selecting 250 magnetic bodies and measuring the diameter thereof. The average particle size is then calculated. Average particle size is 0.05 to 0.5
μm. The thickness is preferably 0.08 to 0.4 μm, more preferably 0.1 to 0.4 μm. Average particle size 0.05
If it is less than μm, it is difficult to control the charge and is easily oxidized, resulting in poor handleability. If the average particle size is larger than 0.5 μm, the coloring power is insufficient, and the toner is non-uniformly charged, which may cause fog in the background portion.

The content (% by weight) of the magnetic substance is 30 to 60.
% By weight. If the amount is less than 30% by weight, there is a problem that the transportability becomes insufficient, image density unevenness or the like occurs, the aggregation of ears becomes difficult to loosen, and fog occurs in the background portion. If it exceeds 60% by weight, the effect of the present invention is reduced and the image reproducibility is deteriorated. When the weight average particle diameter Dt of the toner is 7.5 μm or less,
The content (% by weight) of the magnetic substance can be derived by the following formula. {WT =-(10/3) Dt + (70 ± 15)}

If the charge amount of the toner is not appropriate, a good image cannot be obtained. The toner charge amount was determined by the blow-off measurement method. The measuring instrument used was that manufactured by Toshiba Chemical Corporation. EFV200 / 300 (manufactured by Nippon Iron Powder Co., Ltd.) was used as a carrier, the toner concentration was 2% by weight, and the mixing time was about 2 minutes. The absolute value of the measured value at this time is 5 to 50 μc / g
Is good. It is preferably 5 to 40 μc / g. 5 μc /
When it is less than g, the sharpness of the image is deteriorated and the fog in the background portion is caused. Further, in a high temperature and high humidity environment, a decrease in image density becomes a problem. If it is larger than 50 μc / g, the electrostatic cohesive force becomes large and the ears are hard to be loosened, and the image quality deteriorates. In particular, in a low temperature and low humidity environment, the mirroring power with respect to the toner carrying member becomes larger than necessary, so that the image density is lowered.

The particle size of the toner of the present invention was measured with a TA-II type machine manufactured by Coulter Counter. An aperture of 100 μm is used, and the particle size is a weight average diameter,
The coefficient of change was calculated by dividing the standard deviation of the volume distribution by the volume average diameter and multiplying by 100. As the binder resin for toner,
Homopolymers of styrene and its substitution products such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene, styrene-p-chlorostyrene copolymers, styrene-vinyl-toluene copolymers and their copolymers; styrene-methyl acrylate Copolymers of styrene and acrylic ester such as copolymers, styrene-ethyl acrylate copolymers, styrene-n-butyl acrylate copolymers; styrene-methyl methacrylate copolymers, styrene-ethyl methacrylate Copolymers, copolymers of styrene and methacrylic acid esters such as styrene-n-butyl methacrylate copolymers; multi-component copolymers of styrene and acrylic acid esters and methacrylic acid esters; other styrene-acrylonitrile copolymers , Styrene-vinyl methyl ether copolymer, styrene Styrene-based copolymerization of styrene and other vinyl-based polymerizable monomers such as butadiene copolymer, styrene-vinyl methyl ketone copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid ester copolymer Combined; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyester, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid, phenol resin, aliphatic or alicyclic hydrocarbon resin, petroleum resin, chlorinated paraffin, etc. Alternatively, they can be mixed and used.

In particular, as a binder resin for a toner which is subjected to a pressure fixing system, low molecular weight polyethylene, low molecular weight polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, higher fatty acid, polyamide resin, Polyester resins and the like can be used alone or in combination. If the polymer, copolymer or polymer blend used contains vinyl aromatic or acrylic monomer represented by styrene in an amount of 40% by weight or more, more desirable results are obtained.

Any appropriate pigment or dye can be used as a colorant in the toner. For example, carbon black, phthalocyanine blue, ultramarine, quinacridone,
There are known dyes and pigments such as benzidine yellow. As a method for producing the toner containing the magnetic material used in the present invention, a conventionally known method may be used. That is, a binder resin, a charge control agent, a colorant, a magnetic material, and other additives are powder-mixed in advance with a Henschel mixer or the like, and then this is kneaded with a roll mill heated to about 150 ° C. for about 30 minutes and kneaded. The product is obtained, cooled, pulverized, and if necessary classified to obtain a toner composition. If necessary, a fluidity imparting agent, a lubricant, an abrasive, a cleaning aid, a resistance adjusting agent, a charge control agent and the like may be added internally or externally.

(Second Invention) According to the present invention, a magnetic toner containing a magnetic material, a developer carrying body carrying a developer containing the magnetic toner on its surface, and a developer carrying body inside the developer carrying body. In a developing device having a magnet arranged and a regulating member for regulating the application of the developer on the developer carrying member, the strength of the magnetization of the magnetic substance contained in the magnetic toner in the magnetic field 1KOe and the magnetic toner By adjusting the content of the magnetic material in the developing device, and in the developing device, at least one or more counter electrodes are provided on the developer carrying member on the developer carrying member with respect to the developer carrying member. Is arranged in the vicinity of the developer carrying body on the downstream side in the developer carrying direction of the above, and an alternating electric field is applied between the counter electrode and the developer carrying body, and at least the developer carrying body of the counter electrode. The surface facing the By configuring a member indicating the polarity of the polarity and different polarity,

Charge is imparted to the magnetic toner even when the time for the number of vibrations of the developer due to the alternating electric field is not sufficient with respect to the time for the developer to pass between the counter electrode and the developer carrying member. This is to improve the image reproducibility by stabilizing the process and reducing the magnetic strength of the magnetic toner without reducing the amount of magnetic material in the magnetic toner. Further, at least the surface of the counter electrode facing the developer carrying member is made of a member exhibiting a polarity opposite to the charging polarity of the magnetic toner and exhibiting an insulating property, and The number of vibrations of the developer due to the alternating electric field with respect to the time during which the developer passes between the counter electrode and the developer carrying member while preventing the voltage leakage of the alternating electric field between the developer carrying body and the counter electrode. Even when the time is not sufficiently taken, the process of imparting electric charge to the magnetic toner is stabilized, and the strength of magnetization of the magnetic toner is reduced without reducing the amount of magnetic material in the magnetic toner, thereby improving image reproducibility. Is an improvement.

The structure of the magnetic toner used in the present invention will be described in more detail below. The range of the magnetization intensity of the magnetic material used in the present invention is 10 to 40 emu / g. 20-40 emu / g is preferable. The magnetic field strength of the magnetic material used here is the value when the magnetic field is 1 KOe. Because the magnetic field generated by the magnet disposed inside the developer carrier of the developing device used in the present invention is about 1 KOe at the maximum on the surface of the developer carrier, the magnetic field of 1 KOe This is because the strength of magnetization is the most suitable value in consideration of the magnetic characteristics of the magnetic toner in the developing device.

The magnetic force was measured using VSM manufactured by Toei Industry Co., Ltd. The strength of magnetization in a magnetic field of 1 KOe is 10 emu
If it is less than / g, toner scattering becomes a problem, and the transportability is poor and a uniform and good image cannot be obtained. If the magnetization intensity is higher than 40 emu / g, the magnetic toner becomes long and the image reproducibility may be poor, that is, fine line reproducibility and gradation may be poor. The holding power is also related to the image quality. The range of holding power is preferably 50 to 200 Oe.
Although the reason is not clear, if the holding force is less than 50 Oe, fog in the background portion is likely to occur. Holding power is 200O
If it is larger than e, the transportability may deteriorate, the coating may not be good, and the image quality such as uneven image density may deteriorate.

The particle size of the magnetic material is related to the charge amount of the toner and the coloring power. The particle diameter of the magnetic material is indicated by the Feret diameter in the horizontal direction.
The measurement was carried out by magnifying a photograph of a magnetic body of 10,000 times obtained by a transmission electron microscope by a factor of 4 to obtain a photograph of 40,000 times, and randomly selecting 250 magnetic bodies and measuring the diameter thereof. The average particle size is then calculated. Average particle size is 0.05 to 0.5
μm. The thickness is preferably 0.08 to 0.4 μm, more preferably 0.1 to 0.4 μm. Average particle size 0.05
If it is less than μm, it is difficult to control the charge and is easily oxidized, resulting in poor handleability. If the average particle size is larger than 0.5 μm, the coloring power is insufficient, and the toner is non-uniformly charged, which may cause fog in the background portion.

The content (% by weight) of the magnetic substance is 30 to 60.
% By weight. If the amount is less than 30% by weight, there is a problem that the transportability becomes insufficient, image density unevenness or the like occurs, the aggregation of ears becomes difficult to loosen, and fog occurs in the background portion. If it exceeds 60% by weight, the effect of the present invention is reduced and the image reproducibility is deteriorated. When the weight average particle diameter Dt of the toner is 7.5 μm or less,
The content (% by weight) of the magnetic substance can be derived by the following formula. {WT =-(10/3) Dt + (70 ± 15)}

If the charge amount of the toner is not appropriate, a good image cannot be obtained. The toner charge amount was determined by the blow-off measurement method. The measuring instrument used was that manufactured by Toshiba Chemical Corporation. EFV200 / 300 (manufactured by Nippon Iron Powder Co., Ltd.) was used as a carrier, the toner concentration was 2% by weight, and the mixing time was about 2 minutes. The absolute value of the measured value at this time is 5 to 50 μc / g
Is good. It is preferably 5 to 40 μc / g. 5 μc /
When it is less than g, the sharpness of the image is deteriorated and the fog in the background portion is caused. Further, in a high temperature and high humidity environment, a decrease in image density becomes a problem. If it is larger than 50 μc / g, the electrostatic cohesive force becomes large and the ears are hard to be loosened, and the image quality deteriorates. In particular, in a low temperature and low humidity environment, the mirroring power with respect to the toner carrying member becomes larger than necessary, so that the image density is lowered.

The particle size of the toner of the present invention was measured with a TA-II type machine manufactured by Coulter Counter. An aperture of 100 μm is used, and the particle size is a weight average diameter,
The coefficient of change was calculated by dividing the standard deviation of the volume distribution by the volume average diameter and multiplying by 100. As the binder resin for toner,
Homopolymers of styrene and its substitution products such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene, styrene-p-chlorostyrene copolymers, styrene-vinyl-toluene copolymers and their copolymers; styrene-methyl acrylate Copolymers of styrene and acrylic ester such as copolymers, styrene-ethyl acrylate copolymers, styrene-n-butyl acrylate copolymers; styrene-methyl methacrylate copolymers, styrene-ethyl methacrylate Copolymers, copolymers of styrene and methacrylic acid esters such as styrene-n-butyl methacrylate copolymers; multi-component copolymers of styrene and acrylic acid esters and methacrylic acid esters; other styrene-acrylonitrile copolymers , Styrene-vinyl methyl ether copolymer, styrene Styrene-based copolymerization of styrene and other vinyl-based polymerizable monomers such as butadiene copolymer, styrene-vinyl methyl ketone copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid ester copolymer Combined; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyester, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid, phenol resin, aliphatic or alicyclic hydrocarbon resin, petroleum resin, chlorinated paraffin, etc. Alternatively, they can be mixed and used.

In particular, as a binder resin for a toner to be subjected to a pressure fixing system, low molecular weight polyethylene, low molecular weight polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, higher fatty acid, polyamide resin, Polyester resins and the like can be used alone or in combination. If the polymer, copolymer or polymer blend used contains vinyl aromatic or acrylic monomer represented by styrene in an amount of 40% by weight or more, more desirable results are obtained. Any appropriate pigment or dye can be used as a colorant in the toner. For example, there are known dyes and pigments such as carbon black, phthalocyanine blue, ultramarine blue, quinacridone, and benzidine yellow.

As a method for producing the toner containing the magnetic material used in the present invention, a conventionally known method may be used. That is, a binder resin, a charge control agent, a colorant, a magnetic substance, and other additives are previously powder-mixed with a Henschel mixer or the like, and then this is kneaded with a roll mill heated to about 150 ° C. for about 30 minutes,
A kneaded product is obtained, cooled, pulverized, and if necessary classified to obtain a toner composition. If necessary, a fluidizing agent, a lubricant,
Abrasives, cleaning aids, resistance control agents, charge control agents, etc. may be added internally or externally.

(Third Invention) According to the present invention, a magnetic toner containing a magnetic material, a developer carrying body carrying a developer containing the magnetic toner on its surface, and a developer carrying body inside the developer carrying body. In a developing device having a magnet arranged and a regulating member for regulating the application of the developer on the developer carrying member, the strength of the magnetization of the magnetic substance contained in the magnetic toner in the magnetic field 1KOe and the magnetic toner By adjusting the content of the magnetic substance in the developing device, and in the developing device, at least one counter electrode is provided for the developer carrying member, and the developer carrying member is provided for the developer regulating member. A structure arranged near the developer carrying member on the downstream side in the developer carrying direction, and an alternating electric field is applied between the counter electrode and the developer carrying member;
At least the surface of the counter electrode facing the developer carrying member is covered with an insulating member,
Preventing voltage leakage of an alternating electric field between the developer carrying member and the counter electrode under high humidity, and reducing the magnetic strength of the magnetic toner without reducing the amount of the magnetic substance in the magnetic toner, In addition, the process of imparting a charge to the magnetic toner is stabilized and the image reproducibility is improved. Further, the strength of magnetization of the magnetic toner is reduced without reducing the amount of magnetic material in the magnetic toner,
The image reproducibility is improved.

The structure of the magnetic toner used in the present invention will be described in more detail below. The range of the magnetization intensity of the magnetic material used in the present invention is 10 to 40 emu / g. 20-40 emu / g is preferable. The magnetic field strength of the magnetic material used here is the value when the magnetic field is 1 KOe. Because the magnetic field generated by the magnet disposed inside the developer carrier of the developing device used in the present invention is about 1 KOe at the maximum on the surface of the developer carrier, the magnetic field of 1 KOe This is because the strength of magnetization is the most suitable value in consideration of the magnetic characteristics of the magnetic toner in the developing device.

For the measurement of magnetic force, VSM manufactured by Toei Industry Co., Ltd. was used. The strength of magnetization in a magnetic field of 1 KOe is 10 emu
If it is less than / g, toner scattering becomes a problem, and the transportability is poor and a uniform and good image cannot be obtained. If the magnetization intensity is higher than 40 emu / g, the magnetic toner becomes long and the image reproducibility may be poor, that is, fine line reproducibility and gradation may be poor. The holding power is also related to the image quality. The range of holding power is preferably 50 to 200 Oe.
Although the reason is not clear, if the holding force is less than 50 Oe, fog in the background portion is likely to occur. Holding power is 200O
If it is larger than e, the transportability may deteriorate, the coating may not be good, and the image quality such as uneven image density may deteriorate.

The particle size of the magnetic material is related to the charge amount and the coloring power of the toner. The particle diameter of the magnetic material is indicated by the Feret diameter in the horizontal direction.
The measurement was carried out by magnifying a photograph of a magnetic body of 10,000 times obtained by a transmission electron microscope by a factor of 4 to obtain a photograph of 40,000 times, and randomly selecting 250 magnetic bodies and measuring the diameter thereof. The average particle size is then calculated. Average particle size is 0.05 to 0.5
μm. The thickness is preferably 0.08 to 0.4 μm, more preferably 0.1 to 0.4 μm. Average particle size 0.05
If it is less than μm, it is difficult to control the charge and is easily oxidized, resulting in poor handleability. If the average particle size is larger than 0.5 μm, the coloring power is insufficient, and the toner is non-uniformly charged, which may cause fog in the background portion.

The content (% by weight) of the magnetic substance is 30 to 60.
% By weight. If the amount is less than 30% by weight, there is a problem that the transportability becomes insufficient, image density unevenness or the like occurs, the aggregation of ears becomes difficult to loosen, and fog occurs in the background portion. If it exceeds 60% by weight, the effect of the present invention is reduced and the image reproducibility is deteriorated. When the weight average particle diameter Dt of the toner is 7.5 μm or less,
The content (% by weight) of the magnetic substance can be derived by the following formula. {WT =-(10/3) Dt + (70 ± 15)}

If the charge amount of the toner is not appropriate, a good image cannot be obtained. The toner charge amount was determined by the blow-off measurement method. The measuring instrument used was that manufactured by Toshiba Chemical Corporation. EFV200 / 300 (manufactured by Nippon Iron Powder Co., Ltd.) was used as a carrier, the toner concentration was 2% by weight, and the mixing time was about 2 minutes. The absolute value of the measured value at this time is 5 to 50 μc / g
Is good. It is preferably 5 to 40 μc / g. 5 μc /
When it is less than g, the sharpness of the image is deteriorated and the fog in the background portion is caused. Further, in a high temperature and high humidity environment, a decrease in image density becomes a problem. If it is larger than 50 μc / g, the electrostatic cohesive force becomes large and the ears are hard to be loosened, and the image quality deteriorates. In particular, in a low temperature and low humidity environment, the mirroring power with respect to the toner carrying member becomes larger than necessary, so that the image density is lowered.

The particle size of the toner of the present invention was measured with a TA-II type machine manufactured by Coulter Counter. An aperture of 100 μm is used, and the particle size is a weight average diameter,
The coefficient of change was calculated by dividing the standard deviation of the volume distribution by the volume average diameter and multiplying by 100. As the binder resin for toner,
Homopolymers of styrene and its substitution products such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene, styrene-p-chlorostyrene copolymers, styrene-vinyl-toluene copolymers and their copolymers; styrene-methyl acrylate Copolymers of styrene and acrylic ester such as copolymers, styrene-ethyl acrylate copolymers, styrene-n-butyl acrylate copolymers; styrene-methyl methacrylate copolymers, styrene-ethyl methacrylate Copolymers, copolymers of styrene and methacrylic acid esters such as styrene-n-butyl methacrylate copolymers; multi-component copolymers of styrene and acrylic acid esters and methacrylic acid esters; other styrene-acrylonitrile copolymers , Styrene-vinyl methyl ether copolymer, styrene Styrene-based copolymerization of styrene and other vinyl-based polymerizable monomers such as butadiene copolymer, styrene-vinyl methyl ketone copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid ester copolymer Combined; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyester, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid, phenol resin, aliphatic or alicyclic hydrocarbon resin, petroleum resin, chlorinated paraffin, etc. Alternatively, they can be mixed and used.

In particular, as a binder resin for a toner to be subjected to a pressure fixing method, low molecular weight polyethylene, low molecular weight polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, higher fatty acid, polyamide resin, Polyester resins and the like can be used alone or in combination. If the polymer, copolymer or polymer blend used contains vinyl aromatic or acrylic monomer represented by styrene in an amount of 40% by weight or more, more desirable results are obtained. Any appropriate pigment or dye can be used as a colorant in the toner. For example, there are known dyes and pigments such as carbon black, phthalocyanine blue, ultramarine blue, quinacridone, and benzidine yellow.

As a method for producing a toner containing a magnetic material used in the present invention, a conventionally known method may be used. That is, a binder resin, a charge control agent, a colorant, a magnetic substance, and other additives are previously powder-mixed with a Henschel mixer or the like, and then this is kneaded with a roll mill heated to about 150 ° C. for about 30 minutes,
A kneaded product is obtained, cooled, pulverized, and if necessary classified to obtain a toner composition. If necessary, a fluidizing agent, a lubricant,
Abrasives, cleaning aids, resistance control agents, charge control agents, etc. may be added internally or externally.

(Fourth Invention) According to the present invention, a magnetic toner containing a magnetic material, a developer carrying body carrying a developer containing the magnetic toner on the surface, and a developer carrying body inside the developer carrying body. In a developing device having a magnet arranged and a regulating member for regulating the application of the developer on the developer carrying member, the strength of the magnetization of the magnetic substance contained in the magnetic toner in the magnetic field 1KOe and the magnetic toner By adjusting the content of the magnetic substance, or by disposing a vibrating member in the vicinity of the regulating member and arranging a vibration transmitter for vibrating the vibrating member,
It is intended to stabilize the process of applying an electric charge to the magnetic toner and improve the image reproducibility.

The constitution of the magnetic toner used in the present invention will be described in more detail below. The range of the magnetization intensity of the magnetic material used in the present invention is 10 to 40 emu / g. 20-40 emu / g is preferable. The magnetic field strength of the magnetic material used here is the value when the magnetic field is 1 KOe. Because the magnetic field generated by the magnet disposed inside the developer carrying member of the developing device used in the present invention is about 1 KOe at the maximum on the surface of the developer carrying member, the magnetic field of 1 KOe This is because the strength of magnetization is the most suitable value in consideration of the magnetic characteristics of the magnetic toner in the developing device.

For the measurement of the magnetic force, VSM manufactured by Toei Industry Co., Ltd. was used. The strength of magnetization in a magnetic field of 1 KOe is 10 emu
If it is less than / g, toner scattering becomes a problem, and the transportability is poor and a uniform and good image cannot be obtained. If the magnetization intensity is higher than 40 emu / g, the magnetic toner becomes long and the image reproducibility may be poor, that is, fine line reproducibility and gradation may be poor. The holding power is also related to the image quality. The range of holding power is preferably 50 to 200 Oe.
Although the reason is not clear, if the holding force is less than 50 Oe, fog in the background portion is likely to occur. Holding power is 200O
If it is larger than e, the transportability may deteriorate, the coating may not be good, and the image quality such as uneven image density may deteriorate.

The particle size of the magnetic material is related to the charge amount of the toner and the coloring power. The particle diameter of the magnetic material is indicated by the Feret diameter in the horizontal direction.
The measurement was carried out by magnifying a photograph of a magnetic body of 10,000 times obtained by a transmission electron microscope by a factor of 4 to obtain a photograph of 40,000 times, and randomly selecting 250 magnetic bodies and measuring the diameter thereof. The average particle size is then calculated. Average particle size is 0.05 to 0.5
μm. The thickness is preferably 0.08 to 0.4 μm, more preferably 0.1 to 0.4 μm. Average particle size 0.05
If it is less than μm, it is difficult to control the charge and is easily oxidized, resulting in poor handleability. If the average particle size is larger than 0.5 μm, the coloring power is insufficient, and the toner is non-uniformly charged, which may cause fog in the background portion.

The content (% by weight) of the magnetic substance is 30 to 60.
% By weight. If the amount is less than 30% by weight, there is a problem that the transportability becomes insufficient, image density unevenness or the like occurs, the aggregation of ears becomes difficult to loosen, and fog occurs in the background portion. If it exceeds 60% by weight, the effect of the present invention is reduced and the image reproducibility is deteriorated. When the weight average particle diameter Dt of the toner is 7.5 μm or less,
The content (% by weight) of the magnetic substance can be derived by the following formula. {WT =-(10/3) Dt + (70 ± 15)}

If the charge amount of the toner is not appropriate, a good image cannot be obtained. The toner charge amount was determined by the blow-off measurement method. The measuring instrument used was that manufactured by Toshiba Chemical Corporation. EFV200 / 300 (manufactured by Nippon Iron Powder Co., Ltd.) was used as a carrier, the toner concentration was 2% by weight, and the mixing time was about 2 minutes. The absolute value of the measured value at this time is 5 to 50 μc / g
Is good. It is preferably 5 to 40 μc / g. 5 μc /
When it is less than g, the sharpness of the image is deteriorated and the fog in the background portion is caused. Further, in a high temperature and high humidity environment, a decrease in image density becomes a problem. If it is more than 50 μc / g, the electrostatic cohesive force becomes large and the ears are not loosened and the image is developed as it is. Since the size becomes larger than necessary, the image density is lowered.

The particle size of the toner of the present invention was measured with a TA-II type machine manufactured by Coulter Counter. An aperture of 100 μm is used, and the particle size is a weight average diameter,
The coefficient of change was calculated by dividing the standard deviation of the volume distribution by the volume average diameter and multiplying by 100. As the binder resin for toner,
Homopolymers of styrene and its substitution products such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene, styrene-p-chlorostyrene copolymers, styrene-vinyl-toluene copolymers and their copolymers; styrene-methyl acrylate Copolymers of styrene and acrylic ester such as copolymers, styrene-ethyl acrylate copolymers, styrene-n-butyl acrylate copolymers; styrene-methyl methacrylate copolymers, styrene-ethyl methacrylate Copolymers, copolymers of styrene and methacrylic acid esters such as styrene-n-butyl methacrylate copolymers; multi-component copolymers of styrene and acrylic acid esters and methacrylic acid esters; other styrene-acrylonitrile copolymers , Styrene-vinyl methyl ether copolymer, styrene Styrene-based copolymerization of styrene and other vinyl-based polymerizable monomers such as butadiene copolymer, styrene-vinyl methyl ketone copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid ester copolymer Combined; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyester, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid, phenol resin, aliphatic or alicyclic hydrocarbon resin, petroleum resin, chlorinated paraffin, etc. Alternatively, they can be mixed and used.

In particular, as a binder resin for a toner to be subjected to a pressure fixing method, low molecular weight polyethylene, low molecular weight polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, higher fatty acid, polyamide resin, Polyester resins and the like can be used alone or in combination. When the polymer, copolymer or polymer blend used contains 40% by weight or more of a vinyl aromatic or acrylic monomer represented by styrene, more desirable results are obtained. Any appropriate pigment or dye can be used as a colorant in the toner. For example, there are known dyes and pigments such as carbon black, phthalocyanine blue, ultramarine blue, quinacridone, and benzidine yellow.

As a method for producing a toner containing a magnetic material used in the present invention, a conventionally known method may be used. That is, a binder resin, a charge control agent, a colorant, a magnetic substance, and other additives are previously powder-mixed with a Henschel mixer or the like, and then this is kneaded with a roll mill heated to about 150 ° C. for about 30 minutes,
A kneaded product is obtained, cooled, pulverized, and if necessary classified to obtain a toner composition. If necessary, a fluidizing agent, a lubricant,
Abrasives, cleaning aids, resistance control agents, charge control agents, etc. may be added internally or externally.

(Fifth Invention) According to the present inventor, a magnetic toner containing a magnetic material, a developer carrying body carrying a developer containing the magnetic toner on its surface, and the inside of the developer carrying body In a developing device having a magnet disposed in the magnetic toner and a regulating member for regulating the application of the developer on the developer carrying member, the strength of magnetization of the magnetic substance contained in the magnetic toner in the magnetic field 1KOe and the magnetic toner. By adjusting the content of the magnetic substance therein, and by applying an alternating electric field between the electrode disposed on the elastic body regulating member and the magnetic substance carrier, the process of giving a charge to the magnetic toner can be performed. It stabilizes and improves the image reproducibility.

The constitution of the magnetic toner used in the present invention will be described in more detail below. The range of the magnetization intensity of the magnetic material used in the present invention is 10 to 40 emu / g.
20-40 emu / g is preferable. The magnetic field strength of the magnetic material used here is the value when the magnetic field is 1 KOe, because it is disposed inside the developer carrier of the developing device used in the present invention. The magnetic field generated by the magnet
Since the surface of the developer carrier has a maximum of about 1 KOe,
This is because the strength of the magnetization at the magnetic field of 1 KOe is the most suitable value when considering the magnetic characteristics of the magnetic toner in the developing device.

For the measurement of magnetic force, VSM manufactured by Toei Industry Co., Ltd. was used. The strength of magnetization in a magnetic field of 1 KOe is 10 emu
If it is less than / g, toner scattering becomes a problem, and the transportability is poor and a uniform and good image cannot be obtained. If the magnetization intensity is higher than 40 emu / g, the magnetic toner becomes long and the image reproducibility may be poor, that is, fine line reproducibility and gradation may be poor. The holding power is also related to the image quality. The range of holding power is preferably 50 to 200 Oe.
Although the reason is not clear, if the holding force is less than 50 Oe, fog in the background portion is likely to occur. Holding power is 200O
If it is larger than e, the transportability may deteriorate, the coating may not be good, and the image quality such as uneven image density may deteriorate.

The particle size of the magnetic material is related to the charge amount of the toner and the coloring power. The particle diameter of the magnetic material is indicated by the Feret diameter in the horizontal direction.
The measurement was carried out by magnifying a photograph of a magnetic body of 10,000 times obtained by a transmission electron microscope by a factor of 4 to obtain a photograph of 40,000 times, and randomly selecting 250 magnetic bodies and measuring the diameter thereof. The average particle size is then calculated. Average particle size is 0.05 to 0.5
μm. The thickness is preferably 0.08 to 0.4 μm, more preferably 0.1 to 0.4 μm. Average particle size 0.05
If it is less than μm, it is difficult to control the charge and is easily oxidized, resulting in poor handleability. If the average particle size is larger than 0.5 μm, the coloring power is insufficient, and the toner is non-uniformly charged, which may cause fog in the background portion.

The content (% by weight) of the magnetic substance is 30 to 60.
% By weight. If the amount is less than 30% by weight, there is a problem that the transportability becomes insufficient, image density unevenness or the like occurs, the aggregation of ears becomes difficult to loosen, and fog occurs in the background portion. If it exceeds 60% by weight, the effect of the present invention is reduced and the image reproducibility is deteriorated. When the weight average particle diameter Dt of the toner is 7.5 μm or less,
The content (% by weight) of the magnetic substance can be derived by the following formula. {WT =-(10/3) Dt + (70 ± 15)}

If the charge amount of the toner is not appropriate, a good image cannot be obtained. The toner charge amount was determined by the blow-off measurement method. The measuring instrument used was that manufactured by Toshiba Chemical Corporation. EFV200 / 300 (manufactured by Nippon Iron Powder Co., Ltd.) was used as a carrier, the toner concentration was 2% by weight, and the mixing time was about 2 minutes. The absolute value of the measured value at this time is 5 to 50 μc / g
Is good. It is preferably 5 to 40 μc / g. 5 μc /
When it is less than g, the sharpness of the image is deteriorated and the fog in the background portion is caused. Further, in a high temperature and high humidity environment, a decrease in image density becomes a problem. If it is larger than 50 μc / g, the electrostatic cohesive force becomes large and the ears are hard to be loosened, and the image quality deteriorates. In particular, in a low temperature and low humidity environment, the mirroring power with respect to the toner carrying member becomes larger than necessary, so that the image density is lowered.

The particle size of the toner of the present invention was measured with a TA-II type machine manufactured by Coulter Counter. An aperture of 100 μm is used, and the particle size is a weight average diameter,
The coefficient of change was calculated by dividing the standard deviation of the volume distribution by the volume average diameter and multiplying by 100. As the binder resin for toner,
Homopolymers of styrene and its substitution products such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene, styrene-p-chlorostyrene copolymers, styrene-vinyl-toluene copolymers and their copolymers; styrene-methyl acrylate Copolymers of styrene and acrylic ester such as copolymers, styrene-ethyl acrylate copolymers, styrene-n-butyl acrylate copolymers; styrene-methyl methacrylate copolymers, styrene-ethyl methacrylate Copolymers, copolymers of styrene and methacrylic acid esters such as styrene-n-butyl methacrylate copolymers; multi-component copolymers of styrene and acrylic acid esters and methacrylic acid esters; other styrene-acrylonitrile copolymers , Styrene-vinyl methyl ether copolymer, styrene Styrene-based copolymerization of styrene and other vinyl-based polymerizable monomers such as butadiene copolymer, styrene-vinyl methyl ketone copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid ester copolymer Combined; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyester, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid, phenol resin, aliphatic or alicyclic hydrocarbon resin, petroleum resin, chlorinated paraffin, etc. Alternatively, they can be mixed and used. In particular, as a binder resin for toner to be subjected to a pressure fixing method, low molecular weight polyethylene, low molecular weight polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, higher fatty acid, polyamide resin, polyester resin, etc. Can be used alone or in combination.

When the polymer, copolymer or polymer blend used contains a vinyl aromatic or acrylic monomer represented by styrene in an amount of 40% by weight or more, more desirable results are obtained. Any appropriate pigment or dye can be used as a colorant in the toner. For example, carbon black, phthalocyanine blue, ultramarine,
There are known dyes and pigments such as quinacridone and benzidine yellow.

As a method for producing a toner containing a magnetic material used in the present invention, a conventionally known method may be used. That is, a binder resin, a charge control agent, a colorant, a magnetic substance, and other additives are previously powder-mixed with a Henschel mixer or the like, and then this is kneaded with a roll mill heated to about 150 ° C. for about 30 minutes,
A kneaded product is obtained, cooled, pulverized, and if necessary classified to obtain a toner composition. If necessary, a fluidizing agent, a lubricant,
Abrasives, cleaning aids, resistance control agents, charge control agents, etc. may be added internally or externally.

(Sixth Invention) According to the present inventor, a magnetic toner containing a magnetic material, a developer carrying body carrying a developer containing the magnetic toner on its surface, and the inside of the developer carrying body. In a developing device having a magnet disposed in the magnetic toner and a regulating member for regulating the application of the developer on the developer carrying member, the strength of magnetization of the magnetic substance contained in the magnetic toner in the magnetic field 1KOe and the magnetic toner. By adjusting the content of the magnetic substance therein and by disposing a grid-like member in the vicinity of the regulating member, the process of imparting charge to the magnetic toner was stabilized and the image reproducibility was improved It is a thing.

The structure of the magnetic toner used in the present invention will be described in more detail below. The range of the magnetization intensity of the magnetic material used in the present invention is 10 to 40 emu / g.
20-40 emu / g is preferable. The magnetic field strength of the magnetic material used here is the value when the magnetic field is 1 KOe, because it is disposed inside the developer carrier of the developing device used in the present invention. The magnetic field generated by the magnet
Since the surface of the developer carrier has a maximum of about 1 KOe,
This is because the strength of the magnetization at the magnetic field of 1 KOe is the most suitable value when considering the magnetic characteristics of the magnetic toner in the developing device.

For the measurement of magnetic force, VSM manufactured by Toei Industry Co., Ltd. was used. The strength of magnetization in a magnetic field of 1 KOe is 10 emu
If it is less than / g, toner scattering becomes a problem, and the transportability is poor and a uniform and good image cannot be obtained. If the magnetization intensity is higher than 40 emu / g, the magnetic toner becomes long and the image reproducibility may be poor, that is, fine line reproducibility and gradation may be poor. The holding power is also related to the image quality. The range of holding power is preferably 50 to 200 Oe.
Although the reason is not clear, if the holding force is less than 50 Oe, fog in the background portion is likely to occur. Holding power is 200O
If it is larger than e, the transportability may deteriorate, the coating may not be good, and the image quality such as uneven image density may deteriorate.

The particle size of the magnetic material is related to the charge amount of the toner and the coloring power. The particle diameter of the magnetic material is indicated by the Feret diameter in the horizontal direction.
The measurement was carried out by magnifying a photograph of a magnetic body of 10,000 times obtained by a transmission electron microscope by a factor of 4 to obtain a photograph of 40,000 times, and randomly selecting 250 magnetic bodies and measuring the diameter thereof. The average particle size is then calculated. Average particle size is 0.05 to 0.5
μm. The thickness is preferably 0.08 to 0.4 μm, more preferably 0.1 to 0.4 μm. Average particle size 0.05
If it is less than μm, it is difficult to control the charge and is easily oxidized, resulting in poor handleability. If the average particle size is larger than 0.5 μm, the coloring power is insufficient, and the toner is non-uniformly charged, which may cause fog in the background portion.

The content (% by weight) of the magnetic substance is 30 to 60.
% By weight. If the amount is less than 30% by weight, there is a problem that the transportability becomes insufficient, image density unevenness or the like occurs, the aggregation of ears becomes difficult to loosen, and fog occurs in the background portion. If it exceeds 60% by weight, the effect of the present invention is reduced and the image reproducibility is deteriorated. When the weight average particle diameter Dt of the toner is 7.5 μm or less,
The content (% by weight) of the magnetic substance can be derived by the following formula. {WT =-(10/3) Dt + (70 ± 15)}

If the charge amount of the toner is not appropriate, a good image cannot be obtained. The toner charge amount was determined by the blow-off measurement method. The measuring instrument used was that manufactured by Toshiba Chemical Corporation. EFV200 / 300 (manufactured by Nippon Iron Powder Co., Ltd.) was used as a carrier, the toner concentration was 2% by weight, and the mixing time was about 2 minutes. The absolute value of the measured value at this time is 5 to 50 μc / g
Is good. It is preferably 5 to 40 μc / g. 5 μc /
When it is less than g, the sharpness of the image is deteriorated and the fog in the background portion is caused. Further, in a high temperature and high humidity environment, a decrease in image density becomes a problem. If it is more than 50 μc / g, the electrostatic cohesive force becomes large and the ears are not loosened and the image is developed as it is. Since the size becomes larger than necessary, the image density is lowered.

The particle size of the toner of the present invention was measured with a TA-II type machine manufactured by Coulter Counter. An aperture of 100 μm is used, and the particle size is a weight average diameter,
The coefficient of change was calculated by dividing the standard deviation of the volume distribution by the volume average diameter and multiplying by 100. As the binder resin for toner,
Homopolymers of styrene and its substitution products such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene, styrene-p-chlorostyrene copolymers, styrene-vinyl-toluene copolymers and their copolymers; styrene-methyl acrylate Copolymers of styrene and acrylic ester such as copolymers, styrene-ethyl acrylate copolymers, styrene-n-butyl acrylate copolymers; styrene-methyl methacrylate copolymers, styrene-ethyl methacrylate Copolymers, copolymers of styrene and methacrylic acid esters such as styrene-n-butyl methacrylate copolymers; multi-component copolymers of styrene and acrylic acid esters and methacrylic acid esters; other styrene-acrylonitrile copolymers , Styrene-vinyl methyl ether copolymer, styrene Styrene-based copolymerization of styrene and other vinyl-based polymerizable monomers such as butadiene copolymer, styrene-vinyl methyl ketone copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid ester copolymer Combined; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyester, polyamide, epoxy resin, polyvinyl butyral, polyacrylic acid, phenol resin, aliphatic or alicyclic hydrocarbon resin, petroleum resin, chlorinated paraffin, etc. Alternatively, they can be mixed and used.

In particular, as a binder resin for a toner which is subjected to a pressure fixing system, low molecular weight polyethylene, low molecular weight polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, higher fatty acid, polyamide resin, Polyester resins and the like can be used alone or in combination. If the polymer, copolymer or polymer blend used contains vinyl aromatic or acrylic monomer represented by styrene in an amount of 40% by weight or more, more desirable results are obtained.

Any suitable pigment or dye can be used as a colorant in the toner. For example, carbon black, phthalocyanine blue, ultramarine, quinacridone,
There are known dyes and pigments such as benzidine yellow. As a method for producing the toner containing the magnetic material used in the present invention, a conventionally known method may be used. That is, a binder resin, a charge control agent, a colorant, a magnetic material, and other additives are powder-mixed in advance with a Henschel mixer or the like, and then this is kneaded with a roll mill heated to about 150 ° C. for about 30 minutes and kneaded. The product is obtained, cooled, pulverized, and if necessary classified to obtain a toner composition. If necessary, a fluidity imparting agent, a lubricant, an abrasive, a cleaning aid, a resistance adjusting agent, a charge control agent and the like may be added internally or externally.

[0117]

【Example】

(First Invention) One embodiment according to the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a developing device which is an embodiment of the present invention. In the figure, 1a is a sleeve made of a non-magnetic metal, which is a developer carrying member that rotates in the direction of the arrow, and 1b.
Is a permanent magnet disposed inside the developing sleeve 1a, 2
Is a magnetic blade that regulates the amount of the developer on the developer carrier made of a magnetic member, 9 is a developing device, and 3 is a carrying member for carrying the magnetic toner in the developing device 9 toward the sleeve 1a. . Reference numeral 5 denotes an electrode, which is a feature of the present invention, and is arranged in the vicinity of the developing sleeve 1a so as to face it. Reference numeral 4 denotes a power source for applying a developing bias to the developing sleeve 1a.

According to the developing device having the above structure, as shown in FIG. 4, the magnetic toner T in the developing container 9 is conveyed in the arrow direction on the developing sleeve 1a, and the developer regulating member 2 is conveyed. When passing through the gap between the developing sleeve 1a and the developing sleeve 1a, the toner layer thickness is regulated to a desired value. Further, the toner T that has passed through the layer thickness regulating portion forms a brush A. Further, among the toners that form the ears A when passing through the layer thickness regulating portion, the toners that may come into contact with the developing sleeve 1a, the magnetic blade 2 and the like acquire a charging charge by frictional charging.

Therefore, in the brush A after passing through the developer regulating member, the triboelectrically charged toner and the non-triboelectrically charged toner are mixed. In particular, in the magnetic toner used in the present invention, in which the strength of the magnetization of the magnetic substance contained in the magnetic toner is within the above range, the repulsion between the toners due to the magnetic force against the cohesive force between the magnetic toners. Since the force is considered to be small, the ear A becomes thicker, and as a result, the ear A becomes
There are many toners that are not triboelectrically charged.

In the present invention, after the layer thickness is regulated by the developer regulating member, the electrode 5 is arranged so as to face the developing sleeve 1a, and an alternating electric field is applied between the two, whereby the ears are formed. A is vibrated between the electrodes. When the vibration is generated between the electrodes, the bristle A is released from the agglomeration, and the released toner can come into contact with the developing sleeve 1a during the vibration. Therefore, the ears B formed after passing between the electrodes are thinner than the ears A, and
The proportion of toner that is not triboelectrically charged in the ear B is also smaller than that in the ear A.

In the present invention, the gap between the developing sleeve 1a and the electrode 5 is about 300 μm, and the gap between the developing sleeve 1a and the developer regulating member 2 is about 30 μm.
It was set to 0 μm. In the configuration of the present invention, the power source 4
To apply a developing bias to the developing sleeve 1a, and the developing bias is Vpp 1,800V,
An AC rectangular wave bias having a frequency of 2,000 Hz is used. Therefore, in the present invention, an alternating electric field equivalent to the developing bias is applied between the electrodes by grounding the electrodes 5.

The magnetic toner used in the present invention has a structure in which the magnetic strength of the magnetic toner is reduced without reducing the amount of magnetic material in the magnetic toner. That is, the strength of magnetization in a magnetic field of 1 KOe was set to 10 to 40 emu / g. In general,
A magnetic material having a smaller intensity of magnetization than a magnetic material that is normally used is used. Examples of the magnetic substance contained in the toner include metal oxides containing elements such as iron, cobalt, nickel, copper, magnesium, manganese, aluminum and silicon. The magnetic substance used in the examples of the magnetic toner of the present invention is spinel-type iron oxide obtained by the synthesis method as shown below.

(Synthesis Example) As a reactor, a bubble oxidation type reaction column having an internal capacity of 180 liters was used. Industrial iron sulfate is dissolved in water to prepare 40 liters of a solution having a ferrous iron concentration of 134 g / liter. Separately, 40 liters of a solution having a caustic soda concentration of 182 g / liter was prepared, and the above iron sulfate solution was added thereto with stirring to neutralize the solution so that the residual caustic soda became 5 g / liter. To this was added 50 liters of an industrial zinc hydroxide solution having a pH of 11.3 and a zinc concentration of 40 g / liter to prepare a reaction solution having a ferrous iron concentration of 40 g / liter. While maintaining the temperature of the reaction solution at 80 ° C., the oxidizing air was supplied at 10 liter / min. Was blown in at a ratio of, and an oxidation reaction was carried out. The reaction was completed in about 7 hours. Next, this slurry was washed and dried to obtain spinel type iron oxide. The obtained magnetic material has a horizontal ferret diameter of 0.25.
μm, BET 8.8 m ² / g, magnetization strength 31.5 em
u / g, coercive force 170 Oe, remanent magnetization 5.7 emu / g
Met.

The magnetic toner was prepared as follows. Styrene-acrylic copolymer 54.9% by weight Negative charge control agent 0.5% by weight Magnetic substance (magnetic substance obtained in the above synthesis example) 44.4% by weight Release agent 0.2% by weight powder After mixing, the mixture was heat-kneaded with a two-roll mill set at 140 ° C. for about 30 minutes, cooled, and then coarsely pulverized and finely pulverized (jet mill). Further, fine powder and coarse powder were cut by an elbow jet classifier to obtain a toner composition. The particle size of the obtained toner was 8.5 μm in weight average diameter and the coefficient of change was 30%. 0.6% by weight of negatively chargeable colloidal silica was externally added to this to obtain a developer.

The magnetic material used in the present invention is not limited to this embodiment, the magnetization intensity in a magnetic field of 1 KOe is 10 to 40 emu / g, and the horizontal ferret diameter is 0.05 μm.
Any magnetic material having a size of m to 0.5 μm may be used. The developer regulating member used in the present invention is not limited to the above-mentioned embodiment, and for example, as shown in FIG. 5, the toner layer thickness is regulated by a non-magnetic elastic blade 21 such as urethane rubber. You can also use it.

Further, the method of applying an alternating electric field between the developing sleeve 1a and the counter electrode 5 used in the present invention is not limited to the constitution of the present invention. For example, as shown in FIG. The power source 41 may be provided. Further, the Vpp and frequency of the alternating voltage applied between the opposed electrodes used in the present invention are not limited to those in this embodiment, and the ears formed by the magnetic toner respond to the electric field a plurality of times between the electrodes. It vibrates, and the voltage does not leak between the electrodes, that is, in the range of 100V to 3,000V, preferably 500V to 2,500V.
Further, the DC bias voltage may be superposed, and the range of the superposed DC voltage may be 1,000 V or less in absolute value. With the above configuration, it is possible to reduce the strength of magnetization of the magnetic toner without reducing the amount of the magnetic material in the magnetic toner, and to stabilize the process of applying the electric charge to the magnetic toner, which results in good image reproducibility. It has become possible to do so.

Example 2 The present invention is not limited to the magnetic toner of Example 1 above. A magnetic substance was produced in the same manner as in the synthesis example of Example 1 to obtain spinel iron oxide. The obtained magnetic material had a horizontal ferret diameter of 0.20 μm and BET9. m ² / g, strength of magnetization 37.8 emu / g, coercive force 78 Oe, remanent magnetization 6.4
It was emu / g. A toner was produced using this magnetic material. The prescription is as follows. Styrene-acrylic copolymer 49.7% by weight Negative charge control agent 0.5% by weight Magnetic material (magnetic material) 49.6% by weight Release agent 0.2% by weight Obtained toner has a weight average particle diameter 6.1 μm, change coefficient 34
%Met. Negatively charged colloidal silica is added to this 0.9
Externally added by weight% to obtain a developer. By using this magnetic toner and the developing device of Example 1, it becomes possible to stabilize the charge application to the magnetic toner and to improve the image reproducibility.

Embodiment 3 The present invention is not limited to the construction of the above embodiment, and the wire-shaped electrode 5 as shown in FIG. 2 may be used as the electrode arranged facing and close to the magnetic sleeve 1a. . Further, at this time, the number of wire electrodes arranged is not limited to one. By using the developing device of this configuration and the magnetic toner of Example 1, it is possible to stabilize the charge application to the magnetic toner and to perform image reproducibility.

Embodiment 4 The present invention is not limited to the constitution of the above-mentioned embodiment, and the arrangement position of the electrodes which are arranged close to and facing the developing sleeve 1a is the developer regulating member 2 as shown in FIG. The developing sleeve 1a may be arranged not only on the upstream side in the rotation direction but also on the downstream side. By using the developing device of this configuration and the magnetic toner of Example 1, it is possible to stabilize the charge application to the magnetic toner and to improve the image reproducibility.

(Second Invention) One embodiment according to the present invention will be described below with reference to the drawings. FIG. 7 is a sectional view of a developing device which is an embodiment of the present invention. In the figure, 1a is a sleeve made of a non-magnetic metal, which is a developer carrier that rotates in the direction of the arrow, 1b is a permanent magnet disposed inside the developing sleeve 1a, and 2 is a developer carrier composed of a magnetic member. A magnetic blade 9 for controlling the amount of the upper developer, a developing device 9 and a carrying member 3 for carrying the magnetic toner in the developing device 9 toward the sleeve 1a. Reference numeral 5 denotes an electrode, which is a feature of the present invention, and is arranged in close proximity to the developing sleeve 1a.
At least the surface facing the developing sleeve 1a is covered with an acrylic resin 6 which is electrically insulating and has a charging polarity different from that of the magnetic toner having a negative polarity used in the present invention. In the present invention, the acrylic resin is coated by the dipping method so as to have a thickness of about 25 μm. Reference numeral 4 is a power source for applying a developing bias to the developing sleeve.

According to the developing device having the above-mentioned structure, FIG.
As shown in FIG. 4, the magnetic toner T in the developing container 9 is conveyed in the direction of the arrow on the developing sleeve 1a, and when the magnetic toner T passes through the gap between the developer regulating member 2 and the developing sleeve 1a, Regulated by toner layer thickness. Further, the toner T that has passed through the layer thickness regulating portion forms a brush A. Further, among the toners that form the ears A when passing through the layer thickness regulating portion, the toners that may come into contact with the developing sleeve 1a, the magnetic blade 2 and the like acquire a charging charge by frictional charging. Therefore, in the brush A after passing through the developer regulating member, the triboelectrically charged toner and the non-triboelectrically charged toner are mixed. In particular, in the magnetic toner used in the present invention, in which the strength of the magnetization of the magnetic substance contained in the magnetic toner is within the above range, the repulsion between the toners due to the magnetic force against the cohesive force between the magnetic toners. Since the force is considered to be small, the ears A become thick, and as a result, a large amount of toner that is not triboelectrically charged exists in the ears A.

In the present invention, the electrode 5 is provided so as to face the developing sleeve 1a after the layer thickness is regulated by the developer regulating member, and at least the electrode 5 faces the developing sleeve 1a. By setting the surface to be covered with the insulating member 6 and applying an alternating electric field between them,
The ear A is vibrated between the electrodes. The ear A is
Agglomeration is released during vibration between the electrodes, and the released toner can come into contact with the developing sleeve 1a during the vibration, and also comes into contact with the counter electrode 5.

In the present invention, the surface of the counter electrode 5 facing the developing sleeve 1a is covered with a member 6 having a charging polarity different from that of the magnetic toner used in the present invention. Therefore, the magnetic toner from which the agglomeration of the upper air spikes A has been released is contacted with the developing sleeve 1a and also with the covering member 6 when vibrating between the electrodes.
It becomes possible to obtain a triboelectric charge.

Therefore, the ears B formed after passing between the electrodes
Is smaller than that in the ear A, and the proportion of toner that is not triboelectrically charged in the ear B is smaller than that in the ear A. Further, in the present invention, another characteristic of the covering member 6 is a member exhibiting an insulating property. Therefore, since the surface of the electrode 5 facing the developing sleeve 1a is covered with the insulating member 6, the alternating electric field does not leak even under high humidity, and the same effect can be obtained. . In the present invention, the gap between the developing sleeve 1a and the electrode 5 is about 300 μm, and the gap between the developing sleeve 1a and the developer regulating member 2 is about 300 μm.
And

Further, in the constitution of the present invention, the developing bias is applied to the developing sleeve 1a by the power source 4, and the developing bias is an AC rectangular wave bias having a Vpp of 1,800 V and a frequency of 2,000 Hz. There is.
Therefore, in the present invention, an alternating electric field equivalent to the developing bias is applied between the electrodes by grounding the electrodes 5.

The magnetic toner used in the present invention has a structure in which the strength of magnetization of the magnetic toner is reduced without reducing the amount of magnetic material in the magnetic toner. That is, the strength of magnetization in a magnetic field of 1 KOe was set to 10 to 40 emu / g. In general,
A magnetic material having a smaller intensity of magnetization than a magnetic material that is normally used is used. Examples of the magnetic substance contained in the toner include metal oxides containing elements such as iron, cobalt, nickel, copper, magnesium, manganese, aluminum and silicon. The magnetic substance used in the examples of the magnetic toner of the present invention is spinel-type iron oxide obtained by the synthesis method as shown below.

(Synthesis Example) As the reactor, a bubble oxidation type reaction column having an internal capacity of 180 liters was used. Industrial iron sulfate is dissolved in water to prepare 40 liters of a solution having a ferrous iron concentration of 134 g / liter. Separately, 40 liters of a solution having a caustic soda concentration of 182 g / liter was prepared, and the above iron sulfate solution was added thereto with stirring to neutralize the solution so that the residual caustic soda became 5 g / liter. To this was added 50 liters of an industrial zinc hydroxide solution having a pH of 11.3 and a zinc concentration of 40 g / liter to prepare a reaction solution having a ferrous iron concentration of 40 g / liter. While maintaining the temperature of the reaction solution at 80 ° C., the oxidizing air was supplied at 10 liter / min. Was blown in at a ratio of, and an oxidation reaction was carried out. The reaction was completed in about 7 hours. Next, this slurry was washed and dried to obtain spinel type iron oxide. The obtained magnetic material has a horizontal ferret diameter of 0.25.
μm, BET 8.8 m ² / g, magnetization strength 31.5 em
u / g, coercive force 170 Oe, remanent magnetization 5.7 emu / g
Met.

The magnetic toner was prepared as follows. Styrene-acrylic copolymer 54.9% by weight Negative charge control agent 0.5% by weight Magnetic substance (magnetic substance obtained in the above synthesis example) 44.4% by weight Release agent 0.2% by weight powder After mixing, the mixture was heat-kneaded with a two-roll mill set at 140 ° C. for about 30 minutes, cooled, and then coarsely pulverized and finely pulverized (jet mill). Further, fine powder and coarse powder were cut by an elbow jet classifier to obtain a toner composition. The particle size of the obtained toner was 8.5 μm in weight average diameter and the coefficient of change was 30%. 0.6% by weight of negatively chargeable colloidal silica was externally added to this to obtain a developer.

The covering member 6 used in the present invention is coated with an acrylic resin so as to have a thickness of about 25 μm by a dipping method. However, the covering member 6 of the present invention is not limited to this. For example, a polycarbonate resin having a charging polarity opposite to that of the magnetic toner may be used. Further, the covering member 6 is not limited to the above, and the magnetic toner may be a carrier {EFV200 / 30.
0 (manufactured by Nippon Iron Powder Co., Ltd.)} and the polarity of the charging charge obtained when the toner is frictionally charged and the polarity of the charging charge obtained when the toner is frictionally charged with the carrier have a polarity different from that of the magnetic toner. Then, this may be used as a covering member.

The magnetic material used in the present invention is not limited to this embodiment, the magnetization intensity in a magnetic field of 1 KOe is 10 to 40 emu / g, and the horizontal ferret diameter is 0.05 μm.
Any magnetic material having a size of m to 0.5 μm may be used. The developer regulating member used in the present invention is not limited to the above embodiment, and for example, as shown in FIG. 11, the toner layer thickness is regulated by the non-magnetic elastic blade 21 such as urethane rubber. It may be one. Further, the method of applying an alternating electric field between the developing sleeve 1a and the counter electrode 5 used in the present invention is not limited to the constitution of the present invention. For example, as shown in FIG. May be arranged.

Further, the Vpp and frequency of the alternating voltage applied between the opposed electrodes used in the present invention are not limited to those in this embodiment, and the ears formed by the magnetic toner are formed a plurality of times between the electrodes. As long as it vibrates in response to an electric field and does not cause dielectric breakdown of the covering member 6,
Further, a DC bias voltage may be superimposed depending on the case.

With the above structure, even when the time for the number of vibrations of the developer due to the alternating electric field is not sufficient for the time for the developer to pass between the counter electrode and the developer carrying member, the magnetic toner is Of the magnetic field without stabilizing the amount of magnetic substance in the magnetic toner while stabilizing the process of imparting electric charge to the toner, preventing the voltage leakage of the alternating electric field between the developer carrier and the counter electrode under high humidity, and reducing the amount of magnetic substance in the magnetic toner. By reducing the strength of magnetization of the toner, it becomes possible to stabilize the process of applying the electric charge to the magnetic toner, and it is possible to improve the image reproducibility.

Embodiment 2 The present invention is not limited to the magnetic toner of Embodiment 1 described above. A magnetic substance was produced in the same manner as in the synthesis example of Example 1 to obtain spinel iron oxide. The obtained magnetic material had a horizontal ferret diameter of 0.20 μm and BET9. m ² / g, strength of magnetization 37.8 emu / g, coercive force 78 Oe, remanent magnetization 6.4
It was emu / g. A toner was produced using this magnetic material. The prescription is as follows.

Styrene-acrylic copolymer 49.7% by weight Positive charge control agent 0.5% by weight Magnetic substance (the magnetic substance) 49.6% by weight Release agent 0.2% by weight Weight average diameter 6.1 μm, change coefficient 34
%Met. 0.9% of normal electrical colloidal silica was added to this.
Externally added by weight% to obtain a developer. When this magnetic toner and a Teflon sheet having a thickness of 25 μm and having a charging polarity different from that of the magnetic toner are used as the covering member 6, Example 1
It was possible to obtain the same effect as.

Further, the polarity of the electric charge obtained when the upper air covering member 6 was triboelectrically charged with the carrier of the upper air embodiment had a polarity different from that of the upper magnetic toner, and the thickness was 25 μm.
Even when the PET film of m was used, the same effect as in Example 1 could be obtained.

Embodiment 3 The present invention is not limited to the construction of Embodiment 1 described above, and the electrode placed in close proximity to the developing sleeve 1a is a wire-shaped electrode 5 as shown in FIG. The surface of the wire electrode may be covered with a covering member 6 having a charging polarity different from that of the magnetic toner. Further, at this time, the number of wire electrodes arranged is not limited to one. Also in this configuration, the same effect as that of the first embodiment can be obtained.

Embodiment 4 The present invention is not limited to the constitution of Embodiment 1 described above, but the surface opposite to the developing sleeve 1a, which is arranged close to and facing the developing sleeve 1a, has a charging polarity different from that of the magnetic toner. As shown in FIG. 9, the arrangement position of the counter electrode 5 covered with the covering member 6 is the developing sleeve 1 of the developer regulating member 2.
The configuration may be arranged not only on the upstream side in the rotation direction of a but also on the downstream side. Also in this configuration, the same effect as that of the first embodiment can be obtained.

(Third Invention) Embodiment 1 An embodiment according to the present invention will be described below with reference to the drawings. FIG. 13 is a sectional view of a developing device which is an embodiment of the present invention. In the figure, 1a is a sleeve made of a non-magnetic metal, which is a developer carrier that rotates in the direction of the arrow, 1b is a permanent magnet disposed inside the developing sleeve 1a, and 2 is a developer carrier composed of a magnetic member. A magnetic blade 9 for controlling the amount of the upper developer, a developing device 9 and a carrying member 3 for carrying the magnetic toner in the developing device 9 toward the sleeve 1a. Reference numeral 5 denotes an electrode, which is a feature of the present invention, and is arranged to face the developing sleeve 1a so as to face the developing sleeve 1a.
The surface opposite to is covered with an insulating member 6.

In the present invention, a PET film having a thickness of 25 μm was used as the covering member. Reference numeral 4 is a power source for applying a developing bias to the developing sleeve. According to the developing device having the above-described configuration, as shown in FIG. 14, the magnetic toner T in the developing container 9 is conveyed on the developing sleeve 1a in the arrow direction, and the developer regulating member 2 and the developing member 2 When passing through the gap of the sleeve 1a, it is regulated to a desired toner layer thickness. Further, the toner T that has passed through the layer thickness regulating portion is
Form ears A.

When passing through the layer thickness regulating portion, the ears A
Of the toner forming the toner, the toner that can come into contact with the developing sleeve 1a, the magnetic blade 2 and the like obtains a charged electric charge by frictional charging. Therefore, in the brush A after passing through the developer regulating member, the triboelectrically charged toner and the non-triboelectrically charged toner are mixed. In particular, in the magnetic toner used in the present invention, in which the strength of the magnetization of the magnetic substance contained in the magnetic toner is within the above range, the repulsion between the toners due to the magnetic force against the cohesive force between the magnetic toners. Since the force is considered to be small, the ears A become thick, and as a result, a large amount of toner that is not triboelectrically charged exists in the ears A.

In the present invention, after the toner layer thickness is regulated by the developer regulating member, the electrode 5 is provided so as to face the developing sleeve 1a, and at least the electrode 5 faces the developing sleeve 1a. The surface in which the ears A are covered is covered with an insulating member 6, and an alternating electric field is applied between the two to vibrate the ears A between the electrodes. The ears A are deaggregated during the vibration between the electrodes, and the unraveled toner can come into contact with the developing sleeve 1a during the vibration. Therefore, the ears B formed after passing between the electrodes are thinner than the ears A, and the proportion of toner that is not frictionally charged in the ears B is smaller than that in the ears A.

Since the surface of the electrode 5 facing the developing sleeve 1a is covered with the insulating member 6, the alternating electric field does not leak even under high humidity, and the same effect can be obtained. You can get it. In the present invention, the gap between the developing sleeve 1a and the electrode 5 is about 300 μm, and the gap between the developing sleeve 1a and the developer regulating member 2 is about 300 μm. Further, in the structure of the present invention, the developing bias is applied to the developing sleeve 1a by the power source 4, and the developing bias is Vpp.
The AC rectangular wave bias has a voltage of 1800 V and a frequency of 2,000 Hz.

Therefore, in the present invention, by grounding the electrode 5, an alternating electric field equivalent to the developing bias can be obtained.
A voltage is applied between the electrodes. The magnetic toner used in the present invention is configured to reduce the strength of magnetization of the magnetic toner without reducing the amount of magnetic material in the magnetic toner. That is, the strength of magnetization in a magnetic field of 1 KOe was set to 10 to 40 emu / g. In general, a magnetic substance having a smaller magnetization intensity than a normally used magnetic substance is used. Examples of the magnetic substance contained in the toner include metal oxides containing elements such as iron, cobalt, nickel, copper, magnesium, manganese, aluminum and silicon. The magnetic substance used in the examples of the magnetic toner of the present invention is spinel-type iron oxide obtained by the synthesis method as shown below.

(Synthesis Example) As a reactor, a bubble oxidation type reaction column having an internal capacity of 180 liters was used. Industrial iron sulfate is dissolved in water to prepare 40 liters of a solution having a ferrous iron concentration of 134 g / liter. Separately, 40 liters of a solution having a caustic soda concentration of 182 g / liter was prepared, and the above iron sulfate solution was added thereto with stirring to neutralize the solution so that the residual caustic soda became 5 g / liter. To this was added 50 liters of an industrial zinc hydroxide solution having a pH of 11.3 and a zinc concentration of 40 g / liter to prepare a reaction solution having a ferrous iron concentration of 40 g / liter. While maintaining the temperature of the reaction solution at 80 ° C., the oxidizing air was supplied at 10 liter / min. Was blown in at a ratio of, and an oxidation reaction was carried out. The reaction was completed in about 7 hours. Next, this slurry was washed and dried to obtain spinel type iron oxide. The obtained magnetic material has a horizontal ferret diameter of 0.25.
μm, BET 8.8 m ² / g, magnetization strength 31.5 em
u / g, coercive force 170 Oe, remanent magnetization 5.7 emu / g
Met.

The magnetic toner was prepared as follows. Styrene-acrylic copolymer 54.9% by weight Negative charge control agent 0.5% by weight Magnetic substance (magnetic substance obtained in the above synthesis example) 44.4% by weight Release agent 0.2% by weight powder After mixing, the mixture was heat-kneaded with a two-roll mill set at 140 ° C. for about 30 minutes, cooled, and then coarsely pulverized and finely pulverized (jet mill). Further, fine powder and coarse powder were cut by an elbow jet classifier to obtain a toner composition. The particle size of the obtained toner was 8.5 μm in weight average diameter and the coefficient of change was 30%. 0.6% by weight of negatively chargeable colloidal silica was externally added to this to obtain a developer.

The insulating coating member used in the present invention is a PET film having a thickness of 25 μm, but the present invention is not limited to this, and a Teflon sheet or the like may be used.
Further, an acrylic resin, a fluorine-containing resin or the like may be coated on the electrode 5 by a dipping method or the like.

The covering member 6 used in the present invention is coated with an acrylic resin by a dipping method so as to have a thickness of about 25 μm. However, the covering member 6 of the present invention is not limited to this. For example, a polycarbonate resin having a charging polarity opposite to that of the magnetic toner may be used. Further, the covering member 6 is not limited to the above, and the magnetic toner may be a carrier {EFV200 / 30.
0 (manufactured by Nippon Iron Powder Co., Ltd.)} and the polarity of the charging charge obtained when the toner is frictionally charged and the polarity of the charging charge obtained when the toner is frictionally charged with the carrier have a polarity different from that of the magnetic toner. Then, this may be used as a covering member.

The magnetic material used in the present invention is not limited to this embodiment, the magnetization intensity in a magnetic field of 1 KOe is 10 to 40 emu / g, and the horizontal ferret diameter is 0.05 μm.
Any magnetic material having a size of m to 0.5 μm may be used. The developer regulating member used in the present invention is not limited to the above-described embodiment, and for example, as shown in FIG. 17, the toner layer thickness is regulated by a non-magnetic elastic blade 21 such as urethane rubber. It may be one. Further, the method of applying an alternating electric field between the developing sleeve 1a and the counter electrode 5 used in the present invention is not limited to the constitution of the present invention. For example, as shown in FIG. May be arranged.

Further, the Vpp and frequency of the alternating voltage applied between the opposed electrodes used in the present invention are not limited to those in this embodiment, and the ears formed by the magnetic toner are formed a plurality of times between the electrodes. As long as it vibrates in response to an electric field and does not cause dielectric breakdown of the insulating member 6,
Further, a DC bias voltage may be superimposed depending on the case.
With the above structure, the voltage leakage of the alternating electric field between the developer carrying member and the counter electrode under high humidity is prevented, and the strength of the magnetization of the magnetic toner is reduced without reducing the amount of the magnetic substance in the magnetic toner. It is possible to reduce the charge density and to stabilize the process of applying the electric charge to the magnetic toner, thereby improving the image reproducibility.

Example 2 The present invention is not limited to the magnetic toner of Example 1 above. A magnetic substance was produced in the same manner as in the synthesis example of Example 1 to obtain spinel iron oxide. The obtained magnetic material had a horizontal ferret diameter of 0.20 μm and BET9. m ² / g, strength of magnetization 37.8 emu / g, coercive force 78 Oe, remanent magnetization 6.4
It was emu / g. A toner was produced using this magnetic material. The prescription is as follows. Styrene-acrylic copolymer 49.7% by weight Negative charge control agent 0.5% by weight Magnetic substance (the magnetic substance) 49.6% by weight Release agent 0.2% by weight

The obtained toner has a weight average diameter of 6.1 μm,
The change coefficient was 34%. 0.9% by weight of negatively chargeable colloidal silica was externally added to the mixture to prepare a developer. When this magnetic toner and the developing device of Example 1 were used, voltage leakage of an alternating electric field between the developer carrier and the counter electrode under high humidity was prevented, and the magnetic substance in the magnetic toner was prevented. Since the magnetic strength of the magnetic toner can be reduced and the charge can be stably applied to the magnetic toner without decreasing the amount, it is possible to improve the image reproducibility. became.

Embodiment 3 The present invention is not limited to the construction of Embodiment 1 described above, and the electrodes arranged in the vicinity of the developing sleeve 1a facing each other are shown in FIG.
It is also possible to use a wire-shaped electrode 5 as shown in and to cover the surface of the wire electrode with an insulating member 6. Further, at this time, the number of wire electrodes arranged is not limited to one. By using the developing device of this configuration and the magnetic toner of Example 1, it is possible to prevent voltage leakage of an alternating electric field between the developer carrier and the counter electrode under high humidity, and Since it is possible to reduce the magnetic strength of the magnetic toner without reducing the amount of the magnetic material and to stabilize the charge application to the magnetic toner, it is possible to quantify the image reproducibility. became.

Embodiment 4 The present invention is not limited to the constitution of the above-mentioned embodiment, but is opposed to the developing sleeve 1a and is opposed to the developing sleeve 1a. The opposed surface of the opposed surface of the developing sleeve 1a is covered with the insulating member 6. As shown in FIG. 15, the arrangement position may be arranged not only on the upstream side of the developer regulating member 2 in the rotation direction of the developing sleeve 1a but also on the downstream side thereof. By using the developing device of this configuration and the magnetic toner of Example 1, it is possible to prevent voltage leakage of an alternating electric field between the developer carrier and the counter electrode under high humidity, and Since it is possible to reduce the magnetic strength of the magnetic toner without reducing the amount of magnetic material and to stabilize the charge application to the magnetic toner, it is possible to improve the image reproducibility. It became like.

[0164] (Fourth invention) Example 1 Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. FIG. 19A is a sectional view of a developing device which is an embodiment of the present invention. In the figure, reference numeral 1a is a developer carrying member (in the following, a non-magnetic metal developing sleeve is shown) which rotates in the direction of the arrow. Reference numeral 2 is a regulating member (hereinafter referred to as a magnetic blade) for regulating the amount of developer on the developing sleeve. In the present invention, as shown in FIG. 19A, the permanent magnet 1b contained in the developing sleeve 1a is included. It faces the vicinity of the magnetic pole position. Further, the distance between the magnetic blade and the developing sleeve is 1 mm or less, and the width of the magnetic blade is narrower than the width of the magnetic pole of the permanent magnet 1b facing the magnetic blade. A vibrating member 4 is arranged near the magnetic blade.

The vibrating member 4 has one end connected to the vibration transmitter 5 and the other end fixed to the developing container 9.
The vibrating member 4 may be of any shape, such as wire, plate, brush, mesh, comb, etc., as long as the vibration from the vibration transmitter is transmitted. The vibration transmitter 5 may be any of commonly used ultrasonic vibrators, vibration members using an alternating electric field, vibration members using a magnetic field, and the like. A conveying member 3 conveys the toner in the developing container 9 to the developing sleeve. In this configuration, the toner is packed behind the magnetic blade 2 so that the developer can be quickly and densely supplied to the developing section.

In the magnetic toner used in the present invention, in order to reduce the magnetic strength of the magnetic toner without reducing the amount of magnetic substance in the magnetic toner, the magnetic field 1 having a weaker magnetic strength than usual is used.
It contains a magnetic material having a magnetization intensity in KOe of 10 to 40 emu / g. Examples of the magnetic substance contained in the toner include metal oxides containing elements such as iron, cobalt, nickel, copper, magnesium, manganese, aluminum and silicon. The magnetic substance used in the examples of the magnetic toner of the present invention is spinel-type iron oxide obtained by the synthesis method as shown below.

(Synthesis Example) As a reactor, a bubble oxidation type reaction column having an internal capacity of 180 liters was used. Industrial iron sulfate is dissolved in water to prepare 40 liters of a solution having a ferrous iron concentration of 134 g / liter. Separately, 40 liters of a solution having a caustic soda concentration of 182 g / liter was prepared, and the above iron sulfate solution was added thereto with stirring to neutralize the solution so that the residual caustic soda became 5 g / liter. To this was added 50 liters of an industrial zinc hydroxide solution having a pH of 11.3 and a zinc concentration of 40 g / liter to prepare a reaction solution having a ferrous iron concentration of 40 g / liter. While maintaining the temperature of the reaction solution at 80 ° C., the oxidizing air was supplied at 10 liter / min. Was blown in at a ratio of, and an oxidation reaction was carried out. The reaction was completed in about 7 hours. Next, this slurry was washed and dried to obtain spinel type iron oxide. The obtained magnetic material has a horizontal ferret diameter of 0.25.
μm, BET 8.8 m ² / g, magnetization strength 31.5 em
u / g, coercive force 170 Oe, remanent magnetization 5.7 emu / g
Met.

The magnetic toner was prepared as follows. Styrene-acrylic copolymer 54.9% by weight Negative charge control agent 0.5% by weight Magnetic substance (magnetic substance obtained in the above synthesis example) 44.4% by weight Release agent 0.2% by weight powder After mixing, the mixture was heat-kneaded with a two-roll mill set at 140 ° C. for about 30 minutes, cooled, and then coarsely pulverized and finely pulverized (jet mill). Further, fine powder and coarse powder were cut by an elbow jet classifier to obtain a toner composition. The particle size of the obtained toner was 8.5 μm in weight average diameter and the coefficient of change was 30%. 0.6% by weight of negatively chargeable colloidal silica was externally added to this to obtain a developer.

The Applicant conducted the following study on the charging property of the toner. That is, as shown in FIG. 19B, the magnetic blade 2 facing the vicinity of the magnetic pole position of the permanent magnet 1b contained in the developing sleeve 1a, and the wire-shaped vibrating member 4 arranged in the vicinity thereof. And a vibration transmitter 5 to which the vibration member 4 is connected. The toner of the present invention was put in this and the chargeability was examined. As a result, in the developing device as shown in FIG. 19 (b), the toner of the present invention had good chargeability.

This is because the vibration is transmitted from the vibration transmitter 5 to the wire-shaped vibrating member 4, and the wire member 4 is provided in the vicinity of the magnetic blade 2 in the toner container 9 filled with toner.
It is considered that, since the toner vibrates in the packed toner to loosen the aggregation of the toner, and then passes through the magnetic blade 2, it is possible to obtain good charge impartment.

As a result, with the above construction, when the magnetic toner has a magnetization strength within the above range, the image reproducibility can be improved without causing fog in the background portion. The magnetic material used in the present invention is not limited to this example, and the strength of magnetization in a magnetic field of 1 KOe is 10 to 10.
40 emu / g, horizontal ferret diameter is 0.05 μm ~
Any magnetic substance having a thickness of 0.5 μm may be used. One example is shown in Example 2.

Embodiment 2 The present invention is not limited to the magnetic toner of Embodiment 1 described above. A magnetic substance was produced in the same manner as in the synthesis example of Example 1 to obtain spinel iron oxide. The obtained magnetic material had a horizontal ferret diameter of 0.20 μm and BET9. m ² / g, strength of magnetization 37.8 emu / g, coercive force 78 Oe, remanent magnetization 6.4
It was emu / g. A toner was produced using this magnetic material. The prescription is as follows. Styrene-acrylic copolymer 49.7% by weight Negative charge control agent 0.5% by weight Magnetic material (magnetic material) 49.6% by weight Release agent 0.2% by weight Obtained toner has a weight average particle diameter 6.1 μm, change coefficient 34
%Met. 0.9% by weight of negatively chargeable silica was added to this to obtain a developer. Using this magnetic toner, Example 1
When charged in the developing device of No. 3, the chargeability of the toner was stabilized. As a result, it has become possible to improve the image reproducibility.

Third Embodiment The present invention is not limited to the configuration of the above-mentioned embodiment, and the vibrating member 4 disposed in the vicinity of the toner layer restricting member is shown in FIG.
20, the member of Example 1 is used as the ultrasonic vibrator and the brush-shaped vibrating member 4 is bonded to the ultrasonic vibrator as shown in FIG. 20. In all the magnetic toners, when the magnetization intensity of the magnetic toner was within the above range, the chargeability of the magnetic toner could be stabilized. As a result, it has become possible to improve the image reproducibility.

Embodiment 4 The present invention is not limited to the constitution of the above-mentioned embodiment, and an oscillating member arranged near the magnetic blade 2 for regulating the amount of developer on the developer carrying member is provided upstream of the magnetic blade. 21B, a vibration transmitter 5 by an alternating electric field is attached to the vibration member 4 as shown in FIG. An alternating electric field (frequency of 4,000 Hz) is applied to this vibration transmitter 5,
It was made to vibrate. As a result, in all of the magnetic one-component toners of Example 1, when the magnetization intensity of the magnetic toner is within the above range, the chargeability of the magnetic toner can be further stabilized, and the magnetic toner can also be charged. As a result, the image reproducibility can be further improved. The arrangement of the vibrating member, the arrangement of the vibration transmitter, etc. are not limited to all the above-mentioned embodiments, but it is preferable to appropriately select the arrangement position according to the developing device configuration.

(Fifth Invention) One embodiment according to the present invention will be described below with reference to the drawings. FIG. 22 (a) shows
FIG. 3 is a cross-sectional view of a developing device that is an embodiment of the present invention. In the figure, reference numeral 1a is a developer carrying member (in the following, a non-magnetic metal developing sleeve is shown) which rotates in the direction of the arrow. An elastic blade used as an elastic member for regulating the amount of developer on the developer carrying member, which is one of the features of the present invention. In the present invention, as shown in FIG. 1a
The elastic blade 2 is contacted in the counter direction with respect to the rotation direction of. 1b is a permanent magnet, as shown in FIG.
As shown in (a), it is arranged in the developing sleeve 1a. The elastic blade 2 is a rubber having an appropriate elastic modulus,
For a blade made of plastic or the like, the pressure at the contact point is set by displacing the blade as shown in FIG. 22 (a) to uniformly apply pressure to the contact generatrix area, or a rotary shaft utilizing the lever principle. It may be applied by a method of applying a constant pressure with one end centered at, or a so-called equalize uniform load method fixed to the developing device frame. Further, the thickness of the elastic body regulating member is preferably 2 mm or less.

In the magnetic toner used in the present invention, in order to reduce the magnetic strength of the magnetic toner without reducing the amount of magnetic substance in the magnetic toner, the magnetic field 1 having a weaker magnetic strength than usual is used.
It contains a magnetic material having a magnetization intensity in KOe of 10 to 40 emu / g. Examples of the magnetic substance contained in the toner include metal oxides containing elements such as iron, cobalt, nickel, copper, magnesium, manganese, aluminum and silicon. The magnetic substance used in the examples of the magnetic toner of the present invention is spinel-type iron oxide obtained by the synthesis method as shown below.

(Synthesis Example) As the reactor, a bubble oxidation type reaction column having an internal capacity of 180 liters was used. Industrial iron sulfate is dissolved in water to prepare 40 liters of a solution having a ferrous iron concentration of 134 g / liter. Separately, 40 liters of a solution having a caustic soda concentration of 182 g / liter was prepared, and the above iron sulfate solution was added thereto with stirring to neutralize the solution so that the residual caustic soda became 5 g / liter. To this was added 50 liters of an industrial zinc hydroxide solution having a pH of 11.3 and a zinc concentration of 40 g / liter to prepare a reaction solution having a ferrous iron concentration of 40 g / liter. While maintaining the temperature of the reaction solution at 80 ° C., the oxidizing air was supplied at 10 liter / min. Was blown in at a ratio of, and an oxidation reaction was carried out. The reaction was completed in about 7 hours. Next, this slurry was washed and dried to obtain spinel type iron oxide. The obtained magnetic material has a horizontal ferret diameter of 0.25.
μm, BET 8.8 m ² / g, magnetization strength 31.5 em
u / g, coercive force 170 Oe, remanent magnetization 5.7 emu / g
Met.

The magnetic toner was prepared as follows. Styrene-acrylic copolymer 54.9% by weight Negative charge control agent 0.5% by weight Magnetic substance (magnetic substance obtained in the above synthesis example) 44.4% by weight Release agent 0.2% by weight powder After mixing, the mixture was heat-kneaded with a two-roll mill set at 140 ° C. for about 30 minutes, cooled, and then coarsely pulverized and finely pulverized (jet mill). Further, fine powder and coarse powder were cut by an elbow jet classifier to obtain a toner composition. The particle size of the obtained toner was 8.5 μm in weight average diameter and the coefficient of change was 30%. 0.6% by weight of negatively chargeable colloidal silica was externally added to this to obtain a developer.

The present applicant conducted the following study on the state of the ears of the toner. That is, the developing device as shown in FIG. 22B, that is, the urethane rubber elastic blade 2 having a thickness of 1 mm is brought into contact with the rotating direction of the developing sleeve 1 in the counter direction to develop the magnetic toner. The elastic blade is strongly pressed against the sleeve, the contact point of the elastic blade is at a position facing the vicinity of the pole of the magnet 1b, and the aluminum electrode member 5 is arranged on the back surface of the elastic blade. The blade 2 and the developing sleeve 1 are arranged from the contact point to the downstream side.

A rectangular alternating electric field (Vpp 2,000 V, frequency 2,000 H) is provided between the electrode member 5 and the developing sleeve 1.
The toner of the present invention was placed in a developing device to which z) was applied, and the state of ears was observed. As the condition of the alternating electric field used in this configuration, the applied voltage is preferably 100V to 5KV,
The frequency is preferably 1 KHz to 5 KHz. The waveform may be a rectangular wave or a sine wave, but it is preferable to use a rectangular wave having a high effective value. Further, the toner of the present invention was placed in a developing device from which the electrode member 5 was removed, and the state of the ears of the toner was observed. As a result, in the developing device as shown in FIG. 22 (b), the state of the ears of the toner of the present invention was loose and dense. Further, in the developing device of FIG. 22B from which the electrode member 5 is removed, the state of the ears of the toner of the present invention is dense, but the ears are thick.

This is because the formation of the spikes of toner in the developing unit
Since the strength of the magnetization of the magnetic toner and the magnetic attraction force with the magnet 1b depend on the magnetic strength of the toner of the present invention,
Since the attractive force in the magnetic field direction is small and the repulsive force in the direction perpendicular to the magnetic field direction is small, the spikes become short and thick, and when the developing device shown in FIG. After the toner layer is regulated, it is considered that the toner is conveyed to the developing unit in the state of the ears as it is. Therefore, the present applicant is
As shown in (a), the elastic blade 2 is contacted in the counter direction with respect to the rotation direction of the developing sleeve 1a,
Further, the contact point of the elastic blade is located at a position facing one pole vicinity of the magnet 1b, and an electrode member 5 is arranged on the back surface of the elastic blade. The electrode member 5 is composed of the elastic blade 2 and the developing sleeve 1. The power supply 4 applies a rectangular alternating electric field (Vpp 2,000 V, frequency 2,000 Hz) between the electrode member 5 and the developing sleeve 1 so as to be arranged downstream from the contact. It is considered that, as a result, the ears of the toner fly by the electric field, vibrate between the elastic blade and the developing sleeve, and the ears are gradually loosened and rearranged as they are conveyed downstream.

Therefore, even when the ears are aggregated, when the above-mentioned constitution of the present invention is adopted, the state of the ears of the above-mentioned toner of the present invention is always disentangled even if the ears after the toner layer is regulated are short and thick, and the charging property is stable. I was in a state. As a result, with the above configuration, when the magnetization intensity of the magnetic toner is within the above range, the image reproducibility can be improved without causing fog in the background portion. The magnetic substance used in the present invention is not limited to this example, and is a magnetic substance having a magnetization intensity of 10 to 40 emu / g in a magnetic field of 1 KOe and a horizontal ferret diameter of 0.05 μm to 0.5 μm. I wish I had it. One example is shown in Example 2.

Embodiment 2 The present invention is not limited to the configuration of Embodiment 1 described above. A magnetic substance was produced in the same manner as in the synthesis example of Example 1 to obtain spinel iron oxide. The obtained magnetic material had a horizontal ferret diameter of 0.20 μm and BET9. m ² / g, strength of magnetization 37.
8 emu / g, coercive force 78 Oe, remanent magnetization 6.4 emu
/ G. A toner was produced using this magnetic material. The prescription is as follows.

Styrene-acrylic copolymer 49.7% by weight Negative charge control agent 0.5% by weight Magnetic material (magnetic material) 49.6% by weight Release agent 0.2% by weight Weight average diameter 6.1 μm, change coefficient 34
%Met. 0.9% by weight of negatively chargeable silica was added to this to obtain a developer. When this toner was used and put in the developing unit of Example 1, the ears of the toner were short and were in a loosened state, and the charging property was stabilized. As a result, it has become possible to improve the image reproducibility.

Embodiment 3 The present invention is not limited to the construction of the above-mentioned embodiment, and the elastic body regulating member for regulating the amount of the developer on the developer carrying member is the elastic body blade 2 as shown in FIG. The electrode member 5 is arranged on the back surface of the elastic blade, and the electrode member 5 is arranged from the contact point between the elastic blade 2 and the developing sleeve 1 to the downstream side. An alternating electric field (Vpp 2,000 V, frequency 2,000 Hz) between the electrode member 5 and the developing sleeve 1.
Is applied by the power source 4. In the present invention, all the magnetic toners of Example 1 are constituted by using the member of Example 1 as the elastic blade and bringing the elastic blade into contact with the direction of rotation of the developing sleeve in the forward direction as shown in FIG. In the above, when the magnetization intensity of the magnetic toner was within the above range, the ears of the magnetic toner were in a loosened state, and the chargeability could be stabilized. As a result, it has become possible to improve the image reproducibility.

Embodiment 4 The present invention is not limited to the constitution of the above embodiment, and the elastic body regulating member for regulating the amount of the developer on the developer carrying member is the elastic body roller 2 as shown in FIG. An electrode member 5 is arranged inside the elastic roller, and an alternating electric field (Vpp 2,000) is provided between the electrode member 5 and the developing sleeve 1.
V, frequency 2,000 Hz) was applied by the power supply 4. The elastic roller may be used in contact with the developing sleeve. In the present invention, urethane is used as the elastic roller, and by rotating the elastic roller in the direction of the arrow in FIG. 24, in all the magnetic one-component toners of Example 1, the strength of magnetization of the magnetic toner falls within the above range. In the inside, the ears of the magnetic toner were in a loosened state, and the chargeability could be stabilized. As a result, it has become possible to improve the image reproducibility. The arrangement of the elastic members, the arrangement of the electrodes, the arrangement of the power source, etc. are not limited to all of the above-mentioned embodiments, and it is preferable to appropriately select the arrangement position depending on the construction of the developing device.

[0187] (Sixth invention) Example 1 Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. FIG. 25 is a sectional view of a developing device which is an embodiment of the present invention. In the figure, reference numeral 1a denotes a developer carrying member that rotates in the direction of the arrow (a non-magnetic metal developing sleeve is shown as an example below)
Is. Reference numeral 2 is a toner layer regulating member (hereinafter, a magnetic blade is shown as an example) that regulates the amount of developer on the developing sleeve. In the present invention, as shown in FIG.
It faces the vicinity of the magnetic pole position of the permanent magnet 1b included in. Further, the distance between the magnetic blade and the developing sleeve is 1 mm or less, and the width of the magnetic blade is narrower than the width of the magnetic pole of the permanent magnet 1b facing the magnetic blade.

Reference numeral 4 is a lattice member, which is arranged near the magnetic blade. The grid member 4 is fixed to the developing container 9 and is in contact with the developing sleeve. or,
The grid-like member 4 may be of any shape, such as a wire mesh shape or a plate shape with open eyes in a grid shape. The length of one side of the opening is preferably 100 μm or less. is there. A conveying member 3 conveys the toner in the developing container 9 to the developing sleeve 1. In this configuration, the toner is packed on the back side of the magnetic blade 2.

In the magnetic toner used in the present invention, in order to reduce the magnetic strength of the magnetic toner without reducing the amount of magnetic substance in the magnetic toner, the magnetic field 1 having a weaker magnetic strength than usual is used.
It contains a magnetic material having a magnetization intensity in KOe of 10 to 40 emu / g. Examples of the magnetic substance contained in the toner include metal oxides containing elements such as iron, cobalt, nickel, copper, magnesium, manganese, aluminum and silicon. The magnetic substance used in the examples of the magnetic toner of the present invention is spinel-type iron oxide obtained by the synthesis method as shown below.

(Synthesis Example) As a reactor, a bubble oxidation type reaction tower having an internal capacity of 180 liters was used. Industrial iron sulfate is dissolved in water to prepare 40 liters of a solution having a ferrous iron concentration of 134 g / liter. Separately, 40 liters of a solution having a caustic soda concentration of 182 g / liter was prepared, and the above iron sulfate solution was added thereto with stirring to neutralize the solution so that the residual caustic soda became 5 g / liter. To this was added 50 liters of an industrial zinc hydroxide solution having a pH of 11.3 and a zinc concentration of 40 g / liter to prepare a reaction solution having a ferrous iron concentration of 40 g / liter. While maintaining the temperature of the reaction solution at 80 ° C., the oxidizing air was supplied at 10 liter / min. Was blown in at a ratio of, and an oxidation reaction was carried out. The reaction was completed in about 7 hours. Next, this slurry was washed and dried to obtain spinel type iron oxide. The obtained magnetic material has a horizontal ferret diameter of 0.25 μm, BET of 8.8 m ² / g, and magnetization intensity of 3
1.5 emu / g, coercive force 170 Oe, remanent magnetization 5.7
It was emu / g.

The magnetic toner was prepared as follows. Styrene-acrylic copolymer 54.9% by weight Negative charge control agent 0.5% by weight Magnetic substance (magnetic substance obtained in the above synthesis example) 44.4% by weight Release agent 0.2% by weight powder After mixing, the mixture was heat-kneaded with a two-roll mill set at 140 ° C. for about 30 minutes, cooled, and then coarsely pulverized and finely pulverized (jet mill). Further, fine powder and coarse powder were cut by an elbow jet classifier to obtain a toner composition. The particle size of the obtained toner was 8.5 μm in weight average diameter and the coefficient of change was 30%. 0.6% by weight of negatively chargeable colloidal silica was externally added to this to obtain a developer.

The applicant of the present invention conducted the following studies on the chargeability of toner. That is, as shown in FIG. 25, a magnetic blade 2 facing in the vicinity of the magnetic pole position of the permanent magnet 1b contained in the developing sleeve 1a, and a wire mesh member 4 made of stainless steel in the vicinity thereof are arranged. And The toner of the present invention was put in this and the chargeability was examined. As a result, in the developing device as shown in FIG. 25, the chargeability of the toner of the present invention was good.

This is a toner container 9 filled with toner.
In the vicinity of the inner magnetic blade 2, the toner in the packed state passes through the mesh member 4 and passes through the magnetic blade 2.
Therefore, it is considered that since the mesh is used to loosen the agglomeration of the toner, the contact with the mesh increases the amount of charged toner, so that good charging can be obtained. As a result, with the above configuration, when the magnetization intensity of the magnetic toner is within the above range, the image reproducibility can be improved without causing fog in the background portion. The magnetic material used in the present invention is not limited to this example, and the strength of the magnetization in the magnetic field of 1 KOe is 10-4.
0 emu / g, horizontal ferret diameter of 0.05 μm to 0.
Any magnetic substance having a thickness of 5 μm may be used. One example is Example 2
Shown in.

Embodiment 2 The present invention is not limited to the configuration of Embodiment 1 described above. A magnetic substance was produced in the same manner as in the synthesis example of Example 1 to obtain spinel iron oxide. The obtained magnetic material had a horizontal ferret diameter of 0.20 μm and BET9. m ² / g, strength of magnetization 37.
8 emu / g, coercive force 78 Oe, remanent magnetization 6.4 emu
/ G. A toner was produced using this magnetic material. The prescription is as follows. Styrene-acrylic copolymer 49.7% by weight Negative charge control agent 0.5% by weight Magnetic material (magnetic material) 49.6% by weight Release agent 0.2% by weight Obtained toner has a weight average particle diameter 6.1 μm, change coefficient 34
%Met. 0.9% by weight of negatively chargeable silica was added to this to obtain a developer. When this toner was used and placed in the developing unit of Example 1, the chargeability of the toner was stabilized. As a result, it has become possible to improve the image reproducibility.

Embodiment 3 The present invention is not limited to the construction of the above embodiment, and the grid member 4 disposed near the toner layer regulating member 2 and the mesh member of Embodiment 1 are coated with acrylic resin. With the configuration used as described above, particularly in the negatively chargeable magnetic toner of Example 1, when the magnetization intensity of the magnetic toner was within the above range, the chargeability of the magnetic toner could be further stabilized. As a result, it has become possible to improve the image reproducibility. Further, in the case of a positively chargeable toner, good results were obtained by using a structure in which a lattice-like member having positive chargeability, for example, a coating of a fluororesin is used.

Embodiment 4 The present invention is not limited to the constitution of the above-mentioned embodiment, and a grid member arranged near the magnetic blade 2 for regulating the developer amount on the developer carrying member 1 is shown in FIG. As shown in FIG. 26A, the magnetic blade 2 is provided in two steps in the vicinity thereof, and FIG.
As shown in FIG. 3, a stainless mesh member 5 and a stainless mesh member closer to the magnetic blade 2 are arranged, and the length of one side of the opening of the mesh member 5 is 100 μm.
m, and the length of one side of the opening of the mesh member 5 is smaller than the length of one side of the opening of the mesh member 5 50
μm. As a result, in all the magnetic one-component toners of Example 1, when the strength of magnetization of the magnetic toner is within the above range, the chargeability of the magnetic toner can be further stabilized, resulting in image reproducibility. Can be further improved.

Fifth Embodiment The present invention is not limited to the structure of the above-mentioned embodiment, but the grid-like members 4 and 5 arranged in the vicinity of the toner layer regulating member 2.
In the case where the mesh member 4 of Example 4 is coated with an acrylic resin and used, particularly in the negatively chargeable magnetic toner of Example 1, when the magnetization intensity of the magnetic toner is within the above range, The chargeability could be more stabilized. As a result, it has become possible to improve the image reproducibility. The arrangement of the grid-like members is not limited to all the above-mentioned embodiments, but it is preferable to appropriately select the arrangement position according to the construction of the developing device.

[0198]

【The invention's effect】

(First Invention) As described above, according to the configuration of the present invention, it is possible to reduce the magnetization intensity of the magnetic one-component toner and to stabilize the process of imparting charge to the toner. It has become possible to improve the image reproducibility in the development using the component toners.

(Second Invention) As described above, according to the constitution of the present invention, the magnetic toner is reduced in the strength of magnetization without reducing the amount of magnetic substance in the magnetic toner, and the magnetic property of the magnetic toner is reduced. It is possible to stabilize the charge application to the toner in a short time, and as a result, it is possible to improve the image reproducibility.

(Third Invention) As described above, according to the structure of the present invention, the voltage leakage of the alternating electric field between the developer carrying member and the counter electrode is prevented under high humidity, and It is possible to reduce the strength of magnetization of the magnetic toner without reducing the amount of magnetic material in the magnetic toner and stabilize the charge application to the magnetic toner, and as a result, improve the image reproducibility. I was able to do it.

(Fourth Invention) As described above, according to the constitution of the present invention, the chargeability of the toner can be stabilized, and the image reproducibility in the development of the magnetic toner is improved. Is now possible.

(Fifth Invention) As described above, according to the constitution of the present invention, the ears of the toner can be shortened and loosened, and the chargeability can be stabilized. It is now possible to improve the image reproducibility in.

(Sixth Invention) As described above, according to the constitution of the present invention, the chargeability of the toner can be stabilized, and the image reproducibility in developing the magnetic toner is improved. Is now possible.

[0204]

[Brief description of drawings]

 (First invention)

FIG. 1 is a sectional view of a developing device that is a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a developing device that is an embodiment in which a wire is used as an electrode, which is a feature of the present invention.

FIG. 3 is a cross-sectional view of a developing device according to an embodiment in which the electrodes are arranged not only on the upstream side in the rotation direction of the developer carrying member but also on the downstream side with respect to the developer regulating member.

FIG. 4 is an explanatory view of the behavior of the magnetic toner between the developer carrying member and the electrode which is a feature of the present invention.

FIG. 5 is a cross-sectional view of a developing device according to an embodiment when a non-magnetic elastic blade is used as a developer regulating member.

FIG. 6 is a cross-sectional view of a developing device according to an embodiment in which the power source applied between the developer carrier and the electrodes, which is a feature of the present invention, is different from the developing bias power source.

[0205]

[Explanation of symbols]

 1a is a developing sleeve 1b is a permanent magnet disposed in the developing sleeve 2, a developer regulating member 3, a toner conveying member 4, a developing bias power source 5, an electrode member T is toner.

(Second Invention)

FIG. 7 is a sectional view of the developing device according to the first embodiment of the present invention.

FIG. 8 is a cross-sectional view of a developing device that is an embodiment when electrodes are wires.

FIG. 9 is a cross-sectional view of a developing device according to an embodiment in which the electrodes are arranged not only on the upstream side in the rotation direction of the developer carrying member but also on the downstream side with respect to the developer regulating member.

FIG. 10 is an explanatory diagram of the behavior of the magnetic toner between the developer bearing member and the electrode, which is a feature of the present invention.

FIG. 11 is a cross-sectional view of a developing device according to an embodiment when a non-magnetic elastic blade is used as a developer regulating member.

FIG. 12 is a cross-sectional view of a developing device according to an embodiment in which the power source applied between the developer carrying member and the electrodes, which is a feature of the present invention, is different from the developing bias power source.

[0207]

[Explanation of symbols]

 1a is a developing sleeve 1b is a permanent magnet disposed in the developing sleeve 2, a developer regulating member 3, a toner conveying member 4, a developing bias power source 5, an electrode member 6, a covering member T, Toner.

(Third Invention)

FIG. 13 is a sectional view of the developing device according to the first embodiment of the present invention.

FIG. 14 is a cross-sectional view of a developing device that is an embodiment in which a wire is used as an electrode, which is a feature of the present invention.

FIG. 15 is a cross-sectional view of a developing device according to an embodiment in which the positions of electrodes are arranged not only on the upstream side in the rotation direction of the developer carrying member but also on the downstream side with respect to the developer regulating member.

FIG. 16 is an explanatory diagram of the behavior of the magnetic toner between the developer carrying member and the electrode, which is a feature of the present invention.

FIG. 17 is a cross-sectional view of the developing device according to the first embodiment when the developer regulating member is a non-magnetic elastic blade.

FIG. 18 is a cross-sectional view of a developing device according to an embodiment in which the power source applied between the developer carrying member and the electrodes, which is a feature of the present invention, is different from the developing bias power source.

[0209]

[Explanation of symbols]

 1a is a developing sleeve 1b is a permanent magnet disposed in the developing sleeve 2 is a developer regulating member 3 is a toner conveying member 4 is a developing bias power source 5 is an electrode member 6 is an insulating member T is Toner.

(Fourth Invention)

19A is a cross-sectional view of a developing device according to one embodiment of the present invention, and FIG. 19B is a stereoscopic schematic diagram for explaining the configuration of the first embodiment.

FIG. 20 is a cross-sectional view of the developing device when the vibrating member is changed into a brush shape and arranged.

FIG. 21 is an explanatory view of a cross-sectional view of a developing device in which vibration members are arranged upstream and downstream of a toner layer restriction member.

[0211]

[Explanation of symbols]

 1a is a developing sleeve 1b is a magnet disposed in the developing sleeve 2 is a magnetic blade 3a, 3b is a toner conveying member 4, a vibrating member 5, a vibration transmitter 9 is a developing container

(Fifth Invention)

FIG. 22A is a sectional view of the developing device according to the first embodiment of the present invention, and FIG. 22B is a sectional view of the developing device for explaining the operation of loosening the toner ears.

FIG. 23 is a cross-sectional view of a developing device when electrodes are arranged on the back surface of an elastic blade.

FIG. 24 is an explanatory view of a cross-sectional view of a developing device in which an electrode is arranged on the back surface in an elastic roller.

[0213]

[Explanation of symbols]

 1a is a developing sleeve 1b is a magnet disposed inside the developing sleeve 2 is an elastic blade 21 is an elastic roller 3a, 3b is a toner conveying member 4 is a power source 5 is an electrode member 9 is a developing container

(Sixth Invention)

25A is a cross-sectional view of a developing device according to an embodiment of the present invention, and FIG. 25B is a cross-sectional view of the developing device for explaining the operation of loosening toner spikes.

FIG. 26A is a cross-sectional view of the developing device when the lattice members are arranged in two stages, and FIG. 26B is a three-dimensional schematic diagram for explaining the configuration in which the lattice members are arranged in two stages. .

[0215]

[Explanation of symbols]

 1a is a developing sleeve 1b is a magnet disposed in the developing sleeve 2 is a magnetic blade 3a, 3b is a toner conveying member 4 is a lattice member 5 is a lattice member 9 is a developing container

Claims (30)

[Claims] 1. A magnetic toner containing at least a magnetic material, a developer carrying body carrying a developer containing the magnetic toner on its surface, and a regulating member for regulating application of the developer on the developer carrying body. In the developing device having a magnet inside the developer carrying member, the magnetic toner has a magnetization intensity of 10 to 40 emu / g in a magnetic field of 1 KOe (Oersted) and a horizontal ferret diameter of 0.05 to 0. A magnetic toner comprising a magnetic substance made of a metal oxide having a thickness of 5 μm, and being downstream of a developer transporting direction on the developer carrying member with respect to the developer regulating member in the developing device. A developing device, characterized in that it has means for changing the state of coupling between the magnetic toners on the developer carrying member on the side near the developer carrying member. 2. A means for changing the bonding state between magnetic toners on a developer carrying member, said means comprising at least one counter electrode for said developer carrying member, said developer regulating member. The member is arranged at a position near the developer carrying body on the downstream side of the developer carrying body in the developer carrying direction, and a power source is arranged to apply an alternating electric field between the counter electrode and the developer carrying body. Claim 1 which has the said structure.
The developing device according to 1. 3. A magnetic toner containing at least a magnetic material, a developer carrying body carrying a developer containing the magnetic toner on its surface, and a regulating member for regulating application of the developer on the developer carrying body. A developing device having a magnet inside the developer carrying member, wherein the developing device is located downstream of the developer regulating member in the developer carrying direction on the developer carrying member. It is characterized in that it has a means for changing the coupling state between the magnetic toners on the developer carrying member in the vicinity, and the magnetic toner has a magnetization intensity of 1 at a magnetic field of 1KOe.
0-40 emu / g, horizontal ferret diameter 0.05-
A magnetic toner containing a magnetic substance made of a metal oxide having a thickness of 0.5 μm. 4. The magnetic toner content of the magnetic toner is 30 to 30.
The magnetic toner according to claim 3, which is 60% by weight. 5. When the magnetic substance content in the magnetic toner is WT (wt%) and the particle size of the toner is Dt (μm), WT = − (10/3) Dt + (70 ± 15) Dt ≦ 7 The magnetic toner according to claim 3, which satisfies the following condition. 6. A magnetic toner containing at least a magnetic material, a developer carrying body carrying a developer containing the magnetic toner on its surface, and a regulating member for regulating application of the developer on the developer carrying body. In the developing device having a magnet inside the developer carrier, the magnetic toner has a magnetization intensity of 1 at a magnetic field of 1 KOe.
0-40 emu / g, horizontal ferret diameter 0.05-
A magnetic toner comprising a magnetic substance made of a metal oxide having a thickness of 0.5 μm, and in the developing device, at least one counter electrode with respect to the developer carrying member is a developer. A power source that is arranged in the vicinity of the developer carrying body on the downstream side of the developer carrying body in the developer carrying direction with respect to the regulating member and applies an alternating electric field between the counter electrode and the developer carrying body. And a surface of the counter electrode facing at least the developer carrier is formed or covered with a member having a charging polarity different from that of the magnetic toner. apparatus. 7. A magnetic toner containing at least a magnetic material, a developer carrying body carrying a developer containing the magnetic toner on its surface, and a regulating member for regulating application of the developer on the developer carrying body. A developing device having a magnet inside the developer carrying member, wherein in the developing device, at least one counter electrode is provided with respect to the developer carrying member,
A power source for applying an alternating electric field is arranged between the counter electrode and the developer carrying member on the developer carrying member on the downstream side in the developer carrying direction in the vicinity of the developer carrying member. At least the surface of the electrode facing the developer carrying member is constituted or covered with a member having a charging polarity different from the charging polarity of the magnetic toner, and the magnetic toner has a magnetic field. The magnetization intensity at 1 KOe is 10 to 40 emu / g, and the horizontal ferret diameter is 0.05.
A magnetic toner containing a magnetic substance made of a metal oxide having a particle size of 0.5 μm. 8. The content of the magnetic substance in the magnetic toner is 30 to 30.
The magnetic toner according to claim 7, which is 60% by weight. 9. When the magnetic substance content in the magnetic toner is WT (wt%) and the particle size of the toner is Dt (μm), WT = − (10/3) Dt + (70 ± 15) Dt ≦ 7 The magnetic toner according to claim 7, which satisfies the following condition. 10. The developing device according to claim 6, wherein at least a surface of the counter electrode facing the developer carrying member has an insulating property. 11. A magnetic toner containing at least a magnetic material, a developer carrying body carrying a developer containing the magnetic toner on its surface, and a regulating member for regulating application of the developer on the developer carrying body. In the developing device having a magnet inside the developer carrier, the magnetic toner has a magnetization intensity of 1 at a magnetic field of 1 KOe.
0-40 emu / g, horizontal ferret diameter 0.05-
A magnetic toner comprising a magnetic substance made of a metal oxide having a thickness of 0.5 μm, and in the developing device, at least one counter electrode with respect to the developer carrying member is a developer. A power source that is arranged in the vicinity of the developer carrying body on the downstream side of the developer carrying body in the developer carrying direction with respect to the regulating member and applies an alternating electric field between the counter electrode and the developer carrying body. A developing device, wherein at least the surface of the counter electrode facing the developer carrying member is covered with an insulating member. 12. A magnetic toner containing at least a magnetic material, a developer carrying body carrying a developer containing the magnetic toner on its surface, and a regulating member for regulating application of the developer on the developer carrying body. A developing device having a magnet inside the developer carrying member, wherein in the developing device, at least one or more counter electrodes are provided for the developer carrying member, It is arranged on the developer carrier at a position near the developer carrier on the downstream side in the developer conveying direction, and a power source for applying an alternating electric field is arranged between the counter electrode and the developer carrier, and the counter electrode. Of at least the surface of the magnetic toner facing the developer carrier is covered with an insulating member, and the magnetic toner has a magnetization intensity in a magnetic field of 1 KOe of 10 to 40 emu / g and a horizontal ferret diameter. Is 0.05
A magnetic toner containing a magnetic substance made of a metal oxide having a particle size of 0.5 μm. 13. The magnetic substance content of the magnetic toner is 30.
The magnetic toner according to claim 12, wherein the content is about 60% by weight. 14. The magnetic substance content in the magnetic toner is set to WT.
13. The magnetic toner according to claim 12, wherein WT = − (10/3) Dt + (70 ± 15) Dt ≦ 7.5 (% by weight), where Dt (μm) is the particle size of the toner. 15. A magnetic toner containing at least a magnetic material, a developer carrying body carrying a developer containing the magnetic toner on its surface, and a regulating member for regulating application of the developer on the developer carrying body. In the developing device having a magnet inside the developer carrier, the magnetic toner has a magnetization intensity of 1 at a magnetic field of 1 KOe.
0-40 emu / g, horizontal ferret diameter 0.05-
A magnetic toner comprising a magnetic substance made of a metal oxide having a thickness of 0.5 μm, and at least in the vicinity of an upstream side in the developer carrying direction on the developer carrying member with respect to the regulating member. A developing device comprising one or more vibrating members and a vibration transmitter for vibrating the vibrating members. 16. A magnetic toner containing at least a magnetic material, a developer carrying body carrying a developer containing the magnetic toner on its surface, and a regulating member for regulating application of the developer on the developer carrying body. In a developing device having a magnet inside the developer carrying member, at least one vibrating member is arranged near the upstream side in the developer carrying direction on the developer carrying member with respect to the regulating member. And a vibration transmitter for vibrating the vibrating member is provided, and the magnetic toner has a magnetization strength of 10 to 40 emu / g in a magnetic field of 1 KOe and a horizontal ferret diameter of 0.05
A magnetic toner containing a magnetic substance made of a metal oxide having a particle size of 0.5 μm. 17. The magnetic toner content of the magnetic toner is 30.
The magnetic toner according to claim 16, wherein the content is -60% by weight. 18. The magnetic substance content in the magnetic toner is set to WT.
The magnetic toner according to claim 16, wherein WT = − (10/3) Dt + (70 ± 15) Dt ≦ 7.5 (% by weight), where Dt (μm) is the particle size of the toner. 19. When a plurality of vibrating members are provided, the vibrating members are provided on the upstream side and the downstream side in the developer carrying direction on the developer carrying member with respect to the toner regulating member. The developing device according to claim 15. 20. A magnetic toner containing at least a magnetic material, a developer carrying body carrying a developer containing the magnetic toner on its surface, and a regulating member for regulating application of the developer on the developer carrying body. In the developing device having a magnet inside the developer carrier, the magnetic toner has a magnetization intensity of 1 at a magnetic field of 1 KOe.
0-40 emu / g, horizontal ferret diameter 0.05-
A magnetic toner comprising a magnetic substance made of a metal oxide having a thickness of 0.5 μm, wherein the regulation member is an elastic body regulation member, and an electrode is arranged on the back surface of the elastic body regulation member, A developing device comprising a power supply for applying an alternating electric field between the electrode and the developer carrying member. 21. A magnetic toner containing at least a magnetic material, a developer carrying body carrying on its surface a developer containing the magnetic toner, and a regulating member for regulating application of the developer on the developer carrying body. In a developing device having a magnet inside the developer carrying member, the restricting member is the elastic restricting member, an electrode is arranged on the back surface of the elastic restricting member, and the electrode and the developer carrying member are disposed. A developing device characterized in that a power source for applying an alternating electric field to the body is arranged, and the magnetic toner has a magnetization strength of 10 to 40 emu / g in a magnetic field of 1 KOe and a horizontal ferret diameter of 0.05. A magnetic toner containing a magnetic substance made of a metal oxide having a particle size of 0.5 μm. 22. The magnetic substance content of the magnetic toner is 30.
22. The magnetic toner according to claim 21, which is about 60% by weight. 23. The magnetic substance content of the magnetic toner is set to WT.
The magnetic toner according to claim 21, wherein WT = − (10/3) Dt + (70 ± 15) Dt ≦ 7.5 (wherein% by weight) and the toner particle size is Dt (μm). 24. The arrangement position of the electrode arranged on the back surface of the elastic body regulating member is arranged to the downstream side from the contact point of the elastic body regulating member and the developer carrying member. Developing device. 25. A magnetic toner containing at least a magnetic material, a developer carrying body carrying a developer containing the magnetic toner on its surface, and a regulating member for regulating application of the developer on the developer carrying body. In the developing device having a magnet inside the developer carrier, the magnetic toner has a magnetization intensity of 1 at a magnetic field of 1 KOe.
0-40 emu / g, horizontal ferret diameter 0.05-
A magnetic toner characterized by containing a magnetic substance made of a metal oxide having a thickness of 0.5 μm, and a grid in the vicinity of an upstream side in the developer carrying direction on the developer carrying member with respect to the regulating member. A developing device, wherein at least one member is provided. 26. A magnetic toner containing at least a magnetic material, a developer carrying body carrying a developer containing the magnetic toner on its surface, and a regulating member for regulating application of the developer on the developer carrying body. In a developing device having a magnet inside the developer carrying member, at least one grid-like member is provided near the regulating member on the upstream side in the developer carrying direction on the developer carrying member. The magnetic toner has a magnetization strength of 10 to 4 in a magnetic field of 1 KOe.
0 emu / g, horizontal ferret diameter 0.05-0.5μ
A magnetic toner containing a magnetic substance composed of a metal oxide of m. 27. The magnetic substance content of the magnetic toner is 30.
27. The magnetic toner according to claim 26, wherein the content is about 60% by weight. 28. The magnetic substance content of the magnetic toner is set to WT.
27. The magnetic toner according to claim 26, wherein WT = − (10/3) Dt + (70 ± 15) Dt ≦ 7.5, where (% by weight) and the particle diameter of the toner are Dt (μm). 29. When at least two grid members are arranged in the developer carrying direction on the developer carrying member, the grid members are arranged on the upstream side in the developer carrying direction. 26. The developing device according to claim 25, wherein the mesh area of the lattice of the lattice member is larger than the mesh area of the lattice of the lattice member arranged on the downstream side. 30. The developing device according to claim 25, wherein the surface of the grid-like member that can come into contact with the magnetic toner is formed of a member that exhibits a charging characteristic that is different from the charging polarity of the magnetic toner.