JPH11282201A - Magnetic toner for developing electrostatic image and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic toner for developing an electrostatic image capable of providing a high-quality image for a long period of time and smoothly supplying without deteriorating fixing performance and anti-offset performance. . SOLUTION: In a magnetic toner for developing an electrostatic image having a binder resin, wax and magnetic iron oxide, the wax is
It has a lamellar structure of 0.3 to 2.0 μm in the wax domain, and the magnetic iron oxide has Mn,
Containing 0.2 to 4.0% by weight of at least one metal element selected from the group consisting of Zn, Ni, Cu, and the like;
Further, the silicon element is contained 0.2 to 0.8 wt%, those of iron element dissolution percentage of the magnetic iron oxide up to content B _Si, 10% by weight of silicon element present up to 20 wt% _Assuming that C _Si is the content of all silicon elements present in the magnetic iron oxide, A _Si , the ratio (B _Si / A _Si ) × 100 is 45 to 85%, and (C _Si / A _Si ) X100 is 35 to 70%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic toner for developing an electrostatic image and a process cartridge used in an electrophotographic method, an electrostatic recording method, a magnetic recording method, and the like, and heat-fixes a formed visible image to a recording material. The present invention relates to a magnetic toner for developing an electrostatic charge image and a process cartridge to be used in a fixing method.

[0002]

2. Description of the Related Art Conventionally, electrophotography has been disclosed in U.S. Pat. No. 2,297,691, Japanese Patent Publication No. 42-23910.
No. (corresponding US Pat. No. 3,666,363)
As described in Japanese Patent Publication No. 43-24748 (corresponding to U.S. Pat. No. 4,071,361) and the like, many methods are known. In general, a photoconductive substance is used to form an electric latent image on a photoreceptor by various means, and then the latent image is developed with toner to form a toner image to form a visible image. According to the method, a toner image is transferred onto a transfer material such as paper, and then fixed by fixing means such as heating, pressing, and heating and pressing to obtain a copy or print.

Various developing methods for visualizing an electrostatic latent image using toner have been known. For example, U.S. Pat.
The magnetic brush method described in U.S. Pat. No. 4,063, the cascade developing method described in U.S. Pat. No. 2,618,552 and the U.S. Pat. No. 2,221,776. Many developing methods such as powder cloud method, fur brush developing method and liquid developing method are known. Among these developing methods, in particular, a magnetic brush method, a cascade method, a liquid developing method and the like using a two-component developer mainly composed of a toner and a carrier have been put to practical use. All of these developing methods are excellent methods in which good images can be obtained relatively stably, but deterioration of the carrier,
There is a problem associated with the two-component developer, that is, a change in the mixing ratio of the toner and the carrier.

In order to solve such a problem, various developing methods using a one-component developer composed of only a toner have been proposed. Among them, many are excellent in a method using a one-component developer composed of magnetic toner particles.

[0005] US Pat. No. 3,909,258 proposes a developing method for developing using an electrically conductive magnetic toner. In this method, a conductive magnetic toner is supported on a cylindrical conductive sleeve having magnetism therein, and the toner is brought into contact with an electrostatic latent image holding member having an electrostatic latent image for development. At this time, in the developing section, a conductive path is formed by the toner particles between the surface of the electrostatic latent image holding member and the surface of the sleeve, and electric charges are guided from the sleeve to the magnetic toner particles via the conductive path, thereby forming an electrostatic latent image. Due to the Coulomb force between the image area and the magnetic toner, the toner particles adhere to the image area and are developed. The developing method using the conductive magnetic toner is an excellent method that avoids the problems associated with the conventional two-component developing method.However, since the toner is conductive, the electrostatic latent image holding member having the toner image is not used. There is a problem that it is difficult to transfer electrostatically to a final supporting member such as plain paper.

As a developing method using a high-resistance magnetic toner capable of electrostatic transfer, there is a developing method utilizing dielectric polarization of toner particles. However, such a method has a problem that the developing speed is essentially low and it is difficult to obtain a sufficient density of a developed image.

Other developing methods using a high-resistance insulating magnetic toner include frictionally charging the magnetic toner particles by friction between the magnetic toner particles and friction between the magnetic toner particles and a friction member such as a sleeve to reduce the triboelectric charge. A method for developing an electrostatic latent image with a magnetic toner is known. However, these methods are problematic in that the number of times of contact between the magnetic toner particles and the friction member is small and triboelectric charging tends to be insufficient, and the charged magnetic toner particles are liable to agglomerate on the sleeve due to a strong Coulomb force between the sleeve and the sleeve. Have a point.

Japanese Patent Application Laid-Open No. 55-18656 (corresponding to US Pat. Nos. 4,395,476 and 4,473,627)
In this specification, a jumping development method that eliminates the above-mentioned problem has been proposed. This involves applying a very thin layer of magnetic toner on a sleeve, triboelectrically charging it, and then developing the magnetic toner layer on the sleeve in close proximity to the electrostatic image. This method increases the chance of contact between the sleeve and the magnetic toner by applying the magnetic toner on the sleeve very thinly, enables sufficient frictional charging of the magnetic toner, supports the magnetic toner by magnetic force, and By moving the magnet and the magnetic toner relatively, the aggregation of the magnetic toner particles is released, and an excellent image can be obtained by sufficiently rubbing the sleeve with the sleeve.

In the magnetic toner used in the above-mentioned developing method, a considerable amount of a fine powdered magnetic substance is mixed and dispersed, and a part of the magnetic substance is exposed on the surface of the toner particles. The type affects the flowability and triboelectricity of the magnetic toner. As a result, various characteristics required for the magnetic toner, such as development characteristics and durability of the magnetic toner, are affected.

More specifically, in a conventional jumping development method using a magnetic toner containing a magnetic substance, if a long-term repeated development process (for example, copying) is continued, a one-component system containing a magnetic toner is used. The fluidity of the developer is reduced, sufficient triboelectricity is not obtained, the charging tends to be non-uniform, and the fogging phenomenon easily occurs in a low-temperature and low-humidity environment, which tends to cause a problem in image quality. When the adhesiveness between the binder resin and the magnetic material constituting the magnetic toner particles is weak, the magnetic material is detached from the surface of the magnetic toner particles by the repeated development process, and adverse effects such as a decrease in the density of the toner image are caused. Tends to give.

When the dispersion of the magnetic material in the magnetic toner particles is not uniform, the magnetic toner particles containing a large amount of the magnetic material and having a small particle diameter accumulate on the sleeve, which is called image density reduction and sleeve ghost. In some cases, shading is observed.

Conventionally, magnetic iron oxides contained in magnetic toners are disclosed in JP-A-62-279352 (corresponding to US Pat. No. 4,820,603) and JP-A-62-227.
No. 8131 (corresponding US Pat. No. 4,975,214) proposes a magnetic toner containing magnetic iron oxide particles containing a silicon element.

[0013] In such magnetic iron oxide particles, silicon element is positively present inside the magnetic iron oxide particles. However, in the magnetic toner containing the magnetic iron oxide particles, the fluidity of the magnetic toner is further reduced. It has points to be improved.

Japanese Patent Publication No. 3-9045 (corresponding to European Patent Application Publication No. EP-A187434) proposes to control the shape of magnetic iron oxide particles to be spherical by adding a silicate. Since the magnetic iron oxide particles obtained by this method use silicate to control the particle size, a large amount of silicon element is distributed inside the magnetic iron oxide particles, and the presence of silicon element on the surface of the magnetic iron oxide particles Since the amount is small, the fluidity of the magnetic toner tends to be insufficiently improved.

Japanese Patent Application Laid-Open No. 61-34070 proposes a method for producing ferric oxide by adding a hydroxosilicate solution during the oxidation reaction to ferric oxide. The triiron tetroxide particles obtained by this method have Si
Although the element is present, the Si element exists in a layer near the surface of the triiron tetroxide particles, and has a problem that the surface is weak against mechanical shock such as friction.

Japanese Patent Application Laid-Open No. 5-72801 (corresponding to European Patent Application Publication No. EP-A5333069) discloses that a magnetic iron oxide particle contains 0.4 to 4% by weight of a silicon element and that the magnetic iron oxide particles have In addition, a magnetic toner containing magnetic iron oxide particles in which 44 to 84% of the total silicon element content is present has been proposed.

However, in the magnetic toner containing the magnetic iron oxide particles, although the fluidity of the toner and the adhesion between the binder resin and the magnetic iron oxide particles are improved, the magnetic toner described in the production examples is used. In the iron oxide particles, a large amount of silicic acid component is present on the outermost surface, a pore structure is formed on the surface of the magnetic iron oxide particles, the BET specific surface area of the magnetic iron oxide particles tends to be high, After being left in a high-humidity environment for a long period of time, the magnetic toner having a tendency to have reduced triboelectric charging characteristics.

Japanese Patent Application Laid-Open No. 4-362954 (corresponding to European Patent Application Publication No. EP-A468525) discloses magnetic iron oxide particles containing both a silicon element and an aluminum element. It is rare.

Japanese Patent Application Laid-Open No. Hei 5-213620 discloses magnetic iron oxide particles containing a silicon component and having a silicon component exposed on the surface. However, as described above, further improvement in environmental characteristics is desired. It is rare.

JP-A-7-239571 describes that a magnetic iron oxide particle contains a silicon component and further adjusts the Fe / Si ratio on the outermost surface. This improves the triboelectric charging property in a high-humidity environment.However, the magnetic iron oxide particles described in the production examples tend to have a high bulk density, and even when converted to toner, they are more likely to be used in a developing device. It becomes easier to tighten. These toners are pressed by the toner's own weight and the agitating device, so that the toner tends to be packed in the developing device, thereby causing a shortage of toner supply to the sleeve and causing a fading phenomenon in which an image is stripped. Easier to do.

JP-A-9-59024 and 9-59
No. 025 discloses that Si is converted to 1.7 to 4.
Containing 5 atomic% of silicon, and as a metal element other than iron, M
It describes a magnetite particle containing 0 to 10 atomic% with respect to Fe of one or more metal elements selected from n, Zn, Ni, Cu, Al, and Ti. As a result, the magnetic properties are improved, and the chargeability can be improved. However, merely adding the above metal has not sufficiently improved the flowability of the toner, and has a point to be further improved. I have.

In recent years, devices using electrophotography have begun to be used in computer output printers, facsimile machines, etc. in addition to conventional copiers. For example, as for printer devices, LBP printers or LED printers have become mainstream in the market these days, and the direction of technology is as follows.
Conventionally, 240, 300 dpi was replaced with 400, 60
0, 800, and even higher resolutions of 1200, 2400 dpi. Accordingly, higher definition has been required for the developing system. As computers become more sophisticated, the output images are required to have higher definition and higher image quality.Moreover, with the spread of personal computers, maintenance can be performed more easily, and at the same time, higher As the reliability has been strictly pursued, the performance required of the printer has become higher, and if the performance of the toner cannot be improved, a better machine cannot be realized. For example, the most important performance required of toner in digital printers and copying of high-resolution images is fixing performance. Various methods and devices have been developed for the fixing step, but the most common method at present is a pressure heating method using a heat roller. The pressure heating method using a heating roller performs fixing by allowing the toner image surface of a sheet to be fixed to pass through the surface of a heat roller having a surface formed of a material having a releasable property with respect to the toner while contacting the surface under pressure. It is. In this method, since the surface of the heat roller and the toner image of the sheet to be fixed come into contact with each other under pressure, the heat efficiency at the time of fusing the toner image onto the sheet to be fixed is extremely good, and the fixing can be performed quickly. And is very effective in high speed electrophotographic copiers.

Conventionally, for the purpose of preventing the toner from adhering to the surface of the fixing roller, for example, the roller surface is formed of a material having excellent releasability to the toner, such as silicone rubber or a fluorine-based resin. In order to prevent the roller surface from being fatigued, the roller surface is coated with a thin film of a liquid having good releasability such as silicone oil. However, this method is extremely effective in preventing toner offset, but has a problem that a fixing device is complicated because an apparatus is required to supply the liquid for preventing offset.

Therefore, a release agent such as low molecular weight polyethylene or low molecular weight polypropylene is added to the toner in view of supplying the anti-offset liquid during heating from the toner instead of using a silicone oil supply device. A method has been proposed. If a large amount of such an additive is added in order to obtain a sufficient effect, filming on a photoreceptor or contamination of the surface of a toner carrier such as a carrier or a sleeve will cause deterioration of an image and pose a practical problem. Therefore, a small amount of release agent is added to the toner to such an extent that the image is not deteriorated, and a small amount of release oil is supplied or the offset toner is cleaned by a roll-up type device using a member such as a web. It has been used together.

However, in view of recent demands for miniaturization, weight reduction, and high reliability, it is preferable to remove even these auxiliary devices.

It is known that a wax is contained in a toner as a release agent. For example, JP-A-52-330
No. 4, JP-A-52-3305, JP-A-57-3305.
A technique such as 52574 is disclosed.

These waxes are used to improve the offset resistance of the toner at low and high temperatures. However, while these properties are improved, blocking resistance is deteriorated and developability is deteriorated.

Further, as a toner containing two or more types of wax in order to exhibit the effect of adding wax from a low temperature range to a high temperature range, for example, Japanese Patent Publication No.
JP 3305, JP-A-58-215659, JP-A-62-100775, JP-A-4-12467
6, JP-A-4-299357, JP-A-4-299357
Techniques such as Japanese Patent No. 329553 and Japanese Patent Application Laid-Open No. 5-197192 are disclosed.

However, none of these toners satisfies all of the performances, causing some problems. For example, high-temperature offset resistance and developability are excellent, but low-temperature fixability is just one step away, or low-temperature offset resistance and low-temperature fixability are excellent, but blocking resistance is slightly inferior and developability decreases. Or the offset resistance at low and high temperatures is not compatible, or the toner coating is uneven due to the free wax component, causing blotches, causing image defects and fogging on the image. Was happening.

The waxes contained in these toners simply contained a wax component in a wide or skewed temperature range with respect to an endothermic peak at the time of temperature rise of a DSC curve measured by a differential scanning calorimeter. Many of the components were insufficient to satisfy the above-mentioned performance, or deteriorated or had little effect.

Further, JP-A-8-278657, JP-A-8-334919, and JP-A-8-334920.
In order to obtain a toner having excellent low-temperature fixability and anti-offset properties, Japanese Patent Application Laid-Open Publication No. H11-216, and the like propose that the toner contains two types of wax components. Also, Japanese Patent Application Laid-Open No. 7-281
No. 478 discloses a polypropylene-based resin for lowering the minimum fixing temperature and increasing the hot offset temperature.
It has been proposed to use an acid-modified polyethylene resin as a release agent for toner.

However, in the toner using these release agents, although the range of the low-temperature fixing property and the high-temperature offset resistance is expanded, the deterioration of the toner due to the high durability occurs, and the toner is used for a long time. It is completely insufficient for stable use, and further improvement of the toner has been desired.

The demand for maintainability and miniaturization of printers, facsimile machines and the like has been increasing due to the spread of personal computers. A method using a process cartridge in which an apparatus, a latent image holding member (photosensitive drum) for holding an electrostatic image, a cleaner, a charging member, and the like are integrated has become mainstream.

In recent years, further miniaturization of the image forming apparatus main body has been demanded, and accordingly, the process cartridge and the developing device have also been required to be miniaturized, and the toner accommodating portion which is a part of the developing device has an irregular shape. I need to.

The conventional toner storage section is provided with a rotatable toner stirring member for stirring and supplying the toner therein. For this reason, the shape of the toner storage portion is limited to a substantially cylindrical shape, and the design freedom such as a flat shape or a square shape is limited.

[0036]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic toner for developing an electrostatic charge image and a process cartridge which solve the above-mentioned problems.

That is, an object of the present invention is to provide a high-quality image in any environment for a long period of time without impairing the fixing performance and the anti-offset performance.
An object of the present invention is to provide a magnetic toner for developing an electrostatic image and a process cartridge that can smoothly supply toner even when the toner storage section has an irregular shape.

[0038]

According to the present invention, there is provided a magnetic toner for developing electrostatic images having toner particles containing at least a binder resin, wax and magnetic iron oxide, wherein the wax is contained in the toner by a transmission electron microscope. Has a lamellar structure of 0.3 to 2.0 μm in the wax domain observed by the magnetic iron oxide, based on the iron element,
Mn, Zn, Ni, Cu, Co, Cr, Cd, Al, S
a magnetic element containing 0.2 to 4.0% by weight of at least one metal element selected from the group consisting of n and Mg, and 0.2 to 0.8% by weight of a silicon element; Iron oxide has an iron element dissolution rate of 20% by weight of the magnetic iron oxide.
The ratio of the content of silicon element B _Si present up to and the content of all silicon elements A _Si present in the magnetic iron oxide (B _Si /
A _Si) is × 100 is 45 to 85%, and the ratio between the content C _Si and the content A _Si of the silicon element iron element dissolution ratio of the magnetic iron oxide is present in up to 10 wt% (C _Si / A _Si )
× 100 is 35 to 70%, and relates to a magnetic toner for developing electrostatic images.

Further, according to the present invention, there is provided a process cartridge detachably mounted to an image forming apparatus main body, the process cartridge comprising: a latent image holding member for holding an electrostatic image; A charging member for charging the latent image holding member by applying a voltage from outside; and a toner for forming a toner image by developing an electrostatic charge image held on the latent image holding member. The developing device has a toner storage unit for storing the toner, and a reciprocally movable stirring unit for stirring and supplying the toner stored in the toner storage unit. Means, wherein the toner is a magnetic toner for developing an electrostatic charge image having the above-described structure.

[0040]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, by imparting the following features to a toner, appropriate flow performance can be maintained even under high temperature and high humidity, and a wide range of fixing and offset resistance can be secured. Thus, even with a high degree of durability, a remarkable improvement effect of being able to stably provide a high-quality image for a long period of time was obtained.

That is, since the wax has a lamellar structure of a certain size, the wax domain phase can have both high rigidity and high impact properties.
Even after a high degree of durability, it is possible to obtain a desirable high-quality image for a long period of time without causing deterioration of the toner. In addition, because of its high elasticity, the anti-offset performance at high temperatures can be improved. In addition, since the dispersed phase has a specific size, it is possible to favorably plasticize the resin binder, and it is also possible to have good fixing properties.

The “lamella structure” is a layered structure formed by crystallization of a crystalline polymer by folding of molecular chains, and is a higher-order structure of an energy stable crystal structure.

A feature of the present invention is that the wax has a lamellar structure having a layer thickness of 0.3 to 2.0 μm in a dispersed phase observed in a toner by a transmission electron microscope, This specific example is shown in FIG.

That is, the wax is distributed in the toner with a certain degree of dispersed particle size, and the crystal structure of the wax observed in the wax phase forms a layered structure (lamella structure) having several layers. Is observed.

The observation of the dispersed phase of the wax in the toner is performed by observing the cross section of the toner with a transmission electron microscope (TEM).

The specific method will be described below.

That is, after sufficiently dispersing the toner particles in a cold-setting epoxy resin, the resulting cured product is cured in an atmosphere at a temperature of 40 ° C. for 2 days.
If necessary, osmium tetroxide is used in combination, and then dyed. Then, a flaky sample is cut out using a microtome equipped with diamond teeth, and the state of the toner particle cross-sectional layer is measured using a transmission electron microscope (TEM).

In the present invention, the cross section layer of the toner particles dyed as described above is observed with a transmission electron microscope enlarged photograph (magnification: 200,000), and 50 wax domains are sampled. The lamella structure can be confirmed at 60% by number or more (preferably at least 80% by number), and the thickness of the maximum layer thickness portion of the lamella structure is measured for all the confirmed lamella structures. The average value of the thickness of the layer thickness portion is defined as the layer thickness of the lamella structure.

If no lamella structure can be confirmed in more than 60% by number of the sampled wax domains, it is assumed that no lamella structure is formed in the wax domain of the toner particle cross-sectional layer. It is excluded from the present invention.

In the present invention, the wax is characterized in that a lamellar structure having a layer thickness of 0.3 to 2.0 μm is formed in the wax domain in the toner particles. 0.3
If it is less than μm, the effects of the lamellar structure, that is, high rigidity, high impact resistance, and high elasticity are lost, and the performance of the toner is not exhibited. On the other hand, if it exceeds 2.0 μm, the dispersed particle diameter of the wax becomes too large, causing problems in charging performance such as charge-up. Further, it may cause adverse effects such as wax filming.

In the present invention, observation was performed using the following apparatus and method.

Transmission electron microscope (TEM): Model H-7100FA manufactured by Hitachi, Ltd. Conditions: Acceleration voltage: 100 kV Sample preparation: Ruthenium tetroxide stained ultrathin section method

Further, in the present invention, the magnetic iron oxide used in the magnetic toner is obtained by replacing silicon element with iron element.
0.2 to 0.8% by weight, and as metal elements other than iron, Mn, Zn, Ni, Cu, Co, Cr, C
d, containing at least one metal element (other metal element) selected from the group consisting of Al, Sn and Mg in an amount of 0.2 to 4.0% by weight based on the iron element. One.

By using these other metal elements together with the silicon element in the magnetic iron oxide, the precipitation of the silicon compound in the vicinity of the surface of the magnetic iron oxide is suppressed to a certain extent, and this is supplemented with the other metal to form the magnetic iron oxide. Can be suppressed without impairing the fluidity improving effect.

In the present invention, the magnetic iron oxide contains 0.2 to 0.8% by weight, preferably 0.3 to 0.7% by weight, of silicon element based on iron element.

When the content of the silicon element is less than 0.2% by weight, the effect of improving the magnetic toner, particularly the improvement of the fluidity of the magnetic toner, is weak. If the content of the silicon element is more than 0.8% by weight, the charging characteristics are degraded in environmental characteristics, especially in long-term storage and long-term durability in a high-humidity environment. The dispersibility of the magnetic iron oxide in the binder resin also decreases.

When the content of the other metal element is less than 0.2% by weight, the effect of improving the fluidity of the toner is small. When the content of the other kind of metal element is more than 4.0% by weight, the magnetic iron oxide particles are likely to adversely affect the charging characteristics of the magnetic toner.

In the present invention, the content A _Si of the total silicon element present in the magnetic iron oxide and the content B of the silicon element present when the iron element dissolution rate of the magnetic iron oxide is up to 20% by weight.
The ratio of the _{Si (B Si / A Si)} × 100 is 45 to 85%, preferably 50 to 80%, the iron element dissolution ratio is 10%
The ratio (C _Si / A _Si ) × 100 of the silicon element content C _Si existing up to the total silicon element content A _Si is preferably 35 to 70%, preferably 40 to 65%.

When (B _Si / A _Si ) × 100 is smaller than 45%, or when (C _Si / A _Si ) × 100 is smaller than 35%, a large amount of silicon exists inside the magnetic material, In addition to the fact that the iron oxide production process is likely to deteriorate, magnetic iron oxide may be unstable in magnetic properties. (B _Si / A _Si )
If × 100 is greater than 85%, or (C _Si /
If (A _Si ) × 100 is greater than 70%, a large amount of silicon element is present in the surface layer of the magnetic iron oxide, making it brittle against mechanical impact, and harmful effects are likely to occur when used in a magnetic toner.

In the present invention, Mn, Zn, Ni, and C are present when the iron dissolution rate of the magnetic iron oxide is up to 20% by weight.
content of one or more metal elements selected from the group consisting of u, Co, Cr, Cd, Al, Sn and Mg
_Metal and the ratio of the content A _Metal of the metal group element present in the magnetic iron oxide _{(B Metal / A Metal) ×} 100
Is preferably 40 to 100%. (B _Metal / A
_{If (Metal} ) × 100 is less than 40%, other metals are unlikely to act effectively in the vicinity of the surface, easily deteriorate in the manufacturing process, and may become magnetic iron oxide having unstable magnetic properties.

In the present invention, when the magnetic iron oxide contains Mn element as another metal element, the M
The content of the n element is preferably 0.1 to 0 based on the iron element.
7 to 2.0% by weight, more preferably 0.8 to 1.8%
% By weight.

When the content of the Mn element is less than 0.7% by weight, the effect of improving the magnetic toner, particularly the improvement of the fluidity of the magnetic toner, is weak. When the content of the Mn element is more than 2.0% by weight, the charging characteristics may be degraded in environmental characteristics, particularly in long-term storage and long-term durability in a high-humidity environment. The dispersibility of the magnetic iron oxide in the binder resin of the toner tends to decrease.

In the present invention, the content A _Mn of the total Mn element present in the magnetic iron oxide and the content B _Mn of the Mn element present when the iron element dissolution rate of the magnetic iron oxide is up to 20% by weight. The ratio B _Mn / A _Mn × 100 is preferably 50 to 90%,
More preferably, it is 60 to 85%. B _Mn
When / A _Mn × 100 is smaller than 50% and a large amount of Mn element is present inside the magnetic material, the manufacturing process is likely to be deteriorated, and the magnetic properties may be unstable, resulting in magnetic iron oxide. . If B _Mn / A _Mn × 100 exceeds 90%, a large amount of Mn element is present in the surface layer of the magnetic iron oxide, making it brittle against mechanical impact and easily adversely affecting the charging characteristics.

In the present invention, when the magnetic iron oxide contains a Zn element as another metal element, the content of the Zn element in the magnetic iron oxide is preferably 0.2 to 0 based on the iron element. It is preferably 0.8% by weight, more preferably 0.3 to 0.7% by weight.

When the content of the Zn element is less than 0.2% by weight, the effect of improving the fluidity of the magnetic toner is weak. Z
When the content of the n element is more than 0.8% by weight, the charging characteristics may deteriorate in the environmental characteristics and long-term durability, and further, the durability of the toner and the magnetic iron oxide in the toner binder resin may be reduced. Tends to decrease in dispersibility.

In the present invention, the content A _Zn of the total Zn element present in the magnetic iron oxide and the content B _Zn of the Zn element present when the dissolution rate of the iron element of the magnetic iron oxide is up to 20% by weight. The ratio B _Zn / A _Zn × 100 is preferably 50 to 90.
%, More preferably 55 to 90%.
When _BZn / _AZn x 100 is smaller than 50% and Zn element is present in a large amount in the magnetic material, the manufacturing process is easily deteriorated, and magnetic iron oxide having unstable magnetic properties is also used. May be. When _BZn / _AZn * 100 exceeds 90%, a large amount of Zn element is present in the surface layer of the magnetic iron oxide, making it brittle against mechanical shock. When used in a magnetic toner, adverse effects are likely to occur. .

In the present invention, when the magnetic iron oxide contains a Cu element as another metal element, the content of the Cu element in the magnetic iron oxide is preferably 0.01 to 0 based on the iron element. The content is preferably 0.8% by weight, more preferably 0.05 to 0.7% by weight.

When the content of the Cu element is less than 0.01% by weight, the effect of improving the magnetic toner, particularly the improvement of the fluidity of the magnetic toner, is weak. When the content of the Cu element is more than 0.8% by weight, the charging characteristics may be deteriorated in environmental characteristics, particularly in long-term storage and long-term durability under high humidity. Dispersibility of the magnetic iron oxide in the binder resin tends to decrease.

In the present invention, the content A _Cu of the total Cu element present in the magnetic iron oxide and the content B _Cu of the Cu element present when the iron element dissolution rate of the magnetic iron oxide is up to 10% by weight are obtained. The ratio B _Cu / A _Cu × 100 is preferably 70-100
%, More preferably 80 to 100%.

B _Cu / A _Cu × 100 is smaller than 70%,
When a large amount of Cu element is present inside the magnetic body, the manufacturing process is liable to be deteriorated, and magnetic iron oxide may be unstable in magnetic properties.

In the present invention, when the magnetic iron oxide contains a Ni element as another metal element, the content of the Ni element in the magnetic iron oxide is preferably 0.1 to 0 based on the iron element. It is preferably 0.6% by weight, more preferably 0.2 to 0.6% by weight.

When the content of the Ni element is less than 0.1% by weight, the effect of improving the magnetic toner, particularly the improvement of the fluidity of the magnetic toner, is weak. When the content of the Ni element is more than 0.6% by weight, the charging characteristics may be degraded in environmental characteristics, particularly in long-term storage and long-term durability in a high-humidity environment. The dispersibility of the magnetic iron oxide in the binder resin of the toner also deteriorates.

In the present invention, the ratio of the total Ni element content A _Ni present in the magnetic iron oxide to the Ni element content B _Ni present when the iron element dissolution rate of the magnetic iron oxide is up to 20%. B _Ni / A _Ni × 100 is preferably 40 to 100%,
More preferably, it is 50 to 100%.

B _Ni / A _Ni × 100 is smaller than 40%,
When a large amount of Ni element is present inside the magnetic material, the manufacturing process is liable to be deteriorated, and magnetic iron oxide may be unstable in magnetic properties.

In the present invention, the magnetic iron oxide has a sphericity of preferably from 0.8 to 1 based on a measuring method described later.
It is preferably 0, more preferably 0.82 to 1.0. When the sphericity is smaller than 0.8, the magnetic iron oxide particles come into surface-to-surface contact, and in the case of small magnetic iron oxide particles having a particle size of about 0.1 to 1.0 μm, a mechanical shear force is applied. However, the particles cannot be easily separated from each other, so that the magnetic iron oxide may not be sufficiently dispersed in the magnetic toner.

Next, the structure and production method of the magnetic iron oxide used in the present invention will be described.

The silicon element and other metal elements in the magnetic iron oxide used in the present invention are basically present both inside and on the surface of the magnetic iron oxide.

The distribution of internal metal elements of the magnetic iron oxide shown in the examples of the present invention was examined by an acid dissolution method. As a result, silicon and other metal elements were present from the center of the magnetic iron oxide, and were directed toward the surface. It was found that the content increased in a gradient manner.

The magnetic iron oxide having a silicon element according to the present invention is produced, for example, by the following method.

Predetermined amounts of Mn, Zn, N
After adding at least one metal salt and silicate selected from i, Cu, Co, Cr, Cd, Al, Sn and Mg, an alkali such as sodium hydroxide equivalent to or more than equivalent to the iron component is added. In addition, an aqueous solution containing ferrous hydroxide is prepared. Air is blown in while maintaining the pH of the prepared aqueous solution at pH 7 or more (preferably pH 8 to 10), and while the aqueous solution is heated to 70 ° C. or more, the oxidation reaction of ferrous hydroxide is carried out. First, a seed crystal is produced.

Next, an aqueous solution containing about 1 equivalent of ferrous sulfate based on the amount of the alkali previously added is added to the slurry-like liquid containing the seed crystals. The reaction of ferrous hydroxide is promoted while blowing air while maintaining the pH of the solution at 6 to 10, and magnetic iron oxide particles are grown with the seed crystal as a core. The pH of the solution shifts to the acidic side as the oxidation reaction proceeds, but it is preferable that the pH of the solution is not less than 6. It is preferable that the pH of the solution is adjusted at the end of the oxidation reaction so that a predetermined amount of another metal compound is unevenly distributed on the surface layer and the surface of the magnetic iron oxide particles.

Examples of the silicate used for the addition include sodium silicate and potassium silicate. As metal salts other than iron used for the addition, sulfates, nitrates and chlorides can be used.

As the ferrous salt, generally, iron sulfate produced as a by-product in the production of titanium sulfate, iron sulfate produced as a by-product of cleaning the surface of a steel sheet, and iron chloride can be used. .

The method of producing magnetic iron oxide by the aqueous solution method generally uses an iron concentration of 0.5 to 2 mol / liter based on the prevention of an increase in viscosity during the reaction and the solubility of iron sulfate. Generally, the lower the concentration of iron sulfate, the smaller the particle size of the product tends to be. At the time of the reaction, the larger the amount of air and the lower the reaction temperature, the more easily the particles are atomized.

According to the above-mentioned production method, when observed by transmission electron microscopy, magnetic iron oxide particles containing a silicate element and another kind of metal element were formed into spherical particles mainly formed on a curved surface having no plate-like surface. It is preferable to produce a magnetic iron oxide containing almost no octahedral particles, and to use the magnetic iron oxide in the toner.

In the present invention, the magnetic iron oxide particles preferably have a bulk density of 0.4 to 0.8 g / m ³ , more preferably 0.5 to 0.7 g / m ³ , based on a measuring method described later.
It is preferable that m ³ be satisfied. When the bulk density is less than 0.4 g / m ³ , it adversely affects the physical miscibility of the toner with other constituent materials during the production of the toner,
The dispersibility of the magnetic iron oxide in the toner tends to deteriorate.
Further, when the bulk density exceeds 0.8 g / m ³ , when the magnetic toner is used, it tends to be easily tightened in the developing device,
Fading may occur.

In the present invention, the magnetic iron oxide has a number average particle size of 0.05 to 1.
The thickness is preferably from 00 μm, more preferably from 0.10 to 0.40 μm, in view of the dispersibility of the magnetic toner in the binder resin and the uniformity of charging. When the number average particle diameter of the magnetic iron oxide is larger than 1.00 μm, the number of the magnetic iron oxide particles contained in the toner is reduced, so that the dispersion of the magnetic iron oxide in the binder resin is biased. And the uniformity of charging is impaired. Number average particle size of magnetic iron oxide is 0.05μm
If the diameter is smaller than the above range, the adhesive force between the magnetic iron oxide particles increases, and the dispersibility in the binder resin deteriorates.

The method for measuring various physical property data of the magnetic iron oxide in the present invention will be described below in detail.

(1) Amount of Metal Element In the present invention, the content of the metal element other than iron in the magnetic iron oxide (based on the iron element), the dissolution rate of the iron element, and the metal other than iron relative to the dissolution rate of the iron element The content of the element can be determined by the following method. For example, 5
Put about 3 liters of deionized water in a liter beaker and heat in a water bath to 45-50 ° C. About 25 g of magnetic iron oxide slurried with about 400 ml of deionized water is added to the 5 liter beaker with the deionized water while washing with about 300 ml of deionized water.

Next, while maintaining the temperature at about 50 ° C. and the stirring speed at about 200 rpm, a special grade hydrochloric acid or a mixed acid of hydrochloric acid and hydrofluoric acid is added to start dissolution. At this time, the hydrochloric acid aqueous solution is about 3N. Approximately 20m several times from the start of dissolution until it is completely dissolved and transparent
Sample 1 and filter through a 0.1 μm membrane filter to collect the filtrate. Filter the filtrate to plasma emission spectroscopy (IC
By P), the iron element and the metal element other than the iron element are quantified.

The iron element dissolution rate for each sample is calculated by the following equation.

[0092]

(Equation 1) The content of metal elements other than iron element for each sample is calculated by the following equation.

[0093]

(Equation 2) The total content A of the metal elements other than the iron element in the magnetic iron oxide corresponds to the concentration of the metal element per unit weight (mg / liter) of the magnetic iron oxide after being completely dissolved.

The contents B and C of the metal elements other than the iron element of the magnetic iron oxide are determined when the dissolution rate of the magnetic iron oxide is 20% or 10%.
% Corresponds to the concentration (mg / liter) of metal elements other than iron element per unit weight of the magnetic iron oxide to be detected.

(2) Bulk Density of Magnetic Iron Oxide The bulk density of the magnetic iron oxide particles in the present invention is determined according to JIS-K
It measured according to the pigment test method of -5101.

(3) Sphericity of Magnetic Iron Oxide The sphericity of magnetic iron oxide in the present invention is calculated as follows.

[0097]

(Equation 3) The sphericity (Ψ) is measured using an electron microscope (Hitachi, Ltd./H-700).
Using a sample of magnetic iron oxide treated on the copper mesh of the collodion film in H), an image was taken at 10,000 times at an applied voltage of 100 kV, and the printing magnification was 3 times, and the final magnification was 30000.
Double it. Thus, the shape is observed, 100 magnetic iron oxide particle specimens are randomly selected, the maximum length and the minimum length are measured, and the calculated values are averaged.

(4) Number Average Particle Size of Magnetic Iron Oxide From a transmission electron micrograph (magnification: 30,000 times), 100 particles were randomly selected from the photograph, and the particle diameter was measured. The particle size was used.

The wax used in the magnetic toner for developing an electrostatic image of the present invention preferably has an acid value of 1 to 15 mgKOH / g.

By having a constant acid value, it was possible to control the dispersibility in the resin component, and at the same time, it was possible to control the higher order structure of the wax phase.

If the acid value is less than 1 mgKOH / g, the effect of the acid cannot be sufficiently exerted. In addition, the acid value is 15 mg KO
If it exceeds H / g, it is liable to be affected by environmental humidity, and it is difficult to obtain stable charging performance, which is not preferable.

The endothermic peak derived from the melting point of the wax measured by DSC is preferably in the range of 110 to 150 ° C. from the viewpoint of low-temperature fixing.

If the temperature is lower than 110 ° C., the storage stability may be impaired and the offset resistance may be deteriorated, which is not preferable. If the temperature exceeds 150 ° C., the fixing performance may be adversely affected.

In the present invention, the endothermic peak temperature derived from the melting point of the wax was measured using a differential thermal analyzer (DSC measuring device), DSC-7 (manufactured by PerkinElmer) under the following conditions.

Sample: 5 to 20 mg, preferably 10 mg Measurement method: Put the sample in an aluminum pan, and use an empty aluminum pan as a reference.

Temperature curve: Temperature rise I (20 ° C. → 180 ° C., temperature rise rate 10 ° C./min.) Temperature fall I (180 ° C. → 10 ° C., temperature fall rate 10 ° C./min.) Temperature rise II (10 ° C. → 180 ° C, heating rate 10 ° C / min.) The endothermic peak temperature measured by heating II is defined as a measured value.

Examples of the wax used in the present invention include a propylene homopolymer, an ethylene homopolymer, and a copolymer of propylene and another olefin (particularly, ethylene is preferable).

It is preferable that the wax contains an ethylene-propylene copolymer from the viewpoint of maintaining a wide range of fixing property and anti-offset property. In particular, the content of the ethylene-propylene copolymer component is preferably 3 to 20% by weight, more preferably 3 to 10% by weight.

When the content of the ethylene component is 3% by weight or more, the crystallinity of the wax is controlled, the dispersibility of the wax component in the toner is improved, and the wax acts as a plasticizer for the binder resin. This can lower the softening point of the toner. Also, if the ethylene component exceeds 20% by weight, wax tack (viscosity) appears,
Rather, the fixing characteristics may be adversely affected, and there is an undesirable combination.

[0110] End-modified polypropylene wax and acid-modified polypropylene wax may be mixed and used.

The acid monomer used for modifying the polypropylene wax most preferably contains at least one of a carboxyl group, a carboxylic anhydride group and a carboxylate group. For example, acrylic acid such as acrylic acid, methacrylic acid, α-ethylacrylic acid, crotonic acid and its α- or β-alkyl derivatives, fumaric acid, maleic acid, unsaturated dicarboxylic acids such as citraconic acid and its monoester derivatives or There is maleic anhydride or the like, and a polypropylene wax having a desired acid value is obtained by subjecting such monomers to single or mixture and modifying reaction.

The polypropylene wax is an acid monomer selected from at least one of maleic acid, maleic acid half ester, and maleic anhydride in relation to constituent monomers preferably contained in a resin polymer component described later. It is preferable that the wax is modified polypropylene wax.

Examples of the method for producing the wax used here include a method of radically polymerizing an olefin such as ethylene and propylene under high pressure, a method of polymerizing under low pressure with a Ziegler catalyst, and a high-molecular-weight polyolefin obtained by these methods. There are a method of thermally decomposing the system resin, a method of obtaining from a synthesis gas composed of carbon monoxide and hydrogen by a Fischer-Tropsch method, and any of those obtained by any of the methods can be used.

The kind of the binder resin used in the present invention includes, for example, a homopolymer of styrene such as polystyrene, poly-p-chlorostyrene and polyvinyltoluene and a substituted product thereof; styrene-p-chlorostyrene copolymer. Copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylate copolymer, styrene-methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene- Acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile- Styrene copolymers such as indene copolymers Coalescence: polyvinyl chloride, phenolic resin, natural modified phenolic resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane resin, polyamide resin, furan resin, epoxy resin, xylene Resins, polyvinyl butyral, terpene resins, cumarone indene resins, petroleum resins and the like can be used. Further, a crosslinked styrene resin is also a preferable binder resin.

Examples of comonomers for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, and the like.
Such as dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, etc. A monocarboxylic acid having a heavy bond or a substituted product thereof;
For example, a dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, dimethyl maleate, and the like; and vinyl chloride;
Vinyl esters such as vinyl acetate, vinyl benzoate and the like, for example, ethylene olefins such as ethylene, propylene, butylene and the like; vinyl ketones such as vinyl methyl ketone and vinyl hexyl ketone;
For example, vinyl monomers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether and the like; and vinyl monomers such as used alone or in combination are used. Here, as the cross-linking agent, a compound having two or more polymerizable double bonds is mainly used, for example, an aromatic divinyl compound such as divinylbenzene, divinylnaphthalene or the like; for example, ethylene glycol diacrylate, ethylene glycol Dimethacrylate, 1,3
Carboxylic acid esters having two double bonds such as butanediol dimethacrylate; divinylaniline,
Divinyl compounds such as divinyl ether, divinyl sulfide and divinyl sulfone; and compounds having three or more vinyl groups can be used alone or as a mixture.

In the present invention, the polymer component of the toner preferably does not substantially contain a component insoluble in tetrahydrofuran (THF).

The THF-insoluble content is determined by the T of the polymer component of the toner.
It indicates the weight ratio of the polymer component (substantially crosslinked polymer) insoluble in the HF solvent, and can be used as a parameter indicating the degree of crosslinking of the polymer component containing the crosslinking component. The THF-insoluble matter is defined as having a value measured as follows.

0.5 to 1.0 g of the toner sample was weighed (W ₁ g), and the sample was filtered with a cylindrical filter paper (for example, No. 86 manufactured by Toyo Roshi Kaisha, Ltd.)
R) and run through a Soxhlet extractor, where T
After extracting with 100 to 200 ml of HF for 6 hours and evaporating the soluble component extracted with the solvent, 10
After vacuum drying for several hours at 0 ° C., the amount of the THF-soluble resin component is weighed (W ₂ g). The weight of the components other than the resin components such as the magnetic substance, pigment and wax in the toner is defined as (W ₃ g).
The THF-insoluble content is obtained from the following equation.

THF insoluble matter (%) = [｛W ₁ − (W ₃ + W)
₂ ) {/ (W ₁ -W ₃ )] × 100 If the content of THF insolubles exceeds 5% by weight, the low-temperature fixability decreases.

Gel Permeation Chromatography (GPC) Measured by THF Soluble Content of Polymer Component
Has a molecular weight of at least 3 × 10 ^{3 to} 3
It has a main peak in a region of × 10 ⁴ (more preferably, 5 × 10 ³ to 2 × 10 ⁴ ) and a molecular weight of 1 × 10 ⁵ to
3 × 10 ⁶ (more preferably, 5 × 10 ⁵ to 1 × 10 ⁶ )
It is preferable to have a subpeak or a shoulder in the region.

If the main peak is less than 3 × 10 ³ , the storage stability and high-temperature offset resistance may be adversely affected, and if it exceeds 3 × 10 ⁴ , the fixability may be adversely affected. Also, 1 × 10 ^{5 to} 3 × 10 ⁶
By having a sub-peak or a shoulder in the range, while improving the anti-offset performance of the toner,
It is possible to disperse the wax used in the present invention into a higher-order structure that produces a preferable lamellar structure in order to generate an appropriate viscosity in the toner.

In the present invention, the molecular weight distribution of the polymer component is determined by GPC (gel permeation chromatography).
Is measured under the following conditions.

<Conditions for GPC Measurement of Polymer> Apparatus: GPC-150C (manufactured by Waters) Column: KF801 to 807 (manufactured by Shodex) Temperature: 40 ° C. Solvent: THF (tetrahydrofuran) Flow rate: 1.0 ml / Min. Sample: 0.1 m of a sample having a concentration of 0.05 to 0.6% by weight
l injection

The polymer component used in the present invention comprises 0.5
It preferably has an acid value of ５０50 mg KOH / g.
This is because the dispersion of the wax used in the present invention can be controlled, a preferable lamellar structure can be easily formed, and the dispersed particle diameter of the wax can be controlled.

When the acid value is less than 0.5 mgKOH / g, it is difficult to obtain this effect. When the acid value is more than 50 mgKOH / g, it is liable to be affected by environmental humidity, which is not preferable.

As the polymer component used for obtaining the above acid value, a polymer containing at least one of a carboxyl group, a carboxylic anhydride group and a carboxylic acid group is most preferred. For example, acrylic acid, methacrylic acid, α-ethylacrylic acid, acrylic acid such as crotonic acid and its α- or β-alkyl derivatives, phthalic acid, maleic acid, unsaturated dicarboxylic acids such as citraconic acid and its monoester derivatives or Maleic anhydride, etc.
A desired polymer is obtained by copolymerizing such a monomer alone or as a mixture with another monomer.

Of these, particularly preferred monomer components include maleic acid, maleic acid-half ester or maleic anhydride. Since maleic acid has a carboxyl group adjacent thereto, the effect of the acid group is more efficiently derived, which is suitable for increasing affinity with a transfer material such as paper and dispersing an acid-modified wax.

The polymer component used was a low molecular weight polymer component (molecular weight: 5 × 10 ⁴ in GPC chromatogram).
Value (A _VL ) and high molecular weight polymer (GPC
Region with a molecular weight of 5 × 10 ⁴ or more in the chromatogram)
It is preferred that the acid value (A _VH) and satisfies the following condition A _VL> A _VH.

When the acid value of the polymer component is A _VL > A _VH , the wax acts more on the low-molecular-weight polymer component than on the high-molecular-weight polymer component, and exhibits a low-temperature fixing property due to its plastic effect. .

Further, the polymer component preferably used in the present invention has a low molecular weight polymer having an acid value (A _VL ) of 10 to 35 m.
gKOH / g, and the acid value (A _VH ) of the high molecular weight polymer is 0.5 to 11 mgKOH / g, and the difference is in the range of 3 ≦ (A _VL −A _VH ) ≦ 27. It is preferred that

The low-temperature fixability is determined by the Tg of the low molecular weight polymer component.
The molecular weight distribution is affected by the addition of an acid component, and by increasing the acid value of the high molecular weight polymer component by 3 mgKOH / g or more, the same T
g and a resin composition having the same molecular weight distribution and an acid value out of the above range can lower the viscosity.

This is because the acid value of the high molecular weight polymer component is set at least 3 mg KOH / g lower than the acid value of the low molecular weight polymer component (acid value 0.5 to 11 mg KOH / g), whereby the low molecular weight polymer component Entanglement of the molecular chains of the high molecular weight polymer component and the wax to a certain extent,
It is considered that a sufficient release effect can be obtained because the viscosity is reduced on the low temperature side, the elastic properties are maintained on the high temperature side, and the wax has a certain domain diameter in the toner particles. As a result, low-temperature fixing in high-speed machines,
This leads to an improvement in development characteristics.

On the other hand, the difference in acid value is 27 mgKOH / g
If the ratio exceeds the above range, problems may occur in the mixing properties of the low molecular weight polymer component and the high molecular weight polymer component and the dispersibility of the wax component in the toner, and the offset resistance and the developability tend to decrease.

Further, the acid value of the low molecular weight polymer component is 10
When it is not less than mgKOH / g, the rising property of charging is good.

On the other hand, the acid value of the low molecular weight polymer component is 35 m
If it exceeds gKOH / g, the developability under high humidity tends to decrease.

An acid value of the high molecular weight polymer component is 0.5 mgK
If it is less than OH / g, the low molecular weight polymer component (acid value 1
(0-35 mgKOH / g) and miscibility with wax, resulting in reduced offset resistance and fogging.

When a polypropylene wax having the above-mentioned acid value is used, the wax has an acid value (A _VWAX ) satisfying the following conditions.

A _VL > A _VWAX , A _VWAX > 0 (mgKOH / g)

It has been found that, in the combination of the polymer component and the wax, it is preferable for the toner that the relationship between the acid value of the polypropylene wax and the acid value of the low molecular weight polymer satisfy the following conditions.

By controlling the compatibility between the wax and the polymer component, particularly the low molecular weight polymer, the low-temperature fixability and the offset resistance can be remarkably improved.

In the polymer component, when the acid value (A _VWAX ) of the wax component satisfies A _VL > A _VWAX with _respect to the acid value of the low molecular weight polymer, the fluidity and charge stability of the toner are longer. It turned out to be stable over time.

[0142] The acid value of the wax with respect to the acid value of the low molecular weight polymer, A _VL ≦ A _VWAX of Agego, offset resistance, toner chargeability under high humidity decreases.

More preferably, the acid value of the wax satisfies the following condition with respect to the acid value of the low molecular weight polymer component.

0.5 × A _VL > A _VWAX > 0.05 × A _VL

In the present invention, the acid value (JIS acid value) of the low molecular weight polymer component and the high molecular weight polymer component of the toner polymer component
Is determined by the following method.

<Preparation of each component> [Apparatus configuration] LC-908 (manufactured by Nippon Kagaku Kogyo Co., Ltd.) JRS-86 (company; repeat injector) JAR-2 (company; autosampler) FC-201 (Gilson; Hula cushion collector)

[Column Configuration] JAIGEL-1H to 5H diameter (20 mm × 600 m
m: Preparative column)

[Measurement conditions] Temperature: 40 ° C Solvent: THF Flow rate: 5 ml / min. Detector: RI

In the sample, additives other than the polymer component are separated in advance. As a preparative method, an elution time at which the molecular weight becomes 5 × 10 ⁴ is measured in advance, and before and after the elution time, the low molecular weight polymer component and the high molecular weight polymer component are separated. The solvent is removed from the sampled sample to obtain a sample for acid value measurement.

<Measurement of Acid Value> 1) A crushed sample of 0.1 to 0.2 g is precisely weighed, and its weight is defined as W (g).

2) Put the sample in a 20 cc Erlenmeyer flask,
10 cc of a mixed solution of toluene / ethanol (2: 1) is added and dissolved.

3) Add a few drops of an alcohol solution of phenolphthalein as an indicator.

4) The solution in the flask is titrated with a 0.1 N KOH alcohol solution using a burette. The amount of the KOH solution at this time is defined as S (ml). At the same time, a blank test was performed, and the amount of the KOH solution
(Ml).

5) The acid value is calculated by the following equation.

[0155]

(Equation 4)

Further, the acid value of the wax in the present invention was measured by the following measuring method.

<Separation of wax> Toner sample 0.5
Weighing about 1.0 g, and a cylindrical filter paper (for example, N
O. 86R) and toluene as a solvent.
Soxhlet extraction was performed for 20 hours using 100 ml, and the soluble components extracted by the solvent were evaporated.
Vacuum dry at 0 ° C. for several hours. After adding 20 ml of chloroform to the obtained extract and allowing it to stand for 1 hour, the extract is filtered through a membrane filter having a pore size of 0.45 μm and dried to obtain a wax component.

<Measurement of acid value>-Apparatus and instruments Direct reading balance Erlenmeyer flask (200 ml) Measuring cylinder (100 ml) Microburet (10 ml) Electric heater-Reagent Xylene dioxane N / 10 potassium hydroxide standard methanol solution 1% phenol cover Rain solution (indicator) Measurement method 1 to 1.5 g of wax is precisely weighed in an Erlenmeyer flask, 20 ml of xylene is added thereto, and the mixture is heated and dissolved. After dissolution, 20 ml of dioxane was added, and the solution was diluted with a standard methanol solution of N / 10 potassium hydroxide while the solution did not become cloudy or hazy.
Titrate as soon as possible with a% phenolphthalein solution as indicator. Perform a blank test at the same time. Calculation formula Acid value = [5.61 × (AB) × f] / S where A: Number of ml of N / 10 potassium hydroxide standard methanol solution required for this test B: N required for blank test Number of ml of / 10 potassium hydroxide standard methanol solution f: Factor of N / 10 potassium hydroxide standard methanol solution S: Sample (g)

In the present invention, the magnetic toner may optionally contain a charge control agent. In the case of a negatively chargeable toner, a negative charge controlling agent such as a metal complex salt of a monoazo dye or a metal complex salt of salicylic acid, alkylsalicylic acid, dialkylsalicylic acid or naphthoic acid is used. In the case of a positively chargeable toner, a positive charge control agent such as a nigrosine compound or an organic quaternary ammonium salt is used.

[0160] The content of the charge control agent is determined based on the toner binder resin 1
The amount is preferably 0.5 to 5 parts by weight, particularly preferably 0.2 to 3 parts by weight based on 00 parts by weight. If the content is too large, the fluidity of the toner deteriorates, and fogging easily occurs. On the other hand, if the amount is too small, it is difficult to obtain a sufficient charge amount.

In the present invention, the magnetic iron oxide is preferably added in an amount of 60 to 200 parts by weight, particularly preferably 70 to 150 parts by weight, based on 100 parts by weight of the toner binder resin. If the amount is less than 60 parts by weight, the toner transportability is insufficient, and the developer layer on the developer carrying member tends to have unevenness, which tends to cause image unevenness. There was a tendency for reduction to occur easily. Also, 200
When the amount is more than the weight part, the developer cannot be sufficiently charged, so that the image density tends to be reduced.

The magnetic toner of the present invention has environmental stability, charge stability, developability, fluidity and storage stability.
It is preferable that inorganic fine powder or hydrophobic inorganic fine powder is mixed. For example, fine silica powder, fine titanium oxide powder, or a hydrophobized product thereof may be used. They are preferably used alone or in combination.

As the fine silica powder, both a so-called dry method produced by vapor phase oxidation of a silicon halide or a so-called fumed silica and a so-called wet silica produced from water glass or the like can be used. But,
Surface and having less silanol groups inside, also Na ₂
Dry silica with less production residues such as O and SO ₃ ^2- is more preferable. In the case of fumed silica, it is also possible to obtain a composite fine powder of silica and another metal oxide by using another metal halide such as aluminum chloride and titanium chloride together with a silicon halide in the production process. , And also those.

Further, the silica fine powder is preferably subjected to a hydrophobic treatment. The hydrophobizing treatment is applied by chemically treating with an organosilicon-containing substance that reacts or physically adsorbs with the silica fine powder. As a preferable method, a method of treating a dry silica fine powder produced by vapor phase oxidation of a silicon halide with a silane coupling agent, or treating with a silane coupling agent and simultaneously with an organosilicon compound such as silicone oil. Is mentioned.

Examples of the silane coupling agent used in the hydrophobizing treatment include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, and allylphenyl. Dichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane,
Chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilyl acrylate, vinyldimethylacetoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyl Disiloxane, 1,3-diphenyltetramethyldisiloxane and dimethylpolysiloxane having 2 to 12 siloxane units per molecule and having hydroxyl groups bonded to silicon atoms at each terminal unit, one for each terminal unit, etc. Is mentioned.

Preferred silicone oils include 25
Those having a viscosity at 30 ° C. of 30 to 1000 centistokes are used, and for example, dimethyl silicone oil, methylphenyl silicone oil, α-methylstyrene-modified silicone oil, chromium phenyl silicone oil, fluorine-modified silicone oil and the like are particularly preferable.

As a method of treating the silicone oil, for example, a silica fine powder treated with a silane coupling agent and silicone oil may be directly mixed using a mixer such as a Henschel mixer, or a base fine powder may be used. A method of spraying silicone oil on the surface may be used. Alternatively, a method of dissolving or dispersing a silicone oil in an appropriate solvent, adding a silica fine powder, mixing and removing the solvent may be used.

The magnetic toner for developing electrostatic images of the present invention includes:
If necessary, an external additive other than silica fine powder or titanium oxide fine powder may be added. For example, there are resin fine particles and inorganic fine particles which function as a charge auxiliary agent, a conductivity imparting agent, a fluidity imparting agent, an anti-caking agent, a releasing agent at the time of fixing with a hot roll, a lubricant, an abrasive and the like. For example, lubricants such as Teflon, zinc stearate and polyvinylidene fluoride, among which polyvinylidene fluoride are preferred. Or cerium oxide, silicon carbide, abrasives such as strontium titanate,
Among them, strontium titanate is preferable. Or, for example, a fluidity imparting agent such as titanium oxide and aluminum oxide,
Among them, a hydrophobic substance is particularly preferable. A small amount of a caking inhibitor, a conductivity-imparting agent such as carbon black, zinc oxide, antimony oxide, or tin oxide, or white and black fine particles of opposite polarity can also be used as a developability improver. The resin fine particles, inorganic fine powder, or hydrophobic inorganic fine powder mixed with the toner are magnetic toner 1
0.1 to 5 parts by weight relative to 00 parts by weight (preferably,
0.1 to 3 parts by weight).

The magnetic toner for developing an electrostatic image of the present invention is prepared by sufficiently mixing the toner constituting materials with a mixer such as a ball mill, and then melting, kneading, and kneading using a hot kneader such as a heating roll, a kneader or an extruder. It can be produced by kneading, cooling, solidifying, and then pulverizing and strictly classifying.

Among these, in the melt-kneading step, a single-screw or twin-screw extrusion kneader is used because the toner constituent materials are well dispersed and continuous production is possible. In particular, a twin-screw extruder is preferable for controlling the state of the wax.

Generally, in a twin-screw extruder, two rotating shafts called paddles pass through a heating cylinder for keeping the temperature constant. The raw material is supplied from one end of a heating cylinder, heated, melted, kneaded by rotation of a paddle, and extruded from the other end. A vent hole whose main purpose is deaeration may be installed on the way.

FIG. 2 is a schematic view of an extrusion kneader preferably used in the present invention, and FIG. 3 is a schematic explanatory view of a paddle.

The cross section of the paddle 2 is a propeller-shaped one or a triangular-shaped one as shown in the figure, and is set out of phase so that one end always rotates as if rubbing the other. . This structure has a self-cleaning action of sending the kneaded material forward without adhering to the paddle and the cylinder wall. The rotation direction of the two paddles 2 may be the same or different, but the same direction is generally used.

The paddle 2 is roughly composed of two types of parts. One is a feed screw portion having a function of feeding the kneaded material forward while heating the kneaded material, and the other is almost effective in sending the kneaded material forward. This is a kneading section where the kneaded material stays and fills, and kneading is performed by changing the volume of compression and stretching with the rotation of the paddle.

In the case of kneading a soft toner composition intended for low-temperature fixing as in the present invention, there is almost no kneading at the screw portion, so that when the kneading portion is short, the kneaded material hardly stays. The raw materials constituting the toner composition are extruded before reaching a completely molten state.
This is a condition that greatly affects the wax dispersion state in the molten state and the higher-order structure of the wax. Therefore, when using a melt kneading device such as an extrusion kneader, a paddle configuration,
In particular, the length and arrangement of the kneading portion are important.

By providing two or more kneading portions as shown in FIG. 2, re-aggregation of each toner constituent material is prevented, and good dispersibility is obtained. Particularly total length of all the kneading portion of the total length of the paddle (L) [Ln; Ln = Ln 1
+ Ln ₂ + ...]] (Ln / L) of 15 to 35%, the shearing force applied to the kneaded material at the time of melt-kneading is optimized without impairing the dispersibility, and each toner component, particularly the wax, Reaggregation and cutting of the molecular chain of the binder resin are suppressed.
In particular, the ratio (Le / L) of the length Le of the kneading portion existing in the latter half of the paddle to the total length L of the paddle is 5-1.
This effect is remarkable when it is 0%. These paddle structures further affect the crystal structure and higher order structure of the wax in the dispersed phase, and facilitate the formation of the wax lamella structure found in the present invention. With these effects,
The developability and the high-temperature offset resistance can be improved.

In the case where the kneading portion is located at one place, the stay of the kneaded material is short, reaggregation in the screw portion is promoted, and poor dispersibility tends to occur. Further, if the kneading portion is lengthened to improve dispersibility, the shearing force applied during kneading increases, so that the resin temperature rises and promotes re-agglomeration of the wax, and a preferable crystal system can be obtained. Adversely affect the developability,
Breakage of the molecular chain is promoted, which may cause adverse effects such as reduction in high-temperature offset resistance. Particularly, the kneading portion existing in the latter half of the paddle is more important because it greatly affects the configuration of the kneaded material discharged from the outlet.

In order to obtain a preferable lamellar structure of the wax domain, the kneaded material discharged from the above device is further quenched by a blower-type cooling device which blows air toward the discharge port, and the kneaded material is cooled at 15 ° C. Below, preferably 1
It is preferable to perform rapid cooling with a cooling device set at 0 ° C. or lower (such as a cooling conveyor that keeps the temperature constant using cooling). This quenching can maintain the dispersed state and crystalline higher-order structure of the wax domain obtained by the kneading apparatus, and is effective in preventing a change in the wax dispersed state due to reaggregation or the like, which is preferable.

In the present invention, by providing the following features to the process cartridge, the toner accommodating section does not need to be formed in a substantially cylindrical shape. As a result, no packing occurred, the toner could be smoothly supplied to the sleeve, and a process cartridge free from the fading phenomenon in which an image was stripped off could be obtained.

The process cartridge is provided with a latent image holding member for holding an electrostatic charge image and at least one process means. Here, the process means
For example, there are a charging unit for charging the surface of the latent image holder, a developing unit for forming a toner image on the latent image holder, and a cleaning unit for cleaning toner remaining on the surface of the latent image holder. As shown in FIG. 4, the process cartridge of the present invention includes an electrophotographic photosensitive drum 7 serving as a latent image holding member.
A charging means 8, an exposing unit 9, a developing means 10, and a cleaning means 11 are arranged around, and these are integrated by covering them with a housing 12, and a shutter member 28 is further attached. Make up.

The photosensitive drum 7 constituting the process cartridge of the present invention is constituted by applying an organic photosensitive layer to the outer peripheral surface of a cylindrical aluminum drum base.
The photosensitive drum 7 is rotatably attached to the frame, and the driving force of a drive motor provided on the apparatus main body side is transmitted to a flange gear fixed to one longitudinal end of the photosensitive drum 7 as described later. The photosensitive drum 7 is rotated for an image forming operation.

The charging member constituting the process cartridge of the present invention is for uniformly charging the surface of the photosensitive drum 7, and in this embodiment, the charging roller 8 is rotatably mounted on the frame. Further, a so-called contact charging method is used. The charging roller 8 is formed by providing a conductive elastic layer on a metal roller shaft 8a, further providing a high-resistance elastic layer thereon, and further providing a protective film on the surface thereof. The conductive elastic layer is
It is made of an elastic rubber layer such as EPDM or NBR in which carbon is dispersed, and acts to guide a bias voltage supplied to the roller shaft 8a. The high-resistance elastic layer is made of urethane rubber or the like and contains a small amount of conductive fine powder as an example. Even when a pinhole of the photosensitive drum 7 or a charging roller having high conductivity is opposed, Photoconductor drum 7
To prevent a sharp drop in the bias voltage by limiting the leak current to the gate. The protective layer is made of N-methylmethoxylated nylon so that the composition of the conductive elastic layer or the high-resistance elastic layer does not touch the photoconductor drum 7 and deteriorate the surface of the photoconductor drum 7. Works. Then, the charging roller 8 is brought into contact with the photosensitive drum 7, and when forming an image, the charging roller 8 rotates following the rotation of the photosensitive drum 7. At this time, a DC voltage and an AC voltage are superimposed on the charging roller 8. To uniformly charge the surface of the photosensitive drum 7.

The exposing section 9 constituting the process cartridge of the present invention exposes the surface of the photosensitive drum 7 uniformly charged by the charging roller 8 to a light image radiated from the optical system, and exposes the surface of the drum 7 to the surface. This is for forming an electrostatic latent image, and constitutes an exposure section by providing an opening 9 for guiding the optical image on the upper surface of the cartridge frame.

The developing device 10 constituting the process cartridge of the present invention, as shown in FIG. 4, stores toner in a toner storage container 10a which is a toner storage portion, and sends out the toner as described later. A stirring member that stirs together is provided so as to be able to reciprocate. A non-rotating magnet 10b is provided inside the opening of the toner storage container 10a, and a developing sleeve 10c that forms a thin toner layer on the surface by rotating is provided with a minute gap from the photosensitive drum 7. . The developing sleeve 10c is formed by roughening the surface of an aluminum cylindrical member by sandblasting or the like, and applying a conductive paint dispersed with a pigment thereon. A toner layer is formed on the surface of the developing sleeve 10c. When the electrostatic latent image on the photosensitive drum 7 is developed by friction between the toner and the developing sleeve 10c, a sufficient triboelectric charge is obtained. A developing blade 10d is provided to regulate the thickness of the toner layer. Note that a stirring member for stirring and supplying the toner is provided in the toner storage container 10a, and the toner stirring configuration will be described later.

As shown in FIG. 4, the cleaning means 11 constituting the process cartridge of the present invention has a cleaning blade 11a for contacting the surface of the photosensitive drum 7 and scraping off the toner remaining on the drum 7.
A squeeze sheet 11b positioned below the blade 11a for scooping the scraped toner and weakly in contact with the surface of the photosensitive drum 7, and a waste toner reservoir 11c for storing the scooped waste toner It consists of:

The stirring means constituting the process cartridge of the present invention stirs the toner in the toner storage container 10a and sends it out to the developing sleeve 10c. As shown in FIG. 5, the stirring member is provided in the toner storage container 10a. 19 and a stirring arm 20 are provided. Stirring member 19
Is formed by connecting a plurality of bar-shaped members having a triangular cross section at predetermined intervals and integrating them. A shaft 19 a provided on the tip side of the stirring member 19 is connected to a hole 20 of the stirring arm 20.
a. The stirring arm 20 is rotatably supported on the side walls 10a ₁ and 10a ₂ of the toner container 10a so as to be rotatable around a rotation shaft 20c.
Extend outwardly from the side wall 10a ₂ of 0a, at its front end a drive arm 20b is are formed integrally. The outer side wall 10a ₂ of the toner storing container 10a Yes in stirring gear 21 is provided to rotate around a rotation shaft 21a with the rotation of the photosensitive drum 7. The rotating shaft 2 is provided on the side surface of the stirring gear 21.
Eccentric dowel 21b which is eccentric from 1a is is provided with, fitted in the long hole 20b ₁ of the driving arm 20b. When the stirring gear 21 rotates by receiving the drive transmission from the same drive source as the photosensitive drum 7 rotates, the stirring arm 20
mainly c, and reciprocally rotated in the arrow X direction in FIG. 5, the stirring member 19 along the bottom wall 10a ₃ of the toner storing container 10a, the toner agglomeration and uneven distribution reciprocally moved in the arrow Y direction in FIG. 5 To prevent The bottom wall 10a ₃ of the toner accommodating container 10a, as easily toner is fed to the developing sleeve 10c, Yes formed on the slope where the developing sleeve 10c side drops, the stirring member 19 along the bottom surface of the toner storing container 10a Reciprocating in the direction of arrow Y, the toner is fed in the direction of the developing sleeve 10c.

[0187]

EXAMPLES The present invention will be described below in more detail with reference to production examples and examples. In the examples, "part" and "%"
Means “parts by weight” and “% by weight” unless otherwise specified.

Production of Magnetic Iron Oxide [Production Example 1] Sodium silicate was added to an aqueous ferrous sulfate solution so that the content ratio of silicon element to iron element was 1.6%. 0.6% of zinc element
After adding zinc sulfate so as to obtain, an aqueous solution containing ferrous hydroxide was prepared by mixing 1.0 to 1.1 equivalents of a sodium hydroxide solution with respect to iron ions.

The pH of the aqueous solution is adjusted to pH 7 to 10 (for example, p
H9), while blowing air, 80 to 90
An oxidation reaction was performed at a temperature of 0 ° C. to prepare a slurry liquid for generating seed crystals.

Next, an aqueous solution of ferrous sulfate was added to the slurry so that the amount thereof became 0.9 to 1.2 equivalents relative to the initial alkali amount (sodium component of sodium silicate and sodium component of sodium hydroxide). While maintaining the pH of the solution at 6 to 10 (eg, pH 8), the oxidation reaction was promoted while blowing air, the pH was adjusted at the end of the oxidation reaction, and the silicate component and the zinc component were unevenly distributed on the surface of the magnetic iron oxide particles. . The generated magnetic iron oxide particles are washed by a conventional method, filtered,
After drying, the aggregated product was subjected to a crushing treatment to obtain magnetic iron oxide A.

Table 1 shows the relationship and characteristics of the amounts of iron, silicon and other metal elements dissolved in the obtained magnetic iron oxide.

[Production Examples 2 to 6] Sodium silicate addition amount,
Magnetic iron oxides B to F having the characteristics shown in Table 1 were obtained in the same manner as in Production Example 1, except that the addition amount of the other metal salt was changed as shown in Table 1.

[Comparative Production Example 1] A magnetic iron oxide a having the properties shown in Table 1 was obtained in the same manner as in Production Example 1 except that sodium silicate and zinc sulfate were not added.

[Comparative Production Example 2] To 100 parts of the magnetic iron oxide obtained in Comparative Production Example 1, 0.7 part of silicic acid fine powder was mixed with a Henschel mixer and had the characteristics shown in Table 1. Magnetic iron oxide b was obtained.

[Comparative Production Examples 3 to 7] Tables 1 and 2 were prepared in the same manner as in Production Example 1 except that the amounts of sodium silicate and other metal salts were changed as shown in Table 1. Magnetic iron oxides c to g having the characteristics shown were obtained.

[0196]

[Table 1]

Example 1 As a low molecular weight polymer, styrene-butyl acrylate synthesized by a known method was used.
Monobutyl maleate copolymer (L1) (peak molecular weight 10300, acid value 28 mgKOH / g) was used as a high molecular weight polymer by a known method, and styrene-butyl acrylate-monobutyl maleate copolymer (H1) (peak molecular weight 1.02 million and an acid value of 6 mgKOH / g). After dissolving 70 parts of the low molecular weight polymer (L1) and 30 parts of the high molecular weight polymer (H1) in 100 parts of refluxing xylene, the organic solvent is distilled off, and the obtained resin is cooled and solidified. It was pulverized to obtain a resin raw material for toner. Table 2 shows the physical properties of the resin. 100 parts of the above resin copolymer for toner (acid value 21 mg KOH / g) 95 parts of magnetic iron oxide particles A of Production Example 1 2 parts of negative charge control agent (metal complex type monoazo compound) 2 parts maleic anhydride-modified propylene- Ethylene copolymer (see Table 2) 6 parts (ethylene component 6%, acid value 11 mgKOH / g, DSC peak 128 ° C)

The above mixture was melt-kneaded with a twin-screw extruder heated to 140 ° C. As a twin-screw extruder, the paddle length L is 3000 mm, a kneading section exists in two places of the paddle, and a kneading section closer to the raw material mixture feed (entrance) side (existing in the first half). Length L _n1 is 600 mm, and length L _{n2 of the} kneading portion closer to the exit side (existing in the rear half) =
L _e is a configuration of the paddle is 200mm. 15 m ³ / min under standard conditions (0 ° C., 101.3 kPa)
A blower-type cooling device that blows at the air volume of the kneading device is installed at the discharge section of the kneading apparatus, and the kneaded material is rapidly cooled by blowing cold air having a cold air temperature set at 10 ° C. onto the kneaded substance discharged from the discharging section of the kneading apparatus. The kneaded material was rapidly cooled while being transported on a cooling conveyor maintained at a temperature of 15 ° C. by passing cooling water through the conveyor. The cooled kneaded material was roughly pulverized with a hammer mill and further finely pulverized with a jet mill, and the obtained finely pulverized powder was classified with a fixed wall air classifier to produce a classified powder. Further, the obtained classified powder is strictly classified and removed by a multi-segmentation classifier utilizing a Coanda effect (an elbow jet classifier manufactured by Nittetsu Mining Co., Ltd.) at the same time to remove the weight average particle diameter (D ₄ ) 6.7 μm, volume average particle size (D ₁ ) 5.
A classified powder having a content of 0.2% of magnetic toner particles having a particle diameter of 25 μm and a particle diameter of 12.7 μm or more and a content of magnetic toner particles having a particle diameter of less than 4.0 μm was 0.2% was obtained.

100 parts of the classified powder was treated with dimethyldichlorosilane, and then treated with hexamethyldisilazane.
Next, 1.2 parts of hydrophobic silica fine powder (BET 300 m ² / g) treated with dimethyl silicone oil, and 0.08 parts of styrene-acrylic fine particles (average particle diameter 0.05 μm) obtained by soap-free polymerization were added. Was mixed with a Henschel mixer to obtain a toner.

When a cross section of the toner was observed with a transmission electron microscope, a wax phase having a lamellar structure having a layer thickness of 0.6 μm was observed.

The particle size distribution of the toner of the present invention was measured using a Coulter Counter TA-II or a Coulter Multisizer (manufactured by Coulter Inc.). As the electrolyte, a 1% aqueous NaCl solution was prepared using primary sodium chloride.
For example, ISOTON R-II (manufactured by Coulter Scientific Japan) can be used. As a measurement method, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersing agent to 100 to 150 ml of the electrolytic aqueous solution, and a measurement sample is further added to 2 to 20 ml.
Add mg. The electrolytic solution in which the sample is suspended is subjected to dispersion treatment for about 1 to 3 minutes by an ultrasonic disperser, and the volume and the number of toner particles having a size of 2 μm or more are measured by using the measuring device using a 100 μm aperture as the aperture. Distribution was calculated.

The weight-average particle diameter (D ₄ ) and the volume-average particle diameter (D ₄ ) obtained from the volume distribution according to the present invention are based on weight.
v) (the median value of each channel is set as a representative value for each channel), particle diameter 12.7 μm obtained from volume distribution
The content of the magnetic toner particles having a particle diameter of less than 4.0 μm determined from the above ratio and number distribution was determined.

The toner prepared in Example 1 was evaluated by the following method.

A process cartridge shown in FIG. 4 is filled with toner, and a commercially available laser beam printer L is used.
Attach to BP-430 (Canon), 8 sheets (A4) /
1 minute print speed, low temperature and low humidity (15 ° C, 10% R
H) and a durability test of 4000 sheets were performed in a high-temperature, high-humidity (32.5 ° C., 80% RH) environment. Table 3 shows the obtained image evaluation results.

The evaluation method is as follows.

Image Density Evaluation was made by maintaining the image density at the end of 40,000 sheets of ordinary paper for copying machines (75 g / m ² ). The image density was measured by using a "Macbeth reflection densitometer" (manufactured by Macbeth Co., Ltd.) with respect to a printout image of a white background portion having a document density of 0.00.

The whiteness of the transfer paper measured by a fog reflectometer (manufactured by Tokyo Denshoku Co., Ltd.) and low temperature and low humidity (15 ° C./10% RH)
Under the environment, fog was calculated from a comparison between the whiteness of the second surface of the transfer paper after printing the double-sided solid white after 4000 sheets of durability image formation.

Fixability The fixability is determined by applying a load of 50 g / cm ² to a fixed image printed and fixed in a low-temperature and low-humidity environment (15 ° C./10% RH), rubbing the fixed image with soft thin paper, Evaluation was made based on the reduction rate (%) of the image density before and after rubbing. As the test paper, plain paper for a copying machine (90 g / m ² ) in which the toner is fixed was used. A (excellent): less than 5% B (good): 5% to 10% C (acceptable): 10% to 20% D (impossible): over 20%

Offset Resistance The offset resistance was evaluated by printing out a sample image having an image area ratio of about 5% and evaluating the degree of stain on the image. As a test paper, plain paper for copying machines (64 g / m ² ) was used. A: not generated B: hardly generated C: generated a small amount of dirt D: generated dirt

Occurrence of Fading During the endurance of 4000 sheets, an image of a solid black image was formed at a rate of 1 out of 100 sheets, and whether or not fading caused by toner supply failure occurred on the image was observed.

[Examples 2 to 6] Magnetic iron oxides B to F shown in Table 1 were used as magnetic iron oxides, waxes shown in Table 2 were used as waxes, and resin compositions shown in Table 2 were used as resins. Example 2 was performed in the same manner as Example 1 except that
To 5 were obtained. The obtained toner was evaluated in the same manner as in Example 1. Table 3 shows the evaluation results.

Further, when the cross sections of these toners were observed with a transmission electron microscope, wax phases each having a lamellar structure having a layer thickness shown in Table 2 were observed.

[Comparative Example 1] The kneading and melting step was carried out to a bread inner size of 15.
A toner was obtained in the same manner as in Example 1 except that a batch-type kneader of 00 mm × 1330 mm × 1150 mm was used, and that an unmodified polypropylene wax (ethylene component: less than 1%, DSC peak: 137 ° C) was used as a wax component. Was. The obtained toner was evaluated in the same manner as in Example 1. Table 3 shows the evaluation results.

When a cross section of the toner was observed with a transmission electron microscope, no clear lamellar structure was observed.

[Comparative Examples 2 to 8] Magnetic iron oxides a to g shown in Table 1 were used as magnetic iron oxides, waxes shown in Table 2 were used as waxes, and resin compositions shown in Table 2 were used as resins. Comparative Example 2 in the same manner as in Example 1 except that
To 8 were obtained. The obtained toner was evaluated in the same manner as in Example 1. Table 3 shows the evaluation results.

Table 2 shows the results of observing the cross sections of these toners with a transmission electron microscope.

[0219]

[Table 2]

[0218]

[Table 3]

[0219]

As described above, the magnetic toner and the process cartridge of the present invention provide a high-quality image for a long period of time in any environment, and satisfy the fixing performance and the anti-offset performance to a high degree. Even if the toner storage section in the cartridge has an irregular shape,
A magnetic toner and a process cartridge which can supply toner smoothly and do not cause fading due to packing.

[Brief description of the drawings]

FIG. 1 is a view showing a lamella structure formed in a dispersed phase of a wax in a toner.

FIG. 2 is a schematic diagram of a kneading apparatus suitable for producing the toner of the present invention.

FIG. 3 is a detailed view of a paddle of the kneading apparatus of FIG. 2;

FIG. 4 is an explanatory diagram of a configuration of a process cartridge.

FIG. 5 is a perspective view illustrating a configuration of a toner storage unit and a stirring unit for stirring and supplying the toner.

[Explanation of symbols]

1 heating cylinder 2 paddle 3 vent holes 4 supply port 5 extrusion port 6 Ingredients hopper 102 recording medium 104 transferring means 7 the photosensitive drum 8 charging means 8a roller shaft 9 exposed portion 10 a developing unit 10a toner storing container 10a _1, 10a ₂ side walls 10a ₃ bottom wall 10a ₄ top wall 10a ₅ recess 10a ₆ , 10a ₇ light transmitting window 10a ₈ toner filling opening 10b magnet 10c developing sleeve 10d developing blade 11 cleaning means 11a cleaning blade 11b squeeze sheet 11d waste toner reservoir 12 housing 12a upper frame 12b sill member 12c lid member 12c ₁ groove 19 stirring member 19a shaft 19b opening 19c U-shaped groove 19c _1, 19c ₂ sliding surface 19d ribs 20 agitating arm 20a hole 20b drive arm 20b ₁ hole 20c pivot shaft 21 stirred formate 21a rotational shaft 21b eccentric dowel 21b ₁ long holes 22a emitting element 22b receiving element 23a, 23b, light-transmitting member 23a _1, 23b ₁ light transmitting portion 23a _2, 23b ₂ flange portion 23a _3, 23b ₃ interface 24 wiper blade 24a center Portion 24b, 24c Tip side 24d Opening 25 Wiper arm 25a, 25b Tip side 25c Slit 25d Rotating shaft 25e Drive shaft 26 Bearing 27 Stopper 28 Shutter member 28a Shutter arm

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuma Sato 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (38)

[Claims] 1. A magnetic toner for developing an electrostatic charge image having toner particles containing at least a binder resin, wax and magnetic iron oxide, wherein the wax is contained in a wax domain observed by a transmission electron microscope in the toner. 0.3 to 2.0μ
m having a lamellar structure, and the magnetic iron oxide is composed of Mn, Zn, N
i, Cu, Co, Cr, Cd, Al, Sn, and one or more metal elements selected from the group consisting of Mg.
2 to 4.0% by weight, and further contains 0.1% of silicon element.
2 to 0.8% by weight, wherein the magnetic iron oxide contains the silicon element content B _Si present when the iron element dissolution rate of the magnetic iron oxide is up to 20% by weight and the magnetic iron oxide is present in the magnetic iron oxide. Ratio of the total silicon element to the _Si content (B
_Si / A _Si ) × 100 is 45 to 85%, and the ratio of the content C _Si of the silicon element and the content A _Si of the magnetic iron oxide in which the iron element dissolution rate of the magnetic iron oxide is up to 10% by weight ( C _Si / A
_Si ) A magnetic toner for developing electrostatic images, wherein x100 is 35 to 70%. 2. The magnetic iron oxide according to claim 1, wherein Mn, Zn, Ni, and Mn are present when the iron element dissolution rate of the magnetic iron oxide is up to 20% by weight.
Content B of one or more metal elements selected from the group consisting of Cu, Co, Cr, Cd, Al, Sn and Mg
_Metal and the ratio of the content A _Metal of the metal group element present in the magnetic iron oxide _{(B Metal / A Metal) ×} 100
2. The magnetic toner according to claim 1, wherein the ratio is 40 to 100%. 3. The magnetic iron oxide according to claim 1, wherein M is based on iron element.
n element content of 0.7 to 2.0% by weight, the Mn element content B _Mn existing when the iron element dissolution rate of the magnetic iron oxide is up to 20% by weight, and the total amount of Mn element present in the magnetic iron oxide The ratio (B _Mn / A _Mn ) × 100 of Mn element content to A _Mn is 50 to 9
The magnetic toner according to claim 1, wherein the magnetic toner is 0%. 4. The magnetic iron oxide according to claim 1, wherein Z
The n elements containing 0.2 to 0.8 wt%, and the content B _Zn of Zn element iron element dissolution ratio of the magnetic iron oxide is present in up to 20% by weight, the total present in the magnetic iron oxide the ratio between the content a _Zn of Zn element _{(B Zn / a Zn) ×} 100 is 40 to 1
The magnetic toner for developing an electrostatic image according to claim 1, wherein the content of the magnetic toner is 00%. 5. The magnetic iron oxide according to claim 1, wherein C is
the Cu element content B _Cu containing 0.01 to 0.8% by weight of the u element, and the iron element dissolution rate of the magnetic iron oxide is up to 10% by weight; 3. The magnetic toner according to claim 1, wherein a ratio (B _Cu / A _Cu ) × 100 of the Cu element content to A _Cu is 70 to 100%. 6. The magnetic iron oxide according to claim 1, wherein said magnetic iron oxide is N
The i element containing 0.1 to 0.6 wt%, and the content B _Ni of Ni element iron element dissolution ratio of the magnetic iron oxide is present in up to 20% by weight, the total present in the magnetic iron oxide Ni element content A _Ni ratio (B _Ni / A _Ni ) × 100 is 40 to 1
The magnetic toner for developing an electrostatic image according to claim 1, wherein the content of the magnetic toner is 00%. 7. The magnetic toner for developing electrostatic images according to claim 1, wherein the wax has an acid value of 1 to 15 mgKOH / g. 8. A differential scanning calorimeter (DSC) of the wax.
The endothermic peak derived from the melting point measured by
8. The magnetic toner for developing an electrostatic image according to claim 1, wherein the magnetic toner is present in a temperature range of 0 to 150 [deg.] C. 9. The wax according to claim 1, wherein the wax contains an ethylene-propylene copolymer, and the ethylene-propylene copolymer contains 3 to 20% by weight of an ethylene component. The magnetic toner for developing an electrostatic image according to any one of the above. 10. The wax according to claim 1, wherein the wax contains an ethylene-propylene copolymer, and the ethylene-propylene copolymer contains 3 to 10% by weight of an ethylene component. The magnetic toner for developing an electrostatic image according to any one of the above. 11. The method according to claim 1, wherein the wax is modified with an acid monomer selected from at least one of maleic acid, maleic acid half ester and maleic anhydride. The magnetic toner for developing an electrostatic image according to the above. 12. The polymer component of the binder resin contains substantially no THF-insoluble matter, and has at least a molecular weight of 3 × 10 ³ in a molecular weight distribution measured by GPC (gel permeation chromatography) of a THF-soluble matter. A main peak in the region of 〜3 × 10 ⁴ and a molecular weight of 1 × 10 ⁵ -3 ×
12. The magnetic toner for developing an electrostatic image according to claim 1, wherein the magnetic toner has a subpeak or a shoulder in a region of 10 < ⁶ >. 13. The polymer component of the binder resin is 0.5 to 0.5.
The magnetic toner for developing an electrostatic image according to claim 12, having an acid value of 50 mgKOH / g. 14. The polymer component of the binder resin has an acid value (A _VL ) of a low molecular weight polymer in a region having a molecular weight of less than 5 × 10 ^{4 in} a molecular weight distribution measured by GPC and a molecular weight of 5 in a molecular weight distribution measured by GPC. _14. The electrostatic image developing method according to claim 12, wherein the acid value (A _VH ) of the high molecular weight polymer in the region of × 10 ⁴ or more satisfies the following condition: A _VL > A _VH . Magnetic toner. 15. The method according to claim 15, wherein the acid component of the polymer of the binder resin is modified with an acid monomer selected from at least one of maleic acid, maleic acid half ester and maleic anhydride. The magnetic toner for developing an electrostatic image according to claim 12. 16. The low molecular weight polymer of the polymer component has an acid value (A _VL ) of 10 to 35 mg KOH / g, and the high molecular weight polymer has an acid value (A _VH ) of 0.5 to 11 mg KOH / g. 16. The magnetic toner for developing an electrostatic image according to claim 12, wherein the relationship of the difference is 3 ≦ (A _VL −A _VH ) ≦ 27. 17. The electrostatic image according to claim 12, wherein the acid value (A _VWAX ) of the wax satisfies the following condition with _{respect to} the acid value of the low molecular weight polymer component. Magnetic toner for development. 0.5 × A _VL > A _VWAX > 0.05 × A _VL 18. A toner produced by a production method including a melt-kneading step of producing a kneaded product by melt-kneading a raw material mixture by a kneading means, wherein the kneading means is an extrusion kneading machine. , Having two or more kneading parts in the paddle, and the total length Ln of all kneading parts
And the ratio of the total length L of the paddle (Ln / L) is 15 to 35%
The magnetic toner for developing an electrostatic image according to claim 1, wherein the magnetic toner is manufactured by a manufacturing method according to claim 1. 19. The ratio (Le / L / L) of the length Le of the kneading portion present in the rear half portion of the paddle to the total length L of the paddle.
19. The magnetic toner according to claim 18, wherein L) is 5 to 10%. 20. A process cartridge detachably mounted to an image forming apparatus main body, the process cartridge comprising: a latent image holding member for holding an electrostatic image; A charging member for charging the latent image holding member by applying a voltage; and a toner for developing a static charge image held on the latent image holding member to form a toner image. The developing device includes a toner storage unit that stores the toner, and a stirring unit that can reciprocate to stir and supply the toner stored in the toner storage unit. The toner has toner particles containing at least a binder resin, a wax and a magnetic iron oxide, and the wax has a wax domain observed in the toner by a transmission electron microscope. To 0.3 to 2.0μ
m having a lamellar structure, and the magnetic iron oxide is composed of Mn, Zn, N
i, Cu, Co, Cr, Cd, Al, Sn, and one or more metal elements selected from the group consisting of Mg.
2 to 4.0% by weight, and further contains 0.1% of silicon element.
2 to 0.8% by weight, wherein the magnetic iron oxide contains the silicon element content B _Si present when the iron element dissolution rate of the magnetic iron oxide is up to 20% by weight and the magnetic iron oxide is present in the magnetic iron oxide. Ratio of the total silicon element to the _Si content (B
_Si / A _Si ) × 100 is 45 to 85%, and the ratio of the content C _Si of the silicon element and the content A _Si of the magnetic iron oxide in which the iron element dissolution rate of the magnetic iron oxide is up to 10% by weight ( C _Si / A
_Si ) A process cartridge wherein x100 is 35 to 70%. 21. The magnetic iron oxide according to claim 1, wherein the magnetic iron oxide has an iron element solubility of up to 20% by weight.
i, the content of one or more metal elements selected from the group consisting of Cu, Co, Cr, Cd, Al, Sn, and Mg, B _Metal, and the content, A, of the metal group elements present in the magnetic iron oxide _Metal and ratio _{(B Metal / a Metal) ×} 1
21. The process cartridge according to claim 20, wherein 00 is 40 to 100%. 22. The magnetic iron oxide contains 0.7 to 2.0% by weight of Mn element based on iron element, and the dissolution rate of iron element of the magnetic iron oxide is up to 20% by weight. 21. The ratio (B _Mn / A _Mn ) × 100 of the content B _Mn of the content of iron to the content A _Mn of all Mn elements present in the magnetic iron oxide is 50 to 90%. Or the process cartridge according to 21. 23. The magnetic iron oxide according to claim 1, wherein said magnetic iron oxide contains 0.2 to 0.8% by weight of Zn based on iron, and said magnetic iron oxide has a solubility of iron up to 20% by weight. 21. The ratio (B _Zn / A _Zn ) × 100 of the content B _Zn of the content and the content A _Zn of all Zn elements present in the magnetic iron oxide is 40 to 100%. Or the process cartridge according to 21. 24. The magnetic iron oxide according to claim 1, wherein said magnetic iron oxide contains 0.01 to 0.8% by weight of Cu based on iron, and said magnetic iron oxide has a solubility of iron up to 10% by weight. 21. The ratio (B _Cu / A _Cu ) × 100 of the content B _Cu of the content of _Cu to the content A _Cu of all Cu elements present in the magnetic iron oxide is 70 to 100%. Or 21
The process cartridge according to 1. 25. The magnetic iron oxide according to claim 1, wherein the magnetic iron oxide is based on iron element.
Containing 0.1 to 0.6% by weight of Ni element;
Ni element present when iron dissolution rate of iron is up to 20% by weight
Content B of_NiAnd all Ni elements present in the magnetic iron oxide
Content A of_Ni And the ratio (B_Ni/ A_Ni) X 100 is 40 or more
22. The method according to claim 20, which is 100%.
The process cartridge as described. 26. The wax according to claim 1, wherein the wax is 1 to 15 mgKOH / g.
The process cartridge according to any one of claims 20 to 25, having an acid value of: 27. A differential scanning calorimeter (DS) of the wax.
The endothermic peak derived from the melting point measured by C)
The process cartridge according to any one of claims 20 to 26, wherein the temperature is in a range of 110 to 150 ° C. 28. The wax according to claim 20, wherein the wax contains an ethylene-propylene copolymer, and the ethylene-propylene copolymer contains 3 to 20% by weight of an ethylene component. The process cartridge according to any one of the above. 29. The method according to claim 20, wherein the wax contains an ethylene-propylene copolymer, and the ethylene-propylene copolymer contains 3 to 10% by weight of an ethylene component. The process cartridge according to any one of the above. 30. The wax according to claim 20, wherein the wax is modified with an acid monomer selected from at least one of maleic acid, maleic acid half ester, and maleic anhydride. The process cartridge as described. 31. The polymer component of the binder resin contains substantially no THF-insoluble matter, and has at least a molecular weight of 3 × 10 ³ in a molecular weight distribution measured by GPC (gel permeation chromatography) of a THF-soluble matter. A main peak in the region of 〜3 × 10 ⁴ and a molecular weight of 1 × 10 ⁵ -3 ×
The process cartridge according to any one of claims 20 to 30, characterized in that in the region of ¹⁰⁶ with a sub-peak or shoulder. 32. The polymer component of the binder resin is 0.5 to 0.5.
The process cartridge according to claim 31, wherein the process cartridge has an acid value of 50 mgKOH / g. 33. The polymer component of the binder resin has an acid value (A _VL ) of a low molecular weight polymer having a molecular weight of less than 5 × 10 ^{4 in the} molecular weight distribution measured by GPC and a molecular weight of 5 in the molecular weight distribution measured by GPC. _33. The process cartridge according to claim 31, wherein the acid value (A _VH ) of the high molecular weight polymer in the region of × 10 ⁴ or more satisfies the following condition: A _VL > A _VH . 34. The method according to claim 34, wherein the acid component of the polymer of the binder resin is modified with an acid monomer selected from at least one of maleic acid, maleic acid half ester and maleic anhydride. The process cartridge according to any one of claims 31 to 33. 35. The low molecular weight polymer of the polymer component has an acid value (A _VL ) of 10 to 35 mg KOH / g, and the high molecular weight polymer has an acid value (A _VH ) of 0.5 to 11 mg KOH / g. The process cartridge according to any one of claims 31 to 34, wherein there is a relation of 3 ≦ (A _VL −A _VH ) ≦ 27. 36. The process cartridge according to claim 31, wherein the acid value (A _VWAX ) of the wax satisfies the following condition with _{respect to} the acid value of the low molecular weight polymer component. 0.5 × A _VL > A _VWAX > 0.05 × A _VL 37. A toner produced by a production method including a melt-kneading step of producing a kneaded product by melt-kneading a raw material mixture by a kneading means, wherein the kneading means is an extrusion kneading machine. , Having two or more kneading parts in the paddle, and the total length Ln of all kneading parts
And the ratio of the total length L of the paddle (Ln / L) is 15 to 35%
37. The process cartridge according to claim 20, wherein the process cartridge is manufactured by the following manufacturing method. 38. The ratio of the length Le of the kneading portion present in the latter half of the paddle to the total length L of the paddle (Le /
The process cartridge according to claim 37, wherein the process cartridge is manufactured by a manufacturing method in which L) is 5 to 10%.