JPH02148044A - Magnetic toner and developing method using the toner - Google Patents

Abstract

PURPOSE:To stabilize electric chargeability by using a magnetic material having adsorbed a specified compound to the surface and forming a magnetic toner having a specified particle diameter distribution. CONSTITUTION:The magnetic toner is composed essentially of a binder resin and the magnetic material having adsorbed a compound of formula I or II or a mixture of them, and this toner has the following particle diameter distribution: The particles of <=5mum diameter amounting to >=12 number %; the particles of 8-12.7mum diameter amounting to <=33 number %; the particles of >=16mum diameter amounting to <=2.0 volume %; and the toner having an average particle diameter of 4-10mum, thus permitting stable chargeability to be obtained. In formulae I and II, R<1> is 6-24C alkyl or alkenyl; R<2> is 1-24C alkyl or alkenyl; R<3> is 1-8C alkyl; R<4> is aralkyl or 1-8C alkyl; and X<-> is halide ion.

Description

Detailed Description of the Invention [Field of Application in Industry-1-] The present invention relates to a toner for developing electrostatic latent images in electrophotography, electrostatic recording, etc., and a developing method using the toner.

[Prior Art] Conventionally, two-component toners using a carrier and one-component toners containing a magnetic component are known as dry toners used in electrophotography and the like.

- component magnetic toner has the advantage that the developing device can be simplified,
It has been widely used because it is easy to maintain.

Generally, the following method is used to produce magnetic toner.

The magnetic material, binder resin, charge control agent, etc. are mixed uniformly using a mixer such as a ball mill or Henschel mixer, and then melted and kneaded using a kneader such as a roll mill, extorter, or kneader cap to thoroughly mix each component. to be dispersed. Thereafter, it is finely pulverized using a jet mill or the like, and then classified using an air classifier or the like to obtain a magnetic toner.

In addition, in order to improve the dispersion of the magnetic material in the binder resin,
Methods have been proposed in which the surface of a magnetic material is treated with various substances for the purpose of increasing the compatibility of the magnetic material with an organic material.

For example, JP-A-53137-148 discloses fatty acids and their derivatives, JP-A-53-81125 discloses polymeric materials, JP-A-54-127328 discloses silane coupling agents, 55-28019 discloses a titanium coupling agent. These materials are excellent in improving compatibility.

However, in magnetic toner, a magnetic substance is exposed to some extent on the surface of the toner and discharges excessively charged charges, thereby playing a role in adjusting the amount of charge to an appropriate level. Therefore, when using a magnetic material treated as described above, the hydrophilicity of the surface of the magnetic material is lost and the polarization increases, inhibiting the release of charge, causing the toner to become overcharged, resulting in image 1-
may splatter and cause roughness. In addition, there is a possibility that the reflection force on the developing sleeve becomes strong, causing excessive deterioration or unevenness in the sleeve coat. This phenomenon becomes more noticeable under low humidity conditions or in high-speed machines, and it is inevitable that image defects will occur.

On the other hand, various magnetic materials are manufactured in order to obtain the desired magnetic properties, electrical properties, and powder properties, but some of them do not release enough charge, and compared to the above example, There are many magnetic materials that cause image defects, albeit to a lesser extent.

In addition, as a method for improving the dispersion of magnetic materials, JP-A-58
-125749, JP 59-126544, JP 59-125747, JP 511-
125748, JP 59-125748, JP 59125750, JP 81-593
No. 49 discloses a surfactant. These materials are excellent in improving compatibility, have stable charging properties even under low humidity, and give good images. However,
Although it is moisture resistant in the sense that it does not undergo irreversible changes under high humidity, it tends to release more charge and often causes a low concentration f.

On the other hand, in recent years, as image forming apparatuses such as electrophotographic copying machines have become widespread, their uses have expanded to a wide variety of uses, and demands on their image quality have become stricter. When copying images such as general documents and books, it is required to reproduce extremely finely and faithfully, without being crushed or cut off, even down to the minute characters. Particularly, when the latent image on the photoreceptor-L of the image forming apparatus is a line image of less than looILm, fine line reproducibility is generally poor, and the line image clarity is still not sufficient. In recent years, in image forming devices such as electrophotographic printers that use digital image signals, latent images are formed by dots with a constant potential.
Solid areas, halftone areas, and light areas are expressed by changing the dot density. However, when the toner particles do not adhere to the dots faithfully and the toner particles protrude from the dots, the tonality of the l/toner image corresponds to the ratio of the dot density of 1W between the black part and the peak part of the digital latent image. The problem is that it cannot be done. Furthermore, when improving the resolution by reducing the dot size in order to whiten the image quality, it becomes more difficult to reproduce the latent image formed from minute dots, resulting in poor resolution and gradation. , the image tends to lack sharpness.

In addition, although the image quality is good initially, as copying or printing continues, the image quality may deteriorate. This phenomenon is thought to occur because, as copying or printing continues, only toner particles that are easily developed are consumed first, and toner particles that are less developable accumulate and remain in the developing machine.

Up to now, several developers have been proposed for the purpose of improving image quality. Japanese Patent Publication No. 51-324
No. 4 proposes a non-magnetic toner intended to improve image quality by regulating particle size distribution. The toner mainly has a particle size of 8 to 12 μm, which is relatively coarse, and according to the studies of the present inventors, it is difficult to uniformly "glue" the latent image with this particle size. , and 5μm
The particle size distribution is broad due to the characteristics that the particle size is 30% by number or less and the particle size of 20 μm or more is 5% by number or less, which also tends to reduce uniformity and properties. In order to form clear images using I-toner, which has coarse toner particles and a broad particle size distribution, it is necessary to overlap the toner particles thickly to fill the gaps between the toner particles. It is necessary to reduce the apparent image density by -L,
Another problem is that the amount of toner consumption required to produce a predetermined image density increases.

Furthermore, in Japanese Patent Application Laid-Open No. 72054/1984, a non-magnetic toner having a sharper distribution than the former is proposed, but the size of particles with intermediate weight is 8.5 to 11.0I1.
There is still room for improvement as a high-resolution toner with a coarse grain size of m.

In JP-A No. 58-128437, the average particle size is 6 to
A non-magnetic toner has been proposed in which the particle size is 10 μm and the maximum number of particles is 5 to 8, but the number of particles of 5 μm or less is 15%.
There is a tendency for images with less sharpness to be formed.

According to the studies conducted by the present inventors, it was found that toner particles of 5 μm or less have the main function of clearly reproducing the outline of a latent image17 and applying dense toner to the entire latent image. . In particular, in an electrostatic latent image on a photoreceptor, lines of electric force are concentrated, so the electric field strength is higher at the edge portion than inside the image, and the sharpness of the image quality is determined by the quality of toner particles collected at this portion. According to studies conducted by the present inventors, it has been found that the amount of particles of 5 μm or less is effective in solving the problem of image sharpness.

However, by reducing the particle size of the toner, the unit surface area per unit weight of the toner particles increases, so the amount of charge per toner particle increases. Therefore,
As the particle size of the magnetic toner is reduced, the amount of charge due to frictional electrification increases, and the magnetic toner gradually becomes overcharged.

Therefore, simply reducing the particle size of conventionally used magnetic toner tends to result in excessive charging, and when used in low humidity conditions, the amount of charging increases further, resulting in increased fogging, roughness, and scattering. , may cause a decrease in image density. Further, even if the toner coat is thin and uniform, and the magnetic toner has a small particle size, which is advantageous against sleeve coat unevenness, sleeve coat unevenness may occur under severe usage conditions. Further, in order to reduce the particle size, further improvement in the dispersibility of the magnetic material is required.

For this reason, there is a need for a toner that can produce good images under any environment. In other words, there is a need for a magnetic toner in which a magnetic material having desired characteristics is well dispersed in a binder resin, the amount of charge can be effectively adjusted, the reproducibility of a latent image is excellent, and an image with high resolution is produced.

[Problems to be Solved by the Invention] An object of the present invention is to provide a toner that is not affected by the environment such as temperature and humidity and provides a stable image particularly under low humidity.

Another object is to provide a toner that achieves high image quality such as high resolution.

Another object is to provide a toner that has good dispersion of magnetic material in resin, has excellent durability, and consistently produces fog-free images even after long-term continuous use. It is in.

Still another object is to provide a magnetic toner that does not impede the fixing properties and anti-offset properties of the binder resin.

[Means and effects for solving the problem] As a result of intensive research for the above purpose, the present inventor has developed a magnetic toner having a specific particle size distribution using a magnetic material with a specific compound adsorbed on the surface. It was discovered that the toner's chargeability is stabilized, the magnetic material is well dispersed in the resin, and it has excellent environmental stability and durability. The magnetic toner of the present invention is based on the findings described in Section 1. More specifically, the magnetic toner of the present invention is based on the findings described in Section 1. It is characterized by being the main component.

R1-N"-R4 e (1) Furthermore, the present invention provides a magnetic toner having at least a binder resin and a magnetic material, containing 12% or more by number of magnetic toner particles having a particle size of 5 μm or less, 8-12.7
Magnetic toner particles having a particle size of ILm are contained in an amount of 33% by number or less, and 16I1. It is characterized in that magnetic toner particles having a particle size of In or more are contained in an amount of 2.0% by volume or less, and the volume average particle size of the magnetic toner is 4 to 101.

The present invention will now be described in more detail. In the following description, "%" and "part" expressing quantitative ratios are based on weight unless otherwise specified.

In the magnetic toner of the present invention, a magnetic material on which a compound represented by the formula (1) is adsorbed is used.

These compounds consist of an alkyl group serving as a hydrophobic group and an ammonium salt serving as a parent group. Examples of the plate include the following compounds.

CH3 C1nH33-N@-C1h Br0-(3
) CH3 CH3 C+ b 833-N (Il-C old Cpo
... (4) CH3 CH3 CB, I (33 C1nH33-N""CH3 h pe ... (7) -. Generally, many compounds exhibiting wood-philicity and hydrophobicity are known, but magnetic materials When adsorbed to a surface, many of them fail to cause effective charge release and become overcharged, or moisture absorption causes excessive charge release, resulting in a significant lack of charge.

In the compound of the present invention, ammonium salt, which is a parent group, facilitates adsorption to a magnetic material. It is also believed that these functional groups suppress the polarization of the surface of the magnetic material and supplement effective charge release.

On the other hand, since the hydrophobic alkyl group of the compound of the present invention spreads over the magnetic surface -L, compatibility with the binder resin, etc. t1 is favorable.
It is believed that the dispersibility of the magnetic material in the toner is improved and significant moisture absorption is suppressed.

Magnetic toner containing a magnetic substance that has adsorbed these compounds does not absorb a lot of moisture, but under high humidity conditions, charge release increases and the magnetic toner may not be able to maintain good developability. Charging failure may occur, resulting in low image density, etc. However, by making the magnetic toner containing the magnetic material, which is a feature of the present invention, have the particle size distribution described below, the above drawbacks can be overcome and the objects of the present invention can be achieved. That is, by specifying the magnetic toner to the particle size ITJ of the present invention, it increases the charging property and also increases the friction with the frictional charging member.
This improves the charging ability of magnetic toner and makes the effect of the magnetic material used in the present invention more remarkable. Further, since reducing the particle size of the magnetic toner tends to result in excessive charging, the magnetic material of the present invention plays a role in controlling the amount of charge of the magnetic toner. In other words, the magnetic material of the present invention is suitable for use in magnetic l-ners with small particle diameters.

On the other hand, regarding the particle size, the magnetic toner of the present invention has a particle size of 5 to 1. 12% or more by number of magnetic toner particles with a particle size of m or less 1
Being - is one of the characteristics of -. Conventionally, in magnetic toners, it has been difficult to control the weight of magnetic toner particles of 51 or less, and the toner particles have tended to be overcharged. For this reason, toner particles of 5p, m or less have a strong reflection force on the developing sleeve, etc., and stick to the surface of the sleeve, inhibiting the frictional charging of other particles and generating toner particles with poor loading. It has been thought that it is necessary to proactively reduce the roughness and low density t' in some cases.

However, according to the inventors' study, 5gl11
It has been found that the following magnetic toner particles are an essential component for forming high quality images.

For example, 0.54. Using a magnetic toner with a particle size distribution ranging from +a to 30 μm, the surface potential on the photoreceptor is changed, from a large development potential contrast where many toner particles are easy to develop, to halftone, and even a small amount of toner particles. A latent image was developed by changing the contrast potential at a small development potential where only particles were developed, and the developed toner particles on the photoreceptor were collected and the toner particle size distribution was measured.
It was found that there were many magnetic toner particles of 8 HLm or less, and that there were many magnetic toner particles of 5 μm or less in bamboo. That is,
When magnetic toner particles with a particle size of 5 ILm or less, which is the most suitable for development, are smoothly supplied to develop the latent image on the photoreceptor, the latent image is faithful to the latent image, does not protrude from the latent image, and has truly excellent reproducibility. The image can be changed.

The magnetic toner containing the magnetic material of the present invention is 811. This method appropriately controls the charging of magnetic toner particles with a particle size of 5 ILm or less, particularly 5ILm or less, and effectively exhibits the effects described in the following.

Further, in the magnetic toner of the present invention, 8 to 12,7μ
One characteristic is that the number of particles in the range m is 33% or less by number. As mentioned above, this is related to the necessity of the presence of magnetic toner particles with a particle size of 5 μm or less, and magnetic toner particles with a particle size of 51 mm or less strictly cover the latent image and faithfully Although it has the ability to reproduce, in the latent image itself,
The electric field strength in the surrounding edges is higher than that in the center, so toner particles tend to adhere to the inside of the latent image more easily than at the edges, and the image density may appear thinner. especially,
Magnetic toner particles with a diameter of 5 μm or less have a strong tendency to do so.

However, the present inventors have found that this problem can be solved and further clarity can be achieved by containing toner particles in the range of 8 to 12.7 μm in an amount of 33% by number or less. In other words, it is thought that this is because toner particles with a particle size range of 8 to +2.7 p.m have a suitably controlled charge amount compared to magnetic toner particles with a particle size of 5 IJ.m or less, but the latent The toner is supplied to the inner side where the electric field strength is lower than the edge part of the image, and a uniform developed image is formed by compensating for the lack of adhesion of the inner toner particles to the edge part.
As a result, a sharp image with high density and excellent resolution and gradation is provided.

For particles with a particle size of 5 μm or less, if the number % of BO is 12 to BO, the relationship between the number % (N) and the volume % (V) is N/V = -0,04N + k (however, It is also preferable that the magnetic toner of the present invention satisfy the following relationships: , 4.5≦ and 6.5.12≦N≦SO). The magnetic toner of the present invention having a particle size distribution satisfying this range can achieve better developability.

While examining the state of the particle size distribution of 5 ILm or less, the present inventors found that there is a state of existence of fine powder that is most suitable for achieving the purpose, as shown by the above formula. That is,
For a certain N value of 12≦N≦60, a large N/V indicates that particles of 5 μm or less are widely included, and a small N/V indicates that particles around 51 are included. It is understood that this indicates that the abundance of particles is high and the number of particles with a smaller particle size is less.When N is in the range of 12 to 60, the N/V value is 2.1 to 5. 82 and further satisfies the above relational expression, good fine line reproducibility and high resolution can be achieved.

Further, it is preferable that the amount of magnetic toner particles having a particle size of 1811 m or more is 2.0% by volume or less, and is as small as possible.

The magnetic toner of the present invention solves the problems of the magnetic material used in the present invention and can withstand the recent strict demands for high image quality.

The configuration of the present invention will be explained in more detail.

It is preferable that the magnetic toner particles having a particle size of 5 μm or less account for 12% by number or more of the total number of particles, preferably 12 to 60% by number. 12 magnetic toner particles with a particle size of 5 μm or less
When the number of particles is less than %, there are few magnetic toner particles effective for high image quality, and in particular, as the toner is used by continuing copying or printing, the effective magnetic toner particle component decreases, and as shown in the present invention, the effective magnetic toner particle component decreases. The particle size distribution of the magnetic toner deteriorates, and the image quality gradually deteriorates. In addition, if it is more than 60% by number, magnetic toner particles tend to aggregate with each other, resulting in toner agglomerates larger than the original particle size, resulting in rough image quality, lowering resolution, or In some cases, the difference in density between the edges and the inside of the image becomes large, resulting in an image that appears hollow.

Further, it is preferable that the number of particles in the range of 8 to 12.7 #Lm is 33% by number or less, preferably 1 to 33% by number. If the amount is more than 33% by number, the image quality deteriorates and more development than necessary occurs, that is, too much toner is applied, leading to an increase in the toner consumption area.

On the other hand, if it is less than 1% by number, it may become difficult to obtain high image density. In addition, there is a relationship between number % (N%), 9 volume % (V%) (7) of magnetic toner particles with a particle size of 5 μm or less, and N/V=-0.04N+, and 4.5≦
indicates a positive number in the range of ≦6.5. Preferably, it is 4.5≦ and ≦6.0. As shown above, 12≦N≦80.

When k < 4.5, the number of magnetic toner particles having a particle size smaller than 5.0 ILm is small, and the image tends to be inferior in density, resolution, and sharpness. The presence of an appropriate amount of fine magnetic toner particles, which were conventionally thought to be unnecessary, contributes to achieving close packing of toner during development and forming a uniform image without roughness. In particular, by uniformly filling in thin lines and image contours, visual sharpness is further enhanced. That is, for k < 4.5,
Due to the lack of this particle size distribution component, these properties tend to be inferior.

From another perspective, production-1- also tends to require stricter conditions such as classification in order to satisfy the condition of k<4.5, which is disadvantageous in terms of yield and toner cost. Also, k
> In 6.5, due to the presence of more than necessary fine powder, the balance of the particle size distribution is lost during repeated copying, the degree of agglomeration of the toner becomes -L, and frictional charging is not performed effectively. This may result in poor cleaning or fogging.

In addition, 2 magnetic toner particles having a particle size of 16 mm LI11 or more are used.
．． It is preferably 0% by volume or less, and more preferably 1% by volume.
．． 0 volume% or less, more preferably 0.5 volume%
It is as follows. If it is more than 2.0% by volume, not only will it be a hindrance to reproducing fine lines, but also coarse toner particles of 161 or more will protrudely exist on the thin layer surface of toner particles developed on the photoreceptor during transfer. This makes the delicate state of close contact between the photoreceptor and the transfer paper via the toner layer irregular, causing fluctuations in transfer conditions and causing a defective transfer image.

In addition, the magnetic toner of the present invention cannot sufficiently retain the charge of magnetic toner particles of 18 ILm or more, resulting in charging failure and fogging in the background area and reverse area.

The volume average diameter of the magnetic toner is 4 to 10 IJ, m, preferably 4 to 9 D, rn, and this value cannot be considered in isolation from each of the components mentioned above. When the volume average particle diameter is 4 g+a or less, in applications where the image area ratio is high, such as graphic images, the amount of toner on the transfer paper is small, which tends to cause problems such as low image density. This corresponds to the edge part of the latent image mentioned earlier.
It is thought that this is due to the same reason as the reason why the internal concentration decreases. If the volume average particle diameter is 10 μm or more, the resolution is not good;
Furthermore, even if copying is good at the beginning, image quality is likely to deteriorate as the copying process continues. Furthermore, image density tends to decrease under high humidity conditions.

The magnetic toner of the present invention, which has a specific particle size distribution, can faithfully reproduce down to the fine lines of the latent image formed on the photoreceptor, and can reproduce halftone dots and digital dot I images. It provides images with excellent gradation and resolution. Furthermore, it maintains high image quality even when copying or printing is continued, and even in the case of high-density images, it is possible to perform good development with less toner consumption than conventional magnetic toner, making it economical. It also has the advantage of making the main body of a copying machine or printer more compact.

As described above, the magnetic toner of the present invention uses a magnetic material to which a specific substance is adsorbed and has a specific particle size distribution, thereby stabilizing the charging property and exhibiting excellent environmental stability and durability. I found out.

Further, since the magnetic toner of the present invention has good dispersion of the magnetic material, it has excellent durability and is also characterized by providing images with very little fog, which is preferable for reducing the toner particle size.

The amount of the compound used in (1) and (2) of the present invention depends on the binder resin, magnetic material, presence or absence of additives used as necessary, adsorption method to the magnetic material, and toner composition. It is determined by the manufacturing method and is not limited by humans. The preferred usage amount is 0.01 parts per 100 parts of magnetic material.
-5 parts (more preferably 0.1-3 parts).

If the amount used is less than 0.01 parts, the effect of charge release will not be effective, and in the case of 5 parts -1-, charge release will be excessive, resulting in poor charging under high humidity and lowering of image density. It may cause a decline.

The magnetic substance of the present invention is contained in the toner in an amount of 20 to 150 parts, preferably 40 parts, per 100 parts of the resin component.
~120 copies.

In order to achieve the same object as the present invention, although the effect is smaller than that of the present invention, it is possible to consider means of increasing the magnetic substance content. In this case, the ratio of magnetic material increases, which has a negative effect on fixing properties and causes low-temperature offset. Another disadvantage is that the organic photoreceptor is easily damaged. Furthermore, it is subject to a strong magnetic binding force from the l-toner carrier, resulting in a decrease in developability, resulting in image defects such as a decrease in image density and roughness, and deterioration in image quality.

On the other hand, in the magnetic toner of the present invention, charge is effectively released, the amount of charge is stable, and fog is always low, so it is possible to reduce the content of magnetic material. Therefore, the influence of magnetic binding force is reduced, and image quality can be improved, such as high density, no tailing, good resolution, and no roughness.

Furthermore, in addition to good dispersibility, it is advantageous in fixing properties and low-temperature offset resistance, and can fully demonstrate the performance of the binder resin. Furthermore, since it does not excessively damage the organic photosensitive layer, etc., it is preferably used in models using organic photoreceptors, etc.

The magnetic toner of the present invention exhibits its effects more effectively as the toner particle size is made smaller for the following reasons. For example, in the case of magnetic toner, reducing the particle size has drawbacks such as increased fog and image defects due to excessive charging. In order to solve these drawbacks, measures have been taken to increase the magnetic material content, but this results in the above-mentioned disadvantages.

Furthermore, the smaller the toner granulation, the greater the defects, so the magnetic substance content must be increased, and the disadvantages also become greater. However, in the magnetic toner of the present invention, it is possible to reduce the magnetic substance content, so that the adverse effects can be suppressed. The magnetic toner of the present invention has an average volume particle size of 10 ILm.
Below, the effect can be fully exhibited especially when the particle size is 9 μm or less, and it can be expected that the effect will increase as the particle size becomes smaller.

According to the findings of the present inventors, if the particle size is made smaller or the magnetic material content is reduced, the magnetic brush of the toner carrier becomes shorter and shorter (even if the toner coat layer becomes thinner). (Development capacity +1 larger) Highly accurate development is performed and latent image reproducibility is excellent, resulting in high image quality.

The magnetic toner of the present invention can achieve both of these requirements at the same time, and therefore can provide even better image quality.

The particle size distribution of toner can be measured by various methods.
In the present invention, a Coulter counter was used.

In other words, the measuring device is Coulter Counter TI.
! Using the T-11 type (manufactured by Coulter), an interface (manufactured by Nikkaki) that outputs the number distribution 9 volume distribution and 0
An X-1 personal computer (manufactured by Canon) is connected, and the electrolyte is 1% Ha (J!
Prepare an aqueous solution. As a measurement method, the electrolytic aqueous solution 10
A surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant in 0 to 1501 to 0.1 to 5 mi? In addition, 2 to 20 mg of the measurement sample is added. The electrolytic solution in which the sample was suspended was dispersed for about 1 to 3 minutes using an ultrasonic disperser, and then dispersed using the Coulter Counter TA-II, using a 100 g aperture as an aperture, and dispersing 2 to 40 particles based on the number of samples. The particle size distribution of the particles was measured and the values according to the present invention were determined therefrom.

As the binder resin used in the toner of the present invention, the following binder resins for toners can be used: a heating pressure roller having an oil coating device;

For example, monopolymers of styrene and its substituted products such as boristyrene, poly-p-chlorostyrene, and polyvinyltoluene; styrene-p-chlorostyrene copolymers, styrene-vinyltoluene copolymers, and styrene-vinylnaphthalene copolymers. , styrene acrylate copolymer,
Styrene-methacrylic acid ester copolymer, styrene-
α-Methyl chlormethacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer Styrenic copolymers such as ffi polymers, styrene-isoprene copolymers, styrene-acrylonitrile-indene copolymers; polyvinyl chloride, phenolic resins, naturally modified phenolic resins, natural resin-modified maleic resins, acrylic resins, methacrylic resins , polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumaron indene resin, petroleum resin, etc. can be used.

In the heating and pressure roller fixing method in which almost no oil is applied, there is a so-called "off-sef" phenomenon in which a part of the toner image on the toner image support member 1-5 is transferred to the roller, and a phenomenon in which the toner image on the toner image support member is transferred to the roller. The density r1 property is an important issue. Toners that require less thermal energy to fix tend to be prone to blocking or caking during storage or in a developing device, so these problems must also be addressed at the same time. The physical properties of the binder resin in the toner are most responsible for these phenomena, but according to the research of the present inventors, reducing the amount of magnetic material contained in the toner causes the toner image to become weaker on the toner image supporting member during fixing. Although the adhesion of the toner to the toner improves, the inherent properties of the binder resin tend to appear, making offset more likely to occur, and blocking or caking may also occur. Therefore, when using the heated pressure roller fixing method in which little oil is applied in the present invention, the selection of the binder resin is more important. Favorite 1
Examples of binding materials include crosslinked styrenic copolymers and crosslinked polyesters.

Como for styrene monomer of styrenic copolymer/
Examples of the mer include acrylic acid, ethyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, 2-ethyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, and ethyl methacrylate. , butyl methacrylate, octyl methacrylate, acrylonitrile, methacrinitrile, acrylamide, etc., or substituted products thereof; for example, maleic acid, butyl maleate, butyl maleate, dimethyl maleate, etc. Dicarboxylic acids having double bonds such as and substituted products thereof; Vinyl esters such as vinyl chloride, vinyl acetate, vinyl benzoate, etc.; Ethylene olefins such as ethylene, propylene, butylene, etc.; Vinyl monomers such as vinyl ketones, such as, vinyl hexyl ketone; and vinyl ethers, such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, etc., may be used alone or in combination of two or more.

Here, as the crosslinking agent, a compound having two or more polymerizable ゛, Φ: bond as )- is used, such as an aromatic divinyl compound such as divinylbenzene, divinylnaphthalene, etc.; for example, ethylene glycol diacrylate. , ethylene glycol dimethacrylate, 1.3
- Carboxylic acid esters with two ton bonds, such as butanediol dimethacrylate 1/-1; divinyl compounds, such as divinylaniline, divinyl ether, divinyl sulfide, divinyl sulfo-; and three or more Compounds having a vinyl group can be used alone or as a mixture.

In addition, when using a pressure fixing method, it is possible to use a binder resin for pressure fixing toner, such as polyethylene,
Polypropylene, polymethylene, polyurethane elastomer, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, ionomer resin, styrene-butadiene copolymer, styrene-imbrene copolymer, linear saturated polyester, paraffin, etc. There is.

The magnetic materials contained in the magnetic toner of the present invention include iron oxides such as magnetite, maghematite, and ferrite, and iron oxides including other metal oxides; metals such as Fe, Ca, and metals thereof; and A, p, Go,
Cu, Pb, Mg, Ni, Sn, Zn,
Sb, Be.

Bi, Cd, Ca, Mn, Se, Ti, W
, alloys with metals such as V, and mixtures thereof.

These ferromagnetic materials have an average particle size of about 0.1 to 2 ILm, and a magnetic property with a coercive force of 20 to 15
00e Saturation magnetization 50-200emu/g, residual magnetization 2~
20 emu/g is desirable.

Further, it is preferable to use the magnetic toner of the present invention by adding a charge control agent internally or externally to the toner.On the other hand, since the magnetic toner of the present invention stabilizes the charging, the selection range of the charge control agent is wide. It is.

Known positive charge control agents can be used in the present invention, such as nigrosine and its modified products with fatty acid metal salts, quaternary ammonium salts, diorganotin oxide, diorganotin porate, etc. alone or in combination. The above can be used in combination. Among these, nigrosine type and quaternary ammonium salts are particularly preferably used.

In addition, a monopolymer of a monomer expressed by the formula %) or a copolymer with a polymerizable monomer such as styrene, acrylic ester, or methacrylic ester as described above is used as a positive charge control agent. In this case, it also functions as (a part or all of) a binder resin.

On the other hand, known negative charge control agents can be used in the present invention, such as carboxylic acid derivatives and metal salts thereof,
Alkoxylates, organometallic complexes, chelate compounds, etc. can be used alone or in combination of two or more. Among these, acetylacetone metal complexes, salicylic acid metal complexes, and monoazo metal complexes are particularly preferably used.

Further, it is preferable to add fine silica powder to the magnetic toner of the present invention. A magnetic toner having a particle size distribution characteristic of the present invention has a larger specific surface area than conventional toners. When magnetic toner particles are brought into contact with the surface of a cylindrical conductive sleeve that has a magnetic field generating means inside for triboelectrification, the number of times the toner particle surface contacts the sleeve increases compared to conventional magnetic toner, and the toner particles Particle wear and sleeve surface contamination are more likely to occur. When the magnetic toner according to the present invention is combined with fine silica powder, wear is significantly reduced due to the presence of the fine silica powder between the toner particles and the sleeve surface. As a result, the life of the magnetic toner and the sleeve can be extended, and stable charging properties can also be maintained, making it possible to obtain a developer having a magnetic toner that is better for long-term use. Furthermore, 5I1. which plays a major role in the present invention. Magnetic toner particles having a particle size of less than ffl are due to the presence of fine silica powder,
It is more effective and can stably provide high-quality images.

As the silica fine powder, both silica fine powder produced by a dry method and a wet method can be used, but from the viewpoint of filming resistance and durability, it is preferable to use a silica fine powder produced by a dry method.

The dry method mentioned here is a method for producing fine silica powder produced by vapor phase oxidation of a silicon halide compound. For example, this method utilizes the thermal decomposition oxidation reaction of silicon tetrachloride gas in oxygen and hydrogen, and the basic reaction formula is as follows.

5i(J'++ + 2 H7+ 02→SiO2+
4 HCjl'Also, in this manufacturing process, for example, it is also possible to obtain a composite fine powder of silica and other metal oxides by using other metal halide compounds such as aluminum chloride or titanium chloride together with a silicon halide compound, These are also included.

On the other hand, various conventionally known methods can be applied to produce the silica fine powder used in the present invention by a wet method.

For example, the general reaction formula for the decomposition of sodium silicate with an acid is shown below.

Na2O・X5i07+HIJ! +H20-+5i0
2.nH2O+NaCl! Other methods include decomposition of sodium silicate with ammonia salts or alkali salts, generation of alkaline earth metal silicate from sodium silicate and then decomposition with acid to produce silicic acid, and method of decomposing sodium silicate solution with ion exchange resin. There are methods such as using silicic acid, and using natural silicic acid or silicate.

The silica fine powder mentioned here can be any of anhydrous silicon dioxide (silica) and other silicates such as aluminum silicate, sulfur/lium silicate, potassium silicate, magnesium silicate, and zinc silicate. .

Among the above silica fine powders, the specific surface area due to nitrogen adsorption measured by the BET method is 30II12/g or more (especially 50
400 m2/g) gives good results. 0.00 parts of fine silica powder per 100 parts by weight of magnetic toner.
0.01 to 8 parts by weight, preferably 0.1 to 5 parts by weight.

Further, when the magnetic toner of the present invention is positively chargeable,
Even when fine silica powder is added to prevent toner abrasion and damage to the sleeve surface, it is better to use positively charged silica fine powder than to use negatively charged silica powder, which impairs charging stability. It's just like JL-F.

As a method for obtaining a positively chargeable silica derivative, the untreated silica fine powder described above is mixed with at least one nitrogen atom in the side chain.
There is a method of treatment with a silicone oil having more than one organo group, a method of treatment with a nitrogen-containing silane coupling agent, or a method of treatment with both.

In the present invention, positively charged silica refers to silica that has a positive tripo charge relative to the iron powder carrier when measured by the pull-off method.

Used for processing fine silica powder. As the silicone oil having a nitrogen atom in its side chain, a silicone oil having at least a partial structure represented by the following formula can be used.

R,R.

-3i-0- and/or -3i-0- (wherein R1
represents hydrogen, an alkyl group, an aryl group, R represents an alkoxy group, R2 represents an alkylene group, or a phenylene group, R
(3 and R4 represent hydrogen, an alkyl group, or an aryl group, and R5 represents a nitrogen-containing heterocyclic group) The above alkyl group, aryl group, alkylene group, and phenylene group may have an organo group having a nitrogen atom. It may have a substituent such as a halogen as long as the charging property is not impaired.

Further, the nitrogen-containing silane coupling agent used in the present invention generally has a structure represented by the following formula.

Rm 5i-Yl (R represents an alkoxy group or a halogen, Y represents an amine group or an organo group having at least one nitrogen atom, m and n are integers of 1 to 3, and m + n = 4
It is. ) Examples of the organo group having at least one nitrogen atom include an amino group having an organic group as a substituent, a nitrogen-containing heterocyclic group, or a group having a nitrogen-containing heterocyclic group. Examples of the nitrogen-containing heterocyclic group include unsaturated heterocyclic groups and saturated heterocyclic groups, and known ones can be used. Examples of the unsaturated heterocyclic group include the following.

shown.

The heterocyclic group used in the present invention is preferably a five-membered ring or a six-membered ring in consideration of stability.

Examples of such treatment agents include aminopropyltrimethoxysilane, aminopropyltriethoxysilane, dimethylaminopropyltrimethoxysilane, diethylaminepropyltrimethoxysilane, dibropylaminopropyltrimethoxysilane, dibutylaminopropyltrimethoxysilane. , monobutylaminopropyltrimethoxysilane, dioctylaminopropyltrimethoxysilane, dibutylaminopropyldimethoxysilane.

Dibutylaminobrobyl monomer I xysilane, dimethylaminophenyltriethoxysilane, trimethoxysilyl-γ-propylphenylamine.

There are trimethoxysilyl-γ-propylbenzylamine, etc. Furthermore, as the nitrogen-containing heterocycle, those having the above-mentioned structure can be used. Examples of such compounds include trimethoxysilyl-γ-propylpiperidine, trimethoxysilyl- Examples include γ-propylmorpholine and trimethoxysilyl-zole.

The application amount of these treated positively charged silica fine powders is
ll: 0.00% of I7 per 100 parts by weight of charged magnetic toner.
It is effective when added in an amount of 0.1 to 8 parts by weight, and particularly preferably exhibits positive chargeability with excellent stability when added in an amount of 0.1 to 5 parts by weight. A preferred form of addition is 0.000 parts per 100 parts of positively charged magnetic toner.
It is preferable that 1 to 3 parts by weight of the treated silica fine powder be attached to the surface of the toner particles. Note that the untreated fine silica powder described above can also be used in the same amount.

Furthermore, the silica fine powder used in the present invention may be treated with a silane coupling agent, a treatment agent such as silicone oil or an organosilicon compound for the purpose of hydrophobization, or a combination of various treatment agents, if necessary. It may be treated with the above-mentioned treatment agent that reacts with or physically adsorbs the silica fine powder. Examples of such treatment agents include hexamethyldisilazane, trimethylsilane, tritylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, 7lyldimethylchlorosilane, allyl phenyldichlorosilane, and benzyldimethylchlorosilane. Silane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, i-liorganosilymerbutane, trimethylsilylmercaptanmethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane , diphenyldiethoxysilane, hexamethyldisilazane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and 2 to 12 siloxane units per minute; Dimethylborisiloxane and the like contain 17 hydroxyl groups bonded to Si in each of the units located therein.

Further, silicone oil is generally represented by the following formula.

Preferred silicone oils have a viscosity of approximately 5 to 5000 centistokes at 25°C, such as methyl silicone oil.

Preferred are dimethyl silicone oil, phenylmethyl silicone oil, chlorphenylmethyl silicone oil, alkyl-modified silicone oil, fatty acid-modified silicone oil, polyoxyalkylene-modified silicone oil, and the like. These may be used alone or in a mixture of two or more.

Further, in the present invention, it is preferable to add fine powder of a fluorine-containing polymer, such as polytetrafluoroethylene, polyvinylidene fluoride, etc., and fine powder of tetrafluoroethylene-vinylidene fluoride copolymer. In particular, polyvinylidene fluoride fine powder is preferred in terms of fluidity and polishability. The amount added to the toner is 0.01-2, O wt%, especially 0.02-1.0
wt% is preferred.

In particular, in magnetic toners that combine fine silica powder with the above-mentioned fine powders, for reasons that are not clear, the state of existence of silica attached to the toner is stabilized, and for example, the attached silica is released from the toner. The effects of inner wear and sleeve fouling are not reduced, and it is possible to further increase the acid stability.

The magnetic toner of the present invention may contain additives, if necessary. Other additives include lubricants, such as zinc stearate, or abrasives, such as cerium oxide, silicon carbide, or fluid boning agents, anti-caking agents, such as aluminum oxide.

In addition, waxy substances such as polyethylene, low molecular weight polypropylene, microcrystalline wax, carnauba wax, Zasol wax, rose fin wax, etc. are used to improve the mold release properties of hot rolls. It is also one of the preferred embodiments of the present invention to add approximately 0.5 to 5 t% of .

In the present invention, as a method for adsorbing the compound used in the present invention to the magnetic material-L, there are the following methods.

(1) A method in which each component of the toner is added during mixing and adsorbed to the surface of a magnetic material during mixing and kneading.

However, with this method, the effect may be reduced or excessive moisture absorption may occur due to penetration into the binder resin or excessive exposure of the parent wood group.

There is also a possibility that the magnetic material will not be effectively attracted to the surface of the body.

Therefore, in order to efficiently adsorb the material to the magnetic material and effectively achieve the first object of the present invention, it is preferable to adsorb the material to the magnetic material in advance, and the following methods are available.

(2) Unreleased T on magnetic material! A dry method in which the compound used in step 11 is added and then mixed and adsorbed using a Henschel mixer or a fret mill.

(3) A wet method in which the compound used in the present invention and the magnetic substance are dispersed and adsorbed in water or an organic solvent, followed by filtration and drying.

There is a dry method as a simple method, but,
In order to more uniformly adsorb the magnetic material on the surface, a wet method is excellent, and a method using water as a solvent is the most preferable method from the viewpoint of safety and ease of production 1-.

In manufacturing the toner according to the present invention, the toner constituent materials as described above are sufficiently mixed using a ball mill or other mixer, then thoroughly kneaded using a heat kneader such as a hot roll kneader or an extruder, and then cooled and solidified. Preferably, the toner is obtained by , mechanical crushing, or classification; another method is to obtain the toner by dispersing the constituent materials in a binder resin solution and then spray-drying the composition. Polymerization toner manufacturing method in which a monomer is mixed with a predetermined material to form an emulsified suspension, and then polymerized to obtain a toner; or in so-called microcapsule toner consisting of a core material and a shell material, the core material or shell material , or a method of including a predetermined material in both;
The following methods can be applied.

Further, if necessary, desired additives may be thoroughly mixed using a mixer such as a Henschel mixer to produce the magnetic l/ner according to the present invention.

The magnetic toner of the present invention can be produced by electrophotography, electrophotography, etc. by conventionally known means.
All of them can be used for developing components - for visualizing electrostatic charge images in electrostatic recording, electrostatic printing, etc.

The magnetic toner of the present invention is preferably applied to an image forming method in which a latent image is developed by flying the toner from a toner carrier such as a cylindrical sleeve to a latent image carrier such as a photoreceptor. That is, the magnetic toner is mainly charged with a tripo charge by contact with the sleeve surface, and is coated in a thin layer on the sleeve surface. The thickness of the thin layer of magnetic toner is formed to be thinner than the gap between the photoreceptor and the sleeve in the development area. When developing a latent image on the photoreceptor, it is preferable to apply an alternating electric field between the photoreceptor and the sleeve, and then cause the magnetic toner having a tripo charge to fly from the sleeve to the photoreceptor.

Examples of the alternating electric field include a pulsed electric field, an alternating current bias, or a combination of alternating current and direct current bias.

On the other hand, as a method for uniformly coating the magnetic toner on the toner carrier (sleeve), the surface is sandblasted with irregularly shaped particles to form a roughened surface with a specific unevenness. ) J-1 The surface of the carrier is uniformly uniform and constant over a long period of time.
An excellent developing device that can maintain a good toner coating state can be provided. The target surface has numerous fine incisions or protrusions arranged in random directions.

However, in a developing device that uses a 1. As a result, the density of the initial image decreases, and if the contamination progresses over time, white spots will occur in the image at intervals of the toner carrier.

This is because the components in the i-chi adhere to the slopes and four parts of the convex portions on the surface of the toner carrier, resulting in poor charging of the magnetic toner particles, and the charge ♀ of the l-s layer is low. It is something.

- Generally, the components in a magnetic toner consist of materials such as a magnetic binder resin, a charge control agent, and a release agent. It will be done, but
Currently, the selection of materials is restricted.

Furthermore, if the surface of the toner carrier is smooth or has a specific unevenness formed by a plurality of spherical trace depressions, no matter what kind of material the magnetic l-toner is applied to, the surface This makes it difficult for toner components to adhere to the surface of the toner, making it possible to prevent or reduce contamination over a long period of time.

However, in order to achieve the ability to uniformly coat a toner carrier with magnetic toner, it is difficult to obtain a toner carrier having a surface with specific irregularities formed by spherical trace depressions. Under certain circumstances, this toner carrier is inferior to a toner carrier having an uneven surface with countless incisions or protrusions in random directions, but is superior to a toner carrier having a completely smooth surface.

- On the other hand, by using the magnetic toner of the present invention in a toner carrier having a surface with spherical trace depressions, it is possible to prevent the toner coating layer from becoming excessively thick, and to achieve a smooth surface without causing toner coating unevenness. Even on a toner carrier having the following properties, it is possible to coat the toner uniformly over a long period of time. As a result, it is possible to obtain clear, high-quality images with high image density, excellent fine line reproducibility and gradation, and no fog over a long period of time.

The present invention will be described in detail below, and the toner carrier will hereinafter be referred to as a sleeve.

When the sleeve of the present invention has a surface with an uneven surface formed by a plurality of spherical trace depressions, a blasting method using regular particles can be used to obtain the surface condition. As the regular particles, for example, various rigid spheres such as metals such as stainless steel, aluminum, steel, nickel, and brass, ceramics, plastics, and glass beads having a specific particle size can be used. By blasting the sleeve surface using regular particles having a specific particle size, it is possible to form a plurality of spherical trace depressions with approximately the same diameter R.

In the present invention, the diameter R of the plurality of spherical trace depressions on the sleeve surface is preferably 20 to 250 μm, and the diameter R is 20 μm.
If it is less than Lm, contamination due to components in the magnetic toner increases, which is not preferable. Therefore, it is preferable that the regular particles used during the blasting treatment of the sleeve surface have a diameter of 20 to 250 μm. In addition, in the present invention, the pitch P of the unevenness on the sleeve surface and the surface roughness d are determined by measuring the surface of the sleeve using a microsurface roughness meter (manufactured by Tiller-Hopson, Koita Institute, etc.). The roughness d is based on JIS 10-point average roughness (RZ) 111S B 0801J. Also, the pitch P is 0.1 for the convex part or the four parts on both sides.
It is calculated as follows from the number of peaks within a standard length of 0.25 mm, counting the height of μ or more as one peak.

250 (L) / Number of peaks included in 250 (L) In the present invention, the pitch P of the unevenness on the sleeve surface is 2 to 250 (L).
100 pL is preferable, and if P is less than 2 meL, contamination of the sleeve by components in the magnetic toner increases, which is not preferable. In addition, the surface roughness d of the unevenness on the sleeve surface is 0,1
~5 μm is preferable, and if d is 5 μm or more, unevenness may occur in a method in which development is performed by applying an alternating voltage between the sleeve and the latent image holder to cause magnetic toner to fly from the sleeve side to the latent image surface. This is not preferable because the electric field tends to concentrate in some areas and cause image disturbance.

In the present invention, fine line reproducibility was measured by the following method. That is, exactly the width 1001LI1
An image of an original manuscript with thin lines marked as 1 was copied under the appropriate copying conditions as a sample for measurement, and a Luzex 450 particle analyzer was used as a measuring device.
The line width is measured using an indicator from the enlarged monitor image. At this time, since the line width measurement position has irregularities in the width direction of the fine line image of the toner, the average line width of the irregularities is taken as the measurement point. From this, the value of fine line reproducibility (%
) is calculated by the following formula.

In the present invention, resolution was measured by the following method. In other words, it is a pattern consisting of five thin lines with equal line width and spacing, and 2.8.3.2.3.8 in 1 mm.
．． 4. Create an original image that appears to have 1 or 8.0 lines. The images copied from the original document with these 10 types of line images under appropriate copying conditions were observed with a magnifying glass, and the number of images with clearly separated thin lines (wood/II
1m) is taken as the value of resolution.

The larger this number, the higher the resolution.

[Examples] The present invention will now be explained in more detail with reference to Examples, which are not intended to limit the present invention in any way. All parts in the following formulations are parts by weight. Examples of manufacturing the magnetic material used in the present invention are shown below.

Production Example 1 Magnetic substance A (magnetic iron oxide) was added to an aqueous solution 11 containing 1.0 g/i of compound (4) so that the slurry concentration was 93.5 g/II', and after stirring for 1 hour, bj and 120°
Magnetic material B was obtained by heating and drying at C.

At this time, the amount of compound (4) adsorbed was 0.8 parts per 100 parts of the magnetic material.

Production Example 2 1.0 g/i of compound (10) instead of compound (4)
Magnetic material C was obtained in the same manner as in Production Example 1 except that the aqueous solution of ' was used.

The adsorption amount of the compound (lO) is 0.00 parts per 100 parts of the magnetic material.
There were 8 parts.

Production Example 3 1.5g/ of compound (14) instead of compound (10)
A magnetic material was obtained in the same manner as in Production Example 1, except that the aqueous solution of j) was used.

The amount of compound (14) adsorbed is 1.0 parts per 100 parts of the magnetic material.
It was part 1.

Production Example 4 Magnetic material F was obtained in the same manner as in Production Example 1, except that magnetic material E (magnetic iron oxide) was used instead of magnetic material A.

The adsorption amount of compound (4) is 0.8 per 100 parts of magnetic material.
It was a department.

Since the compound of the present invention is distributed into the solvent at a constant concentration, the amount of adsorption is determined by the concentration of the original solution of the compound and the concentration of the slurry of the magnetic material.

In addition, when applying 10 KOe of magnetic material A, the magnetic property is a coercive force of 13
30 e, saturation magnetization of 83.7 parts mu/g, and residual magnetization of 12.5 parts mu/g. The average particle size is 0.15Ii,
It is m.

Magnetic material E has a coercive force of 830e and a saturation magnetization of 91.8, respectively.
part mu/g, and residual magnetization 6.4 parts mu/g. The average particle size is 0.20 μm.

Example 1 Magnetic material B (Compound (4) adsorption amount 1.0%) 80 parts Paper molecular weight Ethylene-propylene copolymer 4 parts Nigrosine dye 2 parts The following materials were premixed in a Henschel mixer and heated to 150°C. Knead with a heated extruder, cool and coarsely grind with a cutter mill.
The mixture was pulverized using a pulverizer using a jet stream, and further classified using an air classifier to obtain a classified product having an average volume particle size of 8.2. The particle size distribution is shown in Table 1. 100 parts of this classified material was mixed with positively charged hydrophobic colloidal silica (BET).
200m2/g) and 0.8 part of the magnetic toner were thoroughly mixed in a Henschel mixer to obtain a magnetic toner. The obtained magnetic I・
A commercially available electrophotographic copying machine (product name NP-1215° manufactured by Canon, roughened developing sleeve, recess diameter 53 to 62 mm)
500 with a roughness pitch of 30 μm and a surface roughness of 2k).
0 copies1. The results are shown in Table 2.

As shown in Table 2, high quality images with no fog were obtained. Also 15℃, 10%RH132.5℃, 85%RH
Similar good results were obtained with the

The charge r- of the toner in the toner carrier during the test was +
It was stable within the range of 6 to -10 nc/cm2.

In the present invention, the charge amount of the 1-layer per unit area of the 11-supporting member 1- was determined using the so-called attraction Faraday cage method. In this suction type Faraday cage method, the outer cylinder is pressed against the toner carrier to suck all the toner in a constant area of −1− on the carrier, and the toner is collected in a filter in the inner cylinder. From this, the weight of the toner layer per unit area of the toner carrier-L can be calculated. At the same time, by measuring the amount of charge accumulated in the inner cylinder which is electrostatically shielded from the outside, it is possible to determine the amount of charge per unit area of the toner carrier.

Example 2 80 parts of magnetic substance C was used instead of magnetic substance B used in Example 1, and hydrophobic colloidal silica (BET 300 m2/g) was used.
A toner was obtained in the same manner as in Example 1 except that 0.45 parts of the toner was used.

The particle size distribution of the classified powder is shown in Table 1.

Table 2 shows the results of a copying test similar to that in Example 1. As shown in Table 2, high quality images faithful to the original were obtained. Further 15°C910%RH232,5°C
Similarly good results were obtained at 185% RH.

The amount of charge of the toner on the toner carrier l- during the test was +7
It was stable within the range of ~+10 nc/cm2.

Example 3 Instead of the magnetic material B used in Example 1, 90 parts of 1F electrostatic hydrophobic silica (BET 200m?/1F) was used.
A toner was obtained in the same manner as in Example 1 except that g) was changed to 0.7 parts.

The particle size distribution of the classified powder is shown in Table 1.

Table 2 shows the results of the copying test conducted in the same manner as in Example 1. As is clear from Table 2, images with excellent resolution were obtained. Also 15°C, 10%RH132, 5°C98
Similar good results were obtained at 5% RH'l'.

The amount of charge of I-toner on the toner carrier F during the test was +
It was 6 to -10 nc/c112.

Example 4 Crosslinked polyester resin (%w=300,000) 100 parts Magnetic material F 70 parts Paper molecular weight Ethylene-propylene copolymer 3 parts 3.5-di-t-butylsalicylic acid chromium complex 2 parts A classified powder was obtained in the same manner as in Example 1, and 0.6 part of hydrophobic colloidal silica (BET 300 m2/g) was added externally.

The particle size IIj of the classified powder is shown in Table 1.

This toner is applied to a commercially available electrophotographic copying machine (product name NP-75).
Table 2 shows the results of a 5,000-sheet copying test using No. 50, manufactured by Canon (the roughness of the developing sleeve was an irregular sandblasting process). As is clear from Table 2, images with excellent image quality and toner consumption were obtained.

Also, 15°C110%R1 (,32,5°C, 85%RH
Similar results were obtained below. The amount of charge of the toner on the toner carrier during the test was -6 to -9 nc/cn+2.

Comparative Example 1 A toner was obtained in the same manner as in Example 1, except that 80 parts of magnetic material A was used instead of magnetic material B used in Example 1.

Table 1 shows the particle size distribution of the classified powder, and Table 2 shows the results of a copying test conducted in the same manner as in Example 1. As is clear from Table 2, good results were obtained. However, 15°
C2 Under 10%RH, a good image was obtained at the beginning, but as the number of copies was increased, the image became slightly rough and foggy, and the density decreased (1.35 → 1.15).
6. At this time, the toner band TK-C of the toner carrier T was -16 nC/Cl112.

In Comparative Example 2, 100% of the magnetic material A was used instead of the magnetic material B used on the male side 1.
I.na was obtained in the same manner except that 1 part was used.

The particle size distribution of the classified product is shown in Table 1, and the results of a copying test conducted in the same manner as in Example 1 are shown in Table 2. As shown in Table 2, good results were observed, but trailing and roughness were slightly more common than in Example 1. Although there were no problems with Practical I-8, the fixing performance was somewhat poor, and there were many scratches on the photosensitive drum, which began to appear on the images after 5,000 copies were printed.

Comparative Example 3 A toner was obtained in the same manner as in Example 1, except that 50 parts of magnetic material B was used.

The particle size distribution of the classified product is shown in Table 1, and the results of a copying test conducted in the same manner as in Example 1 are shown in Table 2.

There were no problems with image density or fog, but image quality such as resolution and fine line reproducibility was poor.

Also, the image density is low at 32.5°C and 285%RH.
It is especially low at the beginning (1.12-1.21) and solid black is 1. It was as low as lO.

The initial charge amount of the toner on the toner carrier is +4.
It was 5 nc/cm2.

Comparative Example 4 A toner was obtained in the same manner as in Example 1, except that 60 parts of magnetic substance A was used instead of magnetic substance B.

The particle size distribution of the classified product is shown in Table 1, and the results of a copying test conducted in the same manner as in Example 1 are shown in Table 2.

There was no problem with image density, but there was a lot of fogging, solid black areas were rough, and image quality such as resolution and fine line reproducibility was poor.
Toner consumption was also high. In addition, sleeve coat unevenness was observed in the non-image area.

(The following is a blank space) [Effects of the Invention] The present invention is a magnetic toner that has been subjected to the above magnetic surface treatment and has a specific particle size distribution, and therefore exhibits the following excellent effects. .

(1) Maintains stable charging even in low humidity environments.

(2) Provides images that are stable and have excellent fine line reproducibility and resolution without being affected by temperature or humidity.

(3) It has excellent durability and maintains its initial high image quality even after long-term use.

(4) Provide high image density with low consumption.

(5) The magnetic material is well dispersed in the binder resin, has excellent durability, and consistently provides fog-free images.

(6) The performance of the binder resin is fully demonstrated without adversely affecting fixing properties and anti-offset properties.

Claims (4)

[Claims] (1) Magnetic toner particles having a particle size of 5 μm or less, the magnetic toner having at least a magnetic material adsorbing a binder resin, a compound represented by the following general formula (1) or (2), and a mixture thereof. Contains 12% or more by number, 8
Magnetic toner particles having a particle size of ~12.7 μm are contained at 33% or less by number, magnetic toner particles having a particle size of 16 μm or more are contained at 2% by volume or less, and the volume average particle size of the magnetic toner is 4~12.7 μm. A magnetic toner characterized by having a diameter of 10 μm. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(1) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(2) [In the above general formula, R^1 is a carbon number of 6 to 24 Alkyl group, alkenyl group R^2 is an alkyl group having 1 to 24 carbon atoms, alkenyl group R^3 is an alkyl group having 1 to 8 carbon atoms R^4 is an aralkyl group, alkyl group having 1 to 8 carbon atoms The group X represents a halide ion. ] (2) An electrostatic image carrier that holds an electrostatic image on its surface and a toner carrier that carries the magnetic toner on its surface according to claim (1) are arranged with a certain gap in the developing section, and the magnetic toner is A developing method characterized in that the toner is regulated to a thickness thinner than the gap on a toner carrier and transported to a developing section, and the toner is developed in the developing section while applying an alternating electric field to the toner. (3) The developing method according to claim (2), wherein the toner carrier has a surface that is smooth or has an uneven surface formed by a plurality of spherical trace depressions by blasting with regular particles. (4) The surface of the toner carrier has a spherical trace depression with a diameter R=
20 to 250 μm, uneven pitch P = 2 to 100 μm,
4. The developing method according to claim 3, wherein the surface roughness d is 0.1 to 5 μm.