JPH05333590A - Developing agent for developing electrostatic charge image - Google Patents

Abstract

PURPOSE:To provide a developer for developing an electrostatic charge image excellent in developing property, particularly effect to suppress selective developing and suitable for an image forming method using an organic photosensitive body. CONSTITUTION:An insulated magnetic toner having 4-12mum weight average particle diameter (t-D4), 1-10mum number average particle diameter (t-D1) and 1.01-2 ratio of (t-D4)/(t-D1), a fluidizing agent and a metal oxide powder having 0.6-5mum weight average particle diameter (m-D4), 0.5-4mum number average particle diameter (m-D1), 1.0-2.4 ratio of (m-D4)/(m-D1) and the same or larger ratio of (m-D4)/(m-D1) as or than that of (t-D4)/(t-D1) are contained and the blended quantity of the metal oxide powder is 2 to 8 times that of the fluidizing agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic charge image developing developer used in image forming methods such as electrophotography, electrostatic recording and electrostatic printing.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic method, US Pat. No. 2,297,691 and JP-B-42-23910 are known.
Many methods are known as described in Japanese Patent Publication No. 43-24748 and Japanese Patent Publication No. 43-24748. Generally, a photoconductive substance is used to form an electric latent image on a photoconductor by various means, and then the latent image is developed with a toner, and a toner image is formed on a transfer material such as paper if necessary. After transfer, the toner is fixed by heating, pressure, heating and pressurizing or solvent vapor to obtain a toner image.

Various methods and devices have been developed for the final step of fixing the toner image on a sheet such as paper, but the most general method at present is a pressure heating method using a heating roller.

The pressure contact heating method using a heating roller fixes the toner image by allowing the surface of the heat roller having releasability to the toner and the toner image surface of the fixing sheet to come in contact with each other under pressure while passing through the fixing sheet. To do. In this method, the surface of the heat roller and the toner image on the sheet to be fixed come into contact with each other under pressure, so that the thermal efficiency at the time of fusing the toner image on the sheet to be fixed is extremely good, and quick fixing is required. And is very effective in high speed electrophotographic copying machines.

In such a fixing method, the use of a binder resin containing an acid component in order to improve the fixing property has been proposed in JP-A-55-134861. However, a toner using such a binder resin is apt to cause insufficient charging under high humidity and excessive charging under low humidity, and is easily affected by environmental changes. Further, fogging is likely to occur and the image density may be low.

On the other hand, the acid anhydride has a function of improving the charging property, and examples of applying a resin containing the acid anhydride are disclosed in JP-A-59-139053 and JP-A-62-280758.
It is proposed in Japanese Patent Publication No. In these methods, a polymer having a high density of acid anhydride units is diluted with a binder resin. In these methods, it is necessary to uniformly disperse the acid anhydride-containing resin in the binder resin, and if not well dispersed, the toner particles become non-uniformly charged, fogging easily occurs, and the developability is adversely affected. ..

Therefore, by dispersing and diluting the acid anhydride units in the polymer chain in the binder resin by copolymerization, the problem of dispersion can be solved and the toner particles can be obtained with uniform chargeability. .. Japanese Patent Laid-Open No. 61-123856,
These toners have been proposed in Japanese Patent Laid-Open No. 61-123857. These toners have good fixability, offset resistance, and developability.

However, when such a toner is applied to a high-speed copying machine under low humidity, it may become overcharged, resulting in fogging or a decrease in density.

Further, in recent years, there has been a demand for multifunctional copying machines and higher image quality of copied images by digitizing copying machines and making toner particles smaller.

However, in the multi-functionalization of the copying machine, for example, a part of the image is erased by exposing,
Next, in the function of performing multiple multicolor copying in which another image is inserted in that portion, or in the function of removing the frame around the copy paper, a fog occurs in a portion of the image to be whitened.

That is, if an image is erased by applying a potential opposite to the latent image potential with respect to the development reference potential with strong light such as an LED or a fuse lamp, there is a problem that the fog tends to occur at that portion. ..

Further, although the resolution and the sharpness of the image can be improved by the digitization and the reduction of the toner particle size, various problems occur.

First, there is the above-mentioned problem of fog. By reducing the toner particle size, the surface area of the toner is increased, so that the width of the charge amount distribution is increased and fogging is likely to occur. In addition, the increase in the toner surface area makes the charging characteristics of the toner more susceptible to the environment.

Further, when the toner particle size is reduced, it is obvious that the dispersion state of the polar substance and the colorant has a great influence on the charging property of the toner.

Further, in recent digital copying machines,
In a photographic image containing characters, the characters of the copied image are clear, and the photographic image is required to have density gradation that is faithful to the original. Generally, in copying a photographic image containing characters, if the line density is increased to make the characters clear, not only the density gradation of the photographic image is impaired, but also the halftone image becomes very rough. On the other hand, if an attempt is made to improve the density gradation of the photographic image, the density of the character line will decrease and the sharpness will deteriorate.

In recent years, the image density has been read and the density gradation has been improved to some extent by digital conversion. However, the present situation is still not enough.

This is largely due to the developing characteristics of the developer. That is, the developing potential (difference between the photosensitive member potential and the developer carrying member potential) and the image density do not have a linear relationship.
As shown by (solid line), a downward convex curve is drawn where the development potential is low and an upward convex curve is drawn where the development potential is high. Therefore, in the halftone region, a slight change in the development potential causes a very large change in the image density. As a result, it is difficult to obtain a sufficiently satisfactory density gradation.

Usually, in order to copy a line image and maintain its sharpness, the maximum image density in the solid image portion which is not easily affected by the edge effect is 1.30 because it is affected by the edge effect.
Something is enough.

However, in a photographic image, the maximum density of the photograph itself is largely due to its surface glossiness, and is 1.9.
It is very high, from 0 to 2.00. Therefore, in copying a photographic image, even if the glossiness of the surface is suppressed, since the image area is large, the density is not increased by the edge effect. Therefore, the maximum image density in the solid image part is 1.4 to About 1.5 is necessary.

Therefore, the developing potential and the image density are in a linear (linear) relationship, and the maximum image density is 1.4 to
Setting 1.5 is very important for copying a photo image with text.

For this purpose, it is important to control the charge amount of the toner as uniformly as possible.

As a method for stabilizing the charge amount by preventing an increase in the charge amount of the toner by using a conductive powder, Japanese Patent Laid-Open No. Sho 58-58 is known.
-66951, JP-A-59-168458-16
A method using conductive zinc oxide and tin oxide is disclosed in Japanese Patent No. 8460 and Japanese Patent Laid-Open No. 59-170847. According to these methods, the maximum image density is 1.3.
In a system using a large amount of conductive powder, the value is 1.4 or more, but the density gradation is poor. It is well known that the charge amount distribution also exists in the charge amount of the toner, and the larger the charge amount of the toner, the wider the distribution width. That is, these methods are intended to reduce the charge amount and sharpen the charge amount distribution by attaching the conductive powder to the toner having a high charge amount. However, even with these methods, a sufficiently satisfactory image cannot be obtained in copying a photographic image with text.

Further, a non-magnetic toner having a volume average particle diameter of 5 to 20 μm is mixed with a fine powder having a volume average particle diameter of 1/20 to 1/2 to stabilize the toner replenishment property to form a thin layer. JP-A-61-183664 discloses a method in which a uniform toner layer is formed by the above method to obtain a sufficient triboelectric charge amount.
In this method, in the color toner, it is possible to stabilize the toner replenishment and form a thin layer on the developer bearing member to increase the charge amount, but in the magnetic toner, as described above,
The charge amount distribution is sharpened, and when the copy is made, the maximum density of 1.4 to 1.5 and sufficient density gradation cannot be obtained.

Further, Japanese Patent Laid-Open No. 60-32060 discloses a method of using two kinds of inorganic powders to remove paper powders, ozone adducts, etc. generated or adhered to the surface of the photoconductor. ..

Further, in Japanese Patent Application Laid-Open No. 2-110475, two kinds of inorganic fine powders are used for a toner using a metal-crosslinked styrene acrylic resin, and paper powder or ozone generated or attached to the surface of a photoreceptor is used. A method is disclosed which removes additives and the like, fixes toner, improves toner scattering under high temperature and high humidity, image deletion, and image density reduction.

Although it is possible to remove the adhering substance on the photoreceptor by these methods, the above-mentioned various problems have not been solved yet.

Further, Japanese Patent Laid-Open No. 61-236559,
Japanese Patent Laid-Open No. 63-2073 discloses a method of improving the chargeability of toner by using cerium oxide particles to dissociate aggregated silica and toner lumps. In this method, the chargeability is certainly improved, but when an organic photoconductor is used, the effect of the cerium oxide as a polishing agent is great, so when the copying is continued, the resin on the photoconductor surface layer is gradually scraped off, As a result, the performance of the photoconductor deteriorates, and the quality of the copied image gradually deteriorates.

At present, there is no developer that solves all of the above various problems.

[0029]

SUMMARY OF THE INVENTION An object of the present invention is to provide a developer for developing an electrostatic charge image used in an image forming method using an organic photoconductor, which solves the above problems.

An object of the present invention is to provide a developer for developing an electrostatic charge image capable of obtaining a high-density copy image without impairing the fixability, without fog.

An object of the present invention is to provide a developer for developing an electrostatic charge image which gives a good image under low and high humidity without being influenced by environmental changes.

An object of the present invention is to provide a developer for developing an electrostatic charge image which gives a stable and good image even in a high speed machine and has a wide range of applicable models.

An object of the present invention is to provide a developer for developing an electrostatic charge image which is excellent in durability, has a high image density even after continuous use for a long time, and is free from fog on a white background to obtain a copy image. is there.

The object of the present invention is excellent in resolving power and reproducibility of fine lines, and in the case of a photographic image containing characters, the characters of the copied image are clear and the photographic image has a density gradation that is faithful to the original. It is to provide a developer for developing a charge image.

The object of the present invention is to achieve a uniform coating of the magnetic toner on the developer carrier and a stable charging of the magnetic toner on the developer carrier uniformly for a long time, An object of the present invention is to provide a developer for electrostatic charge image development that makes the flight of magnetic toner more efficient.

[0036]

According to the present invention, the weight average particle diameter (t-D ₄ ) is ₄ to 12 µm, and the number average particle diameter (t-D ₁ ) is ₁ to 10 µm. t-D ₄ )
/ Insulating magnetic toner (t-D ₁₎ the ratio of is 1.01 to 2, fluidizing agents, and the weight average particle diameter (m-D ₄₎ is 0.6～5Myuemu, number average particle The diameter (m-D ₁ ) is 0.5 to ₄ μm, the ratio of (m-D ₄ ) / (m-D ₁ ) is 1.1 to 2.4, and (m-D ₄ ) / ( m-D
The ratio of ₁₎ contain the same or greater metal oxide powder than the ratio of the _{(t-D 4) / (} t-D 1), the amount of the metal oxide powder, the fluidized agent The developer for developing an electrostatic charge image is characterized in that the amount is 2 to 8 times the compounding amount.

As described above, it is well known that the charge amount distribution also exists in the toner charge amount. In the case of a one-component magnetic toner, this distribution state is affected by the distribution state of materials constituting the toner, such as a magnetic material and a coloring agent, and the particle size distribution of the toner. When the materials forming the toner are uniformly dispersed, the charge amount distribution is mainly affected by the particle size distribution of the toner. Generally, a toner having a small particle size has a large charge amount, and a toner having a large particle size has a small charge amount. Further, the distribution width of the toner having a larger charge amount is wider and the toner having a smaller charge amount is narrower.

As a method of using a toner having a high charge amount to sharpen the charge amount distribution, there is a method of lowering the charge amount by attaching conductive powder to the toner as described above. Good performance, but the concentration is not sufficient at the maximum concentration. The present inventors considered the reason for this as follows.

In the method of reducing the amount of electrification by adhering the conductive powder to the toner, the conductive powder itself is slightly charged but does not uniformly adhere to the toner, and electrostatic charge is applied to the toner having a small particle size. It is thought that more will be attached due to the physical force.

In charging due to friction between toner particles, the surfaces of the toner particles that are in contact with each other are charged, and therefore, even on the same toner surface, positive and negative charged charges are distributed. Therefore, since the toner having a smaller particle size has a larger surface area, it is considered that the toner easily adheres regardless of the charge polarity of the conductive powder. Further, since the toner having a smaller particle size has a larger surface area and the amount of charge per unit weight is larger, when the toner is charged to the opposite polarity, it appears as a fog on a white background when copying. Therefore, the fog is improved by putting the conductive powder into the toner and adhering it to the reverse polarity toner having a small particle size.

However, the toner having a small particle size, to which the conductive powder having a large effect of reducing the charge amount is attached, is selectively developed because the charge amount is lowered. Therefore, although the density gradation is improved, since the toner having a small particle size is melted and spread by fixing, the area covering the fixing support is smaller than that of the toner having a large particle size. However, it is slightly inferior to that of a toner having a large particle size.

Further, since only the toner having a small particle size is selectively developed, the halftone roughness is good at the initial stage, but when copying is continued, the toner particle size in the developing device becomes large and deteriorates.

As a result of earnest studies, the inventors of the present invention reduced the charge amount of the toner, and on the contrary to the reduction of the charge amount of the toner, the charge amount of the toner having a low charge amount in the charge amount distribution due to the contact between the toner and the metal oxide. I found a way to raise it. That is, instead of adhering the metal oxide to the toner for development, the toner and the metal oxide are contact frictionally charged in the developing device to obtain a uniformly charged toner.

For a toner of a certain particle size, a very small metal oxide powder has a very large image force on the toner itself, so that stirring and rotation of the developer carrying member in the developing device are caused. Even if it receives the shearing force due to the toner, it remains attached to the toner, and thus has the effect of reducing the charge amount of the toner as described above. However, when a metal oxide powder having a certain size with respect to a toner having a certain particle diameter adheres to the toner and is separated due to the shearing force received in the developing device, the number of times of contact with the toner increases, so On the contrary, the charge amount of the toner increases.

The present inventors have made detailed studies based on this idea and have found out the following.

Width of particle size distribution of metal oxide powder [(m-D
₄ ) / (m-D ₁ )] is the width of the toner particle size distribution [t-D
₄ ) / (t-D ₁ )] or a wider one, a uniform charging property can be obtained. This is because, for a toner having a certain particle diameter, a metal oxide having a particle diameter within a certain range has the ability to remarkably increase the charge amount of the toner. Therefore, the width of the particle size distribution of the metal oxide powder is preferably wider than the width of the particle size distribution of the toner.

Further, it has been understood that it is important that the developer satisfies the following constituent requirements.

The weight average diameter of the toner is 4 to 12 μm, the number average diameter is 1 to 10 μm, and the distribution width [(t-D ₄ ) / (t-D ₁ )] is 1.01 to 2. To be.

Using a superplasticizer.

The weight average particle diameter of the metal oxide powder is 0.6.
A 5 .mu.m, a number average particle diameter of 0.5 to 4 .mu.m, its distribution width _{[(m-D 4) /} (m-D 1)] 1.
Must be 1 to 2.3.

These are due to the following reasons.

When the weight average particle diameter of the toner exceeds 12 μm, the halftone image becomes rough and the toner becomes 4
If it is less than μm, the fog on the white background becomes poor.

When the toner particle size exceeds 12 μm, a metal oxide powder having a large particle size is required to increase the charge amount of the toner. The metal oxide powder having a large particle size is not developed and is accumulated in the vicinity of the developer carrier. Therefore, a large amount of metal oxide powder having a large particle size is present on the developer carrying member, and the amount of toner to be developed is small,
White streaks appear on the image, the image density decreases, and the halftone image becomes less rugged.

When the toner particle size is less than 4 μm, in order to increase the charge amount of the toner, the relationship between the particle sizes is as follows.
The particle size of the metal oxide powder may be reduced. However, at such a particle size, the surface area of the toner increases, so that the chargeability of the toner cannot be kept uniform unless a large amount of metal oxide powder is used. If a large amount of metal oxide powder with a small particle size is used, the cleaning blade slips through, that is, cleaning failure occurs, or the metal oxide powder gradually scrapes off the resin layer of the organic photoconductor. In addition, the sensitivity of the photoconductor is deteriorated, and the copy image is deteriorated due to a decrease in image density.

Width of toner particle size distribution [(t-D ₄ ) /
When (t−D ₁ )] is larger than 2, as described above, the spread of the charge amount distribution due to the particle size distribution becomes large, so that even if the metal oxide powder according to the present invention is used, sufficient uniform chargeability cannot be obtained. I can't get it.

Further, in the absence of the fluidizing agent, the fluidity of the one-component magnetic toner used in the present invention is remarkably lowered, which also causes charging failure. Further, when there is no fluidizing agent, the fluidity of the waste developer in the cleaning section is remarkably reduced, so that the amount of abrasion of the resin on the photoreceptor surface layer increases,
Image damage is caused by scratching.

When the metal oxide powder having a weight average particle size of more than 5 μm is used, although the chargeability of the toner is improved to some extent, the metal oxide powder is not developed in the white background reversal part and is consumed because it is large. Because it is not done, in the developing device,
As a result, the amount of metal oxide powder on the developer carrier increases, and the quality of the copied image gradually deteriorates. If the weight average particle diameter is smaller than 0.6 μm, the charging property of the toner is lowered as described above, which is not suitable for the purpose of the present invention. Further, the ratio of _{(m-D 4) / (} m-D 1) is larger than 2.4, the particle size distribution is too wide, that too fine particle size and, most things too coarse particle size It will be included, which is not preferable.

Further, in the toner and the metal oxide powder according to the present invention, it is preferable that the metal oxide powder is hardly charged or that the polarity is opposite to that of the toner. In the present invention, the purpose is to increase the charge by frictional charging, rather than using metal powder by adhering it to the toner.
If the same polarity is used, not only will the toner charge amount be reduced, but also the triboelectric charging speed will be reduced, the initial copy density will be low, and the density will gradually increase as copying is continued. A rising phenomenon appears.

Further, when a metal oxide powder having a polarity opposite to that of the toner is used, the toner having a small particle size and the metal oxide powder having a small particle size interact with each other when mixed. That is, those having a large amount of charge per unit weight and a large working surface area act on each other due to their opposite polarities. Therefore, the toner having a large particle diameter and the metal oxide powder having a large particle diameter interact with each other. In the same developing device, a combination of a toner having a small particle diameter and a metal oxide powder is less affected by frictional electrification by stirring than a combination of large particles. This is because, when the shearing force due to stirring is applied, the small things often slip through without receiving the shearing force. Further, the amount of electric charge that the metal oxide powder having a small particle diameter gives to the toner having a small particle diameter is small because the total charging amount of the metal oxide powder is small. On the contrary, in the case of the combination of the metal oxide powder having a large particle diameter and the toner having a large particle diameter, the charge amount was low depending on the particle diameter because the total charge amount of the metal oxide powder was large due to the influence of contact charging due to stirring. The charge amount of toner with a large particle size increases,
In terms of developing ability, there is no difference in toner particle size, that is, the phenomenon of selective development described above does not occur.

From the above, the particle size of the toner and the particle size of the metal oxide powder are important, but considering the charging mechanism by the interaction, the particle size distribution width of the toner and the particle size of the metal oxide powder are considered. The relationship between the distribution width and the relationship between the toner particle size and the metal oxide powder particle size are very important.

As a result of detailed examination, it is preferable that the toner and the metal oxide powder satisfy the relationship of the following expression with respect to the above-mentioned things, because they can be more effectively exhibited.

[0062]

[Formula 1]

[0063]

[Formula 2] The above-mentioned various problems can be solved only when the developer satisfies the above constituent requirements. Further, in the developer of the present invention, it is possible to prevent the phenomenon that only the toner having a small particle diameter described above is selectively developed and consumed, and therefore, even if copying is continued, halftone It is possible to obtain an image which is free of roughness, has excellent reproducibility of fine lines, and is sufficiently satisfactory in terms of density gradation and maximum image density.

Further, it is important that the compounding amount of the metal oxide powder is 2 to 8 times the compounding amount of the fluidizing agent in order to maintain good developing characteristics of the developer and suppress selective development. is there. Further, the constitution of the developer preferable for achieving the object in the invention will be described in detail below.

Examples of the binder resin used in the present invention include vinyl resins, polyester resins and epoxy resins. Among them, vinyl resins and polyester resins are more preferable in terms of charging characteristics and fixability.

As a more preferable embodiment of the vinyl resin, in order to further improve not only the fixability but also the chargeability of the toner, an acid anhydride group is contained and the total acid value of the vinyl resin is increased. (A) is 2 to 100 mgKOH / g, preferably 5 to 70 mgKOH / g, more preferably 5 to
It is preferable to use the one having 50 mgKOH / g.

When the total acid value (A) is less than 2 mgKOH / g, it is difficult to obtain a good fixability, and when it exceeds 100 mgKOH / g, it becomes difficult to control the chargeability of the toner.

The component that gives an acid value includes a carboxyl group and an acid anhydride group, and these functional groups have a great influence on the charging property of the toner. For example, when the polymer chain has a carboxyl group, it has a weak negative charge imparting ability.
However, if the amount of carboxyl groups present is increased, the hydrophilicity of the resin is increased and the electric charges are released to the water in the air. This tendency becomes remarkable as the number of carboxyl groups increases.

On the other hand, the acid anhydride group has a negative charge imparting ability, but has no or extremely low ability to release a charge.

Therefore, the proportion of these functional groups is important for stabilizing the chargeability of the toner. The carboxyl group acts not only on the charge release but also on the charge imparting.

On the other hand, the acid anhydride group works particularly effectively only for imparting chargeability. When a large amount of carboxyl groups are present, the amount of electric charges is increased, the charge amount of the toner is insufficient, and it becomes difficult to obtain a sufficient image density. This tendency becomes remarkable under high humidity.

On the other hand, when a large amount of acid anhydride groups are present, the amount of charge on the toner becomes excessive and the fog increases.
Especially under low humidity, this tendency intensifies and causes a decrease in image density.

Therefore, the presence of these functional groups at an appropriate ratio can balance the charge imparting and the charge releasing, stabilize the chargeability of the toner, and affect the chargeability due to environmental changes. Can be minimized.

That is, charge is imparted in the presence of an acid anhydride group, and charge is released in the presence of a carboxyl group,
It is possible to prevent excessive charging of the toner.

To this end, it is important that the total acid value (B) derived from the acid anhydride group is 6 mgKOH / g or less. If it exceeds 6 mgKOH / g, the toner is likely to be overcharged, and the density may be reduced and fog may occur under low humidity.

Further, it is preferable that the total acid value (B) derived from the acid anhydride group is 60% or less of the total acid value (A) of the entire binder resin. When it exceeds 60%, the balance between the charge application and the charge release cannot be balanced, the charge imparting ability is improved, and the toner is likely to be overcharged.

The following are examples of vinyl monomers that give an acid value to the binder resin.

For example, unsaturated dibasic acids such as maleic acid, citraconic acid, itaconic acid, alkenylsuccinic acid, fumaric acid, mesaconic acid; maleic anhydride, citraconic anhydride, itaconic anhydride, alkenylsuccinic anhydride. Unsaturated dibasic anhydrides such as: maleic acid methyl half ester, maleic acid ethyl half ester, maleic acid butyl half ester, citraconic acid methyl half ester, citraconic acid ethyl half ester, citraconic acid butyl half ester, itaconic acid methyl ester Half ester of unsaturated dibasic acid such as half ester, alkenyl succinic acid methyl half ester, fumaric acid methyl half ester, mesaconic acid methyl half ester; unsaturated dibasic acid ester such as dimethyl maleic acid and dimethyl fumaric acid. It is.

Acrylic acid, methacrylic acid, crotonic acid,
Α, β-unsaturated acids such as cinnamic acid; crotonic anhydride,
Α, β-unsaturated acid anhydrides such as cinnamic acid anhydride, said α,
An anhydride of β-unsaturated acid and lower fatty acid; alkenylmalonic acid, alkenylglutaric acid, alkenyladipic acid,
These acid anhydrides and these monoesters are mentioned.

Among these, maleic acid, fumaric acid,
Monoesters of α, β-unsaturated dibasic acids having a structure such as succinic acid are particularly preferred.

Further, as the comonomer of the vinyl copolymer, the following may be mentioned.

For example, styrene, o-methylstyrene, m
-Methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene,
2,4-dimethylstyrene, pn-butylstyrene,
Styrene and its derivatives such as p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene and pn-dodecylstyrene; ethylene, Ethylenically unsaturated monoolefins such as propylene, butylene, isobutylene; Unsaturated polyenes such as butadiene;
Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl bromide; vinyl ester acids such as vinyl acetate, vinyl propionate and vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, methacrylic acid α-methylene aliphatic mono-monomers such as n-butyl, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate. Carboxylic acid esters;
Methyl acrylate, ethyl acrylate, acrylic acid n-
Butyl, isobutyl acrylate, propyl acrylate,
Acrylic esters such as n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N
-N- such as vinylindole and N-vinylpyrrolidone
Vinyl compounds; vinylnaphthalene compounds; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide; esters of the above α, β-unsaturated acids and diesters of dibasic acids. These vinyl monomers are used alone or in combination of two or more.

Among these, a combination of monomers that forms a styrene copolymer or a styrene-acrylic copolymer is preferable.

Further, it may be a polymer cross-linked with a cross-linkable monomer as exemplified below, if necessary.

Examples of aromatic divinyl compounds include divinylbenzene and divinylnaphthalene; examples of diacrylate compounds linked by an alkyl chain include:
Ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol acrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, and the above compounds In which the acrylate is replaced with methacrylate; examples of diacrylate compounds linked by an alkyl chain containing an ether bond include diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, and polyethylene glycol. # 400 diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate, and the acrylates of the above compounds are meta-acrylated. Include those obtained by changing the over preparative; e.g. diacrylate compounds linked with a chain containing an aromatic group and an ether bond, polyoxyethylene (2)
-2,2-bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4) -2,2-bis (4-hydroxyphenyl) propane diacrylate, and acrylates of the above compounds were replaced with methacrylate. The polyester type diacrylate compounds include, for example, the trade name MANDA (Nippon Kayaku Co., Ltd.). As the polyfunctional crosslinking agent, pentaerythritol triacrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate,
Oligoester acrylates and those obtained by replacing the acrylates of the above compounds with methacrylates; triallyl cyanurate, triallyl trimellitate.

These cross-linking agents are based on other monomer components 10
It is possible to use 0.01 to 5% by weight (more preferably 0.03 to 3% by weight) with respect to 0% by weight.

Among these crosslinkable monomers, those which are preferably used in the resin for toner from the viewpoints of fixing property and anti-offset property are aromatic divinyl compounds (particularly divinylbenzene), chains containing an aromatic group and an ether bond. Examples of the diacrylate compounds bound by

In the present invention, a vinyl monomer homopolymer or copolymer, polyester, polyurethane, epoxy resin, polyvinyl butyral, rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic carbonization. If necessary, hydrogen resin, aromatic petroleum resin, etc. may be mixed with the above-mentioned binder resin and used.

When two or more kinds of resins are mixed and used as a binder resin, a more preferable form is to mix resins having different molecular weights at an appropriate ratio.

The glass transition temperature of this binder resin is 45 to 8
0 ° C., preferably 55 to 70 ° C., number average molecular weight M
n 2,500 to 50,000, weight average molecular weight Mw1
It is preferably in the range of 10,000 to 1,000,000.

The method for synthesizing the vinyl binder resin according to the present invention includes bulk polymerization, solution polymerization, suspension polymerization,
A polymerization method such as an emulsion polymerization method can be used. When using a carboxylic acid monomer or an acid anhydride monomer, it is preferable to use a bulk polymerization method or a solution polymerization method in view of the properties of the monomer.

As an example, the following method can be given.
A vinyl copolymer can be obtained by a bulk polymerization method or a solution polymerization method using a monomer such as a dicarboxylic acid, a dicarboxylic acid anhydride, or a dicarboxylic acid monoester. In the solution polymerization method, it is possible to partially dehydrate the dicarboxylic acid and dicarboxylic acid monoester units by devising the distillation conditions when the solvent is distilled off. Further, the vinyl-based copolymer obtained by the bulk polymerization method or the solution polymerization method is further heat-treated to further dehydrate it. It is also possible to partially esterify the acid anhydride with a compound such as an alcohol.

On the contrary, the vinyl copolymer thus obtained can be partially hydrolyzed to form a dicarboxylic acid by ring-opening the acid anhydride group.

On the other hand, by using a dicarboxylic acid monoester monomer, a vinyl-based copolymer obtained by a suspension polymerization method or an emulsion polymerization method is dehydrated by heat treatment and ring-opening by a hydrolysis treatment to dicarboxylic acid from an anhydride. Can be obtained. The vinyl copolymer obtained by the bulk polymerization method or the solution polymerization method is dissolved in a monomer, and then by a suspension polymerization method or an emulsion polymerization method, a method of obtaining a vinyl polymer or a copolymer is used, A part of the acid anhydride can be ring-opened to obtain a dicarboxylic acid unit. Other resins may be mixed in the monomer at the time of polymerization, and the obtained resin may be subjected to an acid anhydride by heat treatment or an esterification of the acid anhydride by a ring-opening alcohol treatment by weak alkaline water treatment.

Since the dicarboxylic acid and dicarboxylic acid anhydride monomers have strong alternating polymerizability, the following method is preferable in order to obtain a vinyl-based copolymer in which functional groups such as anhydride and dicarboxylic acid are randomly dispersed. one of. This is a method in which a vinyl-based copolymer is obtained by a solution polymerization method using a dicarboxylic acid monoester monomer, the vinyl-based copolymer is dissolved in the monomer, and a binder resin is obtained by a suspension polymerization method. In this method, when distilling off the solvent after the solution polymerization, all or the dicarboxylic acid monoester portion can be dealcoholized and ring-closed and dehydrated depending on the treatment conditions to obtain an acid anhydride. During suspension polymerization, the acid anhydride group undergoes ring-opening by hydrolysis to give a dicarboxylic acid.

In the acid anhydride formation in the polymer, the infrared absorption of carbonyl shifts to a higher wave number side than that of the acid or ester, so that the production or disappearance of the acid anhydride can be confirmed.

In the binder resin thus obtained, the carboxyl group, the anhydride group and the dicarboxylic acid group are uniformly dispersed in the binder resin, so that the toner can be given a good charging property.

The composition of the polyester resin used in the present invention is as follows.

The polyester resin used in the present invention is
45 to 55 mol% of all components are alcohol components,
55 to 45 mol% is an acid component.

As the alcohol component, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol,
1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, hydrogenated bisphenol A, or a bisphenol derivative represented by the formula (a);

[0101]

[Chemical 1] Further, diols represented by the formula (b):

[0102]

[Chemical 2] And diols such as glycerin, sorbit, sorbitan, and the like.

As the divalent carboxylic acid containing 50 mol% or more in all the acid components, benzenedicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid and phthalic anhydride or their anhydrides; succinic acid, adipic acid, sebacine Acids, alkyl dicarboxylic acids such as azelaic acid or anhydrides thereof, and succinic acid substituted with an alkyl group having 6 to 18 carbon atoms or anhydrides thereof; fumaric acid, maleic acid, citraconic acid, itaconic acid, or the like. Examples thereof include saturated dicarboxylic acids or anhydrides thereof, and as trivalent or higher carboxylic acids, trimellitic acid, pyromellitic acid,
Examples thereof include benzophenone tetracarboxylic acid and its anhydride.

The alcohol component of the polyester resin particularly preferred in the practice of the present invention is a bisphenol derivative represented by the above formula (a), and the acid component is phthalic acid, terephthalic acid, isophthalic acid or its anhydride, and succinic acid. , N-dodecenyl succinic acid or its anhydride, dicarboxylic acids such as fumaric acid, maleic acid and maleic anhydride; and tricarboxylic acid of trimellitic acid or its anhydride.

This is because the polyester resin obtained from these acids and alcohols has good fixability as a heat roller fixing toner and is excellent in offset resistance.

The acid value is 90 or less, preferably 50.
Hereafter, it is desirable that the OH value is 50 or less, preferably 30 or less. This is because as the number of terminal groups of the molecular chain increases, the toner charging property becomes more environmentally dependent on the charging characteristics.

Furthermore, the glass transition temperature of the polyester resin obtained here is 50 to 75 ° C., preferably 55 to 65.
C., and number average molecular weight Mn 1,500 to 50,000
Preferably 2,000-20,000, weight average molecular weight Mw 6,000-100,000, preferably 10,000.
It is preferably 0 to 90,000.

In the toner for developing an electrostatic charge image of the present invention, a charge control agent can be used, if necessary, in order to further stabilize the chargeability thereof. The charge control agent is the binder resin 100.
0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight
It is preferred to use parts by weight.

Charge control agents known in the art today include the following.

To control the toner to be negatively charged,
For example, organic metal complexes and chelate compounds are effective. Examples thereof include monoazo metal complexes, aromatic hydroxycarboxylic acids, metal complexes, and aromatic dicarboxylic acid-based metal complexes. In addition, aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters,
Examples thereof include phenol derivatives of bisphenol.

The magnetic material contained in the magnetic toner of the present invention includes iron oxides such as magnetite, maghemite, and ferrite, and iron oxides containing other metal oxides; Fe, C.
Metals such as o and Ni, or these metals and A
l, Co, Cu, Pb, Mg, Ni, Sn, Zn, S
b, Be, Bi, Cd, Ca, Mn, Se, Ti, W,
Examples thereof include alloys with metals such as V, and mixtures thereof.

Conventionally, as a magnetic material, ferrosoferric oxide (F) has been used.
e₃ O_Four ), Ferric sesquioxide (γ-Fe)₂ O₃ ), Iron oxide
Lead (ZnFe₂ O_Four ), Yttrium iron oxide (Y₃ Fe
_Five O ₁₂), Iron cadmium oxide (CdFe₂ O_Four ), Oxidation
Iron Gadolinium (Gd₃ Fe_Five -O₁₂), Iron oxide copper (C
uFe₂ O_Four ), Iron oxide lead (PbFe)₁₂-O₁₉), Oxidation
Iron Nickel (NiFe₂ O_Four ), Iron neodymium oxide (Nd
Fe₂ O₃ ), Iron oxide barium (BaFe₁₂O₁₉),
Iron oxide magnesium (MgFe₂ O_Four ), Iron oxide manga
(MnFe₂ O_Four ), Lanthanum iron oxide (LaFeO
₃ ), Iron powder (Fe), cobalt powder (Co), nickel powder
(Ni) and the like are known, but according to the present invention,
Magnetic materials can be used alone or in combination of two or more
To do. A particularly suitable magnetic material for the purposes of the present invention is ferric tetroxide.
Alternatively, it is a fine powder of γ-iron sesquioxide.

These ferromagnetic materials have an average particle size of 0.1 to 2
The magnetic characteristics under the application of 10 K oersted are about 20 μm to 20 oersted coercive force and 50 to 200 eersted saturation magnetization at about μm.
Mu / g (preferably 50 to 100 emu / g) and remanent magnetization of 2 to 20 emu / g are desirable.

The magnetic material 1 was added to 100 parts by weight of the binder resin.
It is recommended to use 0 to 200 parts by weight, preferably 20 to 150 parts by weight.

A colorant may be used in the toner of the present invention, if necessary. Colorants that can be used in the toner of the present invention include any suitable pigment or dye.

Examples of the pigment include carbon black, aniline black, acetylene black, naphthol yellow, Hansa yellow, rhodamine lake, alizarin lake, red iron oxide, phthalocyanine blue and indanthrene blue. 0.1 to 100 parts by weight of resin
It is preferred to use ~ 20 parts by weight, preferably 1-10 parts by weight of pigment. Further dyes are used for the same purpose. For example, there are azo dyes, anthraquinone dyes, xanthene dyes, and methine dyes, and 0.1 to 20 parts by weight, preferably 0.3 to 10 parts by weight with respect to 100 parts by weight of the resin.
It is preferred to use parts by weight of dye.

Further, in the present invention, one or more releasing agents may be contained in the toner, if desired.

The release agent used in the present invention includes the following. Aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax and paraffin wax, and oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax or block copolymers thereof; carnauba Examples thereof include waxes containing a fatty acid ester as a main component such as wax, sazol wax and montanic acid ester wax, and those obtained by partially or completely deoxidizing fatty acid ester such as deoxidized carnauba wax.
Further, saturated linear fatty acids such as palmitic acid, stearic acid, and montanic acid, unsaturated fatty acids such as brundic acid, eleostearic acid, and valinaric acid, stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnaubayl alcohol, ceryl. Alcohol, saturated alcohols such as melicyl alcohol, polyhydric alcohols such as sorbitol, fatty acid amides such as linoleic acid amide, oleic acid amide, and lauric acid amide, methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebis Saturated fatty acid bisamides such as lauric acid amide and hexamethylene bisstearic acid amide, ethylene bis oleic acid amide, hexamethylene bis oleic acid amide, N, N'-dioleyl adipic acid amide, N, N ' Unsaturated fatty acid amides such as dioleyl sebacic acid amide, aromatic bisamides such as m-xylene bisstearic acid amide, N, N'-distearyl isophthalic acid amide, calcium stearate, calcium laurate, zinc stearate, Fatty acid metal salts such as magnesium stearate (generally called metal soap), waxes obtained by grafting aliphatic hydrocarbon wax with vinyl monomers such as styrene and acrylic acid, and behenin. Examples thereof include partial esterified products of fatty acids such as acid monoglyceride and polyhydric alcohols, and methyl ester compounds having a hydroxyl group obtained by hydrogenation of vegetable fats and oils.

The amount of the release agent used in the present invention is 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, per 100 parts by weight of the binder resin.

Further, these releasing agents are usually contained in the binder resin by a method of dissolving the resin in a solvent, raising the temperature of the resin solution, and adding and mixing while stirring, or a method of mixing at the time of kneading.

As the fluidizing agent used in the present invention, any fluidizing agent can be used as long as the fluidity can be increased by adding it to the colorant-containing resin particles as compared with before and after the addition. .. For example, vinylidene fluoride fine powder, polytetrafluoroethylene fine powder and other fluorine resin powder, wet process silica, dry process silica and other fine powder silica, silane coupling agent, titanium coupling agent, silicon oil, etc. There is a treated silica or the like which has been subjected to a surface treatment.

A preferable fluidizing agent is a fine powder produced by vapor phase oxidation of a silicon halogen compound,
It is so-called dry process silica or fumed silica and is produced by a conventionally known technique. For example, the thermal decomposition oxidation reaction of silicon tetrachloride gas in oxyhydrogen flame is utilized, and the basic reaction formula is as follows.

SiCl ₄ + 2H ₂ + O ₂ → SiO ₂ + 4HCl Further, in this manufacturing process, by using another metal halogen compound such as aluminum chloride or titanium chloride together with a silicon halogen compound, a fine composite powder of silica and another metal oxide is obtained. It is also possible to obtain the body, including them. The particle size is 0.0 as the average primary particle size.
It is desirable to be within the range of 01 to 2 μm, and it is particularly preferable to use fine silica powder within the range of 0.002 to 0.2 μm.

Commercially available silica fine powders produced by vapor phase oxidation of a silicon halogen compound used in the present invention include those commercially available under the following trade names.

AEROSIL (Japan Aerosil Co., Ltd.) 130 200 300 380 TT600 MOX170 MOX80 COK84 Ca-O-SiL (CABOT Co.) M-5 MS-7 MS-75 HS-5 EH-5 Wacker HDK N 20 V15 (WACK). -CHEMIE GMBH) N20E T30 T40 DC Fine Silica (Dow Corning Co.) Francol (Fransil) Further, treated silica obtained by hydrophobizing silica fine powder produced by vapor phase oxidation of the silicon halogen compound. It is more preferable to use fine powder. Among the treated silica fine powders, those obtained by treating the silica fine powder so that the degree of hydrophobicity measured by the methanol titration test is in the range of 30 to 80 are particularly preferable.

As a method for hydrophobizing, it is imparted by chemically treating with an organic silicon compound or the like which reacts with or physically adsorbs on the fine silica powder. As a preferred method, silica fine powder produced by vapor phase oxidation of a silicon halogen compound is treated with an organosilicon compound.

Examples of such organosilicon compounds are hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyl. Dimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, ρ-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethylethoxy. Silane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyl Disiloxane, 1,3-diphenyltetramethyldisiloxane and 2 to 12 per molecule
For example, there is dimethylpolysiloxane having siloxane units and each terminal unit having a hydroxyl group bonded to Si. These are used alone or as a mixture of two or more.

The fluidizing agent used in the present invention has a specific surface area of 30 m ² / g or more, preferably 50 m ² / g or more by nitrogen adsorption measured by the BET method, which gives good results. Fluidizing agent 0.01 per 100 parts by weight of toner
-8 parts by weight, preferably 0.1-4 parts by weight.

The metal oxide powder used in the present invention includes magnesium, zinc, aluminum, cobalt,
Examples thereof include oxides of iron, zirconium, manganese, chromium, strontium and the like, and complex metal oxides of calcium titanate, magnesium titanate, strontium titanate, barium titanate and the like. Among them, zinc oxide, aluminum oxide, cobalt oxide, manganese dioxide, strontium titanate, and magnesium titanate are preferable because they can exhibit the effects of the present invention. Particularly, strontium titanate powder is preferable.

The metal oxide powder used in the present invention has a desired particle size and particle size distribution, which is produced by, for example, a sintering method, mechanically pulverized, and then classified by air classification.

The metal oxide powder used in the present invention is the toner 1
It is preferable to use 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, relative to 00 parts by weight.

To prepare the toner for developing an electrostatic image of the present invention, a binder resin, a magnetic material, and if necessary, a colorant, a charge control agent or other additives are mixed with a mixer such as a Henschel mixer or a ball mill. Mix well, melt, knead and knead using a heat kneader such as a heating roll, kneader or extruder to make the resins compatible with each other, cool and solidify the melt-kneaded product, and then crush and solidify the solidified product. The toner of the present invention can be obtained by classifying the materials.

Further, the fluidizing agent, the metal oxide powder, the toner and the toner are thoroughly mixed by a mixer such as a Henschel mixer to obtain the electrostatic image developing developer of the present invention having the additive on the surface of the toner particles. ..

(1) Measurement of particle size distribution The particle size distribution can be measured by various methods, but in the present invention, it was measured using a Coulter counter multisizer.

That is, a Coulter counter, Multisizer II type (manufactured by Coulter) is used as a measuring device, and an interface (manufactured by Nikkaki) for outputting number distribution and volume distribution and a CX-1 personal computer (manufactured by Canon) are connected. Then, as the electrolytic solution, a 1% NaCl aqueous solution is prepared using special grade or primary grade sodium chloride. As a measuring method, a surfactant, preferably 0.1 to 5 ml of alkylbenzene sulfonate is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2
Add ~ 20 mg. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser, and a 100 μm aperture is used when measuring the toner particle size as an aperture by the Multisizer II type Coulter Counter. 13μ when measuring the particle size of inorganic fine powder
Measurement is performed using the m aperture. The volume and number of the toner and the metal oxide powder were measured, and the volume distribution and the number distribution were calculated. Then, the weight-based weight average diameter obtained from the volume distribution according to the present invention is obtained from the volume distribution.

(2) Measurement of acid value in vinyl resin The qualitative and quantitative determination of the functional group in the binder resin was carried out by infrared absorption spectrum, acid value measurement according to JIS K-0070, hydrolysis acid value measurement (total). An example is a method of applying acid value measurement).

For example, in the infrared absorption, 1780 cm ^-1
Since an absorption peak derived from the carbonyl of the anhydride appears in the vicinity, the presence of the acid anhydride is confirmed.

In the present invention, the peak of the infrared absorption spectrum refers to a peak which is clearly confirmed as a peak after 16 times integration by FT-IR having a resolution of 4 cm ^-1 . F
As a model of T-IR, for example, FT-IR1600
(Manufactured by Perkin Elmer).

Acid value measurement according to JIS K-0070 (hereinafter referred to as J
IS acid value), the acid anhydride is about 50% of the theoretical value (the acid anhydride has an acid value as a dicarboxylic acid).
Is measured.

On the other hand, in the measurement of the total acid value (A), a value substantially according to the theoretical value is measured. Therefore, total acid number (A) and J
The difference from the IS acid value is about 50% of the theoretical value, and the acid anhydride is measured as a dibasic acid. Therefore, the total acid value (B) derived from the acid anhydride per 1 g can be obtained.

Total acid value (B) = [total acid value (A) -JIS acid value] × 2 Furthermore, for example, maleic acid monoester is used as an acid component, and the solution polymerization method and the suspension polymerization method are used. When preparing a vinyl-based copolymer composition to be used as a binder resin,
The total acid value (B) is measured by measuring the JIS acid value and the total acid value (A) of the vinyl copolymer produced by the solution polymerization method, and the total acid value (B) and the solution polymerization method. From the composition ratio of the vinyl-based monomer used in step 1, the existing amount (for example, mol%) of the acid anhydride produced in the polymerization step and the solvent removal step is calculated. Further, the vinyl copolymer prepared by the solution polymerization method is dissolved in a monomer such as styrene and butyl acrylate to prepare a monomer composition, and the prepared monomer composition is subjected to suspension polymerization. At that time, a part of the acid anhydride group is opened. Based on JIS acid value, total acid value (A), monomer composition ratio of vinyl copolymer composition obtained by suspension polymerization method and addition amount of vinyl copolymer adjusted by solution polymerization method, binding The existing amount of the dicarboxylic acid group, the acid anhydride group and the dicarboxylic acid monoester group in the vinyl copolymer composition used as the resin can be calculated.

The total acid value (A) of the binder resin is determined as follows. 30 g of dioxane with 2 g of sample resin
And 10 ml of pyridine, 20 mg of dimethylaminopyridine and 3.5 ml of water are added thereto, and the mixture is heated under reflux for 4 hours with stirring. After cooling, 1/10 N KOH
The acid value obtained by neutralization titration with phenolphthalein as an indicator with a THF solution is defined as the total acid value (A). Under the condition of measuring the total acid value (A), the acid anhydride group is hydrolyzed to a dicarboxylic acid, but the acrylic acid ester group, the methacrylic acid ester group and the dicarboxylic acid monoester group are not hydrolyzed.

A 1 / 10N KOH.THF solution is prepared as follows. 1.5 g of KOH is dissolved in about 3 ml of water, and 200 ml of THF and 30 ml of water are added and stirred. If the solution is separated after standing, use a small amount of methanol,
If the solution is cloudy, add a small amount of water to make a homogeneous clear solution. Standardize the KOH / THF solution with 1/10 N HCl standard solution.

The total acid value (A) in the binder resin is 2-100.
Although it is mgKOH / g, the acid value according to JIS K-0070 of the vinyl copolymer containing the acid component in the binder resin is 1
It is preferably less than 00. JIS K-0070
When the acid value is 100 or more, a carboxyl group,
Since the density of functional groups such as acid anhydride groups is high, it becomes difficult to obtain a good charge balance, and there is a tendency for problems to occur due to the dispersibility even when diluted and used.

(3) Method for Measuring Acid Value of Polyester Resin The acid value is defined as the number of milligrams of potash of potassium required to neutralize the carboxyl groups contained in 1 g of the resin. Therefore, the acid value indicates the number of terminal groups. The measuring method is as follows. Sample 2
10 g is weighed in a 200-300 ml Erlenmeyer flask, and mixed solvent of methanol: toluene = 30: 70 about 5
Add 0 ml to dissolve the resin. A small amount of acetone may be added if the solubility is poor. Using a mixed indicator of 0.1% bromthymol blue and phenol red, titration was performed with a previously standardized N / 10 potassium-alcohol solution, and the acid value was calculated from the consumption of the alcohol potassium solution by the following calculation.

Acid value = KOH (ml number) × N × 56.1 / Sample weight (where N is a factor of N / 10 KOH) (4) Glass transition temperature Tg In the present invention, a differential thermal analysis measurement device ( DSC measuring device), DSC-7 (manufactured by Perkin Elmer Co., Ltd.).

A measurement sample is 5 to 20 mg, preferably 10
Precisely weigh mg.

This was placed in an aluminum pan, and an empty aluminum pan was used as a reference, and the measurement temperature range was 30 to 20.
The measurement is performed at a temperature rising rate of 10 ° C./min between 0 ° C. and normal temperature and normal humidity.

In this temperature rising process, an endothermic peak of the main peak in the temperature range of 40 to 100 ° C. is obtained.

The crossing point between the line at the midpoint of the baseline and the differential heat curve before and after the endothermic peak appears at this time is the glass transition temperature Tg in the present invention.

(5) Measurement of molecular weight In the present invention, the molecular weight of the chromatogram by GPC (gel permeation chromatography) is measured under the following conditions.

That is, the column was stabilized in a heat chamber at 40 ° C., and THF (tetrahydrofuran) as a solvent was passed through the column at this temperature at a flow rate of 1 ml / min to obtain a sample concentration of 0.05 to 0.6 wt. The measurement is performed by injecting 50 to 200 μl of the THF sample solution of the resin adjusted to 100%. In measuring the molecular weight of the sample, the molecular weight distribution of the sample was calculated from the relationship between the logarithmic value and the count number of a calibration curve prepared using several kinds of monodisperse polystyrene standard samples. As a standard polystyrene sample for preparing a calibration curve, for example, Pressure Chemical
Co. Made or manufactured by Toyo Soda Kogyo Co., Ltd. has a molecular weight of 6
× 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 1
0 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3.9 × 10
^It is suitable to use ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , and 4.48 × 10 ⁶ standard polystyrene samples of at least about 10 points. Also, the detector is RI
A (refractive index) detector is used.

As a column, 10 ³ to 2 × 10
^In order to accurately measure the molecular weight region of ⁶ , it is preferable to combine a plurality of commercially available polystyrene gel columns.
.mu.-styragel 500,10 manufactured by Aters Inc.
Combination of ³ , 10 ⁴ and 10 ⁵ and sho from Showa Denko KK
dex KF-80M and KF-801, 803, 80
4,805 combination, KA-802,803,804
Combination of 805 or TSKgel made by Toyo Soda
G1000H, G2000H, G2500H, G300
0H, G4000H, G5000H, G6000H, G
A combination of 7000H and GMH is preferable.

[0154]

EXAMPLES The present invention will be described below with reference to production examples and examples.

[Production Example of Strontium Titanate] 600 g of strontium carbonate and 320 g of titanium oxide were wet mixed in a ball mill for 8 hours and then filtered and dried. This mixture was molded under a pressure of 5 Kg / cm ² and calcined at a temperature of 1100 ° C. for 8 hours.

After that, it was mechanically crushed and the weight average diameter was 1.8 μm.
m, number average diameter 0.7 μm, particle size distribution [(m-D ₄ ) /
(M-D ₁ )] 2.6 strontium titanate fine powder was obtained. This is designated as strontium titanate A. An elbow jet classifier utilizing the Coanda effect was used to remove coarse powder and fine powder at the same time to obtain a weight average diameter of 1.4.
μm, number average diameter 1.0 μm, particle size distribution [(m-D ₄ ).
/ (M−D ₁ )] 1.4, strontium titanate I was obtained. The volume distribution and number distribution of strontium titanate I are shown in FIG.

In the same manner as described above, strontium titanate II to V having various particle size distributions were obtained.

[Production Example of Aluminum Oxide] Aluminum hydroxide was molded at a pressure of 1000 Kg / cm ² to give 16
It was sintered at a temperature of 00 ° C. for 2 hours. Then, by mechanical pulverization and classification with an elbow jet classifier, a weight average diameter of 4.0 μm, a number average diameter of 2.5 μm, and a particle size distribution [(m-
_{D 4) / (m-D} 1)] to give 1.6 aluminum oxide I of.

Similarly, aluminum oxides II and III having different particle size distributions were obtained.

[Production Example of Zinc Oxide] 100 parts of zinc hydroxide
It was molded at a pressure of Kg / cm ² and sintered at a temperature of 500 ° C. for 5 hours. Then, by mechanical pulverization and air classification, zinc oxide I having a weight average diameter of 1.8 μm, a number average diameter of 1.2 μm, and a particle size distribution [(m-D ₄ ) / (m-D ₁ )] 1.5 is obtained. It was

Binder Resin Production Example 1 Styrene 76.0 parts by weight Butyl acrylate 13.0 parts by weight Monobutyl maleate 11.0 parts by weight Di-tert-butyl peroxide 6.0 parts by weight It was added dropwise to 200 parts by weight of xylene heated to the reflux temperature over 4 hours. Under xylene reflux (1
Polymerization was completed at 38 to 144 ° C., and xylene was removed while raising the temperature to 200 ° C. under reduced pressure. The resin thus obtained is called resin A.

The acid value of Resin A was measured and was as follows.

[0163]

[Table 1] Resin A 30.0 parts by weight Styrene 45.0 parts by weight Butyl acrylate 20.0 parts by weight Monobutyl maleate 5.0 parts by weight Divinylbenzene 0.5 parts by weight Benzoyl peroxide 1.5 parts by weight Polyvinyl alcohol in the above mixture. Partially saponified 0.1
170 parts by weight of water having 2 parts by weight dissolved therein was added and vigorously stirred to obtain a suspension dispersion liquid. The above suspension dispersion was added to a reactor in which 50 parts by weight of water was charged and the atmosphere was replaced with nitrogen, and a suspension polymerization reaction was carried out at a reaction temperature of 80 ° C. for 8 hours. After the reaction was completed, it was washed with water, dehydrated and dried to obtain a resin.

In the obtained resin H, the monobutyl maleate unit, the maleic anhydride unit and the maleic acid unit are 73.3 mol% of maleic anhydride and 73.3 mol% of maleic anhydride, based on the total amount of 100 mol%. 6.7 mol% of the product unit and 2 of the maleic acid unit
0 mol% was present.

The acid value of Binder Resin B was determined and was as follows.

[0166]

[Table 2] The binder resin B has a glass transition point of 59 ° C., a gel content of 30%, a number average molecular weight Mn12000, and a weight average molecular weight Mw.
It was 150,000. The gel content was determined from the dry weight of the insoluble matter after 0.5 to 1.0 g of the binder resin was weighed using a Soxhlet extractor and the extraction was performed for 6 hours. The molecular weights Mw and Mn were measured using those excluding the gel content.

Binder Resin Production Example 2 Bisphenol Derivative Represented by Formula (A) 1320 parts by weight Fumaric acid 100 parts by weight Terephthalic acid 200 parts by weight Trimellitic acid 300 parts by weight The above materials were made of a thermometer and stainless steel. The mixture was placed in a 4-neck round bottom flask in a 3 liter container equipped with a stirrer, a nitrogen inlet tube made of glass, and a downflow condenser. Next, this flask was placed in a mantle heater, nitrogen gas was introduced from a glass introduction tube to maintain an inert atmosphere in the reactor,
The temperature was raised and dehydration condensation was performed at 220 to 250 ° C. The relationship between the viscosity and the molecular weight was grasped in advance, and when it reached a predetermined viscosity, it was cooled and solidified to obtain a binder resin C.

The glass transition point Tg of this binder resin C is 60.
Number average molecular weight Mn 7,800, weight average molecular weight M
The w was 22,000.

Example 1 Resin B (binder resin) 100 parts by weight Magnetic iron oxide 80 parts by weight (average particle size 0.15 μm, Hc115 Oersted, σs80 emu / g, σr11 emu / g) Low molecular weight ethylene-propylene copolymer 4 1 part by weight Monoazo complex (negative charge control agent) 2 parts by weight After premixing the above materials with a Henschel mixer,
Melt kneading was carried out at 2 ° C by a twin-screw kneading extruder. After the kneaded product is allowed to cool, it is roughly crushed with a cutter mill, crushed with a fine crusher using a jet stream, and further classified with an air classifier to obtain a weight average particle diameter (t-D ₄ ) 9 0.0 μm, number average diameter (t-D ₁ ) 7.0 μm, distribution [(t-D ₄ ).
/ (T−D ₁ )] 1.3 black fine powder (negative triboelectrically charged magnetic toner) was obtained. The volume distribution and number distribution of the obtained magnetic toner are shown in FIG.

To 100 parts by weight of this magnetic toner, 0.6 parts by weight of hydrophobic dry silica (BET 150 m ² / g) and 3.0 parts by weight of strontium titanate I were externally added with a Henschel mixer to prepare a developer (a). ).

Using the obtained developer (a), a photosensitive drum of a Canon laser copying machine NP9330 is converted into an OPC photosensitive drum, a latent image is formed with a laser after charging with a negative corona, and reversal development is performed. Image was evaluated by a modified machine modified to.

As a result, there was no fog on the white background and the maximum image density was 1.48.
The density gradation was good. In addition, the linearity which was almost satisfactory was obtained in the relationship between the developing potential and the image density.
(FIG. 2) Further, a copy test of 30,000 sheets was conducted. As a result, good results were obtained in terms of fixability.
The copied image had good image quality with almost no change from the initial image described above. Further, no scratch was observed on the surface of the organic photoconductor, and the result of measuring the thickness of the photoconductor surface layer by the use current was that the amount of abrasion of the photoconductor surface layer was as small as 1.8 μm / 10,000 sheets. Further, the particle size of the developer on the developer carrier was measured and found to be 9.6 μm in weight average particle size and 7.3 μm in number average particle size (initial weight average particle size 9.0 μm, number average particle size 6.8 μm). Almost no change in diameter or distribution,
Good results were obtained in terms of selective developability as well.

Further, the carrier memory was also small.

Further, a copying test was conducted at low temperature and low humidity (5 ° C., 10%) and high temperature and high humidity (30 ° C., 80%), and good results were obtained as in the initial stage. Further, a long-term storage test (one week storage) test was carried out at high temperature and high humidity, and good results were obtained without a decrease in concentration.

Examples 2 to 7 A developer was prepared in the same manner as in Example 1 except that the material constitution shown in Table 3 and the toner particle size were changed, and the same evaluation as in Example 1 was carried out. The good results shown in are obtained.

[0176]

[Table 3]

[0177]

[Table 4] Comparative Examples 1 to 8 A developer was prepared in the same manner as in Example 1 except that the material composition shown in Table 5 and the toner particle size were changed, and the same evaluation as in Example 1 was performed. Was obtained. The metal oxide powder used was classified in the same manner as that used in the examples.

[0178]

[Table 5]

[0179]

[Table 6]

[0180]

The developer for developing an electrostatic charge image of the present invention is excellent in developing characteristics, and particularly excellent in the effect of suppressing selective development. It is also suitable as a developer for developing a latent image formed on an OPC photoconductor using an organic photoconductive substance.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a developing potential and a copy image density when a developer other than the present invention is used, in which a solid line indicates a maximum image density of 1.4 or more and a broken line indicates The case where the density gradation is improved is shown.

FIG. 2 is a diagram showing a relationship between a developing potential and a copy image density when a developer according to the present invention is used.

FIG. 3 is a particle size distribution diagram (100 μm aperture) of the insulating magnetic toner.

FIG. 4 is a particle size distribution diagram (13 μm aperture) of the metal oxide powder.

FIG. 5 is a particle size distribution chart (13 μm) of the metal oxide powder before classification.
m aperture).

Claims (1)

[Claims] 1. The weight average particle diameter (t-D ₄ ) is ₄ to 12 μm.
m, the number average particle size (t-D ₁ ) is ₁ to 10 μm, and the ratio of (t-D ₄ ) / (t-D ₁ ) is 1.01 to 2
The insulating magnetic toner, the fluidizing agent, and the weight average particle diameter (m-D ₄ ) are 0.6 to 5 μm, and the number average particle diameter (m-D ₁ ) is 0.5 to 4 μm. , (M
The ratio of −D ₄ ) / (m−D ₁ ) is 1.0 to 2.4,
The ratio of (m−D ₄ ) / (m−D ₁ ) is (t−D ₄ ) / (t
-D ₁ ), which contains a metal oxide powder having a ratio equal to or larger than that of D ₁ ), and the amount of the metal oxide powder blended is 2 times the amount of the superplasticizer blended.
The developer for developing an electrostatic charge image is characterized in that