JPH05158278A - One-component developer - Google Patents

Abstract

PURPOSE:To provide a one-component developer used for development adopting a one-component developing system, having stable fixability and excellent anti- offsetting property and ensuring high stable image density even at the time of use over a long period of time. CONSTITUTION:The binding resin of this one-component developer consists of dispersing resin (A) which is a linear polymer in which at least one of a colorant, an electric charge controlling agent and a releasing agent has been dispersed and is a copolymer consisting of components represented by formulae I, II and resin (B) which is a crosslinked polymer obtd. by polymn. in the presence of a crosslinking agent and is a copolymer consisting of components represented by the formulae I, II. In the formula II, R1 is H or CH3 and R2 is H or 1-10C alkyl.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to electrophotography, electronic printing,
The present invention relates to a one-component developer used for electrostatic recording and the like.

[0002]

2. Description of the Related Art Conventionally, US Pat. No. 2 has been used as an electrophotographic method.
297691 specification, Japanese Patent Publication No. 42-23910,
And various methods are described in Japanese Examined Patent Publication No. 43-24748. Generally, a photoconductive substance is used to form an electric latent electrostatic image on a photoconductor by various optical means, and then the latent electrostatic image is visualized by using a developer (hereinafter referred to as a toner). The image is transferred onto paper or the like in accordance with the above conditions and then fixed by heating or pressure to obtain a copy image.

As a method for visualizing an electric latent image by using a toner, a magnetic brush method described in US Pat. No. 2,870,4033 and a cascade development described in US Pat. No. 2,618,552 are disclosed. Law and US Patent No. 29
09258 Electrically conductive magnetic toner described in the specification.
Various methods are known, including the method using.

The developing method is mainly a two-component developing method in which a mixture of iron powder called a carrier, glass bead particles, etc. and a toner is used as a developer, and a one-component developing method in which the toner alone is used as a developer. There is a method.
The toners used in these are required to have various physical and chemical properties.

The former two-component developing method is a developing method in which the toner and the carrier are mixed and stirred, and the toner is charged by frictional charging with each other. Therefore, the charging property and the transporting property are stable. However, this method consumes toner one after another, so it is necessary to maintain a constant ratio of toner to carrier.
The toner density adjustment function is required, and it is difficult to reduce the size and weight.

In the latter one-component developing method which enables downsizing and weight reduction, a magnetic one-component developing method for conveying toner by utilizing magnetic force has been devised. Further, a one-component non-magnetic developing method has been devised, in which the one-component developer is charged, conveyed, and supplied only by the developer-carrying roller member that does not use a magnet roller and can be made smaller and lighter. In particular, since it does not use magnetism, it is used for color development in some cases.

As is well known, the toner for electrostatic charge development used in these developing methods is generally composed of a resin component, a coloring component composed of a pigment or a dye, and an additive component such as a plasticizer charge control agent. There is. As the resin component, natural or synthetic resins are used alone or in a proper mixture.

However, in recent years, as the tendency toward higher image quality of copied images and long-term stability of image quality has become remarkable, the binder resin, which is a main constituent component of the toner, has a higher fixing stability and durability than ever before. Is required. JP-B-51-23354, JP-B-63-39052, JP-B-63-42252, JP-B-63-49221
Publication, Japanese Patent Publication No. 63-52375, Japanese Patent Publication No. 1-1
Japanese Patent No. 7579 proposes a toner using a cross-linked polymer as a binder resin, and provides a toner having excellent fixability and impact resistance and excellent durability.

[0009]

However, the above configuration has the following problems.

Many toners which are easily melted by heating are likely to be caked or agglomerated during storage or in the developing device of a copying machine. Also, with many toners, due to repeated development due to continuous use for a long period of time, the toner particles collide with members inside the developing device and are impacted by stress from the layer regulation member, etc. The image density obtained by physical or electrostatic deterioration is lowered, or the background density is increased, and the quality of the copied image is lowered.

These undesired phenomena are often due to the brittleness of toner particles. That is, it relates to the life of the developer, and in particular, the toner particles in the developing device are transported to the developing area facing the electrostatic latent image by the developer carrying roller member, layer regulating blade, developing roller, etc. Receive a lot of stress from. This stress causes the toner
The particles are destroyed and the fine powder particles increase, or the hydrophobic silica particles externally treated on the resin surface are driven into the resin, so that the toner particles are deteriorated and the developing characteristics are deteriorated. In order to avoid such a deterioration phenomenon, it has been proposed to use the above-mentioned crosslinkable high molecular weight polymer. However, if the crosslinking temperature is simply crosslinked, the fixing temperature in the heat fixing step which is the final step of copying is Rise and need more heat. Further, in a crosslinked high-viscosity type polymer, when the pigment is kneaded and dispersed in the resin, it is difficult to sufficiently disperse the pigment, so that the toner using the crosslinked polymer as a binder resin obtains good developing characteristics. It has the drawback of being difficult. On the other hand, attempts have been made to improve these problems by mixing a crosslinked polymer and another resin, but this alone does not provide sufficient dispersibility. This is because a high-viscosity resin such as a crosslinked polymer impedes the wettability between the resin and an internal additive such as a pigment during kneading.

When the internal additives such as pigments are poorly dispersed, particles having good dispersion are used for development during long-term use, and particles having poor dispersion remain in the developing device for selective development, which is a toner property. Cause deterioration.

In view of the above problems, the present invention is excellent in stable fixing property, offset resistance and stress resistance, does not cause agglomeration and is excellent in fluidity, and has good internal additives such as pigments. It is an object of the present invention to provide a stable one-component developer which can be dispersed in the emulsion, has stable developability, has a high image density, and is free from fog.

[0014]

In order to achieve this object, the present invention provides a linear polymer (a linear polymer of the present invention in which internal additives such as a colorant, a charge control agent and a release agent can be uniformly dispersed. A polymer has a chain molecular structure and means a polymer that has not been crosslinked) to make a dispersion resin, and then mix this dispersion resin with a crosslinked polymer with strong stress resistance. As a result, the internal additive is uniformly dispersed, durability is obtained, and fixability is not impaired.

That is, the one-component developer of the present invention carries an electrostatic latent image carrier for carrying an electrostatic latent image, a developer hopper for containing the developer, and a developer while frictionally charging the developer. One component used in a developing device having a developer carrying roller member for carrying, a developing roller for carrying the developer to a developing area facing the electrostatic latent image, and an elastic member for layer-regulating and thinning the layer of the developer A binder, which is a one-component developer, in which at least one of a colorant, a charge control agent, and a release agent is dispersed, and has a weight average molecular weight of 10,000 to 200,000.
Is a linear polymer having a weight average molecular weight / number average molecular weight of less than 10 and is a copolymer (styrene-acrylate or styrene-methacrylate copolymer) consisting of at least (Chemical formula 1) and (Chemical formula 2). Dispersion resin A and 130
Melt viscosity at ℃ 1 × 10 ⁵ to 1 × 10 ⁷ (poise)
And the melt viscosity at 160 ° C. is 1 × 10 ⁴ to 1 × 10 ⁶
(poise) is a cross-linked polymer obtained by polymerization in the presence of a cross-linking agent, and is a copolymer (styrene-acrylate or styrene-methacrylate-based copolymer) composed of at least (Chemical Formula 1) and (Chemical Formula 2) The resin B is 5 to 45% by weight and the resin B is 95 to 55% by weight based on the weight of the one-component developer.

[0016]

[Chemical 3]

[0017]

[Chemical 4]

[0018]

The present invention will be described in detail below.

The binder resin for the one-component developer of the present invention is a vinyl polymer obtained by polymerizing or copolymerizing vinyl monomers. Examples of the styrene as a monomer constituting the linear polymer and the crosslinked polymer of the binder resin component include styrene, α-methylstyrene, styrene such as P-chlorostyrene and its substitutes, and an alkyl acrylate such as acrylic acid. , Methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, isobutyl acrylate, isobutyl acrylate, hexyl acrylate, phenyl acrylate, methacrylic acid alkyl esters such as methacrylic acid, methacrylic acid Examples include monocarboxylic acids having a double bond such as methyl, ethyl methacrylate, butyl methacrylate, octyl methacrylate, isobutyl methacrylate, dodecyl methacrylate, and hexyl methacrylate, and their substitution products.

Further, the crosslinked polymer of the present invention is a polymer synthesized mainly from a vinyl-based monomer containing 0.1 to 10% by weight of the crosslinking agent monomer based on the weight of the monomer. Examples of compounds having two or more bonds include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene, and diethylenic carboxylic acid esters such as ethylene glycol, tetraethylene glycol and dimethacrylate. As a method for producing these polymers, desired known polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization are adopted, and the catalyst has sufficient catalytic ability such as benzoyl peroxide and azobisisobutylnitrile. A catalyst that has is used. Further, for the purpose of adjusting the molecular weight, a chain transfer agent which gives a desired result such as triethylamine, carbon tetrachloride, carbon tetrabromide, n-butyl mercaptan and the like can be used. The linear polymer of the present invention has a weight average molecular weight (hereinafter referred to as Mw) of 10,000.
It is preferable that the ratio of the number average molecular weight (hereinafter referred to as Mn) to Mw, that is, Mw / Mn is less than 10 in the range of up to 200,000. If the Mw is 10,000 or less, the toner tends to aggregate, the stress resistance of the toner decreases, and silica is apt to be implanted, resulting in deterioration of fluidity during long-term use. When it is 200,000 or more, the fixing property is deteriorated, and the viscosity is increased, so that the dispersibility of the internal additive such as the pigment at the time of kneading is deteriorated, the pulverizability is deteriorated, and the yield is decreased.

The average molecular weight of the resin is a value measured by gel permeation chromatography using several kinds of monodisperse polystyrene as standard samples.

The crosslinked polymer of the present invention has a melt viscosity of 13
1 × 10 ⁵ to 1 × 10 ⁷ (poise) at 0 ° C., 160 ° C.
In the above, 1 × 10 ⁴ to 1 × 10 ⁶ (poise) is preferable.
Melt viscosity characteristics: 1 × 10 ⁷ (poise) at 130 ℃, 160 ℃
When it is 1 × 10 ⁶ (poise) or more, the compatibility with the linear polymer decreases and the dispersibility of the internal additive also becomes non-uniform. Further, a high fixing temperature is required during fixing.

The melt viscosity characteristic at 130 ° C. is 1 × 10 ⁵ (pois
e), stress resistance decreases at 160 ° C. of 1 × 10 ⁴ (poise) or less, and flowability decreases due to implantation of silica.
This leads to deterioration of developability.

The melt viscosity at this time was measured with a Koka type flow tester (manufactured by Shimadzu Corporation) under the conditions of soybean dimension of 1 × 9 mm and extrusion pressure of 10 kg / cm ² .

The one-component toner of the present invention is preferably such that the total amount of the dispersion resin A and the resin B is 5 to 45% by weight of the dispersion resin A and 95 to 55% by weight of the resin B. When the content of the dispersed resin A is less than 5% by weight and the content of the resin B is 95% by weight or more, the fixing property is deteriorated and the pulverizability is deteriorated, which is not preferable.
Further, when the content of the dispersed resin A is 45% by weight or more and the content of the resin B is less than 55% by weight, stress resistance is lowered, and developability and fluidity are deteriorated, which is not preferable.

The purpose of blending the dispersion resin A and the resin B is to knead the linear polymer with an internal additive such as a pigment as a colorant so that the pigment has good wettability and is uniformly dispersed in the linear polymer. To produce the dispersed resin. Furthermore, when the dispersion resin and the cross-linked polymer are mixed, the pigment is uniformly dispersed in the resin, so that the uniform dispersibility can be maintained even in the cross-linked polymer. The linear polymer and crosslinked polymer used in the present invention contain styrene in an amount of 50 to 100% by weight, particularly preferably 6%.
0 to 95% by weight is included as a component. When the proportion of styrene is less than 50% by weight, the toner has poor heat melting property and insufficient fixing property.

The dispersion resin A in the binder resin of the present invention is a linear polymer in which at least one of a colorant, a charge control agent and a release agent is dispersed. As a method of dispersion, a method of dispersing a linear polymer in the process of polymerizing from a monomer by a known polymerization method, a method of mixing with a linear polymer and dispersing by heating and kneading, and a method of roughly crushing the lump with a cutter mill or the like Etc. As the heating and kneading method at this time, a known heating and kneading machine can be used. As a heating kneader,
It is possible to use a device for heating a kneaded material such as a three-roll type, a single screw type, a twin screw type, a banbury mixer type, and applying a shearing force to knead the mixture. In this experiment, PCM30 manufactured by Ikegai Tekko KK was used. The present invention is not limited to this.

The method of mixing the dispersion resin A and the crosslinked polymer resin B is obtained by dissolving the dispersion resin A in a monomer for crosslinked polymer and then carrying out polymerization to obtain a crosslinked polymer. Be done. Further, there is a method in which the dispersion resin A and the crosslinked polymer resin B powder are mixed and mixed by heating and kneading.

Then, it is pulverized by a jet mill pulverizer, fine powder particles are cut by an air stream classifier to obtain a desired particle size distribution, and an external additive such as silica is externally added to obtain a toner.

The one-component developer according to the present invention has the resin as the main component as described above, but other known polymers may be mixed and used in addition to the main component as required. For example, epoxy resin, polyester resin,
Polyurethane resin etc. are available.

Further, the one-component developer according to the present invention is colored and
Appropriate pigments or dyes are blended for the purpose of charge control.
Such pigments or dyes include carbon black,
There are iron black, graphite, nigrosine, quaternary ammonium salts, metal complexes of azo dyes, phthalocyanine blue, cerco oil blue, DuPont oil red, aniline blue, benzidine yellow, rose bengal and mixtures of these. The required amount is blended.

Further, the one-component developer according to the present invention may further contain a release agent if necessary. Further, other kinds of additives can be blended if necessary. Examples thereof include external additives such as silica, titanium and alumina, and abrasives such as tin oxide and strontium titanate.

Further, in the one-component developer according to the present invention, a magnetic material is blended if necessary. Examples of the magnetic powder include metal powder such as iron, manganese, nickel and cobalt, and ferrite such as iron, manganese, nickel, cobalt and zinc. The average particle size of the powder is 10 μm or less, particularly preferably 7 μm
m or less is preferable.

According to the present invention having the above-mentioned constitution, an internal additive such as a colorant is dispersed in a linear polymer, and a dispersion resin A in which the internal additive such as the colorant is dispersed and a resin B of a crosslinked polymer. By mixing, the internal additives such as pigments in the binder resin are uniformly dispersed, the toner charge amount distribution becomes sharp, and the transportability from the developer carrying roller member to the developing roller is high,
It is possible to provide a stable one-component developer which has a high image density and is free from fog during long-term use. The molecular weight characteristics of the linear polymer are Mw of 10,000 to 200,000 and Mw / Mn of 10
The melt viscosity at 130 ° C is 1 × 10 ⁵
~ 1 × 10 ⁷ (poise), the melt viscosity at 160 ℃ is 1
The mixing ratio of the cross-linked polymer defined by × 10 ⁴ to 1 × 10 ⁶ (poise) is 5% of the dispersion resin A based on the weight of the one-component developer.
-45% by weight and resin B of 95-55% by weight make it possible to maintain high stress resistance, stable fixability, and stable development characteristics even when used for a long period of time with stable development characteristics. Will be obtained.

[0035]

Embodiments of the present invention will now be described with reference to the drawings. The present invention is not limited to this.

FIG. 1 shows an example of a developing device in which the one-component developer of the present invention is used. Developing roller 1 is developing device 2
Part of which is exposed at the tip of the and faces the photoconductor drum with an appropriate gap. The photoconductor drum 3 is a so-called organic photoconductor in which a photoconductive layer made of an organic photoconductive material is formed on the surface of a metal base such as aluminum, and the surface of the organic photoconductor is charged as shown by an arrow E _X. The image is exposed to the image to form an electrostatic latent image. The photosensitive drum is not limited to the organic photoconductive material, and Se, CdS, aS
An inorganic photoconductive material such as i may be used.

The developing roller 1 is composed of a metal roller made of aluminum, the surface of which is sandblasted so as to easily carry the developer, and the developer carrying roller member 4 (in the present invention, a fur brush is used) in the developing device 2 is used. The one-component developer 5 is supplied. The developing roller is not limited to aluminum, but may be a roller made of metal or the like that has been surface-treated so as to easily carry and convey the developer. The developer carrying roller member is not limited to the fur brush, but may be sponge or metal. A roller-shaped member that can carry and convey the agent may be used. Behind the developer carrying roller member (fur brush) 4, there is a developer hopper 6, and the developer 5 in the developer hopper 6 is agitated by a developer supply paddle 7 while the developer carrying roller member 4 side. Sent to. The developer-carrying roller member 4 carries the sent-out developer 5 while stirring and conveys it to the developing roller 1 side, and mainly to the developing roller 1 while frictionally charging the developer 5 with the developing roller 1. Supply. The developing roller 1 carries the supplied developer 5 on its surface and conveys it to the photoconductor drum 3 side. During this conveyance, the elastic blade 8 is pressed against the surface of the developing roller 1. The elastic blade 8 is made of a rubber blade such as urethane rubber or silicon rubber, or a blade made of an appropriate metal, and presses the developer 5 supplied onto the developing roller 1 to form a uniform layer having a predetermined layer thickness. A thin layer is formed so that the electrostatic latent image on the photosensitive drum 3 can be stably developed. For this development, a developing bias is applied to the developing roller 1 by the DC power supply 9, and the developing roller 1
The upper developer 5 is often attached to the electrostatic latent image on the photosensitive drum 3. Since the development in this embodiment is so-called reversal development, the developer 5 is attached to the portion of the photoconductor drum 3 where the charge is removed by image exposure to form a visible image.

Next, the material composition of the developer and the manufacturing method will be described. All parts in the examples are parts by weight. Further, all the monomer ratios in the examples are% by weight. Example 1 The material composition of the toner-a1 used in Example 1 is shown. The material composition of the dispersed resin A is shown in (Table 1), and the characteristics of the resin B are shown in (Table 2).

[0039]

[Table 1]

[0040]

[Table 2]

The mixture of the dispersion resin A shown in Table 1 was kneaded by heating with a twin-screw extruder (PCM30 manufactured by Ikegai Iron Works Co., Ltd.) and coarsely pulverized with a cutter mill to prepare a dispersion resin A. (Table 2)
The crosslinked polymer resin B shown in 1) was produced by a suspension polymerization reaction in the presence of styrene, a butyl acrylate monomer and a divinylbenzene crosslinking agent.

Toner a1 is 26 parts by weight of dispersed resin A and resin B
74 parts by weight are mixed and kneaded by heating with a twin-screw kneading extruder,
Fine pulverization was performed with a jet mill, and fine powder was cut with an air stream classifier to obtain particles having an average particle size of 5 to 30 μm. After that, as a process of external addition, the toner base prepared as described above and the hydrophobic silica are mixed in a Henschel mixer and externally added.
Finally, the aggregate was extracted with a vibrating screen to complete toner a1. At this time, 1.5 parts by weight of hydrophobic silica was added as an external additive.

This is a digital copying machine (Matsushita Electric) "F
A copying test was performed on 10,000 sheets by "P-C1", and the image density was measured by a reflection densitometer (Macbeth Co.) and evaluated. A high-concentration image with a reflection density of 1.4 was obtained in the initial image, and the dispersion of the pigment was good and no aggregates were seen,
Also, the decrease in fluidity of the toner after 10,000 sheets is small,
A high density copy was obtained which was comparable to the initial image. Table 5 shows the transition of the image density of each toner. Comparative Example 1 The material composition of the toner a2 used in Comparative Example 1 is shown in (Table 3).

[0044]

[Table 3]

A linear polymer was not used, only a cross-linked polymer was used as a binder resin, the mixture shown in (Table 3) was heated and kneaded by a twin-screw kneading extruder, and finely pulverized by a jet mill. Fine powder was cut with an airflow classifier to obtain particles having an average particle size of 5 to 30 μm. After that, as a process of external addition, the toner base prepared as described above and the hydrophobic silica are mixed in a Henschel mixer and externally added. Finally, the agglomerates were extracted with a vibrating screen to complete toner a2. At this time, 1.5 parts by weight of hydrophobic silica was added as an external additive.

This is a digital copying machine (made by Matsushita Electric) "F
A copying test was performed on 10,000 sheets by "P-C1", and the image density was measured by a reflection densitometer (Macbeth Co.) and evaluated. The image density from the beginning was low, and a practical image could not be obtained. At this time, the internal additive of the toner was not well dispersed, and many aggregates of carbon black were observed. Comparative Example 2 The material composition of the toner-a3 used in Comparative Example 2 is shown in (Table 4).

[0047]

[Table 4]

A linear polymer alone was used as a binder resin without using a cross-linked polymer, the mixture shown in (Table 4) was heated and kneaded by a twin-screw kneading extruder, and finely pulverized by a jet mill. Fine powder was cut with an airflow classifier to obtain particles having an average particle size of 5 to 30 μm. After that, as a process of external addition, the toner base prepared as described above and the hydrophobic silica are mixed in a Henschel mixer and externally added. Finally, the agglomerates were extracted with a vibrating screen to complete toner a3. At this time, 1.5 parts by weight of hydrophobic silica was added as an external additive.

This is a digital copying machine (Matsushita Electric) "F
A copying test was performed on 10,000 sheets by "P-C1", and the image density was measured by a reflection densitometer (Macbeth Co.) and evaluated. Table 5 shows the change in image density of each toner.

Although the initial image density was high, it was 200
The image density gradually decreased from about 0 sheets, and a practical image could not be obtained. At this time, observing the fluctuation state of the fluidity of the toner, it was observed that the toner a3 of Comparative Example 2 showed a large decrease in fluidity as compared with the toner a1 used in Example 1. SEM (scanning electron microscope)
As a result of observing the toner surface, it was observed that many silica particles were driven into the resin. The fluidity was evaluated using a powder tester manufactured by Hosokawa Micron.

[0051]

[Table 5]

Example 2 The material composition of the toner-b1 used in Example 2 is shown. Table 6 shows the material composition of the dispersed resin A, and Table 7 shows the characteristics of the resin B.

[0053]

[Table 6]

[0054]

[Table 7]

The mixture of the dispersion resin A in Table 6 was kneaded by heating with a twin-screw extruder (PCM30 manufactured by Ikegai Iron Works Co., Ltd.) and coarsely pulverized with a cutter mill to prepare a dispersion resin A. (Table 7)
The crosslinked polymer resin B shown in 1) was produced by a suspension polymerization reaction in the presence of styrene, a butyl acrylate monomer and a divinylbenzene crosslinking agent.

Toner b1 comprises 26 parts by weight of dispersed resin A and resin B
74 parts by weight are mixed and kneaded by heating with a twin-screw kneading extruder,
Fine pulverization was performed with a jet mill, and fine powder was cut with an airflow classifier to obtain particles having an average particle size of 5 to 300 μm.
After that, as a process of external addition, the toner base prepared as described above and the hydrophobic silica are mixed in a Henschel mixer and externally added. Finally, the aggregate was extracted with a vibrating screen to complete the toner b1. At this time, 1.5 parts by weight of hydrophobic silica was added as an external additive.

This is a digital copying machine (made by Matsushita Electric) "F
A copying test was performed on 10,000 sheets by "P-C1", and the image density was measured by a reflection densitometer (Macbeth Co.) and evaluated. A high-concentration image with a reflection density of 1.4 was obtained in the initial image, and the dispersion of the pigment was good and no aggregates were seen,
Also, the decrease in fluidity of the toner after 10,000 sheets is small,
A high density copy was obtained which was comparable to the initial image. Comparative Example 3 The material composition of the toner b2 used in Comparative Example 3 is shown in (Table 8).

[0058]

[Table 8]

A linear polymer was not used, only a cross-linked polymer was used as a binder resin, the mixture shown in (Table 8) was heated and kneaded by a twin-screw kneading extruder, and finely pulverized by a jet mill. Fine powder was cut with an airflow classifier to obtain particles having an average particle size of 5 to 30 μm. After that, as a process of external addition, the toner base prepared as described above and the hydrophobic silica are mixed in a Henschel mixer and externally added. Finally, the aggregate was extracted with a vibrating screen to complete the toner b2. At this time, 1.5 parts by weight of hydrophobic silica was added as an external additive.

This is a digital copier (Matsushita Electric) "F
A copying test was performed on 10,000 sheets by "P-C1", and the image density was measured by a reflection densitometer (Macbeth Co.) and evaluated. The image density from the beginning was low, and a practical image could not be obtained. At this time, the internal additive of the toner was not well dispersed, and many aggregates of carbon black were observed.

Further, the use of a highly viscous crosslinked polymer also deteriorated the fixing property. Comparative Example 4 The material composition of the toner-b3 used in Comparative Example 4 is shown in (Table 9).

[0062]

[Table 9]

Using a linear polymer alone as a binder resin without using a cross-linked polymer, the mixture shown in (Table 9) was heated and kneaded with a twin-screw kneading extruder, and finely pulverized with a jet mill. Fine powder was cut with an airflow classifier to obtain particles having an average particle size of 5 to 30 μm. After that, as a process of external addition, the toner base prepared as described above and the hydrophobic silica are mixed in a Henschel mixer and externally added. Finally, the aggregate was extracted with a vibrating screen to complete toner b3. At this time, 1.5 parts by weight of hydrophobic silica was added as an external additive.

This is a digital copying machine (made by Matsushita Electric) "F
A copying test was performed on 10,000 sheets by "P-C1", and the image density was measured by a reflection densitometer (Macbeth Co.) and evaluated. Table 10 shows the change in image density of each toner.

Although the initial image density was high, it was 400
The image density gradually decreased from about 0 sheets, and a practical image could not be obtained. At this time, observing the fluctuation state of the fluidity of the toner, it was observed that the toner b3 of Comparative Example 4 showed a large decrease in fluidity as compared with the toner b1 used in Example 2. When observing the surface of the toner by SEM, it was observed that many silica particles were driven into the resin.

[0066]

[Table 10]

[0067]

INDUSTRIAL APPLICABILITY As described above, the present invention provides a colorant and a charge control agent.
Weight average amount of at least one of the control agent and the release agent dispersed.
Molecular weight of 10,000 to 200,000 and weight average molecule
Weight / number average molecular weight less than 10 styrene-acrylate
Or a styrene-methacrylate linear copolymer
Dispersion resin A with a melt viscosity at 130 ° C. of 1 × 10
^Five~ 1 x 10⁷(poise), the melt viscosity at 160 ℃
1 x 10^Four~ 1 x 10⁶(poise) in the presence of crosslinker
Styrene-acrylate or styrene-obtained by
Containing a resin B, which is a methacrylate-based cross-linked copolymer
By using a one-component developer composed of a binder resin
Therefore, the internal additives such as colorants in the binder resin can be dispersed uniformly.
The toner charge amount distribution becomes sharp and high image density
Obtained, can maintain high stress resistance, and during long-term continuous use
Even if there is no deterioration in fluidity, a stable image with no fog
Will be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of a developing mechanism in which a developer according to an embodiment of the present invention is used.

[Explanation of symbols]

 1 Developing Roller 2 Developing Device Main Body 3 Photosensitive Drum 4 Developer Bearing Roller Member 5 Developer 6 Developer Storage Chamber 7 Developer Supply Paddle 8 Elastic Blade 9 DC Power Supply

Claims (1)

[Claims] 1. An electrostatic latent image carrier for carrying an electrostatic latent image, a developer hopper for containing a developer, and a developer carrying roller member for carrying and carrying the developer while frictionally charging the developer. And a developing roller that conveys the developer to a developing area facing the electrostatic latent image, and a one-component developer used in a developing device that includes an elastic member that regulates the layer of the developer and thins the layer. The binder resin of the one-component developer is a colorant, a charge control agent,
A linear polymer having a weight average molecular weight of 10,000 to 200,000 and a weight average molecular weight / number average molecular weight of less than 10 in which at least one release agent is dispersed, and at least from the general formulas (Formula 1) and (Formula 2) And a dispersion resin A which is a copolymer (styrene-acrylate or styrene-methacrylate-based copolymer) having a melt viscosity at 130 ° C. of 1 × 10 ⁵ to 1 × 10 ⁷ (poise) and a melt viscosity at 160 ° C. It is a cross-linked polymer obtained by polymerizing at 1 × 10 ⁴ to 1 × 10 ⁶ (poise) in the presence of a cross-linking agent, and is a copolymer (styrene) having at least general formulas (Chemical Formula 1) and (Chemical Formula 2). Resin-B, which is a styrene-acrylate or styrene-methacrylate copolymer), and the dispersion resin A is 5 to 45% by weight and the resin B is 95 to 55% by weight based on the weight of the one-component developer. One-component developer which is characterized in that. [Chemical 1] [Chemical 2]