JP2021051236A - Electrophotographic photoreceptor and electrophotographic image forming device - Google Patents

Abstract

To provide an electrophotographic photoreceptor capable of forming an image excellent in abrasion resistance, white background contamination resistance and fine line reproducibility while maintaining high image quality, and also to provide an electrophotographic image forming device equipped with the same.SOLUTION: Disclosed is an electrophotographic photoreceptor having a protective layer which contains at least a resin and metal oxide particles. The metal oxide particle is surface-modified with a surface modifier and a compound having the same structural portion as a residue of the surface modifier is contained in the resin separately from the surface modifier modifying the surface of the metal oxide particle.SELECTED DRAWING: Figure 4

Description

The present invention relates to an electrophotographic photosensitive member and an electrophotographic image forming apparatus. More specifically, the present invention can form an image having excellent wear resistance, white background contamination resistance, and fine line reproducibility while maintaining high image quality. It relates to a body and an electrophotographic image forming apparatus equipped with the body.

In recent years, due to the increasing demand for high-definition and high-quality images, toner having a small particle size has become the mainstream. A toner having a small particle size has a large adhesive force to the surface of an electrophotographic photosensitive member (hereinafter, also simply referred to as a photoconductor), and the removal of residual toner such as transfer residual toner adhering to the surface tends to be insufficient.

In the cleaning method using a rubber blade, toner slips through and stains are likely to occur in the white background area. To solve this, it is necessary to increase the contact pressure of the blade with the photoconductor, but it is repeated. The use causes a problem that the surface of the photoconductor is worn and the durability is insufficient.

In response to the above problem, as method A, as a means for reducing the adhesive force between the surface of the photoconductor and the toner and improving the cleanability, fluorinated fine particles and a fluorinated lubricant are added to the surface layer of the photoconductor in Patent Document 1. Further, Patent Document 2 discloses a method of adding a silicone-based lubricant or the like. However, these proposed fluorine-based and silicone-based lubricants tend to cause a decrease in surface hardness when the amount added to the surface layer (protective layer) is increased. Further, due to its high surface transferability, fluorine-based or silicone-based materials tend to be present in a high concentration only in the very surface layer region of the electrophotographic photosensitive member, and although they initially show high cleaning properties, they are repeatedly used for a long period of time. As a result, the surface of the photoconductor is scraped off, the high cleaning property is reduced, and it is difficult to obtain a sufficient effect.

On the other hand, as a method B for improving the wear resistance of the photoconductor, a method of adding metal oxide fine particles to the surface layer further improves the dispersibility of the metal oxide fine particles and suppresses image blurring under high humidity. For this purpose, a method of surface-modifying metal oxide fine particles is disclosed (see, for example, Patent Document 3). However, in the method proposed in Patent Document 3, a new problem arises in which image flow occurs due to the proximity of highly conductive metal oxide fine particles, resulting in deterioration of fine line reproducibility.

Further, as a method C for achieving both high cleaning property and abrasion resistance, a method of using organic resin fine particles or a surface modifier (lubricant) in combination with surface-modified metal oxide particles is disclosed (). For example, see Patent Document 4 and Patent Document 5). However, in the method C, there is a problem that these surface modifiers segregate on the surface side of the photoconductor, the metal oxide particles tend to aggregate, and cleaning failure occurs on the contrary.

Therefore, there is a need for the development of an electrophotographic photosensitive member capable of forming an image having excellent wear resistance, white background contamination resistance, and fine line reproducibility while maintaining high image quality.

Japanese Unexamined Patent Publication No. 63-73267 Japanese Unexamined Patent Publication No. 5-323646 Japanese Unexamined Patent Publication No. 2012-98591 Japanese Unexamined Patent Publication No. 2000-122329 Japanese Unexamined Patent Publication No. 2015-114453

The present invention has been made in view of the above problems and situations, and the problem to be solved is an electron capable of forming an image having excellent wear resistance, white background contamination resistance, and fine line reproducibility while maintaining high image quality. It is to provide a photographic photosensitive member and an electrophotographic image forming apparatus provided with the photographic photosensitive member.

In the process of examining the cause of the above problem in order to solve the above-mentioned problems, the present inventor presents the metal oxide particles on the surface of the protective layer containing at least the resin and the metal oxide particles by a surface modifier. The image quality of the electrophotographic photosensitive member, which is modified and is characterized by containing a compound having the same structural portion as the residue of the surface modifier, in the resin other than the surface of the metal oxide particles. We have found that it is possible to provide an electrophotographic photosensitive member capable of forming an image having excellent wear resistance, white background contamination resistance and fine line reproducibility while maintaining the above conditions, and have arrived at the present invention.

That is, the above-mentioned problem according to the present invention is solved by the following means.

1. 1. An electrophotographic photosensitive member having a protective layer containing at least a resin and metal oxide particles.
The metal oxide particles are surface-modified with a surface modifier, and the metal oxide particles are surface-modified.
Apart from the surface modifier that modifies the surface of the metal oxide particles, the resin contains a compound having the same structural portion as the residue of the surface modifier. Photophotoreceptor.

2. The content of the compound having the same structural portion as the residue of the surface modifier in the resin is in the range of 0.01 to 0.5 parts by mass with respect to 1 part by mass of the resin. The electrophotographic photosensitive member according to the first item.

3. 3. The content of the compound having the same structural portion as the residue of the surface modifier in the resin is in the range of 0.02 to 0.25 parts by mass with respect to 1 part by mass of the resin. The electrophotographic photosensitive member according to the first or second paragraph.

4. The surface of the protective layer has a plurality of protrusions and has a plurality of protrusions.
Any one of the first to third terms, wherein the average distance R between the convex portions of the convex portion structures adjacent to each other is within the range of 100 to 250 nm among the plurality of convex portions. The electrophotographic photosensitive member according to.

5. The electrophotographic photosensitive member according to any one of items 1 to 4, wherein the protective layer contains a polymerized cured product of a composition containing a polymerizable monomer and metal oxide particles.

6. The electrophotographic photosensitive member according to any one of items 1 to 5, wherein the surface modifier has an alkyl fluoride chain.

7. The electrophotographic photosensitive member according to Item 6, wherein the alkyl fluoride chain is contained in the side chain of the surface modifier.

8. The electrophotographic photosensitive member according to any one of items 1 to 5, wherein the surface modifier has a silicone chain.

9. The electrophotographic photosensitive member according to Item 8, wherein the silicone chain is provided on the side chain of the surface modifier.

10. The electrophotographic photosensitive member according to any one of items 1 to 9, wherein the metal oxide particles have a polymerizable group.

11. An electrophotographic image forming apparatus comprising the electrophotographic photosensitive member according to any one of items 1 to 10.

An electrophotographic photosensitive member capable of forming an image having excellent wear resistance, white background contamination resistance, and fine line reproducibility while maintaining high image quality by the above means of the present invention, and an electrophotographic image forming apparatus provided with the electrophotographic photosensitive member. Can be provided.

Although the mechanism of expression or mechanism of action of the effect of the present invention has not been clarified, it is inferred as follows.

The features of the protective layer according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view showing an example of the structure of a protective layer of a comparative example containing a surface modifier and a protective layer of the present invention.

The protective layer 11 shown in FIG. 1A has a structure in which only the surface modifier 12 (also referred to as a lubricant) is contained in the resin 13 which is a binder (corresponding to the method A). In this configuration, a fluorine-based or silicone-based surface modifier having a strong surface orientation (or migration) property tends to be present in a high concentration only in the surface layer region S of the protective layer due to its high surface orientation (or migration) property. Although the initial cleaning property is high, the surface of the photoconductor is scraped by repeated use over a long period of time, the high cleaning property is reduced, and it is difficult to obtain a sufficient effect.

The protective layer 11 shown in FIG. 1B is a surface-modified metal oxide particle formed by applying a surface modifier 16 to the surface of the metal oxide particle (also referred to as an inorganic filler) 15 in the resin 13. (Hereinafter, referred to as “surface-modified particles”) This is an example in which 14A is contained. In the case of this example, image flow is likely to occur due to the proximity of the surface-modified particles 14A having high conductivity to each other, and image blurring and deterioration of fine line reproducibility are likely to occur.

The protective layer 11 shown in FIG. 1 (c) is an example in which the surface modifier 12 and the surface modifier particles 14B to which the surface modifier 17 is applied to the surface of the metal oxide particles 15 are contained in the resin 13. Is. In this example, when the structure of the surface modifier 12 contained in the resin 13 and the structure of the residue portion of the surface modifier adsorbed on the surface of the metal oxide particles are compared, the same structural portion is common. It was found that when there is no portion, the surface modifier 12 existing in the resin 13 segregates into the surface region S of the protective layer 11, and the surface modifier particles 14B are likely to aggregate, resulting in poor cleaning. ..

Based on the above problems and findings, in the protective layer according to the present invention, as shown in FIG. 1 (d), a compound having the same structural portion as the residue of the surface modifier 16 adsorbed on the surface of the metal oxide particles 15 ( It is characterized in that the surface modifier 12) is present in the resin 13.

The term "surface modifier" as used herein refers to a compound that is adsorbed on a solid surface to modify the surface. "Surface modification" means adsorbing a surface modifier on a solid surface.

Further, the "residue of the surface modifier" means a part of atoms in the surface modifier molecule by a reaction such as hydrolysis or acid decomposition in order to adsorb the surface modifier on a solid surface such as an inorganic filler. Alternatively, it refers to a structural portion derived from the surface modifier contained in a compound adsorbed on a solid surface among compounds (including ions and radicals) generated by dissociating an atomic group (also referred to as “group”).

As shown in FIG. 1D, the surface modifier 16 adsorbed on the surface of the metal oxide particles 15 and the surface modifier 12 present in the resin 13 have the same structure, so that the resin 13 has the same structure. Segregation of the surface modifier 12 present in the surface modifier 12 and aggregation of the surface modifier particles 14A can be suppressed, and a film can be uniformly formed. As a result, it is possible to maintain the initial high cleaning property, improve the wear resistance, and realize a photoconductor having excellent durability. Further, the presence of the surface modifier 12 having high abrasion resistance in the resin 13 suppresses image flow, improves fine line reproducibility, and can be used for a long period of time while maintaining high image quality.

Schematic diagram showing an example of the structure of a protective layer of a comparative example containing a surface modifier and a protective layer of the present invention. Schematic diagram showing the state of the fluorine-based surface modifier on the surface of metal oxide particles and in the resin Schematic diagram showing the state of the silicone-based surface modifier on the surface of the metal oxide particles and in the resin. Schematic cross-sectional view showing an example of the configuration of the electrophotographic photosensitive member of the present invention. Schematic configuration diagram showing an example of a manufacturing apparatus that can be used for preparing composite particles (core / shell particles). A photographic image obtained by photographing the convex structure due to the uplift of the metal oxide particles of the protective layer according to the present invention with a scanning electron microscope, and a binarized image of the photographic image. Schematic configuration diagram showing an example of the configuration of the electrophotographic image forming apparatus according to one embodiment of the present invention. Diagram for explaining slip-through evaluation and fine line reproducibility in Examples

The electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member having at least a protective layer containing a resin and metal oxide particles, and the metal oxide particles are surface-modified with a surface modifier. Apart from the surface modifier that modifies the surface of the metal oxide particles, the resin contains a compound having the same structural portion as the residue of the surface modifier. These features are technical features that are common to or correspond to each of the following embodiments.

In an embodiment of the present invention, from the viewpoint of exhibiting the effect of the present invention, the content of the compound having the same structural portion as the residue of the surface modifier in the resin is based on 1 part by mass of the resin. Higher image quality is maintained when it is in the range of 0.01 to 0.5 parts by mass, and further, when it is in the range of 0.02 to 0.25 parts by mass with respect to 1 part by mass of the resin. On the other hand, it is preferable in that it can exhibit excellent effects in abrasion resistance, white background contamination resistance, and fine line reproducibility.

Further, the surface of the protective layer has a plurality of convex portions, and among the plurality of convex portions, the average distance R between the convex portions (between the apex portions) of the convex portion structures adjacent to each other is 100 to 250 nm. Within the range, the convex portions become uniformly dense, and when the toner comes into contact with the surface of the photoconductor, the probability of contact with the metal oxide particles increases, and the residual toner can be reliably and quickly removed during cleaning. It is preferable in that it can be done.

Further, it is preferable that the protective layer contains a polymerized cured product of a composition containing a polymerizable monomer and metal oxide particles, because a protective layer having excellent abrasion resistance can be formed by the photoconductor.

Further, the fact that the surface modifier has an alkyl fluoride chain and that the alkyl fluoride chain has a side chain of the surface modifier allows the fluorine-containing surface modifier to be present with high adhesion. A high fluorine density can be obtained. Further, the metal oxide particles having a fluorine-containing surface modifier show good dispersibility in the protective layer coating liquid, and are preferable in that excellent dispersibility can be obtained in the coating film.

Further, the fact that the surface modifier has a silicone chain and that the silicone chain has a silicone chain on the side chain of the surface modifier efficiently hydrophobicizes the surface of the metal oxide particles, and a polymerizable monomer or an antioxidant. It is preferable in that the dispersibility is improved by increasing the compatibility with.

By subjecting the metal oxide particles to the surface modification treatment with the above-mentioned fluorine-based / silicone-based surface modifier, the adhesive force and frictional force between the metal oxide particles in the photoconductor and the toner externalizer Can be significantly reduced. As a result, the removability of residual toner can be further improved, and the generation of free external additives can be suppressed.

Further, it is preferable that the metal oxide particles have a polymerizable group because a protective layer having more excellent film strength (scratch resistance) can be formed.
In the present invention, metal oxide particles surface-treated with a surface modifier are referred to as surface-modified metal oxide particles.

Hereinafter, the present invention, its constituent elements, and modes and modes for carrying out the present invention will be described in detail. In the present application, "~" is used to mean that the numerical values described before and after the value are included as the lower limit value and the upper limit value.

《Electrophotophotograph photoconductor》
The electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member having at least a protective layer containing a resin and metal oxide particles, and the metal oxide particles are surface-modified with a surface modifier. Apart from the surface modifier that modifies the surface of the metal oxide particles, the resin contains a compound having the same structural portion as the residue of the surface modifier.

[About the same structure of the surface modifier particle surface and resin]
FIG. 2 is a schematic view showing the surface of the metal oxide particles and the state of the fluorine-based surface modifier in the resin, and shows the surface of the metal oxide particles defined in the present invention described in FIG. 1 (d). The modified fluorine-based surface modifier (a) and the compound (b) having the same structural portion as the residue of the fluorine-based surface modifier present in the resin will be described.

In FIG. 2, as the fluorine-based surface modifier 12, trimethoxy (1H, 1H, 2H, 2H-tridecafluoro-n-octyl) silane will be described as an example.

FIG. 2A shows a state in which the fluorine-based surface modifier 16 modifies the metal oxide particles 15, and in the surface modifier 16, B is a reactive group and is indicated by A. The structural range represents a residue having the same structural part as the fluorine-based surface modifier 12 existing in the resin shown in FIG. 2B.

FIG. 2B is a diagram showing the structure of the surface modifier 12 contained in the resin.

“Having the same structural portion” as used in the present invention means the residue A portion of the surface modifier 16 bonded to the metal oxide particles 15 and the substituent at the end of the surface modifier 12 present in the resin (FIG. 2). It means _{that the structural part A excluding the three} CHs (3 groups) in the above has the same structure.

In the present invention, the content of the compound having the same structural portion as the residue of the surface modifier in the resin is in the range of 0.01 to 0.5 parts by mass with respect to 1 part by mass of the resin. It is preferable that the amount is in the range of 0.02 to 0.25 parts by mass.

FIG. 3 is a schematic view showing the state of the silicone-based surface modifier on the surface of the metal oxide particles and in the resin, and is the metal oxide particles defined in the present invention described in FIG. 1 (d). The state in which the silicone-based surface modifier that modifies the surface and the state in which the resin has the same structural portion as the residue of the silicone-based surface modifier will be described.

FIG. 3 shows the structure of the silicone-based surface modifier having the structure represented by the general formula (2) described later on the surface of the metal oxide particles and in the resin, and is similar to that described in FIG. FIG. 3A shows a state in which the silicone-based surface modifier 16 modifies the metal oxide particles 15, and in the surface modifier 16, B is a reactive group and is indicated by A. Represents a residue whose structural range is the same structural part as the surface modifier 12 present in the resin.

FIG. 3B is a diagram showing the structure of the silicone-based surface modifier 12 contained in the resin.

[Basic structure of photoconductor]
First, the specific structure of the photoconductor of the present invention will be described with reference to the drawings.

FIG. 4 is a schematic cross-sectional view showing an example of the configuration of the photoconductor of the present invention.

The photoconductor of the present invention is characterized by having at least a protective layer having the constitution specified in the present invention.

FIG. 4A is a cross-sectional view showing the photoconductor 101A having the first configuration. An intermediate layer 103 is formed on the conductive support 102, a photosensitive layer 104 is provided on the intermediate layer 103, and the outermost surface thereof is provided. In the configuration in which the protective layer 105 according to the present invention is formed, the protective layer 105 contains at least a resin and metal oxide particles, and the metal oxide particles are surface-modified with a surface modifier. The surface of the oxide particles is characterized in that, apart from the surface modifier, the resin contains a compound having the same structural portion as the residue of the surface modifier.

Further, FIG. 4B is a cross-sectional view showing the photoconductor 101B having the second configuration, in which the intermediate layer 103 is formed on the conductive support 102, and the charge generation layer 106 and the electric charge are formed on the intermediate layer 103. The photosensitive layer 104 composed of the transport layer 107 is formed, and the protective layer 105 according to the present invention is formed on the outermost surface.

[Each component of the photoconductor]
[Protective layer]
The protective layer according to the present invention is a layer for protecting the photosensitive layer, which is arranged on the photosensitive layer and constitutes the surface of the photoconductor, and contains at least a resin and metal oxide particles. It is a feature.

(Metal oxide particles)
The metal oxide particles according to the present invention are not particularly limited, but refer to particles whose surface is composed of metal oxide at least.

The shape of the particles is not particularly limited, and may be any shape such as powder, spherical, rod-shaped, needle-shaped, plate-shaped, columnar, indefinite-shaped, phosphorescent-shaped, and spindle-shaped.

Examples of the metal oxide constituting the metal oxide particles are not particularly limited, but silica (silicon oxide), magnesium oxide, zinc oxide, lead oxide, alumina (aluminum oxide), tin oxide, tantalum oxide, indium oxide, and the like. Bismus oxide, yttrium oxide, cobalt oxide, copper oxide, manganese oxide, selenium oxide, iron oxide, zirconium oxide, germanium oxide, titanium dioxide, niobium oxide, molybdenum oxide, vanadium oxide and copper aluminum oxide, antimony-doped tin oxide, etc. Can be mentioned.

Among these, alumina particles, silica (SiO ₂ ) particles, tin oxide (SnO ₂ ) particles, titanium dioxide (TiO ₂ ) particles, antimony-doped tin oxide (SnO _2- Sb) particles, and copper-aluminum composite oxide (CuAlO _2). ) Particles are preferable, and silica particles and tin oxide particles are more preferable. These metal oxide particles can be used alone or in combination of two or more.

The metal oxide particles are preferably composite particles having a core-shell structure having a core material (core) and an outer shell (shell) made of metal oxide.

When such composite particles are used, the transmission of active energy rays (particularly ultraviolet rays) used for curing the protective layer is transmitted by selecting a core material having a small difference in refractive index from the polymerizable monomer. The film strength of the protective layer after curing can be improved, and the wear of the protective layer can be further reduced. Further, by controlling the selection of the material constituting the outer shell (shell) and the shape of the outer shell (shell), the surface modification effect of the surface-modified particles described later can be further enhanced. As a result, the effect of reducing wear on the photoconductor and the cleaning blade and the effect of suppressing image defects can be further improved, and the transferability to uneven paper can be further improved.

The material constituting the core material of the composite particles is not particularly limited, and examples thereof include insulating materials such as _{barium sulfate (BaSO 4} ), alumina (Al ₂ O ₃ ), and silica (SiO _2). Among these, barium sulfate and silica are preferable from the viewpoint of ensuring the light transmission of the protective layer. Further, the material constituting the outer shell (shell) of the composite particle is the same as that mentioned as the metal oxide constituting the metal oxide particle.

Preferred examples of the core-shell structure composite particles include core-shell structure composite particles having a core material made of barium sulfate and an outer shell made of tin oxide. The ratio of the average primary particle size of the number of core materials to the thickness of the outer shell is appropriately adjusted so that a desired surface modification effect can be obtained depending on the type of core material and outer shell used and the combination thereof. Just set it.

The number average primary particle size of the metal oxide particles is preferably in the range of 10 to 200 nm, and more preferably in the range of 20 to 150 nm. When the average primary particle size of the number of metal oxide particles is 10 nm or more, sufficient scratch resistance can be obtained. On the other hand, when the number average primary particle size of the metal oxide particles is 200 nm or less, the metal oxide particles do not settle in the dispersion liquid when the metal oxide particles are dispersed in the solvent when the outermost layer is formed. , The photoconductor can be stably produced.

The number average primary particle size of the metal oxide particles is defined as the number average primary particle size measured by the following method.

First, a 10000 times magnified photograph of a sample (metal oxide particles, etc.) taken by a scanning electron microscope (manufactured by JEOL Ltd.) is captured in a scanner.

Next, from the obtained photographic images, 300 metal oxide particle images excluding agglomerated metal oxide particles and particles were randomly subjected to an automatic image processing analysis system, Luzex AP Software Ver. A binarization process is performed using 1.32 (manufactured by Nireco Corporation) to calculate the horizontal ferret diameter of each of the metal oxide particle images. Then, the average value of each horizontal ferret diameter of the metal oxide particle image is calculated and used as the number average primary particle size. Here, the horizontal ferret diameter means the length of the side parallel to the x-axis of the circumscribed rectangle when the metal oxide particle image is binarized.

Further, the measurement of the number average primary particle size of the metal oxide particles shall be performed on the metal oxide particles containing no chemical species (coating layer) derived from the surface modifier. It is considered that the metal oxide particles have a thickness within an error range with respect to the metal oxide particles (generally, a thickness of about 1/10000 with respect to the metal oxide particle size) even if the surface modification treatment is applied. Therefore, it is assumed that the average primary particle size does not change by performing the surface modification treatment.

(Metal oxide particles surface-modified with a surface modifier)
The metal oxide particles surface-modified with the surface modifier according to the present invention are metal oxide particles as a raw material that have been surface-modified with a surface modifier.

The surface modification method in the present invention, that is, the method of adhering the surface modifier to the surface of the metal oxide particles, is mainly classified into two methods, a wet treatment method and a dry treatment method.

The wet treatment method is a method of adhering the surface modifier to the surface of the metal oxide particles by dispersing the metal oxide particles and the surface modifier in an appropriate solvent. As a method of dispersing in the solvent, for example, a usual dispersing means such as a ball mill or a sand mill can be used. After the dispersion treatment, the dispersion liquid is dried to remove the solvent, and then heat treatment is further performed to react and fix the surface modifier on the surface of the metal oxide particles.

In the dry treatment method, the surface modifier is attached to the surface of the metal oxide particles by mixing and kneading the surface modifier and the metal oxide particles without using a solvent. Other steps are performed in the same manner as the wet treatment described above.

(Surface modifier)
The surface modifying agent referred to in the present invention has a surface modifying functional group. As the surface-modifying functional group, it is bonded to conductive metal oxide particles such as a carboxylic acid group, a hydroxy group, -Rd-COOH (Rd is a divalent hydrocarbon group), a silyl group halide, and an alkoxysilyl group. Uru group can be mentioned. Among these, a carboxylic acid group, a hydroxy group or an alkoxysilyl group is preferable, and a hydroxy group or an alkoxysilyl group is more preferable.

<Fluorine-based surface modifier>
The fluorine-based surface modifier may be a fluorine-based surface modifier having an alkyl fluoride group in the main chain or a fluorine-based surface modifier having an alkyl fluoride group in the side chain, but the side chain type Fluorine-based surface modifiers are preferred. That is, it is preferable that the metal oxide particles are surface-modified with a side-chain type fluorine-based surface modifier.

The fluorine-based surface modifier is preferably a surface modifier having an alkoxysilyl group as the surface modification functional group, and examples thereof include compounds represented by F-1 to F-9 shown below.

Further, the fluorine-based surface modifier having an alkyl fluoride group in the side chain preferably contains a fluoroalkyl (meth) acrylate / (meth) acrylic acid copolymer structure, and the following general formula (1a) It is preferable that the compound has both the structural unit represented by and the structural unit represented by the general formula (1b).

In the above general formula (1a), R ¹ represents a hydrogen atom or a methyl group.

In the above general formula (1b), R ² represents a linear or branched-chain alkyl group having 1 to 4 carbon atoms, and X represents an alkylene group having 1 to 4 carbon atoms. R ³ represents a perfluoroalkyl group having 1 to 6 carbon atoms.

By using a fluorine-based surface modifier having both the structural unit represented by the general formula (1a) and the structural unit represented by the general formula (1b), a fluorine-based surface modifier can be applied to the surface of the metal oxide particles. It can be present with high adhesion and a high fluorine density can be obtained.

Further, since the surface-modified metal oxide particles having the fluorine-based surface modifier show good dispersibility in the protective layer coating liquid, excellent dispersibility in the coating film can be obtained.

The molecular weight of the fluorine-based surface modifier is preferably in the range of 5,000 to 30,000 in terms of number average molecular weight.

Examples of the fluorine-based surface modifier include 2,2,3,3,4,4,4-heptafluorobutyl methacrylate / acrylic acid copolymer and 2,2,3,3-tetrafluoropropyl methacrylate / methacrylic acid. Examples thereof include copolymers and 2,2,3,3,4,5,5-nonafluoropentyl methacrylate / acrylic acid copolymers, which may be used alone or in combination of two or more. Can be mixed and used.

The amount of the fluorine-based surface modifier used is preferably in the range of 0.5 to 20 parts by mass, more preferably in the range of 1 to 10 parts by mass with respect to 100 parts by mass of the unmodified metal oxide particles. Is.

It can be confirmed by differential thermal / thermogravimetric (TG / DTA) measurement that the metal oxide particles are surface-modified with a fluorine-based surface modifier.

The fluorine-based surface modifier may be a synthetic product or a commercially available product. Specific examples of commercially available products include T3560, T1770 (above, manufactured by Tokyo Chemical Industry Co., Ltd.), KY108, X-71-195 (above, manufactured by Shin-Etsu Chemical Co., Ltd.), novel2702 (manufactured by 3M), and the like. Can be done.

上記一般式（２）において、Ｒ^ａは水素原子又はメチル基を表し、ｎ′は３以上の整数を表す。 <Silicone-based surface modifier>
The silicone-based surface modifier applicable to the present invention is not particularly limited, but is preferably a compound having a structural unit represented by the following general formula (2).

In the above general formula (2), Ra ^{represents a} hydrogen atom or a methyl group, and n'represents an integer of 3 or more.

As the silicone-based surface modifier, even a silicone-based surface modifier having a silicone chain in the main chain (also referred to as a main chain type silicone-based surface modifier or a linear silicone-based surface modifier) is a side chain. A silicone-based surface modifier having a silicone chain (side-chain type silicone-based surface modifier) may be used, but a side-chain type silicone-based surface modifier is preferable. That is, it is preferable that the metal oxide particles are surface-modified with a side chain type silicone-based surface modifier.

When the surface of the metal oxide particles is modified with a side-chain type silicone-based surface modifier, the metal oxide particles are efficiently hydrophobized, and a high concentration of silicone chains is present on the surface of the metal oxide particles. Therefore, the metal oxide particles surface-modified with the side-chain type silicone-based surface modifier can be uniformly dispersed in the protective layer at a high concentration, and the particle surface is easily exposed on the surface of the photoconductor. That is, when the toner external additive comes into contact with the metal oxide particles of the photoconductor, the silicone chain is present in a high concentration, so that low friction and low adhesion can be realized. The silicone modifier also plays a role in improving the dispersibility of the metal oxide particles. By performing the surface modification treatment with a silicone-based surface modifier, the metal oxide particles are uniformly present on the surface of the photoconductor, and a dense convex structure can be formed on the surface.

The side chain type silicone-based surface modifier applicable to the present invention is not particularly limited, but preferably has a structure having a silicone chain in the side chain of the polymer main chain and further having a surface modifying functional group. .. Examples of the surface-modifying functional group include conductive metal oxide particles such as a carboxylic acid group, a hydroxy group, -Rd-COOH (Rd is a divalent hydrocarbon group), a silyl halide group, and an alkoxysilyl group. Examples include groups that can be attached. Among these, a carboxylic acid group, a hydroxy group or an alkoxysilyl group is preferable, and a hydroxy group or an alkoxysilyl group is more preferable.

The side chain type silicone-based surface modifier has a poly (meth) acrylate main chain or a silicone main chain as a polymer main chain from the viewpoint of further reducing wear of the cleaning blade while maintaining the effect of the present invention. It is preferably a structure.

The silicone chains of the side chain and the main chain preferably have a dimethylsiloxane structure as a repeating unit, and the number of repeating units thereof is preferably in the range of 3 to 100, and preferably in the range of 3 to 50. Is more preferable.

The weight average molecular weight of the silicone-based surface modifier is not particularly limited, but is preferably in the range of 1000 to 50,000. The weight average molecular weight of the silicone-based surface modifier can be measured by gel permeation chromatography (GPC).

The silicone-based surface modifier may be a synthetic product or a commercially available product. Specific examples of commercially available products of the main chain type silicone surface modifier include KF-99 and KF-9901 (all manufactured by Shin-Etsu Chemical Co., Ltd.).

Further, as a specific example of a commercially available side chain type silicone surface modifier having a silicone chain in the side chain of the poly (meth) acrylate main chain, for example, Cymac (registered trademark) US-350 (manufactured by Toagosei Co., Ltd.) ), KP-541, KP-574, KP-578 (all manufactured by Shin-Etsu Chemical Co., Ltd.) and the like.

Specific examples of commercially available side-chain type silicone-based surface modifiers having a silicone chain in the side chain of the silicone main chain include KF-9908 and KF-9909 (all manufactured by Shin-Etsu Chemical Co., Ltd.). be able to. Further, the silicone-based surface modifier can be used alone or in combination of two or more.

The method for surface-modifying the metal oxide particles with the silicone-based surface modifier is not particularly limited, and any method may be used as long as it can adsorb (bond) the silicone-based surface modifier on the surface of the metal oxide particles. Examples of such a method include a wet treatment method and a dry treatment method, and either of them may be used.

The wet treatment method is a method of adhering (or bonding) the silicone-based surface modifier on the surface of the metal oxide particles by dispersing the metal oxide particles and the silico-based surface modifier in a solvent. .. As the method, it is preferable to disperse the metal oxide particles and the silicone-based surface modifier in a solvent, dry the obtained dispersion to remove the solvent, and then further heat-treat the silicone-based surface. A method of adhering (or bonding) the silicone-based surface modifier on the surface of the metal oxide particles by reacting the modifier with the metal oxide particles is more preferable. Further, the silicone-based surface modifier and the metal oxide particles may be dispersed in a solvent, and then the obtained dispersion liquid may be wet-pulverized to make the metal oxide particles finer and at the same time proceed with the surface modification. ..

The means for dispersing the metal oxide particles and the silicone-based surface modifier in the solvent is not particularly limited, and known means can be used. Examples thereof are general dispersion means such as a homogenizer, a ball mill, and a sand mill. Can be mentioned.

As the solvent, a known solvent can be used without particular limitation, and preferred examples thereof include methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol (2-butanol), tert-butanol, and the like. Examples thereof include alcohol solvents such as benzyl alcohol, aromatic hydrocarbon solvents such as toluene and xylene, methyl ethyl ketone, and methanol. These may be used alone or in combination of two or more.

The method for removing the solvent is not particularly limited, and a known method can be used. Examples thereof include a method using an evaporator and a method for volatilizing the solvent at room temperature. Among these, a method of volatilizing the solvent at room temperature is preferable.

The heating temperature is not particularly limited, but is preferably in the range of 50 to 250 ° C, more preferably in the range of 70 to 200 ° C, and further preferably in the range of 80 to 150 ° C. .. The heating time is not particularly limited, but is preferably in the range of 1 to 600 minutes, more preferably in the range of 10 to 300 minutes, and preferably in the range of 30 to 90 minutes. More preferred. The heating method is not particularly limited, and a known method can be used.

In the dry treatment method, the silicone-based surface modifier is mixed (or bonded) on the surface of the metal oxide particles by mixing and kneading the silicone-based surface modifier and the metal oxide particles without using a solvent. It is a way to make it. In the method, the silicone-based surface modifier and the metal oxide particles are mixed and kneaded, and then heat-treated, and the silicone-based surface modifier and the metal oxide particles are reacted to cause the silicone-based surface modifier. It may be a method of adhering (or binding) the modifier on the surface of the metal oxide particles. Further, when the metal oxide particles and the silicone-based surface modifier are mixed and kneaded, they may be dry-pulverized to make the metal oxide particles finer and at the same time to proceed with the surface modification.

When the metal oxide particles surface-modified with a polymerizable surface modifier described later are surface-modified with a non-polymerizable silicone-based surface modifier, the surface modification method with the silicone-based surface modifier is a metal oxide. It suffices if the silicone surface modifier can be attached (or bonded) on the surface of the particles or on the polymerizable surface modifier.

Therefore, when a polymerizable surface modifier and a non-polymerizable surface modifier are used in combination with the metal oxide particles, the surface is first modified with the polymerizable surface modifier, and then the surface is modified with the non-polymerizable surface modifier. It is preferable to carry out.

<Method of surface modification with a surface modifier having a polymerizable group (polymerizable surface modifier)>
As described above, the metal oxide particles in the protective layer forming composition preferably have a polymerizable group. The method for introducing the polymerizable group is not particularly limited, but a method of surface modification with a polymerizable surface modifier is preferable.

The "polymerizable group of the polymerizable surface modifier" refers to a polymerizable monomer or a group having conductivity to the resin, which is a component of the resin. For example, the radically polymerizable group described later corresponds to this. Further, the "non-polymerizable modifier" means a surface modifier that does not have the polymerizable group.

That is, it is preferable that the metal oxide particles are surface-modified (polymerizable surface-modified) with a surface modifier having a polymerizable group (polymerizable surface modifier) to prepare the surface-modified metal oxide particles. The polymerizable group is supported on the surface of the metal oxide particles by the polymerizable surface modification, and as a result, the metal oxide particles have a polymerizable group. Since the metal oxide particles exist as a structure having a group derived from a polymerizable group in the protective layer, as an example of a preferable form of the present invention, the metal oxide particles are derived from a polymerizable group. It is mentioned that it has a group of.

The polymerizable surface modifier referred to in the present invention has a polymerizable group and a surface modifying functional group. The type of polymerizable group applicable in the present invention is not particularly limited, but a radically polymerizable group is preferable. Here, the radically polymerizable group represents a radically polymerizable group having a carbon-carbon double bond. Examples of the radically polymerizable group include an epoxy group, a vinyl group, a (meth) acryloyl group, and the like, and among these, a methacryloyl group is preferable.

Further, the surface-modified functional group referred to here represents a group having polymerizable property to a polar group such as a hydroxy group existing on the surface of the metal oxide particles. Examples of the surface-modified functional group include a carboxylic acid group, a hydroxy group, -Rd'-COOH (Rd' is a divalent hydrocarbon group), a silyl halide group, an alkoxysilyl group and the like. Of these, a silyl halide group and an alkoxysilyl group are preferable.

As the polymerizable surface modifier, a silane coupling agent having a radically polymerizable group is preferable, and examples of the silane coupling agent include the compounds shown in S-1 to S-32 below.

S-1: CH ₂ = CHSi (CH ₃ ) (OCH ₃ ) ₂
S-2: CH ₂ = CHSi (OCH ₃ ) ₃
S-3: CH ₂ = CHSiCl ₃
S-4: CH ₂ = CHCOO (CH ₂ ) ₂ Si (CH ₃ ) (OCH ₃ ) ₂
S-5: CH ₂ = CHCOO (CH ₂ ) ₂ Si (OCH ₃ ) ₃
S-6: CH ₂ = CHCOO (CH ₂ ) ₂ Si (OC ₂ H ₅ ) (OCH ₃ ) ₂
S-7: CH ₂ = CHCOO (CH ₂ ) ₃ Si (OCH ₃ ) ₃
S-8: CH ₂ = CHCOO (CH ₂ ) ₂ Si (CH ₃ ) Cl ₂
S-9: CH ₂ = CHCOO (CH ₂ ) ₂ SiCl ₃
S-10: CH ₂ = CHCOO (CH ₂ ) ₃ Si (CH ₃ ) Cl ₂
S-11: CH ₂ = CHCOO (CH ₂ ) ₃ SiCl ₃
S-12: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₂ Si (CH ₃ ) (OCH ₃ ) ₂
S-13: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₂ Si (OCH ₃ ) ₃
S-14: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₃ Si (CH ₃ ) (OCH ₃ ) ₂
S-15: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₃ Si (OCH ₃ ) ₃
S-16: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₂ Si (CH ₃ ) Cl ₂
S-17: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₂ SiCl ₃
S-18: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₃ Si (CH ₃ ) Cl ₂
S-19: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₃ SiCl ₃
S-20: CH ₂ = CHSi (C ₂ H ₅ ) (OCH ₃ ) ₂
S-21: CH ₂ = C (CH ₃ ) Si (OCH ₃ ) ₃
S-22: CH ₂ = C (CH ₃ ) Si (OC ₂ H ₅ ) ₃
S-23: CH ₂ = CHSi (OC ₂ H ₅ ) ₃
S-24: CH ₂ = C (CH ₃ ) Si (CH ₃ ) (OCH ₃ ) ₂
S-25: CH ₂ = CHSi (CH ₃ ) Cl ₂
S-26: CH ₂ = CHCOOSi (OCH ₃ ) ₃
S-27: CH ₂ = CHCOOSi (OC ₂ H ₅ ) ₃
S-28: CH ₂ = C (CH ₃ ) COOSi (OCH ₃ ) ₃
S-29: CH ₂ = C (CH ₃ ) COOSi (OC ₂ H ₅ ) ₃
S-30: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₃ Si (OC ₂ H ₅ ) ₃
S-31: CH ₂ = CHCOO (CH ₂ ) ₂ Si (CH ₃ ) ₂ (OCH ₃ )
S-32: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₈ Si (OCH ₃ ) ₃

The polymerizable surface modifier may be a synthetic product or a commercially available product. Specific examples of commercially available products include KBM-502, KBM-503, KBE-502, KBE-503, KBM-5103 (all manufactured by Shin-Etsu Chemical Co., Ltd.) and the like. Further, the polymerizable surface modifier can be used alone or in combination of two or more.

When both silicone surface modification and polymerizable surface modification are performed, it is preferable to perform the silicone surface modification after performing the polymerizable surface modification. By performing surface modification in this order, the wear resistance of the protective layer is further improved. The reason for this is that the oil-repellent silicone chain does not prevent the polymerizable surface modifier from coming into contact with the surface of the metal oxide particles, so that the introduction of the polymerizable group into the metal oxide particles is more efficient. Because it is done.

The method of polymerizable surface modification is not particularly limited, and a method similar to the method described for the silicone-based surface modifier can be adopted except that a polymerizable surface modifier is used. Further, a known surface modification technique for metal oxide particles may be used.

Here, when the wet treatment method is used, a solvent similar to the method described in the silicone-based surface modification can be preferably used.

The amount of the polymerizable surface modifier used is the metal oxide particles before the polymerizable surface modification (in the case of the above-mentioned metal oxide particles after the silicone surface modification, the metal oxide particles after the silicone surface modification are used. ) With respect to 100 parts by mass, it is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and further preferably 1.5 parts by mass or more. Within this range, the film strength of the protective layer is improved, and the wear of the photoconductor is further reduced. Further, 100 parts by mass of the metal oxide particles before the polymerizable surface modification (when the metal oxide particles after the silicone surface modification described above are modified with the polymerizable surface modifier, the metal oxide particles after the silicone surface modification) On the other hand, it is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, and further preferably 8 parts by mass or less. Within this range, the amount of the polymerizable surface modifier does not become excessive with respect to the number of hydroxy groups on the particle surface and becomes a more appropriate range, and the film strength of the protective layer is lowered by the unreacted polymerizable surface modifier. It is suppressed, the film strength of the protective layer is improved, and the wear of the photoconductor is further reduced.

(Preparation of surface-modified metal oxide particles)
The following shows a typical method for preparing metal oxide particles surface-modified with a surface modifier.

(1) Preparation of composite metal oxide particles (untreated):
A core-shell type composite metal oxide particle having a core formed of barium sulfate and a shell formed of tin oxide was prepared according to the following method.

Using the manufacturing apparatus shown in FIG. 5, the surface of the barium sulfate is the core particles, tin oxide to prepare a composite metal oxide fine particles Schering (Sn0 2 _/ BaSO _4).

Specifically, 3500 mL of pure water was put into the mother liquor tank 41, and then 900 g of a spherical barium sulfate core having an _{average particle size D 50 of 100 nm was put into the mother liquor tank 41 and circulated for 5 passes.}

The flow rate of the slurry flowing out of the mother liquor tank 41 was 2280 mL / min. Further, the stirring speed of the strong dispersion device 43 was set to 16000 rpm.

After the circulation is completed, the total volume of the slurry is increased to 9000 mL with pure water, 1600 g of sodium nitrate and 2.3 mL of sodium hydroxide aqueous solution (concentration 25 mol / L) are added and circulated for 5 passes to obtain a mother liquor. It was.

This mother liquor was circulated so that the flow velocity S1 flowing out of the mother liquor tank 41 was 200 mL, and 20% sulfuric acid was supplied to the homogenizer "magic LAB" (manufactured by IKA Japan Co., Ltd.) as the strong dispersion device 43. The supply rate S3 was 9.2 mL / min. The volume of the homogenizer was 20 mL, and the stirring speed was 16000 rpm. Circulation was performed for 15 minutes, during which sulfuric acid was continuously fed to the homogenizer. In this way, particles in which a tin oxide shell layer was formed on the surface of barium sulfate, which is a core particle, were obtained.

The slurry containing the obtained particles was repulp-washed until its conductivity became 600 μS / cm or less, and then Nutche filtration was performed to obtain a cake. The cake was dried in the air at 150 ° C. for 10 hours. Next, the dried cake was crushed, and the crushed powder was reduced and baked at 450 ° C. for 45 minutes _{in a 1 volume% H 2} / N _{2 atmosphere.} This gave a composite metal oxide particles having a number average primary particle diameter of 100nm tin oxide on the core particle surfaces of barium sulfate was Schering _(Sn0 2 / BaSO _4).

Here, in the manufacturing apparatus shown in FIG. 5, reference numerals 42 and 44 are provided in the circulation pipes forming a circulation path between the mother liquor tank 41 and the strong dispersion device 43, and reference numerals 45 and 46 are provided in the circulation pipes 42 and 44. Reference numeral 41a indicates a stirring blade, reference numeral 43a indicates a stirring unit, reference numerals 41b and 43b indicate a shaft, and reference numerals 41c and 43c indicate a motor.

(2) Preparation of surface-modified metal oxide particles (surface-modified metal oxide particles A: dimethyldichlorosilane treatment)
10 g of tin oxide (number average primary particle size = 20 nm) was added to 100 mL of ethanol, and the mixture was dispersed for 60 minutes using a US homogenizer. Next, 0.3 g of dimethyldichlorosilane and 10 mL of ethanol were added as a non-polymerizable coupling agent, and the mixture was dispersed for 30 minutes using a US homogenizer. After removing the solvent with an evaporator, the mixture was heated at 120 ° C. for 1 hour to obtain metal oxide particles A whose surface was modified only with non-polymerizable dimethyldichlorosilane as a surface modifier.

(Surface-modified metal oxide particles B: Mc treatment (methacrylic treatment))
100mL of ethanol above prepared composite metal oxide particles _(Sn0 2 / BaSO _4, number average primary particle diameter = 100 nm) of 10g was added, and dispersed for 60 minutes using a US Homojinaisa. Next, 0.3 g of 3-methacryloxypropyltrimethoxysilane (“KBM503” manufactured by Shinetsu Silicone Co., Ltd.) and 10 mL of ethanol were added as a coupling agent, and the mixture was dispersed for 30 minutes using a US homogenizer. After removing the solvent with an evaporator, the mixture was heated at 120 ° C. for 1 hour to obtain metal oxide particles B surface-modified with KBM503 having a polymerizable polymerizable group as a surface modifier.

(Surface-modified metal oxide particles C: Si treatment (silicone treatment))
10 g of tin oxide (number average primary particle size = 20 nm) was added to 100 mL of 2-butanol, and the mixture was dispersed for 60 minutes using a US homogenizer. Next, 0.3 g of a surface modifier having a silicone chain (“KF-9908” manufactured by Shin-Etsu Chemical Co., Ltd.) and 10 mL of 2-butanol were added to the side chain of the silicone main chain, and dispersion was performed for 60 minutes using a US homogenizer. .. After removing the solvent with an evaporator, the metal oxide particles C surface-modified with a surface modifier having a silicone chain on the side chain were obtained by heating at 120 ° C. for 1 hour.

(Surface-modified metal oxide particles D: Mc + fluorination treatment (F treatment))
First, 2,2,3,3,4,5,4-heptafluorobutylmethacrylate 9.9 g, acrylic acid 0.1 g, polymerization initiator "Perloyl SA" (manufactured by Nichiyu Co., Ltd.) 0.3 g, and a fluorine-based solvent. : Add 60.0 g of methylperfluorobutyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.) to the reaction vessel, purge with dry nitrogen to seal the reaction vessel, heat at 70 ° C. for 24 hours under stirring, and then cool the reaction vessel. , Opened. The solution in the reaction vessel is then poured into 300 mL of methanol to precipitate the resulting polymer and the precipitate is dried under vacuum to give 2,2,3,3,4,5,4-hepta. A specific fluorinated surface modifier (novec2702) made of a fluorobutyl methacrylate / acrylic acid copolymer was obtained.

100mL of ethanol to the composite metal oxide particles _(Sn0 2 / BaSO _4, number average primary particle diameter = 100 nm) of 10g was added, and dispersed for 60 minutes using a US Homojinaisa. Next, 0.3 g of 3-methacryloxypropyltrimethoxysilane (“KBM503” manufactured by Shinetsu Silicone Co., Ltd.) and 10 mL of ethanol were added as a coupling agent, and the mixture was dispersed for 30 minutes using a US homogenizer. After removing the solvent with an evaporator, the mixture was heated at 120 ° C. for 1 hour to obtain metal oxide particles having a polymerizable group.

5 g of the metal oxide particles obtained above were added to 50 mL of 2-butanol and dispersed for 60 minutes using a US homogenizer. Next, 0.15 g of the fluorinated surface modifier [A] was added, and dispersion was carried out for 60 minutes using a US homogenizer. After removing the solvent with an evaporator, the metal oxide particles D having a fluorinated surface modification and having a polymerizable group were obtained by heating at 120 ° C. for 1 hour.

(Surface-modified metal oxide particles E: Mc + silicone treatment (Si treatment))
10 g of tin oxide (number average primary particle size = 20 nm) was added to 100 mL of ethanol, and the mixture was dispersed for 60 minutes using a US homogenizer. Next, 0.3 g of 3-methacryloxypropyltrimethoxysilane (“KBM503” manufactured by Shinetsu Silicone Co., Ltd.) and 10 mL of ethanol were added as a coupling agent, and the mixture was dispersed for 30 minutes using a US homogenizer. After removing the solvent with an evaporator, the mixture was heated at 120 ° C. for 1 hour to obtain metal oxide particles having a polymerizable group.

5 g of the metal oxide particles obtained above were added to 50 mL of 2-butanol and dispersed for 60 minutes using a US homogenizer. Next, 0.15 g of a surface modifier having a silicone chain (“KF-9908” manufactured by Shin-Etsu Chemical Co., Ltd.) was added to the side chain of the silicone main chain, and dispersion was carried out for 60 minutes using a US homogenizer. After removing the solvent with an evaporator, the surface was modified by heating at 120 ° C. for 1 hour to obtain metal oxide particles E having a silicone chain on the side chain and having a polymerizable group.

For other surface-modified metal oxide particles, the surface modification having a desired composition is also performed depending on the type of untreated metal oxide particles, the types of polymerizable and non-polymerizable surface modifiers of the surface modifier, and their combinations. Metal oxide particles surface-modified with the agent can be obtained.

(Average distance R between the convex parts of the protective layer)
The protective layer according to the present invention preferably has a plurality of convex portions on the surface, and the average distance R between the convex portions adjacent to each other among the plurality of convex portions is preferably in the range of 100 to 250 nm. It is an aspect.

The surface of the protective layer according to the present invention has a convex structure due to the ridges of metal oxide particles. The "convex structure due to the uplift of the metal oxide particles" in the present invention means a convex structure formed by the exposed metal oxide particles.

The fact that the convex structure existing on the surface of the protective layer is due to the uplift of the metal oxide particles means that the photographic image of the surface of the protective layer taken with a scanning electron microscope (SEM) should be visually observed. Can be confirmed by.

The average distance R between the convex portions of the convex portion structure due to the uplift of the metal oxide particles of the protective layer (hereinafter, also referred to as “average distance R between the convex portions”) is calculated according to the following method.

First, the outermost protective layer was photographed (magnification: 10000 times, acceleration voltage: 2 kV) by a scanning electron microscope "JSM-7401F" (manufactured by JEOL Ltd.) (see (a) in FIG. 6). ), Image processing and analysis device LUZEX AP (manufactured by JEOL Ltd.) Automatic image processing and analysis system Luzex (registered trademark) AP software Ver. After importing into 1.32 (manufactured by Nireco Corporation) and binarizing the photographic image with the maximum value +30 level of the monochrome histogram as the threshold value (see (b) in FIG. 6), the distance between adjacent centers of gravity was calculated. This is defined as the average distance R between the protrusions of the convex structure due to the uplift of the metal oxide particles in the protective layer.

The average distance R between the convex portions according to the present invention is preferably in the range of 100 to 250 nm as described above. The lower limit is preferably 120 nm or more. The upper limit is preferably 240 nm or less, more preferably 225 nm or less, and even more preferably 200 nm or less.

Here, the average distance R between the protrusions of the convex structure due to the uplift of the metal oxide particles in the protective layer is the type, primary particle size and content of the metal oxide particles, the type and content of the polymerizable monomer, respectively. It can also be controlled by the presence or absence of surface modification, the type of surface modifier, the surface modification conditions, the type of untreated parent particles, and the like.

(Resin: polymerizable monomer)
The protective layer is preferably composed of a polymerized cured product of a composition containing a polymerizable metal oxide and a polymerizable monomer. As a result, the protective layer is composed of an integral polymer obtained by polymerizing the polymerizable monomer, and metal oxide particles and the like are dispersed therein. Further, the metal oxide particles and the like can be bonded to the polymer by a covalent bond by a polymerization reaction.

These polymerizable monomers and metal oxide particles may be used alone or in combination of two or more.

Hereinafter, the polymerizable monomer, which is a resin applicable to the protective layer, will be described.

The polymerizable monomer according to the present invention has a polymerizable group and is generally a photoconductor by being polymerized (cured) by irradiation with active rays such as ultraviolet rays, visible rays, and electron beams, or by addition of energy such as heating. It is a compound that becomes a resin used as a binder resin of.

The polymerizable monomer is preferably a radically polymerizable monomer that is cured through a radical polymerization reaction. Examples of the polymerizable monomer include styrene-based monomers, acrylic-based monomers, methacrylic-based monomers, vinyl toluene-based monomers, vinyl acetate-based monomers, N-vinylpyrrolidone-based monomers, and examples of the binder resin include polystyrene. Polyacrylate and the like can be mentioned.

The polymerizable group contained in the polymerizable monomer has a carbon-carbon double bond and is a polymerizable group. _{The polymerizable group is particularly preferably an acryloyl group (CH 2} = CHCO−) or a methacryloyl group (CH ₂ = C (CH ₃ ) CO−) because it can be cured with a small amount of light or in a short time. ..

上記重合性モノマーは、公知の方法で合成することができ、また市販品としても入手することができる。 Specific examples of the polymerizable monomer include, but are not limited to, the following compounds M1 to M11. In each of the following formulas, R represents an acryloyl group and R'represents a methacryloyl group.

The above-mentioned polymerizable monomer can be synthesized by a known method, and can also be obtained as a commercially available product.

Further, the polymerizable monomer is preferably a compound having three or more polymerizable groups from the viewpoint of forming a protective layer having a high crosslink density and a high hardness.

[Other components of the photoconductor]
[1. Conductive support]
The conductive support constituting the photoconductor of the present invention is not particularly limited as long as it has conductivity, and for example, a metal such as aluminum, copper, chromium, nickel, zinc, or stainless steel is molded into a drum or a sheet. A metal foil such as aluminum or copper laminated on a plastic film, aluminum, indium oxide, tin oxide, etc. deposited on a plastic film, or a conductive substance is applied alone or together with a binder resin to provide a conductive layer. Examples include metal, plastic film and paper.

[2. Middle layer]
The photoconductor of the present invention may be provided with an intermediate layer having a barrier function and an adhesive function between the conductive support and the photosensitive layer. In consideration of various failure preventions, it is preferable to provide an intermediate layer.

Such an intermediate layer contains, for example, a binder resin (hereinafter, also referred to as "binder resin for an intermediate layer") and, if necessary, conductive particles or metal oxide particles.

The binder resin for the intermediate layer is not particularly limited, and examples thereof include casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide resin, polyurethane resin, and gelatin. Of these, alcohol-soluble polyamide resins are preferred. These binder resins for the intermediate layer may be used alone or in combination of two or more.

The intermediate layer can contain various conductive particles and metal oxide particles for the purpose of adjusting resistance. For example, various metal oxide particles such as alumina, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, and bismuth oxide can be used. Further, conductive particles (ultrafine particles) such as tin-doped indium oxide, antimony-doped tin oxide and zirconium oxide can be used.

The number average primary particle size of such conductive particles or metal oxide particles is preferably 0.3 μm or less, and more preferably 0.1 μm or less.

These conductive particles or metal oxide particles may be used alone or in combination of two or more. When two or more kinds are mixed, it may take the form of a solid solution or a fusion.

The content ratio of the conductive particles or the metal oxide particles is preferably in the range of 20 to 400 parts by mass, and more preferably in the range of 50 to 350 parts by mass with respect to 100 parts by mass of the binder resin.

The layer thickness of the intermediate layer is preferably in the range of 0.1 to 15 μm, more preferably in the range of 0.3 to 10 μm.

[3. Photosensitive layer]
The photoconductor of the present invention has a photosensitive layer between the intermediate layer and the outermost layer. More specifically, the photosensitive layer is composed of a charge generating layer and a charge transporting layer.

(Charge generation layer)
The charge generation layer in the photosensitive layer constituting the photoconductor contains a charge generation substance and a binder resin (hereinafter, also referred to as “binder resin for charge generation layer”).

Examples of the charge generating substance include azo raw materials such as Sudan Red and Diane Blue, quinone pigments such as pyrenequinone and antoanthrocyanine, quinocianin pigments, perylene pigments, indigo pigments such as indigo and thioindigo, and many such as pyranthron and diphthaloylpyrene. Examples thereof include, but are not limited to, ring quinone pigments and phthalocyanine pigments. Among these, polycyclic quinone pigments and titanyl phthalocyanine pigments are preferable. These charge generating substances may be used alone or in combination of two or more.

As the binder resin for the charge generation layer, known resins can be used, for example, polystyrene resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, etc. Polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, and copolymer resin containing two or more of these resins (for example, vinyl chloride-vinyl acetate copolymer resin, chloride) Vinyl-vinyl acetate-maleic anhydride copolymer resin), poly-vinylcarbazole resin and the like, but are not limited thereto. Among these, polyvinyl butyral resin is preferable. These binder resins for the charge generation layer may be used alone or in combination of two or more.

The content ratio of the charge generating substance in the charge generating layer is preferably in the range of 1 to 600 parts by mass, more preferably in the range of 50 to 500 parts by mass with respect to 100 parts by mass of the binder resin for the charge generating layer. Is.

The layer thickness of the charge generating layer varies depending on the characteristics of the charge generating substance, the characteristics of the binder resin for the charge generating layer, the content ratio, and the like, but is preferably in the range of about 0.01 to 5 μm, more preferably 0. It is in the range of 05 to 3 μm.

(Charge transport layer)
The charge transport layer in the photosensitive layer constituting the photoconductor contains a charge transport substance and a binder resin (hereinafter, also referred to as “binder resin for charge transport layer”).

Examples of the charge-transporting substance of the charge-transporting layer include triphenylamine derivatives, hydrazone compounds, styryl compounds, benzidine compounds, and butadiene compounds.

The charge transport layer formed below the outermost layer preferably contains a charge transport material having high mobility and a large molecular weight, and a known compound can be used in combination as such a charge transport material. For example, carbazole derivative, oxazole derivative, oxaziazole derivative, thiazole derivative, thiazazole derivative, triazole derivative, imidazole derivative, imidazolone derivative, imidazolidine derivative, bisimidazolidine derivative, hydrazone compound, pyrazoline compound, oxazolone derivative, benzimidazole. Derivatives, quinazoline derivatives, benzofuran derivatives, aclysine derivatives, phenazine derivatives, aminostilben derivatives, triarylamine derivatives, phenylenediamine derivatives, stillben derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, etc. Can be mentioned. These compounds can be used alone or in combination of two or more.

A known resin can be used as the binder resin for the charge transport layer, and a polycarbonate resin, a polyacrylate resin, a polyester resin, a polystyrene resin, a styrene-acrylic nitrile copolymer resin, a polymethacrylic acid ester resin, and a styrene-methacrylic acid ester can be used. Examples thereof include a copolymer resin, but a polycarbonate resin is preferable. Further, BPA (bisphenol A) type, BPZ (bisphenol Z) type, dimethyl BPA type, BPA-dimethyl BPA copolymer type polycarbonate resin and the like are preferable in terms of crack resistance, abrasion resistance and charging characteristics. These binder resins for the charge transport layer may be used alone or in combination of two or more.

The content ratio of the charge transporting substance in the charge transport layer is preferably in the range of 10 to 500 parts by mass, more preferably in the range of 20 to 250 parts by mass with respect to 100 parts by mass of the binder resin for the charge transport layer. Is.

The layer thickness of the charge transport layer varies depending on the characteristics of the charge transport material, the characteristics of the binder resin for the charge transport layer, the content ratio, and the like, but is preferably in the range of 5 to 40 μm, more preferably in the range of 10 to 30 μm. Inside.

Antioxidants, electron conductive agents, stabilizers, silicone oils and the like may be added to the charge transport layer. It is preferable that the antioxidant is disclosed in JP-A-2000-305291, and the electronic conductive agent is disclosed in JP-A-50-137543, JP-A-58-76483, and the like.

[Manufacturing method of photoconductor]
The method for producing the photoconductor of the present invention includes a step of forming an uncured film containing a polymerizable compound on a photosensitive layer on a conductive support and a step of irradiating the uncured film with light to obtain a cured resin. It is preferably produced by a production method having the following steps, which is further provided with a step of forming the outermost layer to be contained, and is not particularly limited.

Step (1): A step of forming an intermediate layer by applying a coating liquid for forming an intermediate layer to the outer peripheral surface of the conductive support and drying the coating liquid.
Step (2): A coating liquid for forming a charge generating layer is applied to the outer peripheral surface of the conductive support or the outer peripheral surface of the intermediate layer formed on the conductive support by the step (1) and dried. By forming a charge generation layer,
Step (3): A charge transport layer is formed by applying a coating liquid for forming a charge transport layer to the outer peripheral surface of the conductive support or the outer peripheral surface of the charge generation layer formed on the intermediate layer and drying the coating liquid. Process,
Step (4): A step of forming the outermost layer by applying a coating liquid for forming the outermost layer to the outer peripheral surface of the charge transport layer formed on the charge generating layer, polymerizing, and curing the coating liquid.

The concentration of each component in the coating liquid for forming each layer is appropriately selected according to the layer thickness and production rate of each layer.

In the coating liquid for forming each layer, an ultrasonic disperser, a ball mill, a sand mill, a homomixer, or the like can be used as a means for dispersing particles such as conductive particles and metal oxide particles and a charge generating substance. However, it is not limited to these.

The method of applying the coating liquid for forming each layer is not particularly limited, and is, for example, a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a blade coating method, a beam coating method, a slide hopper method, or a circular shape. Known methods such as the slide hopper method can be mentioned.

The method for drying the coating film can be appropriately selected depending on the type of solvent and the layer thickness, but heat drying or natural drying is preferable.

Hereinafter, the details of the forming process of each layer will be described.

<Step (1): Formation of intermediate layer>
For the intermediate layer, a binder resin for the intermediate layer is dissolved in a solvent to prepare a coating liquid for forming the intermediate layer, and if necessary, other components such as conductive particles, metal oxide particles, a dispersant and a leveling agent are prepared. Is dispersed or dissolved, the coating liquid is applied onto the conductive support to a certain layer thickness to form a coating film, and the coating film is dried to form the coating film.

The coating liquid for forming the intermediate layer is preferably applied by using a dip coating method.

As the solvent used in the intermediate layer forming step, a solvent in which conductive particles and metal oxide particles are well dispersed and a binder resin for the intermediate layer, particularly a polyamide resin, is dissolved is preferable. Specifically, alcohols having 1 to 4 carbon atoms such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, tert-butanol, and sec-butanol (2-butanol) are soluble in the polyamide resin. It has excellent coating performance and is preferable. In addition, benzyl alcohol, toluene, dichloromethane, cyclohexanone, tetrahydrofuran and the like can be mentioned as co-solvents that can be used in combination with the above-mentioned solvents to obtain preferable effects in order to improve storage stability and particle dispersibility.

<Step (2): Formation of charge generation layer>
In the charge generation layer, a charge generation substance is dispersed in a solution in which a binder resin for the charge generation layer is dissolved in a solvent to prepare a coating liquid for forming a charge generation layer, and the coating liquid is constant on the intermediate layer. It can be formed by applying to the layer thickness of (1) to form a coating film and drying the coating film.

The coating liquid for forming the charge generation layer is preferably applied by using a dip coating method.

Examples of the solvent used for forming the charge generation layer include toluene, xylene, dichloromethane, 1,2-dichloroethane, methyl ethyl ketone, cyclohexane, ethyl acetate, tert-butyl acetate, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, and the like. n-butanol, tert-butanol, sec-butanol (2-butanol), methyl cellosolve, 4-methoxy-4-methyl-2-pentanone, ethyl cellosolve, methanol, 1-dioxane, 1,3-dioxolane, pyridine, diethylamine However, it is not limited to these.

<Step (3): Formation of charge transport layer>
For the charge transport layer, a coating liquid for forming a charge transport layer in which a binder resin for the charge transport layer and a charge transport substance are dissolved in a solvent is prepared, and the coating liquid is applied on the charge generation layer to a certain layer thickness. It can be formed by forming a coating film and drying the coating film.

The coating liquid for forming the charge transport layer is preferably applied by using a dip coating method.

Examples of the solvent used for forming the charge transport layer include toluene, xylene, dichloromethane, 1,2-dichloroethane, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-. Butanol, tert-butanol, sec-butanol (2-butanol), tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, pyridine, diethylamine and the like can be mentioned, but are not limited thereto.

<Step (4): Formation of protective layer>
The protective layer is known to contain a polymerizable monomer forming a resin, surface-modified metal oxide particles, and, if necessary, other components such as a polymerization initiator, a specific radical scavenger, a lubricant, and a charge-transporting substance. The coating solution for forming the outermost layer is prepared by adding to a solvent, and the coating solution for forming the protective layer is applied to the outer peripheral surface of the charge transport layer formed in the step (3) to form a coating film, and this coating solution is formed. A protective layer can be formed by drying the film and irradiating it with active rays such as ultraviolet rays or electron beams to polymerize the polymerizable compound component in the coating film and then curing the film.

The coating liquid for forming the protective layer is preferably applied by the slide hopper method using a circular slide hopper coating device, and can be applied by a method disclosed in, for example, Japanese Patent Application Laid-Open No. 2015-114454.

As the solvent used for forming the protective layer, any solvent can be used as long as a polymerizable compound, metal oxide particles and the like can be dissolved or dispersed. For example, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n. -Butanol, tert-butanol, sec-butanol (2-butanol), benzyl alcohol, toluene, xylene, dichloromethane, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3 − Dioxolane, pyridine, diethylamine and the like, but are not limited thereto.

The method for reacting the polymerizable compound is not particularly limited, and examples thereof include a method of reacting by electron beam cleavage, a method of adding a radical polymerization initiator, and a method of reacting with light and heat.

The cured resin component is produced by irradiating the coating film with active rays as a curing treatment, generating radicals to polymerize, and forming cross-linking bonds between and within the molecules by a cross-linking reaction to cure. As the active ray, ultraviolet rays and electron beams are more preferable, and ultraviolet rays are particularly preferable because they are easy to use.

<< Electrophotograph image formation method >>
The electrophotographic image forming method according to the present invention is at least
1) The charging process for charging the surface of the electrophotographic photosensitive member and
2) An exposure step of forming an electrostatic latent image by exposing the surface of the electrophotographic photosensitive member.
3) A developing process in which the electrostatic latent image is visualized with toner to form a toner image, and
4) A transfer step of transferring the toner image to a transfer medium,
It is preferable that the electrophotographic photosensitive member used in 1) to 4) is the electrophotographic photosensitive member of the present invention.

In addition, if necessary, 5) a cleaning process to remove residual toner, and
6) The static elimination process to remove the residual charge,
You may have.

The photoconductor of the present invention can be used in various known electrophotographic image forming methods. For example, it can be used in a monochrome image forming method or a full-color image forming method. In the full-color image forming method, a four-cycle image forming method composed of four types of color developing devices for each of yellow, magenta, cyan, and black and one photoconductor, and color developing for each color. Any image forming method can be used, such as a tandem image forming method in which an image forming unit having an apparatus and a photoconductor is mounted for each color.

Specifically, as the method for forming an electrophotographic image according to the present invention, the photoconductor of the present invention is used, and the photoconductor is charged (charging step) by a charging device and image-exposed (exposure step). The electrostatic latent image formed by the above is developed (developing step) using a developing device to visualize it to obtain a toner image. This toner image is transferred (transfer step) onto a transfer medium such as copy paper or a transfer belt, and then a static elimination step is performed, and then the next image formation cycle is performed. The toner image transferred on a transfer medium such as a transfer belt is transferred onto the copy paper, and the toner image transferred on the copy paper is fixed (fixed step) on the copy paper by a fixing process such as a contact heating method. To obtain a visible image. After the transfer step, the toner remaining on the photoconductor (transfer residual toner) is removed (cleaning step) by a rubber blade or the like. This cleaning step may be before or after the static elimination step, but when the static elimination step is static elimination by light irradiation, the toner remaining on the photoconductor absorbs the static elimination light after the cleaning step. It is preferable because it does not interfere with it and can effectively eliminate static electricity.

In the static elimination process, either AC static elimination (AC static elimination) or optical static elimination may be used, but AC static elimination requires the installation of an AC power supply, which causes problems such as space problems or large-scale equipment. Static elimination is preferable.

《Electrophotograph image forming device》
Next, a specific electrophotographic image forming method will be described using an electrophotographic image forming apparatus.

The electrophotographic image forming apparatus of the present invention uses the photoconductor of the present invention to be charged by a charging device on the photoconductor, and an exposure means for forming an electrostatic latent image formed by image exposure. It also has a developing means for obtaining a toner image by visualizing it by developing it with a developing device, a transfer means for transferring the toner image onto a transfer medium such as paper or a transfer belt, and a static elimination means. The toner image directly transferred onto the copy paper and the toner image transferred onto the paper via a transfer medium such as a transfer belt obtain a visible image by a fixing means fixed to the copy paper by a fixing process such as a contact heating method. After the transfer, the toner remaining on the photoconductor (transfer residual toner) is removed by a cleaning means such as a cleaning blade.

FIG. 7 is a schematic cross-sectional view showing the structure of a tandem type electrophotographic image forming apparatus including the electrophotographic photosensitive member of the present invention.

The image forming apparatus 100 shown in FIG. 7 is referred to as a tandem type color image forming apparatus, and is supplied with four sets of image forming units (image forming units) 10Y, 10M, 10C, 10Bk, an intermediate transfer body unit 7. It is composed of a paper means 21 and a fixing means 24. A document image reading device SC is arranged above the main body A of the electrophotographic image forming device.

The four image forming units 10Y, 10M, 10C, and 10Bk rotate around the photoconductors 1Y, 1M, 1C, and 1Bk with the charging means 2Y, 2M, 2C, and 2Bk, and the exposure means 3Y, 3M, 3C, and 3Bk. From the developing means 4Y, 4M, 4C, 4Bk, the primary transfer rollers 5Y, 5M, 5C, 5Bk as the primary transfer means, and the cleaning means 6Y, 6M, 6C, 6Bk for cleaning the photoconductors 1Y, 1M, 1C, 1Bk. It is configured.

In the electrophotographic image forming apparatus of the present invention, the photoconductors of the present invention described above are used as the photoconductors 1Y, 1M, 1C, and 1Bk, respectively.

The image forming units 10Y, 10M, 10C, and 10Bk have the same configuration except that the toner colors provided are different, such as yellow (Y) color, magenta (M) color, cyan (C) color, and black (Bk) color, respectively. Is. Therefore, in the following, the image forming unit 10Y will be described in detail as an example.

The image forming unit 10Y has a charging means 2Y, an exposure means 3Y, a developing means 4Y, and a cleaning means 6Y around the photoconductor 1Y which is an image forming body, and a yellow (Y) toner image is formed on the photoconductor 1Y. It is what forms.

The charging means 2Y is a means for uniformly charging the surface of the photoconductor 1Y to a negative electrode property. As the charging means 2Y, for example, a corona discharge type charger is used.

The exposure means 3Y is a means for forming an electrostatic latent image corresponding to a yellow image by exposing the photoconductor 1Y to which a uniform potential is applied by the charging means 2Y based on an image signal (yellow). is there. As the exposure means 3Y, one composed of LEDs and imaging elements in which light emitting elements are arranged in an array in the axial direction of the photoconductor 1Y, a laser optical system, or the like is used.

The developing means 4Y is, for example, a voltage applying device that applies a DC and / or AC bias voltage between a developing sleeve (not shown) and a photoconductor that has a built-in magnet and holds a developer and rotates, and the developing sleeve. It consists of.

The developing means 4Y comprises, for example, a developing sleeve having a built-in magnet and holding a developer and rotating, and a voltage applying device for applying a DC and / or AC bias voltage between the developing sleeve and the photoconductor. ..

The fixing means 24 is, for example, a heat roller fixing composed of a heating roller provided with a heating source inside and a pressure roller provided in a state of being pressure-contacted so as to form a fixing nip portion on the heating roller. There is a method.

The cleaning means 6Y is composed of a cleaning blade. A brush roller may be provided on the upstream side of the cleaning blade.

Further, a lubricant supply means (not shown) for supplying (applying) the lubricant to the surface of the photoconductor 1Y may be provided. The lubricant supply means can be provided, for example, on the downstream side of the primary transfer roller 5Y and on the upstream side of the cleaning means 6Y. However, it may be on the downstream side of the cleaning means 6Y.

The image forming apparatus 100 is configured by integrally coupling a photoconductor and components such as a developing means and a cleaning means as a process cartridge (image forming unit), and the image forming unit can be detachably attached to and detached from the apparatus main body. It may be configured. Further, at least one of a charging means, an exposure means, a developing means, a transfer means, and a cleaning means is integrally supported together with a photoconductor to form a process cartridge (image forming unit), and a single image can be detachably attached to the main body of the apparatus. The unit may be detachable by using a guide means such as a rail of the main body of the device.

The endless belt-shaped intermediate transfer unit 7 has an endless belt-shaped intermediate transfer body 70 as a semi-conductive endless belt-shaped second image carrier that is wound by a plurality of rollers and rotatably supported.

Images of each color formed by the image forming units 10Y, 10M, 10C and 10Bk are sequentially transferred onto the rotating endless belt-shaped intermediate transfer body 70 by the primary transfer rollers 5Y, 5M, 5C and 5Bk as the primary transfer means. To form a composite color image. The transfer material (image support carrying the fixed final image: for example, plain paper, transparent sheet, etc.) P housed in the paper feed cassette 20 is fed by the paper feed means 21, and the plurality of intermediate rollers 22A, It is conveyed to the secondary transfer roller 5b as the secondary transfer means via the 22B, 22C, 22D, and the resist roller 23, and is secondarily transferred onto the transfer material P to collectively transfer the color image. The transfer material P to which the color image is transferred is fixed by the fixing means 24, sandwiched between the paper ejection rollers 25, and placed on the paper ejection tray 26 outside the machine. Here, the transfer support of the toner image formed on the photoconductor such as the intermediate transfer body or the transfer material is generically referred to as a transfer medium.

On the other hand, after the color image is transferred to the transfer material P by the secondary transfer roller 5b as the secondary transfer means, the residual toner is removed from the endless belt-shaped intermediate transfer body 70 by which the transfer material P is curvature-separated by the cleaning means 6b. Toner.

During the image forming process, the primary transfer roller 5Bk is always in contact with the photoconductor 1Bk. The other primary transfer rollers 5Y, 5M and 5C abut on the corresponding photoconductors 1Y, 1M and 1C only during color image formation.

The secondary transfer roller 5b comes into contact with the endless belt-shaped intermediate transfer body 70 only when the transfer material P passes through the transfer material P and the secondary transfer is performed.

Further, the housing 8 can be pulled out from the main body of the device via the support rails 82L and 82R.

The housing 8 includes image forming portions 10Y, 10M, 10C and 10Bk, and an endless belt-shaped intermediate transfer unit 7.

The image forming portions 10Y, 10M, 10C and 10Bk are vertically arranged in columns. An endless belt-shaped intermediate transfer unit 7 is arranged on the left side of the photoconductors 1Y, 1M, 1C and 1Bk in the drawing. The endless belt-shaped intermediate transfer unit 7 includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rollers 71, 72, 73, and 74, a primary transfer roller 5Y, 5M, 5C, and 5Bk, and a cleaning means 6b. Consists of.

Although the charging roller method is shown as an example of the charging method in FIG. 7, the scorotron charging method can also be applied to the electrophotographic image forming apparatus of the present invention.

<< Toner and developer >>
In the present invention, the "toner matrix particle" constitutes the matrix of the "toner particle". The "toner matrix particles" include at least a binder resin and a colorant, and may also contain other constituent components such as a release agent (wax) and a charge control agent, if necessary. "Toner matrix particles" are referred to as "toner particles" due to the addition of an external additive. The "toner" refers to an aggregate of "toner particles".

In the present invention, the toner applied to the image forming apparatus is not particularly limited, and various known toners can be used.

As the toner, either a pulverized toner or a polymerized toner can be used, but it is preferable to use a polymerized toner from the viewpoint of obtaining a high-quality image.

The average particle size of the toner is not particularly limited, but is preferably in the range of 2 to 8 μm in terms of volume-based median diameter. By setting this range, the resolution can be further increased.

Further, an appropriate amount of inorganic particles such as silica and titania having an average particle size of about 10 to 300 nm, an abrasive having an average particle size of about 0.2 to 3 μm, etc. are externally added to the toner base particles as an external additive. be able to.

When the toner is used as a two-component developer, the carrier is a conventionally known material such as a ferromagnetic metal such as iron, an alloy of the ferromagnetic metal with aluminum and lead, and a compound of the ferromagnetic metal such as ferrite and magnetite. Magnetic particles made of the above can be used. Of these, ferrite is particularly preferable.

As the carrier, it is preferable to use a carrier further coated with a resin or a so-called resin-dispersed carrier in which magnetic particles are dispersed in the resin. The resin composition for coating is not particularly limited, but for example, it is preferable to use a cyclohexyl methacrylate-methyl methacrylate copolymer or the like.

The median diameter based on the volume of the carrier is preferably in the range of 15 to 100 μm, and more preferably in the range of 25 to 60 μm.

The concentration of the toner contained in the two-component developer is preferably in the range of 4.0 to 8.0% by mass.

Although the embodiments of the present invention have been specifically described above, the embodiments of the present invention are not limited to the above examples, and various modifications can be made.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto. In the examples, the indication of "parts" or "%" is used, but unless otherwise specified, it indicates "parts by mass" or "% by mass". Unless otherwise specified, each operation was performed at room temperature (25 ° C.).

<< Preparation of surface-modified metal oxide particles >>
[Preparation of surface-modified metal oxide particles 1]
According to the "preparation method of metal oxide particles A (dimethyldichlorosilane treatment)" described in the section "Preparation of surface-modified metal oxide particles", dimethyldi is applied to the surface _{of SiO 2 particles having a number average primary particle size of 20 nm.} Metal oxide particles 1 surface-modified with chlorosilane were prepared.

[Preparation of surface-modified metal oxide particles 2]
According to the "Method for preparing metal oxide particles C" described in the section "Preparation of surface-modified metal oxide particles", the _{surface of SnO 2} particles having a number average primary particle size of 20 nm is surface-modified with KF9908. 2 was prepared.

[Preparation of surface-modified metal oxide particles 3]
(Preparation of composite metal oxide particles (untreated))
According to the method for preparing composite metal oxide particles (untreated) described in the section "Preparation of surface-modified metal oxide particles", the number average primary particle size of barium sulfate core particles in which tin oxide is shelled is determined. 100nm of composite metal oxide particles _(Sn0 2 / BaSO ₄₎ was prepared.

(Surface modification treatment)
Then, 100mL of ethanol to the composite metal oxide particles _(Sn0 2 / BaSO ₄₎ 10g was added and dispersed for 60 minutes using a US Homojinaisa. Next, 0.3 g of 3-methacryloxypropyltrimethoxysilane (“KBM503” manufactured by Shinetsu Silicone Co., Ltd.) and 10 mL of ethanol were added as a coupling agent, and the mixture was dispersed for 30 minutes using a US homogenizer. After removing the solvent with an evaporator, the mixture was heated at 120 ° C. for 1 hour to obtain metal oxide particles having a polymerizable group.

5 g of the metal oxide particles obtained above were added to 50 mL of 2-butanol and dispersed for 60 minutes using a US homogenizer. Next, 0.15 g of a surface modifier having a silicone chain (“KF-9908” manufactured by Shin-Etsu Chemical Co., Ltd.) was added to the side chain of the silicone main chain, and dispersion was carried out for 60 minutes using a US homogenizer. After removing the solvent with an evaporator, the metal oxide particles 3 having a silicone chain on the side chain and having a polymerizable group were obtained by heating at 120 ° C. for 1 hour.

[Preparation of surface-modified metal oxide particles 4]
In the preparation of the metal oxide particles 3 described above surface-modified, as the metal oxide particles, except that in place of the composite metal oxide particles _(Sn0 2 / BaSO _4), number average primary particle diameter using a SnO ₂ particles 20nm Obtained surface-modified metal oxide particles 4 in the same manner.

[Preparation of surface-modified metal oxide particles 5]
In the preparation of the metal oxide particles 2 described above surface modification, except that the metal oxide particles, instead of the SnO ₂ particles having a number average primary particle diameter of 20 nm, was used composite metal oxide particles _(Sn0 2 / BaSO ₄₎ Obtained surface-modified metal oxide particles 5 in the same manner.

[Preparation of surface-modified metal oxide particles 6 to 12]
In the preparation of the surface-modified metal oxide particles 3, the surface-modified metal oxide was prepared in the same manner except that the type of the non-polymerizable surface modifier for surface modification was changed to the compounds shown in Table I. Particles 6-12 were prepared.

[Preparation of surface-modified metal oxide particles 13]
In the preparation of the surface-modified metal oxide particles 4, the non-polymerizable surface modifier KF9908 (manufactured by Shin-Etsu Chemical Co., Ltd.) for surface modification was used as 2,2,3,3,4,5,4-heptafluorobutyl. Surface-modified metal oxide particles 13 were prepared in the same manner except that they were changed to a specific fluorinated surface modifier (novec2702) composed of a methacrylate / acrylic acid copolymer.

(Surface modifier)
Details of each surface modifier used for preparing each of the surface-modified metal oxide particles are as follows.

・ＫＦ９９０８：シリコーン主鎖の側鎖に、シリコーン鎖を有する分岐型シリコーン（信越化学工業社製）
〈重合性表面修飾剤〉
・ＫＢＭ５０３：３−メタクリロキシプロピルトリメトキシシラン（信越化学工業社製） <Non-polymerizable surface modifier>
-Dimethyldichlorosilane-T3560: Fluoroalkylsilane (manufactured by Tokyo Chemical Industry Co., Ltd.)
-KY-108: Alkoxysilane having a perfluoropolyether chain (manufactured by Shin-Etsu Chemical Co., Ltd.)
Novec2702: 2,2,3,3,4,4-heptafluorobutyl methacrylate / acrylic acid copolymer (manufactured by 3M)
・ Octylsilane ・ KF99: Linear silicone (methylhydrogen silicone oil, manufactured by Shin-Etsu Chemical Co., Ltd.)
-KF9901: Linear methyl hydrogen silicone oil represented by the following structure (manufactured by Shin-Etsu Chemical Co., Ltd.)

-KF9908: Branched silicone having a silicone chain on the side chain of the silicone main chain (manufactured by Shin-Etsu Chemical Co., Ltd.)
<Polymerizable surface modifier>
KBM503: 3-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.)

<< Preparation of photoconductor >>
[Preparation of Photoreceptor 1]
(Preparation of conductive support)
The surface of the cylindrical aluminum support was machined to prepare a conductive support.

(Formation of intermediate layer)
The following components were mixed in the following composition ratios and dispersed in a batch system for 10 hours using a sand mill as a disperser to prepare a coating liquid for forming an intermediate layer. The prepared coating liquid for forming an intermediate layer was dip-coated on the surface of the conductive support by a dipping coating method and dried at 110 ° C. for 20 minutes to form an intermediate layer having a film thickness of 2 μm on the conductive support. ..

<Preparation of coating liquid for intermediate layer formation>
Polyamide resin (X1010 manufactured by Daicel Degusa) 10 parts by mass Titanium oxide particles (SMT500SAS manufactured by TAYCA) 11 parts by mass Ethanol 200 parts by mass

(Formation of charge generation layer)
By mixing the following components in the following composition ratio and dispersing a circulating ultrasonic homogenizer (RUS-600TCVP; manufactured by Nissei Tokyo Office Co., Ltd.) at 19.5 kHz and 600 W at a circulating flow rate of 40 L / hour for 0.5 hours. , A coating liquid for forming a charge generation layer was prepared. The prepared coating liquid for forming a charge generating layer was applied to the surface of the intermediate layer by a dip coating method and dried to form a charge generating layer having a film thickness of 0.3 μm on the intermediate layer. The charge generating substances are titanyl phthalocyanine and (2R, 3R) having clear peaks at 8.3 °, 24.7 °, 25.1 °, and 26.5 ° in Cu-Kα characteristic X-ray diffraction spectrum measurement. A mixed crystal of a 1: 1 adduct of -2,3-butanediol and unadded titanyl phthalocyanine was used.

<Coating liquid for forming a charge generation layer>
Charge generator 24 parts by mass Polyvinyl butyral resin (Eslek BL-1, manufactured by Sekisui Chemical Co., Ltd.) 12 parts by mass Mixed solution (3-methyl-2-butanone / cyclohexanone = 4/1 (volume ratio))
400 parts by mass (formation of charge transport layer)
A charge transport layer forming coating solution prepared by mixing the following components in the following composition ratio is applied to the surface of the charge generation layer by an immersion coating method, and dried at 120 ° C. for 70 minutes to obtain a charge having a film thickness of 24 μm. A transport layer was formed on the charge generation layer.

<Coating liquid for forming a charge transport layer>
Charge transport material represented by the following structural formula 60 parts by mass Polycarbonate resin (Z300, manufactured by Mitsubishi Gas Chemical Company) 100 parts by mass Antioxidant (IRGANOX1010, manufactured by BASF) 4 parts by mass

(Formation of protective layer)
The following components were mixed in the following composition ratios, and the coating liquid 1 for forming a protective layer prepared by dispersing and dissolving was applied to the surface of the charge transport layer using a circular slide hopper coating machine. Next, the product was dried at 110 ° C. for 70 minutes to form a thermoplastic protective layer having a dry film thickness of 6.0 μm to prepare a photoconductor 1. The content of dimethyldichlorosilane in the protective layer with respect to 1 part by mass of the resin is 0.1 part by mass.

<Preparation of coating liquid 1 for forming a protective layer>
Surface-modified metal oxide particles 1 (Silica particles having a number average primary particle size of 20 nm surface-modified with dimethyldichlorosilane) 120 parts by mass Charge transport material: (N- (4-methylphenyl) -N- {4- ( β-phenylstyryl) phenyl} -p-toluidine) 150 parts by mass Polycarbonate resin (Z300: manufactured by Mitsubishi Gas Chemicals) 300 parts by mass Antioxidant (IRGANOX1010 :: manufactured by BASF Japan) 12 parts by mass tetrahydrofuran (THF) 2800 parts by mass Part Silicone oil (KF-54: manufactured by Shin-Etsu Chemical Co., Ltd.) 4 parts by mass Dimethyldichlorosilane 30 parts by mass

[Preparation of Photoreceptor 2]
In the preparation of the photoconductor 1, the charge transport layer was formed in the same manner, and the protective layer was formed according to the following method to prepare the photoconductor 2.

(Formation of protective layer)
The following components were mixed in the following composition ratio, and the protective layer forming coating liquid 2 (radical polymerizable resin composition) was applied to the surface of the charge transport layer using a circular slide hopper coating machine. Next, the formed coating film was irradiated with ultraviolet rays for 1 minute with a metal halide lamp to cure the coating film, thereby forming a protective layer having a film thickness of 3.0 μm on the charge transport layer.

<Preparation of coating liquid 2 for forming protective layer>
Radical Polymerizable Monomer (Example Compound M2) 120 parts by mass Surface-modified metal oxide particles 2 (Tin oxide having a number average primary particle size of 20 nm surface-modified with KF9908) 100 parts by mass Polymerization initiator (Irgacure 819, BASF Japan, Inc.) (Manufactured by) 10 parts by mass 2-butanol 400 parts by mass KF9908 (above, manufactured by Shinetsu Chemical Co., Ltd.) 12 parts by mass

[Preparation of Photoreceptor 3]
In the preparation of the photoconductor 2, the photoconductor 3 was prepared in the same manner except that the protective layer was formed according to the following method.

(Formation of protective layer)
The following components were mixed in the following composition ratio, and the protective layer forming coating liquid 3 (radical polymerizable resin composition) was applied to the surface of the charge transport layer using a circular slide hopper coating machine. Next, the formed coating film was irradiated with ultraviolet rays for 1 minute with a metal halide lamp to cure the coating film, thereby forming a protective layer having a film thickness of 3.0 μm on the charge transport layer. The content of KF9908 in the protective layer with respect to 1 part by mass of the resin is 0.005 part by mass.

<Preparation of coating liquid 3 for forming protective layer>
Radical polymerizable monomer (Example compound M2) 120 parts by mass Surface-modified metal oxide particles 3 (KBM503 as a polymerizable surface modifier and KF9908 as a non-polymerizable surface modifier) A composite having a number average primary particle size of 100 nm metal oxide particles _{(Sn0 2 / BaSO 4))} 100 parts by weight polymerization initiator (IRGACURE 819, BASF Japan Ltd.) output 10 parts by mass of 2-butanol 400 parts by KF9908 (front, manufactured by Shin-Etsu chemical Co., Ltd.) 0.6 wt Department

[Preparation of Photoreceptors 4 to 24]
In the production of the photoconductor 3, the conditions for forming the protective layer are other than changing the types of surface-modified metal oxide particles shown in Table I, and the types and amounts of surface modifiers added in the coating liquid for forming the protective layer. Made photoconductors 4 to 24 in the same manner.

In the photoconductors 13, 15 and 16, the amount of the surface-modified metal oxide particles 3 added to the photoconductor 14 at the time of forming the protective layer was appropriately adjusted, and the average distance between the convex portions was adjusted from 180 nm. It was changed to 100 nm, 250 nm, and 280 nm.

[Preparation of Photoreceptor 25]
In the preparation of the photoconductor 1, the charge transport layer was formed in the same manner, and the protective layer was formed according to the following method to prepare the photoconductor 25.

(Formation of protective layer)
The coating liquid 20 for forming a protective layer prepared by mixing the following components in the following composition ratios, dispersing and dissolving them was applied to the surface of the charge transport layer using a circular slide hopper coating machine. Next, the product was dried at 110 ° C. for 70 minutes to form a thermoplastic protective layer having a dry film thickness of 6.0 μm to prepare a photoconductor 25. The content of novec2702 in the protective layer with respect to 1 part by mass of the resin is 0.1 part by mass.

<Preparation of coating liquid 25 for forming a protective layer>
Charge transport material: (N- (4-methylphenyl) -N- {4- (β-phenylstyryl) phenyl} -p-toluidine) 150 parts by mass Polycarbonate resin (Z300: manufactured by Mitsubishi Gas Chemical Company) 300 parts by mass Oxidation Inhibitor (IRGANOX1010, manufactured by BASF Japan) 12 parts by mass tetrahydrofuran (THF) 2800 parts by mass Silicone oil (KF-54: manufactured by Shin-Etsu Chemical Co., Ltd.) 4 parts by mass novec2702 (mentioned above, manufactured by 3M) 30 parts by mass

[Preparation of Photoreceptor 26]
In the preparation of the photoconductor 12, the charge transport layer is formed in the same manner, and as a coating liquid for forming a protective layer, as a surface modifier to be added to the surface-modified metal oxide particles, novel 2702 (instead of KF9908) ( The photoconductor 26 was produced in the same manner as described above, except that KF9908 (described above, manufactured by Shin-Etsu Chemical Co., Ltd.), which is a surface modifier contained in the resin, was removed.

[Preparation of Photoreceptor 27]
In the preparation of the photoconductor 14, the charge transport layer is formed in the same manner, and as the coating liquid for forming the protective layer, novec2702 (above, above,) is used instead of the surface modifier KF9908, which is a surface modifier contained in the resin. Photoreceptor 27 was produced in the same manner except that 3M) was used.

[Measurement of average distance between protrusions on the surface of the protective layer]
The surface of the protective layer of each of the prepared photoconductors was observed by the following method, and the average distance between the convex portions was measured.

The protective layer is image-processed from a photographic image (see (a) in FIG. 6) taken by a scanning electron microscope "JSM-7401F" (manufactured by JEOL Ltd.) (magnification: 10000 times, acceleration voltage: 2 kV). Analyzer LUZEX AP (manufactured by JEOL Ltd.) Automatic image processing analysis system LUZEX (registered trademark) AP software Ver. After importing into 1.32 (manufactured by Nireco Corporation) and binarizing the photographic image with the maximum value +30 level of the monochrome histogram as the threshold value (see (b) in FIG. 6), the distance between adjacent centers of gravity is calculated. , The average distance R (nm) between the convex portions of the convex portion structure was obtained, and the obtained results are shown in Table I.

The configuration of each photoconductor obtained as described above is shown in Table I.

<< Evaluation of photoconductor >>
A full-color printing machine (“bizhub PRESS® C658”, manufactured by Konica Minolta KK) was used for the following evaluation. The Bizhub C658 is a multi-function peripheral (MFP) type color multifunction device (MFP) that performs laser exposure at a wavelength of 780 nm, intermediate transfer for reverse development, and the above-mentioned prepared photoconductor.

Next, in a normal temperature and humidity environment (temperature 20 ° C., humidity 50% RH), 200,000 A4 size images having a print area ratio of 10% for each color of YMCK are printed and output on A4 size neutral paper, and then the method shown below is used. Each evaluation was performed according to.

(1) Evaluation of abrasion resistance of the photoconductor After printing 200,000 sheets, the evaluation was made based on the amount of film thickness wear of the protective layer of the photoconductor before and after the durability test. Specifically, the film thickness of the protective layer is measured at 10 places at random at the uniform film thickness portion (the film thickness fluctuating portion at the front end portion and the rear end portion of the coating is excluded by preparing a film thickness profile). The average value is taken as the film thickness of the protective layer.

The film thickness measuring device used was an eddy current type film thickness measuring device "EDDY560C" (manufactured by HELMUT FISCHER GMBTE CO), and the difference in film thickness of the protective layer before and after the durability test was calculated as the film thickness depletion amount (μm). .. When the evaluation result was from "A" to "D", it was judged to be practical.

A: Film thickness wear is less than 0.05 μm B: Film thickness wear is 0.05 μm or more and less than 0.10 μm C: Film thickness wear is 0.10 μm or more and less than 0.15 μm D: Film thickness wear is 0.15 μm or more, less than 0.20 μm E: Film thickness wear amount is 0.20 μm or more

(2) Evaluation of slip-through resistance After printing 200,000 sheets in the above normal temperature and humidity environment (temperature 20 ° C, humidity 50% RH), the paper is placed in a low temperature and low humidity environment (temperature 10 ° C, humidity 20% RH). The halftone image with a coverage rate of 80% shown in FIG. 8A was printed on 20,000 sheets of A3 size neutral paper so that the black part was located in the front part and the white part was located in the rear part in the transport direction. The white background of the 20,000th sheet of paper was visually observed to evaluate the slip-through of the toner. When the evaluation results were "A" and "B", it was judged to be practical.

A: No stains were found on the white background B: Minor streak-like stains were generated on the white background, but there was no practical problem C: Clear streak-like stains were generated on the white background, and it was practically used. Have a problem

(3) Evaluation of fine line reproducibility After printing 200,000 sheets in the above room temperature and humidity environment (temperature 20 ° C., humidity 50% RH), in a high temperature and high humidity environment (temperature 30 ° C., humidity 80% RH). The image shown in FIG. 8B having a 1-dot line was printed on A3 size POD glass-coated paper, and the line width of the output image was compared with the line width of the original image to evaluate the fine line reproducibility. It was judged that the case where the evaluation result was "A" to "C" was practical.

A: Any black line is formed with a constant line width without interruption B: The line width of the diagonal black line is partially narrowed or disturbed but not interrupted C: Vertical or horizontal black The line width is partially narrowed or disturbed, but it is not interrupted. D: There is a part where the black line is interrupted. E: The black line is not formed.

The results obtained above are shown in Table II.

As is clear from the results shown in Table II, the photoconductor of the present invention has excellent friction resistance as compared with the comparative example, and the electrophotographic image formed by using the photoconductor of the present invention has slip-through resistance and fine line reproducibility. It can be seen that the excellent effect is exhibited.

More specifically, in the photoconductors of the present invention, the surface modifiers 3 to 11 produced by changing the content of the surface modifier contained in the resin to 0.005 to 0.55 parts are the surface modifiers. It can be seen that in the photoconductors 4 to 10 in which the content of the above is in the range of 0.01 to 0.5 parts, the photoconductor friction resistance and the fine line reproducibility are more excellent.

Regarding the average distance R between the convex portions on the surface, the average distance R between the convex portions is 100 to 250 nm in the photoconductors 12 to 16 produced in the range of the average distance R between the convex portions of 80 to 280 nm. It can be seen that the photoconductors 13 to 15 within the range exhibit more excellent effects.

Further, comparing the photoconductor 14 and the photoconductor 17, the photoconductor 14 to which the surface modifier having a polymerizable group is applied to the metal oxide particles has a surface modifier having a polymerizable group. It can be seen that the photoconductor 17 is more effective than the photoconductor 17 not applied.

1Y, 1M, 1C, 1Bk Photoreceptor 2Y, 2M, 2C, 2Bk Charging means 3Y, 3M, 3C, 3Bk Exposure means 4Y, 4M, 4C, 4Bk Developing means 5Y, 5M, 5C, 5Bk Primary transfer roller 5b Secondary transfer Roller 6Y, 6M, 6C, 6Bk, 6b Cleaning means 7 Intermediate transfer unit 8 Housing 10Y, 10M, 10C, 10Bk Image forming unit 11 Protective layer 12 Surface modifier (in resin)
13 Resin 14A, 14B Surface-modified metal oxide particles 15 Metal oxide particles (inorganic filler)
16, 17 Surface modifier (particle surface)
20 Paper cassette 21 Paper feed means 22A, 22B, 22C, 22D Intermediate roller 23 Resist roller 24 Fixing means 25 Paper discharge roller 26 Paper discharge tray 41 Mother liquid tank 41a Stirring blade 41b 1st shaft 41c 1st motor 42 1st piping 43 Strong dispersion device 43a Stirrer 43b 2nd shaft 43c 2nd motor 44 2nd piping 45 1st pump 46 2nd pump S1, S3 Flow velocity 70 Intermediate transfer body 71, 72, 73, 74 Roller 77 Intermediate transfer body 82L, 82R Support Rail 100 Image forming device 101A, 101B Electrophotographic photosensitive member 102 Conductive support 103 Intermediate layer 104 Photosensitive layer 105 Outer layer 106 Charge generating layer 107 Charge transporting layer A Same structure part B Reactive group SC Original image reading device P Transfer material

Claims (11)

An electrophotographic photosensitive member having a protective layer containing at least a resin and metal oxide particles.
The metal oxide particles are surface-modified with a surface modifier, and the metal oxide particles are surface-modified.
Apart from the surface modifier that modifies the surface of the metal oxide particles, the resin contains a compound having the same structural portion as the residue of the surface modifier. Photophotoreceptor. The content of the compound having the same structural portion as the residue of the surface modifier in the resin is in the range of 0.01 to 0.5 parts by mass with respect to 1 part by mass of the resin. The electrophotographic photosensitive member according to claim 1. The content of the compound having the same structural portion as the residue of the surface modifier in the resin is in the range of 0.02 to 0.25 parts by mass with respect to 1 part by mass of the resin. The electrophotographic photosensitive member according to claim 1 or 2. The surface of the protective layer has a plurality of protrusions and has a plurality of protrusions.
Any one of claims 1 to 3, wherein the average distance R between the convex portions of the convex portion structures adjacent to each other is within the range of 100 to 250 nm among the plurality of convex portions. The electrophotographic photosensitive member according to. The electrophotographic photosensitive member according to any one of claims 1 to 4, wherein the protective layer contains a polymerized cured product of a composition containing a polymerizable monomer and metal oxide particles. The electrophotographic photosensitive member according to any one of claims 1 to 5, wherein the surface modifier has an alkyl fluoride chain. The electrophotographic photosensitive member according to claim 6, wherein the alkyl fluoride chain is contained in the side chain of the surface modifier. The electrophotographic photosensitive member according to any one of claims 1 to 5, wherein the surface modifier has a silicone chain. The electrophotographic photosensitive member according to claim 8, wherein the silicone chain is contained in the side chain of the surface modifier. The electrophotographic photosensitive member according to any one of claims 1 to 9, wherein the metal oxide particles have a polymerizable group. An electrophotographic image forming apparatus comprising the electrophotographic photosensitive member according to any one of claims 1 to 10.

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