JP2003066638A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having excellent sensitivity and electrification characteristics, high stability of these characteristics for repeated use and practically sufficient performances. SOLUTION: In the electrophotographic photoreceptor, titanium oxide particles at least either in an acicular form or dendritic form are incorporated into the base coating layer on the conductive base body. A butyral resin expressed by general formula (1) is incorporated as a binder resin into the charge generating layer. A polymer compound having the structural unit expressed by general formula (2) is incorporated as a binder resin into the charge transfer layer. In formula (1), R<0> represents a hydrogen atom, a methyl group or an ethyl group and each of j, k, l and m represents an integer. In formula (2), each of R<1> , R<2> , R<3> , R<4> , R<5> , R<6> , R<7> and R<8> represents a hydrogen atom, halogen atom, 1-6C alkyl group which may have substituents, 4-10C cyclic hydrocarbon group which may have substituents or aryl group which may have substituents.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member used in an electrophotographic apparatus such as a copying machine and a laser printer.

[0002]

2. Description of the Related Art Conventionally, as a photoconductive material for an electrophotographic photosensitive member (hereinafter, also simply referred to as "photosensitive member"), Se,
Inorganic materials such as CdS and ZnO ₂ have been used, but since they have problems such as toxicity, they are organic pollution-free in recent years, have excellent film-forming properties, and have a wide selection range of materials. Has come to be used, and electrophotographic photoreceptors using the same have been actively developed. An organic electrophotographic photosensitive member using the organic photoconductive material includes a charge generation material and a single layer type in which a charge generation material and, if necessary, a charge transport material which is a photoconductive material are dispersed in a binder resin. And a charge transport layer containing a charge transport material may be laminated to be a laminated type in which the functions are separated.

The single-layer type photoconductor has a structure in which a charge generating material and a charge transporting material are co-dispersed, and is easy to produce.
It has been put to practical use because of its low cost and the fact that it can be used in a process in which ozone, which is a harmful substance, is unlikely to be generated, and is disclosed in Japanese Examined Patent Publication No. 50-10496 and Japanese Unexamined Patent Publication No. 3-59661. Has been done. For example, Japanese Patent Application Laid-Open No. 3-59691 proposes an electrophotographic photoreceptor using a perylene pigment and a phthalocyanine pigment as a charge generating material. On the other hand, the laminated-type photoreceptor is the mainstream of organic electrophotographic photoreceptors because the photosensitive layer can be easily designed and high sensitivity and stability can be obtained. Japanese Patent Publication No. 55-42380 and the like have proposed a number of electrophotographic photoreceptors in which a charge generation layer containing a specific compound and a charge transport layer are combined, and are now the center of the electrophotographic photoreceptors. .

In these organic photoconductors currently in practical use, the main problems are durability and stability, and in particular, the decrease of the charging potential due to the electrical and chemical changes of the film during repeated use. In addition, there is a problem that characteristics change such as increase in residual potential is likely to occur. These issues are
Printing durability of the photosensitive layer in the image forming process, where the latent image is created by charging and exposure, the toner image is transferred to the transfer paper, and the residual toner on the surface of the photoconductor is removed with a blade, etc. Is not sufficient, and the main factors are that the organic photoconductive compound in the film is modified or decomposed by light or ozone or nitrogen oxide exposed during the image forming process. Therefore,
In the organic photoreceptor, practically sufficient durability has not yet been ensured.

The performance required for the electrophotographic photosensitive member in the image forming process is, for example, that the surface potential when charged is high, the carrier retention rate is high, and the photosensitivity is high.
Moreover, there is little variation in these electrical characteristics under all environments. It is also required to have excellent wear resistance in repeated use and high stability of electric characteristics throughout life. Furthermore, in order to improve the production efficiency, the electrophotographic photosensitive member is required to be prepared by a photosensitive member coating liquid that is physically and chemically stable. To meet these requirements, the charge generating material in the photosensitive layer,
The charge-transporting material, the binder resin contained in the charge-transporting layer which also serves as the outermost surface layer of the photoconductor, and the additives have been actively developed. However, the binder resin contained in the undercoat layer or the charge-generating layer, and these There has not been much research on the combination of a charge transport material with a charge transport material.

Conventionally, general-purpose butyral resin and polyester resin have been studied as the binder resin contained in the charge generation layer, and granular titanium oxide, tin oxide or aluminum oxide as the inorganic fine particle powder contained in the undercoat layer. Particles are being studied. However, there are problems that the sensitivity of the photoconductor decreases and the residual potential increases after repeated use.Therefore, we have not found a combination that sufficiently satisfies the basic performance such as dispersion stability of particles and separation and injection of generated charges. It has not been issued. In particular, polyvinyl butyral resin is not sufficiently durable against repeated use, and when a photoreceptor using the polyvinyl butyral resin is used under high temperature and high humidity, the generated charge is affected by the moisture absorbed by the polyvinyl butyral resin. In response to this, it is trapped in the charge generation layer, and the sensitivity is lowered and the residual potential is increased. Further, Japanese Patent No. 2784657 proposes an electrophotographic photosensitive member which is a combination of a charge generation layer containing a specific binder resin and a charge transport layer containing a specific binder resin, but the practical sensitivity is insufficient. Not only that, it cannot be said to have high reliability because defective image density and background fogging occur due to a decrease in charging potential and an increase in residual potential during repeated use.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor having excellent sensitivity characteristics and charging characteristics, high stability of these characteristics upon repeated use, and sufficient performance for practical use. It is to be.

[0008]

According to the present invention, an undercoat layer, a charge generating layer containing a charge generating material and a binder resin, and a charge transporting layer containing a charge transporting material and a binder resin are provided on a conductive substrate. And a binder resin for the charge generation layer, wherein the undercoat layer contains at least needle-shaped or dendritic titanium oxide particles. An electrophotographic photoreceptor comprising a butyral resin represented by the formula (1), wherein the binder resin of the charge transport layer comprises a polymer compound having a structural unit represented by the following general formula (2). .

[0009]

[Chemical 3]

(In the formula, R ⁰ represents a hydrogen atom, a methyl group or an ethyl group, and j, k, l and m represent integers.)

[0011]

[Chemical 4]

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ ,
R ⁷ and R ⁸ are each a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, a cyclic hydrocarbon group having 4 to 10 carbon atoms which may have a substituent, or It represents an aryl group which may have a substituent. )

According to the present invention, by containing needle-like or dendritic titanium oxide in the undercoat layer, it is possible to avoid a decrease in sensitivity and an increase in residual potential due to charge accumulation in the undercoat layer. By including the polycarbonate resin A having the structural unit represented by the general formula (2) in the charge transport layer, the wear resistance is excellent and the compatibility with the charge transport material is excellent, so that the electrical characteristics are deteriorated. Never.
Furthermore, by including the butyral resin represented by the general formula (1) in the charge generation layer, the matching property between the electronic injection level and the trap level of each material, the carrier mobility of the charge transport material, and the molecular dispersion. The excellent photoconductor characteristics are obtained by reflecting the superiority of the charge-transporting material based on the physical and chemical interactions, and the sensitivity characteristics and the charging characteristics are excellent. It is possible to provide an electrophotographic photosensitive member having a practically sufficient performance with a small potential increase.

Further, the present invention is characterized in that the polymer compound has a viscosity average molecular weight of 30,000 or more and 70,000 or less.

According to the present invention, when the viscosity average molecular weight of the above-mentioned polymer compound is 30,000 to 70,000, the printing durability is remarkably lowered and the viscosity average molecular weight is less than 30,000. It is possible to avoid that the viscosity is larger than 70,000 and the viscosity of the coating solution is increased, it takes a long time to mix with the charge transport material, and unevenness of the coating film is likely to occur, thereby lowering productivity.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The electrophotographic photosensitive member according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing the layer structure of a laminated type photoreceptor according to an embodiment of the present invention. Provided on the conductive support 1 is an undercoat layer 6, and a photosensitive layer 20 composed of a laminate of a charge generation layer 3 containing a charge generation material 2 and a charge transport layer 5 containing a charge transport material 4. It is a laminated type photoconductor. The undercoat layer 6 contains titanium oxide particles having a specific shape, the charge generation layer 3 contains a specific binder resin 7, and the charge transport layer 5 contains a specific binder resin 8. The laminated type photoreceptor is obtained by applying a dispersion liquid obtained by dispersing particles of the charge generating material 2 in a solvent or a binder resin 7 onto the undercoat layer 6 formed on the conductive support 1. To form the charge generation layer 3, and a solution in which the charge transport material 4 and the binder resin 8 are dissolved is applied thereon to form the charge transport layer 5
It can be produced by forming and drying.

The conductive support 1 serves not only as an electrode of the photosensitive member but also as a support for each of the other layers, and the shape thereof may be any of a cylindrical shape, a plate shape, a film shape and a belt shape. Examples of the material for the conductive support 1 include metal materials such as aluminum, stainless steel, copper and nickel, and polyester films having a conductive layer such as aluminum, copper, palladium, tin oxide and indium oxide on the surface thereof, and phenol. Examples include insulating materials such as resin pipes and paper pipes. Volume resistance is 10 ¹⁰
It is preferable to have conductivity of Ωcm or less, and the surface may be subjected to an oxidation treatment for the purpose of adjusting the volume resistance.

The undercoat layer 6 comprises a conductive support 1 and a photosensitive layer 2.
0 and contains at least needle-like or dendritic titanium oxide particles.

The needle shape means an elongated shape including a rod shape, a column shape, and a spindle shape, and the ratio a of the major axis length a to the minor axis length b.
/ B indicates a shape having an aspect ratio of 1.5 or more. Therefore, it does not have to be extremely elongated,
It is not necessary for the tip to be sharp. The average value of the aspect ratio is preferably 1.5 or more and 300 or less, more preferably 2 or more and 10 or less. If it is smaller than this range, it is difficult to obtain the needle-like effect, and if it is larger than this range, the needle-like effect does not change.

The term "dendritic" refers to a branch having a long and narrow shape including a rod shape, a column shape, and a spindle shape. Even in the dendritic form, the elongated shape does not necessarily have to be extremely elongated, and it is not necessary for the tip to be sharp. The major axis length a of the dendritic titanium oxide particles is 10
It is preferable that the minor axis length b is 0 μm or less and the minor axis length b is 1 μm or less, and more preferably, the major axis length a is 10 μm or less and the minor axis length b is 0.5.
μm or less. If the particle size is not within this range, it is difficult to obtain a coating solution for an undercoat layer having dispersion stability even if surface treatment is performed with a metal oxide or an organic compound.

The aspect ratio and the particle size can be measured by a method such as a weight sedimentation method or a light transmission type particle size distribution measuring method, but since they are needle-like or dendritic, it is preferable to measure them directly by an electron microscope.

The titanium oxide particles may be used by mixing granular particles with acicular or dendritic particles. With respect to needle-shaped, dendritic, and granular particle-shaped titanium oxide, there are anatase-type, rutile-type, amorphous, and the like as crystal forms, and any of them may be used.
You may use it in mixture of 2 or more types.

The content of the acicular or dendritic titanium oxide particles is preferably 10% by weight or more and 99% by weight or less, more preferably 30% by weight or more and 99% by weight or less, and most preferably 35% by weight. It is in the range of 95% by weight or more. When the content is less than 10% by weight, the sensitivity is lowered, the electric charge is accumulated in the undercoat layer, and the residual potential is increased. In particular, it becomes remarkable in the repeated characteristics under low temperature and low humidity. When the content is more than 99% by weight, the storage stability of the coating liquid for the undercoat layer is deteriorated and the precipitation of titanium oxide particles is apt to occur, which is not preferable.

The coating liquid for the undercoat layer preferably contains a binder resin. By containing a binder resin in the coating solution for the undercoat layer containing the needle-shaped or dendritic titanium oxide particles, the dispersibility of titanium oxide in the coating solution for the undercoat layer is maintained for a long time, This is because a uniform film can be formed as a layer.

The volume resistance value of the powder of titanium oxide particles is preferably 10 ⁵ to 10 ¹⁰ Ωcm. When the volume resistance value of the powder is smaller than 10 ⁵ Ωcm, the resistance value as the undercoat layer is lowered and the powder does not function as the charge blocking layer. For example, in the case of metal oxide particles that have been subjected to a conductive treatment such as a tin oxide conductive layer doped with antimony,
The volume resistance value of the powder is extremely low at 10 ⁰ to 10 ¹ Ωcm. The undercoating layer using this does not function as a charge blocking layer, the chargeability as a characteristic of the photoreceptor is deteriorated, and fog and black spots are generated in the image, so that it cannot be used. Further, the volume resistance value of the powder of titanium oxide particles is 10 ¹⁰
If it is higher than Ωcm and is equal to or higher than the volume resistance value of the binder resin contained in the undercoat layer, the resistance value as the undercoat layer is too high, and the transport of the charge generated during light irradiation is suppressed or blocked. However, the residual potential increases and the photosensitivity decreases, which is not preferable.

The surface of the acicular or dendritic titanium oxide particles is preferably coated with a metal oxide as long as the volume resistance value of the powder of the titanium oxide particles is maintained within the above range. When the surface-untreated titanium oxide particles are used, since the particles are fine particles, even if the coating liquid for the undercoat layer is sufficiently dispersed, the titanium oxide particles do not aggregate during long-term use or storage of the coating liquid. I can't avoid it. When this undercoat layer coating liquid is used, when the undercoat layer 6 is formed, defects in the coating film and coating unevenness occur, resulting in image defects. In addition, since the injection of charges from the conductive support 1 is likely to occur, the charging property of the minute area is lowered and black spots are generated. By coating the surface of the titanium oxide particles with a metal oxide, the aggregation of titanium oxide can be prevented, and a coating liquid for an undercoat layer having excellent dispersibility and storage stability can be obtained. By using such a coating liquid for the undercoat layer, injection of charges from the conductive support 1 can be prevented, so that an electrophotographic photoreceptor having excellent image characteristics without black spots can be obtained.

Examples of the metal oxide include Al ₂ O ₃ and Zr.
O ₂ and mixtures thereof are preferred. In particular, when the surface treatment is performed with both of the different metal oxides, Al ₂ O ₃ and ZrO ₂ , more excellent image characteristics are obtained, so that more preferable effects are exhibited. When the surface treatment is performed with SiO ₂ or the like, the surface shows hydrophilicity so that it becomes difficult to adapt to an organic solvent, so that the dispersibility of titanium oxide decreases and aggregation easily occurs, which is preferable for long-term use. Absent. When titanium oxide surface-treated with a magnetic metal oxide such as Fe ₂ O ₃ is used, when a phthalocyanine pigment is contained in the photosensitive layer as a charge generating material, phthalocyanine pigment and Fe ₂ O ₃ Is not preferable because the photoreaction of the photosensitivity occurs, resulting in deterioration of the photoreceptor characteristics, particularly sensitivity and chargeability.

Al ₂ O ₃ used as the metal oxide
The amount of surface treatment with or ZrO ₂ is preferably 0.1% by weight to 20% by weight with respect to titanium oxide. If the amount of treatment is less than 0.1% by weight, the surface of titanium oxide cannot be sufficiently covered, so that the effect of the surface treatment is less likely to be exhibited. If the treatment amount exceeds 20% by weight, the surface treatment is sufficiently performed, but since the characteristic amount is the same as the treatment amount of 20% by weight, even if the treatment amount exceeds 20% by weight, the cost will be high. Is not preferable.

The surface of the acicular or dendritic titanium oxide particles may be coated with an organic compound. As the organic compound, a general coupling agent can be used. Examples of the type of coupling agent include silane coupling agents such as alkoxysilane compounds, silylating agents in which atoms such as halogen, nitrogen and sulfur are bonded to silicon, titanate coupling agents, and aluminum coupling agents. To be

As the silane coupling agent, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, ethyltrimethoxysilane, diethyldimethoxysilane, phenyltriethoxysilane,
Aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, 3
-(1-Aminopropoxy) -3,3-dimethyl-1-
Propenyltrimethoxysilane, (3-acryloxypropyl) trimethoxysilane, (3-acryloxypropyl) methyldimethoxysilane, (3-acryloxypropyl) dimethylmethoxysilane and N-3- (acryloxy-2-hydroxypropyl) Examples include alkoxysilane compounds such as -3-aminopropyltriethoxysilane.

Examples of the silylating agent include chlorosilanes such as methyltrichlorosilane, methyldichlorosilane, dimethyldichlorosilane and phenyltrichlorosilane, and silazanes such as hexamethyldisilazane and octamethylcyclotetrasilazane.

Examples of the titanate coupling agent include isopropyltriisostearoyl titanate and bis (dioctyl pyrophosphate). Examples of the aluminum-based coupling agent include acetoalkoxy aluminum diisopropylate. The coupling agent is not limited to these specific examples. These coupling agents can also be used as a dispersant by subjecting titanium oxide particles to a surface treatment, and in that case, they may be used alone or in combination of two or more kinds.

The method of subjecting the titanium oxide particles to the surface treatment is as follows:
The method is roughly divided into a pretreatment method and an integral blend method, and the pretreatment method is further divided into a wet method and a dry method. The wet method is divided into a water treatment method and a solvent treatment method. As the water treatment method, known methods such as a direct dissolution method, an emulsion method and an amine adduct method can be used.

When the surface of titanium oxide particles is treated with a coupling agent, before or after the treatment, and when the coupling agent is added as a dispersant to an organic solvent, the powder of titanium oxide particles is used. The surface of the titanium oxide particles may be untreated or coated with a metal oxide such as Al ₂ O ₃ , ZrO ₂ and a mixture thereof, as long as the volume resistance value of the body is maintained within the above range.

As the binder resin contained in the undercoat layer 6, polyvinyl alcohol, casein, polyvinylpyrrolidone, polyacrylic acid, celluloses, gelatin,
Resins such as starch, polyurethane, polyimide and polyamide can be used, and polyamide resin is preferably used. The reason for this is that the polyamide resin does not dissolve or swell in the solvent used in the photosensitive layer coating liquid for forming the photosensitive layer 20 on the undercoat layer 6, and the polyamide resin does not dissolve in the conductive support 1. This is because it has properties required for the properties of the binder resin, such as excellent adhesiveness and flexibility. Among the polyamide resins, alcohol-soluble nylon resin can be used more preferably. For example, 6-nylon, 66-nylon, 61
Nylon is chemically modified, such as 0-nylon, 11-nylon and 12-nylon copolymerized so-called copolymerized nylon, and N-alkoxymethyl modified nylon and N-alkoxyethyl modified nylon. There are types.

As the organic solvent used in the coating liquid for the undercoat layer, a general organic solvent can be used. However, when an alcohol-soluble nylon resin, which is a more preferable polyamide resin, is used as the binder resin, a single or mixed organic solvent selected from the group of lower alcohols having 1 to 4 carbon atoms, or the lower alcohols described above. The organic solvent selected from the group includes, for example, dichloromethane, chloroform, 1,2-dichloroethane, 1,
It is preferable to use a mixed organic solvent in which an organic solvent selected from the group consisting of organic solvents other than lower alcohols such as 2-dichloropropane, toluene, tetrahydrofuran and 1,3-dioxolane is mixed. By mixing an organic solvent selected from the lower alcohol group with an organic solvent other than the lower alcohol, the dispersibility of titanium oxide is improved as compared with the case where only the organic solvent of the lower alcohol group is used, and the storage stability of the coating solution ( The number of days elapsed from the preparation of the coating liquid for the undercoat layer will be referred to as "pot life" hereinafter), and the coating liquid can be regenerated. In addition, the conductive support 1 is dipped in the coating liquid for the undercoat layer and coated to form the undercoat layer 6.
When forming the undercoat layer, coating defects and unevenness of the undercoat layer 6 are prevented, and the photosensitive layer 20 formed thereon can be uniformly coated. Therefore, electrophotography having very excellent image characteristics without film defects. A photoreceptor can be produced.

As a method for dispersing the coating liquid for the undercoat layer, there is a method using a ball mill, a sand mill, an attritor, a vibration mill, an ultrasonic disperser or the like. As a method of applying the undercoat layer coating liquid, a general method such as the above-mentioned dip coating method can be applied.

The thickness of the undercoat layer 6 is preferably 0.01.
The range is from μm to 20 μm, and more preferably from 0.05 μm to 10 μm. The undercoat layer 6 has a thickness of 0.
If it is thinner than 01 μm, it will not substantially function as an undercoat layer. That is, the defects of the conductive support 1 cannot be covered to obtain a uniform surface property, the injection of charges from the conductive support 1 cannot be prevented, and the chargeability decreases. In addition, it is not preferable to make the thickness of the undercoat layer 6 thicker than 20 μm, because when the undercoat layer 6 is applied by dip coating, it becomes difficult to manufacture the photoreceptor and the sensitivity of the photoreceptor is lowered.

The charge generation layer 3 is composed of a conventionally known charge generation material 2 and a specific binder resin 7.

The specific binder resin 7 is a butyral resin represented by the following general formula (1).

[0042]

[Chemical 5]

(In the formula, R ⁰ represents a hydrogen atom, a methyl group or an ethyl group, and j, k, l and m represent integers.)

In the general formula (1), j, k, l and m
Indicates the relative content of each structural unit. The relative content is not particularly limited as long as the four structural units represented by the general formula (1) are included.

The butyral resin represented by the above general formula (1) improves the sensitivity of the photoconductor by using the titanium oxide particles described above in combination with the binder resin of the charge transport layer to be described later, and the charging potential of repeated use is improved. It is possible to suppress a decrease and an increase in residual potential.

In the embodiment of the present invention, as the suitable charge generating material 2, any of inorganic pigments, organic pigments and organic dyes can be used as long as they absorb light and generate free charges. . Inorganic pigments include selenium and its alloys, arsenic-selenium, cadmium sulfide, zinc oxide, amorphous silicon, and other inorganic photoconductors. Organic pigments include phthalocyanine compounds, azo compounds, quinacridone compounds,
Examples thereof include polycyclic quinone compounds and perylene compounds. Examples of organic dyes include thiapyrylium salts and squarylium salts. As the charge generating material 2 in the embodiment of the present invention, the organic photoconductive compound such as an organic pigment or an organic dye is preferably used.
Among these, phthalocyanine compounds are preferable,
It is more preferable to use a titanyl phthalocyanine compound. By using the titanyl phthalocyanine compound, particularly good sensitivity characteristics, charging characteristics and repetitive characteristics can be obtained.

In addition to the pigments and dyes listed above, a chemical sensitizer or an optical sensitizer may be added to the charge generation layer 3. As the chemical sensitizer, electron-accepting materials, for example, cyano compounds such as tetracyanoethylene and 7,7,8,8-tetracyanoquinodimethane, quinones such as anthraquinone and p-benzoquinone, and 2, 4,7-trinitrofluorenone and 2,
Examples include nitro compounds such as 4,5,7-tetranitrofluorenone. Examples of the optical sensitizer include dyes such as xanthene dyes, thiazine dyes and triphenylmethane dyes.

In addition, the charge generation layer 3 may be, if necessary,
It may contain various additives such as a leveling agent, an antioxidant and a sensitizer for improving the coating property.

The charge generation layer 3 is formed by dispersing the charge generation material 2 described above together with the binder resin 7 in a suitable solvent, coating it on the undercoat layer 6, and drying or curing it to form a film. To do.

As the solvent, isopropyl alcohol,
Examples thereof include cyclohexanone, cyclohexane, toluene, xylene, acetone, methyl ethyl ketone, tetrahydrofuran, dioxane, dioxolane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene and ethylene glycol dimethyl ether. Solvents other than these may be used, and any of alcohol-based, ketone-based, amide-based, ester-based, ether-based, hydrocarbon-based, chlorinated hydrocarbon-based and aromatic-based solvent systems may be used alone or in combination. May be. However, considering the decrease in sensitivity due to the crystal transition during pulverization and milling of the charge generating material 2 and the decrease in characteristics due to the pot life, cyclohexanone, which is a solvent in which crystal transition is less likely to occur in both pigments,
It is preferable to use any one of 1,2-dimethoxyethane, methyl ethyl ketone and tetrahydroquinone.

As a method of forming the charge generation layer 3, generally, a vacuum vapor deposition method, a sputtering method and a CVD (Chemical
Vapor deposition method such as Vapor Deposition) and coating method are applied. In the coating method, the charge generating material 2 is pulverized by a ball mill, sand grinder, paint shaker, ultrasonic disperser or the like and dispersed in a solvent, and the coating solution prepared by adding the binder resin 7 is applied on the undercoat layer 6. Apply to. For example, when the conductive support 1 is a sheet, a baker applicator, a bar coater, casting, spin coating, or the like, and when the conductive support 1 is a drum, a spray method, a vertical ring method, or a dip coating method is used. To do. In particular, the dip coating method is preferable because it is excellent in mass productivity.

The thickness of the charge generation layer 3 is about 0.05 to 5 μm.
m is preferable, and more preferably about 0.1 to 1 μm.

The charge transporting layer 5 is provided on the charge generating layer 3 and contains the charge transporting material 4 and the specific binder resin 8 which have the ability to receive the charge generated by the charge generating material 2 and transport it. Contained as.

The specific binder resin 8 is a polycarbonate resin A which is a polymer compound having a structural unit represented by the following general formula (2).

[0055]

[Chemical 6]

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ ,
R ⁷ and R ⁸ are each a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, a cyclic hydrocarbon group having 4 to 10 carbon atoms which may have a substituent, or It represents an aryl group which may have a substituent. ) Table 1 shows specific examples of the structural unit represented by the general formula (2).

[0057]

[Table 1]

Since the polycarbonate resin A has an asymmetric structure, it is difficult to crystallize and the production efficiency is good. Also,
Since it has no bulky group, it can be densely packed to form a strong film when it is dried and solidified from the solution, and has excellent abrasion resistance. Furthermore, since the compatibility with the charge transport material 4 is excellent, the electrical characteristics are not deteriorated.

With respect to the molecular weight of the polycarbonate resin A, it is preferable that the viscosity average molecular weight is 30,000 to 70,000 from the viewpoint of the electrical characteristics of the photoconductor, the repeated stability and the printing durability. When the viscosity average molecular weight is less than 30,000, the compatibility with the charge transport material 3 is high and the repeated stability of electric characteristics is excellent, but the printing durability is significantly deteriorated. When it is more than 70,000, the printing durability is improved, but the viscosity of the coating liquid for the charge transport layer is increased, it takes a long time to mix with the charge transport material 4, and the coating film is likely to be uneven. And productivity is reduced.

The polycarbonate resin A may be used as a mixture with the polycarbonate resin B which is a polymer compound having a structural unit represented by the following general formula (3).

[0061]

[Chemical 7]

(Wherein R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ ,
R ¹⁴ , R ¹⁵ and R ¹⁶ are each a hydrogen atom, a halogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms,
It represents a cyclic hydrocarbon group having 4 to 10 carbon atoms which may have a substituent or an aryl group which may have a substituent. Z is
It is a group of atoms necessary for forming a carbocycle which may have a substituent or a heterocycle which may have a substituent. ) Table 2 shows specific examples of the structural unit represented by the general formula (3).

[0063]

[Table 2]

Since the polycarbonate resin B has a low gas permeability, it is possible to prevent the penetration of gases such as ozone and NO _x, which deteriorate the characteristics of the photoreceptor. In addition, the compatibility with the charge transport material 4 is excellent, and the durability is also excellent.

The polycarbonate resin B preferably has a viscosity average molecular weight of 15,000 to 35,000. When the viscosity average molecular weight is less than 15,000, halftone (HT) white spots and black bands due to ozone and NO _x generated in the charging process are suppressed and image stability is improved, but printing durability is improved. When the value is more than 35,000, the printing durability is improved, but the initial sensitivity decreases, the residual potential increases after repeated use, and the image stability decreases.

A mixture of the polycarbonate resins A and B has excellent compatibility with the charge transport material 4 and excellent durability. Ozone and NO _x generated in the charging process by adding the polycarbonate resin B
The occurrence of image defects due to active species such as is suppressed.

The mixing ratio A / B of the polycarbonate resin A and the polycarbonate resin B is A / B in terms of weight ratio.
Is preferably in the range of 2/8 to 8/2. A / B
Is smaller than 2/8, that is, polycarbonate resin A
When the ratio of is low, the desired mechanical strength cannot be obtained,
Scratches are likely to occur on the surface of the photoconductor. Conversely, A / B is 8
When the ratio is greater than / 2, that is, when the ratio of the polycarbonate resin B is low, ozone or NO _x deteriorates the photoreceptor characteristics, and HT white spots and black bands are likely to occur in the image.

As the charge transport material 4, an electron donating substance or an electron accepting substance is used. Examples of the electron-donating substance include poly-N-vinylcarbazole and its derivative, poly-γ-carbazolylethylglutamate and its derivative, pyrene-formaldehyde condensate and its derivative, polyvinylpyrene, polyvinylphenanthrene, oxazole derivative, and oxadiene. Azole derivative, imidazole derivative, 9- (p-diethylaminostyryl) anthracene, 1,1-bis (4-dibenzylaminophenyl) propane, styrylanthracene, styrylpyrazoline, pyrazoline derivative, phenylhydrazone, hydrazone derivative, triphenyl Amine compounds,
Tetraphenyldiamine compound, triphenylmethane compound, stilbene compound and 3-methyl-2-
Examples thereof include azine compounds having a benzothiazoline ring. The electron-accepting substance is a fluorenone derivative,
Dibenzothiophene derivative, indenothiophene derivative, phenanthrenequinone derivative, indenopyridine derivative, thioxanthone derivative, benzo [c] cinnoline derivative, phenazine oxide derivative, tetracyanoethylene, tetracyanoquinodimethane, bromanil, chloranil and benzoquinone Is mentioned. In particular, the butadiene-based compound represented by the following general formula (4), the styryl-based compound represented by the following general formula (5), and the amine-based compound represented by the following general formula (6) have high charge transporting ability, and therefore, are used as binders. High sensitivity can be maintained even when the ratio of the resin 8 is high, which is more preferable.

[0069]

[Chemical 8]

(Wherein Ar ¹ , Ar ² , Ar ³ and Ar ⁴
Each represents an aryl group which may have a substituent, and Ar
^At least one of ^{1 to} Ar ⁴ is an aryl group having a substituted amino group as a substituent. n represents 0 or 1. )

[0071]

[Chemical 9]

[0072] (wherein, Ar ⁵ is an optionally substituted aryl group, Ar ⁶ is a phenylene group which may have a substituent, a naphthylene group, a biphenylene group or anthrylene group .R ¹⁷ Represents a hydrogen atom, a lower alkyl group or a lower alkoxy group, X represents a hydrogen atom, an alkyl group which may have a substituent or an aryl group which may have a substituent, and Y represents a substituent. Represents an aryl group which may have.

[0073]

[Chemical 10]

(In the formula, R ¹⁸ , R ¹⁹ , R ²⁰ , R ²¹ , R ²² and R ²³ each represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group, and p, q, t and u respectively represent An integer of 1 to 5 and r and s each represent an integer of 1 to 4.)

Specific examples of the butadiene compound represented by the general formula (4) are shown in Tables 3 and 4.

[0076]

[Table 3]

[0077]

[Table 4]

Specific examples of the styryl compound represented by the general formula (5) are shown in Tables 5-8.

[Table 5]

[0079]

[Table 6]

[0080]

[Table 7]

[0081]

[Table 8]

Specific examples of the amine compound represented by the general formula (6) are shown in Tables 9 and 10.

[0083]

[Table 9]

[0084]

[Table 10]

The charge transport layer 5 is formed of these charge transport materials 4.
Is a binder resin 8 such as the polycarbonate resin A
It is formed in the form bound to.

In the charge transport layer 5, the ratio C / D between the charge transport material 4 (C) and the binder resin 8 (D) described above.
Is a generally used weight ratio of 10/5 to 10/2.
It is about 5, but from the viewpoint of improving wear resistance, it is 10/15
10/24 are suitable. When C / D is larger than 10/15, that is, when the ratio of the charge transport material 4 is high,
The light sensitivity characteristic is good, may decrease the mechanical strength of the charging characteristics and film, HT white spots and black bands generated by ozone and NO _x generated by the charging process, the image stability is lowered To do. When C / D is smaller than 10/24, that is, when the ratio of the binder resin 8 is high, conversely, the charging property, the mechanical strength and the image stability are good, but
The deterioration of the photosensitivity becomes remarkable.

The charge transport layer 5 contains a plasticizer, an antioxidant, and a plasticizer in order to improve film-forming property, flexibility and coating property.
You may contain additives, such as a ultraviolet absorber and a leveling agent. As the antioxidant, an antioxidant generally used by adding it to a resin or the like can be used as it is. For example, vitamin E, hydroquinone,
Hindered amines, hindered phenols, para-phenylenediamines, aryl alkanes and their derivatives, organic sulfur compounds and organic phosphorus compounds can be used. As the leveling agent, silicone oils or polymers or oligomers having a perfluoroalkyl group in the side chain can be used, and the amount used is preferably 1 part by weight or less relative to 100 parts by weight of the binder resin 8.

The charge transport layer 5 comprises the above-mentioned charge transport material 4,
The binder resin 8 and the additives are dissolved or dispersed in a suitable solvent to prepare a coating liquid, and the coating liquid is applied to the charge generation layer 3 by the same method as that for the undercoat layer 6 and the charge generation layer 3 described above. It is formed by applying to. The solvent can be selected from the above-mentioned solvents listed as the solvent for dispersing the charge generating material 2. For example, alcohols such as methanol and ethanol, ketones such as acetone, methyl ethyl ketone and cyclohexanone,
Ethers such as ethyl ether and tetrahydrofuran, aliphatic halogenated hydrocarbons such as chloroform, dichloroethane and dichloromethane, aromatic hydrocarbons such as benzene, chlorobenzene and toluene are used. A particularly preferred solvent is tetrahydrofuran.

The coating solution for the charge transport layer may be prepared by a general method in which the charge transport material 4, the binder resin 8 and the additive are weighed and dissolved in a predetermined amount of the solvent at the same time. It is particularly preferable to dissolve 8 in a solvent and then add the charge transport material 4 and an additive to dissolve them. According to this method, the molecular dispersibility of the charge transport material 4 in the binder resin 8 is improved, and latent and local crystallization of the charge transport material 4 in the film is suppressed, whereby the initial sensitivity is improved. Improvement, potential stability at repeated use, and good image characteristics are imparted.

The thickness of the charge transport layer 6 is about 10 to 50 μm.
Is preferable, and more preferably about 10 to 35 μm.

If necessary, a protective layer may be provided on the photosensitive layer 20 to protect the surface of the photosensitive layer. A thermoplastic resin and a light or thermosetting resin can be used for the surface protective layer. The protective layer may contain an ultraviolet absorber, an antioxidant, an inorganic material such as a metal oxide, an organometallic compound and an electron accepting substance. Further, in the same way as the photosensitive layer 20, the protective layer may be mixed with a plasticizer such as a dibasic acid ester, a fatty acid ester, a phosphoric acid ester, a phthalic acid ester and a chlorinated paraffin, if necessary, to improve the processability and the plasticity. May be added to improve mechanical properties, and additives such as a leveling agent may be mixed.

The undercoat layer 6 containing the above-mentioned acicular or dendritic titanium oxide particles, the charge generation layer 3 containing the butyral resin represented by the general formula (1), and the charge transport containing the polycarbonate resin A. In combination with layer 5, good photoreceptor properties can be obtained. The reason for this is not clear, but the matching property between the electronic injection level and the trap level of each material, the charge mobility of the charge transporting material 4, and the physical and chemical interaction of the molecularly dispersed charge transporting material 4 with each other. It is considered to reflect the superiority based on the action.

(Examples) Hereinafter, the electrophotographic photosensitive member according to the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following Examples as long as the gist thereof is not exceeded.

Example 1 5 parts by weight of titanium oxide (STR-60N manufactured by Sakai Chemical Industry Co., Ltd.), which was not treated with a needle-shaped surface, and 5 parts by weight of a copolymerized nylon resin (CM8000 manufactured by Toray) were used.
In addition to 90 parts by weight of tetrahydrofuran, it was dispersed for 12 hours using a paint shaker to prepare a coating liquid for undercoat layer having a solid content of 10% by weight. The prepared coating liquid for the undercoat layer is filled in a coating tank, and an aluminum drum-shaped support having a diameter of 30 mm and a total length of 322.3 mm is immersed as a conductive support, pulled up, and naturally dried to have a film thickness of 1 μm. Layers were formed.

Next, 1 part by weight of titanyl phthalocyanine and 1 part by weight of butyral resin (# 6000-C manufactured by Denki Kagaku Kogyo Co., Ltd.) represented by the general formula (1) are added.
In addition to 98 parts by weight of dioxolane, glass beads having a diameter of 2 mm were milled with a paint conditioner device (manufactured by Red Level Co.) as a dispersion aid to prepare a charge generation layer coating solution. The prepared charge generation layer coating liquid was applied onto the previously formed undercoat layer in the same manner as the above-mentioned undercoat layer, and then naturally dried to form a charge generation layer having a thickness of 0.2 μm.

Then, a butadiene compound (T405 manufactured by Anan Co.) represented by the structural formula (4-2) shown in Table 3 is used.
0 parts by weight, 80 parts by weight of a polycarbonate resin having a structural unit represented by the structural formula (2-1) shown in Table 1 and having a viscosity average molecular weight of 50,000, and the structural formula (3
-1) Viscosity average molecular weight 2 having a structural unit represented by 1)
80 parts by weight of 1,500 polycarbonate resin (PCZ200 manufactured by Mitsubishi Gas Chemical Company) and 2,6-bis-tert
5 parts by weight of -butyl-4-methylphenol (Sumilyzer BHT manufactured by Sumitomo Chemical Co., Ltd.) were mixed to prepare a charge transport layer coating solution having a solid content of 21% by weight using tetrahydrofuran as a solvent. The prepared charge transport layer coating liquid was applied onto the charge generation layer previously provided in the same manner as the above-mentioned undercoat layer, and then dried at 110 ° C. for 1 hour to form a charge transport layer having a thickness of 21 μm. .

In this way, a laminated electrophotographic photosensitive member having the layer structure shown in FIG. 1 was produced.

Example 2 A needle-shaped titanium oxide surface-treated with Al ₂ O ₃ and ZrO ₂ (TTO-M-1 manufactured by Ishihara Sangyo Co., Ltd.) was used in place of the needle-shaped surface-untreated titanium oxide.
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that was used.

Example 3 Oxidation of untreated needle-shaped surface
Instead of titanium, dendritic Al₂O₃And ZrO ₂Table
Surface-treated titanium oxide (Itohara Sangyo TTO-D-
An electrophotographic image was obtained in the same manner as in Example 1 except that 1) was used.
An optical body was produced.

Example 4 In the binder resin for the charge transport layer, a polycarbonate resin having a structural unit represented by the structural formula (2-1) was used, and a viscosity average molecular weight of 50,
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that a viscosity average molecular weight of 25,000 was used instead of the 000.

(Example 5) In the binder resin for the charge transport layer, a polycarbonate resin having a structural unit represented by the structural formula (2-1) was used, and a viscosity average molecular weight of 50,
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that a viscosity average molecular weight of 75,000 was used in place of that of 5,000.

However, since the coating liquid for the charge transport layer became highly viscous and the film thickness was uneven, a polyethylene terephthalate film (aluminum-deposited polyethylene terephthalate film) was used as the conductive support instead of the aluminum drum-shaped support. A thickness of 100 μm) was used, and an undercoat layer, a charge generation layer, and a charge transport layer were applied thereon by an applicator and dried to prepare an electrophotographic photoreceptor. The film thickness and drying conditions were the same as in Example 1. The produced electrophotographic photosensitive member was attached to a drum-shaped support having the same shape and size as those used in Example 1 to obtain an electrophotographic photosensitive member for evaluation.

Example 6 In a binder resin for a charge transport layer, a polycarbonate resin having a structural unit represented by the structural formula (2-1) was used, and a viscosity average molecular weight of 50,
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that a viscosity average molecular weight of 30,000 was used in place of that of 000.

Example 7 As a charge transport material for the charge transport layer, instead of the butadiene compound represented by the structural formula (4-2), the styryl represented by the structural formula (5-8) shown in Table 6 was used. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the system compound was used.

Example 8 As a charge transport material for the charge transport layer, an amine represented by the structural formula (6-1) shown in Table 9 was used instead of the butadiene compound represented by the structural formula (4-2). An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the system compound was used.

Example 9 As a charge transport material for a charge transport layer, 4-dibenzylamino-2-methylbenzaldehyde-1,1-diphenyl was used instead of the butadiene compound represented by the structural formula (4-2). An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that hydrazone was used.

(Example 10) As a binder resin for the charge transport layer, only 160 parts by weight of a polycarbonate resin having a viscosity average molecular weight of 50,000 having a structural unit represented by the structural formula (2-1) was used. An electrophotographic photosensitive member was produced in the same manner as in Example 1.

(Comparative Example 1) Example 1 was repeated, except that a granular surface-untreated titanium oxide (TTO-55N manufactured by Ishihara Sangyo Co., Ltd.) was used in place of the needle-shaped surface-untreated titanium oxide. An electrophotographic photoreceptor was prepared in the same manner.

(Comparative Example 2) The same procedure as in Example 1 was carried out except that only 160 parts by weight of the modified polycarbonate resin having the structural unit represented by the following structural formula (7) was used as the binder resin for the charge transport layer. An electrophotographic photoreceptor was produced.

[0110]

[Chemical 11]

Comparative Example 3 160% by weight of a polycarbonate resin having a viscosity average molecular weight of 21,500 (PCZ200 manufactured by Mitsubishi Gas Chemical Company) having a structural unit represented by the structural formula (3-1) as a binder resin for the charge transport layer. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that only a part was used.

(Comparative Example 4) As a binder resin for the charge generation layer, a butyral resin represented by the following structural formula (8) (S-manufactured by Sekisui Chemical Co., Ltd. was used instead of the butyral resin represented by the general formula (1)). An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that LEC BL-1) was used.

[0113]

[Chemical 12]

Comparative Example 5 As the binder resin for the charge generation layer, a vinyl chloride-vinyl acetate copolymer resin (SOLBINA manufactured by Nisshin Chemical Industry Co., Ltd.) was used instead of the butyral resin represented by the general formula (1). An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that it was used.

(Evaluation) The electrophotographic photosensitive members produced in the above Examples 1 to 10 and Comparative Examples 1 to 5 are commercially available copying machines as evaluation copying machines (AR-255FP manufactured by Sharp Corporation).
The halftone image was confirmed and the initial image characteristics were evaluated.

Further, the developing tank was taken out from the developing portion of the evaluation copying machine and replaced with a surface electrometer (Mode manufactured by Trek).
1344) is set and the surface potential V at the time of copying a white solid document is set.
0, the surface potential VH at the time of copying a halftone original, and the surface potential VL at the time of copying a black solid original were measured to evaluate the electrical characteristics.

Further, after copying 30,000 sheets of A4 paper, the halftone image was confirmed and the surface potential was measured in the same manner as in the initial stage, and the durability was evaluated from the change due to repeated use. Further, the amount of wear was obtained by measuring the film thickness of the photosensitive layer after repeated use. The results are shown in Table 11.

[0118]

[Table 11]

From Examples 1 to 10 and Comparative Examples 1 to 5, the electrophotographic photoreceptors of Examples contained needle-like or dendritic titanium oxide in the subbing layer, and the charge generation layer of the above general formula ( Since it contains the butyral resin represented by 1) and the polycarbonate resin A having the structural unit represented by the general formula (2) in the charge transport layer, it has better image characteristics and electrical characteristics as compared with Comparative Examples. understood.

Specifically, the photoconductor of Comparative Example 1 in which needle-like or dendritic titanium oxide was not used in the undercoat layer had good initial sensitivity, but after repeating 30,000 copies, it was good. I couldn't get a good image. It was found that the photoreceptor of Comparative Example 2 in which the polycarbonate resin A was not used in the charge transport layer had many scratches on the surface of the photoreceptor due to friction with a blade, paper, or the like, and when repeatedly used, the image characteristics deteriorate. In addition, the photoreceptor of Comparative Example 3 in which only the polycarbonate resin B having the structural unit represented by the general formula (3) is used in the charge transport layer and the polycarbonate resin A is not used, the image is adjusted with low sensitivity. It was not possible to obtain a good image. The photoconductors of Comparative Examples 4 and 5 which did not use the butyral resin represented by the general formula (1) in the charge generation layer had low sensitivity and could not obtain a good image even if the image was adjusted. The image got worse after repeated copies of 10,000 sheets.

In Example 4, since the viscosity average molecular weight of the polycarbonate resin A was small, the amount of wear was slightly increased. Further, in Example 5, the polycarbonate resin A
Since the viscosity average molecular weight of 1 is large, dip coating was difficult at the time of producing a photoconductor. In such a case, preparation by applicator coating, spray coating or the like is necessary. In Example 9, the butadiene compound represented by the general formula (4), the styryl compound represented by the general formula (5), or the amine compound represented by the general formula (6) was used as the charge transport material. Not so
The sensitivity was slightly low and exposure adjustment was necessary. Example 10
Then, since the polycarbonate resin B is not mixed,
After the repeated copying of 30,000 sheets, the portion exposed to ozone and NOx deteriorated and some image unevenness occurred, but no scratch was generated on the surface of the photoconductor and the potential characteristics were stable.

[0122]

As described above, according to the present invention, an undercoat layer containing needle-shaped or dendritic titanium oxide particles, and a charge generation layer containing a butyral resin represented by the general formula (1),
By combining with the charge transport layer containing the polycarbonate resin A having the structural unit represented by the general formula (2), matching property between electronic injection level and trap level of each material, carrier mobility of the charge transport material , And good photoreceptor characteristics are obtained, reflecting the superiority of the molecularly dispersed charge transport material based on physical and chemical interactions, excellent sensitivity characteristics and charging characteristics, and sensitivity deterioration during repeated use, It is possible to provide an electrophotographic photosensitive member that has practically sufficient performance with a small decrease in charging potential and a small increase in residual potential.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a multi-layer photosensitive member according to an embodiment of the present invention.

[Explanation of symbols]

1 Conductive support 2 Charge generation material 3 Charge generation layer 4 Charge transport materials 5 Charge transport layer 6 Undercoat layer 7,8 binder resin 20 Photosensitive layer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masaki Hashimoto             22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka             Inside the company (72) Inventor Hiroshi Sugimura             22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka             Inside the company F term (reference) 2H068 AA13 AA44 BB16 BB26 BB52                       CA29

Claims (2)

[Claims] 1. An electrophotographic image obtained by laminating an undercoat layer, a charge generation layer containing a charge generation material and a binder resin, and a charge transport layer containing a charge transport material and a binder resin on a conductive substrate. In the photoreceptor, the undercoat layer contains at least one of acicular and dendritic titanium oxide particles, and the binder resin of the charge generation layer is a butyral represented by the following general formula (1). An electrophotographic photoreceptor comprising a resin, wherein the binder resin of the charge transport layer contains a polymer compound having a structural unit represented by the following general formula (2). [Chemical 1] (In the formula, R ⁰ represents a hydrogen atom, a methyl group or an ethyl group, and j, k, l and m represent an integer.) (Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ⁸
Each has a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms which may have a substituent, a cyclic hydrocarbon group having 4 to 10 carbon atoms which may have a substituent, or a substituent. Represents an optionally substituted aryl group. ) 2. The polymer compound has a viscosity average molecular weight of 3.
The electrophotographic photosensitive member according to claim 1, wherein the electrophotographic photosensitive member is in the range of 50,000 to 70,000.