JPH11344813A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having high wear resistance and capable of maintaining good durability, even when used in such a process as a contact electrification system by incorporating a polycarbonate having a specified chemical structure or its copolymer. SOLUTION: In this electrophotographic photoreceptor obtd. by disposing a photosensitive layer on an electrically conductive substrate, the photosensitive layer contains a polymer having repeating structural units represented by the formula or its copolymer. In the formula, R<1> -R<6> are each H, alkyl, optionally substd. aryl or halogen. However, when all of R<1> , R<3> , R<5> and R<6> are H, R<2> and R<4> are not identical. The figures in the structural formula show the substitution positions of each benzene ring. The photosensitive layer may have monolayer and multilayer structures. In the case of a laminated photoreceptor, the polymer or its copolymer is preferably contained in the outermost layer.

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, and more particularly, to an electrophotographic photosensitive member using a polymer having a specific structure as a binder resin.

[0002]

2. Description of the Related Art In recent years, electrophotographic apparatuses have been widely used in fields such as copiers and laser beam printers because of their advantages of obtaining high-quality images at high speed. Electrophotographic photoreceptors used in these electrophotographic apparatuses are less expensive than electrophotographic photoreceptors using inorganic photoconductive materials such as conventional selenium, selenium-tellurium alloy, selenium-arsenic alloy, and cadmium sulfide. In addition, an electrophotographic photoreceptor using an organic photoconductive material which is excellent in manufacturability, disposability and the like has come to dominate. Above all,
Function-separated type organic photoreceptors, in which a charge generation layer that generates charge by exposure and a charge transport layer that transports the charge, are stacked, provide various characteristics required for electrophotography such as sensitivity, chargeability, and repetition stability. Therefore, many researches and developments have been performed, and as a result, various proposals have been made and put to practical use.

However, organic photoreceptors generally have poorer mechanical strength than inorganic photoreceptors, and are susceptible to abrasion and abrasion when subjected to mechanical external forces such as a cleaning blade, a developing brush, and paper. There is a problem that the life of the photoconductor is short. Furthermore, in recent years, an electrophotographic system using a contact charging system has been adopted from the viewpoint of ecology. However, in this contact charging system, the abrasion of the photoreceptor becomes larger as compared with a normal charging system using a corotron, and as a result, There has been a problem that the sensitivity of the photoreceptor is reduced to cause fogging in a copy image to be obtained, and that the charged potential is lowered to lower the image density. Therefore, development of a surface layer material that forms a photosensitive layer having sufficient durability in an organic photoreceptor has been desired.

A flexible electrophotographic photosensitive member having a photosensitive layer formed on a film such as polyethylene terephthalate having a conductive layer formed by a vapor deposition method or the like is processed into a belt shape and used repeatedly in an electrophotographic apparatus. In addition to this, there is an advantage that the degree of freedom of the shape of the electrophotographic apparatus can be increased. However, there is a demand that the photoconductor used therein must sufficiently follow flexible movement. For example, photoconductors using various polycarbonate resins as a binder resin for the surface layer have been proposed ( JP-A-60-172444, JP-A-62-2473
74, JP-A-63-148263.

However, when a coating film of a photosensitive layer is formed by using a conventionally proposed binder resin, a belt-like electrophotographic photosensitive member having relatively good durability can be obtained, but its mechanical strength is not always required. It cannot be said that it is at a sufficient level, and if used repeatedly for a long time in a belt driving device in a copying machine, there is a problem that cracks are formed in the photosensitive layer and appear as cracks on the copied image. Was.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation in the prior art, and has as its object to solve the above-mentioned problems. That is, the object of the present invention is to have high wear resistance,
An object of the present invention is to provide an electrophotographic photosensitive member that can maintain good durability even when used in a process such as a contact charging system.
Further, another object of the present invention is that the coating film on the photoreceptor surface has a high bending strength, and even when repeatedly used as a belt-shaped photoreceptor, defects such as cracks do not occur in the coating film,
Another object of the present invention is to provide an electrophotographic photoreceptor having high durability and excellent durability without mechanical deterioration.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies on the above-mentioned problems in the electrophotographic photoreceptor, and as a result, a polycarbonate having a specific chemical structure or a copolymer thereof has been used as a binder resin for the photosensitive layer. It has extremely excellent properties regarding the durability related to mechanical strength, and the drum-shaped photoreceptor and the belt-shaped photoreceptor using the same can be used for the photosensitive layer even when used repeatedly in an electrophotographic apparatus for a long time. The inventors have found that mechanical deterioration can be largely eliminated, and have completed the present invention.

That is, the present invention relates to an electrophotographic photoreceptor comprising a photosensitive layer provided on a conductive support, wherein the photosensitive layer has a polymer having a repeating structural unit represented by the following structural formula (I) or a copolymer thereof. It is characterized by containing a polymer.

Embedded image (Wherein, R ^{1 to} R ⁶ are each independently selected from the group consisting of a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group, and a halogen atom.
When R ¹ , R ³ , R ⁵ and R ⁶ are all hydrogen atoms, R ² and R ⁴ are not the same. The numbers in the structural formulas indicate the substitution positions of the benzene ring. )

In the electrophotographic photosensitive member of the present invention, the photosensitive layer may have a single-layer structure (single-layer photosensitive member) or a multilayer structure (laminated photosensitive member). In the case of a laminated photoreceptor, the outermost surface layer preferably contains a polymer having a repeating structural unit represented by the above structural formula (I) or a copolymer thereof. Further, in the laminated photoreceptor, the photosensitive layer comprises at least a charge generation layer and a charge transport layer, and a polymer or a copolymer thereof having a repeating structural unit represented by the above structural formula (I) in the charge transport layer. It is preferred to contain.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. First, the electrophotographic photosensitive member of the present invention will be described. 1 to 7 are schematic sectional views showing the layer structure of the electrophotographic photoreceptor of the present invention. 1 to 4 show a case where the photosensitive layer has a laminated structure. FIG. 1 shows a case where a charge generation layer 1 is provided on a conductive support 3 and a charge transport layer 2 is provided thereon. Is what it is. In FIG. 2, FIG.
Is provided with an undercoat layer 4 on a conductive support 3. In FIG. 3, a protective layer 5 is further provided on the surface of FIG. In FIG. 4, FIG.
Is further provided with both an undercoat layer 4 and a protective layer 5.

FIGS. 5 to 7 show a case where the photosensitive layer has a single-layer structure. FIG. 5 shows a photosensitive layer 6 provided on a conductive support 3. In FIG. 6, an undercoat layer 4 is provided between the conductive support 3 and the photosensitive layer 6. FIG.
In FIG. 5, both the undercoat layer 4 and the protective layer 5 are further provided on the structure shown in FIG. The polymer having a repeating structural unit represented by the above structural formula (I) or a copolymer thereof in the present invention is used for the electrophotographic photoreceptor having any of the layer configurations shown in FIGS. .

Hereinafter, each layer of the electrophotographic photosensitive member according to the present invention will be described in detail. As the conductive support, aluminum, copper, iron, zinc, nickel or other metal drum or sheet, and paper, plastic or glass, aluminum, copper, gold, silver, platinum, palladium, titanium, nickel Chromium steel, stainless steel, copper-deposit metal such as indium, or deposit a conductive metal compound such as indium oxide or tin oxide, laminate metal foil, or carbon black, indium oxide, or tin oxide. A well-known drum-shaped material, a sheet-shaped material, a plate-shaped material, or the like, which is obtained by applying a coating liquid in which antimony oxide powder, metal powder, copper iodide, or the like is dispersed in a binder resin, and performing a conductive treatment is used. Can be When a metal pipe is used as a conductive support, its surface can be used as a raw tube or in advance, mirror cutting, etching, anodic oxidation, rough cutting, centerless grinding,
Although surface treatment such as sand blasting and wet honing may be performed, those subjected to surface roughening treatment on the support surface, when using a coherent light source such as a laser beam,
It is preferable because grain-like density unevenness due to interference light generated in the photoconductor can be prevented.

As the undercoat layer, acetal resin such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacryl resin,
In addition to polymer resin compounds such as acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, and melamine resin, zirconium, Titanium,
It is formed using a known material such as an organometallic compound containing aluminum, manganese, silicon atoms, and the like. These compounds can be used alone or as a mixture or a polycondensate of a plurality of compounds. Above all, when an organometallic compound containing zirconium or silicon is used, it is possible to obtain a compound having good performance such as a low residual potential and a small potential change due to the environment, and a small potential change due to repeated use. Can be

Examples of the silicon compound used for the undercoat layer include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ
-Aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxy Examples include silane. Further, more preferred are vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, and 2- (3,4-epoxycyclohexyl). Ethyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane,
N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane,
Examples include silane coupling agents such as 3-chloropropyltrimethoxysilane.

As the organic zirconium compound, zirconium butoxide, ethyl zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl zirconium butoxide acetoacetate, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate , Zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, zirconium butoxide methacrylate, zirconium butoxide stearate, zirconium butoxide isostearate, and the like are used.

Examples of the organic titanium compound include, for example, tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium Lactate ammonium salt, titanium lactate, titanium lactate ethyl ester, titanium triethanol aminate, polyhydroxytitanium stearate and the like are used, and as the organic aluminum compound, aluminum isopropylate, monobutoxyaluminum diisopropylate, aluminum butyrate , Diethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate) It is.

Furthermore, various organic fine powders or inorganic fine powders can be mixed in the undercoat layer for the purpose of improving electric characteristics and light scattering properties. In particular, organic pigments such as polycyclic quinone pigments having electron transport properties, perylene pigments, azo pigments, etc., white pigments such as titanium oxide, zinc oxide, zinc white, zinc sulfide, lead white, lithopone, alumina, calcium carbonate, sulfuric acid It is preferable to use inorganic pigments, Teflon resin particles, benzoguanamine resin particles, styrene resin particles and the like as extenders such as barium. The particle size of the fine powder to be added is 0.01 to 2 μm. These fine powders are added as needed, and the amount of addition is 10 to 80% by weight, preferably 30 to 70% by weight based on the solid content of the undercoat layer. The thickness of the undercoat layer is preferably in the range of 0.1 to 10 μm. When a fine powder is used for forming the undercoat layer coating liquid, a dispersion treatment is performed by adding the fine powder to a solution in which a resin component is dissolved. In order to disperse the fine powder in the resin, a method such as a roll mill, a ball mill, a vibration ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker can be used.

As described above, the photosensitive layer formed on the undercoat layer may have a single-layer structure or a laminated structure in which a charge generation layer and a charge transport layer are separated in function. In the case of a laminated structure, any of the charge generating layer and the charge transport layer may be arranged in an upper layer. In the electrophotographic photoreceptor of the present invention, a polymer having a repeating structural unit represented by the following structural formula (I) or a copolymer thereof is used as a binder resin for the photosensitive layer. In particular, in the case of a photoconductor having a laminated structure, it is preferable to use such a polymer or a copolymer thereof as a binder resin for the charge transport layer or the surface layer.

[0019]

Embedded image In structural formula (I), R ¹ ~R ⁶ independently of one another are each a hydrogen atom, an alkyl group, but are those selected from the group consisting of an aryl group or a halogen atom or a substituted or unsubstituted, R ^1, When R ³ , R ⁵ and R ⁶ are all hydrogen atoms, R ² and R ⁴ are not the same.

The binder resin used in the present invention includes a homopolymer of a repeating structural unit represented by the above structural formula (I), a copolymer of two or more of those structural units, or a compound represented by the structural formula (I). And a copolymer of a repeating structural unit and another monomer. In the present invention, among the structural units represented by the structural formula (I), a structural unit represented by the following structural formula (II) is preferable.

Embedded image In the structural formula (II), R ¹ ~R ^4, independently of one another, each represent a hydrogen atom, an alkyl group, but are those selected from the group consisting of an aryl group or a halogen atom or a substituted or unsubstituted, R ¹ and When both R ³ are hydrogen atoms, R ² and R ⁴ are not the same.

Further, among the structural units represented by the structural formula (I), a structural unit represented by the following structural formula (III) or (IV) is more preferable.

Embedded image

Embedded image

In the present invention, specific examples of the repeating structural unit represented by the structural formula (I) constituting the polymer used as the binder resin of the photosensitive layer or the copolymer thereof are shown in Tables 1 to 3.
It is shown in Table 4.

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

[0025]

[Table 4]

Next, a synthesis example of a polymer having a repeating structural unit represented by the structural formula (I) used in the present invention will be described. By reacting a bisphenol compound represented by the following general formula (V) with phosgene, a polymer having a repeating structural unit represented by the structural formula (I) can be easily produced.

Embedded image (In the formula, R ^{1 to} R ⁶ have the same meaning as described above.)

Hereinafter, an example of the synthesis of a polymer having a repeating structural unit represented by the structural formula (I) will be described. In a 2 liter reactor, a bisphenol compound represented by the general formula (V) (R ¹ = 2-CH ₃ , R ^{2 to} R ⁶ = H) 0.2 mol, a concentration of 4.7% by weight aqueous sodium hydroxide solution 400 ml and methylene chloride 350 ml were added and phosgene was blown into the vigorously stirred solution at a rate of 400 ml / min for 15 minutes. Keep the reaction temperature at 15 ° C,
40m aqueous sodium hydroxide solution with a concentration of 13.7% by weight
1, trimethylbenzyl ammonium chloride 0.2
g and 0.3 ml of triethylamine were added, and stirring was continued at 23 ° C. for 1 hour to carry out a polycondensation reaction. After the reaction,
The product was diluted with 400 ml of methylene chloride and washed sequentially with 1 liter of water, 0.5 liter of 0.01N hydrochloric acid and 1 liter of water. The resulting organic layer was poured into 5 liters of methyl alcohol to precipitate a white polymer, which was then filtered and dried at 100 ° C. for 12 hours to obtain the corresponding structural unit represented by the structural formula (I) ( Compound No. 1-
A polymer (viscosity average molecular weight: about 40,000) consisting of 1) was obtained. Further, the copolymer having two or more kinds of repeating structural units in the structural formula (I) is produced by mixing and using bisphenol compounds each having a corresponding structure and reacting in the same manner as described above. be able to.

In the present invention, the polymer having a repeating structural unit represented by the structural formula (I) has the object of improving compatibility with a charge transporting material and solubility in a solvent or improving film-forming properties. Is mixed with another resin or copolymerized for use. Examples of the resin that can be used for the mixing or the copolymerization include, for example, different compounds in the structural formula (I), bisphenol (A), bisphenol (Z),
Various polycarbonate resins having bisphenol (C), bisphenol (TP), biphenol, etc., polyester resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polystyrene resins, polyvinyl acetate resins, styrene-butadiene copolymers, vinylidene chloride- Examples include acrylonitrile copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinylcarbazole and the like. The molecular weight of the polymer used in the present invention is appropriately selected depending on film forming conditions such as a film thickness of a photosensitive layer and a solvent, or mechanical properties such as abrasion resistance. And more preferably in the range of 20,000 to 200,000.

In the electrophotographic photoreceptor of the present invention, the photosensitive layer, particularly the charge transport layer, is formed by using a polymer having a repeating structural unit represented by the above structural formula (I) or a copolymer thereof as a binder resin. In the cylindrical photoreceptor serving as the surface layer, it is possible to improve the abrasion resistance of the photoreceptor and reduce surface scratches. In a belt-type photoconductor,
Regardless of whether the above-mentioned polymer or its copolymer used in the present invention is present at any of the upper and lower positions in the photosensitive layer, the mechanical life related to flexibility can be improved. Further, these photoconductors have excellent electrical characteristics and can form high-quality images.

The charge generation layer in the present invention is formed by forming the charge generation substance by vacuum evaporation or by applying a coating liquid in which the charge generation substance is dispersed in an organic solvent and a binder resin. Examples of the charge generating material used in the present invention include amorphous photoconductors such as amorphous selenium, crystalline selenium, selenium-tellurium alloy, selenium-arsenic alloy, other selenium compounds or selenium alloys, zinc oxide, and titanium oxide. Various phthalocyanine pigments such as metal-free phthalocyanine, titanyl phthalocyanine, copper phthalocyanine, tin phthalocyanine, gallium phthalocyanine, squarium,
Examples include various organic pigments and dyes such as an anthrone-based, perylene-based, azo-based, anthraquinone-based, pyrene-based, pyrylium salt, and thiapyrylium salt. In addition, these organic pigments generally have several types of crystal forms, and in particular, phthalocyanine pigments are known to have various crystal types including α-type and β-type, but the desired sensitivity can be obtained. As long as it is a pigment, any of these crystal forms can be used.

In the present invention, a phthalocyanine pigment is used as the charge generating material which can obtain good performance in relation to the polymer used in the photosensitive layer, particularly, the charge transport layer. Examples include the following compounds. Chlor having diffraction peaks at least at positions of 7.4 °, 16.6 °, 25.5 ° and 28.3 ° in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using Cuka radiation. At least 7.5 in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using gallium phthalocyanine and Cuka radiation.
°, 9.9 °, 12.5 °, 16.3 °, 18.6 °,
Bragg angles (2θ ± 0.2) of X-ray diffraction spectra using hydroxygallium phthalocyanine having a diffraction peak at a position of 25.1 ° and 28.1 ° and Cuka radiation.
°), at least 9.5 °, 11.7 °, 1
Titanyl phthalocyanine having diffraction peaks at 5.0 °, 24.1 ° and 27.3 °.

The following are examples of the binder resin used for the charge generation layer. That is, polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene having bisphenol A type, bisphenol Z type or the structure represented by the structural formula (I) Polymer, vinylidene chloride
Acrylonitrile copolymer, vinyl chloride-vinyl acetate-
Maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinylcarbazole and the like can be mentioned. These binder resins may be used alone or
It is possible to use a mixture of species or more. The compounding ratio (weight ratio) of the charge generating material and the binder resin is 10: 1 to 1:
A range of 10 is desirable. The thickness of the charge generation layer is generally 0.01 to 5 μm, preferably 0.05 to 2.0 μm.
It is set in the range of μm. In order to disperse the charge generating material in the resin, a roll mill, a ball mill, a vibrating ball mill, an attritor, a dyno mill, a sand mill, a colloid mill, or the like is used.

Specific examples of the charge transport material used in the charge transport layer include the following. Oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5
-Triphenyl-pyrazoline, 1- [pyridyl-
(2)]-3- (p-Diethylaminostyryl) -5-
Pyrazoline derivatives such as (p-diethylaminostyryl) pyrazoline, triphenylamine, tri (p-methyl)
Phenylamine, N, N-bis (3,4-dimethylphenyl) biphenyl-4-amine, dibenzylaniline,
Aromatic tertiary amino compounds such as 9,9-dimethyl-N, N-di (p-tolyl) fluorenone-2-amine;
Aromatic tertiary diamino compounds such as N'-diphenyl-N, N'-bis (3-methylphenyl)-[1,1-biphenyl] -4,4'-diamine; 3- (4'-dimethylamino) 1,2,4-triazine derivatives such as phenyl) -5,6-di- (4'-methoxyphenyl) -1,2,4-triazine, 4-diethylaminobenzaldehyde-
1,1-diphenylhydrazone, 4-diphenylaminobenzaldehyde-1,1-diphenylhydrazone,
[P- (Diethylamino) phenyl] (1-naphthyl)
Hydrazone derivatives such as phenylhydrazone, quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline,
6-hydroxy-2,3-di (p-methoxyphenyl)
Benzofuran derivatives such as benzofuran, p- (2,2
-Diphenylvinyl) -Hole transport materials such as α-stilbene derivatives such as N, N-diphenylaniline, enamine derivatives, carbazole derivatives such as N-ethylcarbazole, poly-N-vinylcarbazole and derivatives thereof.

Quinone compounds such as chloranil, bromoanil and anthraquinone; tetracyanoquinodimethane compounds; 2,4,7-trinitrofluorenone;
Fluorenone compounds such as 2,4,5,7-tetranitro-9-fluorenone; 2- (4-biphenyl) -5-
(4-t-butylphenyl) -1,3,4-oxadiazole or 2,5-bis (4-naphthyl) -1,3,4-
Oxadiazole, oxadiazole compounds such as 2,5-bis (4-diethylaminophenyl) -1,3,4-oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5′- Examples thereof include an electron transporting substance such as a diphenoquinone compound such as tetra-t-butyldiphenoquinone or a polymer having a group consisting of the above compound in a main chain or a side chain. These charge transport materials can be used alone or in combination of two or more.

In the present invention, in the context of a polymer having a repeating structural unit represented by the above structural formula (I) or a copolymer thereof used as a binder resin in the charge transport layer,
As a charge transporting material that can obtain particularly excellent performance, a benzidine compound represented by the following general formula (VI) or a triarylamine compound represented by the following general formula (VII) can be given.

The benzidine compound used in the present invention is represented by the following general formula (VI).

Embedded image (Wherein, R ⁶¹ and R ⁶² may be the same or different and each represent a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom; R ^{63 to} R ⁶⁶ may be the same or different; , An alkyl group, an alkoxy group, a halogen atom or a substituted amino group. K to n are each 1 or 2.) Specific examples of the benzidine-based compound represented by the general formula (VI) include: The results are shown in Tables 5 to 7.

[Table 5]

[0037]

[Table 6]

[0038]

[Table 7]

The triarylamine compound used in the present invention is represented by the following general formula (VII).

Embedded image (Wherein, R ⁷¹ and R ⁷² may be the same or different, a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, p and q is 1 or 2. Further, R ⁷³
Is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or 6 to
Represents 12 aryl groups. )

Tables 8 and 9 show specific examples of the triarylamine compound represented by the general formula (VII).

[Table 8]

[0041]

[Table 9]

The electrophotographic photoreceptor of the present invention contains an antioxidant in the photosensitive layer for preventing deterioration of the photoreceptor due to ozone or oxidizing gas generated in the electrophotographic apparatus, or light or heat. Additives such as an agent and a heat stabilizer can be added. As the antioxidant, for example, hindered phenol-based, hindered amine-based, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and derivatives thereof, and organic sulfur-based or organic phosphorus-based compounds are used. Specific examples of the phenolic antioxidant include 2,6-di-t-butyl-4-methylphenol, styrenated phenol, and n-octadecyl-3- (3 ', 5'-di-t.
-Butyl-4'-hydroxyphenyl) -propionate, 2,2'-methylene-bis (4-methyl-6-t-
Butylphenol), 2-t-butyl-6- (3'-t
-Butyl-5'-methyl-2'-hydroxybenzyl)
-4-methylphenyl acrylate, 4,4'-butylidene-bis (3-methyl-6-t-butylphenol), 4,4'-thio-bis (3-methyl-6-t-butylphenol), 1,3 , 5-Tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, tetrakis [methylene-3- (3 ',
5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, 3,9-bis [2- {3- (3
-T-butyl-4-hydroxy-5-methylphenyl)
Propionyloxy}]-1,1-dimethylethyl]-
2,4,8,10-tetraoxaspiro [5,5] undecane and the like.

Examples of hindered amine compounds include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate and bis (1,2,2,6,6-pentamethyl-4).
-Piperidyl) sebacate, 1- [2- {3- (3,5
-Di-t-butyl-4-hydroxyphenyl) propionyloxy {ethyl] -4- {3- (3,5-di-t-
Butyl-4-hydroxyphenyl) propionyloxy {-2,2,6,6-tetramethylpiperidine, 8-
Benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4-dione, 4-benzoyloxy-2,2,
6,6-tetramethylpiperidine, dimethyl succinate-
1- (2-hydroxyethyl) -4-hydroxy-2,
2,6,6-tetramethylpiperidine polycondensate, poly [{6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diimyl}
｛(2,2,6,6-tetramethyl-4-piperidyl)
Imino {hexamethylene} (2,3,6,6-tetramethyl-4-piperidyl) imino}], 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalone (1,2,2,6,6-pentamethyl-4-biperidyl) acid, N, N'-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-
N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate and the like.

Examples of the organic sulfur antioxidants include dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearyl-
3,3′-thiodipropionate, pentaerythritol-tetrakis (β-lauryl-thiopropionate), ditridecyl-3,3′-thiodipropionate, 2-mercaptobenzimidazole, and the like,
As organophosphorus antioxidants, trisnonylphenylphosphite, triphenylphosphite, tris (2,
4-di-t-butylphenyl) -phosphite and the like. Among them, the organic sulfur-based and organic phosphorus-based antioxidants are called secondary antioxidants, and have a synergistic effect when used in combination with a primary antioxidant such as a phenolic or amine compound. Is obtained.

Examples of the light stabilizer include benzophenone, benzotriazole, dithiocarbamate,
Derivatives such as tetramethylpiperidine are used. As the benzophenone-based light stabilizer, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-
Octoxybenzophenone, 2,2'-di-hydroxy-4-methoxybenzophenone, and the like. Benzotriazole-based light stabilizers include 2- (2'-hydroxy-5'-methylphenyl) benzotriazole,
-[2'-hydroxy-3 '-(3 ", 4", 5 ",
6 "-tetrahydrophthalimido-methyl) -5'-methylphenyl] benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-
5-chlorobenzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5
Chlorobenzotriazole, 2- (2'-hydroxy-
3 ', 5'-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole, 2- (2'-hydroxy-
3 ', 5'-di-t-amylphenyl) benzotriazole and the like. Other examples include 2,4-di-t-butylphenyl-3 ', 5'-di-t-butyl-4'-hydroxybenzoate, nickel dibutyl-dithiocarbamate, and the like.

To the electrophotographic photoreceptor of the present invention, one or more electron-accepting substances are added, if necessary, for the purpose of improving the sensitivity of the photoreceptor, reducing the residual potential, and reducing fatigue upon repeated use. be able to. Examples of the electron-accepting substance that can be used for the photoreceptor include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrabromophthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, and o-diamine. Examples thereof include nitrobenzene, m-dinitrobenzene, chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, and phthalic acid. Among these, fluorenone compounds, quinone compounds,
A benzene derivative having a halogen atom such as Cl or an electron-withdrawing substituent such as CN or NO ₂ is particularly preferred.

The charge transport layer is coated with a coating solution obtained by dissolving the above-described charge transport material and a polymer having a repeating structural unit represented by the structural formula (I) or a copolymer thereof in an appropriate solvent, and drying the coating solution. It can be formed by performing. Typical examples of the solvent used for forming the charge transport layer include aromatic hydrocarbons such as benzene, toluene and chlorobenzene, ketones such as acetone and 2-butanone, methylene chloride, chloroform, and ethylene chloride. And cyclic or linear ethers such as tetrahydrofuran, dioxane, ethylene glycol, diethyl ether and the like, or a mixed solvent thereof. Also, as a coating liquid, a trace amount of silicone oil can be added as a leveling agent for improving the smoothness of the coating film. The compounding ratio of the charge transport material and the polymer is 1
0: 1 to 1: 5 is preferred. The thickness of the charge transport layer is
Generally, it is set in the range of 5 to 50 μm, preferably 10 to 30 μm. Further, the application of the coating solution can be performed by a dip coating method, a ring coating method, a spray coating method, a bead coating method, a blade coating method, a roller coating method, or the like, depending on the shape and application of the photoreceptor. Drying is preferably performed by heat drying after touch drying at room temperature. The heat drying is desirably performed at a temperature of 30 to 200 ° C. for a time in a range of 5 minutes to 2 hours.

In the electrophotographic photosensitive member of the present invention, a surface protective layer can be formed on the photosensitive layer, if necessary.
As the surface protective layer, there is an insulating resin protective layer or a low resistance protective layer obtained by adding a resistance adjuster to the insulating resin. In the case of the low-resistance protective layer, for example, a layer in which conductive fine particles are dispersed in an insulating resin is preferable. The conductive fine particles have an electric resistance of 10 ⁹ Ω · cm or less, and are white, gray, Or, the average particle size of exhibiting bluish white is 0.3 μm or less,
Fine particles of preferably 0.1 μm or less are suitable, for example, molybdenum oxide, tungsten oxide, antimony oxide, tin oxide, titanium oxide, indium oxide, a solid solution carrier of tin oxide and antimony or antimony oxide or a mixture thereof, What mixed or coated these metal oxides in a single particle is mentioned. Among them, tin oxide, and a solid solution of tin oxide and antimony or antimony oxide are preferably used because the electric resistance can be appropriately adjusted and the protective layer can be made substantially transparent. JP-A-57-30847, JP-A-57-30847
-128344). Examples of the insulating resin include condensation resins such as polyamide, polyurethane, polyester, epoxy resin, polyketone, and polycarbonate, and vinyl polymers such as polyvinylketone, polystyrene, and polyacrylamide.

The electrophotographic photoreceptor of the present invention can be used in electrophotographic devices such as light lens type copiers, laser beam printers emitting near-infrared light or visible light, digital copiers, LED printers, and laser facsimile machines. it can. The photoreceptor can be used in combination with a one-component or two-component regular developer or a reversal developer. In addition, the photoreceptor has good electric characteristics with little current leakage even in a contact charging system using a charging roller or a charging brush.

Further, in the laminated type photoreceptor, the charging polarity of the photoreceptor differs depending on the charge transporting polarity of the charge transporting material. That is, when the hole transport material is used, the photoconductor is used as negatively charged, while when the electron transport material is used, the photoconductor is used as positively charged.
When both are mixed, a photoreceptor having both charging polarities is possible.

The electrophotographic photoreceptor of the present invention can be used in any of a corona discharge system and a contact charging system, and is particularly effective for a contact charging system. . Hereinafter, an electrophotographic apparatus using the electrophotographic photosensitive member of the present invention will be described.

FIG. 8 is a schematic view of an electrophotographic apparatus using the electrophotographic photosensitive member of the present invention. A photosensitive member 7 is provided with a charging member 8 of a corona discharge type for charging. A voltage is supplied to the charging member 8 from a power supply 9.
Around the photoreceptor, an image input device 10, a developing device 11,
A transfer device 12, a cleaning device 13, and a static eliminator 14 are provided. Reference numeral 15 denotes a fixing device. FIG.
1 is a schematic view of a contact charging type electrophotographic apparatus using the electrophotographic photoreceptor of the present invention. 8 is the same as FIG. 8 except that a contact charging member 16 is provided in contact with the photoconductor 7. In this contact type electrophotographic apparatus, the static eliminator 14
Some are not provided.

[0053]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. Example 1 ED tube aluminum (30 mmφ) was used for the conductive support.
The center line average roughness Ra = 0.0 was obtained by a liquid honing method using alumina spherical fine powder (D ₅₀ = 30 μm).
A material having a surface roughness of 18 μm was used. On the aluminum support, 4 parts by weight of a polyvinyl butyral resin (Eslec BM-S, manufactured by Sekisui Chemical Co., Ltd.) was dissolved.
-Organic zirconium compound (acetylacetone zirconium butyrate) 3 in 170 parts by weight of butyl alcohol
0 parts by weight and 3 parts by weight of a mixture of organic silane compounds (γ-aminopropyltrimethoxysilane) were applied by dip coating using a coating liquid for forming an undercoat layer obtained by mixing and stirring. A curing treatment was performed for a long time to form an undercoat layer having a thickness of 1.2 μm. Next, the Bragg angle (2θ ±) of the X-ray diffraction spectrum using Cukα ray
0.2 °) at 7.4 °, 16.6 °, 25.5
°, 28.3 °, chlorogallium phthalocyanine having a clear X-ray diffraction peak at 3 parts by weight, vinyl chloride-
Vinyl acetate copolymer (VMCH, manufactured by Nippon Unicar) 2
Parts by weight of a mixture consisting of 180 parts by weight of butyl acetate and 180 parts by weight of butyl acetate was dispersed by a sand mill for 4 hours.
The undercoat layer was applied by a dip coating method and dried to form a 0.2 μm-thick charge generation layer.

Next, N, N'- shown in Compound No. 6-1
Diphenyl-N, N'-bis (3-methylphenyl)-
6 parts by weight of a polymer (viscosity average molecular weight: about 40,000) consisting of 4 parts by weight of [1,1'-biphenyl] -4,4'-diamine and a repeating structural unit represented by Compound No. 1-9 as a binder resin , 80 parts by weight of tetrahydrofuran and 0.2 parts by weight of 2,6-di-t-butyl-4-methylphenol were added and dissolved, and the mixture was coated on the charge generation layer using a coating liquid obtained. This was dried at 120 ° C. for 40 minutes to form a charge transport layer having a thickness of 25 μm, thereby producing an electrophotographic photosensitive member. The obtained electrophotographic photosensitive member was converted to a printer having a contact charging system (PC-PR10).
00 / 4R (manufactured by NEC Corporation) to perform a print test of 50,000 sheets, check the image quality after printing 10,000 sheets, and to measure the residual potential, charging potential and abrasion of the photoconductor after printing 50,000 sheets. The amount was measured and evaluated.

Examples 2 to 4 The binder resins for the charge transporting layer used in Example 1 were identified by the respective compound numbers (1-60, 1-88 and 1-
An electrophotographic photoreceptor was produced in exactly the same manner as in Example 1, except that the polymer (viscosity average molecular weight: about 40,000) consisting of the repeating structural unit of 95) was used. Using each of the obtained electrophotographic photoreceptors, a print test was performed in the same manner as in Example 1 to measure and evaluate.

Comparative Examples 1 to 3 Electrophotography was performed in exactly the same manner as in Example 1 except that the binder resin of the charge transport layer used in Example 1 was replaced with each of the bisphenol-type polycarbonate resins shown in Table 10. A photoreceptor was produced. Using each of the obtained electrophotographic photoreceptors, a print test was performed in the same manner as in Example 1 to measure and evaluate.

Table 10 shows the results obtained in Examples 1 to 4 and Comparative Examples 1 to 3.

[Table 10]

The photosensitive members obtained in Examples 1 to 4 did not show any image quality abnormality caused by leak discharge of the photosensitive members even when a print test was performed using a printer of a type in which the photosensitive members were charged by a contact charging device. Was. In addition, these photoreceptors had stable electrical characteristics with little abrasion and no decrease in chargeability or increase in residual potential. On the other hand, in the photoconductors obtained in Comparative Examples 1 to 3, the abrasion was large, the dark decay increased, the chargeability was reduced, and fogging was observed in the low density portion. Also, in these photoconductors,
There was a current leak from the contact charging device in a portion where the film thickness was reduced due to abrasion, and it was necessary to repair the leaked portion with an insulating material before running. Further, an image quality defect occurred in the leak portion.

Example 5 A conductive support was provided on a surface of an aluminum substrate (84 mmφ) with a center line average roughness Ra = 50 by a liquid honing method.
A material having a surface roughness of 0.18 μm was used. On the aluminum substrate, 16 parts by weight of a polyvinyl butyral resin (Eslec BM-S, manufactured by Sekisui Chemical Co., Ltd.) and 550 parts by weight of cyclohexanone were mixed and stirred.
5, Dainippon Ink and Chemicals Inc.) 8 parts by weight are added and stirred,
Further, 60 parts by weight of a titanium oxide pigment was added to the mixed solution, and the mixture was dispersed in a sand grind mill for 5 hours using a coating solution obtained. The mixture was cured at 170 ° C. for 1 hour to give a film thickness of 4 μm. Was formed. next,
9.5 °, 11.7 °, 1 in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using Cukα ray
15 parts by weight of titanyl phthalocyanine having clear X-ray diffraction peaks at 5.0 °, 24.1 ° and 27.3 °, polyvinyl butyral resin (Eslec BM-S,
Sekisui Chemical Co., Ltd.) 10 parts by weight and n-butyl alcohol 3
A coating solution obtained by dispersing a mixture consisting of 00 parts by weight in a sand grind mill for 4 hours was coated on the undercoat layer, and dried to form a 0.2 μm-thick charge generation layer. did.

Next, N, N- shown in Compound No. 7-33
A polymer comprising 4 parts by weight of bis (3,4-dimethylphenyl) biphenyl-4-amine and a repeating structural unit of Compound No. 1-9 as a binder resin (viscosity average molecular weight of about 4
Ten thousand parts by weight, 80 parts by weight of chlorobenzene was added to and dissolved in 80 parts by weight, and the solution was applied onto the charge generating layer using a coating solution obtained by drying, and dried to form a charge transporting layer having a thickness of 27 μm. By forming, an electrophotographic photoreceptor was produced. The obtained electrophotographic photoreceptor was mounted on a color copier (Acolor-635, manufactured by Fuji Xerox Co., Ltd.) having an intermediate transfer drum system, and a print test was performed by adjusting the amount of light.
The image quality after printing 5,000 sheets was evaluated.

Examples 6 to 8 The binder resins for the charge transporting layer used in Example 5 were identified by the respective compound numbers (1-60, 1-88 and 1-
95) An electrophotographic photoreceptor was produced in exactly the same manner as in Example 5, except that the polymer having a repeating structural unit (viscosity average molecular weight: about 40,000) was used. Using the obtained electrophotographic photosensitive member, a print test was performed in the same manner as in Example 5 to evaluate the image quality.

Comparative Examples 4 to 6 Electrons were prepared in the same manner as in Example 5 except that bisphenol-type polycarbonate resins shown in Table 11 were used instead of the binder resin of the charge transport layer used in Example 5. A photoreceptor was prepared. Using each of the obtained electrophotographic photosensitive members, a print test was performed in the same manner as in Example 5 to evaluate the image quality.

Example 9 A copolymer (molecular weight: about 40,000) of compound No. 1-88 and bisphenol A type polycarbonate (molar ratio: 60:40) was used in place of the binder resin of the charge transport layer used in Example 5.
An electrophotographic photoreceptor was produced in exactly the same manner as in Example 5 except that the above was replaced with Using the obtained electrophotographic photosensitive member, a print test was performed in the same manner as in Example 5 to evaluate the image quality.

Table 11 shows the results obtained in Examples 5 to 9 and Comparative Examples 4 and 6.

[Table 11] When the photoreceptors obtained in Examples 5 to 9 were used, no fogging occurred, and the occurrence of black spots was small, and good image quality was obtained. On the other hand, the photoreceptors using the polycarbonate resins obtained in Comparative Examples 4 to 6 were fogged, black spots were frequently generated, and abnormal image quality was observed.

Examples 10 to 11 A conductive support having a metallized aluminum film on the surface of a polyethylene terephthalate film (Metal Me,
A coating liquid consisting of 10 parts by weight of a polyamide resin, 150 parts by weight of methyl alcohol and 40 parts by weight of water was applied onto the coating solution and dried to form a subbing layer having a thickness of 1 μm. Next, 7.5 in the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using Cukα ray.
°, 9.9 °, 12.5 °, 16.3 °, 18.6 °,
9 parts by weight of hydroxygallium phthalocyanine having diffraction peaks at positions of 25.1 ° and 28.1 °, polyvinyl butyral resin (Eslec BM-1, manufactured by Sekisui Chemical Co., Ltd.)
A mixture of 2 parts by weight and 30 parts by weight of n-butyl alcohol was placed in a ball mill pot, and milled for 60 hours using SUS stainless steel balls (1/8 inch φ) as a mill member, and then 30 parts by weight of n-butyl alcohol. Part was added and diluted, and the coating solution obtained by stirring this was
Coated on the undercoat layer and dried to a thickness of 0.3 μm
Was formed.

Next, N, N'-diphenyl-N, N'-bis (3-methylphenyl)-shown in Compound Example 6-1 was used.
Polymer (viscosity) consisting of 4 parts by weight of [1,1'-biphenyl] -4,4'-diamine and a repeating unit of each compound number (1-88, 1-95) shown in Table 12 as a binder resin 6 parts by weight of an average molecular weight of about 40,000) and 60 parts by weight of methylene chloride are dissolved and applied to the above-mentioned charge generating layer using a coating solution obtained by drying. An electrophotographic photosensitive member was prepared by forming a transport layer. The coating film of the photosensitive layer of the obtained electrophotographic photosensitive member was peeled off from the conductive substrate, and a bending repetition test was performed up to 5000 times using a bending strength tester. Further, the electrophotographic photosensitive member was processed into a belt shape, and mounted on a copying machine (Vision 800, manufactured by Fuji Xerox Co., Ltd.) having a belt rotation driving device, and a copy running test was performed up to 100,000 cycles. Table 12 shows the obtained results.

Comparative Examples 7 and 8 The procedure of Example 10 was repeated, except that the bisphenol type polycarbonate resin shown in Table 12 was used instead of the binder resin of the charge transport layer used in Example 10. An electrophotographic photoreceptor was prepared and evaluated in the same manner. Table 12 shows the obtained results.

[0068]

[Table 12] Those using the photoreceptor of Example 10 or 11 did not break even after the bending test, and good image quality was obtained even after the copy running test. On the contrary,
The photoconductor using the photoconductor of the comparative example was broken during the bending test, and many failures such as white spots caused by cracks occurred after the copy running test.

[0069]

According to the present invention, a polymer having a repeating structural unit represented by the above structural formula (I) or a copolymer thereof is used as a binder resin for the photosensitive layer. Has high abrasion resistance and bending strength, and is excellent in electrical characteristics and obtained image quality even after repeated use. Therefore, the electrophotographic photoreceptor of the present invention
Even when used in a high-speed copying machine, it exhibits good electrophotographic properties, and when used in a belt-like form, does not cause cracks or the like in the photosensitive layer and has high durability. Further, by using the electrophotographic photoreceptor of the present invention, a high-speed and stable high-quality image can be obtained for a long period of time.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a layer configuration of an example of a laminated electrophotographic photosensitive member according to the present invention.

FIG. 2 is a schematic cross-sectional view illustrating a layer configuration of another example of the laminated electrophotographic photosensitive member according to the invention.

FIG. 3 is a schematic cross-sectional view illustrating a layer configuration of another example of the laminated electrophotographic photosensitive member according to the invention.

FIG. 4 is a schematic cross-sectional view illustrating a layer configuration of another example of a laminated electrophotographic photosensitive member according to the present invention.

FIG. 5 is a schematic cross-sectional view illustrating a layer configuration of another example of the single-layer electrophotographic photosensitive member according to the invention.

FIG. 6 is a schematic cross-sectional view illustrating a layer configuration of another example of the single-layer type electrophotographic photosensitive member according to the invention.

FIG. 7 is a schematic cross-sectional view illustrating a layer configuration of another example of the single-layer electrophotographic photosensitive member according to the invention.

FIG. 8 is a schematic view of an example of an electrophotographic apparatus used in the present invention.

FIG. 9 is a schematic view of a contact charging type electrophotographic apparatus used in the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Charge generation layer, 2 ... Charge transport layer, 3 ... Conductive support,
4 undercoat layer, 5 protective layer, 6 photosensitive layer, 7 photoconductor,
8: Corona discharge type charging member, 9: Power supply, 10: Image input device, 11: Developing device, 12: Transfer device, 13:
Cleaning device, 14: static eliminator, 15: fixing device, 1
6 Member for contact charging.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kenji Yao 1600 Takematsu, Minamiashigara, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (72) Inventor Ichiro Takekawa 1600 Takematsu, Minamiashigara City, Kanagawa Prefecture Inside Fuji Xerox Co.

Claims (6)

[Claims] 1. An electrophotographic photoreceptor comprising a photosensitive layer provided on a conductive support, wherein the photosensitive layer contains a polymer having a repeating structural unit represented by the following structural formula (I) or a copolymer thereof. An electrophotographic photoreceptor characterized in that: Embedded image (Wherein, R ^{1 to} R ⁶ are each independently selected from the group consisting of a hydrogen atom, an alkyl group, a substituted or unsubstituted aryl group, and a halogen atom.
When R ¹ , R ³ , R ⁵ and R ⁶ are all hydrogen atoms, R ² and R ⁴ are not the same. ) 2. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer has a single-layer structure. 3. The photosensitive layer has a multilayer structure of at least two layers, and contains, in its outermost surface layer, a polymer having a repeating structural unit represented by the structural formula (I) or a copolymer thereof. The electrophotographic photoreceptor according to claim 1, wherein 4. The photosensitive layer comprises at least a charge generating layer and a charge transporting layer, wherein the charge transporting layer has the structural formula (I)
4. The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor contains a polymer having a repeating structural unit represented by the formula or a copolymer thereof. 5. The electrophotograph according to claim 1, wherein the repeating structural unit represented by the structural formula (I) is represented by the following structural formula (II). Photoconductor. Embedded image (Wherein, R ¹ to R ⁴ are, independently of one another, each a hydrogen atom, an alkyl group, selected from the group consisting of an aryl group or a halogen atom substituted or unsubstituted. However, R ¹
R ² and R ⁴ are not the same when R ³ and R ³ are both hydrogen atoms. ) 6. The method according to claim 1, wherein the repeating structural unit represented by the structural formula (I) is represented by the following structural formula (III) or (IV). 13. The electrophotographic photoreceptor according to item 6. Embedded image Embedded image