JPH1020527A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow an electrophotographic photoreceptor to exhibit superior mechanical characteristics and electrophotographic characteristics independently of the process speed of an electrophotographic device by incorporating a specified electric charge transferring agent and a specified polycarbonate copolymer into the photosensitive layer. SOLUTION: A triphenylamine compd. represented by formula I is used as an electric charge transferring agent and a polycarbonate copolymer consisting of repeating units represented by formulae II, III is used as a bonding resin. In the formulae, each of R1 -R5 is H or aryl which may have halogen, etc., two of R1 -R4 may bond to each other to form a ring, (a) is 0 or 1, each of X and Y is -CR6 R7 -, 5-8C 1,1-cycloalkylene, 2-12C α,ω-alkylene, a single bond, -O-, -COn, -S-, -SO- or -SO2 -, each of R8 and R9 is H, halogen, etc., and each of (b) and (c) is an integer of 0-4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic photosensitive member, and more particularly to an electrophotographic photosensitive member using an organic photoconductive material.

[0002]

2. Description of the Related Art Generally, selenium (Se), cadmium sulfide (CdS), zinc oxide (ZnO), amorphous silicon (a-Si)
However, a photoreceptor using such an inorganic material is charged in a dark place by, for example, a charging roller, and then subjected to image exposure to selectively remove charges only in an exposed portion, thereby reducing static electricity. It is used for forming an electrostatic latent image and visualizing it with a developer to form an image. The basic characteristics required for such an electrophotographic photoreceptor include that it can be charged to an appropriate potential in a dark place, that it has a function of eliminating surface charges by light irradiation, and the like. Each has its strengths and weaknesses. For example, selenium (Se) sufficiently satisfies the above characteristics,
It is difficult to process it into a film without flexibility.
Since it is sensitive to heat and mechanical shocks, it has drawbacks such as careful handling. Furthermore, amorphous silicon (a-S
i) has the disadvantage that the manufacturing conditions are difficult and the manufacturing cost is high.

Therefore, in recent years, an organic photoreceptor containing a phthalocyanine or azo compound as a charge generating agent and a hydrazone compound or a butadiene compound as a charge transfer agent together with a binder resin has become mainstream.

[0004]

However, in recent years,
2. Description of the Related Art In an electrophotographic apparatus, in particular, a printer using an electrophotographic method, it is desired to increase a printing speed (process speed), increase resolution, and reduce the size. For this reason, as the characteristics of the material for the electrophotographic photoreceptor, it is required that the mobility of the charge transfer agent is particularly high and the photosensitivity is high. However, since the mobility and light sensitivity of the conventionally used charge transfer agents are not sufficient, the current situation is that they cannot cope with an increase in printing speed and an increase in resolution.

In addition, various processes of the electrophotographic apparatus include a process of contacting the electrophotographic photosensitive member, and the surface of the photosensitive member is worn by friction with the electrophotographic photosensitive member. Since it is easily scratched, there are drawbacks such as uneven density and streaks in the printed image. These are especially fatal in devices that are becoming faster.

On the other hand, as the size of the electrophotographic apparatus has been reduced, the diameter of the electrophotographic photosensitive member has been steadily reduced. When the diameter of the electrophotographic photoreceptor is reduced, the number of rotations of the electrophotographic photoreceptor per print sheet increases, so that the mechanical properties of the electrophotographic photoreceptor are required to be further improved.

Therefore, in recent years, an electrophotographic photoreceptor using a triphenylamine derivative as a charge transfer agent has been devised in order to deal with such a problem (for example, Japanese Patent Application Laid-Open No.
According to this electrophotographic photoreceptor, good mobility and light sensitivity can be obtained. However, such an electrophotographic photoreceptor has a disadvantage that the charge retention on the surface of the photosensitive layer, that is, the dark decay is inferior. In addition, when the photosensitive layer is used for a long period of time, the photosensitive layer may be damaged due to a decrease in film thickness, and a streak-like defect may occur in a printed image.

On the other hand, in recent years, electrophotographic devices having a relatively slow process speed for the purpose of reducing the price of the devices have been rapidly spreading. However, when the above-described high-speed electrophotographic photosensitive member is attached to such an apparatus and printing is performed, fog due to low dark attenuation may occur in an initial image in some cases. For this reason, in the case of the conventional technology, the photoconductor material must be changed in accordance with the process speed of the electrophotographic apparatus, which causes a problem such as an increase in manufacturing cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and an electrophotographic apparatus capable of exhibiting excellent mechanical characteristics and electrophotographic characteristics regardless of the process speed of an electrophotographic apparatus. It is intended to provide a photoreceptor.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, an electrophotography in which a specific charge transfer agent and a specific polycarbonate copolymer are contained in a photosensitive layer. It has been found that the photoreceptor has an excellent charge retention rate on the surface of the photosensitive layer and can maintain excellent mechanical strength and electrophotographic properties over a long period of time, and has completed the present invention.

[0011] The present invention has been made based on such knowledge, and the invention according to claim 1 provides a photosensitive layer containing at least a charge generating agent, a charge transfer agent and a binder resin on a conductive support. In the formed electrophotographic photoreceptor, a triphenylamine compound represented by the general formula (1) is used as the charge transfer agent, and a binder represented by the general formulas (2) and (3) is used as the binder resin. Characterized by using a polycarbonate copolymer comprising a repeating unit to be used.

[0012]

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[Wherein, R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ may be the same or different and each represents a hydrogen atom, a halogen atom, a lower alkyl group, an alkoxy group, or a substituent. It represents an aryl group which may be present, or R ₁ , R ₂ and R ₃ , R ₄ may be bonded to each other to form a ring, and a represents 0 or 1. ]

[0014]

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[0015] wherein, X is -CR ₆ R ₇ - (where, R ₆ and R ₇ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, trifluoromethyl group or a C6-12
Represents an aryl group. ), A C1-C8 1,1-cycloalkylene group, a C2-C12 α, ω-alkylene group, a single bond, -O-, -CO-, -S-, -SO- or -SO _2- is shown. Here, the term “single bond” refers to a case where carbon atoms of a benzene ring are directly covalently bonded, and has the same meaning hereinafter.

[0016]

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Wherein R ₈ and R ₉ each independently represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms, b and c each independently represent an integer of 0 to 4, Y has the same meaning as X in the general formula (2). However,
X and Y may be the same or different. ]

The invention of claim 2 is the invention of claim 1, wherein oxytitanium phthalocyanine is used as a charge generating agent.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the electrophotographic photosensitive member according to the present invention will be described in detail.

As the conductive support used in the electrophotographic photoreceptor of the present invention, various types such as known ones can be used. Specifically, for example, aluminum, anodized aluminum, Nickel, copper, stainless steel, brass, or the like, or plastic, a material obtained by depositing or plating a metal such as aluminum, copper, or nickel on the surface of a plastic can be used. Also,
Regarding the shape of the electrophotographic photosensitive member, a drum shape, a plate shape, a sheet shape, and a belt shape can be used.

As the photosensitive layer, a laminated type in which a charge generating layer and a charge transporting layer are sequentially laminated, an inverse laminated type in which a charge transporting layer and a charge generating layer are sequentially laminated, and a single layer containing a charge generating agent and a charge transporting agent. A single-layer type or the like can be used.

As the charge generating agent, various types such as known ones can be used. Specifically, for example, phthalocyanine type, monoazo type, disazo type, trisazo type, tetrakisazo type, polyazo type, polyazo type, etc. Use organic pigments or dyes such as cyclic quinone, indigo, perylene, benzimidazole, selenium alloys such as selenium, selenium-arsenic, selenium-tellurium, selenium-tellurium-arsenic, and inorganic materials such as a-Si can do.

Among them, oxytitanium phthalocyanine having titanium as a central metal is preferable because it exhibits high sensitivity in the vicinity of the wavelength of 600 nm to 800 nm which is the wavelength of a semiconductor laser or LED which is often used as an exposure light source of a printer.

It is known that this oxytitanium phthalocyanine has different characteristics depending on the crystal system.

In the present invention, it is particularly preferable to use oxytitanium phthalocyanine having the following crystal system. (A) 7.3 °, 9.3 °, 10.6 °, 13.2 °,
15.1 °, 15.7 °, 16.1 °, 20.8 °, 2
Those showing strong diffraction peaks at 3.3 °, 26.3 ° and 27.1 °, and having the strongest diffraction peak at 26.3 °. (B) 9.3 °, 10.6 °, 13.2 °, 15.1
°, 15.7 °, 16.1 °, 20.8 °, 23.3
°, 26.3 °, and 27.1 ° show strong diffraction peaks,
And the one having the strongest diffraction peak at 26.3 °. (C) Strong diffraction peaks at 13.6 °, 24.1 ° and 27.3 °, and the strongest 27.3 ° diffraction peak.

When the electrophotographic photoreceptor of the present invention is used in a copying machine, an azo pigment represented by the following general formula (4) is particularly preferred as a charge generating agent.

[0027]

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[Wherein R ₁₀ is a hydrogen atom, a halogen atom,
Represents an alkyl group or an alkoxy group, and R ₁₀ is -CON
HR ₁₁ or —CONNH ＝ CH—R ₁₁ is represented. (However, R ₁₁ represents an aromatic carbocyclic group or an aromatic heterocyclic group which may have a substituent.)] Further, Table 1 shows preferable combinations of R ₁₀ and R ₁₁ .

[0029]

[Table 1]

As a method for forming the charge generation layer, various methods such as a known method can be used. A coating solution in which a charge generation agent is dispersed or dissolved in a suitable solvent together with a binder resin is prepared by a predetermined method. A method of applying and drying on an underlayer can be used.

Further, the charge generation layer can be formed by vacuum-depositing a charge generation agent.

The binder resin in the charge generation layer is not particularly limited, and various resins such as known resins can be used. Specifically, for example, polystyrene, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate, etc. Thermosetting resins such as polymers, polyvinyl acetal, alkyd resins, acrylic resins, polyacrylonitrile, polycarbonate, polyamide, polyketone, polyacrylamide, and butyral resins can be used.

Incidentally, as the binder resin in the charge generation layer, a polycarbonate copolymer comprising a repeating unit represented by the general formula (2) or (3) can also be used.

It is effective to use a triphenylamine compound represented by the general formula (1) as the charge transfer agent.

In this case, R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ may be the same or different and have a hydrogen atom, a halogen atom, a lower alkyl group, an alkoxy group, or a substituent. The lower alkyl group includes an alkyl group having 1 to 4 carbon atoms, such as a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. Or an ethyl group is preferred. Examples of the alkoxy group include an alkoxy group having 1 to 4 carbon atoms, such as a methoxy group, an ethoxy group, a propoxy group and a butoxy group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like.

The aryl group which may have a substituent includes a phenyl group, a p-tolyl group, 2,4
A phenyl group substituted with a lower alkyl group such as -dimethylphenyl group; a phenyl group substituted with a lower alkoxy group such as p-methoxyphenyl group; and a phenyl group substituted with a halogen atom such as p-chlorophenyl group.

Further, R ₁ and R ₂ and R ₃ and R ₄ may be bonded to each other to form a ring, and examples thereof include a substituent forming a 5- to 7-membered ring.

In addition to the compound represented by the general formula (1), various types of electron donating substances or electron accepting substances such as known substances may be added to the charge transfer agent alone or in combination of two or more.

Examples of the electron donating substance include polyvinyl carbazole, halogenated polyvinyl carbazole,
Polyvinyl pyrene, polyvinyl indoloquinoxaline,
Polyvinyl benzothiophene, polyvinyl anthracene, polyvinyl acridine, polyvinyl pyrazoline, polyacetylene, polythiophene, polypyrrole, polyphenylene, polyphenylene vinylene, polyisothianaphthene, polyaniline, polydiacetylene, polyheptadiene, polypyridine diyl, polyquinoline, polyphenylene sulfide, polyphenylene Conductive polymer compounds such as rosenylene, polyperinaphthylene, polyphthalocyanine,
As low molecular compounds, anthracene, pyrene, polycyclic aromatic compounds such as phenanthrene, indole, carbazole, imidazole, nitrogen-containing heterocyclic compounds such as, fluorenone, fluorene, oxadiazole, oxazole,
Pyrazoline, hydrazone, triphenylmethane, triphenylamine, enamine, stilbene compounds and the like can be used.

Examples of the electron-accepting substance include trinitrofluorenone, tetracyanoethylene, tetracyanoquinodimethane, quinone, diphenoquinone, naphthoquinone, anthraquinone and derivatives thereof, and Japanese Patent Application Laid-Open No. H07-163,873.
Specific quinone derivatives described in JP-A-1855853, specific diphenoquinone derivatives described in Japanese Patent Application Nos. 7-234732 and 7-319718, and the like can be used.

As the binder resin of the charge transfer layer, it is effective to contain a polycarbonate copolymer comprising a repeating unit represented by the general formulas (2) and (3).

In this case, the composition ratio of the repeating unit in the polycarbonate copolymer is not particularly limited as long as the polycarbonate copolymer can be synthesized. Although the molecular weight is not particularly limited, it may be 10,000 in terms of synthesis.
About 300,000 is preferred.

As a method for forming the charge transfer layer, various methods such as a known method can be used, and a coating solution in which a charge generating agent is dispersed or dissolved together with a binder resin in a suitable solvent is applied to a predetermined solution. A method of applying and drying on an underlayer can be used.

The electrophotographic photoreceptor of the present invention may contain a phenolic antioxidant in the photosensitive layer.

The phenolic antioxidants which can be used in the present invention include 2.6-di-tert-butylphenol, 2.6-di-tert-4-methoxyphenol, 2-tert-butyl-4-methoxyphenol Phenol, 2.4-dimethyl-6-tert-butylphenol, 2.6-di-tert-butyl-4-methylphenol, butylated hydroxyanisole, stearyl-propionate-β- (3.5-di-tert-butyl) -4-
Monophenols such as hydroxyphenyl), α-tocopherol, β-tocopherol, n-octadecyl-3- (3′-5′-di-tert-butyl-4′-hydroxyphenyl) propionate, and 2.2′-methylenebis (6-tert-butyl-4-methylphenol) 4.4'-butylidene-bis- (3-methyl-6
-Tert-butylphenol), 4.4'-thiobis (6-tert-butyl-3-methylphenol),
1.1.3-Tris (2-methyl-4-hydroxy-5
-Tert-butylphenyl) butane, 1.3.5-trimethyl-2.4.6-tris (3.5-di-tert)
-Butyl-4-hydroxybenzyl) benzene, tetrakis [methylene-3 (3.5-di-tert-butyl-
Polyphenols such as [4-hydroxyphenyl) propionate] methane are preferable, and one or more of these can be simultaneously contained in the photosensitive layer.

Of these phenolic antioxidants, monophenolic antioxidants are excellent in photosensitivity and compatibility with resins, and particularly, 2,6-di-ter- er represented by the formula (5).
It is effective to use t-butyl-4-methylphenol.

[0047]

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The electrophotographic photoreceptor of the present invention may contain an ultraviolet absorber in the photosensitive layer.

As the ultraviolet absorber which can be used in the present invention, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3.
5-bis (α, α-dimethylbenzyl) phenyl] -2
H-benzotriazole, 2- (3.5-di-tert)
-Butyl-2-hydroxyphenyl) benzotriazole, 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole,
2- (3.5-di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2-
(3.5-di-tert-amyl-2-hydroxyphenyl) benzotriazole, 2- (2'-hydroxy-
Benzotriazoles such as 5′-tert-octylphenyl) benzotriazole, and salicylic acids such as phenyl salicylate, p-tert-butylphenyl salicylate, and p-octylphenyl salicylate are preferred.
One or two or more of these can be simultaneously contained in the photosensitive layer.

The amount of the phenolic antioxidant added to the electrophotographic photoreceptor of the present invention is 3 to 3 with respect to the binder resin.
Preferably it is in the range of 20% by weight. On the other hand, the amount of the ultraviolet absorber added is preferably 3 to 30% by weight based on the binder resin.

It is more effective to add both a phenolic antioxidant and an ultraviolet absorber, but in that case, the addition amount of both components should be 5 to 40% by weight based on the binder resin. preferable.

When the addition amount of the phenolic antioxidant and the ultraviolet absorber is less than 5 to 40% by weight, the prevention of oxidation deterioration and the resistance to irritation tend to be weak. On the other hand, when the added amount of the phenolic antioxidant and the ultraviolet absorber exceeds 5 to 40% by weight, an increase in electrophotographic characteristics, particularly, a residual potential in a high-temperature and high-humidity environment may be observed.

In the case of the electrophotographic photosensitive member according to the present invention, the injection of free electrons from the conductive support to the photosensitive layer is prevented when the photosensitive layer is charged, and the photosensitive layer is integrated with the conductive support. Between the conductive support and the photosensitive layer for the purpose of preventing the reflection of incident light due to the unevenness of the conductive support, black spots and white spots of the image, etc. May be provided with an intermediate layer.

As the intermediate layer, aluminum oxide,
Polyethylene resin, acrylic resin, epoxy resin, polycarbonate resin, polyurethane resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, polyamide resin, nylon resin, and the like can be used. These intermediate layers may be composed of a single resin, or may be composed of a mixture of two or more resins. Further, an undercoat layer in which a metal oxide or carbon is dispersed in a resin can also be used.

Further, an organic thin film such as a polyvinyl formal resin, a polycarbonate resin, a fluororesin, a polyurethane resin or a silicone resin, or a thin film comprising a siloxane structure formed of a hydrolyzate of a silane coupling agent is formed on the photosensitive layer. And a surface protective layer may be provided. In this case, the durability of the photoconductor is improved, which is preferable.
This surface protective layer may be provided to improve functions other than the enhancement of durability.

[0056]

Hereinafter, examples of the electrophotographic photosensitive member according to the present invention will be described in detail along with comparative examples.

Example 1 A dispersion of oxytitanium phthalocyanine using polyvinyl butyral (trade name: BM-1 manufactured by Sekisui Chemical Co., Ltd.) as a binder was coated on a 30 mm-diameter aluminum cylindrical drum by dip coating. It is applied to a thickness of 0.1 μm to form a charge generation layer.

Then, a triphenylamine compound represented by the formula (6) is used as a charge transfer agent, and a polycarbonate copolymer comprising repeating units represented by the formulas (7) and (8) as a binder resin. (At this time, the composition (molar) ratio of the formulas (7) and (8) is 1: 9)
And the ratio of the charge transfer agent to the binder resin is set to 8:10 by weight, while the 2,6-di-tert-butyl-4-methyl represented by the formula (5) is used as an antioxidant. Phenol was used and dissolved in chloroform at a weight ratio of the charge transfer agent of 1: 9 to prepare a coating solution.

Then, this coating solution was applied onto the charge generation layer by dip coating, and then dried at 100 ° C. for 1 hour to form a 20 μm-thick charge transfer layer to produce a photoreceptor. .

[0060]

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[0061]

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[0062]

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Comparative Example 1 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transfer agent was changed to the butadiene compound represented by the formula (9).

[0064]

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Comparative Example 2 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the binder resin was changed to a polycarbonate comprising a repeating unit represented by the formula (10).

[0066]

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Comparative Example 3 An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that the binder resin was changed to a polycarbonate comprising a repeating unit represented by the above formula (8).

[Evaluation Method] The electrophotographic photoreceptors obtained in Example 1 and Comparative Examples 1 to 4 were measured for electrical characteristics and subjected to an image test using an actual machine to investigate the reduction in the thickness of the photosensitive layer.

The electrical characteristics were measured under the following conditions using a photoreceptor evaluation apparatus (manufactured by Yamanashi Electronics Co., Ltd.).

First, in an environment of normal temperature and normal humidity (24 ° C., 40% RH), each electrophotographic photosensitive member is charged by performing a corona discharge of −6 KV, and then adjusted to 200 Lux using a tungsten lamp as a neutralizing light. And irradiated. Then, the initial surface potential V ₀ (−V) was measured, and thereafter, 50 Lux white light was irradiated to measure the residual potential V _R (−V).

The dark decay DDR (%) was measured by measuring the surface potential V ₁₀ (−V) of each electrophotographic photosensitive member after being left in the dark for 10 seconds after the measurement of the initial surface potential V _{0. 10} /
V ₀ was determined.

The sensitivity was evaluated by setting the surface potential of each electrophotographic photosensitive member to -700 V and measuring the exposure E ₅₀ (erg / cm ² ) required to attenuate the surface potential to -350 V. .

As a rub resistance test, in Example 1 and Comparative Examples 1 to 3, each electrophotographic photosensitive member was negatively charged by a brush charging method, and was subjected to LED exposure, a non-magnetic one-component developing method, and a blade cleaning method. The printer was mounted on an electrophotographic apparatus for forming an image, and 5,000 sheets of A4 paper were printed. Each of the images printed in this manner was visually evaluated. In the judgment, ○ indicates that the printed image was good, and X indicates that the image had a defect. Table 2 summarizes the above evaluation results.

[0074]

[Table 2]

As understood from Table 2, the triphenylamine compound represented by the above formula (6) is used as the charge transfer agent, and the binder resin represented by the above formula (7) and (8) is used as the binder resin. The electrophotographic photoreceptor of Example 1 using a polycarbonate copolymer composed of repeating units having the following characteristics has high electrical characteristics, particularly high values of dark decay, and fog occurs in the initial image even when the process speed is low. There is no fear. Further, as understood from Table 2, the electrophotographic photoreceptor of Example 1 had good friction resistance.

On the other hand, in the electrophotographic photosensitive member of Comparative Example 1 using the charge transfer agent represented by the formula (9),
The value of dark decay is considerably lower than that of the electrophotographic photoreceptor of Example 1, and fog is likely to occur in an initial image. In particular, in a device having a low process speed, that is, in a device having a long time from charging to development, this phenomenon becomes remarkable.

Further, the electrophotographic photosensitive members of Comparative Examples 2 and 3 have a large film loss and are apt to be scratched on the surface of the photosensitive members, so that density unevenness or streaks may occur in a printed image. Was. These problems are fatal drawbacks, especially in a device having a high process speed.

As described above, according to the electrophotographic photoreceptor of Example 1, it was clarified that stable and good images could be obtained in various electrophotographic apparatuses regardless of whether the process speed was high or low.

[0079]

As described above, according to the present invention, it is possible to obtain an electrophotographic photosensitive member having high mechanical strength and excellent electrophotographic properties, in particular, excellent charge retention on the photosensitive layer surface, that is, excellent dark decay. be able to. Therefore, according to the electrophotographic photoreceptor of the present invention, stable and good images can be obtained in various electrophotographic apparatuses regardless of whether the process speed is high or low, so that versatility is improved and cost reduction is possible. The effect is obtained.

Claims (2)

[Claims] 1. An electrophotographic photosensitive member having a photosensitive layer containing at least a charge generator, a charge transfer agent and a binder resin on a conductive support, wherein the charge transfer agent is represented by the general formula (1): An electrophotographic photoreceptor comprising using a triphenylamine compound represented by the formula (I) and a polycarbonate copolymer comprising repeating units represented by the formulas (2) and (3) as the binder resin. body. Embedded image [In the formula, R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ may be the same or different, and each has a hydrogen atom, a halogen atom, a lower alkyl group, an alkoxy group, and a substituent. May represent an aryl group, or R ₁ , R ₂ and R ₃ , R ₄ may be bonded to each other to form a ring, and a is 0 or 1
Is shown. [Chemical formula 2] Wherein, X is -CR ₆ R ₇ - (where, R ₆ and R ₇ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, trifluoromethyl group or an aryl group having 6 to 12 carbon atoms Represents a 1,1-cycloalkylene group having 5 to 8 carbon atoms, an α, ω-alkylene group having 2 to 12 carbon atoms, a single bond,-
O -, - CO -, - S -, - SO- or -SO ₂ - shows a. [Chemical formula 3] [Wherein, R ₈ and R ₉ each independently represent a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms, b and c each independently represent an integer of 0 to 4, and Y is It has the same meaning as X in the formula (2). However, X and Y may be the same or different. ] 2. The electrophotographic photoreceptor according to claim 1, wherein oxytitanium phthalocyanine is used as a charge generating agent.