JPH03212649A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To prevent the deterioration of a sensitive body due to ozone and various ions and to render high quality to images over a long period of time by incorporating a prescribed resin and a prescribed amt. of a phenolic antioxi dant into the surface protecting layer. CONSTITUTION:When a photoconductive layer such as an Se alloy layer and a surface protecting layer are laminated on an electrically conductive substrate to obtain a sensitive body, one or more kinds of resins selected among an acrylonitrile-butadiene-styrene copolymer a styrene-acrylonitrile copolymer, a chlorinated polyethylene-acrylonitrile-styrene copolymer and chlorinated poly ethylene and a phenolic antioxidant such as 2,6-di-t-butyl-p-cresol are incorpo rated into the protecting layer. The antioxidant is used in 1/9-3/1 weight ratio to the resins.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, particularly to an improvement in an electrophotographic photoreceptor having a surface protective layer on the surface of a photoconductive layer.

[Prior art]

Conventionally, electrophotographic photoreceptors have been prepared by providing a photoconductive layer mainly made of selenium or a selenium alloy on a conductive support, or by dispersing an inorganic photoconductive material such as zinc oxide or cadmium sulfide in a binder. Those using organic photoconductive materials such as poly-N-vinylcarbazole and trinitrofluorenone or azo pigments, and those using amorphous silicon are generally known.

However, when the photoconductive layer of these photoconductors is exposed, the life of the photoconductor is shortened due to damage caused by corona discharge during the charging process and physical or chemical damage caused by contact with other parts during the copying process. However, it was not possible to maintain high image quality for a long time.

As a method for eliminating such drawbacks, a technique is known in which a protective layer is provided on the surface of the photoreceptor. Specifically, a method of providing an organic film on the surface of a photosensitive layer (Japanese Patent Publication No. 38-1544
6), Method of providing inorganic oxide (Japanese Patent Publication No. 43-1451
7) A method of laminating an insulating layer after providing an adhesive layer (Japanese Patent Publication No. 43-27591), or plasma CVD method, optical C
A-3i layer, a-5i:N:H layer, a
-5i: Method of laminating O-H layers, etc. (Unexamined Japanese Patent Publication No. 57-17
No. 9859, Japanese Unexamined Patent Publication No. 59-58443/).

However, since the protective layer of these photoreceptors has a high electrophotographic resistance (10"Ω·011 or more), there are drawbacks such as an increase in residual potential and accumulation of charged potential during repeated use.

As a technique for compensating for the above drawbacks, a method of optimizing the resistance by changing the composition of the protective layer resin (Japanese Patent Publication No. 52-024414) is known. Also, a method in which the protective layer is a photoconductive layer (Japanese Patent Publication No. 48-038427, Japanese Patent Publication No. 43-016198, Japanese Patent Publication No. 49-010258, USP-2901348)
, a method of adding a transfer agent such as a dye or a Lewis acid into the protective layer (Japanese Patent Publication No. 44-000834, Japanese Patent Application Laid-Open No. 53-1
33444), or a method of controlling the resistance of the protective layer by adding metal or metal oxide fine particles (Japanese Patent Laid-Open No. 53-003)
338) etc. have been proposed.

However, in the latter case, the protective layer absorbs light, reducing the amount of light reaching the photosensitive layer, which may result in a problem of lowering the sensitivity of the photoreceptor. From this point of view, as proposed in JP-A-57-030546, metal oxide fine particles with an average particle size of 0.3 μs or less are dispersed in the protective layer as a resistance control agent to make the protective layer substantially transparent to visible light. There are known ways to do this.

A photoreceptor with a protective layer as described above has the advantage that there is little decrease in sensitivity and the mechanical strength of the protective layer is increased and durability is improved. Later, if the copy image is placed in an environment of high humidity or a sudden increase in humidity, there is a problem that a so-called image blur occurs, in which the copied image is blurred. The cause of this is not yet clear, but when the photoreceptor is repeatedly exposed to corona discharge, the protective layer resin is oxidized and degraded by ozone and various ions generated by the corona discharge, causing the structure to be severed and radicals to be formed. In addition, ozone and various ions released from the corona react with impurities such as moisture and carbon dioxide gas in the air to form hydrophilic compounds containing nitrogen compounds, carboxyl groups, aldehyde groups, etc. These substances are strongly chemically adsorbed to the deteriorated parts of the surface of the protective layer, so if the humidity is high or the humidity rises rapidly, a large amount of moisture will be adsorbed to the surface of the photoreceptor, increasing the two-dimensional resistance of the surface. This seems to be due to the fact that the image quality is lowered and image deletion occurs.

From this point of view, CTL/CG is a device that prevents the surface of a dispersed photosensitive layer from deteriorating in an oxidizing atmosphere such as ozone generated during corona charging (Japanese Patent Application Laid-open No. 59-163/44).
CGL of a positively charged photoreceptor laminated in the order of L/protective layer or a protective layer containing a specific antioxidant to prevent deterioration of charging ability due to ozone (Japanese Patent Laid-Open No. 63-4466
2, JP-A-63-50848-50851, JP-A-63
-52146 and JP-A-63-52150) have also been proposed.

However, these photoreceptors have not been sufficiently effective in preventing image fading over a long period of time under high humidity conditions after repeated use.

[Problem to be solved by the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor that is completely free from deterioration due to ozone and various ions generated by corona discharge and provides good image quality over a long period of use.

[Means to solve the problem]

According to the present invention, in an electrophotographic photoreceptor in which a photoconductive layer and a surface protective layer are sequentially laminated on a conductive support, the surface protective layer is made of acrylonitrile/butadiene/styrene copolymer resin, styrene/acrylonitrile copolymer resin, etc. polymer resin,
Contains at least one resin selected from chlorinated polyethylene/acrylonitrile/styrene copolymer resin and chlorinated polyethylene resin and a phenolic antioxidant, and the amount of the phenolic antioxidant added is in a weight ratio to the resin. Provided is an electrophotographic photoreceptor characterized in that the ratio is 1/9 to 3/1.

As a result of various studies, the present inventors found that phenolic antioxidants are effective in preventing deterioration caused by ozone and various ions generated by corona discharge, and are also highly compatible with the above-mentioned specific resins. The present inventors have discovered that good image quality can be maintained over a long period of time without any side effects when the protective layer is formed by blending them in a specific proportion.

Examples of the phenolic antioxidant used in the present invention include the following compounds, which may be used alone or in combination of two or more.

Phenolization inhibitor 2.6-di-t-butyl-p-cresol (BHT),
2,6-di-t-butylphenol, 2,4-di-methyl-6-t-butylphenol, butylhydroxyanisole, 2,2'-methylenebis(4-methyl-6-t-butylphenol)
-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), bisphenol A,
OL-α-tocopherol, styrenated phenol,
Styrenated cresol, 3,5-di-t-butylhydroxybenzaldehyde, 2,6-di-t-butyl-4-
Hydroxymethylphenol, 2゜6-di-S-butylphenol, 2,4-di-t-butylphenol, 3,
5-di-t-butylphenol, o-n-butoxyphenol, o-t-butylphenol tylphenol, p
-t-butylphenol, 0-isobutoxyphenol, on-propoxyphenol, 0-cresol, 4
．． 6-di-t-butyl-3-methylphenol, 2,6
-Simethylphenol, 2,3,5,6-titramethylphenol, 3-(3',5'-di-t-butyl-4'
-hydroxyphenyl)propionic acid stearyl ester, 2,4,6,-tri-t-butylphenol,
2,4,6-trimethylphenol, 2,4,6-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)mesitylene, 1.

6-hexanethiolubis(3(3.5-di-t-butyl-4-hydroxyphenyl)propionate), 2
,2-thio-diethylenebis[:3-(3,5-di-t
-butyl-4-hydroxyphenyl)propionate]
, 2,2-thiobis(4-methyl-6-t-butylphenol), 3,5-di-t-butyl-4-hydroxybenzylphosphate-diethyl ester, 1,3.
5-trimethyl-2,4,6-tris (3.

5-di-t-butyl-4-hydroxybenzyl)benzene, n-octadecyl-3-(3',5'-di-t-butyl-4-hydroxyphenyl)propionate, 2-
t-butyl-6 (3'-t-butyl-5'-methyl-2
-hydroxybenzyl)-4-methylphenylacrylate, 4,4'-butylidene-bis(3-methyl-6-
t-butylphenol), hydroquinone, 2,5-di-t-butylhydroquinone, tetramethylhydroquinone, etc.

In the present invention, the resin contained in the protective layer is acrylonitrile/
It is at least one resin selected from butadiene/styrene copolymer resin, styrene/acrylonitrile copolymer resin, chlorinated polyethylene/acrylonitrile/styrene copolymer resin, and chlorinated polyethylene resin.

Acrylonitrile/butadiene/styrene copolymer resins are represented by the following general formula and are easily available commercially under the trade names shown in the table below. Two or more of these may be used in combination.

Typical examples of acrylonitrile butadiene styrene copolymer resins Styrene/acrylonitrile copolymer resins are commercially available and easily available under the following general formula % and the trade names shown in the table below.

These can be used by mixing two or more types. I don't mind if you stay.

A representative example of a styrene acrylonitrile copolymer resin (AC5 resin) is represented by the following general formula (%) () (), and two or more of these may be used as a mixture.

The chlorinated polyethylene resin is represented by the following general formula and is easily available commercially under the trade names shown in the table below. Two or more of these may be used in combination.

Typical example of chlorinated polyethylene resin The amount of phenolic antioxidant added to the resin is 179 to 3/1 in weight ratio, more preferably 1/1 to 3/1.
It is 5/2. If the amount added is less than 179, the effect of suppressing deterioration caused by ozone and various ions will not last long, and if the amount added is more than 3/1, the phenolic antioxidant will precipitate on the surface of the surface protective layer, resulting in a cloudy appearance. Furthermore, the mechanical strength of the surface protective layer decreases, and the surface protective layer film is easily scratched when used in a copying machine, resulting in a decrease in durability.

The specific resistance of the surface protective layer is 1010 to 1013 Ωcm, preferably 10"-10"Ω"cm, and 1010Ω'
cm or less, the sharpness of the image decreases, and 1013Ω・
cm or more, background staining of the image occurs, and this tendency becomes more pronounced as the thickness of the surface protective layer increases.

The above-mentioned specific resin usually has a volume resistivity of about 101@Ω・Cl11, and in order to be used as a surface protective layer, it must be used with a film thickness of about 5000 μL, or some kind of resistance control agent must be added. and its volume resistance is 10
It is desirable to lower the resistance to about 12Ω·cm. In the latter case, the film thickness can be set arbitrarily, and when the film thickness is increased to about 5 mm, the mechanical strength increases and the durability is further improved.

Resistance control agents include fatty acid salts, higher alcohols, sulfuric esters, fatty acid amines, quaternary ammonium salts, alkylpyridium salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, sorbitan alkyl esters, and imidacillin. Derivative anionic, cationic, or nonionic organic electrolytes; Metals such as Au, Ag, Cu, Ni, and AQ; Zn
Metal oxides such as O1Tie2, SnO□, In2O3, 5b2o, containing SnO, In2O, containing SnO□; M
gF, ,CaF, ,BiF, ,AQF, ,SnF, ,S
Metal fluorides such as nF, TiF, etc.; tetraisopropyl titanate.

Examples include organic titanium compounds such as tetra-n-butyl titanate, titanium acetylacetonate, and titanium lactate ethyl ester; and mixtures thereof.

To form the surface protective layer of the present invention, first, the above-mentioned specific resin is dissolved in an appropriate solvent, and the volume resistivity of the surface protective layer is 1.
One or more of the above resistance control agents are added so that the resistance becomes about 0.012 Ω·cm. If the resistance control agent is not compatible with the specific resin, a means such as a ball mill may be used as necessary. Next, a phenolic antioxidant is added in a weight ratio of 179 to 3/1 to the specific resin in the surface protective layer forming liquid, and the mixture is coated on the photoconductive layer, dried, and cured.

In the electrophotographic photoreceptor of the present invention, conventional structures and forming methods for the photoconductive layer and the conductive support other than the surface protective layer can be applied as they are.

That is, as a constituent material of the photoconductive layer, Se or 5
Se-based alloys such as e-Te, As, Se, etc.: ZnO1
A system in which particles of II-Vl group compounds such as CdS and CdSe are dispersed in a resin; an organic photoconductive material such as polyvinylcarbazole and anthracene; amorphous Si, etc. are used.

As a method for forming the photoconductive layer, methods such as vapor deposition, sputtering, and coating are appropriately selected. The structure of the photoconductive layer is not particularly limited and may be a single layer or a laminate of a charge generation layer containing the photoconductive material as a main component and a charge transport layer containing a donor or acceptor as a main component. The film thickness is 3 to 1100 IJ in the case of a single-layer photoconductive layer, 0.05 to 3 pm for the charge generation layer in the case of a laminated photoconductive layer,
For the charge transport layer, a range of 3 to 100 is appropriate.

In the present invention, an adhesive layer for increasing adhesion between the surface protective layer and the photoconductive layer, and an electrical barrier layer for preventing charge injection. A solvent-resistant layer may be provided to prevent erosion of the conductive layer.

The conductive support according to the present invention includes A1, Ni, F
Metals or alloys such as e, Cu, Au; polyester,
Examples include those in which a metal film such as A1, Ag, Au, or a metal oxide film such as In2O, SnO□, etc. is provided on an insulating substrate such as plastic or glass such as polycarbonate or polyimide; electrically conductive treated paper, etc. Although the shape is not particularly limited, it is usually plate-shaped, drum-shaped, or belt-shaped.

〔Example〕

The present invention will be explained below by way of examples.

Example 1 An AQ drum support of 80 mmφ x 340 m+i (length) was set in a vacuum evaporation apparatus, and As, Se, and alloy were placed in the evaporation source boat of this apparatus, and the vacuum degree was 3 x 1.
Vapor deposition was performed under the conditions of 0''-' Torr, support temperature of 200° C., and boat temperature of 450° C. to form a photoconductive layer with a thickness of 60 Ijs on the support.

Next, on top of this, a) an alkoxy group-containing polysiloxane, b) a hydroxyl group-containing polysiloxane, and C) at least one amino group, imino group, or nitrile group bonded to a carbonate atom.
Silicone resin A (
AY42-440) manufactured by Toray Silicone Co., Ltd. and the above a),
Equivalent amount (weight) of silicone resin B (AY42-441 manufactured by Toray Silicone Co., Ltd.) with different component ratios of b) and C)
A glue groin solution of the mixture was applied and dried at 120°C for 1 hour to give a 0.1. A thick electrical barrier layer was formed. Next, 5wt of acrylonitrile/butadiene/styrene copolymer resin (Tufflex: manufactured by Mitsubishi Monsando Co., Ltd.)
After dispersing 60 parts by weight of the % solution and 2 parts by weight of the resistance control agent SnO and fine powder in a ball mill for 120 hours, 0.45 parts by weight of 2,6-di-t-butyl-p-cresol (BHT) was added, Coat this on the electrical barrier layer and
Drying was carried out for 1 hour at .degree. C. to form a surface protective layer having a thickness of 5 tones, thereby producing an electrophotographic photoreceptor.

Example 2 An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the amount of 2.6-di-t-butyl-P-cresol (BIT) was changed to 3 parts by weight.

Example 3 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the amount of 2.6-di-t-butyl-P-cresol (BIT) added was changed to 7.5 parts by weight.

Example 4 Phenolic antioxidant 2,6-di-t-butyl-p
An electrophotographic photoreceptor was produced in the same manner as in Example 2 except that -cresol (BIT) was replaced with 2,6-di-t-butylphenol.

Example 5 Phenolic antioxidant 2,6-di-t-butyl-P
An electrophotographic photoreceptor was produced in exactly the same manner as in Example 2, except that -cresol (BHT) was replaced with 2,5-di-t-butylhydroquinone.

Example 6 A photoconductive layer was formed on the AM drum support in exactly the same manner as in Example 1, and then 2 parts by weight of zirconium butyrate,
A solution consisting of 1 part by weight of γ-glycidoxypropyltrimethoxysilane, 40 parts by weight of BuOH, and 30 parts by weight of MeOH was placed on the photoconductive layer, and dried at 120°C for 2 hours.
．． The zero-order resistance control agent that formed the electrical barrier layer with a thickness of 2 tones was replaced with AQF□ powder from SnO2 fine powder, and the phenolic antioxidant was replaced with 2,6-di-t-butyl-p-cresol (BHT). A surface protective layer was formed in the same manner as in Example 2, except that 3,5-di-t-butyl-4-hydroxy-benzylphosphate-diethyl ester was used, and an electrophotographic photoreceptor was prepared.

Example 7 On a drum support of 80nv+φ
: A solution prepared by adding 1/100,000 of the total weight of silicone oil (KF50, manufactured by Shin-Etsu Chemical Co., Ltd.) to a solution of 1:8 was applied and dried to form a charge transport layer with a film thickness of 20 pa.

Next, on top of this, a disazo pigment with the following structure (■) and a solid content of polyester resin (Byron 200, manufactured by Toyobo ■) were added in a weight ratio of 5=2, and tetrahydrofuran and ethyl cellosolve were added as a dispersion medium in a weight ratio of 4:6. A dispersion liquid was applied so that the solid content concentration was 1% by weight, and dried to a concentration of 0.5% by weight.
．． A thick charge generation layer was provided to form a photoconductive layer.

Next, polyamide 5 wt % methanol/butanol was coated on this photoconductive layer and dried at 120° C. for 20 minutes to form an electrical barrier layer with a thickness of 0.1 mm.

A phenolic antioxidant, 2,6-di-t-butyl-p-cresol (BIT), is then applied onto this electrical barrier layer.
A surface protective layer was formed in the same manner as in Example 1, except that DL-α-tocopherol was used instead of DL-α-tocopherol, and an electrophotographic photoreceptor was produced.

Example 8 Electron production was carried out in the same manner as in Example 1, except that in Example 8, the acrylonitrile/butadiene/styrene copolymer resin was replaced with a styrene/acrylonitrile copolymer resin (Sunrex, manufactured by Mitsubishi Monsando Kasei Co., Ltd.). A photographic photoreceptor was produced.

Example 9 An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the amount of 2.6-di-t-butyl-p-cresol (BIT) was changed to 3 parts by weight.

Example 10 An electrophotographic photoreceptor was produced in the same manner as in Example 8, except that the amount of 2.6-di-t-butyl-p-cresol (BIT) was changed to 7.5 parts by weight.

Example 11 Phenolic antioxidant 2,6-di-t-butyl-p
-Cresol (B)! An electrophotographic photoreceptor was produced in the same manner as in Example 9 except that 2,6-di-t-butylphenol was used instead of T).

Example 12 Phenolic antioxidant 2,6-di-t-butyl-p
An electrophotographic photoreceptor was prepared in the same manner as in Example 9 except that 2,5-di-t-butylhydroquinone was used instead of -cresol (B)IT).

Example 13 An electrophotographic photoreceptor was produced in the same manner as in Example 6, except that the acrylonitrile/butadiene/styrene copolymer resin was replaced with a styrene/acrylonitrile copolymer resin.

Example 14 An electrophotographic photoreceptor was produced in the same manner as in Example 7 except that the acrylonitrile/butadiene/styrene copolymer resin was replaced with a styrene/acrylonitrile copolymer resin.

Example 15 In Example 1, the acrylonitrile/butadiene/styrene copolymer resin was replaced with chlorinated polyethylene/styrene/
An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that an acrylonitrile copolymer resin (AC3 resin, manufactured by Showa Denko KK) was used instead.

Example 16 An electrophotographic photoreceptor was prepared in the same manner as in Example 15, except that the amount of 2.6-di-t-butyl-p-cresol (BIT) was changed to 3 parts by weight.

Example 17 An electrophotographic photoreceptor was produced in the same manner as in Example 15, except that the amount of 2.6-di-t-butyl-p-cresol (BIT) was changed to 7.5 parts by weight.

Example 18 Phenolic antioxidant 2,6-di-t-butyl-P
An electrophotographic photoreceptor was prepared in the same manner as in Example 16 except that -cresol (BIT) was changed to 2,6-di-t-butylphenol.

Example 19 Phenolic antioxidant 2,6-di-t-butyl-p
An electrophotographic photoreceptor was prepared in the same manner as in Example 16 except that 2,5-di-t-butylhydroquinone was used instead of -cresol (BHT).

Example 20 An electrophotographic photoreceptor was produced in the same manner as in Example 6, except that the acrylonitrile/butadiene/styrene copolymer resin was replaced with a chlorinated polyethylene styrene/acrylonitrile copolymer resin.

Example 21 An electrophotographic photoreceptor was produced in the same manner as in Example 7, except that the acrylonitrile/butadiene/styrene copolymer resin was replaced with a chlorinated polyethylene styrene/acrylonitrile copolymer resin.

Example 22 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the acrylonitrile/butadiene/styrene copolymer resin in Example 1 was replaced with a chlorinated polyethylene resin (Elastrene: manufactured by Showa Denko KK). Created.

Example 23 An electrophotographic photoreceptor was produced in the same manner as in Example 22, except that the amount of 2.6-di-t-butyl-P-cresol (BIT) added was changed to 3 parts by weight.

Example 24 An electrophotographic photoreceptor was produced in the same manner as in Example 22, except that the amount of 2.6-di-t-butyl-p-cresol (BIT) was changed to 7.5 parts by weight.

Example 25 Phenolic antioxidant 2,6-di-t-butyl-p
An electrophotographic photoreceptor was prepared in the same manner as in Example 23 except that -cresol (BIT) was changed to 2,6-di-t-butylphenol.

Example 26 Phenolic antioxidant 2,6-di-t-butyl-p
An electrophotographic photoreceptor was produced in exactly the same manner as in Example 23, except that 2,5-di-t-butylhydroquinone was used instead of -cresol (BIT).

Example 27 An electrophotographic photoreceptor was produced in the same manner as in Example 6 except that the acrylonitrile/butadiene/styrene copolymer resin was replaced with a chlorinated polyethylene resin.

Example 28 An electrophotographic photoreceptor was produced in the same manner as in Example 7 except that the acrylonitrile/butadiene/styrene copolymer resin was replaced with a chlorinated polyethylene resin.

Comparative Example 1 Example 1 except that 2,6-di-t-butyl-p-cresol (BHT), which is a phenolic antioxidant, was not added.
An electrophotographic photoreceptor was produced in exactly the same manner as described above.

Comparative Example 2 An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that the amount of 2.6-di-t-butyl-P-cresol (BHT) added was changed to 0.03 parts by weight.

Comparative Example 3 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the amount of 2.6-di-t-butyl-P-cresol (BIT) was changed to 12 parts by weight.

Comparative Example 4 An electrophotographic photoreceptor was produced in the same manner as in Example 7 except that DL-α-tocopherol, which is a phenolic antioxidant, was not added.

The electrophotographic photoreceptors produced in Examples 1 to 28 and Comparative Examples 1 to 4 were installed in a plain paper copying machine (FT6550 manufactured by Ricoh), and the results of evaluating changes in resolution due to the image forming environment for each number of copies are shown in Table 1. Shown in 1.

As is clear from Table 1, products that use the above-mentioned specific resin as the binder resin of the surface protective layer and further add a specific amount of phenolic antioxidant can be used for a long period of time regardless of environmental changes. It can be seen that this is a highly reliable electrophotographic photoreceptor that can maintain good image quality.

The amount of phenolic antioxidant added to the specific resin is preferably 179 to 3/1 in terms of weight ratio, and if the amount added is less than 1/9, the effect of suppressing image fading under high temperature and high humidity due to ozone and various ions will continue. It can be seen that if the addition ratio is 3/1 or more, the surface of the surface protective layer film becomes cloudy and rough from the beginning, and the mechanical strength of the film deteriorates.

〔effect〕

The electrophotographic photoreceptor of the present invention does not deteriorate at all due to ozone and various ions generated by corona discharge, and can maintain good image quality over long periods of use regardless of environmental changes. .

Claims (1)

[Claims] (1) In an electrophotographic photoreceptor in which a photoconductive layer and a surface protective layer are sequentially laminated on a conductive support, the surface protective layer is made of an acrylonitrile/butadiene/styrene copolymer resin,
Contains at least one resin selected from styrene/acrylonitrile copolymer resin, chlorinated polyethylene/acrylonitrile/styrene copolymer resin, and chlorinated polyethylene resin and a phenolic antioxidant, and the amount of the phenolic antioxidant added. is 1/1 in weight ratio to the resin.
An electrophotographic photoreceptor having a ratio of 9 to 3/1.