JPH0391762A - Electrophotoraphic sensitive body - Google Patents

Abstract

PURPOSE:To provide an electrophotographic sensitive body high in sensitivity and durability by incorporating a specified bismesoionic compound in a photosensitive layer. CONSTITUTION:The photosensitive layer contains the bismesoionic compound represented by general formula I in which A is phenylene or naphthylene, and R is an optionally substituted hydrocarbon group or heterocyclic group. The photosensitive body can be prepared by dispersing the bismesoionic compound into a binder solution, coating a conductive substrate with this dispersion fluid, and drying it.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor having a photosensitive layer containing a bismesoion compound.

[Conventional technology]

So-called electrophotography, which combines photoconductive substances and electrostatic phenomena to record images, was developed by Carlson in U.S. Pat.
It originated from the ``electron photography'' that was revealed in issue 1776. In electrophotography, a photoconductive material whose electrical resistance changes depending on the amount of light irradiation is used.
A photoconductive material that is dispersed in an insulating binder resin and coated on a support is used as a photoreceptor. After this photoconductive material is given a uniform surface charge by corona charging in a dark place, it loses its surface charge depending on the brightness value of image exposure, and an electrostatic latent image is formed. This kind of electrostatic latent image is
The surface is then treated with a suitable electrolytic indicator material, ie, toner, to form a visible image. The toner can be used with a dry carrier or colloidally suspended in an organic solvent and can be deposited by Coulomb force depending on the charge of the electrostatic latent image. The attached display substance can be fixed by heat, pressure, or the like.

The electrostatic latent image can also be transferred to a second support (eg, paper, film, etc.), developed, and fixed.

In such electrophotography, the basic characteristics required of an electrophotographic photoreceptor are (I) ability to be charged to an appropriate potential in the dark, and (2) ability to retain charge in the dark. and (3) the ability to quickly dissipate charge by light irradiation.

In addition, from a practical standpoint, (4) a photoreceptor with an appropriate area can be easily manufactured, (5) it has good repeat stability,
(6) It must be durable, and (7) It must be inexpensive.

Conventionally, selenium, cadmium sulfide, zinc oxide, and the like have been widely used as photoconductive materials for electrophotographic photoreceptors. However, while these inorganic compounds have many advantages, they also have various disadvantages. For example, selenium has drawbacks such as difficult manufacturing conditions, high manufacturing costs, and the need for careful handling as it easily crystallizes due to temperature, humidity, fingerprints, etc., and deteriorates its properties as a photoreceptor. had. Further, cadmium sulfide has particularly poor moisture resistance, and auxiliary means such as installing a heater are required to prevent the photoreceptor from absorbing moisture. In addition, zinc oxide has problems with mechanical strength such as hardness and abrasion resistance, and since it is sensitized with dyes such as rose bengal, photobleaching of the dye due to corona charging can shorten the life of the photoreceptor. It was shrinking. These inorganic compounds contain heavy metals, and if handled incorrectly, there is a risk of developing a pollution problem.

In recent years, in order to overcome the drawbacks of these inorganic compound photoconductive materials, research and development of electrophotographic photoreceptors using various organic photoconductive compounds has been actively conducted. for example,
An electrophotographic photoreceptor made of poly-N-vinylcarhazole and 2,4,7-trinitrofluorenone (U.S. Pat. No. 3,484,237), poly-N-vinylcarhazole enhanced with a pyrylium salt dye. (Japanese Patent Publication No. 48-25658), and one using a eutectic consisting of dye and resin as a photoconductive material (Japanese Patent Publication No. 47-10785)
and so on. Compared to inorganic compound-based electrophotographic photoreceptors, such organic compound-based electrophotographic photoreceptors have the advantage of being easier to form a film, have extremely high productivity, and can provide inexpensive photoreceptors. There is. However, for photoconductive polymers such as poly-N-vinylcarbazole, the polymer alone has poor filmability, flexibility, adhesion, etc., and in order to improve these defects, plasticizers, binders, etc. is added, but this may cause a decrease in sensitivity or
There were problems such as an increase in residual potential.

In addition, organic compound-based low-molecular photoconductive compounds have a wide range of binders to choose from, and if an appropriate polymer is selected,
Although it is possible to produce products with excellent mechanical properties such as filmability and adhesiveness, on the other hand, they do not fully satisfy the requirements for electrophotographic photoreceptors such as photosensitivity and repeatability.

[Problems to be solved by the present invention]

The problem to be solved by the present invention is to overcome the drawbacks of conventional inorganic compound-based electrophotographic photoreceptors, and improve the drawbacks of the organic compound-based electrophotographic photoreceptors that have been proposed so far, so as to be fully practical. The object of the present invention is to provide an electrophotographic photoreceptor having high sensitivity and high durability that can be used for various purposes.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a photosensitive layer containing the general formula (
I) (wherein A represents a phenylene group or a naphthylene group,
R represents a hydrocarbon group which may have a substituent or a heterocyclic group which may have a substituent. ) Provided is an electrophotographic photoreceptor characterized by containing a bismesoionic compound represented by:

R in general formula (I) is preferably an alkyl group having 1 to 20 carbon atoms, an aromatic hydrocarbon group such as a phenyl group or a naphthyl group, a biridyl group, a carbazolyl group, a penzotriazolyl group, etc. Examples include aromatic heterocyclic groups. As a specific example, when R is an alkyl group,
Methyl group, ethyl group, probyl group, butyl group, bentyl group, hexyl group, isobrobyl group, isobutyl group, isoamyl group, isohexyl group, neopentyl group, ter
Examples include t-butyl group. When R is a substituted alkyl group, examples of the substituent include a halogen atom, a nitro group, a cyano group, a hydroxy group, a substituted hydroxy group, a thiol group, a substituted thiol group, an amino group, a substituted ξ group,
Examples include aryl groups.

Specific examples of R include halogenoalkyl groups (e.g., chloromethyl group, trifluoromethyl group, 2-promoethyl group, etc.), nitroalkyl groups (e.g., nitromethyl group, 3-nitroprobyl group, etc.), cyanoalkyl groups ( For example, cyanomethyl group, 2-cyanoethyl group, etc.), hydroxyalkyl group (e.g., hydroxymethyl group, 2-hydroxyethyl group, 3-hydroxybutypyl group, 2-hydroxyprobyl group, etc.), substituted hydroxyalkyl group ( For example, methoxymethyl group, 2-methoxyethyl group, ethoxymethyl group, phenoxymethyl group, etc.), thiohydroxyalkyl group (for example, thiohydroxymethyl group, 2-
thiohydroxyethyl group, etc.), substituted thiohydroxyalkyl group (e.g., methylthiomethyl group, 2-methylthioethyl group), aminoalkyl group (e.g., aminomethyl group, 2-aminoethyl group, etc.), substituted aminoalkyl group (
For example, methylaminomethyl group, ethylaminomethyl group, dimethyla4nomethyl group, 2-(dimethylamino)ethyl group, phenylagonomethyl group, diphenylaminomethyl group, etc.) can be mentioned.

When R is an aromatic hydrocarbon group or an aromatic heterocyclic group, examples of the substituent include an alkyl group, a halogen atom, a ditro group, a cyano group, a hydroxy group, a substituted hydroxy group, a thiol group, a substituted thiol group, and an alkyl group. There are ξ-no groups, substituted ξ-no groups, etc. Specific examples of R being a substituted phenyl group include alkylphenyl group (e.g. tolyl group, ethylphenyl group, etc.), chlorophenyl group, nitrophenyl group, cyanophenyl group, hydroxyphenyl group, Kt'A
Hydroxyphenyl group (e.g. methoxyphenyl group,
ethoxyphenyl group, etc.), thiohydroxyphenyl group,
Substituted thiol groups (e.g., methylthiophenyl group, ethylthiophenyl group, etc.), aminophenyl groups, substituted amino groups (e.g., methylanξnophenyl group, dimethylaminophenyl group, phenylaminophenyl group, diphenylaminophenyl group) etc.). Examples of fused aromatic hydrocarbon groups in which R is a substituted naphthyl group include alkylnaphthyl groups (e.g., methylnaphthyl group, ethylnaphthyl group, etc.), chloronaphthyl group, nitronaphthyl group, cyanonaphthyl group, hydroxy Naphthyl group, substituted hydroxynaphthyl group (e.g., methoxynaphthyl group, ethoxynaphthyl group, etc.), thiohydride xynaphthyl group, substituted thiol group (e.g., methylthionaphthyl group, ethylthionaphthyl group, etc.), aminonaphthyl group, substituted amino group ( For example, there are methylaminonaphthyl group, dimethylaminonaphthyl group, phenylaminonaphthyl group, diphenylaminonaphthyl group, etc.). Examples of aromatic heterocyclic groups include substituted henzothiazolyl groups, such as alkylbenzothiazolyl groups (e.g., methylbenzothiazolyl group, ethylbenzobenzothiazolyl group, etc.), chloropenzothiazolyl group, etc. group, nitrobenzothiazolyl group, cyanobenzothiazolyl group, hydroxybenzothiazolyl group, substituted hydroxybenzothiazolyl group (e.g., methoxybenzothiazolyl group, ethoxybenzothiazolyl group, etc.), thio Hydroxybenzothiazuryl group, substituted thiol group (e.g.
(methylthiobenzothiazolyl group, ethylthiohenzothiazolyl group, etc.), aminobenzothiazolyl group, substituted aminobenzothiazolyl group (e.g., methylanobenzothiazolyl group, dimethylanobenzothiazolyl group) group, phenylaminobenzthiazuryl group, diphenyl-5nonabenzothiazuryl group, etc.). In these examples, if the position of the substituent is not specified, any of the possible isomers may be used. Further, it may be a substituted aromatic hydrocarbon group or a substituted aromatic heterocyclic group having two or more of these substituents (which may be the same or different).

The bismesoionic compound represented by the general formula (I) according to the present invention can be produced by a conventionally known method.

For example, "Hemisos Berinhte", vol. 120, 61
(1987), it can be synthesized by the following route.

S S S COOH (r) The above general formula (I) used in the present invention The bisme of Specific examples of soyionic compounds are shown in Table 1 with structure 2.

Part ■ Table No? - N? The electrophotographic photoreceptor of the present invention can have various structures. Examples are shown in Figures 1-4. The photoreceptor in FIG.
A photosensitive layer (2a) formed by dispersing in a binder (4)
It has been established.

The photoreceptor shown in FIG. 2 has a photosensitive layer (2b) provided on a conductive support by dispersing a bismeso ion compound (3) in a charge transport medium consisting of a charge transport substance (5) and a binder. . The photoreceptor shown in FIGS. 3 and 4 includes a charge carrier generating layer (6) mainly composed of a bismesoionic compound (3), a charge transport material and a binder. i!
A certain photosensitive layer (2C) or <2d> is provided from (7) and (7), respectively. In the case of FIG. 1, the bismesoionic compound (3) performs both the functions of generating charge carriers necessary for light attenuation and transporting charges. In the case of the photoreceptor of FIG. 2, the charge transport material together with the binder forms the charge transport medium (5), while the bismesoionic compound (3) acts as a charge carrier generating material. This charge transport medium (
Although 5) does not have the ability to generate charge carriers like the bismesoionic compound (3), it has the ability to accept and transport charge carriers generated from the bismesoionic compound. That is, in the photoreceptor of FIG. 2, the generation of charge carriers necessary for photoattenuation is carried out by the bismeso ion compound (3), while the transport of charge carriers is mainly carried out by the charge transport medium (5).
This is done by In the case of the photoreceptors shown in FIGS. 3 and 4, the bismesoionic compound (3) contained in the charge carrier generation layer (6) generates charge carriers, while the charge transport layer (7) generates charge carriers.
) receives injection of charge carriers and transports them. That is, the mechanism of action is the same as that of the photoreceptor shown in FIG. 2, in which the generation of charge carriers necessary for light attenuation is carried out by a bismeso ion compound, and the transport of charge carriers is carried out by a charge transport medium.

The photoreceptor shown in FIG. 1 is made by dispersing a bismeso ion compound in a binder solution, coating this dispersion on a conductive support,
It can be manufactured by drying. The photoreceptor shown in FIG. 2 can be manufactured by dispersing a bismeso ion compound in a solution containing a charge transporting substance and a binder, coating this dispersion on a conductive support, and drying it. The photoreceptor shown in FIG. 3 can be produced by vacuum-depositing a bismesoion compound on a conductive support, or by applying a dispersion obtained by dissolving fine particles of a bismesoion compound in a solvent or binder solution and drying it. It can be manufactured by applying a solution containing a charge transporting substance and a binder thereon and drying it. The photoreceptor shown in Fig. 4 is produced by coating a conductive support with a solution containing a charge transport substance and a binder and drying it, and then vacuum-depositing a bismesoion compound thereon, or by depositing fine particles of a bismesoion compound in a solvent or binder solution. It can be manufactured by applying and drying a dispersion obtained by dispersing the liquid into a liquid.

The thickness of the photosensitive layer of these photoreceptors is 3 to 50 μm, preferably 5 to 20 μm in the case of the photoreceptors shown in FIGS.
It is. In the case of the photoreceptor shown in FIGS. 3 and 4, the thickness of the charge carrier generation layer is 5 μm or less, preferably 0.01 to 5 μm.
2 μm, and the thickness of the charge transport layer is 3 to 50 μm, preferably 5 to 20 μm. In the photoreceptor shown in FIG. 1, the proportion of the bismeso ion compound in the photosensitive layer is 10 to 70% by weight, preferably 30 to 50% by weight, based on the photosensitive layer. In the photoreceptor shown in FIG. 2, the proportion of the bismeso ion compound in the photosensitive layer is 1 to 50% by weight, preferably 3 to 30% by weight, and the proportion of the charge transport substance is 10% by weight.
-90% by weight, preferably 10-60% by weight. The proportion of the charge transport substance in the charge transport medium in the photoreceptor of FIGS. 3 and 4 is 10 to 95%, preferably 10 to 95%.
It is 60% by weight.

Examples of the conductive support used in the photoreceptor of the present invention include aluminum, steel, zinc, stainless steel, chromium,
Metal plates or metal drums using metals or alloys such as titanium, nickel, molybdenum, vanadium, indium, gold, platinum, or conductive polymers, conductive compounds such as indium oxide, metals such as aluminum, palladium, gold, etc. Examples include paper coated with, vapor-deposited, or laminated with an alloy, and a plastic film.

As the binder, it is preferable to use a hydrophobic, electrically insulating, film-formable polymer. Examples of such high molecular weight polymers include polycarbonate,
Polyester, methacrylic resin, acrylic resin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride Examples include, but are not limited to, Ml combination, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinyl-rubazole, polyvinyl butyral, polyvinyl formal, polysulfone, etc. do not have.

These binders can be used alone or as a mixture of two or more.

Additionally, additives such as plasticizers, sensitizers, and surface modifiers can also be used together with these hinderers.

Examples of plasticizers include biphenyl, biphenyl chloride, 0-terphenyl, p-terphenyl, dibutyl phthalate, diethylene glycol phthalate, dioctyl phthalate, triphenyl phosphoric acid, methylnaphthalene, penzophenone, chlorinated paraffin, polypropylene, polystyrene, various fluorohydrocarbons, and the like. Can be mentioned.

Examples of the sensitizer include chloranil, tetracyanoethylene, methyl violet, rhodamine B1 cyanine dye, merocyanine dye, pyrylium dye, and thiavirylium dye.

Examples of the surface modifier include silicone oil, fluorine resin, and the like.

Furthermore, in the present invention, in order to improve the adhesion between the conductive support and the photosensitive layer and to prevent the injection of free charges from the conductive support to the photosensitive layer, Between,
An adhesive layer or barrier layer can also be provided if necessary. In addition to the polymer compounds used in the binder, materials used for these layers include casein, gelatin, polyvinyl alcohol, ethyl cellulose, nitrocellulose, polyvinyl butyral, phenolic resin, polyamide, carpoxymethyl cellulose, vinylidene chloride-based polymer latex. , styrene-butadiene polymer latex, polyurethane, gelatin, argonium oxide, tin oxide, titanium oxide, and the like.

In addition, charge transport materials are generally classified into two types: compounds that transport electrons and compounds that transport holes.
Both can be used in the electrophotographic photoreceptor of the present invention.

Examples of the electron transport substance include chloranil, promoanil, tetracyanoethylene, teracyanoquinodimethane, 2.4.7-1-linitro-9-fluorenone, and 2.4,5.7-tetranitro-9. - Fluorenone, 9-dicyanomethylene-2.4.7 - Trinitrofluorenone, 9-dicyanomethylene-2,4.5.
7-tetranitrofluorenone, 2,4,5.7tetranitroxanthone, 2.4.8-}linitrothioxanthone, tetranitrocarbazole chloranil, 2
．． 3-dichloro-5,6-dicyanobenzoquinone, 2.
Examples include 4.7-trinitro9.10-phenanthrenequinone and tetrachlorophthalic anhydride.

Examples of low-molecular-weight compounds as transport substances include birene, N-ethylcarbazole, N-isopropyrubazole, N-phenylcarbazole, or N-methyl-2-phenylhydrazino-3-methylidene-9. -Ethylcarbazole, N,N-diphenylhydrazino-
3-methylidene-9-ethylcarbazole, p-N. N
Hydrazones such as -dimethylaminobenzaldehyde diphenylhydrazone, p-N,N-diethylaminobenzaldehyde diphenylhydrazone, p-N,N-diphenylaminobenzaldehyde diphenylhydrazone [
, 2.5-bis(p-diethylaminophenyl)-1.
3.4-oxadiazole, ■-phenyl-3-(p-
Birazolines such as diethylaminostyryl)-5=(p-diethylaminophenyl)pyrazoline, triphenylamine, N,N,N',N'-tetraphenyl-
1.1'-biphenyl-4.4'diamine, N,N'-
Diphenyl-N,N'-bis(3-methylphenyl')
- 1,1'-biphenyl-4,4'-diaξene and the like. Further, examples of the polymer compound include poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, birene-formaldehyde resin, ethyl rubazole-formaldehyde resin,
Examples include triphenylmethane polymer.

The charge transport materials are not limited to those described here, and can be used alone or in combination of two or more kinds.

When forming a laminated photoreceptor by coating, the solvent that dissolves the binder varies depending on the type of binder, but is preferably selected from those that do not dissolve the lower layer. Specific examples of organic solvents include alcohols such as methanol, retanol, and n-probanol;
Ketones such as acetone, methyl ethyl ketone, cyclohexanone, etc.11. N,N-dimethylformamide, N,N-
Amides such as dimethylacetate; ethers such as tetrahydrofuran, dioxane, and methyl cellosolve; esters such as methyl acetate and ethyl acetate; sulfoxides and sulfones such as dimethyl sulfoxide and sulfolane;
Examples include aliphatic halogenated hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, and trichloroethane; and aromatics such as benzene, toluene, xylene, monochlorobenzene, and dichlorobenzene.

As the coating method, for example, a dip coating method, a spray coating method, a sinter coating method, a bead coating method, a wire bar coating method, a blade coating method, a roller coating method, a curtain coating method and the like can be used.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to Examples, but does this mean that the present invention is limited to the Examples? There isn't. still,
In the examples, "parts" indicate "parts by weight." In addition, the bismesoionic compound fish means the magnetic substance in Table 1.

Example 1 10 parts of a polyester resin (trade name "Vylon 200" manufactured by Toyobo Co., Ltd.), 10 parts of a bismethionic compound of Magnetic 1, and 80 parts of tetrahydrofuran were pulverized and mixed in a vibrating mill, and the resulting dispersion was deposited with aluminum. It was coated on a polyester film with a wire shear and dried to obtain a photoreceptor having the structure shown in FIG. 1 having a photosensitive layer with a thickness of about 10 μm. Next, an electrostatic copying paper testing device Model SP was applied to the photosensitive layer surface of this photoreceptor.
-428 (manufactured by Kawaguchi Denki Seisakusho Co., Ltd.), the photoreceptor was first charged in the dark by corona discharge with an applied voltage of -6 kV, left in the dark for 10 seconds, and then a tungsten lamp was used to charge the surface with an illumination intensity of 5 lux. The photosensitive layer is irradiated with light so that the photosensitive layer becomes
When I/t (Rusox seconds) was calculated, El/■=
1 6. It was 0 lux seconds.

Example 2 3 parts of polyester resin (same product as Example 1), 2, 4.
3 parts of 7-trinitol-9-fluorenone, 0.0 parts of bismesoionic compound of patient 1. 6 parts and 30 parts of tetrahydrofuran
The resulting dispersion was applied onto a polyester film coated with aluminum using a wire bar and dried to form a photosensitive layer with a thickness of approximately 9 μm as shown in Figure 2. The body was created. Next, the sensitivity of this photoreceptor was measured according to Example 1, and it was found to be E I/! = 3
．． It was 5 lux seconds.

Example 3 3 parts of a bismethionic compound of PkLl was ground and mixed in a solution in which 1 part of phenoxy resin (trade name rPKHI {manufactured by J Union Carbide) was dissolved in 75 parts of dioxane using a vibrating mill, and the resulting dispersion was prepared. was coated on an aluminum vapor-deposited polyester film using a wire bar and dried to form a charge generating layer with a thickness of lμ. A solution of 5 parts of p-diethylaminobenzaldehyde diphenylhydrazone and 5 parts of polycarbonate resin (trade name "Banrai" L-1250WJ manufactured by Teijin Kakaisha) dissolved in 65 parts of methylene chloride was placed on top of this charge generation layer using a wire bar. Coating and drying (7 to form a charge transport layer with a thickness of 10μ)
A photoreceptor having the structure shown in the figure was obtained. The sensitivity of the photoreceptor thus prepared was measured according to Example 1 and found to be E+zz=2.8.
It was a look second.

Examples 4 to 17 A photoreceptor having the structure shown in FIG. 3 was prepared in the same manner as in Example 3, except that the bismeso ion compounds shown in Table 2 below were used in place of the 11hl bismeso ion compound, and the photoreceptor was prepared in the same manner as in Example 1. The sensitivity was measured and the results listed in Table 2 were obtained.

Second table? Example 18 The structure shown in FIG. 3 was prepared in the same manner as in Example 3, except that N-ethyl rubazole-3-methylidene-N-aminoindoline was used instead of p-jethylaminobenzaldehyde diphenylhydrazone as the charge transport material. When a photoreceptor was prepared and its sensitivity was measured according to the example, El/
■ = 2.5 lux seconds.

Examples 19 to 32 The bismesoionic compounds shown in Table 3 below were used instead of the bismesoionic compound of NaI, and N-ethylcarbazole-3-methylidene-N was used instead of p-jethylaminobenzaldehyde diphenylhydrazone as the charge transport material. -Example 3 except that ξanoindoline was used
A photoreceptor having the structure shown in FIG. 3 was prepared in the same manner as in Example 1.
The sensitivity was measured according to the method and the results listed in Table 3 were obtained.

/ ◇Re' / / Table 3 Example 33 Same as Example 3 except that N-ethylcarbazole-3-methylidene-N-aminotetrahydroquinoline was used instead of p-diethylaminobenzaldehyde diphenylhydradun as the charge transport material. A photoreceptor having the structure shown in FIG. 3 was produced using the same method, and the sensitivity was measured according to Example 1, and the sensitivity was found to be El/Z=2.6 lux·sec.

Examples 34 to 47 Each of the bismesoionic compounds shown in Table 4 below was used in place of the bt bismesoionic compound, and N-ethyl Rubazole-3- was substituted for P-diethylanohenzaldehyde diphenylhydrazone as the charge transport material. A photoreceptor having the structure shown in Figure 3 was prepared in the same manner as in Example 3, except that methylidene-N-aminotetrahydroquinoline was used, and the sensitivity was measured in accordance with Example 1. The results are shown in Table 4. Obtained.

Table 4? Example 48 3 parts of polycarbonate resin (same product as Example 3), p-
A solution of 3 parts of diethylanobenzaldehyde diphenylhydrazone dissolved in 35 parts of tetrahydrofuran was applied onto an aluminum-deposited polyester film using a wire bar and dried to form a charge transport layer with a thickness of about 10 μm. .

Next, the paint used to form the charge generation layer in Example 3 was applied onto the charge transport layer using a wire bar and dried to form a charge generation layer with a thickness of about 0.8 μm. A photoreceptor was obtained. The sensitivity of the thus produced photoreceptor was measured according to Example 1 by performing corona discharge at an applied voltage of +6 kV, and found that El/■=3.0 lux·sec.

〔Effect of the invention〕

Since the electrophotographic photoreceptor of the present invention has excellent durability and high sensitivity, it can be widely used in 'PPC copying machines and the like.

[Brief explanation of drawings]

1 to 4 are enlarged partial cross-sectional views of the electrophotographic photoreceptor according to the present invention. 1... Conductive support, 2a, 2b, 2c, 2d-...
Photosensitive layer, 3... bismesoionic compound, 4... binder, 5... charge transport material, 6... charge carrier generation layer, 7... charge transport layer. agent

Claims (1)

[Claims] 1. The photosensitive layer has the general formula (I) ▲mathematical formula, chemical formula, table, etc.▼ (wherein A represents a phenylene group or a naphthylene group,
R represents a hydrocarbon group which may have a substituent or a heterocyclic group which may have a substituent. ) A photoreceptor for electrophotography, characterized in that it contains a compound represented by: