JPH02207266A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body having high sensitivity and high durability by incorporating a specified compd. CONSTITUTION:A compd. represented by formula I (where Cp is a residue of a coupler) is incorporated. The compd. can easily be produced by allowing m-nitrobenzaldehyde to react with dithiooxamide in N,N-dimethylacetamide under heating and refluxing, diazotizing produced 2,5-bis(3-nitrophenyl) thiazolo[4,5-d]thiazole and coupling the obtd. diazo compd. with the coupler Cp in the presence of alkali. An electrophotographic sensitive body having superior durability and high sensitivity is obtd.

Description

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

[Conventional technology]

The so-called electrophotographic method, in which images are recorded by combining a photoconductive substance and an electrostatic phenomenon, was developed by Carl Zuhl 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 (1) 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) Durability, low cost, etc. are required.

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 hengal, photobleaching of the dye due to corona charging can shorten the life of the photoreceptor. was. 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,
Electrophotographic photoreceptor consisting of poly-N-vinylcarbazole and 2.4.7-)linitrofluorenone (U.S. Pat. No. 3,484,237), poly-N-vinylcarbazole enhanced with pyrylium salt dye. What I felt (Tokuko Sho 4)
8-25658), and one in which a eutectic consisting of a dye and a resin is used as a photoconductive material (Japanese Patent Application Laid-open No. 10785/1982). Such an organic compound-based electrophotographic photoreceptor is
Compared to inorganic compound-based electrophotographic photoreceptors, it has the advantage that it is easier to form a film, has extremely high productivity, and can provide an inexpensive photoreceptor. However, for example, poly-
Regarding photoconductive polymers such as N-vinylcarbazole, the film properties, flexibility, and adhesive properties of the polymer alone are poor, so plasticizers, binders, etc. are added to improve these defects. However, this has led to problems such as a decrease in sensitivity and 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 adhesion, on the other hand, they do not fully meet 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, improve the drawbacks of organic compound-based electrophotographic photoreceptors that have been proposed so far, and put them into practical use. An object of the present invention is to provide an electrophotographic photoreceptor having extremely high sensitivity and durability.

[Failure to solve the problem]

In order to solve the above problems, the present invention provides an electrophotographic photoreceptor containing a compound represented by formula (I) (wherein Cp represents a coupler residue).

The coupler residue in the compound represented by the general formula (I) can be selected from known coupler components, but in particular - formula (II) - formula (III) general formula (IV) [Jll or - Numerical formula (V) (wherein, X represents a hydrocarbon ring or heterocycle which may have a substituent, Y is a hydrogen atom, R2 and R3 each independently have a hydrogen atom or a substituent) R1 and R2 may mutually form a ring.) The coupler residue represented by the following formula is preferable.

Specific examples of RI, R2 and R3 in the coupler residues of formulas (n), (III), (IV) and (V) above include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, group, isopropyl group, isoamyl group, isoamyl group, isohexyl group, neopentyl group, t
Alkyl groups having 1 to 20 carbon atoms such as er t-butyl group; aromatic hydrocarbon groups such as phenyl group and naphthyl group; aromatic heterocyclic groups such as pyridyl group, carbazolyl group, benzotriazolyl group, etc. Can be mentioned.

When R1, Rz and R3 are substituted alkyl groups, examples of the substituent include a halogen atom, a nitro atom, a cyano group, a hydroxyl group, a substituted hydroxyl group, a thiol group, a substituted thiol group, an amino group, a substituted amino group, Examples include aryl groups.

It may be a substituted alkyl group having two or more of these substituents. Specific examples of substituted alkyl groups include halogenoalkyl groups such as chloromethyl group, trifluoromethyl group, and 2-bromoethyl group; nitroalkyl groups such as nitromethyl group and 3-nitropropyl group; cyanomethyl group, 2-bromoethyl group;
- cyanoalkyl group such as cyanoethyl group; hydroxyalkyl group such as hydroxymethyl group, 2-hydroxyethyl group, 2-hydroxypropyl group, 3-hydroxypropyl group; methoxymethyl group, 2-methoxyethyl group, ethoxymethyl group, Substituted hydroxyalkyl groups such as phenoxymethyl group; thiohydroxyalkyl groups such as thiohydroxymethyl group and 2-thiohydroxyethyl group; substituted thiohydroxyalkyl groups such as methylthiomethyl group and 2-methylthioethyl group; aminomethyl group, 2 −
Aminoalkyl groups such as aminoethyl group; substituted aminoalkyl groups such as methylaminomethyl group, ethylaminomethyl group, dimethylaminomethyl group, 2-(dimethylamino)ethyl group, phenylaminomethyl group, diphenylamizmedel group, etc. can be mentioned.

When R1, R2 and R3 are a substituted aromatic hydrocarbon group or a substituted aromatic heterocyclic group, examples of the substituent include an alkyl group, a halogen atom, a 21·4 group, a cyano group, a hydroxyl group, a substituted hydroxyl group, Examples include a thiol group, a substituted thiol group, an amino group, and a substituted amino group. It may be a substituted aromatic hydrocarbon group or a substituted aromatic heterocyclic group having two or more of these substituents.

Specific examples when RI, R2 and R3 are substituted phenyl groups include alkylphenyl groups such as tolyl group and ethylphenyl group; halogen-substituted phenyl groups such as chlorophenyl group and bromophenyl group; nitrophenyl group; cyanophenyl M ; HyF-roxyphenyl group; substituted hydroxyphenyl group such as methoxyphenyl group and ethoxyphenyl group; thiohydroxyphenyl group; substituted thiophenyl group such as methylthiophenyl group and ethylthiophenyl group; aminophenyl group: methylaminophenyl group; Examples include substituted aminophenyl groups such as dimethylaminophenyl group, phenylaminophenyl group, and diphenylaminophenyl group.

Specific examples when R1, R2 and R3 are substituted condensed aromatic hydrocarbon groups include alkylnaphthyl groups such as methylnaphthyl group and ethylnaphthyl group; chloronaphthyl group;
Halogen-substituted naphthyl groups such as bromonaphthyl groups; hydroxynaphthyl groups; substituted hydroxynaphthyl groups such as methoxynaphthyl groups and ethylnaphthyl groups; thiohydroxynaphthyl groups; substituted thionaphthyl groups such as methylthionaphthyl groups and ethylthionaphthyl groups; aminonaphthyl groups Examples include substituted aminonaphthyl groups such as methylaminonaphthyl group, dimethylaminonaphthyl group, phenylaminonaphthyl group, and diphenylaminonaphthyl group.

Specific examples when R1, RZ and R3 are substituted aromatic heterocyclic groups, particularly substituted benzothiazolyl groups, include alkylhendithiazolyl groups such as methylbenzothiazolyl group and ethylbenzothiazolyl group; Halogen-substituted hendithiazolyl groups such as thiazolyl group and promobenzothiazolyl group; nitrobenzothiazolyl group; cyanohenzothiazolyl group; hydroxyhenzothiazolyl group; methoxybenzothiazolyl group, ethylbenzothiazolyl group Substituted hydroxyhendithiazolyl group such as a hydroxyl group; thiohydroxybenzthiazolyl group; substituted thiohendithiazolyl group such as methylthiohendithiazolyl group, ethylthiobenzothiazolyl group; aminohendithiazolyl group Examples include substituted aminohendithiazolyl groups such as methylaminohendithiazolyl group, dimethylaminobenzothiazolyl group, phenylaminohendithiazolyl group, and diphenylaminobenzothiazolyl group.

The disazo compound represented by the general formula (I) according to the present invention can be produced by a conventionally known method. for example,
As described in [Journal of Heterocyclic Chemistry] Volume 2, Page 441 (1965), m
- Nitrohenzaldehyde and dithiooxamide, N
, 2,5- represented by the following formula (VI) by reacting in N-dimethylacetamide under heating reflux.
Bis(3-2l-lophenyl)thiazolo(4,5-d)
Manufacture thiazole.

Further, the compound of formula (Vl) is reduced with zinc in ethanol in the presence of calcium chloride to produce a diamine derivative represented by the following formula (■).

Next, the compound represented by the formula (■) is diazotized by a conventional method and coupled with the coupler Cp in the presence of an alkali, or the diazonium salt of the compound represented by the formula (■) is converted into a borohydrofluoride or a zinc salt. Once isolated as a salt, it can be washed with an inert solvent such as a suitable solvent such as N,N'-dimethylformamide, dimethyl sulfoxide, etc.
? The compound of formula (1) can be easily produced by coupling with a coupler in a 9 medium in the presence of an alkali.

Specific examples of the disazo compounds of formula (I) that can be used in the present invention are shown in Tables 1 to 6 as structural formulas.

/ The electrophotographic photoreceptor of the present invention can have various structures. Examples are shown in Figures 1-4. The photoreceptor shown in FIG. 1 has a photosensitive layer (2a) formed by dispersing a disazo compound (3) in a binder (4) on a conductive support (1). The photoreceptor shown in FIG. 2 has a photosensitive layer (2b
). The photoreceptor shown in FIGS. 3 and 4 has a charge carrier generation layer (6) mainly composed of a disazo compound (3).
and a charge transport layer (7) consisting of a charge transport substance and a binder.
) and a photosensitive layer (2C) or (2d), respectively. In the case of Figure 1, a disazo 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 disazo compound (3) acts as a charge carrier generating material. Although this charge transport medium (5) does not have the ability to generate charge carriers like the disazo compound (3), it has the ability to accept and transport charge carriers generated from the disazo compound. That is, in the photoreceptor of FIG. 2, the generation of charge carriers necessary for light attenuation is performed by the disazo compound (3), while the transport of charge carriers is mainly performed by the charge transport medium (5). In the case of the photoreceptors shown in Figures 3 and 4, the disazo compound (3) contained in the charge carrier generation layer (6) generates charge carriers, while the charge transport layer (7) injects charge carriers. and transport it.

That is, the mechanism of action is the same as in the case of the photoreceptor shown in FIG. 2, in that charge carriers necessary for light attenuation are generated by a disazo compound, and charge carriers are transported by a charge transport medium.

The photoreceptor shown in FIG. 1 can be manufactured by dispersing a disazo compound in a binder solution, coating this dispersion on a conductive support, and drying it. The photoreceptor shown in FIG. 2 can be manufactured by dispersing a disazo 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 obtained by vacuum-depositing a disazo compound on a conductive support, or by applying a dispersion obtained by dispersing fine particles of a disazo compound in a solvent or binder solution, and drying the disazo compound. 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 disazo compound thereon, or by depositing fine particles of a disazo 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 disazo 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 disazo compound in the photosensitive layer is 1 to 50% by weight, preferably 3 to 30% by weight, and the proportion of the charge transport material is 10 to 90% by weight.
, preferably 10 to 60% by weight. Figures 3 and 4
The proportion of the charge transport material in the charge transport medium in the illustrated photoreceptor is 10 to 95%, preferably 10 to 60%.

Examples of the conductive support used in the photoreceptor of the present invention include aluminum, copper, zinc, stainless steel, chromium,
Metal plates or metal drums made of metals or alloys such as titanium, nickel, molybdenum, vanadium, syndium, 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, a plastic film, and the like.

As the binder, it is preferable to use a hydrophobic polymer capable of forming an electrically insulating film. 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, acid copolymers, silicone resins, silicone alkyd resins, phenol-formaldehyde resins, styrene-alkyd resins, poly-N-vinylcarbazole, polyvinyl butyral, polyvinyl formal, polysulfone, etc. isn't it.

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

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

Examples of plasticizers include biphenyl, chlorinated biphenyl, 0-terphenyl, p-terphenyl, dibutyl tuclate, diethylene glycol phthalate, dioctyl tuclate, triphenyl phosphoric acid, methylnaphthalene, benzophenone chlorinated paraffin, polypropylene, polystyrene, and various other plasticizers. Examples include fluorohydrocarbons.

Examples of the sensitizer include chloranil, tetracyanoethylene, methyl violet, rhodamine B, cyanine dye, merocyanine dye, biryllium dye, and thiapyrylium dye.

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

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 as required. Materials used for these layers include, in addition to the polymer compounds used in the binder, casein, gelatin, polyvinyl alcohol, ethyl cellulose, nitrocellulose, polyvinyl butyral, phenolic resin, polyamide, carpoxy-methylcellulose vinylidene chloride, etc. Examples include polymer latex, styrene-butadiene polymer latex, polyurethane, gelatin, aluminum oxide, tin oxide, and titanium oxide.

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 charge transport substance include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4.7-1-dinitro-9-fluorenone, 2
, 4,5.7-tetranitro-9-fluorenone, 9-
Dicyanomethylene-2,4,7-trinitrofluorenone, 9-dicyanomethylene-2゜4.5.7-tetranitrofluorenone, 2,4,5.7-tetranitroxanthone, 2,4.8-)linitro Thioxanthone, tetranitrocarbazole chloranil, 2,3-dichloro-
Examples include 5,6-dicyanobenzoquinone, 2,4,7-dolinitro-9,10-phenanthrenequinone, and tetrachlorophthalic anhydride.

Examples of the hole transport substance include low molecular weight compounds such as pyrene, N-ethylcarbazole, N-isopropylcarbazole, N-phenylcarbazole, or N-methyl-2-phenylhydrazino-3-methylidene-9-ethyl. Carbazole, N,N-diphenylhydrazino-3
-Methylidene 9-ethylcarbazole, p-N,N-dimethylaminobenzaldehyde diphenylhydrazone,
Hydrazones such as pN, N-dimethylaminobenzaldehyde diphenylhydrazone, p-N, N-diphenylaminobenzaldehyde diphenylhydrazone, 2,5
-bis(P-diethylaminophenyl)-L3,4-oxadiazole, ■-phenyl-3-(P-diethylaminophenyl)-5(p-diethylaminophenyl)pyrazoline, etc., triphenylamine, N,
N,N',N'tetraphenyl-1,1'-biphenyl-4,4'diamine, N,N'-diphenyl-N,N
'-bis(3-methylphenyl)-CI'-biphenyl 4,4'-diamine and the like. Examples of polymer compounds include poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, pyrene-formaldehyde resin, ethylcarbazole-formaldehyde resin, and triphenylmethane polymer. etc.

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. Examples of specific organic solvents include alcohols such as methanol, ethanol, and n-propanol; ketones such as acetone, methyl ethyl ketone, and cyclohexanone, and amides such as N, N-dimethylformamide, and N,N-dimethylacetamide. ;Tetrahydrofuran,
Ethers such as dioxane and methyl cellosolve; Esters such as methyl acetate and ethyl acetate; Sulfoxides and sulfones such as dimethyl sulfoxide and sulfolane; Aliphatic halogens (IJ hydrogen hydride; Examples include aromatic compounds such as henzene, toluene, xylene, monochlorohensen, and dichlorohensen.

As the coating method, coating methods such as dip coating, spray coating, spinner coating, bead coating, wire bar coating, blade coating, roller coating, and curtain coating can be used.

〔Example〕

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to the Examples. still,
In the examples, "parts" indicate "parts by weight." Further, the number of the disazo compound means the number in Tables 1 to 6.

Example 1 10 parts of a polyester resin (trade name "Vylon 200" manufactured by Toyobo Co., Ltd.), 10 parts of disazo compound No. 1, and 80 parts of tetrahydrofuran were pulverized and mixed in a vibrating mill, and the resulting dispersion was made into a polyester coated with aluminum. It was coated on a film with a wire bar 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 Electric Seisakusho Co., Ltd.), the photoreceptor was first charged in a dark place by corona discharge with an applied voltage of -6 kV, left in the dark for 10 seconds, and then its surface was illuminated with an illuminance of 5 lux from a tungsten lamp. The photosensitive layer was irradiated with light, and the time required for its surface potential to decrease to 172, which is the surface potential after being left in a dark place for 10 seconds, was measured.
When the photosensitivity El/□ (lux/second) was calculated, E
l/□-23,0 lux·sec.

Example 2 3 parts of polyester resin (same product as Example 1), 2.4.
3 parts of 7-1-dinitro-9-fluor 12F, N.

0.6 part of the disazo compound of ■ and 3 parts of tetrahydrofuran
0 parts were pulverized and mixed in a ball mill, and the resulting dispersion was coated on a polyester film coated with aluminum using a wire bar and dried to produce a photoreceptor having the structure shown in Figure 2, having a photosensitive layer with a thickness of about 9μ. was created. Next, the sensitivity of this photoreceptor was measured according to Example 1 and found to be El/□-2, flux seconds.

Example 3 3 parts of the disazo compound No. 1 was pulverized and mixed in a solution prepared by dissolving 1 part of phenoxy resin (product name: rPKIIHJ Union Carbide Co., Ltd.) in 75 parts of dioxane using a vibration mill, and the resulting dispersion was obtained. 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 1 μm. A solution of 5 parts of p-diethylaminobenzaldehyde-diphenylhydrazone and 5 parts of polycarbonate resin (trade name [Panlite L-1250W manufactured by J Kijin Kasei Co., Ltd.) dissolved in 65 parts of methylene chloride was placed on top of this charge generation layer using a wire bar. A charge transport layer having a thickness of 10 μm was formed by coating and drying to obtain a photoreceptor having the structure shown in FIG. The sensitivity of the thus produced photoreceptor was measured according to Example 1 and was found to be El/□-2,4 lux·sec.

Examples 4 to 2 A photoreceptor having the structure shown in FIG. 3 was prepared in the same manner as in Example 3 except that the disazo compounds shown in Table 7 below were used in place of the disazo compounds in No. 1. Sensitivity was measured according to the method and the results listed in the same table were obtained.

Example 21 A photoreceptor having the structure shown in FIG. 3 was prepared in the same manner as in Example 3 except that N-ethylcarbazole-3-methylidene-N-aminoindoline was used instead of p-diethylaminobenzaldehyde-diphenylhydrazone as the charge transport material. When the sensitivity was measured according to Example 1, E.
/z = 2.8 lux·sec.

Examples 22-4O The disazo compounds shown in Table 8 below were used instead of the disazo compounds No. and I, and N-ethylcarbazole 3-methylidene-N~ was used instead of p-diethylaminobenzaldehyde-diphenylhydrazone as the charge transport substance.
A photoreceptor having the structure shown in FIG. 3 was prepared in the same manner as in Example 3 except that ruminoindoline was used, and the sensitivity was measured in accordance with Example 1 to obtain the results listed in Table 8.

Example 41 A photoreceptor having the structure shown in FIG. 3 was prepared in the same manner as in Example 3, except that N-ethylcarbazole-3-methylidene-N-aminotetrahydroquinoline was used instead of p-diethylaminobenzaldehyde-diphenylhydrazone as the charge transport material. was prepared and the sensitivity was measured according to Example 1, and it was found to be El/. -2.4 lux·sec.

Examples 42 to 6O In place of the disazo compound in No. 1, the disazo compounds listed in Table 9 below were used, and as the charge transport material, N-ethylcarbazole 3-methylidene was used instead of p-stylaminobenzaldehyde-diphenylhydrazone. N-
A photoreceptor having the structure shown in FIG. 3 was prepared in the same manner as in Example 3, except that aminotetrahydroquinoline was used, and the sensitivity was measured in accordance with Example 1, and the results listed in the table were obtained.

Table 9 Example 61 3 parts of polycarbonate resin (same product as Example 3), p-
A solution prepared by dissolving 3 parts of diethylaminobenzaldehyde-diphenylhydrazone in 35 parts of tetrahydrofuran was coated on a polyester film coated with aluminum using a wire bar and dried to form a charge transport layer with a thickness of about 10 microns.

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 prepared photoreceptor was measured according to Example 1 by performing corona discharge at an applied voltage of +6 kV, and found that E I/□ = 2.5 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 RPC copying machines and the like.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 4 are enlarged partial cross-sectional views of an electrophotographic photoreceptor according to the present invention. ■... Conductive support, 2a, 2b, 2c, 2d-photosensitive layer, 3... Disazo compound, 4... Binder, 5
... Charge transport material, 6... Charge carrier generation layer, 7...
・Charge transport layer.

Claims (1)

[Claims] 1. Electrophotography characterized by containing a compound represented by the general formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, Cp represents a coupler residue.) Photoreceptor for use. 2. Cp is general formula (II) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ General formula (III) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ General formula (IV) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or General formula (V) ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, X represents a hydrocarbon ring or heterocycle that may have a substituent, Y is a hydrogen atom, ▲ Numerical formula, chemical formula ,
There are tables, etc.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and R^1, R^2, and R^3 are each independently a hydrogen atom or a hydrocarbon group that may have a substituent. or represents a heterocyclic group, R^
1 and R^2 may mutually form a ring. ) The electrophotographic photoreceptor according to claim 1, which is a coupler residue represented by the following formula.