JPH02208657A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the electrophotographic sensitive body having the high sensitivity sufficient for practicable use and high durability by incorporating a specific compd. into the above-mentioned body. CONSTITUTION:This photosensitive body is constituted by providing a photosensitive layer 2a dispersed with a disazo compd. 3 in a binder 4 onto a conductive base 1. A photosensitive layer 2b formed by dispersing the disazo compd. 3 into a charge transfer medium consisting of a charge transfer material 5 and a binder is otherwise provided on the conductive base. The compd. expressed by the formula is incorporated into such photosensitive body. In the formula, Cp denotes a residual coupler group. The excellent durability and the high sensitivity are obtd. in this way and, therefore, this photosensitive body is widely usable as a PPC copying machine, etc.

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 (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 because it is sensitized with dyes such as rose bengal, photobleaching of the dye due to corona charging can shorten the life of the photoreceptor. 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,
Poly-N-vinyl Carbashield 2.4. T-) linitrofluorenone (U.S. Pat. No. 3,484,237), poly-N-vinylcarbazole sensitized with pyrylium salt dye (Japanese Patent Publication No. 4)
B-25658), a photoconductive material using a eutectic consisting of a dye and a resin (Japanese Unexamined Patent Publication No. 10785/1983)
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 film properties, flexibility, adhesion, etc., and in order to improve these drawbacks, plasticizers and binders are used. etc. are added, but this may cause a decrease in sensitivity,
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, 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.

[Means to solve the problem]

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

The coupler residue in the compound represented by general formula (I) can be selected from known coupler components, but in particular general formula (n) general formula (I) general formula (IV) R″ υN or General formula (V) (wherein, X may have a substituent) represents a hydrocarbon ring or a heterocycle, Y is a hydrogen atom, Rz and R3 each independently represent a hydrogen atom, a substituent (represents a hydrocarbon group or a heterocyclic group which may have R1 and R1 may mutually form a ring) is preferably a coupler residue represented by the following.

The above general formulas (n), (, II[), (rV) and (V)
R1. in the coupler residue of Specific examples of R1 and R3 include methyl group, ethyl group, propyl group, butyl group,
Pentyl group, hexyl group, isopropyl group, isobutyl group, isoamyl group, isohexyl group, neopentyl group,
Examples include alkyl groups having 1 to 20 carbon atoms such as tart-butyl group; aromatic hydrocarbon groups such as phenyl group and naphthyl group; aromatic heterocyclic groups such as pyridyl group, carbazolyl group, and benzotriazolyl group. It will be done.

When R1, R1 and R'' are substituted alkyl groups, the substituents include, for example, 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. , aryl group, etc.

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, diphenylaminomethyl group, etc. Can be mentioned.

When R', R'' 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 nitro group, a cyano group, a hydroxyl group, a substituted hydroxyl group, and a thiol group. group, substituted thiol group,
Examples include amino groups, substituted amino groups, and the like. 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 group. ; Hydroxyphenyl 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 dimethylaminophenyl group, dimethylaminophenyl group group, phenylaminophenyl group,
Examples include substituted aminophenyl groups such as diphenylaminophenyl groups.

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

Specific examples when R1, R1 and R3 are substituted aromatic heterocyclic groups, particularly substituted benzothiazolyl groups, include alkylbenzothiazolyl groups such as methylbenzothiazolyl group and ethylbenzothiazolyl group; chlorobenzo Halogen-substituted benzothiazolyl groups such as thiazolyl group and bromobenzothiazolyl group; nitrobenzothiazolyl group didianobenzothiazolyl group; hydroxybenzothiazolyl group; methoxybenzothiazolyl group, ethoxybenzothiazolyl group Substituted hydroxybenzothiazolyl group such as ethylthiobenzothiazolyl group; Thiohydroxybenzothiazolyl group; Substituted thiobenzothiazolyl group such as methylthiobenzothiazolyl group, ethylthiobenzothiazolyl group; Aminobenzothiazolyl group Examples include substituted aminobenzothiazolyl groups such as methylaminohendithiazolyl group, dimethylaminobenzothiazolyl group, phenylaminobenzothiazolyl 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,
Using fluorene as a raw material, 3,7 diaminofluorenone represented by the following formula (VI) is produced by the following method.

Next, the compound represented by the formula (Vl) is diazotized by a conventional method and coupled with the coupler Cρ in the presence of an alkali, or the diazonium salt of the compound represented by the formula (Vl) is converted into a borohydrofluoride or a zinc salt. Once isolated as a salt, compounds of formula (I) can be readily prepared by coupling with a coupler in the presence of an alkali in a suitable solvent, e.g., an inert organic solvent such as N,N'-dimethylformamide, dimethyl sulfoxide, etc. compounds can be manufactured.

Specific examples of the disazo compounds of the general 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 (I). 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) is responsible for the generation of charge carriers necessary for light attenuation and for the charge transport. 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. Further, 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 charge transport material in the charge transport medium in the illustrated photoreceptor is 10 to 95%, preferably 10 to 60% by weight.

Examples of the conductive support used in the photoreceptor of the present invention include aluminum, copper, zinc, stainless steel, chromium,
Metal plates and metal drums made of metals or alloys such as titanium, nickel, molybdenum, vanadium, syndium, gold, and platinum, or conductive polymers, conductive compounds such as indium oxide, aluminum, platinum, gold, etc. Examples include paper coated, vapor-deposited, or laminated with metal or alloy, 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 a polymer 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 copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly-N-vinylcarbazole, polyvinyl butyral, polyvinyl formal , polysulfone, etc., but are not limited to these.

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 phthalate, diethylene glycol phthalate, dioctyl phthalate, triphenyl phosphoric acid, methylnaphthalene, benzophenone chlorinated paraffin, polypropylene, polystyrene, and various fluorocarbons. Examples include hydrogen.

Examples of the sensitizer include chloranil, tetracyanoethylene, methyl violet, rhodamine B5 cyanine dye, merocyanine dye, pyrylium 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 if necessary. Materials used for these layers include, in addition to the polymer compound used for the binder, casein,
Gelatin, polyvinyl alcohol, ethyl cellulose,
Examples include nitrocellulose, polyvinyl butyral, phenolic resin, polyamide, carboxymethylcellulose vinylidene chloride polymer latex, styrene-butadiene polymer latex, polyurethane, gelatin, aluminum 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 charge transport substance include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2.4.7-) 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-) Nitrothioxanthone, tetranitrocarbazole chloranil, 2,3-dichloro-5,6-dicyanobenzoquinone, 2.4.7-) dinitro-9,1O-phenanthrenequinone, tetrachlorophthalic anhydride, etc. may be mentioned. .

Examples of the hole transport substance include low molecular compounds such as evapyrene, N-ethylcarbazole, N-isopropylcarbazole, N-phenylcarbazole, or N-methyl-2-phenylhydrazino-3-methylidene-9-ethylcarbazole. , N,N-diphenylhydrazino-3
-Methylidene 9-ethylcarbazole, p-N,N-dimethylaminobenzaldehyde diphenylhydrazone,
hydrazone IN such as pN,N-diethylaminobenzaldehyde diphenylhydrazone, p-N,N-diphenylaminobenzaldehyde diphenylhydrazone;2.
5-bis(p-diethylaminophenyl)-1,3,4
-oxadiazole, pyrazolines such as -phenyl-3-(p-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'-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. Specific examples of organic solvents include alcohols such as methanol, ethanol, and n-propanol;
Ketones such as acetone, methyl ethyl ketone, and cyclohexanone; amides such as N,N-dimethylformamide and N,N-dimethylacetamide; ethers such as tetrahydrofuran, dioxane, and methyl cellosolve; esters such as methyl acetate and ethyl acetate; dimethyl Examples include sulfoxides and sulfones such as sulfoxide and sulfolane; aliphatic halogenated hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, and trichloroethane; aromatics such as benzene, toluene, xylene, monochlorobenzene, and dichlorobenzene. .

As a coating method, for example, a dip coating method, a spray coating method, a spinner coach ink method, a bead coating method, a wire bar coating method, a blade coating method, a roller coating method, a curtain coating method, or the like 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, "1 part" indicates "part by weight." Moreover, the floor of the disazo compound means the devil 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 a disazo compound of Nal, and 80 parts of tetrahydrofuran were pulverized and mixed in a vibrating mill, and the resulting dispersion was coated on a polyester film coated with aluminum. The photoreceptor was coated with a wire bar and dried to obtain a photoreceptor having the structure shown in FIG. 1 and having a photoreceptor layer with a thickness of about 10 μm. Next, an electrostatic copying paper tester Model 5P-4 was applied to the photosensitive layer surface of this photoreceptor.
28 (manufactured by Kawaguchi Denki Seisakusho Co., Ltd.), the photoreceptor was first charged by corona discharge at an applied voltage of -6 kV in a dark place, and 1
Leave it in the dark for 0 seconds, then turn on the tungsten lamp.
The photosensitive layer is irradiated with light so that the surface has an illuminance of 5 lux, and the time required for the surface potential to decrease to 1/2 of the surface potential after leaving it in the dark for 10 seconds is measured, and the photosensitivity El
/! When I calculated (looks/second), El/□=
It was 18.0 lux·sec.

Example 2 3 parts of polyester resin (same product as Example 1), 2.4.
7- 3 parts of trinitro-9-fluorenone, 0.6 parts of the disazo compound of Sou 1, and 30 parts of tetrahydrofuran were pulverized and mixed in a ball mill, and the resulting dispersion was spread on a polyester film coated with aluminum using a wire bar. A photoreceptor having the structure shown in FIG. 2 was prepared by coating and drying and having a photosensitive layer with a thickness of about 9 μm.The sensitivity of this photoreceptor was measured in accordance with Example 1 and found that E r/l = 3.2. It was Lutx Sec.

Example 3 3 parts of kl disazo compound was added to phenoxy resin (trade name '
1 part of PK Old 1 (manufactured by Union Carbide) was dissolved in 75 parts of dioxane and mixed by pulverization using a vibrating mill. The resulting dispersion was coated onto an aluminum-deposited polyester film using a wire bar and dried. A charge generation layer having a thickness of 1 μm was formed. On this charge generation layer, 5 parts of p-diethylaminobenzaldehyde-diphenylhydrazone and a polycarbonate resin (trade name "Panlite L-
1250W, manufactured by Kijin Kasei) 5 parts methylene chloride 65
A solution dissolved in the photoreceptor was coated using a wire bar and dried to form a charge transport layer having a thickness of 10μ, thereby obtaining a photoreceptor having the structure shown in FIG. The sensitivity of the photoreceptor thus produced was measured according to Example 1 and found to be E+zz=2.5 lux·sec.

Examples 4 to 20 Photoreceptors having the structure shown in FIG. 3 were 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 Sou 1, and the photoreceptors were prepared in accordance with Example 1. The sensitivity was measured and the results listed in the same table were obtained.

Table 7 Example 21 The structure shown in FIG. 3 was prepared in the same manner as in Example 3 except that N-ethylcarbazole-3-methylidene-N-ruaminoindoline was used instead of p-diethylaminobenzaldehyde-diphenylhydrazone as the charge transport substance. A photoreceptor was prepared and its sensitivity was measured according to Example 1.
/□=2.4 lux·sec.

Examples 22 to 40 Disazo compounds shown in Table 8 below were used in place of the disazo compound in Sou 1, and N-ethylcarbazole-3-methylidene-N- was used in place of p-diethylaminobenzaldehyde-diphenylhydrazone as the charge transport substance. The third step was carried out in the same manner as in Example 3 except that aminoindoline was used.
A photoreceptor having the structure shown in the figure was prepared, and the sensitivity was measured according to Example 1, and the results listed in Table 8 were obtained.

7/ / Example 41 The structure shown in Figure 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. A photoreceptor was prepared, and the sensitivity was measured according to Example 1, and the sensitivity was found to be El/l''2.5 lux·sec.

Examples 42 to 60 Disazo compounds shown in Table 9 below were used in place of the disazo compound in Sou 1, and N-ethylcarbazole-3-methylidene-N- was used in place 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 aminotetrahydroquinoline was used, and the sensitivity was measured in accordance with Example 1, and the results listed in the table were obtained.

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 El/! =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 PPC copying machines and the like.

[Brief explanation of the drawing]

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... 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.