JPH07271066A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic photoreceptor having high sensitivity, less liable to a change of potential by electrification or a change of residual potential and excellent in repetitive characteristics in an environment at low temp. and humidity when it is repeatedly used in an electrophotographic process. CONSTITUTION:In this electrophotographic photoreceptor with a photosensitive layer contg. at least an electric charge generating agent and an electric charge transferring agent on the electric conductive substrate, the photosensitive layer contains an indole compd. represented by formula I as the electric charge generating agent and a bisazo compd. represented by formula II as the electric charge transferring agent. In the formula I, R<1> is H, alkyl, alkenyl, aryl, alkoxyl or a heterocyclic group, R<2> is H, alkyl, alkenyl, aryl or a heterocyclic group, R<3> is alkylene or arylene and each of R<4> and R<5> is H, alkyl or aryl. In the formula II, A is H, alkyl, aryl or a heterocyclic group, each of (m) and (n) is 0 or 1 and B is a residue of a coupler.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoconductor, and more particularly, to an electrophotographic photoconductor having high sensitivity and small change in repetitive charging characteristics and residual potential, especially in a low temperature and low humidity environment. It is about.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic photosensitive member,
Those having a photosensitive layer containing an inorganic photoconductor as a main component such as selenium, cadmium sulfide, zinc oxide, and silicon have been widely known. However, they are sensitive, heat stable, moisture resistant,
Durability and the like are not always satisfactory, and particularly selenium and cadmium sulfide have been limited in production and handling due to their toxicity.

On the other hand, an electrophotographic photosensitive member having a photosensitive layer containing an organic photoconductive compound as a main component is relatively easy to manufacture, inexpensive, and easy to handle.
Further, it generally has many advantages such as excellent thermal stability as compared with the selenium photoconductor, and has been attracting much attention in recent years.

As such an organic photoconductive compound,
Poly-N-vinylcarbazole is well known, and an electrophotographic photosensitive material having a photosensitive layer containing as a main component a charge transfer complex formed from this and a Lewis acid such as 2,4,7-trinitro-9-fluorenone. The body is special Japanese Sho 50-10496
It is described in Japanese Patent Publication No. However, this photoreceptor was not always satisfactory in sensitivity, film-forming property and durability.

On the other hand, an electrophotographic photosensitive material containing a low molecular weight organic photoconductive compound in which a charge transfer agent typified by triphenylamines, stilbenes and hydrazones and a charge generating agent such as phthalocyanine and an azo pigment are combined. The body is proposed. By combining these with an appropriate binder, and further combining a compound having a high charge generation ability and a compound having a high charge transfer ability, for example, as a layered type photoreceptor, a compound having a sensitivity close to that of an inorganic photoreceptor such as selenium has appeared. There is. As a result, in the field of copying machines, printers, etc., photoconductors containing such an organic photoconductive compound as a main component have made great progress.

The laminated or dispersed function-separated type photoconductor in which the charge generation function and the charge transfer function are shared by different substances has a wide selection range of each material, and the charging characteristics, sensitivity and durability are large. It has an advantage that an electrophotographic photosensitive member having arbitrary characteristics in terms of electrophotographic characteristics can be prepared relatively easily.

Conventionally, various types of charge generating agents or charge transfer agents have been proposed. For example, an electrophotographic photoreceptor having a photosensitive layer in which a charge generation layer made of amorphous selenium and a charge transfer layer containing poly-N-vinylcarbazole as a main component are combined has been put into practical use. However, the charge generation layer made of amorphous selenium has a drawback of poor durability. Various proposals have been made to use an organic dye or organic pigment as a charge generating agent. For example, as an electrophotographic photoreceptor containing a monoazo pigment or a bisazo pigment in a photosensitive layer, Japanese Patent Publication No. 48-30513, Japanese Unexamined Patent Publication No. 52-41241, Japanese Unexamined Patent Publication No. 54-46558, Japanese Unexamined Patent Publication No. 56-11945 and the like are already known.

However, there are very few practically used function-separated type photoreceptors, and many required characteristics such as charging characteristics, sensitivity, residual potential, pre-exposure characteristics, and repetitive use characteristics. It is difficult to say that we are satisfied with everything. It can be said that these characteristics depend largely on the performance of each of the charge generating agent and the charge transfer agent, but it is also known that the selection of a suitable combination thereof is important, and many combinations have been proposed. ing. The reason seems to be that such selection is made by trial and error rather than being based on theoretical grounds.

[0009]

DISCLOSURE OF THE INVENTION The object of the present invention is to provide high sensitivity, small change in charging potential and residual potential, and stability in repeated use in an electrophotographic process, especially in a low temperature and low humidity environment. To provide an excellent electrophotographic photoreceptor.

[0010]

The present inventor has conducted extensive studies in order to achieve the above object, and as a result, in an electrophotographic photoreceptor, the indole compound represented by the structural formula 1 was contained in the photosensitive layer. The present invention has been found to be effective and has led to the present invention. The present invention is an electrophotographic photoreceptor having a photosensitive layer in which a binder, a charge generating agent and a charge transfer agent are combined in various forms on a conductive support,
An electrophotographic photoreceptor comprising the indole compound represented by Structural Formula 1 in the photosensitive layer.

In the chemical formula ¹ , R ¹ is a hydrogen atom, an optionally substituted alkyl group, an alkenyl group, an aryl group,
It represents an alkoxyl group or a heterocyclic group. R ² is a hydrogen atom, an optionally substituted alkyl group, an alkenyl group,
It represents an aryl group or a heterocyclic group. R ³ represents an alkylene group or an arylene group. R ⁴ and R ⁵ are hydrogen atoms,
It represents an optionally substituted alkyl group or aryl group.

Specific examples of the indole compound represented by Structural Formula 1 according to the present invention include the following compounds, but the invention is not limited thereto.

[0013]

[Chemical 3]

[0014]

[Chemical 4]

[0015]

[Chemical 5]

[0016]

[Chemical 6]

[0017]

[Chemical 7]

[0018]

[Chemical 8]

[0019]

[Chemical 9]

[0020]

[Chemical 10]

[0021]

[Chemical 11]

[0022]

[Chemical 12]

[0023]

[Chemical 13]

[0024]

[Chemical 14]

[0025]

[Chemical 15]

[0026]

[Chemical 16]

[0027]

[Chemical 17]

[0028]

[Chemical 18]

[0029]

[Chemical 19]

[0030]

[Chemical 20]

[0031]

[Chemical 21]

[0032]

[Chemical formula 22]

[0033]

[Chemical formula 23]

[0034]

[Chemical formula 24]

[0035]

[Chemical 25]

[0036]

[Chemical formula 26]

[0037]

[Chemical 27]

[0038]

[Chemical 28]

[0039]

[Chemical 29]

[0040]

[Chemical 30]

[0041]

[Chemical 31]

[0042]

[Chemical 32]

[0043]

[Chemical 33]

[0044]

[Chemical 34]

[0045]

[Chemical 35]

[0046]

[Chemical 36]

[0047]

[Chemical 37]

[0048]

[Chemical 38]

[0049]

[Chemical Formula 39]

[0050]

[Chemical 40]

[0051]

[Chemical 41]

[0052]

[Chemical 42]

In the electrophotographic photoreceptor according to the present invention, wherein the indole compound represented by the structural formula 1 is contained in the photosensitive layer, the charge generating agent contained in the photosensitive layer is metal phthalocyanine. , Phthalocyanine compounds represented by metal-free phthalocyanines, perylene anhydrides, perylene compounds represented by perylene imides, anthraquinone derivatives, anthanthrone derivatives, polycyclic quinone compounds represented by violanthrone derivatives, An azo compound represented by a monoazo compound, a polyazo compound, a pyrazolone azo compound, or the like is used, and among them, the bisazo compound represented by the structural formula 2 is preferable because it exhibits a more excellent effect.

In the chemical formula 2, A is a hydrogen atom, an optionally substituted alkyl group, an aryl group, or a heterocyclic group, m and n are 0 or 1, and B represents a coupler residue.

In the structural formula 2, B represents a residue of a coupler which reacts with a diazo group. The coupler residue of the structure represented by the general formulas b-1 to b-10 shown in Tables 1 and 2 is used. Is particularly effective.

[0056]

[Table 1]

[0057]

[Table 2]

In Tables 1 and 2, Y is condensed with a benzene ring to form a polycyclic aromatic ring such as a naphthalene ring, anthracene ring and phenanthrene ring, or a benzene ring to be condensed with a carbazole ring, a benzocarbazole ring and a dibenzofuran ring. Represents a group of atoms necessary to form a heterocycle such as.

R ⁶ is an optionally substituted alkyl group (eg, methyl group, ethyl group, n-propyl group, i
so-propyl group, n-butyl group, sec-butyl group,
(Amyl group, 1-octyl group, benzyl group, p-chlorobenzyl group, 3,4-dichlorobenzyl group, p-methylbenzyl group, 2-phenylethyl group, α-naphthylmethyl group, β-naphthylmethyl group, etc.) , An aryl group (eg,
Phenyl group, tolyl group, xylyl group, biphenyl group, chlorophenyl group, bromophenyl group, methoxyphenyl group, ethoxyphenyl group, butoxyphenyl group, phenoxyphenyl group, nitrophenyl group, cyanophenyl group, hydroxyphenyl group, carboxyphenyl group ,
N, N-dimethylaminophenyl group, α, α, α-trifluoromethylphenyl group, methylthiophenyl group, α-
Naphthyl group, β-naphthyl group, etc.).

R ⁷ represents R ⁶ and a heterocyclic group (eg, thiazolyl group, 5-nitrothiazolyl group, carbazolyl group, indolyl group, pyrrolyl group, acridyl group, benzo (b) thiophenyl group, benzimidazolyl group, oxazolyl group,
Chlorooxazolyl group, triazolyl group, piperidyl group, pyridyl group, quinolyl group, etc.). R ⁸ represents an oxygen atom, a sulfur atom, —NH—, R ⁹ and R ¹⁰ represent a hydrogen atom, an optionally substituted alkyl group, a nitro group, a methoxy group, an ethoxy group, an acetyl group, a cyano group, a halogen atom. Represents Z is a chain hydrocarbon necessary for forming a 5-membered ring and a 6-membered ring.

Further, specific examples of the bisazo compound represented by the structural formula 2 according to the present invention are shown in Tables 3 and 4,
Examples thereof include those having the structural formulas shown in Table 5, Table 6, Table 7, and Table 8, but are not limited thereto.

[0062]

[Table 3]

[0063]

[Table 4]

[0064]

[Table 5]

[0065]

[Table 6]

[0066]

[Table 7]

[0067]

[Table 8]

A preferable electrophotographic photosensitive member according to the present invention is obtained by incorporating the indole compound represented by the structural formula 1 and the bisazo compound represented by the structural formula 2 into the photosensitive layer. And has excellent performance.

Hereinafter, each component of the present invention will be described in detail.

First, as the conductive support on which the photosensitive layer of the photoconductor is formed, any of those known in electrophotographic photoconductors can be used. Specifically, for example, gold,
Silver, platinum, titanium, aluminum, copper, zinc, iron,
Examples thereof include a drum, a sheet, a belt made of a metal oxide or the like that has been subjected to a conductive treatment, a laminate of these thin films, and a vapor deposition product.

Further, metal powder, metal oxide, carbon black, carbon fiber, copper iodide, charge transfer complex, inorganic salt,
Drums, sheets, belts, etc. made of plastic, ceramics, paper, etc., which are obtained by coating a conductive substance such as an ion-conductive polymer electrolyte with a suitable binder and embedding it in a polymer matrix and subjecting it to a conductive treatment .

The photosensitive layer is composed of a single layer type in which a charge generating agent and a charge transfer agent are dispersed and mixed and enclosed in a binder, and a laminated type in which the charge generating agent and the charge transfer agent are separated and sealed in a binder. . The present invention can be applied to any system, but is preferably used in a system of a function-separated type laminated photoreceptor in which the performance of the charge generating agent and the charge transfer agent can be maximized.

In the function-separated laminated photoreceptor, the charge generation layer is composed of at least the above charge generation agent and the binder resin. As the charge generation layer binder resin used, styrene, vinyl acetate, which has been conventionally known,
Polymers and copolymers of vinyl compounds such as acrylic acid ester and methacrylic acid ester, silicone resin, phenoxy resin, formal resin, butyral resin, urethane resin, phenol resin, polyamide resin, polyimide resin, polycarbonate resin, polyester resin, poly Examples include but are not limited to arylate resins.

The charge generating layer binder resin is used in an amount of 1 to 1000 parts by weight, preferably 1 to 400 parts by weight, based on 100 parts by weight of the charge generating agent. The thickness of the charge generation layer is 0.05 to 20 μm, preferably 0.1 to 2 μm.

As the solvent to be used, ethers such as 1,2-dimethoxyethane, tetrahydrofuran, 1,4-dioxane and 1,3-dioxolane, ketones such as methyl ethyl ketone and cyclohexanone, toluene,
Aromatic hydrocarbons such as xylene, aprotic polar solvents such as N, N-dimethylformamide, acetonitrile, N-methylpyrrolidone and dimethylsulfoxide, alcohols such as methanol, ethanol and 2-propanol,
Examples thereof include esters such as methyl acetate, ethyl acetate and methyl cellosolve acetate, halogenated hydrocarbons such as dichloroethane and chloroform.

The charge transfer layer can be provided by adding a charge transfer agent such as a hydrazone compound or a styryl compound and a binder resin, dissolving it in a suitable solvent, and coating it.

As the binder resin used, styrene, vinyl chloride, vinyl acetate, acrylate ester,
Polymers and copolymers of vinyl compounds such as methacrylic acid esters, polycarbonate resins, polyarylate resins,
Examples thereof include various polymers such as polyester resin, phenoxy resin, polysulfone, cellulose ester resin, cellulose ether resin, urethane resin, epoxy resin and silicone resin.

Examples of the solvent used include tetrahydrofuran, 1,3-dioxolane, methyl ethyl ketone, benzene, toluene, monochlorobenzene, 1,2-dichloroethane, dichloromethane, chloroform and ethyl acetate.

The binder resin for the charge transfer layer is used in an amount of 10 to 500 parts by weight, preferably 50 to 200 parts by weight, based on 100 parts by weight of the charge transfer agent. The thickness of the charge transfer layer is 1 to 100 μm, preferably 10 to 50 μm
Used in the range of m.

Specific examples of the charge transfer agent include the following, but are not limited to these.

[0081]

[Chemical 43]

[0082]

[Chemical 44]

[0083]

[Chemical formula 45]

[0084]

[Chemical formula 46]

[0085]

[Chemical 47]

[0086]

[Chemical 48]

[0087]

[Chemical 49]

[0088]

[Chemical 50]

[0089]

[Chemical 51]

[0090]

[Chemical 52]

[0091]

[Chemical 53]

[0092]

[Chemical 54]

[0093]

[Chemical 55]

[0094]

[Chemical 56]

[0095]

[Chemical 57]

[0096]

[Chemical 58]

[0097]

[Chemical 59]

[0098]

[Chemical 60]

[0099]

[Chemical formula 61]

[0100]

[Chemical formula 62]

[0101]

[Chemical formula 63]

[0102]

[Chemical 64]

[0103]

[Chemical 65]

A blocking layer may be provided between the photosensitive layer and the conductive support in order to control charge injection from the photosensitive layer to the conductive support. A surface protective layer may be provided in order to improve.

Further, the photosensitive layer may contain a well-known plasticizer in order to improve film formability, flexibility and mechanical strength. Examples of the plasticizer include phthalic acid esters, phosphoric acid esters, chlorinated paraffins, chlorinated fatty acid esters, aromatic compounds such as methylnaphthalene, and the like.

Furthermore, in order to improve the electrophotographic characteristics of the photoconductor, an additive such as an antioxidant may be contained.

[0107]

EXAMPLES The present invention will now be described in more detail by way of examples, which should not be construed as limiting the invention thereto.

Example 1 1 part by weight of the charge generating agent represented by Exemplified Compound P-1, 1 part by weight of polyvinyl butyral resin (Denka Butyral # 3000-K manufactured by Denki Kagaku KK) and Indole represented by Exemplified Compound 3 0.03 parts by weight of the compound was mixed with 100 parts by weight of 1,2-dimethoxyethane, and dispersed with glass beads for 4 hours by a paint conditioner. The pigment dispersion thus obtained was coated on an aluminum vapor deposition film (Metal Me manufactured by Toray Industries, Inc.) with an applicator, and the temperature was 80 ° C.
And dried for 15 minutes to obtain a charge generation layer having a thickness of about 0.2 μm.

Next, 10 parts by weight of the charge transfer agent represented by the chemical formula 44, 10 parts by weight of a polycarbonate resin (Panlite C-1400 manufactured by Teijin Chemicals Ltd.) and 0.1 part by weight of DL-α-tocopherol are added to dichloromethane. The solution was dissolved in 150 parts by weight, and the solution was applied onto the charge generation layer with an applicator and dried at 80 ° C. for 60 minutes to form a charge transfer layer having a dry film thickness of 20 μm.

The laminated electrophotographic photosensitive member thus produced was allowed to stand for a whole day and night in a dark place of a low temperature and low humidity environment (5 ° C., 30%), and then an electrostatic recording test apparatus was used in the low temperature and low humidity environment. (Kawaguchi Denki Co., Ltd. SP-428) was used to evaluate the electrophotographic characteristics. The measurement conditions are: corona applied voltage: -5 kV,
Static mode No. 3 (Process speed 167 mm
/ Sec), illumination light (white light) illuminance: 2lux. As a result, the charging potential was −710 V and the half exposure was 1.3 lux.
・ It showed a very high sensitivity value of seconds.

Next, this photoconductor was attached to an aluminum drum base tube, and the repeating characteristics of charging and photo-erasing were evaluated by a drum photoconductor evaluation device (Cynthia 90 manufactured by Gentec Co., Ltd.). Measurement is performed in a low temperature and low humidity environment, corona applied voltage: -5.2 kV, process speed 160 mm /
For 5 seconds, the charging and photo-erasing were repeated 5000 times in the TCCD2 mode. Photostatic elimination was performed using a tungsten lamp array. Table 9 shows the measurement results of the surface potential after charging, that is, the charging potential, and the surface potential after removing the light, that is, the residual potential. It can be seen that the changes in charging potential and residual potential are extremely small.

[0112]

[Table 9]

Examples 2 to 10 The charge generating agent represented by Exemplified compound P-1 and the charge transfer agent represented by Chemical compound 44 and the indole compound represented by Chemical compound 3 are exemplified compounds shown in Table 10. A laminated photoconductor was prepared in the same manner as in Example 1 except that the half exposure amount of the photoconductor was measured under the same measurement conditions as in Example 1.
And the repeated characteristics were measured. The results are shown in Table 11.

[0114]

[Table 10]

[0115]

[Table 11]

Comparative Examples 1 to 10 Photoreceptors were prepared in the same manner as in Example 1 except that the indole compound was not contained in the charge generation layer in Examples 1 to 10, and the photoreceptors were measured under the same measurement conditions as in Example 1. The half-exposure amount and the repeating characteristics of the above were measured. The combinations of the charge generating agent and the charge transfer agent used are shown in Table 12, and the measurement results are shown in Table 13.

[0117]

[Table 12]

[0118]

[Table 13]

Examples 11 to 15 Laminated photoreceptors were prepared in the same manner as in Example 1 except that the charge generating agent, charge transfer agent and indole compound shown in Table 14 were used, and exposed under the same measurement conditions as in Example 1. The half-exposure amount of the body and the repeating characteristics were measured. The results are shown in Table 15.

[0120]

[Table 14]

[0121]

[Table 15]

Comparative Examples 11 to 16 Photosensitive members were prepared in the same manner as in Example 1 except that the indole compound was not contained in the charge generation layer in Examples 11 to 16, and the photosensitive members were measured under the same measurement conditions as in Example 1. The half-exposure amount and the repeating characteristics of the above were measured. The combinations of the charge generating agent and the charge transfer agent used are shown in Table 16, and the measurement results are shown in Table 17.

[0123]

[Table 16]

[0124]

[Table 17]

Example 17 1 part by weight of a charge generating agent represented by Exemplified Compound P-12 and phenoxy resin (PKHJ manufactured by Union Carbide Co., Ltd.) 1
And 100 parts by weight of 1,2-dimethoxyethane were mixed with 1 part by weight and dispersed with glass beads for 4 hours by a paint conditioner. The pigment dispersion thus obtained was coated on an aluminum vapor-deposited film (Metal Me manufactured by Toray Industries, Inc.) with an applicator and dried at 80 ° C. for 15 minutes to obtain a charge generation layer having a thickness of about 0.2 μm.

Next, 10 parts by weight of the charge transfer agent represented by the exemplified compound formula 47, 0.1 part by weight of the indole compound represented by the exemplified compound formula 8 and the polycarbonate resin (Teijin Kasei) are used.
7 parts by weight of Panlite TS-2020 manufactured by Co., Ltd. and 3 parts by weight of polyester resin (Vylon 290 manufactured by Toyobo Co., Ltd.) and D
0.1 parts by weight of L-α-tocopherol was dissolved in 150 parts by weight of dichloromethane, and this solution was applied onto the above charge generation layer by an applicator and dried at 80 ° C. for 60 minutes to obtain a dry film thickness of 20 μm. A transfer layer was formed.

The half-exposure amount of the photoconductor and the repetitive characteristic of the photoconductor prepared as described above were measured under the same measurement conditions as in Example 1. The results are shown in Table 18.

[0128]

[Table 18]

Examples 18 to 26 Exemplified Compounds P-12 as charge generators and Exemplified Compounds 47 as charge transfer agents and Exemplified Compounds Exemplified compounds shown in Table 19 instead of indole compounds as shown in Chemical Formula 8 A laminated photoconductor was prepared in the same manner as in Example 17 except that was used, and the half-exposure amount of the photoconductor and the repeating characteristics were measured under the same measurement conditions as in Example 1. The results are shown in Table 20.

[0130]

[Table 19]

[0131]

[Table 20]

Comparative Examples 17-26 Photoreceptors were prepared in the same manner as in Example 17 except that the charge transfer layer was not used in Examples 17-26. The half-exposure amount and the repeating characteristics of the above were measured. The combinations of the charge generating agent and the charge transfer agent used are shown in Table 21, and the measurement results are shown in Table 22.

[0133]

[Table 21]

[0134]

[Table 22]

Examples 27 to 32 Laminated photoreceptors were prepared in the same manner as in Example 1 except that the charge generating agent, charge transfer agent and indole compound shown in Table 23 were used, and exposed under the same measurement conditions as in Example 1. The half-exposure amount of the body and the repeating characteristics were measured. The results are shown in Table 24.

[0136]

[Table 23]

[0137]

[Table 24]

Comparative Examples 27 to 32 Photoreceptors were prepared in the same manner as in Example 1 except that the indole compound was not contained in the charge generation layer in Examples 27 to 32, and the photoreceptors were measured under the same measurement conditions as in Example 1. The half-exposure amount and the repeating characteristics of the above were measured. The combinations of the charge generating agent and the charge transfer agent used are shown in Table 25, and the measurement results are shown in Table 26.

[0139]

[Table 25]

[0140]

[Table 26]

From these results, the photoconductors of the present invention shown in Examples are excellent in electrophotographic characteristics, especially in stability of charging potential and residual potential due to repeated use, in low temperature and low humidity environment as compared with Comparative Examples. You can see that

[0142]

As is apparent from the above, according to the present invention, it is possible to provide an electrophotographic photoreceptor having high sensitivity and excellent repetitive characteristics in a low temperature and low humidity environment.

Claims (6)

[Claims] 1. An electrophotographic photosensitive member comprising a conductive support and a photosensitive layer containing at least a charge generating agent and a charge transfer agent, wherein the photosensitive layer contains an indole compound represented by the following structural formula 1. An electrophotographic photoconductor characterized by: [Chemical 1] (In Chemical Formula 1, R ¹ represents a hydrogen atom, an optionally substituted alkyl group, an alkenyl group, an aryl group, an alkoxyl group, or a heterocyclic group. R ² represents a hydrogen atom, an optionally substituted alkyl group. , An alkenyl group, an aryl group,
Or represents a heterocyclic group. R ³ represents an alkylene group or an arylene group. R ⁴ and R ⁵ represent a hydrogen atom, an optionally substituted alkyl group, or an aryl group. ) 2. The electrophotographic photosensitive member according to claim 1, wherein the charge generating agent is a bisazo compound represented by the following structural formula 2. [Chemical 2] (In Chemical formula 2, A is a hydrogen atom, an optionally substituted alkyl group, an aryl group, or a heterocyclic group, m and n are 0 or 1, and B represents a coupler residue.) 3. The photosensitive layer according to claim 1 or 2, wherein the photosensitive layer has at least a charge generation layer and a charge transfer layer, and the charge generation layer contains the indole compound represented by the structural formula 1. An electrophotographic photoreceptor characterized by: 4. The electrophotographic photosensitive member according to claim 3, wherein the content of the indole compound represented by Chemical formula 1 is in the range of 1 to 20 parts by weight with respect to 100 parts by weight of the charge generating agent. . 5. The photosensitive layer according to claim 1 or 2, wherein the photosensitive layer has at least a charge generation layer and a charge transfer layer, and the charge transfer layer contains an indole compound represented by the structural formula 1. An electrophotographic photoreceptor characterized by: 6. The electrophotography according to claim 5, wherein the content of the indole compound represented by Chemical formula 1 is in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the charge transfer agent. Photoconductor.