JPS6132063A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance sensitivity, repetititon use characteristics, etc., by using a sepecified azo pigment stable against heat and light and superior in carrier generating ability as a photoconductor for constituting a photosensitive layer. CONSTITUTION:The intended electrophotographic sensitive body is obtained by incorporating in the photosensitive layer an azo pigment represented by formula I, in which R1, R2, R3 being H, halogen, 1-4C alkyl, alkoxy, and Cp being a coupler residue, and this azo pigment is synthesized by tetraazotizing diamine represented by formula II, such as 2',6-diamino-2-phenylbenzotriazole, and coupling the product with the corresponding coupler, such as formula III or IV, in the presence of alkali. The azo pigment of formula I exhibits especially superior effect when it is used as the carrier generating substance of the photosentive layer contg. the carrier tranfer substance and the carrier generating substance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor, and more particularly to a novel electrophotographic photoreceptor having a photosensitive layer containing an azo pigment.

Fourth, in detail, the present invention relates to a highly durable electrophotographic photoreceptor which has high sensitivity and is suitable for repeated use.

Conventionally, electrophotographic photoreceptors having a photosensitive layer entirely composed of inorganic photoconductors such as selenium, zinc oxide, and hdium sulfide have been widely known.

However, these are not necessarily satisfactory in terms of sensitivity, thermal stability, moisture resistance, durability, etc. In addition, selenium and cadmium sulfide are particularly toxic, so they are difficult to manufacture.
There were also restrictions on handling.

On the other hand, electrophotographic photoreceptors having a photosensitive layer mainly composed of an organic photoconductive compound are relatively easy to manufacture, inexpensive, and easy to handle. It has many advantages, including excellent thermal stability, and has attracted a lot of attention in recent years.

Poly-N-vinylcarbazole is well known as such an organic photoconductive compound, and 2.4.
Electrophotographic photoreceptors having a photosensitive layer containing as a main component a charge transfer complex formed from a Lewis acid such as 7-dolinitro and 9-fluorenone are not necessarily satisfactory in terms of sensitivity and durability.

On the other hand, layered or dispersed function-separated photoreceptors, in which the carrier generation function and the carrier transport function are assigned to separate substances, have a wide range of materials to choose from, and their charging characteristics, sensitivity, and durability It has the advantage that an electrophotographic photoreceptor having arbitrary properties can be produced relatively easily in terms of electrophotographic properties such as properties.

Conventionally, various carrier-generating substances or carrier-transferring substances have been proposed.

For example, a carrier generation layer made of amorphous selenium and a
An electrophotographic photoreceptor having a photosensitive layer in combination with a carrier transport layer containing 1-N-vinylcarbazole as a main component has been put into practical use.

However, a carrier generation layer made of amorphous selenium has a drawback of poor durability.

In addition, various proposals have been made to use organic dyes and pigments as carrier-generating substances.
Japanese Patent Publication No. 48-30513, Japanese Patent Publication No. 52-4241
Publication No. 1983-46558, Japanese Patent Publication No. 1987-46558
11945 and the like are already known.

However, these azo pigments have poor characteristics such as sensitivity, residual potential, and stability after repeated use.
The reality is that nothing that fully satisfies the wide range of requirements of electrophotographic processes has not been obtained, and the selection range of carrier transfer substances is also limited.

An object of the present invention is to provide an electrophotographic photoreceptor containing an azo compound that is stable to heat and light and has excellent carrier generation ability.

Another object of the present invention is to provide high sensitivity, low residual potential,
Another object of the present invention is to provide an electrophotographic photoreceptor with excellent durability whose properties do not change even after repeated use.

Still another object of the present invention is to provide an electrophotographic photoreceptor containing an azo compound that can effectively act as a carrier generating substance even in combination with a wide variety of carrier transfer substances.

As a result of intensive research to achieve all of the above objectives, the inventor has
The present invention was completed based on the discovery that an azo pigment represented by the following general formula can function as an active ingredient of a photoreceptor.

That is, the present invention provides the following general formula (1) on a conductive support.
This is an electrophotographic photoreceptor characterized by having a photosensitive layer containing an azo pigment represented by:

(In the formula, R1, R2 and R3 are hydrogen, or)) a rogen atom or an alkyl or alkoxy having 1 to 4 carbon atoms, &f, and Cp represents all coupler residues. That is, in the present invention, the azo pigment represented by the above general formula is used as a photoconductive substance constituting the photosensitive layer of an electrophotographic photoreceptor. Using Koze 1 as a carrier generating material for a so-called function-separated type electrophotographic photoreceptor in which carrier generation and transfer are performed by separate substances (this has excellent film properties, charge retention ability, and sensitivity). , an electrophotographic product with excellent electrophotographic properties of residual potential holding, and less fatigue deterioration even after repeated use, and the above-mentioned properties do not change even when exposed to heat or light, and can exhibit stable properties. Photoreceptors can be created.

Regarding the method for synthesizing the azo pigment represented by the above general formula, its characteristics are the same as those of the following formula (u) (wherein R1, R2, and R3 are formula 11). ) is tetrazotized by a conventional method, and then the corresponding coupler is cupped in the presence of an alkali, or the tetrazonium salt of the diamine is converted into -l in the form of a borofluoride salt or salivary lead chloride double salt. After primary isolation, it can be easily synthesized by coupling with a coupler in a suitable solvent such as N,N-dimethylformamide, dimethylsulfoxide, etc. in the presence of an alkali.

Specific examples of diamines include the following compounds.

2 6-diamino-2-phenylbenztriazole,
3',6-Diami2-2-phenylbenztriazole, 4',6-Diami2-2-phenylbenztriazole, 2',6-Diami24'-chloro-2-phenylbenztriazole, 4',6-Diami2'-
Chloro-2-phenylbenztriazole, 416-Diami2-3'-chloro-2-phenylbenztriazole, 4',6-Diami2-5-chloro-2-phenylbenztriazole, 3?6-Diami2-5-chloro-2
-Phenylbenztriazole, 4'6-diamitu3
', 5-dichloro-3-phenylbentriazole,
2',6-Diami2-4'-methyl-2-phenylbenztriazole, 3',6-Diami2-4-methyl-
2-phenylbenztriazole, 4',6-diamitu-3'-methyl-2-phenylbenztriazole,
3',6-Diami2-5-methyl-2-phenylbenztriazole, 3',6-Diami2-7-methyl-2-
Phenylbenztriazole, 3',6-diamitu4
', 5-dimethyl-2-7enylbenztriazole,
3',6-Diami2,5-dimethyl-2-phenylbenzj.Riazole, 3',6-Diami22'7-
dimethyl-2-phenylbenztriazole, 4',
6-Diamitwo 2', 5'-dimethyl-2-phenylbenztriazole, 4', 6-Diamitwo 2', 5',
5-trimethyl-2-7enylbenztriazole, 2
',6-Diami2-4'-methoxy-2-phenylbenztriazole,3',6-Diami2-5-methoxy-
2-phenylbenztriazole, 4',6-diamitu-3'-methoxy-2-phenylbenztriazole,
4′.

6-Diami2-5-methoxy-2-phenylbenztriazole, 3',6-diami2-5,6'-dimethoxy-2-phenylbenztriazole, 4',6-cyami22'+ 5+ s'l'rimethoxy-2- Phenylbenztriazole, 3',6-diamitu6'-
Methoxy-2-phenylbenztriazole, 3',6
-Diami24'-methyl-5-chloro-2-phenylbenztriazole, 3',6-Diami26'-Meshi-ζ -hm Lo -9--F--ki11
, ψ 17 → S L II Mall 4', 6-
Diamitwo 6'-methyl-5-chloro-2-7enylbenzt+1 Azole, 4',6-diami, 1-5-methyl-3'-chloro-2-phenylbenz I Riazole, 4',6-diamitwo 7 -methyl-5'-chloro-2
-Phenylbenztriazole, 3',6-diamitou6'-methoxy-5-chloro-2-phenylbenztriazole, 4',6-diamitouJ'-1t-+C5
-Chloro-2-phenylbenztriazole, 4',6
-Diami2-5-methoxy-3'-chloro-2-phenylbenztriazole, 3',6-diamitou6'-methyl-5-methoxy-2-phenylbenztriazole, 3',6-diamitou5-methyl-6' -Methoxy-
2-Phenylbenztriazole, 3',6-diamino-4'-methyl-5-7toxy2-phenylbenztriazole, 4',b-diamino-2'-methyl-5'
-methoxy-2-phenylbenztriazole, 4',
6-diami2-3'-)'r-5-))xy-
2-phenylbenztriazole, 4',6-diamitou-2'-methyl-5-methoxy-2-phenylbenztriazole-4',6-diamitou-7-methyl-3'-
Methoxy-2-phenylbenztriazole, 4',6
-cyamitsu 2',5'-dimethyl-5-methoxy-
2-phenylbenztriazole, 4'6-diamitou-5-methyl-2', 5'-dimethoxy-2-phenylbenztriazole, 4',6-diamitou-7-methyl-2', 5'-dimethoxy-2-phenylbenz l-Q
Azole and 4',6-diamitu-2'-methyl-5,
5'-dimethoxy-2-phenylbenztriazole.

The diamines mentioned above are synthesized by known methods and are often known.

Next, Cp represents a coupler residue, and a specific example is the coupler residue of formula (1).

'X' (wherein, - indicates an atomic group necessary for forming an alkyl group that may be substituted (e.g., methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, 1Iec-butyl group, amyl group) , 1-
Octyl group, benzyl group, rollbenzyl group, dichlorobenzyl group, methylbenzyl group, 2-phenylethyl group, α-naphthylmethyl group, β-naphthylmethyl group) Aryl group (e.g. phenyl group, tolyl group, xylyl group) ,
Biphenyl group, chlorophenyl group, dichlorophenyl group, bromphenyl group, methoxyphenyl group, dioxyphenyl group, butoxyphenyl group, phenoxyphenyl group, nitrophenyl group, cyanophenyl group, hydroxyphenyl group, carboxyphenyl group, N, N -dimethylaminophenyl group, acetylphenyl group, benzoylphenyl group, ethylphenyl group, α, α, α-trifluoromethylphenyl group, methylthiophenyl group, α-naphthyl group, β-naphthyl group, etc.), heterocyclic group ( For example, thiazolyl group, 5-nitrothiazolylcarbazolyl group, ethylcarbazolyl group, benzothiazolyl group, piperidyl group, pyridyl group, morpholyl group, benzoxasilyl group, furyl group, oxasilyl group, triazolyl group, quinolinyl group) shows. R5 represents 0, S, or NH. R6 represents hydrogen, an optionally substituted alkyl group, a nitro group, a methoxy group, an ethoxy group, an acetyl group, or a halogen.

The electrophotographic photoreceptor of the present invention is known to have a photosensitive layer in various forms containing one or more azo pigments represented by the general formula (1). The photosensitive layer of the photoreceptor for use is usually of the type shown below.

■ A photosensitive layer made of an azo pigment ■ A photosensitive layer containing an azo pigment dispersed in a binder ■ A photosensitive layer containing an azo pigment dispersed in a well-known charge transfer substance A photosensitive layer formed by laminating a charge transfer layer contained in a well-known charge transfer material.The azo pigment represented by the above general formula generates charge carriers with extremely high efficiency when it absorbs light. Although the generated carrier can be transferred using an azo pigment as a medium, it is preferable to transfer the generated carrier using a well-known charge transfer material as a medium. From this point of view, photosensitive layers having the forms (1) and (2) are particularly preferred.

Charge transfer substances are generally dispersed into two types: electron transfer substances and hole transfer substances, but both can be used in the photosensitive layer of the photoreceptor of the present invention, and although they have the same type of function, Mixtures or mixtures of different functionalities can also be used. As substances that have electron transfer, 21.
It is an electron-withdrawing compound having an electron-withdrawing group such as a cyano group, an ester group, etc.
, 4.7-Dolinitrofluorenone, 2.4.5.7-
Titranitrofluorenone or tetracyanoquinodimethane, tetracyanoethylene, 2,4.5.7-titranitroxanthone 2,4
．． 8-Compounds such as I + nidrothioxanthone,
Examples include polymerized electron-absorbing compounds.

Further, as a hole transfer medium, examples of electron-donating organic photoconductive compounds include the following.

hydrazones 2H5 2H3 C2M.

<Pyrazolines> (6) CzHa Diarylalkane 9A> nC5H7 n-C3H.

(,U) -C3H7 n-C31(7 -C3H7 2H5 n C387 Hz nC6T(tx (]0) 2 H6 (Jl) <Alkylene diamines><Dibenzylanilines> (3) CHa <Triphenylamines><Diphenylbenzylamines><Triarylalkane> H3, (4) CH3 <Oxadiazole> N-N <Anthracene><Oxazole> II -N-vinylcarbazole, halogenated carbon 1l
-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, polyglycidylcarbazole, polyvinylacenaphthylene, ethyl rubazole-formaltehyde resin, etc. can also be used.

The electrophotographic photoreceptor of the present invention can be manufactured according to a conventional method.

Inno 11e, an electrophotographic photoreceptor having a photosensitive layer of the type (2) above is prepared by coating a conductive support with a coating solution obtained by dissolving or dispersing the azo pigment of the present invention in a suitable medium. It can be manufactured by drying and forming a photosensitive layer having a thickness of usually several μm to several tens of μm.

As a medium for preparing the coating liquid, basic solvents that dissolve bisazo pigments such as n-butylamine and ethylenediamine, ethers such as tetrahydrofuran and 1,4-dioxane, and ketones such as dimethyl ethyl ketone and cyclohexanone: + - Aromatic hydrocarbons such as xylene: N, N-dimethylformamide acetonitrile, N-
Aprotic polar solvents such as methylpyrrolidone and dimethyl sulfoxide; Alcohols such as methanol, ethanol and isopropanol; Esters such as acetic acid, vinegar f#W methyl and methyl cellosolve acetate; Chlorination of dichloroethane and chloroform, etc. Examples include a medium such as a hydrocarbon that completely disperses the azo pigment.

When using a medium that completely disperses the azo pigment, the total particle diameter of the azo pigment is 5 μm or less, preferably 3/Lm or less, optimally 1
It is necessary to make the particles smaller than μm.

Furthermore, as the conductive support on which the photosensitive layer is formed, any of those employed in well-known electrophotographic photoreceptors can be used.

Specifically, for example, aluminum, @ etc.
, sheets, laminates and vapor deposits of these metal foils.

History of gold 1, bean powder, carbon black, copper iodide, fine molecules? A plastic film coated with a conductive substance such as Ij solution'Ci with a suitable binder and treated without conducting.
Examples include plastic drums, paper, etc., and conductive materials such as metal powder, carbon black, carbon fiber, etc.
Examples include plus thousand sheets and drums that contain 1 and have conductivity.

If a binder is dissolved in the coating liquid used to form the photosensitive layer of the type (2) above, an electrophotographic photoreceptor having the photosensitive layer of the type (2) above can be produced.

In this case, the medium of the coating liquid is preferably one that dissolves the binder.

As binders, polymers of vinyl compounds such as styrene, vinyl acetate, acrylic esters, methacrylic esters, and co-monomers: phenoxy resins, polysulfones, arylate resins, polycarbonates, polyesters,
Examples include cellulose ester lulose ether acrylic polyol resin cylinders.

Usage information of binder: Normally - 0, 1 for azo pigment
It is in the range of ~5 times the weight.

In addition, in forming this type of photosensitive layer,
Disazo pigment in a binder (fine, e.g. particle size 3)
It is preferable that the particles exist in the form of fine particles of 1 μm or less, particularly 1 μm or less.

Similarly, if a charge transfer medium is dissolved in the coating liquid used to form the photosensitive layer of the type (1) above, an electrophotographic photoreceptor having the photosensitive layer of the type (2) above can be manufactured. .

As a charge transfer medium, what are the examples given above? Either can be used.

Apart from charge transfer media such as polyvinylcarbazole and polyglycidylcarbazole which can themselves be used as binders, it is preferable to use all other binders.

As the binder, any of the binders listed above can be used.

In this case, the amount of the binder used is usually 5 to 1101 t times the market weight of the azo pigment, and the amount of the charge transfer medium used is usually 02 to 15 times the market weight of the binder, preferably 03 to 1. The range is 2 times as large.

In the case of a charge transport medium which itself can be used as a binder, it is usually from 5 to 1 for the azo pigment.

twice the amount of IR is used.

In this type of photosensitive layer, it is also preferable that the Yoregis azo pigment is present in the charge transfer medium and the binder in the form of fine particles between the photosensitive layers of the type (1) above.

If a coating solution obtained by dissolving a charge transfer medium in a suitable medium is applied onto the photosensitive layer of the types (1) to (2) above and dried to form a charge transfer layer, the photosensitive layer of the type (2) above can be formed. It is possible to produce an electrophotographic photoreceptor having the following.

In this case, the above-mentioned photosensitive layers (S to ①) play the role of a charge generation layer.

The charge transfer dj 13 times does not necessarily have to be provided on the top of the charge generation layer, but may be provided between the heavy generation layer and the conductive support.

However, the former is preferable in terms of durability.

The formation of the charge attracting layer is carried out in the same manner as the formation of the photosensitive layer in (2) above.

That is, the azo pigment was removed from the coating solution for forming the entire photosensitive layer described in (1) above, and the coating solution was used as Coating 1 (Q).

Typically the charge generating layer is 5 to 50 micrometers thick.

Of course, the photosensitive layer of the electrophotographic photoreceptor of the present invention may contain a known sensitizer.

Suitable sensitizers include Lewis b, which forms a charge transfer tank with organic photoconductive substances, and dyes.

Examples of Lewis acids include (i-chloronyl, 2,3-dichloro-1,4-nasotosonone, 2-methylanthraquinone, 1-ditroanthraquinone, l-chloro-5-dichloro
- Aldehydes of quinones such as laquinone, 2-chloroanthraquinone, phenanthrenequinone, 4-nitrobenzyldehyde, 1,9-benzoylanthracene, indandione, 3,5-dinitrobenzophenone, 3.3' , 5.5'-tetranitrobenzophenone phthalic acid, acid anhydrides such as 4-chloronaphthalic anhydride,
Tetracyanoethyln, terephthalmalonitrile,
Cyano compounds such as 4-nitrobenzalmalonenitrile 3
Electron-withdrawing compounds such as -benzalphthalide, 3-(α-cyano-p-nitrobenzal)phthalide and 3-(a-cyano-p-nitrobenzal)phthalide can be mentioned.

Examples of dyes include I-liphenylmethane dyes such as methyl violet, brilliant green, and crystal violet; thiazine dyes such as methylene blue; quinone dyes such as quinizarin; +1um salt etc. are mentioned.

In addition, there are other inorganic light guides such as selenium and selenium-arsenic alloys.
11 may contain organic photoconductive pigments such as sexual characteristic particles, copper phthalocyanine pigments, and perylene pigments.

Further, the photosensitive layer of the electrophotographic photoreceptor of the present invention may contain a well-known plasticizer in order to improve film formability, flexibility, and mechanical bending If.

As plasticizers, phthalate esters, phosphate esters,
Examples include aromatic compounds such as epoxy compounds, chlorinated paraffins, chlorinated fatty acid esters, and methylnaphthalene.

Moreover, it goes without saying that an adhesive layer, an intermediate layer, and a transparent insulating layer may be included as necessary.

The photoreceptor using the azo pigment of the present invention has madder sensitivity and good color sensitivity, and when used repeatedly, there is little variation in sensitivity and chargeability, and there is little light fatigue, and it has extremely high durability. be.

Fourth, the photoreceptor of the present invention can be used not only in electrophotographic copying machines, but also in lasers, cathode ray tubes (CRT), and light emitting diodes (LEDs).
It can also be widely used in electrophotographic applications, such as photoreceptors in printers that use the light source as a secondary light source.

Next, the present invention will be explained in more detail with reference to all the embodiments.
The present invention is not limited to one or less embodiments that do not go beyond the gist of the invention.

Example 1 Poly-[Stel film laminated with aluminum foil (Alpera l-85 manufactured by Daido Kako Co., Ltd., aluminum film thickness 1
An intermediate layer with a thickness of 005 μm made of vinyl chloride:vinyl acetate:maleic anhydride copolymer (S-LEC MF-10 manufactured by Tsukisui Kagaku Co., Ltd.) was formed on a conductive support consisting of 0μ) as shown in the following table. Add 2z of each pongee material and 2g of polyarylate resin (TR-100 manufactured by Unitika) to 100ml of 1,2-dichloroethane and disperse in a paint conditioner for about 1 hour to obtain an azo compound dispersion,
φ on the intermediate layer so that the film thickness after drying is 0.5μ
A carrier generation layer is formed by drying the cloth, and a carrier transfer substance N,N-dibenzylaminobenzaldehyde is added.
1,1-Siffer hydrazone 51 to Boria Relay 1.
Together with Resin 7z, a solution dissolved in 50 m/1,2-dichloroethane was coated and dried so that the film thickness after drying was 12 μm to form a carrier transport layer, and an electrophotographic photoreceptor of the present invention was prepared. After storing the present photoreceptor at room temperature 30°C in a dark place for - week, the present electrophotographic photoreceptor was tested using an electrostatic paper tester [SP
...4281 (newly manufactured by Kawaguchi Electric) was installed and the following characteristic tests were conducted.

That is, a voltage of -6 KV is applied to the charger to charge the photosensitive layer by corona discharge for 5 seconds, and the potential Vo (V) at that time is
%, then the exposure amount F required to attenuate the surface potential of the photosensitive layer 'kl/:I by irradiating light from a halogen lamp with the illuminance at the photosensitive layer surface being 301 ux.
``z (lux seconds) was calculated.

The charging characteristics of these electrophotographic photoreceptors are shown in the following table.

Pigment used (bisazo pigment represented by general formula (I)) band
Electrical Properties Examples 21 to 40 On the outer surface of a drum made of aluminum with a diameter of 60wn and made of vinyl chloride:vinyl acetate (87:13) copolymer (VYHH manufactured by UCIC), a thickness of 004μ was coated.
to form an intermediate layer of 4fi'? of each pigment shown in the following table. !
A dispersion obtained by dispersing 4001 nl of l-1,2-dichloroethane and a paint conditioner for about 3 hours was applied onto the intermediate layer so that the film thickness after drying was 0.2 μm.
The entire carrier generation layer was formed by coating and drying to obtain the following. On this carrier generation layer (here, a carrier transfer substance N represented by the structural formula, N-diallylaminobenzaldehyde, -1-phenyl-1-methylhydrazone 10) was coated with a polycarbonate resin (Panrye 1 manufactured in large quantities).
-L-1250) A solution of 12F and 1,2-dichloroethane ioom/ is applied and dried to a film thickness of 15 μm after drying to form a carrier moving layer, and the drum-type electrophotography according to the present invention A photoreceptor was produced. After that, an electrophotographic property test was conducted in the same manner as in Example 1. The results are shown in the table below.

Charging characteristics Example 11 A spectrophotometer (Shimadzu VUV-
365), and the graph is shown in FIG. From this graph, it was found that the maximum absorption wavelength of the present photoreceptor in the visible region was around 600 nm to 720 nm. Furthermore, when the spectral sensitivity at 630 nm and 670 nm was measured using a monochrome meter, the energy required to reduce the potential by half was 4.5 nm for both wavelengths. Oerg/crL is a very high photoreceptor, and a light emitting diode (LRD) is used as a light source.
) and a gas laser, the photoreceptor was found to be sufficiently durable for practical use.

Examples 42-50 Styrene:ethyl methacrylate:methacrylic acid ternary copolymer (styrene 70
) 11%, acid value 310), diethylaminobenzaldehyde-N,N-diphenylhydronozone, and the azo pigment t-1 shown in the following table at a commercial ratio of 07:015, and this was dissolved in dioxane (resin component , a hydrazone compound) dispersion (azo pigment) was applied and dried to prepare a single-layer photoluminescent material with a film thickness of 6 μm.

The photoreceptor of the present invention thus prepared was subjected to an electrophotographic property test using the electrostatic paper tester described above.

The applied voltage was +6KV.

The original plate could be easily created.

When offset printing was performed using this original plate, it was found that it could withstand printing of about 100,000 sheets.

In addition, in order to obtain a toner visible image (light source: halogen lamp)
The optimal exposure was 50 lux for 2 seconds. In addition, when creating the original printing plate, direct plate making was performed without using any base material.

[Brief explanation of drawings]

FIG. 1 is a reflection spectrum of the photoreceptor of Example 24 of the present invention. (Reference plate; aluminum plate) Fig. 1 400 500 600 700
80OL -k (su)

Claims (4)

[Claims] (1) An electrophotographic photoreceptor comprising a photosensitive layer containing an azo pigment represented by the following general formula (I) on a conductive support. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) (In the formula, R_1, R_2, and R_3 represent hydrogen, a halogen atom, or an alkyl or alkoxy group having 1 to 4 carbon atoms, and Cp represents a coupler residue. .) (2) The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer contains a carrier-transferring substance and a carrier-generating substance, and the carrier-generating substance is an azo pigment represented by the general formula. (3) The electrophotographic photoreceptor according to claim 1, wherein the azo pigment represented by the general formula (I) is a compound represented by the following structural formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (Cp is a coupler residue.) (4) The electrophotographic photoreceptor according to claim 1, wherein the azo pigment represented by the general formula (I) is a compound represented by the following structural formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (Cp is a coupler residue.)