JP3143525B2 - Electrophotographic photoreceptor, electrophotographic apparatus provided with the electrophotographic photoreceptor, and facsimile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic apparatus and a facsimile equipped with the electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor having a photosensitive layer containing an azo pigment having a specific structure. And an electrophotographic apparatus and a facsimile provided with the electrophotographic photosensitive member.

[0002]

2. Description of the Related Art Conventionally, an electrophotographic photoreceptor using an inorganic photoconductor such as selenium, cadmium sulfide, or zinc oxide as a photosensitive component has been known. On the other hand, a number of organic photoconductors have been developed since the discovery that specific organic compounds exhibit photoconductivity. For example, organic photoconductive polymers such as poly-N-vinyl carbazole and polyvinyl anthracene, carbazole, anthracene, pyrazolines,
Low molecular organic photoconductors such as oxadiazols, hydrazones, arylalkanes, and phthalocyanine pigments;
Organic pigments and dyes such as azo pigments, cyanine pigments, polycyclic quinone pigments, perylene pigments, indigo dyes, thioindigo dyes, and squaric acid methine dyes are known. In particular, organic pigments and dyes having photoconductivity are easier to synthesize than inorganic materials, and the variety in which compounds exhibiting photoconductivity in an appropriate wavelength range can be selected has been expanded. Photoconductive organic pigments and dyes have been proposed. For example, U.S. Pat. Nos. 4,123,270, 4,247,614 and 4,251,613.
No. 4,251,614, No. 4,256
No. 821, No. 4260672, No. 4
No. 268596, No. 4278747,
An electrophotographic photoreceptor using an azo pigment exhibiting photoconductivity as a charge generating material in a photosensitive layer functionally separated into a charge generating layer and a charge transporting layer, as disclosed in the specification of JP-A-4293628, is known. I have. Also, U.S. Pat.
No. 7,9981, No. 4,352,876, No. 4,356,243, No. 4,390,611, No. 4,418,133, No. 4,436,800
No. 4,439,506, No. 4447
No. 513, No. 4471040, No. 4
No. 495264, No. 4551404,
No. 4571369, No. 4582771, No. 4599287, No. 460067
Azo pigments disclosed in, for example, JP-A No. 4 (1999) are also known as charge generating substances in the photosensitive layer.

An electrophotographic photoreceptor using such an organic photoconductor can be produced by coating by appropriately selecting a binder, so that an extremely high productivity and inexpensive photoreceptor can be provided. It has the advantage that the photosensitive wavelength range can be freely controlled by selecting a pigment, and thus has been rapidly commercialized in recent years. However, such a conventional electrophotographic photoreceptor cannot be said to be sufficient in terms of sensitivity and potential stability upon repeated use, and only very few materials have been put to practical use.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel photoconductive material, and to provide an electrophotographic photoreceptor having practical high sensitivity characteristics and stable potential characteristics in repeated use. An object of the present invention is to provide an electrophotographic apparatus and a facsimile provided with the electrophotographic photosensitive member.

[0005]

According to the present invention, an organic residue selected from the group consisting of an organic residue represented by the following general formula (1) and an organic residue represented by the following general formula (2) is provided on a conductive support. The group may be bonded through a bonding group, having a photosensitive layer containing an azo pigment having a structure bonded to an aromatic hydrocarbon ring or an aromatic heterocyclic ring which may have a substituent. It is composed of a characteristic electrophotographic photoreceptor. General formula (1)

Embedded image In the formula, X ₁ represents a residue necessary for forming an aromatic hydrocarbon ring or an aromatic hetero ring which may have a substituent by condensing with a benzene ring, and R ₁ and R ₂ are the same Or differently, a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group, an aryl group, a heterocyclic group or a cyclic amino group containing a nitrogen atom to which R ₁ and R ₂ are bonded in the ring. , Z represents an oxygen atom or a sulfur atom. General formula (2)

Embedded image

More specific examples of the organic residue represented by the general formula (1) and the organic residue represented by the general formula (2) include the following formulas.

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Embedded image In the above formula, R ₁ , R ₂ and Z have the same meanings as in the general formula (1), and R ₄ represents a substituent at X ₁ in the general formula (1).

The organic residue represented by the general formula (1) and the organic residue represented by the general formula (2) will be specifically described. In the formula, X ₁ is condensed with a benzene ring to have a substituent. Residues necessary for forming an aromatic hydrocarbon ring or an aromatic heterocyclic ring such as a naphthalene ring, an anthracene ring, a carbazole ring, a benzocarbazole ring, a dibenzofuran ring, a benzonaphthofuran ring, a fluorene ring, etc. And
Examples of the substituent for X ₁ represented by R ₄ include an alkyl group such as methyl and ethyl, an alkoxy group such as methoxy and ethoxy, a halogen atom such as a fluorine atom, a bromine atom and an iodine atom, a halomethyl group such as trifluoromethyl, and a nitro group. And a cyano group.

R ₁ and R ₂ are a hydrogen atom, an optionally substituted alkyl group such as methyl, ethyl, propyl and butyl, an aralkyl group such as benzyl, phenethyl and naphthylmethyl, phenyl, diphenyl, naphthyl and anthryl Aryl groups such as pyridine, thienyl, furyl,
A heterocyclic group such as thiazolyl, carbazolyl, dibenzofuryl, benzimidazolyl, and benzothiazolyl; or a cyclic amino group containing a nitrogen atom to which R ₁ and R ₂ are bonded in a ring, and a substituent of the alkyl group is a fluorine atom or a bromine. Atom, halogen atom such as iodine atom, nitro group, cyano group, etc .;
Alkyl group such as methyl, ethyl and propyl, alkoxy group such as methoxy and ethoxy, halogen atom such as fluorine atom, bromine atom and iodine atom, and alkyl such as dimethylamino and diethylamino. Examples include an amino group, a phenylcarbamoyl group, a nitro group, a cyano group, and a halomethyl group such as trifluoromethyl.

As the cyclic amino group containing a nitrogen atom in the ring, pyrrol, pyrroline, pyrrolidine, pyrrolidone, indoline, isoindole, carbazole, benzoindole, imidazole, pyrazole, pyrazoline, Cyclic amino groups derived from oxazine, phenoxazine, benzocarbazole and the like are mentioned. Examples of the substituent include alkyl groups such as methyl, ethyl and propyl, alkoxy groups such as methoxy and ethoxy, fluorine atom, bromine atom and iodine. Examples include a halogen atom such as an atom, a nitro group, a cyano group, and a halomethyl group such as trifluoromethyl.

It is preferable that one of R ₁ and R ₂ is a hydrogen atom. When R ₁ is a hydrogen atom, R ₂ is an alkyl group, an aralkyl group or an aryl group which may have a substituent. And an aryl group which may have a substituent, particularly a phenyl group which may have a substituent is most preferable in terms of sensitivity and durability.

Z represents an oxygen atom or a sulfur atom.

An organic residue represented by the general formula (1) binds:
An aromatic hydrocarbon ring or an aromatic heterocyclic ring which may have a substituent may be bonded through a bonding group, such as benzene, naphthalene, fluorene, phenanthrene, anthracene, pyrene, furan, thiophene, pyridine, Indole, benzothiazole, carbazole, acridone, dibenzothiophene, benzoxazol, benzotriazole, oxadiazol, thiazol, and the like. Examples of those bonded by a non-aromatic group include triphenylamine, diphenylamine, N-methyldiphenylamine, biphenyl, ta-phenyl, binaphthyl, fluorenone, phenanthrenequinone, anthraquinone, benzanthrone, diphenyloxadiazol, Phenylbenzoxazo- , Diphenylmethane, diphenyl sulfone, diphenyl ether - ether, benzophenone, stilbene, distyryl benzene, tetraphenyl -p- phenylenediamine, etc. tetraphenyl benzidine and the like. Examples of the substituent which may have an aromatic hydrocarbon ring or an aromatic heterocyclic ring which may be bonded through the bonding group include methyl, ethyl, an alkyl group such as propyl, methoxy, an alkoxy group such as ethoxy, Examples include a halogen atom such as a fluorine atom, a bromine atom and an iodine atom, a dialkylamino group such as dimethylamino and diethylamino, a hydroxy group, a nitro group, a cyano group, a halomethyl group, and a substituted azo group represented by the general formula (7).

In -N = N-Cp represented by the general formula (7), Cp represents a coupler residue having a phenolic OH group, and specifically includes those having the structures described below. General formula (8)

Embedded image General formula (9)

Embedded image General formula (10)

Embedded image General formula (11)

Embedded image General formula (12)

Embedded image General formula (13)

Embedded image General formula (14)

Embedded image General formula (15)

Embedded image General formula (16)

Embedded image General formula (17)

Embedded image General formula (18)

Embedded image General formula (19)

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In the above formula, X ₂ and X ₃ are condensed with a benzene ring to form an optionally substituted naphthalene ring, anthracene ring, carbazole ring, benzocarbazole ring, dibenzofuran ring, benzonaphthofuran. And a residue necessary for forming an aromatic hydrocarbon ring such as a ring or a fluorene ring or an aromatic heterocyclic ring.

R ₅ and R ₆ are the same or different and each is a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group, an aryl group, a heterocyclic group, or a nitrogen atom to which R ₅ and R ₆ bind. And R ₇ and R ₈ are the same or different and each represent a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group, an aryl group or a heterocyclic group; R ₉ represents an optionally substituted alkyl group, aralkyl group, aryl group or heterocyclic group.

Y ₁ represents a divalent hydrocarbon group or a heterocyclic group which may have a substituent, including Y ₁

Embedded image as,

Embedded image

Embedded image

Embedded image

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Embedded image And Y ₂ represents a divalent aromatic hydrocarbon group which may have a substituent, and a group such as o-phenylene, o-naphthylene, 1,2-anthrylene, 9,10-phenanthrylene and the like. And Y ₃ may have a substituent 2
Having a bivalent aromatic hydrocarbon group or a nitrogen atom in the ring
A divalent heterocyclic group, o-phenylene, o-naphthylene, 1,2-anthrylene, 9,10-phenanthrylene, 3,4-pyrazoldiyl, 2,3-pyridinediyl, 4,5-pyrimidinediyl, 6,7-indazoldiyl, 5,6-benzimidazoldiyl, 6,7-
Groups such as quinolinediyl;

B is an oxygen atom, a sulfur atom, an N-substituted or unsubstituted imino group (an N-substituent includes an optionally substituted alkyl group, an aralkyl group, and an aryl group; ).

The alkyl group in the above expression includes groups such as methyl, ethyl, propyl and butyl, the aralkyl group includes groups such as benzyl, phenethyl and naphthylmethyl, and the aryl group includes phenyl and diphenyl. , Naphthyl, anthryl, and the like, and examples of the heterocyclic group include pyridyl, thienyl, furyl, thiazolyl, carbazolyl, dibenzofuryl, benzimidazolyl, and benzothiazolyl. Is pyrrol, pyrroline,
Groups such as pyrrolidine, pyrrolidone, indole, indoline, isoindole, carbazole, benzoindole, imidazole, pyrazol, pyrazoline, oxazine, phenoxazine, and benzocarbazole;
Further, as a substituent, an alkyl group such as methyl, ethyl and propyl, a methoxy group and an alkoxy group such as ethoxy,
Fluorine atom, chlorine atom, bromine atom, halogen atom such as iodine atom, dimethylamino, alkylamino group such as diethylamino, phenylcarbamoyl group, nitro group,
Examples include a halomethyl group such as a cyano group and trifluoromethyl.

Tables 1 to 49 show typical examples of the azo pigments used in the present invention. The following basic type 1, basic type 2, basic type 3 and basic type 4 are provided for notation, and the specific structure of the azo pigment is shown by this. Basic type 1

Embedded image (In the formula, Ar, X ₁ , R ₁ , R ₂ , Z and n have the same meanings as described above.) However, the organic residue portion represented by the general formula (1) (-N = N-
Are expressed as A. Basic type 2

Embedded image (In the formula, Ar, X ₁ , R ₁ , R ₂ , Z and n have the same meanings as described above.) However, the organic residue portion represented by the general formula (1) (-N = N-
Portions) except for the representation of the part indicated by A _1, Cp as A _2. Basic type 3

Embedded image (In the formula, Ar, X ₁ , R ₁ , R ₂ , Z and n are as defined above.) However, the organic residue portion represented by the general formula (2) (-N = N-
Are expressed as A. Basic type 4

Embedded image (In the formula, Ar, X ₁ , R ₁ , R ₂ , Z and n are as defined above.) However, the organic residue portion represented by the general formula (2) (-N = N-
Portions) except for the representation of the part indicated by A _1, Cp as A _2.

[Table 1]

[Table 2]

[Table 3]

[Table 4]

[Table 5]

[Table 6]

[Table 7]

[Table 8]

[Table 9]

[Table 10]

[Table 11]

[Table 12]

[Table 13]

[Table 14]

[Table 15]

[Table 16]

[Table 17]

[Table 18]

[Table 19]

[Table 20]

[Table 21]

[Table 22]

[Table 23]

[Table 24]

[Table 25]

[Table 26]

[Table 27]

[Table 28]

[Table 29]

[Table 30]

[Table 31]

[Table 32]

[Table 33]

[Table 34]

[Table 35]

[Table 36]

[Table 37]

[Table 38]

[Table 39]

[Table 40]

[Table 41]

[Table 42]

[Table 43]

[Table 44]

[Table 45]

[Table 46]

[Table 47]

[Table 48]

[Table 49]

[0020]

Embedded image (Wherein X ₁ , R ₁ , R ₂ and Z have the same meanings as in the general formula (1)) or a general formula (21)

Embedded image (Wherein X ₁ , R ₁ , R ₂ , and Z have the same meanings as in the general formula (1)) and can be synthesized by coupling a coupler component and a diazo component.

The coupler component has the general formula (22)

Embedded image Wherein X ₁ is as defined above, or a carboxylic acid compound represented by the general formula (23):

Embedded image And a carboxylic acid compound represented by the general formula (24) (Wherein R ₁ and R ₂ are as defined above) with urea represented by benzene, toluene, xylene, chlorobenzene, o-
Heat condensation at 80 to 200 ° C. in an aromatic solvent such as dichlorobenzene in the presence of phosphorus trichloride, or a compound of the general formula (25)

Embedded image Wherein X ₁ is as defined above, or an acid chloride compound represented by the general formula (26):

Embedded image Can be synthesized by heating the acid chloride compound represented by the formula and the ureas in an aromatic solvent.

The thus obtained coupler component and an amino compound represented by the general formula (27) Ar- (NH ₂ ) _n (wherein Ar and n have the same meaning as in the general formula (4)) are prepared by a conventional method. Or a diazonium salt of the amino compound (general formula (27)) is isolated once in the form of a salt such as a borofluoride or a zinc chloride double salt in the presence of an alkali. The obtained salt is combined with an organic solvent such as N, N-dimethylformamide, N, N-dimethylacetamide and dimethylsulfoxide in a suitable solvent in the presence of a base such as sodium acetate, pyridine, trimethylamine and triethylamine. The azo pigment can be produced by solvent-based coupling.

Further, the azo pigment used in the present invention comprises an organic residue represented by the general formula (1) and a compound represented by the general formula (2) in the same molecule.
It is sufficient that at least one organic residue selected from the organic residues represented by is used. The coupler component and another coupler component are successively coupled to the diazo component, or separately from the coupler component. Can be produced by mixing the above coupler components and performing coupling at the same time.

Synthesis Example 1 (Pigment Example 2-1) 150 ml of water was added to a 300 ml beaker.
20 ml (0.23 mol) of concentrated hydrochloric acid and the following amino compounds

Embedded image 5.9 g (0.032 mol) was added and cooled to 0 ° C., and 4.6 g (0.067 mol) of soda nitrite was added to 10 parts of water.
Keep the solution dissolved in milliliters at 10
In minutes. After stirring for 15 minutes, the mixture was filtered with carbon, and 10.5 g of sodium borofluoride was added to the solution.
(0.096 mol) in 90 ml of water was added dropwise with stirring, and the precipitated borofluoride was collected by filtration.
After washing with cold water, it was washed with acetonitrile and dried at room temperature under reduced pressure. Yield 9.5 g, 78% yield

Next, 500 ml of DMF was placed in a 1 liter beaker, and the following coupler components were added.

Embedded image After dissolving 12.9 g (0.042 mol) and cooling the solution to 5 ° C., 7.6 g (0.020 mol) of the previously obtained borofluoride was used.
Mol), and then 5.1 g of triethylamine
(0.050 mol) was added dropwise over 5 minutes. After stirring for 2 hours, the precipitated pigment was collected by filtration, washed four times with DMF and three times with water, and then freeze-dried. 14.1 g, 86% yield

[0026]

Synthesis Example 2 (Pigment example 2-93) 150 ml water in a 300 ml beaker
20 ml (0.23 mol) of concentrated hydrochloric acid and the following amino compounds

Embedded image 5.9 g (0.032 mol) was added and cooled to 0 ° C., and 4.6 g (0.067 mol) of soda nitrite was added to 10 parts of water.
Keep the solution dissolved in milliliters at 10
The solution was dropped in a minute. After stirring for 15 minutes, the mixture was filtered with carbon, and 10.5 g of sodium borofluoride was added to the solution.
(0.096 mol) in 90 ml of water was added dropwise with stirring, and the precipitated borofluoride was collected by filtration.
After washing with cold water, it was washed with acetonitrile and dried at room temperature under reduced pressure. Yield 9.5 g, 78% yield

Next, 500 ml of DMF was placed in a 1 liter beaker, and the following coupler components were added.

Embedded image After dissolving 12.9 g (0.042 mol) and cooling the solution to 5 ° C., 7.6 g (0.020 mol) of the previously obtained borofluoride was used.
Mol), and then 5.1 g of triethylamine
(0.050 mol) was added dropwise over 5 minutes. After stirring for 2 hours, the precipitated pigment was collected by filtration, washed four times with DMF and three times with water, and then freeze-dried. 14.1 g, 86% yield

[0029]

The electrophotographic photosensitive member of the present invention has a photosensitive layer containing an azo pigment having the above-mentioned specific structure on a conductive support. Although the form of the photosensitive layer may take any known form, the photosensitive layer containing the azo pigment is used as a charge generation layer, and a function-separated type in which a charge transport layer containing a charge transport material is laminated thereon. Photosensitive layers are particularly preferred.

The charge generation layer can be formed by applying a coating solution obtained by dispersing the azo pigment together with a binder resin in a suitable solvent onto a conductive support by a known method. Is desirably a thin film layer having a thickness of, for example, 5 μm or less, preferably 0.1 to 1 μm. The binder resin used at this time is selected from a wide range of insulating resins or organic photoconductive polymers, but polyvinyl butyral, polyvinyl benzal, polyarylate, polycarbonate, polyester, phenoxy resin, cellulose resin, acrylic resin , Polyurethane and the like are used, and the amount used is 8 in terms of the content in the charge generation layer.
0% by weight or less, preferably 40% by weight or less. The solvent used is preferably selected from those which dissolve the resin and do not dissolve the charge transport layer and the undercoat layer described below. Specifically, ethers such as tetrahydrofuran and 1,4-dioxane, ketones such as cyclohexanone and methyl ethyl ketone, amides such as N, N-dimethylformamide, esters such as methyl acetate and ethyl acetate, toluene, Examples include aromatics such as xylene and chlorobenzene, alcohols such as methanol, ethanol, and 2-propanol; and aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene.

The charge transport layer is stacked on or below the charge generation layer, and has a function of receiving charge carriers from the charge generation layer in the presence of an electric field and transporting the carriers. The charge transporting layer is formed by dissolving a charge transporting material in a solvent together with a suitable binder resin as required and applying the solution. The film thickness is generally 5 to 40 μm, but 15 to 30 μm.
Is preferred. The charge transporting substance includes an electron transporting substance and a hole transporting substance.
Electron-withdrawing substances such as 4,7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, chloranil, tetracyanoquinodimethane and the like, and those obtained by polymerizing these electron-withdrawing substances. Examples of the hole-transporting substance include polycyclic aromatic compounds such as pyrene and anthracene, carbazole compounds, indole compounds, imidazole compounds,
Oxazole, thiazole, oxadiazol,
Heterocyclic compounds such as pyrazole, pyrazoline, thiadiazole and triazole compounds, p-diethylaminobenzaldehyde-N, N-diphenylhydrazone, N, N-diphenylhydrazino-3-methylidene-
Hydrazone compounds such as 9-ethylcarbazole, α
Styryl compounds such as -phenyl-4'-N, N-diphenylaminostilbene, 5- [4- (di-p-tolylamino) benzylidene] -5H-dibenzo [a, d] cycloheptene, benzidine compounds, triary- Methane compounds, triphenylamines or polymers having a group consisting of these compounds in the main or side chain
(For example, poly-N-vinyl carbazole, polyvinyl anthracene, etc.). In addition to these organic charge transport materials, inorganic materials such as selenium, selenium-tellurium, amorphous silicon, and cadmium sulfide can be used. These charge transport materials can be used alone or in combination of two or more. When the charge transport material does not have a film-forming property, an appropriate binder can be used. Specifically, acrylic resin, polyarylate, polyester, polycarbonate, polystyrene,
Examples thereof include insulating resins such as acrylonitrile styrene copolymer, polyacrylamide, polyamide, and chlorinated rubber, and organic photoconductive polymers such as poly-N-vinylcarbazole and polyvinylanthracene.

As the conductive support on which the photosensitive layer is formed, for example, aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold and platinum are used. In addition, plastics (eg, polyethylene,
A support or conductive particles obtained by coating conductive particles (for example, carbon black, silver particles, etc.) and a suitable binder resin on a plastic or metal substrate or a conductive material such as polypropylene or polyvinyl chloride, polyethylene terephthalate, acrylic resin, etc. A support impregnated with the resin can be used.

An undercoat layer having a barrier function and an adhesive function can be provided between the conductive support and the photosensitive layer. The undercoat layer can be formed of casein, polyvinyl alcohol, nitrocellulose, polyamide (nylon 6, nylon 66, nylon 610, copolymer nylon, alkoxymethylated nylon, etc.), polyurethane, aluminum oxide, or the like. The thickness of the undercoat layer is 5 μm or less, preferably 0.1 to 3 μm.

Another specific example of the present invention is an electrophotographic photosensitive member in which the above-mentioned azo pigment and a charge transporting substance are contained in the same layer. In this case, a charge transfer complex composed of poly-N-vinylcarbazole and trinitrofluorenone can be used as the charge transport material. The electrophotographic photoreceptor of this example can be formed by applying and drying a liquid in which the azo pigment and the charge transfer complex are dispersed in an appropriate resin solution. In any of the electrophotographic photoreceptors, the crystal form of the azo pigment may be amorphous or crystalline, and if necessary, a combination of two or more of the azo pigments or a known charge generation It is also possible to use in combination with a substance.

The electrophotographic photosensitive member of the present invention can be used not only for an electrophotographic copying machine but also for a laser beam printer,
RT printer, LED printer, LCD printer,
It can be widely used in electrophotographic applications such as laser plate making and facsimile.

Further, the present invention comprises an electrophotographic apparatus provided with the electrophotographic photoreceptor of the present invention.

Further, the present invention comprises an electrophotographic apparatus provided with the electrophotographic photosensitive member of the present invention and a facsimile having means for receiving image information from a remote terminal.

Next, an electrophotographic apparatus provided with the electrophotographic photosensitive member of the present invention and a facsimile will be described. FIG.
FIG. 1 shows a schematic configuration of a general transfer type electrophotographic apparatus using the drum type photoreceptor of the present invention. In FIG. 1, reference numeral 1 denotes a drum-type photosensitive member as an image carrier, which is driven to rotate around an axis 1a in a direction of an arrow at a predetermined peripheral speed. The photoreceptor 1 is uniformly charged with a predetermined positive or negative potential on its peripheral surface by a charging means 2 during the rotation process, and then, in an exposure section 3, a light image exposure L (slit exposure / Laser
Beam scanning exposure). As a result, an electrostatic latent image corresponding to the exposure image is sequentially formed on the peripheral surface of the photoconductor. The electrostatic latent image is then toner-developed by the developing means 4, and the toner-developed image is rotated by the transfer means 5 between the photosensitive member 1 and the transfer means 5 from a paper feeding unit (not shown). Are sequentially transferred onto the surface of the transfer material P fed in synchronization with the transfer. The transfer material P having undergone the image transfer is separated from the photoreceptor surface, introduced into the image fixing means 8 and subjected to image fixing to be printed out as a copy (copy) outside the machine. The surface of the photoreceptor 1 after the image transfer is transferred by a cleaning means 6 to a transfer residual toner.
Is removed, the surface is cleaned, the pre-exposure means 7 removes electricity, and is repeatedly used for image formation. Photoconductor 1
As the uniform charging means 2, a corona charging device is generally widely used. Also, the corona transfer means is generally widely used for the transfer device 5. As an electrophotographic apparatus, a plurality of components such as the above-described photoreceptor, developing means, and cleaning means are integrally connected as an apparatus unit, and this unit is detachably attached to the apparatus body. You may comprise. For example, the photoreceptor 1 and the cleaning means 6 may be integrated into one apparatus unit, and may be configured to be detachable using guide means such as rails of the apparatus body. At this time, the above-described device unit may be provided with a charging unit and / or a developing unit. Further, the light image exposure L is performed by using an electrophotographic apparatus as a copying machine or a printer.
In the case of using as a light source, reflected light or transmitted light from a document is used, or a document is read and converted into a signal, and scanning of a laser beam, driving of a light emitting diode array, or liquid crystal shutter is performed according to the signal. This is performed by driving an array or the like. Also, a facsimile printer
In the case of using the light image exposure, the light image exposure L is an exposure for printing the received data.

FIG. 2 is a block diagram showing one example of this case. The controller 10 controls the image reading section 9 and the printer 18. The entire controller 10 is C
It is controlled by the PU16. The read data from the image reading unit is transmitted to the partner station through the transmission circuit 12. Data received from the partner station is sent to the printer 18 through the receiving circuit 11. Predetermined image data is stored in the image memory. The printer controller 17 controls the printer 18. 13 is a telephone. Line 14
(Received from a remote terminal connected via a line) are demodulated by the receiving circuit 11, and then the CPU 16 performs signal processing of the image information and sequentially stores the processed signals in the image memory 15. . When at least one page of the image is stored in the memory 15, the image of the page is stored. The CPU 16 reads out one page of the image information from the memory 15 and sends out one page of the imaged information to the printer controller 17. Upon receiving one page of image information from the CPU 16, the printer controller 17 controls the printer 18 to record the image information of the page. It should be noted that the CPU 16 has a printer
During recording by 18, the next page is being received.
As described above, image reception and recording are performed.

[0041]

【Example】

Examples 1 to 82 On an aluminum support, 5 g of methoxymethylated nylon (weight average molecular weight 32,000) and 10 g of alcohol-soluble copolymerized nylon (weight average molecular weight 29,000) were added to methanol 95.
The solution dissolved in g was applied with a Myr bar to form an undercoat layer having a thickness of 1 μm after drying.

Next, 5 g of Pigment Example 2-1 was added to 95 g of cyclohexanone to give polyvinyl benzal (with a degree of benzalization of 7).
(5% or more) is added to the solution in which 2 g is dissolved, and 2
Dispersed for 0 hours. This dispersion was applied on a previously formed undercoat layer with a Myr bar so as to have a thickness of 0.2 μm after drying, and dried to form a charge generation layer.

Next, a styryl compound represented by the following structural formula

Embedded image 5 g of polymethyl methacrylate (weight average molecular weight 10
5 g was dissolved in 40 g of chlorobenzene, and this was coated on the charge generating layer with a Myer bar so that the film thickness after drying was 20 μm, and dried to form a charge transport layer. Was prepared.

The electrophotographic photoreceptors corresponding to Examples 2-82 were prepared in exactly the same manner, except that the pigments of the other pigment examples were used instead of Pigment Example 2-1.

The produced electrophotographic photosensitive member was used by Kawaguchi Electric Co., Ltd.
Was negatively charged by a corona discharge of -5 KV using an electrostatic copying paper tester Model SP-428, and was held for 1 second in a dark place, and then exposed at an illuminance of 10 lux using a halogen lamp to evaluate charging characteristics. . As the charging characteristics, the surface potential (V ₀ ) and the exposure amount (E1 / 2) required for the surface potential after leaving in a dark place to attenuate to １ ／ were measured. The results are shown. Example 1 Pigment Example _{2-1 V 0: -720V, E1 /} 2: 2.
9 Looks seconds Example 2 pigment Example _{1-4 V 0: -720V, E1 /} 2: 2.
8 lux · sec Example 3 Pigment Example _{1-5 V 0: -680V, E1 /} 2: 4.
3 looks · second Example 4 Pigment Example 2-4 V ₀ : -690 V, E1 / 2: 3.
3 Looks seconds Example 5 Pigment example _{2-7 V 0: -710V, E1 /} 2: 2.
3 Looks seconds Example 6 pigment Example _{2-9 V 0: -690V, E1 /} 2: 3.
8 Looks seconds Example 7 pigment Example _{2-13 V 0: -710V, E1 /} 2: 1.
9 Looks seconds Example 8 pigment Example _{2-14 V 0: -710V, E1 /} 2: 3.
8 Looks seconds Example 9 pigment Example _{2-17 V 0: -720V, E1 /} 2: 2.
4 lux · sec Example 10 Pigment Example _{2-20 V 0: -700V, E1 /} 2: 3.
3 Looks seconds Example 11 pigment Example _{2-22 V 0: -730V, E1 /} 2: 3.
0 lux · sec Example 12 Pigment Example _{2-25 V 0: -710V, E1 /} 2: 4.
5 lux · sec Example 13 Pigment Example _{2-27 V 0: -700V, E1 /} 2: 1.
8 Looks seconds Example 14 pigment Example _{2-30 V 0: -690V, E1 /} 2: 2.
2 looks · second Example 15 Pigment example 2-32 V ₀ : −730 V, E1 / 2: 3.
1 lux · sec Example 16 Pigment Example _{2-34 V 0: -710V, E1 /} 2: 3.
6 Looks seconds Example 17 pigment Example _{2-40 V 0: -690V, E1 /} 2: 2.
0 Looks seconds Example 18 pigment Example _{2-42 V 0: -710V, E1 /} 2: 4.
1 lux-seconds Example 19 pigment Example _{2-43 V 0: -720V, E1 /} 2: 2.
6 lux · sec Example 20 Pigment Example _{2-45 V 0: -680V, E1 /} 2: 3.
5 lux-seconds Example 21 pigment Example _{2-47 V 0: -700V, E1 /} 2: 2.
8 lux · sec Example 22 Pigment Example _{2-48 V 0: -710V, E1 /} 2: 3.
8 lux / s Example 23 Pigment Example 2-50 V ₀ : -690 V, E1 / 2: 1.
7 Looks seconds Example 24 pigment Example _{2-53 V 0: -710V, E1 /} 2: 1.
4 Looks seconds Example 25 pigment Example _{2-56 V 0: -700V, E1 /} 2: 4.
0 Looks seconds Example 26 pigment Example _{2-58 V 0: -710V, E1 /} 2: 3.
3 lux · sec Example 27 Pigment Example _{2-60 V 0: -700V, E1 /} 2: 1.
6 Looks seconds Example 28 pigment Example _{2-63 V 0: -700V, E1 /} 2: 3.
2 Looks seconds Example 29 pigment Example _{2-65 V 0: -710V, E1 /} 2: 2.
7 Looks seconds Example 30 pigment Example _{2-68 V 0: -720V, E1 /} 2: 2.
4 lux · sec Example 31 Pigment Example _{2-70 V 0: -700V, E1 /} 2: 3.
9 lux · sec Example 32 Pigment Example _{2-73 V 0: -710V, E1 /} 2: 2.
4 lux · sec Example 33 Pigment Example _{2-76 V 0: -700V, E1 /} 2: 3.
3 lux · sec Example 34 Pigment Example _{2-80 V 0: -680V, E1 /} 2: 3.
9 Looks seconds Example 35 pigment Example _{2-83 V 0: -720V, E1 /} 2: 2.
6 Looks seconds Example 36 pigment Example _{2-87 V 0: -690V, E1 /} 2: 2.
0 Looks seconds Example 37 pigment Example _{2-89 V 0: -710V, E1 /} 2: 3.
1 lux · sec Example 38 Pigment Example _{3-1 V 0: -730V, E1 /} 2: 3.
4 Looks seconds Example 39 pigment Example _{3-3 V 0: -690V, E1 /} 2: 2.
7 lux · sec Example 40 Pigment Example _{3-7 V 0: -700V, E1 /} 2: 4.
3 lux · sec Example 41 Pigment Example _{4-2 V 0: -710V, E1 /} 2: 3.
9 lux · sec Example 42 Pigment Example _{2-93 V 0: -710V, E1 /} 2: 3.
9 lux · sec Example 43 Pigment Example _{1-9 V 0: -710V, E1 /} 2: 3.
6 lux · sec Example 44 Pigment Example _{1-10 V 0: -700V, E1 /} 2: 4.
8 lux · sec Example 45 Pigment Example _{2-96 V 0: -690V, E1 /} 2: 3.
3 Looks seconds Example 46 pigment Example _{2-99 V 0: -710V, E1 /} 2: 2.
4 Looks seconds Example 47 pigment example _{2-101 V 0: -690V, E1 /} 2: 4.
3 Looks seconds Example 48 pigment example _{2-105 V 0: -700V, E1 /} 2: 2.
4 Looks seconds Example 49 pigment example _{2-106 V 0: -700V, E1 /} 2: 4.
6 lux · sec Example 50 Pigment Example _{2-109 V 0: -710V, E1 /} 2: 3.
4 lux · sec Example 51 Pigment Example _{2-112 V 0: -700V, E1 /} 2: 3.
9 lux · sec Example 52 Pigment Example _{2-114 V 0: -720V, E1 /} 2: 3.
6 lux · sec Example 53 Pigment Example _{2-117 V 0: -680V, E1 /} 2: 4.
1 lux-seconds Example 54 pigment example _{2-119 V 0: -700V, E1 /} 2: 2.
0 Looks seconds Example 55 pigment example _{2-122 V 0: -690V, E1 /} 2: 2.
3 lux · sec Example 56 Pigment Example _{2-124 V 0: -710V, E1 /} 2: 3.
7 Looks seconds Example 57 pigment example _{2-126 V 0: -710V, E1 /} 2: 3.
9 Looks seconds Example 58 pigment example _{2-132 V 0: -710V, E1 /} 2: 2.
9 Looks seconds Example 59 pigment example _{2-134 V 0: -710V, E1 /} 2: 4.
7 lux · sec Example 60 Pigment Example _{2-135 V 0: -700V, E1 /} 2: 3.
6 Looks seconds Example 61 pigment example _{2-137 V 0: -690V, E1 /} 2: 3.
9 lux · sec Example 62 Pigment Example _{2-139 V 0: -690V, E1 /} 2: 3.
2 looks · second Example 63 Pigment example 2-140 V ₀ : -700 V, E1 / 2: 4.
1 lux-seconds Example 64 pigment example _{2-142 V 0: -680V, E1 /} 2: 2.
7 Looks seconds Example 65 pigment example _{2-145 V 0: -700V, E1 /} 2: 2.
4 lux · sec Example 66 Pigment Example _{2-148 V 0: -680V, E1 /} 2: 4.
0 Looks seconds Example 67 pigment example _{2-150 V 0: -720V, E1 /} 2: 4.
3 lux · sec Example 68 Pigment Example _{2-152 V 0: -700V, E1 /} 2: 1.
9 looks · second Example 69 Pigment example 2-155 V ₀ : -700 V, E1 / 2: 4.
2 lux · sec Example 70 Pigment Example _{2-157 V 0: -710V, E1 /} 2: 3.
7 lux · sec Example 71 Pigment Example _{2-160 V 0: -720V, E1 /} 2: 3.
4 lux · sec Example 72 Pigment Example _{2-162 V 0: -700V, E1 /} 2: 4.
4 lux · sec Example 73 Pigment Example _{2-165 V 0: -720V, E1 /} 2: 3.
4 lux · sec Example 74 Pigment Example _{2-168 V 0: -700V, E1 /} 2: 3.
3 Looks seconds Example 75 pigment example _{2-172 V 0: -690V, E1 /} 2: 3.
9 Looks seconds Example 76 pigment example _{2-175 V 0: -700V, E1 /} 2: 2.
9 Looks seconds Example 77 pigment example _{2-179 V 0: -690V, E1 /} 2: 2.
6 Looks seconds Example 78 pigment example _{2-181 V 0: -710V, E1 /} 2: 3.
7 Looks seconds Example 79 pigment Example _{3-8 V 0: -700V, E1 /} 2: 4.1
Lux · sec Example 80 Pigment Example _{3-10 V 0: -700V, E1 /} 2: 3.
6 lux · sec Example 81 Pigment Example _{3-14 V 0: -700V, E1 /} 2: 4.
8 lux · sec Example 82 Pigment Example _{4-5 V 0: -720V, E1 /} 2: 3.9
Looks Second

Comparative Examples 1 to 4 The pigment used in the above Examples was Comparative Pigment 1 represented by the following structural formula.
An electrophotographic photoreceptor was prepared in exactly the same manner as in this example, except that the charge was changed to 4, and the charging characteristics were evaluated in the same manner. Comparative pigment 1

Embedded image Comparative pigment 2

Embedded image Comparative pigment 3

Embedded image Comparative pigment 4

Embedded image Comparative Example 1 (corresponding to Examples 5 and 10) Comparative Pigment 1 V ₀ : −680 V, E1 / 2: 4.2 lux · s Comparative Example 2 (corresponding to Examples 14 and 55) Comparative Pigment 2 V ₀ : − 710 V, E1 / 2: 4.8 lux-second Comparative Example 3 (corresponding to Examples 21 and 62) Comparative Pigment 3 V ₀ : -720 V, E1 / 2: 6.9 lux-second Comparative Example 4 (Example 27) And 68) Comparative pigment 4 V ₀ : −710 V, E1 / 2: 3.7 lux · sec From these results, it can be seen that the electrophotographic photoreceptor of the present invention has sufficient chargeability and excellent sensitivity.

Examples 83 to 92 The electrophotographic photosensitive member prepared in Example 5 was provided with a corona charger of -6.5 KV, an exposure optical system, a developing device, a transfer charger, a charge removing exposure optical system, and a cleaner. To a cylinder of an electrophotographic copying machine. Initial dark potential V _D and the light portion potential V _L respectively set -700 V, in the vicinity of -200 V,
The amount of change in the dark area potential (Δ
V _D ) and the variation (ΔV _L ) of the light portion potential were measured. The electrophotographic photoreceptors prepared in Examples 14, 23, 27, 38, 46, 54, 62, 68 and 71 were similarly evaluated. The results are shown. A negative sign in the fluctuation amount of the potential indicates a decrease in the absolute value of the potential, and a positive sign indicates an increase in the absolute value of the potential. Example 83 (for the electrophotographic photosensitive member prepared in Example 5) ΔV _D = 0 V, ΔV _L : +10 V Example 84 (for the electrophotographic photosensitive member prepared in Example 14) ΔV _D : −10 V, ΔV _L : +5 V Example 85 (for the electrophotographic photoconductor prepared in Example 23) ΔV _D : −15 V, ΔV _L : +5 V Example 86 (for the electrophotographic photoconductor prepared in Example 27) ΔV _D : 0 V, ΔV _L : +5 V Example 87 (for the electrophotographic photosensitive member prepared in Example 38) ΔV _D : −10 V, ΔV _L : +20 V Example 88 (for the electrophotographic photosensitive member prepared in Example 46) ΔV _D : −5 V, ΔV _L : +10 V Example 89 (for the electrophotographic photosensitive member prepared in Example 54) ΔV _D : −10 V, ΔV _L : +5 V Example 90 (electrophotographic photosensitive member prepared in Example 62) target the body) ΔV _D: -15V ΔV _L: + 5V Example 91 (subject an electrophotographic photoreceptor prepared in Example _{68) ΔV D: 0V, ΔV} L: + 15V Example 92 (subject an electrophotographic photoreceptor prepared in Example 71) [Delta] V _D: -10 V, ΔV _L : +20 V

Comparative Examples 5 and 6 The amount of potential fluctuation when the electrophotographic photosensitive members prepared in Comparative Examples 1 and 4 were repeatedly used in the same manner as in Example 83 was measured. Comparative Example 5 (for the electrophotographic photosensitive member prepared in Comparative Example 1,
ΔV _D : −25 V, ΔV _L : +30 V Comparative Example 6 (for the electrophotographic photosensitive member prepared in Comparative Example 4,
(Corresponding to Examples 86 and 91) ΔV _D : -10 V, ΔV _L : +45 V

Example 93 An undercoat layer of polyvinyl alcohol having a thickness of 0.5 μm was formed on an aluminum surface of an aluminum-deposited polyethylene terephthalate film. 5 g of the pigment of Pigment Example 2-64 was added to 95 g of cyclohexanone and 2 g of butyral resin (butyralization degree: 63 mol%), and the resulting dispersion was applied on the undercoat layer and dried. And a film thickness of 0.2 μm
Was formed.

Next, a hydrazone compound of the following structural formula

Embedded image 5 g and polycarbonate (weight average molecular weight 55,000) 5
g in 40 g of tetrahydrofuran was applied onto the charge generation layer and dried to form a charge transport layer having a thickness of 20 μm. With respect to the produced electrophotographic photosensitive member, the charging characteristics and the durability characteristics were measured by the same methods as in Examples 1 and 83. The results are shown. V ₀ : -710 V, E1 / 2: 2.9 lux · sec ΔV _D : −5 V, ΔV _L : +15 V

Example 94 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 93 except that Pigment Example 2-159 was used. The results are shown. V ₀ : -700 V, E1 / 2: 2.5 lux · sec ΔV _D : 0 V, ΔV _L : +5 V

Example 95 An undercoat layer of polyvinyl alcohol having a thickness of 0.5 μm was formed on an aluminum surface of an aluminum-deposited polyethylene terephthalate film. 5 g of the pigment of Pigment Example 2-53 was added to a solution of 2 g of poly-p-fluorovinylbenzal (benzal excess of 75% or more) in 95 g of tetrahydrofuran, and the resulting dispersion was dispersed and prepared. The resultant was coated and dried to form a charge generation layer having a thickness of 0.2 μm.

Next, a triarylamine compound having the following structural formula

Embedded image 5 g and polycarbonate (weight average molecular weight 55,000) 5
g of chlorobenzene dissolved in 40 g of chlorobenzene was applied on the charge generation layer and dried to form a charge transport layer having a thickness of 20 μm. With respect to the produced electrophotographic photosensitive member, the charging characteristics and the durability characteristics were measured by the same methods as in Examples 1 and 83. The results are shown. V ₀ : -700 V, E1 / 2: 1.2 lux · sec ΔV _D : 0 V, ΔV _L : +5 V

Example 96 An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 95 except that Pigment Example 2-145 was used. The results are shown. _{V 0: -710V, E1 / 2} : 2.3 lux-seconds _{ΔV D: -5V, ΔV L:} + 5V

Examples 97 and 98 An electrophotographic photosensitive member was prepared by applying the charge generation layer and the charge transport layer of the electrophotographic photosensitive member prepared in Examples 17 and 58 in reverse order, and charged in the same manner as in Example 1. The properties were evaluated.
However, the charging was positive. Example _{97 V 0: + 690V, E1} / 2: 2.8 lux · sec Example _{98 V 0: + 700V, E1} / 2: 3.1 lux · sec

Example 99 5 g of 2,4,7-trinitro-9-fluorenone and poly-4,4'-dioxydiphenyl-2,2-propane carbonate were placed on the charge generation layer prepared in Example 95. A solution prepared by dissolving 5 g of (molecular weight 300,000) in 50 g of tetrahydrofuran was applied with a Myer bar, and a charge transport layer having a thickness of 18 μm after drying was formed. The charging characteristics of the produced electrophotographic photosensitive member were evaluated in the same manner as in Example 1. However,
The charging was positive. V ₀ : + 720V, E1 / 2: 2.1 lux / sec

Example 100 5 g of 2,4,7-trinitro-9-fluorenone and poly-4,4'-dioxydiphenyl-2,2-propane carbonate were deposited on the charge generation layer prepared in Example 54. A solution prepared by dissolving 5 g of (molecular weight 300,000) in 50 g of tetrahydrofuran was applied with a Myer bar, and a charge transport layer having a thickness of 18 μm after drying was formed. The charging characteristics of the produced electrophotographic photosensitive member were evaluated in the same manner as in Example 1. However,
The charging was positive. V ₀ : +710 V, E1 / 2: 2.9 lux / sec

Examples 101 and 102 0.5 g of the pigments of Examples 2-73 and 2-165 were dispersed together with 9.5 g of cyclohexanone in a paint shaker for 5 hours. Here, 5 g of the same charge transporting material as used in Example 1 and 5 g of polycarbonate were added to tetrahydrofuran 4
A solution dissolved in 0 g was added, and the mixture was further stirred for 1 hour.
The coating solution thus prepared was applied to an aluminum support with a Myer bar and dried to form a photosensitive layer having a thickness of 20 μm.
The electrophotographic photosensitive member thus produced was evaluated for charging characteristics in the same manner as in Example 1. The charging was positive. EXAMPLE _{101 V 0: + 710V, E1} / 2: 3.1 lux · sec Example _{102 V 0: + 700V, E1} / 2: 3.7 lux · sec

[0059]

According to the electrophotographic photoreceptor of the present invention, by using an azo pigment having a specific structure in the photosensitive layer, one or both of the generation efficiency and / or the injection efficiency of charge carriers in the photosensitive layer is improved. It has a remarkable effect that characteristics excellent in sensitivity and potential stability upon repeated use can be obtained, and the same remarkable effect can be obtained in an electrophotographic apparatus and a facsimile equipped with the electrophotographic photosensitive member.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a general transfer type electrophotographic apparatus.

FIG. 2 is a block diagram of a facsimile using the electrophotographic apparatus as a printer.

DESCRIPTION OF SYMBOLS 1 Drum type photoreceptor as image carrier (electrophotographic photoreceptor of the present invention) 2 Corona charging device 3 Exposure unit 4 Developing unit 5 Transfer unit 6 Cleaning unit 7 Pre-exposure unit 8 Image fixing unit L Light image exposure P Transfer material after image transfer 9 Image reading unit 10 Controller 11 Receiving circuit 12 Transmitting circuit 13 Telephone 14 Line 15 Image memory 16 CPU 17 Printer controller 18 Printer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C09B 35/039 C09B 35/039 H04N 1/29 H04N 1/29 D JP-A-2-118582 (JP, A) JP-A-57-188042 (JP, A) JP-A-3-37668 (JP, A) JP-A-4-225068 (JP, A) JP-A-4- 118661 (JP, A) JP-A-5-134436 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 5/06 340-369 CA (STN) REGISTRY (STN)

Claims (9)

(57) [Claims] An organic residue selected from the group consisting of an organic residue represented by the following general formula (1) and an organic residue represented by the following general formula (2) is provided on a conductive support with a bonding group. An electrophotographic photoreceptor having a photosensitive layer containing an azo pigment having a structure bonded to an aromatic hydrocarbon ring or an aromatic heterocyclic ring which may be substituted and which may have a substituent. . General formula (1) In the formula, X ₁ represents a residue necessary for forming an aromatic hydrocarbon ring or an aromatic hetero ring which may have a substituent by condensing with a benzene ring, and R ₁ and R ₂ are the same Or differently, a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group, an aryl group, a heterocyclic group or a cyclic amino group containing a nitrogen atom to which R ₁ and R ₂ are bonded in the ring. , Z represents an oxygen atom or a sulfur atom. General formula (2) In the formula, X ₁ , R ₁ , R ₂ and Z have the same meanings as in the general formula (1). 2. The electrophotographic photoreceptor according to claim 1, wherein the organic residue represented by the general formula (1) is an organic residue represented by the following general formula (3). General formula (3) In the formula, X ₁ and Z have the same meanings as in the general formula (1), and R ₃ represents an alkyl group, an aralkyl group or an aryl group which may have a substituent. 3. The electrophotographic photosensitive member according to claim 1, wherein the organic residue represented by the general formula (2) is an organic residue represented by the following general formula (4). General formula (4) In the formula, X ₁ , Z and R ₃ have the same meanings as in the general formula (3). 4. The electrophotographic photoreceptor according to claim 1, wherein the azo pigment is an azo pigment represented by the following general formula (5). General formula (5) In the formula, X ₁ , R ₁ , R ₂ and Z have the same meanings as in the general formula (1), and Ar is an aromatic hydrocarbon ring which may be bonded through a bonding group and which may have a substituent. Or an aromatic heterocyclic ring, and n represents an integer of 1, 2, 3 or 4. 5. The electrophotographic photosensitive member according to claim 1, wherein the azo pigment is an azo pigment represented by the following general formula (6). General formula (6) In the formula, X ₁ , R ₁ , R ₂ , Z, Ar and n have the same meanings as in the general formula (5). 6. The azo pigment has at least one organic residue selected from the group consisting of an organic residue represented by the general formula (1) and an organic residue represented by the general formula (2), and the selected organic residue. An aromatic hydrocarbon ring, which may have a substituent, may be bonded to at least one of the organic residues represented by the following general formula (7) different from the group in the same molecule through a bonding group. 2. The electrophotographic photoreceptor according to claim 1, which is an azo pigment having a structure bonded to an aromatic heterocycle. Formula (7) -N = N-Cp In the formula, Cp represents a coupler residual group having a phenolic OH group. 7. A photosensitive layer comprising at least one azo pigment selected from the group consisting of an azo pigment represented by the general formula (5) and an azo pigment represented by the general formula (6), and an organic compound represented by the general formula (1): At least one organic residue selected from the group consisting of a residue and an organic residue represented by the general formula (2) and at least one of the organic residues represented by the general formula (7) different from the selected organic residue At least one azo pigment having a structure bonded to an aromatic hydrocarbon ring or an aromatic heterocyclic ring which may be substituted and which may be bonded to each other via a bonding group in the same molecule; The electrophotographic photoreceptor according to claim 1, further comprising: 8. An electrophotographic apparatus comprising the electrophotographic photoreceptor according to claim 1. 9. A facsimile comprising: an electrophotographic apparatus provided with the electrophotographic photosensitive member according to claim 1; and means for receiving image information from a remote terminal. [0001]