JPS60184254A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body high in sensitivity enough to be brought into practice, and high in durability, and superior in resistances to heat, humidity, light fading, etc., by incorporating an azo pigment having 1-3 kinds of azo group combined with a specified coupler residue in the molecule. CONSTITUTION:The photosensitive layer of an electrophotographic sensitive body contains an azo pigment having in the molecule at least one azo group combined with the coupler residue represented by formula I in which R1 is H or optionally substd. alkyl, aryl, or hetrocyclic; R2 is optionally substd. aryl or heterocyclic; and X is a residue condensing with a benzene ring to form a naphthalene, anthracene, carbazole, dibenzofuran, or benzocarbazole ring. Above all among these azo pigments, bisazo or trisazo type pigments represented by formula II are preferable in which (p) is 2 or 3; R1, R2, and X are each same as above; A is a p-valent group representing one of (a) a hydrocarbon group having at least one benzene ring; (b) an N-contg. hydrocarbon group having at least two benzene rings, and (c) a hydrocarbon group having at least two benzene rings and at least one hetero ring. It is preferable to laminate on a conductive layer an electrostatic charge generating layer, and on this layer a charge transfer layer in this order. When needed, an adhesive layer may be formed between the conductive layer and the charge generating layer in order to enhance adhesion between them. The azo pigment is finely pulverized and then, dispersed into a proper binder soln., applied to the conductive layer, or the adhesive layer formed on it, and dried to obtain the present electrophotographic sensitive body.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor using a specific azo pigment.

[Prior art]

Conventional photoreceptors having a layer containing an organic pigment on a conductive layer include: (1) A method in which a pigment is dispersed in an insulating binder on a conductive layer as disclosed in Japanese Patent Publication No. 52-1667 (Electrophotography Grate). (11) JP-A-47-3
Publication No. 0328 (Electronic Photography Great), JP-A-47-1
8545 (11L photographic imaging method) or the material and an insulating binder (
A layer in which a pigment is dispersed in a charge transport medium (the binder itself may be a charge transport material) is provided on a conductive layer;
((GV, consisting of a conductive layer, a charge generation layer containing an organic pigment, and a charge transport layer as disclosed in JP-A-49-105537 (electrophotographic plate))
There are also those in which an organic pigment is added to a charge transfer complex as disclosed in Japanese Patent Application No. 1648 (photoconductive member), and (■) others.

Many pigments have been proposed for use in these photoreceptors, such as phthalocyanine pigments, polycyclic quinone pigments, azo pigments, and quinacridone pigments, but so far very few have been put into practical use. be.

The reason is that the organic photoconductive pigment is inorganic 5esCd.
This is because it is inferior in terms of sensitivity and durability compared to S%ZnO and the like.

On the other hand, inorganic photoreceptors also have problems, and Se-based photoreceptors have
Crystallization easily progresses due to factors such as temperature, humidity, dust, fingerprints, etc., and especially when the ambient temperature of the photoreceptor exceeds around 40 degrees Celsius, crystallization becomes noticeable, resulting in drawbacks such as decreased charging performance and white spots on the image. . Although the lifespan of 3e photoreceptors is said to be approximately 30,000 to 50,000 copies, because the environment varies depending on the region and location where the copier is installed, some photoreceptors may not be able to complete the lifespan mentioned above. The current situation is that this is occurring frequently.

In the case of a CdS photoconductor coated with an insulating layer, the lifespan is comparable to that of a Se-based photoconductor, but it is extremely difficult to overcome the poor moisture resistance caused by CdS, and it is necessary to prevent the photoconductor from absorbing moisture. The current situation is that supplementary means such as heaters are required.

In the case of ZnOi photoreceptors, they are sensitized with dyes such as rose bengal, so there are problems such as deterioration due to energization due to corona charging and the color of the dye's light, and the current lifespan of the photoreceptor is approximately 1,000 copies. has been done.

The sensitivity of conventional photoreceptors is 15% for unsensitized Se-based photoreceptors when expressed at half-attenuation exposure M', (E1/2).
Around tux fist sec, 4 to 8 tux・S with sensitization
CdS-based photoreceptors have a sensitivity comparable to that of sensitized Se, and ZnO-based photoreceptors have a sensitivity of 7 to 12 tu.
It is about xIIIec.

As for the sensitivity of a practical photoreceptor, the E,/2 value is desirably 20 tux-sec or less for ppc copying machines, and more desirably 15 tux-aec or less for ppc copying machines with high copying speeds. However, depending on the application, it may be possible to use it even if the sensitivity is less than the above-mentioned sensitivity.

[Purpose of the invention]

As a result of intensive research to overcome the drawbacks of conventional inorganic photoreceptors and to improve the drawbacks of organic electrophotographic photoreceptors that have been proposed so far, the present inventors have found that the following general formula [ 1)
Contains an azo pigment (hereinafter referred to as the azo pigment used in the present invention) having at least one type of 8, or two types of 8, or tl-J: 3 combined with a cazolar residue represented by The electrophotographic A photoreceptor with a photosensitive layer has high sensitivity and high durability for practical use, and also has improved heat resistance (Se crystallization) and moisture resistance, which have been problems with inorganic photoreceptors. The problem of gender, photochromicity, etc. has been determined.
1. It was discovered that this can be used as a child photographic photoreceptor, and the present invention was achieved.

General formula [■] ゝX' In the formula, R1 is a hydrogen atom, an optionally substituted alkyl group,
(For example, methyl group, ethyl group, propyl group, 18o-
propyl group, butyl group, t-butyl group, hensyl group, phenethyl group, chlorobenzyl group, dichlorobenzyl group,
Methylpennol group, ethylbenzyl group, methoxybennol group, 2-methoxyethyl group, 3-methoxypropyl group, 2-chloroethyl group, 3-chloropropyl tk, 2
- chloroethyl group, 3-chloropropyl group, 2-hydroxyethyl group, etc.), an optionally left aryl group (e.g. phenyl group, tolyl group, xylyl group, biphenyl group, chlorophenyl group, dichlorophenyl group, trichlorophenyl group, nitrophenyl group, cyanophenyl group, methoxyphenyl group, α-naphthyl group, β-naphthyl group, etc.), or an optionally substituted heterocyclic group (for example, pyridyl group, N-methyl-carbazolyl group, N-
ethyl-carbazolyl group, etc.), and R2 is an optionally substituted aryl group (for example, the group shown in R1), or an optionally substituted heterocyclic group (for example, the heterocyclic group exemplified for R4) represents.

Moreover, X represents a residue that is condensed with a benzene ring to form a naphthalene ring, an anthracene ring, a carbazole ring, a dibenzofuran ring, or a benzcarbazole ring.

1 ri:' //iu /Z1.1 4il! Among the azo pigments used in the present invention, particularly preferred are bisazo pigments or trisazo pigments represented by the following general formula (11). 〇 General formula (n) In the formula, P represents 2 or 3. and R1# R2 and X have the meanings given above. Mapζ, A Id, is a P-valent group, (a) a hydrocarbon group having at least one benzene ring, (b) a nitrogen-containing hydrocarbon group having at least two benzene rings, and (C) at least two Represents any one hydrocarbon group having a benzene ring and at least one heterocycle.

The benzene ring in (,) and (b) above is another one
The benzene ring in (C) may be fused with one or more benzene rings to form a fused ring, and the benzene ring in (C) may be fused with one or more other benzene rings or heterocycles to form a fused ring.

The hydrocarbon group (&), the nitrogen-containing hydrocarbon group (b), and the hydrocarbon group (c) may be any suitable atom, such as an oxygen atom, a halogen atom (chlorine atom, bromine atom, or iodine atom) or an organic atom. Residues, such as alkyl groups (methyl, ethyl, propyl, 1so-propyl, butyl, t-butyl, etc.), alkoxy groups (methoxy, ethoxy, zoropoxy, butoxy, etc.), dialkylamino groups (dimethylamine group, diethylamino group, dipropylamino group, dibutylamino group, nopenzolylamino group, etc.), diarylamino group (diphenylamino group, ditolylamino group, diarylamino group, etc.), acylamino group (acetylamino group, ) 0 lopionylamino group group, butyrylamino group, benzoylamino group, trioylamino group, etc.), nitro group, or hydroxy group.

To explain more specifically, specific examples of the above (&), (b) and (c) are as follows.

As “times”, etc. can be mentioned.

In the formula, R represents a hydrogen atom or a cyano group.

R4 represents a hydrogen atom or an alkoxy group (methoxy group, ethoxy group, zolopoxy group, butoxy group, etc.). R
5 and R6 are a hydrogen atom, a rhodane atom (chlorine atom, bromine atom, iodine atom), an alkyl group (methyl group, ethyl group, propyl group, lll0-zorobyl group, butyl group,
t-butyl group, etc.), alkoxy groups (methoxy group, ethoxy group, propoxy group, butoxy group, etc.) -! or a nitro group. Also, R5 and R6 are the same as those in Part 1. The same groups may be present at mutually symmetrical positions.1. The groups may be different from each other except when both groups are hydrogen atoms.

(For example, bl is etc. can be mentioned.

2H5 (4) 7 Ra R12R13 (7) R14R15 Child replaced.

etc. can be mentioned.

R7 and R8 are a hydrogen atom, a lower alkyl group (e.g., methyl group, ethyl group, propyl group, 1so-zorobyl group, butyl group, t-butyl group, etc.), a thin halodane atom (e.g., (bromine atom, iodine atom, etc.).

2 represents an oxygen atom, a sulfur atom, or) N-R16.

R16 represents a hydrogen atom or a lower alkyl group (eg, methyl group, ethyl group, propyl/J, jso-propyl group, butyl group, t-butyl group, etc.). R2 is a hydrogen atom, a halokene atom (chlorine atom, bromine atom, iodine atom), or a lower alkyl group (15'l);
1, methyl group, ethyl group, propyl group, 15o-propyl group, butyl group, t-butyl group, etc.)
111 is a hydrogen atom, a halogen atom (for example, a salt 1jjj
bromine atom, iodine atom, etc.), lower alkyl groups (e.g., methyl group, ethyl group, 20-butyl group, 1so-zorobyl group, butyl group, 1-butyl group, etc.), alkoxy groups (e.g., methoxy group, ethoxy group, propoquine group,
butoxy group, etc.), hydroxyl group, nitro group, noalkylamino group (e.g., trimethylamine group, diethylamine group, dipropylamino group, etc.) or acylamino group (e.g., acetylamino group, propionylamino group,
butyrylamino group, benzoylamino group, trioylamino group, etc.). , n is O-Sat or 1,
m is a 1ζ number from 1 to 4.

Substituents or U atoms include halogen atoms (for example, chlorine atoms, bromine atoms, iodine atoms, etc.), alkyl groups ([+
For example, methyl group, ethyl group, propyl group 1iso-
Examples include zolopyl group, butyl group, t-butyl group, etc.), alkoxy groups (eg, methoxy group, ethoxy group, propoxy group, butoxy group, etc.), cyano group, and the like. R12 and R13 are an ice water atom, a halogen atom (chlorine atom, bromine atom, iodine atom, etc.) or a lower alkyl group (methyl group, ethyl group, propyl group, 1so-propyl group, butyl group, t-butyl group, etc.) shows.

R14 and R15 are a hydrogen atom, a halogen atom (chlorine atom, bromine atom, iodine atom, etc.), a lower alkyl group (methyl group, ethyl group, propyl Jk, 1so-propyl group, butyl group, t-butyl group, etc.), Alkoxy group (methoxy group, ethoxy group, propoxy group, butoxy group, etc.)
, nitro group or acylamino group (acetylamino group,
propionylamino group, butyrylamino group, benzoylamino group, trioylamino group, etc.).

The azo pigment represented by the general formula (n) is a starting material compound, an amine represented by the general formula A + NH2) n (wherein n represents 2 or 3, and A represents the same meaning as above). Tetrazotization or hexazation is carried out by a conventional method, and then coupling is performed with the cazolar residue of the general formula (1) in the presence of an alkali, or the tetrazonium salt of the amine is converted to boron 7. Once isolated in the form of a zinc chloride salt or a zinc chloride salt, it is easily coupled with the above-mentioned zinc chloride salt in the presence of an alkali in a suitable solvent (for example, N, N-methyland, or zinc chloride). can be manufactured.

The electrophotographic photoreceptor of the present invention is azo f1i used in the present invention.
It is characterized by having a photosensitive layer containing $1, and is suitable for use with any of the types (1) to (V) mentioned above.
11a It can also be applied to light bodies, but is it caused by light absorption of azo pigments? In order to increase the transport efficiency of the load carrier, it is desirable to use it as a photoreceptor of type (ii) or (iiiL 4v).

A photoreceptor of the (iii) type is preferable in order to take advantage of the characteristics of the pigment.

Therefore, this type of 1.14-photoreceptor A photoreceptor will be described in detail below.

) As the layer structure, a conductive layer, a charge generation layer, and a charge transport layer are essential, and the charge generation layer may be either the upper part or the lower part of the charge transport layer. In an electrophotographic photoreceptor of the type that is used repeatedly, it is preferable to laminate a conductive I- layer, a charge generation layer, and a charge transport layer in this order mainly from the viewpoint of physical strength and, in some cases, from the viewpoint of chargeability. An adhesive layer may be provided as necessary for the purpose of improving the adhesion between the conductive layer and the charge generation resistor.

As the conductive layer, a metal foil made from a metal plate such as aluminum, a glass film on which a metal such as aluminum is vapor-deposited, an aluminum foil laminated with paper, paper treated with conductivity, etc. are used.

The adhesive layer material is casein, 11? IflJ fats such as ribinyl alcohol, aqueous, triethylene, and nitrocellulose are effective. The thickness of the 1v adhesion layer is 0.1~
A suitable value is 5μ, preferably 05 to 3μ.

After the azo pigment used in the present invention is made into fine particles on the conductive layer or the adhesion layer of 1 m on the conductive layer, the azo pigment used in the present invention is dispersed without a binder or in an appropriate binder solution if necessary, and this is applied and dried. Provided.

In dispersing the azo pigment, known methods such as beer mills and attritors can be used, and the pigment particles are preferably 5 μm or less, preferably 2 μm or less, and suitably 0.5 μm or less.

Are azo pigments amine-based such as ethylenecyamine? It can also be applied by dissolving it in agent H. Conventional methods such as blade, Meyer per, spray dipping, etc. are used for application.

The thickness of the charge generation layer is 5μ or less, preferably 0.01 to 1μ
is desirable. When a binder is used in the charge generation layer, a large amount of binder will affect the sensitivity, so the proportion of the binder in the charge generation layer is preferably 80 qb or less, preferably 40 qb or less.

Binder used in history include polyvinyl butyral, polyvinyl acetate, and 7j? Realester, polycarbonate, phenoxy resin, acrylic resin, noryacrylamide, polyamide, polyvinylpyridine resin, cellulose resin, urethane resin, engineering month? Various resins such as xybrJ fat, casein, and polyvinyl alcohol are used.

A charge transport layer is provided on the charge generation layer thus provided.

If the charge transport material does not have film-forming ability, a solution prepared by dissolving a binder in a suitable organic solvent is applied by a conventional method and dried to form a charge transport layer.

Charge transport materials include electron transport materials and hole transport materials.

Examples of electron transporting substances include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane,
2.4.7-) Rinitro 9-fluorenone, 2,4,
5.7-titranitrofluorenone, 2.4.7-dolinitro9-dicyanomethylenefluorenone, 2,4,
There are screen attracting substances such as 5.7-titranitroxanthone and 2.4.8-trinidrothioxanthone, and polymerized products of these electron-attracting substances.

Suitable hole-transporting substances include, for example, hydrazones, pyrazolines (1) 1-phenyl-3-(4-N,N-diethylaminostyryl)-5-(4-N,N-diethylaminophenyl)pyrazoline ( 2) 1-phenyl-3-(4-N,N-dibenzylstyryl)-5-(4-N,N-diethylaminophenyl)pyrazoline (3)1-phenyl-3-(4-N,N-dibenzylstyryl) benzylstyryl) -5-4-(N,N-dibenzylaminophenyl)pyrazoline (4) 1-(pyridyl (2) ] -3-(4-N,
N-diethylaminostyryl) -5-(4-N,N
-diethylaminophenyl)pyrazoline (5) 1-(quinolyl-(2) ) -3-(4-N,
N-diethylaminostyryl) -5-(4-N,N
-diethylaminophenyl)pyrazoline (6) 1-(quinolyl-4) -a -(4-N,N
-diethylaminostyryl) -5-(4-N,N -
diethylaminophenyl)pyrazoline (7) 1-(3-methoxy-pyridyl (2) ]-3-
(4-N,N-diethylaminostyryl)-5-(4-
N,N-diethylaminophenyl)pyrazoline (8) 1-(levidyl-(2) ) -3-(4-N,
N-diethylaminostyryl) -5-(4-N,N
-diethylaminophenyl)pyrazoline (9) 1-phenyl-3-(4-N,N-diethylaminostyryl)-4-methyl-5-(4-N,N-diethylaminophenyl)pyrazoline (IQ 1-phenyl-
3-(α-Methyl-4-N,N-diethylaminostyryl)-5-(4-N,N-diethylaminophenyl)pyrazoline CI])ir:pyridyl(3))-3-(
4-N,N-diethylaminostyryl) -5-(4-
N,N-diethylaminophenyl)pyrazoline 021-phenyl-3-(α-benzyl-4-N,N-
diethylaminostyryl)-5-(4-N,N-diethylaminophenyl)bilacyrindiarylalkane (1) 1.1-bis(4-N,N-・trimethylaminophenyl)propane (2> 1.1- Bis(4-N,N-diethylaminophenyl)zolonophane (3) 1.1-Bis(4-N,N-diethylamino-
2-methylphenyl) fronoC (4) 1.1-bis(4-N,N-diethylamino-
2-methoxyphenyl)propane (5)' 1.1-bis(4-N,N-dibenzylamino-2-meth)oxyphenyl)-2-methylpropane (6
) 1.1-bis(4-N,N-diethylamine-2-
methylphenyl)-2-phenylzolono R7(7) x
,:r-bis(4-N,N-diethylamine-2-methylphenyl)butane (+3) 1.1-bis(4-N,N-dibenzylamino-2-methphenyl)-1-cyclohexyl Methane (9) 1,1-bis(4-N,N-trimethylaminophenyl)pentane CIt) 1,1-bis(4-N,N-dibenzylaminophenyl)normalbutane triarylalkanes (1) 1.1-bis(4-N,N-trimethylaminophenyl)-1-phenylmethane (2) i,i-bis(4-N,N-diethylaminophenyl)-1-phenylmethane (3) 1.1-bis(4-N,N-diethylamino-
2-methylphenyl)-1-phenylmethane (4) 1
．． 1-bis(4-N,N--diethylamino-2-ethylphenyl)-2-phenylethane (5) 1.1-
Bis(4-N,N-diethylamine-2-methylphenyl)-3-phenylpropane (6) 1.1-Bis(4
-N,N-diethylamino-2,5-dimethoxyphenyl)-3-phenylzolonoxadiazoles (1) 2.5-bis(4-N,N-dimethoxyphenyl) -1,3,4 -Oxadiazole (2) 2
．． 5-bis(4-N,N-diethylaminophenyl)
-1,3,4-oxadiazole (3) 2,5-bis(4-N,N-diglobylaminophenyl) -1,3
,4-oxadiazole (4) 2.5-bis(4-N
, N-dibenzylaminophenyl) -1,3,4-oxadiazole (5) 2-methyl-5-(3-carbazolyl)-1,3,4-oxadiazole (6) 2-ethyl-5 -(3-carbazolyl)-1,3
,4-oxadiazole (7) 2-ethyl-5-(9-ethyl-3-carbazole) -1,3,4-oxadiazole (8) 2-N
, N-diethylamino-5-(9-ethyl-3-carbazole)-1,3,4-oxanoazole (9) 2-styryl-5-(3-carbazolyl)-1,
3,4-Oxadiazoleanthracenes (1) 9-styrylaminostyryl (2) 9- (4-N, N-dimethylaminostyryl) anthracene (3) 9- (4-N, N-diethylaminostyryl) Anthracene (4) 9- (4-N, N-dibenzylaminostyryl) anthracene (5) 4-promo 9- (4-N, N-diethylaminostyryl) anthracene (6) α-(9-anthryl)-β -(3-carbazolyl)ethylene (7) α-(9-anthryl)-β-(9-ethyl-
3-carbazolyl) ethylene oxazole (1) 2- (4-N, N-diethylaminophenyl)-4-(4-N, N-dimethylaminophenyl)-5
-(2-chlorophenyl)oxazole (2) 2-
(4-N,N-diethylaminophenyl)-5-phenyloxazole (3) 4-(4-N,N-dimethylaminophenyl)-5-(2-10lophenyl)oxazole (4)
2-(4-N,N-dimethylaminophenyl)-4,
5-Diphenyloxazole (5) 2-(4-N,N-dimethylaminophenyl)-4-(4-N,N-diethylaminophenyl)-5
-(2-10lophenyl)oxazole (6) 2.5
-di(2-chlorophenyl)-4-(4-N,N-diethylaminophenyl)oxazole and the like. Others: pyrene, N-ethylcarbazole, triphenylamine, poly-N-vinylcarbazole, halodanated poly-N-vinypolyrubazole, polyvinylpyrene, polyvinylanthracene, 4
Livinyl ataridine, yJ'! j -9-vinylphenylanthracene, pyrene-formaldehyde resin, ethylcarbazole formaldehyde resin, etc. can also be used.

The charge transport material is not limited to those described herein, and when used, one type of charge transport material or a mixture of two or more types of charge transport materials can be used. however,
When an electron-transporting substance and a hole-transporting substance are mixed,
Charge transfer absorption may occur in the visible region, and even when exposed to light, light may not reach the charge generation layer located below the charge transport layer. The thickness of the charge transport layer is 5 to 30 microns, preferably 8 to 20 microns.

As a binder, acrylic resin, I-restyrene, I-
Reester, polycarbinate, etc. can be used. As the binder for the low-molecular hole-transporting substance, a hole-transporting polymer such as the aforementioned poly-N-vinylcarbazole can be used as the binder. On the other hand, USP 412211 is used as a binder for low-molecular electron transporting substances.
Polymers of electron transporting monomers such as those shown in 3 can be used.

When using a photoreceptor in which a conductive layer, a charge generation layer, and a charge transport layer are laminated in this order, and the charge transport material is an electron transport material, it is necessary to positively charge the surface of the charge transport layer, and when exposed to light after charging, In the exposed area, electrons generated in the charge generation layer are injected into the charge transport layer, and then reach the surface to neutralize the positive charges, resulting in attenuation of the surface potential and an electrostatic contrast between the exposed area and the unexposed area. A visible image can be obtained by developing the electrostatic latent image thus formed with a negatively charged toner. This can be directly fixed, or the toner image can be transferred to paper or plastic film and then developed and fixed.

Alternatively, a method may be used in which the electrostatic latent image on the photoreceptor is transferred onto an insulating layer of transfer paper, then developed and fixed. Types of developer and development method,
The fixing method is not limited to a specific method and may be any known method.

On the other hand, when the charge transport material is a hole transport material, the surface of the charge transport layer must be negatively charged, and when image exposure is performed after charging, holes generated in the charge generation layer are injected into the charge transport layer in the exposed area. After that, the negative charges that have reached the surface are neutralized, the surface potential is attenuated, and an electrostatic contrast is created between the surface potential and the unexposed area. During development, it is necessary to use a positively charged toner, contrary to the case where an electron transport material is used.For medium type photoreceptors, the present invention is applied to an insulating binder solution such as that used in the charge transport layer of GiD Tyg photoreceptors. It is obtained by adding the azo pigment used in , dispersing it, coating it on the conductive layer and drying it.

The (11) type photoreceptor is prepared by dissolving the charge transport material of the (il) type photoreceptor and an insulating binder such as that used in the charge transport layer in a suitable solvent, and then adding the azo pigment used in the present invention. After dispersion, it is obtained by coating and drying on a conductive layer.

The 4-function type photoreceptor forms a charge transfer complex when the electron transport material and hole transport material described in G11) type photoreceptor are combined, so the azo pigment used in the present invention is added to the solution of this charge transfer complex. After addition and dispersion, it is obtained by coating and drying on a conductive support.

The azo pigment used in any of the photoreceptors contains at least one type of pigment selected from the azo pigments used in the present invention, and if necessary, pigments with different light absorptions may be used in combination to increase the sensitivity of the photoreceptor. For the purpose of obtaining a panchromatic photoreceptor, it is also possible to use a combination of two or more types of azo pigments used in the present invention, or to use them in combination with a charge generating material selected from known dyes and pigments.

The electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines, but also in a wide range of electrophotographic applications such as laser printers and CRT printers.

Next, the azo pigment used in the present invention will be specifically explained using synthesis examples.

2.5-di(p-aminophenyl)-1,3,4-oxadiazole 4.52 g (o, o176 mol), water 5
A dispersion of 5 ml and 10.0 ml of concentrated hydrochloric acid was added to 4
After cooling to ℃, add 3.60J of sodium nitrite. (0,0
376 mol) of water at 9 mA! was added dropwise over a period of 15 minutes, and stirred for 30 minutes while maintaining the temperature of the liquid at 3 to 5°C. Then, activated carbon was added and filtered. mol) was added. The precipitated crystals were collected, washed with cold water, and then dried under reduced pressure to obtain tetrazonium salt 5.6I. Yield 72.2 inches.

Next, 5.0 g (0,011
5 mol) and 7.4 g (0,0243 mol) of cazoler with the structural formula were dissolved in 300 ml of dimethylformamide (DMF), and 10 ml of pyridine was added dropwise over 5 minutes while keeping the liquid temperature at 6 to 8°C. After stirring for 2 hours, the mixture was left at room temperature overnight.

The reaction solution was filtered, DMF, and tetrahydrofuran (T
8.4. ! I got i+. Yield 82.6%. Decomposition point: 300°C or higher, molecular formula: C52H! 18N1005 Calculated value (%') Analytical value (%) C70,7370,86 H4,344,3O N 15.87 15.65 Although the method for synthesizing only one type of pigment has been described above, other azo Pigments are also synthesized in a similar manner.

Next, examples of the present invention will be shown.

Example 1 An aqueous solution of I-rivinyl alcohol was applied and dried on an aluminum plate with a thickness of 100μ, and the coating amount was 0.8. An adhesive layer having a thickness of 9/m'' was formed.

Next, the A1 pigment 5I and polyester resin (1?Reester Adhesion 49000 manufactured by DuPont, solid content 2
0%) 10,9, tetrahydrofuran (80 ml) was applied onto the adhesive layer with a dispersion diameter above, and the coating amount after drying was 0.20,9.
The area was 7m2.

Next, 5 g of K,4-N,N-diethylaminobenzaldehyde-N,N-nophenylhydrazone and 5 g of polymethyl methacrylate resin (number average molecular weight 100,000) were dissolved in tetrahydrone fluorine and coated on the charge generation layer. The coating amount after drying was 1'09/m''.

The electrophotographic photoreceptor produced in this way was manufactured by Kawaguchi Electric Co., Ltd.
The sample was statically charged with corona at 95 kV using an electrostatic copying paper tester Model SP-428, held in a dark place for 10 seconds, and then exposed to light at an illuminance of 5 Lux to examine the charging characteristics.

The initial potential is V. (V), potential holding rate for 10 seconds in the dark is vk (%), half-attenuation exposure is EV2 (tux-see
), which shows the charging characteristics of this photoreceptor.

Vo; e530V+vk+, 93% + Ey,
: 6.8 tux-sec Examples 2 to 24 In the azo pigment used in the present invention, P of general formula (II)
, A, and the cazolar component are each prepared by dissolving 5 g of azo pigment shown in Part 1 below and 2 g of butyral resin (degree of butyralization: 63 mol l) in 5 ml of ethanol. - After dispersing with Lumil, it was coated on the adhesive layer with Meyer Tsukku to form a charge generation layer having a coating weight of 0.211/m'' after drying.

Next, the same charge transport layer solution used in Example 1 was applied using a paper applicator, and the film thickness after drying was 10 g.
/m2. The charge measurement of the photoreceptor was carried out in the same manner as in Example 1.

Table 1 shows the structure of the pigment used, and Table 2 shows the charging characteristics.

Table 2 Charging characteristics Example 25 5 g of 2.4.7-trinitrofluorenone and poly-4,4'-dioxydiphenyl-2,2-casenate (viscosity average molecular weight 30
,000)5. ! Dissolve i' in 70 ml of THF,
The coating amount after coating and drying is 12. j9/m''. Charge measurement was carried out in the same manner as in Example 1, and the characteristic values were as follows. However, the charge polarity was set to ■.

v0■: 520V vk; 90chi E17: 19.3 tuc-sec Example 26 An ammonia aqueous solution of casein was coated on a 100μ thick aluminum plate and dried, and the coating amount was 1. An adhesive layer of "Of//m" was formed.

Then, 2-(4-N,N-diethylaminophenyl)
-4-(4-N,N-dimethylaminophenyl)-5-
A6 pigment 1 used in Example 6 was added to a solution in which 5 g of (2-chlorophenyl) and 5.9 g of poly-N-vinylcarbazole (number average molecular weight 30 g) were dissolved in 0 d of tetrahydrone.
．． 0 g was added and dried by coating on the adhesive layer with a dispersion diameter of 12 fl/m''.

The photoreceptor thus prepared was subjected to charge measurement in the same manner as in Example 1, and the measured values were as follows. However, the charging polarity was set to ■.

■o; ■530V vk; 91"'14.: 21.2 tux-sec Example 27 1-phenyl-3(4-N,N-diethylaminostyryl) -5-(4-N,N-diethylaminophenyl )
Hirazoline 5 g Toho! J-2,2-f-9bis(4-phenyl inphthalic acid/terephthalic acid ester)
(Isophthalic acid terephthalic acid molar ratio 1:1)5. li'
was dissolved in 70rrLl of tetrahydrofuran, 1g of the boiled pigment used in Example 1 was added, and after dispersion, it was applied and dried on the adhesive layer used in Example 1 to give a coating amount of 12fl.
/m”.The photoreceptor thus prepared was used in Example 1.
Charge measurement was carried out in the same manner as above, and the measured values were as follows. However, the charging polarity was set to ■.

■o; ■510v V) (: 89chi El/,: 17.51ux・mec Examples 28 to 32 5g of pigment A10 used in Example 10 and 2g of butyral resin (degree of butyralization 63mol) were mixed with 95% ethanol.
After dispersing with the liquid dissolved in m/, it was applied to the aluminum surface of the aluminum vapor-deposited mylar film, and the coating amount after drying was 0.
．． 2, jil 7 m'', and then a solution prepared by dissolving the charge transporting material 5I shown in Table 3 and phenoxy resin (Bakelite PKHH manufactured by UCC Co., Ltd.) in THF 70- was applied to the charge generation layer, dried, and coated. A charge transport layer having an amount of 11 fi/m'' was formed.

The photoreceptor thus prepared was subjected to charge measurement in the same manner as in Example 1, and its characteristics are shown in Table 4.

Table 3 Charge Transport Materials Table 4 Charging Measurement [Effects of the Invention] The electrophotographic photoreceptor of the present invention has high sensitivity that surpasses even high-sensitivity inorganic photoreceptors such as conventional Se photoreceptors. In addition to having extremely excellent properties and high durability, the heat resistance, moisture resistance, and light chromaticity, which were known to be shortcomings of inorganic photoreceptors, have naturally been improved. It has extremely excellent properties as a photographic photoreceptor.

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor having a photosensitive layer, the photosensitive layer containing an azo pigment having at least one azo group bonded to a coupler residue represented by the following general formula [I] in the molecule. An electrophotographic photoreceptor characterized by: General formula (I) In addition, X represents a residue that is condensed with a benzene ring to form a naphthalene ring, anthracene ring, carbazole ring, dibenzofuran ring, or benzcar-guzol ring.)