JPS61246754A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To facilitate manufacture of an electrophotographic sensitive body and to lower cost by forming an electrostatic charge generating layer contg. a specified disazo pigment on a conductive substrate. CONSTITUTION:The charge generating layer contains the disazo compd. represented by formula I in which A is a coupler residue, such as a group of phenol, naphthol, OH-having hetero ring, amino-having aromatic or hetero ring, aminonaphthol, aliphatic or aromatic phenolic ketone, exdemplified by formula II. A sharp transferred image can be obtained by laminating on the condutive substrate the charge generating layer contg. thid disazo pigment and a charge transfer layer on this layer to form the electrophotographic sensitive body.

Description

[Detailed Description of the Invention] The present invention relates to a photoreceptor for electrophotography, and more specifically,
The present invention relates to an electrophotographic photoreceptor provided with a photosensitive layer containing a disazo pigment as a substance that generates charge carriers when irradiated with light (hereinafter referred to as a "charge-generating substance").

As photoconductors for electrophotography, inorganic photoconductors include those using selenium and its alloys, or photoconductors with dye-sensitized zinc oxide dispersed in a binder resin, and organic photoconductors. A typical known example is one using a charge transfer complex of 2°4,7-dolinitro-9-fluorenone (hereinafter referred to as rTNFJ) and poly-N-vinylcarbazole (hereinafter referred to as rPVKJ).

However, while these photoreceptors have many advantages, they also have various disadvantages.

For example, the currently widely used selenium photoreceptor has difficult manufacturing conditions and high manufacturing costs, is difficult to process into a belt due to its lack of flexibility, and is sensitive to heat and mechanical shock. Therefore, care must be taken when handling. Zinc oxide photoreceptors are low in cost because they can be manufactured by applying inexpensive zinc oxide to a support, but they generally have low sensitivity, poor surface smoothness, and hardness.

It has mechanical drawbacks such as tensile strength and abrasion resistance, and there are many problems with durability as a photoreceptor for plain paper copiers that are normally used repeatedly. The photoreceptor used had low sensitivity and was unsuitable as a photoreceptor for high-speed copying machines.

In recent years, extensive research has been carried out to eliminate the drawbacks of these photoreceptors, and in particular, various organic photoreceptors have been proposed. Among them, a laminated photoreceptor in which a thin film of an organic pigment is formed on a conductive support (charge generation layer), and a layer mainly composed of a charge transport substance (charge transport layer) is formed on top of this, is a layered photoreceptor that is different from conventional organic pigments. Compared to photoconductors, photoconductors are attracting attention as photoconductors for plain paper copying machines because of their high sensitivity and stable charging properties, and some of them are in practical use.

As this kind of conventional laminated photoreceptor.

(1) A thin layer of a perylene derivative vacuum-deposited as a charge generation layer and an oxadiazole derivative used as a charge transport layer (see USP 3871882) (2) An organic amine of chlordiane blue as a charge generation layer. A thin layer formed by applying a solution is used, and a hydrazone compound is used as the charge transport layer (Japanese Patent Publication No. 55-4238
(see Publication No. 0) are known. .

However, it is true that conventional laminated photoreceptors of this type have many advantages, but also have various drawbacks. In other words, this is a first-order defect.

The photoreceptor using the perylene derivative and oxadiazole derivative shown in (1) has a charge generation layer formed by vacuum evaporation, which increases the manufacturing cost.

The photoreceptor using chlordiane blue and a hydrazone compound as shown in (2) requires the use of an organic amine (e.g. ethylenediamine), which is generally difficult to handle, as a coating solvent for forming the charge generation layer. There are many drawbacks to the above.

Furthermore, it is an object of the present invention to provide a photoreceptor which overcomes the above-mentioned conventional drawbacks.

1-1 The electrophotographic photoreceptor of the present invention is characterized in that a photosensitive layer containing a disazo pigment represented by the following general formula (1) as a charge generating substance is provided on a conductive support. It is.

A-N=N-e-N-@-N=N-A (In the formula, A represents a coupler residue) Incidentally, the present inventor took into account the drawbacks of the conventional art.

As a result of extensive research aimed at developing an electrophotographic photoreceptor that is easy to manufacture, has high sensitivity, and is sensitive to short wavelengths (that is, has excellent image reproducibility for red originals), It has been discovered that the above object can be achieved by using a specific disazo compound represented by the general formula (R) as a charge generating substance, and the present invention has been completed based on this finding.

Couplers in the general formula (2) include aromatic hydrocarbon compounds having a hydroxyl group such as phenols and naphthols, heterocyclic compounds having a hydroxyl group, aromatic hydrocarbon compounds having an amino group, and heterocyclic compounds having an amino group. Formula compounds, aromatic hydrocarbon compounds and heterocyclic compounds having a hydroxyl group and an amino group such as aminonaphthols, compounds having an aliphatic or aromatic enolic ketone group (compounds having an active methylene group), etc. are used. Preferably, the coupler residue A has the following general formula (U), (III), (IV), (V), (VI
), (■), (■), (IX), (X), (XI)
, (Kari).

'Z''Z' [in the above formulas (II), (m), (IV) and (V),
X# Yzy Zt m and n each represent the following.

(R□ and R2 represent hydrogen or a substituted or unsubstituted alkyl group, and R1 represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted 7-aryl group.) Yl: hydrogen, halogen, substituted or unsubstituted an alkyl group, a substituted or unsubstituted alkoxy group, a carboxy group, a sulfo group, a substituted or unsubstituted sulfamoyl group, or 100N-Y.

(R4 represents hydrogen, an alkyl group or a substituent thereof, a phenyl group or a substituent thereof, Yyo is a hydrocarbon ring group or a substituent thereof, a heterocyclic group or a substituent thereof.

Pa1 Hydrocyclic group or a substituent thereof, a heterocyclic group or a substituent thereof, a styryl group or a substituent thereof, R6 represents hydrogen, an alkyl group, a phenyl group or a substituent thereof, or R1 and R6 are bonded to them. 2: Hydrocarbon ring or its substituted product or heterocycle or its substituted product n: An integer of 1 or 2 m: An integer of 1 or 2] [Formula In (Vl) and (■), R7 represents a substituted or unsubstituted hydrocarbon group, or is the same as above. ] Ar.

[In the formula, R represents an alkyl group, a carbamoyl group, a carboxyl group, or an ester thereof, and Ar1 represents a hydrocarbon ring group or a substituent thereof, or is the same as above. ] [In the above formulas (W) and (X), R1 represents hydrogen or a substituted or unsubstituted hydrocarbon group, and Arc represents a hydrocarbon ring group or a substituted product thereof.] The above general formula (II), ( Examples of the hydrocarbon ring in m), (IV) or (V) 2 include a benzene ring and a naphthalene ring, and examples of the heterocycle include an indole ring, a carbazole ring, and a benzolane ring. Examples of substituents on the ring of Z include halogen atoms such as chlorine atoms and bromine atoms, and alkoxy groups.

Examples of the hydrocarbon ring group in Y2 or R1 include phenyl group, naphthyl group, anthryl group, pyrenyl group, etc.
Examples of the heterocyclic group include a pyridyl group, a chenyl group, a furyl group, an indolyl group, a benzofuranyl group, a carbazolyl group, and a dibenzofuranyl group.
Examples of the ring formed by combining 8 and R6 include a fluorene ring.

Substituents on the hydrocarbon ring group or heterocyclic group of Y2 or R5 or the ring formed by R5 and R6 include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, methoxy group, ethoxy group, propoxy groups, alkoxy groups such as butoxy groups, halogen atoms such as chlorine atoms and bromine atoms, dialkylamino groups such as dimethylamino groups and diethylamino groups, dialkyl groups such as dibenzylamino groups, amino groups, and halomethyl groups such as trifluoromethyl groups. , a nitro group, a cyano group, a carboxyl group or its ester, a hydroxyl group, and a sulfonic acid group such as -SO and Na.

Examples of substituents for the phenyl group of R4 include halogen atoms such as chlorine atoms and bromine atoms.

Representative examples of the hydrocarbon group in R7 or R are:
Examples include alkyl groups such as methyl, ethyl, propyl and butyl groups, aralkyl groups such as benzyl, teryl groups such as phenyl, and substituted products thereof.

As a substituent in the hydrocarbon group of R7 or R9,
Examples include alkyl groups such as methyl, ethyl, propyl, and butyl groups; alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy; halogen atoms such as chlorine and bromine; hydroxyl and nitro groups. .

Typical examples of the hydrocarbon ring group in Ar or Ar2 are phenyl group, naphthyl group, etc.
Substituents for these groups include alkyl groups such as methyl, ethyl, propyl, and butyl, alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy, nitro, chlorine, bromine, etc. Examples include halogen atoms, dialkylamino groups such as cyano groups, dimethylamino groups, and diethylamino groups.

Furthermore, among X, a hydroxyl group is particularly suitable.

Among the above coupler residues, preferred is the general formula (
III), (VI), (■), (■), (IK) and (X), and among these, it is preferable that X in the general formula is a hydroxyl group; A coupler residue represented by the formula [) (y 1 and Z are the same as above) is preferred, and a coupler residue represented by the general formula (z, y, and R2 are the same as above) is more preferred.

Furthermore, among the above preferred coupler residues, general formula (XIII) or (XIV) HOCONHN=C L (Z, R, , R, and R6 are the same as above, and R1. (Examples include substituents.) Those represented by the following are suitable.

Specific examples of the disazo pigment used in the present invention as described above are shown in the following structural formula.

(Hereafter the margin) (Hereafter the margin) (Hereafter the margin) (Hereafter the margin) (Hereafter the margin) (Hereafter the margin) (Hereafter the margin) (Hereafter the margin) (Hereafter the margin) By using the disazo pigment of the present invention as described above, high-sensitivity electrophotography can be achieved. Photoreceptors can be easily manufactured.

The disazo pigment of the present invention is available as a commercial product (for example, commercially available from Tokyo Kasei Kogyo Co., Ltd.)4.
4'-Diaminodiphenylamine is diazotized to a tetrazonium salt by a conventional method, and the tetrazonium salt and the corresponding coupler are mixed in a suitable organic solvent such as N, N-
It can be easily produced by carrying out a coupling reaction with a base in dimethylformamide. As an example, a production example of the Ma74 disazo pigment is shown below, but other disazo pigments can also be easily produced according to this production example, except for changing the coupler.

Production Example of Tetrazonium Salt 18.29 g of 4,4'-diaminodiphenylamine sulfate and 7.6 g of calcium chloride were added to hydrochloric acid consisting of 228 m 11 of water and 37.5-Q of concentrated hydrochloric acid, and after thorough stirring, Cool to 0°C, then add a solution of 9.39g of sodium nitrite dissolved in 76ml of water to 0°C.
It was added dropwise over a period of 20 minutes at a temperature of . After that, after stirring at the same temperature for 30 minutes, 1 reaction solution was filtered, and this filtrate was added with 4
70ml of 2% borohydrofluoric acid was added, and the precipitated crystals were separated, washed with methanol, and dried to obtain 7g of crude bisdiazonium bistetrafluoroborate 1s, z (yield 66.7%). .

Next, this crude product was recrystallized from a 200 ml fishing rod to obtain 12.55 g (yield 51.4%) of a purified product as yellow needle crystals.

Infrared absorption spectrum (KBr disk) is 2250
The absorption band based on N2° in cm-” is 3350cga-
”, an absorption band based on NH was observed.

Diazonium Nα74: 0.99 g of the above tetrazonium salt and 2-hydroxy-3-phenylcarbamoyl ILH as a coupling component.
- 1.76 mol of benzo(a)carbazole (twice the mole of the tetrazonium salt) in cooled N.

N-dimethylformamide 150 was dissolved in Layer Q, and a solution consisting of 2 g of sodium acetate OJ and 7 mΩ of water was added dropwise thereto at a temperature of 5 to 10°C for 5 minutes, and after cooling was discontinued, the mixture was further stirred at room temperature for 3 hours. . Then, collect the formed precipitate.

N,N-dimethylformamide heated to 80°C 200
Washed three times with ml, then twice with water 200 rm Q, dried at 80°C under vacuum of 2+++ mHg,
1.90g of disazo compound of compound Na14 in Table-1
(yield 82.3%). The appearance of this disazo compound is a purple-black powder with an infrared absorption spectrum (KB
rBr method) is shown in FIG.

In the electrophotographic photoreceptor of the present invention, a disazo pigment is used as a charge-generating substance in the photosensitive layer, and typical configurations of the two photoreceptors are shown in FIGS. 1 and 2.

The photoreceptor shown in FIG. 1 has a laminated photosensitive layer 19 on a conductive support 11, consisting of a charge generation layer 15 mainly composed of a disazo pigment 13 and a charge transport layer 17 mainly composed of a charge transport substance.
1.

In the photoreceptor shown in FIG. 1, the imagewise exposed light passes through the charge transport layer and reaches the charge generation layer 15, where the disazo pigment 13 generates a charge, while the charge transport layer 17 The mechanism is such that the disazo pigment 13 generates the charge necessary for light attenuation, and the charge transport layer 17 transports the charge.

The photomaterial shown in FIG. 2 has a photosensitive layer 192 mainly composed of a disazo pigment 13, a charge transport substance, and an insulating binder on a conductive support 11.

Again, the disazo pigment 13 is a charge generating substance.

In other photoreceptors, the charge generation layer and charge transport layer may be reversed as shown in FIG.

The thickness of the photosensitive layer is as shown in FIG. 1, and the thickness of the charge generation layer 15 is preferably 0.01 to 5μ, more preferably 0.05μ.
~2μ. If the thickness is less than 0.01 μm, charge generation will not be sufficient, and if it is more than 5 μm, the residual potential will be too high for practical use.

The thickness of the charge transport layer 17 is preferably 3 to 50 microns, more preferably 5 to 20 microns. If the thickness is less than 3 μm, the amount of charge will be insufficient, and if it is more than 50 μm, the residual potential will be too high to be practical.

The charge generation layer 15 is mainly composed of a disazo pigment represented by the above general formula, and may further contain a binder, a plasticizer, and the like. Further, the proportion of the disazo pigment in the charge generation layer is preferably 30% by weight or more, more preferably 50% by weight or more.

The charge transport layer 17 is mainly composed of a charge transport substance and a binder, and may further contain a plasticizer. The proportion of charge transport material in the charge transport layer is from 10 to 95% by weight, preferably from 30 to 90% by weight. When the proportion of the charge transport substance is less than 10% by weight, almost no charge is transported, and when it is more than 95% by weight, the mechanical strength of the photoreceptor film is so poor that it cannot be put to practical use.

In the case of the photoreceptor shown in FIG. 2, the thickness of the photosensitive layer 192 is preferably 3 to 50 microns, more preferably 5 to 20 microns. Further, the proportion of the disazo pigment in the photoreceptor 192 is preferably 50% by weight or less, more preferably 20% by weight.
or less, and the proportion of the charge transport substance is preferably 10
It is 95% by weight, more preferably 30-90% by weight.

The gist of the present invention is to use a specific disazo pigment represented by the general formula (I) as a charge generating substance in an electrophotographic photoreceptor, and a conductive support,
Any conventionally known components such as charge transport materials can be used, and these will be specifically explained below.

The conductive support used in the photoreceptor of the present invention includes a metal plate made of aluminum or zinc, a plastic sheet or film made of polyester, etc., on which a conductive material such as aluminum or SnO□ is deposited, or conductive treatment. paper, etc. is used.

Binders include polyamide and polyurethane.

Examples include condensation resins such as polyester, epoxy resin, polyketone, and polycarbonate, and vinyl polymers such as polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, and polyacrylamide, but all resins that are insulating and adhesive can be used. Can be used.

Examples of plasticizers include halogenated paraffins, polychlorinated biphenyls, dimethylnaphthalene, and dibutyl phthalate. In addition, silicone oil or the like may be added to improve the surface properties of the photoreceptor.

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

As the hole transport substance, for example, the following general formulas (1) to
Examples include compounds shown in (11).

R□,.

[In the formula, R1□ represents a methyl group, an ethyl group, a 2-hydroxyethyl group, or a 2-chloroethyl group, and R12
s represents a methyl group, an ethyl group, a benzyl group, or a phenyl group, and R1□ represents hydrogen, chlorine, bromine, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, a dialkylamino group, or a nitro group. represent. ]Ar3-CH=N-
N-◎ 14s [In the formula, Ar represents a naphthalene ring, an anthracene ring, a styryl group, a substituent thereof, or a pyridine ring, a furan ring, or a thiophene ring, and R14s represents an alkyl group or a benzyl group. ] Rls.

[In the formula, Rlo represents an alkyl group, benzyl group, phenyl group, or naphthyl group, and R1° is hydrogen and has 1 to 1 carbon atoms.
3 represents an alkyl group, an alkoxy group having 1 to 3 carbon atoms, a dialkylamino group, a dialkylamino group, or a diarylamino group, n represents an integer of 1 to 4, and n represents 2
In the above cases, Ro may be the same or different, R
1□ represents hydrogen or a methoxy group. ] [In the formula, R□□ is an alkyl group having 1 to 11 carbon atoms.

It represents a substituted or unsubstituted phenyl group or a heterocyclic group, and R1□R2° may be the same or different, respectively, and is hydrogen, an alkyl group having 1 to 4 carbon atoms, or a hydroxyalkyl group.

It represents a chloralkyl group or a substituted or unsubstituted aralkyl group, and R1□ and R2゜5 may be bonded to each other to form a nitrogen-containing heterocycle. R2□ may be the same or different and represent hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkoxy group, or a halogen. ]R2□ [In the formula, R2□5 represents a hydrogen or halogen atom, and Ar4 represents a substituted or unsubstituted phenyl group, naphthyl group, anthryl group, or carbazolyl group. ] [In the formula, R13 represents hydrogen, halogen, a cyano group, an alkoxy group having 1 to 4 carbon atoms, or an alkyl group having 1 to 4 carbon atoms, Ars represents R27°, and R245 represents an alkyl group having 1 to 4 carbon atoms. , R25 represents hydrogen, halogen, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a dialkylamino group, n is 1 or 2, and when n is 2, R25 , 5 may be the same or different, and R25s and R275 represent hydrogen, a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted benzyl group. ] [In the formula, R2,5 and Ro are carbazolyl groups.

Pyridyl group, chenyl group, indolyl group.

A furyl group or a substituted or unsubstituted phenyl group, styryl group, naphthyl group or anthryl group, and these substituents are a dialkylamino group or an alkyl group.

Represents a group selected from the group consisting of an alkoxy group, a carboxyl group or an ester thereof, a halogen atom, a cyano group, an aralkylamino group, an N-alkyl-N aralkylamino group, an amino group, a nitro group, and an acetylamino group,
] (Left below) R, O.

[In the formula, R1 represents a lower alkyl group or a benzyl group, and R14 is substituted with a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom, a nitro group, an amino group, or a lower alkyl group or a benzyl group. It represents an amino group, and n represents an integer of 1 or 2. [In the formula, R32S represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, and R335 and R24
5 represents an alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group, R15
, represents a hydrogen atom or a substituted or unsubstituted phenyl group, and Ar represents a phenyl group or a naphthyl group. ] C= C-(-CH=CH+-A□ [wherein, n is an integer of 0 or 1, R36, is a hydrogen atom,
represents an alkyl group or a substituted or unsubstituted phenyl group, A4 represents a 9-anthryl group or a substituted or unsubstituted N-alkylcarbazolyl group, and R17 represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen Atom or R3g.

Indicates an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, ・R3mG and R3,
, may form a ring), m is an integer of 0, 1°2 or 3, and when m is 2 or more, R1,5
may be the same or different. ] [In the formula, R40SI R41, and R42 are hydrogen,
It represents a lower alkyl group, a lower alkoxy group, a dialkylamino group or a halogen atom, and n represents 0 or 1. ] Examples of the compound represented by the general formula (1) include 9-ethylcarbazole-3-aldehyde.

1-methyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde 1-benzyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde 1
, 1-diphenylhydrazone, etc.

Examples of the compound represented by general formula (2) include 4-diethylaminostyrene-β-aldehyde 1-methyl-1
-Phenylhydrazone, 4-methoxynaphthalene-1-
Examples include aldehyde 1-benzyl-1-phenylhydrazone.

Examples of the compound represented by the general formula (3) include 4-methoxybenzaldehyde 1-methyl-1-phenylhydrazone, 2,4-dimethoxybenzaldehyde 1-benzyl-1-phenylhydrazone, and 4-diethylaminobenzaldehyde 1,1-diphenyl hydrazone, 4-methoxybenzaldehyde 1-benzyl-1-(4-methoxy)phenylhydrazone, 4-diphenylaminobenzaldehyde 1-benzyl-1-phenylhydrazone,
Examples include 4-dibenzylaminobenzaldehyde-1,1-diphenylhydrazone.

The compound represented by general formula (4) includes, for example, 1,1
-Bis(4-dibenzylaminophenyl)propane, tris(4-diethylaminophenyl)methane, 1.1-
Bis(4-dibenzylaminophenyl)propane, 2
,2'dimethyl-4,4'-bis(diethylamino)-
Examples include triphenylmethane.

The compound represented by general formula (5) includes, for example, 9-
(4-diethylaminostyryl)anthracene, 9-bromo-IQ-(4-diethylaminostyryl)anthracene, and the like.

The compound represented by general formula (6) includes, for example, 9-
(4-dimethylaminobenzylidene)fluorene, 3-
(9-fluorenylidene)-9-ethylcarbazole and the like.

The compound represented by general formula (7) includes, for example, 1,2
-bis(4-diethylaminostyryl)benzene, 1,
2-bis(2,4-dimethoxystyryl)benzene.

The compound represented by general formula (8) includes, for example, 3-
Examples include styryl-9-ethylcarbazole and 3-(4-methoxystyryl)-9-ethylcarbazole.

The compound represented by the general formula (9) includes, for example, 4-
Diphenylaminostilbene, 4-dibenzylaminostilbene, 4-ditolylaminostilbene, 1- (4
-diphenylaminostyryl)naphthalene, 1-(4-
diethylaminostyryl) naphthylene, etc.

The compound represented by the general formula (10) includes, for example, 4'
-diphenylamino-α-phenylstilbene, 4′
-methylphenylamino-α-phenylstilbene and the like.

The compound represented by the general formula (11) includes, for example, 1-
Phenyl-3-(4-diethylaminostyryl)-5-
(4-diethylaminophenyl)pyrazoline, 1-phenyl-3-(4-dimethylaminostyryl)-5-(4
-dimethylaminophenyl)pyrazoline, etc.

Other hole transport substances include, for example, 2゜5-bis(4-diethylaminophenyl)-1゜3.4-oxadiazole, 2.5-bis[4-(4-diethylaminostyryl)phenyl]- 1,3,4-oxadiazole, 2-(9-ethylcarbazolyl-3-)-5-(4-
oxadiazole compounds such as (diethylaminophenyl)-1,3,4-oxadiazole, 2-vinyl-4-
There are low molecular weight compounds such as oxazole compounds such as (2-chlorophenyl)-5-(4-diethylaminophenyl)oxazole and 2-(4-diethylaminophenyl)-4''-phenyloxazole.
- Polymer compounds such as vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, pyrene formaldehyde resin, and ethylcarbazole formaldehyde resin can also be used.

Examples of the electron transport substance include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinone dimethane, 2,4,7-dolinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone,
2,4゜5.7-Titranitroxanthone, 2,4.8
-Trinidrothioxanthone, 2,6.8-trinitro-4H-indeno(1,2-b)thiophen-4-one, 1,3.7-trinitrodibenzothiophene-5,5
- Dioxide, etc.

These charge transport substances may be used alone or in combination of two or more.

In any of the photoreceptors obtained as described above, an adhesive layer or a barrier layer may be provided between the photoreceptors on the conductive support, if necessary.

Suitable materials for these layers include polyamide, nitrocellulose, aluminum oxide, and the like, and the film thickness is preferably 1 μm or less.

To make the photoreceptor of FIG. 1, a disazo pigment on a conductive support was prepared using
96,049, or by dispersing fine particles of a disazo pigment in a suitable solvent in which a binder is dissolved, if necessary, and dispersing this on a conductive support. After coating and drying, if necessary, the surface is finished by a method such as puff polishing as shown in JP-A No. 51-90827, or after adjusting the film thickness, a charge transporting substance and a bond are applied. It is obtained by coating and drying a solution containing the agent.

The photoreceptor shown in FIG. 2 can be prepared by dispersing fine powder of a disazo pigment in a solution containing a charge transporting substance and a binder, and coating the disazo pigment on a conductive support and drying it.

In either case, the disazo pigment used in the present invention is used after being ground to a particle size of 5 μm or less, preferably 2 μm or less, using a ball mill or the like. The coating method is carried out by conventional means such as doctor blade, dipping, wire bar, etc.

To perform copying using the photoreceptor of the present invention, the surface of the photoreceptor layer is charged and exposed, and then developed, and if necessary,
This is achieved by transferring to paper or the like.

As is clear from the above explanation and the examples below,
The electrophotographic photoreceptor of the present invention uses a disazo pigment having a diphenylamine skeleton as a charge generating substance, so it is easier to manufacture than conventional photoreceptors, and
With high sensitivity.

It has excellent properties such as stable characteristics even after repeated use of the photoreceptor.

EXAMPLES Next, the present invention will be specifically explained using Examples, but the embodiments of the present invention are not limited thereby.

Example 1 Disazo pigment! 76 parts by weight of 111174, 1260 parts by weight of a polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.) in tetrahydrofuran (solid concentration 2%), and 3700 parts by weight of tetrahydrofuran were pulverized and mixed in a ball mill, and the resulting dispersion was mixed with aluminum. It is coated onto the aluminum surface of the vapor-deposited polyester base (conductive support) using a doctor blade and air-dried to a thickness of approximately 1.
A charge generation layer of .mu.m was formed.

On this charge generation layer, 2 parts by weight of 9-ethylcarbazole-3-aldehyde 1-methyl-1-phenylhydrazone, 2 parts by weight of polycarbonate resin (Panlite -1300 manufactured by Denshi Co., Ltd.) and 16 parts by weight of tetrahydrofuran were added as charge transport substances. A solution in which the above components were mixed and dissolved was applied using a doctor blade, and dried at 80°C for 2 minutes and then at 105°C for 5 minutes to form a charge transport layer with a thickness of approximately 20 μm, resulting in the lamination shown in Figure 1. I created a type of photoconductor 1.

Example 2 The table below was used instead of the disazo pigment &74 used in Example 1.
Photoreceptor &2 was prepared in the same manner as in Example 1 except that the disazo pigment shown in Example 1 was used.

Examples 3 to 4 Example 1 except that 1-phenyl-3-(4-diethylaminostyryl)-5-(4-diethylaminophenyl)pyrazoline was used as the charge transport substance and the disazo pigment shown in Table 2 below was used. Photoreceptors &3-4 were prepared in the same manner as above.

Examples 5 to 7 Photoreceptor rods 5 to 7 were prepared in the same manner as in Example 1, except that 4'-diphenylamino-α-phenylstilbene was used as the charge transport substance and the disazo pigment shown in Table 3 below was used. did.

Examples 8 to 10 Photoreceptor N was prepared in the same manner as in Example 1, except that 1,■-bis(4-dibenzylaminophenyl)propane was used as the charge transport substance and the disazo pigment shown in Table 4 below was used.
α8-10 were created.

For these photoreceptors &1 to 10, using an electrostatic copying paper tester (Kawaguchi Electric Seisakusho, Model 5P428), -
After performing corona discharge of 6KV for 20 seconds to make it negatively charged, it was left in a dark place for 20 seconds.

The surface potential Vpo (V) at that time was measured. Next, the surface was irradiated with light using a tungsten lamp at an illuminance of 4.5 lux, and the surface potential was 1 of VPO.
Find the time (seconds) until it becomes /2, and calculate the exposure amount El/2
(looks/seconds) was calculated. The results are shown in Table-1 to Table-
4.

(Hereinafter in the margins) Table-1 Table-2 Table-3 Table-4 (Hereinafter in the margins) Layer--Two drums From the results of Tables-1 to Table-4 above, it can be seen that the photoreceptor of the present invention has high sensitivity. .

Furthermore, the photoconductor &2 of the present invention and Nαj were attached to a copying machine manufactured by Ricoh Co., Ltd.
,000 times, and as a result, clear images were obtained without any change in any of the photoreceptors due to the repetition of the copying process. From this, it can be understood that the photoreceptor of the present invention is also excellent in durability.

[Brief explanation of the drawing]

FIGS. 1 and 2 are enlarged sectional views showing an example of the structure of the photoreceptor of the present invention. FIG. 3 shows an infrared absorption spectrum (KBrBr method) of the disazo pigment 74 used in the present invention. 11... Conductive support 13... Disazo pigment 15... Charge generation layer 17... Charge transport layer 1
91.192...Photosensitive layer

Claims (1)

[Claims] 1. A disazo pigment represented by the general formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (in the formula, A represents a coupler residue) on a conductive support as an active ingredient. 1. An electrophotographic photoreceptor, characterized in that a layer containing the above-mentioned ingredients is formed.