JPH01107267A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve the sensitivity for the whole region of visible rays and the durability of an electrophotographic sensitive body by incorporating a specified azo compd. into a photosensitive layer formed on an electroconductive base body. CONSTITUTION:At least one kind of azo compd. expressed by formula I is incorporated into a photosensitive layer 4 formed on an electroconductive base body 1. In formula I, A is a coupler residue; each l and m is 1 or zero independently. This azo compd. has a tetraphenyl thiophene-1,1-dioxide skeleton, wherein 2-4 azo groups are introduced into the skeleton. These azo compds. have broad absorption characteristics in the visible rays region and are stable to light. By this constitution, an electrophotographic sensitive body having high sensitivity for wide range of visible rays region and causing no deterioration of performance against repetitive action is obtd.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an electrophotographic photoreceptor.

More specifically, the present invention relates to an electrophotographic photoreceptor in which a photosensitive layer on a conductive support contains an azo compound as a charge generating substance.

[Prior art]

Conventionally, inorganic photosensitive materials such as selenium, cadmium sulfide, and zinc oxide have been widely used as photosensitive materials for electrophotographic photoreceptors.However, photoreceptors using these photosensitive materials have poor sensitivity and photostability. However, it did not fully satisfy the required performance as an electrophotographic photoreceptor, such as moisture resistance, durability, etc.

For example, photoreceptors using selenium-based materials have excellent sensitivity, but are susceptible to crystallization due to heat or adhesion of dirt, and the characteristics of the photoreceptor deteriorate. It also has many drawbacks, such as being manufactured by vacuum deposition, which is expensive (and difficult to process into a belt because it is not flexible). Photoreceptors using cadmium sulfide materials , moisture resistance and durability, and photoreceptors using zinc oxide had problems with durability.

In order to overcome the drawbacks of photoreceptors using inorganic photosensitive materials, various photoreceptors using organic photosensitive materials have been studied.

For example, as an organic photosensitive material that has been partially put into practical use,
．． 7-) A combination of dinitro-9-fluorenone and poly-N-vinylcarbazole is known. However, photoreceptors using this method had low sensitivity and were not satisfactory in terms of durability. 'In recent years, among photoreceptors developed to improve the above-mentioned drawbacks, a functionally separated photoreceptor in which charge generation function and charge transport function are shared by separate substances has been attracting attention. In this functionally separated type photoreceptor, materials having respective functions can be selected from a wide range of materials and combined, so that it is possible to produce a photoreceptor with high sensitivity and high durability. Many materials have been proposed as charge generating materials for use in such functionally separated photoreceptors. Among these, photoreceptors using organic dyes or organic pigments as charge-generating substances have attracted particular attention in recent years.

For example, a photoreceptor using a disazo pigment having a styrylstilbene skeleton (Japanese Patent Application Laid-Open No. 133445/1983),
A photoreceptor using a disazo pigment having a carbazole skeleton (JP-A-53-95033), a photoreceptor using a trisazo pigment having a triphenylamine skeleton (JP-A-53-132347), a distyrylcarbazole skeleton A photoreceptor using a disazo pigment having
14967) and a photoreceptor using a disazo pigment having a bisstilbene skeleton (Japanese Unexamined Patent Publication No. 17733/1983).

However, although the azo compounds that have been reported so far have good sensitivity to light sources in a specific wavelength range, they have insufficient sensitivity to light sources in other wavelength ranges.

In general, the sensitivity characteristics correspond to the absorption wavelength region of the photoconductor, and although there is a slight deviation, it shows good performance for light near the maximum absorption wavelength of the pigment used in the photoconductor, and the absorption wavelength of the pigment Performance is poor for light with small wavelengths.When copying color originals using a photoreceptor that uses pigments that have absorption characteristics in a narrow wavelength range, the sensitivity varies depending on the incident wavelength light. Therefore, shading appears in the copied image depending on the color of the original.

Conventional photoreceptors using azo compounds have good reproducibility of blue parts of originals, but have been insufficient in reproducibility of red parts.

In recent years, the number of color printed matter has increased, and there are many opportunities to copy color originals, and in order to obtain copied images that do not depend on the color of the original, a photoreceptor with more uniform spectral sensitivity has been desired.

Furthermore, there has been a desire for a photoreceptor that has even better durability and can maintain stable performance under harsh usage conditions during the copying process (ozone generated during corona discharge, irradiation light, heat, etc.).

[Problem that the invention seeks to solve]

An object of the present invention is to provide an electrophotographic photoreceptor having sufficient sensitivity in the entire visible light range and good durability, and to provide a novel organic charge-generating substance for use therein. .

[Means to solve the problem]

As a result of studies to achieve the above object, the present inventors found that an azo compound having a tetraphenylthiophene-1,1-dioxide skeleton exhibits broad absorption characteristics,
The inventors discovered that it is possible to provide an electrophotographic photoreceptor having excellent characteristics of high sensitivity and high durability in the visible wavelength region, and completed the present invention as described below.

That is, the present invention provides a photosensitive layer provided on a conductive support having a compound represented by the general formula (I) (wherein A represents a coupler residue, and 2 and m are independently 1 or 0). This is an electrophotographic photoreceptor characterized by containing at least one novel azo compound.
- The azo compound of the present invention is tetraphenylthiophene-1
, 1-dioxide skeleton, and 2 to 4 azo groups have been introduced into the same skeleton.

The preferred position for substitution of the azo group is the 4-position of the phenyl group, and disazo compounds, trisazo compounds, and tetrakis compounds substituted at the 4-position of the phenyl group can be suitably used.

In general formula (I), A represents a coupler residue,
Examples of this residue include the following a) to d).

'°゛・Xpapa (wherein, group or a substituent thereof, R1 represents a hydrocarbon ring group or a substituent thereof, a heterocyclic group or a substituent thereof, a styryl group or a substituent thereof, R4 represents hydrogen, an alkyl group, a phenyl group or a substituent thereof, and R1 and R4 may form a ring together with the carbon atoms bonded thereto.) -a As X in formula (II), specifically, a naphthalene ring fused with a benzene ring to which a hydroxyl group and Y are bonded, anthracene Examples include hydrocarbon rings such as rings, and heterocycles such as indole rings, carbazole rings, benzocarbazole rings, and dibenzofuran rings.

In addition, when X has a substituent, the substituent is a chlorine atom,
Examples include halogen atoms such as bromine atoms and hydroxyl groups.

The ring group for R3 or R1 is a hydrocarbon ring group such as a phenyl group, a naphthyl group, an anthryl group, or a pyrenyl group, or a pyridyl group, a thiethyl group, a furyl group, an indolyl group, a benzofuranyl group, a carbazolyl group, or a dibenzofuran group. Examples include a heterocyclic group such as a nyl group, and examples of the ring formed by bonding P and R4 include a fluorene ring.

When R+ or R1 is a cyclic group having a substituent, the substituent is an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, or a chlorine group. Examples thereof include atom, halogen atom such as bromine atom, halomethyl group such as trifluoromethyl group, dialkylamino group such as dimethylamino group and diethylamino group, nitro group, cyano group, carboxyl group, or ester thereof.

When R2 is a phenyl group, examples of its substituent include halogen atoms such as chlorine atom and bromine atom.

b) - Maximum (III) or (IV) coupler residues.

n (In both formulas, R3 represents a substituted or unsubstituted hydrocarbon group) Specifically, R3 is an alkyl group such as a methyl group, ethyl group, propyl group, butyl group, or octyl group, or a methoxyethyl group. , an alkoxyalkyl group such as an ethoxyethyl group, and the like.

C) - Maximum (V) coupler residue.

(In the formula, Rh represents an alkyl group, a carbamoyl group, a carboxyl group, or an ester group thereof, and R1 represents a hydrocarbon ring group or a substituted product thereof.) Specifically, R1 is a phenyl group, a naphthyl group, etc. When these groups have substituents, the substituents include alkyl groups such as methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy, and butoxy groups. Examples include alkoxy groups such as groups, dialkylamino groups such as dimethylamino groups and diethylamino groups, halogen atoms such as chlorine atoms and bromine atoms, nitro groups, and cyano groups.

d) - maximum (Vl) or (■) coupler residue +I
0 (In both formulas, Z is a divalent group of a hydrocarbon ring or a substituent thereof,
(representing a divalent heterocyclic group or a substituent thereof),
Specifically, divalent groups of monocyclic aromatic hydrocarbons such as 0-phenylene group, 0-naphthylene group, peri-naphthylene group, 1,2-anthraquinonylene group, 9. A divalent group of a condensed polycyclic aromatic hydrocarbon with an IO-phenanthrylene group, or a 3,4-pyrazolediyl group, a 2.3-pyridinediyl group, a 4.5-pyrimidinediyl group, a 6.7-
Examples include heterocyclic divalent groups such as an imidazolediyl group, a 5,6-benzimidazolediyl group, and a 6,7-chiralindiyl group. When these ring groups have a substituent, examples of the substituent group include alkyl groups such as methyl, ethyl, propyl, and methyl; alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy; Examples include dialkylamino groups such as dimethylamino group and diethylamino group, halogen atoms such as chlorine atom and bromine atom, nitro group, and cyano group.

Specific examples of coupler residues are shown below.

0CH3 0C2H5 H3 H3 CH3 N (CH3) 2 'CN Among the above-mentioned coupler residues, the -maximum (II ) The coupler residues represented by i are most preferred.

Specific examples of the azo compound used in the present invention include those represented by the following structural formula.

The compounds of the present invention can be manufactured using the following method.

-I Diazotize the amine compound represented by formula (■) (where l and m are the same as in general formula (I)), and then isolate the diazotized compound as it is or as a borofluoride salt. After that, it can be easily produced by coupling with the above coupler compound.

The electrophotographic photoreceptor of the present invention contains at least one azo compound represented by the general formula (I) as a charge generating substance in a photosensitive layer on a conductive support. A typical structure of such a photoreceptor is shown in FIGS. 9 and 10. What is shown in FIG. 9 is a photoreceptor in which a dispersion type photosensitive layer 4 in which a charge generating substance 2 and a charge transporting substance 3 are dispersed in a binder is provided on a conductive support 1. A photosensitive layer 4 is provided on a conductive support 1, and includes a charge-generating layer 6 in which a charge-generating substance is dispersed in a binder, and a charge-transporting layer 5 in which a charge-transporting substance is dispersed in a binder. It is the body.

Other examples include those in which the charge generation layer and charge transport layer are reversed, and those in which an intermediate layer is provided between the photosensitive layer and the conductive support.

In the photoreceptor shown in FIG. 10, imagewise exposed light passes through the charge transport layer, and a charge generation substance generates charges in the charge generation layer. The generated charge is a charge.

The charge transport material is injected into the transport layer and performs the transport.

The electrophotographic photoreceptor of the present invention is constituted by containing, in addition to the azo compound (I), a conductive support, a binder, a charge transport material, etc., and other components of the photoreceptor include the photoreceptor. It is not particularly limited as long as it functions as a component of.

That is, the conductive support used in the photoreceptor of the present invention includes a metal plate made of aluminum, copper, zinc, etc., a plastic sheet or film made of polyester, etc., on which a conductive material such as aluminum, SnO2, etc. is vapor-deposited; Conductive treated paper, resin, etc. are used.

As binders, vinyl polymers such as polystyrene, polyacrylamide, poly-tovinylcarbazole, polyamide resins, polyester resins, epoxy resins,
Condensation resins such as phenoxy resin and polycarbonate resin are used, but any resin that is insulating and has adhesiveness to the support can be used.

Charge transport materials are classified into -1G into two types, hole transport materials and electron transport materials, and both can be used in the photoreceptor of the present invention. Examples of hole-transporting materials include electron-accepting materials that easily transport electrons, such as trinitrofluorenone and tetranitrofluorenone, as well as poly-N-
Polymers containing heterocyclic compounds such as vinyl carbazole, triazole derivatives, oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives, polyarylalkane derivatives, phenylenediamine derivatives, hydrazone derivatives, amino-substituted chalcone derivatives, triaryl Examples include electron-donating substances that easily transport holes, such as amine derivatives, carbazole derivatives, and stilbene derivatives.

For example, 9-ethylcarbazole-3-aldehyde-
1-Methyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde-1-benzyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde-1,1-diphenylhydrazone, 4-diethylaminostyrene-β- Aldehyde-1-methyl-1-phenylhydrazone, 4-methoxynaphthalene-1-aldehyde-1-benzyl-1-phenylhydrazone, 4-methoxybenzaldehyde-1-methyl-1-phenylhydrazone, 2,4-dimethoxybenzaldehyde- r-benzyl-1-phenylhydrazone, 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, 4
-methoxybenzaldehyde-1-benzyl-1-(4
-methoxy)phenylhydrazone, 4-diphenylaminobenzaldehyde-1-benzyl-1-phenylhydrazone, 4-dibenzylaminobenzaldehyde-1,
1-diphenylhydrazone, 1.1-bis(4-dibenzylaminophenyl)propane, tris(4-diethylaminophenyl)methane, 1.1-bis(4-dibenzylaminophenyl)propane, 2,2”-dimethyl -4
, 4'-bis(diethylamino)-triphenylmethane, 9-(4-diethylaminostyryl)anthracene,
9-bromo-10-(4-diethylaminostyryl)anthracene, 9-(4-dimethylaminobenzylidene)
Fluorene, 3-(9-fluorenonedene)-9-ethylcarbazole, 112-bis(4-diethylaminostyryl)benzene, 1,2-bis(2,4-dimethoxystyryl)benzene, 3-styryl-9-ethylcarbazole , 3-(4-methoxystyryl)-9-ethylcarbazole, 4-diphenylaminostilbene, 4-dibenzylaminostilbene, 4-ditolylaminostilbene, 1-(4-diphenylaminostyryl)naphthalene, 1-(4-diphenylaminostilbene) -diethylaminostyryl) naphthalene,
4'-diphenylamino-α-phenylstilbene, 4
゛-Methylphenylamino-α-phenylstilbene,
1-phenyl-3-(4-diethylaminostyryl)-
5-(4-diethylaminophenyl)pyrazoline, 1-
Phenyl-3-(4-dimethylaminostyryl)-5
-(4-dimethylaminophenyl)pyrazoline and the like.

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
-diethylaminophenyl)-1,3,4-oxadiazole, 2-vinyl-4-(2-chlorophenyl)-5
-(4-diethylaminophenyl)oxazole, 2-
(4-diethylaminophenyl)-4-phenyloxazole, 9- (3-(4-diethylaminophenyl)
-2-propenylidene]-9toxanthene, poly-N-
Examples include vinyl carbazole, halogenated poly-N-vinyl carbazole, polyvinylpyrene, polyvinylanthracene, pyrene formaldehyde resin, ethinocycarbazole formaldehyde resin, and the like.

Examples of the electron transport substance include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4.7-)linitro-9-fluorenone, 2,4.5.7-tetranitro-9-fluorene, 2
, 4.5.7-tetranitroxanthone, 2,4.8-
) linitrothioxanthone, 2,6.8-trinitro-4toindeno(I,2-b)thiophen-4-one, 1,3.7-trinitrodibenzothiophene-5.5
- Dioxide, etc.

These charge transport materials may be used alone or in a mixture of two or more.

An intermediate layer can be provided between the photosensitive layer and the conductive support if necessary, and suitable materials include polyamide, nitrocellulose, casein, polyvinyl alcohol, and the like, and the film thickness is preferably 1 μm or less.

Conventionally known methods can be used to manufacture the photoreceptor. For example, in the photoreceptor, fine particles of a disazo compound are dispersed in a solution containing a binder, coated on a conductive support, and dried to obtain a charge generation layer.Then, the charge transport material and the binder are dissolved. A charge transport layer can be created by applying a solution and drying it. Other methods can also be used to make the charge generating layer. For example, there is a method of vacuum-depositing azo pigments, or a method of applying and drying a solution of azo pigments, but the former method is expensive, and the latter method uses organic amines such as ethylenediamine and n-butylamine, which are generally difficult to handle. Since there are some drawbacks in production, the method of coating a fine particle dispersion of an azo compound is preferred. Application is carried out by conventional means, such as doctor blade, dipping, wire bar, etc. The optimum thickness of the photosensitive layer varies depending on the type of photoreceptor. For example, in the case of a photoreceptor as shown in FIG. 9, the thickness is preferably 3 to 50 .mu.m, more preferably 5 to 30 .mu.m.

Further, in the photoreceptor shown in FIG. 10, the thickness of the charge generation layer 6 is preferably 0.01 to 5 .mu.l, more preferably 0.05 to 2 .mu.l. If the thickness is less than 0.01 μm, charge generation will not be sufficient, and if it exceeds 5 μm, the residual potential will be high and it is not practical. More preferably, the thickness is from 5 to 30 μm; if the thickness is less than 3 μm, the amount of charge will be insufficient, and if it exceeds 50 uffi, the residual potential will be high and it is not practical.

The content of the azo compound represented by the general formula (I) in the photosensitive layer varies depending on the type of photoreceptor, but in the photoreceptor shown in FIG. 9, it is preferably 50% by weight in the photosensitive layer 4. below,
More preferably, it is 20% by weight or less. Further, this layer preferably contains a charge transport material in a proportion of 10 to 95% by weight, more preferably 30 to 90% by weight. Also,
In the photoreceptor shown in FIG. 10, the proportion of the azo compound in the charge generation layer 6 is preferably 30% by weight or more, more preferably 50% by weight or more. In addition, 5 in the charge transport layer
The charge transport material is contained in an amount of 10 to 95%, preferably 30%.
It is contained at ~90% by weight. If the amount of the charge transport material in this layer is less than 10% by weight, almost no charge is transported, and if it exceeds 95% by weight, the mechanical strength of the photoreceptor deteriorates, which is not preferred in practice.

[Action and effect]

, the azo compound having a tetraphenylthiophene-1,1-dioxide skeleton of the present invention has very broad absorption characteristics in the visible light region and is stable to light,
A photoreceptor using this as a charge-generating material has a high frequency range over a wide range of visible light, and has excellent performance that does not deteriorate under repeated action.

(The following is a blank space) Examples The present invention will be specifically explained by examples below, but the present invention is not limited thereto.

Production Example 1 In a solution consisting of 35% hydrochloric acid 17 and water 12
After dispersing 20 g of bis(4-aminophenyl)-3,4-diphenylthiophene-1,1-dioxide and stirring at room temperature for 3 hours, 18.4 g of sodium nitrite was dissolved in 30 g of water.
A solution dissolved in 0m was added dropwise at 0°C. After stirring at the same temperature for 3 hours, insoluble materials were removed and 100 d of 42% fluoroboric acid was added. The precipitated crystals were separated by filtration, washed with water, and dried to obtain 24.9 g (yield: 87.3%) of a tetrazonium salt.

10 g of tetrazonium salt and 8.5 g of 2-hydroxy-3-naphthoic acid anilide (trade name: Naphthol AS) were mixed with N
, N-dimethylformamide was dissolved in 1.52 kg, 100 ml of 5% aqueous sodium acetate solution was added dropwise at 5°C, and the mixture was stirred at the same temperature for 2 hours. After further stirring at room temperature for 5 hours, the precipitated crystals were filtered off and diluted with N,N-dimethylformamide 50
Sludged at 0d and filtered. This sludge operation
After repeating the process 4 times, remove the sludge with water and filter it 4 times.
Repeated times. Dry the filter cake to obtain Exemplified Compound No. 1
12 g (yield 78.1%) of a disazo compound was obtained. The resulting powder exhibited a black color and did not melt at temperatures below 300''C.

It was confirmed to be the desired product based on elemental analysis values and infrared absorption spectrum (KBr method).

Elemental analysis value: CINS actual value (%)
? 4.21 4.16 8.33 3.42 Calculated value (%)? 4.55 4.21 8.42
3.21 Infrared absorption spectrum: Absorption 1670 cra-' based on >C=O The infrared absorption spectrum (KBr method) is shown in FIG.

Production Example 2 A benzocarbazole compound represented by the following structural formula and 14 g of the tetrazonium salt synthesized in Production Example 1 were mixed with N,N
-Dissolved in dimethylformamide 12. 140 d of 5% sodium acetate aqueous solution was added dropwise at 0 to 5°C, and at the same temperature
After stirring for an hour, the mixture was stirred at room temperature for 5 hours. The precipitate was separated by filtration, and the sludge and filtration were repeated three times with 11 parts of N,N-dimethylformamide, and the sludge and filtration were repeated 6 times with 1.5 parts of water. Dry the filter cake to obtain Exemplary Compound No. 5
18.6 g (yield 69.6%) of a disazo compound was obtained. The obtained powder exhibited a brownish black color and did not melt at temperatures below 300°C.

Elemental analysis and infrared spectrum (KBr method) confirmed that the product was the desired product.

Elemental analysis value: CINS actual value (%)
73.61 4.34 8.80 2.78 Calculated value (%) 73.79 4.21 9.06
2.59 Infrared absorption spectrum: >Absorption 1660 CIm-' based on C=O The infrared absorption spectrum (KBr method) is shown in FIG.

Production Example 3 5.6 g of 2.3.5-tris(4-aminophenyl)-4-phenylthiophene-1,1-dioxide was
% hydrochloric acid and 500 d of water. A solution of 3.0 g of sodium nitrite dissolved in 20 d of water was added dropwise at 0°C. After stirring at the same temperature for 2 hours,
42% fluoroboric acid (50%) was added to the reaction solution. The resulting brown starch was filtered and thoroughly pressed.

Then, the obtained borofluoride salt was diluted with naphthol A at O″C.
395 g was added to 600!11 of the dissolved N,N-dimethylformamide solution. 8g of sodium acetate and 60d of water
A solution dissolved in was added dropwise over 30 minutes at 0 to 5°C, and after stirring at the same temperature for 1 hour, the temperature was returned to room temperature and stirred for 5 hours. The precipitated crystals were filtered off and washed with N.

The mixture was sludged with 400 d of N-dimethylformamide and collected by filtration. After repeating this operation, sludge with water If
The filtration operation was repeated four times. After drying, the compound No.
, 11 g (yield 72%) of the trisazo compound of 11 was obtained. The obtained powder exhibited a brownish black color and did not melt at temperatures below 300'C.

It was confirmed by elemental analysis and infrared absorption spectrum (KBr method) that it was the desired product.

Elemental analysis value: CINS actual value (%)
? 3.34 4.05 9.80 2.50 Calculated value (%”) 73.66 4.12 9.79
2.49 Infrared absorption spectrum: >Absorption 1675C1-' based on C=O The infrared absorption spectrum (KBr method) is shown in FIG.

Production Example 4 Synthesized in the same manner as in Production Example 3 except that naphthol AS-3G was used instead of naphthol As, and the exemplified compound N
α16 was obtained. The obtained powder was black in color and heated at 300'C.
It did not melt below.

It was confirmed by elemental analysis and infrared absorption spectrum (KBr method) that it was the desired product.

Elemental analysis value: CHN S Actual value (%)? 2.62 4.03 10.21
2.01 Calculated value (%) 72.99 4.14
10.22 1.95 Infrared absorption spectrum:
The absorption 1660 cm-' infrared absorption spectrum (KBr method) based on >C=O is shown in FIG.

Production Example 5 Tetrakis(4-aminophenyl)thiophene-1,1
- 8.0 g of dioxide were dissolved in a solution consisting of 18 ml of 35% hydrochloric acid and 500 Id of water. A solution of 5:5 g of sodium nitrite dissolved in 30 mft of water was heated with O'C for 3
It was added dropwise over 0 minutes. After stirring for 2 hours at o'c, 42
% fluoroboric acid was added and stirred for 30 minutes.

The resulting precipitate was filtered, washed with a small amount of ethanol ether, and air-dried to give 12.7 g of tetrakisborofluoride salt (yield: 87
%) was obtained.

Naphthol A in N,N-dimethylformamide 400d
After cooling to O''C, 3.0 g of tetrakisborofluoride salt was added and stirred for 15 minutes.

A solution of 2.5 g of sodium acetate dissolved in 20 d of water is
The mixture was added dropwise over 20 minutes at °C, stirred at the same temperature for 1 hour, and then at room temperature for 4 hours. The formed crystals were filtered out, and N,N
- After repeating the sludge and filtration operation with 300 d of dimethylformamide three times, the sludge and filtration operation with water 11 was repeated six times. After drying, 4.3 g (yield: 79%) of the tetrakisazo compound No. 21 was obtained.

The obtained powder exhibited a brownish black color and did not melt at temperatures below 300°C.

It was confirmed by elemental analysis and infrared absorption spectrum (KBr method) that it was the desired product.

Elemental analysis value: CHN S Actual value (%)? 3.42 4.03 10.71
1.94 Calculated value (%)? 3.10 4.06
10.66 2.03 Infrared absorption spectrum:
>C=0 Absorption 1675cm'' Infrared absorption spectrum (KBr method) is shown in FIG.

Production Example 6 Synthesized in the same manner as Production Example 5 except that naphthol AS-SG was used instead of naphthol AS, and exemplified compound No.
I got 28. The obtained powder exhibited a black color and did not melt at temperatures below 300°C.

It was confirmed by elemental analysis and infrared absorption spectrum (KBr method) that it was the desired product.

Elemental analysis value: CHN S Actual value (%)? 2.78 4.13 10.88
1.47 Calculated value (%) 72.51 4.09
10.92 1.56 Infrared absorption spectrum:
The absorption 1660 cta-' infrared absorption spectrum (KBr method) based on >C=O is shown in FIG.

Production Examples 7 to 20 Similarly, the amine compound represented by -max (■) was diazotized and then reacted with the corresponding coupler.

Table 1 shows the elemental analysis values and infrared absorption spectrum (KBr method; νC=0) of the obtained compound.

Table-1 Example 1 Polyester resin (product name "Adhesive 49000")
(manufactured by DuPont) 0.5 parts, 0.5 parts of Exemplified Compound No. 1
and 50 parts of tetrahydrofuran were pulverized and mixed in a ball mill, and the resulting dispersion was coated on an aluminum plate using a wire bar and dried at 80°C for 20 minutes to form a charge generation layer of about 1 μm. A solution prepared by dissolving 1 part of 9-ethylcarbazole-3-aldehyde-1-methyl-1-phenylhydrazone and 1 part of polyester resin (trade name: "Vylon 200", Toyo Dobu Co., Ltd.) in 10 parts of chloroform was placed on the charge generation layer. The coating was applied using a wire bar and dried at 80''C for 30 minutes to form a charge transport layer having a thickness of about 18 microns, thereby producing a laminated photoreceptor shown in FIG. 10.

Electrostatic copying paper testing device (Model EP manufactured by σKodenki Seisakusho)
A-8100) was used to charge the photoreceptor by corona discharge at an applied voltage of -6 KV, the surface potential v0 at that time was measured, and the surface potential V0 at that time was measured after being left in a dark place for 2 seconds.

Then, with the surface illuminance of the photoconductor at 51ux, light from a halogen lamp (color temperature 2856°K) was irradiated to measure the time for the surface potential to reach 18 of v2, and half-reduction exposure IE was performed. '/z (Iux-sec) was calculated.

Furthermore, the surface potential VR, that is, the residual potential, was measured after 10 seconds of light irradiation.

Examples 2 to 19 Photoreceptors were prepared in the same manner as in Example 1 except that the compounds shown in Table 2 were used in place of Exemplified Compounds No. 1 and 1, respectively, and E'8 was determined and the results are shown in Table 1. -2.

Table 2 Examples 20 to 32 1-phenyl-3-(4-diethylaminostyryl) instead of 9-ethylcarbazole-3-aldehyde-1-methyl-1-phenylhydrazone as charge transport substance
-5-(4-diethylaminophenyl) Azo compound shown in Table 3 using pyrazoline as a charge generating substance.

A photoreceptor was prepared in the same manner as in Example 1 except that E'
/l was calculated. The results are shown in Table-3.

Table 3 Examples 33 to 45 2.5-bis(4-diethylaminophenyl)-1, instead of 9-ethylcarbazole-3-aldehyde-1-methyl-1-phenylhydrazone as a charge transport substance.
A photoreceptor was prepared in the same manner as in Example 1, except that 3,4-oxadiazole was used and the azo compound shown in Table 4 was used as the charge generating substance, and El8 was determined. The results are shown in Table-4.

Table 4 Comparative Example 1 A photoreceptor was prepared in the same manner as in Example 1, except that a disazo compound represented by the following structural formula and described in Japanese Patent Publication No. 55-42380 was used as a charge generating substance.

E1/2 was 12.0 (lux·sec).

Example 46 Illustrated compound No. 28 was dispersed together with a solvent and a binder in the same manner as in Example 1, applied to a glass plate, and dried.

Double beam self-recording spectrophotometer (UV manufactured by Shimadzu Corporation)
-240), the absorption spectrum was measured.

As one standard for determining the broadness of an absorption curve, the half-width (wavelength range having an absorbance of 172 or more with respect to the maximum absorbance in the wavelength range of 400 to 700 nm) was defined.

The half width was 300 nm (400-700 rv). The absorption spectrum is shown in FIG.

Comparative Example 2 In the same manner as in Example 1, an azo compound represented by the following structural formula described in JP-A No. 62-47053 was dispersed together with a solvent and a binder and applied to a glass plate. In the same manner as in Example 46, the half width was determined from the absorption spectrum. The half width is 218nm (432~650n+m
)Met.

The absorption spectrum is shown in FIG.

Example 47 Photoreceptors were prepared using the azo compounds of Exemplified Compounds No. 28 and Comparative Example 2, and installed in a commercially available copying machine.
Color manuscripts were copied and compared.

When the former photoreceptor was used, a copy image with excellent reproducibility of the red part of the original was obtained, but with the latter photoreceptor, only a copy image where the red part of the original was thin and unclear was obtained.

Examples 48 to 50 Exemplary compounds No. 1, No. 16 and No. 21 were applied to a glass plate in the same manner as in Example 1,
It was dried and a test piece was prepared. The test piece was irradiated with carbon arc light for 50 hours using a fetometer test device (FAL-5, manufactured by Suga Test Instruments). For all three test pieces, almost no change in hue was observed after irradiation compared to before irradiation.

Comparative Examples 3 to 4 Two types of azo compounds represented by the following structural formulas described in JP-A No. 62-47053 were subjected to a light irradiation test in the same manner as in Example 48. Both test pieces showed significant discoloration after light irradiation. was recognized.

Example 51 Using the photoreceptors prepared in Examples 9, 12 and 16,
The charging exposure operation was repeated 1000 times to obtain the values shown in Table 5.

As described above, the electrophotographic photoreceptor of the present invention can be said to have high sensitivity and uniform spectral characteristics, stable performance even after repeated use, and excellent durability.

The photoreceptor of the present invention can be used not only in electrophotographic copying machines, but also in various printers, electrophotographic engraving systems, etc. that apply electrophotographic copying principles.

[Brief explanation of the drawing]

Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, and Fig. 6 are respectively exemplified compounds No. 1, No. 5, No. 11, and N.
Figures 7 and 8 show the infrared absorption spectra (KBr method) of No. o, 16, No. 21, No. 28, respectively. The visible light absorption spectrum of the layer is shown. 9 and 10 are cross-sectional views showing an example of the structure of an electrophotographic photoreceptor. Note that in FIGS. 9 and 10, each reference numeral is as follows. 1...-Electroconductive support 4...-Photosensitive layer 2-
・-・Charge generating substance 5-・−・Charge transport layer 3...
---Charge transport material 6----Charge generation layer. Patent Applicant: Mitsui Toatsu Chemical Co., Ltd. Drawings Figure 1 Wave number (cm-') Figure 2 Wave number (cm-') Figure 3 Wave number (cm-') Figure 4 Wave number (crrr') Figure 5 Wave number ( cm-') Figure 6 Wave number (cm-') Figure 7 400 500 600 700- Bo. Wavelength (nm) Figure 8 Wavelength (nm) Figure 9] Figure 10

Claims (1)

[Claims] 1) In the photosensitive layer provided on the conductive support, the general formula (
I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, A represents a coupler residue, and l and m are independently 1 or 0.) At least one azo compound represented by An electrophotographic photoreceptor comprising: