JPH04172357A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To ensure the high sensitivity and less residual potential of an electrophotographic sensitive body, and improve the durability thereof by providing a sensitive layer containing the specified bisazo compound on a conductive base material. CONSTITUTION:A sensitive layer containing such a bisazo compound as shown in the expression I or II is provided on a conductive base material. In the expression II, Cp stands for coupler residues respectively having an independent phenol hydroxyl group, R<1> to R<4> for substituents respectively, m<1> to m<4> for integers of 0 to 4 respectively, and m<2> and m<3> for integers of 0 to 2 respectively. High sensitivity and color sensitivity can be obtained by allowing a combination with a wide range of carrier transport generation substances, and containing the specified bisazo compound high in carrier generation capability, as aforementioned. In addition, the fluctuation of sensitivity, electrifying characteristics and residual potential are reduced, even when the sensitive body is repeatedly used, and the durability thereof can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor having a photosensitive layer containing a bisazo compound.

[Prior Art] Conventionally, inorganic photoreceptors having a photosensitive layer containing an inorganic photoconductive compound such as selenium, zinc oxide, cadmium sulfide, or silicon as a main component have been widely used as electrophotographic photoreceptors. However, these are not necessarily satisfactory in terms of sensitivity, thermal stability, moisture resistance, durability, etc. For example, when selenium crystallizes, its properties as a photoreceptor deteriorate, making it difficult to manufacture.Also, selenium crystallizes due to heat, fingerprints, etc., and its performance as a photoreceptor deteriorates. Furthermore, cadmium sulfide has problems with moisture resistance and durability, while zinc oxide has problems with durability.

In order to overcome these drawbacks of inorganic photoreceptors, research and development of organic photoreceptors having photosensitive layers mainly composed of various organic photoconductive compounds has been actively conducted in recent years. For example, Japanese Patent Publication No. 50-10496 describes an organic photoreceptor having a photosensitive layer containing poly-N-vinylcarbazole and 2,4,7-)Lielow-9-fluorenone. However, this photoreceptor is not always satisfactory in terms of sensitivity and durability. For this reason, attempts have been made to develop organic photoreceptors with higher performance by assigning the carrier generation function and the carrier transport function to different substances, respectively.

There are two types of so-called function-separated type photoreceptors: single-layer type and laminated type.For both, materials can be selected from a wide range, and photoreceptors with arbitrary performance can be compared. A lot of research has been done on it because it is easy to create. In such functionally separated photoreceptors, many compounds such as organic dyes and organic pigments have been proposed as carrier generating substances having a carrier generating function. For example, JP-A-54-22834, JP-A No. 55-730
No. 57, No. 55-117151, No. 56-46237
There are descriptions of electrophotographic photoreceptors containing an azo compound, particularly a bisazo compound, in the photosensitive layer.

[Problems to be Solved by the Invention] However, the bisazo compounds described in the above publications are not necessarily satisfactory in terms of sensitivity, residual potential, or stability during repeated use. The selection range is also limited, and the wide range of demands of electrophotographic processes cannot be fully satisfied.

The present invention has been made to solve the above problems,
An object of the present invention is to provide an electrophotographic photoreceptor containing a specific bisazo compound having excellent carrier generation ability.

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

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

[Means for Solving the Problem] As a result of intensive research to achieve the above object, the present inventors have found that a specific bisazo compound can act as an excellent active ingredient for electrophotographic photoreceptors. They discovered this and completed the present invention. That is, the above object of the present invention is to provide an electrophotographic photoreceptor characterized by having a photosensitive layer containing a bisazo compound represented by the following general formula [I] or [I] on a conductive support. It can be achieved.

General formula [I] [In the formula, Cp each independently represents a coupler residue having a phenolic hydroxyl group, R1, RR.

R1 and R4 each represent a substituent, ml and m4
each represents an integer of 0 to 4, and ml and m3 each represent an integer of 0 to 2. General Formula II] [In the formula, Cp each independently represents a coupler residue having a phenolic hydroxyl group, R1 and R4 each represent a substituent, and ml and m4 each represent an integer of O to 4. The present invention will be explained in more detail below.

In the general formula [I] or in the general formula [II, two -N=N-Cp are each contained, and in the general formula [I], RL,
R'', wherever R8 or R4 may be substituted,
Further, in the general formula [II], R1 or R4 can be bonded to any position where it can be substituted. However-N
It is assumed that the values of m', m'', m'', and m' change appropriately depending on the substitution position of =N-Cp. Two Cp's in the formula may be the same or different. In addition, in the present invention, m", m
'.

When the values of m3 and m4 are each 2 or more, m' R1, m2 R", m" R1, and m4 R4 may be the same or different.

Cp represents a coupler residue having a phenolic hydroxyl group, and the phenolic hydroxyl group here refers to a hydroxyl group substituted on an aromatic hydrocarbon ring, and this aromatic hydrocarbon ring further has a hydrocarbon ring. Alternatively, the heterocycles may be fused.

Specifically, coupler residues represented by the following general formulas [II[] to [XII] may be mentioned.

General formula [ITI] (wherein, Y and Y2 are each independently a hydrogen atom,
Halogen atom, alkyl group, aryl group, heterocyclic group, alkoxy group, aryloxy group, aralkyloxy group,
It represents a carboxyl group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a hydrazinocarbonyl group, an acyl group, or an acylamino group. ) General formula [rV] (wherein Y3 is each independently a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a heterocyclic group, an alkoxy group, an aryloxy group, an aralkyloxy group, a carboxyl group, an alkoxycarbonyl group, 2 represents an aryloxycarbonyl group or an acyl group, and 2 is fused with a benzene ring to form an aromatic hydrocarbon ring or a heterocycle.
Indicates a valence group. ) General formula [V] (In the formula, Rt and R1 each represent a hydrogen atom, a lower alkyl group, an aryl group, or a heterocyclic group, and R1 and R2
may be bonded to each other to form a ring. Z has the same meaning as in the general formula [IV]. ) General formula [VI] (wherein, R, , R, and Z each represent the general formula [VI]
V]. ) General formula [■] (In the formula, R and R1 each represent a hydrogen atom, an alkyl group, an unsaturated alkyl group, an aryl group, a heterocyclic group, a vinyl group, or a butadienyl group, and Rs and R4 bond to each other. may form a ring.Z may be represented by the general formula [
rV]. ) General formula [■] (wherein, R1 and R3 each represent the general formula [V]
or has the same meaning as in general formula [■]. ) General formula [■ ko (wherein, R1 and Z are each the above general formula [TV]
or has the same meaning as in [V]. ) General formula [XcoR1 (In the formula, R6 represents an alkyl group, an unsaturated alkyl group, or an aryl group.) General formula [XI] [In the formula, Rs, Rt, Re and R1 are each a hydrogen atom, R6 represents a halogen atom, an alkyl group, a vinyl group, a substituted amino group or an aryl group, and R6 also represents CRt
. (However, RIO represents an alkyl group, an aryl group, a heterocyclic group, a vinyl group, an amino group, or an alkoxy group.) ] General formula [Xn] (In the formula, Q represents a divalent aromatic hydrocarbon group or a divalent heterocyclic group.) However, each group in the above general formulas [I11] to [XII] has a substituent. may have.

In each of the general formulas [nI] to [XI], the 7”% rogen atom is a fluorine atom, a chlorine atom, a bromine atom,
Examples of substituted or unsubstituted alkyl groups include methyl, ethyl, n-propyl, n-butyl, isobutyl, tert-butyl, n-hexyl, and n-octyl groups. , benzyl group, p-
Methylbenzyl group, p-chlorobenzyl group, 2-phenylethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, allyl group, 2-hydroxyethyl group, 2-methoxyethyl group, 3-morpholinopropyl group, Examples include 2-diethylaminoethyl group and 3-carbazolylmethyl group. The lower alkyl group represented by R8 usually represents an alkyl group having 1 to 6 carbon atoms.

Examples of the aryl group include aromatic hydrocarbon groups such as phenyl group, naphthyl group, anthryl group, pyrenyl group, fechyntolyl group, anthraquinolyl group, acenaphthyl group, fluorenyl group, biphenylyl group, p-terphenylyl group, and p-styrylphenyl group. These substituents include alkyl groups such as methyl, ethyl, and butyl; halogen atoms such as fluorine, chlorine, bromine, and iodine; alkoxy groups such as methoxy, ethoxy, and butoxy;
Aryloxy groups such as phenoxy groups; hydroxyl groups; nitro groups; cyano groups; amino groups; substituted amino groups such as dimethylamino groups, diethylamino groups, and dibenzylamino groups;
Carboxyl group; alkoxycarbonyl group such as ethoxycarbonyl group; aryloxycarbonyl group such as phenyloxycarbonyl group; acyloxy group such as acetoxy group, benzoyloxy group; acyl group such as acetyl group, benzoyl group; carbamoyl group, dimethylamino carbonyl group,
Substituted aminocarbonyl groups such as a phenylaminocarbonyl group; arylalkoxy groups such as a benzyloxy group and a phenethyloxy group; and the like.

Examples of the heterocyclic group include furyl group, thienyl group, thiazolyl group, indolyl group, pyrrolyl group, carbazolyl group, pyridyl group, morpholino group, quinolyl group, imidazolyl group,
Examples include oxasilyl group, triazolyl group, piperidyl group, benzoxacylyl group, benzimidazolyl group, benzothiazolyl group, acridyl group, xanthenyl group, phenazinyl group, phenothiazinyl group, coumarinyl group, etc., and have the same substituents as the aryl group. You may do so.

Examples of the alkoxy group include methoxy group and ethoxy group, and examples of the aryloxy group include phenoxy group and p-
Examples of the aralkyloxy group include a chlorophenoxy group, p-methylphenoxy group, and 1-naphthoxy group, and examples of the aralkyloxy group include a benzyloxy group and a phenethyloxy group.

Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group, and examples of the aryloxycarbonyl group include a phenoxycarbonyl group and a 1-
Examples include naphthoxycarbonyl group.

Z is fused with a benzene ring to form a naphthalene ring, anthracene ring, carbazole ring, benzocarbazole ring,
Examples include divalent groups required to form an aromatic hydrocarbon or a heterocycle such as a dibenzofuran ring.

Examples of the ring group formed by bonding R1 and R1 to each other include a cyclohexylidene group, an indenylidene group, a fluorenylidene group, a pentamethylene group, and the like.

Examples of unsaturated alkyl groups include allyl group, 3-butenyl group, cinnamyl group, and the like.

Q in general formula [XII] may have a substituent 2
It represents a valent aromatic hydrocarbon group or a divalent heterocyclic group which may have a substituent. Examples of the divalent aromatic hydrocarbon group include a divalent monocyclic aromatic hydrocarbon group such as an 0-phenylene group, an 0-naphthylene group, a 1,8-naphthylene group,
Examples include divalent condensed polycyclic aromatic hydrocarbon groups such as 1.2-anthraquinonylene group and 9.10-fechintolylene group.

Further, as the divalent heterocyclic group, for example, a 3゜4-pyrazolediyl group, a 2,3-pyridinediyl group, a 3.4-
pyridinediyl group, 4.5-pyrimidinediyl group, 6,
7-Indazolediyl group.

Divalent heterocyclic groups such as 5.6-benzimidazolediyl group and 5.6-chiralindiyl group can be mentioned.

Examples of substituents for these groups include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group,
Alkyl groups such as i-butyl group and n-hexyl group; trifluoromethyl group; alkoxy groups such as methoxy group, ethoxy group, propoxy group, butoxy group; hydroxyl group; nitro group; cyano group; amino group; dimethylamino group , substituted amino groups such as diethylamino group, dibenzylamino group;
Halogen atoms such as fluorine atom, chlorine atom, bromine atom, iodine atom; carboxyl group; alkoxycarbonyl group such as ethoxycarbonyl group; carbamoyl group; acetyl group,
Acyl groups such as benzoyl groups; aryloxy groups such as phenoxy groups; arylalkoxy groups such as benzyloxy groups;
Examples include aryloxycarbonyl groups such as phenyloxycarbonyl groups. Among them, alkyl groups, alkoxy groups,
A nitro group, a halogen atom, a hydroxyl group or a carbamoyl group, particularly a methyl group, a methoxy group, a nitro group, a chlorine atom or a hydroxyl group are preferred.

In the present invention, the coupler residue Cp has the general formula [V1]
, [■] or [XII] is particularly preferred.

In general formula [1] or general formula [II], the substituents represented by R1 to R4 include alkyl groups such as methyl group, ethyl group, butyl group; fluorine, chlorine, bromine,
Halogen atoms such as iodine; alkoxy groups such as methoxy, ethoxy, and butoxy groups; aryloxy groups such as phenoxy; hydroxyl groups; nitro groups; cyano groups; amino groups; dimethylamino groups, diethylamino groups, dibenzylamino groups, etc. substituted amino groups; carboxyl groups; alkoxycarbonyl groups such as ethoxycarbonyl groups; aryloxycarbonyl groups such as phenyloxycarbonyl groups; acyloxy groups such as acetoxy groups and benzoyloxy groups; acyl groups such as acetyl groups and benzoyl groups; carbamoyl substituent aminocarbonyl groups such as dimethylaminocarbonyl group, phenylaminocarbonyl group; arylalkoxy groups such as benzyloxy group and phenethyloxy group, aryl group, heterocyclic group, and heterocyclic group.

Specific examples of the coupler residue represented by Cp in general formula [I] or general formula [II] are shown below, but the present invention is not limited thereto.

Below are blank spaces - 12, 9 Below are blank spaces: Specific examples of groups having an azo group bonded to the coupler residue Cp in general formula [1] or general formula [n] are shown below. It is not limited.

Margin below - 11shi (I-2) (I-3) (I-4) (I-8) (I -11) 3r (I-18) σ-7- Below margin 7k; ν (I [-2) (II-3) (n-5) (It-7) (II-8) (II-9) (II-10) Below blank space-2> The general formula [II] of the present invention The bisazo compound can be synthesized by a known method.

Synthesis Example 1 Disperse 0.01 mol of compound [II in 10-hydrochloric acid and 20-mol water, and add 0.02 mol of sodium nitrite while keeping the temperature below 5°C.
A solution prepared by dissolving 5 mol of water in 5 te of water was added dropwise. After stirring for another hour at the same temperature, insoluble matter was removed by filtration, and a solution of 4.6 g of ammonium hexafluorophosphate dissolved in 501Q of water was added to the filtrate. The precipitated tetrazonium salt was collected by filtration, and N
, dissolved in 100 d of N-dimethylformamide (DMF). While maintaining the temperature at 5°C, 0.02 mol of compound (II) was added to DMF 200. A solution of p was added dropwise.

While continuing to maintain the temperature below 5°C, add 0.0% of triethanolamine. ．． 04 mole to D MF 30. The solution dissolved in Q was added dropwise, and the mixture was stirred at 5° C. or lower for 1 hour and at room temperature for 4 hours.

After the reaction, the precipitated crystals were collected by filtration, washed with DMF, washed with water, and dried.
0.0064 mol of the compound (m) according to the present invention was obtained.

This compound (III) was confirmed to be a compound according to the present invention based on elemental analysis values. The yield was 64%, and the elemental analysis values were as follows.

HN Calculated value (%) 69.10 3.54 12.40 Actual value (%) 69.01 3.75 12.32 or less margin 1121 Synthesis example 2 Compound (1') 0.02 mol, and water While stirring 0.05 mol of sodium oxide powder with dimethyl sulfoxide 21 under 20°C conditions, a solution of 0.01 mol of tetrazonium borohydrofluoride (II') dissolved in methyl sulfoxide 31 was added dropwise. , and keep it as it is for 3 hours. After the reaction, 0.04 mol of acetic acid was added to the reaction solution, the precipitated bisazo compound was collected by filtration, and then diluted with dilute acetic acid,
After washing with water, methanol, and tetrahydrofuran, the product was dried to obtain a compound (■') according to the present invention. This compound (
2') was confirmed to be a compound according to the present invention based on elemental analysis values. The yield was 55%, and the elemental analysis values were as follows.

HN Calculated value (%)? 3.64 3.18 15.91 Actual value (%) 73.52 3.45 Below 15.70 Nadomari Synthesis Example 3 Compound (1') o, oi mol and 3001 mol of naphthol A are dissolved in 3 ml of dimethyl sulfoxide. .

Compound (I) was added while keeping this solution at a temperature of 20-23°C.
[') After adding a solution of tetrazonium borohydrofluoride (■') obtained by diazotizing 0.01 mol in dimethyl sulfoxide 2y, 0.02 mol of sodium acetate was added while stirring. A solution dissolved in 201 g of water was added dropwise, and the mixture was stirred for 3 hours.

The deposited precipitate was separated by filtration, washed with dimethyl sulfoxide, dilute acetic acid, water, methanol, and tetrahydrofuran, dried, and then isolated to obtain a compound (■'') according to the present invention.

This compound (■'') was confirmed to be a compound according to the present invention based on elemental analysis values and absorption spectra.The yield was 4.
0%, and the elemental analysis values were as follows.

HN Calculated value (%) 71.33 3.57 16.64 Actual value (%) 71.14 3.81 16.45z
z o 0 Other compounds of the present invention can also be strained in the same manner as in the above synthesis example.

The bisazo compound according to the present invention has excellent light conductivity, and the child photographic photoreceptor of the present invention can be produced by dispersing the bisazo compound in a binder and providing it on a conductive support. The bisazo compound according to the present invention takes advantage of its excellent carrier ability, uses it as a carrier generating substance, and uses a carrier transporting substance that can effectively act in combination with this, so-called functional separation type photosensitizer. It can be a body. The machine-separated type photoreceptor may be a mixed and dispersed type of both of the above substances, but a laminated type photoreceptor in which a carrier generation layer and a carrier transport layer containing a carrier generation substance made of a bisazo compound according to the present invention are laminated. It is more preferable to take

In the case of a photosensitive layer with a laminated structure, the carrier generation layer absorbs most of the incident light and generates a large amount of charge generation carriers, and also recombines and captures the generated charge carriers.
It is preferable to make the layer as thin as possible within a range of thickness sufficient to generate photocarriers in order to inject them into the carrier transport layer without being deactivated by traps.

Further, the carrier transport layer is electrically connected to the carrier generation layer described above, and has a function of transporting charge carriers injected from the charge generation layer to the surface in the presence of an electric field.

In addition, in a functionally separated photoreceptor with a single layer structure, photocarriers are generated and transported in a single layer, and the carrier generation substance and the carrier transport substance are electrically bonded within the layer, and/or the carrier generation substance and the carrier transport substance are electrically bonded within the layer. Substances also contribute to carrier transport.

Further, the carrier generation layer may contain both the carrier generation substance and part of the carrier transport substance. In either layer structure, a protective layer may be provided on the photosensitive layer, and a subbing layer (intermediate layer) having a barrier function and adhesive properties may be provided between the support and the photosensitive layer.

Examples of binder resins that can be used for the photosensitive layer, protective layer, and subbing layer include polystyrene, polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, and phenol. resin, polyester resin, alkyd resin, polycarbonate resin,
Examples include addition polymer resins such as silicone resins and melamine resins, polyaddition resins, polycondensation resins, and copolymer resins containing two or more repeating units of these resins. In addition to these insulating resins, polymeric organic semiconductors such as poly(1J-N-vinylcarbazole) may be used.

Furthermore, organic amines can be added to the photosensitive layer for the purpose of improving the carrier generation function of the carrier generation substance.
In particular, it is preferable to add a secondary amine. The amount of the organic amine added is 1 times or less, preferably 0.2 times to 0.0 times the amount of the carrier generating substance.
The number of moles is preferably in the range of 0.005 times.

Further, in the photosensitive layer, antioxidants such as hindered phenols, hindered amines, para-phenylene diamines, hydroquinones, and organic phosphorus compounds may be added for the purpose of preventing ozone deterioration.

These compounds are known as antioxidants for rubber, plastics, oils and fats, and are easily available commercially.

These antioxidants may be added to any of the carrier generation layer, carrier transport layer, or protective layer, but are preferably added to the carrier transport layer.

In that case, the amount of antioxidant added is 10 parts of the carrier transport substance.
0.1 to 100 parts by weight, preferably 1 part by weight
~50 parts by weight, particularly preferably 5 to 25 parts by weight.

Next, the conductive support supporting the photosensitive layer may be a metal plate made of aluminum, nickel, etc., a metal drum, or a metal foil laminated, or made of aluminum, tin oxide, etc.
A plastic film coated with indium oxide or the like, or a paper or plastic film coated with a conductive substance, or a drum can be used.

In the present invention, the carrier generation layer is typically formed by applying a dispersion of the bisazo compound according to the present invention described above in a suitable dispersion medium alone or together with a suitable binder resin, for example, by dip coating, spray coating, blade coating, or roll coating. It can be provided by a method of coating the support, subbing layer, or carrier transport layer by coating and drying.

Further, for dispersing the bisazo compound according to the present invention, a ball mill, a homomixer, a sand mill, an ultrasonic disperser, an attritor, etc. are used.

Examples of the dispersion medium for the bisazo compound according to the present invention include hydrocarbons such as hexane, benzene, toluene, and xylene; methylene chloride, 1,2-dichloroethane, and s
Halogenated hydrocarbons such as ym-tetrachloroethane, 1゜1.2-trichloroethane and chloroform; Ketones such as acetone, methyl ethyl ketone and cyclohexanone; Esters such as ethyl acetate and butyl acetate; methanol, ethanol, propatool, Alcohols and derivatives thereof such as butanol, cyclohexanol, heptatool, ethylene glycol, methyl cellosolve, ethyl cellosolve, acetic acid cellosolve; tetrahydrofuran, 1.
Ethers such as 4-dioxane, furan, furfural, etc.
Acetals; Amines such as pyridine, butylamine, diethylamine, ethylenediamine, and isopropanolamine; N.

One or more of nitrogen compounds such as amides such as N-dimethylformamide, oil fatty acids thereof and phenols, sulfur and phosphorus compounds such as carbon disulfide and triethyl phosphate can be used.

When the photoreceptor of the present invention has a laminated structure, the weight ratio of binder:carrier generating substance:carrier transporting substance in the carrier generating layer is preferably 0-100:1-500:O-500.

If the content of the carrier-generating substance is less than this, the sensitivity will be low and the residual potential will increase, and if it is more than this, the dark decay and acceptance potential will decrease.

The thickness of the carrier generation layer formed as described above is
Preferably 0.01 to 10 μm1, particularly preferably 0.1 to 10 μm1
It is 5 μm.

In the present invention, the carrier transport layer can be formed by applying and drying a carrier transport substance dissolved and dispersed in a suitable dispersion medium alone or together with the above-mentioned binder resin. As the dispersion medium used, the dispersion medium used in dispersing the carrier-generating substance can be used.

Carrier transport substances that can be used in the present invention include:
Although not particularly limited, examples include oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidasilone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds,
Pyrazoline compounds, amine derivatives, oxacilone derivatives, benzothiazole derivatives, benzimidazole derivatives, quinaprine derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives,
These include poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, and the like.

The carrier transport substance used in the present invention is preferably one that has an excellent ability to transport holes generated during light irradiation to the support side and is suitable for combination with the bisazo compound according to the present invention. Preferred transport substances are the following general formulas (A) and (B):
and (C).

General formula (A) Ar! R In the formula, Ar1, Ar, and Ar4 each represent a substituted or unsubstituted aryl group, Ar represents a substituted or unsubstituted arylene group, and R is a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or Represents an unsubstituted aryl group.

Specific examples of such compounds are described in detail on pages 3 to 4 of the specification of JP-A-58-65440 and pages 3-6 of the specification of JP-A-58-198043.

General formula (B) In the formula, R8 is a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic group, and R1 is a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. For details, refer to JP-A-58-13464.
No. 2 and No. 58-166354 specification.

General formula (C) R9 In the formula, R4 is a substituted or unsubstituted aryl group, and R
3 is a hydrogen atom, a halogen atom, a hydroxy group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted amino group, and Rs
represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic group. Synthesis methods for these compounds and exemplified compounds thereof are described in detail in Japanese Patent Publication No. 148750/1982, which can be incorporated into the present invention.

Other preferable carrier transport materials used in the present invention include Japanese Patent Publications Nos. 57-67940 and 59-152.
Examples include hydrazone compounds described in Japanese Patent No. 52 and No. 57-101844, respectively.

In the present invention, the amount of the carrier transport substance added is preferably 20 to 200 parts by weight, particularly preferably 30 to 150 parts by weight, based on 100 parts by weight of the binder resin in the carrier transport layer.

The thickness of the carrier transport layer to be formed is preferably 5 to 5.
The thickness is preferably 0 μm, particularly preferably 5 to 30 μm.

Further, in the case of a monolayer functionally separated electrophotographic photoreceptor using the bisazo compound according to the present invention, the ratio of binder: bisazo compound: carrier transport substance is θ~100:1~50.
0:0 to 500 is preferable, and the thickness of the photosensitive layer to be formed is preferably 5 to 50 μm, particularly preferably 5 to 30 μm.
It is.

In the present invention, the carrier generation layer may contain one or more electron-accepting substances for the purpose of improving sensitivity, reducing residual potential or fatigue during repeated use, etc. The addition ratio of the electron-accepting substance is a weight ratio of bisazo compound according to the present invention:electron-accepting substance=100:0.
01 to 200 is preferable, more preferably 100:
It is 0.1-100.

The electron-accepting substance may be added to the carrier transport layer, and in this case, the proportion of the electron-accepting substance added is a weight ratio of total carrier-transporting substance:electron-accepting substance=100:0.01.
~100 is preferred, more preferably 100:0.1~
It is 50.

In addition, the photoreceptor of the present invention may also contain, if necessary, an ultraviolet absorber, an antioxidant, etc. for the purpose of protecting the photosensitive layer, and may also contain a dye for color sensitivity correction.

[Effects of the Invention] As explained in detail above, according to the present invention, by containing a specific bisazo compound that can be combined with a wide range of carrier transport substances and has excellent carrier generation ability,
It is possible to provide an electrophotographic photoreceptor that has high sensitivity and good color sensitivity, has little variation in sensitivity, chargeability, and residual potential even after repeated use, and has extremely excellent durability. Further, the photoreceptor of the present invention is suitable not only for electrophotographic plain paper copying machines but also as a photoreceptor for printers such as laser printers and LED printers.

Furthermore, the bisazo compound according to the present invention can also be effectively used in electroluminescent devices.

[Examples] Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto.

Example 1 Vinyl chloride-vinyl acetate-
Maleic anhydride copolymer “S-LEC MF-10J
(manufactured by Tanezu Kagaku Co., Ltd.) with a thickness of 0.05 g, and on top of that, t-2 g of the following bisazo compound (A-2) as a carrier generating substance (CGM) and polyvinyl butyral resin "S-LEC BH- 3J (manufactured by Tsukimizu Kagaku Kogyo Co., Ltd.) was added to 110 d of tetrahydrofuran and dispersed in a ball mill for 12 hours. This dispersion was applied to a dry film thickness of 0.5 μm to form a carrier generation layer. Furthermore, as a carrier transport layer, a solution prepared by dissolving 6 g of a carrier transport substance (K-1) having the following structural formula and 10 g of a polycarbonate resin "Nipilon Z-200J (manufactured by Mitsubishi Gas Chemical Co., Ltd.) in 80 d of 1,2-dichloroethane was coated so that the film thickness after drying was 18 μm to form a carrier transport layer to prepare photoreceptor sample No. 1 of the present invention.Then, the carrier-generating substance and the carrier-transporting substance are shown in Table 1. Photoreceptor samples Nos. 2 to 19 were prepared in the same manner except that the following changes were made.

The photoconductor obtained in the above manner was transferred to
The following characteristics were evaluated using a PA-8100 electrostatic copying paper tester. That is, after being charged for 5 seconds with a charging voltage of -6KV, it was left to stand for 5 seconds, and then the illuminance on the photoreceptor surface was increased to 3KV.
A halogen lamp light was irradiated at 5 lux·sec to determine the surface potential (V) and the exposure amount used to attenuate the surface potential by half (half-reduction exposure amount) El/2. The results are shown in Table 1.

The following margin Q Q O: 0: ω's Ku'S -〇< Kukuku = = Q 0 Kuku [2G' Toku Kuni-I K-2 to -3 to -4 to -5 to -6 ni-8 Below margin-, Nishi Comparative Example 1 The following bisazo compound (G-1) was used as a carrier generating substance.
Comparative photoreceptor sample No. 20 was prepared in the same manner as in Example 1, except that .

(G-1) This comparative photoreceptor was measured in the same manner as in Example 1, and the results shown in Table 1 were obtained.

As is clear from the results in Table 1 and above, the photoreceptor of the present invention has extremely superior sensitivity compared to the comparative photoreceptor. It is something.

Example 2 A 0.0-thick film made of vinyl chloride-vinyl acetate-maleic anhydride copolymer [S-LEC MF-10J (manufactured by Tsukisui Kagaku Co., Ltd.)] was coated on the surface of an aluminum drum with a diameter of 60 mm.
A 5 μm intermediate layer was provided, and on top of that, 2 g of CGMA-1 and polyvinyl butyral resin “S-LEC BH-3J” were added.
(manufactured by Tsukimizu Kagaku Kogyo Co., Ltd.) 2g and 10g of tetrahydrofuran
A dispersion liquid was mixed at 0 mJ2 and dispersed for 24 hours using a ball mill dispersion machine, and then applied to a film thickness of 06 μm after drying to form a carrier generation layer.

Furthermore, on top of this, 30 g of the carrier transport substance (K-1)
and polycarbonate resin "Nipiron Z-200J (manufactured by Mitsubishi Gas Chemical Co., Ltd.) 50g and 1,2-dichloroethane 4
A photoreceptor sample 21 was prepared by dissolving the photoreceptor in 00d and applying it to a film thickness of 18 μm after drying to form a carrier transport layer.

When the photoreceptor sample 21 prepared in this manner was attached to a modified electrophotographic copying machine rU-Bix 1550MRJ (manufactured by Konica) and the image was copied, a copy image with high contrast, faithful to the original, and clear was obtained. Obtained. In addition, we took this machine to an environmental test room under high temperature and high humidity (33℃; 80%) and tested its repeated durability.
Even after 50,000 repetitions, a clear copy image with high contrast was obtained.

Comparative Example 2 A drum-shaped comparative photoreceptor sample was prepared in the same manner as in Example 2, except that the carrier-generating substance in Sample No. 11 of Example 1 was replaced with a bisazo compound represented by the following structural formula (G-2). No. 22 was created and the copied images were evaluated in the same manner as in Example 2. Regarding the durability of repeated printing under high temperature and high humidity conditions, the contrast decreased from around 30,000 times and only images with a lot of fog were obtained. I couldn't.
) [-The following system 1 white ■ (G-2) Example 3 Vinyl chloride-vinyl acetate-
Maleic anhydride copolymer, [S-LEC M F-10
J (manufactured by Tanezu Kagaku Co., Ltd.) with a thickness of 0.05 μm! A solution obtained by dissolving 6 g of the following structural formula (K-11) as a carrier transport substance and 10 g of polycarbonate resin "Panlite L-1250J" in 1,2-dichloroethane 801Q was placed on top of it, and the film thickness after drying was 15 μm. A carrier transport layer was formed.

(K-11) Furthermore, carrier generating substances A-5, A-8゜A-1
0.0, 1.5 g of the above carrier transport material, and 2 g of polycarbonate resin "Panlite L-1250J".
In addition to 2-dichloroethane 301Q, a solution dispersed in a ball mill for 24 hours was applied, and a carrier generation layer having a thickness of 4 μm after drying was provided to form a photoreceptor sample No. 2 of the present invention.
3 to 25 were created.

The charging polarity of each of these photoreceptors is positively charged.
The measurements were carried out in the same manner as in Example 1 except for binding, and the results shown in Table 2 were obtained.

Table 2 Example 4 Other than changing the carrier-generating substance used in the carrier-generating layer and the carrier-transporting substance used in the carrier-transporting layer as shown in Table 8, In the same manner as in Example 1, photoreceptor sample No.
26-43 were created.

The obtained photoreceptor sample was prepared using a modified printer LP-3010 (manufactured by Konica) equipped with an LED light source, and the unexposed part potential was . , the exposed part potential vL was determined and the sensitivity was evaluated. The results are shown in Table 3.

Comparative Example 3 Example 4 except that the compounds used in the carrier generation layer and the compounds used in the carrier transport layer were changed as shown in Table 3.
Photoreceptor sample No. 44 was prepared in the same manner as above.

The sensitivity of the obtained photoreceptor was evaluated in the same manner as in Example 4. The results are shown in Table 3.

Below is the blank space - Table 3 00-1 shows the compounds used in Comparative Example 1 -12 -13 -14 -15 -16 -17 -18 -20 Above Examples and Comparative Examples As is clear from the results, the photoreceptor samples of the present invention were found to be significantly superior to the comparative photoreceptor samples in terms of stability, sensitivity, durability, compatibility with a wide range of carrier transport substances, etc. .

Claims (1)

[Claims] The following general formula [I] or general formula [II] is formed on a conductive support.
An electrophotographic photoreceptor comprising a photosensitive layer containing a bisazo compound represented by: General formula [I] ▲ Numerical formulas, chemical formulas, tables, etc. Each represents a substituent, m^1 and m^4 each represent an integer of 0 to 4, and m^2 and m^3 each represent an integer of 0 to 2. ] General formula [II] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [In the formula, Cp each independently represents a coupler residue having a phenolic hydroxyl group, R^1 and R^4 each represent a substituent, m ^1 and m^4 each represent an integer from 0 to 4. ]