JPH04146445A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To offer an electrophotographic sensitive body containing azo compound functioning effectively as a carrier generating material by forming combination even with a wide range carrier transportation material. CONSTITUTION:This electrophotographic sensitive body is provided with a photosensitive layer containing the azo compound represented in general equation [I] on a conductive supporting body. Two to four N=N-Cp are contained in general equation [I], and they can be coupled with any positions where R<1>, R<2>, R<3>, or R<4> can be substituted. Cp represents a coupler residual group provided with a phenol hydroxyl group, however, the phenol hydroxyl group is a hydroxyl group substituted to an aromatic hydrocarbon circle, and a hydrocarbon circle or a hetero-circle can be further condensated in the aromatic hydrocarbon circle. It is desirable to form a laminate type photosensitive body in which a carrier generating layer containing the carrier generating material consisting of the azo compound relating to this invention and a carrier transportation layer are laminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor having a photosensitive layer containing an azo 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 the drawbacks of these inorganic grade 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-dolinitro-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. As a carrier generating substance having a carrier generating function in such a functionally separated photoreceptor,
Many compounds such as organic dyes and organic pigments have been proposed. For example, JP-A-54-22834, JP-A-55-7305
No. 7, No. 55-117151, No. 56-46237, etc., describe electrophotographic photoreceptors containing an azo compound, particularly a bisazo compound, in the photosensitive layer.

[Problems to be Solved by the Invention] However, none of the azo compounds described in the above publications are 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 azo compound having excellent carrier generation ability.

Another object of the present invention is to provide 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 an azo 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 discovered that a specific azo compound can act as an excellent active ingredient of an electrophotographic photoreceptor, This completes the present invention. That is, the above object of the present invention is achieved by an electrophotographic photoreceptor characterized by having a photosensitive layer containing an azo compound represented by the following general formula [I] on a conductive support.

General formula [Ico (in the formula, Cp each independently represents a coupler residue having a phenolic hydroxyl group, R', R2°R1 and R4 each represent a substituent, m', m'').

ml and m4 each represent an integer from 0 to 4, and n is 2
Represents an integer from ~4. ) The present invention will be explained in more detail below.

In the general formula [I], 2 to 4 -N=N-Cp are contained, and R
I can be attached at any position where R11, R1 or R4 can be substituted. However, -N=N-m", m', m" depending on the number of Cp and the substitution position.

It is assumed that the value of m4 changes as appropriate. Further, in the present invention, when m'-m' is each 2 or more, m1 RIs,
m1 RIs and m3 R''Sm' R4 may be the same or different.

When the number of -N=N-Cp in general formula [I] is 2 or more, n
The Cp's 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. The heterocycles may be fused.

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

(In the formula, Y and Y 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 alphkidicarbonyl group, an aryloxycarbonyl group, a carbamoyl group, a hydrazinocarbonyl group, an acyl group, or an acylamino group. ) General formula [ml (wherein, Y 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, This represents an aryloxycarbonyl group or an acyl group, and 2 represents a divalent group that is condensed with a benzene ring to form an aromatic hydrocarbon ring or a heterocycle.) General formula [ ] (In the formula R □ and R3 each independently represent a hydrogen atom, a lower alkyl group, an aryl group, or a heterocyclic group, and R□
and R2 may be bonded to each other to form a ring. Z has the same meaning as in the general formula [I1]. ) General formula [V] (wherein, R, , R, and Z are each represented by the above-mentioned general formula [V]
IV]. ) (In the formula, R1 and R4 each independently 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 R and R4 are bonded to each other to form a ring. Z may have the same meaning as in the general formula [IIT].) General formula [■] (wherein, R1 and R1 each have the same meaning as in the general formula [IV
] or has the same meaning as in general formula [VI]. ) General formula [■] (In the formula, R4 and Z have the same meanings as in the above general formula [ml or [rV], respectively.) General formula [IX
] R1 (In the formula, R8 represents an alkyl group, an unsaturated alkyl group, or an aryl group.) General formula [X] [In the formula, Rs, Rt, R*, and R1 each represent a hydrogen atom, a halogen atom, or an alkyl group. , represents a vinyl group, a substituted amino group or an aryl group, and R6 is also CR
t. (However, R1° represents an alkyl group, an aryl group, a heterocyclic group, a vinyl group, an amino group, or an alkoxy group.)
shows. ] General formula may have.

In each of the general formulas [n] to [X], examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and examples of the substituted or unsubstituted alkyl group include a methyl group, an ethyl group, n-propyl group, n-
Butyl group, isobutyl group, tert-butyl group, n-hexyl group, n-octyl group, benzyl group, p-methylbenzyl group, p-chlorobenzyl group, 2-phenylethyl group, 1-naphthylmethyl group, 2- Examples include naphthylmethyl group, allyl group, 2-hydroxyethyl group, 2-methoxyethyl group, 3-morpholinopropyl group, 2-diethylaminoethyl group, and 3-carbazolylmethyl group. R
The lower alkyl group represented by 1 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, phenanthryl 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, dimethylaminocarbonyl group basis,
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., which 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 combining Ro and R8 with each other include a cyclohexylidene group, an indolyl group, a fluorenyl group, and a pentamethylene group.

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

Q in the general formula [X I ] represents a divalent aromatic hydrocarbon group which may have a substituent 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, and a 1,2-anthraquinonylene group. , 9.10-phenanthrylene group, and other divalent condensed polycyclic aromatic hydrocarbon groups.

In addition, examples of the divalent heterocyclic group include 34-pyrazolediyl group, 2,3-pyridinediyl group, 3,4-pyridinediyl group, 4,5-pyrimidinediyl group, 6,7
Examples include divalent heterocyclic groups such as -indazolediyl group, 5,6-benzimidazolediyl group, and 5,6-chiralindiyl group.

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 didiano group amino group; dimethylamino group, diethylamino group Substituted amino groups, such as dibenzylamino groups; halogen atoms, such as fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms; carboxyl groups; alkoxycarbonyl groups, such as ethoxycarbonyl groups; acyl groups, such as carbamoyl groups, acetyl groups, benzoyl groups, etc. groups; aryloxy groups such as phenoxy groups; arylalkoxy groups such as benzyloxy groups; and aryloxycarbonyl groups such as phenyloxycarbonyl groups. Among these, an alkyl group, an alkoxy group, 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 preferable.

In the present invention, the coupler residue C-p has the general formula [V]
, [VI] or [XI] is particularly preferred.

Substituents represented by R1 to R4 in general formula [I] include alkyl groups such as methyl, ethyl, and butyl; halogen atoms such as fluorine, chlorine, bromine, and iodine; methoxy, ethoxy, Alkoxy groups such as butoxy groups; aryloxy groups such as phenoxy groups; hydroxyl groups; nitro and cyano groups; amino groups; substituted amino groups such as dimethylamino, diethylamino, and dibenzylamino groups; carboxyl groups; ethoxycarbonyl groups, etc. Alkoxycarbonyl 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, dimethylaminocarbonyl group, phenylaminocarbonyl group, etc. Substituted aminocarbonyl group; Examples include 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] are shown below, but the present invention is not limited thereto.

Specific examples of the group having an azo group that binds to the coupler residue Cp in the general formula [I] are shown below, but the present invention is not limited by these (I-1) N=N- (I- 5) (I-10) CI-13) <1-17) <1-19) Lihe-Pe- The azo compound represented by the general formula [II of the present invention can be synthesized by a known method. .

Synthesis Example 1 0.01 mol of compound [I] was dispersed in 10 d of hydrochloric acid and 201 Q of water, and 0.0 mol of sodium nitrite was added while keeping the temperature below 5°C.
A solution of 2 moles dissolved in 5 volumes 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
, N-dimethylformamide (DMF) 100. Dissolved in Q. While maintaining the temperature at 5°C, a solution of 0.02 mol of compound (II) dissolved in 200 d of DMF was added dropwise.

Subsequently, a solution of 0.04 mol of triethanolamine dissolved in DMF 30d was added dropwise while keeping the temperature below 5°C, and the mixture was stirred at below 5°C 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 to obtain o, ooso moles of the compound (m) according to the present invention. This compound (I[) was confirmed to be a compound according to the present invention based on elemental analysis values. The yield was 80%, and the elemental analysis values were as follows.

C Calculated value (%) 72.16 3.49 8.15 Actual value (%) 3.65 Below i'P3 ρ- Synthesis Example 2 0.02 mol of compound (1') and 0.02 mol of sodium hydroxide powder. A solution of 0.01 mol of tetrazonium borohydrofluoride (■') dissolved in 31 dimethyl sulfoxide was added dropwise to 0.05 mol of dimethyl sulfoxide and 22 mol of dimethyl sulfoxide while stirring at 20°C, and the solution was left for 3 hours. Hold. After the reaction, 0.04 mol of acetic acid was added to the reaction solution, and the precipitated azo compound was collected by filtration, which was then washed with dilute acetic acid, water, methanol, and tetrahydrofuran, and then dried to obtain the compound (■') according to the present invention. Ta. This compound (■′)
Based on the elemental analysis values, compound No. 2 was confirmed to be a compound according to the present invention. The yield was 74%, and the elemental analysis values were as follows.

HN Calculated value (%) 76.19 3.17 11.11 Actual value (%) 76.03 3.44 11.08 Synthesis example 3 0.01 mole of compound (1') and 3001 mole of naphthol A were mixed with dimethyl sulfoxide 3! dissolve in

The compound (n
) After adding a solution of tetrazonium borohydrofluoride (■') obtained by diazotizing 0.01 mol in dimethyl sulfoxide 21, 0.02 mol of sodium acetate was added to water with stirring. A solution dissolved in 201 g 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 and absorption spectrum. Yield is 3
8%, and the elemental analysis values were as follows.

CHN Calculated value (%) 76.75 3.55 9.95 Actual value (%) 76.71 3.80 9.89/-m-
〜＼ Other compounds of the present invention can also be produced in the same manner as in the above synthesis example.

The azo compound according to the present invention has excellent photoconductivity,
The electrophotographic photoreceptor of the present invention can be manufactured by providing a photosensitive layer in which the photoreceptor is dispersed in a binder on a conductive support. The azo compound according to the present invention utilizes its excellent carrier generation ability and is used as a carrier generation substance, and by using a carrier transport substance that can effectively act in combination with this, a so-called functionally separated type of azo compound can be obtained. It can be a photoreceptor. The functionally separated photoreceptor may be a mixed and dispersed type of both of the above substances, but it may be a laminate type in which a carrier generation layer containing a carrier generation substance made of an azo compound according to the present invention and a carrier transport layer are laminated. It is more preferable to use a photoreceptor.

In the case of a photosensitive layer with a laminated structure, most of the incident light is absorbed by the charge generation layer, generating many charge generation carriers, and the generated charge carriers are deactivated by recombination or trapping. It is preferable to make the layer as thin as possible within a range of thickness sufficient to generate photocarriers for injection into the carrier transport layer.

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 a 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-N-vinylcarbazole may also 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 azo 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. In addition, for dispersing the azo compound according to the present invention, a ball mill,
A homomixer, sand mill, ultrasonic disperser, attritor, etc. are used.

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

One or more of nitrogen compounds such as amides such as N-dimethylformamide, other fatty acids and phenols, and 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 O~100:1~5'00: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 001-10 μm1, particularly preferably 0.1-10 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 also suitable for combination with the above-mentioned Ab compound according to the present invention. Preferred transport substances include those represented by the following general formulas (A), (B) and (C).

General formula (A) In the formula, Ar, Ar, and Ar4 each represent a substituted or unsubstituted aryl group, Ara represents a substituted or unsubstituted arylene group, and R is a hydrogen atom or a substituted or unsubstituted alkyl group. represents a group or a substituted or 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 R2 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.

General formula (C) In the formula, R1 is a substituted or unsubstituted aryl group, and R
2 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 Ra
represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic group. For synthetic methods of these compounds and their exemplified compounds, see Japanese Patent Publication No. 57-148750.
It is described in detail in the specification of the publication, and 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.
0 μm1, particularly preferably 5 to 30 μm.

Further, in the case of a monolayer functionally separated electrophotographic photoreceptor using the azo compound according to the present invention, the ratio of binder:azo compound:carrier transport substance is 0 to 1o.

:1~500:O~500 is preferable, and the thickness of the photosensitive layer to be formed is preferably 5~50μm, particularly preferably 5μm.
~30 μm.

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: azo compound according to the present invention: electron-accepting substance = 100: 0.01
-200 is preferable, and 100:0 is more preferable.
It is 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, the present invention provides high sensitivity and color sensitivity by containing a specific azo 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 having excellent durability, with little change in sensitivity, chargeability, and residual potential even after repeated use. 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 azo 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 μm, on which 2 g of the following azo compound (A-2) as a carrier generating substance (CGM) and polyvinyl butyral resin “S-LEC BH-3J ( Manufactured by Building Block Chemical Industry Co., Ltd.)
2g and 110.0g of tetrahydrofuran. fi and was dispersed in a ball mill for 12 hours. This dispersion was applied to a dry film thickness of 05 μm to form a carrier generation layer, and on top of this, 6 g of a carrier transport substance (K-1) having the following structural formula and a polycarbonate resin were applied as a carrier transport layer. “Kneepilon Z-2004 (manufactured by Mitsubishi Gas Chemical Co., Ltd.) 1
A carrier transport layer was formed by dissolving a solution of 0 g in 80 mj2 of 1,2-dichloroethane so that the film thickness after drying was 18 μm, and photoreceptor sample No. 1 of the present invention was prepared. Next, photoreceptor samples Nos. 2 to 19 were prepared in the same manner except that the carrier-generating substance and the carrier-transporting substance were changed as shown in Table 1.

The photoreceptor obtained as described above was subjected to the following characteristic evaluations using an electrostatic copying paper tester EPA-8100 manufactured by Rodenki Seisakusho Co., Ltd. That is, after charging with a charging voltage of -6 KV for 5 seconds, leaving it for 5 seconds, and then irradiating it with halogen lamp light so that the illumination intensity on the photoreceptor surface is 35 lux · seconds, the surface potential (Vo) and the surface potential are halved. The exposure amount (half-reduced exposure amount) El/2 used for attenuation was determined.

The results are shown in Table 1.

・−ri Below - Margin +] lecture, te- One to one yen size Kubek< Ku Engineering Engineering Ku Ku Engineering: I:= Engineering u Q Q.

-17 -1 -2 -3 -4 -5 -8 -10 Comparative Example 1 The following bisazo compound (G -1
) Comparative photoreceptor sample No. 20 was prepared in the same manner as in Example 1, except that photoreceptor sample No. 20 was used.

(G-1) Regarding this comparative photoreceptor, measurements were performed in the same manner as in Example 1, and the results shown in Table 1 were obtained.

As is clear from the results shown in Table 1 below, the photoreceptor of the present invention is extremely superior in sensitivity than the comparative photoreceptor.

Example 2 Vinyl chloride-vinyl acetate-maleic anhydride copolymer "S-LEC M" was coated on the surface of an aluminum drum with a diameter of 60 mm.
Made of F-10J (manufactured by Tsukimizu Kagaku Co., Ltd.) with a thickness of 0.05
A μm-thick intermediate layer is provided, and 2 g of CGMA-1 and polyvinyl butyral resin “S-LEC BH-3J (
2g (manufactured by Miki Kagaku Kogyo Co., Ltd.) and 100g of tetrahydrofuran.
d and dispersed for 24 hours using a ball mill dispersion machine was applied to form a carrier generation layer so that the film thickness after drying was 0.6 μm.

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
001fi and coated to form a carrier transport layer so that the film thickness after drying becomes 18 μm.
made.

The photoreceptor sample 21 prepared in this manner was transferred to an electrophotographic copying machine rU-Bix 1550M RJ (K on
When the image was copied using a modified machine (manufactured by ICA), a copy image with high contrast, faithful to the original, and clear was obtained. In addition, we took this machine into an environmental test room under high temperature and high humidity conditions (33°C; 80%) to test its durability over repeated use, and found that it was able to produce clear copied images with high contrast even after so many repetitions. It was done.

Comparative Example 2 A drum-shaped comparative photoreceptor sample No. 2 was prepared in the same manner as in Example 2, except that the carrier-generating substance in Sample No. 1 of Example 1 was replaced with an azo compound represented by the following structural formula (G-2). , 22 was prepared, and the copied images were evaluated in the same manner as in Example 2. Regarding the durability of repetition under high temperature and high humidity conditions, the contrast deteriorated from around 3Q, 000 times, and the image produced a lot of fog. 5 CG-2) Example 3 Vinyl chloride-vinyl acetate-
Maleic anhydride copolymer, “S-LEC MF-10J
(manufactured by Tsukimizu Kagaku Co., Ltd.) with a thickness of 0.05 μm, and on top of that, as a carrier transport substance, the following structural formula (
A carrier transport layer was formed by applying a solution prepared by dissolving 6 g of K-11) and 10 g of polycarbonate resin "Panlite L-1250J" in 80 g of 1,2-dichloroethane so that the film thickness after drying was 15 μm. did.

(K-11) Furthermore, carrier generating substance A-5A-8 or A-1 is added thereto.
02g, 1.5g of the above carrier transport substance and polycarbonate resin [Panlite L-1250J2g 1.2g]
- In addition, the dispersion liquid was applied with a ball mill for 24 hours, and the film thickness after drying was 4 μm.
Photoreceptor sample N of the present invention was provided with a carrier generation layer of
o, 23-25 were created.

Each of these photoreceptors was measured in the same manner as in Example 1, except that the charging polarity was changed to positive, and the results shown in Table 2 were obtained.

m--: space below 'h--j) Table 2 Example 4 The carrier-generating substance used in the carrier-generating layer and the carrier-transporting substance used in the carrier-transporting layer were changed as shown in Table 3. Photoreceptor sample No. 2 was prepared in the same manner as 1.
6 to 43 were created.

The obtained photoreceptor sample was processed using a modified printer LP-3010 (manufactured by Konica) equipped with an LED light source.
The potential of the unexposed area (v) I- and the potential of the exposed area (1) were determined to evaluate the sensitivity. 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.

Table 3 * G-1 shows the compounds used in Comparative Example 1 -12 to -13 to -14 to -15 to -16 to -17 to -18 to -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)

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