JPH04128766A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance sensitivity and to decrease residual potential as well as to improve the durability at the time of repetitive use by incorporating a photosensitive layer contg. specific azo compds. on a conductive base. CONSTITUTION:The photosensitive layer contg. the azo compds. expressed by formula I, formula II, etc., is provided on the conductive base body. In the formula I, Cp respectively independently denotes a residual coupler group having a phenolic hydroxyl group; R<1> to R<4> respectively denotes a substituent; m<1>, m<4> respectively denote an integer from 0 to 4; m<2>, m<3> respectively denote an integer from 0 to 2; (n) denotes an integer from 2 to 4. In the formula II, Cp respectively independently denotes a residual coupler group having a phenolic hydroxyl group; R<1> to R<4> respectively denote a substituent; m<1>, m<4> respectively denote an integer from 0 to 4; n<2>, m<3> respectively denote an integer from 0 to 2; (n) denotes an integer from 2 to 4. The sensitivity is enhanced in this way; the residual potential is lowered and the durability at the time of the repetitive use is 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 an Ab 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-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. Many studies have been conducted on this method because it is easy to create. Many compounds such as organic dyes and organic pigments have been proposed as carrier-generating substances having a carrier-generating function in such functionally separated photoreceptors.

For example, JP-A-54-22834, JP-A-55-73057
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 have discovered that a specific azo compound can act as an excellent active ingredient for electrophotographic photoreceptors. This completes the present invention. That is, the above object of the present invention is to form the following general formula "I", general formula [II], general formula [
(2) This is achieved by an electrophotographic photoreceptor characterized by having a photosensitive layer containing an Ab compound represented by the formula (2) or the general formula (2).

General formula [1] (In the formula, Cp each independently represents a coupler residue having a phenolic hydroxyl group, R1, R''R8 and R4 each represent a substituent, and ml and m4 each represent O-4
m2 and m8 each represent an integer of 0 to 2, and n represents an integer of 2 to 4. ) General formula [II (wherein Cp each independently represents a coupler residue having a phenolic hydroxyl group, RL, R2R3 and R4
each represents a substituent, ml and m4 each represent O
m2 and m3 each represent an integer of 0 to 2, and n represents an integer of 2 to 4. ) General formula [ml (in the formula, Cp each independently represents a coupler residue having a phenolic hydroxyl group, R', R2R3 and R4 each represent a substituent, mL and m4 each represent 0 to 4
m2 and m3 each represent an integer of 0 to 2, and n represents an integer of 2 to 4. ) General formula [ (In the formula, Cp each independently represents a coupler residue having a phenolic hydroxyl group, R1, R2R'' and R4 each represent a substituent, and mL and m4 each represent O-4
m2 and m3 each represent an integer of 0 to 2, and n represents an integer of 2 to 4. ) The present invention will be explained in more detail below.

In general formula [I] to general formula [IV], -N=
Two to four N-Cp are contained and can be bonded at any position where RL, R1R3 or R4 can be substituted. However, -N=N-ml depending on the number of Cp and the substitution position
, m'', m'', and m' are assumed to change as appropriate. Furthermore, in the present invention, when ml is 2 or more, m1 R1s may be the same or different (, m'', when m'' is 2, m2
R2 and m'' RB may be the same or different, and when m4 is 2 or more, m4 R4 may be the same or different.

General formula [I Col General formula [■ When the number of -N=N-Cp in C is 2 or more, n Cp 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 [V] to [XVT] can be mentioned.

General formula [V] (wherein, Yl 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 [■ (in the formula, 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) , represents an aryloxycarbonyl group or an acyl group, and Z is 2 for condensing with a benzene ring to form an aromatic hydrocarbon ring or a heterocycle.
Indicates a valence group. ) General formula [] (In the formula, R1 and Rv each represent a hydrogen atom, a lower alkyl group, an aryl group, or a heterocyclic group, and RL and R2
may be bonded to each other to form a ring. Z has the same meaning as in the general formula [VI] above. ) General formula [■] (wherein, Rt, R2 and Z each represent the above-mentioned general formula [■]
■] has the same meaning as in []. ) (wherein R3 and R4 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 R1 combine with each other to form a ring. (Z has the same meaning as in the general formula [VI] above.) General formula [X] (wherein, R1 and R, respectively, have the same meaning as in the general formula [■]
or has the same meaning as in general formula [IX]. ) General formula [X I ] (wherein, R1 and Z each represent the general formula [VI]
or has the same meaning as in [■]. ) general formula [Xn
] R1 (In the formula, R3 represents an alkyl group, an unsaturated alkyl group, or an aryl group.) General formula [X III] [In the formula, Rs, R, , R, and R8 are each a hydrogen atom, a halogen atom, It represents an alkyl group, a vinyl group, a substituted amino group or an aryl group, and R6 also represents -C-
R-engineer. (However, R1° represents an alkyl group, an aryl group, a heterocyclic group, a vinyl group, an amino group, or an alkoxy group.

) is shown. General formula [XrV] (In the formula, Q represents a divalent aromatic hydrocarbon group or a divalent heterocyclic group.) However, the polygroups in the above general formulas [V] to [XIV] have a substituent. may have.

In each of the general formulas [V] to [X m], examples of the 7 trogen atoms include fluorine atom, chlorine atom, bromine atom, iodine atom, etc., and examples of substituted or unsubstituted alkyl groups include methyl group, ethyl group, etc. , 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-naphthylmethyl group, allyl group, 2-hydroxyethyl group group, 2-methoxyethyl group, 3-morpholinopropyl group, 2-diethylaminoethyl group, 3-carbazolylmethyl group, and the like. The lower alkyl group represented by R 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. Examples of 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, acetoxy group, acyloxy group such as 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 combining R and R2 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 general formula [XIV] 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-phinidine group, an 0-naphthylene group, a 1,8-naphthylene group,
Examples include divalent condensed polycyclic aromatic hydrocarbon groups such as a 1,2-anthraquinonylene group and a 9,10-phenanthrylene group.

Further, as the divalent heterocyclic group, for example, 3゜4-pyrazolediyl group, 2,3-pyridinediyl group, 3,4-
pyridinediyl group, 4,5-pyrimidinediyl group, 6,
Examples include divalent heterocyclic groups such as 7-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; 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, niacetyl group,
Acyl groups such as benzoyl groups; aryloxy groups such as phenoxy groups; arylalkoxy groups such as benzyloxy groups;
Examples include carbonyl 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 [■],
Particularly preferred is a group selected from the groups represented by [IX] and [XrV].

The substituents represented by R1 to R4 in the general formulas [I] to [IV] 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 groups; Aryloxy groups such as phenoxy; Hydroxyl: nitro; cyano; amino; substituted amino groups such as dimethylamino, diethylamino and dibenzylamino; 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 and substituted aminocarbonyl groups such as phenylaminocarbonyl groups; arylalkoxy groups such as benzyloxy groups and phenethyloxy groups, aryl groups, heterocyclic groups, and heterocyclic groups.

Specific examples of coupler residues represented by Cp in general formulas [1] to [IV] are shown below, but the present invention is not limited thereto.

Specific examples of groups having an azo group bonding to the coupler residue Cp are shown below in the blank space in general formulas [1] to [rV], but the present invention is not limited by these. It's not a thing.

(t-1) N=N- N=N- -N=N (I-16) ○CH.

(I -19) -N=N N=N- Below margin (II-1) (n-2) (n-3) (U-6) N=N- -N=N -N=N (I[ -15) I (III-1) (III-2) (I[[-3) (I[l-4) N=N- N=N- He=N - (I[[-5) (I[ l-6) (III-7) (III-8) N=N- N=N- (II[-9) (I[[-10) N=N- -N=N (III-11) (I [[-12) (Iff-13) (III -14) (I[r-,15) N=N- N=N- N=N- Below - Margin - N=N N=N- (IV-4 ) (IV-6) N=N- (IV-10) N=N- -N=N to=to- The azo compounds represented by the general formulas [I] to [IV] of the present invention are: It can be synthesized by a known method.

Synthesis Example 1 Compound [i] 0.01 mol was added to 101 g of hydrochloric acid and 20 g of water.
1Q, and a solution of 002 mol of sodium nitrite dissolved in 5 nR of water was added dropwise while keeping the temperature below 5°C. 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 501 g of water was added to the filtrate. The precipitated tetrazonium salt was collected by filtration and treated with N,N-dimethylformamide (DMF) 100
Dissolved in mQ. While maintaining the temperature at 5°C, compound (n) 0.
02 mole to DMF 200. A solution dissolved in Q was added dropwise. 0.04 mol of triethanolamine was added to D M F 30. while keeping the temperature below 5°C. The solution dissolved in Q was added dropwise, and the mixture was stirred at 5° C. or lower for 1 hour and then at room temperature for 4 hours. After the reaction, the product was collected by filtration, washed with DMF, washed with water, and dried to obtain 0.0064 mol of the compound (m) according to the present invention. This compound (III) was confirmed to be a compound according to the present invention based on elemental analysis values.

Yield is 64%, The elemental analysis values are as follows. It was ri.

Calculated value (%) 71.31 Actual value (%) 71.29 Below margin Compound (1) Synthesis Example 2 0.02 mol of compound (1') and 0.05 mol of sodium hydroxide powder were added to 20% with dimethyl sulfoxide 22 While stirring at ℃, 0.01 mol of tetrazonium borohydrofluoride (■') was added to 3! of dimethyl sulfoxide. Add the solution dissolved in the solution dropwise and hold for 3 hours. 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 (■
') was confirmed to be a compound according to the present invention based on elemental analysis values. The yield was 68%, and the elemental analysis values were as follows.

HN Calculated value (%) 76.06 3.29 13.15 Actual value (%) 76.03 3.46 13.08 Compound (U') Mixed compound of stool number isomers (■゛) Synthesis example 3 Compound (1 ') 0.01 mol and 3001 mol of naphthol A are dissolved in 32 mol of dimethyl sulfoxide.

Compound (I) was added while keeping this solution at a temperature of 20-23°C.
I') After adding a solution of tetrazonium borohydrofluoride (■') obtained by diazotizing 0.01 mol in dimethyl sulfoxide 22, 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, and then dried 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 70%, and the elemental analysis values were as follows.

HN Calculated value (%) 76.72 3,74 8.44 Actual value (%) 76.67 3.89 8.35 Compound*(
1'') Compound (■'') Compound ([ff-) Compound (F'') Other compounds of the present invention can also be produced in the same manner as in the above synthesis examples.

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 in order to inject them into the carrier transport layer without causing damage.

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, Addition polymerization resins such as phenolic resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, etc.
Examples include 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 0.00 times the amount of the carrier generation store relative to the carrier generation material.
The number of moles is preferably in the range of 5 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.
01 to 100 parts by weight, preferably 1 to 100 parts 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, silver oxide,
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, 112-trichloroethane, chloroform; ketones such as acetone, methyl ethyl ketone, cyclohexanone; esters such as ethyl acetate, butyl acetate; methanol, ethanol, propatool, butanol, cyclohexanol, Alcohols and their derivatives such as heptatool, ethylene glycol, methyl cellosolve, ethyl cellosolve, and acetic acid cellosolve; ethers and acetals such as tetrahydrofuran, 1,4-dioxane, furan, and furfural; pyridine, butylamine, diethylamine, ethylenediamine, Amines such as isopropanolamine;
One or more of nitrogen compounds such as amides such as N,N-dimethylformamide, their oil fatty acids 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 O~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
~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, quinazoline 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 azo 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, Ar2 and Ar< 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 Represents an alkyl 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.

In the general formula, Rt represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic group, and R2 represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group; Japanese Patent Publication No. 58-13464
No. 2 and No. 58-166354.

General formula (C) In the formula, Rt 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 amine group, and R6 is a substituted or unsubstituted aryl group or a substituted Or it represents an unsubstituted heterocyclic group. Regarding the synthesis method of these compounds and their exemplified compounds, see Japanese Patent Publication No. 57-1487.
It is described in detail in the specification of Japanese Patent Application No. 50, 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 100:1 to 500:O to
500 is preferable, and the thickness of the photosensitive layer to be formed is 5 to 50.
It is preferably 5 to 30 μm, particularly preferably 5 to 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 preferable, more preferably 100:01-5
It is 0.

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 that has excellent durability, and has little variation 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 Tsukumi Kagaku Kogyo Co., Ltd.) 2
g was added to 110 g of tetrahydrofuran and dispersed in a ball mill for 12 hours. The film thickness when this dispersion is dried is 0.
It was coated to a thickness of 5 μm to form a carrier generation layer, and on top of that, as a carrier transport layer, 6 g of a carrier transport substance (K-1) having the following structural formula and a polycarbonate resin [
Kneepilon Z-200J (manufactured by Mitsubishi Gas Chemical Co., Ltd.) 10
A carrier transport layer was formed by applying a solution obtained by dissolving 1,2-dichloroethane 801112 in 1,2-dichloroethane 801112 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 photoconductor obtained in the above manner was
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.
The surface potential (Vo) and the exposure amount used to attenuate the surface potential by half (half-reduced exposure amount) El/2 were determined by irradiating with halogen lamp light at 5 lux·sec. The results are shown in Table 1.

Kuku Kuku Kuk Kukuni -1 to -2 to -3 to -4 to -5 to -8 to -9 to -10 Below margin Comparative Example 1 Except for using the following azo compound (G-1) as a carrier generating substance , comparative photoreceptor sample No. 1 was prepared in the same manner as in Example 1.
, 20 were created.

(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 compared to the comparative photoreceptor.

Example 2 A 0.0-thick film made of vinyl chloride-vinyl acetate-maleic anhydride copolymer "S-LEC MF-10J (manufactured by Sekisui Chemical 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 2 g of CGMA-1 and polyvinyl butyral resin [S-LEC BH-3J
(manufactured by Tanezu Chemical Industry Co., Ltd.) 2g and 10% of tetrahydrofuran
The dispersion was mixed with 0.0 μm and dispersed for 24 hours using a ball mill dispersion machine, and then applied to a film thickness of 0.6 μm after drying.
A carrier generation layer was formed.

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.

The photoreceptor sample 21 prepared in this manner was transferred to an electrophotographic copying machine rU-Bix 1550M RJ (Koni
When the image was copied using a modified machine manufactured by CA Corporation, a copy image with high contrast, faithful to the original image, and clear was obtained. In addition, when 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, we were able to obtain clear copied images with high contrast even after so many repetitions. It was done.

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 an azo compound represented by the following structural formula (G-2). When N022 was created and the copied image was evaluated in the same manner as in Example 2, the contrast decreased after around 30,000 repetitions in terms of durability under high temperature and high humidity.
Only images with a lot of fog were obtained.

Example 3 Vinyl chloride-vinyl acetate-
Maleic anhydride copolymer, “S-LEC MF-10J
(manufactured by Sekisui Chemical Co., Ltd.) with a thickness of 0.05 μm, and on top of that, a carrier transport substance with the following structural formula (
A carrier transport layer was formed by applying a solution obtained by dissolving 6 g of K-11) and 10 g of polycarbonate resin "Panlite L-1250J" in 801 g of 1,2-dichloroethane so that the film thickness after drying was 15 μm. .

(K-11) Furthermore, carrier generating substance A-5, A-8 or A-
102 g, 1.5 g of the above carrier transport material and 2 g of polycarbonate resin "Panlite L-1250J"
2-dichloroethane 3o1. In addition to photoreceptor sample No.
23 to 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.

Table 2 with blank spaces below Example 4 Photoreceptor samples No.
26-43 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 VH of the unexposed area and the potential VL of the exposed area 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. 044 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.

For the rest of the night, please see Table 3 *G-1 is for the compounds used in Comparative Example 1 -12 to -13 to -14 to -15 to -16 to -17 to -18 to -20 The above examples, As is clear from the results of the comparative examples, the photoreceptor samples of the present invention are significantly superior to the comparative photoreceptor samples in terms of stability, sensitivity, durability, and compatibility with a wide range of carrier transport substances. Understood.

Claims (1)

[Claims] The following general formula [I], general formula [II],
An electrophotographic photoreceptor characterized by having a photosensitive layer containing an azo compound represented by the general formula [III] or the general formula [IV]. 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 and m^4 each represent an integer of 0 to 4, m^2 and m^3 each represent an integer of 0 to 2, and n represents an integer of 2 to 4. ) 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, R^2, R^3, and R^4 each represents a substituent, m^1 and m^4 each represent an integer of 0 to 4, m^2 and m^3 each represent an integer of 0 to 2, and n represents an integer of 2 to 4. ) General formula [III] ▲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, R^2, R^3 and R^ 4 each represents a substituent, m^1 and m^4 each represent an integer of 0 to 4, m^2 and m^3 each represent an integer of 0 to 2, and n represents an integer of 2 to 4. ) General formula [IV] ▲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, R^2, R^3 and R ^4 each represents a substituent, m^1 and m^4 each represent an integer of 0 to 4, m^2 and m^3 each represent an integer of 0 to 2, and n is an integer of 2 to 4. )