JPH0420971A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide the electrophotographic sensitive body having a sufficient sensitivity and good durability by incorporating at least one azo compds. expressed by specific formula into the photosensitive layer on a conductive base. CONSTITUTION:The azo compds. expressed by the formula (where Ar1 denotes a substd. or unsubstd. arom. hydrocarbon ring or arom. heterocycle which may be bonded via a bond group; Ar2 denotes a substd. or unsubstd. arom. hydrocarbon ring or arom. heterocycle; R1 denotes an alkyl group or alkoxy group; (n) denotes 2 to 4 integer) is used as a charge generating material. The electrophotographic sensitive body having the excellent characteristics, such as high sensitivity and high durability, is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photoreceptor for electrophotography. More specifically, the present invention relates to an electrophotographic photoreceptor in which a photosensitive layer on a conductive support contains a specific azo compound as a charge generating substance.

[Conventional technology]

Conventionally, inorganic photosensitive materials such as selenium, cadmium sulfide, and zinc oxide have been widely used as photosensitive materials for electrophotographic photoreceptors. However, photoreceptors using these photosensitive materials do not fully satisfy the performance requirements for electrophotographic photoreceptors, such as sensitivity, photostability, moisture resistance, and durability. For example, a photoreceptor using a selenium-based material has excellent sensitivity, but the characteristics of the photoreceptor tend to deteriorate due to crystallization due to heat or adhesion of dirt. Furthermore, since it is manufactured by vacuum deposition, it is expensive, and it also has many drawbacks, such as being difficult to process into a belt shape because it is not flexible. Photoreceptors using cadmium sulfide-based materials have problems in moisture resistance and durability, and photoreceptors using zinc sulfide have problems in durability.

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

For example, as an organic photosensitive material that has been partially put into practical use,
．． 7-) A combination of Lietro 9-fluorenone and polyN-vinylcarbazole is known. However, the photoreceptor using this material had low sensitivity (and was not satisfactory in terms of durability either).

In recent years, among photoreceptors developed to improve the above-mentioned drawbacks, a functionally separated photoreceptor in which charge generation function and charge transport function are shared by separate substances has been attracting attention. In this functionally separated type photoreceptor, materials having respective functions can be selected from a wide range of materials and combined, so that it is possible to produce a photoreceptor with high sensitivity and high durability. Many materials have been proposed as charge generating materials for use in such functionally separated photoreceptors. Among these, photoreceptors using organic dyes or organic pigments as charge-generating substances have attracted particular attention in recent years.

For example, a photoreceptor using a disazo pigment having a styryl stilchen skeleton (Japanese Patent Application Laid-open No. 133445/1983),
A photoreceptor using a disazo pigment having a carbazole skeleton (JP-A-53-95033), a photoreceptor using a trisazo pigment having a triphenylamine skeleton (JP-A-53-132347), a distyrylcarbazole skeleton A photoreceptor using a disazo pigment having
14967) and a photoreceptor using a disazo pigment having a bisstilhene skeleton (Japanese Unexamined Patent Publication No. 17733/1983). However, these electrophotographic photoreceptors do not necessarily fully satisfy the required performance, and there has been a desire to develop an even better photoreceptor.

[Problem to be solved by the invention]

An object of the present invention is to provide an electrophotographic photoreceptor having sufficient sensitivity and good durability.

[Means to solve the problem]

The present inventors have made extensive studies to solve the above problems, and
As a result, - Funazura (+) (wherein, Ar represents a substituted or unsubstituted aromatic hydrocarbon ring or aromatic heterocycle which may be bonded via a bonding group, and Art is a substituted or unsubstituted represents an aromatic hydrocarbon ring or an aromatic heterocycle, R1 represents an alkyl group or an alkoxy group, and n represents an integer of 2 to 4. The inventors have discovered that it is possible to provide an electrophotographic photoreceptor having excellent characteristics, leading to the present invention.

In the general formula (I), Ar represents a substituted or unsubstituted aromatic hydrocarbon ring or aromatic heterocycle which may be bonded via a bonding group; examples of the aromatic hydrocarbon ring include benzene, naphthalene, etc. , anthracene, pyrene, phenanthrene, fluorene, anthraquinone, fluorenone,
Examples of aromatic heterocycles include thiophene, dihenzothiophene, pyridine, carbazole, hendioxazole, and hendithiazole. In addition, if a substituent exists, examples of the substituent include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, alkoxy groups such as methoxy group, aryl groups such as phenyl group and naphthyl group, diethylamino group, diphenyl group, etc. Substituted amino groups such as amino groups, halogen atoms such as fluorine atoms, chlorine atoms, bromine atoms, hydroxyl groups, nitro groups,
Examples include cyano group.

Further, the aromatic hydrocarbon ring and the aromatic heterocycle may be bonded via a bonding group, but the bonding group is -
o--s--co-1-C)l=CB-, and the like.

Can be preferably used in the present invention Ar below A specific example is given below.

When n=2, th (A-9) When n=3, When n=4, Ar, the aromatic hydrocarbon ring is benzene,
Examples include naphthalene, anthcene, anthraquinone, torene, phenanthrene, fluorene, and fluorenone. Examples of aromatic heterocycles include thiophene, furan, pyridine, carbazole, indole, hensifuran, and dihenzofuran. In addition, when it has a substituent,
Substituents include alkyl groups such as methyl, ethyl, propyl, and butyl groups, alkoxy groups such as metquine, ethquine, propoxy, and butoxy groups, halogen atoms such as chlorine, fluorine, and bromine atoms, and trifluoro Examples include halomethyl groups such as methyl groups, dialkylamino groups such as dimethylamino groups and diethylamino groups, nitro groups, cyano groups, carboxyl groups, and esters thereof.

Further, in R+, examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, etc., and examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, etc.

Specifically, the azo compounds that can be preferably used in the present invention are
Shown in the table. In addition, in the table, in Ar+, (A-1) ~
(A-13) represents the structural formula shown above.

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

- Diazotize the amine compound represented by (It)Arl +NHz), l(II) (where n is the same as in general formula (I)), and then use the diazotized compound as it is. Alternatively, after isolation as a borofluoride salt,
- Funagura (I [I) (in the formula, ^r2 and R1 are - Funagura (I
) is the same as ) It can be easily produced by coupling with a coupler compound represented by:

The electrophotographic photoreceptor of the present invention contains at least one azo compound represented by -Funzo (I) as a charge generating substance in a photosensitive layer on a conductive support. Typical configurations of such photoreceptors are shown in FIGS. 1 and 2. The photoreceptor shown in FIG. 1 is a photoreceptor in which a dispersion type photoreceptor N4 in which a charge generating substance 2 and a charge transporting substance 3 are dispersed in a binder is provided on a conductive support l. A photosensitive layer 4' is provided on a conductive support 1, and includes a charge generation layer 6 in which a charge generation substance is dispersed in a binder, and a charge transport N5 in which a charge transport substance is dispersed in a binder. It is the body.

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

In the photoreceptor shown in FIG. 2, imagewise exposed light passes through the charge transport layer, and a charge generation substance generates charges in the charge generation layer. The generated charges are injected into the charge transport layer, and the charge transport material performs the transport.

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

That is, the conductive support used in the photoreceptor of the present invention includes a metal plate such as aluminum, copper, or zinc, a plastic sheet such as polyester, or a plastic film on which a conductive material such as aluminum or SnO□ is adhered. Alternatively, conductive treated paper, resin, etc. are used.

As binders, vinyl polymers such as polystyrene, polyacrylamide, and poly-N-vinylcarbazole, and condensation resins such as polyamide resins, polyester resins, epoxy resins, phenoxy resins, and polycarbonate resins are used. Any resin that is adhesive to the body can be used.

Charge transport materials are generally classified into two types: hole transport materials and electron transport materials, and both can be used in the photoreceptor of the present invention. In addition to electron-accepting substances that easily transport electrons such as trinitrofluorenone or tetranitrofluorenone, examples of hole-transporting substances include polymers containing heterocyclic compounds such as poly-N-vinylcarbazole, and triazoles. derivatives, oxadiazole derivatives, imidazole derivatives, birapurine derivatives, polyarylalkane derivatives, phenylenediamine i1,
Examples include electron-donating substances that easily transport holes, such as hydrazone derivatives, amine-substituted chalcone derivatives, triarylamine derivatives, carbazole derivatives, and stilchene derivatives.

For example, 9-ethylcarbazole-3-aldehyde-
1-Methyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde-1-benzyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde-11-diphenylhydrazone, 4-diethylaminostyrene-β aldehyde-1 -Methyl-1-phenylhydrazone, 4-methoxynaphthalene-1-aldehyde 1
-hensyl-1-phenylhydrazone, 4methoxybenzaldehyde-1-methyl-1-phenylhydrazone,
2,4-dimethoxybenzaldehyde-1-benzyl-
1-phenylhydrazone, 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, 4-methoxybenzaldehyde-1-hensyl-1-(4-methoxy)phenylhydrazone, 4-diphenylaminobenzaldehyde-1-benzyl-1-phenyl hydrazone,
4-dibenzylaminobenzaldehyde-1,1-diphenylhydrazone, LL-bis(4-dibenzylaminophenyl)propane, tris(4-diethylaminophenyl)methane, 1,1-bis(4-dibenzylaminophenyl)propane , 2.2'-dimethyl-4,4'-bis(diethylamino)triphenylmethane, 9-(4-
diethylaminostyryl)anthracene, 9-bromo-
1O-(4-diethylaminostyryl)anthracene,
9-(4-dimethylaminobenzylidene)fluorene,
3-(9-fluorenylidene)-9-ethylcarbazole, 1,2-bis(4-diethylaminostyryl)benzene, 1,2-bis(2,4-dimethoxystyryl)benzene, 3-styryl-9-ethylcarbazole, 3-
(4-methoxystyryl)-9-ethylcarbazole,
4-diphenylaminostyrylbene, 4-dibenzylaminostyrylbene, 4-ditolylaminostyrylbene,
1-(4-diphenylaminostyryl)naphthalene, 1
-(4-diethylaminostyryl)naphthalene, 4°-
Diphenylamino-α-phenylstilbene, 4'-methylphenylamino-α-phenylstilbene, 1-phenyl-3-(4-diethylaminostyryl)-5-(
4-diethylaminophenyl)pyrazoline, 1-phenyl-5-(4-dimethylaminostyryl)-5-(4-
dimethylaminophenyl) pyrazoline, etc.

Other hole transport substances include, for example, 2.5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole, 2.5-bis[4-(4-diethylaminostyryl)phenyl] -1,3,4-oxadiazole, 2-(9-ethylcarbazol-3-yl)-5-
(4-diethylaminophenyl)-1,3,4-oxadiazole, 2-vinyl-4-(2-fumarphenyl)-5-(4-diethylaminophenyl)oxazole, 2-(4-diethylaminophenyl)-4 -Phenyloxazole, 9-C3-(4-diethylaminophenyl)-2-propenylidene)-9H xanthine, poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, pyrene formaldehyde resin, ethyl Examples include carbazole formaldehyde resin.

Examples of the electron transport substance include chloranil, propentaanyl, tetracyanoethylene, tetracyanoquinodimethane, 2.4.7-) dinitro-9 fluorenone,
2,4.5.7-tetranitro-9-fluorene, 2,
4.5.7-Titranitroxanthone, 2.4.8-
) linitrothioxanthone, 2,6.8-) dinitro-4H-indeno(I,2-b)thiophen-4-one, 1,3.7-dolinitrodibenzothiophene-5,5
- Dioxide, etc.

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

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

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

In addition, in the photoreceptor shown in FIG. 2, the charge generation layer 6
The thickness is preferably 0.01 to 5 μm, more preferably 0.05 to 2 μm. This thickness is 0.01 μm
If it is less than 5 μm, the generation of charge will not be sufficient, and if it exceeds 5 μm, the residual potential will be high, which is not practical, and
The thickness of the charge transport layer 5 is preferably 3 to 50 μm, and more preferably 5 to 30 μm. If the thickness is less than 3 μm, the amount of charge will be insufficient, and if it exceeds 50 μm, the residual potential will be high, which is not practical. .

The content of the azo compound represented by general formula (I) in the photosensitive layer varies depending on the type of photoreceptor, but in the photoreceptor shown in FIG. 1, the content of the azo compound in the photosensitive layer 4 is preferably 50% by weight or less. ,
More preferably, it is 20% or less. Further, this layer preferably contains a charge transport material in a proportion of 10 to 95% by weight, more preferably 30 to 90% by weight. Also,
In the photoreceptor shown in FIG. 2, the proportion of the Ab compound in the charge generation layer 6 is preferably 30% by weight or more, more preferably 50% by weight or more. In addition, the charge transport layer 5 contains a charge transport substance in an amount of 10 to 95% by weight, preferably 30 to 95% by weight.
The content is 90% by weight. It should be noted that if the amount of the charge transport material in this layer is less than 10% by weight, hardly any charge will be transported, and if it exceeds 95% by weight, the mechanical strength of the photoreceptor will be poor, which is not practical.

[Functions and Effects] The electrophotographic photoreceptor of the present invention is easy to manufacture, has high sensitivity, and has good performance for repeated use by using the azo compound represented by (I) as a charge generating substance. It has excellent performance that does not deteriorate.

〔Example〕

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the embodiments of the present invention are not limited thereby.

Production example Synthesis of exemplified compound number 4 5-methoxysalicylic acid 50g10 in 300ml toluene
- Add 76 g of chloraniline, 0.1 d of N,N-dimethylformamide and 16.4 g of phosphorus trichloride,
The temperature was raised to ~110''C over 2 hours, and kept at the same temperature for 3 hours. After cooling, it was filtered and recrystallized from methanol to obtain 64 g of a coupler compound represented by the following structural formula.

4.1 g of this coupler compound was dissolved in 100 d of N,N-dimethylformamide, and 1.2 g of sodium hydroxide was dissolved in 100 d of N,N-dimethylformamide.
A solution of 30H1 of water was added to prepare a puller solution.

2.7-Diamitsufluorenone 1.4g 35% hydrochloric acid 3
．． After suspending the suspension in 5 m and 45 d of water and incubating at 60'C for 30 minutes, a solution of 1.4 g of sodium nitrite dissolved in 6Ii of water was added dropwise at 0°C. After stirring at 0°C for 1 hour, insoluble materials were removed and 15m of 42% borohydrogen fluoride was added. The precipitated crystals were filtered and dried to obtain 2.4 g of diazonium borofluoride.

2.4 g of the obtained diazonium borofluoride salt was mixed with N,N-
A solution dissolved in 20-dimethylformamide was heated to 10'C.
The mixture was added dropwise to the coupler liquid over a period of 30 minutes. The mixture was gradually warmed to room temperature and stirred for 3 hours, and 11 ml of acetic acid and 50 ml of water were added, and the precipitate precipitated was collected by filtration and dried.

Powder that is recrystallized from N,N-dimethylformamide/methanol and exhibits a black color 2. Obtained Og (melting point 270°C
that's all).

This product was confirmed to be Exemplified Compound Kan 4 based on elemental analysis values and infrared absorption spectrum.

Elemental analysis value CHN C1 calculation (i (%) 62.52 3.56 10.6
7 9.02 Actual value (%) 63.00 3.42
10.34 8.73 The infrared absorption spectrum (KBr method) is shown in FIG.

Example 1 0.5 parts of polyester resin (trade name "Vylon 200" manufactured by Toyobo), 0.5 parts of Exemplary Compound 57!IJNn4 and 50 parts of ethyl cellosolve were ground and mixed in a ball mill,
The resulting dispersion was applied to an aluminum plate using a wire bar and dried at 80°C for 20 minutes to form a charge generation layer of about 1 μm. On this charge generation layer, 1 part of a hydrazone compound represented by the following structural formula, a polycarbonate resin (trade name [Panrai] K-1300J manufactured by Teijin Kasei)
A solution prepared by dissolving 1 part of chloroform in 10 parts of chloroform was applied using a wire bar, dried at 80°C for 30 minutes, and the thickness was approximately 18 cm.
A charge transport layer having a thickness of .mu.m was formed to produce a laminated photoreceptor shown in FIG.

Electrostatic copying paper testing device (model E P made by Ro Denki Seisakusho for
A-8100) was used to charge the photoreceptor by corona discharge with an applied voltage of -6 KV, the surface potential v0 at that time was measured, and then it was left in a dark place for 2 seconds to measure the surface potential v2 at that time. With the surface illuminance of the photoconductor at 51 ux, irradiate it with light from a halogen lamp (color temperature 2856'K), measure the time for the surface potential to reach 1/2 of the surface potential value E1, and calculate the half-reduced exposure amount E1. /2 (lux-sec) was calculated. Furthermore, the surface potential ν,2, that is, the residual potential, was measured after 10 seconds of light irradiation.

Examples 2 to 20 Photoreceptors were prepared in the same manner as in Example 1, using the compound of the present invention as a charge-generating substance, and (CT-1) and a compound represented by the following structural formula as a charge-transporting substance, respectively.
E 1/2 was calculated. The charge generating substance, charge transporting substance and E1/2 used are shown in Table 2 together with Example 1.

t Is Comparative Example 1 Same as Example 1 except that the disazo compound represented by the following structural formula described in Japanese Patent Publication No. 55-42380 was used as the charge generating substance and the above (CT-4) was used as the charge transporting substance. A photoreceptor was produced in the same manner.

E1/2 was 12.0 (lux・5ec).

Example 21 The photoreceptor produced in Example 1 was attached to a commercially available electrophotographic copying machine to make copies, and even on the 10,000th copy, a clear image without any shadows that was faithful to the original was obtained.

As described above, it can be said that the electrophotographic copying machine using the Ab compound of the present invention has high sensitivity and stable performance with repeated use, and is also excellent in durability.

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

[Brief explanation of drawings]

FIGS. 1 and 2 are cross-sectional views showing an example of the structure of the principle of electrophotographic copying. In addition, in FIG. 1 and FIG. 2, each reference numeral is as follows. 1- Conductive support 4.4゛ Photosensitive layer 2---
Charge generating substance 5 Charge transporting layer 3---Charge transporting substance 6---Charge generating layer FIG. 3 shows exemplary compound NO.
The infrared absorption spectrum (KBr method) of No. 34 is shown. Patent applicant: Mitsui Toatsu Chemical Co., Ltd. Wavenumber (cm-')

Claims (1)

[Claims] 1) The photosensitive layer on the conductive support has the general formula (I)▲mathematical formula,
There are chemical formulas, tables, etc. ▼ (I) (In the formula, Ar_1 represents a substituted or unsubstituted aromatic hydrocarbon ring or aromatic heterocycle that may be bonded via a bonding group, and Ar_2 is a substituted or unsubstituted represents an aromatic hydrocarbon ring or an aromatic heterocycle, R_1 represents an alkyl group or an alkoxy group, and n represents an integer of 2 to 4.) Characterized by containing at least one azo compound represented by A photoreceptor for electrophotography.