JPH04186363A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide an electrophotographic sensitive body with high sensitivity and small residual potential and enable stable potential characteristic of the sensitive body to be obtained even when the sensitive body is used repeatedly by combining a specific carrier generating material and a specific carrier transport material. CONSTITUTION:A perylene compound indicated by the formula I or II or a perylene compound indicated by mixing of the formulae I and II is used as a carrier generating material and a styryl compound indicated by the expression III is used as a carrier transport material. In the expressions I, II, Z indicates an atom group needed for forming substituted and non-substituted aromatic cycles. In the formula III, Ar1 to Ar4 indicate substituted and non-substituted aromatic groups. Benzene, naphthalene, anthracene, thiophene, pyridine and carbazole are preferable as the aromatic groups and benzene and naphtalene are most preferable. An electrophotographic sensitive body is therefore high in sensitizity and its potential stability can be obtained when it is used repeatedly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and particularly to a highly sensitive photoreceptor useful for printers, copying machines, and the like.

[Prior art]

Conventionally, inorganic photoreceptors provided with a photosensitive layer mainly composed of inorganic photoconductive substances such as selenium, zinc oxide, and cadmium sulfide have been widely used as electrophotographic photoreceptors. However, these materials have not always been satisfactory in terms of characteristics such as photosensitivity, thermal stability, moisture resistance, and durability, which are required as electrophotographic photoreceptors for copying machines and the like.

For example, selenium crystallizes due to heat, fingerprint stains, etc., so its properties as an electrophotographic photoreceptor tend to deteriorate.

Further, electrophotographic photoreceptors using cadmium sulfide have poor moisture resistance and durability, and electrophotographic photoreceptors using zinc oxide also have problems in durability. Electrophotographic photoreceptors made of selenium or cadmium sulfide also have the drawback of severe restrictions in manufacturing and handling due to toxicity.

In order to improve the drawbacks of such inorganic photoconductive materials, attempts have been made to use various organic photoconductive materials in the photosensitive layer of electrophotographic photoreceptors, and active research has been conducted in recent years. . For example, Japanese Patent Publication No. 50/10496 describes an organic photoreceptor having a photosensitive layer containing polyvinylcarbazole and trinitrofluorenone. but,
This photoreceptor does not have sufficient sensitivity and durability. Therefore, a functionally separated electrophotographic photoreceptor has been developed in which the carrier generation function and the carrier transport function are assigned to different substances.

In such electrophotographic photoreceptors, materials can be selected from a wide range of materials, so it is easy to obtain desired characteristics, and it is therefore expected that organic photoreceptors with high sensitivity and excellent durability can be obtained. ing.

Various nurturing compounds have been proposed as carrier-generating substances and carrier-transporting substances for such functionally separated electrophotographic photoreceptors, and examples of carrier-generating substances include polycyclic quinone compounds represented by dibromoanthroni. ,
Bylylium compounds, eutectic complexes of biryllium compounds and polycarbonates, squareium compounds, phthalonanine compounds, azo compounds, and the like have been put into practical use. Further, as carrier transport substances, for example, pyrazoline compounds, polyarylalkane compounds, triphenylamine compounds, hydrazone compounds, diaminobiphenyl compounds, styrylbenzene compounds, etc. have been put into practical use.

[Problem that the invention seeks to solve]

The above-mentioned carrier-generating substances and carrier-transporting substances have made it possible to dramatically improve the performance of organic photoreceptors compared to conventional materials. However, at present, faster response is required, and new technological Results are required. In developing an excellent photoreceptor, the selection of carrier-generating substances and carrier-transporting substances is important, but a carrier-transporting substance that is effective for a particular carrier-generating substance may not necessarily be effective for other carrier-generating substances. It does not work effectively, and a carrier generating substance that is effective against a specific carrier transporting substance is not necessarily effective against other carrier transporting substances. Therefore, in order to fully express the functions of both substances, it is important to select a mutually suitable combination. If this combination is not appropriate, not only the sensitivity as an electrophotographic photoreceptor will deteriorate, but also the residual potential will increase because the discharge efficiency, especially at low electric fields, will decrease. In such a case, for example, in a copying machine, charge accumulates due to repeated use, and as a result, toner adheres to non-image areas, causing background smudges and making it impossible to obtain clear images. Alternatively, in an inappropriate combination, a significant decrease in charging ability occurs, resulting in a decrease in image quality in a copying machine.

[Purpose of the invention]

The purpose of the present invention is to solve the above problems by combining a conventional carrier-generating substance and a specific carrier-transporting substance, and to achieve high sensitivity, low residual potential, and stable potential characteristics even after repeated use. The purpose of the present invention is to provide an electrophotographic photoreceptor with such advantages.

C Structure and Effects of the Invention] The object of the present invention is to generate a perylene compound represented by the following general formula [I] or [+1], or a perylene compound obtained by mixing [I] and [I[] as a carrier. This can be achieved by using a styryl compound represented by the following general formula [I[11] as a carrier transporting substance.

General Formula [I] General Formula [I11 In the formula, Z represents an atomic group necessary to form a substituted or unsubstituted aromatic ring.

2 is preferably a benzene ring, a naphthalene ring,
Examples include anthracene ring, 7-enanthrene ring, pyridine ring, pyrimidine ring, pyrazole ring, and anthraquinone ring, and particularly preferred are benzene ring and naphthalene ring.

Examples of the substituent for Z include alkyl, alkoxy, aryl, aryloxy, acyl, acyloxy, amino, carbamoyl, halogen, nitro, cyano, and the like.

General Formula [1[II] In the formula, Art Ar, Ar, Ar represent a substituted or unsubstituted aromatic group. Preferred aromatic groups are benzene, naphthalene, anthracene, thiophene, pyridine, and carbazole, and particularly preferred are benzene,
It is naphthalene. Substituents for aromatic groups include alkyl, aryl, alkoxy, aryloxy, acyl,
Examples include acyloxy, norogen, amino, and cyano, but particularly preferred are carbon [alkyl having 1 to 6 carbon atoms, alkoxy having 1 to 6 carbon atoms, acyl having 1 to 6 carbon atoms, norogen, and amino] .

The compound represented by general formula (I) or CI) can be easily synthesized according to reaction formula (1).

Reaction formula (1) □ Furthermore, the compound represented by general formula [III] can be easily synthesized according to reaction formula (2).

Reaction formula (2) Specific examples of compounds represented by general formulas [11 and [I] are shown below.

Z represents Z in the general formula.

Next, a carrier transport substance represented by the general formula [II[] In the present invention, other carrier transport substances may be used in combination with the above-mentioned compounds. Examples of such carrier transport substances include compounds having a nitrogen-containing heterocyclic nucleus and its condensed ring nucleus represented by oxazole, oxadiazole, thiazole, thiadiazole, imidazole, etc., polyarylalkane-based compounds, and pyrazoline-based compounds. compounds, hydrazone compounds, triarylamine compounds, styryl compounds, styryltriphenylamine compounds, β
-Phenylstyryltriphenylamine compounds, butadiene compounds, hexatriene compounds, carbazole compounds, condensed polycyclic unformed metal compounds, and the like.

Various configurations of photoreceptors are known.

Although the photoreceptor of the present invention can take any of these forms, it is preferably a layered or dispersed functionally separated photoreceptor. In this case, the configuration is usually as shown in FIGS. 1 to 6. In the layer structure shown in FIG. 1, a carrier generation layer 2 is formed on a conductive support l, and a carrier transport layer 3
A photosensitive layer 4 is formed by laminating these layers, and FIG. 2 shows a photosensitive layer 4' in which the carrier generation layer 2 and carrier transport layer 3 are reversed. 3, an intermediate layer 5 is provided between the photosensitive layer 4 and the conductive support l having the layer structure shown in FIG. 1, and FIG. 4 shows the photosensitive layer 4' and the conductive support l having the layer structure shown in FIG. An intermediate layer 5 is provided between the two. The layer structure shown in Figure 5 is one in which a photosensitive layer 4'' containing a carrier generating substance 6 and a carrier transporting substance 7 is formed, and Figure 6 shows the layer structure between such a photosensitive layer 4'' and a conductive support l. An intermediate layer 5 is provided therein. In the configurations shown in FIGS. 1 to 6, a protective layer can be further provided on the outermost layer.

In forming the photosensitive layer, it is effective to apply a solution in which a carrier-generating substance or a carrier-transporting substance is dissolved alone or together with a binder or an additive.

However, since the solubility of carrier-generating substances is generally low, in such cases, the carrier-generating substances are dispersed into fine particles in an appropriate dispersion medium using a dispersion device such as an ultrasonic dispersion machine, a ball mill, a sand mill, or a homomixer. An effective method is to apply the liquid.

A wide variety of solvents or dispersion media can be used to form the photosensitive layer.

For example, butylamine, ethylenediamine 7,N.

N-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, ethylene glycol dimethyl ether, toluene, xylene, acetophenone, chloroform, dichloromethane, dichloroethane, trichloroethane, methanol, Examples include ethanol, chlornol, butanol, and the like.

When a binder is used to form the carrier transport layer, any binder can be selected, but a hydrophobic polymer having film-forming ability is particularly desirable. Examples of such polymers include, but are not limited to, the following:

Polycarbonate Polycarbonate Z Resin Acrylic Resin Methacrylic Resin Polyvinyl Chloride Polyvinylidene Polystyrene Styrene-Butadiene Copolymer Polyvinyl Acetate Polyvinyl Formal Polyvinyl Butyral Polyvinyl Acetal Polyvinyl Carbazole Styrene-Alkyd Resin Silicone Resin Silicone-Alkyd Resin Silicone-Butyral Resin Polyester Phenolic resin Polyurethane Epoxy resin Vinylidene chloride-acrylonitrile copolymer Vinyl chloride-vinyl acetate copolymer Vinyl chloride-vinyl acetate-maleic anhydride copolymer The ratio of the carrier transport substance to the binder is 10 to 50.
It is desirable to set it to 0 wt%. The thickness of the carrier generation layer is 0.001 to 20 μm, and more preferably 0.05 to 5 μm.
m is preferred. The thickness of the carrier transport layer is l-100 μm.
However, 5 to 30 μm is more preferable.

The photosensitive layer may contain an electron-accepting substance for the purpose of improving sensitivity, reducing residual potential, or reducing fatigue during repeated use. Examples of such electron-accepting substances include succinic anhydride, maleic anhydride, dibromo succinic anhydride, heptatalic anhydride, tetrachlorophthalic anhydride,
Tetrabromo phthalic anhydride, 3-nitro phthalic anhydride,
4-nitrophthalic anhydride, pyromellitic anhydride, mellitic anhydride, tetracyanoethylene, tetracyanoquinodimethane, 0-dinitrobenzene, ■-dinitrobenzene, 1,3.5-trinitrobenzene, p-nitrobenzonitrile , picryl chloride, quinone chlorimide,
Chloranil, chloranil, dichlordicyano-p-benzoquinone, anthraquinone, dinitroanthraquinone,
9-fluorenylidenemalonodinitrile, polynitro-
9-fluorenylidenemalonodinitrile, picric acid,
0-nitrobenzoic acid, p-nitrobenzoic acid, 3.5-dinitrobenzoic acid, pentafluorobenzoic acid, 5-nitrosalicylic acid, 3.5-dinitrosalicylic acid, 7-talic acid,
Examples include mellitic acid and other compounds with high electron affinity. The addition ratio of the electron-accepting substance is preferably 0.01 to 200, more preferably 0.1 to 100, per 100 of the weight of the carrier generating substance.

Further, the photosensitive layer may contain deterioration inhibitors such as antioxidants and light stabilizers for the purpose of improving storage stability, durability, and environmental dependence resistance. Compounds used for such purposes include, for example, chromanol derivatives such as tocopherol and their etherified or esterified compounds, polyarylalkane compounds, hydroquinone derivatives and their mono- and dietherized compounds, benzophenone derivatives, benzotriazole derivatives, and thioethers. compounds, phosphonic acid esters, phosphorous esters,
Effective examples include phenylenediamine derivatives, phenol compounds, hindered phenol compounds, linear amine compounds, cyclic amine compounds, and hindered amine compounds.

Specific examples of particularly effective compounds
Hindered phenol compounds such as Examples include hindered amine compounds.

Metal plates and metal drums are used as conductive supports, and paper is also coated with a thin layer of conductive polymers, conductive metals such as indium oxide, or metals such as aluminum and palladium by coating, vapor deposition, lamination, etc. It is possible to use a substrate provided on a substrate such as a plastic film or a plastic film.

The photoreceptor of the present invention has the above-described structure, and as is clear from the following examples, it has excellent charging characteristics, sensitivity characteristics, and repeatability characteristics.

〔Example〕

(Synthesis example) 39.2 g of perylene-3,4,9,10-tetracarboxylic dianhydride, 32.4 g of o-7 22-diamine,
Mix 800mt of a-chlornaphthalene, 260mt
The reaction was carried out at ℃ for 6 hours. After cooling, the precipitated crystals were collected by filtration and washed repeatedly with methanol. By heating and drying, 51.1 g of dark green crystals (grain yield 95.3%) were obtained.

This was further purified by sublimation to obtain a mixture of compounds represented by the following two formulas.

Example 1 1 part of the carrier-generating substance obtained in the synthesis example and 50 parts of 1,2-dichloroethane as a dispersion medium were dispersed using a sand mill, and this was applied onto a polyester base coated with aluminum using a wire bar. , a carrier generation layer having a thickness of 0.3 μm was formed. Next, 1 part of carrier transport substance B-61; 1 part of polycarbonate resin "Nipiron Z200J (manufactured by Mitsubishi Gas Chemical Co., Ltd.) 1.31s, and a trace amount of silicone oil r KF-54" (manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed with 1.2-dichloroethane. 10 parts of the solution was applied using a blade coater, and after drying, a film thickness of 20μ■ was obtained.
A carrier transport layer was formed.

The photoreceptor thus obtained is referred to as sample 1. Examples 2 to 4 The carrier transport substance B-61 in Example 1 was replaced with B-22.
A photoreceptor of the present invention was prepared in the same manner as in Example 1, except that , B-42, and B-71 were replaced. These will be referred to as sample 2, sample 3, and sample 4, respectively.

Comparative Examples (1) to (2) Comparative photoreceptors were prepared in the same manner as in Example 1, except that the carrier transport substance B-61 in Example 1 was replaced with the following compounds Z-1 and Z-2. did. These will be referred to as comparative sample (1) and comparative sample (2), respectively.

Comparative Example (3) In Example 1, the carrier generating substance was the following compound Z-
A comparative photoreceptor was produced in the same manner as in Example 1, except that Example 3 was replaced with Example 1. This will be referred to as comparative sample (3).

(Z-3) (Evaluation 1) The sample obtained as described above was evaluated as follows using a paper analyzer EPA-8100 (manufactured by Kawaguchi Electric Co., Ltd.). First, corona charging was performed for 5 seconds under the condition of -6KV, and the surface potential Va immediately after charging and the surface potential Vi after being left for 5 seconds were determined.
lux), and the surface potential was set to 1/2V.
The exposure amount required to make i is E, 72, and the surface potential is -60
Exposure amount E required to lower the voltage from 0V to -100V
1°. /, 66 was found. Also, D = 100('Va
The dark decay rate was calculated from the formula -Vi)/Va (%). The results are shown in Table 1.

(Evaluation 2) The obtained sample also used a copying machine U-bix 1600
Attached to a modified machine (manufactured by Konica), unexposed area potential VI4%
The exposed part potential VL was determined, and after 10,000 repetitions, v, I, and V were determined. The results are shown in Table 2.

Table 1 Table 2 j! Example 5 Carrier transport material B-77; 1 part and 1.5 parts of polyester resin "Vylon 20U (manufactured by Toyobo Co., Ltd.)"
- A solution dissolved in 10 parts of dichloroethane was applied onto an aluminum drum by dip coating, and after drying, a carrier transport layer with a thickness of 15 μm was formed.

On the other hand, carrier generating substance A-3: 1 part, 3 parts of polyester "Pylon 200J (manufactured by Toyoori Co., Ltd.) as a binder resin, 15 parts of monochlorobenzene as a dispersion medium,
After dispersing 35 parts of 1,2-dichloroethane using a ball mill, carrier transport substance B-77 was further added at a ratio of 75 t% to the binder resin. The dispersion thus obtained was first applied onto the carrier transport layer by a spray coating method to form a carrier generation layer with a thickness of 4 μm.

The photoreceptor thus obtained was evaluated in the same manner as in Evaluation 1, except that the charging polarity was changed to positive polarity.

Va = 1330 (V) Vi = l150 (V) D -13.5 (%) E l/2 - 2.2 (1ux-sec) E
False oo/+++o-4,1 (1 ux 11 sec) As is clear from the above example, the electrophotographic photoreceptor of the present invention has high sensitivity and excellent potential stability during repeated use.

[Brief explanation of the drawing]

1 to 6 are cross-sectional views showing specific examples of the layer structure of the photoreceptor of the present invention. l... Conductive support 2... Carrier generation layer 3... Carrier transport layer 4.4', 4''... Photosensitive layer 5... Intermediate layer

Claims (1)

[Scope of Claims] A perylene compound represented by the following general formula [I] or [II] or a perylene compound obtained by mixing [I] and [II] is used as a carrier generating substance, and a perylene compound represented by the following general formula [III] An electrophotographic photoreceptor containing a styryl compound represented by the following as a carrier transporting substance. General formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ General formula [II] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [However, in the formula, Z forms a substituted or unsubstituted aromatic ring. Represents the required atomic group. ] General formula [III] ▲ Numerical formulas, chemical formulas, tables, etc. are available▼ [In the formula, Ar_1Ar_2Ar_3Ar_4 represents a substituted or unsubstituted aromatic group. ]