JP3158475B2 - Photoreceptor - Google Patents

Description

[Detailed description of the invention]

[0001]

FIELD OF THE INVENTION This invention relates to a photoreceptor having a photosensitive layer containing a novel distyryl compound.

[0002]

2. Description of the Related Art Conventionally, there are known photoreceptors having a photosensitive layer mainly composed of an inorganic photoconductive substance and those having a photosensitive layer mainly composed of an organic photoconductive substance. Inorganic materials have drawbacks such as high toxicity, poor film-forming properties, lack of flexibility, and high manufacturing costs.

[0003] On the other hand, researches on the use of organic photoconductive substances represented by polyvinylcarbazole compounds in the photosensitive layer of photoreceptors have progressed and have already been put to practical use. In general, organic photoconductive substances have better transparency, lighter weight, and superior film-forming properties than inorganic photoconductive substances, but they are inferior in terms of sensitivity, durability, and stability against environmental changes. Therefore, the charge generation function and the charge transport function in the photoconductive function are separately shared by different substances to achieve high sensitivity and repeated stability.
A function-separated photoreceptor having excellent durability has been developed.

The function-separated photoreceptor has a photosensitive layer in which a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material are laminated, or a charge generation material and a charge transport layer are laminated. material in a binder resin. In recent years, for example, JP-A-60-175052 and JP-A-62-1
Japanese Laid-Open Patent Publication No. 20346 discloses a photoreceptor containing a styryl compound having a symmetrical structure about a nitrogen atom as represented by the following general formula.

[0005]

[Chemical 2]

[0006]

Problems to be Solved by the Invention However, in the photoreceptor described above, repeated image forming processes such as charging, exposure, and neutralization cause ozone generated during charging and laser irradiation with high brightness. As a result, the charge-transporting substance deteriorates, and there are problems such as image blurring due to a decrease in charging potential or an increase in residual potential. Further, the distyryl compound having a symmetrical structure as described in the above publication has a large molecular size, and has the drawback of being less compatible with a binder due to steric hindrance and likely to precipitate crystals.

[0007] Accordingly, an object of the present invention is to solve the above-mentioned problems, and to provide a distyryl compound containing a distyryl compound excellent in compatibility with a binder and charge-transporting ability, having high sensitivity, excellent electrification ability and ozone resistance, and repeated use. Fatigue deterioration against
An object of the present invention is to provide a photoreceptor with stable electrophotographic properties.

[0008]

Means for Solving the Problems The present invention provides a photoreceptor having a photosensitive layer on a conductive support, wherein the photosensitive layer contains a distyryl compound represented by the following general formula (Ia) or (Ib) : It is characterized by

[0009]

[Chemical 3a]

(wherein R _{1 and} R ₂ are each independently a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom; R ₃ is each an optionally substituted alkyl group, aralkyl group, aryl group; Indicates a condensed polycyclic group or composite ring group.
_{Ar1 and} Ar2 independently represent a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, or a condensed polycyclic group, _each of which may have a substituent. Z ₁ is a benzene ring, carbon and acid
Heterocyclic ring or benzene ring formed by condensing with element, carbon
and a heterocyclic ring formed by condensation with sulfur may have a substituent. )

[Chemical 3b] (wherein R _{1 ,} R ₂ , R ₃ , Ar ₁ and Ar ₂ are (Ia) and
Same. Z2 is formed by condensation with a benzene ring and _carbon
The condensed ring may have a substituent. provided that R ₃ is a substituent
when Ar ₁ and Ar ₂ are phenyl groups optionally having
A phenyl group, each of which may independently have a substituent,
When taking either a phthyl group or a heterocyclic group at the same time
except for. ) general formulas ( Ia) and (Ib) used in the present invention
The method for producing the distyryl compound of is described below.

The distyryl compound of the present invention can be, for example, an aldehyde compound represented by the following general formula (II)

[0012]

[Chemical 4]

(In the formula, R ₁ , R ₂ , R ₃ , Ar ₁ and Ar ₂ have the same meanings as ( Ia) and (Ib) .) An aldehyde compound represented by the following general formula (III) is condensed. can be synthesized by

[0014]

[Chemical 5]

(In the formula, Z is Z ₁ of (Ia), Z ₂ of (Ib)
synonymous with X is

[0016]

[Number 1]

or a dialkyl group or diarylphosphite group represented by PO(OR ₅ ) ₂ . However, in the formula, Y is a halogen atom, and R ₄ and R ₅ each represent an alkyl group or an aryl group. ) Also, the general formula ( Ia) or
The compound represented by (Ib) is represented by the following general formulas (IV) and (V)
It can also be synthesized by condensing the compound represented by.

[0018]

[Chemical 6]

(wherein R ₁ , R _{2 and} R ₃ have the same meanings as in (I), Z ₁ ,
X is synonymous with (III). ) As the reaction solvent in the above method, for example, hydrocarbons, alcohols and ethers are preferable, and methanol, ethanol, iso-propyl alcohol, butanol, 2-methoxyethanol, 1,2-dimethoxyethane, bis(2-methoxyethyl )ether,
dioxane, tetrahydrofuran, toluene, xylene, dimethylsulfoxide, N,N-dimethylformamide, N-methylpyrrolidone, 1,3-dimethyl-2-
and imidazolidinone. Polar solvents, among others
For example, N,N-dimethylformamide and dimethylsulfoxide are suitable.

As condensing agents, caustic soda, caustic potash, sodium amide, sodium hydrogen, and alcoholates such as sodium methylate and potassium-ter-butoxide are used.

[0021] The reaction temperature is also from about 0°C to about 100°C, preferably from 10°C to 80°C, and can be selected over a wide range.

The distyryl compounds represented by the general formula ( Ia) or (Ib) are structurally characterized by being asymmetrical about the nitrogen atom. Since crystallization can be suppressed in the binder, it exhibits good compatibility with the binder. Furthermore, the distyryl compound has a cyclic structure and is particularly effective against ozone deterioration.

The general formula used in the photoreceptor of the present invention is shown below.
Distyryl compounds represented by ( Ia) or (Ib) are specifically shown as compounds, but are not limited thereto.

[0024]

[Chemical 7]

[0025]

[Chemical 8]

[0026]

[Chemical 9]

[0027]

[Chemical 10]

[0028]

[Chemical 11]

[0029]

[Chemical 12]

[0030]

[Chemical 13]

[0031]

[Chemical 14]

[0032]

[Chemical 15]

[0033]

[Chemical 16]

Although the distyryl compound is a photoconductive material, it acts as a charge transport material and very efficiently transports charge carriers generated by absorbing light.

By forming a photosensitive layer containing one or more of the above distyryl compounds on a conductive support, the photoreceptor of the present invention having high sensitivity and excellent ozone resistance can be provided. As its form, for example, FIGS.
The one shown in FIG. 5 can be mentioned.

For example, a conductive support 1 as shown in FIG.
A function-separated laminated photoreceptor in which a charge generating layer 5 containing a photoconductive material 2 and a charge transporting layer 6 containing a charge transporting material 3 are laminated in this order thereon, or as shown in FIG. It is a function-separated laminated photoreceptor in which a charge transport layer 6 containing a charge transport material 3 and a charge generating layer 5 containing a photoconductive material 2 are laminated in order on a conductive support 1 . As shown in FIG. 3, the photosensitive layer formed on the conductive support 1 is a single-layer photoreceptor in which the photosensitive layer 4 is formed by blending the photoconductive material 2 and the charge transport material 3 together with a binder. , and Figure 4
As shown in FIG. 3, the photoreceptor surface is provided with a surface protective layer 7, and as shown in FIG.
An intermediate layer 8 may be provided between them.

First, the case of producing a laminated photoreceptor as shown in FIG. 1 as the photoreceptor of the present invention will be described. In this case, the photoconductive material is vacuum-deposited on the conductive support, or dissolved in a solvent such as amine and coated, or the pigment is dissolved in an appropriate solvent or, if necessary, in a binder resin. A coating liquid prepared by dispersing it in a solution is coated and dried to form a charge generation layer, and further,
A charge transport layer is formed by coating and drying a solution containing the distyryl compound of the present invention represented by formula (I) and a binder resin. For vacuum deposition, phthalocyanines such as metal-free phthalocyanine, titanyl phthalocyanine, and aluminum chlorophthalocyanine are used. For dispersion, for example, a bisazo pigment is used. At this time, the proportion of the distyryl compound in the charge transport layer is 0.02 to 2 parts by weight, preferably 0.03 to 1.3 parts by weight, per 1 part by weight of the binder resin. 3-30 μm, preferably 5
˜20 μm is desirable. The film thickness of the charge generating layer is 4 μm or less, preferably 2 μm or less.

It has been confirmed that such a function-separated laminated photoreceptor has a sufficient charge retention capacity, a low dark decay rate which is practically acceptable, and an excellent sensitivity. In addition, the value of the half decay exposure is sufficiently smaller than that of a single-layer type photoreceptor, and the distyryl compound is particularly effective as a charge transport material for a laminated photoreceptor.

As a photoreceptor in the present invention, a case of producing a single layer type photoreceptor as shown in FIG. 2 will be described.

In this case, fine particles of a photoconductive material are dispersed in a solution in which a distyryl compound and a binder resin are dissolved, and the dispersion is coated on a conductive support and dried to form a photosensitive layer to produce a photoreceptor. . At this time, the mixing ratio of the distyryl compound in the photosensitive layer is desirably 0.01 to 2 parts by weight, preferably 0.05 to 1 part by weight, per 1 part by weight of the binder resin in the photosensitive layer. When the amount of the photoconductive material relative to the binder resin in the photosensitive layer is small, sufficient sensitivity cannot be obtained, and when it is large, problems such as poor charging and weak mechanical strength of the photosensitive layer occur. 0.01 to 2 parts by weight per 1 part by weight of the binder resin in the photosensitive layer,
Preferably, 0.2 to 1.2 parts by weight is blended. The film thickness of the photosensitive layer is usually 3 to 30 µm, preferably 5 to 2 µm.
0 μm is preferable.

The single-layer type photoreceptor as described above has a sufficient charge retention capacity as compared with conventional ones, a small dark decay rate which poses no problem in practical use, and a high sensitivity.

Further, the photoreceptor of the present invention may be provided with an intermediate layer as shown in FIG. It is possible to improve the charge injection property to the photosensitive layer.

Suitable materials for the intermediate layer include polyimide, polyamide, nitrocellulose polyvinyl butyral, polyvinyl alcohol, and aluminum oxide.

Further, the photoreceptor of the present invention may be provided with a surface protective layer. Materials used for the surface protective layer include polymers such as acrylic resins, polyaryl resins, polycarbonate resins, and urethane resins.
Alternatively, a material in which a low resistance compound such as tin oxide or indium oxide is dispersed is suitable.

Organic plasma polymerized films can also be used. The organic plasma polymerized film is appropriately oxygenated as necessary,
Nitrogen, halogen, and Group 3 and Group 5 atoms of the periodic table may be included.

As the conductive support for use in the photoreceptor of the present invention, a sheet or drum of a foil or plate of copper, aluminum, iron, nickel or the like is used. These metals may also be vacuum deposited or electrolessly plated on a plastic film or the like, or a layer of a conductive compound such as a conductive polymer, indium oxide or tin oxide may be coated on a support such as paper or plastic film. It is provided by coating or vapor deposition.

Photoconductive materials used in the photoreceptor of the present invention include, for example, bisazo pigments, triarylmethane dyes, thiazine dyes, oxazine dyes, xanthene dyes, cyanine dyes, styryl dyes, Organic substances such as pyrylium-based dyes, azo-based dyes, quiacdrine-based dyes, indigo-based pigments, perylene-based pigments, polycyclic quinone-based pigments, bisbenzimidazole-based pigments, indathron-based pigments, squarylium-based pigments, and phthalocyanine-based pigments, Inorganic substances such as selenium, selenium/tellurium, selenium/arsenic, cadmium sulfide, and amorphous silicon can be used. In addition, any material can be used as long as it absorbs light and generates charge carriers with extremely high efficiency.

The binder resins used in the manufacture of photoreceptors such as those described above are electrically insulating and have a 1×
It is desirable to have a volume resistivity of 10 ¹² Ω·cm or more. For example, binders such as thermoplastic resins, thermosetting resins, photosetting resins, and photoconductive resins known per se can be used. Specifically, saturated polyester resins, polyamide resins, acrylic resins, ethylene-vinyl acetate resins, ionically crosslinked olefin copolymers (ionomers),
Thermoplastic resins such as styrene-butadiene block copolymers, polycarbonates, vinyl chloride-vinyl acetate copolymers, cellulose esters, polyimides, and styrene resins; epoxy resins, urethane resins, silicone resins, phenol resins, melamine resins, xylene resins, Thermosetting resins such as alkyd resins and thermosetting acrylic resins; photocurable resins; polyvinylcarbazole, polyvinylpyrene,
Photoconductive resins such as polyvinylanthracene and polyvinylpyrrole may be used, and these binder resins may be used alone or in combination of two or more.

When the charge transport material itself is a polymeric charge transport material that can be used as a binder, it is not necessary to use other binder resins.

The photoreceptor of the present invention contains a binder resin together with a plasticizer such as halogenated paraffin, polychlorinated biphenyl, dimethylnaphthalene, dibutylphthalate, O-terphenyl, chloranil, tetracyanoethylene, 2,
Electron-withdrawing sensitizers such as 4,7-trinitrofluorenone, 5,6-dicyanobenzoquinone, tetracyanoquinodimethane, tetrachlorophthalic anhydride, 3,5-dinitrobenzoic acid, methyl violet, rhodamine B, cyanine dyes , pyrylium salts, thiapyrylium salts and the like may be used.

[0051]

[Synthesis example] Synthesis examples of the distyryl compound represented by the compound example (10) are shown below.

The following formula:

[0053]

[Chemical 17]

3.89 g of an aldehyde compound represented by
and the following formula:

[0055]

[Chemical 18]

3.3 g of the phosphonate compound represented by ##STR3## was dissolved in 100 ml of dimethylformamide. A suspension containing 1.5 g of potassium-ter-butoxide in 70 ml of dimethylformamide was added dropwise to the obtained solution while cooling to 5° C. or below, and the mixture was stirred at room temperature for 8 hours and then allowed to stand overnight. The resulting mixture was purged into 900 ml of ice water and then neutralized with dilute hydrochloric acid. After about 1 hour, precipitated crystals were filtered, and the filtered product was washed with water, dissolved in toluene, and separated and purified by silica gel column chromatography.

After removing toluene from the effluent, recrystallization from acetonitrile gave 4.4 g of yellow crystals (yield 78%).
got

The results of elemental analysis are as follows.

[0059]

[Table 1]

[0060]

EXAMPLES The distyryl compounds of the present invention used in the following examples were synthesized according to the above synthesis examples or similar methods.

Example 1

[0062]

[Chemical 19]

0.45 parts by weight of the disazo compound represented by the general formula (VI), a polyester resin (Vylon 200,
Toyobo Co., Ltd.) 0.45 parts by weight of cyclohexanone 5
It was dispersed with a sand mill along with 0 parts by weight. The dispersion of the disazo compound thus obtained was applied to aluminized Mylar having a thickness of 100 μm using a film applicator so as to give a dry film thickness of 0.3 g/m ² and then dried to form a charge generation layer. 50 parts by weight of the distyryl compound (1) and polycarbonate (Panlite K-130) were added thereto.
0, manufactured by Teijin Chemicals Co., Ltd.) dissolved in 400 parts by weight of 1,4-dioxane was applied to a dry film thickness of 16 μm and dried to form a charge transport layer.
A photoreceptor having a photosensitive layer consisting of two layers was produced.

The photoreceptor thus prepared was transferred to a commercially available electrophotographic copier (EP-450Z manufactured by Minolta Camera Co., Ltd.).
In-charged by a corona discharge of 6 Kv, the initial surface potential V ₀ (v), the exposure required for the surface potential to decay to half of the initial surface potential (hereinafter referred to as half-exposure) E
The decay rate DDR ₁ (%) of the initial potential when left in the dark for _1/2 (Lux·sec) for 1 second was measured. Table 2 shows the results.

Examples 2 and 3 Two kinds of laminated photoreceptors were prepared in the same manner as in Example 1 except that the distyryl compounds (2) and (3) were used in place of the distyryl compound (1) used in Example 1. was made. V ₀ , E _1/2 , and DDR ₁ were measured in the same manner as in Example 1 for each photoreceptor.
was measured and the results are shown in Table 2.

Example 4

[0067]

[Chemical 20]

0.45 parts by weight of the disazo compound represented by the general formula (VII), polystyrene resin (molecular weight: 4000
0) 0.45 parts by weight was dispersed with 50 parts by weight of cyclohexanone using a sand mill. The obtained dispersion of the disazo compound was applied to a 100 μm thick aluminized mylar using a film applicator to give a dry film thickness of 0.3 g/mm.
After coating to a thickness of m ² , it was dried to form a charge generation layer. On top of this, 50 parts by weight of distyryl compound (4) and 50 parts of polyarylate resin (U-100, manufactured by Unitika Ltd.) were added.
A photoreceptor having a two-layered photosensitive layer is formed by coating a solution of 400 parts by weight of 1,4-dioxane in a dry film thickness of 20 μm and drying to form a charge transport layer. was made. V ₀ , E _1/2 , and DDR ₁ of this photoreceptor were measured in the same manner as in Example 1, and the results are shown in Table 2.
shown in

Examples 5 and 6 Two kinds of laminated photoreceptors were prepared in the same manner as in Example 4 except that the distyryl compounds (5) and (6) were used in place of the distyryl compound (4) used in Example 4 . was made. V ₀ , E _1/2 , and DDR ₁ were measured in the same manner as in Example 1 for each photoreceptor.
was measured and the results are shown in Table 2.

Example 7

[0071]

[Chemical 21]

0.45 parts by weight of the polycyclic quinone pigment represented by the general formula (VIII), polycarbonate (Panlite K
-1300, manufactured by Teijin Chemicals Co., Ltd.) was dispersed with 50 parts by weight of dichloroethane by a sand mill. The polycyclic quinone-based pigment dispersion thus obtained was
A film applicator was used to coat a 0.4 g/ ^m.sup.2 dry film on aluminized mylar of 1.5 m and then dried to form a charge generation layer. 60 parts by weight of distyryl compound (9) and polyarylate resin (U-10)
0, manufactured by Unitika Ltd.) dissolved in 400 parts by weight of 1,4-dioxane was applied to a dry film thickness of 18 μm and dried to form a charge transport layer.
A photoreceptor having a photosensitive layer consisting of two layers was produced. V ₀ , E _1/2 , and DD of this photoreceptor were measured in the same manner as in Example 1.
R ₁ was measured and the results are shown in Table 2.

[0073] Furthermore, the photoreceptor described above can be used with a commercially available electrophotographic copier (EP-350Z manufactured by Minolta Camera Co., Ltd.).
Repeated actual photography was performed during negative charging. Even after 1,000 shots were taken, the gradation was excellent in the final image as well as in the initial stage, there was no change in sensitivity, and a clear image was obtained. was done.

Examples 8-9 Two kinds of laminated photoreceptors were prepared in the same manner as in Example 7 except that the distyryl compounds (11) and (12) were used in place of the distyryl compound (9) used in Example 7 . was made. V ₀ , E _1/2 , DD for each photoreceptor were measured in the same manner as in Example 1.
R ₁ was measured and the results are shown in Table 2.

Example 10

[0076]

[Chemical 22]

0.45 parts by weight of the perylene pigment represented by the general formula (IX) and 0.45 parts by weight of a butyral resin (BX-1, manufactured by Sekisui Chemical Co., Ltd.) were mixed with 50 parts by weight of dichloroethane in a sand mill. dispersed. The resulting perylene pigment dispersion was applied to aluminized mylar having a thickness of 100 μm using a film applicator so that the dry film thickness was 0.4 g/m ² , and then dried to form a charge generation layer. . A solution prepared by dissolving 50 parts by weight of distyryl compound (16) and 50 parts by weight of polycarbonate resin (PC-Z, manufactured by Mitsubishi Gas Chemical Co., Ltd.) in 400 parts by weight of 1,4-dioxane was applied thereon to give a dry film thickness of 18 μm. and dried to form a charge transport layer, thereby producing a photoreceptor having a two-layered photosensitive layer. V ₀ , E _1/2 and DDR ₁ of this photoreceptor were measured in the same manner as in Example 1, and the results are shown in Table 2.

Examples 11 and 12 The distyryl compounds (17) and (21) were used in place of the distyryl compound (16) used in Example 10 .
Two types of laminated photoreceptors were produced in the same manner as in No. 10 . V ₀ ,
E _1/2 and DDR ₁ were measured and the results are shown in Table 2.

Example 13 0.45 parts by weight of titanyl phthalocyanine pigment and 0.45 parts by weight of butyral resin (PC-Z, manufactured by Mitsubishi Gas Chemical Co., Ltd.) were dispersed together with 50 parts by weight of dichloroethane by a sand mill. The resulting dispersion of titanyl phthalocyanine pigment was applied to aluminized Mylar having a thickness of 100 μm using a film applicator so that the dry film thickness would be 0.3 g/m ² and then dried to form a charge generation layer. . 50 parts by weight of distyryl compound (25) and 50 parts of polycarbonate resin (PC-Z, manufactured by Mitsubishi Gas Chemical Co., Ltd.) were added thereon.
A photoreceptor having a two-layered photosensitive layer is formed by applying a solution of 400 parts by weight of 1,4-dioxane to a dry film thickness of 18 μm and drying to form a charge transport layer. was made. V ₀ , E _1/2 , and DDR ₁ of this photoreceptor were measured in the same manner as in Example 1, and the results are shown in Table 2.
shown in

Example 14 A laminated photoreceptor was prepared in the same manner as in Example 13 except that the distyryl compound (25) used in Example 13 was replaced with the distyryl compound (26) . V ₀ , E _1/2 and DDR ₁ were measured for each photoreceptor in the same manner as in Example 1, and the results are shown in Table 2.

Example 15 0.45 parts by weight of copper phthalocyanine and 0.2 parts by weight of tetranitrocopper phthalocyanine were dissolved in 500 parts by weight of 98% concentrated sulfuric acid with thorough stirring. This was mixed with 5000 parts by weight of water to precipitate a photoconductive material composition of copper phthalocyanine and tetracopper phthalocyanine, filtered, washed with water and dried at 120° C. under reduced pressure. 10 parts by weight of the photoconductive composition thus obtained was added to 2 of a thermosetting acrylic resin (Acrydic A-405, manufactured by Dainippon Ink Co., Ltd.).
2.5 parts by weight, melamine resin (Super Beckamin J8
20. Dainippon Ink Co., Ltd.) 7.5 parts by weight and 15 parts by weight of distyryl compound (28) were placed in a ball mill pot together with 100 parts by weight of a solvent obtained by mixing equal amounts of methyl ethyl ketone and xylene, and dispersed for 48 hours. A flexible coating liquid was prepared. This coating liquid was coated on an aluminum support and dried to form a photosensitive layer having a thickness of 15 μm to prepare a single-layer photoreceptor.

[0082] The photoreceptor prepared in this way is transferred to a commercially available electrophotographic copier (EP-450Z manufactured by Minolta Camera Co., Ltd.).
The V ₀ , E _1/2 , and DDR ₁ were measured in the same manner as in Example 1, except that they were charged by +6 Kv corona discharge.

Examples 16 to 18 Three different compounds were prepared in the same manner as in Example 15 except that the distyryl compounds (29), (31) and (32) were used in place of the distyryl compound (28) used in Example 15 . A photoreceptor was produced. V ₀ ,
E _1/2 and DDR ₁ were measured and the results are shown in Table 3.

Comparative Examples 1 to 4 The following distyryl compounds (1-1), (1-2) and (1) were used in place of the distyryl compound (28) used in Example 15 .
-3) and (1-4) were used in the same manner as in Example 15 to prepare four kinds of single-layer photoreceptors. V ₀ , E _1/2 , and DDR ₁ were measured in the same manner as in Example 1 except that each photosensitive member was charged by +6 kV corona discharge.

[0085]

[Chemical 23]

Comparative Examples 5 to 7 Instead of the distyryl compound (28) used in Example 15 , the following distyryl compounds (1-5), (1-6) and (1) were used.
-7) was used to prepare three types of single-layer photoreceptors in the same manner as in Example 15 . V ₀ , E _1/2 , and DDR ₁ were measured in the same manner as in Example 1 except that each photosensitive member was charged by +6 kV corona discharge.

[0087]

[Chemical 24]

[0088]

[Table 2]

[0089]

[Table 3] (Continued from Table 2)

[0090]

EFFECTS OF THE INVENTION The photoreceptor of the present invention has an excellent charge transport property, a sufficiently small dark decay rate, a good charging property, and a carrier Therefore, it was possible to provide a photoreceptor with less traps and high sensitivity.

[Brief description of the drawing]

FIG. 1 is a schematic cross-sectional view of a photoreceptor according to the present invention in which a charge generation layer and a charge transport layer are laminated on a conductive support;

FIG. 2 is a schematic cross-sectional view of a photoreceptor according to the present invention in which a charge transport layer and a charge generation layer are laminated on a conductive support;

FIG. 3 is a schematic cross-sectional view of a photoreceptor according to the present invention having a photosensitive layer on a conductive support;

FIG. 4 is a schematic cross-sectional view of a photoreceptor according to the present invention in which a surface protective layer is provided on the surface of a single-layer photoreceptor;

FIG. 5 is a schematic cross-sectional view of a photoreceptor according to the present invention in which an intermediate layer is provided between a conductive support and a photosensitive layer;

[Description of symbols]

1 conductive support 2 Photoconductive material 3 charge transport material 4 photosensitive layer 5 charge generation layer 6 charge transport layer 7 surface protective layer 8 middle layer

Claims (1)

(57) [Claims] [Claim 1] On a conductive support, the following general formula (Ia) or
or (Ib) containing a distyryl compound. [Chemical Formula 1a] (In the formula, R _{1 and} R ₂ are independently a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom; R ₃ is an optionally substituted alkyl group, aralkyl group, aryl group, condensed polycyclic represents a formula group or a composite ring group Ar _{1 ,} Ar ₂
each independently represents a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group or a condensed polycyclic group which may each have a substituent. Z ₁ is fused with a benzene ring, carbon and oxygen to give
the heterocycle or benzene ring formed, carbon and sulfur and
The heterocyclic ring formed by condensation may have a substituent. ) [Chemical 1b] (wherein R _{1 ,} R ₂ , R ₃ , Ar ₁ and Ar ₂ are (Ia) and
Same. Z2 is formed by condensation with a benzene ring and _carbon
The condensed ring may have a substituent. provided that R ₃ is a substituent
when Ar ₁ and Ar ₂ are phenyl groups optionally having
A phenyl group, each of which may independently have a substituent,
When taking either a phthyl group or a heterocyclic group at the same time
except for. )