JP2861297B2 - Photoconductor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a photoreceptor having a photosensitive layer containing a novel distyryl compound.

2. Description of the Related Art In general, in electrophotography, an electrostatic latent image is formed by charging and exposing the surface of a photosensitive layer of a photoreceptor, developing the latent image with a developer, and visualizing the latent image. A direct method in which a copy image is obtained by fixing the image on the surface, a powder image transfer method in which the visible image on the photoconductor is transferred onto a transfer material such as paper, and the transferred image is fixed to obtain a copy image. A latent image transfer method for transferring an electrostatic latent image on a transfer sheet and developing and fixing the electrostatic latent image on the transfer sheet is known.

As a material constituting a photosensitive layer of a photoreceptor used in this type of electrophotography, conventionally, selenium, cadmium sulfide,
Inorganic photoconductive materials such as zinc oxide are known.

These photoconductive materials have a number of advantages, such as less charge dissipation in a dark place, or the ability to quickly dissipate charge by light irradiation, but have various disadvantages. For example, in a selenium-based photoconductor,
The manufacturing conditions are difficult, the manufacturing cost is high, and care is required for handling because it is weak against heat and mechanical shock. Cadmium sulfide photoreceptors and zinc oxide photoreceptors do not provide stable sensitivity in humid environments, and dyes added as sensitizers cause charge deterioration due to corona charging and photobleaching due to exposure, resulting in long-term However, there is a disadvantage that stable characteristics cannot be provided over a wide range.

On the other hand, various organic photoconductive polymers such as polyvinyl carbazole have been proposed, but these polymers are more capable of forming a film than the above-mentioned inorganic photoconductive materials.
Although excellent in lightness and the like, it is still inferior to inorganic photoconductive materials in sufficient sensitivity, durability and stability due to environmental changes.

The low molecular weight organic photoconductive compound is preferable in that the physical properties or electrophotographic properties of the coating can be controlled by selecting the type and composition ratio of the binder used in combination. Since it is used together with the binder, high compatibility with the binder is required.

A photoreceptor in which these high molecular weight and low molecular weight organic photoconductive compounds are dispersed in a binder resin has drawbacks such as a large residual potential due to many carrier traps and low sensitivity. Therefore, it has been proposed to solve the above-mentioned drawbacks by blending a charge transport material with a photoconductive compound.

Also, a function-separated type photoreceptor has been proposed in which the charge generation function and the charge transport function of the photoconductive function are shared by different substances. In such a function-separated type photoreceptor, many organic compounds are listed as the charge transporting material used for the charge transporting layer, but there are various problems in practice. For example, 2,5-bis (P-diethylaminophenyl) 1,3,4-oxadiazole described in U.S. Pat. No. 3,189,447 has low compatibility with a binder and tends to precipitate crystals. U.S. Patent 3,820,989
The diarylalkane derivative described in Japanese Patent Application Laid-Open Publication No. H08-27139 has good compatibility with a binder, but changes in sensitivity when used repeatedly. In addition, the hydrazone compound described in JP-A-54-59143 has a relatively good residual potential characteristic, but has a drawback of poor charging ability and repetition characteristics.

As described above, in reality, there is almost no low-molecular-weight organic compound having practically preferable characteristics in producing a photoreceptor.

Incidentally, as a compound having excellent charge transporting ability, distyryl compounds are disclosed in JP-A-60-175052 and JP-A-62-120346.
However, the chemical structure is completely different from the compounds disclosed in the present application.

An object of the present invention is to contain a distyryl compound having excellent compatibility with a binder and charge transporting ability, high sensitivity and excellent charging ability, less fatigue deterioration when used repeatedly, and stable electrophotographic properties. The purpose is to provide a photoreceptor that is

Problems to be Solved by the Invention The present invention has been made in view of the above facts, and it is an object of the present invention to provide a photoreceptor having excellent electrostatic characteristics in general and particularly excellent sensitivity.

Means for Solving the Problems The present invention relates to a photoconductor in which a photosensitive layer containing a distyryl compound represented by the general formula [I] is provided on a conductive support; In the general formula [I], Ar ₁ and Ar ₂ independently represent a lower alkyl group such as methyl and ethyl, and an aryl group such as phenyl, tolyl and naphthyl, and these groups include alkyl, alkoxy, hydroxy and dialkyl. It may have a substituent such as a substituted amino group or a halogen atom.

Ar ₃ represents a lower alkyl group such as a methyl group, an aralkyl group such as benzyl, or an aryl group such as phenyl, and these groups may have a substituent such as an alkyl group, an alkoxy group, or a halogen atom.

R ₁ and R ₂ independently represent a hydrogen atom, an alkyl group such as methyl,
It represents an alkoxy group such as a methoxy group or an ethoxy group, or a halogen atom such as chlorine.

R ₃ represents a hydrogen atom, an alkyl group such as methyl or ethyl, an alkenyl group such as a thienyl group, a furyl group, a pyrrole group, a pyridyl group, an aralkyl group, an ethenyl group, or an alkynyl group such as an ethynyl group.

The distyryl compound represented by the general formula [I] has a structural characteristic of being asymmetric around a nitrogen atom, and gives good results in photoreceptor characteristics such as solubility in a resin, sensitivity, and repetition characteristics. .

Preferred specific examples of the distyryl compound represented by the general formula [I] of the present invention include those having the following structural formulas, but are not limited thereto.

The compound represented by the general formula [I] of the present invention can be easily synthesized by a usual method.

 That is, the aldehyde compound represented by the general formula [II]
Things [Wherein, Ar_Three, R₁~ R_ThreeHas the same meaning as [I].] The following general formula [III]: [Where X is -P R_Four)_ThreeY Tria represented by
Alkyl or triarylphosphonium group, or PO (O
R_Five)_TwoDialkyl or diaryl phosphite represented by
Wherein Y is a halogen atom, R_Four, R_FiveAre each
An alkyl group or an aryl group)].
Can be

The compound represented by the general formula [I] can also be synthesized by condensing the compounds represented by the general formulas [IV] and [V].

[Wherein, Ar ₁ , Ar ₂ , Ar ₃ , R ₁ , R ₂ , and R ₃ have the same meaning as [I] and X has the same meaning as [III]].

As the reaction solvent in the above method, for example, hydrocarbons, alcohols, ethers are good, methanol,
Ethanol, isopropanol, butanol, 2-methoxyethanol, 1,2-dimethoxyethane, bis (2-
Methoxyethyl) ether, dioxane, tetrahydrofuran, toluene, xylene dimethyl sulfoxide, N,
N-dimethylformamide, N-methylpyrrolidone, 1,3
-Dimethyl-2-imidazolidinone and the like.
Among them, polar solvents such as N, N-dimethylformamide and dimethyl sulfoxide are preferred.

Caustic soda, potassium hydroxide, sodium amide, sodium hydrogen and sodium methylate, and alcoholates such as potassium ter-butoxide are used as the condensing agent.

The reaction temperature can be selected over a wide range from about 0 ° C to about 100 ° C. Preferably it is 10 ° C to about 80 ° C.

The photoreceptor of the present invention has a photosensitive layer containing one or more distyryl compounds represented by the general formula [I].

Various types of photoconductors are known, but the photoconductor of the present invention may be any of those photoconductors. For example, a charge-generating material on a support, a single-layer photoreceptor having a photosensitive layer formed by dispersing a distyryl compound in a resin binder,
There is a so-called laminated photoreceptor in which a charge generation layer mainly containing a charge generation material is provided on a support, and a charge transport layer is provided thereon. Although the distyryl compound of the present invention is a photoconductive substance, it acts as a charge transporting material and can transport charge carriers generated by absorbing light extremely efficiently.

In order to produce a single-layer photoreceptor, the fine particles of the charge generating material may be dispersed in a resin solution or a solution in which a charge transport compound and a resin are dissolved, and the dispersion may be applied on a conductive support and dried. At this time, the thickness of the photosensitive layer is 3 to 30 μm,
Preferably, it is 5 to 20 μm. If the amount of the charge generating material used is too small, the sensitivity is poor, and if it is too large, the chargeability is deteriorated, the mechanical strength of the photosensitive layer is reduced, and the proportion in the photosensitive layer is 1 part by weight of the resin. 0.01 to 2 parts by weight, preferably 0.2 to 1.2 parts by weight.

To produce a laminated photoreceptor, a charge generation material is vacuum-deposited on a conductive support, or dissolved in a solvent such as an amine and applied, or a pigment is applied to a suitable solvent or a binder if necessary. It is obtained by applying and drying a coating solution prepared by dispersing in a solution in which a resin is dissolved, and then applying and drying a solution containing a charge transport material and a binder thereon. In the case of performing vacuum deposition, for example, phthalocyanines such as metal-free phthalocyanine, titanyl phthalocyanine, and aluminum chlorophthalocyanine are used. When dispersing, for example, a bisazo pigment is used. At this time, the thickness of the charge generation layer is 4 μm or less, preferably 2 μm or less, and the thickness of the charge transport layer is 3 to 30 μm.
m, preferably 5 to 20 μm.

The ratio of the charge transporting material in the charge transporting layer is 0.2 to 2 parts by weight, preferably 0.3 to 1.
3 parts by weight.

The photoreceptor of the present invention, together with a binder resin, a plasticizer such as halogenated paraffin, polychlorinated biphenyl, dimethylnaphthalene, dibutylphthalate, and O-terphenyl, chloranil, tetracyanoethylene, 2,4,7-trinitrofluorenone, 5 , 6-dicyanobenzoquinone, tetracyanoquinodimethane, tetrachlorophthalic anhydride,
Electron withdrawing sensitizers such as 3,5-dinitrobenzoic acid, and sensitizers such as methyl violet, rhodamine B, cyanine dyes, pyrylium salts, and thiapyrylium salts may be used.
Further, an antioxidant, an ultraviolet absorber, a dispersing aid, an anti-settling agent, a leveling agent, and the like may be appropriately used. Another charge transporting material such as hydrazone may be used in combination with the distyryl compound of the present invention.

As the electrically insulating binder resin used in the present invention, a binder such as a thermoplastic resin or a thermosetting resin, a photocurable resin, or a photoconductive resin known per se, which is electrically insulating, can be used. . Examples of suitable binder resins are
Although not limited thereto, saturated polyester resin, polyamide resin, acrylic resin, ethylene-vinyl acetate resin, ion-crosslinked olefin copolymer (ionomer), styrene-butadiene block copolymer, polycarbonate, vinyl chloride-acetic acid Thermoplastic resins such as vinyl copolymers, cellulose esters, polyimides, and styrene resins; thermosetting resins such as epoxy resins, urethane resins, silicone resins, phenolic resins, melamine resins, xylene resins, alkyd resins, and thermosetting acrylic resins;
Photocurable resin; a photoconductive resin such as polyvinylcarbazole, polyvinylpyrene, polyvinylanthracene, and polyvinylpyrrole.

These can be used alone or in combination.

These electrically insulating resins were measured independently to obtain 1 × 10 ¹² Ω
It is desirable to have a volume resistance of at least cm.

As the charge generating material, bisazo pigments, triarylmethane dyes, thiazine dyes, oxazine dyes,
Xanthene dyes, cyanine dyes, styryl dyes,
Pyrylium dyes, azo pigments, quinacridone pigments,
Indigo pigments, perylene pigments, polycyclic quinone pigments,
Bisbenzimidazole pigments, indathrone pigments,
Organic substances such as squarium salt pigments, azulene pigments, phthalocyanine pigments, and inorganic substances such as selenium, selenium alloys such as selenium, tellurium, selenium and arsenic, cadmium sulfide, cadmium selenide, zinc oxide, and amorphous silicon. Can be In addition, any material that absorbs light and generates charge carriers at an extremely high probability can be used.

As the conductive support used in the photoreceptor of the present invention,
Copper or aluminum, silver, iron, nickel or other metal foil or plate is used in the form of a sheet or drum,
Alternatively, these metals are vacuum-deposited or electroless-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 is coated on a support such as paper or a plastic film. Alternatively, one provided by vapor deposition is used.

Examples of the constitution of a photoreceptor using the distyryl compound of the present invention are schematically shown in FIGS.

FIG. 1 shows a photoconductor in which a photosensitive layer (4) in which a photoconductive material (3) and a charge transport material (2) are mixed with a binder is formed on a substrate (1). The distyryl compound of the present invention is used.

FIG. 2 shows a function-separated type photoreceptor having a charge generation layer (6) as a photosensitive layer and a charge transport layer (5). The charge transport layer (5) is formed on the surface of the charge generation layer (6). ing.

The distyryl compound of the present invention is blended in the charge transport layer (5).

FIG. 3 shows a function-separated type photoreceptor having a charge generation layer (6) and a charge transport layer (5) as in FIG.
Contrary to the figure, the charge generation layer (6) is provided on the surface of the charge transport layer (5).
Are formed.

FIG. 4 shows that the surface protective layer (7) is further provided on the surface of the photoreceptor of FIG. 1, and the photosensitive layer (4) has a charge generation layer (6) and a charge transport layer (5). A function-separated type photoconductor may be used.

FIG. 5 shows that an intermediate layer (8) is provided between the substrate (1) and the photosensitive layer (4). The intermediate layer (8) has improved adhesion, improved coating properties, and protected the substrate. For improving the charge injection property from the substrate to the photosensitive layer.

As the material used for the intermediate layer, polyimide, polyamide, nitrocellulose, polyvinyl butyral, polyvinyl alcohol, aluminum oxide and the like are appropriate,
The thickness is desirably 1 μm or less.

As a material used for the surface protective layer, a polymer such as an acrylic resin, a polyaryl resin, a polycarbonate resin, or a urethane resin as it is, or a material in which a low-resistance compound such as tin oxide or indium oxide is dispersed is suitable.

Also, an organic plasma polymerized film can be used. The organic plasma polymerized film may optionally contain oxygen, nitrogen, halogen, and atoms of Groups 3 and 5 of the Periodic Table as appropriate.

 The thickness of the surface protective layer is desirably 5 μm or less.

Synthesis Example 1 (Synthesis of Compound [2]) A solution obtained by dispersing 2.24 g of potassium ter-butoxide in 50 ml of dimethylformamide was cooled to 5 ° C. or lower, and the solution was stirred with the following formula: Aldevide 4.51 g and ethyltriphenylphosphonium bromide 3.71 g represented by dimethylformamide 100 ml
The solution dissolved in the above was gradually dropped in a nitrogen stream under cooling.

Then, after stirring at room temperature for 4 hours, the reaction was carried out at 80 ° C. for 30 minutes to complete the reaction.

The obtained mixture was added to 500 ml of ice water, neutralized with dilute hydrochloric acid, and after about 30 minutes, the precipitated crystals were filtered. The filtered product was washed with water, dissolved in benzene, and separated and purified by silica gel column chromatography.

After distilling off benzene from the effluent, recrystallization from acetonitrile gave 3.0 g (yield 65%) of pale yellow crystals.

Melting point (mp) 56-58 ° C The results of elemental analysis are as follows.

Synthesis Example 2 (Synthesis of Compound [11]) And 4.51 g of aldebid represented by the following formula: Was dissolved in 60 ml of dimethylformaldehyde, and while cooling to 5 ° C., a suspension containing 1.68 g of potassium ter-butoxide in 50 ml of dimethylformamide was gradually added dropwise. Thereafter, the mixture was stirred at room temperature for 2 hours, and reacted at 80 ° C. for 1 hour to complete the reaction.

The obtained mixture was added to 500 ml of ice water, neutralized with dilute hydrochloric acid, and after about 30 minutes, the precipitated crystals were filtered. The filtered product was washed with water, dissolved in benzene / hexane, and separated and purified by silica gel column chromatography.

After distilling off the benzene / hexane from the effluent, recrystallization from acetonitrile gave 3.7 g (yield 72%) of pale yellow crystals.

Melting point (mp) 67-68 ° C The results of elemental analysis are as follows.

Hereinafter, the present invention will be described with reference to examples. In the examples, “parts” means “parts by weight” unless otherwise specified.

Example 1 Bisazo compound represented by the following general formula [A] 0.45 part and 0.45 part of a polyester resin (byron 200 manufactured by Toyobo Co., Ltd.) were dispersed together with 50 parts of cyclohexanone by a sand mill. The obtained dispersion of the bisazo compound was applied on an aluminized mylar having a thickness of 100 μm using a film applicator so that the dry film thickness became 0.3 g / m ^2, and then dried.

On the charge generation layer thus obtained, 50 parts of a bistyryl compound [2] and 50 parts of a polycarbonate resin (Panlite K-1300; manufactured by Teijin Chemicals Ltd.) were added to 1,4-dioxane.
The solution dissolved in 400 parts was applied to a dry film thickness of 16 μm and dried to form a charge transport layer. Thus, an electrophotographic photoreceptor having two photosensitive layers was obtained.

The photoreceptor obtained in this manner is used in a commercially available electrophotographic copying machine (EP
(−450Z: manufactured by Minolta Camera Co., Ltd.), corona charged at −6 Kv, initial surface potential V ₀ (V), exposure amount E _1/2 ( ₁ ux · sec) required to reduce the initial potential to を. The decay rate DDR ₁ (%) of the initial potential when left in the dark for 1 second was measured.

Examples 2 to 4 In the same manner as in Example 1, the same configuration was used, except that the distyryl compounds [3], [4], and [8] were used instead of the distyryl compound [2] used in Example 1. A photoreceptor was produced.

With respect to the photoreceptor thus obtained, V ₀ , E _1/2 , and DDR ₁ were measured in the same manner as in Example 1.

Example 5 Bisazo compound represented by the following general formula [B] 0.45 part and 0.45 part of a polystyrene resin (molecular weight: 40,000) were dispersed together with 50 parts of cyclohexanone by a sand mill.

Using a film applicator, apply the obtained dispersion of the bisazo compound onto a 100-μm-thick aluminized mylar,
The coating was applied so that the dry film thickness became 0.3 g / m ^2, and then dried.

On the charge generation layer thus obtained, 50 parts of a distyryl compound [10] and a polyarylate resin (U-100:
A solution prepared by dissolving 50 parts of Unitika in 400 parts of 1,4-dioxane was applied to a dry film thickness of 20 μm and dried to form a charge transport layer.

Thus, an electrophotographic photosensitive member having a two-layer photosensitive layer was produced.

With respect to the photoreceptor thus obtained, V ₀ , E _1/2 , and DDR ₁ were measured in the same manner as in Example 1.

Examples 6 to 8 In the same manner as in Example 5, the same configuration was used, except that the distyryl compounds [11], [14], and [16] were used instead of the distyryl compound [10] used in Example 5. A photoreceptor was produced.

With respect to the photoreceptor thus obtained, V ₀ , E _1/2 , and DDR ₁ were measured in the same manner as in Example 1.

Example 9 Polycyclic quinone pigment represented by the following general formula [C] 0.45 parts, polycarbonate resin (Panlite K-1300:
0.45 part (manufactured by Teijin Chemicals Ltd.) was dispersed with a sand mill together with 50 parts of dichloroethane.

The resulting dispersion of the polycyclic quinone pigment was applied onto an aluminized mylar having a thickness of 100 μm using a film applicator so that the dry film thickness became 0.4 g / m ^2, and then dried. On the charge generation layer thus obtained, 60 parts of a distyryl compound [17] and a polyarylate resin (U-10
A solution in which 50 parts of (0: manufactured by Unitika) was dissolved in 400 parts of 1,4-dioxane was applied so as to have a dry film thickness of 18 μm, and dried to form a charge transport layer.

Thus, an electrophotographic photoreceptor having a two-layered photosensitive layer was prepared. V ₀ , E _1/2 , and DDR ₁ were measured in the same manner as in Example 1 for the thus obtained photoreceptor.

Examples 10 to 11 Photoreceptors having the same constitution as in Example 9 but using distyryl compounds [18] and [20] instead of the distyryl compound [17] used in Example 9 were produced. did.

With respect to the photoreceptor thus obtained, V ₀ , E _1/2 , and DDR ₁ were measured in the same manner as in Example 1.

Example 12 A perylene pigment represented by the following general formula [D] 0.45 parts, butyral resin (BX-1: Sekisui Chemical Co., Ltd.)
45 parts were dispersed by a sand mill together with 50 parts of dichloroethane.

Using a film applicator on the resulting perylene-based pigment dispersion on an aluminized mylar having a thickness of 100 μm,
The coating was applied so that the dry film thickness became 0.4 g / m ^2, and then dried.
A solution obtained by dissolving 50 parts of a distyryl compound [28] and 50 parts of a polycarbonate resin (PC-Z: manufactured by Mitsubishi Gas Chemical Co., Ltd.) in 400 parts of 1,4-dioxane was obtained on the charge generation layer thus obtained. Coating was performed so that the thickness became 18 μm to form a charge transport layer.

Thus, an electrophotographic photosensitive member having a two-layer photosensitive layer was produced.

With respect to the photoreceptor thus obtained, V ₀ , E _1/2 , and DDR ₁ were measured in the same manner as in Example 1.

Examples 13 to 14 Production of photoreceptors having the same constitution in the same manner as in Example 12, except that distyryl compounds [31] and [32] are used in place of the distyryl compound [28] used in Example 12 did.

With respect to the photoreceptor thus obtained, V ₀ , E _1/2 , and DDR ₁ were measured in the same manner as in Example 1.

Example 15 0.45 part of titanyl phthalocyanine, butyral resin (BX
-1: Sekisui Chemical Co., Ltd.) was dispersed by a sand mill together with 50 parts of dichloroethane.

The dispersion of the obtained phthalocyanine pigment is 100 μm thick.
Was applied using a film applicator to a dry film thickness of 0.3 g / m ² and then dried. On the charge generation layer thus obtained, 50 parts of a distyryl compound [35] and a polycarbonate resin (PC-
A solution prepared by dissolving 50 parts of Z (manufactured by Mitsubishi Gas Chemical Company) in 400 parts of 1,4-dioxane was applied to a dry film thickness of 18 μm to form a charge transport layer.

Thus, an electrophotographic photosensitive member having a two-layer photosensitive layer was produced.

With respect to the photoreceptor thus obtained, V ₀ , E _1/2 , and DDR ₁ were measured in the same manner as in Example 1.

Examples 16 to 17 Production of photoreceptors having the same constitution as in Example 15 except that distyryl compounds [37] and [39] are used instead of the distyryl compound [35] used in Example 15 did.

With respect to the photoreceptor thus obtained, V ₀ , E _1/2 , and DDR ₁ were measured in the same manner as in Example 1.

Example 18 50 parts of copper phthalocyanine and 0.2 parts of tetranitro copper phthalocyanine were dissolved in 500 parts of 98% concentrated sulfuric acid with sufficient stirring, and the mixture was poured into 5000 parts of water to prepare a photoconductive material composition of copper phthalocyanine and tetranitro copper phthalocyanine. After the precipitation, the precipitate was filtered, washed with water, and dried at 120 ° C. under reduced pressure.

10 parts of the photoconductive composition thus obtained was mixed with a thermosetting acrylic resin (Acrydik A405: manufactured by Dainippon Ink) 22.5
Part, melamine resin (Super Beckamine J820: manufactured by Dainippon Ink Co., Ltd.) 7.5 parts, the above-mentioned distyryl compound [41] 15
Parts were mixed in a ball mill pot together with 100 parts of a mixed solvent in which methyl ethyl ketone and xylene were mixed in the same amount, and dispersed for 48 hours to prepare a photosensitive coating solution. The coating solution was applied on an aluminum substrate, dried, and dried. A photosensitive layer having a thickness of about 15 μm was formed to prepare a photosensitive member.

The photoreceptor thus obtained was subjected to the same method as in Example 1 except that corona charging was performed at +6 Kv to obtain V ₀ , E _1/2 , and DD.
It was measured R _1.

Examples 19 to 21 In the same manner as in Example 18, the same configuration was used, except that the distyryl compounds [44], [45], and [47] were used instead of the distyryl compound [41] used in Example 18. A photoreceptor was produced.

With respect to the photoreceptor thus obtained, V ₀ , E _1/2 , and DDR ₁ were measured in the same manner as in Example 1.

Comparative Examples 1 to 4 In the same manner as in Example 18, the same composition was used, except that the following compounds [E], [F], [G], and [H] were substituted for the distyryl compound used in Example 18 A photoconductor was prepared in the same manner as in Example 15 except for using it.

With respect to the photoreceptor thus obtained, V ₀ , E _1/2 , and DDR ₁ were measured in the same manner as in Example 1.

The compounds [E] and [G] had poor solubility, and some crystals were precipitated during the preparation of the photoreceptor.

Comparative Examples 5 to 7 In the same manner as in Example 18, the same configuration was used, except that the following distyryl compounds [I], [J], [K] were used instead of the distyryl compound [41] used in Example 18. A photoconductor was prepared in the same manner as in Example 18 except for using each.

With respect to the photoreceptor thus obtained, V ₀ , E _1/2 , and DDR ₁ were measured in the same manner as in Example 15.

The compounds [I] and [K] partially crystallized during production of the photoreceptor due to poor solubility.

V _{0 of} the photoreceptors obtained in Examples 1 to 21 and Comparative Examples 1 to 7,
E _1/2, are summarized in Table 1. The measurement results of the DDR _1.

As can be seen from Table 1, the photoreceptor of the present invention has a sufficient charge retention ability even in a laminated type or a single-layer type, has a small dark decay rate to such an extent that it can be sufficiently used as a photoreceptor, and has excellent sensitivity. Is clear from the data.

Further, a repetitive real-photographing test was performed on a photoconductor of Example 18 at the time of positive charging using a commercially available electrophotographic copying machine (EP-350Z; manufactured by Minolta Camera Co., Ltd.). It can be seen that the image has excellent gradation, no change in sensitivity, a clear image is obtained, and the photoreceptor of the present invention has stable repetition characteristics.

Effects of the Invention The present invention has provided a photoconductive compound useful for a photoreceptor.

The photoconductive compound of the present invention is a styryl compound, and is particularly useful as a charge transport material.

The photoreceptor having the styryl compound of the present invention is excellent in photoreceptor characteristics such as sensitivity, charge transport property, initial surface potential, and dark decay rate, and has less light fatigue when repeatedly used.

[Brief description of the drawings]

1 to 5 are schematic views of a photoreceptor according to the present invention. FIGS. 1, 4 and 5 show a dispersion type photoreceptor having a photosensitive layer laminated on a conductive support. 2 and 3 show the structure of a function-separated type photoconductor in which a charge generation layer and a charge transport layer are laminated on a conductive support. DESCRIPTION OF SYMBOLS 1 ... Conductive support, 2 ... Charge transport material 3 ... Photoconductive material, 4 ... Photosensitive layer 5 ... Charge transport layer, 6 ... Photoconductive layer 7 ... Surface protective layer, 8 ... Intermediate layer

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 5/06 313 G03G 5/06 316

Claims (1)

(57) [Claims] 1. A photoreceptor having a photosensitive layer containing a distyryl compound represented by the following general formula [I] on a conductive support: [Wherein, Ar ₁ and Ar _{2 each} independently may have a substituent,
Ar ₃ represents an alkyl group, an aralkyl group or an aryl group, each of which may have a substituent; R ₁ and R _{2 each} independently represent hydrogen, an alkyl group, an alkoxy group or a halogen; R ₃ represents hydrogen, an alkyl group, a thienyl group, a furyl group, a pyrrole group, a pyridyl group, an aralkyl group, an alkenyl group or an alkynyl group. ]