JPH0950142A - Photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photoreceptor excellent in initial surface potential characteristics and not causing the rise of residual potential or generating image noise such as black spots and white spots by successively laminating a specified dispersion layer and a specified photosensitive layer on a substrate. SOLUTION: An electrically conductive layer 2 and an undercoat layer 3 are formed as a dispersion layer on a substrate 1 and an electric charge generating layer 4 and an electric charge transferring layer 5 are successively laminated as a photosensitive layer on the undercoat layer 3. The dispersion layer contains electrically conductive fine powder of tantalum-doped tin oxide dispersed in a resin. The tantalum-doped tin oxide is obtd. by doping tin oxide with 0.1-10wt.% metal tantalum. The average particle diameter of the fine powder is <=2μm. Function as the undercoat layer 3 is imparted by incorporating the fine powder by about <=40wt.% of the total amt. of the dispersion layer and function as the electrically conductive layer 2 is imparted by incorporating the fine powder by >=30wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member, and more particularly to a photosensitive member comprising a support and a dispersion layer and a photosensitive layer sequentially laminated thereon.

[0002]

2. Description of the Related Art An electrophotographic photosensitive member generally comprises a photosensitive layer formed on a conductive support such as aluminum. However, when the photosensitive layer is directly formed on the conductive support to form the photosensitive body, unnecessary charges are likely to be injected from the support, so that noise is likely to occur in the formed image. It is considered that this is because the conductive support such as aluminum generally has irregularities on the surface, so that electric charges are likely to be concentrated on the convex portions on the surface and breakdown occurs at that portion. Therefore, for example, in the case of regular development, the electrostatic latent image necessary for image formation on the photoconductor is canceled by unnecessary injection of electric charges from the support, so that a toner image is originally formed on the canceled part. A toner image is not formed even though it is an appropriate portion, and so-called white spots cause image noise. In the case of reversal development, on the contrary, a toner image is formed in a place where a toner image should not be formed, which causes image noise called so-called black spot.

In order to prevent unnecessary injection of charges from the conductive support to the photosensitive layer as described above, there is known a technique of forming an intermediate layer between the conductive support and the photosensitive layer.

However, when the intermediate layer is an insulating layer composed of a resin having a high electric resistance alone, the flow of charges from the support to the photosensitive layer is not smooth, and the surface potential of the photosensitive member reaches a predetermined value after exposure. Another problem arises in that the residual potential does not decrease but increases.

Therefore, in order to solve such a problem, the electric resistance can be lowered by making the film thickness of the insulating layer very thin. However, if the film thickness is made thin, defects and irregularities on the surface of the support will occur. Can not be covered enough,
The function as the intermediate layer is not fully fulfilled. Also,
Techniques for incorporating various conductive additives in the insulating layer have also been proposed. For example, JP-A-60-144755 discloses a resin dispersion layer in which antimony-doped tin oxide is dispersed as a conductive fine particle in a resin.

Further, in recent years, with the diversification of electrophotographic apparatuses, it has been desired to provide a photoconductor for backside exposure, a belt-shaped photoconductor or the like, and a non-conductive support such as a resin film or glass. A technique in which a conductive intermediate layer is formed on the conductive intermediate layer and is used as a conductive support of a photoconductor is also under study.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and as a layer formed between a support of a photosensitive member and a photosensitive layer, tantalum which is pollution-free and excellent in safety. It is an object to provide a novel layer containing doped tin oxide conductive fine particles.

Further, the present invention provides excellent initial surface potential characteristics by providing the above-mentioned novel layer between the photosensitive layer and the photosensitive layer.
An object of the present invention is to provide a photoconductor that does not cause an image noise such as an increase in residual potential and black spots and white spots.

Furthermore, the present invention imparts conductivity, which can be used as a support for a photoreceptor, by forming the above-mentioned novel layer on a non-conductive support, thereby providing a safe and electrostatic property. The object is to provide a stable photoconductor.

[0010]

That is, the present invention relates to a photoreceptor comprising a support and a dispersion layer and a photosensitive layer in which tantalum-doped tin oxide fine powder is dispersed in a resin in this order.

The dispersion layer is a novel dispersion layer obtained by dispersing tantalum-doped tin oxide fine powder in a binder resin solution.

According to the present invention, by providing the above-mentioned dispersion layer, it is possible to provide a photoconductor which is less likely to cause image noise, has no pollution and is excellent in safety while ensuring a desired charging ability. .

That is, in the present invention, by incorporating the tantalum-doped tin oxide fine powder having conductivity into the dispersion layer, the volume resistance value of the dispersion layer can be lowered as compared with the case where the resin layer is constituted alone. This makes it possible to increase the thickness of the dispersion layer without increasing the residual potential. Then, even if there are irregularities on the surface of the support or there are defects on the surface of the support, such as when the surface is not cut, the presence of the dispersion layer covers the surface irregularities and defects to finish the support smoothly. As a result, it is possible to suppress the generation of image noise such as black spots and white spots due to the injection of unnecessary charges from the uneven portions and the defective portions of the support into the photosensitive layer.

The tantalum-doped tin oxide (SnO ₂ ) used in the present invention contains tin oxide containing 0.1% tantalum metal.
10 to 10% by weight is doped. Doping can be performed by solid solution of tin oxide and tantalum or by coating tantalum on the surface of tin oxide. Further, the doping may be performed by fusing tantalum to tin oxide.

The tantalum-doped tin oxide has an average particle size of 2 μm.
Below, those having a thickness of preferably 0.01 to 1.2 μm, more preferably 0.3 to 1.0 μm are used. If the particle size is too large, not only the dispersibility in the layer deteriorates, but also the dispersion layer cannot be formed smoothly.

The dispersion layer contains tantalum-doped tin oxide in an amount of 5 to 70% by weight based on the total weight of the dispersion layer. If the amount is too small, the volume resistance of the dispersion layer does not sufficiently decrease, which may lead to an increase in residual potential and a decrease in sensitivity. On the other hand, if the amount added is too large, the dispersion layer is not uniformly formed, which causes image defects. In addition, the adhesion is poor, and the film is brittle and lacks strength.
A desired transmissivity cannot be obtained in a photoreceptor for backside exposure.

In the present invention, a photoreceptor is constructed by laminating a photosensitive layer and a dispersion layer in which tantalum-doped tin oxide fine powder is dispersed in a resin on a support. The physical properties of the dispersion layer, particularly the volume resistance value, will be different.

The dispersion layer is classified into an undercoat layer and a conductive layer according to its volume resistance value. Volume resistance value is 1 × 10 ⁶ to 1 × 1
0 ¹⁴ Ω · cm, preferably 1 × 10 ⁸ to 1 × 10 ¹² Ω · c
m is the undercoat layer, and the volume resistance is 1 × 10 ⁶ Ω · cm
The following is used as a conductive layer. The volume resistance value of the dispersion layer depends on the type of binder resin that constitutes the dispersion layer, the particle size of the tin oxide fine powder, the amount of tantalum dope to the tin oxide fine powder, or the content of the tantalum-doped tin oxide fine powder. . Therefore, the volume resistance value cannot be unconditionally specified only by the content of the tantalum-doped tin oxide fine powder, but in the range of the content in the dispersion layer described above, the tantalum-doped tin oxide fine powder is dispersed in the entire dispersion layer. By containing approximately 40% by weight or less, the function as an undercoat layer can be provided, and by containing 30% by weight or more, the function as a conductive layer can be provided.

Further, in the present invention, the dispersibility of the coating liquid is further improved by using tin oxide doped with tantalum and then surface-treated with a coupling agent such as a silane coupling agent or a titanium coupling agent. Thus, the coating film can be formed uniformly. Moreover, the moisture resistance can be further improved by the coupling treatment.

Examples of the form of the photoreceptor of the present invention include those shown in FIGS.

For example, a photoconductor in which a subbing layer 3 is formed on a support 1 as shown in FIG. 1, and a charge generation layer 4 and a charge transport layer 5 are laminated in this order as a photoconductive layer on the subbing layer 3. A conductive layer 2 is formed as a dispersion layer on a support as shown in FIG. 2, and a charge transport layer 4 and a charge generation layer 5 are formed thereon as photosensitive layers.
A conductive layer 2 and a subbing layer 3 are formed as a disperse layer on a photosensitive member formed by sequentially stacking and a support 1 as shown in FIG. It is a photoreceptor in which a transport layer 5 is sequentially laminated. In the structure shown in FIG. 3, at least one of the conductive layer and the undercoat layer may be the dispersion layer of the present invention.

The photoconductor of the present invention can take various forms as described above, and as will be described later, the support is not limited to being conductive, and a non-conductive one can also be used.

In the structure in which the dispersion layer is used as the undercoat layer (eg, FIG. 1), the volume resistance value of the undercoat layer can be made lower than that in the case where the resin alone is used, and the residual potential The rise can be suppressed. Even if there are irregularities or surface defects on the surface of the support such as a non-cutting tube, by making the thickness of the dispersion layer thick, the surface irregularities and slight defects can be covered to smooth the support. Since it can be finished, it is possible to prevent unnecessary electric charges from being injected into the photosensitive layer from uneven portions or defective portions of the support, and to suppress the generation of image noise. Furthermore, when a conductive support containing different metals (for example, an aluminum alloy) is used as the support, charge injection from the different metal portion into the photosensitive layer is likely to occur, but this injection is caused by the presence of the undercoat layer. Can be prevented.

In the structures shown in FIGS. 2 and 3, either a conductive or non-conductive support can be used as the support. In this configuration, the resistance value of the support itself can be controlled to a desired value by adjusting the conductive layer to an appropriate volume resistance value, and the electrostatic characteristics can be stabilized. In addition, since the support is coated with a conductive layer, it is possible to use a support having irregularities or slight defects on the surface thereof, or a conductive support containing a dissimilar metal, like the undercoat layer. .

Further, in the structure shown in FIGS. 2 and 3, the above-mentioned dispersion layer is provided as a conductive layer on a non-conductive support such as glass to impart conductivity to the support, thereby making it possible to perform back exposure. It is possible to provide a usable photoconductor.

As the support, copper, aluminum, iron,
A conductive foil or plate made of nickel or the like in the form of a sheet or a drum is used. Further, the above metal was vacuum-deposited or electroless-plated on a resin film or the like, or a layer of a conductive compound such as a conductive polymer, indium oxide or tin oxide was similarly provided on the paper or the resin film by coating or vapor deposition. The thing etc. are used. The support of the present invention may be provided with conductivity by forming the above-described conductive layer of the present invention on the surface of a non-conductive material such as an insulating resin film or paper.

Of these, cylindrical aluminum or aluminum alloy is generally used as the support. Specifically, the aluminum pipe that has been extruded and then drawn is cut, and the outer surface is cut by a cutting tool such as a diamond tool to a depth of approximately 0.2 to 0.3 mm (cutting pipe). After deep drawing an aluminum disc into a cup shape, the outer surface is finished by ironing (DI pipe), after impact machining an aluminum disc into a cup shape, the outer surface is ironed A finished product (EI pipe), an extruded product, and a cold drawn product (ED pipe) can be used. Further, those obtained by further cutting these surfaces may be used.

In the present invention, the surface is not cut because it has a predetermined undercoat layer or conductive layer between the support and the photosensitive layer as described above. However, it can be sufficiently used as a support for a photoreceptor.

The film thickness of the dispersion layer differs depending on whether it is formed on a conductive support or a high resistance support.
Further, in the case of only the undercoat layer or the conductive layer, it is different in the case of using the undercoat layer and the conductive layer together, but if the thickness is too thin, the desired effect as the dispersion layer cannot be obtained, and if it is too thick, the dispersion layer Since the electric resistance increases and the residual potential increases with repeated use, it is generally 0.1 to 30 μm, preferably 1 to 30 μm, and more preferably 1 to 20 μm. Within the above range, the film thickness is appropriately selected according to each configuration.

A case where a photoconductor as shown in FIG. 1 is manufactured as the photoconductor of the present invention will be described. In this case, tantalum-doped tin oxide fine powder is dispersed in a binder resin solution described below, and this solution is applied onto a conductive support and dried to form a dispersion layer. After coating, it is preferable to perform drying in the range of 60 to 120 ° C. As the resin constituting the dispersion layer, any resin may be used as long as it has strong adhesion to a support, sufficient solvent resistance, good dispersibility of fine powder, and the like. Conventionally known polyvinyl alcohol, polyvinyl methyl ether, poly-N-vinyl imidazole, ethyl cellulose, methyl cellulose, ethylene-acrylic acid copolymer, casein, gelatin, polyamide and the like can be used. Further, thermoplastic resins such as general polyester resin, acrylic resin, vinyl acetate resin, vinyl chloride-vinyl acetate resin, polyvinyl butyral resin, alkyd resin, melamine resin, urethane resin, epoxy resin, silicone resin, phenol resin, etc. A thermosetting resin or the like can be used. Incidentally, among these,
Polyester resin, acrylic-melamine resin, urethane resin and the like are preferable from the viewpoint of adhesiveness and coatability.

In the dispersion layer, zinc oxide, calcium oxide, barium oxide, titanium oxide, silicon oxide, if necessary,
Barium sulfate fine powder, calcium sulfate, barium carbonate,
A non-conductive white powder such as magnesium carbonate may be added. By adding the non-conductive white powder, the reflectance of light in the dispersion layer can be increased and the sensitivity of the photoconductor can be improved.

As the method for applying the dispersion layer on the support, dip coating method, spray coating method, spinner coating method, wire bar coating method, blade coating method, roller coating method,
It can be performed using a coating method such as a curtain coating method.

On the dispersion layer formed as described above, the charge generating material is vacuum-deposited, or is dissolved in a solvent such as amine and applied, or the pigment is bound to an appropriate solvent or, if necessary, bound. A charge generation layer is formed by coating and drying a coating solution prepared by dispersing a resin in a solution.
Furthermore, a solution containing a charge transport material and a binder resin is applied and dried on this to form a charge transport layer.

As described above, the photoreceptor of the present invention having the structure shown in FIG. 1 is manufactured.

In the above description, the photoconductor in which the charge generation layer and the charge transport layer are sequentially laminated as the photoconductive layer on the dispersion layer has been specifically described. In the present invention, the photoconductive layer is the charge transport layer. A structure in which a charge generation layer and a charge generation layer are sequentially stacked may be used. Furthermore, organic photoconductive materials such as polyvinylcarbazole, anthracene, and phthalocyanine can be used as they are,
Alternatively, it may have a single-layer structure formed by mixing and coating with an insulating binder resin.

Further, the photoreceptor of the present invention may have a surface protective layer provided on the photosensitive layer. 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. Further, an organic plasma polymerized film can be used as the surface protective layer. The organic plasma polymerized film may optionally contain oxygen, nitrogen, halogen, and atoms of groups 3 and 5 of the periodic table.

Examples of the charge generating material used in the photoreceptor of the present invention include bisazo pigments, triarylmethane dyes, thiazine dyes, oxazine dyes, xanthene dyes, cyanine dyes, styryl dyes, pyrylium dyes. Examples include organic substances such as azo dyes, quinacdrine dyes, indigo pigments, perylene pigments, polycyclic quinone pigments, bisbenzimidazole pigments, indathlon pigments, squarylium pigments, and phthalocyanine pigments. In addition, any material that absorbs light and generates charge carriers with extremely high efficiency can be used.

Further, as the charge transporting material used in the above-mentioned photoreceptor, hydrazone compounds, pyrazoline compounds, styryl compounds, triphenylmethane compounds, oxadiazole compounds, carbazole compounds, stilbene compounds, enamine compounds, oxazole compounds. Various compounds such as a triphenylamine compound, a tetraphenylbenzidine compound, and an azine compound can be used.

The binder resin used in the production of the above-mentioned photoreceptor is electrically insulating, and is measured by itself to be 1 × 10 ¹²
It is desirable to have a volume resistance of Ω · cm or more. For example, a binder such as a thermoplastic resin, a thermosetting resin, a photocurable resin, or a photoconductive resin known per se can be used. Specifically, saturated polyester resin, polyamide resin, acrylic resin, ethylene-vinyl acetate resin, ion-crosslinked olefin copolymer (ionomer), styrene-
Thermoplastic resin such as butadiene block copolymer, polycarbonate, vinyl chloride-vinyl acetate copolymer, cellulose ester, polyimide, styrene resin; epoxy resin, urethane resin, silicone resin, phenol resin,
Thermosetting resins such as melamine resins, xylene resins, alkyd resins, and thermosetting acrylic resins; photocurable resins; photoconductive resins such as polyvinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylpyrrole, etc., and binders thereof. The resins are used alone or in combination of two or more. When the charge transport material is a polymer charge transport material that can be used as a binder itself, other binder resin may not be used.

The photoreceptor of the present invention comprises a binder resin, a plasticizer such as halogenated paraffin, polyvinyl chloride, dimethylnaphthalene, dibutyl phthalate, O-terphenyl, chloranil, tetracyanoethylene, 2, and the like.
Electron-withdrawing sensitizers such as 4,7-trinitrofluorenone, 5,6-dicyanobenzoquinone, tetracyanoquinodimethane, tetrachlorophthalic anhydride and 3.5-dinitrobenzoic acid, methyl violet, rhodamine B, cyanine dye A sensitizer such as a pyrylium salt or a thiapyrylium salt may be used.

The present invention will be described in detail below with reference to specific examples.

[0042]

【Example】

Example 1 10 parts by weight of a thermosetting acrylic resin (Acridic A405, manufactured by Dainippon Ink and Chemicals), 10 parts by weight of fine powder of tantalum-doped tin oxide (SnO ₂ ) (Pastran TYPE-VI, manufactured by Mitsui Mining & Smelting Co., Ltd.) 2 parts by weight of melamine resin (Super Beckamine J820, manufactured by Dainippon Ink and Chemicals, Inc.) were dispersed in 100 parts by weight of toluene.

The obtained dispersion liquid was applied onto an aluminum drum having an outer diameter of 30 mm (surface roughness Rt = 3 μm) by ring coating, and 15
It was dried at 0 ° C. for 30 minutes to form a conductive layer (volume resistance: 8.2 × 10 ⁴ Ω · cm) having a film thickness of 15 μm. The surface roughness Rt of the obtained conductive layer was 0.1 μm.

A solution prepared by dissolving 5 parts by weight of N-alkoxymethylated nylon resin in a mixed solvent consisting of 5 parts by weight of methanol and 50 parts by weight of n-butanol was coated on the conductive layer to give a film thickness of 1.0 μm. Undercoat layer (7.8 × 10 ⁹ Ω ・
cm) formed.

Next, 1 part by weight of τ type metal-free phthalocyanine and 1.0 part by weight of polyvinyl butyral were dispersed together with 100 parts by weight of tetrahydrofuran (THF) by a sand mill. The obtained phthalocyanine-based dispersion liquid,
A charge generation layer was formed by coating the undercoat layer so that the film thickness after drying was 0.2 μm.

The following chemical formula:

Embedded image 10 parts by weight of a butadiene compound represented by the formula, polycarbonate resin (Panlite K-1300, manufactured by Teijin Chemicals Ltd.) 1
A coating liquid consisting of 0 parts by weight and 180 parts by weight of dichloromethane was applied onto the charge generation layer and dried to form a charge transport layer having a film thickness of 25 μm. A laminated type photoreceptor was produced as described above.

Example 2 Tantalum-doped tin oxide (Pastran TYPE-V
I, manufactured by Mitsui Mining & Smelting Co., Ltd.) 100 parts by weight of fine powder, polyurethane (Desmodur 800, manufactured by Nippon Polyurethane Co., Ltd.)
80 parts by weight, 80 parts by weight of toluene, 80 parts by weight of xylene, 65 parts by weight of ethyl acetate were dispersed in a paint shaker for 3 hours, and further isocyanate (Sumijour N7
(5, Sumitomo Chemical Co., Ltd.) 10 parts by weight was added to obtain a coating liquid. This coating solution is applied on a glass cylinder and dried by heating at 120 ° C. for 10 minutes to give a film thickness of 2 μm and a volume resistance of 7 × 10 ⁴ Ω · c.
m, and a light transmittance of 86% was formed as a conductive layer.

A solution prepared by dissolving 5 parts by weight of N-alkoxymethylated nylon resin in a mixed solvent consisting of 5 parts by weight of methanol and 50 parts by weight of n-butanol was coated on the conductive layer to give a film thickness of 1.0 μm. Undercoat layer (7.8 × 10 ⁹ Ω ・
cm) formed.

Next, 1 part by weight of τ-type metal-free phthalocyanine, 1.0 part by weight of polyvinyl butyral, and 100 parts by weight of tetrahydrofuran (THF) were dispersed in a sand mill. The obtained phthalocyanine-based dispersion liquid,
A charge generation layer was formed by coating the undercoat layer so that the film thickness after drying was 0.2 μm.

Then, the following chemical formula:

Embedded image 10 parts by weight of the distyryl compound and 12 parts by weight of a polycarbonate resin (Panlite PC-Z, manufactured by Teijin Kasei) are dispersed in 180 parts by weight of tetrahydrofuran, and the resulting coating solution is applied onto the charge generation layer and dried. Let the film thickness 2
A 5 μm charge transport layer was formed. A laminated type photoreceptor was produced as described above.

Example 3 Tantalum-doped tin oxide (Pastran TYPE-V)
I, manufactured by Mitsui Mining & Smelting Co., Ltd.) 2 parts by weight of fine powder was added to a silane coupling agent C ₅ F ₁₁ CO ₂ (CH ₂ ) ₃ Si (OCH ₃ ) ₃₀ .
The mixture was stirred in a solution consisting of 2 parts by weight and 30 parts by weight of methanol. The contents were taken out and dried at 110 ° C. for 1 hour. The fine powder was subjected to the coupling treatment as described above.

2 parts by weight of tantalum-doped tin oxide subjected to the coupling treatment and a polyamide resin (CM-8000,
12 parts by weight (manufactured by Toray Industries, Inc.) were dispersed in 100 parts by weight of methanol.

The obtained dispersion was applied onto an aluminum drum having an outer diameter of 30 mm (surface roughness Rt = 0.7 μm) by ring coating,
Undercoat layer with a thickness of 1.5 μm after drying at 80 ° C for 30 minutes
(Volume resistance 4 × 10 ¹¹ Ω · cm) was formed.

Next, 1 part by weight of τ-type metal-free phthalocyanine, 1.0 part by weight of polyvinyl butyral, and 100 parts by weight of tetrahydrofuran (THF) were dispersed in a sand mill. The obtained phthalocyanine-based dispersion liquid,
A charge generation layer was formed by coating the undercoat layer so that the film thickness after drying was 0.2 μm.

Then, the following chemical formula:

Embedded image 10 parts by weight of the distyryl compound and 12 parts by weight of a polycarbonate resin (Panlite PC-Z, manufactured by Teijin Kasei) are dispersed in 180 parts by weight of tetrahydrofuran, and the resulting coating solution is applied onto the charge generation layer and dried. Let the film thickness 2
A 5 μm charge transport layer was formed. A laminated type photoreceptor was produced as described above.

Comparative Example 1 A photoconductor was prepared in the same manner as in Example 1 except that the conductive layer and the undercoat layer were not provided.

Comparative Example 2 A photoconductor was prepared in the same manner as in Example 1 except that carbon black was added instead of the tantalum-doped tin oxide used in the conductive layer.

The photoconductors of Examples 1 to 3 and Comparative Examples 1 and 2 obtained as described above were incorporated into a laser printer Sp101 manufactured by Minolta Co., Ltd., and a grid voltage was set to -750.
V, the initial surface potential V _O (V) of each photoconductor,
Exposure amount required for the surface potential to be attenuated to half of the initial surface potential (hereinafter, half exposure amount) E _2/1 (erg / cm ² ), initial potential decay rate DDR ₁ (when left in the dark for 1 second %) Was measured and the results are shown in Table 1.

Next, reversal development was performed, and the occurrence of black spots on the white paper portion and white spots on the solid black portion on the image was observed and evaluated according to the following criteria. The results are shown in Table 1.

◯: Black spots, white spots, or interference fringes were not observed at all or were slightly observed, but there was no problem in practical use ×: Recognized and not practical xx: Many observed and very problematic

[0061]

[Table 1]

[0062]

The photoconductor of the present invention has excellent initial surface potential characteristics, and does not cause an increase in residual potential and image noise such as black spots and white spots.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a photoconductor.

FIG. 2 is a schematic cross-sectional view of a photoconductor.

FIG. 3 is a schematic sectional view of a photoconductor.

[Explanation of reference numerals] 1: support, 2: conductive layer, 3: undercoat layer, 4: charge generation layer, 5: charge transport layer

Claims (1)

[Claims] 1. A photoreceptor comprising a support and a dispersion layer formed by dispersing tantalum-doped tin oxide fine powder in a resin, and a photosensitive layer in this order.