JPH07181703A - Electrophotographic photoreceptor and method for electrophotography - Google Patents

Abstract

PURPOSE:To decrease dark decay and to decrease the rise of residual potential even for repeated use without losing such effects for adhesion property between a conductive supporting body and photosensitive layer and of avoiding defects in a conductive supporting body, by incorporating a high-molecular charge transfer material into a base coating layer as an effective component. CONSTITUTION:This electrophotographic photoreceptor has a base coating layer 13 and a photosensitive layer 15 successively formed on a conductive supporting body 11. The base coating layer 13 contains a high-molecular charge transfer material as an effective component. The base coating layer 13 is formed by applying a high-molecular charge transfer material as an effective component on the conductive supporting body. As for the high-molecular charge transfer material, a polymer having carbazole ring in the main chain or side chain, polymer having a hydrazine structure in the main chain or side chain, polysilylene polymer, a polymer having a tertiary amine structure in the main chain or side chain, or other polymers are used. If necessary, a binder resin which is electrically inactive is used for the base coating layer 13.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electrophotographic photoreceptor having an undercoat layer containing a polymer charge transport material.

[0002]

2. Description of the Related Art An electrophotographic photosensitive member is composed of a conductive support and a photosensitive layer as essential requirements. The adhesion between the conductive support and the photosensitive layer is improved, and the film-forming property and coating property of the photosensitive layer are improved. Between the conductive support and the photosensitive layer, for the purpose of covering defects of the conductive support, protecting the photosensitive layer against electric breakdown, and improving dark decay due to charge injection from the conductive support to the photosensitive layer. An undercoat layer may be provided.

For the undercoat layer, SiO, Al ₂ is formed on the support.
A method of providing an inorganic material such as O by a method such as steam, sputtering, or anodic oxidation is known, and A in the charge generation layer is
It is also known to contain 1 ₂ O ₃ (Japanese Patent Laid-Open No. 55-142354) and also to contain a metal powder in the charge generation layer (Japanese Laid-Open Patent Publication No. 60-214364).

Further, as an undercoat layer, a polyamide resin (JP-A-58-30757 and JP-A-58-98739) and an alcohol-soluble nylon resin (JP-A-60-
196766), water-soluble polyvinyl butyral resin (JP-A-60-232553), and polyvinyl butyral resin (JP-A-58-106549).

On the other hand, Japanese Patent Application Laid-Open No. 61-296362 discloses an undercoat layer made of a charge transport material, a charge generating material and a resin. However, even when these undercoat layers are used, none of them satisfy the above-mentioned characteristics, and further improvement has been desired.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a photosensitive layer which is excellent in the adhesiveness between the conductive support and the photosensitive layer and in which the defects of the conductive support are eliminated. Another object of the present invention is to reduce dark decay even after repeated use,
Another object is to provide a photoconductor in which the increase in residual potential is small. Another object of the present invention is to provide a photoreceptor and an image forming method which do not generate a moire image even when image exposure is performed using coherent light. Still another object of the present invention is to provide a laminated photoreceptor in which high sensitivity is maintained even after repeated use, and the delay of rising of the surface potential during charging and the dark decay are small. Still another object of the present invention is to provide a laminated photoreceptor which maintains high sensitivity even after repeated use and has a small increase in residual potential.

[0007]

When an undercoat layer is provided between a conductive substrate and a photosensitive layer, a residual potential is generated especially when the undercoat layer is an insulating substance such as resin or metal oxide. Cheap. On the other hand, when a conductive material is used for the undercoat layer, dark decay occurs due to charge injection from the substrate into the photosensitive layer. It has been proposed to use a low-molecular-weight charge transport material for the undercoat layer in order to compensate for such a defect in the electrostatic characteristics related to the undercoat layer, but unfortunately, the low-molecular charge transport material is not suitable for the photosensitive layer. When it was applied and formed, it bleeded to the photosensitive layer side, and as a result, a remarkable effect could not be obtained. In order to solve such a problem in electrical characteristics, the present inventors have studied an undercoat layer material and completed the present invention by introducing a polymer charge transport material.

That is, according to the present invention, in an electrophotographic photosensitive member comprising a conductive support and an undercoat layer and a photosensitive layer provided in this order, a polymer charge transporting material is contained as an active ingredient in the undercoat layer. An electrophotographic photoreceptor is provided. Further, according to the present invention, by providing a metal oxide particle in the undercoat layer, a photoreceptor and an image forming method which do not generate a moire image even when image exposure is performed using coherent light are provided. To be done. Further, according to the present invention, when the photosensitive layer has a structure in which the charge generating layer and the charge transporting layer are laminated in this order, a laminated photoreceptor is provided in which the delay of rising of the surface potential during charging and the dark decay are small. Further, according to the present invention, when the photosensitive layer has a structure in which the charge transport layer and the charge generating layer are laminated in this order, a laminated photoreceptor in which the increase in residual potential is small is provided.

The present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing a structural example of the electrophotographic photosensitive member of the present invention, which has a structure in which an undercoat layer 13 and then a photosensitive layer 15 are provided on a conductive substrate 11. FIG. 2 is a sectional view showing another structural example of the present invention. The photosensitive layer is the charge generation layer 1.
The 7-charge transport layer 19 is laminated in this order. In Figure 3,
It is sectional drawing which shows another structural example. The photosensitive layers are laminated in the order of the charge transport layer 19 and the charge generation layer 17. 4, 5, and 6 are cross-sectional views showing yet another configuration example. A protective layer 21 is provided on each of the configurations shown in FIGS. 1, 2 and 3. 11 Conductive Substrate 13 Undercoat Layer 15 Photosensitive Layer 17 Charge Generation Layer 19 Charge Transport Layer 21 Protective Layer

The conductive substrate has a volume resistance of 10 ¹⁵ Ωc.
Those exhibiting conductivity of m or less, for example, metal such as aluminum, nickel chrome, nichrome, copper, silver, gold, platinum, etc., metal oxides such as tin oxide, indium oxide, etc. by vapor deposition or sputtering to form a film or cylinder. -Shaped plastic, paper, etc., or aluminum, aluminum alloy, nickel, stainless steel, etc. plates and D. D. , I. I. It is possible to use a tube or the like which is made into a raw tube by a method such as extrusion or drawing and then surface-treated by cutting, superfinishing, polishing or the like.

Next, the undercoat layer 13 will be described. The undercoat layer 13 is provided on the conductive support 11 with a polymer charge transport material as an active ingredient. Examples of the polymer charge transport material include the following. (A) Polymer having carbazole ring in main chain or side chain For example, compounds described in JP-A-50-82056, compounds described in JP-A-54-9632, and JP-A-54-11737. The compounds described in the publication, JP-A-4-
Examples thereof include the compounds described in Japanese Patent No. 183719. (B) Polymer having hydrazone structure in main chain or side chain For example, compounds described in JP-A-57-78402 and compounds disclosed in JP-A-3-50555 are exemplified. (C) Polysilylene Polymer For example, the compounds described in JP-A-63-285552, the compounds described in JP-A-5-19497, and the compounds described in JP-A-5-70595 are exemplified. (D) Polymer having tertiary amine structure in main chain or side chain For example, poly-p-vinyltriphenylamine, compounds described in JP-A-1-13061, JP-A-1-19
No. 049, the compound described in JP-A No. 1-1728, the compound described in JP-A No. 1-105260, the compound described in JP-A No. 2-167335, the compound described in JP-A No. 5-66598. Examples thereof include the compounds described in the publication and the compounds described in JP-A-5-40350. (E) Other Polymers For example, a formaldehyde condensation polymer of nitropyrene, compounds described in JP-A-51-73888, JP-A-5-
Examples thereof include the compounds described in JP-A-6-150749.

The polymer having an electron-donating group used in the present invention is not limited to the above-mentioned polymers, but also copolymers of known monomers, block polymers, graft polymers, star polymers, and For example, it is possible to use a cross-linked polymer having an electron donating group as disclosed in JP-A-3-109406. As the polymer having an electron-donating group used in the present invention, use of a polymer belonging to (b), (c) and (d) among the above-mentioned material groups can give a preferable effect. The polymer having an electron donating group used in the present invention does not necessarily have a high molecular weight and may be a so-called oligomer. Therefore, the weight average molecular weight of the polymer is preferably 1,000 or more, more preferably 2,000 to 2,000,000.
Is.

If desired, an electrically inactive binder resin may be used in combination with the undercoat layer 13 of the present invention. As the binder resin, polyvinyl alcohol, casein, copolymerized nylon, methoxymethylated nylon, polyurethane, polyester, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polyacrylamide , Melamine resin, phenol resin, alkyd-melamine resin, epoxy resin and the like are used.

The undercoat layer 13 of the present invention includes metal oxides such as aluminum oxide, tin oxide, indium oxide, titanium oxide, zirconium oxide, zinc oxide, silicon oxide, tantalum oxide, molybdenum oxide, and tungsten oxide. Also, a mixture thereof, a mixed crystal thereof, or the like can be used in a fine powder state.

For the undercoat layer 13, a polymer charge transporting material may be used as an active ingredient, and if necessary, an electrically inactive binder resin or a metal oxide may be used in combination. It can be formed by dispersing an appropriate solvent such as dioxane, 2-butanone, dichloroethane or the like by a ball mill, an attritor, a sand mill or the like, and diluting the dispersion liquid appropriately and coating. The coating can be performed by using a dip coating method, a spray coating method, a bead coating method, or the like.

The film thickness of the undercoat layer 13 used in the present invention is 0.1 to 10 μm, preferably 0.2 to 5 μm.

The photosensitive layer in the present invention may be either a single layer type or a laminated type, but here, for convenience of description, the laminated type will be described first.

The charge generating layer 17 is a layer containing a charge generating substance as a main component, and a binder resin may be used if necessary. An inorganic material and an organic material can be used as the charge generating substance. Inorganic materials include crystalline selenium,
Examples thereof include amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compounds, and amorphous silicon. As amorphous silicon, dangling bonds terminated with hydrogen atoms or halogen atoms, or those doped with boron atoms, phosphorus atoms, etc. are preferably used.

On the other hand, the organic materials include phthalocyanine pigments, naphthalocyanine pigments, perylene pigments, perinone pigments, quinacridone pigments, quinone condensed polycyclic compounds, squaric acid dyes, azurenium salt dyes,
A monoazo pigment, a disazo pigment, a trisazo pigment, etc. are mentioned and used. These charge generating substances may be used alone or in combination of two or more.

As the binder resin, polyamide, polyurethane, polyester, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polyacrylamide and the like are used.

The binder resin is preferably used in an amount of 0 to 100 parts by weight based on 100 parts by weight of the charge generating substance,
It is preferably 0 to 50 parts by weight. The charge generation layer is a ball mill using a solvent such as tetrahydrofuran, cyclohexane, dichlorohexane, dioxane, or dichloroethane together with a binder resin, if necessary, as the charge generation substance.
It can be formed by dispersing with an attritor, a sand mill, etc., and diluting the dispersion liquid appropriately and applying. The coating can be performed by using a dip coating method, a spray coating method, or a bead coating method. The thickness of the charge generation layer is 0.0
About 1 to 5 μm is suitable, and preferably 0.1 to 2 μm.
m. The charge transport layer 22 can be formed by dissolving or dispersing a charge transport substance and a binder resin in an appropriate solvent, applying the solution on the charge generating layer, and drying. If necessary, a plasticizer, a leveling agent, etc. may be added. The charge transport layer 19 is composed of a charge transport material and a binder or a polymer charge transport material. The charge transport material includes a hole transport material and a charge transport material.

Examples of the charge transport material include chloranil, bromanil, tetracyanoethylene, tetracyanoquinone dimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone. , 2,4,5,7-tetranitroxanthone,
2,4,8-trinitrothioxanthone, 2,6,8-
Examples thereof include electron-accepting substances such as trinitro-4H-indeno [1,2-b] thiophen-4-one and 1,3,7-trinitrodibenzothiophene-5,5-dioxide.

As the hole-transporting substance, poly-N-vinylcarbazole and its derivative, poly-γ-carbazolylethylglutamate and its derivative, pyrene-formaldehyde condensate and its derivative, polyvinylpyrene, polyvinylphenanthrene, oxazole derivative. ,
Oxadiazole derivative, imidazole derivative, monoarylamine derivative, diarylamine derivative, triarylamine derivative, stilbene derivative, α-phenylstilbene derivative, benzidine derivative, diarylmethane derivative, triarylmethane derivative, 9-styrylanthracene derivative, pyrazoline Other known materials such as derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives and butadiene derivatives can be used.

These charge transport materials may be used alone or in admixture of two or more. As the binder resin, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinyl chloride Vinylidene, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol Thermoplastic or thermosetting resins such as resins and alkyd resins may be mentioned.

As the solvent, tetrahydrofuran, dioxane, toluene, monochlorobenzene, dichloroethane, methylene chloride, etc. are used. A suitable thickness of the charge transport layer 19 is about 5 to 50 μm.

In the present invention, a plasticizer or a leveling agent may be added to the charge transport layer 19. As the plasticizer, those used as a plasticizer for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount of the plasticizer used is preferably about 0 to 30% by weight based on the binder resin. As the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain are used, and the amount thereof is 0 to 1 weight with respect to the binder resin. % Is appropriate.

Next, the case where the photosensitive layer 15 has a single layer structure will be described. Also in this case, most of them are of the function-separated type, which is composed of a charge-generating substance and a charge-transporting substance. That is, the compounds shown above can be used as the charge generating substance and the charge transporting substance. The single-layer photosensitive layer can be formed by dissolving or dispersing the charge-generating substance, the charge-transporting substance and the binder resin in a suitable solvent, coating and drying the solution. Further, if necessary, a plasticizer, a leveling agent, etc. can be added. As the binder resin, the binder resin mentioned above in the charge transport layer may be used as it is, or the binder resin mentioned in the charge generation layer may be mixed and used. A photoconductor obtained by adding a hole-transporting substance to a eutectic complex formed of a pyrylium-based dye or bisphenol A-based polycarbonate can also be used as a single-layer / single-layer photoconductor. The thickness of the single-layer photosensitive layer 15 is preferably 5 to 100 μm.

Photosensitive materials that can be used in the present invention include:
The protective layer 21 may be provided on the photosensitive layer 15 for the purpose of protecting the photosensitive layer. The material used for this is A
BS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polybutylene, polybutylene terephthalate, polycarbonate, polyether sulfone, polyethylene,
Examples thereof include resins such as polyethylene terephthalate, polyimide, acrylic resin, polymethylpentene, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, polyvinylidene chloride and epoxy resin. The protective layer may also be a fluororesin such as polytetrafluoroethylene, a silicone resin, or a dispersion of an inorganic material such as titanium oxide, oxide, or potassium titanate in these resins for the purpose of improving wear resistance. It can be added.

As a method of forming the protective layer, a usual coating method is adopted. The thickness of the protective layer is preferably about 0.5 to 10 μm. In addition to the above, known materials such as i-C and a-SiC formed by the vacuum thin film forming method can also be used as the protective layer. In the present invention, another intermediate layer (not shown) may be provided between the photosensitive layer and the protective layer. A binder resin is generally used as a main component in the intermediate layer. Examples of these resins include polyamide, alcohol-soluble nylon resin, water-soluble polyvinyl butyral resin, polyvinyl butyral, and polyvinyl alcohol. As a method of forming the intermediate layer, the usual coating method is adopted as described above. The thickness of the intermediate layer is 0.0
About 5 to 2 μm is suitable.

FIG. 7 is a schematic view for explaining the electrophotographic apparatus and electrophotographic process of the present invention, and the following modified examples also belong to the scope of the present invention.

In FIG. 7, the photosensitive member 1 is formed by providing an inorganic photosensitive layer or an organic photosensitive layer on a conductive support. Although the photosensitive member 1 has a drum shape, it may have a sheet shape or an endless belt shape. Charger 3, pre-transfer charger 7, transfer charger 1
0, separation charger 11, pre-cleaning charger 1
A known means such as a corotron, a scorotron, or a charging roller is used for the unit 3. In addition, the image exposure unit 5,
As the light source of the static elimination lamp 2 or the like, general light emitting materials such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL) can be used. Further, various filters such as a sharp cut filter, a bandpass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range. Such a light source,
A transfer process using light irradiation in addition to the process shown in FIG.
By providing a process such as a charge removing process, a cleaning process, or a pre-exposure process, the photoconductor is irradiated with light.

Here, in image exposure, the light is LD, L
When the light is reflected at the lower end of the photosensitive layer, which is coherent such as ED, a moire image is generated in the halftone portion. However, by adding the metal oxide fine powder to the undercoat layer according to the present invention, it is possible to eliminate the moire image by irregularly reflecting or refracting the coherent light.

[0033]

EXAMPLES Next, examples are shown, but the present invention is not limited by the examples. All parts in the examples are parts by weight.

Example 1 On a polyethylene terephthalate film having an aluminum conductive layer, an undercoat layer coating solution and a eutectic complex photoconductive layer coating solution having the following compositions were sequentially applied and dried to a thickness of 1 μm.
An undercoat layer and a eutectic complex photoconductive layer having a thickness of 18 μm were formed. [Undercoat layer coating liquid] 10 parts of a polymer charge transport material having the following structural formula

[Chemical 1] 2-Butanone 50 parts [Eutectoid complex photoconductive layer coating liquid] 4- (4-Dimethylaminophenyl) -2,6-diphenyl thiapyrylium hexafluorophosphate 1.5 parts Polycarbonate (GE-L-141) ) 24 parts Hole transporting compound of the following structural formula 10 parts

[Chemical 2] Methylene chloride 650 parts

Comparative Example 1 A photoconductor of Comparative Example 1 was prepared in the same manner as in Example 1 except that the coating liquid for undercoat layer was changed to the following liquid. [Undercoat layer coating liquid] Water-soluble polyvinyl acetal 15 parts (Sekisui Chemical Co., Ltd .: W-101 10% aqueous solution) Water 20 parts Methanol 50 parts

The photoconductor thus obtained was used as an electrostatic paper analyzer [SP-42.
8 manufactured by Kawaguchi Electric Co., Ltd.] and charged at a corona discharge voltage of −5.5 kV or +6.0 kV, a potential V _m (V) after 20 seconds, a potential V _o (V) after 20 seconds of dark decay, Residual potential V _R (V) after 20 seconds of exposure at an intensity of 6 lux, and the exposure amount E required to further attenuate the potential V _o to ½
_1/2 [lux · sec] was measured. The potential holding ratio is defined as follows.

Further, the charging and the exposure under the above conditions are continuously performed at the same time.
After the photoconductor was fatigued for a long time, the photoconductor characteristics were measured in the same manner as above. The results are shown in Table 1.

[Table 1]

Example 2 An undercoating layer coating solution, a charge generating layer coating solution and a charge transporting layer coating solution having the following compositions were sequentially coated on a nickel endless belt having a thickness of 50 μm prepared by electroforming. -Dried to form an undercoat layer having a thickness of 0.5 µm, a charge generating layer having a thickness of 0.2 µm, and a charge transporting layer having a thickness of 23 µm. [Undercoat layer coating liquid] 10 parts of a polymer charge transport material having the following structural formula

[Chemical 3] Toluene 50 parts [Charge generation layer coating liquid] 5 parts of charge generation substance having the following structural formula

[Chemical 4] Polyvinyl butyral 3 parts (Sekisui Chemical Co., Ltd .: S-REC BL-1) Cyclohexanone 200 parts 4-Methyl-2-pentanone 90 parts [Charge transport layer coating liquid] Polycarbonate 11 parts (Teijin Kasei: Panlite K-1300) 8 parts of charge transport material with the following structural formula

[Chemical 5] Tetrahydrofuran 80 parts

Comparative Example 2 A photoconductor of Comparative Example 2 was prepared in the same manner as in Example 2 except that the undercoat layer was not provided.

Example 3 A photoconductor was manufactured in the same manner as in Example 2 except that the coating liquid for undercoat layer was changed to the following liquid. [Undercoat layer coating liquid] 8 parts of polymer charge transport material having the following structural formula

[Chemical 6] Titanium dioxide powder 15 parts (Ishihara Sangyo Co., Ltd .: Taipaque R-670) Polyvinyl butyral 2 parts (Sekisui Chemical Co., Ltd .: S-REC BL-1) 4-Methyl-2 pentanone 50 parts

Comparative Example 3 A photoconductor of Comparative Example 3 was prepared in the same manner as in Example 3, except that the coating liquid for undercoat layer was changed to the following liquid. [Undercoat layer coating liquid] Alcohol-soluble polyamide 7 parts (Toray: Amilan CM-80000) Titanium dioxide powder 15 parts (Ishihara Sangyo Co., Ltd .: Taipaque R-670) Isopropyl alcohol 20 parts Methanol 50 parts

Example 4 A photoconductor was prepared in the same manner as in Example 3 except that the coating liquid for charge generation layer was changed to the following liquid. [Charge generating layer coating liquid] 5 parts of the charge generating substance having the following structure

[Chemical 7] Polyester 3 parts (Toyobo: Byron 200) Cyclohexanone 200 parts Tetrahydrofuran 90 parts

The photoreceptor obtained as described above was used as an electrostack paper analyzer (SP-428).
Corona discharge voltage-5.
The potential V _m (V) after 20 seconds of charging at 5 KV, the potential V _o (V) after 20 seconds of dark decay, the residual potential V _R (V) after 20 seconds of exposure at an intensity of 6lux, and the potential V _o of 1 The amount of exposure E _1/2 (lux · sec) required to attenuate to _½ was measured. The potential holding ratio is defined as follows.

Further, the charging and the exposure under the above conditions are continuously performed at the same time.
After the photoconductor was fatigued for a long time, the photoconductor characteristics were measured in the same manner as above. The results are shown in Table 2.

[Table 2]

Example 5 An undercoat layer coating solution, a charge transport layer coating solution, and a charge generating layer coating solution having the above composition were sequentially applied and dried on an aluminum cylinder having an outer diameter of 80 mm to give a thickness of 3 μm. Undercoat layer, 23 μm thick charge transport layer, and 0.4 μm thick
The charge generation layer of was formed. [Undercoat layer coating liquid] 10 parts of a polymer charge transport material having the following structural formula

[Chemical 8] Tetrahydrofuran 50 parts [Charge transport layer coating liquid] Polycarbonate 8 parts (Teijin Kasei: Panlite L-1250) 8 parts of charge transport substance having the following structural formula

[Chemical 9] Methylene chloride 80 parts [Charge generation layer coating liquid] 8 parts of the charge transport substance having the following structural formula

[Chemical 10] Polyvinyl butyral 3 parts (Denka Butyral # 5000-A) Tetrahydrofuran 200 parts 4-Methyl-2-pentanone 90 parts

Comparative Example 4 A photoconductor of Comparative Example 4 was prepared in the same manner as in Example 5, except that the coating liquid for undercoat layer was changed to the following liquid. [Undercoat layer coating liquid] Vinyl chloride-vinyl acetate-maleic anhydride copolymer resin 15 parts (Sekisui Chemical Co., Ltd .: S-REC MF-10) Isopropyl alcohol 20 parts Methanol 50 parts

Example 6 An undercoat layer coating solution, a charge transport layer coating solution, a charge generating layer coating solution, and a protective layer coating solution having the following compositions were successively coated and dried on the same cylinder as in Example 5. Then, an undercoat layer having a thickness of 3 μm, a charge transport layer having a thickness of 23 μm, a charge generating layer having a thickness of 0.4 μm, and a protective layer having a thickness of 5 μm were formed. [Undercoat layer coating liquid] 10 parts of a polymer charge transport material having the following structural formula

[Chemical 11] Toluene 50 parts [Charge generation layer coating liquid] Polycarbonate 8 parts (Teijin Kasei: Panlite L-1250) 8 parts of the charge transport substance having the following structural formula

[Chemical 12] Tetrahydrofuran 80 parts [Charge generation layer coating liquid] x-type metal-free phthalocyanine 5 parts Polyvinyl butyral 3 parts (Denka Butyral # 5000-A) Tetrahydrofuran 200 parts 4-Methyl-2-pentanone 90 parts [Protective layer Coating liquid] Tin oxide containing 10% antimony oxide 30 parts Styrene-methacrylic acid-N methylol methacrylamide resin 10 parts Toluene 80 parts n-Butanol 70 parts

Example 7 A photoconductor was prepared in the same manner as in Example 6 except that the coating liquid for undercoat layer was changed to the following liquid. [Undercoat layer coating liquid] 10 parts of a polymer charge transport material having the following structural formula

[Chemical 13] Aluminum oxide powder 30 parts 4-Methyl-2-pentanone 50 parts

Comparative Example 5 A photoconductor of Comparative Example 5 was prepared in the same manner as in Example 7, except that the coating liquid for undercoat layer was changed to the following liquid. [Undercoat layer coating liquid] Alkyd resin 5 parts (Dainippon Chemical Co., Ltd .: Beckzol 1307-60-EL) Melamine resin 5 parts (Dainippon Chemical Co., Ltd .: Super Beckamine G-821-60) Aluminum oxide powder 30 Part 4-methyl-2-pentanone 50 parts

Each of the above-mentioned photoreceptors was used in Japanese Patent Application Laid-Open No. 60-10016.
The following measurement was performed by the evaluation device disclosed in Japanese Patent Laid-Open No. 7. Corona discharge voltage +6.0 kV, potential V _m (V) 20 seconds after charging, potential V _o (V) after dark decay 20 seconds, residual potential V 20 seconds after exposure by white light with intensity 6lux.
_The exposure amount E _1/2 [lux · sec] required to attenuate _R (V) and the potential V _o to 1/2 was measured. The potential holding ratio is defined as follows. Potential holding ratio = V _o / V _m Further, after charging and exposure under the above conditions were continuously performed for 1 hour to expose the photoconductor, the photoconductor characteristics were measured in the same manner as above. The results are shown in Table 3.

[Table 3]

Each of the photoconductors of Examples 2 and 3 was mounted on a laser printer SP2000 manufactured by Ricoh Co., Ltd., and when an image was printed, moire was observed in the image in the case of the photoconductor of Example 2. In the case of the photoconductor of Example 3, moire was not recognized in the image. The photoconductors of Examples 6 and 7 were mounted on a Ricoh copy machine Imagio MF530 having a semiconductor laser as an exposure source, and images were printed. However, the copying machine was modified for a positively charged photoreceptor. As a result, in the case of the photoconductor of Example 6, moire was observed in the image, but in the case of the photoconductor of Example 7, no moire was observed in the image.

[0052]

The photoreceptor of the present invention comprises an undercoat layer containing a polymer charge transport material as an active ingredient on a conductive support,
Since it is sequentially provided on the photosensitive layer and the photosensitive layer, the effect of eliminating the adhesiveness between the conductive support and the photosensitive layer and the defect of the conductive support is not lost, and the dark decay is small even with repeated use, and the residual potential rises. There are few. Further, in such a photoreceptor, when the undercoat layer further contains metal oxide particles, in addition to the above-mentioned effects, a moire image is not generated even when image exposure is performed using coherent light. A photoreceptor is obtained. Moreover, in such a photoreceptor,
When the photosensitive layer has a structure in which the charge generating layer and the charge transporting layer are laminated in this order, a laminated photoreceptor is obtained in which the delay of the rise of the surface potential during charging and the dark decay are extremely small. Further, in such a photoreceptor, when the photosensitive layer has a structure in which a charge transport layer and a charge generating layer are laminated in this order, a laminated photoreceptor in which the increase in residual potential is extremely small can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration example of an electrophotographic photosensitive member of the present invention.

FIG. 2 is a sectional view showing another configuration example of the electrophotographic photosensitive member of the present invention.

FIG. 3 is a cross-sectional view showing another configuration example of the electrophotographic photosensitive member of the present invention.

FIG. 4 is a cross-sectional view showing another configuration example of the electrophotographic photosensitive member of the present invention.

FIG. 5 is a cross-sectional view showing another configuration example of the electrophotographic photosensitive member of the present invention.

FIG. 6 is a sectional view showing another configuration example of the electrophotographic photosensitive member of the present invention.

FIG. 7 is an explanatory diagram of an electrophotographic apparatus having an electrophotographic photosensitive member of the present invention inserted therein.

Claims (5)

[Claims] 1. An electrophotographic photosensitive member comprising a conductive support and an undercoat layer and a photosensitive layer sequentially provided thereon, wherein the undercoat layer contains a polymer charge transport material as an active ingredient. An electrophotographic photosensitive member. 2. The electrophotographic photosensitive member according to claim 1, wherein the undercoat layer further contains metal oxide particles. 3. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer is formed by laminating a charge transport layer and a charge generating layer in this order. 4. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer is formed by laminating a charge generation layer and a charge transport layer in this order. 5. An electrophotographic method using the electrophotographic photosensitive member according to claim 2, wherein a latent image is formed on the electrophotographic photosensitive member using coherent light.