JPH0862865A - Image forming method - Google Patents

Abstract

PURPOSE: To obtain an excellent wear resistance, to prevent deposition of foreign matter or contamination on the surface of a photoreceptor, and to decrease defects in image qualities by using a photoreceptor containing a specified binder resin in the photosensitive layer. CONSTITUTION: The photoreceptor used has a photosensitive layer formed on a conductive supporting body. The photosensitive layer contains a polycarbonate resin as a binder resin selected from among polycarbonate resins comprising repeating structural units expressed by formulae I to III. In an electrifying process of the photoreceptor, a contact electrifying device which impresses voltage on a conductive member in contact with the surface of the photoreceptor is used. In the formulae I and II, each of X, X' is hydrogen atom, a halogen atom or methyl group, R is hydrogen atom, a halogen atom, hydroxyl group, carboxyl group, or the like, and j is an integer 1 to 3. In the formula III, R is hydrogen atom, methyl group or aryl group, each of X1 -X3 is hydrogen atom, a halogen atom, alkyl group, or the like, each of X4 , X5 is hydrogen atom, an alkyl group, aryl group, or the like, and X6 is hydrogen atom or methyl group.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming method, and more particularly to an image forming method in which a contact charging device and a photoconductor are combined.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic apparatus such as a plain paper copying machine (PPC), a laser printer, an LED printer, a liquid crystal printer, etc., an image forming process of charging, exposing and developing a photosensitive member such as a rotating drum type. Is applied to form an image, which is transferred to a transfer material and then fixed to obtain a copy. Photoreceptors used in these electrophotographic devices include selenium, arsenic-selenium, cadmium sulfide,
Although inorganic photoconductors such as zinc oxide and a-Si are used, research and development of organic photoconductors (OPC) that are inexpensive and excellent in terms of manufacturability and disposability are also active. Since a so-called function-separated type laminated photoconductor in which a charge transport layer and a charge transport layer are laminated is excellent in electrophotographic characteristics such as sensitivity, chargeability, and repeated stability thereof, various proposals have been made and practical use thereof has been made. Has been done. As a charging device for these photoconductors, a corona charging device having a thin wire electrode such as a gold-plated tungsten wire and a shield plate as main constituent members is widely used as a general one.

However, these corona charging devices have the following problems. 1) In order to obtain a surface potential of 500 to 700 V with the image holding member, it is necessary to apply a high voltage of DC 4 KV or more to the wire electrode, and in order to prevent leakage to the shield plate or the main body, Since it is necessary to take measures such as maintaining a large distance between the shield plates, the size of the apparatus itself becomes large, and the use of a high voltage cable or the like is indispensable, which further increases the cost. 2) A considerable amount of ozone is generated with corona discharge,
Nitrogen in the air is oxidized to generate nitrogen oxides (NO _x ), and the nitrogen oxides react with water in the air to generate nitric acid and the like. In particular, these discharge products adhere or act on the surface of the photoconductor to cause alteration, deterioration, etc., which lowers the resistance of the photoconductor and causes image blurring. Also, in view of environmental problems in recent years, these discharge products are considered to be unfavorable, and in order to remove them, it is indispensable to use an exhaust fan, a filter, etc., which further increases the cost. . Therefore, recently, instead of using the corona charging device having many of these problems, a contact charging method, that is, a conductive member to which a voltage is applied is brought into contact with the surface of the photoconductor to directly inject the charge into the surface of the photoconductor. Various contact charging methods for obtaining a desired charging potential have been proposed (JP-A-63-149669, etc.).

[0004]

However, when these contact charging methods are applied to the conventional function-separated type organic photoconductor, the following problems occur. That is, 1) In general, a charge transport layer in which a low molecular weight charge transport material is molecularly dispersed in a polymer binder resin is used on the outermost surface.
In that case, the charging member will be repeatedly used in a state of being in direct contact with the charge transport layer, and as a result, the charge transport layer will be significantly worn away, causing a decrease in charging property, a change in sensitivity, etc. The life of the photoconductor becomes extremely shorter than that when it is used. That is, even a photoconductor that can be used without any problem by corona charging tends to cause image defects due to abrasion or the like when applied to contact charging. 2) Further, the direct contact makes it easier for foreign matter to adhere to the surface of the photoconductor, contamination, etc., and image defects caused by the foreign matter appear on the copy. There are various possible causes of problems such as abrasion of the photosensitive layer and adhesion of foreign matter to the surface of the photoconductor. One of them is that a low molecular weight charge transport material is dispersed in the binder resin. In the charge transport layer, the charge directly flows locally at the time of contact charging, so that not only the surface of the photoconductor is stressed, but also in the method using not only the DC voltage but the AC voltage, the charge transport material is deeper. It is considered that the deterioration of the binder resin is promoted. Further, if the charge transport material is locally non-uniformly dispersed, these deteriorations are also non-uniform, so that the film strength of the photosensitive layer is lowered and abrasion is increased, while non-uniform deterioration is caused by foreign matter. It is thought that it also forms nuclei for attaching the. The present invention has been made for the purpose of solving the above-mentioned problems in the conventional technique. That is, an object of the present invention is to provide an image forming method that is excellent in abrasion resistance even when a contact charging method is applied, and as a result, foreign substances are less likely to be attached and contaminated on the surface of the photoconductor and the occurrence of image quality defects can be reduced. To provide.

[0005]

The inventors of the present invention have conducted extensive studies to solve the above-mentioned problems, and as a result, even in the contact charging method, a photosensitive body containing a specific binder resin in the photosensitive layer was used. The inventors have found that the use of the photosensitive layer causes less abrasion and that the image quality defect due to the adhesion of foreign matter is less likely to occur, and thus the present invention has been completed. That is, the image forming method of the present invention is to form a visible image by developing an electrostatic charge image on a photoconductor after charging the photoconductor, and a visible image is formed on the electroconductive support as a photoconductor. The one in which a photosensitive layer containing a polycarbonate resin selected from the following (I) to (III) is provided as a binder resin is used, and the step of charging the photosensitive member is conducted by contacting the surface of the photosensitive member. It is characterized by a contact charging device for applying a voltage to the elastic member.

(I) A polycarbonate resin comprising a repeating structural unit represented by the following formula,

[Chemical 4]

(II) a copolymerized polycarbonate resin comprising repeating structural units represented by the following formulas (A) and (B),

[Chemical 5] (In the formula, X and X ′ each represent a hydrogen atom, a halogen atom or a methyl group, R represents a hydrogen atom, a halogen atom, a hydroxyl group, a carboxyl group, an acetyl group or an alkyl group having 1 to 4 carbon atoms, and j represents It means an integer of 1 to 3.)

And (III) A copolycarbonate resin comprising repeating structural units represented by the following formulas (C), (D) and (E).

[Chemical 6] (In the formula, R represents a hydrogen atom, a methyl group or an aryl group, and X ₁ , X ₂ and X ₃ each represent a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an aryl-substituted alkyl group, or a cyclohexyl group, X ₄ and X ₅
Are the same or different and each represents a hydrogen atom, an alkyl group, an aryl group, an aryl-substituted alkyl group, or a bicycloalkane group, provided that the formula (C)
Or X ₄ and X ₅ together represent an atomic group necessary for forming a carbocycle or a lactone ring, and X ₆ represents a hydrogen atom or a methyl group. )

The present invention will be described in detail below. In the photoconductor used in the present invention, the photosensitive layer may have a single-layer structure or a function-separated laminated structure. 2 to 5 are schematic cross-sectional views of the photoconductor of the present invention. 2 and 3 show a case where the photosensitive layer has a single-layer structure, and the photosensitive layer 1 is formed on the conductive support 13.
1 is provided, and in FIG.
Is provided. 4 and 5 show a case where the photosensitive layer has a laminated structure. In FIG.
The charge generation layer 14 and the charge transport layer 15 are formed on the conductive support 13.
Are sequentially provided, and in FIG. 5, an undercoat layer 12 is further provided on the conductive support 13. Hereinafter, the case where the photosensitive layer has a laminated structure will be mainly described.

Examples of the conductive support include metals such as aluminum, nickel, chromium and stainless steel, as well as aluminum, titanium, nickel, chromium, stainless steel, gold, vanadium, tin oxide, indium oxide and IT.
Examples thereof include a plastic film provided with a thin film such as O, paper coated with or impregnated with a conductivity-imparting agent, and a plastic film. These conductive supports are used in a suitable shape such as a drum shape, a sheet shape, and a plate shape, but are not limited thereto. Further, if necessary, the surface of the conductive support is
Various types of processing can be performed within a range that does not affect the image quality. For example, surface oxidation treatment, chemical treatment, coloring treatment, or irregular reflection treatment such as graining can be performed.

An undercoat layer may be further provided between the conductive support and the charge generation layer. The subbing layer functions as an adhesive layer that prevents injection of electric charges from the conductive support to the photosensitive layer during charging of the photosensitive layer having a laminated structure and integrally adheres and holds the photosensitive layer to the conductive support. Or, depending on the case, the function of preventing the reflected light of the conductive support from being reflected. Materials used for the undercoat layer include polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polycarbonate resin, polyurethane resin, polyimide resin, vinylidene chloride resin, polyvinyl resin. Acetal resin, vinyl chloride-
Vinyl acetate copolymer, polyvinyl alcohol resin, water-soluble polyester resin, nitrocellulose, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, polyacrylic acid, polyacrylamide, zirconium chelate compound, titanyl chelate compound, titanyl alkoxide Known materials such as compounds, organic titanyl compounds, and silane coupling agents can be used, and these materials can be used alone or in combination of two or more. Further, it can be used as a mixture with fine particles such as titanium oxide, silicon oxide, zirconium oxide, barium titanate and silicone resin. The thickness of the undercoat layer is 0.01 to 10 μm, preferably 0.05 to 2 μm.
m is suitable, and as the coating method, there are blade coating method, Meyer bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, curtain coating method and the like which are used for ordinary coating. Can be used.

As the charge generating material in the charge generating layer, amorphous selenium, crystalline selenium-tellurium alloy, selenium-arsenic alloy, other selenium compounds and selenium alloys,
Inorganic photoconductive materials such as zinc oxide and titanium oxide, phthalocyanine series, squarylium series, anthanthrone series,
Organic pigments and dyes such as perylene type, azo type, anthraquinone type, pyrene type, pyrylium salt and thiapyrylium salt are used. As the binder resin, polyvinyl butyral resin, polyvinyl formal resin, partially modified polyvinyl acetal resin, polycarbonate resin, polyester resin, acrylic resin, polyvinyl chloride resin, polystyrene resin, polyvinyl acetate resin, polyvinyl chloride-vinyl acetate copolymer , Silicone resin, phenol resin, poly-N-vinylcarbazole resin, and the like, but are not limited thereto. These binder resins may be used alone or in combination of two or more. The compounding ratio (weight ratio) of the charge generating material and the binder resin is
The range of 10: 1 to 1:10 is preferable. The thickness of the charge generation layer used in the present invention is generally 0.1 to 5 μm.
m, preferably 0.2 to 2.0 μm. As a coating method, a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, a curtain coating method or the like which is generally used can be used. Further, as a solvent used when providing the charge generation layer, methanol,
Organic solvents such as ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride and chloroform may be used alone or. Two or more kinds can be mixed and used.

The charge transport layer is formed by making the charge transport material compatible with the binder resin made of the polycarbonate resin selected from the above (I) to (III). Examples of the charge transport material include quinone compounds such as p-benzoquinone, chloranil, bromoanil and anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, xanthone compounds and benzophenone compounds. Compound, cyanovinyl compound,
Electron withdrawing substances such as ethylene compounds, triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, hydrazone compounds, or groups consisting of these compounds Examples thereof include electron-donating substances such as polymers having a main chain or side chains.
These charge transport materials can be used alone or in combination of two or more.

Particularly, a benzidine compound represented by the following structural formula (IV), a triarylamine compound represented by the structural formula (V), or a mixture thereof is preferable.

[Chemical 7] (In the formula, R ₂ and R ₂ ′ each represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group,
R ₃ , R ₃ ′, R ₄ and R ₄ ′ may be the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or a substituted amino group, and m and n are each 0 to 0. Represents an integer of 2. )

[0015]

Embedded image (In the formula, Ar ₁ and Ar ₂ are each a phenyl group which may be substituted with an alkyl group, a phenyl group, an alkoxy group or an alkyl-substituted phenyl group, a polycyclic aromatic group which may be substituted with an alkoxy group, or an aromatic heterocyclic group. Represents a ring group.)

Specific examples of the benzidine compound represented by the structural formula (IV) are shown in Tables 1 and 2.

[Table 1]

[0017]

[Table 2]

Specific examples of the triarylamine compound represented by the structural formula (V) are shown in Tables 3 to 6.

[Table 3]

[0019]

[Table 4]

[0020]

[Table 5]

[0021]

[Table 6]

The polycarbonate resin represented by the above formulas (I) to (III) has a viscosity average molecular weight of 10,000 to 20.
Anything in the range of ten thousand can be used. When the viscosity average molecular weight is less than 10,000, the viscosity of the coating solution is low, the required film thickness cannot be obtained, and uneven film thickness occurs when dip coating is applied. There is a problem that the viscosity of the coating liquid is too high and it becomes difficult to control the required film thickness. Even in the case where the viscosity average molecular weight is 10,000 to 20,000, the formed coating film has low mechanical strength and poor abrasion resistance, and therefore, it is preferably in the range of 20,000 to 100,000. More preferably, it is in the range of 30,000 to 70,000. In the present invention, it is preferable to use a polycarbonate resin having a relatively uniform molecular weight distribution, but if the viscosity average molecular weight is in the range of 10,000 to 200,000, polycarbonate resins having different viscosity average molecular weights are mixed appropriately. You may use. Further, it is also possible to use one obtained by mixing or further copolymerizing another polycarbonate resin within a range that does not impair the action and effect of the polycarbonate resin.

In the case of the above-mentioned copolymerized polycarbonate resin (II), the following are preferable specific examples of the repeating unit represented by the formula (B).

[Chemical 9] Further, the repeating structural unit represented by the formula (A) and the formula (B)
It is effective that the copolymerization ratio of the repeating structural units represented by is in the range of (A) :( B) = 1: 19 to 19: 1 in terms of molar ratio, and more preferably (A) :( B) = 1: 9-4:
The range is 1.

Further, in the case of the copolymerized polycarbonate resin of (III), the following are preferable specific examples of the repeating units represented by the formulas (C), (D) and (E).
In addition, regarding the formula (D), the groups X ₂ , X ₃ , X ₄ , X
₅ is shown in Tables 7-11.

[Chemical 10]

[0025]

[Chemical 11]

[0026]

[Table 7]

[0027]

[Table 8]

[0028]

[Table 9]

[0029]

[Table 10]

[0030]

[Table 11] The copolymerization ratio of the repeating units represented by the formulas (C), (D) and (E) is a molar ratio of C: D: E = 5 to 50:20.
To 70:10 to 40 are preferable, and 25 to 40:30 is particularly preferable.
55: 20-35 are preferable.

The composition ratio of the charge transport material to the binder resin is preferably in the range of 10:90 to 70:30 by weight, and 3
The range of 0:70 to 60:40 is particularly preferable. The thickness of the charge transport layer used in the present invention is generally 5 to 50 μm,
It is preferably 10 to 30 μm. As a coating method, a usual method such as a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method and a curtain coating method can be used. Further, as a solvent used when providing the charge transport layer, aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene, ketones such as acetone and 2-butanone, halogenated methylene chloride, chloroform and ethylene chloride. Examples of commonly used organic solvents include aliphatic hydrocarbons, cyclic or linear ethers such as tetrahydrofuran and ethyl ether, and these may be used alone or in combination of two or more.

Further, in order to prevent the deterioration of the photoreceptor due to ozone or oxidizing gas generated in the copying machine, or light or heat, an antioxidant, a light stabilizer, a heat stabilizer, etc. are contained in the charge transport layer. Additives can be added. Examples of antioxidants include hindered phenols, hindered amines, paraphenylenediamines, aryl alkanes, hydroquinones, spirochromans, spiroindanones and their derivatives, organic sulfur compounds and organic phosphorus compounds. Examples of the light stabilizer include benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine derivatives. Further, at least one electron-accepting substance can be contained for the purpose of improving sensitivity, reducing residual potential, and reducing fatigue during repeated use. Examples of the electron accepting substance that can be used in the present invention include, for example, succinic anhydride, maleic anhydride,
Dibromo maleic anhydride, phthalic anhydride, tetrabromo phthalic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-dinitrobenzene, chloranil, dinitroanthraquinone, trinitrofluorenone, picric acid, o-nitrobenzoic acid Acid, p
Examples thereof include nitrobenzoic acid and phthalic acid.
Of these, fluorenone series, quinone series, Cl, C
A benzene derivative having an electron-withdrawing substituent such as N or NO ₂ is particularly preferable. In the present invention, an additive can be added to the charge transport layer mainly for the purpose of obtaining good surface property. As this type of additive, those known as modifiers for paints can be used. For example, alkyl-modified silicone oil such as dimethyl silicone oil, aromatic modified silicone oil such as methylphenyl silicone oil, etc. are preferable examples. These additives are added in an amount of 1 to 10 relative to the solid content of the charge transport layer.
000 ppm, preferably 5-2,000 ppm may be added.

Although the case where the photosensitive layer has a laminated structure has been described above, when the photosensitive layer has a single layer structure, the photoconductive material is dispersed or dissolved in the polycarbonate resin selected from the above (I) to (III). Then, the photosensitive layer may be formed. The image forming method of the present invention, after charging the photoreceptor,
A contact charging device comprising a step of forming an electrostatic image on a photoreceptor and forming a visible image by development, and the step of charging the photoreceptor applies a voltage to a conductive member brought into contact with the surface of the photoreceptor. It is due to.

FIG. 1 is a schematic block diagram of an example of an electrophotographic copying apparatus for carrying out the image forming method of the present invention. Around the electrophotographic photosensitive member 1, a contact charging device 2, an exposure device 3, a developing device 4, a transfer device 5 and a cleaning device 6 are arranged. The electrophotographic photosensitive member 1 rotates in the direction of the arrow and is uniformly charged by the contact charging device 2, and then imagewise exposed by the exposure device 3, and the formed electrostatic latent image is then tonered by the developing device 4. Is visualized by. Then
A transfer device 5 such as a corona charger transfers the toner image onto the transfer paper 7, and a fixing device 8 fixes the toner image. The toner remaining on the surface of the electrophotographic photosensitive member 1 is cleaned by a cleaning device 6 equipped with a blade cleaner or the like. In the present invention, the electrophotographic photosensitive member after cleaning is uniformly charged by the contact charging device 2 in the next charging step as it is without passing through the charge removing step, and image formation is performed as described above.

In the present invention, the conductive member used in the contact charging device may have any shape such as a brush shape, a blade shape, a pin electrode shape, or a roller shape, but it is particularly preferable to use a roller shape member. Usually, the roller-shaped member is composed of an outer resistance layer, an elastic layer supporting them, and a core material. Further, a protective layer may be provided on the surface of the resistance layer if necessary. As the substance of the core material, any substance having conductivity can be used,
Generally, iron, copper, brass, stainless steel, aluminum,
Nickel or the like is used. In addition, a resin molded product in which conductive particles or the like are dispersed may be used. As the material of the elastic layer, any material having conductivity or semiconductivity can be used, and generally, a material in which conductive particles or semiconductive particles are dispersed in a rubber material is used. It As the rubber material, EPDM, polybutadiene, natural rubber, polyisobutylene, SBR, C
R, NBR, silicone rubber, urethane rubber, epichlorohydrin rubber, SBS, thermoplastic elastomer, norbornene rubber, fluorosilicone rubber, ethylene oxide rubber and the like are used. As the conductive particles or semi-conductive particles, carbon black, zinc, aluminum,
Metals such as copper, iron, nickel, chromium and titanium, Zn
_{O-Al 2 O 3, SnO} 2 -Sb 2 O 3, In 2 O 3 -
_{SnO 2, ZnO-TiO 2,} MgO-Al 2 O 3, F
_{eO-TiO 2, TiO 2,} SnO 2, Sb 2 O 3, I
A metal oxide such as n ₂ O ₃ , ZnO or MgO can be used. These materials may be used alone or as a mixture of two or more kinds, and when two or more kinds are used, one of them may be in the form of fine particles. Further, as the fine particles, fine particles of fluorine resin can be used.

As the material of the resistance layer and the protective layer, a material in which conductive particles or semiconductive particles are dispersed in a binder resin and the resistance thereof is controlled is used. Resistivity is 10 ³ ~
The range is 10 ¹⁴ Ωcm, preferably 10 ⁵ to 10 ¹² Ωcm, and more preferably 10 ⁷ to 10 ¹² Ωcm.
The film thickness is 0.01 to 1000 μm, preferably 0.1.
The range of 1 to 500 μm, more preferably 0.5 to 100 μm is adopted. As the binder resin, acrylic resin,
Cellulose resin, polyamide resin, methoxymethylated nylon, ethoxymethylated nylon, polyurethane resin, polycarbonate resin, polyester resin, polyethylene resin, polyvinyl resin, polyarylate resin, polythiophenone resin, polyethylene terephthalate (P
ET), polyolefin resin, styrene-butadiene resin, etc. are used. As the conductive particles or the semiconductive particles, the same carbon black, metal and metal oxide as those used for the elastic layer can be used. If necessary, antioxidants such as hindered phenol and hindered amine, fillers such as clay and kaolin, and lubricants such as silicone oil can be added. As means for forming these layers, blade coating method, Mayer bar coating method, spray coating method, dip coating method, bead coating method, air knife coating method, curtain coating method, vacuum vapor deposition method, plasma coating method, etc. A coating method can be used.

As a method of charging the photoconductor using these conductive members, a voltage is applied to the conductive members.
As the applied voltage, it is difficult to obtain uniform charging with only the DC voltage, and therefore it is preferable to apply the AC voltage on the DC voltage. As for the voltage range, the DC voltage is preferably positive or negative 50 to 2000 V, particularly 100 to 150 V.
0V is preferred. The AC voltage to be superimposed is a peak-to-peak voltage of 400 to 1800 V, preferably 800 to 1600.
V, more preferably in the range of 1200 to 1600V is adopted. AC voltage frequency is 100 ~ 2000H
z is preferred. The photoconductor uniformly charged by contact charging then forms an electrostatic latent image by a conventional method. As the latent image forming means, any known means can be used. Then, the formed electrostatic latent image is developed with a developer to form a visible image and is transferred to a transfer material to form a copied image.

[0038]

EXAMPLES The present invention will be described below with reference to examples. In the examples, "part" means "part by weight". Example 1 A solution containing 10 parts of a zirconium compound (Organix ZC540, manufactured by Matsumoto Pharmaceutical Co., Ltd.) and 1 part of a silane compound (A1110, manufactured by Nippon Unicar Co.), 40 parts of i-propanol and 20 parts of butanol was immersed in an aluminum pipe. It was applied by a coating method and heated and dried at 150 ° C. for 10 minutes to form an undercoat layer having a film thickness of 0.1 μm. Next, 1 part of X-type metal-free phthalocyanine crystal was mixed with 1 part of polyvinyl butyral resin (S-REC BM-S, manufactured by Sekisui Chemical Co., Ltd.) and 100 parts of cyclohexanone, treated with a glass mill for 1 hour in a sand mill, and dispersed. The obtained coating liquid was applied onto the above-mentioned undercoat layer by a dip coating method, and dried by heating at 100 ° C. for 10 minutes to form a charge generation layer having a film thickness of 0.15 μm.
Subsequently, a coating solution obtained by dissolving 2 parts of the benzidine compound of the exemplified compound (IV-27) and 3 parts of the polycarbonate resin of (I) (viscosity average molecular weight of 60000) in 20 parts of chlorobenzene was used. It was applied on the generating layer by a dip coating method and heated at 110 ° C. for 40 minutes to form a charge transporting layer having a film thickness of 25 μm to obtain a photoreceptor. As a core material, 6
Using a stainless steel rod with a diameter of 10 mm, the resistance of the elastic layer is 10
Conductive EPDM rubber of ⁶ Ωcm is used as the resistance layer.
12 mm using epichlorohydrin rubber of ⁰⁹ Ωcm
A conductive roll having a diameter was prepared.

The photosensitive member and the conductive roll thus obtained were combined with a laser beam printer (XP-11 modified machine,
Mounted on Fuji Xerox Co., Ltd., DC as bias:
Image quality was evaluated by applying −550 V, AC: 1000 V _PP / 800 Hz, charging and image formation.
After that, this image formation was repeated 50,000 times, the image quality after 50,000 times was evaluated, and the wear amount of the charge transport layer was measured. The results are shown in Table 1.
It is shown in FIG.

Example 2 In the photoreceptor of Example 1, the charge transport layer (I) was used.
Instead of the polycarbonate resin of, the following structural formula (A)
A photoconductor was prepared in the same manner as in Example 1 except that the copolymerized polycarbonate resin consisting of the repeating structural units represented by (B-1) and (B-1) was used. The molar ratio of the repeating structural unit represented by Structural Formula (A) to the repeating structural unit represented by Structural Formula (B-1) was about 1: 1 and the viscosity average molecular weight was 50,000. Using this photoconductor, evaluation was performed in the same manner as in Example 1. The results are shown in Table 12.

[Chemical 12]

Example 3 In the photoreceptor of Example 1, the charge transport layer (I) was used.
Instead of the polycarbonate resin of
A photoreceptor was prepared in the same manner as in Example 1 except that the copolymerized polycarbonate resin consisting of the repeating structural units represented by 3), (D-23) and (E-1) was used. The ratio of each repeating structural unit in the copolymerized polycarbonate resin was 1: 1: 1 and the viscosity average molecular weight was 40,000. Using this photoconductor, evaluation was performed in the same manner as in Example 1. The results are shown in Table 12.

[Chemical 13]

Comparative Example 1 A photoconductor was prepared in the same manner as in Example 1 except that a polycarbonate resin represented by the following structural formula (VI) was used as the binder resin for the charge transport layer in Example 1. Was evaluated. The evaluation results are shown in Table 12.

Embedded image

[0043]

[Table 12]

Examples 4 to 6 In each of the photoreceptors of Examples 1 to 3, the exemplified compound (V-14) was used in place of the benzidine compound of the exemplified compound (IV-27) in the charge transport layer. Other than the above, a photoconductor was manufactured in the same manner, and only the one by the contact charging method among the similar evaluations was performed. The results are shown in Table 13.

Example 7 In the photoreceptor of Example 4, the charge transport layer (I) was used.
Instead of the polycarbonate resin of, the following structural formula (A)
A photoconductor was prepared in the same manner as in Example 4, except that the copolymerized polycarbonate resin consisting of the repeating structural units represented by (B-6) and (B-6) was used. The molar ratio of the repeating structural unit represented by the structural formula (A) to the repeating structural unit represented by the structural formula (B-6) was about 1: 1 and the viscosity average molecular weight was 50,000. Using this photoconductor, evaluation was performed in the same manner as in Example 1. The results are shown in Table 13.

[Chemical 15]

[0046]

[Table 13]

As is clear from the results shown in Tables 12 and 13, the image forming method of the example maintains a good image quality even after printing 50,000 sheets, whereas in Comparative Example 1 in which only the photoconductor is changed. Image defects frequently occurred due to abrasion marks on the surface of the photoconductor. From these facts, in the image forming method of the present invention using the photoreceptor using the polycarbonate resin selected from the above (I) to (III) in the image forming method by the contact charging method, the abrasion of the photoreceptor is caused. It can be seen that the amount can be significantly reduced and the life of the image forming apparatus can be improved.

[0048]

As is apparent from the above comparison, the image forming method of the present invention has less wear on the photoconductor, can improve the life of the image forming apparatus, and can prevent foreign matter from being left on the surface of the photoconductor. Since there is little adhesion or contamination, it is possible to reduce the occurrence of image quality defects, and it is possible to obtain a copied image with excellent image quality for a long period of time.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus for carrying out the present invention.

FIG. 2 is a schematic cross-sectional view of an example of a photoconductor of the present invention.

FIG. 3 is a schematic cross-sectional view of another example of the photoconductor of the present invention.

FIG. 4 is a schematic cross-sectional view of another example of the photoconductor of the present invention.

FIG. 5 is a schematic cross-sectional view of another example of the photoconductor of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electrophotographic photoreceptor, 2 ... Contact charging device, 3 ... Exposure device, 4 ... Developing device, 5 ... Transfer device, 6 ... Cleaning device, 7 ... Transfer paper, 8 ... Fixing device, 11 ... Photosensitive layer, 12 ...
Undercoat layer, 13 ... Conductive support, 14 ... Charge generation layer, 1
5 ... Charge transport layer.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tomoo Kobayashi 1600 Takematsu, Minamiashigara-shi, Kanagawa Fuji Xerox Co., Ltd. (72) Toru Ishii 1600 Takematsu, Minamiashigara-shi, Kanagawa Fuji Xerox Co., Ltd.

Claims (3)

[Claims] 1. An image forming method of forming a visible image by developing an electrostatic charge image on a photoreceptor after charging the photoreceptor, and the following (I) is formed on the conductive support as the photoreceptor. ) To (III) is used to provide a photosensitive layer containing a polycarbonate resin selected as a binder resin, and the step of charging the photosensitive member is performed by applying a voltage to the conductive member brought into contact with the surface of the photosensitive member. An image forming method using a contact charging device that applies a voltage. (I) A polycarbonate resin having a repeating structural unit represented by the following formula: (II) Copolymerized polycarbonate resin composed of repeating structural units represented by the following formulas (A) and (B): (In the formula, X and X ′ each represent a hydrogen atom, a halogen atom or a methyl group, R represents a hydrogen atom, a halogen atom, a hydroxyl group, a carboxyl group, an acetyl group or an alkyl group having 1 to 4 carbon atoms, and j represents Means an integer of 1 to 3) and (III) the following formulas (C), (D) and (E)
A copolymeric polycarbonate resin having a repeating structural unit represented by: [Chemical 3] (In the formula, R represents a hydrogen atom, a methyl group or an aryl group, and X ₁ , X ₂ and X ₃ each represent a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an aryl-substituted alkyl group, or a cyclohexyl group, X ₄ and X ₅
Are the same or different and each represents a hydrogen atom, an alkyl group, an aryl group, an aryl-substituted alkyl group, or a bicycloalkane group, provided that the formula (C)
Or X ₄ and X ₅ together represent an atomic group necessary for forming a carbocycle or a lactone ring, and X ₆ represents a hydrogen atom or a methyl group. ) 2. The image forming method according to claim 1, wherein the photoreceptor is a laminated photoreceptor, and the outermost surface layer thereof contains a polycarbonate resin selected from the above (I) to (III). 3. The image forming method according to claim 2, wherein the outermost surface layer is a charge transport layer.