JP2001092161A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electrophotographic photoreceptor having improved lubricity without impairing electrical characteristics. SOLUTION: The electrophotographic photoreceptor has at least a photosensitive layer on an electrically conductive substrate. The photosensitive layer contains a charge generating material, a charge transferring material, a polycarbonate resin and a wax having an ester group. The polycarbonate resin contains bisphenol replaced by a monovalent organic residue containing the ester of a >=4C aliphatic alcohol and a >=1C carboxylic acid as constituent components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor having excellent surface sliding properties, sliding properties and electrical properties.

[0002]

2. Description of the Related Art In recent years, electrophotographic technology has been widely used and applied not only in the field of copying machines but also in the field of various printers because of its immediacy and high-quality images. Photoconductors, which are the core of electrophotographic technology, have been formed from conventional inorganic photoconductors such as selenium, arsenic-selenium alloy, cadmium sulfide, and zinc oxide as photoconductive materials. A photoreceptor using an organic photoconductive material having advantages such as easy and easy production has been developed. Among the organic photoconductors, a so-called stacked photoconductor in which a charge generation layer and a charge transport layer are stacked is mainly used. However, organic laminated photoreceptors have sufficient performance in terms of electrical characteristics such as sensitivity and chargeability, but are insufficient in physical strength of the photoreceptor surface, so that the practical upper limit was set. At present, printing performance is limited. It is the mechanical properties of the charge transport layer in the laminated photoreceptor that substantially determine the physical strength of the photoreceptor surface.

In order to increase the mechanical strength, for example, an overcoat layer is provided (JP-A-61-72256).
JP-A-63-148263 and JP-A-3-22.
No. 1962) have been proposed, but all of them present a problem that these effects are not sufficient or adversely affect characteristics such as electric characteristics.

[0004] In recent years, there has been a demand for improvement in surface slipperiness because of the need to withstand various increases in physical load on the photoreceptor and to provide high-quality images that are stable over a long period of time.
Regarding the improvement of the surface slipperiness by the binder resin,
Using a polysiloxane block copolymer as a binder (JP-A-61-132954, JP-A-2-240)
655), a low molecular weight polysiloxane terminal compound is used (JP-A-7-261440), and a fluorine atom-containing polycarbonate is used (JP-A-5-3063).
No. 35, JP-A-6-32884, JP-A-6-32884
No. 282094), and a polycarbonate having an alkyl group in a side chain is used (JP-A-7-13363).
However, at present, there are problems such as insufficient effects and adverse effects on electrical characteristics and printing durability.

On the other hand, in order to improve the surface slipperiness by a composition other than the binder resin, a method of dispersing an inorganic filler or lubricating particles in the charge transport layer has been devised, but the incident light is scattered by the particles. Therefore, there is a problem that the sensitivity is greatly deteriorated depending on the type and amount of the particles.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a method for controlling the slippage and slidability of the surface of a photoreceptor without adversely affecting electrical characteristics.
This is to improve the scratch resistance.

[0007]

In view of these circumstances, the present inventor has focused on the slipperiness of the photoreceptor surface among the mechanical strengths, and has reduced the contact resistance with the cleaning blade and the developer as much as possible. As a result of diligent studies on techniques to enhance the slipperiness of the photoreceptor surface in order to minimize mechanical damage to the photoreceptor, a combination of a polycarbonate resin with an alkyl ester group and a wax with an ester group was used in the photosensitive layer By doing so, it has been found that the surface slipperiness is significantly increased without impairing other characteristics, and that an electrophotographic photoreceptor having excellent cleaning properties and durability against scratches with little decrease in electrical properties even after long-term repeated use is provided. The present invention can be performed. That is, the gist of the present invention is to provide an electrophotographic photoreceptor having at least a photosensitive layer on a conductive substrate, wherein the photosensitive layer contains a charge generating substance, a charge transporting substance, a polycarbonate resin and a wax having an ester group, and The polycarbonate resin is composed of an aliphatic alcohol having 4 or more carbon atoms and 1 carbon atom.
An electrophotographic photoreceptor characterized in that it contains, as a constituent, bisphenol substituted with a monovalent organic residue containing a carboxylic acid ester.

[0008]

The gist of the present invention is that a specific polycarbonate resin and a wax are used in combination. First, as the polycarbonate resin, a resin containing bisphenol substituted with a monovalent organic residue containing an ester of an aliphatic alcohol having 4 or more carbon atoms and a carboxylic acid having 1 or more carbon atoms is used. In particular,
It is represented by the following general formula (1).

[0009]

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In the general formula (1), X is

[0011]

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An aromatic ring, a single bond, a lactone or fluorene is shown. Y ¹ , Y ² , Y ³ , Y ⁴ , Y ⁵ , Y ⁶ , Y ⁷ , Y
⁸ , Y ⁹ and Y ¹⁰ each independently preferably contain at least one monovalent organic residue containing an ester of an aliphatic alcohol having 4 or more carbon atoms and a carboxylic acid having 1 or more carbon atoms, and further include a hydrogen atom, chlorine Atom, bromine atom, fluorine atom, methyl group, ethyl group, n-propyl group, isopropyl group, sec-butyl group, n-butyl group, isobutyl group, tert-butyl group, allyl group, phenyl group, and methoxy group are used. And
More preferably, at least one monovalent organic residue containing an ester of an aliphatic alcohol having 4 or more carbon atoms and a carboxylic acid having 1 or more carbon atoms, and a hydrogen atom, a methyl group, or a phenyl group are used.

The aliphatic alcohol moiety of the monovalent organic residue containing an ester group of an aliphatic alcohol having 4 or more carbon atoms and a carboxylic acid having 1 or more carbon atoms may be linear or branched, but is preferably a carbon atom. The number is 10 or more, more preferably 15 or more and 30 or less. If the number of carbon atoms is 4 or less, a sufficient slippage improving effect may not be obtained, and if the number of carbon atoms is more than 30, solubility and other mechanical properties may be adversely affected. The carboxylic acid moiety having 1 or more carbon atoms of the ester is preferably an aliphatic or aromatic carboxylic acid having 1 to 10 carbon atoms, and more preferably 1 to 3 carbon atoms.
The following aliphatic carboxylic acids are used. In the aforementioned general formula (1), X is preferably

[0014]

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Wherein Y ⁹ and Y ¹⁰ are preferably
Methyl group, ethyl group, n-propyl group, isopropyl group, phenyl group, cyclohexyl group, a monovalent organic residue containing an ester of an aliphatic alcohol having 4 or more carbon atoms and a carboxylic acid having 1 or more carbon atoms is used, More preferably, a monovalent organic residue containing a methyl group, a phenyl group, or an ester of an aliphatic alcohol having 4 or more carbon atoms and a carboxylic acid having 1 or more carbon atoms is used. The aliphatic alcohol portion of a monovalent organic residue containing an ester group of an aliphatic alcohol having 4 or more carbon atoms and a carboxylic acid having 1 or more carbon atoms may be linear or branched, but preferably has 10 or more carbon atoms. More preferably, it has from 15 to 30 carbon atoms.

The content of the aliphatic alcohol portion of the ester group contained in the polycarbonate of the present invention is preferably 1% by weight or more and 50% by weight or less, more preferably 5% by weight or less.
It is at least t% and at least 30 wt%. If the amount is less than 1 wt%, a sufficient effect of improving slipperiness cannot be obtained, and if it is more than 50 wt%, heat resistance is undesirably reduced. The structural unit represented by the general formula (1) may be a single unit, or may include one or more other structural units.
A copolymer with a functional phenol compound may be used. Specific examples of the bifunctional phenol compound that provides another copolymer component include bis- (4-hydroxyphenyl) methane,
1,1-bis- (4-hydroxyphenyl) ethane,
1,1-bis- (4-hydroxyphenyl) propane,
2,2-bis- (4-hydroxyphenyl) propane,
2,2-bis- (4-hydroxyphenyl) butane,
2,2-bis- (4-hydroxyphenyl) pentane,
2,2-bis- (4-hydroxyphenyl) -3-methylbutane, 2,2-bis- (4-hydroxyphenyl)
Hexane, 2,2-bis- (4-hydroxyphenyl)
-4-methylpentane, 1,1-bis- (4-hydroxyphenyl) cyclopentane, 1,1-bis- (4-hydroxyphenyl) cyclohexane, bis- (4-hydroxy-3-methylphenyl) methane, , 1-bis-
(4-hydroxy-3-methylphenyl) ethane, 2,
2-bis- (4-hydroxy-3-methylphenyl) propane, 2,2-bis- (4-hydroxy-3-ethylphenyl) propane, 2,2-bis- (4-hydroxy-3-isopropylphenyl) Propane, 2,2-bis- (4-hydroxy-3-sec-butylphenyl) propane, bis- (4-hydroxyphenyl) phenylmethane, 1,1-bis- (4-hydroxyphenyl) -1
-Phenylethane, 1,1-bis- (4-hydroxyphenyl) -1-phenylpropane, bis- (4-hydroxyphenyl) diphenylmethane, bis- (4-hydroxyphenyl) dibenzylmethane, 4,4′-dihydroxy Examples thereof include diphenyl ether, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenylsulfide, and phenolphthalein.

The repeating unit represented by the general formula (1) is
One type or a combination of two or more types of repeating units may be used. Further, other structures such as polyester, polyarylate, polyamide, polyacetal, polyurethane, polyimide, polyether, polyketone, polyvinyl polymer, and polysiloxane may be introduced as long as the characteristics are not substantially changed. Further, a polycarbonate containing the structural unit of the general formula (1) and a polycarbonate having another structure may be mixed and used at an arbitrary ratio. In this case, the polycarbonate containing the structural unit of the general formula (1) is preferably 10% by weight or more and 100% or less, more preferably 30% by weight or less.
% Or more and 90 wt% or less. If the content is less than 10 wt%, a sufficient improvement effect cannot be obtained.

The polycarbonate polymer used in the present invention preferably has a viscosity average molecular weight of 10,000 or more and 30 or more.
5,000 or less, more preferably 15,000
Or more and 100,000 or less, particularly preferably 20,000 or more and 60,000 or less. Viscosity average molecular weight of 10,
If it is less than 000, the mechanical strength of the resin is significantly reduced,
Not practical. On the other hand, if it is 300,000 or more, the viscosity of the coating solution becomes high, and it is difficult to apply the cast film to an appropriate film thickness to produce it. The wax used in the present invention has an ester group and may be any one having an ester group in the molecule, and preferably has at least one carbon atom of a carboxylic acid or alcohol as a raw material component of the wax. It is a wax of 12 or more and 40 or less. The larger the carbon number, the higher the melting point and the better the mechanical properties. On the other hand, if the carbon number is too large, it is likely to precipitate in the coating solution, so the carbon number in the above range is preferable.

In order to improve the compatibility of the wax in the photosensitive layer, a wax having two or more ester groups is preferable. As such a wax, a wax having two or more ester groups obtained by a condensation reaction from a dialcohol (or polyalcohol), a dicarboxylic acid (or polycarboxylic acid), and a monocarboxylic acid or monoalcohol is preferable. In this case, at least one of the raw materials preferably has 12 to 40 carbon atoms, and the other raw materials preferably have 40 or less carbon atoms. More preferably, a wax having an endothermic peak in the range of 40 to 130 ° C. in the DSC measurement of the wax is preferred. As a specific example of the wax, one having one ester group

[0020]

Embedded image R ¹ —COO—R ²

(Wherein, R ¹ and R ² are hydrocarbon groups having 1 or more carbon atoms, and are aliphatic hydrocarbon groups (which may be linear or branched, saturated or unsaturated), Represents an aromatic hydrocarbon group or an alicyclic hydrocarbon group.) Of these, R ¹ has 11 to 39 carbon atoms and R ²
Is preferably a linear saturated aliphatic hydrocarbon group having 12 to 40 carbon atoms. Examples of such a wax include cetyl palmitate, stearyl stearate, behenyl behenylate, cetyl myristate, and palmitic hexadecylate. Examples of waxes having two or more ester groups include pentaerythritol stearic acid tetraester, pentaerythritol behenic acid tetraester, pentaerythritol behenic acid diester, pentaerythritol behenic acid triester, and neopentyl glycol bee Examples include diesters of henic acid, condensates of nonanediol, sebacic acid and stearyl alcohol, and condensates of decanediol, azelaic acid and stearyl alcohol.

If the amount of the wax is too small, there is no effect on the mechanical properties.
It adversely affects properties such as the smoothness of the coating film surface. Therefore,
The addition amount is preferably in the range of 0.01% to 30%, more preferably 0.1% to 10%, based on the total solid weight of the surface layer. It is also possible to use two or more different waxes, and in this case, there is an effect of suppressing the deposition of the wax after application and drying.

The effect of using the above specific polycarbonate resin and wax in combination is that the presence of an aliphatic ester group in the side chain of the polycarbonate resin improves the compatibility of the wax, especially the ester wax, with the resin. It is mentioned. This allows the wax to be more uniformly present in the photosensitive layer and allows for the addition of higher parts by weight. This improves slipperiness, improves light transmittance by improving compatibility,
And the effect of preventing the deterioration of the electric characteristics is observed. Among them, regarding the slipperiness, when the polycarbonate resin is used alone or when the wax is used for the polycarbonate resin having no ester group in the side chain, the synergistic effect on the improvement of the slipperiness is more than the addition of the respective effects. The effect is often observed.

Next, the structure of the electrophotographic photosensitive member according to the present invention will be described. In the present invention, the photosensitive layer is provided on a conductive support. Examples of the conductive support include a metal material such as aluminum, aluminum alloy, stainless steel, copper, and nickel, a metal, carbon, and a resin material to which conductivity is added by adding a conductive powder such as tin oxide, aluminum, or the like. Resins, glass, paper, and the like, in which a conductive material such as nickel or ITO (indium oxide-tin oxide) is deposited or applied on the surface thereof, are mainly used. As a form, a drum shape, a sheet shape, a belt shape, or the like is used. A conductive material having an appropriate resistance value may be applied on a conductive support made of a metal material for controlling conductivity and surface properties and for covering defects.

When a metal material such as an aluminum alloy is used as the conductive support, it may be used after subjecting it to an anodic oxidation treatment, a chemical conversion treatment and the like. When the anodic oxidation treatment is performed, it is preferable to perform a known method, for example, a sealing treatment such as a treatment with a sealing agent such as nickel acetate. The surface of the support may be smooth, or may be roughened by using a special cutting method or performing a polishing treatment. Further, the support may be roughened by mixing particles having an appropriate particle diameter with the material constituting the support. An undercoat layer may be provided between the conductive support and the photosensitive layer in order to improve adhesion and blocking properties.
As the undercoat layer, a resin, a resin in which particles of a metal oxide or the like are dispersed, or the like is used.

Examples of the metal oxide particles used for the undercoat layer include metal oxide particles containing one kind of metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, and the like. Examples include metal oxide particles containing a plurality of metal elements such as calcium, strontium titanate, and barium titanate. One type of particles may be used alone, or a plurality of types of particles may be mixed and used. Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic substance such as stearic acid, polyol, or silicone. As the crystal form of the titanium oxide particles, any of rutile, anatase, Brookite, and amorphous can be used. A plurality of crystals may be included.

As the particle size of the metal oxide particles used for the undercoat layer, various types can be used. Among them, from the viewpoint of the characteristics and the stability of the liquid, the average primary particle size is 10 n.
m or more and 100 nm or less, and particularly preferably,
10 nm or more and 25 nm or less. The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. As the binder resin used for the undercoat layer, phenoxy, epoxy, polyvinylpyrrolidone, polyvinyl alcohol, casein, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide and the like alone or in a form cured together with a curing agent. Among them, alcohol-soluble copolymerized polyamide, modified polyamide and the like are preferable because they exhibit good dispersibility and coating properties.

Although the addition ratio of the inorganic particles to the binder resin can be arbitrarily selected, it is preferable to use the resin in the range of 10 to 500 parts by weight for the stability of the dispersion and the coating property. Is preferred. The thickness of the undercoat layer can be arbitrarily selected, but is preferably 0.1 μm to 20 μm from the characteristics of the photoreceptor and the applicability. A known antioxidant may be added to the undercoat layer. As a specific configuration of the photosensitive layer of the present invention, a charge-generating layer having a charge-generating substance as a main component, a charge-transporting layer having a charge-transporting substance and a binder-resin as a main component are laminated in this order, An inverted double-layer type photoreceptor in which a charge transporting layer mainly composed of a charge transporting substance and a binder resin and a charge generating layer mainly containing a charge generating substance are laminated in this order; and containing a charge transporting substance and a binder resin. And a dispersion type photoconductor in which a charge generating substance is dispersed in a layer to be formed.

In the case of a laminated photoreceptor, examples of the charge generating material used in the charge generating layer include selenium and its alloys, cadmium sulfide, other inorganic photoconductive materials, phthalocyanine pigments, azo pigments, quinacridone pigments, and indigo pigments. And various photoconductive materials such as organic pigments such as perylene pigments, polycyclic quinone pigments, anthantrone pigments and benzimidazole pigments, and especially organic pigments, among which phthalocyanine pigments and azo pigments are preferred. The charge generation layer can be formed by vapor deposition, but fine particles of these materials can be formed by, for example, polyester resin, polyvinyl acetate, polyacrylate, polymethacrylate, polyester, polycarbonate, polyvinyl acetoacetal, polyvinyl propional, and polyvinyl butyral. It is preferably used in a form bound with various binder resins such as phenoxy resin, epoxy resin, urethane resin, cellulose ester and cellulose ether. The use ratio in this case is used from the range of 30 to 500 parts by weight with respect to 100 parts by weight of the binder resin,
The film thickness is usually from 0.05 μm to 3 μm, preferably from 0.1 μm to 1 μm, particularly preferably from 0.15 μm to 0.6 μm.

When a phthalocyanine compound is used as the charge generating substance, specifically, a metal-free phthalocyanine,
Metals such as copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, and germanium, or coordinated phthalocyanines such as oxides and halides thereof are used. Examples of the ligand to a trivalent or higher valent metal atom include a hydroxyl group and an alkoxy group in addition to the above-described oxygen atom and chlorine atom. Especially sensitive, X-type, τ
Preferred are metal-free phthalocyanines of the type, titanyl phthalocyanines such as α-type, β-type and Y-type, vanadyl phthalocyanine, chloroindium phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine and the like. In addition, among the crystal forms of titanyl phthalocyanine mentioned here, β-form and α-form are described in W.C. These are shown as Phase I and Phase II by Heller et al. (Zeit. K
ristallogr. 159 (1982) 173), β-form is known as a stable form. The Y type is characterized in that, in powder X-ray diffraction using CuKα rays described in Japanese Patent Publication No. Hei 7-91486, a diffraction angle 2θ ± 0.2 ° shows a clear peak at 27.3 °. Is a crystal type. The phthalocyanine compound may be a single compound alone, or may be a mixture of several compounds. As the phthalocyanine compound or a mixed state that can be placed in a crystalline state here, the respective components may be mixed and used later, or the mixed state may be used in a phthalocyanine compound production / treatment step such as synthesis, pigmentation, and crystallization. It may be the one that has occurred. As such a treatment, an acid paste treatment, a grinding treatment, a solvent treatment and the like are known.

Examples of the charge transport material contained in the charge transport layer include aromatic nitro compounds such as 2,4,7-trinitrofluorenone, carbazole derivatives, indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, and oxadiazole. Derivatives, pyrazoline derivatives, heterocyclic compounds such as thiadiazole derivatives, aniline derivatives, hydrazone compounds, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine compounds,
Examples thereof include those in which a plurality of these compounds are bonded, and electron-donating substances such as polymers having a group consisting of these compounds in the main chain or side chain. The charge transporting materials may be used alone or in combination. The charge transport layer is formed in a state where these charge transport materials are bound to the binder resin. The charge transport layer may be composed of a single layer, or may be a laminate of a plurality of layers having different constituent components or composition ratios.

The ratio between the binder resin and the charge transport material is as follows:
Usually, 30 to 20 parts by weight per 100 parts by weight of the binder resin.
0 parts by weight, preferably in the range of 40 to 150 parts by weight. The thickness is generally 5 to 50 μm, preferably 1 to 50 μm.
It is preferably from 0 to 45 μm. The charge transport layer has a well-known plasticizer, an antioxidant, an ultraviolet absorber, and an electron-attracting property in order to improve film formability, flexibility, coating properties, stain resistance, gas resistance, light resistance, and the like. Additives such as compounds and leveling agents may be included. Examples of the antioxidant include a hindered phenol compound and a hindered amine compound. In the case of the dispersion type, it is preferable that the charge generation material is used in the range of 1 to 50 parts by weight and the charge transporting material is used in the range of 30 to 150 parts by weight based on 100 parts by weight of the binder resin. The film thickness is usually 5 to 50 μm, preferably 10 to 3 μm.
0 μm is preferred. Further, if necessary, various additives such as an antioxidant and a sensitizer may be contained. In the case of the dispersion type photosensitive layer, in the charge transport medium having the above-described compounding ratio,
The charge generation material described above is dispersed.

In this case, it is necessary that the particle size of the charge generating substance is sufficiently small, and it is preferably 1 μm or less, more preferably 0.5 μm or less. If the amount of the charge generating substance dispersed in the photosensitive layer is too small, sufficient sensitivity cannot be obtained. If the amount is too large, there are adverse effects such as a decrease in chargeability and a decrease in sensitivity. %, More preferably in the range of 1 to 20% by weight. The thickness of the photosensitive layer is usually 5 to 50 μm, more preferably 10 to 45 μm. Also in this case, a well-known plasticizer for improving film formability, flexibility, mechanical strength, etc., an additive for suppressing residual potential, a dispersion auxiliary for improving dispersion stability, a coating property. Leveling agents and surfactants, such as silicone oil, fluorine-based oils, and other additives, may be added to improve the viscosity.

A protective layer may be provided on the photosensitive layer for the purpose of preventing the photosensitive layer from being worn and preventing or reducing the deterioration of the photosensitive layer due to a discharge product or the like generated from a charger or the like. Also, in order to reduce the frictional resistance and wear of the photoconductor surface,
The surface layer may contain a fluorine resin, a silicone resin or the like in addition to the wax. Further, particles of these resins or particles of an inorganic compound may be included. Each layer constituting these photoreceptors, dip coating, spray coating, nozzle coating, bar coating, roll coating,
It is formed by coating by blade coating or the like. As a method for forming each layer, a known method such as sequentially applying a coating solution obtained by dissolving or dispersing a substance to be contained in a layer in a solvent can be applied.

An electrophotographic apparatus such as a copying machine or a printer using the electrophotographic photoreceptor of the present invention includes at least each of charging, exposing, developing, and transferring processes. May be. As a charging method (charging device), for example, any of corotron or scorotron charging using corona discharge, contact charging using a conductive roller, a brush, a film, or the like may be used. Among them, in the charging method using corona discharge, scorotron charging is often used in order to keep the dark area potential constant. As a developing method, a general method of developing by contacting or non-contacting a magnetic or non-magnetic one-component developer, a two-component developer or the like is used.
As a transfer method, any of a method using corona discharge, a method using a transfer roller or a transfer belt, and the like may be used.
The transfer may be performed directly on paper, OHP film, or the like, or temporarily performed on an intermediate transfer body (belt or drum).
After the transfer, the image may be transferred onto paper or an OHP film. Usually, after the transfer, a fixing process of fixing the developer onto paper or the like is used, and as a fixing unit, generally used heat fixing, pressure fixing, or the like can be used.
In addition to these processes, a process such as cleaning and static elimination that is usually used may be provided.

[0036]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the invention. In the examples, "part"
Represents "parts by weight". Example 1 [Production of photoreceptor] 10 parts by weight of β-type oxytitanium phthalocyanine was added to 150 parts by weight of 4-methoxy-4-methyl-2-pentanone, and pulverized and dispersed by a sand grinding mill. Further, polyvinyl butyral (Denka Butyral # 6, manufactured by Denki Kagaku Kogyo KK)
000C) in 5% 1,2-dimethoxyethane solution 10
0 parts and 100 parts of a 5% 1,2-dimethoxyethane solution of a phenoxy resin (trade name: PKHH, manufactured by Union Carbide Co., Ltd.) were mixed to prepare a binder solution. The binder solution 10 was added to 160 parts by weight of the previously prepared pigment dispersion.
0 parts by weight and an appropriate amount of 1,2-dimethoxyethane were added to finally prepare a dispersion having a solid content of 4.0%. The thus obtained dispersion was applied on a polyethylene terephthalate film on which aluminum was vapor-deposited on the surface so as to have a film thickness of 0.2 μm, thereby providing a charge generation layer. Next, on this film, 70 parts of the following hole transporting compound [1]

[0037]

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2 parts of the following wax (W-1):

[0039]

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2 parts of the following wax (W-1):

[0041]

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And 100 parts of a polycarbonate resin having a viscosity average molecular weight of 34,000 represented by the following structural formula [A]:

[0043]

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A solution prepared by dissolving 0.03 part of silicone oil in a mixed solvent of toluene and tetrahydrofuran as a leveling agent is applied, and dried at 125 ° C. for 20 minutes, and charge transported so that the film thickness after drying is 20 μm. Layers were provided.

[Friction test] The toner is uniformly placed on the photoreceptor prepared above at a concentration of 0.1 mg / cm ^2, and the surface to be brought into contact with the photoreceptor has a thickness of 2 m made of the same material as the cleaning blade.
45 cm of urethane rubber cut into 1 cm width
Used at an angle of degree, load 200g, speed 5mm / sec,
The dynamic friction coefficient was measured using a fully automatic friction and wear tester DFPM-SS manufactured by Kyowa Interface Chemical Co., Ltd. under the conditions of a stroke of 20 mm and a repetition of 100 times. Table 1 shows the results.

[Electrical Characteristics] A photoreceptor measuring machine (Model EPA-8100, manufactured by Kawaguchi Electric Co., Ltd.)
And the current flowing into the aluminum surface is 50μA
Exposure and static elimination are performed after the charge, and the half-exposure amount (E _1/2 , unit μJ / cm ² , reference potential: -4)
50 V) and the residual potential (Vr, unit V) were measured. Table 1 shows the results.

Example 2 The same as Example 1 except that 4 parts of wax (W-1) were used instead of 2 parts of wax (W-1) and 2 parts of wax (W-2) in Example 1 above. A photoreceptor was manufactured and the coefficient of friction and electrical characteristics were measured. Table 1 shows the results. Example 3 Except that 2 parts of wax (W-1) and 2 parts of wax (W-2) were used instead of 2 parts of wax (W-1) and 2 parts of wax (W-2) in Example 1. Manufactured a photoreceptor in the same manner as in Example 1, and measured the coefficient of friction and the electrical characteristics. Table 1 shows the results.

Comparative Example 1 Instead of the polycarbonate resin represented by the structural formula [A] used in the above-mentioned Example 1, represented by the following structural formula [B], m / n = 50/50 (molar ratio) A photosensitive member was manufactured in the same manner as in Example 1 except that a polycarbonate resin having a viscosity average molecular weight of 33,000 was used, and the friction coefficient and the electrical characteristics were measured. Table 1 shows the results.

[0049]

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Comparative Example 2 In place of the polycarbonate resin represented by Structural Formula [A] used in Example 1 above, represented by the above Formula [B], m / n = 50/50 (molar ratio) A photosensitive member was manufactured in the same manner as in Example 1, except that a polycarbonate resin having a viscosity average molecular weight of 33,000 was used, and the wax (W-1) and the wax (W-2) were omitted. It was measured. Table 1 shows the results.

Comparative Example 3 A photoconductor was prepared in the same manner as in Example 1, except that the wax (W-1) and the wax (W-2) used in Example 1 were omitted, and the friction coefficient and the electrical characteristics were measured. It was measured.
Table 1 shows the results.

[0052]

[Table 1]

Example 4 A charge-generating layer was prepared using a Y-type oxytitanium phthalocyanine in place of the β-type oxytitanium phthalocyanine used in the above-mentioned Example 1, and a polycarbonate represented by the structural formula [A] was prepared. In place of resin, represented by the following structural formula [C], m / n / l = 27/63/10
(Molar ratio), a polycarbonate resin having a viscosity average molecular weight of 49,000, and a hole transport compound [2] having the following structural formula, instead of 70 parts of the hole transport compound [1], were used, and the same procedure was carried out. A photoreceptor was manufactured in the same manner as in Example 1, and the coefficient of friction and the electrical characteristics were measured. Table 2 shows the results.

[0054]

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Comparative Example 4 In place of the polycarbonate resin represented by the structural formula [C] used in Example 4, the resin was represented by the following structural formula [D], and m / n = 30/70 (molar ratio) A photoconductor was manufactured in the same manner as in Example 4 except that a polycarbonate resin having a viscosity average molecular weight of 24,100 was used, and the friction coefficient and the electrical characteristics were measured. Table 2 shows the results.

[0056]

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Comparative Example 5 In place of the polycarbonate resin represented by the structural formula [C] used in Example 4, the resin was represented by the structural formula [D], and m / n = 30/70 (molar ratio). A photoconductor was prepared in the same manner as in Example 4, except that a wax resin (W-1) and a wax (W-2) were used, and that the friction coefficient and the electrical characteristics were changed. It was measured. Table 2 shows the results. Comparative Example 6 A photoconductor was prepared in the same manner as in Example 4, except that the wax (W-1) and the wax (W-2) used in Example 4 were omitted, and the friction coefficient and the electrical characteristics were measured.
Table 2 shows the results.

[0058]

[Table 2]

[0059]

According to the present invention, it is possible to significantly improve the slipperiness and slidability of the surface of the electrophotographic photosensitive member without adversely affecting the electrical characteristics. It is extremely effective for prolonging the life of the photoconductor, and is useful for high-speed copying machines, power-saving copying machines, printers, and the like.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shinichi Suzuki 1000 Kamoshita-cho, Aoba-ku, Yokohama-shi, Kanagawa Prefecture Mitsubishi Chemical Corporation Yokohama Research Laboratory F-term (reference) 2H068 AA03 AA06 AA13 AA14 AA21 BB26 BB64 FA04 FA05

Claims (3)

[Claims] 1. An electrophotographic photosensitive member having at least a photosensitive layer on a conductive substrate, wherein the photosensitive layer comprises a charge generating substance,
A charge transport substance, a polycarbonate resin and a wax having an ester group, and wherein the polycarbonate resin is substituted with a monovalent organic residue containing an ester of an aliphatic alcohol having 4 or more carbon atoms and a carboxylic acid having 1 or more carbon atoms. An electrophotographic photoreceptor, characterized in that said electrophotographic photoreceptor contains bisphenol as a constituent. 2. The electrophotographic photosensitive member according to claim 1, wherein at least one of a carboxylic acid and an alcohol which is a raw material component of the wax having an ester group has 12 or more carbon atoms. 3. The electrophotographic photoreceptor according to claim 1, wherein the wax is a wax having two or more ester groups.