JPH02240656A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To ensure both high surface hardness and good surface lubricity by incorporating at least one kind of polycarbonate-polysiloxane block copolymers composed of specified structural units and at least one kind of fluoropolycarbonate resins composed of specified structural units. CONSTITUTION:The polycarbonate-polysiloxane block copolymers is composed of the structural units represented by formula I in which each of R1 - R8 is H, halogen, or the like; each of R9 and R10 is optionally substituted alkyl or aryl; A is a group represented by formula III in which each of Ra and Rb is H, optionally substituted alkyl or the like; and each of Rc and Rd is optionally substituted alkyl or the like. This copolymer is used in combination with the fluoropolycarbonate resin represented by formula II in which each of R11 - R18 is H or lower alkyl; and each of R19 and R20 is H or the like, thus permitting surface hardness and surface lubricity to be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor using a polycarbonate-polysiloxane block copolymer as a binder resin.

BACKGROUND OF THE INVENTION In recent years, electrophotographic technology has been widely applied in fields such as copying machines and laser beam printers because it has the advantage of being able to achieve high speed and high print quality.

As electrophotographic photoreceptors used in these electrophotographic techniques, those using inorganic photoconductive materials such as selenium, selenium-tellurium alloy, selenium-arsenic alloy, and cadmium sulfide are widely known. On the other hand, research on electrophotographic photoreceptors using organic photoconductive materials, which have advantages over electrophotographic photoreceptors using inorganic photoconductive materials in terms of cost and ease of manufacture and disposal, has become active. For example, as disclosed in JP-A-61-132954N, electrophotographic photoreceptors using a polycarbonate-polysiloxane block copolymer as a binder resin for a charge generation layer or a charge transport layer have been developed. Are known.

Problems to be Solved by the Invention However, electrophotographic photoreceptors using the polycarbonate-polysiloxane block copolymer as a binder resin for a charge generation layer or a charge transport layer have poor electrical properties such as sensitivity and chargeability. Although it shows good performance, there are problems with durability against mechanical external forces, that is, image defects occur due to abrasion or scratches on the surface of the photoreceptor due to direct stress from toner, developer, paper, cleaning members, etc., or Low-resistance substances such as ozone and nitrogen oxides generated by corona discharge and paper dust generated from copy paper adhere to and accumulate on the surface of the photoreceptor, causing problems such as image smearing in high-humidity environments. It limits body lifespan.

Various measures have been considered to solve these problems, and the first one is to increase the hardness of the photoreceptor surface, thereby suppressing the occurrence of wear and scratches.
Second, it increases the lubricity of the surface of the photoreceptor, thereby suppressing wear, and improves the releasability of the adhering accumulation from the surface of the photoreceptor, thereby preventing the occurrence of image deletion. However, the current situation is that satisfactory performance has not yet been achieved. Therefore, it has been desired to develop a binder resin that can form a photosensitive layer having high surface hardness and good surface lubricity.

The present invention was made as a result of the above-mentioned circumstances and aims to solve the above-mentioned problems in the conventional technology.

That is, an object of the present invention is to provide an electrophotographic photoreceptor having a photosensitive layer having both high surface hardness and good surface lubricity.

Means and Effects for Solving the Problems As a result of various studies on the binder resin of the photosensitive layer, the inventors of the present invention have developed a polycarbonate-polysiloxane block copolymer consisting of the structural unit shown in (1) below. By using a combination of the fluorine-containing polycarbonate resin shown below and below (II>), extremely superior surface hardness and surface lubrication can be achieved compared to when the above polycarbonate-polysiloxane!] ivy copolymer is used alone. It simultaneously eliminates the above-mentioned problems, namely, image quality defects due to abrasion and scratches on the surface of the photosensitive layer, and image deletion due to adhesion and accumulation of paper dust, and dramatically improves the lifespan of electrophotographic photoreceptors. bring forth what can be done,
The present invention has now been completed.

The present invention provides an electrophotographic photoreceptor comprising a photosensitive layer provided on a conductive substrate, in which the photosensitive layer contains the following -
One or more polycarbonate-polysiloxane block copolymers consisting of structural units represented by <1)
In the above C formula, R1, R2, R3, R4, R5, R5, R7 and R8 each represent a hydrogen atom, a halogen atom or a lower alkyl group, and R9 and Rho each may have a substituent. Represents an alkyl group or an aryl group, A
is -CO--〇-1 or -(CH2)n (where 0 represents an integer of 2 or more, and Ra and Rb each represent a hydrogen atom, an alkyl group or an aryl group that may have a substituent) or Ra
and R1) represent a group that is bonded together to form a carbocyclic or heterocyclic ring, and RC and R each represent an alkyl group or an aryl group that may have a substituent), 9
and rn represents (Ω/(,Q0m)=0.1 to 0.9). ] and one or more polycarbonate resins consisting of structural units represented by the following general formula (n) (in the formula, Ro, RI2, RI3・RI4・R15・R16, R
17 and R+g are each a hydrogen atom, a halogen atom,
Represents an alkyl group or an aryl group, RI9 and R20
each represents a hydrogen atom, a fluorine atom, an alkyl group or an aryl group which may have a substituent, or R1
9 and R20 represent a group that is bonded together to form a carbocyclic ring. However, at least one of R11 to R20 represents a fluorine atom or a fluorine atom-substituted alkyl or aryl group. ) is characterized by containing.

The present invention will be explained in detail below.

The conductive substrate in the electrophotographic photoreceptor of the present invention includes:
Conductive substances such as aluminum, nickel, chromium, titanium, palladium, indium oxide, tin oxide, graphite, etc. are deposited on metal plates such as aluminum, brass, copper, nickel, and steel, metal sheets, and plastic sheets.
It is possible to use materials that have been subjected to conductive treatment by coating by sputtering, coating, etc., or materials that have been subjected to conductive treatment such as glass, plastic plates, cloth, and paper.

A photosensitive layer of a dispersed type, a laminated type, etc. is provided on the conductive substrate, and an undercoat layer having a barrier function or adhesive function is optionally provided between the photosensitive layer and the conductive substrate. It may be provided. As materials constituting the undercoat layer, resins such as polyvinyl butyral, polyvinyl alcohol, casein, polyamide, cellulose, gelatin, polyurethane, and Bossester, and metal oxides such as aluminum oxide can be used.

The photosensitive layer formed on the conductive substrate may have a single layer structure or may have a laminated structure in which a charge generation layer and a charge transport layer are functionally separated. In the case of a laminated structure, the charge generation layer and the charge transport layer may be stacked in any order.

These photosensitive layers are composed of a coating film containing a charge generating substance, a charge transporting substance, or both in a binder resin.

As charge generating substances, amorphous selenium, crystalline selenium,
Selenium-tellurium alloy, selenium-arsenic alloy, other selenium compounds and alloys, inorganic photoconductors such as zinc oxide and titanium oxide, phthalocyanine type, square Cum type, anthanthrone type, perylene type, azo type, anthracene type , pyrene, pyrylium salts, thiapyrylium salts, and other organic pigments and dyes are used.

Charge transport substances include benzoquinone, chloranil,
Quinone compounds such as bromoanil and anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-dolinitrofluorenone, 2,4,5,7-titranitrofluorenone, and fluorenone-9-
Electron-withdrawing substances such as malononitrile compounds, xanthone compounds, benzophenone compounds, cyanvinyl compounds, ethylene compounds, pyrazoline compounds, hydrazone compounds, oxazole compounds, carbazole compounds, arylalkane compounds, triphenyl An electron-donating substance such as an amine compound, an aryl-substituted ethylene compound, a benzidine compound, a stilbene compound, an anthracene compound, or a polymer having a group consisting of these compounds in its main chain or side chain is used.

Among these, it is particularly preferable to use the triphenylamine compounds shown in the following formula (1).

(In the formula, R21 and R22 are respectively) -1 or CH
3, R23 is H1CH3, C2to15 or C1
) In the present invention, as the binder resin, the above-mentioned clothing material (I)
A polycarbonate polysiloxane block copolymer consisting of the structural unit represented by the formula (H) and a fluorine-containing polycarbonate resin represented by the general formula (H) are used together. When the photosensitive layer has a laminated structure in which a charge generation layer and a charge transport layer are functionally separated, both of the above resins can be used as a binder resin for either the charge generation layer or the charge transport layer. , it is desirable to use it at least in a layer forming the surface. In particular, it is preferable to use it together with a binder resin when the surface is composed of a charge transport layer.

The polycarbonate-polysiloxane block copolymer consisting of the structural unit represented by the above-mentioned -clothing cost (I) used in the present invention has an average molecular weight of 10,000 to 300,000, particularly 2
It is preferably in the range of 20,000 to 200,000.

Specific examples of the polycarbonate-polysiloxane block copolymer represented by the general formula (I) that can be suitably used in the present invention include those having the following structural units as constituent components.

(j/(o+w)-0.1 to 0.9) In the present invention, known fluorine-containing polycarbonate resins consisting of the structural unit represented by the above-mentioned -clothing cost (n) are used. Usually, those having an average molecular weight in the range of 20,000 to 200,000 are used.

Specifically, for example, those having the following structural units as constituent components are exemplified.

(j / (j 10m) 閤o, i~0.9) (2〆(1
+■) -0.1 to 0.9) In the present invention, the polycarbonate-polysiloxane block copolymer represented by the above-mentioned - clothing cost (I) and the fluorine-containing polycarbonate resin represented by the above-mentioned - clothing cost (II); The content ratio of the former can be set arbitrarily, but the former:
It is preferable to use the latter at a content ratio in the range of 90:1 to 5:95.

In the present invention, when the photosensitive layer has a laminated structure, the charge generation layer is formed by applying a coating solution obtained by dispersing or dissolving the above charge generation substance and binder resin in a suitable solvent, and drying. can be formed. As the binder resin, known ones such as polystyrene, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer,
Conventionally known thermoplastic resins such as polyvinyl acetal, alkyd resin, acrylic resin, polyacrylonitrile, polycarbonate, polyamide, polyketone, polyacrylamide, butyral resin, polyester, thermosetting resin such as polyurethane, epoxy resin, phenol resin, etc. things can be used.

The thickness of the charge generation layer is usually set to 0.05 to 40, preferably 0.05 to 25JIr1.

Further, the charge transport layer can be formed by applying a solution in which the above charge transport substance, the above polycarbonate-polysiloxane block copolymer and the fluorine-containing polycarbonate resin are dissolved in an appropriate solvent, and drying the solution. . Many useful organic solvents can be used as the solvent used to form the charge transport layer. Typical examples include aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene, ketones such as acetone and 2-butanone, and halogenated aliphatic carbons such as methylene chloride, chloroform, and ethylene chloride. Examples include hydrogens, cyclic or straight ethers such as tetrahydrofuran, dioxane, ethylene glycol, and diethyl ether, and mixtures thereof.

The thickness of the charge transport layer is 2 to 100 mm, preferably 10 to 100 mm.
It is set to 40m.

Example Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 An aluminum pipe was used as a conductive substrate, and a coating solution consisting of 10 parts by weight of alcohol-soluble polyamide resin, 150 parts by weight of methanol, and 40 parts by weight of water was applied onto the pipe by dip coating, and dried to form a film with a thickness of 1 μm. A subbing layer was formed.

Next, granular trigonal selenium (manufactured by Zero Rafusfu Co., Ltd., USA) 9
0 parts by weight, 10 parts by weight of modified polyvinyl butyral resin,
A mixture consisting of 300 parts by weight of n-butanol was dispersed, and 1 part by weight of the resulting dispersion was diluted with 2 parts by weight of n-butanol, and the solution was applied onto the above-mentioned undercoat layer by dip coating. , and was dried to form a charge generation layer having a thickness of 0.2IIM.

Then N,N"-diphenyl-N,N'-bis(3-methylphenyl)-E1,1'-biphenyl]-4,4
3 parts by weight of '-diamine and a polycarbonate-polysiloxane block copolymer (PS099, Petrarch Systems) represented by the following structural formula (Ni1')
Co., Ltd. > 3ff and 1 part of fluorine-containing polycarbonate resin (average molecular weight approximately 30,000) type 7 made of structural units represented by the following structural formula ([-1>), 2 parts each of tetrahydrofuran and 134-dioxane, and 1 part each of tetrahydrofuran and 134-dioxane. The resulting solution was applied by dip coating onto the above charge generation layer and dried to form a charge transport layer with a thickness of 20 pm. The body was created.

1! / (N + m) = 0.50 The electrophotographic photoreceptor produced as described above was installed in a copying machine equipped with a blade cleaning member, and 50,000
We investigated the occurrence of image defects due to abrasion and scratches on the surface of the electrophotographic photoreceptor, the amount of surface abrasion, and the occurrence of image deletion under high temperature and high humidity environments when copying sheets. Examined pencil hardness. Results first
Shown in the table.

Example 2 In Example 1, as the binder resin of the charge transport layer, 5 parts by weight of a polycarbonate-polysiloxane block copolymer consisting of the structural unit represented by the structural formula (I-1') and the structural formula (n An electrophotographic photoreceptor was prepared in the same manner as in Example 1 above, except that a mixture with a fluorine-containing polycarbonate resin consisting of the structural unit represented by -1> was used, and evaluation was conducted in the same manner. The results are shown in Table 1.

Example 3 In Example 1, as the binder resin of the charge transport layer, 3 parts by weight of a polycarbonate-polysiloxane block copolymer consisting of the structural unit represented by the structural formula (I-1') and the following structural formula (II-1') were used. -2> Fluorine-containing polycarbonate resin (average molecular weight approximately 30,000)
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 above, except that a mixture with 7 parts by weight was used, and evaluation was performed in the same manner. The results are shown in Table 1.

Example 4 In Example 3, as the binder resin of the charge transport layer, 5 parts by weight of a polycarbonate polysiloxy→nanblock copolymer consisting of the structural unit represented by the structural formula (I-1') and the structural formula An electrophotographic photoreceptor was prepared in the same manner as in Example 1 above, except that a mixture with 5 parts of a fluorine-containing polycarbonate resin consisting of the structural unit represented by (n-2) was used. We conducted an evaluation. The results are shown in Table 1.

Comparative Example As the binder resin of the charge transport layer, the above structural formula (knee 1')
Electrophotographic photoreceptors were prepared in the same manner as in Example 1, except that 10 parts by weight of only the polycarbonate-bolysiloxy-4 non-block copolymer represented by the formula were used, and evaluations were made in the same manner. The results are shown in Table 1.

Table 1 Effects of the Invention In the present invention, as the binder resin of the photosensitive layer, a polycarbonate-polysiloxane block copolymer consisting of the structural unit represented by the above-mentioned (1) and the above-mentioned (n
), the electrophotographic photoreceptor of the present invention has extremely excellent surface hardness and surface lubricity. It has excellent durability, suppresses the occurrence of image defects due to abrasion and scratches on the surface of the photosensitive layer, and at the same time eliminates the occurrence of image deletion due to adhesion and accumulation of paper dust, and dramatically improves the service life.

Patent applicant Fuji Xerox Co., Ltd. Agent
Patent Attorney Tsuyoshi Abori

Claims (2)

[Claims] (1) In an electrophotographic photoreceptor comprising a photosensitive layer provided on a conductive substrate, the photosensitive layer is made of a polycarbonate-polysiloxane block copolymer consisting of a structural unit represented by the following general formula (I) as a binder resin. One or more combinations▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [In the formula, R_1, R_2, R_3, R_4, R_5, R
_6, R_7 and R_8 each represent a hydrogen atom, a halogen atom or a lower alkyl group, R_9 and R_1
_0 represents an alkyl group or an aryl group that may each have a substituent, and A has ▲a mathematical formula, a chemical formula, a table, etc.▼, ▲a mathematical formula, a chemical formula,
There are tables, etc.▼, -S-, -SO_2-, -CO-, -O-, or -(CH_2)_n- (however,
n represents an integer of 2 or more, and R_a and R_b each represent a hydrogen atom, an alkyl group or an aryl group which may have a substituent, or R_a and R_b are bonded together to form a carbocyclic or heterocyclic ring. (R_c and R_d each represent an alkyl group or an aryl group which may have a substituent), l and m are (l/(l+m)=0.1 to 0.9)
represents. ) and one or more fluorine-containing polycarbonate resins consisting of structural units represented by the following general formula (II) ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (II) (In the formula, R_1_1, R_1_2, R_1_3, R_1
_4, R_1_5, R_1_6, R_1_7 and R_1
_8 each represents a hydrogen atom, a halogen atom, an alkyl group, or an aryl group, and R_1_9 and R_2_0 each represent a hydrogen atom, a fluorine atom, an alkyl group or an aryl group that may have a substituent, or R_1
_9 and R_2_0 represent a group that is bonded together to form a carbocyclic ring. However, at least one of R_1_1_ to R_2_0 represents a fluorine atom or a fluorine atom-substituted alkyl or aryl group. ) An electrophotographic photoreceptor comprising: (2) The content ratio of the polycarbonate-polysiloxane block copolymer made of the structural units represented by the above general formula (I) and the fluorine-containing polycarbonate resin made of the structural units shown by the above general formula (II) is 90: 10-5
:95, the electrophotographic photoreceptor according to claim 1.