JP2002107968A - Electrophotographic photoreceptor, process cartridge and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor free of buckling of a cleaning blade with good coatability in production process and a good pot life of a coating material, and to provide a process cartridge and an electrophotographic device using the photoreceptor. SOLUTION: The electrophotographic photoreceptor has a surface layer containing PAR (polyarylate) having a constitutional unit of formula (1), PC (polycarbonate) having a constitutional unit of formula (2), a copolymer having constitutional units of formulae (3) and (4) and a powdery fluororesin. The viscosity average molecular weight (Ma) of the PAR is 30,000-105,000, the viscosity average molecular weight (Mc) of the PC is 25,000-55,000 and the inequality Ma>Mc is satisfied. In the formulae, R1-R28 are each H, an alkyl, aryl or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic photoreceptor,
More particularly, the present invention relates to an electrophotographic photoreceptor having a surface layer containing a specific resin, a process cartridge having the electrophotographic photoreceptor, and an electrophotographic apparatus.

[0002]

2. Description of the Related Art An electrophotographic method is disclosed in U.S. Pat.
As shown in the specification of JP-A-91, an electric resistance changes according to the irradiation amount received during image exposure, and a photoconductive material composed of a support coated with an insulating substance is used in a dark place. The basic characteristics required of an electrophotographic photoreceptor using this photoconductive material include (1) being able to be charged to an appropriate potential in a dark place, (2) being small in potential dissipation in a dark place, (3) Quickly dissipating the charge by light irradiation, and the like.

Conventionally, as an electrophotographic photoreceptor, an inorganic electrophotographic photoreceptor having a photosensitive layer containing an inorganic photoconductive compound such as selenium, zinc oxide and cadmium sulfide as a main component has been widely used. However, these are the above (1) to
The condition of (3) is satisfied, but thermal stability, moisture resistance, durability,
Productivity was not always satisfactory.

In order to overcome the drawbacks of inorganic electrophotographic photosensitive members, electrophotographic photosensitive members containing various organic photoconductive compounds as main components have been actively developed in recent years. For example, U.S. Pat. No. 3,838,851 discloses an electrophotographic photoreceptor having a charge transport layer containing triallylpyrazoline, and U.S. Pat. No. 3,871,880 discloses a charge generating layer comprising a derivative of perylene pigment and 3-propylene / formaldehyde. And an electrophotographic photosensitive member comprising a charge transport layer comprising a condensate of the above.

Further, the photosensitive wavelength range of the electrophotographic photosensitive member can be freely selected depending on the organic photoconductive compound.
The substances disclosed in Japanese Unexamined Patent Publication Nos. 72754 and 56-167759 have high sensitivity in the visible region, and are disclosed in Japanese Patent Application Laid-Open Nos. 57-195767 and 61-228453. It is shown that the compound indicated by has sensitivity up to the infrared region. Among these materials, those exhibiting sensitivity in the infrared region include laser beam printers (hereinafter abbreviated as LBPs) and L
Used in ED printers, their demand frequency is increasing.

An electrophotographic photoreceptor using these organic photoconductive compounds is a function-separated type electrophotographic photoreceptor in which a charge transport layer and a charge generation layer are laminated in order to satisfy both electrical and mechanical properties. Often used as. On the other hand, as a matter of course, the electrophotographic photosensitive member is required to have sensitivity, electrical characteristics, and optical characteristics according to the electrophotographic process applied. Particularly, in an electrophotographic photoreceptor that is used repeatedly, an electro-mechanical external force such as corona or direct charging, image exposure, toner development, a transfer process, and surface cleaning is directly applied to the electrophotographic photoreceptor surface. Also, durability for them is required.

More specifically, electrical deterioration due to ozone and nitrogen oxides during charging, discharge during charging, mechanical deterioration in which the surface is worn or scratched due to rubbing of a cleaning member, and electrical deterioration Durability against deterioration is required. The electrical deterioration is particularly problematic in that carriers stay in a portion irradiated with light and a potential difference is generated from a portion not irradiated with light. This occurs as a photo memory. The mechanical deterioration of the organic electrophotographic photoreceptor, which is different from the inorganic electrophotographic photoreceptor in many cases, is often inferior to the mechanical deterioration of the organic electrophotographic photoreceptor, and the improvement of the durability is particularly desired. Various attempts have been made to satisfy the durability characteristics required for the electrophotographic photosensitive member as described above.

As a resin widely used in the surface layer and having good abrasion and electrical properties, a polycarbonate resin having bisphenol A as a skeleton has been attracting attention. However, not all of the above-mentioned problems can be solved, and the following problems cannot be solved. It has the following problems.

(1) It has poor solubility and shows good solubility only in a part of halogenated aliphatic hydrocarbons such as dichloromethane and 1,2-dichloroethane. In addition, since these solvents have a low boiling point, When an electrophotographic photoreceptor is manufactured using a coating solution prepared with the above-mentioned solvent, the coated surface tends to be whitened. It also takes time to control the solid content of the coating liquid.

(2) Solvents other than halogenated aliphatic hydrocarbons are partially soluble in tetrahydrafuran, dioxane, cyclohexanenone or a mixed solvent thereof, but the solution is gelled within a few days. For example, it is not suitable for manufacturing an electrophotographic photoreceptor due to poor aging property.

(3) Further, even if the above (1) and (2) are improved, solvent cracks are liable to occur in the polycarbonate resin having bisphenol A as a skeleton.

(4) In addition, in the conventional polycarbonate resin, the coating formed of the resin has poor lubricity, so that the electrophotographic photosensitive member is easily damaged, and cleaning is performed so as to reduce the abrasion amount of the electrophotographic photosensitive member. The setting may cause an image defect, cleaning failure due to early deterioration of the cleaning blade, toner fusion, and the like.

With respect to the solution stability described in the above (1) and (2), a polycarbonate Z resin having a bulky cyclohexylene group as a polymer structural unit is used or copolymerized with bisphenol Z or bisphenol C or the like. It has been solved by

On the other hand, polyarylate has a structure similar to that of polycarbonate, but differs in various properties. For example, although the mechanical strength is superior, the solubility of bisphenol Z type having a cyclohexyl group is low. Also, there are differences in electrophotographic photoreceptor characteristics, and particularly when used as a binder resin for a charge transport layer, each memory, residual potential, etc. are susceptible to change (deterioration) depending on the structure of the charge transport material used. .

In addition, in a general cleaning method using a rubber blade, which is harder to remove the formed film because it is tougher than the conventional polycarbonate resin, the cleaning blade is not roughened than the polycarbonate and the contact area is increased so that the cleaning blade is applied in the counter direction. When they are in contact with each other, a phenomenon that the cleaning blade is turned up easily occurs.

[0016] Solvent cracks can also be solved by using a silicone-modified polycarbonate or an ether-modified polycarbonate, as disclosed in JP-A-6-51544 and JP-A-6-75415. . However, these modified polycarbonates have a structure that gives flexibility to internal stress in the polymer in order to prevent solvent cracks as compared to conventional polycarbonate resins, so the mechanical strength of the polymer body decreases. Had the disadvantage of doing so.

Further, in recent years, a direct charging system in which a voltage is directly applied to a charging member and a charge is applied to an electrophotographic photosensitive member as disclosed in JP-A-57-17826 and JP-A-58-40566. Is becoming mainstream. this is,
This is a method in which a roller-shaped charging member made of conductive rubber or the like is brought into direct contact with the electrophotographic photoreceptor to apply an electric charge.The amount of ozone generated is significantly smaller than that of a scorotron or the like. About 80% of the charge is wasted because it flows to the shield, whereas direct charging has the advantage of being very economical without this waste.

However, direct charging has a drawback that charging stability is very poor because of charging by discharge according to Paschen's rule. As a countermeasure, a so-called AC / DC charging system in which an AC voltage is superimposed on a DC voltage has been invented (JP-A-63-149668). Although this charging method has improved the stability at the time of charging, the amount of discharge on the surface of the electrophotographic photosensitive member is greatly increased due to the superposition of AC, and the shaving amount of the electrophotographic photosensitive member is increased. A new drawback arises, and not only mechanical strength but also electrical strength is required. Further, it has become necessary to satisfy these requirements without deteriorating electrophotographic properties.

[0019]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problem of having a conventional polycarbonate resin or polyarylate resin as a surface layer, and to achieve high mechanical strength and high lubricity. An object of the present invention is to provide an electrophotographic photosensitive member having both of them consistently after durability, a process cartridge having the electrophotographic photosensitive member, and an electrophotographic apparatus.

Another object of the present invention is to provide an electrophotographic photoreceptor which has good electrophotographic properties, good coating properties at the time of production and paint pot life, and which does not turn over even with a general cleaning blade. An object of the present invention is to provide a process cartridge having the electrophotographic photosensitive member and an electrophotographic apparatus.

[0021]

According to the present invention, in an electrophotographic photosensitive member having a conductive support and a photosensitive layer, the surface layer of the electrophotographic photosensitive member has a structural unit represented by the following formula (1). A polyarylate, a polycarbonate having a structural unit represented by the following formula (2), a copolymer having a structural unit represented by the following formula (3) and the following formula (4), and a fluorine-based resin powder, The viscosity average molecular weight (Ma) of the polyarylate is 30,000 to 105,000, and the viscosity average molecular weight (Mc) of the polycarbonate is 2
An electrophotographic photosensitive member is provided, wherein 5,000 to 55000 and Ma> Mc is satisfied.

[0022]

Embedded image

In the formula, X ¹ represents a carbon atom or a single bond (R ⁵ and R ^{6 in} this case are not present), R ^{1 to} R ⁴ represent a hydrogen atom,
A halogen atom, an alkyl group which may be substituted, an aryl group which may be substituted, and R ⁵ and R ⁶ are a hydrogen atom, a halogen atom, an alkyl group which may be substituted, an aryl group which may be substituted or ⁵ represents an optionally substituted alkylidene group formed by bonding ⁵ and R ⁶ ,
^{7 to} R ¹⁰ represent a hydrogen atom, a halogen atom, an optionally substituted alkyl group, or an optionally substituted aryl group.

[0024]

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[0025] {wherein, X ² represents a carbon atom or a single bond (R ¹⁵ and R ¹⁶ story during this), R ^{1 1} ~R ¹⁴ is a hydrogen atom, a halogen atom, an optionally substituted alkyl group, Represents an aryl group which may be substituted, wherein R ¹⁵ and R ¹⁶ are a hydrogen atom, a halogen atom, an alkyl group which may be substituted, an aryl group which may be substituted, or a group formed by combining R ¹⁵ and R ¹⁶ ; Represents an optionally substituted alkylidene group.

[0026]

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(Wherein, R ^{17 to} R ²² represent a hydrogen atom, a halogen atom, an optionally substituted alkyl group, or an optionally substituted aryl group, and n represents a positive integer)

[0028]

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[0029] {wherein, X ³ represents a carbon atom or a single bond (R ²⁷ and R ²⁸ story during this), R ^{2 3} ~R ²⁶ is a hydrogen atom, a halogen atom, an optionally substituted alkyl group, An aryl group which may be substituted, wherein R ²⁷ and R ²⁸ are a hydrogen atom, a halogen atom, an alkyl group which may be substituted, an aryl group which may be substituted or a group formed by bonding of R ²⁷ and R ²⁸ Represents an optionally substituted alkylidene group.

Further, according to the present invention, there is provided a process cartridge and an electrophotographic apparatus having the above electrophotographic photosensitive member.

The halogen atom in the present invention includes a fluorine atom, a chlorine atom and a bromine atom, the alkyl group includes a methyl group, an ethyl group, a propyl group and a butyl group, and the aryl group includes a phenyl group. And a naphthyl group, and the cycloalkylidene group includes a cyclohexylidene group. Examples of the substituent which the alkyl group, the aryl group and the cycloalkylidene group may have include an alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group, an aryl group such as a phenyl group and a naphthyl group, a fluorine atom, Examples thereof include a halogen atom such as a chlorine atom and a bromine atom. n represents a positive integer and 1
It is preferably from 200 to 200.

[0032]

Embodiments of the present invention will be described below in detail.

Table 1 shows specific examples of the structural unit represented by the formula (1), but the present invention is not limited to these.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

[Table 3]

[0037]

[Table 4]

[0038]

[Table 5]

The polymer having the structural unit represented by the formula (1) used in the present invention is usually used in a mixture of terephthalic acid chloride and isophthalic acid chloride for controlling solubility and rigidity. Interfacial polymerization can be carried out by stirring with various bisphenols in a solvent / water system under an alkali. That is, the formula shown in Table 1 was expressed as a form prepared from a mixed system of terephthalic acid chloride and isophthalic acid chloride. However, the ratio between terephthalic acid chloride and isophthalic acid chloride is determined in consideration of the solubility of the polymer, and there is no established theory. However, it should be noted that if any of the chlorides is 30 mol% or less, the solubility of the synthesized polymer is extremely reduced. Usually, it is preferable to synthesize at a molar ratio of 1/1. In the electrophotographic photoreceptor of the present invention, even if the polymer is constituted by the same structural unit represented by the formula (1), the polymer is composed of two or more different types of structural units represented by the formula (1). It may be united.

Table 2 shows specific examples of the structural unit represented by the formula (2), but the present invention is not limited to these.

[0041]

[Table 6]

[0042]

[Table 7]

[0043]

[Table 8]

[0044]

[Table 9]

Table 3 shows specific examples of the structural unit represented by the formula (3), but the present invention is not limited to these.

[0046]

[Table 10]

[0047]

[Table 11]

[0048]

[Table 12]

Since the expression (4) is the same as the expression (2) shown in Table 2, the example of Table 2 is applied to the example of Expression (4).

Specific examples of the fluororesin powder used in the present invention include ethylene tetrafluoride resin, ethylene trifluoride resin, ethylene tetrafluoride-propylene hexafluoride resin, vinyl fluoride resin, and fluorine fluoride resin. Examples include vinylidene resin, ethylene difluoride ethylene chloride resin, and copolymers thereof. Preferable examples include ethylene tetrafluoride resin and vinylidene fluoride resin, and particularly preferable examples include ethylene tetrafluoride resin.

Although the detailed mechanism has not been fully elucidated, polyarylate having the structural unit represented by the formula (1), polycarbonate having the structural unit represented by the formula (2), and the following formula (3) A copolymer having a structural unit represented by the formula (4), further containing a fluororesin powder,
The viscosity average molecular weight (Ma) of the polyarylate is 3000
0 to 105000; the viscosity average molecular weight (Mc) of the polycarbonate is 25,000 to 55000; and Ma> Mc, whereby the surface lubricity and solvent crack resistance are stably improved from the initial stage to the end of the durability. Can be done.

This is because the polyarylate structure, the polycarbonate structure, and the siloxane structure penetrate into each molecular chain to break the crystallinity of each, and furthermore, the fluororesin powder is dispersed inside the film. Innumerable molecular groups and intramolecular orientational order are created with a fluororesin powder as the core, and by introducing a polyarylate structure with a specific viscosity average molecular weight and a polycarbonate structure with a specific viscosity average molecular weight, Work in a complex way,
It is presumed that this makes it possible to improve high surface lubricity and solvent crack resistance until after durability while maintaining high wear resistance.

This effect is also attributable to the fact that the polyarylate structure, the polycarbonate structure, the siloxane structure, and the fluororesin powder, which are the constituent elements of the present invention, are all present, and the polyarylate structure having a specific viscosity average molecular weight and the specific viscosity average It is effectively expressed when it has a molecular weight polycarbonate structure, and even if one of the constituent elements is missing, the effect is greatly impaired, so that the conventionally known siloxane structure and fluorine-based resin powder have It is presumed that a new effect far exceeding lubricity and solvent crack resistance is exhibited by the above-described interaction between the components of the present invention.

In the present invention, the polyarylate having the structural unit represented by the formula (1) needs to have a viscosity average molecular weight of 30,000 to 105,000,
It is preferably from 35,000 to 95000. 300
If it is less than 00, sufficient abrasion resistance cannot be obtained.
If the amount exceeds the above range, the interaction between the polyarylate structure, the polycarbonate structure, and the siloxane structure becomes difficult to develop, and as a result, the surface lubricity is impaired and the blade is turned up in an environment of high temperature and high humidity, which is not preferable.

The viscosity average molecular weight of the polycarbonate having the structural unit represented by the formula (2) is 25,000 to 5
Needs to be 5000 and 25000 to 450
00 is preferred. If it is less than 25,000, sufficient abrasion resistance cannot be obtained, and if it exceeds 55,000, the interaction between the polyarylate structure, the polycarbonate structure, and the siloxane structure becomes difficult to develop, and as a result, surface lubricity is impaired, It is not preferable because the blade may be turned up under the environment.

The viscosity average molecular weight (Ma) of the polyarylate and the viscosity average molecular weight (Mc) of the polycarbonate
Needs to be Ma> Mc. The relationship between the viscosity average molecular weight of the polyarylate and the polycarbonate is Ma>
If it is no longer Mc, the interaction between the polyarylate structure, the polycarbonate structure and the siloxane structure becomes insufficient, and as a result, the wear resistance is impaired or the blade is turned up in a high temperature and high humidity environment, which is not preferable. .

Further, the detailed mechanism is sufficiently elucidated.
Although it has not come, R in the formula (1)¹, R^Two, R^Fiveas well as
R⁶Is a methyl group, and R^Three, R^Four, R⁷, R⁸, R⁹And R
^TenIs a polyarylate having a structural unit in which is a hydrogen atom
And R in formula (2)¹¹~ R¹⁴Is a hydrogen atom
Yes, R^FifteenAnd R¹⁶Is X^TwoTogether with a cyclohexylidene group
Containing a polycarbonate having a structural unit that is
R in equation (3) ¹⁷~ R²⁰Is a methyl group, and R^{twenty one}
And R^{twenty two}Is a hydrogen atom and R in the formula (4) ^{twenty three}~ R²⁶
Is a hydrogen atom, and R²⁷And R²⁸Is X^ThreeWith cyclohe
Each of the copolymers having a structural unit that is a xylidene group
And further use fluorocarbon resin powder.
Especially stable from the beginning to the end of durability
It can improve lubricity, solvent crack resistance, etc.
it can.

This is because the polyarylate structure has the formula (1)
R in¹, R^Two, R^FiveAnd R⁶Is a methyl group, and R^Three,
R^Four, R⁷, R⁸, R⁹And R^TenIs a hydrogen atom and polycarbonate
-Carbonate structure is represented by R in the formula (2)¹¹~ R¹⁴Is a hydrogen source
Child and R^FifteenAnd R¹⁶Is X ^TwoWith cyclohexylide
And the siloxane structure is represented by R in the formula (3).¹⁷~
R²⁰Is a methyl group, and R^{twenty one}And R^{twenty two}Is a hydrogen atom
R in equation (4)^{twenty three}~ R²⁶Is a hydrogen atom, and R²⁷Passing
And R²⁸Is X^ThreeTogether with a cyclohexylidene group
Closely related, how to enter between each molecular chain, each
How to break the crystallinity
The innumerable molecular groups and the order of intramolecular orientational order are different.
It is presumed that there is
High surface lubricity and durability against solvent until durability after holding
It is presumed that cracking can be improved.
You.

Further, a polyarylate having a structural unit represented by the formula (1), a polycarbonate having a structural unit represented by the formula (2), and a polycarbonate having the structural units represented by the formulas (3) and (4). Dissolve and mix the polymer in a solvent,
By containing a blend material obtained by reprecipitation with a poor solvent, the effects of the present invention can be further exhibited.

The dissolution-reprecipitation method is carried out by a conventional method. For example, a polyarylate having a structural unit represented by the formula (1) in a soluble solvent such as dichloromethane or chloroform, a structural unit represented by the formula (2) And the copolymer having the structural units represented by the formulas (3) and (4) are sufficiently dissolved. Next, the mixed polymer solution is reprecipitated from a poor solvent such as methanol or water to obtain a flocculent polymer. This is vacuum dried to obtain a blend material. This material is a polyallylate having a constitutional unit represented by the formula (1), a polycarbonate having a constitutional unit represented by the formula (2), and a composition represented by the formulas (3) and (4), each of which is simply blended. Solubility and paint stability are improved over copolymers having units.
This method comprises any of a polyarylate having a structural unit represented by the formula (1), a polycarbonate having a structural unit represented by the formula (2), and a structural unit represented by the formulas (3) and (4). Although copolymers are also effective, polycarbonate A type and polyarylate Z, which are particularly poorly soluble, are effective.
The mold is effective for improving the characteristics.

Although the detailed mechanism has not been fully elucidated, each polymer is previously blended in a solution to form a polyarylate structure having a structural unit represented by the formula (1), which is represented by the formula (2). A polycarbonate structure having a structural unit represented by formula (3) and a copolymer structure having a structural unit represented by formula (4) can be highly blended;
It is presumed that the obtained blend material has easily entered a space between the respective molecular chains, so that it has become easier to exhibit new characteristics due to the interaction with the fluororesin powder.

First, in the case of polycarbonate A type or polyarylate Z type having low solubility, it is considered that molecules of different structures are blended, and thus the crystallinity of each is lost. Is considered to be improved, and it is presumed that gelation and the like during storage can be further suppressed. Further, the cause of the decrease in the electrophotographic characteristics is estimated as follows.

The phthalate ester structure, which is one of the factors that make polyarylate excellent in mechanical strength, is expected to be one of the factors for trapping carriers when combined with a charge transporting material. A polycarbonate having a structural unit represented by the formula (2), and a formula (3)
And the copolymer having the structural unit represented by the formula (4) exists near the polyarylate having the structural unit represented by the formula (1) on a molecular level, and therefore, some mutual interaction with the phthalate ester structure occurs. It is presumed that the action occurs to reduce the carrier trapping due to the phthalate structure. Furthermore, residual impurities (residual monomers and chlorides, etc.) in the polymer are one of the causes of deterioration of various properties,
It is considered that the improved solubility of the blend system of the present invention increases the ease of purification and suppresses the deterioration of electrophotographic properties.

Since the blend at the molecular level increases the intramolecular density and has both an amorphous portion and a crystalline portion in the same molecule, the intramolecular stress generated at the time of forming a coating film can be alleviated. It is presumed that the internal stress is maintained even if a chemical causing a solvent crack enters, and no crack occurs.

In the present invention, the copolymer having the structural units represented by the formulas (3) and (4) preferably has a viscosity average molecular weight of 10,000 to 200,000, and particularly preferably 15,000 to 100,000. Is preferred.

The mass mixing ratio (Wa) of the polyarylate having the structural unit represented by the formula (1), the mass mixing ratio (Wc) of the polycarbonate having the structural unit represented by the formula (2), and the formula (Wc) The mass mixing ratio (Ws) of the copolymer having the structural units represented by 3) and Formula (4) is Wa / W
c = 95/5 to 50/50, and Ws
It is preferable that / (Wa + Wc) = 1/99 to 30/70.

Further, the mass mixing ratio of the fluororesin powder (W
f) is Wf / (Wa + Wc + Ws) = 1 / 100-5
It is preferably 0/100.

Hereinafter, the structure of the electrophotographic photosensitive member used in the present invention will be described.

The electrophotographic photosensitive member of the present invention has a photosensitive layer on a support. The photosensitive layer may be a single-layer type containing a charge transport material and a charge generation material in the same layer, or may be a multilayer type in which a charge transport layer and a charge generation layer are separated from each other. preferable. In any case, at least the surface layer of the electrophotographic photoreceptor has a polyarylate having a structural unit represented by the formula (1), a polycarbonate having a structural unit represented by the formula (2), a formula (3) and a formula (4). ), And a fluororesin powder, wherein the polyarylate has a viscosity average molecular weight (Ma) of 30,000 to 105,000, and the polycarbonate has a viscosity average molecular weight (Mc) of 25,000.
５５55000 and Ma> Mc.

The support to be used is not limited as long as it has conductivity, and examples thereof include metals such as aluminum and stainless steel, or metals having a conductive layer, paper, and plastic. And the like.

When the exposure light such as LBP is a laser light,
A conductive layer may be provided between the support and the photosensitive layer for the purpose of preventing interference fringes due to scattering or covering a scratch on the support. This can be formed by dispersing conductive powder such as carbon black or metal particles in a binder resin. The thickness of the conductive layer is preferably 5 to 40 μm, particularly preferably 1 to 40 μm.
0 to 30 μm is preferred.

Further, an intermediate layer having an adhesion function and a barrier function may be provided thereon. Examples of the material of the intermediate layer include polyamide, polyvinyl alcohol, polyethylene oxide, ethyl cellulose, casein, polyurethane, and polyether urethane. They are,
It is applied after being dissolved in an appropriate solvent. The thickness of the intermediate layer is 0.
It is preferably from 0.5 to 5 μm, particularly preferably from 0.3 to 1 μm.

The charge generation layer is formed on the intermediate layer.
Examples of the charge generation material used in the present invention include selenium-tellurium, pyrylium, thiapyrylium-based dyes, phthalocyanine, anthantrone, dibenzpyrenequinone, trisazo, cyanine, disazo, monoazo, indigo, quinacridone, and asymmetric quinocyanine-based pigments. No. In the case of the function separation type, the charge generation layer is formed by mixing the charge generation material with a homogenizer, an ultrasonic dispersion, a ball mill, a vibration ball mill, a sand mill, an attritor, a roll mill or a liquid collision type high speed with a binder resin and a solvent in an amount of 0.3 to 4 times. The dispersion is sufficiently dispersed by a method such as a disperser, and a dispersion is applied and dried to form a dispersion liquid. The thickness of the charge generation layer is preferably 5 μm or less, and particularly preferably 0.1 to 2 μm.

The charge transport layer is formed by applying and drying a coating material in which a charge transport material and a binder resin of the present invention are dissolved in a solvent. Examples of the charge transport material used include a triarylamine compound, a hydrazone compound, a stilbene compound, a pyrazoline compound, an oxazole compound, a triallylmethane compound, and a thiazole compound. These are combined with 0.5 to 2 times the amount of the binder resin, applied and dried to form a charge transport layer. The thickness of the charge transport layer is preferably 5 to 40 μm, and particularly preferably 15 to 30 μm.

FIG. 1 shows a schematic configuration of an electrophotographic apparatus using a process cartridge having the electrophotographic photosensitive member of the present invention.

In FIG. 1, reference numeral 1 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is driven to rotate around a shaft 2 at a predetermined peripheral speed in a direction indicated by an arrow. In the rotation process, the electrophotographic photosensitive member 1 is uniformly charged at a predetermined positive or negative potential on its peripheral surface by the primary charging means 3, and then is exposed from exposure means (not shown) such as slit exposure or laser beam scanning exposure. It receives exposure light 4 that is emphasized and modulated according to a time-series electric digital image signal of target image information to be output. In this way, an electrostatic latent image corresponding to the target image information is sequentially formed on the peripheral surface of the electrophotographic photosensitive member 1.

The formed electrostatic latent image is then transferred to developing means 5
Is transferred to the transfer material 7 taken out of the paper supply unit (not shown) between the electrophotographic photosensitive member 1 and the transfer means 6 in synchronization with the rotation of the electrophotographic photosensitive member 1 and fed. The toner image formed and carried on the surface of the photoconductor 1 is sequentially transferred by the transfer unit 6.

The transfer material 7 to which the toner image has been transferred is separated from the surface of the electrophotographic photosensitive member, introduced into the image fixing means 8 and subjected to image fixing, thereby being printed out as an image formed product (print, copy) outside the apparatus. Be out.

After the transfer of the image, the surface of the electrophotographic photosensitive member 1 is cleaned by removing the untransferred toner by the cleaning means 9, and is further subjected to a charge removal treatment by the pre-exposure light 10 from the pre-exposure means (not shown). After that, it is repeatedly used for image formation. When the primary charging unit 3 is a contact charging unit using a charging roller or the like, the pre-exposure is not necessarily required.

In the present invention, among the above-mentioned components such as the electrophotographic photosensitive member 1, the primary charging means 3, the developing means 5 and the cleaning means 9, a plurality of components are housed in a container and integrally combined as a process cartridge. The process cartridge may be configured to be detachable from an electrophotographic apparatus body such as a copying machine or a laser beam printer. For example, at least one of the primary charging unit 3, the developing unit 5, and the cleaning unit 9 is integrally supported with the electrophotographic photosensitive member 1 to form a cartridge, and is attached to and detached from the apparatus main body by using a guide unit 12 such as a rail of the apparatus main body. A flexible process cartridge 11 can be provided.

When the electrophotographic apparatus is a copying machine or a printer, the exposure light 4 is reflected light or transmitted light from the original, or the original is read by a sensor, converted into a signal, and a laser beam is emitted according to the signal. Beam scanning, LED
The light is emitted when the array is driven or the liquid crystal shutter array is driven.

The electrophotographic photosensitive member of the present invention can be used not only for an electrophotographic copying machine but also for a laser beam printer,
It can be widely used in electrophotographic applications such as CRT printers, LED printers, faxes, liquid crystal printers, and laser plate making.

[0083]

The present invention will be described in more detail with reference to the following examples. In the examples, “parts” means “parts by mass”.

The polyarylate having the structural unit represented by the formula (1), the polycarbonate having the structural unit represented by the formula (2), and the formulas (3) and (4) used in the present invention.
The copolymer having the structural unit represented by was synthesized by a conventional method. Further, the viscosity average molecular weight was determined by a conventional method.

A polyarylate having a structural unit represented by the formula (1), a polycarbonate having a structural unit represented by the formula (2), and a copolymer having the structural units represented by the formulas (3) and (4) As a means of blending, a method of blending each polymer with a powder, a method of blending while dissolving in a solvent, and the like are applicable.In the present invention, the polymer is dissolved in a solvent and reprecipitated with a poor solvent. The method of blending is effective. As a procedure, first, each polymer was weighed at an arbitrary mixing ratio, and was sufficiently dissolved in 10 times (wt) of dichloromethane. Then, 10 times the amount of the dissolving solvent (w
This polymer solution was gradually added dropwise while stirring the methanol in t). A white flocculent blend polymer was obtained in this methanol. This was vacuum dried and used as flakes.

Example 1 An aluminum cylinder having a diameter of 30 mm × 254 mm was used as a support, and a paint composed of the following materials was applied on the support by a dipping method.
The composition was thermally cured at 40 ° C. for 30 minutes to form a conductive layer having a thickness of 15 μm.

Conductive pigment: Barium sulfate treated with SnO ₂ coating 10 parts Pigment for resistance control: titanium oxide 2 parts Binder resin: phenol resin 6 parts Leveling material: silicone oil 0.001 part Solvent: methanol / methoxypropanol 0.2 / 0.8 20 parts

Next, 3 parts of N-methoxymethylated nylon and 3 parts of copolymerized nylon were added thereto with 65 parts of methanol /
A solution dissolved in a mixed solvent of 30 parts of n-butanol was applied by a dipping method and dried to form an intermediate layer having a thickness of 0.5 μm.

Next, in the characteristic X-ray diffraction of CuKα, the Bragg angles (2θ ± 0.2 °) of 9.0 °, 14.2 °,
Sand mill using 4 parts of oxytitanium phthalocyanine (TiOPc) having strong peaks at 23.9 ° and 27.1 °, 2 parts of polyvinyl butyral (trade name: Eslec BM2, manufactured by Sekisui Chemical) and 60 parts of cyclohexanone using φlmm glass beads After dispersion by an apparatus for 4 hours, 100 parts of ethyl acetate was added to prepare a dispersion for a charge generation layer. This is applied by a dipping method and dried, and the film thickness is set to 0.
A 3 μm charge generation layer was formed.

Next, in order to form a charge transport layer, a paint for the charge transport layer was prepared. Bisphenol C type {Structural unit example (1) -2) 50 parts of polyarylate (viscosity average molecular weight 60000), bisphenol Z type {Structural unit example (2) -13} polycarbonate (viscosity average molecular weight 4)
0000) and 10 parts of the modified polycarbonate (viscosity average molecular weight 40000) shown in Structural Unit Example (3) -1 and Structural Unit Example (2) -13. This blend polymer 100
Part, polytetrafluoroethylene (trade name: Lubron L-2,
10 parts of Daikin Industries, Ltd.), 0.5 parts of a fluorine-based graft polymer (trade name: Aron GF300, manufactured by Toa Gosei Chemical Industry Co., Ltd.), 500 parts of monochlorobenzene /
It was dissolved in 500 parts of dichloromethane and dispersed in a stainless steel ball mill for 48 hours. 90 parts of an amine compound having the following structural formula was added to the obtained dispersion.

[0091]

Embedded image 10 parts of amine compound of the following structural formula

[0092]

Embedded image Was dissolved to obtain a paint for a charge transport layer. This paint is applied by a dipping method, dried at 120 ° C. for 1 hour, and has a thickness of 26 μm.
Was formed.

Next, evaluation will be described. The equipment is Canon's LBP "Image Class 4000"
(Process speed: 144.5 mm / sec) was modified and used. For the remodeling, a pre-exposure with a fuse lamp was attached just before the charger, and the lamp was used only when the residual potential was measured. The potential measurement was performed by setting the dark part to Vd, the laser light irradiation part to Vl, and the pre-exposure irradiation part to Vr. The produced electrophotographic photoreceptor was subjected to paper passing durability in this apparatus under an environment of 23 ° C./55% RH. The sequence is one for every two prints
In the intermittent mode in which the printing was stopped twice, the potential was measured when 3,000 sheets were printed, and the paper passing durability was continued up to 10,000 sheets, and the shaving amount of the electrophotographic photosensitive member was measured. Also,
4000 in high temperature and high humidity environment of 32.5 ° C / 85% RH
Zero paper passing durability was performed. The sequence is an intermittent mode in which the printing is stopped once for every two prints, the print is paused for 10 minutes every 500 prints, and the cartridge is repeatedly inserted and removed every 1000 prints. evaluated. It should be noted that the toner was replenished as needed during a print pause of 10 minutes. Further, for solvent crack resistance, finger grease was adhered to the surface and left for 24 hours, and the presence or absence of solvent cracks was observed under a microscope. To evaluate the pot life, each charge transport layer paint was allowed to stand in a closed container at room temperature (23 ° C.) for one week, and then the dissolved state was observed. Table 5 shows the results.

(Example 2) As a blend polymer to be used, a polymer obtained by copolymerizing bisphenol Z type {Structural unit example (1) -23} and bisphenol C type {Structural unit example (1) -2} at a mass ratio of 1/1. Arylate (viscosity average molecular weight =
45000) and using the conditions shown in Table 4. Table 5 shows the results.

(Examples 3 to 17) Except that the polymer used, the viscosity average molecular weight, the fluororesin powder, the mixing ratio, and each polymer used as the blend polymer were separately used and the conditions shown in Table 4 were used, Performed in the same manner as in Example 1.
Table 5 shows the results.

(Example 18) A modified LBP "Image Class 4000" (process speed: 235.5 mm / sec) was used as an evaluation apparatus. Modifications include changing the high pressure setting, turning the drive motor
This was done by turning the scanner fast, increasing the primary AC frequency, increasing the amount of laser light, and reviewing the paper feed sequence. The procedure was performed in the same manner as in Example 1 except that the polymer used, the viscosity average molecular weight, the fluororesin powder, the mixing ratio, and each polymer used as the blend polymer were separately used and the conditions shown in Table 4 were used. Table 5 shows the results.

(Comparative Examples 1 to 5) [0097] The polymers used, the viscosity average molecular weight, the fluororesin powder, the mixing ratio, and the polymers used as the blended polymers were separately used and the conditions shown in Table 4 were used. Performed in the same manner as 1. Table 5 shows the results.

[0098]

[Table 13]

[0099]

[Table 14]

[0100]

[Table 15]

*: "Reprecipitation" means blended by dissolution / reprecipitation. "Separate" means that added sequentially during dissolution.

[0102]

[Table 16] **: No solvent crack = ○: Solvent crack occurred = × ***: Dissolved = ：: Gelled or not dissolved = × ***: Cleaning Blade not turned up =
: The cleaning blade was turned up = ×: The cleaning blade was not turned up, but printing was not possible up to 40,000 sheets = △

In Examples 1 to 18, good results were obtained for all evaluation items. However, in Comparative Examples 1 and 4, image defects occurred when the durability was 40,000 sheets or less. The cause was abrasion of the electrophotographic photosensitive member. In Comparative Examples 2, 3, and 5, the cleaning blade was turned up in a high-temperature, high-humidity environment.

As described above, the surface layer of the electrophotographic photosensitive member according to the present invention may be a polyarylate having a structural unit represented by the formula (1), a polycarbonate having a structural unit represented by the formula (2), It contains a copolymer having the structural units represented by (3) and (4), and a fluororesin powder, and the polyarylate has a viscosity average molecular weight (Ma) of 30.
5,000 to 55,000, and the viscosity average molecular weight (Mc) of the polycarbonate is 25,000 to 55000, and Ma> Mc, so that an electrophotographic photoreceptor having excellent mechanical strength and surface lubricity until endurance is obtained. Can be provided. Further, the electrophotographic photoreceptor has good electrophotographic properties, has good coatability at the time of production, and has a good paint pot life, and does not turn over even with a general cleaning blade, and a process cartridge having the electrophotographic photoreceptor. And an electrophotographic apparatus.

[0105]

As described above, the electrophotographic photoreceptor of the present invention has both excellent mechanical strength and surface lubricity until after the endurance, and has good electrophotographic properties. In addition, the improvement of solubility and pot life has expanded the range of choice of materials (constituent units),
A process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus using a process cartridge having an electrophotographic photosensitive member of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electrophotographic photoreceptor 2 axis 3 charging means 4 exposure light 5 developing means 6 transfer means 7 transfer material 8 fixing means 9 cleaning means 10 pre-exposure light 11 process cartridge 12 guide means

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hirotoshi Uesugi 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H068 AA13 AA14 BB25 BB27 BB31 BB52 EA05 FA03 FA27

Claims (8)

[Claims] 1. An electrophotographic photosensitive member having a conductive support and a photosensitive layer, wherein the surface layer of the electrophotographic photosensitive member is a polyarylate having a structural unit represented by the following formula (1): A polycarbonate having a structural unit represented by the following formula (3) and a copolymer having a structural unit represented by the following formula (4), and a fluorine-based resin powder, and a viscosity average molecular weight (Ma) of the polyarylate. ) Is 30,000
An electrophotographic photoreceptor, wherein the viscosity average molecular weight (Mc) of the polycarbonate is 25,000 to 55000, and Ma> Mc. Embedded image In the formula, X ¹ is a carbon atom or a single bond (in this case, R ⁵ and R ^{5
6 represents} none), R ^{1 to} R ⁴ represent a hydrogen atom, a halogen atom, an optionally substituted alkyl group, or an optionally substituted aryl group, and R ⁵ and R ⁶ represent a hydrogen atom, a halogen atom, alkyl group which may indicate an optionally substituted alkylidene group is formed by and the aryl group, or R ⁵ may be substituted R ⁶ binds, R ⁷ to R ¹⁰
Represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group, or an optionally substituted aryl group. {Wherein, X ² represents a carbon atom or a single bond (R ¹⁵ and R ¹⁶ story during this), R ^{1 1} ~R ¹⁴ is a hydrogen atom, a halogen atom, an optionally substituted alkyl group, optionally substituted And R ¹⁵ and R ^{16 each} represent a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, or a substituted group formed by combining R ¹⁵ and R ^16. Represents an optionally substituted alkylidene group. (Wherein, R ^{17 to} R ^{22 each} represent a hydrogen atom, a halogen atom, an alkyl group which may be substituted, or an aryl group which may be substituted, and n represents a positive integer.) {Wherein, X ³ represents a carbon atom or a single bond (R ²⁷ and R ²⁸ story during this), R ^{2 3} ~R ²⁶ is a hydrogen atom, a halogen atom, an optionally substituted alkyl group, optionally substituted R ²⁷ and R ²⁸ represent a hydrogen atom, a halogen atom, an alkyl group which may be substituted, an aryl group which may be substituted or a substituted group formed by bonding of R ²⁷ and R ²⁸ Represents an optionally substituted alkylidene group. 2. In the formula (1), R ¹ , R ² , R ⁵ and R ⁶ are a methyl group, and R ³ , R ⁴ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are a hydrogen atom. The electrophotographic photoreceptor according to claim 1, comprising a polyarylate having a structural unit. 3. The polycarbonate according to claim 1, wherein R ^{11 to} R ¹⁴ in the formula (2) are a hydrogen atom, and R ¹⁵ and R ¹⁶ have a structural unit of a cyclohexylidene group together with X ^2. Electrophotographic photoreceptor. 4. In the formula (1), R ¹ , R ² , R ⁵ and R ⁶ are methyl groups, and R ³ , R ⁴ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are hydrogen atoms. A polycarbonate containing a polyarylate having a constitutional unit, and having a constitutional unit in which R ^{11 to} R ¹⁴ in the formula (2) are a hydrogen atom, and R ¹⁵ and R ¹⁶ are a cyclohexylidene group together with X ^2. The electrophotographic photoreceptor according to claim 1. 5. The method according to claim 1, wherein said fluororesin powder is ethylene tetrafluoride resin, ethylene trifluoride ethylene resin, ethylene tetrafluoride-propylene hexafluoride resin, vinyl fluoride resin, vinylidene fluoride resin, 5. The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor is selected from an ethylene chloride resin and a copolymer thereof. 6. A polyarylate having a structural unit represented by the formula (1) and a polycarbonate having a structural unit represented by the formula (2) are dissolved and mixed in a solvent.
The electrophotographic photosensitive member according to claim 1, further comprising a blend material obtained by reprecipitation with a poor solvent. 7. A charging means for charging the electrophotographic photosensitive member according to claim 1 to charge the electrophotographic photosensitive member.
At least one means selected from the group consisting of a developing means for developing the electrophotographic photosensitive member on which the electrostatic latent image is formed with toner, and a cleaning means for collecting residual toner on the electrophotographic photosensitive member after the transfer step A process cartridge which is supported integrally with the electrophotographic apparatus and is detachable from the main body of the electrophotographic apparatus. 8. An electrophotographic photoreceptor according to claim 1, a charging means for charging the electrophotographic photoreceptor, and exposing the charged electrophotographic photoreceptor to form an electrostatic latent image. An electrophotographic apparatus comprising: an exposure unit; a developing unit that develops an electrophotographic photosensitive member on which an electrostatic latent image is formed with toner; and a transfer unit that transfers a toner image on the electrophotographic photosensitive member onto a transfer material. apparatus.