JP2008170977A - Electrophotographic photoreceptor, image forming method and image forming apparatus using the same, and process cartridge for image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly durable electrophotographic photoreceptor of high performance having superior abrasion resistance and satisfactory electrical properties, and further having superior environmental stability. <P>SOLUTION: Disclosed is an electrophotographic photoreceptor including: an electroconductive substrate; a photosensitive layer which is located overlying the electroconductive substrate and which is not radically crosslinked; and an outermost layer which is located overlying the photosensitive layer and which includes a radically crosslinked material, wherein the radically crosslinked material includes a unit at least expressed by Formula (A), wherein: H represents a 1,1-cyclopentane-diyl group, a 1,1-cyclohexane-diyl group, or a 9,9-fluorene-diyl group; each of R<SB>5</SB>and R<SB>6</SB>represents a linear, branched or cyclic alkyl group, having 1 to 6 carbon atoms, a halogen atom, or an aryl group; R<SB>7</SB>represents a hydrogen atom, or an alkyl group having 1 to 4 carbon atoms; and each of i and j is 0 or an integer of from 1 to 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an organic electrophotographic photosensitive member having extremely high wear resistance, and is excellent in electrical characteristics such as chargeability, sensitivity, residual potential accumulation and the like, and has environmental stability against electrical characteristics and image flow. Further, the present invention relates to a highly durable, high-performance and highly stable electrophotographic photosensitive member that is good and is less susceptible to image defects such as reduced resolution and reduced halftone density with respect to oxidizing gas generated from the electrophotographic process. . The present invention also relates to an image forming method, an image forming apparatus, and a process cartridge for the image forming apparatus using the long-life, highly stable electrophotographic photosensitive member.

  In recent years, organic photoreceptors (OPC) have been widely used in copying machines, facsimile machines, laser printers, and composite machines in place of inorganic photoreceptors because of their good performance and various advantages. This is because, for example, (1) optical characteristics such as the light absorption wavelength range and the amount of absorption, (2) electrical characteristics such as high sensitivity and stable charging characteristics, and (3) material selection range (4) Ease of manufacturing, (5) Low cost, (6) Non-toxicity, and the like. On the other hand, the diameter of the photoconductor has recently been reduced due to the downsizing of the image forming apparatus, and the high speed of the machine and the maintenance-free movement have been added to increase the durability of the photoconductor. From this point of view, organophotoreceptors are generally soft because the charge transport layer is mainly composed of a low molecular charge transport material and an inert polymer. There is a drawback that wear is likely to occur due to a mechanical load. In addition, due to the demand for higher image quality, the cleaning blade is required to increase its rubber hardness and contact pressure for the purpose of improving the cleaning property as the particle size of the toner particles is reduced. This also promotes wear of the photoreceptor. It is a factor. Such abrasion of the photoreceptor deteriorates electrical characteristics such as sensitivity deterioration and chargeability, and causes abnormal images such as image density reduction and background stains. Further, scratches where wear is locally generated cause streak-like stain images due to poor cleaning. Therefore, attempts to improve the wear resistance of the organic photoreceptor have been studied from various directions.

  Among them, those having a cross-linked surface layer obtained by curing a polyfunctional radical curable monomer (see, for example, Patent Document 1) can use a monomer having a large amount of functional groups to form a dense three-dimensional network structure and high wear resistance. It is noted that a cured film can be instantly formed by light, heat, and radiation, and that a cured material does not require an acid or base catalyst for the curing reaction and does not adversely affect electrical characteristics. Furthermore, in order to improve the electrical properties of the crosslinked surface layer, a charge transport material having a radical polymerizable functional group is used in combination, and the charge transport structure is fixed in the crosslinked structure (see, for example, Patent Documents 2 and 3). This technique has made it possible to achieve both wear resistance and charge transportability, and to improve the film thickness margin of the crosslinked surface layer.

  On the other hand, a cross-linked surface layer made of a radical curable composition can form a highly cross-linked three-dimensional network structure and high wear resistance can be obtained. However, the curable composition originally has a large amount of polar groups and has a dielectric constant. Therefore, there are problems such as environmental fluctuations such as temperature and humidity and electrical characteristics deterioration such as low resistance and sensitivity reduction due to oxidizing gas generated from the charger, image deterioration such as density change, image flow, resolution reduction etc. is there. On the other hand, by using a polyfunctional monomer in which a part of the functional group is alkyl-substituted (for example, see Patent Document 4), an inert substituent is introduced instead of the functional group to reduce the influence of environmental fluctuations. ing. Furthermore, a technique for improving the environmental stability of the cross-linked surface layer and the adhesion to the lower layer by using a bifunctional monomer with a bisphenol A derivative bifunctional monomer (see, for example, Patent Documents 5 and 6) has been proposed. The peeling of the layer is suppressed.

Although the technologies described above have improved the environmental compatibility of the crosslinked surface layer and the stability against oxidizing gas, increasing the amount of functional groups with the aim of high wear resistance increases the number of polar groups and unreacted functional groups. If the amount of functional groups is reduced, the mechanical strength is lowered. Therefore, the environmental stability and the wear resistance against temperature and humidity and oxidizing gas are still in a contradictory relationship, and the two properties have not been sufficiently compatible.
In recent years, there has been a growing demand for higher image quality and higher durability, and there is an urgent need to achieve both environmental stability and wear resistance at a high level.
Japanese Patent No. 3262488 Japanese Patent No. 3194392 JP 2000-66425 A JP 2006-3863 A Japanese Patent No. 2896823 JP 2006-71856 A

An object of the present invention is to provide a highly durable and high performance electrophotographic photoreceptor having excellent wear resistance and electrical characteristics, and having excellent environmental compatibility. More specifically, while maintaining the high abrasion resistance of the acrylic cross-linked surface layer using polyfunctional monomer, it has high stability against the oxidizing gas generated from the temperature and humidity environment and charger, image density fluctuation and image An object of the present invention is to provide an electrophotographic photosensitive member in which flow and resolution are not easily lowered.
Another object of the present invention is to provide an image forming method, an image forming apparatus, and a process cartridge for an image forming apparatus that use such a highly durable and highly stable long-life photoconductor and realize high image quality over a long period of time.

As a result of intensive studies, the present inventors have found that the above object can be achieved by the following (1) to (11), and have completed the present invention.
That is, the said subject is solved by the following this invention.
(1) In an electrophotographic photoreceptor having at least a photosensitive layer that is not radically cured on a conductive support and a crosslinked surface layer containing a radically cured composition, at least in the radically cured composition of the crosslinked surface layer An electrophotographic photoreceptor comprising a structural unit represented by the following general formula (A).
(In the formula, H represents a 1,1-cyclopentane-diyl group, a 1,1-cyclohexane-diyl group, a 9,9-fluorene-diyl group, and R ₅ and R ₆ are each a straight chain having 1 to 6 carbon atoms. A chain, branched or cyclic alkyl group, a halogen atom or an aryl group is represented, R ₇ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and i and j each represents an integer of 0 to 4)

(2) The radical curable composition is a composition formed by applying at least a radically polymerizable compound represented by the following general formula (B) to the photosensitive layer surface, followed by radical curing. The electrophotographic photosensitive member as described in (1) above, wherein
(In the formula, H represents a 1,1-cyclopentane-diyl group, a 1,1-cyclohexane-diyl group, or a 9,9-fluorene-diyl group, and R ₁ and R ₂ are each a straight chain having 1 to 6 carbon atoms. A chain or branched alkylene group, a 1-ketohexylene group, R ₃ and R ₄ each represent a hydrogen atom or a methyl group, and R ₅ and R ₆ each represent a linear, branched or cyclic group having 1 to 6 carbon atoms. Represents an alkyl group, a halogen atom or an aryl group; R ₇ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; n and m each represents an integer of 0 to 4; i and j each represents 0 to 4 Represents an integer.)

(3) The radical curable composition is a composition formed by applying at least a radically polymerizable compound represented by the following general formula (C) to the surface of the photosensitive layer, followed by radical curing. The electrophotographic photosensitive member as described in (1) above, wherein
(In the formula, H represents 1,1-cyclopentane-diyl group, 1,1-cyclohexane-diyl group, 9,9-fluorene-diyl group, and R ₁₁ , R ₁₂ , R _13, and R ₁₄ are each hydrogen. Represents an atom or a methyl group, R ₅ and R ₆ each represent a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, a halogen atom or an aryl group, and R ₇ represents a hydrogen atom or 1 to 4 carbon atoms. And i and j each represents an integer of 0 to 4.)

(4) The above-mentioned radical curable composition is a composition formed by applying at least a coating solution containing a radical polymerizable compound represented by the following general formula (D) to the surface of the photosensitive layer, followed by radical curing. The electrophotographic photosensitive member as described in (1) above, wherein
(In the formula, H represents a 1,1-cyclopentane-diyl group, a 1,1-cyclohexane-diyl group, or a 9,9-fluorene-diyl group, and R ₁₅ and R ₁₆ each represents a hydrogen atom or a methyl group. , R ₅ and R ₆ each represent a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, a halogen atom or an aryl group; R ₇ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; n represents an integer of 1 to 50, and i and j each represents an integer of 0 to 4.)

(5) The radical curable composition includes at least one of the radical polymerizable compounds represented by the general formulas (B), (C), and (D), and a monomer having three or more radical polymerizable functional groups. The electrophotographic photosensitive member according to any one of the above (2) to (4), which is a composition formed by applying a coating solution to the surface of the photosensitive layer and then radical-curing it.
(6) Charge transport in which the radical curable composition has at least one of the radical polymerizable compounds represented by the general formulas (B), (C), and (D), and one or more radical polymerizable functional groups. The electrophotography as described in any one of (2) to (5) above, which is a composition formed by applying a coating solution containing a functional compound to the surface of the photosensitive layer and then radical curing. Photoconductor.
(7) The electrophotographic photosensitive member according to any one of (1) to (6), wherein the radical curable composition is cured by means using light energy.
(8) Any of the above (1) to (7), wherein the non-radically cured photosensitive layer has a structure in which at least a charge generation layer and a charge transport layer are sequentially laminated on a conductive support. The electrophotographic photoreceptor described in 1.

(9) An image forming method using an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of (1) to (8).
(10) An image forming apparatus comprising at least a charging unit, an exposing unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is any one of (1) to (8). An image forming apparatus characterized by being an electrophotographic photosensitive member.
(11) The electrophotographic photosensitive member according to any one of (1) to (8), and at least one unit selected from a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit Is a process cartridge for an image forming apparatus, characterized by being integrated with the image forming apparatus and detachable from the image forming apparatus.

  By using an electrophotographic photosensitive member having a non-radical-cured photosensitive layer of the present invention and a crosslinked surface layer containing a radical-curing composition containing the structure of the general formula (A), the abrasion resistance is high and good. An electrophotographic photosensitive member having electrical characteristics and excellent environmental stability and gas resistance is realized. Therefore, by using this photoreceptor, it is possible to provide a high-performance and highly reliable image forming method, an image forming apparatus, and a process cartridge for an image forming apparatus that can provide a higher quality image over a long period of time.

Hereinafter, the present invention will be described in detail.
In the present invention, by incorporating the chemical structure of the following general formula (A) into the structure of the radical curable composition that forms the crosslinked surface layer, it has excellent wear resistance and environmental stability that can be widely applied to temperature and humidity. It was also found that it is resistant to oxidizing gas such as ozone gas and nitrogen oxide gas (NOx gas) generated from the charger, and can suppress fluctuations in image density, image flow, and resolution reduction.

(In the formula, H represents a 1,1-cyclopentane-diyl group, a 1,1-cyclohexane-diyl group, or a 9,9-fluorene-diyl group, and R ₅ and R ₆ are each a straight chain having 1 to 6 carbon atoms. A chain, branched or cyclic alkyl group, a halogen atom or an aryl group is represented, R ₇ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and i and j each represents an integer of 0 to 4)

<Reason for the expression of wear resistance>
First, it will be explained that the crosslinked surface layer of the present invention has high wear resistance.
Conventionally, it has been known that a crosslinked surface layer made of a radically curable composition can form a dense three-dimensional network structure, and thereby exhibits high wear resistance. As described in Japanese Patent No. 3262488 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2006-227761, it is important to increase the amount of radical curable functional groups in the cured composition as a factor governing abrasion resistance. For example, in the case of an acrylic group, it is disclosed that by using a monomer having a small acrylic equivalent (a value obtained by dividing the monomer molecular weight by the number of functional groups), a denser three-dimensional crosslinked structure is formed and high wear resistance is achieved. Has been. It is also effective to improve the wear resistance by using a monomer having a large number of functional groups, for example, a monomer having three or more functional groups, or a hexafunctional monomer, and the probability that the molecular weight is increased by polymerizing at least one of the functional groups. Due to the increase. Therefore, when a monomer having a functionality of 2 or less is used as a main component, the mechanical strength is lowered, and it is expected that the abrasion resistance of the crosslinked surface layer is lowered as described in the previous patent document. It was.

  On the other hand, in the present invention, by containing the structural unit represented by the general formula (A) in the radical curable composition, high wear resistance comparable to that obtained when the polyfunctional monomer is used can be obtained. found. This is not seen in the prior art. The reason for this is not clear, but is presumed as follows. In the case where the structural unit of the general formula (A) is contained in the cured composition, the ratio of the functional group is diluted as compared with the polyfunctional aliphatic monomer described in the above publication, and the mechanical strength is considered to decrease. However, although the crosslink density decreases, it is presumed that the effect of entanglement between molecules observed in the linear polymer (in this case, entanglement between structures of the general formula (A)) appears. Moreover, the π-π stacking effect by the π-electron conjugated systems of the general formula (A) appears. In particular, in the structure of the general formula (A), unlike the bisphenol A structure, the two benzene rings are twisted, and it is considered that the above-described effect appears remarkably. Photoreceptor wear occurs when molecules that have been cut by heat from the cleaning action or discharge of the charger are pulled out by the developer or cleaning blade. Presumed to have led to suppression.

  Furthermore, when a charge transporting substance (whether having a functional group or not having a functional group) is included in the cured composition, the structural unit of the general formula (A) having a benzene ring is included. Thus, the charge transport material having a wide π-electron conjugated structure is improved in compatibility with the matrix. For this reason, it is considered that the uniformity of the crosslinked surface layer is improved and the mechanical strength is increased.

<Reasons for environmental stability>
Next, the reason why the crosslinked surface layer of the present invention is resistant to environmental fluctuations and oxidizing gases will be described.
A cross-linked surface layer with high wear resistance originally requires a large amount of reactive substituents to form a dense network structure regardless of the cross-linked structure such as urethane curing, acrylic curing, siloxane curing, and epoxy curing. The crosslinked film also has many polar groups and a high dielectric constant. For this reason, it is vulnerable to environmental fluctuations and oxidizing gases.

  The direction of increasing the functional groups in the radical curing composition described above and the direction of using a large amount of polyfunctional monomers having a large number of functional groups further increase the polar groups (for example, ester groups), resulting in an increase in moisture adsorption. Image flow is likely to occur in a high humidity environment. In addition, when a very dense cross-linked structure is formed, the mobility of the molecule is frozen, and the change of the three-dimensional structure of the charge transport material is suppressed particularly at a low temperature, resulting in a decrease in sensitivity. Further, when the functional group in the cured composition is increased, the unreacted functional group remaining after the curing is increased, and accordingly, the adsorption amount of the highly reactive oxidizing gas generated from the charger is increased, and the crosslinked surface layer is increased. Lowers resistance and lowers resolution.

On the other hand, by including the structural unit of the general formula (A) in the cured composition of the present invention, the influence of environmental fluctuations and oxidizing gas is alleviated. The reason for this is not clear, but is presumed as follows. When the structural unit of the general formula (A) is contained in the cured composition, the molecular weight per functional group is larger than that using the previous polyfunctional aliphatic monomer, and thus the functional group concentration is reduced and the crosslinked surface layer It is thought that the environmental stability of In addition, widening of the actual mesh spacing keeps the molecules moderately mobile, and in addition, the decrease in polar groups does not increase the dielectric constant, thus maintaining high charge transport properties and lowering the sensitivity at low temperatures. Can be suppressed. Further, it is considered that the bulky structure fills the space of the network structure, so that the gas permeability into the membrane is low and the influence of the oxidizing gas can be reduced. In addition, while the bisphenol A structure is linear, it is considered that the structural unit of the general formula (A) has improved space occupancy due to the twist of the benzene ring, and further has suppressed gas permeability.
For the reasons as described above, by incorporating the structural unit of the general formula (A) in the cured composition of the present invention, it is excellent in wear resistance, resistant to environmental fluctuations and oxidizing gases, and simultaneously improves both characteristics. It is thought that the crosslinked surface layer thus obtained could be achieved.

<Regarding the radical curable composition>
Next, the components of the radical curable composition that forms the crosslinked surface layer of the present invention will be described.
In the present invention, the radical curable composition contains the structural unit of the general formula (A), and the radical polymerizable monomer, radical polymerizable oligomer, or polymer having a radical polymerizable functional group having such a structural unit. A radically polymerizable compound such as is cured by light, heat, or electron beam energy to be introduced into the cured product structure in the crosslinked surface layer. At the time of this curing, the structural unit of the general formula (A) is fixed without being decomposed, and the cured surface layer can be confirmed by MS spectrum measurement by pyrolysis GC analysis, characteristic absorption measurement by infrared spectroscopy, or the like. The structural unit of the general formula (A) is 5 to 80% by weight, preferably 10 to 50% by weight, based on the total amount of the radical curable composition. If the structural unit of the general formula (A) in the cured composition is less than 5% by weight, it is not possible to suppress target environmental changes, electrical characteristics with respect to oxidizing gas, and image deterioration. On the other hand, when it exceeds 80% by weight, the curable functional group is decreased and the mechanical strength such as abrasion resistance and scratch resistance is lowered.

  The radical polymerizable monomer, oligomer and polymer have a radical polymerizable functional group, and any functional group may be used as long as it has a carbon-carbon double bond and is capable of radical polymerization. Examples of these radical polymerizable functional groups include 1-substituted ethylene functional groups and 1,1-substituted ethylene functional groups shown below.

(1) Examples of the 1-substituted ethylene functional group include a functional group (P) represented by the following formula.
Functional group (P)
CH ₂ = CH-X ₁ -
(In the formula, X ₁ is an arylene group such as a phenylene group or a naphthylene group which may have a substituent, an alkenylene group which may have a substituent, a —CO— group or a —COO— group. , —CON (R ₂₁ ) — group (R ₂₁ represents an alkyl group such as hydrogen, methyl group or ethyl group, an aralkyl group such as benzyl group, naphthylmethyl group or phenethyl group, or an aryl group such as phenyl group or naphthyl group. Or the —S— group.)
Specific examples of these substituents include a vinyl group, a styryl group, a 2-methyl-1,3-butadienyl group, a vinylcarbonyl group, an acryloyloxy group, an acryloylamide group, and a vinyl thioether group.

(2) Examples of the 1,1-substituted ethylene functional group include a functional group (R) represented by the following formula.
Functional group (R)
_{CH 2 = C (Y) -X} 2 -
(In the formula, Y is an aryl group such as an alkyl group which may have a substituent, an aralkyl group which may have a substituent, a phenyl group which may have a substituent, or a naphthyl group. Group, halogen atom, cyano group, nitro group, alkoxy group such as methoxy group or ethoxy group, -COOR ₂₂ group (R ₂₂ is a hydrogen atom, an alkyl such as an optionally substituted methyl group or ethyl group) Group, an aralkyl group such as benzyl and phenethyl group which may have a substituent, an aryl group such as phenyl group and naphthyl group which may have a substituent, or -CONR ₂₃ R ₂₄ (R ₂₃ and R ₂₄ represents a hydrogen atom, an alkyl group such as an optionally substituted methyl group or an ethyl group, an aralkyl group such as an optionally substituted benzyl group, naphthylmethyl group, or phenethyl group; Also Substituent a phenyl group which may have a represents an aryl group such as a naphthyl group, which may be the same or different from each other.) Further, X ₂ is X ₁ same substituent functional group (P) And a single bond or an alkylene group, provided that at least one of Y and X ₂ is an oxycarbonyl group, a cyano group, an alkenylene group, and an aromatic ring.)
Specific examples of these substituents include an α-acryloyloxy chloride group, a methacryloyloxy group, an α-cyanoethylene group, an α-cyanoacryloyloxy group, an α-cyanophenylene group, and a methacryloylamino group.

In addition, examples of the substituent further substituted with the substituent for X ₁ , X ₂ , and Y include alkyl groups such as halogen atom, nitro group, cyano group, methyl group, and ethyl group, methoxy group, and ethoxy group. And an aryloxy group such as a phenoxy group, an aryl group such as a phenyl group and a naphthyl group, and an aralkyl group such as a benzyl group and a phenethyl group.
Among these radical polymerizable functional groups, acryloyloxy group and methacryloyloxy group are particularly useful. For example, a compound having an acryloyloxy group includes a compound having a hydroxyl group and acrylic acid (salt), acrylic acid halide, acrylic acid. It can be obtained by esterification or transesterification using an ester. A compound having a methacryloyloxy group can be obtained in the same manner. When there are a plurality of radically curable functional groups, they may be the same or different.

<Regarding the radically polymerizable compound of the general formula (B)>
In order to introduce the structural unit of the general formula (A), it is particularly preferable to apply radical curing after coating a coating solution containing a radical polymerizable compound represented by the following general formula (B) on the photosensitive layer. preferable.
(In the formula, H represents a 1,1-cyclopentane-diyl group, a 1,1-cyclohexane-diyl group, or a 9,9-fluorene-diyl group, and R ₁ and R ₂ are each a straight chain having 1 to 6 carbon atoms. Represents a chain or branched alkylene group, 1-ketohexylene group, R ₃ and R ₄ each represent a hydrogen atom or a methyl group, and R ₅ and R ₆ each represent a linear, branched or cyclic group having 1 to 6 carbon atoms. Represents an alkyl group, a halogen atom or an aryl group; R ₇ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; n and m each represents an integer of 0 to 4; i and j each represents 0 to 4 Represents an integer.)

The radically polymerizable compound represented by the general formula (B) can be easily synthesized, for example, by the following production method.
<When n and m are both 0>
Process B1-1

<When n and m are other than 0>
B2-1 process

B2-2 process

Examples of the radical polymerizable compound represented by the general formula B include the following, but are not limited to these compounds.

<Regarding the radically polymerizable compound of the general formula (C)>
In order to introduce the structural unit of the general formula (A), it is particularly preferable to perform radical curing after coating a coating solution containing a radical polymerizable compound represented by the following general formula (C) on the photosensitive layer. preferable.
(In the formula, H represents 1,1-cyclopentane-diyl group, 1,1-cyclohexane-diyl group, 9,9-fluorene-diyl group, and R ₁₁ , R ₁₂ , R _13, and R ₁₄ are each hydrogen. Represents an atom or a methyl group, R ₅ and R ₆ each represent a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, a halogen atom or an aryl group, and R ₇ represents a hydrogen atom or 1 to 4 carbon atoms. And i and j each represents an integer of 0 to 4.)

The radically polymerizable compound represented by the general formula (C) can be easily synthesized, for example, by the following production method.
Process C1-1

Process C1-2

Moreover, it can be easily synthesized even if the C1-1 step is changed to the following method (C2-1 & C-2-2).
Process C2-1

Process C2-2

Further, R ₁₁ to R ₁₄ in the general formula (C) is If all the same group, can be synthesized by the following C3 step.
C3-1 process

C3-2 process

The reaction conditions in each of the above steps can be carried out under the conditions of a conventionally known ring-opening addition reaction of an epoxy ring to a hydroxy group or an esterification reaction with an acid chloride and a hydroxy group.
In addition, conventional synthesis methods other than those described in the steps can be applied. For example, although the (meth) acryloylation step is exemplified in the above step using a reaction between an acid chloride and a hydroxy group, it is also possible to use a dehydration condensation reaction between a suitable acid and a hydroxy group, In acryloylation, the reaction shown in the following (C4) can also be applied.

C4 process

Although the following are illustrated as a radically polymerizable compound represented by general formula (C), it is not limited to these compounds.

<Regarding the radically polymerizable compound of the general formula (D)>
In order to introduce the structural unit represented by the general formula (A), it is particularly preferable to apply a coating solution containing a radical polymerizable compound represented by the following general formula (D) on the photosensitive layer and then to perform radical curing. preferable.
(In the formula, H represents a 1,1-cyclopentane-diyl group, a 1,1-cyclohexane-diyl group, or a 9,9-fluorene-diyl group, and R ₁₅ and R ₁₆ each represents a hydrogen atom or a methyl group. , R ₅ and R ₆ each represent a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, a halogen atom or an aryl group; R ₇ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; n represents an integer of 1 to 50, and i and j each represents an integer of 0 to 4.)

The radically polymerizable compound of the general formula (D) is synthesized by the following route.
D1-1 process

D1-2 process

Although the following are illustrated as a radically polymerizable compound represented by general formula (D), It is not limited to these compounds.

  The radically polymerizable compounds of the general formulas (B), (C), and (D) that are preferably used in the present invention are 10 to 100% by weight, preferably 20 to 70% by weight, based on the total amount of the curable constituent material. is there. If these radically polymerizable compounds are less than 10% by weight, the structural unit of the general formula (A) in the cured composition becomes dilute, and it is not possible to suppress target environmental fluctuations, electric characteristic fluctuations with respect to oxidizing gas, and image deterioration. On the other hand, if it exceeds 70% by weight, there are few curable functional groups, so that mechanical strength such as wear resistance and scratch resistance is lowered, and when the film thickness is increased, the residual potential may be increased.

<Regarding monomer having three or more radical polymerizable functional groups>
The crosslinked surface layer of the present invention contains a cured composition having the structural unit of the general formula (A), but is radically polymerizable for the purpose of adjusting the wear resistance, hardness, coating solution viscosity, curing rate, etc. A monomer having three or more functional groups can be mixed and used. Examples of the radical polymerizable functional group include those described above for the radical polymerizable compound, and acryloyloxy group and methacryloyloxy group are particularly useful.
Examples of the tri- or higher functional radical polymerizable monomer include the following, but are not limited to these compounds.

  That is, examples of the tri- or higher functional radical polymerizable monomer suitably used in the present invention include trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, trimethylolpropane alkylene-modified triacrylate, trimethylolpropane ethyleneoxy. Modified (hereinafter EO modified) triacrylate, trimethylolpropane propyleneoxy modified (hereinafter PO modified) triacrylate, trimethylolpropane caprolactone modified triacrylate, trimethylolpropane alkylene modified trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA) ), Glycerol triacrylate, glycerol epichlorohydrin modified ECH modified) triacrylate, glycerol EO modified triacrylate, glycerol PO modified triacrylate, tris (acryloxyethyl) isocyanurate, dipentaerythritol hexaacrylate (DPHA), dipentaerythritol caprolactone modified hexaacrylate, dipentaerythritol hydroxypentaacrylate Alkylated dipentaerythritol pentaacrylate, alkylated dipentaerythritol tetraacrylate, alkylated dipentaerythritol triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, EO-modified triacrylate phosphate, 2,2 , 5,5-Tetrahydroxymethylcyclopentanone Such as tigers acrylate and the like, which may be mixed using a single or two or more kinds.

  The amount of the monomer having three or more radically polymerizable functional groups that can be mixed and used in the present invention is 0 to 90% by weight, preferably 0 to 50% by weight, based on the total amount of the curable constituent material. In order to fully exhibit the electrical characteristics and image stability with respect to environmental fluctuations and oxidizing gases, the amount of the radical polymerizable compound represented by the general formulas (B), (C), and (D) should be equal or less. preferable.

<Regarding a charge transporting compound having one or more radically polymerizable functional groups>
The crosslinked surface layer of the present invention contains a curable composition having the structural unit of the general formula (A), but is intended to improve the charge transport property of the crosslinked surface layer and maintain good sensitivity and low residual potential over a long period of time. Thus, a charge transporting compound having one or more radically polymerizable functional groups can be mixed and used. Furthermore, this makes it possible to increase the thickness of the cross-linked surface layer and to achieve a longer life until the cross-linked surface layer is worn away. In addition, since the cross-linked surface layer can be thickened, the influence of scratches due to adhesion of carrier and paper powder can be reduced.

  The charge transporting compound having one or more radically polymerizable functional groups used in the present invention is a hole transporting structure such as triarylamine, hydrazone, pyrazoline, carbazole, such as condensed polycyclic quinone, diphenoquinone, cyano group. And a compound having an electron transport structure such as an electron-withdrawing aromatic ring having a nitro group and a radically polymerizable functional group. Examples of the radical polymerizable functional group include those described above for the radical polymerizable compound, and acryloyloxy group and methacryloyloxy group are particularly useful. Although the number of radically polymerizable functional groups in one molecule may be one or more, it is easy to obtain a smooth surface property by suppressing internal stress of the crosslinked surface layer, and to maintain good electrical properties. It is preferable that there is one radical polymerizable functional group. When the charge transporting compound has two or more radically polymerizable functional groups, the bulky charge transporting compound is fixed in the cross-linking with a plurality of bonds, resulting in unevenness from the charge transporting structure and the number of functional groups. , Cracks, and film peeling may occur. In addition, the intermediate structure (cation radical) at the time of charge transport cannot be stably maintained due to the large strain, and the sensitivity is lowered and the residual potential is easily increased due to charge trapping. As the charge transporting structure of the charge transporting compound having a radical polymerizable functional group, a triarylamine structure is preferable because of its high mobility, and among them, a compound represented by the following general formula (1) or (2) is used. If so, electrical characteristics such as sensitivity and residual potential are favorably sustained.

[In the formula, R ₁₀₁ represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a cyano group, a nitro group, A group, an alkoxy group, —COOR ₄₁ (R ₄₁ represents a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or an aryl group which may have a substituent. ), A halogenated carbonyl group or CONR ₄₂ R ₄₃ (R ₄₂ and R ₄₃ have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent or a substituent. Represents an aryl group which may be the same or different, and Ar ₁ and Ar ₂ represent a substituted or unsubstituted arylene group, which may be the same or different. . Ar ₃ and Ar ₄ represent a substituted or unsubstituted aryl group, and may be the same or different. X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether divalent group, an oxygen atom, a sulfur atom, or a vinylene group. Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, or an alkyleneoxycarbonyl divalent group. m and n represent an integer of 0 to 3. ]

Specific examples of general formulas (1) and (2) are shown below.
In the general formulas (1) and (2), in the substituent of R ₁₀₁ , examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group, and examples of the aryl group include a phenyl group and a naphthyl group. The aralkyl group includes a benzyl group, a phenethyl group, and a naphthylmethyl group, and the alkoxy group includes a methoxy group, an ethoxy group, a propoxy group, and the like. These include a halogen atom, a nitro group, a cyano group, and a methyl group. Substituted with an alkyl group such as an ethyl group, an alkoxy group such as a methoxy group or an ethoxy group, an aryloxy group such as a phenoxy group, an aryl group such as a phenyl group or a naphthyl group, an aralkyl group such as a benzyl group or a phenethyl group, etc. May be.
Among the substituents for R ₁₀₁ , particularly preferred are a hydrogen atom and a methyl group.

Ar ₃ and Ar ₄ represent a substituted or unsubstituted aryl group, and in the present invention, the aryl group includes a condensed polycyclic hydrocarbon group, a non-condensed cyclic hydrocarbon group, and a heterocyclic group.
The condensed polycyclic hydrocarbon group preferably has 18 or less carbon atoms forming a ring, for example, a pentanyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptaenyl group, a biphenylenyl group, an as (asym) -Indacenyl group, s (sym) -indacenyl group, fluorenyl group, acenaphthylenyl group, preadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrenyl group, aceanthrylenyl group , Triphenylyl group, pyrenyl group, chrycenyl group, naphthacenyl group and the like.

Examples of the non-fused cyclic hydrocarbon group include monovalent groups of monocyclic hydrocarbon compounds such as benzene, diphenyl ether, polyethylene diphenyl ether, diphenyl thioether and diphenyl sulfone, or biphenyl, polyphenyl, diphenylalkane, diphenylalkene, diphenylalkyne, Monovalent groups of non-condensed polycyclic hydrocarbon compounds such as triphenylmethane, distyrylbenzene, 1,1-diphenylcycloalkane, polyphenylalkane, and polyphenylalkene, or ring assemblies such as 9,9-diphenylfluorene And monovalent groups of hydrocarbon compounds.
Examples of the heterocyclic group include monovalent groups such as carbazole, dibenzofuran, dibenzothiophene, oxadiazole, and thiadiazole.

The aryl group represented by Ar ₃ or Ar ₄ may have a substituent as shown below, for example.
(1) Halogen atom, cyano group, nitro group and the like.
(2) an alkyl group;
Preferably, C ₁ -C ₁₂ especially C ₁ -C _8, more preferably a straight or branched alkyl group of C ₁ -C _4, in the alkyl group a fluorine atom, a hydroxyl group, a cyano group, C ₁ -C ₄ alkoxy group which may have a phenyl group or a halogen atom, C ₁ -C ₄ alkyl or C ₁ -C ₄ phenyl group substituted with an alkoxy group. Specifically, methyl group, ethyl group, n-butyl group, i-propyl group, t-butyl group, s-butyl group, n-propyl group, trifluoromethyl group, 2-hydroxyethyl group, 2-ethoxyethyl Group, 2-cyanoethyl group, 2-methoxyethyl group, benzyl group, 4-chlorobenzyl group, 4-methylbenzyl group, 4-phenylbenzyl group and the like.

(3) an alkoxy group (—OR ₄₄ );
R ₄₄ represents an alkyl group defined in (2). Specifically, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, t-butoxy group, n-butoxy group, s-butoxy group, i-butoxy group, 2-hydroxyethoxy group, benzyloxy group And a trifluoromethoxy group.
(4) aryloxy group;
Examples of the aryl group include a phenyl group and a naphthyl group. It may contain an alkoxy group having C ₁ -C _4, alkyl group, or a halogen atom C ₁ -C ₄ as a substituent. Specific examples include a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a 4-methoxyphenoxy group, and a 4-methylphenoxy group.
(5) an alkyl mercapto group or an aryl mercapto group;
Specific examples include a methylthio group, an ethylthio group, a phenylthio group, and a p-methylphenylthio group.

(6) Substituent represented by the following formula
(In the formula, R ₄₅ and R ₄₆ each independently represents a hydrogen atom, an alkyl group defined in (2) above, or an aryl group. Examples of the aryl group include a phenyl group, a biphenyl group, and a naphthyl group. these C ₁ -C ₄ alkoxy groups, C ₁ -C good .R ₄₅ and R ₄₆ may contain, as a substituent, an alkyl group or a halogen atom ₄ may be linked to form a ring.)
Specifically, amino group, diethylamino group, N-methyl-N-phenylamino group, N, N-diphenylamino group, N, N-di (tolyl) amino group, dibenzylamino group, piperidino group, morpholino group And pyrrolidino group.

(7) An alkylenedioxy group or an alkylenedithio group such as a methylenedioxy group or a methylenedithio group.
(8) A substituted or unsubstituted styryl group, a substituted or unsubstituted β-phenylstyryl group, a diphenylaminophenyl group, a ditolylaminophenyl group, and the like.

On the other hand, the arylene group represented by Ar ₁ or Ar ₂ is a divalent group derived from the aryl group represented by Ar ₃ or Ar ₄ .
X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group.
The substituted or unsubstituted alkylene group is a C _{1 to} C ₁₂ , preferably C _{1 to} C ₈ , more preferably a C _{1 to} C ₄ linear or branched alkylene group, and these alkylene groups include a fluorine atom, a hydroxyl group, a cyano group, an alkoxy group of C ₁ -C _4, a phenyl group or a halogen atom, a phenyl group substituted with an alkyl group or a C ₁ -C ₄ alkoxy group C ₁ -C ₄ It may be. Specifically, methylene group, ethylene group, n-butylene group, i-propylene group, t-butylene group, s-butylene group, n-propylene group, trifluoromethylene group, 2-hydroxyethylene group, 2-ethoxyethylene. Group, 2-cyanoethylene group, 2-methoxyethylene group, benzylidene group, phenylethylene group, 4-chlorophenylethylene group, 4-methylphenylethylene group, 4-biphenylethylene group and the like.

The substituted or unsubstituted cycloalkylene group is a C _{5 to} C ₇ cyclic alkylene group, and these cyclic alkylene groups include a fluorine atom, a hydroxyl group, a C _{1 to} C ₄ alkyl group, and a C _{1 to} C ₄ alkyl group. It may have an alkoxy group. Specific examples include a cyclohexylidene group, a cyclohexylene group, and a 3,3-dimethylcyclohexylidene group.
Examples of the substituted or unsubstituted alkylene ether divalent group include an alkyleneoxy divalent group such as an ethyleneoxy group and a propyleneoxy group, an alkylenedioxy divalent group derived from ethylene glycol, propylene glycol, and the like, or diethylene glycol, tetra Examples include di- or poly (oxyalkylene) oxy divalent groups derived from ethylene glycol, tripropylene glycol, etc. The alkylene group of the alkylene ether divalent group has a substituent such as a hydroxyl group, a methyl group, or an ethyl group. You may have.

The vinylene group is
Wherein R ₄₇ is hydrogen, an alkyl group (the same as the alkyl group defined in (2) above), an aryl group (the same as the aryl group represented by Ar ₃ or Ar ₄ above), a is 1 or 2, b represents 1-3.

Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, or an alkyleneoxycarbonyl group divalent.
Examples of the substituted or unsubstituted alkylene group include the same alkylene groups as those described above for X.
Examples of the substituted or unsubstituted alkylene ether divalent group include the alkylene ether divalent group of X.
Examples of the alkyleneoxycarbonyl divalent group include a caprolactone-modified divalent group.

Further, the charge transporting compound having a radical polymerizable functional group of the present invention is more preferably a compound having the structure of the following general formula (3).
(Wherein, o, p and q are each an integer of 0 or 1, Ra represents a hydrogen atom or a methyl group, Rb and Rc represent a substituent other than a hydrogen atom and an alkyl group having 1 to 6 carbon atoms, And s and t each represents an integer of 0 to 3. Za is a single bond, a methylene group, an ethylene group,
Represents. )
As the compound represented by the above general formula, a compound having a methyl group or an ethyl group as a substituent for Rb and Rc is particularly preferable.

  The charge transporting compound having the radically polymerizable functional group represented by the general formulas (1) and (2), particularly (3) used in the present invention is polymerized because the double bond between carbon and carbon is opened on both sides. In a polymer that does not become a terminal structure, is incorporated in a chain polymer, and is crosslinked by polymerization with a radically polymerizable monomer having three or more functions, it exists in the main chain of the polymer, and the main chain- Present in the cross-linked chain between the main chains (this cross-linked chain includes an inter-molecular cross-linked chain between one polymer and another polymer, a site with a main chain folded in one polymer, and a main chain. There are intramolecular cross-linked chains that are cross-linked with other sites derived from the polymerized monomer at positions away from this in the chain), but they are also present in the cross-linked chain even if they are present in the main chain Even if the triarylamine structure suspended from the chain moiety is released from the nitrogen atom, It has at least three aryl groups arranged in the shape direction and is bulky, but is not directly bonded to the chain part, but is suspended from the chain part via a carbonyl group etc. Since they are fixed in a certain state, these triarylamine structures can be arranged spatially adjacent to each other in the polymer, so there is little structural distortion in the molecule, and the surface layer of the electrophotographic photoreceptor In this case, it is presumed that an intramolecular structure that is relatively free from interruption of the charge transport pathway can be adopted.

Examples of the charge transporting compound having one or more radically polymerizable functional groups include the following, but are not limited to these compounds.

  The charge transporting compound having a radically polymerizable functional group used in the present invention is not necessarily contained when the cross-linked surface layer is thinner than 4 μm. However, when the cross-linked surface layer is 4 μm or more, the charge transport performance It becomes important to grant. When the cross-linked surface layer is 4 μm or more, the content of the coating liquid component is adjusted so that this component is 20 to 80% by weight, preferably 30 to 70% by weight, based on the total amount of the cross-linked surface layer. When this component is less than 20% by weight, the charge transport performance of the crosslinked surface layer cannot be maintained sufficiently, and deterioration of electrical characteristics such as a decrease in sensitivity and an increase in residual potential appears with repeated use. Moreover, when it exceeds 80 weight%, content of the hardening composition shown by general formula (A) will fall, and high abrasion resistance will not be exhibited. The required electrical characteristics and wear resistance differ depending on the process to be used, so it cannot be said unconditionally, but considering the balance of both characteristics, the range of 30 to 70% by weight is most preferable.

<Regarding Additives Having Other Radical Polymerizable Functional Groups>
The crosslinked surface layer of the present invention contains the structural unit represented by the above general formula (A), but besides this, viscosity adjustment during coating, stress relaxation of the crosslinked surface layer, lower surface energy, Monofunctional and bifunctional radically polymerizable monomers, functional monomers, and radically polymerizable oligomers can be used in combination for the purpose of imparting a function such as a reduction in friction coefficient. Known radical polymerizable monomers and oligomers can be used.

  Examples of the monofunctional radically polymerizable monomer include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, 2-ethylhexyl carbitol acrylate, 3-methoxybutyl acrylate, benzyl acrylate, Examples include cyclohexyl acrylate, isoamyl acrylate, isobutyl acrylate, methoxytriethylene glycol acrylate, phenoxytetraethylene glycol acrylate, cetyl acrylate, isostearyl acrylate, stearyl acrylate, and styrene monomer.

  Examples of the bifunctional radical polymerizable monomer include 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1, Examples include 6-hexanediol dimethacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, bisphenol A-EO modified diacrylate, bisphenol F-EO modified diacrylate, neopentyl glycol diacrylate, and the like.

  Examples of the functional monomer include those substituted with a fluorine atom such as octafluoropentyl acrylate, 2-perfluorooctylethyl acrylate, 2-perfluorooctylethyl methacrylate, 2-perfluoroisononylethyl acrylate, No. 60503, JP-B-6-45770, siloxane repeating units: 20-70 acryloyl polydimethylsiloxane ethyl, methacryloyl polydimethylsiloxane ethyl, acryloyl polydimethylsiloxane propyl, acryloyl polydimethylsiloxane butyl, diacryloyl polydimethylsiloxane Examples include vinyl monomers having a polysiloxane group such as diethyl, acrylates and methacrylates.

Examples of the radical polymerizable oligomer include epoxy acrylate, urethane acrylate, and polyester acrylate oligomers.
However, when a large amount of monofunctional and bifunctional radically polymerizable monomers and radically polymerizable oligomers are contained, the three-dimensional cross-linking density of the cross-linked surface layer is substantially reduced, resulting in a decrease in wear resistance. For this reason, the content of these monomers and oligomers is limited to 30% by weight or less, preferably 20% by weight or less, based on the total amount of the curable constituent material of the crosslinked surface layer.

<Regarding the polymerization initiator>
The crosslinked surface layer of the present invention contains at least the structural unit represented by the above general formula (A) in the radical curable composition, but is crosslinked to efficiently advance the curing reaction as necessary. A polymerization initiator may be contained in the surface layer coating solution.

  Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2- Acetophenone-based or ketal-based photopolymerization initiators such as methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, Benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether Benzoin ether photopolymerization initiators such as benzoin isopropyl ether, benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoylphenyl ether, acrylated benzophenone, Benzophenone photopolymerization initiators such as 1,4-benzoylbenzene, thioxanthones such as 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone Examples of photopolymerization initiators and other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoic acid. Phenylethoxyphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10 -Phenanthrene, an acridine type compound, a triazine type compound, an imidazole type compound is mentioned. Moreover, what has a photopolymerization acceleration effect can also be used individually or in combination with the said photoinitiator. Examples include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, 4,4'-dimethylaminobenzophenone, and the like.

As the thermal polymerization initiator, 2,5-dimethylhexane-2,5-dihydroperoxide, dicumyl peroxide, benzoyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di ( Peroxybenzoyl) hexyne-3, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, lauroyl peroxide, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) B) Peroxide-based initiators such as propane, azo-based compounds such as azobisisobutyronitrile, azobiscyclohexanecarbonitrile, methyl azobisisobutyrate, azobisisobutylamidine hydrochloride, 4,4′-azobis-4-cyanovaleric acid Initiators are mentioned.
These polymerization initiators may be used alone or in combination of two or more. The content of the polymerization initiator is 0.5 to 40 parts by weight, preferably 1 to 20 parts by weight with respect to 100 parts by weight of the total content having radical polymerizability.

<Other additives>
Furthermore, the cross-linked surface layer coating liquid of the present invention can be applied to various plasticizers (for the purpose of stress relaxation and adhesion improvement), leveling agents, low molecular charge transport materials having no radical reactivity, binder resins, etc. Additives can be included. As these additives, known additives can be used, and as plasticizers, those used in general resins such as dibutyl phthalate and dioctyl phthalate can be used, and the amount used is the total solid content of the coating liquid. To 20 wt% or less, preferably 10 wt% or less. As leveling agents, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain can be used, and the amount used depends on the total solid content of the coating liquid. 3% by weight or less is appropriate. Although the low molecular charge transport material is effective for improving the charge transport property of the crosslinked surface layer and lowering the exposed portion potential, the effect of high wear resistance is reduced because the addition of the curable material decreases. For this reason, the addition amount is adjusted by the process to be used, but it is used at 50% by weight or less, preferably 30% by weight or less, based on the total components of the crosslinked surface layer. The binder resin has the effect of reducing the internal stress of the crosslinked surface layer and increasing the uniformity, and suppressing the occurrence of cracks and scratches. However, since the effect of high wear resistance is reduced by addition as in the case of other additives, the amount added is suppressed to 20% by weight or less, preferably 10% by weight or less.

<Regarding coating solvent>
The crosslinked surface layer of the present invention is formed by applying and curing a coating solution containing at least a radical polymerizable compound containing the structural unit of the general formula (A) on the photosensitive layer described later. When the radically polymerizable compound is a liquid, such a coating liquid can be applied by dissolving other components in the liquid, but if necessary, it is diluted with a solvent and applied. Solvents used at this time include alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, tetrahydrofuran, dioxane and propyl ether. And ethers such as dichloromethane, dichloroethane, trichloroethane and chlorobenzene, aromatics such as benzene, toluene and xylene, cellosolves such as methyl cellosolve, ethyl cellosolve and cellosolve acetate. These solvents may be used alone or in combination of two or more. The dilution ratio with the solvent varies depending on the solubility of the composition, the coating method, and the target film thickness, and is arbitrary. The application can be performed by dip coating, spray coating, bead coating, ring coating, or the like.

In the present invention, after applying such a cross-linked surface layer coating solution, energy is applied from the outside and cured to form a cross-linked surface layer. The external energy used at this time is light, heat, or radiation. is there. As the energy of light, UV irradiation light sources such as high-pressure mercury lamps and metal halide lamps, which mainly have an emission wavelength in ultraviolet light, can be used, but a visible light source can also be selected according to the absorption wavelength of radically polymerizable substances and photopolymerization initiators. Is possible. Irradiation light amount is 50 mW / cm ² or more, preferably 1000 mW / cm ² or less, it takes time for the curing reaction is less than 50 mW / cm ^2. If it is higher than 1000 mW / cm ^2, the progress of the reaction becomes non-uniform, and local flaws are generated on the surface of the crosslinked surface layer, and many unreacted residues and reaction termination ends are generated. In addition, internal stress increases due to rapid crosslinking, which causes cracks and film peeling. The irradiation time depends on the UV light penetrability depending on the constituent material and the film thickness, but is preferably 5 seconds to 5 minutes. If it is too short, curing will be insufficient, and if it is too long, the constituent material will be decomposed and the electrical properties will deteriorate. In addition, it is desirable to control the temperature rise during curing to 50 ° C. or less to suppress decomposition of the constituent materials and uneven curing reaction.

When curing using thermal energy, 10 minutes to 3 hours are preferable at 100 to 170 ° C., and curing is insufficient at a temperature lower than 100 ° C. or a time shorter than 10 minutes. On the other hand, when the temperature is higher than 170 ° C. or longer than 3 hours, decomposition of the constituent materials and uneven curing reaction proceed, and a good crosslinked surface layer cannot be obtained.
An electron beam is preferably used as the energy of radiation. The acceleration voltage of the electron beam is 300 KV or less, preferably 150 KV or less, and the dose is cured under the conditions of 1 to 100 Mrad. When the acceleration voltage exceeds 300 KV or the dose exceeds 100 Mrad, the decomposition of the constituent materials proceeds, and the effect of the present invention is not exhibited.
Among these energies, those using light energy are useful because of the ease of reaction rate control and the simplicity of the apparatus.

Since the thickness of the crosslinked surface layer of the present invention varies depending on the structure of the underlying non-radical-cured photosensitive layer, it will be described later in accordance with the structure of the photosensitive layer.
Hereinafter, the present invention will be described according to the layer structure.

<About the layer structure of the electrophotographic photoreceptor>
The electrophotographic photosensitive member used in the present invention will be described with reference to the drawings.
1 and 2 are sectional views showing the electrophotographic photosensitive member of the present invention.
FIG. 1-A shows a case where a photosensitive layer having a charge generation function and a charge transport function at the same time is provided on a conductive support, and the crosslinked surface layer is the surface portion of the photosensitive layer. That is, the photosensitive layer that is not radically cured represents a photosensitive layer having the charge generation function and the charge transport function at the same time in the figure, and the crosslinked surface layer containing the radical curable composition represents the crosslinked surface layer in the figure. FIG. 1-B shows a single layer structure in which a charge generation layer having a charge generation function is provided as a photosensitive layer on a conductive support, and a crosslinked surface layer having a charge transporting compound is the surface portion of the photosensitive layer. Show the case. That is, the photosensitive layer that is not radically cured represents the charge generation layer in the figure, and the crosslinked surface layer containing the radical curable composition represents the crosslinked surface layer in the figure.
FIG. 2 shows a photoreceptor having a laminated structure in which a charge generation layer having a charge generation function and a charge transport layer having a charge transport material function are laminated as a photosensitive layer on a conductive support. The case where the cross-linked surface layer is the surface portion of the charge transport layer is shown. In other words, the photosensitive layer that is not subjected to LA · BR> W cal curing represents the charge generation layer and the charge transport layer in the figure, and the crosslinked surface layer containing the radical curable composition represents the crosslinked surface layer in the figure.

<About conductive support>
Examples of the conductive support include those having a volume resistance of 10 ¹⁰ Ω · cm or less, such as metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, and platinum, tin oxide, and indium oxide. After metal oxide is deposited or sputtered, film or cylindrical plastic, paper coated, or aluminum, aluminum alloy, nickel, stainless steel, etc. Pipes that have been subjected to surface treatment such as cutting, super-finishing, and polishing can be used. Further, endless nickel belts and endless stainless steel belts disclosed in JP-A-52-36016 can also be used as the conductive support.
In addition, those obtained by dispersing and coating conductive powder in an appropriate binder resin on the support can also be used as the conductive support of the present invention.

Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc and silver, or metal oxide powder such as conductive tin oxide and ITO. Can be mentioned. The binder resin used at the same time is polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. , Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, Examples thereof include thermoplastic, thermosetting resins, and photocurable resins such as melamine resin, urethane resin, phenol resin, and alkyd resin. Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.
Furthermore, it is electrically conductive by a heat-shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, and Teflon (registered trademark) on a suitable cylindrical substrate. Those provided with a conductive layer can also be used favorably as the conductive support of the present invention.

<About photosensitive layer>
Next, the photosensitive layer will be described. The photosensitive layer may have a laminated structure or a single layer structure.
In the case of a laminated structure, the photosensitive layer is composed of a charge generation layer having a charge generation function and a charge transport layer having a charge transport function. In the case of a single layer structure, the photosensitive layer is composed of a layer having a charge generation function and a charge transport function at the same time, or a charge generation layer having a charge generation function.
Hereinafter, each of the photosensitive layer having a laminated structure and the photosensitive layer having a single layer structure will be described.

<Photosensitive layer with a laminated structure>
(1) Charge generation layer The charge generation layer is a layer mainly composed of a charge generation material having a charge generation function, and a binder resin can be used in combination as necessary. As the charge generation material, inorganic materials and organic materials can be used.
Inorganic materials include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compounds, and amorphous silicon. In amorphous silicon, dangling bonds that are terminated with hydrogen atoms or halogen atoms, or those that are doped with boron atoms, phosphorus atoms, or the like are preferably used.
On the other hand, a known material can be used as the organic material. For example, phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, azulenium salt pigments, squaric acid methine pigments, azo pigments having a carbazole skeleton, azo pigments having a triphenylamine skeleton, azo pigments having a diphenylamine skeleton, dibenzothiophene skeleton Azo pigments having fluorenone skeleton, azo pigments having oxadiazole skeleton, azo pigments having bis-stilbene skeleton, azo pigments having distyryl oxadiazole skeleton, azo pigments having distyrylcarbazole skeleton, perylene Pigments, anthraquinone or polycyclic quinone pigments, quinoneimine pigments, diphenylmethane and triphenylmethane pigments, benzoquinone and naphthoquinone pigments, cyanine and azomethine pigments, Goido based pigments, and bisbenzimidazole pigments. These charge generation materials can be used alone or as a mixture of two or more.

  As a binder resin used as necessary for the charge generation layer, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, Examples include polyacrylamide. These binder resins can be used alone or as a mixture of two or more. In addition to the binder resin described above as a binder resin for the charge generation layer, a polymer charge transport material having a charge transport function, such as an arylamine skeleton, benzidine skeleton, hydrazone skeleton, carbazole skeleton, stilbene skeleton, pyrazoline skeleton, etc. Polymer materials such as polycarbonate, polyester, polyurethane, polyether, polysiloxane, and acrylic resin, polymer materials having a polysilane skeleton, and the like can be used.

  Specific examples of the former include JP-A-01-001728, JP-A-01-009964, JP-A-01-013061, JP-A-01-019049, JP-A-01-241559, Japanese Unexamined Patent Publication Nos. 04-011627, 04-175337, 04-183719, 04-2225014, 04-230767, 04-320420, 05 -232727, JP-A 05-310904, JP-A 06-234836, JP-A 06-234837, JP-A 06-234838, JP-A 06-234839, JP-A 06-234840. No. 1, JP-A 06-234841, JP-A 06-239049, Japanese Unexamined Patent Publication Nos. 06-236050, 06-236051, 06-295077, 07-0756374, 08-176293, 08-208820, 08 No. -21640, JP 08-253568, JP 08-269183, JP 09-062019, JP 09-043883, JP 09-71642, JP 09-87376. JP-A 09-104746, JP-A 09-110974, JP-A 09-110976, JP-A 09-157378, JP-A 09-221544, JP-A 09-227669. JP 09-235367 A, JP 09-241369 A Charge transporting polymer materials described in JP 09-268226 A, JP 09-272735 A, JP 09-302084 A, JP 09-302085 A, JP 09-328539 A, etc. Can be mentioned.

  Specific examples of the latter include polysilylene polymers described in, for example, JP-A No. 63-285552, JP-A No. 05-19497, JP-A No. 05-70595, JP-A No. 10-73944, and the like. Illustrated.

The charge generation layer may contain a low molecular charge transport material.
Low molecular charge transport materials that can be used in the charge generation layer include hole transport materials and electron transport materials.
Examples of the electron transporting material include chloroanil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide and diphenoquinone derivatives. These electron transport materials can be used alone or as a mixture of two or more.

  Examples of the hole transporting material include the electron donating materials shown below and are used favorably. As hole transport materials, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triaryls Other known materials such as methane derivatives, 9-styrylanthracene derivatives, pyrazoline derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, bisstilbene derivatives, enamine derivatives, and the like can be given. These hole transport materials can be used alone or as a mixture of two or more.

Methods for forming the charge generation layer include a vacuum thin film preparation method and a casting method from a solution dispersion system.
As the former method, a vacuum deposition method, a glow discharge decomposition method, an ion plating method, a sputtering method, a reactive sputtering method, a CVD method, or the like is used, and the above-described inorganic materials and organic materials can be satisfactorily formed.
In addition, in order to provide a charge generation layer by the casting method described later, if necessary, the inorganic or organic charge generation material together with a binder resin, tetrahydrofuran, dioxane, dioxolane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, cyclohexane. Can be formed by dispersing with a ball mill, attritor, sand mill, bead mill, etc. using a solvent such as pentanone, anisole, xylene, methyl ethyl ketone, acetone, ethyl acetate, butyl acetate, etc. . Moreover, leveling agents, such as a dimethyl silicone oil and a methylphenyl silicone oil, can be added as needed. The application can be performed by dip coating, spray coating, bead coating, ring coating, or the like.
The thickness of the charge generation layer provided as described above is suitably about 0.01 to 5 μm, preferably 0.05 to 2 μm.

(2) Charge Transport Layer The charge transport layer is formed by dissolving or dispersing a charge transport material having a charge transport function and a binder resin in a suitable solvent, and applying and drying the solution on the charge generation layer.
As the charge transport material, the electron transport material, hole transport material and polymer charge transport material described in the charge generation layer can be used. In particular, the use of a polymer charge transport material is particularly useful because it has an effect of reducing the solubility of the lower layer during coating of the crosslinked surface layer.
Examples of the binder resin include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, Polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin And thermoplastic resins such as phenol resins and alkyd resins.
The amount of the charge transport material is appropriately 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. However, when a polymer charge transport material is used, it can be used alone or in combination with a binder resin.

As the solvent used for coating the charge transport layer, the same solvent as that used for the charge generation layer can be used, but a solvent that dissolves the charge transport material and the binder resin well is suitable. These solvents may be used alone or in combination of two or more. The charge transport layer can be formed by the same coating method as that for the charge generation layer.
If necessary, a plasticizer and a leveling agent can be added.
As the plasticizer that can be used in combination with the charge transport layer, those generally used as resin plasticizers such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is based on 100 parts by weight of the binder resin. About 0 to 30 parts by weight is appropriate.
Leveling agents that can be used in combination with the charge transport layer include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain. The amount used is a binder resin. About 0 to 1 part by weight is appropriate for 100 parts by weight.
The thickness of the charge transport layer is suitably about 5 to 40 μm, preferably about 10 to 30 μm.

(3) About the crosslinked surface layer As described in the above-mentioned crosslinked surface layer preparation method, the crosslinked surface layer is coated with the crosslinked surface layer coating liquid of the present invention on the charge transport layer and, if necessary, dried. Then, the curing reaction is initiated by the energy of light, heat or radiation to form a crosslinked surface layer. In the case where the photosensitive layer is a laminated structure, the crosslinked surface layer contains a charge transporting compound (regardless of having or not having a radical polymerizable functional group) and imparting a charge transporting function, It is good also as a protective layer, without containing. At this time, the film thickness of the cross-linked surface layer is 1 μm or more and 15 μm or less, more preferably 2 μm or more and 13 μm or less when the charge transport function is imparted. When it is thicker than 15 μm, cracks and film peeling tend to occur. When it is used as a protective layer without imparting a charge transport function, the crosslink density can be further increased and the wear resistance can be enhanced. In this case, the film thickness of the crosslinked surface layer is 1 μm or more and 5 μm or less, more preferably 2 μm or more and 4 μm or less. If it is thicker than 5 μm, cracks and film peeling are likely to occur as described above, and a significant decrease in sensitivity occurs due to lack of charge transport capability. When the film thickness of the cross-linked surface layer is less than 1 μm, the durability varies due to film thickness unevenness. (By using at 2 μm or more and 4 μm or less, there is an excellent effect that cracks, film peeling, and sensitivity reduction are less likely to occur.)

<Single photosensitive layer>
The photosensitive layer having a single layer structure is a layer having a charge generation function and a charge transport function at the same time, or a charge generation layer having a charge generation function.
(1) In the case of a single layer structure having both a charge generation function and a charge transport function When the photosensitive layer is a layer having both a charge generation function and a charge transport function, the photosensitive layer has a charge generation function and a charge transport function. It can be formed by dissolving or dispersing a charge transport material having a function and a binder resin in an appropriate solvent, and applying and drying the solution. Moreover, a plasticizer, a leveling agent, etc. can also be added as needed. As the charge generation material dispersion method, the charge generation material, the charge transport material, the plasticizer, and the leveling agent may be the same as those already described in the charge generation layer and the charge transport layer. As the binder resin, in addition to the binder resin previously mentioned in the section of the charge transport layer, the binder resin mentioned in the charge generation layer may be mixed and used. In addition, the polymer charge transport materials listed above can also be used, which is useful in that the mixing of the photosensitive layer composition into the crosslinked surface layer can be reduced. The charge generation material contained in the photosensitive layer is preferably 1 to 30% by weight based on the total amount of the photosensitive layer, the binder resin contained in the photosensitive layer is 20 to 80% by weight, and the charge transport material is 10 to 70% by weight. Part is used well.
The film thickness of the photosensitive layer is 5 to 30 μm, preferably 10 to 25 μm.

  When the cross-linked surface layer is the surface portion of the photosensitive layer having the above single layer structure, the cross-linked surface layer coating solution of the present invention is applied onto the photosensitive layer as described above, and if necessary, dried, light, heat or Cured by the energy of radiation to form a crosslinked surface layer. When the photosensitive layer has the single layer structure, the crosslinked surface layer contains a charge transporting compound (regardless of having or not having a radical polymerizable functional group) and imparting a charge transporting function. However, it is good also as a protective layer, without containing. At this time, the film thickness of the cross-linked surface layer is 1 μm or more and 15 μm or less, more preferably 2 μm or more and 13 μm or less when the charge transport function is imparted. When it is thicker than 15 μm, cracks and film peeling tend to occur. When it is used as a protective layer without imparting a charge transport function, the crosslink density can be further increased, and the wear resistance can be enhanced. In this case, the thickness of the crosslinked surface layer is 1 μm or more and 5 μm or less, more preferably 2 μm or more and 4 μm or less. When it is thicker than 5 μm, cracks and film peeling tend to occur as described above. Moreover, since there is no charge transport capability, a significant reduction in sensitivity occurs. When the film thickness of the cross-linked surface layer is less than 1 μm, durability varies due to film thickness unevenness.

(2) In the case of a single-layer structure of a charge generation layer having a charge generation function When the photosensitive layer is a charge generation layer having a charge generation function, the charge generation layer has the same structure as the charge generation layer raised in the laminated structure. Things can be used. The cross-linked surface layer provided on the charge generation layer contains a charge transporting compound in order to have a charge transporting function. At this time, the charge transporting compound may or may not have a radical polymerizable functional group. However, when a compound having a radical polymerizable functional group is used as the charge transporting compound, the high wear resistance effect of the present invention can be exhibited more excellently, which is preferable. The cross-linked surface layer having a charge transport function is applied with the cross-linked surface layer coating solution of the present invention on the charge generation layer as described in the preparation method, and after drying, if necessary, light, heat, or radiation energy. By this, the curing reaction is started and a crosslinked surface layer is formed. At this time, the film thickness of the crosslinked surface layer is 10 to 30 μm, preferably 10 to 25 μm. If it is thinner than 10 μm, a sufficient charging potential cannot be maintained, and if it is thicker than 30 μm, peeling from the lower layer tends to occur due to volume shrinkage during curing.

<About the intermediate layer>
In the photoreceptor of the present invention, when the crosslinked surface layer becomes the surface portion of the photosensitive layer, an intermediate layer can be provided between the crosslinked surface layer and the photosensitive layer. This intermediate layer prevents inhibition of the curing reaction and unevenness of the crosslinked surface layer caused by mixing of the photosensitive layer composition that is not radically cured in the crosslinked surface layer containing the radical curable composition. It is also possible to improve the adhesion between the photosensitive layer and the crosslinked surface layer.
In the intermediate layer, a binder resin is generally used as a main component. Examples of these resins include polyamide, alcohol-soluble nylon, water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol. As a method for forming the intermediate layer, a generally used coating method is employed as described above. In addition, about 0.05-2 micrometers is suitable for the thickness of an intermediate | middle layer.

<About the undercoat layer>
In the photoreceptor of the present invention, an undercoat layer can be provided between the conductive support and the photosensitive layer. In general, the undercoat layer is mainly composed of a resin. However, considering that the photosensitive layer is coated with a solvent on these resins, the resin may be a resin having high solvent resistance with respect to a general organic solvent. desirable. Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. Further, a metal oxide fine powder pigment exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like may be added to the undercoat layer in order to prevent moire and reduce residual potential.

These undercoat layers can be formed using an appropriate solvent and a coating method like the above-mentioned photosensitive layer. Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the undercoat layer of the present invention. In addition, in the undercoat layer of the present invention, Al ₂ O ₃ is provided by anodic oxidation, organic substances such as polyparaxylylene (parylene), SiO ₂ , SnO ₂ , TiO ₂ , ITO, CeO ₂ A material provided with an inorganic material such as a vacuum thin film can also be used favorably. In addition, known ones can be used. The thickness of the undercoat layer is suitably from 0 to 5 μm.

<Addition of antioxidant to each layer>
Further, in the present invention, in order to improve environmental resistance, in order to prevent a decrease in sensitivity and an increase in residual potential, in particular, a crosslinked surface layer, a charge generation layer, a charge transport layer, an undercoat layer, an intermediate layer, etc. Antioxidants can be added to each layer.
The following are mentioned as antioxidant which can be used for this invention.
(Phenolic compounds)
2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3,5-di-t-butyl-4 -Hydroxyphenyl) propionate, 2,2'-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2'-methylene-bis- (4-ethyl-6-tert-butylphenol), 4, 4'-thiobis- (3-methyl-6-tert-butylphenol), 4,4'-butylidenebis- (3-methyl-6-tert-butylphenol), 1,1,3-tris- (2-methyl-4 -Hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene- -(3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3'-bis (4'-hydroxy-3'-t-butylphenyl) butyric acid ] Cryol ester, tocopherols and the like.

(Paraphenylenediamines)
N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N'- Di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine and the like.
(Hydroquinones)
2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2-octadecenyl) ) -5-methylhydroquinone and the like.

(Organic sulfur compounds)
Dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, penta Erythritol tetrakis (3-laurylthio-propionate) and the like.
(Organic phosphorus compounds)
Triphenyl phosphite, tris (nonylphenyl) phosphite, tri (dinonylphenyl) phosphite, tris (2-ethylhexyl) phosphite, tridecyl phosphite, tris (tridecyl) phosphite, diphenyl mono (2-ethylhexyl) Phosphite, diphenyl monodecyl phosphite, tris (2,4, di-t-butylphenyl) phosphite, distearyl pentaerythritol diphosphite, bis (2,4, di-t-butylphenyl) pentaerythritol phosphite, 2 , 2-methylenebis (4,6-di-t-butylphenyl) octyl phosphite, tetrakis (2,4-di-t-butylphenyl) 4,4′-biphenylene-diphosphonite, dilauryl hydrogen phosphite, diphenyl Hydrogen phosphite, tetraphenyldipropylene glycol diphosphite, tetraphenyltetra (tridecyl) pentaerythritol tetraphosphite, tetra (tridecyl) -4,4′isopropylidene diphenyldiphosphite, bis (nonylphenyl) pentaerythritol diphos Phyto, hydrogenated bisphenol A, pentaerythritol phosphite polymer, etc.
These compounds are known as antioxidants such as rubbers, plastics and fats and oils, and commercially available products can be easily obtained.
The addition amount of the antioxidant in the present invention is 0.01 to 10% by weight based on the total weight of the layer to be added.

<Image Forming Method and Apparatus>
Next, the image forming method and the image forming apparatus of the present invention will be described in detail with reference to the drawings.
The image forming method and the image forming apparatus of the present invention use a photoconductor having a non-radical-cured photosensitive layer of the present invention and a crosslinked surface layer containing a specific radical-curing composition. An image forming method and an image forming apparatus comprising processes of image exposure and development, followed by a process of transferring a toner image onto an image carrier (transfer paper), fixing, and cleaning of the surface of the photoreceptor.
In some cases, an image forming method or the like in which an electrostatic latent image is directly transferred to a transfer member and developed does not necessarily have the above-described process arranged on the photosensitive member.

FIG. 3 is a schematic diagram illustrating an example of an image forming apparatus. A charging charger (3) is used as a means for charging the photoconductor on average. As the charging means, a corotron device, a scorotron device, a solid discharge element, a needle electrode device, a roller charging device, a conductive brush device, or the like is used, and a known method can be used.
Next, the image exposure unit (5) is used to form an electrostatic latent image on the uniformly charged photoreceptor (1). As the light source, all luminescent materials such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL) can be used. Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.

Next, the developing unit (6) is used to visualize the electrostatic latent image formed on the photoreceptor (1). Development methods include a one-component development method using a dry toner, a two-component development method, and a wet development method using a wet toner. When the photosensitive member is positively (negatively) charged and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. A positive image can be obtained by developing this with negative (positive) toner (electrodetection fine particles), and a negative image can be obtained by developing with positive (negative) toner.
Next, a transfer charger (10) is used to transfer the toner image visualized on the photoconductor onto the transfer body (9). In addition, a pre-transfer charger (7) may be used for better transfer. As these transfer means, a transfer charger, an electrostatic transfer method using a bias roller, a mechanical transfer method such as an adhesive transfer method and a pressure transfer method, and a magnetic transfer method can be used. As the electrostatic transfer method, the charging means can be used.

Next, a separation charger (11) and a separation claw (12) are used as means for separating the transfer body (9) from the photoreceptor (1). As other separation means, electrostatic adsorption induction separation, side end belt separation, tip grip conveyance, curvature separation, and the like are used. As the separation charger (11), the charging means can be used.
Next, a fur brush (14) and a cleaning blade (15) are used to clean the toner remaining on the photoreceptor after transfer. Further, a pre-cleaning charger (13) may be used in order to perform cleaning more efficiently. As other cleaning means, there are a web system, a magnet brush system, and the like, but a single system or a plurality of systems may be used together.

Next, a neutralizing unit is used for the purpose of removing the latent image on the photoconductor as necessary. As the charge removal means, a charge removal lamp (2) and a charge removal charger are used, and the exposure light source and the charging means can be used respectively.
In addition, known processes can be used for reading, feeding, fixing, paper discharge and the like that are not close to the photoconductor.

The present invention is an image forming method and an image forming apparatus using the electrophotographic photoreceptor according to the present invention for such image forming means.
This image forming means may be fixedly incorporated in a copying apparatus, facsimile, or printer, but may be incorporated in these apparatuses in the form of a process cartridge and detachable. An example of the process cartridge is shown in FIG.
The process cartridge for the image forming apparatus includes a photoreceptor (101), and in addition, a charging unit (102), a developing unit (104), a transfer unit (106), a cleaning unit (107), and a discharging unit (not shown). ), And an apparatus (part) that can be attached to and detached from the image forming apparatus main body.

  Referring to the image forming process by the apparatus illustrated in FIG. 4, the surface of the photoreceptor (101) is exposed by charging by the charging means (102) and exposure by the exposure means (103) while rotating in the direction of the arrow. An electrostatic latent image corresponding to the image is formed, and the electrostatic latent image is developed with toner by the developing means (104). The toner development is transferred to the transfer body (105) by the transfer means (106), and printed. Be out. Next, the surface of the photoconductor after the image transfer is cleaned by a cleaning unit (107), and is further neutralized by a neutralizing unit (not shown), and the above operation is repeated again.

The present invention relates to an electrophotographic photosensitive member according to the present invention having a photosensitive layer that is not radically cured and a cross-linked surface layer containing a specific radical curing composition, and at least one of charging, developing, transferring, cleaning, and neutralizing means. Is provided as a process cartridge for an image forming apparatus.
As is apparent from the above description, the electrophotographic photosensitive member of the present invention is not only used in electrophotographic copying machines, but also in electrophotographic application fields such as laser beam printers, CRT printers, LED printers, liquid crystal printers, and laser plate making. Can also be used widely.

<Synthesis Example 1 of Radical Polymerizable Compound Represented by General Formula (B) Used in the Present Invention>
(1) Synthesis of B-1-1
6 g (0.0224 mol) of 1,1-Bis (4-hydroxyphenyl) cyclohexane (Tokyo Kasei B1568) is dissolved in 70 ml of tetrahydrofuran, and an aqueous sodium hydroxide solution (NaOH: 3.76 g, water: 32 ml) in a nitrogen stream. It was dripped. The solution was cooled to 2 ° C., and 8.26 g (0.0456 mol) of acrylic acid chloride was added dropwise over 30 minutes. Then, it stirred at 2-5 degreeC for 5 hours, and complete | finished reaction. The reaction solution was poured into water to precipitate a white powdery coarse product, which was filtered and washed repeatedly with water. Thereafter, this crude product is subjected to column chromatography (adsorption medium: silica gel, developing solvent: toluene / ethyl acetate (10/1)), and then recrystallized with ethanol to obtain the desired product (Exemplary Compound B-1-1). ) White crystals (4.99 g) (yield = 59.3%). The melting point and elemental analysis value of the obtained compound are shown below. An infrared absorption spectrum (KBr method) is shown in FIG.
Melting point: 117.5-118.0 ° C
Elemental analysis value (%)
C (%) H (%) N (%)
Actual value 76.65 6.40 0.00
Calculated value 76.57 6.43 0.00

<Synthesis Example 2 of Radical Polymerizable Compound Represented by General Formula (B) Used in the Present Invention>
(1) Synthesis of B-2-4
Dissolve 9,9-Bis [4- (2-hydroxyethoxy) phenyl] fluorene (Tokyo Kasei F0447) 6g (0.0137 mol) in 70 ml dimethylacetamide, 6.95 g 3-chloropropionyl chloride at 3 ° C. in a nitrogen stream. (0.0548 mol) was added dropwise and stirred at room temperature for 3.5 hours. Thereafter, 11.08 g of triethylamine was added dropwise at room temperature in a nitrogen stream over 40 minutes, followed by stirring at 60 ° C. for 4 hours to complete the reaction. The reaction solution was poured into water, extracted with ethyl acetate, and the extract was washed repeatedly with water. Thereafter, the solvent was removed from the extract and purified by column chromatography (adsorption medium: silica gel, developing solvent: toluene / ethyl acetate (3/1)). In this way, 6.18 g (yield = 82.6%) of Illustrative Compound B-2-4 as a colorless transparent oil was obtained. Elemental analysis values of the obtained compound are shown below. Further, an infrared absorption spectrum (NaCl plate coating) is shown in FIG.
Elemental analysis value (%)
C (%) H (%) N (%)
Actual value 76.70 6.51 0.00
Calculated value 76.91 5.53 0.00

<Synthesis Example 1 of Radical Polymerizable Compound Represented by General Formula (C) Used in the Present Invention>
(1) Synthesis of intermediate compound A having the following structure
1,1-Bis (4-hydroxyphenyl) cyclohexane (Tokyo Kasei B1568) 9.83 g (0.0366 mol) and glycidyl methacrylate 12.06 g (0.0806 mol) were dissolved in toluene 50 ml, triethylamine 0.3 ml was added, The mixture was stirred at 95 ° C. for 9 hours in an argon stream. Thereafter, 37 ml of a 10% by weight aqueous sodium hydroxide solution and 30 ml of toluene were added at room temperature, followed by stirring at 92 ° C. for 6 hours to complete the reaction. The reaction solution was neutralized with hydrochloric acid, and the precipitated crystals were separated by filtration and washed with water. Furthermore, it was purified by column chromatography (adsorption medium: silica gel, developing solvent: ethyl acetate / THF (1/1)). In this way, 9.16 g (yield = 60.1%) of colorless powdery intermediate A was obtained. An infrared absorption spectrum of the obtained intermediate A is shown in FIG.

(2) Synthesis of C-1-1 9.16 g (0.0220 mol) of the intermediate compound A was dissolved in 87 ml of dimethylacetamide. 16.75 g (0.132 mol) of 3-chloropropionyl chloride was added at 3 ° C. in an argon stream and stirred at room temperature for 7 hours. Thereafter, 37 ml of triethylamine was added at 3 ° C., and the mixture was stirred at 60 ° C. for 5 hours to complete the reaction. The reaction solution was poured into water, extracted with dichloromethane, and the extract was washed repeatedly with water. Thereafter, the solvent was removed from the extract and purified by column chromatography (adsorption medium: silica gel, developing solvent: n-hexane / ethyl acetate (2/1)). In this way, 11.9 g (yield from intermediate = 85.5%) of oily exemplary compound C-1-1 was obtained. The infrared absorption spectrum of the obtained exemplary compound C-1-1 is shown in FIG.
As described above, other diphenol compounds can be synthesized in the same manner.

<Synthesis Example 1 of Radical Polymerizable Compound Represented by General Formula (D) Used in the Present Invention>
(1) Synthesis of D-1-4 In a reaction vessel equipped with a stirrer, a thermometer, and a dropping funnel, 5.93 g (0.020 mol) of 1,1-Bis (4-hydroxy-3-methylphenyl) cyclohexane and epichlorohydrin 18.51 g (200 mmol) and 20 ml of toluene were added, and the mixture was heated and stirred at 110 ° C. in a nitrogen stream.
To this, 9.60 g (48 mmol) of a 20 wt% aqueous sodium hydroxide solution was added dropwise over 30 minutes so that the temperature in the reaction system was maintained at 100 ° C. to 120 ° C., and reacted at 110 ° C. for 4 hours. This was allowed to cool to room temperature, and excess epichlorohydrin was recovered under reduced pressure, and then toluene was added to wash the organic layer with water. The toluene solution was dried over anhydrous magnesium sulfate and concentrated under reduced pressure. This liquid was subjected to column chromatography (adsorption medium: silica gel, developing solvent: toluene / ethyl acetate (1/1)) to remove the raw materials and high molecular weight components. As a result, 6.92 g of a colorless transparent oily substance was obtained.
The oily substance was dissolved again in 80 ml of toluene, put into a reaction vessel together with 2.88 g (0.040 mol) of acrylic acid and 0.2 ml of triethylamine, and reacted at 80 ° C. for 3 hours. The mixture was allowed to cool, washed with water, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. This was again made into a toluene solution, 5 g of activated clay was added, and the mixture was subjected to adsorption treatment at room temperature for 30 minutes, followed by column chromatography (adsorption medium: silica gel, developing solvent: toluene / ethyl acetate (3/1)), and unreacted. The product and high molecular weight components were removed. As a result, 6.53 g of a colorless transparent oily substance (D-1-4) was obtained.
When the molecular weight of this product was measured by gel permeation chromatography, it showed a value which is a composition mainly composed of a mixture of n = 1-5.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to a following example. Note that “parts” used in the examples all represent parts by weight.

<Example 1>
A photosensitive layer coating solution having the following composition was applied on a φ30 mm aluminum cylinder by a dipping method to form a photosensitive layer having a thickness of 23 μm after drying. After the photosensitive layer of the crosslinked surface layer coating liquid having the following composition was spray coated on, and naturally dried for 5 minutes, a metal halide lamp: 160 W / cm, irradiation distance: 120 mm, irradiation intensity: 800 mW / cm ^2, irradiation time: The coating film was cured by light irradiation under conditions of 60 seconds. Further, drying was performed at 130 ° C. for 20 minutes to provide a 2 μm cross-linked surface layer to obtain the electrophotographic photosensitive member of the present invention.

[Photosensitive layer coating solution]
In the following formulation, a 3% solid content solution of metal-free phthalocyanine and tetrahydrofuran was ball milled with zirconia balls for 24 hours. The prepared pigment dispersion was added to a solution in which the remaining materials were mixed and dissolved to prepare a coating solution.
・ Metal-free phthalocyanine: 2 parts (FastogenBlue8120B, manufactured by Dainippon Ink & Chemicals, Inc.)
-Charge transport material of the following structural formula: 24 parts
・ The following diphenoquinone compound: 20 parts
2,6-Dimethyl-2 ', 6'-di-tert-butyl-diphenoquinone Bisphenol Z-type polycarbonate: 41 parts
(Panlite TS-2050, manufactured by Teijin Chemicals)
Tetrahydrofuran: 382 parts Tetrahydrofuran solution of 1% silicone oil: 0.2 parts (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

[Crosslinked surface layer coating solution]
In the following formulation, all materials were mixed and dissolved in a dark place to prepare a coating solution.
-Radical polymerizable compound of Exemplified Compound B-2-4: 20 parts-Photopolymerization initiator: 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 2>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the crosslinked surface layer coating solution of Example 1 was changed to the following and the thickness of the crosslinked surface layer was changed to 5 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of Exemplified Compound B-2-4: 10 parts-Charge transporting compound having one or more radical polymerizable functional groups: 10 parts (Exemplary Compound NO. 54)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 3>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the crosslinked surface layer coating solution of Example 1 was changed to the following.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of exemplary compound C-1-1: 20 parts-Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 4>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the crosslinked surface layer coating solution of Example 1 was changed to the following and the thickness of the crosslinked surface layer was changed to 5 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of exemplary compound C-1-1: 10 parts-Charge transporting compound having one or more radical polymerizable functional groups: 10 parts (Exemplary compound NO. 54)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 5>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the crosslinked surface layer coating solution of Example 1 was changed to the following.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of Exemplified Compound D-1-4: 20 parts-Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 6>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the crosslinked surface layer coating solution of Example 1 was changed to the following and the thickness of the crosslinked surface layer was changed to 5 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of exemplary compound D-1-4: 10 parts-Charge transporting compound having one or more radical polymerizable functional groups: 10 parts (Exemplary compound NO. 54)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 7>
By coating and drying an undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution in the following order on a φ30 mm aluminum cylinder in sequence, an undercoat layer of 3.5 μm A 0.2 μm charge generation layer and an 18 μm charge transport layer were formed. On this charge transport layer, a cross-linked surface layer coating solution having the following composition is spray-coated, and after natural drying for 5 minutes, a metal halide lamp: 160 W / cm, irradiation distance: 120 mm, irradiation intensity: 800 mW / cm ² , irradiation time : Light irradiation was performed under the condition of 60 seconds to cure the coating film. Further, drying was performed at 130 ° C. for 20 minutes to provide a 3 μm cross-linked surface layer to obtain the electrophotographic photosensitive member of the present invention.

[Undercoat layer coating solution]
In the following formulation, all materials were mixed and ball milled with alumina balls for 48 hours. This dispersion was filtered through a 500 mesh stainless steel mesh to prepare a coating solution.
・ Alkyd resin: 6 parts (Beckolite M-6401-50, manufactured by Dainippon Ink & Chemicals, Inc.)
Melamine resin: 4 parts (Super Becamine G-821-60, manufactured by Dainippon Ink and Chemicals)
・ Titanium oxide: 40 parts ・ Methyl ethyl ketone: 50 parts

[Coating liquid for charge generation layer]
In the following formulation, a 10% solid content solution of bisazo pigment and methyl ethyl ketone was ball milled with zirconia balls for 10 days. Cyclohexanone was added to this dispersion to obtain a pigment dispersion having a solid content of 3%, followed by ball mill dispersion for 2 hours. This pigment dispersion was added to a solution in which the remaining materials were mixed and dissolved, and stirred well, and then filtered through a 1000 mesh stainless steel mesh to prepare a coating solution.
-Bisazo pigment with the following structure: 2.5 parts
Polyvinyl butyral (XYHL, manufactured by UCC): 0.5 part Cyclohexanone: 200 parts Methyl ethyl ketone: 80 parts

[Coating fluid for charge transport layer]
In the following formulation, all materials were mixed and dissolved to prepare a coating solution.
-Bisphenol Z-type polycarbonate: 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
-Charge transport material with the following structural formula: 7 parts
Tetrahydrofuran: 100 parts Tetrahydrofuran solution of 1% silicone oil: 1 part (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

[Crosslinked surface layer coating solution]
In the following formulation, all materials were mixed and dissolved in a dark place to prepare a coating solution.
-Radical polymerizable compound of Exemplified Compound B-2-4: 20 parts-Photopolymerization initiator: 1 part 1-Hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 8>
An electrophotographic photosensitive member was produced in the same manner as in Example 7, except that the crosslinked surface layer coating solution of Example 7 was changed to the following.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of exemplary compound C-1-1: 20 parts-Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 9>
An electrophotographic photosensitive member was produced in the same manner as in Example 7, except that the crosslinked surface layer coating solution of Example 7 was changed to the following.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of Exemplified Compound D-1-4: 20 parts-Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 10>
An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the crosslinked surface layer coating solution of Example 7 was changed to the following and the thickness of the crosslinked surface layer was changed to 7 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of exemplary compound B-1-1: 5 parts-Monomer having 3 or more radical polymerizable functional groups: 5 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku)
-Charge transporting compound having one or more radically polymerizable functional groups: 10 parts (Exemplary Compound NO. 54)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 11>
An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the crosslinked surface layer coating solution of Example 7 was changed to the following and the thickness of the crosslinked surface layer was changed to 7 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of Exemplified Compound B-1-5: 5 parts Exemplified Compound B-1-5 is 9,9-Bis (4-hydroxy-3-methylphenyl) fluorene (manufactured by Tokyo Chemical Industry)
Diacrylate compound synthesized in the same manner as B-1-1 Synthesis Example 1 from B2396) Monomer having three or more radical polymerizable functional groups: 5 parts Dipentaerythritol caprolactone-modified hexaacrylate (KAYARAD DPCA-120, Japan Kayaku)
-Charge transporting compound having one or more radically polymerizable functional groups: 10 parts (Exemplary Compound NO. 54)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 12>
An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the crosslinked surface layer coating solution of Example 7 was changed to the following and the thickness of the crosslinked surface layer was changed to 7 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of Exemplified Compound B-1-7: 5 parts Exemplified Compound B-1-7 is obtained from 1,1-Bis (3-cyclohexyl-4-hydroxyphenyl) cyclohexane (Tokyo Kasei B2752) to B-1- 1 Diacrylate synthesized in the same manner as in Synthesis Example 1. Monomer having 3 or more radical polymerizable functional groups: 5 parts Dipentaerythritol caprolactone-modified hexaacrylate (KAYARAD DPCA-120, Nippon Kayaku)
-Charge transporting compound having one or more radical polymerizable functional groups: 10 parts (Exemplary Compound NO. 109)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 13>
An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the crosslinked surface layer coating solution of Example 7 was changed to the following and the thickness of the crosslinked surface layer was changed to 7 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of Exemplified Compound B-1-10: 5 parts Exemplified Compound B-1-10 was converted from diphenol BisP-PZ (Honshu Chemical) to B-
1-1 Diacrylate synthesized in the same manner as in Synthesis Example 1. Monomer having 3 or more radical polymerizable functional groups: 5 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku)
-Charge transporting compound having one or more radically polymerizable functional groups: 10 parts (Exemplary Compound NO. 54)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 14>
An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the crosslinked surface layer coating solution of Example 7 was changed to the following and the thickness of the crosslinked surface layer was changed to 7 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of Exemplified Compound B-1-12: 5 parts Exemplified Compound B-1-12 was synthesized in the same manner as B-1-1 Synthesis Example 1 using methacrylic acid chloride instead of acrylic acid chloride. Dimethacrylates ・ Monomers with 3 or more radical polymerizable functional groups: 5 parts Dipentaerythritol hexaacrylate (KAYARAD DPHA, Nippon Kayaku)
-Charge transporting compound having one or more radical polymerizable functional groups: 10 parts (Exemplary Compound NO. 147)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 15>
An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the crosslinked surface layer coating solution of Example 7 was changed to the following and the thickness of the crosslinked surface layer was changed to 7 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of Exemplified Compound B-2-4: 10 parts-Charge transporting compound having one or more radical polymerizable functional groups: 10 parts (Exemplary Compound NO. 54)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 16>
An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the crosslinked surface layer coating solution of Example 7 was changed to the following and the thickness of the crosslinked surface layer was changed to 7 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of exemplary compound C-1-1: 10 parts-Charge transporting compound having one or more radical polymerizable functional groups: 10 parts (Exemplary compound NO. 54)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 17>
An electrophotographic photosensitive member was prepared in the same manner as in Example 7 except that the crosslinked surface layer coating solution of Example 7 was changed to the following and the film thickness was changed to 7 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of Exemplified Compound C-1-11: 5 parts Exemplified Compound C-1-11 is glycidyl methacrylate from 9,9-Bis (4-hydroxy-3-methylphenyl) fluorene (B2396, Tokyo Chemical Industry). Dimethacrylate derivative derived from dimethacrylate in step C1-1 used, and further synthesized with 3-chloropropionyl chloride. Monomer having three or more radical polymerizable functional groups: 5 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku)
-Charge transporting compound having one or more radically polymerizable functional groups: 10 parts (Exemplary Compound NO. 54)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 18>
An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the crosslinked surface layer coating solution of Example 7 was changed to the following and the thickness of the crosslinked surface layer was changed to 7 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of Exemplified Compound D-1-1: 10 parts Exemplified Compound D-1-1 increases the amount of epichlorohydrin of D-1-4 Synthesis Example 1,
A diacrylate compound synthesized in the same manner as D-1-4. Charge transporting compound having one or more radically polymerizable functional groups: 10 parts (Exemplary Compound NO. 54)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Example 19>
An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the crosslinked surface layer coating solution of Example 7 was changed to the following and the thickness of the crosslinked surface layer was changed to 7 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of exemplary compound D-1-4: 5 parts-Monomer having 3 or more radical polymerizable functional groups: 5 parts Dipentaerythritol hexaacrylate (KAYARAD DPHA, Nippon Kayaku)
-Charge transporting compound having one or more radically polymerizable functional groups: 10 parts (Exemplary Compound NO. 54)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Comparative Example 1>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the crosslinked surface layer coating solution of Example 1 was changed to the following.
[Crosslinked surface layer coating solution]
-Radical polymerizable monomer having the following structural formula: 20 parts
Bisphenol A ethyleneoxy modified diacrylate (ABE-300, Shin-Nakamura Chemical Co., Ltd.)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Comparative example 2>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the crosslinked surface layer coating solution of Example 1 was changed to the following and the thickness of the crosslinked surface layer was changed to 5 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable monomer: 10 parts Bisphenol A ethyleneoxy modified diacrylate (ABE-300, Shin-Nakamura Chemical Co., Ltd.)
-Charge transporting compound having one or more radically polymerizable functional groups: 10 parts (Exemplary Compound NO. 54)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Comparative Example 3>
An electrophotographic photosensitive member was produced in the same manner as in Example 7, except that the crosslinked surface layer coating solution of Example 7 was changed to the following.
[Crosslinked surface layer coating solution]
-Radical polymerizable monomer: 20 parts Bisphenol A ethyleneoxy modified diacrylate (ABE-300, Shin-Nakamura Chemical Co., Ltd.)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Comparative Example 4>
An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the crosslinked surface layer coating solution of Example 7 was changed to the following and the thickness of the crosslinked surface layer was changed to 7 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable monomer: 10 parts Bisphenol A ethyleneoxy modified diacrylate (ABE-300, Shin-Nakamura Chemical Co., Ltd.)
-Charge transporting compound having one or more radically polymerizable functional groups: 10 parts (Exemplary Compound NO. 54)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Comparative Example 5>
An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the crosslinked surface layer coating solution of Example 7 was changed to the following and the thickness of the crosslinked surface layer was changed to 7 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable monomer: 5 parts Bisphenol A ethyleneoxy modified diacrylate (ABE-300, Shin-Nakamura Chemical Co., Ltd.)
・ Monomer having 3 or more radical polymerizable functional groups: 5 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, Nippon Kayaku)
-Charge transporting compound having one or more radically polymerizable functional groups: 10 parts (Exemplary Compound NO. 54)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Comparative Example 6>
An electrophotographic photosensitive member was produced in the same manner as in Example 7, except that the crosslinked surface layer coating solution of Example 7 was changed to the following.
[Crosslinked surface layer coating solution]
・ Radically polymerizable monomer: 20 parts Dipentaerythritol hexaacrylate (KAYARAD DPHA, Nippon Kayaku)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Comparative Example 7>
An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the crosslinked surface layer coating solution of Example 7 was changed to the following and the thickness of the crosslinked surface layer was changed to 7 μm.
[Crosslinked surface layer coating solution]
・ Radically polymerizable monomer: 10 parts Dipentaerythritol hexaacrylate (KAYARAD DPHA, Nippon Kayaku)
-Charge transporting compound having one or more radically polymerizable functional groups: 10 parts (Exemplary Compound NO. 54)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Comparative Example 8>
An electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the crosslinked surface layer coating solution of Example 7 was changed to the following and the thickness of the crosslinked surface layer was changed to 7 μm.
[Crosslinked surface layer coating solution]
・ Radically polymerizable monomer of the following structural formula: 5 parts Neopentyl glycol diacrylate (KAYARAD NPGDA, Nippon Kayaku)
-Charge transporting compound having one or more radically polymerizable functional groups: 10 parts (Exemplary Compound NO. 54)
Photopolymerization initiator: 1 part 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Tetrahydrofuran: 100 parts

<Comparative Example 9>
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the crosslinked surface layer of Example 1 was not provided and the film thickness of the photosensitive layer was 28 μm.
<Comparative Example 10>
An electrophotographic photosensitive member was produced in the same manner as in Example 4 except that the crosslinked surface layer of Example 7 was not provided and the thickness of the charge transport layer was 25 μm.

  The electrophotographic photosensitive members of Examples 1 to 19 and Comparative Examples 1 to 10 produced as described above were subjected to a paper passing test (normal temperature and normal humidity) of 50,000 sheets of A4 size. First, the photosensitive member was mounted on a process cartridge for an electrophotographic apparatus, and the initial dark portion potential was set to −750 V with a Ricoh imagio Neo271 modified machine using a 655 nm semiconductor laser as an image exposure light source. Thereafter, a paper passing test was started, and the initial portion and the dark portion and exposed portion potential after copying 50,000 sheets, the wear amount of the electrophotographic photosensitive member (the initial photosensitive member film thickness was subtracted from the photosensitive member film thickness after completion of the passing test). Values and film thickness measurements were made using Fischerscope MMS Fischer). The results are shown in Table 1 below.

  As described above, the photoconductor without the cross-linked surface layer protective layer (Comparative Examples 9 and 10) has a large amount of wear, and image deterioration is observed in a paper passing test of 50,000 sheets. The amount of wear is remarkably small, the wear resistance is excellent, and a good image can be obtained continuously. Further, in Comparative Examples 1 to 4, as a result of using bisphenol A type diacrylate as a monomer, the abrasion resistance is higher than that without the crosslinked surface layer protective layer. More than half of the surface layer has been lost. In Comparative Examples 5 to 7 using a tri- or higher functional monomer, although high abrasion resistance was obtained in terms of the number of functional groups, the chargeability was significantly reduced and image deterioration such as image density reduction and thin line thickening occurred. The photoreceptor using the bifunctional monomer of Comparative Example 8 had a large amount of wear, and the crosslinked protective layer was almost lost. Therefore, it can be seen that the photoconductors of the examples of the present application are generally superior to the photoconductor of the comparative example.

Next, with respect to the electrophotographic photosensitive members of Examples 1 to 19 and Comparative Examples 1 to 7 after passing 50,000 sheets, the image density was lowered in a low temperature and low humidity (10 ° C., 15 RH%) environment, and the high temperature and high humidity were low. The output image of the test chart for image evaluation was visually evaluated against the image flow in an environment (30 ° C., 90 RH%). Further, these photoconductors were then exposed for 48 hours under a NOx concentration (NO: 10 ppm, NO ₂ : 40 ppm) condition using a Directec (DY-0102N) NOx exposure tester, and then at room temperature and normal humidity (20 ° C.). , 55 RH%), and the degradation in resolution was visually evaluated using the output image of the test chart for image evaluation.

The image evaluation is described in the following grades for each evaluation item.
・ There is no problem at all. ◎
・ Partially occurs slightly. ○
・ Partly clearly occurs. △
・ It occurs on the entire surface. ×
The results are shown in Table 2 below.

As described above, the examples of the present application cause a decrease in density due to a slight lack of sensitivity in a low-temperature and low-humidity environment in photoconductors (Examples 1, 3, 5, 7 to 9) that do not contain a charge transporting compound in the crosslinked surface layer. There are easy points. In addition, there are some photoreceptors that are used in combination with monomers having three or more functionalities, in which a slight decrease in resolution occurs in the NOx exposure test (Examples 10, 13, 14, 17, and 19). It is very mild and it can be seen that the others (Examples 2, 4, 6, 11, 12, 15, 16, 18) have very good image stability.
On the other hand, in the comparative example having the conventional cross-linked protective layer, the image density under low temperature and low humidity, image flow under high temperature and high humidity, NOx exposure, especially in the photoreceptors (comparative examples 6 to 7) using trifunctional or higher functional monomers. There is a significant decrease in resolution in the test. In addition, photoreceptors using bisphenol A type diacrylate as a monomer (Comparative Examples 1 to 5) are not sufficient although improvement in the image deterioration is seen as compared with the photoreceptor using the above trifunctional or higher monomer. It can be seen that the photoreceptors of Examples 1 to 19 of the present invention clearly have excellent characteristics.
From the above, the electrophotographic photosensitive member having the crosslinked surface layer containing the radical curable composition containing the structure of the general formula (A) shown in Examples 1 to 19 has excellent wear resistance equal to or higher than the conventional one. It can be seen that it has excellent image output stability even under various temperature and humidity environments and exposure to oxidizing gas.

A is an example of a cross-sectional view of the electrophotographic photosensitive member of the present invention. B is another example of a cross-sectional view of the electrophotographic photosensitive member of the present invention. It is another example of sectional drawing of the electrophotographic photosensitive member of this invention. 1 is a schematic diagram illustrating an example of an image forming apparatus of the present invention. FIG. 2 is a schematic diagram illustrating an example of a process cartridge for an image forming apparatus according to the present invention. It is an infrared absorption spectrum (KBr method) of exemplary compound B-1-1 obtained by the synthesis example 1 of the radically polymerizable compound represented by general formula (B) used by this invention. It is an infrared absorption spectrum (NaCl board application | coating) of exemplary compound B-2-4 obtained by the synthesis example 2 of the radically polymerizable compound represented by general formula (B) used by this invention. It is an infrared absorption spectrum of the intermediate body A obtained by the synthesis example 1 of the radically polymerizable compound represented by general formula (C) used by this invention. It is an infrared absorption spectrum of exemplary compound C-1-1 obtained by the synthesis example 1 of the radically polymerizable compound represented by general formula (C) used by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Static elimination lamp 3 Charger charger 4 Eraser 5 Image exposure part 6 Developing unit 7 Charger before transfer 8 Registration roller 9 Transfer paper 10 Transfer charger 11 Separation charger 12 Separation claw 13 Charger before cleaning 14 Fur brush 15 Cleaning blade 101 Photosensitive drum 102 Charging device 103 Exposure 104 Developing device 105 Transfer body 106 Transfer device 107 Cleaning blade

Claims (11)

In an electrophotographic photoreceptor having at least a photosensitive layer that is not radically cured on a conductive support and a crosslinked surface layer containing a radically cured composition, at least the following general formula is contained in the radically cured composition of the crosslinked surface layer: An electrophotographic photoreceptor comprising the structural unit represented by (A).
(In the formula, H represents a 1,1-cyclopentane-diyl group, a 1,1-cyclohexane-diyl group, a 9,9-fluorene-diyl group, and R ₅ and R ₆ are each a straight chain having 1 to 6 carbon atoms. A chain, branched or cyclic alkyl group, a halogen atom or an aryl group is represented, R ₇ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and i and j each represents an integer of 0 to 4) The radical curable composition is a composition formed by applying at least a radically cured coating solution containing a radical polymerizable compound represented by the following general formula (B) to the surface of the photosensitive layer, followed by radical curing. The electrophotographic photosensitive member according to claim 1.
(In the formula, H represents a 1,1-cyclopentane-diyl group, a 1,1-cyclohexane-diyl group, or a 9,9-fluorene-diyl group, and R ₁ and R ₂ are each a straight chain having 1 to 6 carbon atoms. A chain or branched alkylene group, a 1-ketohexylene group, R ₃ and R ₄ each represent a hydrogen atom or a methyl group, and R ₅ and R ₆ each represent a linear, branched or cyclic group having 1 to 6 carbon atoms. Represents an alkyl group, a halogen atom or an aryl group; R ₇ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; n and m each represents an integer of 0 to 4; i and j each represents 0 to 4 Represents an integer.) The radical curing composition is a composition formed by applying radical curing after coating a coating solution containing at least a radical polymerizable compound represented by the following general formula (C) on the surface of the photosensitive layer. The electrophotographic photosensitive member according to claim 1.
(In the formula, H represents 1,1-cyclopentane-diyl group, 1,1-cyclohexane-diyl group, 9,9-fluorene-diyl group, and R ₁₁ , R ₁₂ , R _13, and R ₁₄ are each hydrogen. Represents an atom or a methyl group, R ₅ and R ₆ each represent a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, a halogen atom or an aryl group, and R ₇ represents a hydrogen atom or 1 to 4 carbon atoms. And i and j each represents an integer of 0 to 4.) The radical curable composition is a composition formed by applying at least a coating solution containing a radical polymerizable compound represented by the following general formula (D) to the surface of the photosensitive layer, followed by radical curing. The electrophotographic photosensitive member according to claim 1.
(In the formula, H represents a 1,1-cyclopentane-diyl group, a 1,1-cyclohexane-diyl group, or a 9,9-fluorene-diyl group, and R ₁₅ and R ₁₆ each represents a hydrogen atom or a methyl group. , R ₅ and R ₆ each represent a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, a halogen atom or an aryl group; R ₇ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; n represents an integer of 1 to 50, and i and j each represents an integer of 0 to 4.)   The radical curable composition contains at least one of the radical polymerizable compounds represented by the general formulas (B), (C), and (D), and further contains a monomer having three or more radical polymerizable functional groups. The electrophotographic photosensitive member according to claim 2, wherein the electrophotographic photosensitive member is a composition formed by applying a working solution to the surface of the photosensitive layer and then radical curing.   The radical curable composition comprises at least one of the radical polymerizable compounds represented by the general formulas (B), (C), and (D), and a charge transporting compound further having one or more radical polymerizable functional groups. 6. The electrophotographic photosensitive member according to claim 2, wherein the electrophotographic photosensitive member is a composition formed by applying a coating solution to the surface of the photosensitive layer, followed by radical curing.   The electrophotographic photosensitive member according to claim 1, wherein the radical curable composition is cured by means using light energy.   8. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer that is not radically cured has a structure in which at least a charge generation layer and a charge transport layer are sequentially laminated on a conductive support. body.   An image forming method using an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of claims 1 to 8.   The image forming apparatus comprising at least a charging unit, an exposing unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of claims 1 to 8. An image forming apparatus, comprising:   An electrophotographic photosensitive member according to any one of claims 1 to 8, and at least one means selected from a charging means, an exposure means, a developing means, a transfer means, a cleaning means, and a charge eliminating means are integrated to form an image. A process cartridge for an image forming apparatus, wherein the process cartridge is detachable from the apparatus.