JP5146728B2 - Electrophotographic photosensitive member, image forming method using the same, image forming apparatus, and process cartridge for image forming apparatus - Google Patents

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) at least on the conductive support, an electrophotographic photosensitive member having a photosensitive layer which is not radical curing, the crosslinked surface layer containing a radical curing composition formed by curing by radical polymerization, the electrophotographic photoreceptor radical-curable composition of the cross-linked surface layer is characterized by containing by radical polymerization of a structural unit represented by at least the following general formula (a).
(Wherein R _{1 to} R ₄ each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom, and X is
The divalent group represented by these is represented. )

(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
(Wherein R _{1 to} R ₄ each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom, and X is
R ₅ and R ₆ each represent a linear or branched alkylene group having 1 to 6 carbon atoms and 1-ketohexylene group, and R ₇ and R ₈ represent a hydrogen atom or Represents a methyl group, and n and m each represents an integer of 0 to 4. )

(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
(Wherein R _{1 to} R ₄ each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom, and X is
And R _{7 to} R _{10 each} represents a hydrogen atom or a methyl group. )

(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
(Wherein R _{1 to} R ₄ each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom, and X is
R ₇ and R ₈ represent a hydrogen atom or a methyl group, and n represents an integer of 1 to 50. )

(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.

(Wherein R _{1 to} R ₄ each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom, and X is
The divalent group represented by these is represented. )

<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 radically 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, and further a hexafunctional monomer. This is because the molecular weight is increased by polymerization of at least one of the functional groups. This is because the probability of increasing increases. Therefore, when a monomer having two or less functions is used as a main component, the mechanical strength is lowered, and as described in the previous patent document, it is expected that the abrasion resistance of the crosslinked surface layer is lowered. 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, since X is not a single bond in the structure of the general formula (A), unlike the bisphenol A structure, the bisphenol structure part further extends in a rod shape, and the internal mobility is a structure that is suppressed by steric hindrance. Thus, it is considered that the above-mentioned effect is remarkably exhibited when a thick and hard rod-like structure is contained in the entanglement between molecules. Photoreceptor wear occurs when molecules cut by heat from the cleaning action or discharge of the charger are pulled out by the developer or the cleaning blade, so the entanglement and stacking forces prevent the molecules from being pulled out and wear out. 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 those using the above polyfunctional aliphatic monomer or bisphenol A type bifunctional monomer. It is considered that the environmental stability of the crosslinked surface layer is improved by reducing the concentration. In addition, widening of the actual mesh spacing keeps the molecule moderately mobile, and in addition, the decrease in polar group does not increase the dielectric constant, thus maintaining high charge transportability and reducing 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.
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 mass, preferably 10 to 50% by mass, 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 mass, it is not possible to suppress the intended environmental change, electrical characteristics against oxidizing gas, and image deterioration. On the other hand, when it exceeds 80% by mass, 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, a —COO— group. , —CON (R ₁₁ ) — group (wherein R ₁₁ 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 ₁₂ group (R ₁₂ 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 a phenyl group and a naphthyl group which may have a substituent, or -CONR ₁₃ R ₁₄ (R ₁₃ and R ₁₄ represents a hydrogen atom, an alkyl group such as an optionally substituted methyl group or an ethyl group, an optionally substituted benzyl group, a naphthylmethyl group, or an aralkyl group such as a 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.

(Wherein R _{1 to} R ₄ each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom, and X is
R ₅ and R ₆ each represent a linear or branched alkylene group having 1 to 6 carbon atoms and 1-ketohexylene group, and R ₇ and R ₈ represent a hydrogen atom or Represents a methyl group, and n and m each represents an integer of 0 to 4. )

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 radically 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.
(Wherein R _{1 to} R ₄ each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom, and X is
And R _{7 to} R _{10 each} represents a hydrogen atom or a methyl group. )

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 synthesize | combine easily even if C1-1 process is changed into the following method (C2-1 & C2-2).
Process C2-1

Process C2-2

Moreover, when R < ₇ > -R < ₁₀ > of general formula (C) is all the same group, it is compoundable by the following C3 process.
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.
(Wherein R _{1 to} R ₄ each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom, and X is
R ₇ and R ₈ represent a hydrogen atom or a methyl group, and n represents an integer of 1 to 50. )

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

D1-2 process
Further, when n = 1, it can be synthesized also in the C1-1 step.

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 mass, preferably 20 to 70% by mass, based on the total amount of the constituent materials having curability. is there. If these radically polymerizable compounds are less than 10% by mass, the structural unit of the general formula (A) in the cured composition becomes dilute, and it is not possible to suppress target environmental fluctuations, electrical characteristics with respect to oxidizing gas, and image deterioration. On the other hand, if it exceeds 70% by mass, the mechanical strength such as wear resistance and scratch resistance may be lowered due to the small number of curable functional groups.

<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 trifunctional 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, no problem even by mixing 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 mass, preferably 0 to 50% by mass, 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. The number of radically polymerizable functional groups in one molecule may be one or more, but it is easy to obtain a smooth surface property by suppressing the internal stress of the crosslinked surface layer, and in order to maintain good electrical characteristics. It is preferable that the number of radical polymerizable functional groups is one. When the charge transporting compound has two or more radically polymerizable functional groups, the margin may decrease due to large distortion due to the bulky hole transporting compound being fixed in the cross-linking by a plurality of bonds. Depending on the charge transporting structure and the number of functional groups, irregularities, 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.

[Wherein 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 from each other. Ar ₁ and Ar ₂ represent a substituted or unsubstituted arylene group and 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 ₁₁ 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, acephenanthrylenyl 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 ₁₁ 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 (same as the alkyl group defined in (2) above), an aryl group (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 ₁₁ .
Examples of the substituted or unsubstituted alkylene ether divalent group include the above-mentioned X ₁₁ alkylene ether divalent group.
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 mass, preferably 30 to 70% by mass, based on the total amount of the cross-linked surface layer. If this component is less than 20% by mass, 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 appear with repeated use. Moreover, when it exceeds 80 mass%, content of the hardening composition which has a structural unit shown by general formula (A) will fall, and high abrasion resistance will not be exhibited. Although the electrical characteristics and wear resistance required by the process used are different, it cannot be said unconditionally, but the range of 30 to 70% by mass is most preferable considering the balance of both characteristics.

<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 mass or less, preferably 20% by mass 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.

  Examples of the thermal polymerization initiator include 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 azobisisobutylnitrile, 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. Content of a polymerization initiator is 0.5-40 mass parts with respect to 100 mass parts of total inclusions which have radical polymerizability, Preferably it is 1-20 mass parts.

<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% by mass or less, preferably 10% by mass 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 is based on the total solid content of the coating liquid. 3% by mass 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 mass or less, preferably 30% by mass 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 addition amount is suppressed to 20% by mass or less, preferably 10% by mass 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. Ethers such as dichloromethane, halogens such as dichloromethane, dichloroethane, trichloroethane, and chlorobenzene, aromatics such as benzene, toluene, and xylene, and 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 coating can be performed using a dip coating method, spray coating, bead coating, ring coating method 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.

  As the composition of the crosslinked surface layer coating solution, in addition to the radical polymerizable compound having the structural unit represented by the general formula (A) described above, a binder resin having no radical polymerizable functional group, an antioxidant, a plasticizer. When an additive such as an agent is contained in a large amount, the crosslinking density is lowered, the cured product generated by the reaction and the additive are phase-separated and become soluble in an organic solvent. Specifically, it is important to suppress the total content to 20% by mass or less with respect to the total solid content of the coating liquid.

  Regarding the diluted solvent for the cross-linked surface layer coating solution, if a solvent with a low evaporation rate is used, the remaining solvent may interfere with curing or increase the amount of the lower layer component mixed, causing uneven curing or curing. Reduces density. For this reason, it tends to be soluble in organic solvents. Specifically, tetrahydrofuran, a mixed solvent of tetrahydrofuran and methanol, ethyl acetate, methyl ethyl ketone, ethyl cellosolve and the like are useful, but are selected according to the coating method. Moreover, regarding the solid content concentration, if it is too low for the same reason, it tends to be soluble in an organic solvent. Conversely, the upper limit concentration is constrained by the limitations of film thickness and coating solution viscosity. Specifically, it is desirable to use in the range of 10-50 mass%. As a method for coating the crosslinked surface layer, for the same reason, a method of reducing the solvent content at the time of forming the coating film and the contact time with the solvent is preferable. Specifically, the spray coating method and the amount of the coating liquid are regulated. The ring coating method is preferred. In order to suppress the amount of the lower layer component to be mixed, it is also effective to use a polymer charge transport material as the charge transport layer and to provide an insoluble intermediate layer with respect to the coating solvent for the crosslinked surface layer.

As curing conditions for the cross-linked surface layer, if the energy of heating or light irradiation is low, the curing is not completely completed and the solubility in the organic solvent is increased. On the other hand, when cured with very high energy, the curing reaction becomes non-uniform, and it tends to increase the number of uncrosslinked parts and radical stopping parts and to form an aggregate of minute cured products. For this reason, it may become soluble in an organic solvent. To insolubilize in an organic solvent, the heat curing conditions are preferably 100 to 170 ° C. and 10 minutes to 3 hours, and the curing conditions by UV light irradiation are 50 to 1000 mW / cm ² and 5 seconds to 5 minutes. In addition, it is desirable to control the temperature rise to 50 ° C. or less to suppress non-uniform curing reaction.

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. That is, the photosensitive layer that is not radically cured 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-vinylcarbazole, 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, 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 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 carbazole skeleton, azo pigments having triphenylamine skeleton, azo pigments having diphenylamine skeleton, dibenzothiophene skeleton Azo pigments having a fluorenone skeleton, azo pigments having an oxadiazole skeleton, azo pigments having a bis-stilbene skeleton, azo pigments having a distyryl oxadiazole skeleton, azo pigments having a 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. No. 1, JP-A 09-104746, JP 09-110974, JP 09-110976, JP 09-157378, JP 09-221544, JP 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 coating can be performed using a dip coating method, spray coating, bead coating, ring coating method 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.

As the binder resin, 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 mass, preferably 40 to 150 parts by mass with respect to 100 parts by mass 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 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 a plasticizer that can be used in combination with the charge transport layer, those used as a plasticizer for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is 0 with respect to 100 parts by mass of the binder resin. About 30 parts by mass 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 mass is appropriate for 100 parts by mass.
The thickness of the charge transport layer is suitably about 5 to 40 μm, preferably about 10 to 30 μm.

  As described above in the method for preparing a crosslinked surface layer, the crosslinked surface layer is coated with the crosslinked surface layer coating solution of the present invention on such a charge transport layer, dried as necessary, and then subjected to light, heat or radiation. The curing reaction is initiated by energy, and a crosslinked surface layer is formed. 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 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. In addition, since there is no charge transport capability, a significant decrease 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.

<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 mass relative to the total amount of the photosensitive layer, the binder resin contained in the photosensitive layer is 20 to 80% by mass, and the charge transport material is 10 to 70% by mass. Part is used well.
The film thickness of the photosensitive layer is suitably about 5 to 30 μm, preferably about 10 to 25 μm.

  When the cross-linked surface layer is a surface portion of a photosensitive layer having a single layer structure, the cross-linked surface layer coating solution of the present invention is applied onto the photosensitive layer as described above, and after drying, if necessary, light, heat or radiation It cures by the energy of and forms 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 crosslinking 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. In addition, since there is no charge transport capability, a significant decrease 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 above-mentioned cross-linked surface layer preparation method, and if necessary, dried, light, heat or The curing reaction is initiated by the energy of the radiation, 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 underlying 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 this invention is 0.01-10 mass% with respect to the total mass of the layer to add.

<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 a 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 system 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. Other cleaning means include a web method, a magnet brush method, and the like, but each may be used alone or in combination.
Next, a neutralizing unit is used for the purpose of removing the latent image on the photoreceptor as required. 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.
The 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. 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
30 g (0.087 mol) of 4,4 '-(2,2'-(1,4-phenylene) bis (propane-2,2-diyl)) diphenol is dissolved in 200 ml of tetrahydrofuran and sodium hydroxide in a nitrogen stream. (NaOH: 88.3 g, water: 56 ml) was added dropwise. This solution was cooled to 6 ° C., and 31.5 g (0.348 mol) of acrylic acid chloride was added dropwise over 1 hour. Thereafter, the reaction was terminated by stirring for 2.5 hours. The reaction solution was poured into water and extracted with toluene. This extract was repeatedly washed with water. The reaction solution was poured into water and extracted with toluene. Thereafter, the solvent was removed from the toluene solution, and purification was performed by column chromatography (adsorption medium: silica gel, developing solvent: toluene / ethyl acetate (1/1)). Methanol was added to the obtained colorless oil to precipitate crystals. Thus, exemplary compound B-1-1 {4,4 ′-(2,2 ′-(1,4-phenylene) bis (propane-2,2-diyl)) bis (4,1-phenylene) diacrylate } Was obtained 24.12 g (yield = 61.0%). The melting point and elemental analysis value of the obtained compound are shown below. An infrared absorption spectrum is shown in FIG.
Melting point: 155.0-156.5 ° C
Elemental analysis value (%)
C (%) H (%) N (%)
Actual value 79.30 6.61 0.00
Calculated value 79.27 6.65 0.00

<Synthesis Example 2 of Radical Polymerizable Compound Represented by General Formula (B) Used in the Present Invention>
(1) Synthesis of B-1-4
4,4 '-(2,2'-(1,3-phenylene) bis (propane-2,2-diyl)) diphenol 30g (0.087mol) is dissolved in 200ml of tetrahydrofuran, and sodium hydroxide in nitrogen stream. (NaOH: 88.3 g, water: 56 ml) was added dropwise. This solution was cooled to 6 ° C., and 31.5 g (0.348 mol) of acrylic acid chloride was added dropwise over 1 hour. Thereafter, the reaction was terminated by stirring for 2.5 hours. The reaction solution was poured into water and extracted with toluene. This extract was repeatedly washed with water. The reaction solution was poured into water and extracted with toluene. Thereafter, the solvent was removed from the toluene solution, and purification was performed by column chromatography (adsorption medium: silica gel, developing solvent: toluene / ethyl acetate (1/1)). Methanol was added to the obtained colorless oil to precipitate crystals. In this way, exemplary compound B-1-4 {4,4 ′-(2,2 ′-(1,3-phenylene) bis (propane-2,2-diyl)) bis (4,1-phenylene) diacrylate } Of 31.83 g of white crystals (yield = 80.5%). The melting point and elemental analysis value of the obtained compound are shown below. An infrared absorption spectrum is shown in FIG.
Melting point: 106.0-107.5 ° C
Elemental analysis value (%)
C (%) H (%) N (%)
Actual value 79.33 6.62 0.00
Calculated value 79.27 6.65 0.00
As described above, other diphenol compounds can be synthesized in the same manner.

<Synthesis Example 1 of Radical Polymerizable Compound Represented by General Formula (C) Used in the Present Invention>
(1) 3,3 '-(4,4'-(2,2 '-(1,3-phenylene) bis (propane-2,2-diyl)) bis (4,1-phenylene)) bis (oxy Synthesis of dipropane-1,2-diol intermediate
10.0 g (28.9 mmol) of 4,4 '-(2,2'-(1,3-phenylene) bis (propane-2,2-diyl)) diphenol and 9.5 g (63.5 mmol) of glycidyl methacrylate The resultant was dissolved in 50 ml of toluene, 0.25 ml of triethylamine was added, and the mixture was stirred at 95 ° C. for 10 hours in an argon stream. Thereafter, 29 ml of a 10% by mass aqueous sodium hydroxide solution and 20 ml of toluene were added at room temperature, followed by stirring at 91 ° C. for 8 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)). Thus, colorless powdery 3,3 '-(4,4'-(2,2 '-(1,3-phenylene) bis (propane-2,2-diyl)) bis (4,1-phenylene) )) 12.05 g (yield = 84.4%) of bis (oxy) dipropane-1,2-diol was obtained. An infrared absorption spectrum of the obtained intermediate compound is shown in FIG.

(2) Synthesis of C-1-3
3,3 '-(4,4'-(2,2 '-(1,3-phenylene) bis (propane-2,2-diyl)) bis (4,1-phenylene)) bis (oxy) dipropane- 5.0 g (10.1 mmol) of 1,2-diol was dissolved in 40 ml of dimethylacetamide. 7.7 g (60.7 mmol) of 3-chloropropionyl chloride was added at 3 ° C. in an argon stream and stirred at room temperature for 5 hours. Thereafter, 17 ml of triethylamine was added at 3 ° C., and the mixture was stirred at 60 for 5 hours to complete the reaction. The reaction solution was poured into water and extracted with dichloromethane. This extract was repeatedly washed with water. Thereafter, the solvent was removed from the dichloromethane solution, and purification was performed by column chromatography (adsorption medium: silica gel, developing solvent: n-hexane / ethyl acetate (2/1)). In this way, 5.55 g (yield = 77.3%) of Exemplified Compound C-1-3 on oil was obtained. The infrared absorption spectrum of the obtained compound C-1-3 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-1-3 4,4 '-(2,2'-(1,3-phenylene) bis (propane-2,2) was added to a reaction vessel equipped with a stirrer, thermometer, and dropping funnel. -diyl)) 6.9 g (20 mmol) of diphenol, 18.51 g (200 mmol) of epichlorohydrin 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, excess epichlorohydrin was recovered under reduced pressure, toluene was added, the organic layer was washed with water, dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and reprecipitated in methanol. Filtration gave 8.05 g of colorless powder. The melting point was amorphous.
This powder was dissolved again in 80 ml of toluene, put into a reaction vessel together with 0.72 g (10 mmol) of acrylic acid and 0.2 ml of triethylamine, and reacted at 80 ° C. for 3 hours. After cooling, it was washed with water, concentrated under reduced pressure, reprecipitated in methanol, and filtered to obtain 7.85 g of a colorless powder. 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 hours. After removing the activated clay, it was reprecipitated in methanol and filtered to obtain 7.6 g of a colorless powder.
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 of 1 to 5.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to a following example. In addition, all "parts" used in an Example represent a mass part.
<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. On this photosensitive layer, a cross-linked surface layer coating solution having the following composition is spray-coated and naturally dried for 20 minutes, and then a metal halide lamp: 160 W / cm, irradiation distance: 120 mm, irradiation intensity: 500 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]
・ 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: 306 parts Cyclohexanone: 76 parts Tetrahydrofuran solution of 1% silicone oil: 0.2 parts (KF50-100CS, manufactured by Shin-Etsu Chemical Co., Ltd.)

[Crosslinked surface layer coating solution]
-Radical polymerizable compound of the above structural formula (Exemplary Compound C-1-3): 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.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of the structural formula (Exemplary Compound B-1-4): 10 parts-Monomer having 3 or more radical polymerizable functional groups: 10 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku Co., Ltd.)
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 and the film thickness was changed to 5 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of the structural formula (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 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

<Example 4>
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 naturally dried for 20 minutes, and then a metal halide lamp: 160 W / cm, irradiation distance: 120 mm, irradiation intensity: 500 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]
-Alkyd resin: 6 parts (Beccosol 1307-60-EL, 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]
-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]
-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]
-Radical polymerizable compound of the structural formula (Exemplary Compound C-1-3): 10 parts-Monomer having 3 or more radical polymerizable functional groups: 10 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku Co., Ltd.)
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 4 except that the crosslinked surface layer coating solution of Example 4 was changed to the following.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of the structural formula (Exemplary Compound B-1-1): 10 parts-Monomer having three or more radical polymerizable functional groups: 10 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku)
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 4 except that the crosslinked surface layer coating solution of Example 4 was changed to the following and the film thickness was changed to 7 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of the structural formula (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 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

<Example 7>
An electrophotographic photosensitive member was produced in the same manner as in Example 4 except that the crosslinked surface layer coating solution of Example 4 was changed to the following and the film thickness was changed to 6 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of the above structural formula (Exemplary Compound B-1-4): 5 parts-Monomer having 3 or more radical polymerizable functional groups: 5 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku 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

<Example 8>
An electrophotographic photosensitive member was prepared in the same manner as in Example 4 except that the crosslinked surface layer coating solution of Example 4 was changed to the following and the film thickness was changed to 5 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of the above structural formula (Exemplary Compound B-1-13): 5 parts Diacrylate synthesized from diphenol YP-90 manufactured by Mitsui Petrochemical Co., Ltd. in the same manner as Synthesis Example 1-Radical polymerizable Monomers with 3 or more 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

<Example 9>
An electrophotographic photosensitive member was prepared in the same manner as in Example 4 except that the crosslinked surface layer coating solution of Example 4 was changed to the following and the film thickness was changed to 10 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of the structural formula (Exemplary Compound C-1-3): 5 parts-Monomer having 3 or more radical polymerizable functional groups: 1 part 3 Trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku Co., Ltd.) )
・ Monomer 2 with 3 or more radical polymerizable functional groups: 2 parts Caprolactone-modified dipentaerythritol hexaacrylate (KAYARAD DPCA-120, 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 10>
An electrophotographic photosensitive member was produced in the same manner as in Example 4 except that the crosslinked surface layer coating solution of Example 4 was changed to the following and the film thickness was changed to 7 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of the structural formula (Exemplary Compound D-1-3): 4 parts-Monomer having 3 or more radical polymerizable functional groups: 6 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku 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

<Example 11>
An electrophotographic photosensitive member was produced in the same manner as in Example 4 except that the crosslinked surface layer coating solution of Example 4 was changed to the following and the film thickness was changed to 8 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of the above structural formula (Exemplary Compound C-1-3): 5 parts-Monomer having 3 or more radical polymerizable functional groups: 1 part 2 Trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku Co., Ltd.) )
・ Monomer 2 with 3 or more radical polymerizable functional groups: 3 parts Caprolactone-modified dipentaerythritol hexaacrylate (KAYARAD DPCA-120, Nippon Kayaku)
-Charge transporting compound having one or more radical polymerizable functional groups: 10 parts (Exemplary Compound NO. 182)
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 prepared in the same manner as in Example 4 except that the crosslinked surface layer coating solution of Example 4 was changed to the following and the film thickness was changed to 5 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of the structural formula (Exemplary Compound C-1-3): 10 parts-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 prepared in the same manner as in Example 4 except that the crosslinked surface layer coating solution of Example 4 was changed to the following and the film thickness was changed to 5 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable compound of the structural formula (Exemplary Compound C-1-3): 10 parts-Charge transporting compound having one or more radical polymerizable functional groups: 10 parts (Exemplary Compound NO. 146)
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 of Example 1 was not provided and the film thickness of the photosensitive layer was 25 μm.
<Comparative example 2>
An electrophotographic photosensitive member was produced in the same manner as in Example 4 except that the crosslinked surface layer of Example 4 was not provided and the thickness of the charge transport layer was changed to 21 μm.

<Comparative 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 monomer having the following structural formula: 20 parts
Ethoxylated bisphenol A 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 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: 10 parts
Ethoxylated bisphenol A diacrylate (ABE-300, Shin-Nakamura Chemical Co., Ltd.)
-Monomer having 3 or more radical polymerizable functional groups: 10 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, Nippon Kayaku)
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 1 except that the crosslinked surface layer coating solution of Example 1 was changed to the following and the film thickness was changed to 5 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable monomer of the following structural formula: 5 parts
Ethoxylated bisphenol A 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 4 except that the crosslinked surface layer coating solution of Example 4 was changed to the following.
[Crosslinked surface layer coating solution]
-Radical polymerizable monomer having the following structural formula: 10 parts
Ethoxylated bisphenol A diacrylate (ABE-300, Shin-Nakamura Chemical Co., Ltd.)
-Monomer having 3 or more radical polymerizable functional groups: 10 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, 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 4 except that the crosslinked surface layer coating solution of Example 4 was changed to the following.
[Crosslinked surface layer coating solution]
-Monomer having 3 or more radical polymerizable functional groups 1: 10 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, Nippon Kayaku)
・ Monomer 2 having 3 or more radical polymerizable functional groups: 10 parts caprolactone-modified dipentaerythritol hexaacrylate (KAYARAD DPCA-120, manufactured by Nippon Kayaku Co., Ltd.)
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 prepared in the same manner as in Example 4 except that the crosslinked surface layer coating solution of Example 4 was changed to the following and the film thickness was changed to 10 μm.
[Crosslinked surface layer coating solution]
-Monomer having 3 or more radical polymerizable functional groups: 10 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 9>
An electrophotographic photosensitive member was produced in the same manner as in Example 4 except that the crosslinked surface layer coating solution of Example 4 was changed to the following and the film thickness was changed to 7 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable monomer of the following structural formula: 5 parts
(KAYARAD NPGDA, manufactured by Nippon Kayaku)
・ 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 10>
An electrophotographic photosensitive member was prepared in the same manner as in Example 4 except that the crosslinked surface layer coating solution of Example 4 was changed to the following and the film thickness was changed to 10 μm.
[Crosslinked surface layer coating solution]
-Radical polymerizable monomer of the following structural formula: 5 parts
Ethoxylated bisphenol A diacrylate (ABE-300, Shin-Nakamura Chemical Co., Ltd.)
-Monomer having 3 or more radical polymerizable functional groups 1: 3 parts Trimethylolpropane triacrylate (KAYARAD TMPTA, Nippon Kayaku)
・ Monomer 2 with 3 or more radical polymerizable functional groups: 2 parts Caprolactone-modified dipentaerythritol hexaacrylate (KAYARAD DPCA-120, 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 11>
An electrophotographic photosensitive member was prepared in the same manner as in Example 4 except that the crosslinked surface layer coating solution of Example 4 was changed to the following and the film thickness was changed to 5 μm.
[Crosslinked surface layer coating solution]
・ The following commercially available radical polymerizable monomer: 5 parts Bisphenol F EO-modified diacrylate (M-208, manufactured by Toa Gosei)
・ 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

  The electrophotographic photosensitive members of Examples 1 to 13 and Comparative Examples 1 to 11 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 photoconductor is mounted on a process cartridge for an electrophotographic apparatus, and the amount of wear of the electrophotographic photoconductor after copying 50,000 sheets with a modified Ricoh's image Neo Neo270 using a 655 nm semiconductor laser as an image exposure light source (copying) The value obtained by subtracting the initial photoreceptor thickness from the later photoreceptor thickness was measured. The results are shown in Table 1 below.

  As described above, the amount of wear of the photoconductor of this embodiment is much smaller than that of the photoconductor having no cross-linked surface layer (Comparative Examples 1 and 2), and is excellent in wear resistance. In Comparative Example 3, as a result of using bisphenol A-type diacrylate as a monomer, although the abrasion resistance was superior to that without the crosslinked surface layer, the crosslinked surface layer was completely eliminated after printing only 50,000 sheets. . On the other hand, the photoreceptors of the examples of the present application all have excellent wear resistance. In addition, Comparative Examples 4 to 11 are examples in which the wear resistance is improved by the crosslinked surface layer, and the amount of wear is small, but in comparison with these, the examples of the present application show equivalent or slightly superior wear resistance. .

Next, the electrophotographic photoreceptors of Examples 1 to 13 and Comparative Examples 4 to 11 in which the crosslinked surface layer remained were imaged at low temperature and low humidity (10 ° C., 15 RH%) and at high temperature and high humidity (30 ° C., 90 RH%). An image of an evaluation test chart was output, and the presence or absence of occurrence was visually evaluated for image density fluctuation, image flow, and resolution reduction. Further, the photoconductor subjected to image evaluation under high temperature and high humidity was exposed for 48 hours under the conditions of NOx concentration (NO: 10 ppm, NO ₂ : 30 ppm) with a direct recording (DY-0102N) NOx exposure tester. Thereafter, image output was carried out under normal temperature and normal humidity (20 ° C., 55 RH%), and the presence or absence of occurrence was visually evaluated for image density fluctuation, image flow, and resolution reduction as before.

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, in the examples of the present application, when the cross-linked surface layer does not contain a charge transporting compound, there is a point that it is likely to cause a decrease in density due to a slightly low sensitivity in a low-temperature and low-humidity environment. It can be seen that it has stability.
On the other hand, in the comparative example having the conventional crosslinked protective layer, the image evaluation under the low temperature and low humidity shows the same quality as the embodiment of the present invention, but the image flow tends to occur under the high temperature and high humidity. The resolution is likely to decrease.

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 13 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.
Therefore, by using an electrophotographic photoreceptor having a photosensitive layer that is not radically cured of the present invention and a crosslinked surface layer containing a radically cured composition containing the structure of the general formula (A), the abrasion resistance is high, A photoconductor having good electrical characteristics and excellent environmental stability and gas resistance was realized. Therefore, by using this photoreceptor, it is possible to provide a high-performance and highly reliable image forming process, 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.

FIG. 3 is a diagram illustrating a layer configuration of an electrophotographic photosensitive member of the present invention. It is a figure showing another layer structure 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. It is the schematic which shows an example of the process cartridge of this invention. It is an infrared absorption spectrum of B-1-1 obtained by the compatibility example of the radically polymerizable compound. It is an infrared absorption spectrum of B-1-4 obtained by the compatibility example of the radically polymerizable compound. 3,3 '-(4,4'-(2,2 '-(1,3-phenylene) bis (propane-2,2-diyl)) bis (4 , 1-phenylene)) bis (oxy) dipropane-1,2-diol intermediate absorption spectrum. It is an infrared absorption spectrum of C-1-3 obtained by the compatibility example of a radically polymerizable compound.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Static elimination lamp 3 Charger charger 5 Image exposure part 6 Developing unit 7 Charger before transfer 9 Transfer body 10 Transfer charger 11 Separation charger 12 Separation nail 13 Charger before cleaning 14 Fur brush 15 Cleaning blade 101 Photoconductor 102 Charging means 103 Exposure Means 104 Developing means 105 Transfer body 106 Transfer means 107 Cleaning means

Claims (11)

At least on the conductive support, a photosensitive layer which is not radical curing, an electrophotographic photoreceptor having a crosslinked surface layer containing a radical curing composition formed by curing by radical polymerization, crosslinked surface layer electrophotographic photoreceptor radical-curable composition is characterized in that it contains by radical polymerization of a structural unit represented by at least the following general formula (a).
(Wherein R _{1 to} R ₄ each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom, and X is
The divalent group represented by these is represented. ) 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.
(Wherein R _{1 to} R ₄ each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom, and X is
R ₅ and R ₆ each represent a linear or branched alkylene group having 1 to 6 carbon atoms and 1-ketohexylene group, and R ₇ and R ₈ represent a hydrogen atom or Represents a methyl group, and n and m each represents an integer of 0 to 4. ) 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.
(Wherein R _{1 to} R ₄ each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom, and X is
And R _{7 to} R _{10 each} represents a hydrogen atom or a methyl group. ) 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.
(Wherein R _{1 to} R ₄ each represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a halogen atom, and X is
R ₇ and R ₈ represent a hydrogen atom or a methyl group, and n represents an integer of 1 to 50. )   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 performing 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, which is detachable from the apparatus.