JP2012002997A - Production method for electrophotographic photoreceptor, electrophotographic photoreceptor, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method for an electrophotographic photoreceptor having a photosensitive layer and a surface layer on a conductive support, the photoreceptor comprising an excellent state of film surface of the surface layer that is sufficiently and uniformly cured throughout the surface layer, high and stable abrasion resistance and scratch resistance, and excellent electrical property, realizing long-term high-quality images.SOLUTION: A surface layer is formed by including a step of forming a coating film as a surface layer using a coating liquid containing a radical polymerizable compound, and thereafter a step of curing the coating film by irradiating light energy from a light source of an LED. In the curing step of the coating film, the electrophotographic photoreceptor after forming the coating film that is the surface layer is moved into an airtight container that is provided with an LED irradiation unit and is sealed. In the step of irradiating with light energy, an inert gas is injected while discharging a gas from the airtight container.

Description

  The present invention relates to an electrophotographic photosensitive member having high wear resistance and scratch resistance, good electrical characteristics, and capable of maintaining high image quality over a long period of time, and more specifically, a coating film formed by a coating solution The present invention relates to an electrophotographic photosensitive member having a surface layer cured by irradiating light energy (LED light) under thermal control, a method for producing the same, and an image forming apparatus including the electrophotographic photosensitive member.

  In recent years, organic photoconductors (OPCs) 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. The reasons for this include, for example, (1) optical characteristics such as the width of the light absorption wavelength range and the amount of absorption, (2) electrical characteristics such as high sensitivity and stable charging characteristics, and (3) selection of materials. Examples include a wide range, (4) ease of production, (5) low cost, and (6) non-toxicity.

On the other hand, the diameter of the photoreceptor has recently been reduced along with the downsizing of the image forming apparatus, and higher durability of the photoreceptor has been eagerly desired due to the increase in the speed of the machine and the maintenance-free movement.
From this point of view, the organic photoreceptor is generally soft because the surface layer is mainly composed of a low molecular charge transport material and an inert polymer material, and when used repeatedly in an electrophotographic process, the development system And the mechanical load of the cleaning system has a drawback that wear tends to occur. In addition, as the particle size of the toner particles is reduced due to the demand for higher image quality, the rubber hardness of the cleaning blade is increased (increased) and the contact pressure is increased (increased) for the purpose of improving cleaning properties. This also increases the amount of wear on the photoreceptor. Such abrasion of the photoconductor deteriorates electrical characteristics (deterioration of sensitivity, decrease in chargeability, etc.), and causes abnormal images such as image density reduction and background stains. In addition, scratches in which wear locally occurs result in streak-like stain images due to poor cleaning. Under the present circumstances, the wear and scratches are rate-determined and the life of the photoconductor has been replaced. Therefore, it is indispensable to reduce the above-mentioned wear amount in order to increase the durability of the organic photoreceptor, and this is the most pressing issue in this field.

  Techniques for improving the abrasion resistance of the photoreceptor include (1) using a curable binder for the surface layer (see, for example, Patent Document 1), and (2) using a polymeric charge transport material ( For example, refer patent document 2), (3) what dispersed the inorganic filler in the surface layer (for example, refer patent document 3), etc. are mentioned. Among these techniques, the one using the curable binder (1) has poor compatibility with the charge transport material, and the residual potential increases due to impurities such as polymerization initiators and unreacted residues. There is a tendency that a decrease in density tends to occur. In addition, the polymer charge transport material (2) and the inorganic filler (3) dispersed can be improved to some extent, but are required for organic photoreceptors. The durability has not been fully satisfied. Further, in the case where the inorganic filler (3) is dispersed, the residual potential increases due to traps present on the surface of the inorganic filler, and the image density tends to decrease. These technologies (1), (2), and (3) are sufficient to satisfy the overall durability including the electrical durability and mechanical durability required for the organic photoreceptor. Has not reached.

  Furthermore, a photoreceptor containing a polyfunctional acrylate monomer cured product in order to improve the abrasion resistance and scratch resistance of (1) is also known (for example, see Patent Document 4). However, in this photoreceptor, although there is a description that the polyfunctional acrylate monomer cured product is contained in the protective layer provided on the photosensitive layer, the protective layer may contain a charge transport material. However, when the surface layer contains a low-molecular charge transporting substance, there is a problem of compatibility with the cured product. In some cases, the molecular charge transport material is precipitated and the cloudiness phenomenon occurs, and the mechanical strength is also lowered. Furthermore, since this photoconductor specifically reacts with a monomer in a state containing a polymer binder, curing does not proceed sufficiently, and there is a problem of compatibility between the cured product and the binder resin. There was a tendency for surface irregularities due to phase separation to cause poor cleaning.

  As an alternative to wear resistance technology for photosensitive layers, a charge transport layer formed using a coating solution comprising a monomer having a carbon-carbon double bond, a charge transport material having a carbon-carbon double bond, and a binder resin is used. The binder resin has a carbon-carbon double bond and is reactive to the charge transport material, and the double resin is known to be provided. Those having no bond and no reactivity are included. This photoconductor is attracting attention because it has both wear resistance and good electrical characteristics. However, when a non-reactive binder resin is used, the binder resin, the monomer, and the charge transport material are used. There was a poor compatibility with the cured product produced by the reaction, and surface irregularities were generated during the cross-linking from the layer separation, and a tendency to cause poor cleaning was observed.

  Further, as described above, in this case, the binder resin prevents the curing of the monomer, and what is specifically described as the monomer used in the photoreceptor is a bifunctional one. The monomer has a small number of functional groups and a sufficient crosslinking density cannot be obtained, and these points have not yet been satisfactory in terms of wear resistance. Further, even when a reactive binder is used, it is difficult to achieve both the binding amount and the crosslinking density of the charge transport material due to the low number of functional groups contained in the monomer and the binder resin, and the electrical characteristics and The wear resistance was not sufficient.

A photosensitive layer containing a compound obtained by curing a charge transport material having two or more chain polymerizable functional groups in the same molecule is also known (for example, see Patent Document 6).
However, in this photosensitive layer, a bulky charge transport material has two or more chain-polymerizable functional groups, so that distortion occurs in the cured product, resulting in high internal stress, and the protective layer is prone to roughening and cracking over time. In some cases, it does not have sufficient durability.

  In response to the above problems, the protective layer is made of a cross-linked resin layer obtained by curing a radically polymerizable monomer having no charge transporting structure and a radically polymerizable compound having a charge transporting structure by irradiation with light energy. It has been proposed to improve wear resistance (see, for example, Patent Document 7, Patent Document 8, and Patent Document 9).

  However, as a disadvantage of the radical polymerization method by irradiation with light energy, there is curing inhibition due to oxygen inhibition. As a method of suppressing this, a method of curing in an inert gas atmosphere (for example, see Patent Document 10) has been proposed. However, since the method of replacing with an inert gas cannot sufficiently remove oxygen, further improvement is required.

  In recent years, in place of conventional ultraviolet light using an electroded or electrodeless ultraviolet lamp as a light source, a protective layer for a photoconductor by a light emitting diode (LED) light capable of emitting light energy of only a required wavelength. A method of photocuring (surface layer: crosslinked resin layer) has been proposed (see, for example, Patent Document 11). The LED generates very little heat, and the temperature change of the substrate that is the object to be irradiated is very small. Further, since the light emitting device has a very simple cooling mechanism, the light emitting device is very small as compared with the conventional ultraviolet lamp device, and has an advantage that the installation location is not limited. Further, since the LED light source has a small amount of unnecessary light that ozonizes oxygen in the air, the amount of active gas generated is small (paragraph [0021] of Patent Document 11), and the necessity of introducing an inert gas is negative. It is. However, it has been found in the present invention that further improvement is required because curing inhibition due to oxygen inhibition occurs as in the case of conventional ultraviolet lamps.

  The present invention has been made in view of the above prior art, and the surface state of the surface layer of an electrophotographic photosensitive member having at least a photosensitive layer and a surface layer on a conductive support is good, and the surface An electrophotographic photosensitive material that is fully cured inside the layer, has a uniform cured state, has high wear and scratch resistance, is stable, has good electrical characteristics, and can achieve high image quality over a long period of time. An object of the present invention is to provide a method for producing a photoconductor, an electrophotographic photosensitive member produced thereby, and an image forming apparatus provided with the electrophotographic photosensitive member.

As a result of intensive studies, the present inventors have found that the above problems can be solved by the inventions described in the following [1] to [10], and have reached the present invention. Hereinafter, the present invention will be specifically described.
[1]: In a method for producing an electrophotographic photoreceptor having at least a photosensitive layer and a surface layer on a conductive support, a coating film as a surface layer is formed using a coating solution containing a radical polymerizable compound The surface layer is formed by including a step of curing the coating film by irradiating light energy using an LED as a light source after the step of performing the coating step. The electrophotographic photosensitive member after the film forming step is moved into the sealed container in which the LED irradiation unit is installed, and after sealing the sealed container, while irradiating the light energy, while discharging the gas in the sealed container, On the other hand, a method for producing an electrophotographic photosensitive member comprising injecting an inert gas.
[2] The method for producing an electrophotographic photosensitive member according to [1], wherein the inert gas is nitrogen, helium, neon, argon, xenon, or radon alone or in combination.
[3] The method for producing an electrophotographic photosensitive member according to [1] or [2], wherein the specific gravity of the inert gas is smaller than oxygen.
[4]; The radical polymerizable compound is a radical polymerizable monomer (A) having no charge transporting structure and / or a radical polymerizable compound (B) having a charge transporting structure. [1] The method for producing an electrophotographic photosensitive member according to any one of [1] to [3].
[5] The method for producing an electrophotographic photosensitive member according to the above [4], wherein the radical polymerizable monomer (a) having no charge transporting structure is trifunctional or more.
[6] The item [4] or [5], wherein the functional group of the radical polymerizable monomer (a) having no charge transporting structure is an acryloyloxy group and / or a methacryloyloxy group. A process for producing an electrophotographic photoreceptor according to 1.
[7] The electrophotographic photosensitive member according to any one of [4] to [6], wherein the radical polymerizable compound (b) having the charge transporting structure is monofunctional. Production method.
[8] The item [4] to [7], wherein the functional group of the radical polymerizable compound (b) having the charge transporting structure is an acryloyloxy group and / or a methacryloyloxy group. The method for producing an electrophotographic photosensitive member according to any one of the above.
[9] An electrophotographic photosensitive member produced by the method according to any one of [1] to [8].
[10] An image forming apparatus comprising at least the electrophotographic photosensitive member according to the item [9], and having a mechanism for applying a lubricant to the surface of the electrophotographic photosensitive member.

  The production method of the electrophotographic photoreceptor of the present invention (having at least a photosensitive layer and a surface layer on a conductive support) is obtained by applying a coating film as a surface layer using a coating solution containing a radical polymerizable compound. After the formation, the electrophotographic photosensitive member after forming the coating film as the surface layer is moved into a sealed container provided with an LED irradiation unit, and after sealing the sealed container, the sealed container is irradiated with the light energy. Since the inert gas is injected while discharging the gas inside, the curing failure due to oxygen inhibition, which is a problem when curing by conventional ultraviolet irradiation, is remarkably improved, so the wear resistance is improved. . In addition, abnormal images generated when peroxide radicals are combined with active radicals and fixed to the surface layer, particularly image blurring noticeable in an image forming apparatus that applies a lubricant to the surface of an electrophotographic photosensitive member, are improved. The film surface is in good condition and is sufficiently cured throughout the surface layer, the cured state is uniform, wear resistance and scratch resistance are excellent, and a reliable and stable surface layer is obtained.

Therefore, the electrophotographic photosensitive member has high abrasion resistance and scratch resistance, is stable with the occurrence of abnormal images being suppressed and has good electrical characteristics, and has high durability, high performance, in addition to the human body and the environment. It is possible to realize high image quality over a long period of time with little load.
The image forming apparatus provided with the electrophotographic photosensitive member of the present invention uses an electrophotographic photosensitive member having good wear resistance, scratch resistance, electrical characteristics, high durability, and high performance. Even if the linear velocity is high), an abnormal image is not generated and a stable high quality image can be continuously output.

It is a block diagram which shows an example which installed the LED-UV irradiation apparatus and the electrophotographic photosensitive body in the vacuum chamber in this invention. It is a block diagram which shows another example which installed the LED-UV irradiation apparatus and the electrophotographic photoreceptor in this invention in the vacuum chamber. It is a schematic sectional drawing which shows an example of the layer structure of the electrophotographic photoreceptor in this invention. It is a schematic sectional drawing which shows another example of the layer structure of the electrophotographic photoreceptor in this invention. 1 is a schematic cross-sectional view illustrating an example of an image forming apparatus of the present invention. It is a spectrum figure which shows the light emission peak (wavelength 365nm) of the LED light source used for formation of the surface layer in an Example.

  As described above, the method for producing an electrophotographic photoreceptor according to the present invention is a method for producing an electrophotographic photoreceptor having at least a photosensitive layer and a surface layer on a conductive support, and a coating containing a radical polymerizable compound. After the step of forming a coating film as a surface layer using a liquid, the surface layer is formed by including a step of curing the coating film by irradiation with light energy using an LED as a light source. In the film curing step, the electrophotographic photosensitive member after the step of forming the coating film as the surface layer is moved into a sealed container provided with an LED irradiation unit, and after sealing the sealed container, the light energy is irradiated. The method further includes injecting an inert gas while discharging the gas in the sealed container.

That is, when forming the surface layer, the electrophotographic photosensitive member after forming a coating film as a surface layer containing a radical polymerizable compound and a solvent is moved into a sealed container provided with an LED irradiation unit, and the sealed After sealing the container, irradiation with light energy using an LED as a light source in an atmosphere excluding oxygen accelerates the crosslinking reaction of the radical polymerizable compound, and at a uniform rate to the inside of the coating film (surface layer) The reaction proceeds, and the fixation of peroxide radicals to the surface layer is further reduced.
As a result, it is possible to obtain excellent film surface properties, cure sufficiently throughout the surface layer, obtain high wear resistance and scratch resistance, and achieve excellent cleaning characteristics and high image quality over a long period of time. A method for producing a photographic photoreceptor is achieved.

The reason why a good film surface property, uniform and high wear resistance and scratch resistance over the inside of the surface layer can be obtained by the present invention is that the surface layer (crosslinked surface) is obtained by conventional ultraviolet irradiation and LED light irradiation as shown below. The problem is that the problem in forming the layer is avoided.
That is, conventionally, the crosslinked surface layer is formed by applying a surface layer coating solution (coating solution) containing at least a radical polymerizable compound and a solvent onto the photosensitive layer, and then irradiating the coating film with light energy, mainly ultraviolet rays. However, there is a problem that the rate of cross-linking reaction due to oxygen inhibition is reduced due to the presence of oxygen during irradiation of light energy using an LED as a light source. Hardening failure due to oxygen inhibition can be improved by purging with nitrogen, but slightly remaining oxygen is fixed to the surface layer, which causes abnormal images.

On the other hand, the LED light source used for light energy irradiation in the present invention, unlike a general ultraviolet lamp, can emit desired single-wavelength light, and therefore generates an active gas such as ozone. It has been said to be suppressed. Furthermore, since it is very compact and the cooling mechanism is simple, there is an advantage that the installation location is not limited. Accordingly, the LED can be turned on by installing it in a vacuum chamber together with the photosensitive drum, and in addition, according to the present invention, it is possible to cause a crosslinking reaction in a very low oxygen concentration.
Next, the LED light source used for light energy irradiation in the present invention will be described.
In general, as a light source for generating radicals in a radically polymerizable compound by irradiating light energy, an electroded lamp represented by a high pressure mercury lamp or a metal halide lamp, or an electrodeless material that emits light by exciting a luminescent substance with microwave energy There is a lamp. As described above, the emission wavelength of these ultraviolet lamps is mainly 400 nm or less, but also includes a lot of light having a wavelength of 400 nm or more, and the wavelength at which the initiator generates radicals even with light having a wavelength of 400 nm or less. Light outside the area is also included. In other words, the absorption of light in these unnecessary wavelength regions causes the temperature of the substrate to be irradiated to rise, resulting in surface irregularities during curing, or the internal stress of the surface layer increases due to a rapid crosslinking reaction. This causes peeling of the layer.
In addition, when the radical polymerizable compound (b) having a charge transporting structure as in the present invention is contained as a radical polymerizable compound, the radical polymerizable compound in which a specific wavelength light of the ultraviolet lamp has a charge transporting structure. It will cause (B) to decompose.
There are an infrared cut filter and an ultraviolet cut filter for cutting the unnecessary wavelength light of the ultraviolet lamp, but it is very difficult to efficiently transmit only the necessary wavelength light with a single filter. . For cutting light exceeding 400 nm, a filter that absorbs long-wavelength light such as an infrared cut filter is used. However, in this case, the filter becomes hot due to heat, and the filter is cracked and cannot be practically used.
In general, a large amount of electrical energy is required to cause the ultraviolet lamp to emit light, and a cooling device such as a blower is necessary for cooling the ultraviolet lamp. There is a drawback that the installation location is limited due to the enlargement of the apparatus.

On the other hand, the LED light source used in the present invention can emit only light in the wavelength region necessary for the initiator to generate radicals. It can be set as the light source which does not contain the ultraviolet-ray which decomposes | disassembles the radically polymerizable compound (b) which has a crystalline structure. Furthermore, the LED light source is very small and is not limited by the installation location. In addition, while a general ultraviolet lamp is driven by an AC power source and periodically emits light, an LED light source is driven by a DC power source and continuously emits light, so that the surface of the film in the surface layer and the internal cured state are There is a merit that it becomes uniform and so-called cross-linking uniformity is improved, but on the other hand, no countermeasure for suppressing active gas such as ozone has been taken.
The LED light source used in the present invention is an LED element having a light emission wavelength mainly in the ultraviolet region, and materials used for the light emitting element include indium gallium nitride, gallium nitride, aluminum gallium nitride, and the like. In addition to the LED element having a lamp shape, the LED element is embedded in a chip as a chip, and the light emitted from each element is condensed to increase the illuminance.

  In the present invention, the LED irradiation unit is installed in a vacuum chamber together with the photosensitive drum, and is cured by irradiation. As the shape of the apparatus, for example, [1] a method in which an LED irradiation unit and a photosensitive drum are simultaneously installed in a vacuum chamber and pressure is reduced while an inert gas is injected on the other side (FIG. 1); 2] A method (FIG. 2) or the like in which the gas replacement efficiency is increased by injecting an inert gas having a specific gravity smaller than oxygen from above while reducing the pressure.

1 and 2, reference numeral (1) is a vacuum chamber, reference numeral (2) is a conductive support (photosensitive drum), reference numeral (3) is an LED-UV irradiation unit, reference numeral (4) is a decompression port, reference numeral (5) indicates an inert gas inlet.
A vacuum pump is used as a method for reducing the pressure in the vacuum chamber. A rotary pump is most commonly used to obtain a vacuum of about 1 to 10 ⁻² mmHg, and a diffusion pump is used to obtain a high vacuum of 10 ⁻³ mmHg or less.
In addition, since it is possible to prevent the generation of infrared rays that cause heat generation when light energy is emitted from an LED light source, it is not necessary to cool the photosensitive drum during light energy irradiation.

Next, the constituent material of the surface layer coating solution (surface layer coating solution) containing the radical polymerizable compound used for forming the surface layer in the present invention will be described.
As the radical polymerizable compound in the present invention, it is preferable to use a radical polymerizable monomer (A) having no charge transporting structure and / or a radical polymerizable compound (B) having a charge transporting structure.
Hereinafter, the radically polymerizable monomer (A) having no charge transporting structure and the radically polymerizable compound (B) having a charge transporting structure will be described in detail.

[Radically polymerizable monomer having no charge transport structure (A)]
Examples of the radically polymerizable monomer (a) having no charge transport structure used in the present invention include hole transport structures such as triarylamine, hydrazone, pyrazoline and carbazole, and examples thereof include condensed polycyclic quinones and diphenoquinones. And a monomer having no electron transport structure such as an electron-withdrawing aromatic ring having a cyano group or a nitro group.

The radical polymerizable functional group may be any group that 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) As 1-substituted ethylene functional group, the functional group represented by following General formula (1) is mentioned, for example.

［ただし、一般式（１）中、Ｘ２は、置換基を有していてもよいアリーレン基、置換基を有していてもよいアルケニレン基、−ＣＯ−基、−ＣＯＯ−基、−ＣＯＮＲ３６−基〔Ｒ３６は、水素、アルキル基、アラルキル基、アリール基を表す。〕、または−Ｓ−基を表す。］

[In the general formula (1), X2 represents an arylene group which may have a substituent, an alkenylene group which may have a substituent, a —CO— group, a —COO— group, a —CONR36— Group [R36 represents hydrogen, an alkyl group, an aralkyl group, or an aryl group. Or -S- group. ]

Specific examples of the arylene group which may have a substituent include a phenylene group, a naphthylene group, and the like. Also, as an alkyl group in R36, a methyl group, an ethyl group, and the like are used, and as an aralkyl group, a benzyl group is used. , Naphthylmethyl group, phenethyl group and the like, and aryl groups include phenyl group, naphthyl group and the like.
Specific examples of these substituents include vinyl group, styryl group, 2-methyl-1,3-butadienyl group, vinylcarbonyl group, acryloyloxy group, acryloylamide group, vinylthioether group and the like.

  (2) Examples of the 1,1-substituted ethylene functional group include functional groups represented by the following general formula (2).

［ただし、一般式（２）中、Ｙ４は、置換基を有していてもよいアルキル基、置換基を有していてもよいアラルキル基、置換基を有していてもよいアリール基、ハロゲン原子、シアノ基、ニトロ基、アルコキシ基または、−ＣＯＯＲ３７基〔Ｒ３７は、水素原子、置換基を有していてもよいアルキル基、置換基を有していてもよいアラルキル基、置換基を有していてもよいアリール基、または−ＣＯＮＲ３８Ｒ３９（Ｒ３８およびＲ３９は、水素原子、置換基を有していてもよいアルキル基、置換基を有していてもよいアラルキル基、または置換基を有していてもよいアリール基を表し、互いに同一または異なっていてもよい。）を表す。〕を表し、また、Ｘ３は上記一般式（１）のＸ２と同一の基および単結合、アルキレン基を表す。ただし、Ｙ４、Ｘ３の少なくとも何れか一方がオキシカルボニル基、シアノ基、アルケニレン基、および芳香族環よりなる群から選ばれた基である。］

[In the general formula (2), Y4 represents 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 halogen, Atom, cyano group, nitro group, alkoxy group, or -COOR37 group [R37 has a hydrogen atom, an alkyl group that may have a substituent, an aralkyl group that may have a substituent, or a substituent. An optionally substituted aryl group, or —CONR38R39 (R38 and R39 each have a hydrogen atom, an alkyl group that may have a substituent, an aralkyl group that may have a substituent, or a substituent. Represents an aryl group which may be, and may be the same or different from each other. X3 represents the same group as X2 in the general formula (1), a single bond, or an alkylene group. However, at least one of Y4 and X3 is a group selected from the group consisting of an oxycarbonyl group, a cyano group, an alkenylene group, and an aromatic ring. ]

Specific examples of the alkyl group that may have a substituent in Y4 include a methyl group and an ethyl group, and the aralkyl group that may have a substituent includes a benzyl group and a phenethyl group. Examples of the aryl group which may have a phenyl group and a naphthyl group include an methoxy group and an ethoxy group. In addition, as the alkyl group which may have a substituent in R37, a methyl group, an ethyl group or the like, and as the aralkyl group which may have a substituent, a benzyl group, a phenethyl group or the like has a substituent. Examples of the aryl group that may be used include a phenyl group and a naphthyl group.
Further, the alkyl group which may have a substituent in R38 and R39 is a methyl group, an ethyl group or the like, and the aralkyl group which may have a substituent is a benzyl group, a naphthylmethyl group or a phenethyl group, etc. However, examples of the aryl group which may have a substituent include a phenyl group and a naphthyl group.

  Specific examples of these substituents include an α-acryloyloxy group, a methacryloyloxy group, an α-cyanoethylene group, an α-cyanoacryloyloxy group, an α-cyanophenylene group, and a methacryloylamino group.

Examples of the substituent further substituted on the groups X2, X3, and Y4 include, for example, halogen groups, nitro groups, alkyl groups such as cyano groups, methyl groups, and ethyl groups, alkoxy groups such as methoxy groups and ethoxy groups, Examples thereof include aryloxy groups such as phenoxy group, aryl groups such as phenyl group and naphthyl group, aralkyl groups such as benzyl group and phenethyl group.
Among these radical polymerizable functional groups, acryloyloxy group and methacryloyloxy group are particularly useful.

The number of functional groups of the radically polymerizable monomer (a) having no charge transporting structure is not particularly limited, but if a large amount of monofunctional and bifunctional radically polymerizable monomers and radically polymerizable oligomers are contained, the surface layer is three-dimensionally crosslinked. Since the bond density is substantially lowered and the wear resistance is lowered, the content of these monomers and oligomers is 50 parts by weight or less, preferably 30 parts by weight with respect to 100 parts by weight of a tri- or higher functional radical polymerizable monomer. Limited to less than
Specific examples of the radical polymerizable monomer (A) having no charge transport structure include the following, but are not limited to these compounds.

  That is, examples of the radical polymerizable monomer (A) used in the present invention include stearyl acrylate, tetrahydrofurfuryl acrylate, lauryl acrylate, 2-phenoxy acrylate, tridecyl acrylate, caprolactone acrylate, EO-modified nonylphenyl acrylate, Bonyl acrylate, tetrahydrofurfuryl methacrylate, lauryl methacrylate, stearyl methacrylate, 2-phenoxyethyl methacrylate, isobornyl methacrylate, PO-modified allyl methacrylate, EO-modified hydroxyethyl methacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol Diacrylate, diethylene glycol diacrylate, 1,6-hexanediol dia Relate, neopentyl glycol diacrylate, tetraethylene glycol diacrylate, triethylene glycol diacrylate, tripropylene glycol diacrylate, EO-modified bisphenol A diacrylate, cyclohexane dimethanol diacrylate, dipropylene glycol diacrylate, PO-modified neopentyl glycol Diacrylate, EO-modified bisphenol A dimethacrylate, triethylene glycol dimethacrylate, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,4 butanediol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol Dimethacrylate, neopentyling Cold dimethacrylate, 1,3-butylene glycol dimethacrylate, cyclohexanedimethanol dimethacrylate, trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, HPA modified trimethylolpropane triacrylate, EO modified trimethylolpropane triacrylate, PO modified trimethylolpropane triacrylate, caprolactone modified trimethylolpropane triacrylate, HPA modified trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol triacrylate, ECH modified glycerol triacrylate, EO modified glycerol Triacrylate, P O-modified glycerol triacrylate, tris (acryloxyethyl) isocyanurate, dipentaerythritol hexaacrylate (DPHA), caprolactone-modified dipentaerythritol hexaacrylate, dipentaerythritol hydroxypentaacrylate, alkyl-modified dipentaerythritol pentaacrylate, alkyl-modified di Pentaerythritol tetraacrylate, alkyl-modified dipentaerythritol triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, EO-modified phosphate triacrylate, 2,2,5,5-tetrahydroxymethylcyclopentanone tetra Acrylate, etc., and these may be used alone or in combination of two or more. No problem even if the.

[Radically polymerizable compound having a charge transporting structure (b)]
Examples of the radically polymerizable compound (b) having a charge transporting structure used in the present invention include a hole transporting structure such as triarylamine, hydrazone, pyrazoline, carbazole, and the like, for example, condensed polycyclic quinone, diphenoquinone, A compound having an electron transport structure such as an electron-withdrawing aromatic ring having a cyano group or a nitro group and having a radical polymerizable functional group. Examples of the radical polymerizable functional group include the groups described above for the radical polymerizable monomer (a), and acryloyloxy group and methacryloyloxy group are particularly useful.

  In addition, as the radically polymerizable compound (b) having a charge transporting structure (roughly, “charge transporting compound”), a polyfunctional compound having two or more functional groups can be used. In terms of electrostatic characteristics, monofunctional ones are preferred. The reason why monofunctional is preferable is that when a charge transporting compound having two or more functions is used, the charge transporting compound is fixed in the crosslinked structure by a plurality of bonds, and the charge transporting structure is very bulky at that time. For this reason, distortion occurs in the cured resin, the internal stress of the surface layer increases, and it becomes easy to cause cracks and scratches due to carrier adhesion and the like. When the surface layer has a thickness of 5 μm or less, there is no particular problem. However, when a film exceeding 5 μm is formed, the internal stress of the surface layer becomes very high, and cracks are likely to occur immediately after crosslinking.

In addition, in terms of electrostatic characteristics, when a bifunctional or higher functional charge transport compound is used, the intermediate structure (cation radical) during charge transport is stable because it is fixed in the crosslinked structure by a plurality of bonds. However, it is easy to cause a decrease in sensitivity and an increase in residual potential due to charge trapping.
Such deterioration of the electrical characteristics appears as an image such as a decrease in image density and thinning of characters.
For this reason, as the radical polymerizable compound (b) having a charge transporting structure, a radical polymerizable compound having a monofunctional charge transporting structure is used, and is immobilized in a pendant shape between crosslinks. In addition, cracks and scratches can be prevented and electrostatic characteristics can be stabilized.

As a charge transporting structure, a high effect is obtained when a triarylamine structure is used.
In addition, those having one functional group are preferable, and when a compound represented by the structure of the following general formula (3) or the following general formula (4) is used, the electrical characteristics such as sensitivity and residual potential are good. To last.

[In the formulas (3) and (4), R1 is a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or an aryl which may have a substituent. Group, cyano group, nitro group, alkoxy group, -COOR7 [R7 is a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent or an aryl which may have a substituent. Represents a group selected from the group consisting of groups. ], A carbonyl halide group or CONR8R9 [wherein R8 and R9 are a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or an aryl which may have a substituent Represents a group selected from the group consisting of groups, and both may be the same or different. ] Represents a group selected from the group consisting of: Ar 1 and Ar 2 represent an arylene group which may have a substituent, and may be the same or different. Ar3 and Ar4 represent an aryl group which may have a substituent, and both may be the same or different. X is composed of a single bond, an alkylene group which may have a substituent, a cycloalkylene group which may have a substituent, an alkylene ether group which may have a substituent, an oxygen atom, a sulfur atom or a vinylene group. Z is a group selected from the group, Z is a group selected from the group consisting of an alkylene group which may have a substituent, an alkylene ether group which may have a substituent, and an alkyleneoxycarbonyl group, m , N represents an integer of 0-3. ]

Specific examples of the compounds represented by the structures of general formula (3) and general formula (4) are shown below.
In the general formulas (3) and (4), in the substituent of R1, 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, a naphthylmethyl group, and the like, 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 an alkyl group. Groups (such as methyl and ethyl groups), alkoxy groups (such as methoxy and ethoxy groups), aryloxy groups (such as phenoxy groups), aryl groups (such as phenyl and naphthyl groups), aralkyl groups (such as benzyl and phenethyl groups) ) Or the like. Among the substituents for R1, a hydrogen atom or a methyl group is particularly preferable.

Ar3 and Ar4 represent an aryl group which may have a substituent. In the present invention, examples of the aryl group include a condensed polycyclic hydrocarbon group, a non-fused 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-indacenyl group. , S-indacenyl group, fluorenyl group, acenaphthylenyl group, preadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrenyl group, aceanthrylenyl group, triphenylyl group, pyrenyl group , A chrycenyl group, a naphthacenyl group, and the like.

  Examples of the non-condensed 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 rings such as 9,9-diphenylfluorene Examples thereof include monovalent groups of aggregated hydrocarbon compounds.

Examples of the heterocyclic group include monovalent groups such as carbazole, dibenzofuran, dibenzothiophene, oxadiazole, and thiadiazole.
Moreover, the aryl group represented by Ar3 and Ar4 may have a substituent as shown below, for example.
[1] Halogen atom, cyano group, nitro group and the like.

[2] An alkyl group. Preferably, it is a C1-C12, particularly C1-C8, more preferably a C1-C4 linear or branched alkyl group, and these alkyl groups further include a fluorine atom, a hydroxyl group, a cyano group, and a C1-C4 alkoxy group. , A phenyl group or a halogen atom, a C1-C4 alkyl group, or a phenyl group substituted with a C1-C4 alkoxy group. Specific examples are 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-ethoxy. Examples include ethyl group, 2-cyanoethyl group, 2-methoxyethyl group, benzyl group, 4-chlorobenzyl group, 4-methylbenzyl group, 4-phenylbenzyl group and the like.

[3] Alkoxy group (—OR2) [R2 represents an alkyl group defined in the above [2]].
Specific examples thereof include 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, trifluoromethoxy group and the like.

[4] Aryloxy group. Examples of the aryl group include a phenyl group and a naphthyl group.
This may contain a C1-C4 alkoxy group, a C1-C4 alkyl group or a halogen atom 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] Alkyl mercapto group or aryl mercapto group. Specific examples include methylthio group, ethylthio group, phenylthio group, p-methylphenylthio group and the like.
[6] Examples include groups represented by the following general formula (a).

［式（ａ）中、Ｒ３およびＲ４は各々独立に水素原子、前記〔２〕で定義したアルキル基、またはアリール基を表す。アリール基としては、例えば、フェニル基、ビフェニル基またはナフチル基が挙げられ、これらはＣ１〜Ｃ４のアルコキシ基、Ｃ１〜Ｃ４のアルキル基またはハロゲン原子を置換基として含有してもよい。Ｒ３およびＲ４は共同で環を形成してもよい。］

[In Formula (a), R3 and R4 each independently represent 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, and these may contain a C1 to C4 alkoxy group, a C1 to C4 alkyl group, or a halogen atom as a substituent. R3 and R4 may form a ring together. ]

Specific examples include 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 styryl group which may have a substituent, a β-phenylstyryl group which may have a substituent, a diphenylaminophenyl group, a ditolylaminophenyl group and the like.
Examples of the arylene groups represented by Ar1 and Ar2 include divalent groups derived from the aryl groups represented by Ar3 and Ar4.
X represents a single bond, an alkylene group which may have a substituent, a cycloalkylene group which may have a substituent, an alkylene ether group which may have a substituent, an oxygen atom, a sulfur atom or a vinylene group. To express.
The alkylene group which may have a substituent is a C1-C12, preferably C1-C8, more preferably a C1-C4 linear or branched alkylene group, and these alkylene groups further include a fluorine atom. , A hydroxyl group, a cyano group, a C1-C4 alkoxy group, a phenyl group or a halogen atom, a C1-C4 alkyl group, or a phenyl group substituted with a C1-C4 alkoxy group.
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-ethoxy. Examples include ethylene 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 C5-C7 cyclic alkylene group, and these cyclic alkylene groups have a fluorine atom, a hydroxyl group, a C1-C4 alkyl group, and a C1-C4 alkoxy group. May be. Specific examples include a cyclohexylidene group, a cyclohexylene group, and a 3,3-dimethylcyclohexylidene group.
Examples of the alkylene ether group which may have a substituent include ethyleneoxy, propyleneoxy, ethylene glycol, propylene glycol, diethylene glycol, tetraethylene glycol and tripropylene glycol. The alkylene ether group, the alkylene group is a hydroxyl group, methyl May have a substituent such as a group or an ethyl group.
Examples of the vinylene group include groups represented by the following general formulas (b) and (c).

［式（ｂ）、（ｃ）中、Ｒ５は水素、アルキル基（前記〔２〕で定義されるアルキル基と同じ〕、アリール基（前記Ａｒ３、Ａｒ４で表わされるアリール基と同じ）、ａは１または２、ｂは１〜３の整数を表す。）

[In the formulas (b) and (c), R5 is hydrogen, an alkyl group (the same as the alkyl group defined in [2] above), an aryl group (the same as the aryl group represented by Ar3 or Ar4), and a is 1 or 2, b represents an integer of 1 to 3)

  In the general formulas (3) and (4), Z represents an alkylene group which may have a substituent, an alkylene ether group which may have a substituent, or an alkyleneoxycarbonyl group. Examples of the alkylene group that may have a substituent include those similar to the alkylene group of X. Examples of the alkylene ether group that may have a substituent include the alkylene ether group of X. Examples of the alkyleneoxycarbonyl group include caprolactone-modified groups.

  Moreover, as a more preferable compound as the radically polymerizable compound (b) having a monofunctional charge transport structure of the present invention, a compound having a structure represented by the following general formula (5) can be mentioned.

［式（５）中、ｏ、ｐ、ｑはそれぞれ０または１の整数、Ｒａは水素原子、メチル基を表し、Ｒｂ、Ｒｃは水素原子以外の置換基で炭素数１〜６のアルキル基を表し、ＲｂとＲｃは同一であっても異なっていてもよく、ｓ、ｔは０〜３の整数を表し、Ｚａは単結合、メチレン基、エチレン基、あるいは下記式（ｄ）、（ｅ）、（ｆ）で表される二価基よりなる群から選ばれた基を表す。］

[In the formula (5), 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. Rb and Rc may be the same or different, s and t each represent an integer of 0 to 3, Za is a single bond, a methylene group, an ethylene group, or the following formulas (d) and (e) , (F) represents a group selected from the group consisting of divalent groups. ]

  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.

  In the radically polymerizable compound (b) having a monofunctional charge transport structure described in the above general formulas (3) and (4) and (5) used in the present invention, the carbon-carbon double bond is open on both sides. Therefore, in the polymer that is incorporated into the chain polymer and crosslinked by polymerization with the radical polymerizable monomer (a), it does not form a terminal structure and exists in the main chain of the polymer. And present in a cross-linked chain between the main chain and the main chain (this cross-linked chain includes an intermolecular cross-linked chain between one polymer and another polymer, and a main chain folded in one polymer. There is an intramolecular cross-linked chain that crosslinks a certain part of the main chain and another part derived from the polymerized monomer at a position away from this in the main chain), but even if it exists in the main chain, Even when present in the bridging chain, the triarylamine structure suspended from the chain moiety is It has at least three aryl groups arranged radially from the elementary atoms and is bulky, but it is not directly bonded to the chain part and is suspended from the chain part via a carbonyl group, etc. It is fixed in a flexible state. As a result, these triarylamine structures can be arranged adjacent to each other in the polymer, so that there is little structural distortion in the molecule, and when the surface layer of the electrophotographic photoreceptor is used. Therefore, it is presumed that an intramolecular structure relatively free from the interruption of the charge transport pathway can be adopted.

  In addition, the radical polymerizable compound (b) having a charge transport structure used in the present invention can be used when the charge transport performance of the lower layer can be utilized by adjusting the thickness of the surface layer (making it a very thin film). Although it is possible to adopt a configuration that is not used as an essential component, it is usually important for imparting charge transport performance of the surface layer, and this component is 20 to 80% by weight, preferably 30 to 30% by weight based on the total amount of the surface layer. 70% by weight. If this component is less than 20% by weight, the charge transport performance of the surface layer cannot be sufficiently maintained, and deterioration of electrical characteristics such as a decrease in sensitivity and an increase in residual potential appear with repeated use. On the other hand, if it exceeds 80% by weight, the content of the radical polymerizable monomer having no charge transport structure is lowered, the density of the cross-linking bond is lowered, and high wear resistance is not exhibited. The required electrical characteristics and wear resistance differ depending on the process to be used, so it cannot be said unconditionally, but considering the balance of both characteristics, the range of 30 to 70% by weight is most preferable.

  The surface layer of the present invention is formed by curing at least a radically polymerizable compound by light energy irradiation using an LED as a light source while controlling the temperature of the conductive support. In order to advance the reaction efficiently, a polymerization initiator may be used. That is, after a polymerization initiator is contained in the surface layer coating liquid to form a coating film, it may be cured by irradiating LED light while controlling the temperature of the conductive support.

Examples of the polymerization 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-methyl Acetophenone-based or ketal-based photopolymerization initiators such as 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, 1 Benzophenone photopolymerization initiators such as 2-benzoylbenzene, thioxanthones such as 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone A photoinitiator is mentioned.
Other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, and bis (2,4,6-trimethylbenzoyl). Phenylphosphine oxide, bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10-phenanthrene, acridine compounds, triazine compounds, imidazole compounds, Can be mentioned.

Moreover, what has a photopolymerization acceleration effect can also be used individually or in combination with the said photoinitiator. Examples thereof include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, 4,4′-dimethylaminobenzophenone, and the like.
It is important to use those polymerization initiators that generate radicals with the wavelength light of the LED light source.
The addition amount of these polymerization initiators is 0.5-40 weight part with respect to 100 weight part of radically polymerizable compounds, Preferably it is 1-20 weight part.

  Furthermore, the surface layer coating liquid (substantially, “coating liquid”) used in the present invention does not have various plasticizers (for the purpose of stress relaxation and adhesion improvement), leveling agents, and radical reactivity as necessary. Additives such as low molecular charge transport materials can be included. Known additives can be used for these additives. As the plasticizer, those used in general resins such as dibutyl phthalate and dioctyl phthalate can be used, and the amount used is 20% by weight or less, preferably 10% by weight, based on the total solid content of the coating liquid. It is suppressed to the following. As leveling agents, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers having a perfluoroalkyl group in the side chain, or oligomers can be used, and the amount used is the total solid content of the coating liquid. 3% by weight or less is appropriate.

  The surface layer in the electrophotographic photoreceptor of the present invention is formed by applying a coating solution containing at least a radical polymerizable compound and curing the formed coating film. 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.

  Examples of materials used in the surface layer coating liquid (coating liquid) for forming the surface layer of the present invention will be given and the coating method will be exemplified. For example, when an acrylate monomer having three acryloyloxy groups and a triarylamine compound having one acryloyloxy group are used as the coating liquid, the usage ratio thereof is 7: 3 to 3: 7. The polymerization initiator is added in an amount of 3 to 20% by weight based on the total amount of these acrylate compounds, and a solvent is further added to prepare a coating solution. For example, in the case where the surface layer is formed by spray coating in the charge transport layer which is the lower layer of the surface layer, using a triarylamine donor as the charge transport material and polycarbonate as the binder resin, the solvent of the coating solution As for, tetrahydrofuran, 2-butanone, ethyl acetate, etc. are preferable, and the usage-amount is 3 times amount-10 times amount with respect to the acrylate compound whole quantity.

Next, for example, the prepared coating solution is applied by spraying or the like onto an electrophotographic photosensitive member in which an undercoat layer, a charge generation layer, and a charge transport layer are sequentially laminated on a support such as an aluminum cylinder.
Thereafter, it is dried at a relatively low temperature for a short time (20 to 80 ° C., 1 to 10 minutes) and cured by irradiation with light energy. After the curing is completed, the electrophotographic photosensitive member is obtained by heating at 100 to 150 ° C. for 10 to 30 minutes in order to remove the residual solvent and the residual initiator and stabilize the surface film.
Hereinafter, the electrophotographic photosensitive member in the present invention will be described according to its layer structure.

[Layer structure of electrophotographic photosensitive member]
The electrophotographic photosensitive member of the present invention will be described with reference to the drawings.
FIG. 3 is a schematic cross-sectional view showing an example of the layer structure of the electrophotographic photosensitive member in the present invention. In the electrophotographic photoreceptor of FIG. 3, a photosensitive layer (33) having a single layer structure having a charge generating function and a charge transporting function is provided on a conductive support (31), and further on the photosensitive layer (33). It has a configuration in which a crosslinked surface layer (surface layer) (39) is formed.
FIG. 4 is a schematic cross-sectional view showing another example of the layer structure of the electrophotographic photosensitive member in the present invention. In the electrophotographic photosensitive member of FIG. 4, a laminate in which a charge generation layer (35) having a charge generation function and a charge transport layer (37) having a charge transport function are stacked on a conductive support (31). The structure is such that a crosslinked surface layer (surface layer) (39) is formed on the photosensitive layer having the structure.

[Conductive support]
As the conductive support (31), a material having a volume resistance of 10 ¹⁰ Ω · cm or less, for example, a metal such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, oxidation Metal oxide such as indium is deposited or sputtered to form film or cylindrical plastic, paper coated, or aluminum, aluminum alloy, nickel, stainless steel, etc. After conversion, a tube that has been subjected to surface treatment such as cutting, superfinishing, or polishing can be used. Further, endless nickel belts and endless stainless steel belts disclosed in JP-A-52-36016 can also be used as the conductive support.

In addition, those obtained by dispersing and coating conductive powder in an appropriate binder resin on the support can also be used as the conductive support of the present invention.
Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc and silver, or metal oxide powder such as conductive tin oxide and ITO. Can be mentioned. The binder resin used at the same time is polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. , Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, Examples thereof include thermoplastic, thermosetting resins, and photocurable resins such as melamine resin, urethane resin, phenol resin, and alkyd resin.
Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.

  Furthermore, it is electrically conductive by a heat-shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, 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.

[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 a layer having a charge generation function and a charge transport function at the same time.
Each of the photosensitive layer having a laminated structure and the photosensitive layer having a single layer structure will be described below.

[Photosensitive layer having a laminated structure]
(Charge generation layer)
The charge generation layer [for example, the charge generation layer (35) shown in FIG. 4] is a layer mainly composed of a charge generation compound having a charge generation function, and a binder resin can be used in combination as necessary. As the charge generation compound, 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 Indigoid pigments, and bisbenzimidazole pigments. Of these, phthalocyanines are particularly useful. Among them, titanyl phthalocyanine, particularly, the main peak of Bragg angle 2θ in the X-ray diffraction spectrum for at least Cu-Kα ray is at least 9.6 ° ± 0.2 °, 24 Y-type titanyl phthalocyanine having a crystal form of 0.0 ° ± 0.2 ° and 27.2 ° ± 0.2 ° is particularly effective as a highly sensitive material. These charge generation compounds 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.

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 transport 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- Examples thereof include electron-accepting substances such as trinitrodibenzothiophene-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 following electron donating materials 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.

As a method for forming the charge generation layer, a vacuum thin film preparation method and a casting method from a solution dispersion system can be largely mentioned.
For the former method, vacuum evaporation method, glow discharge decomposition method, ion plating method, sputtering method, reactive sputtering method, CVD method, etc. are used, and the above-mentioned inorganic materials and organic materials are used to generate charges. A layer can be formed satisfactorily.
In addition, in order to provide a charge generation layer by the casting method described later, if necessary, the inorganic or organic charge generation compound described above together with a binder resin, tetrahydrofuran, dioxane, dioxolane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, cyclohexane. Disperse 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. A layer can be formed. 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.

[Charge transport layer]
The charge transport layer [for example, the charge transport layer (37) shown in FIG. 4] is a layer having a charge transport function. In the present invention, a surface layer [for example, the crosslinked surface layer (39) shown in FIG. 4] is formed on the charge transport layer. ] Is formed.
The charge transport layer is formed by dissolving or dispersing at least a charge transport material having a charge transport function and a binder resin in an appropriate solvent, and applying and drying the solution on the charge generation layer. A radically polymerizable composition and a coating solution containing a filler as required are applied, and the formed coating film is crosslinked and cured by light energy using an LED as a light source while controlling the temperature of the conductive support. Let The thickness of the charge transport layer is suitably about 5 to 40 μm, preferably about 10 to 30 μm.

  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.

  Binder resins include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, poly Vinylidene 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, Examples thereof include thermoplastic or thermosetting resins such as phenol resins and alkyd resins.

  As the solvent used for coating the charge transport layer, the same solvent as the charge generation layer can be used, but a solvent that dissolves the charge transport material and the binder resin well is suitable. These solvents may be used alone or in combination of two or more. The charge transport layer can be formed by the same coating method as that for the charge generation layer. If necessary, a plasticizer and a leveling agent can be added.

  As 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 to 100 parts by weight of the binder resin. About 30 parts by weight is appropriate.

  Examples of leveling agents that can be used in 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. About 0 to 1 part by weight is appropriate for the part by weight.

  As described in the surface layer preparation method described above, a coating liquid containing the radical polymerizable composition of the present invention is applied onto the charge transport layer, and the formed coating film is dried as necessary, and then conductive. While controlling the temperature of the conductive support, the curing reaction is started by irradiation of light energy from the LED light source, and a surface layer is formed. At this time, the film thickness of the surface layer is 1 to 20 μm, preferably 2 to 10 μm. If the thickness is less than 1 μm, the durability varies due to uneven film thickness. If the thickness is more than 20 μm, the entire thickness of the charge transport layer is increased, and the reproducibility of the image is reduced due to the diffusion of charges.

[Photosensitive layer is a single layer]
A photosensitive layer having a single layer structure is a layer having both a charge generation function and a charge transport function. In the present invention, a surface layer is formed on the photosensitive layer.
The photosensitive layer [for example, photosensitive layer (33) shown in FIG. 3] is obtained by dissolving or dispersing a charge generating compound having a charge generating function, a charge transporting material having a charge transporting function, and a binder resin in an appropriate solvent, and coating the solution. It can be formed by drying. Moreover, a plasticizer, a leveling agent, etc. can also be added as needed. The description of the charge generation compound dispersion method and the charge generation compound, charge transport material, plasticizer, and leveling agent can be applied as they have been described in the charge generation layer and 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. The film thickness of the photosensitive layer is suitably about 5 to 30 μm, preferably about 10 to 25 μm.
As described above, a coating solution containing the radical polymerizable compound of the present invention and a charge generating compound is applied to the photosensitive layer, and the formed coating film is dried as necessary, and then the temperature of the conductive support is adjusted. While controlling, the curing reaction is started by irradiation of light energy from the LED light source, and a surface layer is formed. At this time, the film thickness of the surface layer is 1 to 20 μm, preferably 2 to 10 μm. When the thickness is less than 1 μm, the durability varies due to the film thickness unevenness.

  The charge generating compound contained in the photosensitive layer having a single layer structure is preferably 1 to 30% by weight based on the total amount of the photosensitive layer, the binder resin contained in the photosensitive layer is 20 to 80% by weight, and the charge transporting substance is 10%. ~ 70 parts by weight are used favorably.

[Underlayer]
In the electrophotographic 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, for the undercoat layer of the present invention, a vacuum thin film is formed of Al2O3 provided by anodic oxidation, organic substances such as polyparaxylylene (parylene), and inorganic substances such as SiO2, SnO2, TiO2, ITO, CeO2 Those provided by the law can also be used satisfactorily. 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]
In addition, in the present invention, in order to improve environmental resistance, in order to prevent a decrease in sensitivity and an increase in residual potential, oxidation is prevented in each layer such as a surface layer, a charge generation layer, a charge transport layer, and an undercoat layer. An agent can be added.
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 ] Glycol esters, 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 phosphorus compounds)
Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine, and the like.
These compounds are known as antioxidants such as rubbers, plastics and fats and oils, and commercially available products can be easily obtained.
The addition amount of the antioxidant in the present invention is 0.01 to 10% by weight based on the total weight of the layer to be added.

<Image Forming Method and Apparatus>
Next, the image forming method and the image forming apparatus of the present invention will be described in detail with reference to the drawings.
The image forming method and the image forming apparatus of the present invention use a photoconductor having a smooth charge transporting surface layer. For example, at least after the photoconductor is charged, exposed to an image, and developed, an image holding body is used. An image forming method and an image forming apparatus including a process of transferring a toner image onto (transfer paper), fixing, and cleaning of the surface of a 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. 5 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 this light source, all luminescent materials such as fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light emitting diodes (LEDs), semiconductor lasers (LD), and 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, as means for applying a lubricant to the photoreceptor in order to improve toner releasability on the surface of the photoreceptor, there are a lubricant application roller (16), a lubricant (17), and a lubricant application blade (18). A fatty acid metal salt or the like is used as the lubricant.

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.

Hereinafter, the present invention will be described with reference to examples and comparative examples, but the present invention is not limited thereto.
(Emission wavelength measurement)
The wavelength spectrum of the LED light source was measured in the range of 350 nm to 400 nm using an optical spectrum analyzer Q8381A (manufactured by Advantest).
(Synthesis of compounds having a charge transporting structure)
The compound having a charge transporting structure in the present invention is synthesized, for example, by a known method described in Japanese Patent No. 3164426.

An undercoat layer was formed on an Al support (outer diameter 100 mmφ) by dipping so that the film thickness after drying was 4.5 μm.
<Coating liquid for undercoat layer>
Alkyd resin 6.5 parts (Beccosol 1307-60-EL, manufactured by Dainippon Ink & Chemicals, Inc.)
Melamine resin 3.5 parts (Super Becamine G-821-60, manufactured by Dainippon Ink & Chemicals, Inc.)
Titanium oxide 60 parts (CR-EL: Ishihara Sangyo)
90 parts of methyl ethyl ketone A charge generation layer coating solution containing a titanyl phthalocyanine pigment was dip-coated on this undercoat layer and dried by heating to form a charge generation layer having a thickness of 0.3 μm.

<Coating liquid for charge generation layer>
Y-type titanyl phthalocyanine pigment 2.5 parts Polyvinyl butyral (BX-1, manufactured by Sekisui Chemical Co., Ltd.) 0.5 parts Methyl ethyl ketone 100 parts Dipping coating is carried out on the charge generation layer using the coating liquid for charge transport layer having the following structure. And dried by heating to obtain a charge transport layer having a thickness of 15 μm.

<Coating liquid for charge transport layer>
9 parts of bisphenol Z type polycarbonate 9 parts of the following charge transport compound

Spray coating was performed on the charge transport layer using a surface layer forming coating solution having the following constitution. An electrophotographic photosensitive drum is attached to an apparatus as shown in FIG. 2, and N ₂ gas (density 1.2506 kg / m ³ (0 ° C., 1 atm)) is injected into the vacuum chamber while reducing the pressure with a rotary pump. Light irradiation was performed by an LED light source (manufactured by Eye Graphics). This LED light source has an emission peak only at a wavelength of 365 nm (see FIG. 6). The light intensity on the surface of the photoconductive drum is 300 mW / cm ² , light irradiation is performed while rotating the photoconductive drum at 50 rpm under an irradiation time of 5 minutes, and further drying is performed at 130 ° C. for 30 minutes to provide a surface layer of 5 μm. An electrophotographic photoreceptor of the present invention was produced.

<Coating liquid for surface layer formation>
5 parts of trimethylolpropane triacrylate (trifunctional acrylic monomer) (trade name: SR351S, manufactured by Sartomer Co., Ltd.)
The following, a radically polymerizable compound having a charge transporting structure 5 parts The following photopolymerization initiator 0.3 part Tetrahydrofuran (boiling point 64 to 65 ° C.) 70 parts

2 except that an electrophotographic photosensitive drum is attached to the apparatus as shown in FIG. 2 and He gas (density 0.1786 kg / m ³ (0 ° C., 1 atm)) is injected into the vacuum chamber while reducing the pressure with a rotary pump. An electrophotographic photosensitive member was produced in the same manner as in Example 1.

[Comparative Example 1]
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the inside of the vacuum chamber was irradiated with light by an LED light source (manufactured by Eye Graphics) under normal pressure (101 × 10 ³ Pa) and an air environment.

[Comparative Example 2]
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that oxygen gas (density 1.429 kg / m ³ (0 ° C., 1 atm)) was injected into the vacuum chamber instead of the inert gas.

[Comparative Example 3]
An electrophotographic photoreceptor in the same manner as in Comparative Example 1 except that the irradiation time was changed to 3 minutes using an AC Fusion UV irradiation device (F600V-20QPN) and a D bulb instead of the LED light source in Comparative Example 1. Was made.

The test method performed in the present invention is shown below.
<Evaluation of surface condition>
The surface layer was evaluated by magnifying the surface layer before accelerated wear with an optical microscope.
<Image evaluation>
The photoconductor was mounted on RICOH Pro 900, 1000 halftone images were passed through in an environment of 30 ° C. and 90%, and after standing for 24 hours, one halftone image was output to evaluate the decrease in image density.
<Durability test>
The photoconductor was mounted on RICOH Pro 900, the dark portion potential was set to -900 V, and the light portion potential was measured. Thereafter, 50,000 sheets of A4 size and 50,000 sheets were further passed, and the bright part potential measurement was performed after each pass. The film thickness was measured after the initial 50,000 sheets and 100,000 sheets were passed, and the amount of wear due to the passing was measured. The film thickness of the photosensitive member was measured using an eddy current film thickness measuring device (manufactured by Fischer Instrument).
The measurement results are shown in Table 1.

(About Fig. 1 and Fig. 2)
1 Vacuum chamber 2 Conductive support (photosensitive drum)
3 LED-UV irradiation unit 4 Depressurization port 5 Inert gas injection port (FIGS. 3 and 4)
31 Conductive Support 33 Single Layer Photosensitive Layer 35 Charge Generation Layer 37 Charge Transport Layer 39 Crosslinked Surface Layer (Surface Layer)
(About Figure 5)
DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Static elimination lamp 3 Charging means (charger)
DESCRIPTION OF SYMBOLS 5 Image exposure part 6 Developing unit 7 Charger before transfer 8 Transfer body conveyance roller 9 Transfer body 10 Transfer charger 11 Separation charger 12 Separation claw 13 Charger before cleaning 14 Cleaning fur brush 15 Cleaning blade 16 Lubricant application roller 17 Lubricant 18 Lubricant application blade

JP 56-48637 A JP-A 64-1728 JP-A-4-281461 JP-A-8-262679 (Patent No. 3262488) JP-A-5-216249 (Patent No. 3194392) JP 2000-66425 A (Patent No. 4011791) JP 2004-302450 A (Patent No. 4145820) JP 2004-302451 A (Patent No. 4266859) JP 2004-302452 A JP 2009-139609 A JP 2008-134505 A

Claims (10)

  In the method for producing an electrophotographic photosensitive member having at least a photosensitive layer and a surface layer on a conductive support, after the step of forming a coating film as a surface layer using a coating solution containing a radical polymerizable compound The surface layer is formed by including a step of curing the coating film by irradiation of light energy using an LED as a light source, and the curing step of the coating film is a step of forming a coating film as the surface layer. The latter electrophotographic photosensitive member is moved into a sealed container in which an LED irradiation unit is installed, and after sealing the sealed container, when the light energy is irradiated, the gas in the sealed container is discharged while being inactive. A method for producing an electrophotographic photoreceptor, comprising injecting a gas.   2. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the inert gas is nitrogen, helium, neon, argon, xenon, or radon alone or in combination.   3. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the specific gravity of the inert gas is smaller than oxygen.   The radically polymerizable compound (b) having no charge transporting structure and / or a radically polymerizable compound (b) having a charge transporting structure (b), wherein the radically polymerizable compound has no charge transporting structure. The method for producing an electrophotographic photosensitive member according to any one of the above.   The method for producing an electrophotographic photosensitive member according to claim 4, wherein the radical polymerizable monomer (A) having no charge transporting structure is trifunctional or more.   6. The electrophotographic photosensitive member according to claim 4, wherein the functional group of the radical polymerizable monomer (A) having no charge transporting structure is an acryloyloxy group and / or a methacryloyloxy group. Method.   The method for producing an electrophotographic photosensitive member according to claim 4, wherein the radical polymerizable compound (B) having a charge transporting structure is monofunctional.   8. The electrophotographic photosensitive member according to claim 4, wherein the functional group of the radical polymerizable compound (b) having a charge transporting structure is an acryloyloxy group and / or a methacryloyloxy group. Manufacturing method.   An electrophotographic photosensitive member produced by the method according to claim 1.   An image forming apparatus comprising at least the electrophotographic photosensitive member according to claim 9 and a mechanism for applying a lubricant to a surface of the electrophotographic photosensitive member.

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