JP2009025382A - Electrophotographic photoreceptor and method of manufacturing the same, and image forming apparatus and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an electrophotographic photoreceptor having a single layer type photosensitive layer capable of attaining both mechanical durability and electrostatic durability and outputting an image of high image quality even after repeated use for a long term, to provide the eletrophotographic photoreceptor manufactured by the method, and to provide an image forming apparatus and a process cartridge using the photoreceptor. <P>SOLUTION: The electrophotographic photoreceptor is manufactured by providing, on a conductive support 1, a cured resin layer obtained by curing reaction of a compound having no charge transporting structure and a reactive compound having a charge transporting structure, bringing a supercritical fluid and/or a subcritical fluid containing a charge generating material and at least one of hole transport material and electron transport material into contact with the cured resin layer to form the single layer type photosensitive layer 2. The image forming apparatus and the process cartridge for image forming apparatus are constituted using the photoreceptor. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrophotographic technique applied to a copying machine, a laser printer, a facsimile, a direct digital plate making machine, and the like. Specifically, it has excellent electrostatic and mechanical durability, and stable high-quality images even in long-term repeated use. The present invention relates to a method for producing an electrophotographic photosensitive member having a single-layer type photosensitive layer that can be output, an electrophotographic photosensitive member produced thereby, an image forming apparatus using the same, and a process cartridge for the image forming apparatus.

Electrophotographic photoreceptors applied to an image forming apparatus using an electrophotographic system are roughly classified into inorganic photoreceptors and organic photoreceptors. Organic photoreceptors are subject to wear and durability due to repeated use compared to inorganic photoreceptors, but there are merits in productivity, manufacturing cost, freedom of material selection, burden on the global environment, etc. At present, organic photoreceptors are widely used.
These organophotoreceptors can be classified by layer structure, for example, [1] Photoconductive resins represented by polyvinylcarbazole (PVK) and PVK-TNF (2,4,7-trinitrofluorenone). A homogeneous single layer type in which a representative charge transfer complex is provided on a conductive support, [2] a dispersed single layer type in which a pigment such as phthalocyanine or perylene is dispersed in a resin, provided on the conductive support, [3] A layered type in which a charge generation layer (CGL) containing a charge generation material and a charge transport layer (CTL) containing a charge transport material are laminated on a conductive support and separated into functions can be roughly classified. Among these, the laminated type is the mainstream because it is advantageous for wear resistance and high sensitivity.

  In recent years, with the digitization of image forming apparatuses, speeding up, downsizing, and full color have been rapidly progressed, and accordingly, further enhancement of durability of the photosensitive member has been demanded. In addition to increasing the speed of image output, it is necessary to reduce the diameter of the photoconductor in order to reduce the size of the apparatus. Therefore, it is necessary to improve the wear resistance of the photoconductor. In order to output a full color image, it is necessary to superimpose at least four colors of cyan, magenta, yellow, and black, which is also a factor that promotes wear of the photoreceptor. Recently, a tandem-type full-color image forming apparatus including four photoconductors corresponding to four color developing units has been rapidly spread. However, in order to enclose the four photoconductors, the small diameter of the photoconductor is required. In order to develop image forming apparatuses in the future, high durability of the photoreceptor is a major issue.

  The single layer type photoconductor has a charge generation function on the surface layer of the photoconductor, so the influence of abrasion is very large. The laminated type in which the charge transport layer is formed on the surface of the photoconductor is more durable. It is advantageous. However, if wear of the charge transport layer progresses, it will lead to decrease in charge retention, sensitivity deterioration, increase in dirt due to increase in electric field strength, etc. Become. On the other hand, if the thickness of the charge transport layer is greatly increased, a margin for wear is obtained, but the distance until the charge injected into the charge transport layer reaches the surface increases, and the lateral direction of the charge As a result, the influence of diffusion on the screen increases, causing a reduction in image quality. For this reason, many methods have been proposed and put into practical use in which a method for increasing the wear resistance of the charge transport layer and a structure in which a protective layer is further provided on the charge transport layer are proposed.

  Techniques for improving the abrasion resistance of the photoreceptor include [a] a method using a curable binder resin for the surface layer (protective layer) (see, for example, Patent Document 1), and [b] a method using a polymer charge transport material. (For example, refer to Patent Document 2), [c] A method of dispersing filler or the like in the surface layer (protective layer) (for example, refer to Patent Document 3) has been proposed. Although the wear resistance of the photoconductor has been improved by these techniques, the life of the photoconductor is not always satisfied. The reason is considered as follows.

  In the method using the curable binder resin [a], the surface layer needs to have a charge transport function in order to achieve both wear resistance and electrostatic characteristics. However, even if a film is formed by simply mixing the polymerizable monomer and the charge transport material, the charge transport material inhibits the curing of the polymerizable monomer and the curing reaction does not proceed sufficiently, so that the wear resistance is not satisfied. If the curing reaction does not proceed sufficiently, unreacted monomers remain in the photosensitive layer, and these functional groups serve as charge trap sites, causing a significant increase in residual potential and a decrease in sensitivity. Further, when the curing is not sufficient, fine cracks and irregularities are formed on the surface, which greatly affects the cleaning properties of the toner remaining on the photoreceptor, resulting in poor cleaning and image quality degradation. In order to avoid this, it is necessary to carry out a curing reaction with a charge transporting compound having a polymerizable functional group, whereby wear resistance and electrostatic characteristics are improved. However, if a surface layer is provided mainly with a curable resin on a charge transport layer mainly containing a thermoplastic resin, the surface layer may crack or the surface layer may peel off. Furthermore, charge is trapped at the interface between the charge transport layer and the surface layer, and lowering the electrostatic characteristics is also a big problem.

  In addition, the method using the polymer charge transport material [b] is effective in improving the wear resistance as compared with a binder resin containing a low molecular charge transport material, and is compatible with electrostatic properties. Is possible. However, the wear resistance is clearly inferior to the case where a curable binder resin is used, and it is difficult to achieve the required durability only by this method. Production cost is also an issue.

  Moreover, the method of dispersing the filler in the surface layer of [c] has an advantage that the filler is not limited by the binder resin or the charge transporting substance because the filler exhibits an effect on the wear resistance. However, although it is an effective method for improving the wear resistance, it is less effective than the case of using a curable binder resin. In some cases, resolution is lowered by inducing diffusion of charges moving to the surface. In the case of a high resistance filler, it becomes a charge trap site, causing a significant increase in residual potential, and in the case of a low resistance filler, it promotes charge diffusion and causes image flow. Very difficult in terms of stability. Further, the inclusion of the filler increases the surface irregularities, thereby causing problems such as increasing the influence of cleaning failure by accelerating the deterioration of the cleaning blade.

  As described above, although many methods for improving the wear resistance of the photoreceptor have been proposed, the electrostatic characteristics and image quality of the photoreceptor have not been realized, and the life of the photoreceptor has not been satisfied. . In addition, as the photoconductors are laminated, the multilayer structure in which even the protective layer is laminated not only hinders productivity and cost reduction but also forms many layer interfaces up to the surface of the photoconductor. Become. This leads to an increase in charge trapping at the layer interface, and causes, for example, a decrease in image density due to an increase in residual potential, or a ghost in which an image output previously on a halftone image is projected as an afterimage. As described above, the functions have been separated and multilayered to improve the wear resistance of the photoreceptor, and as a result of repeated improvements, the wear resistance has been improved. The actual situation is that the durability of the photosensitive member has not been improved as expected due to the deterioration of the toner.

  In the photoconductor, the charge generated by the charge generating material is moved to the surface of the photoconductor by the charge transport material to form an electrostatic latent image. Therefore, a shorter charge transfer distance is advantageous for higher image quality. In that respect, the single layer type photoreceptor is more effective than the laminated type. In addition, a single-layer type photoreceptor has a great advantage in terms of productivity and cost because it is not necessary to superimpose many layers. At the same time, it contributes to the reduction of the amount of solvent and energy used in the production of the photoconductor, and also has a great merit from the viewpoint of protecting the global environment, such as simplification of the photoconductor recycling work.

  As described above, although the single-layer type photoreceptor has a great advantage, it is considered that the biggest problem is durability. Since the single-layer type photosensitive layer has a charge generation function, a hole transport function, and an electron transport function in one layer, if the film thickness decreases due to wear, the influence on the electrostatic characteristics and image quality is very large. From such a viewpoint, it is considered effective to form a single photosensitive layer on a conductive support and cure the photosensitive layer. This makes it possible to enhance the durability while taking advantage of the merit of the single-layer type photoreceptor, and is considered to be a very effective method. The following are disclosed as related art.

For example, there has been proposed a photoreceptor in which a binder resin is a visible light curable resin in a single-layer or laminated photosensitive layer composed of a charge generation material, a charge transport material, and a binder resin (see, for example, Patent Document 4). According to this, thermosetting resin requires a lot of heat and time for curing, and the life of the coating solution is relatively short, making stable production difficult, and UV curable resin absorbs ultraviolet rays by the charge transport material in the photosensitive layer. Therefore, it is described that it is difficult to produce a photosensitive member with high sensitivity. In particular, the visible light curable resin that the charge transporting material does not absorb is used because the charge transporting material absorbs ultraviolet rays and the structure changes to become a trap or affect the charge generating material. Is.
According to this method, it is possible to expect the effect of eliminating the problems associated with the deterioration due to the ultraviolet absorption of the charge transport material. However, visible light has lower energy than ultraviolet light, and the curing reaction may not proceed sufficiently. In addition, since the charge transport material does not have a functional group that cures with the photopolymerizable monomer in particular, the possibility that the charge transport material may cause curing inhibition cannot be denied, and is a method that can realize sufficient durability. I can't judge.

  In addition, as a single-layer or multi-layer photoreceptor, a photoreceptor in which the outermost resin component includes an electron beam curable resin has been proposed (see, for example, Patent Document 5). The advantage of electron beam curable resins is that, unlike photopolymerizable resins, no additives such as polymerization initiators are required, so that sensitivity deterioration due to charge traps and bright part potential increase are unlikely to occur. ing. However, even if a curing means using an electron beam is used, the charge transport material contained does not have a functional group that undergoes a curing reaction, and it is considered that the problem of curing inhibition due to the inclusion of the charge transport material cannot be avoided.

  As described above, the method of increasing the wear resistance by using the curable binder resin for the photosensitive layer of the single-layer type photoreceptor has great merit, but has not been realized yet. That is, the single-layer type photosensitive layer is responsible for charge generation function, hole transport function and electron transport function in one layer, for example, inhibition of curing due to charge generation material or charge transport material contained in the photosensitive layer occurs, It is considered that the unreacted functional group of the monomer remaining due to the inhibition of the curing, additives such as a polymerization initiator, and the like affect the wear resistance, and the electrostatic characteristics are deteriorated.

  When a reactive monomer having no charge transporting structure and a reactive compound having a charge transporting structure are subjected to a curing reaction in a single-layer type photosensitive layer, the effects of the above-described curing inhibition and unreacted functional groups can be reduced. However, the influence of ultraviolet irradiation used during the curing reaction on the charge generation material and charge transport material cannot be ignored. In particular, the deterioration of the charge generating material has a fatal effect on the electrostatic characteristics.

Although it is possible to increase the wear resistance by a structure in which a protective layer is laminated on a single-layer type photosensitive layer, the merit of the single-layer type structure is impaired by the lamination of the protective layer, and the photosensitive layer and the protective layer are protected. By forming an interface between the layers, problems of cracking and peeling of the protective layer are likely to occur. In addition, charge trapping at the interface causes deterioration of electrostatic characteristics and image quality, and high durability cannot be said to be sufficient.
In spite of the demand for higher durability of photoconductors, single layer type photoconductors have many merits, but the conventional technology is not durable enough. Is proceeding in the direction. However, there are many problems due to the multi-layering, and even though the wear resistance can be improved, the actual situation is that the electrostatic characteristics and the image quality stability are not satisfied.
In other words, if wear resistance can be improved in a single-layer type photoreceptor, both high image quality and high durability can be achieved, and benefits for productivity and the global environment can be obtained. It had been.

JP 56-48637 A JP-A 64-1728 JP-A-4-281461 Japanese Patent Laid-Open No. 1-116553 JP-A-3-246551

  The present invention has been made in view of the problems of the above-described conventional techniques, and its purpose is basically a photoreceptor having a single-layer type photosensitive layer that is extremely excellent in terms of productivity, cost reduction, and high resolution. A method for producing an electrophotographic photoreceptor capable of outputting a high-definition image even in repeated use over a long period of time, realizing both mechanical durability and electrostatic durability that could not be realized by conventional methods. And an electrophotographic photosensitive member manufactured thereby, and an image forming apparatus and a process cartridge using the same.

  The present inventors have been able to stably output a high-definition image faithful to a manuscript for a long period of time, improve productivity and production cost, and are not sensitive to the conventional common sense considering the global environment. As a result of intensive studies on the production method of the body, a reactive compound having no charge transporting structure (hereinafter referred to as “reactive monomer” or “reactive monomer or oligomer”) is formed on the conductive support. And a resin film mainly composed of a reactive compound having a charge transporting structure is formed and cured in advance to form a cured resin layer. A supercritical fluid and / or a subcritical fluid is added to the cured resin layer. Through the formation of a photosensitive layer formed by injecting and forming a charge generation material and at least one of a hole transport material and an electron transport material, the inventors have found that these can be achieved. That is, the inventors have found that the above problems can be solved by the inventions described in the following [1] to [14], and have reached the present invention. Hereinafter, the present invention will be specifically described.

[1]: The above-described problem is a method for producing an electrophotographic photosensitive member comprising a single-layer photosensitive layer having at least a charge generation function, a hole transport function, and / or an electron transport function on a conductive support. And
The photosensitive layer has a cured resin layer formed by a curing reaction of a reactive compound having no charge transporting structure and a reactive compound having a charge transporting structure. It is solved by a method for producing an electrophotographic photoreceptor, which is formed by contacting a supercritical fluid and / or a subcritical fluid containing at least one substance.

  A charge generation material, a hole transport material, and an electron transport are formed on a cured layer obtained by curing a reactive compound (for example, a reactive monomer or oligomer) having no charge transport structure and a reactive compound having a charge transport structure. By the manufacturing method in which at least one kind of substance is injected, both mechanical durability and electrostatic durability can be achieved, and a high-definition and high-quality image can be output even during long-term repeated use.

  [2]: In the method for producing an electrophotographic photosensitive member according to [1], the cured resin layer is formed by being cured by irradiating at least one of light, heat, and radiation.

  Depending on the reactive compound having no charge transporting structure and the reactive compound having a charge transporting structure, a suitable one of the above curing means is selected and cured to ensure a three-dimensional network structure. And excellent mechanical durability is ensured.

  [3]: In the method for producing an electrophotographic photosensitive member according to [1] or [2], the cured resin layer is made of at least one of a urethane resin, a phenol resin, an acrylic resin, a siloxane resin, and an epoxy resin. It is characterized by.

  By using the above resin, it is possible to realize the abrasion resistance required as a single-layer type photosensitive layer, and to charge generation material, hole transport material and / or via the supercritical fluid and / or subcritical fluid to the cured layer. Since the injection property of the electron transport material is also good, a photosensitive layer having excellent electrostatic and mechanical durability can be obtained.

  [4]: The method for producing an electrophotographic photosensitive member according to any one of [1] to [3], wherein the resin forming the cured resin layer includes a triarylamine structure. .

  Since the cured resin layer contains a triphenylamine structure, it has not only excellent charge transport properties but also injection properties of charge generating materials, hole transport materials, and electron transport materials via supercritical fluids and / or subcritical fluids. Therefore, the photosensitive layer can be excellent in electrostatic and mechanical durability.

  [5]: The method for producing an electrophotographic photosensitive member according to any one of [1] to [4], wherein the charge generation material is an azo pigment-based compound.

  Even when it is contained in a supercritical fluid and / or a subcritical fluid, it can be used stably, so that it can be used more preferably and the sensitivity is excellent.

  [6]: The method for producing an electrophotographic photosensitive member according to any one of [1] to [5], wherein the hole transport material is a triarylamine derivative.

  Triphenylamine derivatives are not only excellent in hole transport properties, but also effective in stabilizing electrostatic properties, and injecting into hardened layers via supercritical fluids and / or subcritical fluids. Since it is excellent, it is used particularly effectively.

  [7]: The method for producing an electrophotographic photosensitive member according to any one of [1] to [6], wherein the electron transport material is a naphthalene tetracarboxylic acid diimide derivative.

  The naphthalenetetracarboxylic acid diimide derivative is not only excellent in electron transport properties, but also excellent in injectability into a cured resin layer via a supercritical fluid and / or a subcritical fluid, and thus is particularly effective. It is done.

  [8]: In the method for producing an electrophotographic photosensitive member according to any one of [1] to [7], an antioxidant, a light stabilizer, a dispersion aid are further added to the supercritical fluid and / or subcritical fluid. It contains at least one of an agent, a lubricant and a filler.

  According to the above additives, for example, suppression of charge decrease caused by ozone gas or NOx gas, improvement of film quality, improvement of slipperiness of the surface of the photosensitive layer, prevention of deterioration due to light irradiated to the photosensitive layer, improvement of wear resistance, cleaning property Therefore, it is possible to avoid the inhibition of curing due to the addition of these substances, so that further functions can be imparted without affecting the mechanical durability and the electrostatic durability.

  [9]: In the method for producing an electrophotographic photosensitive member according to any one of [1] to [8], the supercritical fluid and / or subcritical fluid contains at least carbon dioxide.

  Carbon dioxide has a critical temperature close to room temperature, and is particularly preferable in terms of excellent handleability. Furthermore, since it is suitable for dissolving the organic material constituting the photoconductor and can be processed without being decomposed, it is most suitable for the substance injection process to the cured resin film of the present invention.

  [10]: In the method for producing an electrophotographic photosensitive member according to any one of [1] to [9], an undercoat layer is provided between the conductive support and the photosensitive layer. And

  The undercoat layer prevents charge injection from the conductive support to the photosensitive layer, prevents charge reduction, background contamination and moire, and can stably output a high-quality image.

  [11]: The above-described problem is solved by an electrophotographic photosensitive member produced by the method according to any one of [1] to [10].

  [12]: The above-mentioned problems include at least charging means for charging the surface of the electrophotographic photosensitive member, electrostatic latent image forming means for forming an electrostatic latent image on the electrophotographic photosensitive member, and toner on the electrostatic latent image. An image forming apparatus comprising: a developing unit that forms a visible image by adhering to the recording medium; and a transfer unit that transfers the visible image to a recording medium. The electrophotographic photosensitive member according to [11] This is solved by an image forming apparatus that is a photosensitive member.

[13]: The above-described problem includes at least a charging unit, an electrostatic latent image forming unit, a developing unit, and a transfer unit, and the developing unit has a plurality of developing units filled with toners of different colors. A tandem image forming apparatus including a plurality of electrophotographic photosensitive members corresponding to a developing unit,
This is solved by an image forming apparatus characterized in that the electrophotographic photosensitive member is the electrophotographic photosensitive member described in [11].

  [14]: The above-mentioned problems include a charging means for charging the surface of the electrophotographic photosensitive member, an electrostatic latent image forming means for forming an electrostatic latent image on the electrophotographic photosensitive member, and a toner attached to the electrostatic latent image. At least one means selected from developing means for forming a visible image, transfer means for transferring the visible image to a recording medium, and cleaning means for removing toner remaining on the surface of the electrophotographic photosensitive member after the transfer; The process cartridge for an image forming apparatus is characterized by being integrated with the electrophotographic photosensitive member according to 11) and being detachable from the main body of the image forming apparatus.

According to the production method of the present invention, an electrophotographic photosensitive member having a single-layer type photosensitive layer that has both mechanical durability and electrostatic durability, and can output a high-resolution and high-definition image even when used for a long period of time. Is provided.
That is, at least one of a charge generation material, a hole transport material, and an electron transport material is applied to a cured resin layer obtained by curing a reactive monomer having no charge transport structure and a reactive compound having a charge transport structure. By contacting the contained supercritical fluid and / or subcritical fluid, at least one of these charge generation materials, hole transport materials, and electron transport materials is injected, so it has excellent wear resistance and stable electrostatic properties. A photosensitive layer is formed. As a result, even when used repeatedly for a long time, image quality deterioration due to wear is small, and high-quality images can be output stably.
In addition, since it is not exposed to high energy (for example, high energy light such as ultraviolet rays) necessary for the curing reaction in a state where the charge generating material is contained, it does not change in quality, and the residual potential is increased and sensitivity is decreased. Is prevented. In addition, since the solvent remaining in the photosensitive layer is removed by being contacted with the supercritical fluid and / or the subcritical fluid, an effect of reducing characteristic deterioration and fluctuation due to the residual solvent can be obtained.
In addition, since the charge generation material is contained in the outermost surface layer, there is little influence of lateral diffusion during movement of the charge generated by the charge generation material, and an image faithful to the original can be formed and used repeatedly. Even if it can output stably. Furthermore, by making it a single-layer type photosensitive layer, productivity improvement and cost reduction are achieved, and in addition, the production method is improved by using a supercritical fluid and / or a subcritical fluid, We have made it possible to reduce the burden on the global environment by reducing waste materials and conserving resources.
According to the electrophotographic photosensitive member of the present invention, both mechanical durability and electrostatic durability, which have been difficult in the past, are realized by a single layer type photosensitive member, thereby achieving high durability, downsizing, and high speed. Therefore, even when used repeatedly for a long time, there is little deterioration in image quality due to wear, and high-definition, high-quality images can be output stably.
According to the image forming apparatus of the present invention, even if image formation is repeatedly performed, the occurrence of abnormal images is small, and a high-quality image can be stably output at any time. In particular, according to the tandem image forming apparatus of the present invention, a full-color and high-definition image can be output, and the change in the film thickness and electrostatic characteristics of the photosensitive layer with time is small. Excellent.
According to the process cartridge of the present invention, highly stable image output is possible, the handling is good, the maintainability is improved, and the cost is reduced.

As described above, the present invention is a method for producing an electrophotographic photoreceptor, comprising a single-layer photosensitive layer having at least a charge generation function, a hole transport function and / or an electron transport function on a conductive support. And
The photosensitive layer has a cured resin layer formed by a curing reaction of a reactive compound having no charge transporting structure and a reactive compound having a charge transporting structure. It is formed by contacting a supercritical fluid and / or a subcritical fluid containing at least one substance.

  By using a photoconductor provided with the single-layer type photoconductive layer, the merit of high-definition image formation, improvement in photoconductor productivity, and reduction in the use of solvents can be achieved. Regarding abrasion resistance, which is the biggest problem of single-layer type photosensitive layers, as described above, reactive compounds (reactive monomers or oligomers) having no charge transport structure and reactive compounds having a charge transport structure A cured resin layer (hereinafter sometimes referred to as a “cured layer”) subjected to a curing reaction of at least one of a charge generation material, a hole transport material, and an electron transport material via a supercritical fluid and / or a subcritical fluid. It is possible to solve by injecting.

Specifically, a resin layer mainly composed of a reactive compound (reactive monomer or oligomer) having no charge transporting structure and a reactive compound having a charge transporting structure is formed on a conductive support. 3) High density in a three-dimensional manner by sufficiently curing it to form a hardened layer, and then contacting the hardened layer with a supercritical fluid and / or subcritical fluid containing a charge generating material, a charge transporting material, etc. In this method, a charge generation material or a charge transport material is injected into the cured layer cured in step 1 to form a photosensitive layer. This makes it possible to “include a charge generating substance and a charge transport substance in a cured resin layer formed by precuring”, which is impossible with the conventional method.
In addition, even though the photosensitive member has a single-layer type photosensitive layer, a high-definition and high-quality image can be stably output even when used repeatedly, and a highly durable photosensitive member has been realized. In addition to achieving both mechanical durability and electrostatic durability, it is possible to manufacture photoconductors that have improved photoconductor productivity, reduced production costs, and reduced the burden on the global environment. It was. This will be described in detail below.

  The effect of the photoconductor produced by the method for producing an electrophotographic photoconductor in the present invention is as follows. First, it has high wear resistance, there is little deterioration in image quality due to wear even when used repeatedly for a long time, and high-quality images are stabilized. It can be output. As described above, the photoreceptor of the present invention contains a reactive compound (reactive monomer or oligomer) having no charge transporting structure and a reactive compound having a charge transporting structure in advance for a curing reaction. Curing inhibition by the charge transport material can be avoided. Therefore, a photosensitive layer having little unreacted monomer and excellent wear resistance can be obtained. Further, since the curing reaction proceeds uniformly, there is little uneven wear that partially wears. Furthermore, it is excellent in scratch resistance and can prevent image defects caused by scratches on the surface formed by repeated use.

Second, it is possible to suppress side effects on electrostatic characteristics such as increase in residual potential and decrease in sensitivity. Usually, irradiation with high energy light such as heat and ultraviolet rays accelerates the curing reaction and can form a three-dimensional network structure, which is an effective means for improving wear resistance. However, when the high energy light is irradiated, the charge generation material contained in the photosensitive layer is deteriorated or deteriorated, resulting in an increase in residual potential or sensitivity deterioration. However, in the method for producing a photoconductor of the present invention, the charge generation material is not contained in the layer during the curing reaction of the resin layer, and is injected into the cured resin layer after the curing reaction. There is no light irradiation. As a result, it is possible to prevent deterioration and alteration of the charge generation material and to stably maintain excellent electrostatic characteristics.
In the present invention, since the photosensitive layer itself is cured, it is not necessary to form a protective layer on the surface. For this reason, as in the case of a photoreceptor having a photosensitive layer and a protective layer, charges are not trapped at the interface between the photosensitive layer and the protective layer, so that electrostatic characteristics can be highly stabilized and abnormal images can be prevented from occurring. Are better. Further, although the solvent remaining in the photosensitive layer affects the electrostatic characteristics, in the present invention, the residual solvent can be removed by contacting with the supercritical fluid and / or the subcritical fluid. One of the effects on the stabilization of.

  Third, it is possible to form an image faithful to the original and to achieve both high durability. In the photoreceptor of the present invention, since the charge generating material is contained in the outermost surface layer, the distance that the charge generated by the charge generating material moves to the surface of the photoreceptor is short. This reduces the amount of charge diffusion during charge transfer, prevents character thickening and toner scattering, and is very effective in improving resolution. Furthermore, since it is excellent in abrasion resistance, the high-quality image can be output stably even when used repeatedly. Moreover, since there is little influence of hardening inhibition, the stable cured film with few generation | occurrence | production of a crack and surface unevenness | corrugation can be formed. This not only has an effect on wear resistance and electrostatic characteristics, but also has an effect of improving the cleaning property of toner or deposits remaining on the photoreceptor, and can prevent the occurrence of abnormal images due to poor cleaning.

  Fourth, the method for producing a photoreceptor is excellent in productivity and cost reduction. By realizing the charge generation function, hole transport function, electron transport function and protective function in one layer of photosensitive layer, the production speed and production speed are improved compared to the multilayer type photoreceptor that requires multiple layers of coating and each time high temperature drying is required. Production costs are greatly improved. In addition, cost reduction is expected due to the high durability of the photoreceptor itself. Furthermore, if a hardened layer is provided on the conductive support and the substance contained in the hardened layer is contained in the supercritical fluid and / or subcritical fluid, they can be injected into the layer at one time. This is a method with excellent production efficiency.

  Fifth, there is an effect for reducing the load on the global environment. Since the photosensitive layer is a single layer, the amount of solvent used can be greatly reduced. In the injection process of charge generation materials and charge transport materials, the supercritical fluid and subcritical fluid are gases if they are returned to room temperature and normal pressure. It is not necessary, and since there is almost no residual solvent, there is no need for a high-temperature drying treatment for evaporating the solvent. In addition, since it is a single layer, there is little load for recycling the photoreceptor and reusing resources. Furthermore, it can be said that the photoconductor manufacturing method achieves resource saving by realizing high durability of the photoconductor and greatly contributes to reducing the load on the global environment.

Next, the best mode for carrying out the present invention will be described.
First, the supercritical fluid or subcritical fluid will be described.
The supercritical fluid exists as a non-condensable high-density fluid in a temperature / pressure region that exceeds the limit (critical point) where gas and liquid can coexist, does not cause condensation even when compressed, and exceeds the critical temperature. And as long as it is the fluid in the state more than a critical pressure, there is no restriction | limiting in particular, According to the objective, it can select suitably. Supercritical fluids are characterized by both gas and liquid properties, that is, gas properties in which molecules have large kinetic energy when they are at high temperatures, and liquids in which molecules gather and stabilize when they are under high pressure. It also has a special nature. Therefore, it has the characteristics that it is excellent in diffusibility and permeability and has a very high ability to dissolve substances. The solubility can be controlled by adjusting the temperature and pressure.

On the other hand, the subcritical fluid in the present invention means that it is in a high-density liquid state under temperature and pressure conditions in the vicinity of a critical point that does not reach a supercritical fluid. The state where either one of the temperature and the pressure exceeds the critical point is also included. In the present invention, even if it is not necessarily in a supercritical state, it is sufficient if an effect of injecting a charge generating substance or a charge transporting substance into the cured resin layer is obtained, and even a subcritical fluid can be used effectively. As described above, the supercritical fluid has both characteristics of gas and liquid, and it is considered that a state close to a high-density liquid is particularly effective in the contact treatment with the cured resin layer. Therefore, although the fluid to be treated is a gas at normal temperature and normal pressure, it can be said that the effect can be obtained even when the fluid is in a liquid state and not in a supercritical state.
For example, the critical pressure of carbon dioxide is 7.53 MPa, and if the pressure is higher than that, it has been confirmed by experiments that a rapid increase in density is exhibited even if the critical temperature is less than 31 ° C. From this result, if the pressure is 7.53 MPa or more and the density is at least 0.7 (g / cm ³ ) or more, it can be determined that the subcritical state is reached even if the critical temperature is not reached. However, this is limited to the case of gas at normal temperature and normal pressure such as carbon dioxide.

  Examples of the supercritical fluid and / or subcritical fluid include carbon monoxide, carbon dioxide, ammonia, nitrogen, water, methanol, ethanol, ethane, propane, butane, hexane, 2,3-dimethylbutane, benzene, and chloro. Trifluoromethane, dimethyl ether and the like can be mentioned. In the present invention, those having a lower critical temperature are preferable, and carbon dioxide is particularly preferably used.

  In the present invention, a supercritical fluid having a critical temperature of 30 to 40 ° C. and near room temperature is preferable, and carbon dioxide having a critical temperature of 31 ° C. and a critical pressure of 7.53 MPa is most preferable. The temperature and pressure can be freely set depending on the material used, but the temperature is 20 to 150 ° C., preferably 30 to 100 ° C., and the pressure is 5 to 100 MPa, preferably 7 to 70 MPa. is there. If the temperature or pressure is too low, carbon dioxide is unlikely to become a supercritical fluid or subcritical fluid, and the effects of the present invention are difficult to obtain. On the other hand, if the temperature or pressure is too high, the cured resin layer may be dissolved or decomposed. However, since the use of the supercritical fluid or subcritical fluid in the present invention is intended to inject the charge generation material or the charge transport material into the cured layer, the condition for the cured layer to dissolve is not preferable. In this invention, since it hardens | cures previously, application conditions are comparatively wide. It is only necessary to set the temperature and pressure conditions while confirming the physical properties of the materials to be used and the effects thereof, and the fact that the conditions can be arbitrarily set is a point that is very excellent in practicality of the present invention.

  Further, as described above, it can also be suitably used as a subcritical fluid having a temperature slightly lower than the temperature in the supercritical state or a pressure slightly lower than the pressure in the supercritical state. That is, the effect can be obtained even when a subcritical fluid such as subcritical carbon dioxide is brought into contact with the cured resin layer. Various materials mentioned as the supercritical fluid can be preferably used as the subcritical fluid.

The supercritical fluid and the subcritical fluid may be used singly or as a single substance, or two or more kinds may be used in combination as a mixture. When other fluids are used in addition to the supercritical fluid and the subcritical fluid, specifically, the above supercritical fluid or subcritical fluid such as carbon monoxide, nitrogen, ethane, propane, or ethylene is used in combination. can do.
Moreover, an organic solvent can be mixed with the supercritical fluid and the subcritical fluid as an entrainer. As a result, the solubility of the substance to be injected can be controlled, and the application range of the substance can be expanded. As the entrainer, it is preferable to select a solvent having a high affinity for the solute to be dissolved in the supercritical fluid and / or the subcritical fluid. As an example, alcohol solvents such as methanol and ethanol, hydrocarbon solvents such as hexane, cyclohexane and toluene, and ketone solvents such as acetone and methyl ethyl ketone are used, but there is no particular limitation.

  A device for injecting a charge generating material or a charge transport material into a hardened layer using a supercritical fluid or a subcritical fluid may be any device as long as the photoconductor can contact the supercritical fluid and / or subcritical fluid. It may be. Specifically, a conductive support having a pre-cured hardened layer formed in a high-pressure cell and a substance such as a charge generating substance or a charge transporting substance to be injected into the hardened layer are put, for example, carbon dioxide etc. While introducing, increase the temperature and pressure. As a result, the charge generation material and the charge transport material are dissolved in the supercritical fluid and / or subcritical fluid, and the charge generation material and the charge transport material are injected into the hardened layer formed on the conductive support. .

The state in which the supercritical fluid and / or subcritical fluid containing the charge generation material and / or the charge transport material are in contact with the precured hardened layer in the present invention is only required to be in physical contact with each other. If a supercritical fluid and / or a subcritical fluid is created in a high-pressure cell containing a charge generation material or a charge transport material, both naturally contact each other. Since the supercritical fluid and / or subcritical fluid has high solubility as described above and is excellent in diffusibility into the hardened layer, the charge generating material dissolved in the supercritical fluid and / or subcritical fluid The charge transport material is diffused and injected into the cured layer.
There are methods such as batch method using supercritical fluid and / or subcritical fluid in closed system, distribution method using circulating supercritical fluid or subcritical fluid, and combined method combining batch method and distribution method. Any of them can be used.

  In addition to injecting a charge generating substance or charge transporting substance using a supercritical fluid or a subcritical fluid, a substance to be contained in the photosensitive layer, for example, an antioxidant, a light stabilizer, a dispersion aid, a lubricant, etc. It is possible and effective to include these substances in the photosensitive layer by putting them together in a high pressure cell.

Hereinafter, the photosensitive member will be described including a manufacturing method based on the drawings.
FIG. 1 is a schematic cross-sectional view showing an example of an electrophotographic photoreceptor in the present invention, which is a photoreceptor having a photosensitive layer (2) formed on a conductive support (1).
FIG. 2 is a schematic cross-sectional view showing another example of an electrophotographic photosensitive member in which an undercoat layer [or intermediate layer] (3) is formed between the conductive support and the photosensitive layer of FIG.
The photosensitive layer (2) shown in FIGS. 1 and 2 comprises a reactive compound (reactive monomer or oligomer) having no charge transporting structure and a reactive compound having a charge transporting structure on a conductive support. It is formed by bringing a supercritical fluid and / or a subcritical fluid containing at least one of a charge generation material, a hole transport material and an electron transport material into contact with the cured layer subjected to the curing reaction.
The constituent layers of the electrophotographic photoreceptor will be described below.

<About conductive support>
Examples of the conductive support include those having a volume resistance of 10 ¹⁰ Ω · cm or less, such as metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, and platinum, tin oxide, and indium oxide. Metal oxide coated with film or cylindrical plastic or paper by vapor deposition or sputtering; aluminum, aluminum alloy, nickel, stainless steel, etc., and after they have been made into bare tubes by methods such as extrusion and drawing Pipes subjected to surface treatment such as cutting, super-finishing and polishing can be used. Endless nickel belts and endless stainless steel belts can also be used as the conductive support.

In addition to this, a conductive support prepared by dispersing conductive powder in a binder resin and coating a conductive layer on the conductive support can be used as the conductive support.
Examples of the conductive powder include carbon black, acetylene black; metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, silver, and metal oxide powder such as conductive tin oxide and ITO. 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, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly (N-vinylcarbazole), acrylic resin, silicone resin, epoxy resin, melamine Examples thereof include thermoplastic resins such as resins, urethane resins, phenol resins, and alkyd resins, thermosetting resins, and photocurable resins. The conductive layer can be provided by dispersing conductive powder and a binder resin in a solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, or toluene and applying the conductive powder and the binder resin.

Furthermore, using a heat-shrinkable tube containing conductive powder in materials such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, polytetrafluoroethylene fluororesin, etc. Those provided with a conductive layer can also be used as a conductive support.
In the present invention, among these, a cylindrical conductive support made of aluminum is most preferably used. Aluminum includes both pure aluminum and aluminum alloys. Specifically, JIS 1000, 3000, and 6000 series aluminum or aluminum alloys are suitable.

  In addition, an aluminum tube that has been subjected to an anodized film treatment can be used, which is particularly effective. Anodized films are anodized various metals and alloys in an electrolyte solution. Among them, a film called anodized aluminum or aluminum alloy that has been anodized in an electrolyte solution is very suitable. Yes. This has the effect of preventing image defects (background stains) that occur during reversal development without significantly affecting the increase in residual potential.

The anodizing treatment is performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid. Of these, treatment with a sulfuric acid bath is most suitable. By way of example, sulfuric acid concentration: 10-20%, bath temperature: 5 to 25 ° C., a current density: 1~4A / dm ^2, an electric field voltage: 5 to 30 V, the processing time: the processing in the range of about 5 to 60 minutes However, the present invention is not limited to this.
Since the anodic oxide film produced in this way is porous and has high insulating properties, the surface is in a very unstable state. For this reason, a change with time such as a change in the physical property value of the anodized film after the production can occur. In order to avoid this, it is preferable to further seal the anodized film. Examples of the sealing treatment include a method of immersing the anodized film in an aqueous solution containing nickel fluoride and nickel acetate, a method of immersing the anodized film in boiling water, and a method of treating with pressurized steam. Among these, the method of immersing in the aqueous solution containing nickel acetate is the most preferable.
Subsequent to the sealing treatment, the anodic oxide film is washed. The main purpose of this is to remove excess metal salts and the like attached by the sealing treatment. If this remains excessively on the surface of the support (anodized film), not only will it adversely affect the quality of the coating film formed on it, but generally low resistance components will remain, resulting in the occurrence of soiling. Will be promoted. The cleaning may be performed once with pure water, but it is preferable to perform multi-step cleaning. At this time, the final cleaning liquid is preferably deionized as much as possible. Further, it is preferable to perform physical contact cleaning with a contact member in one of the multi-step cleaning processes.
The thickness of the anodized film formed as described above is suitably about 5 to 15 μm. If it is too thin, the effect of the barrier property as an anodic oxide film is not sufficient, and if it is thicker than this, the time constant as the electrode becomes too large, and the residual potential may increase or the photoresponsiveness may decrease. There is.

<About photosensitive layer>
As described above, the photosensitive layer of the present invention is a single-layer type photosensitive layer. A cured layer obtained by curing a reactive compound (reactive monomer or oligomer) having no charge transporting structure and a reactive compound having a charge transporting structure contains a charge generating material, a hole transporting material, and an electron transporting material. It is formed by a manufacturing method in which at least one kind is injected through a supercritical fluid and / or a subcritical fluid. Thereafter, the reactive compound having no charge transporting structure and the reactive compound having the charge transporting structure have a functional group for causing a curing reaction, thereby forming a cured resin film. Even if the reactive compound before curing is a monomer or an oligomer, they may be collectively referred to as a curable binder resin. The photosensitive layer will be described below.

<About cured resin layer>
When forming the photosensitive layer, first, a reactive compound having at least a charge transporting structure on the conductive support, that is, a reactive monomer or oligomer and a reactive compound having a charge transporting structure are the main components. A layer is formed, and this is sufficiently cured to form a cured layer. Here, curing is generally an intermolecular reaction of a low molecular compound having a plurality of functional groups, or a high molecular compound is bonded between molecules by applying energy such as heat, light, or electron beam (for example, covalent bond). The reaction forms a three-dimensional network structure.
Examples of the curable binder resin include a thermosetting resin that is polymerized by heat, a photocurable resin that is polymerized by light such as ultraviolet rays and visible light, and an electron beam curable resin that is polymerized by electronic properties. It is used in combination with an agent, a catalyst, a polymerization initiator and the like.

  In order to cure a reactive compound having no charge transporting structure and a reactive compound having a charge transporting structure, the reactive compound (for example, monomer or oligomer) has a functional group that causes a polymerization reaction. It is necessary to do. These functional groups include, for example, groups having a carbon-carbon double bond such as acryloyl group, methacryloyl group and vinyl group, groups causing a ring-opening polymerization such as silanol group and cyclic ether group, or two or more kinds of molecules. The one by reaction is mentioned. Further, in the curing reaction, the larger the number of functional groups in one molecule of the reactive monomer, the stronger the three-dimensional network structure becomes, and the trifunctional or higher functionality is particularly effective. As a result, the curing density is increased, the hardness is high, the elasticity is high, the uniformity is smooth, and the smoothness is improved. This is effective for improving the durability and image quality of the photoreceptor.

  The cured layer in the present invention may be a layer in which a reactive compound having no charge transport structure and a reactive compound having a charge transport structure are cured, and conventionally known materials can be used. Regardless of this, a high effect can be obtained.

  Examples of curable binder resins made of reactive monomers and oligomers that do not have the above charge transport structure include phenol resins, epoxy resins, melamine resins, polyester resins, alkyd resins, urethane resins, amino resins, polyimide resins, and siloxane resins. , Acrylic resins, and the like, and urethane resins, phenol resins, acrylic resins, siloxanes, epoxy resin resins, and the like are particularly preferably used. These curable binder resins are characterized in that a three-dimensional network structure is formed and insoluble in an organic solvent. Therefore, in the present invention, the state in which the curable binder resin is cured can be determined to be cured if, for example, the film does not dissolve even when an alcohol-based organic solvent is attached.

  In the present invention, as described above, a reactive monomer or oligomer that does not have a charge transporting structure and a reactive compound having a charge transporting structure are subjected to a curing reaction on the conductive support and developed three-dimensionally. A network structure is formed. In this case, it is possible to further increase the degree of curing by previously mixing a curing agent, a catalyst, a polymerization initiator and the like, which is particularly effective in the present invention. As a result, the wear resistance of the cured layer is further improved, and unreacted functional groups are less likely to remain, which is effective in improving the wear resistance and suppressing the deterioration of electrostatic characteristics. In addition, since the reaction is uniform, cracks and distortions are less likely to occur, and the cleaning property can be improved. For example, it is possible to obtain high effects for improving the durability and image quality of the photoreceptor.

On the other hand, the reactive compound having a charge transporting structure may be any compound that has a functional group for reacting with a reactive compound that does not have the charge transporting structure and includes a structure exhibiting a charge transporting property. Conventionally known materials can be used. The charge transporting structure is a structure contained in the charge transporting substance, and thereby refers to a structure that expresses the charge transporting property. The charge transport structure is mainly classified into a structure that transports holes and a structure that transports electrons, and both are included in the present invention.
There may be one or more charge transporting structures, that is, a hole transporting structure or an electron transporting structure in the compound, and a plurality of structures are more preferable because of excellent charge transporting properties. In addition, it may be effective to have a bipolar property in which both a hole transporting structure and an electron transporting structure are included in the molecule of the reactive compound having a charge transporting structure.

  Among the charge transport structures, examples of the hole transport structure include poly-N-vinyl carbazole, poly-γ-carbazolyl ethyl glutamate, pyrene-formaldehyde condensate, polyvinyl pyrene, polyvinyl phenanthrene, polysilane, oxazole, oxa Diazole, imidazole, monoarylamine, diarylamine, triarylamine, stilbene, α-phenylstilbene, benzidine, diarylmethane, triarylmethane, 9-styrylanthracene, pyrazoline, divinylbenzene, hydrazone, indene, butadiene, pyrene, Examples of the structure generally show electron donating properties such as bisstilbene and enamine.

  On the other hand, examples of the electron transporting structure include chloroanil, bromoanil, 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-trinitrodibenzothiophene-5,5-dioxide, condensed polycyclic quinone, diphenoquinone, benzoquinone, naphthalenetetracarboxylic acid diimide, aromatic ring having cyano group or nitro group, etc. Can be mentioned.

Next, an acrylic resin will be described as an example of the curable binder resin.
Acrylic resins are preferred because they are excellent in wear resistance and excellent in the injectability of charge generation materials and charge transport materials through supercritical fluids and / or subcritical fluids. In order to cure the acrylic resin, a monomer or oligomer having a radical polymerizable functional group having no charge transporting structure and a radical polymerizable compound having a charge transporting structure are used. The radical polymerizable functional group can be appropriately selected and used as long as it has a carbon-carbon double bond and can be radically polymerized. Examples thereof include 1-substituted ethylene functional groups and 1,1-substituted ethylene functional groups shown below.

An example of the 1-substituted ethylene functional group is described below.
(A) 1-substituted ethylene functional group:
Examples of the 1-substituted ethylene functional group include functional groups represented by the following general formula (1).

[In the formula (1), X ₁ represents an arylene group such as a phenylene group or a naphthylene group optionally having a substituent, an alkenylene group optionally having a substituent, a —CO— group, — COO- group, -CON (R ₁₀₎ - group (R ₁₀ is hydrogen, alkyl group such as a methyl group, an ethyl group, a benzyl group, naphthylmethyl group, an aralkyl group such as a phenethyl group, a phenyl group, a naphthyl group Represents an aryl group) or -S- group. ]

  Specific examples of the functional group represented by the general formula (1) include vinyl group, styryl group, 2-methyl-1,3-butadienyl group, vinylcarbonyl group, acryloyloxy group, acryloylamide group, vinylthioether. Groups and the like.

Next, an example of the 1,1-substituted ethylene functional group is described below.
(B) 1,1-substituted ethylene functional group:
Examples of the 1,1-substituted ethylene functional group include a functional group represented by the following general formula (2).

[In the formula (2), Y represents an alkyl group which may have a substituent, an aralkyl group which may have a substituent, a phenyl group which may have a substituent, or a naphthyl group. An aryl group such as a halogen atom, a cyano group, a nitro group, an alkoxy group such as a methoxy group or an ethoxy group, a —COOR ₁₁ group (R ₁₁ is a hydrogen atom, an optionally substituted methyl group, an ethyl group) An alkyl group such as benzyl, an aralkyl group such as a phenethyl group, an aryl group such as a phenyl group or a naphthyl group optionally having a substituent, or -CONR ₁₂ R ₁₃ (R ₁₂ and R ₁₃ are each a hydrogen atom, an alkyl group such as an optionally substituted methyl group or an ethyl group, an aralkyl group such as an optionally substituted benzyl group, naphthylmethyl group, or phenethyl group. Group, Other phenyl group which may have a substituent, an aryl group such as phenyl or naphthyl, which may be the same or different from each other.) Further, X ₂ is identical to X ₁ in the general formula (1) And at least one of Y and X ₂ is an oxycarbonyl group, a cyano group, an alkenylene group, or an aromatic ring.]

  Specific examples of the functional group 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 with the substituent for X ₁ , X ₂ , and Y include, for example, halogen groups, nitro groups, cyano groups, methyl groups, ethyl groups and other alkyl groups, methoxy groups, ethoxy groups, and the like. Examples thereof include aryloxy groups such as alkoxy groups and phenoxy groups, aryl groups such as phenyl groups and naphthyl groups, and aralkyl groups such as benzyl groups and phenethyl groups. Among these radical polymerizable functional groups, acryloyloxy group and methacryloyloxy group are particularly useful.

  The number of functional groups of the radically polymerizable monomer or oligomer having no charge transporting structure is preferably polyfunctional and more preferably trifunctional or higher. When trifunctional or higher-functional radically polymerizable monomers are cured, a three-dimensional network structure is developed, and a high hardness and high elasticity layer having a very high crosslink density is obtained. And scratch resistance are achieved. However, depending on the curing conditions and the materials used, a large number of bonds are instantaneously formed in the curing reaction, so that internal stress due to volume shrinkage occurs, and cracks and film peeling may easily occur. In that case, it may be improved by using a monofunctional or bifunctional radically polymerizable monomer or by mixing them. Hereinafter, a radical polymerizable monomer having no tri- or higher functional charge transport structure effective for improving the wear resistance will be described.

  A compound having 3 or more acryloyloxy groups may be subjected to an ester reaction or a transesterification reaction using, for example, a compound having 3 or more hydroxyl groups in the molecule and acrylic acid (salt), acrylic acid halide, or acrylic ester. Can be obtained. A compound having three or more methacryloyloxy groups can be obtained in the same manner. Further, the radical polymerizable functional groups in the monomer having three or more radical polymerizable functional groups may be the same or different.

Specific examples of the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure include the following, but are not limited to these compounds.
That is, examples of the radical polymerizable monomer used in the present invention include trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, trimethylolpropane alkylene-modified triacrylate, trimethylolpropane ethyleneoxy-modified (hereinafter referred to as EO). Modified) triacrylate, trimethylolpropane propyleneoxy modified (hereinafter PO modified) triacrylate, trimethylolpropane caprolactone modified triacrylate, trimethylolpropane alkylene modified trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol Triacrylate, glycerol epichlorohydrin modification (hereinafter ECH modification) ) Triacrylate, glycerol EO modified triacrylate, glycerol PO modified triacrylate, tris (acryloxyethyl) isocyanurate, dipentaerythritol hexaacrylate (DPHA), dipentaerythritol caprolactone modified hexaacrylate, dipentaerythritol hydroxypentaacrylate, alkyl Dipentaerythritol pentaacrylate, alkylated dipentaerythritol tetraacrylate, alkylated dipentaerythritol triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, phosphoric acid EO-modified triacrylate, 2,2,5 , 5, -Tetrahydroxymethylcyclopentanone tetraac Rate, and the like, it may be used alone or in combination.

  In addition, a tri- or higher functional radical polymerizable monomer having no charge transport structure has a molecular weight ratio (molecular weight / functional group number) to the functional group number in the monomer in order to form a dense cross-linking bond in the photosensitive layer. Is preferably 250 or less. If this ratio is larger than 250, the photosensitive layer is soft and wear resistance is somewhat lowered. Therefore, among monomers exemplified above, monomers having a modifying group such as EO, PO, and caprolactone are extremely long modified. It may be difficult to use a group having a group alone.

  The proportion of the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure is 20 to 80% by weight, preferably 30 to 70% by weight, based on the total amount of the photosensitive layer. When the monomer component is less than 20% by weight, the three-dimensional cross-linking density is small, and a drastic improvement in wear resistance is not achieved as compared with the case of using a conventional thermoplastic binder resin. On the other hand, if it is 80% by weight or more, the content of the reactive compound having a charge transporting structure is lowered, and the electrostatic characteristics are deteriorated. The required electrostatic characteristics and abrasion resistance differ depending on the process used, but the range of 30 to 70% by weight is most preferable in consideration of the balance of both characteristics.

Next, a radical polymerizable compound having a charge transporting structure, which is one of reactive compounds having a charge transporting structure, will be described.
The radical polymerizable compound having a charge transporting structure in the present invention has a hole transporting structure such as the aforementioned triarylamine, hydrazone, pyrazoline, carbazole, etc., for example, a condensed polycyclic quinone, diphenoquinone, a cyano group or a nitro group. It is a compound having either or both of electron transport structures such as an electron-withdrawing aromatic ring and having a radical polymerizable functional group.

  Examples of the radical polymerizable functional group include those shown in the above radical polymerizable monomer, and acryloyloxy group and methacryloyloxy group are particularly useful. The number of functional groups of the radical polymerizable compound having a charge transporting structure is most preferably monofunctional. Thereby, electrostatic characteristics are improved, and stability in repeated use can also be improved. In the case of two or more functional groups, a plurality of bonds are fixed in the cross-linked structure and the cross-link density is further increased. However, the charge transport structure is very bulky, and thus the distortion of the cured resin structure increases and the internal stress of the layer increases. Become. In addition, the intermediate structure (cation radical) at the time of charge transport cannot be kept stable, and the sensitivity is lowered and the residual potential is easily increased due to charge trapping.

  As these charge transporting structures, a triarylamine structure has a high effect and is effectively used in the present invention. In particular, when a compound represented by the structure of the following general formula (3) or (4) is used, electrostatic properties such as sensitivity and residual potential are well maintained and effective.

[In the formulas (3) and (4), R ₁ may have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Aryl group, cyano group, nitro group, alkoxy group, —COOR ₇ (R ₇ has a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. An aryl group), a halogenated carbonyl group or CONR ₈ R ₉ (R ₈ and R ₉ are a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl which may have a substituent) Represents an aryl group which may have a group or a substituent and may be the same or different from each other), Ar ₁ and Ar ₂ represent a substituted or unsubstituted arylene group and are the same May be different. Ar ₃ and Ar ₄ represent a substituted or unsubstituted aryl group, and may be the same or different. X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group. Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, or an alkyleneoxycarbonyl divalent group. m and n represent an integer of 0 to 3. ]

Specific examples of those represented by the general formulas (1) and (2) are shown below.
In the general formulas (1) and (2), in the substituent of R ₁ , examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the aryl group include a phenyl group and a naphthyl group. However, examples of the aralkyl group include a benzyl group, a phenethyl group, and a naphthylmethyl group, and examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group. These include a halogen atom, a nitro group, and a cyano group. An alkyl group such as a methyl group or an ethyl group, an alkoxy group such as a methoxy group or an ethoxy group, an aryloxy group such as a phenoxy group, an aryl group such as a phenyl group or a naphthyl group, an aralkyl group such as a benzyl group or a phenethyl group, etc. May be substituted. Of the substituents for R ₁ , particularly preferred are a hydrogen atom and a methyl group.

Ar _3, Ar ₄ substituted or unsubstituted is an aryl group, the aryl group condensed polycyclic hydrocarbon groups include unfused 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-fused cyclic hydrocarbon group include monovalent groups of monocyclic hydrocarbon compounds such as benzene, diphenyl ether, polyethylene diphenyl ether, diphenyl thioether and diphenyl sulfone, or biphenyl, polyphenyl, diphenylalkane, diphenylalkene, diphenylalkyne, Monovalent groups of non-condensed polycyclic hydrocarbon compounds such as triphenylmethane, distyrylbenzene, 1,1-diphenylcycloalkane, polyphenylalkane, and polyphenylalkene, or ring assemblies such as 9,9-diphenylfluorene And monovalent groups of hydrocarbon compounds.

Examples of the heterocyclic group include monovalent groups such as carbazole, dibenzofuran, dibenzothiophene, oxadiazole, and thiadiazole.
The aryl group represented by Ar ₃ or Ar ₄ may have a substituent as shown below, for example.

[1] Halogen atom, cyano group, nitro group and the like can be mentioned.
[2] Alkyl groups, preferably C _{1 to} C _12, especially C _{1 to} C ₈ , more preferably C _{1 to} C ₄ linear or branched alkyl groups, and these alkyl groups further include a fluorine atom , a hydroxyl group, a cyano _group, an alkoxy group of C 1 -C _4, a phenyl group or a halogen _atom, which may have a phenyl group substituted by an alkoxy group C 1 -C ₄ alkyl or _C 1 -C ₄ Good. Specifically, methyl group, ethyl group, n-butyl group, i-propyl group, t-butyl group, s-butyl group, n-propyl group, trifluoromethyl group, 2-hydroxyethyl group, 2-ethoxyethyl Group, 2-cyanoethyl group, 2-methoxyethyl group, benzyl group, 4-chlorobenzyl group, 4-methylbenzyl group, 4-phenylbenzyl group and the like.
[3] An alkoxy group (—OR ₂ ), and R ₂ represents the alkyl group defined in [2]. Specifically, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, t-butoxy group, n-butoxy group, s-butoxy group, i-butoxy group, 2-hydroxyethoxy group, benzyloxy group And a trifluoromethoxy group.
[4] An aryloxy group, and examples of the aryl group include a phenyl group and a naphthyl group. It may contain an alkoxy group having _C 1 -C _4, alkyl group, or a halogen atom C 1 -C ₄ as a substituent. Specific examples include a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a 4-methoxyphenoxy group, and a 4-methylphenoxy group.
[5] Alkyl mercapto group or aryl mercapto group, and 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 (5).

[In Formula (5), R ₃ and R ₄ each independently represents a hydrogen atom, an alkyl group defined in the above [2], or an aryl group. Examples of the aryl group include a phenyl group, and a biphenyl group or a naphthyl group, which may contain an alkoxy group of C ₁ -C _4, alkyl group, or a halogen atom C ₁ -C ₄ as a substituent . R ₃ and R ₄ may form a ring together. ]

  Specifically, amino group, diethylamino group, N-methyl-N-phenylamino group, N, N-diphenylamino group, N, N-di (tolyl) amino group, dibenzylamino group, piperidino group, morpholino group And pyrrolidino group.

  [7]: An alkylenedioxy group or an alkylenedithio group such as a methylenedioxy group or a methylenedithio group.

  [8]: Substituted or unsubstituted styryl group, substituted or unsubstituted β-phenylstyryl group, diphenylaminophenyl group, ditolylaminophenyl group, and the like.

In the general formulas (3) and (4), the substituted or unsubstituted arylene group represented by Ar ₁ or Ar ₂ is a divalent group derived from the aryl group represented by Ar ₃ or Ar _4. Is mentioned.

  In the general formula (3), X is a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, as described above. Represents a vinylene group.

The substituted or unsubstituted alkylene group is a C _{1 to} C ₁₂ , preferably C _{1 to} C ₈ , more preferably C _{1 to} C ₄ linear or branched alkylene group. a fluorine atom, a hydroxyl group, organic cyano _group, an alkoxy group of C 1 -C _4, a phenyl group or a halogen _atom, a phenyl group substituted with an alkyl group or a _C 1 -C ₄ alkoxy group C 1 -C ₄ You may do it.
Specifically, methylene group, ethylene group, n-butylene group, i-propylene group, t-butylene group, s-butylene group, n-propylene group, trifluoromethylene group, 2-hydroxyethylene group, 2-ethoxyethylene Group, 2-cyanoethylene group, 2-methoxyethylene group, benzylidene group, phenylethylene group, 4-chlorophenylethylene group, 4-methylphenylethylene group, 4-biphenylethylene group and the like.

The substituted or unsubstituted cycloalkylene _group, a cyclic alkylene group of C 5 -C _7, these are the cyclic alkylene group fluorine atom, a hydroxyl _group, an alkyl group of C 1 -C _4, a C 1 -C ₄ It may have an alkoxy group. Specific examples include a cyclohexylidene group, a cyclohexylene group, and a 3,3-dimethylcyclohexylidene group.

The substituted or unsubstituted alkylene ether group represents ethyleneoxy, propyleneoxy, ethylene glycol, propylene glycol, diethylene glycol, tetraethylene glycol, tripropylene glycol, and the alkylene ether group alkylene group is a hydroxyl group, a methyl group, an ethyl group, etc. You may have the substituent of.
Examples of the vinylene group include groups represented by the following general formula (6) or general formula (7).

[In the general formulas (6) and (7), R ₅ represents hydrogen, an alkyl group (the same as the alkyl group defined in [2] above), an aryl group (the aryl group defined by Ar ₃ and Ar ₄ above) The same), a represents 1 or 2, and b represents an integer of 1 to 3. ]

Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, or an alkyleneoxycarbonyl divalent group.
Examples of the substituted or unsubstituted alkylene group include the same alkylene groups as those described above for X. Examples of the substituted or unsubstituted alkylene ether divalent group include the divalent group of the alkylene ether group of X.
Examples of the alkyleneoxycarbonyl divalent group include a caprolactone-modified divalent group.
Further, the radically polymerizable compound having a monofunctional charge transport structure of the present invention is more preferably a compound having a structure represented by the following general formula (8).

  [In the general formula (8), o, p and q are each an integer of 0 or 1, Ra represents a hydrogen atom or a methyl group, Rb and Rc are substituents other than a hydrogen atom and an alkyl group having 1 to 6 carbon atoms. And a plurality of cases may be different. s and t represent an integer of 0 to 3. Za represents a single bond, a methylene group, an ethylene group, or a divalent group represented by the following formulas (a), (b), and (c). ]

  As the compound represented by the general formula (8), compounds having a methyl group or an ethyl group are particularly preferable as substituents for Rb and Rc.

  The radically polymerizable compound having a monofunctional charge transport structure represented by the general formulas (3) and (4), particularly (8) used in the present invention is polymerized by opening a carbon-carbon double bond on both sides. Therefore, in a polymer that is not a terminal structure but is incorporated in a chain polymer and crosslinked by polymerization with a tri- or higher functional radical polymerizable monomer, it exists in the main chain of the polymer, and Present in the cross-linked chain between the chain and the main chain (this cross-linked chain has an intermolecular cross-linked chain between one polymer and another polymer, and a site where the main chain is folded in one polymer. And other intramolecular cross-linked chains that are cross-linked with other sites derived from the polymerized monomer at positions away from this in the main chain), but even if they are present in the main chain, Even if present, the triarylamine structure suspended from the chain moiety is It has at least three aryl groups arranged in the radial direction and is bulky, but is not directly bonded to the chain part, but is suspended from the chain part via a carbonyl group, etc. Since these triarylamine structures can be arranged adjacent to each other in the polymer, there is little structural distortion in the molecule, and the surface of the electrophotographic photosensitive member is also fixed. In the case of a layer, it is presumed that an intramolecular structure that is relatively free from interruption of the charge transport pathway can be adopted.

  Specific examples of the radical polymerizable compound having a monofunctional charge transporting structure of the present invention are as follows. 1-No. Although shown in the structural formula 160, it is not limited to compounds having these structures.

  The radical polymerizable compound having a monofunctional charge transport structure used in the present invention is important for imparting charge transport performance, and this component is 20 to 80% by weight, preferably 30%, based on the photosensitive layer. ~ 70 wt%. If this component is less than 20% by weight, the charge transport performance cannot be sufficiently maintained, and deterioration of electrical characteristics such as a decrease in sensitivity and an increase in residual potential appear after repeated use. On the other hand, when the content is 80% by weight or more, the content of the monomer having no charge transport structure is lowered, the crosslinking density is lowered, and high wear resistance is not exhibited. The required electrostatic characteristics and abrasion resistance differ depending on the process used, but the range of 30 to 70% by weight is most preferable in consideration of the balance of both characteristics.

  The cured layer of the present invention can be prepared by curing a radically polymerizable monomer having no charge transporting structure and a radically polymerizable compound having a charge transporting structure. Monofunctional is preferred, but the former is monofunctional and bifunctional radically polymerizable monomer for the purpose of imparting functions such as viscosity adjustment during coating, stress relaxation of the crosslinkable charge transport layer, lower surface energy and reduced friction coefficient. And radically polymerizable oligomers can be used in combination. Known radical polymerizable monomers and oligomers can be used.

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

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

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

  The content of these monomers and oligomers is 50 parts by weight or less, preferably 30 parts by weight or less, based on 100 parts by weight of a tri- or higher functional radical polymerizable monomer.

Moreover, in order to advance a curing reaction efficiently as needed, you may contain polymerization initiators, such as a thermal-polymerization initiator and a photoinitiator, in the coating liquid which forms a cured resin layer.
Examples of the thermal polymerization initiator include 2,5-dimethylhexane-2,5-dihydroperoxide, dicumyl peroxide, benzoyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5. -Di (peroxybenzoyl) hexyne-3, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, lauroyl peroxide, 2,2-bis (4,4-di-t-butyl Peroxycyclohexyl) propane, peroxide initiators, azobisisobutyronitrile, azobiscyclohexanecarbonitrile, methyl azobisisobutyrate, azobisisobutylamidine hydrochloride, 4,4′-azobis-4-cyanovaleric acid An azo-based initiator such as

  On the other hand, examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, and 4- (2-hydroxyethoxy). ) Phenyl- (2-hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1,2-hydroxy-2-methyl-1-phenylpropane-1 -One, 2-methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, acetophenone or ketal Photopolymerization initiator, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin Benzoin ether photopolymerization initiators such as sobutyl ether, benzoin isopropyl ether, benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoylphenyl ether, acrylated benzophenone Benzophenone photopolymerization initiators such as 1,4-benzoylbenzene, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, etc. Thioxanthone photopolymerization initiator, ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphos Zinc oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10-phenanthrene, Other photopolymerization initiators such as acridine compounds, triazine compounds, and imidazole compounds can be mentioned.

A substance having a photopolymerization promoting effect can also be used. Examples of the substance having a photopolymerization promoting effect include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, 4,4 ′. -Dimethylaminobenzophenone, etc.
These may be used alone or in combination with the photopolymerization initiator. The said polymerization initiator may be used individually by 1 type, and 2 or more types may be mixed and used for it. As content of the said polymerization initiator, it is preferable that it is 0.5-40 weight part with respect to 100 weight part of total content which has radical polymerizability, and it is more preferable that it is 1-20 weight part.

Next, one type of urethane resin will be described as an example of the curable binder resin.
Urethane resin has high wear resistance, good electrostatic properties, excellent film quality, and is effective for enhancing the durability and image quality of the photoreceptor. As an example, the urethane resin can be formed by combining a polyol that is an active hydrogen component and a polyvalent isocyanate that is a curing agent.

  Polyols include polyether polyols such as polyalkylene oxides, polyester polyols such as aliphatic polyesters having a hydroxyl group at the end, acrylic polymer polyols such as hydroxymethacrylate copolymers, epoxy polyols such as epoxy resins, fluorine-containing polyols In addition, known ones such as polycarbonate diol having a polycarbonate skeleton can be exemplified.

  In addition, a technique for preventing deterioration of a cured resin and suppressing reduction in resolution of a photoreceptor by using a polyol having a hindered amine skeleton is disclosed (Japanese Patent No. 3818584), and can be used well in the present invention. Hindered amines are known as light stabilizers and antioxidants. By curing a polyol having this structure, a hindered amine structure can be introduced into the cured resin, thereby obtaining a stabilizing effect. Moreover, these can be used in mixture of 2 or more types of polyols, and are effective. An example of a hindered amine structure is shown in the following structural formula (HA).

  The polyol is preferably bifunctional or more, preferably trifunctional or more, because the curing density is improved, the three-dimensional network structure is strengthened, and as a result, the curability is increased and the film strength is increased. As the molecular weight of the polyol, those having a molecular weight of 100 to 150 are widely used. However, depending on the curing conditions, the volume shrinkage becomes large and the film quality may be deteriorated. In this case, in order to alleviate the volume shrinkage at the time of curing, a method of curing by separately containing a polyol having a molecular weight of 1000 or more is disclosed (Japanese Patent No. 3818585 etc.) and can be applied well in the present invention. .

On the other hand, general isocyanate materials can be used as the polyvalent isocyanate of the curing agent. However, since it is used as a photosensitive layer, it is preferable that the film does not discolor over time. Examples include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), xylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), bis (isocyanatomethyl) cyclohexane (HXDI), trimethylhexamethylene diisocyanate. (TMDI) and other isocyanate compounds, HDI-trimethylolpropane adduct, HDI-isocyanate, HDI-biuret, XDI-trimethylolpropane adduct, IPDI-trimethylolpropane adduct, IPDI-isocyanurate, etc. A well-known thing, such as isocyanate, can be illustrated.
Examples of the isocyanate having an amide bond used in the present invention include known ones such as HDI-trimethylolpropane adduct, IPDI-trimethylolpropane adduct, HDI-biuret, and these can be used alone or in combination. . The ratio of the number of NCO groups of isocyanate to the number of OH groups of polyol (NCO / OH ratio) is preferably about 1.0 to 1.5.

  As the reactive compound having a charge transporting structure, a conventionally known material can be used as long as it has the above-described charge transporting structure and a functional group for curing reaction with polyol, isocyanate and the like in the same structure. As described above, the charge transporting structure may include either or both of the hole transporting property and the electron transporting property, and among them, a compound having a triarylamine structure is particularly effective. Moreover, a hydroxyl group is common as a functional group for the curing reaction. An example of a reactive compound having a triphenylamine structure is shown below.

Next, a curable siloxane resin will be briefly described as an example of the curable binder resin.
The curable siloxane resin is also excellent in wear resistance and can be effectively used because it is excellent in the injection property of the charge generation material and the charge transport material by the supercritical fluid and / or the subcritical fluid.
A curable siloxane resin forms a three-dimensional network structure by reacting in advance with monomers, oligomers, and polymers having a siloxane bond in the structural unit (including hydrolysis reaction, reaction with addition of a catalyst and a crosslinking agent, etc.) and cured. Resin. In general, a cured resin layer made of a siloxane resin is formed by promoting a siloxane bond by hydrolyzing an organosilicon compound having a siloxane bond and subsequent dehydration condensation to form a three-dimensional network structure. For example, a three-dimensional network structure is formed by a condensation reaction of a composition composed of alkoxysilane or a composition composed of alkoxysilane and colloidal silica to form a cured layer.

As a raw material for the curable siloxane resin, an organosilicon compound having a hydroxyl group or a hydrolyzable group is generally used.
Examples of the hydrolyzable group in the organosilicon compound having a hydroxyl group or a hydrolyzable group include a methoxy group, an ethoxy group, a methylethylketoxime group, a diethylamino group, an acetoxy group, a propenoxy group, a propoxy group, a butoxy group, and a methoxyethoxy group. It is done. Among them, a hydrolyzable group represented by —OR is preferable, R is an atomic group forming an alkoxy group, and preferably has 1 to 6 carbon atoms.

  The organosilicon compound used as a raw material for the curable siloxane resin generally has different reactivity depending on the number of hydrolyzable groups bonded to silicon atoms. When the number of hydrolyzable groups is 1, the crosslinking density is small and curing is insufficient, and the polymerization reaction of the organosilicon compound is suppressed, but when 2, 3, or 4, the polymerization reaction is likely to occur. In particular, the crosslinking reaction can be advanced to a high degree of 3 to 4. However, even if it is sufficient, the film may become brittle. Therefore, it is preferable to use a mixture of a component having a small amount of a hydrolyzable group and a component having a large amount. In addition, as a raw material for the siloxane-based resin, a hydrolysis condensate obtained by oligomerizing the organosilicon compound by hydrolysis under an acidic condition or a basic condition can also be used.

  As the reactive compound having a charge transporting structure, conventionally known materials can be used as long as they have the above-described charge transporting structure and a functional group for curing reaction with a siloxane resin in the same structure. As described above, the charge transporting structure may include either or both of the hole transporting property and the electron transporting property, and among them, a compound having a triarylamine structure is particularly effective. As the functional group for the curing reaction, a hydroxyl group, an amino group, a mercapto group, or an alkoxysilyl group is generally used.

Next, a phenol resin (curable phenol resin) will be briefly described as the curable binder resin. The curable phenol resin is a resin generally obtained by a reaction between phenols and formaldehyde. There are two types of phenolic resins: a resol type obtained by reacting with phenol with an excess of formaldehyde and an alkali catalyst, and a novolak obtained by reacting with an acid catalyst with an excess of phenol with respect to formaldehyde Divided into molds.
The resol type is also soluble in alcohol and ketone solvents, and is three-dimensionally crosslinked and polymerized by heating to form a cured product. On the other hand, the novolak type generally does not cure even when heated as it is, but forms a cured product by adding a formaldehyde source such as paraformaldehyde or hexamethylenetetramine and heating.

  The phenol resin in the present invention can be used in either the above-mentioned resol type or novolac type, but it can be cured without adding a curing agent, or it can be resol type because it is one-part and operability as a paint. It is preferable to use it. The resol type is soluble in alcohol and ketone solvents, and is cured by three-dimensional cross-linking polymerization by heating. These phenol resins can be used alone or in combination of two or more, and a resol type and a novolac type can also be used in combination.

  As the reactive compound having a charge transporting structure, conventionally known materials can be used as long as they have the above-described charge transporting structure and a functional group for curing reaction with a phenol resin in the same structure. As described above, the charge transporting structure may include either or both of the hole transporting property and the electron transporting property, and among them, a compound having a triarylamine structure is particularly effective. As the functional group for the curing reaction, a hydroxyl group, a carboxyl group, an alkoxysilyl group, an epoxy group, a carbonate group, a thiol group, an amino group, or the like is generally used.

  As the epoxy resin, bisphenol A type, bisphenol F type, bisphenol AD type, bromide epoxy resin, novolac epoxy resin, cycloaliphatic epoxy resin, glycidyl ester resin, glycidyl acyl resin and heterocyclic epoxy resin are known. In the present invention, these known epoxy resins can be used. Examples of epoxy resin curing agents include acid anhydrides (phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylmedicic anhydride, methyltetrahydrophthalic anhydride, succinic anhydride, maleic anhydride, and pyromellitic anhydride. , Trimellitic anhydride), acyl-based curing agents (aliphatic amines, aromatic primary amines, tertiary amine-based curing agents, modified polyamines), dicyandiamide, and organic acid dihydrazides can be used.

  As the reactive compound having a charge transporting structure, conventionally known materials can be used as long as they have the above-described charge transporting structure and a functional group for curing reaction with a phenol resin in the same structure. As described above, the charge transporting structure may include either or both of the hole transporting property and the electron transporting property, and among them, a compound having a triarylamine structure is particularly effective. Examples of the functional group for the curing reaction include a hydroxyalkyl group, a hydroxyalkoxy group, a hydroxyalkylthio group, and a hydroxyphenyl group which may have a substituent.

  As described above, there are many examples of using the curable binder resin in the photosensitive layer of the photoreceptor, but the invention is not limited thereto, and in the present invention, any conventionally known curable resin can be used satisfactorily. It is valid. However, in the present invention, a resin film containing these curable binder resins as a main component is formed and sufficiently cured, and then a charge generation material or a charge transport material is injected into the cured layer. There is a great difference from a conventionally known technique in which a curing reaction is carried out in a state in which these charge generation material and charge transport material are contained in a resin film.

<About charge generation materials>
A charge generating material and a charge transport material are contained in a supercritical fluid and / or a subcritical fluid and brought into contact with the above-described cured resin layer, whereby the charge generating material and the charge transport material are injected into the cured resin layer. These charge generation materials and charge transport materials will be described below.
A conventionally known material can be used as the charge generation material used in the present invention.
For example, azo pigments such as monoazo pigments, disazo pigments, asymmetrical disazo pigments, trisazo pigments (for example, JP-A Nos. 54-22834 and 61-151659), titanyl phthalocyanine, copper phthalocyanine, vanadyl phthalocyanine, Phthalocyanine pigments such as hydroxygallium phthalocyanine, chlorogallium phthalocyanine, aluminum phthalocyanine, magnesium phthalocyanine, chloroindium phthalocyanine, hydroxyindium phthalocyanine, zinc phthalocyanine, iron phthalocyanine, cobalt phthalocyanine, and metal-free phthalocyanine (for example, JP-A-48-34189) JP, 57-14874, etc.), other perylene pigments (for example, JP 53-98825, JP 6) No. -266457), perinone pigments, quinone condensed polycyclic compounds (for example, JP-A 61-48861), indigo pigments, pyrrolopyrrole pigments, anthraquinone pigments, quinacridone pigments, quinoneimine pigments, diphenylmethane and triphenyl Examples thereof include phenylmethane pigments, squalium pigments (for example, JP-A-49-105536 and JP-A-58-21416), cyanine and azomethine pigments, and bisbenzimidazole pigments. Among azo pigments, azo pigments having a carbazole skeleton (Japanese Patent Laid-Open No. 53-95033), azo pigments having a triphenylamine skeleton (Japanese Patent Laid-Open No. 53-132347), and azo pigments having a distyrylbenzene skeleton. Pigments (Japanese Patent Laid-Open No. 53-133445), azo pigments having a dibenzothiophene skeleton (Japanese Patent Laid-Open No. 54-21728), azo pigments having a fluorenone skeleton (Japanese Patent Laid-Open No. 54-22834), oxadiazole Azo pigments having a skeleton (Japanese Patent Laid-Open No. 54-12742), azo pigments having a bis-stilbene skeleton (Japanese Patent Laid-Open No. 54-17733), azo pigments having a distyryloxadiazole skeleton (Japanese Patent Laid-Open No. 54-57 2129), azo pigments having a distyrylcarbazole skeleton (Japanese Patent Laid-Open No. 54-14967) Also preferably used. These charge generation materials may be used alone or in combination of two or more.

  Among these charge generation materials, azo pigment compounds and phthalocyanine pigment compounds are suitable. However, in the case of a phthalocyanine pigment, depending on the type or processing conditions thereof, the crystal form may become unstable when it is contained in a supercritical fluid and / or a subcritical fluid. In this case, the influence can be reduced by adjusting the temperature and pressure conditions of the supercritical fluid and / or subcritical fluid, but the azo pigment compound is more preferably used because it can be used more stably.

  In the present invention, it is more preferable to use those obtained by bringing these charge generation materials into contact with a supercritical fluid and / or a subcritical fluid in advance. By this method, impurities contained in the charge generation material are removed, and a higher purity charge generation material can be contained in the layer. As a method for cleaning and purifying a charge generating substance using a supercritical fluid and / or a subcritical fluid, a conventionally known method can be used (for example, JP-A-7-181694, JP-A-2001-92165, JP 2002-138216 A, JP 2002-356627 A, etc.).

<About charge transport materials>
Charge transport materials are roughly classified into hole transport materials that transport holes and electron transport materials that transport electrons, and a single-layer photosensitive layer is required to have both functions. However, as described above, the cured layer of the present invention is cured by the curable binder resin such as a reactive monomer or oligomer having no charge transporting structure and the reactive compound having a charge transporting structure. As such, it already has a charge transport function.
Therefore, it is only necessary to inject a substance that transports a charge of the opposite polarity. For example, in the case of a cured resin layer cured by a curable binder resin and a reactive compound having a hole transporting structure, the charge generation material and the electron transport material may be injected by a supercritical fluid and / or a subcritical fluid. In the case of a cured layer cured by a curable binder resin and a reactive compound having an electron transporting structure, the charge generation material and the hole transport material may be injected by a supercritical fluid and / or a subcritical fluid. However, for example, even in a cured layer cured with a curable binder resin and a reactive compound having a hole transporting structure, it is possible to inject a hole transporting material together with an electron transporting material to supplement the hole transporting function. And may be effective in terms of electrostatic characteristics.

  An electron transport material injected into the hardened layer by a supercritical fluid and / or a subcritical fluid will be described. As the electron transporting substance, a substance exhibiting electron accepting properties is used, and all conventionally known materials can be applied. For example, chloranil derivatives, bromoanil derivatives, tetracyanoethylene derivatives, tetracyanoquinodimethane derivatives, fluorenone derivatives such as 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, Xanthone derivatives such as 2,4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, diphenoquinone derivatives, benzoquinone derivatives, azoquinone derivatives, monoquinone derivatives, dinaphthylquinone derivatives, stilbenequinone derivatives, anthraquinone derivatives, Phenanthraquinone derivatives, carboxylic acid diimide derivatives, thiopyran derivatives, dinitroanthracene derivatives, dinitroacridine derivatives, nitroanthraquinone derivatives, dinitroanthraquinone derivatives, naphthalene tetraca Electron-accepting substance such as carbon diimide derivatives. These electron transport materials are used alone or in combination of two or more.

  Among these electron transport materials, naphthalene tetracarboxylic acid diimide derivatives (for example, US Pat. No. 4,442,193, US Pat. No. 5,468,583, Patent No. 3292461, Patent No. 3373783, etc.) In addition to being excellent in the properties, it is particularly effective because it is excellent in the injectability when it is contained in the supercritical fluid and / or the subcritical fluid and injected into the hardened layer. The naphthalenetetracarboxylic acid diimide derivative in the present invention is a compound that includes at least a naphthalenetetracarboxylic acid diimide structure represented by the following general formula (10) in an electron transport material.

(In the formula, R _{53 to} R ₅₆ are each independently a hydrogen atom, a halogen atom, a cyano group, a nitro group, an amino group, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a substituent. Alternatively, it represents an unsubstituted cycloalkyl group or a substituted or unsubstituted aralkyl group.)

  In the naphthalenetetracarboxylic acid diimide derivative, a more specific general formula of the electron transport material that can be effectively used in the present invention is represented by the following general formula (11).

[Wherein, R _{57 to} R ₆₀ are each independently a hydrogen atom, a halogen atom, a cyano group, a nitro group, an amino group, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a substituent. Or an unsubstituted cycloalkyl group, a substituted or unsubstituted aralkyl group, and A represents a hydrogen atom, a branched alkyl group, an unsubstituted linear alkyl group, an unsubstituted cyclic alkyl group, an alkyl substituted cyclic alkyl group, an unsubstituted straight chain Represents a chain unsaturated alkyl group, an alkyl group having 2 to 20 carbon atoms, an alkoxy group having 2 to 20 carbon atoms, or a substituted or unsubstituted aryl group, and B represents a hydrogen atom, a branched alkyl group, or an unsubstituted linear alkyl group. Group, unsubstituted cyclic alkyl group, alkyl-substituted cyclic alkyl group, unsubstituted linear unsaturated alkyl group, alkyl group having 2 to 20 carbon atoms, alkoxy group having 2 to 20 carbon atoms, or substituted Or an unsubstituted aryl group or a group represented by the following general formula (12):

(Wherein, R ₆₁ to R ₆₄ is a hydrogen atom, a halogen atom, a cyano group, a nitro group, an amino group, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a substituted or unsubstituted A cycloalkyl group, a substituted or unsubstituted aralkyl group, and C is a hydrogen atom, a branched alkyl group, an unsubstituted linear alkyl group, an unsubstituted cyclic alkyl group, an alkyl substituted cyclic alkyl group, an unsubstituted linear unsaturated group Represents an alkyl group, an alkyl group having 2 to 20 carbon atoms, an alkoxy group having 2 to 20 carbon atoms, or a substituted or unsubstituted aryl group. ]

  Specific examples of electron transport materials (ETM) that are particularly effectively used in the present invention are shown in Tables 1 and 2 below. However, the present invention is not limited to these materials. These electron transport materials can be synthesized by a conventionally known synthesis method. For example, JP-A-2007-108632 and JP-A-2007-108719 can be referred to.

Next, a hole transport material that is injected into the cured resin layer as necessary by the supercritical fluid and / or the subcritical fluid will be described.
As the hole transport material, a material showing an electron donating property is used, and all conventionally known materials can be applied. For example, poly-N-carbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, oxadiazole derivatives, imidazole Derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazoline derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenyl Stilbene derivatives, distyrylbenzene derivatives, aminobiphenyl derivatives, benzidine derivatives, butadiene derivatives, pyrene derivatives, etc. Examples include materials such as conductors and enamine derivatives. These hole transport materials may be used alone or in combination of two or more.
Among these, triarylamine derivatives, particularly triphenylamine derivatives, are effective not only for high stabilization of electrostatic properties, but also when injected into a hardened layer by being contained in a supercritical fluid and / or a subcritical fluid. It is particularly effective because of its excellent properties.
The triphenylamine derivative in the present invention is a compound containing a triphenylamine structure represented by at least the following general formula (13) in the hole transport material.

(Wherein, the R ₁ to R ₁₂ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a substituted or unsubstituted aryl group.)

  In the triphenylamine derivative, a more specific general formula of the hole transport material that can be effectively used in the present invention is represented by the following general formula (14).

[Wherein, m represents any one of 0, 1 or 2, and R _{13 to} R ₂₆ each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Represents a substituted or unsubstituted aryl group, and Ar ₁ represents a substituted or unsubstituted aryl group, the following general formula (15), or the following general formula (16). ]

(Wherein R _{27 to} R ₃₈ each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a substituted or unsubstituted aryl group.)

(Wherein, n represents either 0, 1 or 2, the R ₃₉ to R ₅₂ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms Represents a substituted or unsubstituted aryl group.)

  Specific examples of hole transport materials (HTM) that are particularly effectively used in the present invention are shown in Tables 3 and 4 below. However, the present invention is not limited to these materials.

<About additives>
The photoreceptor of the present invention can contain a substance other than the charge generation substance and the charge transport substance in the photosensitive layer, and is effective for stabilization of electrostatic characteristics. Examples of these additives include additives such as antioxidants, plasticizers, lubricants, ultraviolet absorbers, light stabilizers, inorganic fine particles such as metal oxides, and organic fine particles such as fluororesins or silicone resins. A filler, a resistance control agent, etc. are mentioned, It is not limited to this.

  If the additive is contained in the supercritical fluid and / or subcritical fluid together with the charge generation material or charge transport material and brought into contact with the cured resin layer, it is injected into the cured resin layer together with the charge generation material or charge transport material. Is done. Since it is possible to add additives to the cured layer later, it does not cause inhibition of curing when the resin film is cured, and is limited to solubility and compatibility with organic solvents during coating. It is very effective because it is never done. However, a material having extremely low solubility in the supercritical fluid and / or subcritical fluid or a material having a very large size such as a molecular structure is difficult to inject into the cured resin layer and may not be suitable.

Although an example of these additives is shown below, this invention is not limited to this.
Antioxidants are used mainly for the purpose of suppressing the effects of charge reduction caused by ozone gas or NOx gas generated by charging. Examples include the following.
(A) Phenolic compounds:
2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, n-octadecyl-3- (4′-hydroxy-3 ′, 5 '-Di-t-butylphenol), 2,2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-methylenebis (4-ethyl-6-t-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- (3 ' , 5'-Gee - butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3'-bis (4'-hydroxy-3'-t-butylphenyl) butyric acid] glycol ester, tocopherols, or the like.
(B) Paraphenylenediamines:
N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-s-butyl-p-phenylenediamine, N-phenyl-N-s-butyl-p-phenylenediamine, N, N'- Diisopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine and the like.
(C) 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.
(D) Organic sulfur compounds:
Dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate and the like.
(E) Organophosphorus compounds:
Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine and the like.

The plasticizer is used mainly for controlling the gas permeability of the photosensitive layer and improving the film quality. Examples include the following.
(A) Phosphate ester plasticizer:
Triphenyl phosphate, tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, trichloroethyl phosphate, cresyl diphenyl phosphate, tributyl phosphate, tri (2-ethylhexyl) phosphate, triphenyl phosphate and the like.
(B) Phthalate ester plasticizer:
Dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dibutyl phthalate, diheptyl phthalate, di (2-ethylhexyl) phthalate, diisooctyl phthalate, di-n-octyl phthalate, dinonyl phthalate, diisononyl phthalate, phthalate Diisodecyl acid, diundecyl phthalate, ditridecyl phthalate, dicyclohexyl phthalate, butyl benzyl phthalate, butyl lauryl phthalate, methyl oleyl phthalate, octyl decyl phthalate, dibutyl fumarate, dioctyl fumarate, etc.
(C) Aromatic carboxylic acid ester plasticizer:
Trioctyl trimellitic acid, tri-n-octyl trimellitic acid, octyl oxybenzoate and the like.
(D) Aliphatic dibasic ester plasticizer:
Dibutyl adipate, di-n-hexyl adipate, di (2-ethylhexyl) adipate, di-n-octyl adipate, n-octyl-n-decyl adipate, diisodecyl adipate, dicapryl adipate, diazeylate (2-ethylhexyl), dimethyl sebacate, diethyl sebacate, dibutyl sebacate, di-n-octyl sebacate, di (2-ethylhexyl) sebacate, di (2-ethoxyethyl) sebacate, dioctyl succinate, succinate Diisodecyl acid, dioctyl tetrahydrophthalate, di-n-octyl tetrahydrophthalate and the like.
(E) Fatty acid ester derivatives:
Butyl oleate, glycerin monooleate, methyl acetylricinoleate, pentaerythritol ester, dipentaerythritol hexaester, triacetin, tributyrin and the like.
(F) Oxyester plasticizer:
Methyl acetylricinoleate, butyl acetylricinoleate, butylphthalylbutyl glycolate, tributyl acetylcitrate and the like.
(G) Epoxy plasticizer:
Epoxidized soybean oil, epoxidized linseed oil, butyl epoxy stearate, decyl epoxy stearate, octyl epoxy stearate, benzyl epoxy stearate, dioctyl epoxy hexahydrophthalate, didecyl epoxy hexahydrophthalate and the like.
(H) Dihydric alcohol ester plasticizer:
Diethylene glycol dibenzoate, triethylene glycol di (2-ethylbutyrate), etc.
(I) Chlorine-containing plasticizer:
Chlorinated paraffin, chlorinated diphenyl, chlorinated fatty acid methyl, methoxychlorinated fatty acid methyl, etc.
(J) Polyester plasticizer:
Polypropylene adipate, polypropylene sebacate, polyester, acetylated polyester, etc.
(K) Sulfonic acid derivative:
p-toluenesulfonamide, o-toluenesulfonamide, p-toluenesulfoneethylamide, o-toluenesulfoneethylamide, toluenesulfone-N-ethylamide, p-toluenesulfone-N-cyclohexylamide and the like.
(L) Citric acid derivative:
Triethyl citrate, triethyl citrate, tributyl citrate, tributyl acetyl citrate, tri (2-ethylhexyl) citrate, n-octyldecyl acetyl citrate and the like.
(M) Other:
Terphenyl, partially hydrogenated terphenyl, camphor, 2-nitrodiphenyl, dinonylnaphthalene, methyl abietate and the like.

The main purpose of the lubricant is to increase the slipperiness of the surface of the photosensitive layer to prevent adhesion of foreign matters, to improve toner transferability, or to prevent blade squealing and turning. Examples include the following.
(A) Hydrocarbon compound:
Liquid paraffin, paraffin wax, microwax, low polymerized polyethylene, etc.
(B) Fatty acid compound:
Lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, etc.
(C) Fatty acid amide compound:
Stearylamide, palmitylamide, oleylamide, methylenebisstearylamide, ethylenebisstearoamide, etc.
(D) Ester compound:
Lower alcohol esters of fatty acids, polyhydric alcohol esters of fatty acids, fatty acid polyglycol esters, and the like.
(E) Alcohol compounds:
Cetyl alcohol, stearyl alcohol, ethylene glycol, polyethylene glycol, polyglycerol, etc.
(F) Metal soap:
Lead stearate, cadmium stearate, barium stearate, calcium stearate, zinc stearate, magnesium stearate and the like.
(G) Natural wax:
Carnauba wax, candelilla wax, beeswax, whale wax, ibota wax, montan wax, etc.
(H) Other:
Silicone compounds, fluorine compounds, etc.

Ultraviolet absorbers and light stabilizers are used mainly for the purpose of alleviating the influence of light applied to the photosensitive layer and preventing deterioration of electrostatic characteristics. Examples include the following.
(A) Benzophenone series:
2-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2,2 ′, 4-trihydroxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, and the like.
(B) Salsylate type:
Phenyl salicylate, 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, and the like.
(C) Benzotriazole series:
(2′-hydroxyphenyl) benzotriazole, (2′-hydroxy-5′-methylphenyl) benzotriazole, (2′-hydroxy-5′-methylphenyl) benzotriazole, (2′-hydroxy-3′-t) -Butyl-5'-methylphenyl) 5-chlorobenzotriazole and the like.
(D) Cyanoacrylate type:
2-cyano-3,3-diphenyl ethyl acrylate, methyl 2-carbomethoxy-3-p-methoxy acrylate and the like.
(E) Quencher (metal complex salt system):
Nickel (2,2′-thiobis (4-t-octyl) phenolate), nickel dibutyldithiocarbamate, nickel dibutyldithiocarbamate, cobalt dicyclohexyldithiophosphate and the like.
(F) HALS (hindered amine):
Bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2- [3- (3 5-di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6 6-tetramethylpyridine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4-dione, 4-benzoyloxy- 2,2,6,6-tetramethylpiperidine and the like.

<About the undercoat layer>
The photoreceptor of the present invention is effective because an undercoat layer can be provided between the conductive support and the photosensitive layer. As described above, when the anodizing treatment is not performed on the conductive support, formation of the undercoat layer is particularly effective.
The undercoat layer is mainly composed of a binder resin (binder resin), but these resins are resins having a high solvent resistance to general organic solvents, considering that a photosensitive layer is laminated thereon. It is desirable to be. Examples of such resins include water-soluble resins such as polyvinyl alcohol, polyvinyl butyral, casein, and sodium polyacrylate, alcohol-soluble resins such as polyamide, copolymer nylon, and methoxymethylated nylon, polyurethane, melamine resin, and alkyd-melamine resin. , Isocyanate resins, phenol resins, epoxy resins, and the like, and cross-linkable resins that form a three-dimensional network structure. Thermosetting resins are particularly preferable. Among these, alcohol-soluble resins are preferably used because they are excellent in suppressing charge injection from the substrate and have little influence on the residual potential. Among these, methoxymethylated nylon has a low electrostatic dependency on the environment and is used favorably. In the case where the undercoat layer is composed of only these resins, it does not have a function of transporting charges, so that it is necessary to reduce the film thickness. The thickness is preferably 2 μm or less, more preferably 1 μm or less, whereby charging reduction and background contamination can be suppressed, and the influence on the residual potential can be reduced.

  In addition, fillers such as metal oxides exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like can be added to the undercoat layer in order to prevent moire and reduce residual potential. ,It is valid. Among these, tin oxide, indium oxide and the like effective for reducing residual potential, preventing moire, and improving adhesiveness are preferably used. Moreover, these fillers can also be surface-treated and are used effectively. In addition, it is possible to add a charge transporting material contained in the photosensitive layer to the undercoat layer, and it may work well in terms of electrostatic characteristics. Although the film thickness of the undercoat layer mixed with the filler depends on the filler to be contained, it is preferably 1 to 20 μm, and more preferably 2 to 10 μm. It is also possible and effective to use two layers of the undercoat layer made of only the above-mentioned resin and the undercoat layer in which the filler is mixed.

  The coating liquid for forming the undercoat layer can be obtained by dispersing a metal oxide and a binder resin (binder resin) together with a solvent. As a dispersion method, any conventionally known method such as a ball mill, a sand mill, a bead mill, an ultrasonic wave, and a paint shaker can be used, and a ball mill is particularly preferable. As the solvent to be used, all common organic solvents can be used, but examples include methanol, ethanol, butanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl acetate, cyclohexane, toluene, xylene and the like. Among these, it is preferable to include acetone or methyl ethyl ketone, which are ketone solvents.

  As a method of applying the undercoat layer using the coating solution, known methods such as dip coating, spray coating, beat coating, nozzle coating, spinner coating, ring coating and the like can be used. The undercoat layer may be a single layer or two or more layers, but is preferably a single layer from the viewpoint of productivity and cost. After coating the undercoat layer, it is heated and dried in an oven or the like. Although the drying temperature of an undercoat layer changes with kinds of the solvent and thermosetting resin which are contained in the coating liquid of an undercoat layer, 80-180 degreeC is preferable and 100-150 degreeC is more preferable.

<About a manufacturing method of an electrophotographic photosensitive member>
The method for producing an electrophotographic photoreceptor of the present invention comprises a reactive compound (reactive monomer or oligomer, etc.) having no charge transporting structure on a conductive substrate and a reactive compound having a charge transporting structure as main components. A resin film forming step, a curing step in which the resin film thus formed is cured to form a cured resin layer, a charge generating material in the cured layer, and a hole transporting material and / or And a supercritical fluid treatment process in which a supercritical fluid and / or a subcritical fluid containing an electron transport material, an additive and the like are brought into contact with each other.
That is, a reactive monomer or oligomer having no charge transporting structure and a reactive compound having a charge transporting structure as a main component are provided on a conductive support (if necessary, an undercoat layer is provided thereon). A supercritical fluid containing a charge generating substance, a charge transporting substance, and the like after coating and forming with a coating liquid, curing the formed film to form a cured resin layer having a three-dimensional network structure And / or injecting in contact with a subcritical fluid.
As a method of coating a layer mainly composed of a reactive monomer or oligomer having no charge transport structure and a reactive compound having a charge transport structure on a conductive support, a conventionally known method may be used. Is possible. Examples include dip coating, spray coating, beat coating, nozzle coating, spinner coating, ring coating, and the like, and dip coating and spray coating are particularly preferable.

The coating liquid for forming a layer mainly composed of a reactive monomer or oligomer having no charge transporting structure and a reactive compound having a charge transporting structure is the reactive monomer or curing necessary for the curing reaction. And an additive such as a catalyst, a polymerization initiator and a leveling agent, and an organic solvent as necessary.
The organic solvent can be appropriately selected in accordance with the solubility of the material, the viscosity of the coating liquid, and the solid content, and examples include generally used solvents. Examples 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, ethers such as tetrahydrofuran, dioxane and propyl ether, Examples include 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. May be.

  In addition, when cured, it may become brittle or the crosslinking density is too high, which may cause deterioration of the film quality.If necessary, prepare a coating solution by mixing thermoplastic resin in advance. It is also possible to provide. If an excessive amount of thermoplastic resin is added, curing is inhibited, which is not preferable, but an appropriate amount may be effective. Examples of such thermoplastic resins include polycarbonate, polyarylate, polystyrene, polyester and the like.

The resin film formed by coating is sufficiently cured by applying energy from the outside. Examples of such external energy include heat, light, and radiation.
Examples of a method of applying heat energy include a method of heating from the coating surface side or the support side using a gas such as air and nitrogen, steam, various heat media, infrared rays, and electromagnetic waves. In the case of thermosetting, the heating temperature is preferably 80 ° C. or higher and 200 ° C. or lower, more preferably 100 ° C. or higher and 160 ° C. or lower, although it depends on the solvent used, the presence or absence of a catalyst, and the like. If the temperature is too low, the reaction rate is slow and the curing reaction may not be completed completely. On the other hand, if the temperature is too high, the curing reaction may proceed non-uniformly, or large strains, a large number of unreacted residues, and reaction termination ends may occur in the layer. In order to advance the curing reaction uniformly, a method of heating at a relatively low temperature of less than 100 ° C. and then heating to 100 ° C. or more to complete the reaction is also preferable.

Examples of the energy of light include UV irradiation light sources such as high-pressure mercury lamps and metal halide lamps having an emission wavelength in the ultraviolet region, but the visible light source can be used in accordance with the absorption wavelength of radical polymerizable substances and photopolymerization initiators. Selection is also possible. A suitable amount of irradiation is 50 to 1000 mW / cm ² . If it is less than 50 mW / cm ² , the curing reaction may take time.
On the other hand, by using intense irradiation light of 1000 mW / cm ² or more, the progress speed of the polymerization reaction can be greatly increased, and a more uniform cured layer can be formed. In some cases, a general flaw occurs, or a large number of unreacted residues or reaction termination ends occur. It is more preferable to control the drum temperature so as not to exceed 50 ° C.

Examples of radiation energy include those using electron beams or γ rays.
In the case of electron beam irradiation, any type of accelerator such as a scanning type, an electro curtain type, a broad beam type, a pulse type, and a laminar type can be used.
The greatest advantage of radiation polymerization is that it does not require a polymerization initiator, which makes it possible to produce a very high-purity three-dimensional photosensitive layer matrix and ensure good electrophotographic properties. . In addition, because it is a short and efficient polymerization reaction, the productivity is also high, and furthermore, because of its good radiation transmission, it inhibits curing when a thick film or additives such as additives are present in the film. The influence of the is very small. However, depending on the type of the chain polymerizable group and the type of the central skeleton, the polymerization reaction may not easily proceed, and in this case, the polymerization initiator can be added within a range that does not affect the polymerization reaction. As irradiation conditions when irradiating with an electron beam, the acceleration voltage is preferably 250 KV or less, and optimally 150 KV or less. The absorbed dose of the electron beam is preferably 1 × 10 ³ to 1 × 10 ⁶ Gy, more preferably 5 × 10 ^{3 to} 5 × 10 ⁵ Gy. If the absorbed dose is less than 1 × 10 ³ Gy, it is difficult to sufficiently cure the surface layer, and if it exceeds 1 × 10 ⁶ Gy, sensitivity and residual potential characteristics are liable to be deteriorated.

  The thickness of the cured resin layer, that is, the photosensitive layer is preferably 5 to 35 μm, and more preferably 10 to 25 μm. Since the photoreceptor of the present invention has a single photosensitive layer, even if the film thickness is large, the influence on the image quality is small, but it is expected that there is some influence on the uniformity of the curing reaction. Moreover, when the film thickness becomes thicker than necessary, there is a concern that the film may be peeled off. On the other hand, if the film thickness is too thin, charging and sensitivity may be reduced.

<About image forming apparatus>
Next, the image forming apparatus of the present invention will be described in detail with reference to the drawings.
FIG. 3 is a schematic diagram for explaining the electrophotographic process and the image forming apparatus of the present invention, and the following examples also belong to the category of the present invention. In FIG. 3, a photoconductor (21) is a photoconductor having the structure described in FIGS.
The photoreceptor (21) has a drum shape, but may be a sheet or an endless belt. The photosensitive member (21) includes a charging step by the charging member (23), an exposure step by the exposure unit (24), a development step by the development unit (25), a transfer step by the transfer unit (29), and a cleaning unit (33) (34). The image is formed on the transfer paper (28) and the like through the cleaning process by (1) and the charge removing process by the charge removal lamp (22). In addition, a pre-transfer charger (26), a separation charger (30), a separation claw (31), a pre-cleaning charger (32), and the like are provided as necessary. However, the present invention is not limited to this, and all known means can be used.

  As the charging member, a non-contact charging method such as corona charging or a contact charging method using a roller or a brush is generally used, and any of them can be used effectively in the present invention. In particular, the charging roller can significantly reduce the amount of ozone generated compared to corotron, scorotron, etc., and is effective in stability and prevention of image quality deterioration when the photoreceptor is used repeatedly. However, due to the contact between the photoconductor and the charging roller, the charging roller is contaminated by repeated use, which affects the photoconductor and contributes to the occurrence of abnormal images and reduced wear resistance. It was. In particular, when the photoconductor having high wear resistance according to the present invention is used, it is difficult to perform reface due to surface wear, and therefore it is necessary to reduce the contamination of the charging roller.

  Therefore, as shown in FIG. 4, the charging roller (23) is disposed close to the photosensitive member (21) via a gap, so that contaminants are less likely to adhere to the charging roller (23) or are easily removed. These effects can be reduced, and the present invention can also be used effectively. In this case, the gap between the photoconductor (21) and the charging roller (23) is preferably small, and is 100 μm or less, more preferably 50 μm or less. However, by making the charging roller (23) non-contact, the discharge becomes non-uniform and the photosensitive member (21) may be unstablely charged. In the present invention, it is possible to maintain the charging stability by superimposing the AC component on the DC component, thereby simultaneously reducing the influence of ozone, the contamination of the charging charger (23), and the charging effect. Thus, by using in combination with the photoconductor (21) having high wear resistance, further high durability and high image quality are realized.

  The light source such as the image exposure unit (24) and the charge removal lamp (22) shown in FIG. 3 includes a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and electroluminescence. All luminescent materials such as (EL) can be used. Among these, a semiconductor laser (LD) and a light emitting diode (LED) are mainly 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.

  In addition to the steps shown in FIG. 3, the light source or the like is provided with a transfer step, a static elimination step, a cleaning step, or a pre-exposure step that uses light irradiation, so that the photosensitive member is irradiated with light. However, the exposure of the photoconductor in the static elimination step has a great influence of fatigue on the photoconductor, and may cause a decrease in charge and an increase in residual potential. Therefore, it may be possible to eliminate static electricity by applying a reverse bias in the charging process or cleaning process, instead of static elimination by exposure, which may be effective from the viewpoint of enhancing the durability of the photoreceptor.

  When the electrophotographic 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. A known method is applied to the developing unit, and a known method is also used for the charge eliminating unit.

  As the transfer means, the above-described charger can be generally used, but a combination of the transfer charger (29) and the separation charger (30) is effective as shown in FIG. Further, the toner image is directly transferred from the photosensitive member to the paper using such a transfer unit. In the present invention, the toner image on the photosensitive member is once transferred to the intermediate transfer member, and then from the intermediate transfer member to the paper. The intermediate transfer method for transferring the toner to the photosensitive member is more preferable for improving the durability or image quality of the photoreceptor.

  The intermediate transfer method is particularly effective for image forming apparatuses capable of full-color printing, and controls the prevention of color misregistration by forming a plurality of toner images on the intermediate transfer member and then transferring them to the paper at once. It is easy and effective for high image quality. The intermediate transfer member includes various materials or shapes such as a drum shape and a belt shape. In the present invention, any conventionally known intermediate transfer member can be used and is effective and useful. .

  The toner developed on the photosensitive member (21) by the developing unit (25) is transferred to the transfer paper (28), but not all is transferred, and the toner remaining on the photosensitive member (21) is also transferred. Arise. Such toner is removed from the photoreceptor by a fur brush (33) or a blade (34). This cleaning process may be performed only with a cleaning brush or may be performed in combination with a blade, and known cleaning brushes such as a fur brush and a mag fur brush are used.

  As described above, the cleaning is a process of removing toner remaining on the photoconductor after transfer. However, the photoconductor is repeatedly rubbed by the above-described blade or brush, so that the photoconductor is worn or damaged. An abnormal image may occur by entering. In addition, if the surface of the photoconductor is contaminated due to poor cleaning, it not only causes an abnormal image, but also significantly reduces the life of the photoconductor. In particular, in the case of a photoreceptor having a layer containing a pigment for improving abrasion resistance on the outermost surface, contaminants attached to the surface of the photoreceptor are difficult to remove. It will promote the occurrence of. Therefore, improving the cleaning property of the photoconductor is very effective for improving the durability and image quality of the photoconductor.

  As means for improving the cleaning property of the photosensitive member, a method of reducing the coefficient of friction on the surface of the photosensitive member is known. Methods for reducing the coefficient of friction on the surface of the photoreceptor are classified into a method in which various lubricants are contained in the photoreceptor surface and a method in which the lubricant is supplied to the photoreceptor surface from the outside. The former is advantageous for small-diameter photoreceptors because of the high degree of freedom in layout around the engine, but the coefficient of friction increases remarkably with repeated use, and there remains a problem in its sustainability. On the other hand, the latter needs to be provided with a component for supplying a lubricating substance, but is effective for enhancing the durability of the photoreceptor because of high stability of the friction coefficient. Among them, the method of adhering to the photoreceptor during development by incorporating a lubricant into the developer is not restricted by the layout around the engine, and the effect of reducing the friction coefficient on the photoreceptor surface is high. Therefore, it is an effective means for improving the durability and image quality of the photoreceptor.

  These lubricants include lubricating fluids such as silicone oil and fluorine oil, various fluorine-containing resins such as PTFE, PFA and PVDF, silicone resins, polyolefin resins, silicone grease, fluorine grease, paraffin wax, fatty acid esters , Fatty acid metal salts such as zinc stearate, lubricating liquids such as graphite and molybdenum disulfide, solids, powders, and the like, but particularly when mixed with a developer, it must be in the form of a powder, especially stearic acid Zinc has little adverse effect and can be used very effectively. When the zinc stearate powder is contained in the toner, it is necessary to consider the balance and influence on the toner, and the content is preferably 0.01 to 0.5% by weight with respect to the toner, preferably 0.1 to 0.3%. 3% by weight is more preferred.

  The photoconductor of the present invention is for a so-called tandem image forming apparatus that includes a plurality of photoconductors corresponding to each developing unit corresponding to a plurality of color toners and performs parallel processing thereby. Even effectively used. The tandem image forming apparatus includes at least four color toners of yellow (C), magenta (M), cyan (C), and black (K) required for full-color printing and a developing unit that holds them. Furthermore, by providing at least four photoconductors corresponding to them, it is possible to perform full-color printing at an extremely high speed as compared with a conventional image forming apparatus capable of full-color printing.

  FIG. 5 is a schematic view for explaining the tandem-type full-color electrophotographic apparatus of the present invention, and the following modifications also belong to the category of the present invention. In FIG. 5, reference numerals (1C, 1M, 1Y, 1K) denote drum-shaped photoconductors, which are photoconductors of the present invention. The photoreceptors (1C, 1M, 1Y, 1K) rotate in the direction of the arrow in the figure, and at least around them are charged members (2C, 2M, 2Y, 2K) and developing members (4C, 4M, 4Y, 4K). ), Cleaning members (5C, 5M, 5Y, 5K) are arranged. The charging members (2C, 2M, 2Y, 2K) are charging members that constitute a charging device for uniformly charging the surface of the photoreceptor.

  Laser light (3C, 3M, 3Y, 3K) from an exposure member (not shown) from the photosensitive member surface side between the charging member (2C, 2M, 2Y, 2K) and the developing member (4C, 4M, 4Y, 4K) , And an electrostatic latent image is formed on the photoreceptor (1C, 1M, 1Y, 1K). Then, four image forming elements (6C, 6M, 6Y, 6K) centering on such a photoreceptor (1C, 1M, 1Y, 1K) are along a transfer conveyance belt (10) which is a transfer material conveyance means. Are juxtaposed. The transfer / conveying belt (10) is provided between the developing member (4C, 4M, 4Y, 4K) and the cleaning member (5C, 5M, 5Y, 5K) of each image forming unit (6C, 6M, 6Y, 6K). 1C, 1M, 1Y, 1K), and a transfer brush (11C, 11M, 11Y, 11K) for applying a transfer bias to the back surface (back surface) of the transfer conveyance belt (10) that contacts the back side of the photoconductor. Is arranged. Each image forming element (6C, 6M, 6Y, 6K) is different in the color of the toner inside the developing device, and the others are the same in configuration.

  In the color image forming apparatus having the configuration shown in FIG. 5, the image forming operation is performed as follows. First, in each image forming element (6C, 6M, 6Y, 6K), the charging member (2C, 2M, 2Y) in which the photoconductor (1C, 1M, 1Y, 1K) rotates in the direction of the arrow (direction along with the photoconductor). , 2K), and then an electrostatic latent image corresponding to each color image to be created by laser light (3C, 3M, 3Y, 3K) by an exposure unit (not shown) disposed outside the photoconductor. It is formed.

  Next, the latent image is developed by the developing members (4C, 4M, 4Y, 4K) to form a toner image. The developing members (4C, 4M, 4Y, 4K) are developing members that perform development with toners of C (cyan), M (magenta), Y (yellow), and K (black), respectively. 1M, 1Y, and 1K) are overlaid on the transfer paper. The transfer paper (7) is fed out from the tray by the paper feed roller (8), temporarily stopped by the pair of registration rollers (9), and then transferred to the transfer conveyance belt (10) in synchronization with the image formation on the photosensitive member. Sent. The transfer paper (7) held on the transfer / conveying belt (10) is conveyed, and the toner images of the respective colors are transferred at the contact positions (transfer portions) with the respective photoreceptors (1C, 1M, 1Y, 1K). It is.

  The toner image on the photosensitive member is transferred onto the transfer paper (by the electric field formed by the potential difference between the transfer bias applied to the transfer brush (11C, 11M, 11Y, 11K) and the photosensitive member (1C, 1M, 1Y, 1K). 7) Transferred on top. Then, the recording paper (7) on which the toner images of four colors are superimposed through the four transfer portions is conveyed to the fixing device (12), where the toner is fixed, and is discharged to a paper discharge portion (not shown). Further, the residual toner remaining on the respective photoconductors (1C, 1M, 1Y, 1K) without being transferred by the transfer unit is collected by the cleaning device (5C, 5M, 5Y, 5K).

  In the example of FIG. 5, the image forming elements are arranged in the order of C (cyan), M (magenta), Y (yellow), and K (black) from the upstream side to the downstream side in the transfer sheet conveyance direction. However, it is not limited to this order, and the color order is arbitrarily set. Further, when a black-only document is created, it is particularly effective to use the present invention to provide a mechanism for stopping the image forming elements (6C, 6M, 6Y) other than black. Further, although the charging member is in contact with the photosensitive member in FIG. 5, by using a charging mechanism as shown in FIG. 4, an appropriate gap (about 10 to 200 μm) is provided between the two. In addition, the wear amount of the both can be reduced, and toner filming on the charging member can be reduced and the toner can be used satisfactorily.

  The above-described tandem image forming apparatus can transfer a plurality of toner images at a time, so that high-speed full-color printing is realized. However, since at least four photoconductors are required, an increase in the size of the apparatus is unavoidable, and depending on the amount of toner used, there is a difference in the wear amount of each photoconductor, thereby reproducing the color. There are many problems such as a decrease in performance and occurrence of abnormal images. On the other hand, the photoconductor according to the present invention has high wear resistance by forming a protective layer, so that it can be applied even to a small-diameter photoconductor, and the influence of increase in residual potential and sensitivity deterioration is reduced. Even if the usage amounts of the four photoconductors are different, the difference in residual potential and sensitivity over time is small, and it is possible to obtain a full color image with excellent color reproducibility even when used repeatedly for a long time.

The above illustrated electrophotographic process exemplifies an embodiment of the present invention, and of course, other embodiments are possible.
The image forming means as described above may be fixedly incorporated in a copying apparatus, a facsimile, or a printer, but may be incorporated in these apparatuses in the form of a process cartridge. A process cartridge is a single device (part) that contains a photosensitive member and includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit. There are many shapes and the like of the process cartridge, but a general example is shown in FIG.
Here, the process cartridge incorporates a photoreceptor [drum] (101), charging means [contact charging device] (102), exposure means [image exposure] (103), developing means [developing device] (104). And a cleaning means (cleaning unit) (107), and further include other means as required. In the figure, reference numeral 105 denotes a recording medium [transfer body], and 106 denotes a transfer means [contact transfer apparatus]. The photoconductor [drum] (101) is the photoconductor shown in FIG.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not restrict | limited by an Example. All parts are parts by weight.
First, synthesis examples of the compound having a charge transporting structure used in the present invention are shown. The compound having a charge transporting structure in the present invention is synthesized, for example, by the method described in Japanese Patent No. 3164426. An example of this is shown below.

<Synthesis Example of Compound having Charge Transporting Structure>
(1) Synthesis of hydroxy group-substituted triarylamine compound:
240 ml of sulfolane was added to 113.85 g (0.3 mol) of a methoxy group-substituted triarylamine compound [the following structural formula (A)] and 138 g (0.92 mol) of sodium iodide, and the mixture was heated to 60 ° C. in a nitrogen stream. . In this liquid, 99 g (0.91 mol) of trimethylchlorosilane was added dropwise over 1 hour and stirred at a temperature of about 60 ° C. for 4 and a half hours to complete the reaction. About 1.5 L of toluene was added to the reaction solution, cooled to room temperature, and washed repeatedly with water and an aqueous sodium carbonate solution. Thereafter, the solvent was removed from the toluene solution, and purification was performed by column chromatography (adsorption medium: silica gel, developing solvent: toluene: ethyl acetate = 20: 1). Cyclohexane was added to the obtained pale yellow oil to precipitate crystals.
As a result, 88.1 g (yield = 80.4%) of white crystals of a hydroxy group-substituted triarylamine compound represented by the following structural formula (B) was obtained. The melting point of the obtained compound was 64.0 to 66.0 ° C., and the elemental analysis results were in good agreement with the calculated values as shown in Table 5 below.

(2) Triarylamino group-substituted acrylate compound (Exemplary Compound No. 54):
82.9 g (0.227 mol) of the hydroxy group-substituted triarylamine compound [Structural Formula (B)] obtained in the above (1) is dissolved in 400 ml of tetrahydrofuran, and an aqueous sodium hydroxide solution (NaOH: 12.2. 4 g, water: 100 ml) was added dropwise. The solution was cooled to 5 ° C., and 25.2 g (0.272 mol) of acrylic acid chloride was added dropwise over 40 minutes. Then, it stirred at 5 degreeC for 3 hours, and reaction was complete | finished. The reaction solution was poured into water and extracted with toluene. This extract was repeatedly washed with an aqueous sodium bicarbonate solution and water. Thereafter, the solvent was removed from the toluene solution, and purification was performed by column chromatography (adsorption medium: silica gel, developing solvent: toluene). N-Hexane was added to the obtained colorless oil to precipitate crystals. In this way, 80.73 g (yield = 84.8%) of white crystals of a triarylamino group-substituted acrylate compound (Exemplary Compound No. 54) was obtained. The melting point of the obtained compound was 117.5 to 119.0 ° C., and the elemental analysis results were in good agreement with the calculated values as shown in Table 6 below.

Example 1
An undercoat layer coating solution having the following composition was applied onto an aluminum tube having an outer diameter of 30 mm, followed by heat drying at 130 ° C. for 10 minutes to form an undercoat layer of about 0.5 μm.

[Coating liquid for undercoat layer]
・ N-methoxymethylated nylon: FR101K (Lead City Co., Ltd.)
Solvent: methanol / n-butanol <mixing conditions (parts)>
N-methoxymethylated nylon / methanol / n-butanol = 5/70/30

On the undercoat layer, after coating using a coating resin for a cured resin layer having the following composition, curing was performed under heating conditions at 150 ° C. for 40 minutes to form a cured resin layer of about 18 μm.
[Coating liquid for cured resin layer]
・ Isocyanate: Sumijoule HT (HDI adduct) (manufactured by Sumika Bayern)
Polyol 1: Structural formula (C) below

・ポリオール２：ＬＺＲ１７０（藤倉化成社製）
・電荷輸送性構造を有する反応性化合物：下記構造式（Ｄ）

Polyol 2: LZR170 (manufactured by Fujikura Kasei Co., Ltd.)
Reactive compound having a charge transporting structure: Structural formula (D)

・溶剤：テトラヒドロフラン／シクロヘキサノン
〈混合条件（部）〉
イソシアネート／ポリオール１／ポリオール２／電荷輸送性構造を有する反応性化合物／テトラヒドロフラン／シクロヘキサノン＝３／２／８／１０／１００／３０

・ Solvent: Tetrahydrofuran / Cyclohexanone <Mixing conditions (parts)>
Isocyanate / polyol 1 / polyol 2 / reactive compound having a charge transporting structure / tetrahydrofuran / cyclohexanone = 3/2/8/10/100/30

<Injection treatment with supercritical fluid>
Next, an aluminum tube having the cured resin layer formed thereon, 0.1 part of a charge generation material represented by the following structural formula (E), 1.5 parts of an electron transport material represented by the ETM7, and the following structural formula (F ) Was added to the pressure-resistant reaction cell shown in FIG. 7, and all valves were closed. Thereafter, the valve 1 (V1) and the valve 3 (V3) are opened, the carbon dioxide is supplied from the supply cylinder to the pressure-resistant reaction cell while controlling the pressure with the back pressure valve, and the temperature regulator using the pressure pump 1 and the temperature control jacket Thus, while expanding the pressure-resistant reaction cell, the temperature and pressure were adjusted to 85 ° C. and 30 MPa over about 20 minutes, and after the temperature and pressure were stabilized, the temperature and pressure were maintained for 2 hours. Thereafter, the temperature and pressure in the pressure-resistant reaction cell are gradually lowered and reduced in pressure over about 20 minutes until the temperature and pressure are controlled by the temperature control jacket and the back pressure valve until it reaches 25 ° C. and atmospheric pressure. The body was made. In addition, the code | symbol (V1)-(V3) in a figure represents the valve | bulb 1-the valve | bulb 3, (T) shows a temperature sensor, (P) shows a pressure sensor.

(Example 2)
An electrophotographic photoreceptor of the present invention was produced in the same manner as in Example 1 except that the reactive compound having a charge transporting structure in Example 1 was changed to the compound of the following structural formula (G).

(Example 3)
An electrophotographic photosensitive member of the present invention was produced in the same manner as in Example 1 except that the reactive compound having a charge transporting structure in Example 1 was changed to the compound of the following structural formula (H).

Example 4
An electrophotographic photosensitive member of the present invention was produced in the same manner as in Example 1 except that the electron transport material was changed to ETM4 in Example 1.

(Example 5)
An electrophotographic photosensitive member of the present invention was produced in the same manner as in Example 1 except that the charge generation material was changed to X-type metal-free phthalocyanine in Example 1.

(Example 6)
In Example 1, an electrophotographic photoreceptor of the present invention was produced in the same manner as Example 1 except that 0.3 part of HTM4 was added during the supercritical fluid injection process.

(Example 7)
In Example 1, the electrophotographic film of the present invention was used in the same manner as in Example 1 except that the coating liquid for the cured resin layer was changed to the following composition, coating was performed, and then curing was performed under the following curing conditions. A photoconductor was prepared.
[Coating liquid for cured resin layer]
Trimethylolpropane triacrylate: KAYARAD TMPTA (molecular weight: 296, functional group number: trifunctional, molecular weight / functional group number = 99) (manufactured by Nippon Kayaku)
Reactive compounds having a charge transport structure: Exemplified Compound No. 54
Photopolymerization initiator: 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
・ Tetrahydrofuran <Mixing conditions (parts)>
Trimethylolpropane triacrylate / reactive compound having a charge transporting structure / photopolymerization initiator / tetrahydrofuran = 10/10/1/100
<Curing method>
Using a metal halide lamp, light irradiation was performed under the conditions of an irradiation intensity of 400 mW / cm ² and an irradiation time of 120 seconds, and further heat drying at 130 ° C. for 20 minutes.

(Example 8)
In Example 7, 9 parts of a reactive compound (Exemplary Compound No. 54) having a charge transporting structure contained in the cured resin layer coating solution and 1 part of a bifunctional compound of the following structural formula (I) Except for this, the electrophotographic photoreceptor of the present invention was produced in the same manner as in Example 7.
Reactive compound having a monofunctional charge transport structure: Exemplified Compound No. 54
Reactive compound having a bifunctional charge transport structure: Structural formula (I)

〈混合条件（部）〉
１官能の電荷輸送性構造を有する反応性化合物／２官能の電荷輸送性構造を有する反応性化合物＝９／１

<Mixing conditions (parts)>
Reactive compound having monofunctional charge transport structure / Reactive compound having bifunctional charge transport structure = 9/1

Example 9
In Example 7, the electrophotographic photosensitive member of the present invention was produced in the same manner as in Example 7 except that the electron transport material was changed to ETM8.

(Example 10)
In Example 7, the electron of the present invention was used in the same manner as in Example 7 except that the light stabilizer of the following structural formula (J) was added to the cured resin layer coating solution without adding an antioxidant. A photographic photoreceptor was prepared.

（実施例１１）
実施例１において、酸化防止剤を含有させなかった以外は、すべて実施例１と同様にして本発明の電子写真感光体を作製した。

(Example 11)
In Example 1, an electrophotographic photosensitive member of the present invention was produced in the same manner as in Example 1 except that the antioxidant was not included.

Example 12
In Example 1, the electrophotographic photosensitive member of the present invention was produced in the same manner as in Example 1 except that the cured resin layer was formed without forming the undercoat layer on the conductive support.

(Comparative Example 1)
In Example 1, the cured resin layer coating solution was changed to the following photosensitive layer forming coating solution and applied, followed by heating and drying at 135 ° C. for 20 minutes to form a photosensitive layer of about 18 μm. A photographic photoreceptor was prepared. The injection process with supercritical fluid was not performed.
[Photosensitive layer forming coating solution]
-Charge generation material: Structural formula (E) below

・ホール輸送物質：ＨＴＭ４
・電子輸送物質：ＥＴＭ７
・Ｚ型ポリカーボネート：ＴＳ−２０４０（帝人化成社製）
・シリコーンオイル：ＫＦ５０（信越化学工業社製）
・テトラヒドロフラン
〈混合条件（部）〉
電荷発生物質／ホール輸送物質／電子輸送物質／ポリカーボネート／シリコーンオイル／テトラヒドロフラン＝２／２５／２５／５０／０．０１／４００

-Hole transport material: HTM4
-Electron transport material: ETM7
・ Z-type polycarbonate: TS-2040 (manufactured by Teijin Chemicals Ltd.)
・ Silicone oil: KF50 (manufactured by Shin-Etsu Chemical Co., Ltd.)
・ Tetrahydrofuran <Mixing conditions (parts)>
Charge generation material / hole transport material / electron transport material / polycarbonate / silicone oil / tetrahydrofuran = 2/25/25/50 / 0.01 / 400

(Comparative Example 2)
An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 1 except that the thickness of the photosensitive layer was changed to 27 μm in Comparative Example 1.

(Comparative Example 3)
In Example 1, an electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the injection process using the supercritical fluid was not performed.

(Comparative Example 4)
In Example 7, an electrophotographic photosensitive member was produced in the same manner as in Example 7 except that the coating liquid for the cured resin layer was changed to the following composition and the treatment with the supercritical fluid was not performed.
[Curing layer coating liquid]
Trimethylolpropane triacrylate: KAYARAD TMPTA (molecular weight: 296, functional group number: trifunctional, molecular weight / functional group number = 99) (manufactured by Nippon Kayaku)
Photopolymerization initiator: 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
-Charge generation material: Structural formula (E) below

・ホール輸送物質：ＨＴＭ４
・電子輸送物質：ＥＴＭ７
・テトラヒドロフラン
〈混合条件（部）〉
トリメチロールプロパントリアクリレート／光重合開始剤／電荷発生物質／ホール輸送物質／電子輸送物質／テトラヒドロフラン＝２０／１／１／１０／１０／１００

-Hole transport material: HTM4
-Electron transport material: ETM7
・ Tetrahydrofuran <Mixing conditions (parts)>
Trimethylolpropane triacrylate / photopolymerization initiator / charge generating material / hole transport material / electron transport material / tetrahydrofuran = 20/1/1/10/10/100

(Comparative Example 5)
After applying the undercoat layer on the aluminum tube having an outer diameter of 30 mm using the undercoat layer coating solution shown below, heat drying at 130 ° C. for 10 minutes to form an undercoat layer of about 0.5 μm did.
[Coating liquid for undercoat layer]
・ N-methoxymethylated nylon: FR101K (Lead City Co., Ltd.)
Solvent: methanol / n-butanol <mixing conditions (parts)>
N-methoxymethylated nylon / methanol / n-butanol = 5/70/30

Subsequently, the charge generation layer was applied using a charge generation layer coating solution having the following composition, followed by heating and drying at 130 ° C. for 20 minutes to form a charge generation layer of about 0.2 μm.
[Coating liquid for charge generation layer]
Charge generation material: Structural formula (E) below

・ポリビニルブチラール：ＸＹＨＬ（ＵＣＣ社製）
・２−ブタノン
・シクロヘキサノン
〈混合条件（部）〉
電荷発生物質／ポリビニルブチラール／２−ブタノン／シクロヘキサノン＝４／１／１２０／５０

-Polyvinyl butyral: XYHL (UCC)
・ 2-butanone ・ Cyclohexanone <Mixing conditions (parts)>
Charge generation material / polyvinyl butyral / 2-butanone / cyclohexanone = 4/1/120/50

Subsequently, after applying the charge transport layer using the coating liquid for charge transport layer having the following composition, heating and drying at 130 ° C. for 20 minutes to form a charge transport layer of about 20 μm to prepare an electrophotographic photosensitive member. .
[Coating fluid for charge transport layer]
Charge transport material: HTM4
・ Z-type polycarbonate: TS-2040 (manufactured by Teijin Chemicals Ltd.)
Tetrahydrofuran Silicone oil: KF50 (manufactured by Shin-Etsu Chemical Co., Ltd.)
<Mixing conditions (parts)>
Charge transport material / polycarbonate / tetrahydrofuran / silicone oil = 4/5/40 / 0.001

(Comparative Example 6)
In Comparative Example 5, a protective layer was further coated on the charge transport layer using a protective layer coating liquid having the following composition, and then cured under the following curing conditions to form a protective layer of about 3 μm. Except for the above, an electrophotographic photosensitive member was produced in the same manner as in Comparative Example 5.
[Coating liquid for protective layer]
Trimethylolpropane triacrylate: KAYARAD TMPTA (molecular weight: 296, functional group number: trifunctional, molecular weight / functional group number = 99) (manufactured by Nippon Kayaku)
Photopolymerization initiator: 1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)
Reactive compounds having a charge transporting structure: Exemplified Compound No. 54
-Electron transport material: ETM7
・ Tetrahydrofuran <Mixing conditions (parts)>
Acrylate / polymerization initiator / reactive compound having charge transport structure / electron transport material / tetrahydrofuran = 10/1/4/4/70
<Curing method>
Using a metal halide lamp, light irradiation was performed under the conditions of irradiation intensity of 400 mW / cm ² and irradiation time of 120 seconds, and further heat drying at 130 ° C. for 20 minutes.

〔An endurance test〕
The photoconductors of Examples and Comparative Examples produced as described above are mounted on an electrophotographic process cartridge as shown in the schematic diagram of FIG. 6, and a modified machine for the image forming apparatus as shown in the schematic diagram of FIG. Mounted on. A scorotron was used as the charging means, and the applied voltage was set so that the charged potential of the photosensitive member at the start of the test was + 550V. A 655 nm semiconductor laser was provided as the image exposure light source, and the amount of exposure light was adjusted each time so that the light attenuation characteristics of the photoconductor became substantially constant. The developing unit was filled with positive charging toner, and the developing bias was set to + 400V. A cleaning blade was used as the cleaning means, and a 655 nm LED was used as the static elimination means.
An endurance test was conducted in an environment of 25 ° C. and 50% RH using the above apparatus.
At the start of the test (initial stage) and at the end of the test (after printing 40,000 sheets), the exposure portion potential (VL) was measured and the image quality of the output image samples was evaluated. The level of image evaluation was expressed in the following four stages.
A: Very good level B: Slight image quality degradation but no problem Δ: Level where image defects are clearly recognized ×: Image defect is greatly affected and image quality is very bad.
These evaluation results are shown in Table 7 below.

[Accelerated deterioration test]
The photosensitive member was subjected to ozone exposure and image evaluation was performed in the same manner as described above. For exposure to ozone, the photoconductor was placed in an ozone exposure device, sealed, exposed at an ozone gas concentration of 5 ppm for 48 hours, and stored in the dark atmosphere for 3 hours before image evaluation.
A: Very good level B: Slight image quality degradation but no problem Δ: Level where image defects are clearly recognized ×: Image defect is greatly affected and image quality is very bad.
These results are shown in Table 8 below.

As is clear from the evaluation results in Table 7 above, the photoreceptor of the present invention has a sufficiently low exposed area potential, excellent electrostatic characteristics, and almost no increase in exposed area potential even after repeated use. High stabilization of electrostatic characteristics was realized. In addition, the image quality is very good with high definition, and the image quality was maintained even after repeated use. Furthermore, since the photosensitive layer is composed of a cured resin layer, the amount of wear due to repeated use is very small, and image quality deterioration with time was hardly observed. Further, from the evaluation results in Table 8, it was confirmed that in the accelerated deterioration test by ozone exposure, the image quality was slightly lowered when the antioxidant was not included, but at other levels, there was no problem in image quality.
On the other hand, a conventionally known photoreceptor as a comparative example has low wear resistance in a single-layer photoreceptor, and the influence of scumming increases due to an increase in electric field strength due to wear. When a curable binder resin and a charge generation material or charge transport material are contained and cured, the wear resistance is impaired due to the inhibition of curing, and the residual amount of unreacted monomer is remarkably increased. Electrical characteristics also deteriorated. In addition, in the laminated type photoreceptor in which a plurality of photosensitive layers are laminated, the layer interface that induces charge trapping is increased, the exposed portion potential is increased, and the abrasion resistance is low. Forming a cured protective layer on the charge transport material to increase wear resistance improved the wear resistance, but increased layer interface induced charge trapping, and when a halftone image was output, An image defect called a ghost or an afterimage, in which a previously formed image is formed, causes a reduction in image quality.

  As is clear from the above results, the photoconductor of the present invention can output a higher definition image than the multi-layer photoconductor, is excellent in wear resistance, has good electrostatic characteristics, and can be used repeatedly. By using a supercritical fluid and / or a subcritical fluid, a highly durable photoconductor that can stably maintain the effect can be realized. Furthermore, the present invention is capable of improving productivity, reducing production cost, and reducing the burden on the global environment. An extremely excellent method for producing a photoconductor, which has never been obtained before, and a photoconductor obtained thereby, and The used image forming apparatus and process cartridge were provided.

1 is a schematic cross-sectional view showing an example of an electrophotographic photoreceptor in the present invention [configuration in which a photosensitive layer (2) is formed on a conductive support (1)]. FIG. 2 is a schematic cross-sectional view showing another example of an electrophotographic photosensitive member in which an undercoat layer [or intermediate layer] (3) is formed between the conductive support and the photosensitive layer of FIG. 1 is a schematic diagram illustrating an example of an image forming apparatus according to the present invention. FIG. 3 is a schematic diagram illustrating an example of a configuration in which a photoconductor and a charging roller are arranged close to each other via a gap in the image forming apparatus of the present invention. It is the schematic which shows the other example of the image forming apparatus in this invention. FIG. 2 is a schematic diagram illustrating an example of a process cartridge for an image forming apparatus according to the present invention. It is the schematic which shows the structure of the supercritical processing apparatus used in order to form a photosensitive layer in an Example.

Explanation of symbols

1 conductive support 2 photosensitive layer 3 undercoat layer (or intermediate layer)
21 Photoconductor 22 Static elimination lamp 23 Charge charger 24 Image exposure unit 25 Development unit 26 Pre-transfer charger 27 Registration roller 28 Transfer paper 29 Transfer charger 30 Separation charger 31 Separation claw 32 Pre-cleaning charger 33 Fur brush 34 Blades 1C, 1M, 1Y, 1K photoreceptor 2C, 2M, 2Y, 2K charging member 3C, 3M, 3Y, 3K laser beam 4C, 4M, 4Y, 4K developing member 5C, 5M, 5Y, 5K cleaning member 6C, 6M, 6Y, 6K image forming element 7 Transfer paper 8 Paper feed roller 9 Registration roller 10 Transfer conveyor belts 11C, 11M, 11Y, 11K Transfer brush 12 Fixing device 101 Photoconductor [drum]
102 Charging means [contact charging device]
103 Exposure means (image exposure)
104 Developing means [Developing apparatus]
105 Recording medium [transfer body]
106 Transfer means (contact transfer device)
107 Cleaning means (cleaning unit)
V1 Valve 1
V2 Valve 2
V3 Valve 3
T Temperature sensor P Pressure sensor

Claims (14)

A method for producing an electrophotographic photoreceptor comprising a single photosensitive layer having at least a charge generation function, a hole transport function and / or an electron transport function on a conductive support,
The photosensitive layer has a cured resin layer formed by a curing reaction of a reactive compound having no charge transporting structure and a reactive compound having a charge transporting structure. A method for producing an electrophotographic photosensitive member, characterized by being formed by contacting a supercritical fluid and / or a subcritical fluid containing at least one substance.   2. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the cured resin layer is cured and formed by irradiating at least one of light, heat, and radiation.   The method for producing an electrophotographic photosensitive member according to claim 1, wherein the cured resin layer is made of at least one of a urethane resin, a phenol resin, an acrylic resin, a siloxane resin, and an epoxy resin.   The method for producing an electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the resin forming the cured resin layer contains a triarylamine structure.   The method for producing an electrophotographic photosensitive member according to claim 1, wherein the charge generation material is an azo pigment compound.   6. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the hole transport material is a triarylamine derivative.   7. The method for producing an electrophotographic photoreceptor according to claim 1, wherein the electron transport material is a naphthalene tetracarboxylic acid diimide derivative.   8. The supercritical fluid and / or subcritical fluid further contains at least one of an antioxidant, a light stabilizer, a dispersion aid, a lubricant, and a filler. A method for producing an electrophotographic photoreceptor.   9. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the supercritical fluid and / or subcritical fluid contains at least carbon dioxide.   The method for producing an electrophotographic photosensitive member according to claim 1, wherein an undercoat layer is provided between the conductive support and the photosensitive layer.   An electrophotographic photosensitive member produced by the method according to claim 1.   A charging means for charging at least the surface of the electrophotographic photosensitive member, an electrostatic latent image forming means for forming an electrostatic latent image on the electrophotographic photosensitive member, and a visible image formed by attaching toner to the electrostatic latent image An image forming apparatus comprising: a developing unit that transfers the visible image to a recording medium, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to claim 11. Image forming apparatus. At least a charging unit, an electrostatic latent image forming unit, a developing unit, and a transfer unit. The developing unit has a plurality of developing units filled with toners of different colors, and a plurality of electrons corresponding to the plurality of developing units. A tandem image forming apparatus provided with a photographic photoreceptor,
An image forming apparatus, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to claim 11.   Charging means for charging the surface of the electrophotographic photosensitive member, electrostatic latent image forming means for forming an electrostatic latent image on the electrophotographic photosensitive member, and developing means for forming a visible image by attaching toner to the electrostatic latent image 12. The electrophotographic photosensitive member according to claim 11, wherein the electrophotographic photosensitive member is selected from transfer means for transferring the visible image to a recording medium, and cleaning means for removing toner remaining on the surface of the electrophotographic photosensitive member after the transfer. A process cartridge for an image forming apparatus, wherein the process cartridge is integrated with a body and is detachable from an image forming apparatus main body.

Images