JP5151578B2 - Electrophotographic photosensitive member manufacturing method, electrophotographic photosensitive member, image forming apparatus, and process cartridge - Google Patents

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. More specifically, the present invention can stably output a high-quality image with high resolution and less occurrence of abnormal images. The present invention relates to a method for producing an electrophotographic photosensitive member having a single-layer type photosensitive layer, 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 functionally separated can be roughly classified.

  The laminated type photoconductor is functionally separated into at least a charge generation layer and a charge transport layer, and therefore has a relatively small influence on an oxidizing gas such as ozone and NOx, and is advantageous for high sensitivity. Since the layer-type photoreceptor contains the charge generation material and the charge transport material in one layer, the influence of the oxidizing gas is great, and the influence of the charge reduction and sensitivity reduction is also great. For these reasons, the multilayer type photoreceptor is now the mainstream.

  However, the single-layer type photoreceptor has many merits that are not found in the stacked-type photoreceptor. For example, a photoconductor has a structure in which a charge generated by a charge generating material is moved to the surface of the photoconductor by a charge transport material to form an electrostatic latent image. Then, the single layer type in which the photosensitive layer containing the charge generating substance is formed on the surface is more advantageous for improving the image quality. In addition, since the single-layer type photoreceptor contains both the hole transport material and the electron transport material in the photosensitive layer, the amount of ozone gas generated is small, and it can be applied to a positive charging system excellent in charging uniformity. Furthermore, since it is not necessary to superimpose many layers, there are few layer interfaces, the optical characteristics are improved, the production process of the photoconductor can be simplified, and the manufacturing cost can be reduced. It has great advantages such as a significant reduction in solvent usage. Therefore, in recent years, the attention of single-layer type photoreceptors has increased.

  The problems with single-layer photoconductors are that the above-mentioned static characteristics such as gas resistance, chargeability, and sensitivity are inferior. If a halftone image is output immediately after a high-contrast image is output, the previous output An abnormal image such as a “ghost” that appears as an afterimage is likely to occur. These are considered to be influenced by the fact that, unlike the multilayer type photoreceptor, the charge generation material is contained in the entire photosensitive layer, and the generated charges are likely to remain in the photosensitive layer.

  Conventionally, as mentioned in Patent Documents 1 to 6, etc., the above-mentioned problems are dealt with by controlling the oxidation potential mainly by improving materials such as hole transport materials and electron transport materials, or by selecting them. A method has been proposed. In particular, the electron transport material has a lower charge transport capability than the hole transport material, and an electron transport material having a high electron transport capability is very important in the development of a single layer type photoreceptor. With these conventional techniques, the characteristics of the single-layer type photoreceptor have been improved. However, the electrostatic characteristics and image characteristics are not satisfied as compared with the multilayer type photoreceptor, and the single-layer type photoreceptor is mainly used in an inexpensive image forming apparatus having a short life. It is a fact.

JP-A-6-130688 Japanese Patent No. 3183807 Japanese Patent No. 3471163 Japanese Patent No. 3273543 Japanese Patent No. 3239244 JP 2007-286536 A

  The present invention has been made in view of the problems of the above-described conventional techniques, and its purpose is to provide a single-layer type photosensitive layer that is excellent in terms of high image quality, low cost, improved productivity, and measures against environmental pollution. This is an electronic device that has a photoconductor with a basic structure, has achieved a significant improvement in electrostatic characteristics that could not be realized by conventional methods, has no abnormal images, and can output high-definition images unchanged even after repeated use. It is an object of the present invention to provide a method for producing a photographic photosensitive member, an electrophotographic photosensitive member produced thereby, an image forming apparatus using the same, and a process cartridge.

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 diligent investigation on the manufacturing method of the body, after forming a resin layer mainly composed of a binder resin on the conductive support, charge is generated in the resin layer using a supercritical fluid and / or a subcritical fluid. It has been found that these can be achieved by injecting at least one of a substance, a hole transport material and an electron transport material and providing a formed photosensitive layer. That is, the inventors have found that the above problems can be solved by the inventions described in the following [1] to [ 19 ], and have reached the present invention. Hereinafter, the present invention will be specifically described.

[1]: The above-mentioned problem is a method for producing an electrophotographic photosensitive member having a single photosensitive layer containing at least a charge generating material, a hole transporting material and an electron transporting material on a conductive support.
On a conductive support and a binder resin as a main component, after forming a resin layer containing a charge generating substance, halls to the resin layer transport material and electron transport material quality supercritical fluid and containing / or This is solved by a method for producing an electrophotographic photosensitive member, wherein the photosensitive layer is formed by bringing a subcritical fluid into contact therewith.

A conventional photosensitive layer obtained by coating on a conductive support using a coating liquid containing a charge transporting material has a concentration gradient in which the concentration of the charge transporting material decreases on the surface side of the photosensitive layer due to evaporation of the solvent. Is formed, which causes deterioration of electrostatic characteristics and resolution.
The effect is not so great because the charge transport layer in the multilayer photoreceptor is only a hole transport material, but the photosensitive layer in the single layer photoreceptor contains a charge generation material, a hole transport material and an electron transport material, and has a charge. Since the region where the light is generated is the entire photosensitive layer, the concentration gradient of the hole transport material or the electron transport material greatly affects the image quality.
According to the present invention [1 ] , a hole transport material and an electron transport material, or a charge generation material is injected into a resin layer formed on a conductive support, thereby producing a hole transport material and an electron. Transport material or charge generation material is uniformly contained in the resin layer, hole transport property and electron transport property are greatly increased, and electrostatic characteristics such as charge reduction, residual potential increase and sensitivity decrease are improved. In addition, since the charge remaining in the photosensitive layer can be reduced, it is possible to suppress the generation of ghost, thereby realizing high image quality.
It should be noted that the charge generation material has a negligible content compared to the hole transport material and the electron transport material, and the charge generation material has a generally low solubility in supercritical fluids and / or subcritical fluids. By containing the charge generation material in the layer in advance, and then injecting the charge transport material by the supercritical fluid and / or subcritical fluid, it is possible to control the content of the trace amount of the charge generation material, and more charge This is useful because the generated substance can be applied.

[ 2 ]: In the method for producing an electrophotographic photosensitive member according to [1 ], the binder resin contains a substituted or unsubstituted aryl group and / or arylene group in the structure.

[ 3 ]: The method for producing an electrophotographic photosensitive member according to [ 2 ] above, wherein the binder resin includes a bisphenol structure represented by the following general formula (I-1).

[In the formula (I-1), R ₁₀₁ and R ₁₀₂ each independently represents a substituted or unsubstituted alkyl group, aryl group or halogen atom. l and m are integers of 0 to 4, Y is a single bond, a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms, —O—, —S—, —SO—, —SO ₂ —. , -CO-, -CO-O-Z-O-CO- (wherein Z represents an aliphatic divalent group) or a divalent group represented by the following general formula (I-2) .

[In Formula (I-2), a represents an integer of 1 to 20, b represents an integer of 1 to 2000, R ₁₀₃ and R ₁₀₄ represent a substituted or unsubstituted alkyl group or aryl group. Here, R ₁₀₁ and R ₁₀₂ , and R ₁₀₃ and R ₁₀₄ may be the same or different. ]

[ 4 ]: In the method for producing an electrophotographic photosensitive member according to [ 2 ] or [ 3 ], the binder resin is at least one selected from polycarbonate and polyarylate.

According to the above [ 2 ] to [ 4 ], the binder resin forming the resin layer contains a substituted or unsubstituted aryl group and / or arylene group in the structure, and particularly represented by the general formula (I-1). By including the bisphenol structure, the injectability of the charge transport material by the supercritical fluid and / or the subcritical fluid is greatly enhanced, which is very effective for obtaining the effects of the present invention. Among these, when the binder resin forming the resin layer is polycarbonate or polyarylate, the tendency is further increased and is most effective in the present invention. This is presumably because the charge transport material injected into the resin layer contains many aryl groups and / or arylene groups, so that the compatibility with them increases and the injection property is improved. Further, since these aryl groups and / or arylene groups are included in the structure of the binder resin forming the resin layer, the free volume in the resin layer is increased, and a space for injecting the charge transport material is formed. It is thought to be for this purpose.

[ 5 ]: The method for producing an electrophotographic photosensitive member according to any one of [1] to [ 4 ], wherein the resin layer has a function as a charge transport material and a function of a binder resin. It is characterized by including.

In the present invention, it is possible and effective to use a polymer charge transport material for the binder resin forming the resin layer as described in [ 4 ] above. As a result, the wear resistance of the photoreceptor is improved, and the merit that durability can be improved is obtained.

[ 6 ]: The method for producing an electrophotographic photosensitive member according to any one of [1] to [ 5 ], wherein the charge generation material is at least one of an azo pigment or a phthalocyanine pigment.

[ 7 ]: The method for producing an electrophotographic photosensitive member according to any one of [1] to [ 6 ], wherein the charge generation material is a mixture of a plurality of charge generation materials having different structures. To do.

According to the above [ 6 ] and [ 7 ], the azo pigment or phthalocyanine pigment can be used stably even when brought into contact with a supercritical fluid and / or a subcritical fluid, and has excellent electrostatic characteristics and sensitivity. Can be used effectively. In addition, mixing the charge generating substance is useful because it enables further enhancement of sensitivity and control of the optical writing wavelength.

[ 8 ]: The method for producing an electrophotographic photosensitive member according to any one of [1] to [ 7 ], wherein the hole transport material is at least one of triphenylamine derivatives.

[ 9 ]: The method for producing an electrophotographic photosensitive member according to any one of [1] to [ 8 ] above, wherein the hole transport material is a mixture of a plurality of hole transport materials having different structures. To do.

According to the above [ 8 ] and [ 9 ], at least one of the triphenylamine derivatives is excellent in hole transport property and effective for high stabilization of electrostatic properties, and also has supercritical fluid and / or subcritical fluid. It is particularly effective because it has excellent injectability into the resin layer. In addition, mixing hole transport materials having different structures is useful because it can improve electrostatic characteristics and suppress image quality deterioration.

[ 10 ]: The method for producing an electrophotographic photosensitive member according to any one of [1] to [ 9 ] above, wherein the electron transport material is at least one naphthalenetetracarboxylic acid diimide derivative.

[ 11 ]: The method for producing an electrophotographic photosensitive member according to any one of [1] to [ 10 ] above, wherein the electron transport material is a mixture of a plurality of electron transport materials having different structures. To do.

According to the above [ 10 ] and [ 11 ], at least one of the naphthalenetetracarboxylic acid diimide derivatives is not only excellent in electron transport properties, but also to the resin layer via a supercritical fluid and / or a subcritical fluid. It is particularly effective because it has excellent injectability. In addition, mixing electron transport materials having different structures is useful because electrostatic characteristics can be improved and image quality deterioration can be suppressed.

[ 12 ]: In the method for producing an electrophotographic photosensitive member according to any one of [1] to [ 11 ], the supercritical fluid and / or the subcritical fluid may further include an antioxidant, a light stabilizer, a lubricant, It contains at least one kind of fine particles.

[13]: In the manufacturing method of the electrophotographic photosensitive member according to any one of [1] to [12], pre antioxidant to the resin layer, a light stabilizer, and at least one of a lubricant, selected from fine particles , a charge generating material, is contained, and then to form the photosensitive layer by contacting the supercritical fluid and / or subcritical fluid containing halls transport material and electron transport material quality in the resin layer Features.

According to the above [ 12 ] and [ 13 ], by containing each additive, for example, suppression of charge reduction caused by ozone gas or NOx gas, improvement of film quality, improvement of slipperiness of the surface of the photosensitive layer, irradiation of the photosensitive layer is performed. It is possible to suppress deterioration due to light, improve wear resistance, improve transfer efficiency, and improve cleaning properties.

[ 14 ]: In the method for producing an electrophotographic photosensitive member according to any one of [1] to [ 13 ], the supercritical fluid and / or subcritical fluid contains at least carbon dioxide.

According to the above [ 14 ], the critical temperature of carbon dioxide is particularly preferable because it is close to room temperature and excellent in 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 processing to the resin layer of the present invention.

[ 15 ]: In the method for producing an electrophotographic photosensitive member according to any one of [1] to [ 14 ], an undercoat layer is provided between the conductive support and the photosensitive layer. And

[ 15 ] According to the above [ 15 ], the undercoat layer prevents charge injection from the conductive support to the photosensitive layer, can prevent charge reduction, background smearing and moire, and can stably output a high quality image. It is also effective for preventing film peeling that may occur when contacting a supercritical fluid and / or subcritical fluid.

[ 16 ]: The above-mentioned problem is solved by an electrophotographic photoreceptor produced by the method according to any one of [1] to [ 15 ].

[ 17 ]: The above-described 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, wherein the electrophotographic photosensitive member is an electrophotographic apparatus according to [ 16 ]. This is solved by an image forming apparatus that is a photosensitive member.

[ 18 ]: 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 includes a plurality of developing units filled with toners of different colors. A tandem type image forming apparatus comprising a plurality of electrophotographic photosensitive members corresponding to a developing unit, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member described in [ 16 ]. It is solved by.

[ 19 ]: The above-described problems include 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 attaching toner 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 described in the above item 16 ] and detachable from the main body of the image forming apparatus.

According to the production method of the present invention, the resin layer provided on the conductive support is brought into contact with a supercritical fluid and / or subcritical fluid containing a charge transport material or a charge generation material, so that a charge is contained in the resin layer. Since the photosensitive layer is formed by injecting a transport material or a charge generation material, the charge transport material or the charge transport material can be uniformly contained in the photosensitive layer without causing a concentration gradient. As a result, problems such as reduced charging, increased residual potential, decreased sensitivity, etc. have been improved, and electrostatic characteristics are stabilized even when used repeatedly. High resolution and high-definition images can be output stably. In addition, the occurrence of abnormal images such as ghosts is suppressed, and a single-layer type photoreceptor that achieves both high image quality and high stability can be obtained. Furthermore, it has become possible to manufacture a photoconductor that has improved the production efficiency of the photoconductor, reduced the production cost, and reduced the load on the global environment. The production method of the present invention provides the following electrophotographic photosensitive member and an image forming apparatus using the same.
According to the electrophotographic photosensitive member of the present invention, it has been difficult to improve electrostatic characteristics (suppression of decrease in charging, increase in residual potential, decrease in sensitivity, etc.) and improvement of image quality (prevention of abnormal images such as ghosts). Realized with a single-layer type photoreceptor, there is little deterioration in image quality even after repeated use, and high-definition high-quality images can be output stably.
According to the image forming apparatus of the present invention, even if repeated image formation is performed, abnormal images such as background smudges and ghosts are few, and high-speed and highly stable image output is possible. In particular, according to the tandem image forming apparatus of the present invention, a full-color, high-definition image can be output at high speed and stably.
According to the process cartridge for an image forming apparatus of the present invention, high-speed and highly stable image output is possible, the handling is good, the maintainability is improved, and the cost is reduced.

The charge transport layer in the conventional multilayer photoreceptor functions if it transports only holes (or either electrons), whereas the photosensitive layer in the single-layer photoreceptor targeted by the present invention has a charge generation function. In addition, a function for transporting both holes and electrons is required. For example, when used in a positive charge, electrons generated in the charge generating material move to the surface of the photoreceptor and holes move to the conductive support.
However, it is known that a photosensitive layer produced by a normal coating method is formed with a concentration gradient on the surface side where the concentration of the charge transport material is lowered. This is because the charge transport material dissolved in the solvent of the photosensitive layer forming coating solution is applied to the conductive support and then the solvent evaporates. It is thought to move. Therefore, the thicker the photosensitive layer, the greater the difference in the concentration of the charge transport material between the surface side and the conductive support side. Although the concentration gradient of the charge transport material is affected by the difference in volatility of the solvent used, as long as the solvent evaporates after coating, the concentration gradient of the charge transport material is not limited.

  In the case of a layered type photoreceptor, even if a charge transport material concentration gradient is formed in the charge transport layer, the effect is not so great because the charge transport layer is hole transporting (or electron transporting). . However, the influence cannot be ignored in a single-layer type photosensitive layer containing both a hole transport material and an electron transport material. When used for positive charging, among the charges generated by the charge generating material, holes move to the conductive support side, so the effect is small, but electrons move to the surface, so electrons move in the surface region where the concentration of the electron transport material is low. Transportability will be significantly reduced. As a result, the mobility of electrons decreases, and charges are accumulated in the photosensitive layer, which may cause a decrease in sensitivity, an increase in residual potential, or generation of ghosts. Currently, hole transport materials have been developed and many materials having excellent properties have been disclosed, whereas electron transport materials are still not sufficient in terms of properties. Therefore, it can be said that the loss of the electron transport property due to the decrease in the concentration of the electron transport material in the surface area of the photoreceptor is a very important problem for the positively charged single layer photoreceptor.

  Further, in the single-layer type photosensitive layer, it is considered that the charge generation material is contained in the entire photosensitive layer, and accordingly, the charge generation region is also in the entire photosensitive layer, but it is the surface region that actually contributes to image formation. Expected to be. This has the merit that a high-definition image can be obtained, for example, the distance of charge movement is shortened in the process of the generated charge moving to the surface, so that the diffusion of the charge is reduced and the thickening of the characters and the scattering of the toner can be reduced. On the other hand, the formation of a concentration gradient that lowers the concentration of the charge transport material in the surface region is fatal in a single-layer type photoreceptor, and there is a limit to the improvement of characteristics only by the development of the charge transport material. I must say.

In the method for producing an electrophotographic photosensitive member (hereinafter sometimes abbreviated as “photosensitive member”) in the present invention, at least a charge generating material, a hole transporting material, and an electron transporting material are contained on a conductive support. In the method for producing an electrophotographic photoreceptor having a single photosensitive layer,
After forming a resin layer mainly composed of a binder resin on a conductive support, 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 is formed in the resin layer. The photosensitive layer is formed by contact.

  Supercritical fluid and / or subcritical fluid, as will be described in detail later, has both the properties of gas and liquid, and has excellent properties of permeability and diffusibility into the membrane. When the resin film is brought into contact with the resin film in a dissolved state, the charge transport material dissolved in the supercritical fluid and / or the subcritical fluid is injected into the resin film and uniformly contained in the film. As a result, a photosensitive layer without a concentration gradient of the charge transport material is formed, particularly the electron transport property is greatly increased, the charge accumulation in the single-layer type photosensitive layer is greatly reduced, the charge is decreased, the residual potential is increased, Electrostatic properties such as sensitivity reduction are significantly improved. Further, since the charge accumulated in the photosensitive layer can be reduced, it is possible to suppress the generation of ghosts, thereby realizing high image quality.

According to the present invention, since the fatal charge transport material concentration gradient in the single-layer type photoreceptor can be eliminated, the merit of high-definition image output in the single-layer photoreceptor is maximized. Further, since the residual solvent contained in the photosensitive layer is also removed by the supercritical fluid and / or the subcritical fluid, it is possible to obtain a further effect on the improvement of electrostatic characteristics. Furthermore, not only can the cost be reduced by simplifying the production process and improving the production efficiency, but also the load on the global environment can be reduced by reducing the amount of solvent used and the amount of coating liquid discarded.
In other words, by using a photoconductor having a single-layer type photosensitive layer, the merit of high-definition image formation, improvement in the productivity of the photoconductor, reduction in the use of solvents, and the like are achieved. Regarding the improvement of certain electrostatic fatigue characteristics and the suppression of abnormal images such as ghosts, as described above, a resin layer mainly composed of a binder resin is formed on a conductive support, and supercritical fluid and / or Alternatively, the problem can be solved by injecting a hole transport material and an electron transport material or a charge generation material using a subcritical fluid to form a photosensitive layer.

  In other words, according to the production method of the present invention, it is possible to suppress the concentration gradient of the charge transport material and the like that were inevitably formed by the conventional coating method, and to uniformly contain the charge transport material and the like in the photosensitive layer. It became. As a result, there is no occurrence of charge reduction, residual potential increase, sensitivity reduction, etc. even after repeated use, electrostatic characteristics are stabilized, high-definition images can be output stably, and abnormal images such as ghosts There are provided an electrophotographic photosensitive member having a single-layer type photosensitive layer that achieves both high image quality and high stability in which the occurrence of the phenomenon is suppressed, a method for producing the same, and an image forming apparatus using the same. Furthermore, it has become possible to manufacture a photoconductor that has improved the production efficiency of the photoconductor, reduced the production cost, and reduced the load on the global environment. This will be described in detail below.

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 excellent 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 that an effect of injecting a charge generating substance or a charge transporting substance into the resin layer is obtained, and even a subcritical fluid can be used effectively. Supercritical fluids have both gas and liquid characteristics as described above, and it is considered that a state close to a high-density liquid is particularly effective when contacting the resin layer. When, for example, carbon dioxide is used as the fluid to be treated from the point, it is a gas at normal temperature and normal pressure, but it can be said that it is effective even if it is not in a supercritical state when it is in a liquid 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,
1,3-dimethylbutane, benzene, chlorotrifluoromethane, dimethyl ether, and the like are 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 set freely depending on the material used, but the temperature is 20 to 200 ° C., preferably 30 to 150 ° 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 resin layer may be dissolved or decomposed. The use of the supercritical fluid or subcritical fluid in the present invention is intended to inject a charge generating substance or a charge transporting substance into the resin layer, and therefore the condition that the resin layer dissolves is not preferable. It is only necessary to set the temperature and pressure conditions while confirming the physical properties of the binder resin to be used, the physical properties of the charge generation material and the charge transport material, and the effects thereof. The fact that the conditions can be arbitrarily set is very useful for the practicality of the present invention. It is an excellent point.

  Further, as described above, it can 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 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.

  An apparatus for injecting a charge generation material, a charge transport material, or the like into a resin 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 the subcritical fluid. It may be a device. Specifically, a conductive support having a resin layer formed in a high-pressure cell and a substance such as a charge generation substance or a charge transport substance to be injected into the resin layer, for example, while introducing carbon dioxide, Increase temperature and pressure. As a result, the charge generating substance or charge transporting substance is dissolved in the supercritical fluid and / or subcritical fluid, and these charge generating substance or charge transporting substance is injected into the resin layer formed on the conductive support. The

  The state where the supercritical fluid and / or subcritical fluid containing the charge generation material, the charge transport material, etc. are in contact with the resin 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 transport material or the like, the two naturally come into contact with each other. Since the supercritical fluid and / or subcritical fluid has high solubility as described above and is excellent in diffusibility into the resin layer, the charge generation material dissolved in the supercritical fluid and / or subcritical fluid The charge transport material or the like is diffused and injected into the resin 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 charge generation materials or charge transport materials using supercritical fluids or subcritical fluids, substances to be contained in the photosensitive layer, such as antioxidants, light stabilizers, lubricants, etc. It is possible and effective to include these substances in the photosensitive layer by placing them in the 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. In the photosensitive layer (2) of FIGS. 1 and 2, after forming a resin layer mainly composed of a binder resin on a conductive support, at least one of a charge generation material, a hole transport material, and an electron transport material is formed on the resin layer. Formed by bringing a supercritical fluid and / or a subcritical fluid into contact with each other.
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 powders such as aluminum, nickel, iron, nichrome, copper, zinc, silver, and metal oxide powders 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. For example, sulfuric acid concentration: 10 to 20%, bath temperature: 5 to 25 ° C., current density: 1 to 4 A / dm ² , electric field voltage: 5 to 30 V, treatment time: treatment 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.

  <Regarding Photosensitive Layer> As described above, the photosensitive layer of the present invention is a single-layer type photosensitive layer. The photosensitive layer contains at least a binder resin, a charge generation material, a charge transport material, and the like. As a manufacturing method thereof, a resin layer made of a binder resin is formed on a conductive support, and a supercritical fluid and / or a subcritical fluid containing a charge transport material or a charge generation material is brought into contact with the resin layer. Thus, these materials are injected into the resin layer to form a photosensitive layer. Details will be described below.

<About Binder Resin> When forming a photosensitive layer, a resin layer is first formed on a conductive support using a binder resin. Any conventionally known resin can be used as the binder resin. For example, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, Polyarylate, polycarbonate, phenoxy resin, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly (N-vinylcarbazole), acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, Examples include alkyd resins. However, in the present application, when a charge transport material or the like is injected into a resin layer using a supercritical fluid and / or a subcritical fluid, if a curable resin that is three-dimensionally crosslinked with a binder resin constituting the resin layer is used, Injectability of transport materials may decrease. This is considered to be because the curable resin having a developed three-dimensional network structure is less likely to swell with respect to the supercritical fluid and / or the subcritical fluid. From these facts, the three-dimensionally cross-linked curable resin is not necessarily suitable as the binder resin constituting the resin layer in the present application, but rather it is preferable to use a thermoplastic resin.

  Among these binder resins, it is preferable to include an aryl group and / or an arylene group in the structure, and it is particularly preferable to include a bisphenol structure represented by the general formula (I-1). In the present invention, it is necessary to sufficiently inject a charge transport material or the like into the resin layer in order to function as a photoreceptor. For example, even if the charge transport material can be uniformly contained in the photosensitive layer, good electrostatic characteristics cannot be obtained if the absolute amount of the charge transport material is small. The injection property of such charge transport materials is affected by the solubility of the injected material in the supercritical fluid and / or subcritical fluid and the temperature and pressure conditions in the injection process, but also by the type of binder resin. .

  For example, in order to inject a charge transport material or the like into the resin layer, it is necessary to maintain a free volume that can be injected, or because the structure of the charge transport material has a large number of aromatic rings, It is preferable to increase the compatibility between the resin to be injected and the substance to be injected. For such reasons, the binder resin preferably includes an aryl group and / or an arylene group in the structure, and particularly preferably includes a bisphenol structure represented by the general formula (I-1). In the present invention, among these binder resins, polycarbonate or polyarylate can be used particularly effectively.

  In the present invention, a polymer charge transport material having both a function as a charge transport material and a function of a binder resin in the photosensitive layer is also preferably used. The photosensitive layer composed of these polymer charge transport materials is excellent in abrasion resistance, and the structure responsible for the charge transport function is bonded to the binder resin, so that the concentration gradient of the charge transport material is not formed. Effectively used in the present invention.

  As the polymer charge transport material, known materials can be used, but those exhibiting hole transport properties are known. In particular, a polycarbonate containing a triarylamine structure in the main chain and / or side chain is disclosed and can be used favorably in the present invention. Among them, polymer charge transport materials represented by the following general formulas (I) to (X) are favorably used, and these are exemplified below and specific examples are shown.

[In the formula (I), R ₁ , R ₂ and R ₃ are each independently a substituted or unsubstituted alkyl group or a halogen atom, R ₄ is a hydrogen atom or a substituted or unsubstituted alkyl group, R ₅ and R ₆ Is a substituted or unsubstituted aryl group, o, p, q are each independently an integer of 0-4, k, j are compositions, 0.1 ≦ k ≦ 1, 0 ≦ j ≦ 0.9, n Represents the number of repeating units and is an integer of 5 to 5000. X is an aliphatic divalent group, a cycloaliphatic divalent group, or the following general formula (I-1):

[In formula (I-1), R ₁₀₁ and R ₁₀₂ each independently represents a substituted or unsubstituted alkyl group, aryl group or halogen atom. l and m are integers of 0 to 4, Y is a single bond, a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms, —O—, —S—, —SO—, —SO ₂ —. , -CO-, -CO-O-Z-O-CO- (wherein Z represents an aliphatic divalent group) or a divalent group represented by the following general formula (I-2) .

(In Formula (I-2), a represents an integer of 1 to 20, b represents an integer of 1 to 2000, R ₁₀₃ and R ₁₀₄ represent a substituted or unsubstituted alkyl group or aryl group.) Here, R ₁₀₁ And R ₁₀₂ , and R ₁₀₃ and R ₁₀₄ may be the same or different. The divalent group represented by this is represented. ]
In the formula (I), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

[In the formula (II), R ₇ and R ₈ represent a substituted or unsubstituted aryl group, and Ar ₁ , Ar ₂ and Ar ₃ represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I). ]
In the formula (II), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

[In formula (III), R ₉ ,
R ₁₀ represents a substituted or unsubstituted aryl group, and Ar ₄ , Ar ₅ and Ar ₆ represent the same or different arylene groups.
X, k, j, and n are the same as in the formula (I). ]
In the formula (III), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

[In formula (IV), R ₁₁ ,
R ₁₂ represents a substituted or unsubstituted aryl group, Ar ₇ , Ar ₈ and Ar ₉ are the same or different arylene groups, and p represents an integer of 1 to 5. X, k, j and n are the same as in the case of the formula (I). ]
In the formula (IV), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

[In the formula (V), R ₁₃ and R ₁₄ are substituted or unsubstituted aryl groups, Ar ₁₀ , Ar ₁₁ and Ar ₁₂ are the same or different arylene groups,
X ₁ and X _{2 each} represents a substituted or unsubstituted ethylene group or a substituted or unsubstituted vinylene group.
X, k, j, and n are the same as in the formula (I). ]
In the formula (V), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

[In the formula (VI), R ₁₅ , R ₁₆ , R ₁₇ and R ₁₈ are substituted or unsubstituted aryl groups, Ar ₁₃ ,
Ar ₁₄ , Ar ₁₅ , Ar ₁₆ are the same or different arylene groups, Y ₁ , Y ₂ , Y ₃ are single bonds, substituted or unsubstituted alkylene groups, substituted or unsubstituted cycloalkylene groups, substituted or unsubstituted alkylenes Represents an ether group, an oxygen atom, a sulfur atom, or a vinylene group, which may be the same or different;
X, k, j, and n are the same as in the formula (I). ]
In the formula (VI), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

[In Formula (VII), R ₁₉ and R ₂₀ represent a hydrogen atom or a substituted or unsubstituted aryl group, and R ₁₉ and R ₂₀ may form a ring. Ar ₁₇ , Ar ₁₈ and Ar ₁₉ represent the same or different arylene groups. X, k, j, and n are the same as in the formula (I). ]
In the formula (VII), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

[In formula (VIII), R ₂₁ represents a substituted or unsubstituted aryl group, and Ar ₂₀ , Ar ₂₁ , Ar ₂₂ , Ar ₂₃ represent the same or different arylene groups.
X, k, j, and n are the same as in the formula (I). ]
In the formula (VIII), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

[In the formula (IX), R ₂₂ , R ₂₃ , R ₂₄ and R ₂₅ represent a substituted or unsubstituted aryl group, and Ar ₂₄ , Ar ₂₅ , Ar ₂₆ , Ar ₂₇ and Ar ₂₈ represent the same or different arylene groups. X, k, j, and n are the same as in the formula (I). ]
In the formula (IX), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

[In formula (X), R ₂₆ and R ₂₇ represent a substituted or unsubstituted aryl group, and Ar ₂₉ , Ar ₃₀ and Ar ₃₁ represent the same or different arylene groups.
X, k, j, and n are the same as in the formula (I). ]
In the formula (X), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

  Hereinafter, several compounds represented by the following structural formulas (1) to (34) will be shown as specific examples of the polycarbonate containing the triarylamine structure in the main chain and / or the side chain. It is not limited to compounds.

  These polymer charge transport materials having a triarylamine structure in the main chain and / or side chain are polymerized in the form of a homopolymer, a random copolymer, an alternating copolymer, and a block copolymer. And since these polymer charge transport materials have a role as a binder resin, it is necessary to have a film forming ability. Therefore, the molecular weight is suitably 10,000 to 500,000, preferably 50,000 to 400,000, as the polystyrene-equivalent molecular weight Mw in the measurement by GPC.

  Examples of these polymer charge transport materials include JP-A-8-269183, JP-A-9-71642, JP-A-9-104746, JP-A-9-272735, and JP-A-11-29634. JP-A-9-235367, JP-A-9-87376, JP-A-9-110976, JP-A-9-268226, JP-A-9-221544, JP-A-9-227669, Examples thereof include those disclosed in Kaihei 9-157378, JP-A-9-302084, JP-A-9-302085, and JP-A-2000-26590.

  As described above, there are many examples of use as the binder resin of the photosensitive layer, but the invention is not limited thereto, and any conventionally known resin can be used satisfactorily and effectively in the present invention. However, the present invention is prepared by forming a resin layer mainly composed of these binder resins and then injecting a charge generation material or a charge transport material into the resin layer. Is significantly different from a conventionally known technique in which the resin layer is formed in a state of being contained in the resin layer.

  The coating solution for forming the resin layer is obtained by dissolving at least the binder resin in an organic solvent. As the solvent used, conventionally known solvents such as tetrahydrofuran, dioxane, dioxolane, toluene, cyclohexanone, methyl ethyl ketone, xylene, acetone, diethyl ether, methyl ethyl ketone, dichloromethane, dichloroethane, and monochlorobenzene can be used. Among these, as an effective solvent, cyclic ethers such as tetrahydrofuran and dioxane, and aromatic hydrocarbons such as toluene and xylene are preferably used. These may be used singly or in combination of two or more.

  Further, a leveling agent may be added to the coating liquid for forming the resin layer as necessary, which is very effective for preventing coating film defects. For example, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and materials such as polymers and oligomers having a perfluoroalkyl group in the side chain are used, and the amount used is usually 0 to 5% by weight based on the binder resin. 0.001 wt% to 0.5 wt% is preferable, and 0.01 wt% to 0.1 wt% is more preferable.

  As a method for coating the resin layer, known methods such as dip coating, spray coating, bead coating, nozzle coating, spinner coating, ring coating, and the like can be used. After coating, it is manufactured by drying with the touch and then heating and drying in an oven or the like. Although the drying temperature of a resin layer changes with kinds of solvent contained in a coating liquid, it is preferable that it is 80-150 degreeC, and 100-140 degreeC is more preferable. The film thickness of the resin layer thus obtained is usually 5 to 50 μm because it is subsequently used as a photosensitive layer, preferably 10 to 40 μm, more preferably 15 to 30 μm.

<Regarding Charge Generating Substance> As the charge generating substance used in the present invention, a conventionally known material can be used. 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.

In the present invention, the impurities contained in the charge generation material are removed by bringing these charge generation materials into contact with the supercritical fluid and / or subcritical fluid in advance, and the charge generation material having a higher purity is introduced into the layer. It also has the merit that it can be contained. As a method for cleaning and purifying a charge generating substance with a supercritical fluid and / or a subcritical fluid, conventionally known methods can be used (for example, JP-A-7-181694, JP-A-2001-92165, JP 2002-138216 A, JP 2002-356627 A, etc.).
However, the charge generating material used for the photoreceptor is generally less soluble in a supercritical fluid and / or subcritical fluid than a charge transport material. Since the content of the charge generating material in the photosensitive layer is sufficiently smaller than the content of the charge transporting material, there may be no problem even if the solubility is low, but the charge generating material is mixed with the binder resin in advance. It is possible and effective to use a method of forming a resin layer and then injecting a charge transport material via a supercritical fluid and / or a subcritical fluid. Accordingly, the application range is not limited by the solubility of the charge generating substance to be contained, and a wide range of materials can be used. Further, it is advantageous in controlling the content of a very small amount of charge generating material, and is an effective method for producing a photoreceptor in which charge generating materials having different structures are mixed.

<Regarding Charge Transport Material> The charge transport material used in the present invention is roughly classified into a hole transport material that transports holes (holes) and an electron transport material that transports electrons. 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 containing a triphenylamine structure represented by the following general formula (a) are not only effective for high stabilization of electrostatic properties, but also supercritical fluids and / or Since it is excellent in injectability when it is contained in a subcritical fluid and injected into the resin layer, it is used particularly effectively.

[In Formula (a), R _{1 to} R ₁₂ 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. . ]

  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 (b).

[In the formula (b), m represents 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 1 to 4 carbon atoms. Represents an alkoxy group, a substituted or unsubstituted aryl group, and Ar ₁ represents a substituted or unsubstituted aryl group, the following general formula (c), or the following general formula (d). ]

Wherein (c), the R ₂₇ to R ₃₈ 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 formula (d), n represents 0, 1 or 2, and R _{39 to} R ₅₂ each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, or 1 to 4 carbon atoms. Represents an alkoxy group or a substituted or unsubstituted aryl group. ]

  In the present invention, specific examples of the hole transport material (HTM) represented by the above general formula which are particularly effectively used are described in Tables 1 and 2 below. However, these are examples of specific hole transport materials, and it is possible to obtain the effects of the present invention with any structure, and the present invention is limited to the following materials. is not.

  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 (eg, US Pat. No. 4,442,193, US Pat. No. 5,468,583, Patent No. 3292461, and Patent No. 3373783) are examples of electron transport. In addition to being excellent in performance, it is particularly effective because it is excellent in injectability when it is contained in a supercritical fluid and / or subcritical fluid and injected into the resin layer. The naphthalene tetracarboxylic acid diimide derivative in the present invention is a compound that contains at least a naphthalene tetracarboxylic acid diimide structure represented by the following general formula (e) in an electron transport material.

[In Formula (e), 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, or an alkoxy group having 1 to 4 carbon atoms. Represents a group, a substituted or 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 used more effectively in the present invention is represented by the following general formula (f).

[In the formula (f), 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, or an alkoxy group having 1 to 4 carbon atoms. A group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aralkyl group, and A is a hydrogen atom, a branched alkyl group, an unsubstituted linear alkyl group, an unsubstituted cyclic alkyl group, an alkyl substituted cyclic alkyl group, Represents an unsubstituted linear 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, an unsubstituted group Linear alkyl 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 A substituted or unsubstituted aryl group or a group represented by the following general formula (g):

[In the formula (g), R _{61 to} R ₆₄ are 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, substituted Or an unsubstituted cycloalkyl group, a substituted or unsubstituted aralkyl group, and C is a hydrogen atom, branched alkyl group, unsubstituted linear alkyl group, unsubstituted cyclic alkyl group, alkyl substituted cyclic alkyl group, unsubstituted straight chain 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 is represented. ] Is shown. ]

  Specific examples of electron transport materials (ETM) 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 photoconductor of the present invention can contain a substance other than a charge generation substance or a charge transport substance in the photosensitive layer, to stabilize electrostatic characteristics, improve gas resistance, improve transfer efficiency and cleaning performance. It is effective against this. 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 these are contained in a supercritical fluid and / or a subcritical fluid together with a charge generation material and a charge transport material and brought into contact with the resin layer, they are injected into the resin layer together with the charge generation material and the charge transport material. However, a material having extremely low solubility in the supercritical fluid and / or subcritical fluid or a material having a very large molecular size is difficult to be injected into the resin layer and is not suitable. In that case, a method in which these materials are preliminarily mixed with a binder resin and coated on a conductive support, and then a charge transport material is injected through a supercritical fluid and / or a subcritical fluid is also applied. It is possible and effective. Since the content of these additives is very small, this method is a very effective method for controlling the addition amount. In particular, although the fine particles depend on the particle size, they are often poorly soluble in the supercritical fluid and / or subcritical fluid, and are difficult to inject into the resin layer. In this case, these problems can be avoided and many effects can be obtained by adding the resin layer in advance before contacting with the supercritical fluid and / or subcritical fluid. However, when an additive that is highly soluble in the supercritical fluid and / or subcritical fluid is previously contained and then brought into contact with the supercritical fluid and / or subcritical fluid, the additive that has been contained in advance is the resin. There is a case where it comes off the layer. Therefore, a material having low solubility in the supercritical fluid and / or subcritical fluid is previously contained in the resin layer, and a material having high solubility is injected into the resin layer through the supercritical fluid and / or subcritical fluid. The method is more preferred.

Examples of these additives effective when contained in the photosensitive layer are shown below, but the present invention is not limited thereto.
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) Phenol 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-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis [ Me Len-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3′-bis (4′-hydroxy-3′-t-butylphenyl) buty Rick acid] glycol ester, tocopherols and the like. (B) Paraphenylenediamines: N-phenyl-N′-isopropyl-p-phenylenediamine, N, N′-di-s-butyl-p-phenylenediamine, N-phenyl-Ns-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-octyl hydroquinone, 2,6-didodecyl hydroquinone, 2-dodecyl hydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methyl hydroquinone, 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) Organic phosphorus 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, diisodecyl phthalate, diundecyl phthalate, ditridecyl phthalate, dicyclohexyl phthalate, butyl benzyl phthalate, butyl lauryl phthalate, methyl oleyl phthalate, octyl decyl phthalate, dibutyl fumarate, fumarate Dioctyl acid etc. (C) Aromatic carboxylic acid ester plasticizer: Trioctyl trimellitic acid, tri-n-octyl trimellitic acid, octyl oxybenzoate and the like. (D) Aliphatic dibasic acid ester plasticizer: Dibutyl adipate, di-n-hexyl adipate, di (2-ethylhexyl) adipate, di-n-octyl adipate, n-octyl adipate Decyl, diisodecyl adipate, dicapryl adipate, di (2-ethylhexyl) azelate, dimethyl sebacate, diethyl sebacate, dibutyl sebacate, di-n-octyl sebacate, di (2-ethylhexyl) sebacate, sebacic acid Di (2-ethoxyethyl), dioctyl succinate, diisodecyl succinate, dioctyl tetrahydrophthalate, di-n-octyl tetrahydrophthalate and the like. (E) Fatty acid ester derivatives: butyl oleate, glycerol monooleate, methyl acetylricinoleate, pentaerythritol ester, dipentaerythritol hexaester, triacetin, tributyrin and the like. (F) Oxyacid ester 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 etc. (H) Dihydric alcohol ester plasticizer: diethylene glycol dibenzoate, triethylene glycol di (2-ethylbutyrate) and the like. (I) Chlorine-containing plasticizer: Chlorinated paraffin, chlorinated diphenyl, chlorinated fatty acid methyl, methoxychlorinated fatty acid methyl and the like. (J) Polyester plasticizer: Polypropylene adipate, polypropylene sebacate, polyester, acetylated polyester, etc. (K) Sulfonic acid derivatives: p-toluenesulfonamide, o-toluenesulfonamide, p-toluenesulfoneethylamide, o-toluenesulfoneethylamide, toluenesulfone-N-ethylamide, p-toluenesulfone-N-cyclohexylamide, etc. . (L) Citric acid derivatives: Triethyl citrate, triethyl acetyl citrate, tributyl citrate, tributyl acetyl citrate, tri (2-ethylhexyl) citrate, n-octyldecyl acetyl citrate and the like. (M) Others: 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 compounds: liquid paraffin, paraffin wax, microwax, low-polymerized polyethylene and the like. (B) Fatty acid compounds: lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid and the like. (C) Fatty acid amide compounds: stearylamide, palmitylamide, oleylamide, methylenebisstearylamide, ethylenebisstearoamide and the like. (D) Ester compounds: 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 and the like. (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 and the like. (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) Salsylates: phenyl salsylate, 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: ethyl 2-cyano-3,3-diphenylacrylate, methyl 2-carbomethoxy-3-p-methoxyacrylate, and the like. (E) Quencher (metal complex 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. For example, by reducing the charge leakage from the conductive support during charging, it is possible to obtain the effect of suppressing scumming and the effect of suppressing the decrease in charging due to electrostatic fatigue. Further, it is possible to prevent the photosensitive layer from being peeled off from the conductive support in the process of bringing the photoreceptor into contact with the supercritical fluid and / or the subcritical fluid. Furthermore, it is possible to obtain an effect of suppressing the occurrence of image defects due to optical interference called moire.

  The undercoat layer is mainly composed of a binder resin. However, considering that the photosensitive layer is laminated thereon, these resins are preferably resins having high solvent resistance with respect to general organic solvents. 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.

  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. These fillers can also be subjected to a surface treatment, and for example, those treated with a silane coupling agent, a titanium coupling agent, a chromium coupling agent or the like can be used. 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.

  In order to reduce charges trapped in the undercoat layer or at the interface between the undercoat layer and the photosensitive layer, the undercoat layer may contain a charge transport material or the like. The charge transport material to be contained is classified into a hole transport material or an electron transport material depending on whether it is positively charged or negatively charged. As these charge transport materials, well-known materials capable of transporting charges can be used in addition to the materials described for the photosensitive layer.

  The coating liquid for forming the undercoat layer contains a binder resin and a solvent as main components. When a metal oxide or the like is contained, it can be obtained by dispersing the metal oxide and the 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. The thickness of the undercoat layer is preferably 0.05 to 20 μm, and more preferably 0.2 to 7 μm. However, when the undercoat layer contains a metal oxide or a material having a charge transport function and the resistance is controlled, it can be used well even if the film thickness is relatively thick, depending on the material, about 2 to 20 μm However, when these materials are not contained in the undercoat layer and only the binder resin is used, the residual potential increases remarkably, so that the film thickness is 2 μm or less. It is more preferable to set it to 1 μm or less. 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 manufacturing method>
The method for producing an electrophotographic photosensitive member of the present invention includes a resin layer forming step of forming a resin layer containing a binder resin as a main component on a conductive substrate, and a hole transport material and an electron transport material, or charge generation on the resin layer. And a supercritical fluid processing step of contacting a supercritical fluid and / or a subcritical fluid containing at least one substance. That is, a resin layer made of a binder resin is applied and formed on a conductive support (if necessary, an undercoat layer is provided thereon) using a coating liquid, and then a charge transport material or charge This is a procedure for injecting a supercritical fluid and / or a subcritical fluid containing the generated substance.

  As a method for applying the resin layer on the conductive support, a conventionally known method can be used. 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 resin layer containing a binder resin as a main component is composed of various binder resins and, if necessary, additives such as a leveling agent and an organic solvent.
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, Halogens such as dichloromethane, dichloroethane, trichloroethane, chlorobenzene, aromatics such as benzene, toluene, xylene, cellosolves such as methyl cellosolve, ethyl cellosolve, cellosolve acetate, etc. May be.

  In the present invention, the resin layer is further brought into contact with a supercritical fluid and / or a subcritical fluid containing various materials such as a charge transport material, and optionally charge generating materials, additives, and fine particles, and injected into the resin layer. As a result, a photosensitive layer is formed. This process is performed using an apparatus as shown in FIG. 8 as an example.

  A pressure-sensitive reaction cell (84) is filled with at least a conductive support having a resin layer formed thereon and a material to be injected such as a charge transport material, and carbon dioxide and the like are further supplied into the pressure-resistant reaction cell. The temperature is adjusted to a predetermined temperature and pressure by a temperature controller (90, if necessary 93) and a temperature control jacket (83), and kept in that state. At this time, in the pressure-resistant reaction cell, the substance to be injected into the layer such as the charge transport material is dissolved in the supercritical fluid and / or the subcritical fluid, and the supercritical fluid having both the characteristics of gas and liquid and / or Alternatively, the subcritical fluid permeates into the resin layer formed on the conductive support, so that a charge transport material or the like dissolved therein is injected into the resin layer. The temperature and pressure can be arbitrarily set according to the solubility of the substance to be injected, and the content of the constituent material in the photosensitive layer can be controlled by these setting conditions, the amount of the substance to be injected, etc. .

  Thereafter, the temperature and pressure in the pressure-resistant reaction cell are gradually lowered and reduced to room temperature and atmospheric pressure while controlling the temperature regulator and back pressure valve (85) of the temperature control jacket, thereby the pressure-resistant reaction cell (84). The supercritical fluid and / or subcritical fluid in the inside becomes a gas and can be taken out in a state where a charge transport material or the like is injected into the resin layer, and a photoconductor is manufactured. A more specific process will be described in the embodiment.

  The set temperature and pressure in the pressure-resistant reaction cell vary depending on the supercritical fluid and / or subcritical fluid used, the material to be injected, or the apparatus, but in the present invention, it is most preferable to use carbon dioxide. -200 degreeC and 5-100 Mpa, Preferably 30-100 degreeC and 7-70 Mpa are suitable. Further, the holding time in this state is completed in several tens of minutes to several tens of hours, and is usually completed in several hours.

  The injection process of charge transport materials by supercritical fluid and / or subcritical fluid can be performed one by one or multiple samples at the same time, which is effective for reducing production costs. It is. In the pressure-resistant reaction cell, the charge transport material is dissolved in the supercritical fluid and / or subcritical fluid. is there.

  In the photosensitive layer produced by the above method, the content of the charge generating substance is 0.05 to 20% by weight, preferably 0.1 to 5% by weight, based on the binder resin. The content of the hole transporting material is 5 to 300% by weight, preferably 20 to 150% by weight, based on the binder resin, and the content of the electron transporting material is 5 to 300% by weight based on the binder resin. %, Preferably 10 to 150% by weight. The total amount of the hole transport material and the electron transport material (charge transport material) is 20 to 300% by weight, preferably 30 to 200% by weight, based on the binder resin.

  If the content of the charge generating substance is too small, an increase in residual potential and sensitivity deterioration are observed, and if the content is too large, problems such as a decrease in charging, a delay in charging, and an increase in dark decay become problems. As described above, in the case of a charge generation material, since the content needs to be controlled, it is better to pre-contain it in the resin layer than injecting it into the supercritical fluid and / or subcritical fluid. Often preferred. On the other hand, if the content of the charge transport material is too small, a residual potential increase and sensitivity deterioration are observed. However, if the content is too large, no serious problem occurs. Therefore, since more charge transport materials can be injected, it is easy to achieve both wear resistance and electrostatic characteristics, and high-quality images can be output stably even after repeated use over a long period of time. Become.

  Moreover, materials such as an antioxidant, a plasticizer, a light stabilizer, a lubricant and fine particles can be contained in the photosensitive layer as necessary. In this case, there are a method in which it is contained in a supercritical fluid and / or a subcritical fluid and injected together with a charge transport material and the like, and a method in which it is preliminarily contained in the resin layer, both of which can be used effectively. However, if a material having high solubility of the supercritical fluid and / or subcritical fluid is previously contained and then brought into contact with the supercritical fluid and / or subcritical fluid, they may be detached from the resin layer. Therefore, it is preferable to apply the former method to a material having high solubility in a supercritical fluid and / or a subcritical fluid, and conversely apply the latter method to a material having low solubility. Additives such as antioxidants and plasticizers are 0.01 to 30% by weight, preferably 0.1 to 10% by weight with respect to the binder resin, and lubricants and fine particles are 0.1 to 50% with respect to the binder resin. % By weight, preferably 0.5-30% by weight is suitable.

  The thickness of the resin layer, that is, the photosensitive layer is preferably 5 to 50 μm, and more preferably 10 to 30 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. However, if the film thickness is larger 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.

  One of the effects of the present invention is that the charge transport material contained in the photosensitive layer or the material injected into the other resin layer is uniformly contained in the photosensitive layer without forming a concentration gradient. Is Rukoto. In order to confirm whether or not the charge transport material is uniformly contained in the photosensitive layer, there are methods using FT-IR and ATR methods. The front and back surfaces of the photosensitive layer on the conductive support are analyzed using the FT-IR and ATR methods, and the intensity ratio between the single peak of the charge transport material and the single peak of the binder resin is calculated from the obtained IR spectrum. However, this is possible by comparing the front and back surfaces.

  Specifically, the photosensitive layer is forcibly removed from the conductive support, the peak intensity ratio of the charge transport material to the binder resin at the interface (back surface) of the photosensitive layer on the conductive support side, and the charge transport on the surface of the photosensitive layer. Quantitative evaluation is possible by determining the peak intensity ratio of the substance to the binder resin and determining the ratio. Alternatively, the evaluation can be performed by cutting the photosensitive layer obliquely and obtaining the IR spectrum in the same manner for the cut surface. In addition, it can also evaluate by shaving off the surface and back surface of a photosensitive layer, and analyzing from the powder. The present invention is not limited to the analysis method as long as it can quantitatively evaluate the concentration of the charge transport material relative to the binder resin.

  In the present invention, an effect can be obtained if it is uniformly contained in the photosensitive layer, and specifically, with respect to the concentration of the hole transport material and the electron transport material contained in the conductive support side interface of the photosensitive layer, The concentration ratio of the hole transport material and the electron transport material contained on the surface of the photosensitive layer is more preferably 0.9 or more and 1.1 or less.

  <Regarding 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 the photoconductor described in FIGS. The photoreceptor (21) has a drum shape, but may be a sheet or an endless belt. For charging charger (23), pre-transfer charger (26), transfer charger (29), separation charger (30) and pre-cleaning charger (32), in addition to corotron, scorotron, solid state charger (solid state charger) A roller-shaped charging member or a brush-shaped charging member is used, 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 charging member 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, by disposing the charging roller (43) close to the photoreceptor (41) via a gap as shown in FIG. 4, contaminants are less likely to adhere to the charging roller (43) 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 (41) and the charging roller (43) is preferably small, and is 100 μm or less, more preferably 50 μm or less. However, by making the charging roller (43) non-contact, the discharge becomes non-uniform and the photosensitive member (41) 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 roller (43) and the influence of the charging property. Thus, by using in combination with the photoconductor (41) 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, brush, etc. 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) are drum-shaped photoconductors, and the photoconductor is the photoconductor 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) as 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, in FIG. 9, the charging member is in contact with the photosensitive member, but by using a charging mechanism as shown in FIG. 4, an appropriate gap (about 10 to 200 μm) is provided between them. 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 well.

  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 [transfer apparatus]. The photoconductor [drum] (101) is the photoconductor shown in FIG.

  Hereinafter, although an example is given and the present invention is explained, the present invention is not restricted by these examples. All parts are parts by weight.

  (Example 1) After coating by an dip coating method using an undercoat layer coating solution having the following composition on an aluminum base tube having an outer diameter of 30 mm, it was dried by heating at 130 ° C for 10 minutes, and about 0.3 µm An undercoat layer was formed. [Coating liquid for undercoat layer] N-methoxymethylated nylon: FR101 (manufactured by Lead City) Methanol n-butanol <Mixing conditions> N-methoxymethylated nylon / methanol / n-butanol = 5/70 / 30 (part)

  Next, in order to form a resin layer, first, a pigment and a solvent having the following composition were put in a glass pot and dispersed for 3 hours using a PSZ ball having a diameter of 0.5 mm to prepare a pigment dispersion. [Pigment dispersion] Charge generation material (Fastogen Blue 8120B (metal-free phthalocyanine pigment, manufactured by Dainippon Ink & Chemicals, Inc.) Tetrahydrofuran <Mixing conditions> Charge generation material / tetrahydrofuran = 3/97 (part)

  Then, the coating liquid for resin layer formation of the following composition was produced using the said pigment dispersion liquid. This was applied onto the undercoat layer by a dip coating method, followed by heat drying at 120 ° C. for 20 minutes to form a resin layer of about 23 μm. [Coating liquid for resin layer] Pigment dispersion liquid Polycarbonate (TS-2040 (Z type), manufactured by Teijin Chemicals Ltd.) Silicone oil (100 cSt, manufactured by Shin-Etsu Chemical Co., Ltd.) Tetrahydrofuran <Mixing conditions> Pigment dispersion liquid / Polycarbonate / silicone oil / tetrahydrofuran = 30/50 / 0.01 / 400 (part)

<Injection treatment with supercritical fluid> Next, an aluminum element tube having the resin layer formed thereon, 1.5 parts of the hole transport material indicated by the HTM4 and 1.5 parts of the electron transport material indicated by the ETM2 are illustrated. It put into the pressure | voltage resistant reaction cell (84) of the supercritical processing apparatus shown in 8, and all the valves were closed. Thereafter, the valve 1 (89) and the valve 3 (86) are opened, and the carbon dioxide is supplied from the supply cylinder (CO ₂ cylinder) (92) to the pressure-resistant reaction cell while controlling the pressure with the back pressure valve (85). Temperature and pressure are adjusted to 120 ° C and 20MPa over about 20 minutes, while the pressure regulator 1 (90) and temperature controller (83) are used to expand the pressure-resistant reaction cell, and the temperature and pressure are stable. And then kept for 2 hours. Then, while controlling the temperature and pressure in the pressure-resistant reaction cell (84) while controlling the temperature control jacket and the back pressure valve, the temperature is gradually lowered and reduced over about 20 minutes until it reaches 25 ° C. and atmospheric pressure. An electrophotographic photosensitive member was produced. 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 hole transport material was changed to HTM9 in Example 1.

  Example 3 An electrophotographic photosensitive member of the present invention was produced in the same manner as in Example 1 except that the hole transport material was changed to the hole transport material represented by the following structural formula (h) in Example 1. did.

  (Example 4) The electrophotographic photosensitive member of the present invention was produced in the same manner as in Example 1 except that the electron transport material in Example 1 was changed to the electron transport material represented by the following structural formula (i). did.

  (Example 5) In Example 1, except that the addition amount of the hole transport material HTM4 was changed to 0.5 parts and 1.0 part of the hole transport material HTM17 was further added, the same procedure as in Example 1 was performed. An electrophotographic photoreceptor of the invention was prepared.

  (Example 6) In Example 1, except that the addition amount of the electron transport material ETM2 was changed to 0.5 part and 1.0 part of the electron transport material ETM7 was further added, the same procedure as in Example 1 was performed. An electrophotographic photoreceptor of the invention was prepared.

  (Example 7) In Example 1, the electrophotographic photosensitive material of the present invention was used in the same manner as Example 1 except that the resin layer was coated using the pigment dispersion liquid and the resin layer coating liquid having the following composition. The body was made. [Pigment dispersion] ・ Charge generating substance (azo pigment of the following structural formula (j)) ・ Cyclohexanone

  <Mixing conditions> Charge generating material / cyclohexanone = 3/97 (part)

  Then, the coating liquid for resin layer formation of the following composition was produced using the said pigment dispersion liquid. This was applied onto the undercoat layer by a dip coating method, followed by heat drying at 130 ° C. for 20 minutes to form a resin layer of about 23 μm. [Coating fluid for resin layer]-Pigment dispersion-Polycarbonate (TS-2040 (Z type), manufactured by Teijin Chemicals Ltd.), Silicone oil (100 cSt, manufactured by Shin-Etsu Chemical Co., Ltd.), Tetrahydrofuran <Mixing conditions> Pigment dispersion / Polycarbonate / silicone oil / tetrahydrofuran = 30/50 / 0.01 / 400 (part)

  Further, an electrophotographic photoreceptor of the present invention was produced in the same manner as in Example 1 except that 0.5 part of the following antioxidant was added together with the charge transport material in the injection process with the supercritical fluid. Antioxidant: (Antioxidant having the following structural formula (k))

  (Example 8) In Example 7, except that the content of the azo pigment was changed from 1 part to 0.5 part and 0.5 part of titanyl phthalocyanine shown in the X-ray diffraction spectrum of FIG. 7 was added. In the same manner as in Example 7, an electrophotographic photoreceptor of the present invention was produced.

Example 9 The electrophotographic photosensitive member of the present invention was produced in the same manner as in Example 1 except that the binder resin used in the resin layer coating solution in Example 1 was changed to the following binder resin. did.
・ Polyarylate (U polymer 100, manufactured by Unitika)

  Example 10 Example 1 is the same as Example 1 except that the resin layer coating solution is changed to a coating solution having the following composition and no hole charge transport material is added in the supercritical fluid injection process. The electrophotographic photoreceptor of the present invention was produced in the same manner as described above. [Resin Layer Coating Liquid] Pigment Dispersion Liquid Polymer Charge Transport Material (Structural Formula (l) below, Weight Average Molecular Weight 101,300) Silicone Oil (100 cSt, Shin-Etsu Chemical Co., Ltd.) Tetrahydrofuran

  <Mixing conditions> Pigment dispersion / polymer charge transport material / silicone oil / tetrahydrofuran = 30/85 / 0.015 / 400 (part)

  (Example 11) In Example 10, except that the polymer charge transporting material contained in the resin layer coating solution was changed to the following polymer charge transporting material, the same as in Example 10 was followed. An electrophotographic photosensitive member was produced.・ Polymer charge transport material (the following structural formula (m), weight average molecular weight 68,200)

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

  Example 13 An electrophotographic photosensitive member was produced in the same manner as in Example 12 except that the following fluororesin fine particles were further added to the resin layer coating solution. Fine particles: MPE-056 (perfluoroalkoxy resin particles) (manufactured by Mitsui Fluorochemicals) Dispersion aid: Modiper F210 (manufactured by NOF Corporation) <Mixing conditions> Pigment dispersion / polycarbonate / silicone oil / fine particles / dispersion aid Tetrahydrofuran = 30/50 / 0.01 / 5/1/400 (part)

  (Comparative Example 1) In Example 1, the resin layer-forming coating solution was changed to the following photosensitive layer-forming coating solution and applied, and then an injection treatment with a supercritical fluid was not performed, and 130 ° C 20 An electrophotographic photosensitive member was prepared by forming a photosensitive layer having a thickness of about 23 μm. [Coating solution for forming photosensitive layer] Charge generating substance (Fastogen Blue 8120B (metal-free phthalocyanine pigment, manufactured by Dainippon Ink and Chemicals, Inc.) Hole transport material (HTM4) Electron transport material (ETM2) Polycarbonate (TS-2040 ( Z type), manufactured by Teijin Kasei Co., Ltd. Tetrahydrofuran Silicone oil (100 cs, manufactured by Shin-Etsu Chemical Co., Ltd.) <Mixing conditions> Charge generation material / hole transport material / electron transport material / polycarbonate / silicone oil / tetrahydrofuran = 1/25 / 25/50 / 0.01 / 400 (part)

  Comparative Example 2 An electrophotographic photosensitive member was produced in the same manner as in Comparative Example 1 except that the film thickness of the photosensitive layer was changed to 33 μm.

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

  (Comparative Example 4) A charge generation layer was applied onto an aluminum tube having an outer diameter of 30 mm using a charge generation layer coating liquid having the following composition, followed by heating and drying at 130 ° C for 20 minutes, about 0.2 µm. The charge generation layer was formed. [Coating liquid for charge generation layer] Metal-free phthalocyanine pigment: Fastogen Blue 8120B (manufactured by Dainippon Ink & Chemicals) Polyvinyl butyral (BL-1, manufactured by Sekisui Chemical Co., Ltd.) 2-butanone Cyclohexanone <Mixing conditions> Charge generation Substance / polyvinyl butyral / 2-butanone / cyclohexanone = 2/1/30/70 (part)

Subsequently, a charge transport layer was applied using a coating liquid for charge transport layer having the following composition, followed by heating and drying at 130 ° C. for 20 minutes to form an approximately 22 μm charge transport layer, thereby producing an electrophotographic photosensitive member. .
[Coating liquid for charge transport layer] Charge transport material (ETM2) Polycarbonate (TS-2040 (Z type), manufactured by Teijin Chemicals) Tetrahydrofuran Silicone oil (100 cs, manufactured by Shin-Etsu Chemical Co., Ltd.) <Mixing conditions> Charge transport material / polycarbonate / silicone oil / tetrahydrofuran = 50/50 / 0.01 / 400 (part)

  (Comparative Example 5) The electrophotographic photosensitive member of the present invention is the same as Example 1 except that the temperature and pressure conditions of the supercritical fluid injection process are adjusted to 20 ° C and 5 MPa in Example 1. Was made.

  [Durability Test] The photoconductors of Examples 1 to 13 and Comparative Examples 1 to 5 manufactured as described above were mounted on an electrophotographic process cartridge, and a modified image forming apparatus (IPSiO SP C411 manufactured by Ricoh Company). Mounted on. The charger was replaced with a power pack or the like so as to be positively charged, and the toner and developer were also replaced with those for positively charging. In addition, the image exposure light source was replaced with a 655 nm or 780 nm semiconductor laser, and the amount of exposure light was adjusted each time with a sample so that the light attenuation characteristics of the photoconductor became substantially constant. 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 50,000 sheets), the exposure portion potential (VL) was measured and the image quality of the output image samples was evaluated. In the image evaluation, the resolution is obtained by outputting a test chart, the background stain is produced by outputting a solid white image without writing, the image density unevenness is produced by outputting an entire halftone image having a halftone density, and the output of the chart shown in FIG. A ghost was evaluated. Each image evaluation level was classified into the following four levels. ◎: Image quality degradation is hardly observed and is very good level ○: Image quality degradation is slightly seen, but it can be judged that there is no problem △: Image quality degradation is clearly recognized and is regarded as a problem ×: Image quality degradation These results are shown in Table 3 below.

  As is clear from the evaluation results in Table 5 above, the photoreceptor of the present invention has a sufficiently low exposure area potential, excellent electrostatic characteristics, and almost no increase in the exposure area potential even after repeated use. High stabilization of electrostatic characteristics was realized. In addition, the image quality is high, the occurrence of ghosts and background stains is small, and it is very good. The image quality is almost maintained even after repeated use. On the other hand, the photoconductor of the comparative example by the normal coating method showed a decrease in charge, a decrease in sensitivity, an increase in residual potential, etc. due to repeated use, a noticeable decrease in image quality due to fatigue due to scumming and ghosting. It was. By increasing the film thickness of the photosensitive layer, the occurrence of scumming was somewhat reduced, but the degree of ghost was deteriorated and the image density was lowered, and the image quality was not improved. In addition, in the case of a laminated type photoreceptor provided with an electron transport layer on the surface, a significant increase in the potential of the exposed area was observed, the image density was significantly reduced, and a reduction in resolution was also observed. Further, if the injection process using the supercritical fluid is not performed, and the temperature and pressure conditions are too low and the supercritical fluid and / or the subcritical fluid are not formed even if the injection process is performed, the charge transport material is not a resin layer. No photoconductor properties were shown. As is clear from the above results, the photoconductor of the present invention can output a higher definition image than the multilayer photoconductor, and has excellent electrostatic characteristics, and the effect is stably maintained even after repeated use. A possible photoreceptor could be realized by using a supercritical fluid and / or a subcritical fluid. 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 an X-ray diffraction spectrum diagram of the charge generation material used in the examples, the vertical axis represents the counts per second (cps: counts per second), and the horizontal axis represents the angle (2θ). It is a schematic block diagram of the supercritical processing apparatus used in order to form a photosensitive layer in an Example. It is the schematic of the chart used for evaluation of the ghost in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Photosensitive layer 3 Undercoat layer [or intermediate | middle layer] 1C, 1M, 1Y, 1K Photoconductor 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 transport belt 11C, 11M, 11Y, 11K transfer brush 12 fixing device 21 photosensitive Body 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 Charger before cleaning 33 Far brush 34 Blade 41 Photoconductor 43 Charging roller 81 Stirring Device 82 Stirrer 83 Temperature control jacket 4 pressure-resistant reaction cell 85 back pressure valve 86 valve 3 (V3) 87 Pressure sensor 88 Temperature sensor 89 valve 1 (V1) 90 pressure pump 191 Valve ₂ (V2) 92 CO 2 cylinder 93 pressurizing pump 294 entrainer T Temperature Sensor P Pressure Sensor 101 Photoconductor [drum] 102 Charging means [contact charging device] 103 Exposure means [image exposure] 104 Development means [developing device] 105 Recording medium [transfer body] 106 Transfer means [transfer device] 107 Cleaning means [cleaning unit]

Claims (19)

In a method for producing an electrophotographic photoreceptor having a single photosensitive layer containing at least a charge generating material, a hole transport material and an electron transport material on a conductive support,
On a conductive support and a binder resin as a main component, after forming a resin layer containing a charge generating substance, halls to the resin layer transport material and electron transport material quality supercritical fluid and containing / or A method for producing an electrophotographic photosensitive member, wherein the photosensitive layer is formed by contacting a subcritical fluid. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the binder resin contains a substituted or unsubstituted aryl group and / or arylene group in the structure. The method for producing an electrophotographic photoreceptor according to claim 2 , wherein the binder resin contains a bisphenol structure represented by the following general formula (I-1).

[In the formula (I-1), R ₁₀₁ and R ₁₀₂ each independently represents a substituted or unsubstituted alkyl group, aryl group or halogen atom. l and m are integers of 0 to 4, Y is a single bond, a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms, —O—, —S—, —SO—, —SO ₂ —. , -CO-, -CO-O-Z-O-CO- (wherein Z represents an aliphatic divalent group) or a divalent group represented by the following general formula (I-2) .

[In Formula (I-2), a represents an integer of 1 to 20, b represents an integer of 1 to 2000, R ₁₀₃ and R ₁₀₄ represent a substituted or unsubstituted alkyl group or aryl group. Here, R ₁₀₁ and R ₁₀₂ , and R ₁₀₃ and R ₁₀₄ may be the same or different. ] Said binder resin, method for producing an electrophotographic photosensitive member according to claim 2 or 3, characterized in that at least one selected from polycarbonate, and polyarylate. The resin layer is, the manufacturing method of the electrophotographic photosensitive member according to any one of claims 1 to 4, characterized in that it contains a polymeric charge transport material having both functions of the binder resin as the charge transporting material . The charge generating material, a manufacturing method of the electrophotographic photosensitive member according to any one of claims 1 to 5, characterized in that at least one of the azo pigments or phthalocyanine pigments. The charge generating material, a manufacturing method of the electrophotographic photosensitive member according to any one of claims 1 to 6, characterized in that the structure together is a mixture of different charge generating materials. The hole transport material, method for producing an electrophotographic photosensitive member according to any one of claims 1 to 7, characterized in that at least one of the triphenylamine derivative. The hole transport material, method for producing an electrophotographic photosensitive member according to any one of claims 1 to 8, characterized in that structure to one another is a mixture of different hole transport materials. The electron transport material, method for producing an electrophotographic photosensitive member according to any one of claims 1 to 9, characterized in that at least one of naphthalene tetracarboxylic acid diimide derivative. The electron transport material, method for producing an electrophotographic photosensitive member according to any one of claims 1 to 10, characterized in that structure to one another is a mixture of different electron transport materials. Wherein the supercritical fluid and / or subcritical fluid, further antioxidants, light stabilizers, lubricants, electrophotographic photosensitive according to any one of claims 1 to 11, characterized in that at least one of fine particles are contained Body manufacturing method. Pre antioxidant to the resin layer, containing a light stabilizer, and at least one lubricant, selected from fine particles, a charge generating material, a is contained, followed halls in the resin layer transport material and an electron transport Substance the method for producing an electrophotographic photosensitive member according to any one of claims 1 to 12 by contacting the the supercritical fluid and / or subcritical fluid and forming the photosensitive layer. The supercritical fluid and / or subcritical fluid, method for producing an electrophotographic photosensitive member according to any one of claims 1 to 13, characterized in that it contains at least carbon dioxide. The method for producing an electrophotographic photosensitive member according to any one of claims 1 to 14 between the conductive support and the photosensitive layer, wherein the undercoat layer is provided. An electrophotographic photosensitive member, characterized in that it is manufactured by a method according to any one of claims 1 to 15. 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 16. 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. 17. An image forming apparatus comprising a tandem type image forming apparatus provided with a photographic photosensitive body, wherein the electrophotographic photosensitive body is the electrophotographic photosensitive body according to claim 16 . 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 The electrophotographic photosensitive member according to claim 16 , wherein the electrophotographic photosensitive member is selected from: a transfer unit that transfers the visible image to a recording medium; and a cleaning unit that removes toner remaining on the surface of the electrophotographic photosensitive member after 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.