JP2005189830A - Image formation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image formation apparatus which is free of occurrence of an abnormal image and produces images in a stable state in high-speed repetitive use. <P>SOLUTION: The particle size of a charge generating layer is made uniform by using, as a charge generating material in an electrophotographic photoreceptor, titanyl phthalocyanine crystals which have, as diffraction peaks (±0.2°) at Bragg angles 2θ for a CuKα ray (1.542 Å wavelength), at least a maximum diffraction peak at 27.2°, main peaks at 9.4°, 9.6° and 24.0°, a peak at 7.3° as a diffraction peak on the lowest angle side, and neither peak between the peak at 7.3° and the peak at 9.4° nor peak at 26.3° and which have an average size of primary particles of ≤0.25 μm. Thereby a stable electrophotographic photoreceptor can be obtained which ensures improved surface stain phenomenon and does not lower chargeability even after repeated use without losing high sensitivity. The image formation apparatus is provided with the electrophotographic photoreceptor. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus provided with a mechanism for supplying an additive to the surface of a photoreceptor. Specifically, in the repeated use of the photoreceptor in the image forming apparatus, the image forming apparatus is provided with a mechanism for supplying an additive to the surface of the photoreceptor from the outside, and the electrophotographic photoreceptor used in the image forming apparatus includes at least The present invention relates to an image forming apparatus which is an electrophotographic photosensitive member in which a charge generation layer containing a titanyl phthalocyanine crystal having a specific crystal type and a specific particle size and a charge transport layer are sequentially laminated.

  In recent years, there has been a remarkable development of information processing system machines using electrophotography. In particular, an optical printer that converts information into a digital signal and records information by light has a remarkable improvement in print quality and reliability. This digital recording technique is applied not only to printers but also to ordinary copying machines, and so-called digital copying machines have been developed. In addition, since a variety of information processing functions are added to a conventional copying machine equipped with this digital recording technology for analog copying, it is expected that its demand will increase further in the future. In addition, with the spread of personal computers and the improvement in performance, the progress of digital color printers for performing color output of images and documents is rapidly progressing.

  In recent years, printers and copiers have been demanded to increase the speed, durability, and stability of devices including colorization. In general, when a high-speed image forming apparatus is used, the amount of print used is large, and a large number of the same prints are output, but there are cases where a large number of different originals are output one by one. It is. Therefore, in the high-speed image forming apparatus, not only the high durability of the system but also the stability of the system in repeated use is very important.

  In order to realize high speed, high durability and high stability of the image forming apparatus, various devices have been made on the hardware side of the image forming apparatus, and a photoconductor suitable for this has been developed at the same time. .

  For the problem of speeding up, a photoconductor having high sensitivity and high speed response has been used. Usually, an LED of 780 nm LD or near 760 nm is used as a light source of a high-speed digital image forming apparatus. As a photoconductor (charge generating material) corresponding thereto, a diffraction peak with a Bragg angle 2θ with respect to CuKα rays (wavelength 1.542 mm) ( It is known to use a titanyl phthalocyanine crystal having a maximum diffraction peak at least 27.2 ° as ± 0.2 °. (See Patent Document 1.) This specific crystal type has a very high carrier generation function and can be effectively used as a charge generation material for a photoreceptor for a high-speed image forming apparatus. However, this crystal type has a problem that its stability as a crystal is low, and it is easy to undergo a crystal transition against mechanical stress such as dispersion, and thermal stress. Compared to the above, the sensitivity is very low, and when a part of the crystal undergoes crystal transition, a sufficient photocarrier generation function cannot be exhibited.

  Several technologies have been developed for high durability and high stability.

  As high durability technology, reduction of the amount of wear of the photoreceptor and reduction of changes in the characteristics of the photoreceptor due to electrostatic fatigue are two major problems. With respect to the former, there is a development of a surface layer having wear resistance, and a high-hardness protective layer and a surface layer (a protective layer or a charge transport layer) with reduced surface energy are being developed. Regarding the latter, development of main materials (charge generation materials and charge transport materials) that are resistant to electrostatic fatigue, and development of secondary materials (antioxidants, ultraviolet absorbers, plasticizers, and other additives) that prevent electrostatic deterioration Has been done.

  As a high stabilization technique, the point is how to suppress electrostatic fatigue as described above. In such a process in which the photosensitive member is used for a very long period without being replaced at a relatively short cycle, the lifetime of the photosensitive member becomes rate-determining, which is a cause of determining the stability of the image forming apparatus.

  However, in order to handle a photoconductor composed of an organic material equivalent to the mechanical life, it is summarized as how to maintain the photoconductor characteristics equivalent to the initial state, in other words, in the image forming apparatus. The point is how to use the electrophotographic photosensitive member while protecting it.

  Under such circumstances, the idea of supplying various additives from the outside to the surface of the photoreceptor has come out (see, for example, Patent Document 1). When using a photoconductor in an image forming apparatus for a very long time, the photoconductor surface deterioration (surface wear, surface energy increase, etc.) and photoconductor bulk deterioration (electrostatic property deterioration, etc.) From the viewpoint of quantity, it is impossible to control only with the additive added to the inside of the photoconductor, and the idea is to use it while supplying it to the surface of the photoconductor during repeated use.

  By such a technique, a very large effect was obtained for the deterioration of the surface of the photoreceptor, and for example, reduction of the amount of wear was remarkably promoted, and the surface energy of the photoreceptor can be maintained at a low state. As described above, the deterioration of the surface of the photosensitive member can be controlled in the image forming apparatus by supplying the additive to the surface of the photosensitive member from the outside. As a result, the lifetime of the photosensitive member has been controlled so far. Furthermore, “electrostatic fatigue” has changed from “wear on the photoreceptor surface” to a factor that determines the life. In particular, in a digital image forming apparatus that is the mainstream of current image forming apparatuses, negative and positive development occupies most of them, and an image defect called “dirt” has been highlighted as a big problem.

As described above, the development of the photoconductor is not sufficient for the process restrictions (requests) that occur in order to design a high-speed, highly durable, and highly stable image forming apparatus. Actually, the development of a photoreceptor for realizing image formation is not sufficient.
JP 2000-352832 A JP 2001-19871 A JP-A-6-293769 JP-A-8-110649 JP 52-36016 A JP-A-3-109406 JP 2000-206723 A JP 2001-340001 A JP-A-5-94049 JP-A-5-113688 JP-A-1-299874 (Patent No. 2512081) Japanese Patent Laid-Open No. 3-269064 (Japanese Patent No. 2854682) Japanese Patent Laid-Open No. 2-8256 (Japanese Patent Publication No. 7-91486) JP-A 64-17066 (Japanese Patent Publication No. 7-97221) Japanese Patent Laid-Open No. 11-5919 (Patent No. 3003664) Japanese Patent Laid-Open No. 3-255456 (Patent No. 3005052) Japanese Patent Laid-Open No. 61-239248 Japan Hardcopy 1989 Proceedings p. 103 1989 Moser et al., “Phthalocyanine Compounds” (1963) Moser et al., “The Phthalocyanines” (1983)

  In the image forming apparatus provided with a mechanism capable of supplying various additives to the surface of the photosensitive member for the purpose of protecting the surface of the photosensitive member, the present invention forms an image with few abnormal images even during repeated use. For this reason, as a result of various studies, it has been found that the life-determining rate of the photoconductor depends on electrostatic fatigue (especially the soiling phenomenon), and the electrophotographic photoconductor used in the image forming apparatus is at least on the conductive support. An electrophotographic photosensitive member in which a charge generation layer and a charge transport layer are sequentially laminated, and has a Bragg angle 2θ diffraction peak (± 0.2 °) with respect to CuKα rays (wavelength 1.542 mm) in the charge generation layer. It has a maximum diffraction peak at least 27.2 °, and further main peaks at 9.4 °, 9.6 °, and 24.0 °, and the lowest diffraction peak at 7.3 °. Has a peak, and There is no peak between the peak at 7.3 ° and the peak at 9.4 °, and further no peak at 26.3 °, and the average particle size of primary particles is 0.25 μm or less. It has been found that the above problems can be solved by including phthalocyanine crystals.

  It was understood that the problem of abnormal images (background stains) in the high-speed image formation described above was due to a charge leak phenomenon in the photoreceptor.

  Although the detailed reason for the effect is not clear, as for soil contamination, the maximum diffraction peak at 27.2 ° known so far is higher than that of other titanyl phthalocyanine crystals, and the titanyl phthalocyanine crystal used in the present invention has a maximum diffraction peak. It is presumed that the chemical stability is high, and the generation of scumming can be reduced because of sufficient fine particle formation.

  Thus, while effective means for controlling the process have been developed, an effective photoconductor that takes advantage of its features has not been developed, so it is not possible to apply high electric field strength for high image quality, Although there are still problems that the electrostatic latent image faithful to the writing dots on the photoconductor and the toner development faithful to the electrostatic latent image remain, the present invention has solved this problem. Lead to solution.

  Accordingly, the present invention has been made in view of the above-described problems, and an object thereof is to provide an image forming apparatus that outputs an image in a stable state without occurrence of an abnormal image when repeatedly used at high speed. To do.

  More specifically, in an image forming apparatus provided with a mechanism capable of supplying various additives to the photoreceptor surface for the purpose of protecting the photoreceptor surface, a photoreceptor containing a specific crystal type titanyl phthalocyanine crystal is used. Provides an image forming device that maintains the high sensitivity inherent to titanyl phthalocyanine by using it, and does not generate abnormal images when it is used repeatedly at high speed, and is highly durable and capable of high-speed image output in a stable state. There is to do.

  In other words, the above object is provided with at least a charging means, an exposure means, a developing means, a transfer means and an electrophotographic photosensitive member, and an additive is supplied to the surface of the photosensitive member from the outside. In the image forming apparatus having a mechanism, the electrophotographic photosensitive member is an electrophotographic photosensitive member in which at least a charge generation layer and a charge transport layer are sequentially laminated on a conductive support, and CuKα rays ( As a diffraction peak (± 0.2 °) with a Bragg angle 2θ for a wavelength of 1.542 mm, it has a maximum diffraction peak of at least 27.2 °, and further at 9.4 °, 9.6 °, and 24.0 °. It has a main peak and has a peak at 7.3 ° as the lowest diffraction peak, no peak between the 7.3 ° peak and the 9.4 ° peak. No average peak of 3 ° and no peak at 3 ° It is achieved by an image forming apparatus comprising a titanyl phthalocyanine crystal having a size of 0.25 μm or less.

  According to the first aspect of the present invention, the diffraction peak (± 0.2 °) of the Bragg angle 2θ with respect to the CuKα ray (wavelength 1.542 mm) has a maximum diffraction peak at least 27.2 °, It has major peaks at .4 °, 9.6 °, and 24.0 °, and has a peak at 7.3 ° as the lowest diffraction peak, and a peak at 7.3 ° and 9.4 °. Uses titanyl phthalocyanine crystals having no peak between the peaks of ° and no peaks at 26.3 ° and an average primary particle size of 0.25 μm or less as a charge generating material for an electrophotographic photoreceptor. By doing so, the particle size in the charge generation layer is made uniform, thereby improving the scumming phenomenon, and a stable electrophotographic photosensitive member that does not cause deterioration in chargeability even after repeated use without losing high sensitivity. Can get As a result, an image forming apparatus including the electrophotographic photosensitive member can be provided.

  The invention according to claim 2 is the invention according to claim 1, wherein the dispersion liquid has a volume average particle diameter of the titanyl phthalocyanine crystal particles of 0.3 μm or less and a standard deviation of 0.2 μm or less. The charge generation layer is coated using a dispersion liquid which has been dispersed and then filtered with a filter having an effective pore size of 3 μm or less.

  According to the second aspect of the present invention, the titanyl phthalocyanine crystal particles are dispersed until the volume average particle size is 0.3 μm or less and the standard deviation is 0.2 μm or less, and then the effective pore size is 3 μm or less. By applying the charge generation layer using the dispersion filtered through a filter, the particle size in the charge generation layer is made more uniform, thereby improving the scumming phenomenon and increasing the sensitivity. It is possible to obtain a stable electrophotographic photosensitive member that does not lose chargeability even when repeatedly used without losing, and as a result, an image forming apparatus including the electrophotographic photosensitive member can be provided.

  The invention according to claim 3 is the invention according to claim 1, wherein the titanyl phthalocyanine crystal has a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to a characteristic X-ray (wavelength 1.542Å) of CuKα. Amorphous titanyl phthalocyanine or low crystalline titanyl having a maximum diffraction peak of at least 7.0 to 7.5 °, the average particle size of primary particles having a half-width of the diffraction peak of 1 ° or more being 0.1 μm or less Crystallization of phthalocyanine is carried out with an organic solvent in the presence of water, and the titanyl phthalocyanine after crystal transformation is separated from the organic solvent by filtration before the average particle size of the primary particles after crystal transformation grows larger than 0.25 μm. It is prepared.

  According to the third aspect of the present invention, the diffraction peak (± 0.2 °) at the Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα is at least 7.0 to 7.5 °. Amorphous titanyl phthalocyanine or low crystalline titanyl phthalocyanine having a peak and a diffraction particle having a half-value width of 1 ° or more and an average primary particle size of 0.1 μm or less is mixed and stirred with an organic solvent in the presence of water. The crystal conversion is stopped before the average size of primary particles after the crystal conversion grows larger than 0.25 μm, and the titanyl phthalocyanine after the crystal conversion is fractionated and prepared by filtration The phthalocyanine crystal can provide a titanyl phthalocyanine crystal having a uniform particle size to the electrophotographic photosensitive member. An image forming apparatus that includes an electrophotographic photosensitive member, maintains high sensitivity, is highly durable, and can output a high-speed image can be provided.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the titanyl phthalocyanine crystal is synthesized using a raw material not containing a halide. .

  According to the invention described in claim 4, by using the titanyl phthalocyanine crystal synthesized by using a raw material not containing a halide, an image that has a stable chargeability and outputs a good image. A forming apparatus can be provided.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the amorphous titanyl phthalocyanine used in the crystal conversion of the titanyl phthalocyanine crystal is prepared by an acid paste method and used for cleaning. The ion-exchanged water has a physical property value between 6 and 8 and / or a specific conductivity of 8 μS / cm or less.

  According to the invention described in claim 5, the amorphous titanyl phthalocyanine used in the crystal conversion of the titanyl phthalocyanine crystal is prepared by the acid paste method, sufficiently washed with ion-exchanged water, and the ion-exchanged water after washing By using a material having a pH of 6 to 8 and / or a specific conductivity of ion-exchanged water of 8 μS / cm or less, it is possible to avoid the remaining of sulfuric acid, the photoreceptor potential is stable, and the image is stable. A forming apparatus can be provided.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the amount of the organic solvent used in the crystal conversion of the titanyl phthalocyanine crystal is 30 times or more that of amorphous titanyl phthalocyanine by weight ratio. It is characterized by being.

  According to the invention described in claim 6, when the titanyl phthalocyanine crystal is converted, the amount of the organic solvent used is 30 times (weight ratio) or more of the amorphous titanyl phthalocyanine, so that the photoreceptor potential is stabilized. An image forming apparatus with stable image quality can be provided.

  The invention according to claim 7 is the invention according to any one of claims 1 to 6, characterized in that the charge transport layer contains a polycarbonate having at least a triarylamine structure in the main chain and / or side chain. To do.

  According to the seventh aspect of the present invention, the charge transporting layer contains a polycarbonate having at least a triarylamine structure in the main chain and / or side chain, thereby being excellent in wear resistance and repeatedly used at a high speed. In this case, it is possible to provide an image forming apparatus that does not generate an abnormal image and outputs an image in a stable state.

  The invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein a protective layer is provided on the charge transport layer.

  In the invention described in claim 8, by providing a protective layer on the charge transport layer, durability can be improved, and a photosensitive member having high sensitivity and no abnormal defect can be used effectively.

The invention according to claim 9 is the invention according to claim 8, characterized in that the protective layer contains a metal oxide having a specific resistance of 10 ¹⁰ Ω · cm or more.

According to the ninth aspect of the invention, by containing a metal oxide having a specific resistance of 10 ¹⁰ Ω · cm or more in the protective layer, it provides high insulation, high thermal stability, and abrasion resistance. It has high wear resistance and is particularly useful for suppressing image blur and improving wear resistance.

  The invention according to claim 10 is the invention according to claim 8 or 9, wherein the protective layer contains a polymer charge transport material.

  According to the invention described in claim 10, the inclusion of the polymer charge transport material in the protective layer can effectively improve the durability of the photoreceptor.

  The invention according to an eleventh aspect is characterized in that, in the invention according to any one of the eighth to tenth aspects, the binder resin of the protective layer has a crosslinked structure.

  According to the invention described in claim 11, the binder resin of the protective layer having a crosslinked structure forms a three-dimensional network structure, and this network structure can improve the wear resistance and achieve the effect of high-speed charge transport. Can be obtained.

  The invention according to a twelfth aspect is characterized in that, in the invention according to the eleventh aspect, a charge transporting site is included in the structure of the binder resin having the crosslinked structure.

  According to the invention of claim 12, by having a charge transport site in the structure of the binder resin having the cross-linked structure, the wear resistance of the photoreceptor can be enhanced, and the function as a protective layer is sufficient. It becomes possible to express.

  A thirteenth aspect of the invention is characterized in that, in the invention according to any one of the first to twelfth aspects, the electroconductive support surface of the electrophotographic photosensitive member is anodized.

  According to the thirteenth aspect of the present invention, the surface defects of the electrophotographic photosensitive member are point defects (black spots) that occur when the surface of the conductive support is subjected to an anodic oxide film treatment for use in a reversal phenomenon (negative / positive phenomenon). Can be prevented.

  According to a fourteenth aspect of the present invention, in the invention according to any one of the first to thirteenth aspects, the supply of the additive is performed by a member that abuts on the photoreceptor.

  According to the fourteenth aspect of the present invention, the supply of the additive is performed by a member that contacts the photoconductor, thereby ensuring the supply of the additive to the surface of the photoconductor, and the effect of the supply of the additive Can be ensured.

  The invention according to a fifteenth aspect is the invention according to any one of the first to fourteenth aspects, wherein the additive supply member is a brush-like structural member.

  According to the fifteenth aspect of the present invention, the additive supply member is a brush-like structural member, whereby the additive can be supplied to the surface of the photoreceptor evenly.

  The invention according to a sixteenth aspect is the invention according to any one of the first to fourteenth aspects, wherein the additive supply member is an image forming developing member.

  According to the sixteenth aspect of the present invention, the supply of the additive to the image forming apparatus can be made smooth by using the additive supply member as the image forming developing member. In addition, the apparatus can be made compact.

  The invention according to claim 17 is the invention according to claim 15 or 16, characterized in that any two or more of the brush-like structural member or the developing member and the blade-like member are used in combination.

  According to the seventeenth aspect of the present invention, by using any two or more of the brush-like structural member or the developing member and the blade-like member, the additive supplied to the surface of the photoreceptor is uniformly distributed on the surface of the photoreceptor. Can be stretched and adhered.

  According to an eighteenth aspect of the present invention, in the invention according to any one of the first to fourteenth aspects, the supply of the additive is a combination of a supply from a brush-like structural member and a supply from a developing member. .

  According to the invention described in claim 18, by supplying the additive in combination with the supply from the brush-like structural member and the supply from the developing member, the supply of the additive is possible regardless of the process conditions and the output image. Can be stabilized.

  According to a nineteenth aspect of the present invention, in the invention according to any one of the first to eighteenth aspects, a contact / separation mechanism is provided on the supply member of the additive, and the photosensitive member is not charged when the charging member is not charged. It is separated from the body and is brought into contact only when charging is performed.

  According to the nineteenth aspect of the present invention, a contact / separation mechanism is provided on the additive supply member, and when the charging member is not charged to the photosensitive member, it is separated from the photosensitive member and charged only. By contacting, excessive supply of the additive can be prevented, and deterioration of the supply member and the photoreceptor surface can be prevented.

  The invention according to claim 20 is characterized in that, in the invention according to any one of claims 1 to 19, the additive is at least one selected from waxes and lubricants.

  According to the invention described in Item 20, when the additive is at least one selected from waxes and lubricants, it is possible to reliably prevent deterioration of the surface of the photoreceptor.

  The invention according to claim 21 is the invention according to claim 20, characterized in that the additive is zinc stearate.

  According to the twenty-first aspect of the present invention, since the additive is zinc stearate, deterioration of the surface of the photoreceptor can be surely prevented, and the effect is remarkably exhibited.

  According to a twenty-second aspect of the invention, in the invention according to any one of the first to twenty-first aspects, the charging member has a shield having a shape that covers at least a charging nip formed between the charging member and the photosensitive member. The relative humidity of the atmosphere in the charging nip is maintained at 50% RH or less.

  According to the twenty-second aspect of the present invention, even if the environment where the image forming apparatus is placed is a high humidity environment, it is possible to prevent image blurring.

  The invention according to claim 23 is the invention according to claim 22, wherein the relative humidity of the atmosphere in the charging nip is controlled to 50% RH or less by introducing a gas having a relative humidity of 50% RH or less into the shield. It is characterized by.

  According to the twenty-third aspect of the present invention, the effect of image blur can be ensured.

  The invention according to claim 24 is the invention according to claim 22 or 23, wherein a gas having a temperature higher than room temperature is introduced into the shield so that the relative humidity of the atmosphere in the charging nip is 50% RH or less. It is characterized by control.

  According to the twenty-fourth aspect of the present invention, the effect of image blur can be ensured.

  The invention according to claim 25 is the invention according to any one of claims 1 to 22, wherein a drum heater is installed inside the photosensitive member, and the relative humidity of the atmosphere in the charging nip is controlled to 50% RH or less. And

  According to the twenty-fifth aspect of the present invention, image blur can be prevented even if the environment where the image forming apparatus is placed is in a high humidity environment.

  According to a twenty-sixth aspect of the present invention, in the invention according to any one of the first to twenty-fifth aspects, the transfer member used in the image forming apparatus transfers the toner image formed on the photosensitive member directly to the transfer target. It is characterized by the direct transfer system.

  According to the twenty-sixth aspect of the present invention, by adopting a direct transfer system in which the transfer member directly transfers the toner image formed on the photosensitive member to the transfer target, it is possible to apply a good transfer bias. Good transfer can be performed.

  According to a twenty-seventh aspect of the invention, in the invention of the twenty-sixth aspect, the surface potential of the photoreceptor after transfer in the non-writing portion is 100 V or less as an absolute value of the polarity charged by the main charger. Features.

  According to the twenty-seventh aspect of the present invention, the surface potential of the photoreceptor after transfer in the non-writing portion is 100 V or less as the absolute value of the polarity charged by the main charger. The amount of passing charge can be reduced, and the increase in the residual potential of the photoconductor in repeated use can be reduced.

  A twenty-eighth aspect of the invention is characterized in that, in the twenty-sixth aspect of the invention, the surface potential of the photoreceptor after transfer in the non-writing portion is opposite to the polarity charged by the main charger.

  According to the twenty-eighth aspect of the invention, since the surface potential of the photoreceptor after transfer in the non-writing portion is opposite to the polarity charged by the main charger, the passing charge amount of the photoreceptor in repeated use is reduced. It is possible to reduce the increase in the residual potential of the photoreceptor in repeated use.

  According to a twenty-ninth aspect of the present invention, in the invention according to the twenty-eighth aspect, the photosensitive member surface potential after transfer in the non-writing portion is 100 V or less as an absolute value of the reverse polarity of the polarity charged by the main charger. It is characterized by being.

  According to the invention of claim 29, the surface potential of the photoreceptor after transfer in the non-writing portion is 100 V or less as the absolute value of the reverse polarity of the polarity charged by the main charger. The amount of charge passing through the photoreceptor can be reduced, and an increase in the residual potential of the photoreceptor can be reduced in repeated use.

  The invention according to claim 30 is the invention according to any one of claims 1 to 29, wherein an optical static elimination mechanism is not used.

  According to the thirty-third aspect of the present invention, it is possible to reduce an increase in the residual potential of the photoconductor in repeated use by not using the light static elimination mechanism.

  The invention according to Claim 31 is the image forming element according to any one of Claims 1 to 30, wherein the image forming apparatus comprises at least a charging means, an exposure means, a developing means, a transfer means, and an electrophotographic photosensitive member. It is characterized in that a plurality of are arranged.

  According to the thirty-first aspect of the present invention, it is possible to provide an image forming apparatus in which a plurality of image forming elements including at least a charging unit, an exposure unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member are arranged.

  A thirty-second aspect of the invention is characterized in that, in the invention according to any one of the first to thirty-first aspects, an alternating current superimposed voltage is applied to the charging means of the electrophotographic apparatus.

  According to the thirty-second aspect of the present invention, it is possible to provide an image forming apparatus that applies an AC superimposed voltage to the charging means of the electrophotographic apparatus.

  A thirty-third aspect of the present invention is the apparatus according to any one of the first to thirty-second aspects, wherein the photosensitive member and at least one unit selected from a charging unit, an exposing unit, a developing unit, and a cleaning unit are integrated. It is equipped with a cartridge that is detachable from the main body.

  According to the thirty-third aspect of the present invention, the apparatus main body in which the photosensitive member and at least one unit selected from the charging unit, the exposure unit, the developing unit, and the cleaning unit are integrated and the removable cartridge are mounted. An image forming apparatus can be provided.

  According to the present invention, it is an image forming apparatus that outputs an image at a very high speed, and an image forming apparatus that outputs a stable and high-resolution image without occurrence of an abnormal image when repeatedly used at a high speed can be provided. .

  Specifically, in an image forming apparatus having a mechanism for supplying an additive to the surface of a photoconductor to perform high-speed image formation with high stability, a titanyl phthalocyanine crystal having a specific crystal type and a specific particle size is used as the photoconductor for this. By using a photoconductor containing the above, it is possible to provide an image forming apparatus that maintains the high sensitivity inherent to titanyl phthalocyanine, is highly durable, and can output a high-speed image.

  First, the image forming apparatus of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram for explaining an image forming apparatus of the present invention, and modifications as described below also belong to the category of the present invention.

  In FIG. 1, the photoreceptor (1) is provided with a photosensitive layer including at least a charge generation layer and a charge transport layer on a conductive support, and the charge generation layer has a Bragg angle with respect to CuKα rays (wavelength 1.542 mm). As the 2θ diffraction peak (± 0.2 °), it has a maximum diffraction peak at least 27.2 °, and further has major peaks at 9.4 °, 9.6 °, 24.0 °, and The lowest diffraction peak has a peak at 7.3 °, and no peak between the peak at 7.3 ° and the peak at 9.4 °, and further at 26.3 °. It contains a titanyl phthalocyanine crystal having no peak and an average primary particle size of 0.25 μm or less. The photosensitive member (1) has a drum shape, but may be a sheet or an endless belt.

  The apparatus shown in FIG. 1 has a mechanism for supplying various additives to the surface of the photoreceptor. The mechanism for supplying the additive may be arranged at any position in the image forming apparatus. However, in consideration of image formation during one round, an area where there is no possibility of disturbing the toner image (the surface of the photoconductor is transferred). It is desirable to be disposed at a position after passing through the member. In addition, when supplying a solid state substance, in order to uniformly supply the surface of the photoconductor, it is arranged in front of the cleaning member so that the surface of the photoconductor is made uniform by the cleaning member. It can be said that it is supplied evenly and desirable. Furthermore, a mechanism in which the cleaning member and the supply member are in service is also an effective method for making the apparatus compact.

  As a mechanism for supplying the additive to the surface of the photosensitive member from the outside, a method of pressing the solidified additive (42) directly on the surface of the photosensitive member (40) as shown in FIG. A method of transferring the additive from the member in contact with (40) to the surface of the photoreceptor (40) is desirable. For example, a method of supplying the photosensitive member surface via a member such as a brush-like structural member (41; preferably an elastic body), a blade-like structural member (43), or a roller-like member (desirably an elastic body) may be mentioned. . Among these, considering the mechanical stress on the surface of the photoreceptor (40), the brush-like structural member (41) is used favorably. For example, the additive (42) solidified is brought into contact with the brush-like structural member (41), and the brush-like structural member (41) is rotated to scrape the additive (42) little by little, and this is photosensitive. It is rubbed against the surface of the body (40). At this time, the additive (42) adheres to the surface of the photoreceptor (40), but depending on the type of the additive (42), it may adhere to the surface of the photoreceptor (40) in a powdery state. In such a case, it is desirable to use the blade-like structural member (43) in combination after the attachment with the brush-like structural member (41), so that the effect can be expected more (FIG. 12). As shown in FIG. 2, it is preferable that at least the brush-like structural member (41) is located upstream of the charging member (45). Further, the brush-like structural member (41) and the blade-like structural member (43) can be used in combination with a cleaning member for cleaning the transfer residual toner.

  It is also an effective means to supply the additive using the developing member (44). In this case, either a method of mixing an additive with the developer or a method of containing the toner in the developer is used. In this case as well, depending on the type of additive, it may adhere to the surface of the photoreceptor in a powdery state, and it is desirable to stretch by using a blade-like structural member in combination, and more effects are expected. it can.

  There are advantages and disadvantages in both the supply by the brush-like structural member (41) and the supply by the developing member (44). When the brush-like structural member (41) is used, the function of uniformly adhering the additive (42) to the surface of the photoreceptor (40) can be achieved relatively easily, but the amount of the additive (42) used. In the case where there are many, there is a demerit that the additive (42) has to be replenished somewhere with repeated use of the image forming apparatus. On the other hand, in the case of supply by the developing member (44), it is possible to replenish the additive by a method of replenishing the developer and toner, and there is no problem with replenishment, but the image density of the output image is extremely low Alternatively, in the case of a document with a very uneven printing section, there is a disadvantage that it is difficult to uniformly supply the entire surface of the photosensitive member.

  The combined use of both mechanisms is extremely effective in taking advantage of both advantages and complementing the disadvantages.

  Further, the mechanism for supplying the additive may have a contact / separation mechanism with respect to the surface of the photoreceptor. By having such a mechanism, it is not necessary to always contact the surface of the photoconductor, and excessive supply of additives to the surface of the photoconductor and deterioration of the supply member or the surface of the photoconductor can be prevented.

  The additive used in the present invention is a substance that is supplied to the photoreceptor (40) and adheres uniformly to the surface, and improves the function of the photoreceptor in repeated use, protects the photoreceptor surface, etc. Any device having a function can be used. The additive only needs to function to have at least an additional function on the surface of the photoconductor, and it may be sufficient to perform the function for one circumference of the photoconductor. Therefore, even if it is removed from the surface every round by, for example, a cleaning member, it does not matter. For this reason, it is sufficient that the additive is extremely thin and adheres to the surface of the photoreceptor, and in this respect, a stretchable material can be used favorably. For example, materials such as waxes and lubricants can be used satisfactorily.

  The waxes used in the present invention are preferably ester-based or olefin-based. The ester wax has an ester bond, and examples thereof include natural waxes such as carnauba wax, candelilla wax and rice wax, and montan wax. Examples of the olefin wax include synthetic waxes such as polyethylene wax and polypropylene wax.

  In addition, as the lubricant, various fluorine-containing resins such as PTFE, PFA, and PVDF, silicone resin, polyolefin resin, zinc stearate, zinc laurate, zinc myristate, calcium stearate, aluminum stearate, and other fatty acid metal salts, etc. Can be mentioned. Of these, zinc stearate is most preferable.

  Further, an antioxidant or an ultraviolet absorber can be used as an additive in order to protect it from an oxidizing gas or harmful light from the surface of the photoreceptor. These can use a commercially available material arbitrarily. Antioxidants and the like cause side effects such as an increase in residual potential when added in a large amount to the photoreceptor, and the amount of addition is limited. However, as in the present invention, the antioxidant is externally added to the photoreceptor surface. In some cases, all unnecessary amounts are removed by a blade or the like, so that there is no adverse effect.

  As the charging member (3), a scorotron charging member is preferably used for the photoreceptor. By this charging member, an electric field strength of 30 V / μm or more is applied to the photoreceptor. The higher the electric field strength applied to the photoreceptor, the better the dot reproducibility, but it may cause problems with dielectric breakdown of the photoreceptor and carrier adhesion during development. The upper limit is approximately 60 V / μm or less, more Preferably, it is 50 V / μm or less.

  The image exposure unit (5) uses a light source capable of ensuring high brightness and capable of writing at a resolution of 600 dpi or more, such as a light emitting diode (LED), a semiconductor laser (LD), and electroluminescence (EL). . Depending on the resolution of the light source (writing light), the resolution of the formed electrostatic latent image, and thus the toner image, is determined. The higher the resolution, the clearer the image. However, if writing is performed at a higher resolution, writing takes longer, so writing with one writing light source is limited by the drum linear speed (process speed). Therefore, when there is one writing light source, a resolution of about 1200 dpi is the upper limit. When there are a plurality of writing light sources, each of them only has to bear the writing area, and the upper limit is substantially “1200 dpi × number of writing light sources”. The writing light source here refers to one LD element or one LED element. For example, LEDs arranged in an array are handled as a plurality of light sources.

  Among these light sources, light emitting diodes and semiconductor lasers have high irradiation energy and have long wavelength light of 600 to 800 nm. Therefore, the specific crystal type phthalocyanine pigment which is a charge generation material used in the present invention has high sensitivity. Used well from showing.

  The developing unit (6) can handle both normal development and reversal development depending on the charging polarity of the toner used. When toner having a polarity opposite to the charged polarity of the photoreceptor is used, normal development is used. When toner having the same polarity is used, the electrostatic latent image is developed by reversal development. Depending on the light source used in the previous image exposure unit, in the case of a digital light source used in recent years, there is generally a reversal development method in which toner development is performed on the writing portion in response to a low image area ratio. This is advantageous in view of the life of the light source. There are two methods, a one-component method in which development is performed using only toner and a two-component method in which a two-component developer composed of toner and carrier is used.

  The transfer charger (10) may be a transfer belt or a transfer roller, but it is desirable to use a contact type such as a transfer belt or transfer roller that generates less ozone. In particular, a direct transfer method that directly transfers a toner image formed on the surface of the photosensitive member to a transfer target is favorably used. As a voltage / current application method at the time of transfer, either a constant voltage method or a constant current method is used. Although a method can also be used, a constant current method that can keep the transfer charge amount constant and has excellent stability is more desirable.

  Further, the toner image formed on the photoconductor is transferred onto the transfer paper to become an image on the transfer paper. At this time, there are two methods. One is a method of directly transferring the toner image developed on the surface of the photosensitive member as shown in FIG. 1 to the transfer paper, and the other is that the toner image is once transferred from the photosensitive member to the intermediate transfer member, and this is transferred to the transfer paper. It is the method of transferring to. Either case can be used in the present invention. In particular, a direct transfer system that directly transfers a toner image formed on the surface of the photoreceptor to a transfer target (such as paper to be output) is preferably used.

  As such a transfer member, a known member can be used as long as the structure of the present invention can be satisfied.

  At this time, the surface potential of the photoreceptor after transfer has a great influence on the electrostatic fatigue of the photoreceptor in repeated use. That is, the electrostatic fatigue of the photoreceptor is greatly influenced by the amount of charge passing through the photoreceptor. This passing charge amount corresponds to the amount of charge flowing in the film thickness direction of the photoreceptor. As an operation in the image forming apparatus of the photoconductor, the main charger is charged to a desired charging potential (in most cases, negatively charged), and optical writing is performed based on an input signal corresponding to the original. At this time, photocarriers are generated in the portion where writing is performed, and the surface charge is neutralized (potential decay). At this time, the amount of charge depending on the amount of generated photocarriers flows in the direction of the photoreceptor film thickness.

  On the other hand, the area where the optical writing is not performed (non-writing portion) proceeds to the charge removal process through the development process and the transfer process (a cleaning process is performed before that if necessary). Here, when the surface potential of the photoconductor is close to the potential applied by main charging (excluding dark decay), the amount of charge is almost the same as that in the area where optical writing is performed. Will flow into. In general, since the current document has a low writing rate, this method means that the current passing through the photoconductor in repeated use is mostly current flowing in the static elimination process (the writing rate is 10%). Then, the current flowing in the static elimination process occupies 90% of the total).

  This passing charge greatly affects the electrostatic characteristics of the photoconductor, for example, causing deterioration of the material constituting the photoconductor. As a result, the residual potential of the photosensitive member is raised, depending on the amount of passing charge. When the residual potential of the photosensitive member is increased, the image density is lowered in the negative / positive development used in the present invention, which is a serious problem. Therefore, there is a problem of how to reduce the passing charge amount of the photoconductor in order to increase the lifetime (high durability) of the photoconductor in the image forming apparatus.

  On the other hand, there is a way of thinking that the photostatic discharge is not performed, but if the main charger is not sufficiently charged, the charging cannot be stabilized and a problem such as an afterimage may occur.

  The passing charge of the photoconductor is generated by the movement of the generated optical carrier by light irradiation by the electric potential (the electric field generated thereby) charged on the surface of the photoconductor. Therefore, if the photoreceptor surface potential can be attenuated by means other than light, the amount of charge passing per rotation of the photoreceptor (one cycle of image formation) can be reduced.

  For this purpose, it is effective to adjust the charge passing through the photosensitive member by adjusting the transfer bias in the transfer process. That is, a non-writing portion that is charged by main charging and does not perform writing enters the transfer process in a state close to the charged potential except for the dark attenuation amount. At this time, the absolute value on the polarity side charged by the main charger is reduced to 100 V or less, so that almost no photocarrier is generated even when the subsequent charge removal process is entered, and no passing charge is generated. This value is preferably closer to 0V.

  Furthermore, by adjusting the transfer bias, by applying a transfer bias so that the surface potential of the photosensitive member is charged to a polarity opposite to the charging polarity applied by the main charging, it is more preferable because no optical carrier is generated. . However, under transfer conditions that charge to a reverse polarity, there may be cases where a large amount of transfer dust occurs or the main charge of the next image forming process (cycle) cannot catch up. In that case, since a problem such as an afterimage may occur, the absolute value of the reverse polarity is preferably 100 V or less.

  Further, the toner developed on the photosensitive member (1) by the developing unit (6) is transferred to the transfer paper (7). If toner remaining on the photosensitive member (1) is generated, a fur brush ( 14) and the blade (15) to remove from the photoreceptor. Cleaning may be performed only with a cleaning brush, and a known brush such as a fur brush or a mag fur brush is used as the cleaning brush.

  Use light sources such as fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light-emitting diodes (LEDs), semiconductor lasers (LDs), and electroluminescence (ELs) as light sources such as static elimination lamps (2). Can do. 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.

  Such a light source or the like irradiates the photosensitive member with light by providing a transfer process, a static elimination process, a cleaning process, or a pre-exposure process using light irradiation in addition to the process shown in FIG.

  This neutralization mechanism can be omitted when the AC component is superposed and used in the previous charging method, or when the residual potential of the photoreceptor is small. Further, instead of optical static elimination, an electrostatic static elimination mechanism (for example, a static elimination brush with a reverse bias applied or grounded) can be used. As described above, a document having a small writing rate has a large effect of light neutralization, and it is preferable not to use light neutralization as long as there is no influence of afterimage or the like in the next image forming cycle.

  In the figure, 8 is a registration roller, 11 is a separation charger, and 12 is a separation claw.

  When an image is formed by providing a mechanism for supplying the additive (42) to the surface of the photoconductor (40) as described above, if the environment where the image forming apparatus is placed is too humid, In rare cases, side effects may occur. The most effective way to avoid this is to reduce the humidity of the atmosphere in the charging nip. Specifically, if it is 50% RH or less, it can be effectively avoided. Two methods for easily enabling this will be described below.

  One of the image forming apparatuses includes a charging member (45) having a shield shaped to cover a charging nip formed between the charging member (45) and the photosensitive member (40). Is maintained at 50% RH or less. An example of the configuration of the charging member that can achieve such a state is shown in FIG.

  A shield (48) is disposed so as to cover the charging roller (47) adjacent to the photoconductor (46), and a portion (49) for introducing gas is attached to the upper part of the shield. The shield (48) may be either in contact with the photoreceptor (46) or not as long as it can maintain a low humidity state. In the case of contact, it is desirable that at least the contact portion with the photoreceptor (46) is made of an elastic body such as rubber or sponge so that the shield (48) does not wear the surface of the photoreceptor (46). In the case of no contact, it is necessary to narrow the gap between the shield (48) and the photoconductor (46) as much as possible so that the low humidity state can be maintained, and set the flow rate of the introduced gas to be large. Such a shield (48), as shown in FIG. 3, is required to cover at least the charging member (47) and the charging nip portion, but the electrophotographic element (at least the photosensitive member (46), the charging member (47), One unit having the developing member) may be entirely covered. However, in this case, the amount of gas to be introduced becomes large, so it is necessary to make it as compact as possible. In such a state, the atmospheric humidity in the charging nip is reduced to 50% RH or less by introducing a gas having a relative humidity of 50% RH or less or introducing a gas having a temperature higher than room temperature.

  Another method is to install a drum heater inside the photoconductor (46), and when the atmospheric humidity is higher than 50% RH, operate the drum heater to reduce the relative humidity of the atmosphere in the charging nip. Is. In this case, the charging nip is effective even with an open type, but the structure covered with a shield is more effective and the temperature of the drum heater does not need to increase so much. This is an effective means because it has little adverse effect on image formation and power consumption in the drum heater.

  FIG. 4 is a schematic diagram for explaining the tandem-type full-color image forming apparatus of the present invention, and the following modifications also belong to the category of the present invention. The image forming apparatus of FIG. 4 is provided with a mechanism for supplying an additive to the surface of the photoreceptor.

  In FIG. 4, reference numerals (16Y), (16M), (16C), and (16K) are drum-shaped photoconductors, and the photoconductor (1) has at least a charge generation layer and a charge transport layer on a conductive support. The charge generation layer has a maximum diffraction peak at 27.2 ° as a Bragg angle 2θ diffraction peak (± 0.2 °) with respect to CuKα rays (wavelength 1.542 mm). Further, it has major peaks at 9.4 °, 9.6 °, and 24.0 °, and has a peak at 7.3 ° as the diffraction peak at the lowest angle side, and the above-mentioned 7.3 ° And no titer between the peak of 9.4 ° and the peak of 9.4 °, and further has no peak at 26.3 °, and contains a titanyl phthalocyanine crystal having an average primary particle size of 0.25 μm or less. Become.

  In the image forming apparatus shown in FIG. 4, each of the image forming elements (25Y), (25M), (25C), (25K) is surrounded by the respective photoreceptors (16Y), (16M), (16C), (16K). Is provided with mechanisms (27Y), (27M), (27C), and (27K) that can supply various additives to the surface of the photoreceptor.

  The photoconductors (16Y), (16M), (16C), and (16K) rotate in the direction of the arrow in the figure, and around them, at least in the order of rotation, the scorotron charging members (17Y), (17M), (17C) , (17K), developing members (19Y), (19M), (19C), (19K), and cleaning members (20Y), (20M), (20C), (20K) are arranged. The charging members (17Y), (17M), (17C), and (17K) are charging members that constitute a charging device for uniformly charging the surface of the photoreceptor. From the photosensitive member surface side between the charging members (17Y), (17M), (17C), (17K) and the developing members (19Y), (19M), (19C), (19K), from an exposure member (not shown) Laser beams (18Y), (18M), (18C), and (18K) are irradiated so that an electrostatic latent image is formed on the photoconductors (16Y), (16M), (16C), and (16K). It has become. Then, the four image forming elements (25Y), (25M), (25C), and (25K) centering on such photoconductors (16Y), (16M), (16C), and (16K) serve as transfer materials. They are juxtaposed along the transfer conveyance belt (22) which is a conveyance means. The transfer / conveying belt (22) includes developing members (19Y), (19M), (19C), (19K) and cleaning members (20Y) of the image forming units (25Y), (25M), (25C), (25K). , (20M), (20C), and (20K) are in contact with the photosensitive member (16Y), (16M), (16C), and (16K), and contact the back side of the photosensitive member side of the transfer conveyance belt (22). Transfer brushes (21Y), (21M), (21C), and (21K) for applying a transfer bias are arranged on the surface (back surface). Each of the image forming elements (25Y), (25M), (25C), and (25K) is different in the color of the toner inside the developing device, and the others are the same in configuration.

  In the full-color image forming apparatus having the configuration shown in FIG. 4, the image forming operation is performed as follows. First, in each of the image forming elements (25Y), (25M), (25C), and (25K), an electrostatic latent image is formed on the photoconductors (16Y), (16M), (16C), and (16K). It has become. Then, such photoconductors (16Y), (16M), (16C), and (16K) rotate and are charged by the charging members (17Y), (17M), (17C), and (17K).

  Next, writing is performed at a resolution of 600 dpi or more (preferably 1200 dpi or more) by laser light (18Y), (18M), (18C), or (18K) at an exposure unit (not shown) disposed outside the photoreceptor. Thus, an electrostatic latent image corresponding to each color image to be created is formed. Also in this case, 1200 dpi writing is generally the upper limit for one writing light source.

  Next, the latent image is developed by the developing members (19Y), (19M), (19C), and (19K) to form a toner image. Development members (19Y), (19M), (19C), and (19K) are development members that perform development with toners of Y (yellow), M (magenta), C (cyan), and K (black), respectively. The toner images of the respective colors formed on the two photoconductors (16Y), (16M), (16C), and (16K) are superimposed on the transfer paper. The transfer paper (26) is fed out from the tray by a paper feeding roller (not shown), temporarily stopped by a pair of registration rollers (23), and transferred and conveyed (22) in synchronization with the image formation on the photosensitive member. ). The transfer paper (26) held on the transfer conveyance belt (22) is conveyed, and each color is in contact with each photoconductor (16Y), (16M), (16C), (16K) (transfer section). The toner image is transferred.

  The toner image on the photoconductor includes transfer bias applied to the transfer brushes (21Y), (21M), (21C), and (21K) and the photoconductors (16Y), (16M), (16C), and (16K). The image is transferred onto the transfer paper (26) by an electric field formed from the potential difference. Then, the recording paper (26) on which the four color toner images are passed through the four transfer sections is conveyed to the fixing device (24), where the toner is fixed, and is discharged to a paper discharge section (not shown).

  Further, residual toner remaining on each of the photoconductors (16Y), (16M), (16C), and (16K) without being transferred by the transfer unit is removed from the cleaning devices (20Y), (20M), (20C), ( 20K).

  Subsequently, excess residual charges on the photosensitive member are removed by the charge eliminating members (27Y), (27M), (27C), and (27K). Thereafter, the charging member is uniformly charged again, and the next image formation is performed.

  In the example of FIG. 4, the image forming elements are arranged in the order of Y (yellow), M (magenta), C (cyan), 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 creating a black-only document, it is particularly effective to use the present invention to provide a mechanism that stops image forming elements other than black ((25Y), (25M), (25C)). .

  Also in this case, as described above, the photoreceptor surface potential after transfer is controlled to 100 V or less, preferably reverse polarity, more preferably 100 V or less, on the main charging polarity side, thereby repeating the photoreceptor. It is possible and effective to reduce the increase in residual potential during use.

  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. The 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, a charge eliminating unit, and the like. There are many shapes and the like of the process cartridge, but a general example is shown in FIG. The process cartridge shown in FIG. 5 has a mechanism (109) that can supply various additives to the surface of the photoreceptor at any position around the photoreceptor.

  The photoreceptor (101) is provided with a photosensitive layer including at least a charge generation layer and a charge transport layer on a conductive support, and the charge generation layer has a diffraction peak with a Bragg angle 2θ with respect to CuKα rays (wavelength 1.542 mm). (± 0.2 °) having a maximum diffraction peak at least 27.2 °, and further having major peaks at 9.4 °, 9.6 °, and 24.0 °, and the lowest angle side The diffraction peak of 7.3 ° has a peak at 7.3 °, has no peak between the 7.3 ° peak and the 9.4 ° peak, and further has a peak at 26.3 °. First, it contains titanyl phthalocyanine crystals having an average primary particle size of 0.25 μm or less.

  As described above, a light source capable of writing at a resolution of 600 dpi or more (preferably 1200 dpi or more) is used for the image exposure unit (103). In FIG. 5, 104 is a developing unit, 105 is a transfer member, 106 Is a transfer means, 107 is a cleaning means, and 108 is a charge eliminating means.

  Hereinafter, the electrophotographic photosensitive member used in the image forming apparatus of the present invention will be described in detail. The electrophotographic photosensitive member used in the present invention is an electrophotographic photosensitive member in which at least a charge generation layer and a charge transport layer are formed on a conductive support, and CuKα rays (wavelength 1.. As a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to 542 Å), it has a maximum diffraction peak at least 27.2 °, and further main peaks at 9.4 °, 9.6 °, and 24.0 ° And has a peak at 7.3 ° as the lowest angle diffraction peak, and no peak between the 7.3 ° peak and the 9.4 ° peak, and It contains titanyl phthalocyanine crystals having no peak at 26.3 ° and an average primary particle size of 0.25 μm or less.

  Although this crystal type is described in Patent Document 2, by using this titanyl phthalocyanine crystal, a stable electrophotographic photosensitive member that does not cause deterioration in chargeability even after repeated use without losing high sensitivity. Can be obtained.

  Patent Document 2 discloses a charge generating material used in the present invention, a photoconductor using the same, an electrophotographic apparatus, and the like. However, when used in a system that requires a very long life and high stability of the photoreceptor, such as having a mechanism for supplying various additives to the photoreceptor surface around the photoreceptor, Electrostatic fatigue has become the rate-determining rather than photoconductor wear. In such an image forming apparatus, it is not possible to solve the problem specific to negative / positive development such as smudge.

  The present inventors have found that non-uniformity in the charge generation layer is a major cause for the soiling phenomenon. In order to solve this problem, it was understood that control of the particle size in the charge generation layer is essential, and it is important to align the particle size in a smaller direction. As a result, as described later, the particle size is reduced at the time of synthesis, or coarse particles are removed at the time of filtration after dispersion, thereby succeeding in controlling the particle size and corresponding to the image forming apparatus as described above. We were able to develop photoconductor technology that can be used.

  Further, Patent Document 2 has no description about the particle size and no description of the technology for controlling it, and the particle size has not been optimized. In the present invention, a more optimal image forming apparatus is constructed by using a photoconductor containing a specific crystal type titanyl phthalocyanine having a controlled particle size and optimizing the process conditions of the image forming apparatus.

  As a method for synthesizing a titanyl phthalocyanine crystal, as described in Patent Document 3, a method in which titanium halide is not used as a raw material is favorably used. The biggest merit of this method is that the synthesized titanyl phthalocyanine crystal is free of halogenation. When the titanyl phthalocyanine crystal contains a halogenated titanyl phthalocyanine crystal as an impurity, there are many adverse effects such as a decrease in photosensitivity and a decrease in chargeability in the electrostatic characteristics of a photoreceptor using the crystal (see Non-Patent Document 1). reference.). Also in the present invention, the halogenated free titanyl phthalocyanine crystal as described in Patent Document 2 is mainly used, and these materials are effectively used.

  In order to synthesize a halogenated free titanyl phthalocyanine, it is necessary not to use a halogenated material as a raw material in the synthesis of titanyl phthalocyanine. Specifically, the method described later is used.

  First, a method for synthesizing a titanyl phthalocyanine crystal having a specific crystal type used in the present invention will be described.

  First, a method for synthesizing a crude product of titanyl phthalocyanine crystal will be described. Methods for synthesizing phthalocyanines have been known for a long time, and are described in Non-Patent Document 2, Non-Patent Document 3, Patent Document 3, and the like.

  For example, as a first method, a mixture of phthalic anhydrides, metal or metal halide and urea is heated in the presence or absence of a high boiling point solvent. In this case, a catalyst such as ammonium molybdate is used in combination as necessary. As a second method, phthalonitriles and metal halides are heated in the presence or absence of a high boiling point solvent. This method is used for phthalocyanines that cannot be produced by the first method, such as aluminum phthalocyanines, indium phthalocyanines, oxovanadium phthalocyanines, oxotitanium phthalocyanines, zirconium phthalocyanines, and the like. The third method is to first react phthalic anhydride or phthalonitrile with ammonia to produce an intermediate such as 1,3-diiminoisoindoline, and then react with a metal halide in a high boiling solvent. It is a method to make it. The fourth method is a method in which phthalonitriles and a metal alkoxide are reacted in the presence of urea or the like. In particular, the fourth method does not cause chlorination (halogenation) to the benzene ring, and is a very useful method as a method for synthesizing an electrophotographic material, and is used extremely effectively in the present invention.

  Next, a method for synthesizing amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) will be described. In this method, phthalocyanines are dissolved in sulfuric acid, diluted with water and reprecipitated, and an acid paste method or an acid slurry method can be used.

  As a specific method, the above synthetic crude product is dissolved in 10 to 50 times the amount of concentrated sulfuric acid, and if necessary, insoluble matters are removed by filtration or the like, and this is sufficiently cooled to 10 to 50 times the amount of sulfuric acid. Slowly throw it into water or ice water to reprecipitate titanyl phthalocyanine. The precipitated titanyl phthalocyanine is filtered, washed with ion-exchanged water and filtered, and this operation is sufficiently repeated until the filtrate becomes neutral. Finally, after washing with clean ion-exchanged water, filtration is performed to obtain a water paste having a solid concentration of about 5 to 15 wt%.

  At this time, it is important to thoroughly wash with ion-exchanged water so as not to leave concentrated sulfuric acid as much as possible. Specifically, it is preferable that the ion-exchanged water after washing exhibits the following physical property values. That is, if the residual amount of sulfuric acid is expressed quantitatively, it can be expressed by the pH and specific conductivity of ion-exchanged water after washing. When expressed in terms of pH, the pH is preferably in the range of 6-8. Within this range, it can be determined that the remaining amount of sulfuric acid does not affect the photoreceptor characteristics. This pH value can be easily measured with a commercially available pH meter. In terms of specific conductivity, it is desirably 8 μS / cm or less (preferably 5 μS / cm or less, more preferably 3 μS / cm or less). Within this range, it can be determined that the remaining amount of sulfuric acid does not affect the photoreceptor characteristics. This specific conductivity can be measured with a commercially available electric conductivity meter. The lower limit of the specific conductivity is the specific conductivity of the ion exchange water used for cleaning. In any measurement, in the range deviating from the above range, the remaining amount of sulfuric acid is large, and the chargeability of the photoreceptor is lowered or the photosensitivity is deteriorated.

  What was produced in this way was the amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) used in the present invention. At this time, the amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) is at least 7.0 to 7 as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 波長) of CuKα. It is preferable to have a maximum diffraction peak at 5 °. In particular, the half width of the diffraction peak is more preferably 1 ° or more. Further, the average particle size of the primary particles is preferably 0.1 μm or less.

  Next, a crystal conversion method will be described.

  Crystal transformation is performed by using the amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) as a diffraction peak (± 0.2 °) at a Bragg angle 2θ with respect to the characteristic X-ray of CuKα (wavelength 1.542Å) at least 27.2 °. And has a major peak at 9.4 °, 9.6 °, and 24.0 °, and a peak at 7.3 ° as the lowest diffraction peak, And, it is a step of converting to a titanyl phthalocyanine crystal having no peak between the peak at 7.3 ° and the peak at 9.4 ° and not having a peak at 26.3 °.

  As a specific method, the crystalline form is obtained by mixing and stirring together with an organic solvent in the presence of water without drying the amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine). .

  At this time, any organic solvent can be used as long as the desired crystal form can be obtained. In particular, tetrahydrofuran, toluene, methylene chloride, carbon disulfide, orthodichlorobenzene, 1,1, Good results are obtained when one selected from 2-trichloroethane is selected. These organic solvents are preferably used alone, but two or more of these organic solvents may be mixed or used in combination with other solvents. It is desirable that the amount of the organic solvent used for crystal conversion is 10 times or more, preferably 30 times or more the weight of amorphous titanyl phthalocyanine. This is because crystal conversion is caused quickly and sufficiently, and an effect of sufficiently removing impurities contained in amorphous titanyl phthalocyanine is exhibited. The amorphous titanyl phthalocyanine used here is prepared by the acid paste method, but it is desirable to use one obtained by sufficiently washing sulfuric acid as described above. When crystal conversion is performed under conditions where sulfuric acid remains, sulfate ions remain in the crystal particles, and the completed crystals cannot be completely removed even by an operation such as washing with water. When sulfate ions remain, preferable results cannot be obtained, such as a decrease in sensitivity and a decrease in chargeability of the photoreceptor. For example, Patent Document 4 (Comparative Example) describes a method in which titanyl phthalocyanine dissolved in sulfuric acid is added to an organic solvent together with ion-exchanged water to perform crystal conversion. At this time, a crystal similar to the X-ray diffraction spectrum of the titanyl phthalocyanine crystal obtained in the present invention can be obtained, but the sulfate ion concentration in titanyl phthalocyanine is high and the light attenuation characteristic (photosensitivity) is poor. However, the method for producing titanyl phthalocyanine of the present invention is not good. The reason for this is as described above.

  The crystal conversion method described above is a crystal conversion method according to Patent Document 2. On the other hand, in the charge generating material contained in the photoreceptor used in the electrophotographic apparatus of the present invention, the effect is achieved by making the particle size of the titanyl phthalocyanine crystal finer (0.25 μm or less). . The following describes a method for synthesizing titanyl phthalocyanine particle size smaller than the synthesis step.

  In order to make the particle size of the titanyl phthalocyanine crystal finer, the present inventors have observed that the above-mentioned amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) has a primary particle size of 0.1 μm or less (its Although most of them are about 0.01 to 0.05 μm) (see FIG. 6), it has been found that the crystals are converted with crystal growth during the crystal conversion. Usually, in this type of crystal conversion, a sufficient crystal conversion time is ensured due to fear of remaining of the raw material, and after the crystal conversion is sufficiently performed, filtration is performed to obtain a titanyl phthalocyanine crystal having a desired crystal type. Is what you get. For this reason, even though a raw material having sufficiently small primary particles is used as a raw material, a crystal having a large primary particle (approximately 0.3 to 0.5 μm) is obtained as a crystal after crystal conversion. Yes (see FIG. 7).

  The scale bars in the figure are all 0.2 μm.

  When dispersing the titanyl phthalocyanine crystal produced as shown in FIG. 7, in order to make the particle size after dispersion small (0.25 μm or less), dispersion is performed by giving a strong share, and further necessary. In response to this, dispersion is performed by giving strong energy to pulverize the primary particles. As a result, as described above, there is a possibility that a part of the particles may be transferred to a crystal type which is not a desired crystal type.

  In this regard, by controlling the primary particle size of the titanyl phthalocyanine crystal from the synthesis stage to obtain a crystal having a small size, a method for solving this problem is possible and it is effectively used in the present invention. Specifically, the range in which crystal growth hardly occurs during crystal conversion (the range in which the size of the amorphous titanyl phthalocyanine particles observed in FIG. 7 is insignificantly small after crystal conversion, approximately 0.25 μm or less. ) Is to obtain a titanyl phthalocyanine crystal having a primary particle size as small as possible by determining when the crystal conversion is completed. The particle size after crystal conversion increases in proportion to the crystal conversion time. For this reason, as described above, it is important to increase the efficiency of crystal conversion and complete it in a short time. There are several important points for this.

  One is to select an appropriate crystal conversion solvent as described above to increase the crystal conversion efficiency. The other is to use strong agitation to sufficiently bring the solvent into contact with the titanyl phthalocyanine water paste (raw material prepared as described above: amorphous titanyl phthalocyanine) in order to complete the crystal conversion in a short time. Specifically, it is possible to achieve crystal conversion in a short time by using a propeller with a very strong stirring force or using a strong stirring (dispersing) means such as a homogenizer (homomixer). is there. Under these conditions, it is possible to obtain a titanyl phthalocyanine crystal in a state in which crystal conversion is sufficiently performed and crystal growth does not occur without remaining raw materials. Also in this case, optimization of the amount of organic solvent used for crystal conversion is an effective means. Specifically, it is desirable to use 10 times or more, preferably 30 times or more of the organic solvent with respect to the solid content of the amorphous titanyl phthalocyanine. Thereby, crystal conversion in a short time can be ensured and impurities contained in the amorphous titanyl phthalocyanine can be surely removed.

  In addition, since the crystal grain size and the crystal conversion time are in a proportional relationship as described above, a method of immediately stopping the reaction when a predetermined reaction (crystal conversion) is completed is also an effective means. As the above-mentioned means, it is possible to immediately add a large amount of a solvent in which crystal conversion hardly occurs after crystal conversion as described above. Examples of the solvent that hardly causes crystal transformation include alcohol-based and ester-based solvents. Crystal conversion can be stopped by adding about 10 times these solvents to the crystal conversion solvent.

  The smaller the primary particle size produced in this way, the better the results for the problem of the photoreceptor, but the next step for pigment preparation (pigment filtration step), dispersion in dispersion In consideration of stability, side effects may occur even if it is too small. That is, when the primary particles are very fine, there arises a problem that the filtration time becomes very long in the step of filtering the primary particles. In addition, when the primary particles are too fine, the surface area of the pigment particles in the dispersion increases, and the possibility of reaggregation of the particles increases. Accordingly, the appropriate particle size of the pigment particles is in the range of about 0.05 μm to 0.2 μm.

  FIG. 8 shows a TEM image of a titanyl phthalocyanine crystal when crystal conversion is performed in a short time. The scale bar in the figure is 0.2 μm. Unlike the case of FIG. 7, the particle size is small and almost uniform, and the coarse particles observed in FIG. 7 are not recognized at all.

  As shown in FIG. 8, when dispersing the titanyl phthalocyanine crystal produced in a state where the primary particles are small, the particle size after dispersion is made small (0.25 μm or less, more preferably 0.2 μm or less). For this purpose, it is possible to disperse by giving a share sufficient to loosen the secondary particles formed by aggregation of the primary particles. As a result, since the energy more than necessary is not given, a dispersion liquid with a fine particle size distribution can be easily produced without producing the result that a part of the particles are easily transferred to a crystal form other than the desired crystal form as described above. It is possible.

  The particle size referred to here is a volume average particle size and is determined by an ultracentrifugal automatic particle size distribution analyzer: CAPA-700 (manufactured by Horiba, Ltd.). At this time, the particle size (Median system) corresponding to 50% of the cumulative distribution was calculated. However, this method may not be able to detect a very small amount of coarse particles. Therefore, in order to obtain more details, it is important to observe the titanyl phthalocyanine crystal powder or dispersion directly with an electron microscope and determine its size. It is.

  As a result of further observation of the dispersion and examination of micro defects, the above phenomenon was understood as follows. Usually, in the method of measuring the average particle size, when an extremely large particle is present in several% or more, the presence can be detected, but it is about 1% or less of the whole. When the amount is too small, the measurement is below the detection limit. As a result, the presence of coarse particles is not detected only by measuring the average particle size, making it difficult to interpret the above minute defects.

  9 and 10 show photographs observing the state of two types of dispersions in which only the dispersion time is changed while fixing the dispersion conditions. A photograph of a dispersion liquid having a short dispersion time under the same conditions is shown in FIG. 9, and it is observed that coarse particles remain as compared with FIG. 10 having a long dispersion time. The black particles in FIG. 9 are coarse particles.

  The average particle size and particle size distribution of these two types of dispersions were measured according to a known method using a commercially available particle size distribution measuring device (manufactured by Horiba: ultracentrifugal automatic particle size distribution measuring device, CAPA700). The result is shown in FIG. “A” in FIG. 11 corresponds to the dispersion shown in FIG. 9, and “B” corresponds to the dispersion shown in FIG. When both are compared, there is almost no difference in the particle size distribution. In addition, the average particle diameter values of the two are “A” of 0.29 μm and “B” of 0.28 μm, and taking into account measurement errors, there is no difference between the two.

  Therefore, it is understood that the remaining of a very small amount of coarse particles cannot be detected only by the definition of the known average particle size (particle size), and it is not possible to cope with the recent high-resolution negative / positive development. The presence of such a minute amount of coarse particles can be recognized for the first time by observing the coating solution at the microscope level.

  In response to such a fact, it is an effective means to make the primary particles produced at the time of crystal conversion as small as possible. For this purpose, in order to complete the crystal conversion in a short time while selecting the appropriate crystal conversion solvent as described above and improving the crystal conversion efficiency, the solvent and titanyl phthalocyanine water paste (the raw material prepared as described above) are used. It can be seen that a technique using strong agitation is effective to sufficiently bring a contact of

  By adopting such a crystal conversion method, a titanyl phthalocyanine crystal having a small primary particle size (0.25 μm or less, more preferably 0.2 μm or less) can be obtained. In addition to the technique described in Patent Document 2, it is an important means in the present invention to use the above-described technique (crystal conversion method for obtaining fine titanyl phthalocyanine crystals) as necessary.

  Subsequently, the crystallized titanyl phthalocyanine crystal is immediately filtered to be separated from the crystal conversion solvent. This filtration is performed by using a filter of an appropriate size. In this case, it is most appropriate to use vacuum filtration.

  Thereafter, the separated titanyl phthalocyanine crystal is heat-dried as necessary. Any known dryer can be used for heating and drying, but a blower-type dryer is preferable when the drying is performed in the atmosphere. Furthermore, drying under reduced pressure is a very effective means in order to increase the drying speed and to exhibit the effects of the present invention more remarkably. In particular, this is an effective means for a material that decomposes at a high temperature or changes its crystal form. In particular, it is effective to dry in a state where the degree of vacuum is higher than 10 mmHg.

  The thus obtained titanyl phthalocyanine crystal having a specific crystal type is extremely useful as a charge generating material for an electrophotographic photoreceptor. However, as described above, the crystal form is unstable, and the crystal form is easily transferred when a dispersion is prepared. However, by synthesizing primary particles into infinitely small particles as in the present invention, a dispersion with a small average particle diameter can be prepared without giving an excessive share during the preparation of the dispersion, and the crystal type is also extremely high. It can be produced stably (without changing the synthesized crystal form).

  Next, a method for preparing the dispersion will be described.

  A general method is used for the preparation of the dispersion, and the titanyl phthalocyanine crystal is dispersed in a suitable solvent together with a binder resin as necessary by using a ball mill, an attritor, a sand mill, a bead mill, an ultrasonic wave, or the like. It is obtained. At this time, the binder resin may be selected depending on the electrostatic characteristics of the photoreceptor, and the solvent may be selected depending on the wettability to the pigment, the dispersibility of the pigment, and the like.

  As already mentioned, the titanyl phthalocyanine crystal having a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to CuKα rays (wavelength 1.542 mm) is It is known that a crystal transition easily occurs to another crystal type due to a stress such as a dynamic share. This tendency does not change in the titanyl phthalocyanine crystal used in the present invention. In other words, in order to produce a dispersion containing fine particles, it is necessary to devise a dispersion method, but the stability of the crystal form and the micronization tend to be in a trade-off relationship. Although there are methods for avoiding this by optimizing the dispersion conditions, all of them make the manufacturing conditions extremely narrow, and a simpler method is desired. In order to solve this problem, the following method is also an effective means.

  That is, it is a method in which a dispersion liquid in which the particles are made as fine as possible is produced within a range where crystal transition does not occur, and then filtered through an appropriate filter. This method is a very effective means in that it can remove a minute amount of coarse particles that cannot be visually observed (or cannot be detected by particle size measurement), and that the particle size distribution is uniform. Specifically, the dispersion prepared as described above is filtered through a filter having an effective pore size of 3 μm or less, more preferably 1 μm or less, thereby completing the dispersion. Also by this method, a dispersion containing only titanyl phthalocyanine crystals having a small particle size (0.25 μm or less, more preferably 0.2 μm or less) can be produced, and a photoconductor using the dispersion is mounted on an image forming apparatus. By using it, the effect of the present application is made more remarkable.

  The filter for filtering the dispersion varies depending on the size of coarse particles to be removed, but according to the study by the present inventors, as a photoreceptor used in an electrophotographic apparatus that requires a resolution of about 600 dpi. The presence of coarse particles at least larger than 3 μm affects the image. Therefore, a filter with an effective pore size of 3 μm or less should be used. More preferably, a filter having an effective pore size of 1 μm or less is used. By performing such a filtering process, coarse particles finer than the effective pore size can be removed, and a dispersion having a narrow particle size distribution and no coarse particles can be produced.

  As for the effective pore size, the finer the particle, the more effective the removal of coarse particles. However, if the particle size is too fine, the necessary pigment particles themselves are also filtered, and therefore there is an appropriate size. In addition, if it is too fine, it takes time for filtration, clogging of the filter, and excessive load is applied when liquid is sent using a pump or the like. As a matter of course, a material having resistance to the solvent used in the dispersion to be filtered is used as the material of the filter used here.

  During filtration, if the amount of coarse particles in the dispersion to be filtered is too large, the amount of pigment to be removed increases, and the solid content concentration of the dispersion after filtration changes, which is not preferable. Therefore, an appropriate particle size distribution (particle size, standard deviation) exists when performing filtration. As in the present invention, there is no pigment loss due to filtration, filter clogging, etc., and in order to perform filtration efficiently, the volume average particle size of the dispersion before filtration is 0.25 μm or less, and its standard deviation is It is desirable to disperse to 0.2 μm or less.

  By adding such an operation of filtering the dispersion, coarse particles can be removed, and as a result, background contamination generated on the photoconductor using the dispersion can be reduced. As described above, the finer the filter, the greater the effect (reliable), but there are cases where the pigment particles themselves are filtered. In such a case, using the titanyl phthalocyanine primary particles described above in combination with the technique for refining and synthesizing the particles produces a very large effect.

  That is, (i) by synthesizing and using refined titanyl phthalocyanine, the dispersion time can be shortened and the dispersion stress can be reduced, and the possibility of crystal transition in dispersion is reduced. (Ii) Since the size of coarse particles remaining by dispersion is smaller than that in the case where the particles are not refined, a smaller filter can be used, and the effect of removing coarse particles becomes more reliable. In addition, the amount of titanyl phthalocyanine particles to be removed is reduced, and there is little change in the composition of the dispersion before and after filtration, which enables stable production. (Iii) As a result, the manufactured photoreceptor is stably produced with a high resistance to soiling.

  Next, the electrophotographic photosensitive member used in the present invention will be described in detail with reference to the drawings.

  FIG. 12 is a cross-sectional view showing a structural example of the electrophotographic photosensitive member used in the present invention. On the conductive support (31), a titanyl phthalocyanine crystal having a specific crystal type with the specific particle size (charge generating material). ) As a main component and a charge transport layer (37) whose main component is a charge transport material are stacked.

  FIG. 13 is a cross-sectional view showing another structural example of the electrophotographic photosensitive member used in the present invention, and a titanyl phthalocyanine crystal having the specific particle size and the specific particle size on the conductive support (31). A charge generation layer (35) mainly composed of (charge generation material) and a charge transport layer (37) mainly composed of a charge transport material are laminated, and a protective layer (39) is further formed on the charge transport layer. It has a configuration that is provided.

As the conductive support (31), a material having a volume resistance of 10 ¹⁰ Ω · cm or less, for example, a metal such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, oxidation A method of extruding and drawing metal oxides such as indium by film deposition or sputtering, or coating a film or cylindrical plastic or paper, or a plate of aluminum, aluminum alloy, nickel, stainless steel, etc. After forming the tube, it is possible to use a tube that has been surface-treated by cutting, superfinishing, polishing, or the like. Moreover, the endless nickel belt and the endless stainless steel belt disclosed in Patent Document 6 can also be used as the conductive support (31). Of these, a cylindrical support made of aluminum, which can be easily subjected to the anodic oxide film treatment, can be most preferably used. As used herein, aluminum includes both pure aluminum and aluminum alloys. Specifically, aluminum of the JIS 1000s, 3000s, and 6000s is most suitable. Anodized films are obtained by anodizing various metals and various alloys in an electrolyte solution. Among them, a film called anodized aluminum or an aluminum alloy that has been anodized in an electrolyte solution is used in the present invention. Is the most suitable. In particular, it is excellent in preventing point defects (black spots, background stains) that occur when used in reversal development (negative / positive development).

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 , electrolysis voltage: 5 to 30 V, treatment time: 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 insulation, the surface is very unstable. For this reason, there is a change with time after fabrication, and the physical property value of the anodized film is likely to change. In order to avoid this, it is desirable 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), it will not only adversely affect the quality of the coating film formed on it, but also generally a low resistance component will remain. It can also be a cause. The cleaning may be performed once with pure water, but is usually performed at another stage. At this time, it is preferable that the final cleaning liquid is as clean as possible (deionized). Moreover, it is desirable to perform physical rubbing cleaning with a contact member in one of the other cleaning processes. The film thickness of the anodized film formed as described above is desirably about 5 to 15 μm. If it is too thin, the barrier effect as an anodic oxide film is not sufficient, and if it is too thick, the time constant as an electrode becomes too large, resulting in the generation of residual potential and the response of the photoreceptor. There is a case.

  In addition to the above, a conductive powder dispersed in a suitable binder resin and coated on the support can be used as the conductive support (31) of the present invention. Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, and silver, or metal oxide powder such as conductive tin oxide and ITO. It is done. The binder resin used at the same time is polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. , Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, Examples thereof include thermoplastic, thermosetting resins, and photocurable resins such as melamine resin, urethane resin, phenol resin, and alkyd resin. Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.

  Furthermore, a heat-shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, polytetrafluoroethylene fluororesin on a suitable cylindrical substrate. Those provided with a conductive layer can be used favorably as the conductive support (31) of the present invention.

  Next, the photosensitive layer will be described. As described above, as the photosensitive layer, a laminated type composed of the charge generation layer (35) and the charge transport layer (37) exhibits excellent characteristics in sensitivity and durability, and is used favorably.

  The charge generation layer (35) has, as a charge generation material, a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to CuKα characteristic X-rays (wavelength 1.542 mm). Further, it has major peaks at 9.4 °, 9.6 °, and 24.0 °, and has a peak at 7.3 ° as a diffraction peak at the lowest angle side. There is no peak between the peak at 3 ° and the peak at 9.4 °, and there is no peak at 26.3 °. The average particle size of the primary particles is 0 during crystal synthesis or by dispersion filtration. A layer mainly composed of titanyl phthalocyanine crystal of 25 μm or less (preferably 0.2 μm or less).

  In the charge generation layer (35), the pigment is dispersed in a suitable solvent together with a binder resin as necessary using a ball mill, an attritor, a sand mill, an ultrasonic wave, etc., and this is coated on a conductive support. It is formed by drying.

  As the binder resin used for the charge generation layer (35) as necessary, the binder resin used for the charge generation layer (35) as needed may be polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicon. Resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly-N-vinylcarbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, Polyphenylene oxide, polyamide, polyvinyl pyridine, cellulosic resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone and the like can be mentioned. The amount of the binder resin is suitably 0 to 500 parts by weight, preferably 10 to 300 parts by weight with respect to 100 parts by weight of the charge generating material.

  Examples of the solvent used here include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin and the like. As a coating method for the coating solution, a dip coating method, spray coating, beat coating, nozzle coating, spinner coating, ring coating, or the like can be used. The film thickness of the charge generation layer 35 is suitably about 0.01 to 5 μm, preferably 0.1 to 2 μm.

  The charge transport layer (37) can be formed by dissolving or dispersing the charge transport material and the binder resin in a suitable solvent, and applying and drying the solution on the charge generation layer. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.

  Charge transport materials include hole transport materials and electron transport materials.

  Examples of the electron transporting material include chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide and benzoquinone derivatives.

  Examples of hole transport materials include poly-N-vinylcarbazole 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, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazolines Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc., bisstilbene derivatives, enamine derivatives, etc. Other known materials may be mentioned. These charge transport materials may be used alone or in combination of two or more.

  Binder resins include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, poly Vinylidene chloride, polyarate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin And thermoplastic or thermosetting resins such as alkyd resins.

  The amount of the charge transport material is 20 to 300 parts by weight, preferably 40 to 150 parts by weight, with respect to 100 parts by weight of the binder resin. The thickness of the charge transport layer is preferably about 5 to 100 μm.

  As the solvent used here, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used. Among them, the use of a non-halogen solvent is desirable for the purpose of reducing the environmental load. Specifically, cyclic ethers such as tetrahydrofuran, dioxolane and dioxane, aromatic hydrocarbons such as toluene and xylene, and derivatives thereof are preferably used.

  In addition, a polymer charge transport material having a function as a charge transport material and a function of a binder resin is also preferably used for the charge transport layer. The charge transport layer composed of these polymer charge transport materials is excellent in wear resistance. As the polymer charge transport material, known materials can be used, and in particular, a polycarbonate containing a triarylamine structure in the main chain and / or side chain is preferably used. Among these, polymer charge transport materials represented by the formulas (I) to (X) are preferably used, and these are exemplified below and specific examples are shown.

  (I) Formula

In the formula, 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, and R ₅ and R ₆ are substituted or unsubstituted. Substituted aryl group, o, p, q are each independently an integer of 0 to 4, k, j are compositions, 0.1 ≦ k ≦ 1, 0 ≦ j ≦ 0.9, n is the number of repeating units Represents an integer of 5 to 5000. X represents an aliphatic divalent group, a cycloaliphatic divalent group, or a divalent group represented by the following general formula. In the formula (I), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

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-, -SO2-, -CO-, -CO-O-Z-O-CO- (wherein Z represents an aliphatic divalent group) or

(A represents an integer of 1 to 20, b represents an integer of 1 to 2000, and 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. )

(II) In the formula, 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.
(III) Formula

In the formula, R ₉ and R ₁₀ represent 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 case of 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.

(IV) Formula In the formula, R ₁₁ and R ₁₂ represent a substituted or unsubstituted aryl group, Ar ₇ , Ar ₈ and Ar ₉ represent 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.

(V) In the formula, 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 are substituted or unsubstituted ethylene groups, Or a substituted or unsubstituted vinylene group. X, k, j and n are the same as in the case of 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.

(VI) In the formula, R ₁₅ , R ₁₆ , R ₁₇ and R ₁₈ are substituted or unsubstituted aryl groups, Ar ₁₃ , Ar ₁₄ , Ar ₁₅ and Ar ₁₆ are the same or different arylene groups, Y ₁ and Y _2. , Y ₃ represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group. Also good. X, k, j and n are the same as in the case of the equation (V). In the formula (I), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

(VII) Formula In the formula, 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 case of 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.

(VIII) Formula In the formula, R ₂₁ represents a substituted or unsubstituted aryl group, and Ar ₂₀ , Ar ₂₁ , Ar ₂₂ , and Ar ₂₃ 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 (VIII), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

(IX) Formula In the formula, 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 case of 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.

(X) wherein _{formulas, R 26,} R ₂₇ is a substituted or unsubstituted aryl _{group, Ar 29, Ar 30, Ar} 31 represents an identical or different arylene groups. X, k, j and n are the same as in the case of 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.

  Further, as the polymer charge transport material used in the charge transport layer, in addition to the polymer charge transport material described above, in the state of the monomer or oligomer having an electron donating group at the time of film formation of the charge transport layer, A polymer having a two-dimensional or three-dimensional crosslinked structure is finally included by carrying out a curing reaction or a crosslinking reaction.

  A charge transport layer composed of a polymer having these electron donating groups, or a polymer having a crosslinked structure is excellent in wear resistance. Usually, in the electrophotographic process, since the charging potential (unexposed portion potential) is constant, if the surface layer of the photoreceptor is worn by repeated use, the electric field strength applied to the photoreceptor increases accordingly. As the electric field strength increases, the occurrence frequency of scumming increases. Therefore, the high wear resistance of the photosensitive member is advantageous for scumming. The charge transport layer composed of a polymer having these electron donating groups is a polymer compound, so it has excellent film-forming properties and has a charge transport site compared to a charge transport layer composed of a low molecular weight dispersed polymer. It can be configured with high density and has excellent charge transport capability. For this reason, a photoreceptor having a charge transport layer using a polymer charge transport material can be expected to have a high response speed.

  Examples of other polymers having an electron donating group include known monomer copolymers, block polymers, graft polymers, star polymers, and, for example, Patent Document 6, Patent Document 7, Patent Document 8, and the like. It is also possible to use a cross-linked polymer having an electron donating group as disclosed in the above.

  In the present invention, a plasticizer or a leveling agent may be added to the charge transport layer (37). As the plasticizer, those used as a plasticizer for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is suitably about 0 to 30% by weight based on the binder resin. As the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain are used, and the amount used is 0 to 0 with respect to the binder resin. 1% by weight is suitable.

  In the electrophotographic photoreceptor of the present invention, an intermediate layer can be provided between the conductive support (31) and the photosensitive layer. In general, the intermediate layer is mainly composed of a resin. However, considering that the photosensitive layer is coated with a solvent on these resins, it is desirable that the resin be a resin having high solvent resistance with respect to a general organic solvent. . Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. Further, fine powder pigments of metal oxides exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like may be added to the intermediate layer in order to prevent moire and reduce residual potential.

These intermediate layers can be formed by using an appropriate solvent and coating method like the above-mentioned photosensitive layer. Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the intermediate layer of the present invention. In addition, in the intermediate layer of the present invention, Al ₂ O ₃ is provided by anodic oxidation, organic substances such as polyparaxylylene (parylene), SiO ₂ , SnO ₂ , TiO ₂ , ITO, CeO _2, etc. Those provided with an inorganic material by a vacuum thin film forming method can also be used satisfactorily. In addition, known ones can be used. The thickness of the intermediate layer is suitably from 0 to 5 μm.

  In the electrophotographic photoreceptor of the present invention, a protective layer may be provided on the photosensitive layer for the purpose of protecting the photosensitive layer. In recent years, computers have been used on a daily basis, and there has been a demand for miniaturization of devices as well as high-speed output by printers. Therefore, by providing a protective layer and improving the durability, it is possible to use the photosensitive member of the present invention with high sensitivity and no abnormal defects.

  In the photoreceptor of the present invention, a protective layer (39) may be provided on the photosensitive layer for the purpose of protecting the photosensitive layer. Materials used for the protective layer (39) include ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, aryl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone. , Polybutylene, polybutylene terephthalate, polycarbonate, polyarylate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane , Resins such as polyvinyl chloride, polyvinylidene chloride, and epoxy resin. Of these, polycarbonate or polyarylate can be most preferably used.

  In addition to the protective layer, fluororesins such as polytetrafluoroethylene, silicone resins, and inorganic fillers such as titanium oxide, tin oxide, potassium titanate, and silica for the purpose of improving abrasion resistance (inorganic pigments) ), Or an organic filler (organic pigment) dispersed therein can be added.

  Among the filler materials used for the protective layer of the photoreceptor, examples of the organic filler material include fluororesin powder such as polytetrafluoroethylene, silicone resin powder, a-carbon powder, and the like. Metals such as copper, tin, aluminum and indium, silica, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, tin oxide doped with antimony, tin doped indium oxide and other metals Inorganic materials such as oxide and potassium titanate can be mentioned. In particular, it is advantageous to use an inorganic material among them from the viewpoint of the hardness of the filler. In particular, silica, titanium oxide, and alumina can be used effectively.

  The filler concentration in the protective layer varies depending on the type of filler used and also on the electrophotographic process conditions using the photoconductor, but the ratio of filler to the total solid content on the outermost layer side of the protective layer is preferably 5% by weight or more, preferably It is 10% by weight or more and 50% by weight or less, preferably about 30% by weight or less.

  The volume average particle size of the filler used is preferably in the range of 0.1 μm to 2 μm, and preferably in the range of 0.3 μm to 1 μm. In this case, if the average particle size is too small, the wear resistance is not sufficiently exhibited, and if it is too large, the surface property of the coating film is deteriorated or the coating film itself cannot be formed.

  In addition, unless otherwise indicated, the average particle diameter of the filler in this invention is a volume average particle diameter, and is calculated | required with the ultracentrifugal automatic particle size distribution measuring apparatus: CAPA-700 (made by Horiba Seisakusho). At this time, the particle size (Median system) corresponding to 50% of the cumulative distribution was calculated. In addition, it is important that the standard deviation of each particle measured simultaneously is 1 μm or less. If the standard deviation is larger than this, the particle size distribution may be too wide, and the effects of the present invention may not be obtained remarkably.

  Further, the pH of the filler used in the present invention greatly affects the resolution and the dispersibility of the filler. One possible reason is that hydrochloric acid or the like remains in the filler, particularly the metal oxide, during production. When the remaining amount is large, the occurrence of image blur is unavoidable, and depending on the remaining amount, the dispersibility of the filler may be affected.

  Another reason is due to the difference in chargeability on the surface of the filler, particularly the metal oxide. Usually, particles dispersed in a liquid are charged positively or negatively, and ions having opposite charges gather to try to keep it electrically neutral, and an electric double layer is formed there. The dispersed state of the particles is stabilized. The potential (zeta potential) gradually decreases with increasing distance from the particle, and the potential in a region that is sufficiently away from the particle and electrically neutral is zero. Therefore, the stability increases as the repulsive force of the particles increases due to an increase in the absolute value of the zeta potential, and the particles tend to aggregate and become unstable as they approach zero. On the other hand, the zeta potential varies greatly depending on the pH value of the system, and at a certain pH value, the potential becomes zero and has an isoelectric point. Therefore, the dispersion system is stabilized by increasing the absolute value of the zeta potential as far as possible from the isoelectric point of the system.

  In the configuration of the present invention, the filler having a pH at the isoelectric point of at least 5 is preferably from the viewpoint of image blur suppression, and the more basic the filler, the higher the effect. It was confirmed that there was. The filler having a high basic pH at the isoelectric point has a higher zeta potential when the system is acidic, thereby improving dispersibility and stability.

  Here, the pH of the filler in the present invention is the pH value at the isoelectric point from the zeta potential. At this time, the zeta potential was measured with a laser zeta potentiometer manufactured by Otsuka Electronics Co., Ltd.

Furthermore, as the filler that is less likely to cause image blurring, a filler having high electrical insulation (specific resistance is 10 ¹⁰ Ω · cm or more) is preferable, and the filler having a pH of 5 or more or the filler having a dielectric constant of 5 or more. The ones shown can be used particularly effectively. In addition, a filler having a pH of 5 or more or a filler having a dielectric constant of 5 or more can be used alone, or two or more fillers having a pH of 5 or less and a filler having a pH of 5 or more can be mixed. It is also possible to use a mixture of two or more fillers having a dielectric constant of 5 or less and a filler having a dielectric constant of 5 or more. Among these fillers, α-type alumina, which has high insulation properties, high thermal stability, and high wear resistance, is a hexagonal close-packed structure, from the viewpoint of suppressing image blur and improving wear resistance. It is particularly useful.

The specific resistance of the filler used in the present invention is defined as follows. Since the specific resistance value of a powder such as a filler varies depending on the filling rate, it is necessary to measure under certain conditions. In the present invention, the specific resistance value of the filler was measured using an apparatus having the same configuration as the measurement apparatus shown in Patent Document 9 (FIG. 1) and Patent Document 10 (FIG. 1), and this value was used. . In the measuring device, the electrode area is 4.0 cm ² . Prior to the measurement, a load of 4 kg is applied to the electrode on one side for 1 minute, and the sample amount is adjusted so that the distance between the electrodes is 4 mm. At the time of measurement, the measurement is performed with the upper electrode weight (1 kg) loaded, and the applied voltage is measured at 100V. The area of 10 ⁶ Ω · cm or higher was measured with a HIGH REISTANCE METER (Yokogawa Hewlett Packard), and the area below it was measured with a digital multimeter (Fluk). The specific resistance value thus obtained is defined as the specific resistance value in the present invention.

  The dielectric constant of the filler was measured as follows. Using a cell similar to the measurement of the specific resistance as described above, after applying a load, the capacitance was measured, and the dielectric constant was determined from this. For the measurement of the capacitance, a dielectric loss measuring device (Ando Electric) was used.

Further, these fillers can be surface-treated with at least one kind of surface treatment agent, and it is preferable from the viewpoint of dispersibility of the fillers. Decreasing the dispersibility of the filler not only increases the residual potential, but also decreases the transparency of the coating, causes defects in the coating, and decreases the wear resistance. It can develop into a big problem. As the surface treatment agent, all conventionally used surface treatment agents can be used, but a surface treatment agent capable of maintaining the insulating properties of the filler is preferable. For example, a titanate coupling agent, an aluminum coupling agent, a zircoaluminate coupling agent, a higher fatty acid, etc., or a mixing treatment of these with a silane coupling agent, Al ₂ O ₃ , TiO ₂ , ZrO ₂ , Silicone, aluminum stearate, or the like, or a mixture thereof is more preferable in terms of filler dispersibility and image blur. The treatment with the silane coupling agent is strongly influenced by image blur, but the influence may be suppressed by performing a mixing treatment of the surface treatment agent and the silane coupling agent. The surface treatment amount varies depending on the average primary particle size of the filler used, but is preferably 3 to 30 wt%, more preferably 5 to 20 wt%. If the surface treatment amount is less than this, the filler dispersion effect cannot be obtained, and if it is too much, the residual potential is significantly increased. These filler materials may be used alone or in combination of two or more. The surface treatment amount of the filler is defined by the weight ratio of the surface treatment agent to be used with respect to the filler amount as described above.

  These filler materials can be dispersed by using an appropriate disperser. Further, from the viewpoint of the transmittance of the protective layer, it is preferable that the filler used is dispersed to the primary particle level and has less aggregates.

  Further, the protective layer (39) may contain a charge transport material for reducing residual potential and improving responsiveness. As the charge transport material, the materials described in the description of the charge transport layer can be used. When a low molecular charge transport material is used as the charge transport material, a concentration gradient in the protective layer may be provided. In order to improve wear resistance, it is an effective means to reduce the concentration of the surface side. The concentration here refers to the ratio of the weight of the low molecular charge transporting material to the total weight of all the materials constituting the protective layer, and the concentration gradient is a gradient that lowers the concentration on the surface side in the above weight ratio. It shows that. The use of a polymer charge transport material is very advantageous in terms of enhancing the durability of the photoreceptor.

  As a method for forming the protective layer, a normal coating method is employed. The thickness of the protective layer is suitably about 0.1 to 10 μm. In addition to the above, a known material such as a-C or a-SiC formed by a vacuum thin film forming method can be used as the protective layer.

  In addition, as the binder resin for the protective layer, the polymer charge transport material described in the section of the charge transport layer can be used. As the effect when this is used, the effect of improving the wear resistance and the high-speed charge transport can be obtained as described in the section of the charge transport layer. Moreover, the protective layer which consists of a crosslinked structure is also used effectively as a binder structure of a protective layer. Regarding the formation of a cross-linked structure, a reactive monomer having a plurality of cross-linkable functional groups in one molecule is used to cause a cross-linking reaction using light or thermal energy to form a three-dimensional network structure. is there. This network structure functions as a binder resin and exhibits high wear resistance.

  Moreover, it is a very effective means to use a monomer having a charge transporting ability in whole or in part as the reactive monomer. By using such a monomer, a charge transporting site is formed in the network structure, and the function as a protective layer can be sufficiently expressed. A reactive monomer having a triarylamine structure is effectively used as the monomer having charge transporting ability.

  The charge transport layer having such a network structure has high wear resistance, but has a large volume shrinkage during the crosslinking reaction, and if it is too thick, cracks may occur. In such a case, the protective layer may be a laminated structure, a low molecular dispersion polymer protective layer may be used for the lower layer (photosensitive layer side), and a protective layer having a crosslinked structure may be formed on the upper layer (surface side). good.

  As described above, the use of a polymer charge transport material for the photosensitive layer (charge transport layer) or the provision of a protective layer on the surface of the photoreceptor increases the durability (wear resistance) of each photoreceptor. In addition, when used in a tandem type full-color image forming apparatus as described later, a new effect not found in the monochrome image forming apparatus is also produced.

  In the case of a full-color image, various types of images are input, but on the contrary, a typical image may also be input. For example, the presence of a seal in a Japanese document or the like. Something like indicia is usually located towards the edge of the image area, and the colors used are also limited. In a state in which a random image is always written, image writing, development, and transfer are performed on the photoconductor in the image forming element on average. When many image formations are repeated or only a specific image forming element is used, the durability balance is lost. When a photoconductor having a low surface durability (physical / chemical / mechanical) is used in such a state, this difference becomes prominent and easily causes an image problem. On the other hand, when the photoconductor is made highly durable, the amount of such local change is small, and as a result, it becomes difficult to appear as a defect on the image, so that high durability is achieved and the stability of the output image is improved. This is very effective.

  Hereinafter, the present invention will be described by way of examples, but the present invention is not limited by the examples. All parts are parts by weight.

First, a synthesis example of a charge generation material (titanyl phthalocyanine crystal) will be described.
(Comparative Synthesis Example 1)
A pigment was prepared according to the cited document 2. That is, 29.2 g of 1,3-diiminoisoindoline and 200 ml of sulfolane are mixed, and 20.4 g of titanium tetrabutoxide is added dropwise under a nitrogen stream. After completion of the dropwise addition, the temperature was gradually raised to 180 ° C., and the reaction was carried out by stirring for 5 hours while maintaining the reaction temperature between 170 ° C. and 180 ° C. After completion of the reaction, the mixture was allowed to cool, and then the precipitate was filtered, washed with chloroform until the powder turned blue, then washed several times with methanol, further washed several times with hot water at 80 ° C., and dried. Crude titanyl phthalocyanine was obtained. Crude titanyl phthalocyanine is dissolved in 20 times the amount of concentrated sulfuric acid, added dropwise to 100 times the amount of ice water with stirring, the precipitated crystals are filtered, and then ion-exchanged water (pH: 7.0, until the washing solution becomes neutral). Repeated washing with specific conductivity (1.0 μS / cm) (pH value of ion-exchanged water after washing was 6.8, specific conductivity was 2.6 μS / cm), wet cake of titanyl phthalocyanine pigment ( Water paste) was obtained. 40 g of this obtained wet cake (water paste) was put into 200 g of tetrahydrofuran, stirred for 4 hours, filtered and dried to obtain titanyl phthalocyanine powder (referred to as pigment 1).

  The solid content concentration of the wet cake was 15 wt%. The weight ratio of the crystal conversion solvent to the wet cake is 33 times. Incidentally, the raw material of Comparative Synthesis Example 1 does not use a halide.

  When the obtained titanyl phthalocyanine powder was subjected to X-ray diffraction spectrum measurement under the following conditions, the Bragg angle 2θ with respect to the Cu—Kα ray (wavelength 1.542 mm) was 27.2 ± 0.2 °, and the maximum peak and the minimum angle 7 A titanyl phthalocyanine powder having a peak at .3 ± 0.2 °, no peak between the peak at 7.3 ° and the peak at 9.4 °, and no peak at 26.3 ° Was obtained. The result is shown in FIG.

  A part of the water paste obtained in Comparative Synthesis Example 1 was dried at 80 ° C. under reduced pressure (5 mmHg) for 2 days to obtain a low crystalline titanyl phthalocyanine powder. The X-ray diffraction spectrum of the dry powder of water paste is shown in FIG.

(X-ray diffraction spectrum measurement conditions)
X-ray tube: Cu
Voltage: 50kV
Current: 30mA
Scanning speed: 2 ° / min Scanning range: 3 ° to 40 °
Time constant: 2 seconds (Comparative synthesis example 2)
A pigment was produced according to the method described in Patent Document 11 and Example 1. That is, the wet cake produced in the previous Comparative Synthesis Example 1 was dried, 1 g of the dried product was added to 50 g of polyethylene glycol, and sand milling was performed with 100 g of glass beads. After the crystal transition, the resultant was washed successively with dilute sulfuric acid and an aqueous ammonium hydroxide solution and dried to obtain a pigment (referred to as pigment 2). The raw material of Comparative Synthesis Example 2 does not use a halide.

(Comparative Synthesis Example 3)
A pigment was prepared according to the method described in Patent Document 12 and Production Example 1. That is, the wet cake prepared in Comparative Synthesis Example 1 was dried, and 1 g of the dried product was stirred (50 ° C.) in a mixed solvent of 10 g of ion exchanged water and 1 g of monochlorobenzene for 1 hour, and then methanol and ion exchanged water. The pigment was obtained by washing and drying (referred to as pigment 3). The raw material of Comparative Synthesis Example 3 does not use a halide.

(Comparative Synthesis Example 4)
A pigment was produced according to the method described in the production example of Patent Document 13. That is, 9.8 g of phthalodinitrile and 75 ml of 1-chloronaphthalene are stirred and mixed, and 2.2 ml of titanium tetrachloride is added dropwise under a nitrogen stream. After completion of the dropwise addition, the temperature was gradually raised to 200 ° C., and the reaction was carried out by stirring for 3 hours while maintaining the reaction temperature between 200 ° C. and 220 ° C. After completion of the reaction, the mixture was allowed to cool to 130 ° C. and filtered while hot, then washed with 1-chloronaphthalene until the powder turned blue, then washed several times with methanol, and further with hot water at 80 ° C. After washing twice, it was dried to obtain a pigment (referred to as pigment 4). As a raw material of Comparative Synthesis Example 4, a halide is used.

(Comparative Synthesis Example 5)
A pigment was produced according to the method described in Patent Document 14 and Synthesis Example 1. That is, 5 parts of α-type TiOPc was subjected to crystal conversion treatment at 100 ° C. for 10 hours with a sand grinder together with 10 g of sodium chloride and 5 g of acetophenone. This was washed with ion-exchanged water and methanol, purified with dilute sulfuric acid aqueous solution, washed with ion-exchanged water until the acid content disappeared, and then dried to obtain a pigment (referred to as pigment 5). As a raw material of Comparative Synthesis Example 5, a halide is used.

(Comparative Synthesis Example 6)
A pigment was produced according to the method described in Patent Document 15 and Example 1. That is, 20.4 parts of O-phthalodinitrile and 7.6 parts of titanium tetrachloride were heated and reacted in 50 parts of quinoline at 200 ° C. for 2 hours, the solvent was removed by steam distillation, 2% hydrochloric acid, and then 2% The product was purified with an aqueous sodium hydroxide solution, washed with methanol and N, N-dimethylformamide, and then dried to obtain titanyl phthalocyanine. 2 parts of this titanyl phthalocyanine is dissolved little by little in 40 parts of 98% sulfuric acid at 5 ° C., and the mixture is stirred for about 1 hour while maintaining the temperature at 5 ° C. or less. Subsequently, the sulfuric acid solution is slowly poured into 400 parts of ice water stirred at a high speed, and the precipitated crystals are filtered. The crystals are washed with distilled water until no acid remains, and a wet cake is obtained. The cake was stirred in 100 parts of THF for about 5 hours, filtered, washed with THF and dried to obtain a pigment (referred to as pigment 6). As a raw material of Comparative Synthesis Example 6, a halide is used.

(Comparative Synthesis Example 7)
A pigment was produced according to the method described in Patent Document 16 and Synthesis Example 2. That is, 10 parts of the wet cake prepared in the previous Comparative Synthesis Example 1 was mixed with 15 parts of sodium chloride and 7 parts of diethylene glycol, and milled for 60 hours with an automatic mortar under heating at 80 ° C. Next, sufficient washing was performed to completely remove sodium chloride and diethylene glycol contained in the treated product. After drying this under reduced pressure, 200 parts of cyclohexanone and glass beads having a diameter of 1 mm were added, and the mixture was treated with a sand mill for 30 minutes to obtain a pigment (referred to as pigment 7). The raw material of Comparative Synthesis Example 7 does not use a halide.

(Comparative Synthesis Example 8)
A pigment was prepared according to the method for producing a titanyl phthalocyanine crystal of Patent Document 4. That is, 58 g of 1,3-diiminoisoindoline and 51 g of tetrabutoxytitanium were reacted in 210 mL of α-chloronaphthalene at 210 ° C. for 5 hours, and then washed with α-chloronaphthalene and dimethylformamide (DMF) in this order. Thereafter, it was washed with hot DMF, hot water and methanol and dried to obtain 50 g of titanyl phthalocyanine. 4 g of titanyl phthalocyanine was added to 400 g of concentrated sulfuric acid cooled to 0 ° C., followed by stirring at 0 ° C. for 1 hour. After confirming that phthalocyanine was completely dissolved, it was added to a 800 mL water / 800 mL toluene mixture cooled to 0 ° C. After stirring at room temperature for 2 hours, the precipitated phthalocyanine mixed crystal was separated from the mixed solution and washed with methanol and water in this order. After confirming the neutrality of the washing water, the phthalocyanine mixed crystal was filtered from the washing water and dried to obtain 2.9 g of titanyl phthalocyanine mixed crystal. The raw material of Comparative Synthesis Example 8 does not use a halide.

(Synthesis Example 1)
In accordance with the method of Comparative Synthesis Example 1, a titanyl phthalocyanine pigment water paste was synthesized, and crystal conversion was performed as follows to obtain phthalocyanine crystals having smaller primary particles than Comparative Synthesis Example 1.

  400 parts of tetrahydrofuran was added to 60 parts of the water paste before crystal conversion obtained in Comparative Synthesis Example 1, and the mixture was stirred vigorously (2000 rpm) with a homomixer (Kennis, MARKIIf model) at room temperature. When the color changed to light blue (20 minutes after the start of stirring), stirring was stopped and filtration under reduced pressure was immediately performed. The crystals obtained on the filtration device were washed with tetrahydrofuran to obtain a wet cake of pigment. This was dried under reduced pressure (5 mmHg) at 70 ° C. for 2 days to obtain 8.5 parts of titanyl phthalocyanine crystals (referred to as pigment 9). The raw material of Synthesis Example 1 does not use a halide. The solid content concentration of the wet cake was 15 wt%. The weight ratio of the crystal conversion solvent to the wet cake is 44 times.

  A portion of titanyl phthalocyanine (water paste) before crystal transformation prepared in Comparative Synthesis Example 1 was diluted with ion-exchanged water to approximately 1% by weight, and the surface was scooped with a copper net having been subjected to conductive treatment. The particle size of phthalocyanine was observed with a transmission electron microscope (TEM, Hitachi: H-9000NAR) at a magnification of 75000 times. The average particle size was determined as follows.

  The TEM image observed as described above is taken as a TEM photograph, and 30 titanyl phthalocyanine particles (a shape close to a needle shape) projected are arbitrarily selected, and the size of each major axis is measured. The arithmetic average of the major diameters of the 30 individuals measured was determined as the average particle size.

  The average particle size in the water paste in Synthesis Example 1 determined by the above method was 0.06 μm.

  In addition, the titanyl phthalocyanine crystal after crystal conversion just before filtration in Comparative Synthesis Example 1 and Synthesis Example 1 was diluted with tetrahydrofuran to about 1% by weight, and observed in the same manner as the above method. The average particle size obtained as described above is shown in Table 1. In addition, the titanyl phthalocyanine crystal produced in Comparative Synthesis Example 1 and Synthesis Example 1 did not necessarily have the same shape of all crystals (a shape close to a triangle, a shape close to a square, etc.). For this reason, the calculation was performed with the length of the largest diagonal line of the crystal as the major axis.

The pigments 2 to 8 produced in Comparative Synthesis Examples 2 to 8 were measured for X-ray diffraction spectra by the same method as described above, and confirmed to be the same as the spectra described in the respective publications. Further, the X-ray diffraction spectrum of the pigment 9 produced in Synthesis Example 1 was identical to the spectrum of the pigment 1 produced in Comparative Synthesis Example 1. Table 2 shows the characteristics of each X-ray diffraction spectrum and the peak position of the X-ray diffraction spectrum of the pigment obtained in Comparative Synthesis Example 1.

(Dispersion Preparation Example 1)
Pigment 1 prepared in Comparative Synthesis Example 1 was dispersed under the following composition under the following conditions to prepare a dispersion as a charge generation layer coating solution.

Titanyl phthalocyanine pigment (Pigment 1) 15 parts Polyvinyl butyral (manufactured by Sekisui Chemical: BX-1) 10 parts 2-butanone 280 parts A commercially available bead mill disperser was used to dissolve polyvinyl butyral using PSZ balls having a diameter of 0.5 mm. All butanone and pigment were added, and the rotor rotation speed was 1200 r. p. m. And dispersion was performed for 30 minutes to prepare a dispersion (referred to as dispersion 1).

  In place of Pigment 1 used in Dispersion Preparation Example 1, pigments 2 to 9 prepared in Comparative Synthesis Examples 2 to 8 and Synthesis Example 1 were used, respectively. Dispersions were prepared as Preparation Examples 2 to 9 (referred to as Dispersions 2 to 9, respectively, corresponding to the pigment numbers).

(Dispersion Preparation Example 10)
The dispersion 1 prepared in Dispersion Preparation Example 1 was filtered using a cotton wind cartridge filter, TCW-1-CS (effective pore size 1 μm) manufactured by Advantech. During filtration, filtration was performed using a pump in a pressurized state (referred to as dispersion 10).

(Dispersion Preparation Example 11)
Dispersion was performed by pressure filtration in the same manner as in Dispersion Preparation Example 10, except that the filter used in Dispersion Preparation Example 10 was changed to an Advantech Co., Ltd. cotton wind cartridge filter, TCW-3-CS (effective pore size 3 μm). A liquid was prepared (referred to as Dispersion 11).

(Dispersion Preparation Example 12)
Except for changing the filter used in Dispersion Preparation Example 10 to Advantech Co., Ltd., Cotton Wind Cartridge Filter, TCW-5-CS (effective pore diameter 5 μm), pressure filtration was performed in the same manner as Dispersion Preparation Example 10, A dispersion was prepared (referred to as Dispersion 12).

(Dispersion Preparation Example 13)
Dispersion was performed by changing the dispersion conditions in Dispersion Preparation Example 1 as follows (referred to as Dispersion 13).

  Rotor rotation speed: 1000 r. p. m. For 20 minutes.

(Dispersion Preparation Example 14)
The dispersion prepared in Dispersion Preparation Example 13 was filtered using a cotton wind cartridge filter, TCW-1-CS (effective pore size 1 μm) manufactured by Advantech. During filtration, a pump was used and filtration was performed in a pressurized state. During the filtration, the filter was clogged, and it was not possible to filter all the dispersions. Therefore, the following evaluation has not been conducted.

  The particle size distribution of the pigment particles in the dispersion prepared as described above was measured by HORIBA, Ltd .: CAPA-700. The results are shown in Table 3.

(Photoreceptor Preparation Example 1)
An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following composition were sequentially applied and dried on an aluminum cylinder (JIS 1050) having a diameter of 100 mm. A charge generation layer and a 28 μm charge transport layer were formed to produce a laminated photoreceptor (referred to as photoreceptor 1). The film thickness of the charge generation layer was adjusted so that the transmittance of the charge generation layer at 780 nm was 20%. The charge generation layer transmittance was determined by applying a charge generation layer coating solution having the following composition to an aluminum cylinder wrapped with a polyethylene terephthalate film under the same conditions as the preparation of the photoreceptor, and the charge generation layer was applied as a comparison. The transmittance of 780 nm was evaluated with a commercially available spectrophotometer (Shimadzu: UV-3100).

Undercoat layer coating liquid Titanium oxide (CR-EL: manufactured by Ishihara Sangyo Co., Ltd.) 70 parts Alkyd resin 15 parts (Beckolite M6401-50-S (solid content 50%), manufactured by Dainippon Ink & Chemicals, Inc.)
Melamine resin 10 parts (Super Becamine L-121-60 (solid content 60%), manufactured by Dainippon Ink & Chemicals, Inc.)
2-butanone 100 parts Charge generation layer coating solution Dispersion 1 prepared earlier was used.

Charge transport layer coating solution Polycarbonate (TS2050: manufactured by Teijin Chemicals Ltd.) 10 parts Charge transport material of the following structural formula: 7 parts

80 parts of methylene chloride Photoreceptors 2 to 2 were prepared in the same manner as Photoreceptor Preparation Example 1 except that the charge generation layer coating solution (dispersion 1) used in Photoreceptor Preparation Example 1 was changed to Dispersions 2 to 13, respectively. 13 was produced. In addition, the film thickness of the charge generation layer was adjusted so that the transmittance at 780 nm was 20% when all the coating liquids were used, as in Photoreceptor Preparation Example 1.

(Photoreceptor preparation example 2)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge generation layer coating solution (dispersion 1) used in Photoconductor Preparation Example 1 was changed to Dispersion 2.

(Photoreceptor Preparation Example 3)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge generation layer coating solution (dispersion 1) used in Photoconductor Preparation Example 1 was changed to Dispersion 3.

(Photosensitive member production example 4)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge generation layer coating solution (dispersion 1) used in Photoconductor Preparation Example 1 was changed to Dispersion 4.

(Photoreceptor Preparation Example 5)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge generation layer coating liquid (dispersion 1) used in Photoconductor Preparation Example 1 was changed to Dispersion 5.

(Photosensitive member preparation example 6)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge generation layer coating liquid (dispersion 1) used in Photoconductor Preparation Example 1 was changed to Dispersion 6.

(Photoreceptor Preparation Example 7)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge generation layer coating solution (dispersion 1) used in Photoconductor Preparation Example 1 was changed to Dispersion 7.

(Photoreceptor Preparation Example 8)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge generation layer coating solution (dispersion 1) used in Photoconductor Preparation Example 1 was changed to Dispersion 8.

(Photoreceptor Preparation Example 9)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge generation layer coating solution (dispersion 1) used in Photoconductor Preparation Example 1 was changed to Dispersion 9.

(Photoreceptor Preparation Example 10)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge generation layer coating solution (dispersion 1) used in Photoconductor Preparation Example 1 was changed to Dispersion 10.

(Photoreceptor Preparation Example 11)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge generation layer coating liquid (dispersion 1) used in Photoconductor Preparation Example 1 was changed to Dispersion 11.

(Photoconductor Preparation Example 12)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge generation layer coating solution (dispersion 1) used in Photoconductor Preparation Example 1 was changed to Dispersion 12.

(Photoreceptor Preparation Example 13)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge generation layer coating solution (dispersion 1) used in Photoconductor Preparation Example 1 was changed to Dispersion 13.

<Preparation of Black Toner Developer K-1>
(Black toner)
Polyester resin 95 parts Carbon black 10 parts Salicylic acid derivative zinc salt 2 parts A mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle size of 8.0 µm.

  Further, 2 parts by weight of polyvinyl alcohol and 60 parts by weight of water were placed in a ball mill with respect to 100 parts by weight of magnetite produced by a wet method, and mixed for 12 hours to prepare a magnetite slurry. This slurry was sprayed and granulated with a spray dryer to obtain spherical particles. The particles were fired in a nitrogen atmosphere at a temperature of 1000 ° C. for 3 hours and then cooled to obtain core particles 1.

Silicone resin solution 100 parts Toluene 100 parts γ-aminopropyltrimethoxysilane 15 parts Carbon black 20 parts The above mixture was dispersed with a homomixer for 20 minutes to prepare a coating layer forming liquid 1. The coating layer forming liquid 1 was coated on the surface of 1000 parts of the core particles 1 using a fluid bed type coating apparatus to obtain a silicone resin-coated carrier (magnetic carrier).

  To the toner, titanium oxide fine particles 0.9 wt% and silica fine particles 0.9 wt% (both to the toner) were externally added.

  The magnetic carrier was mixed with 97.5 parts of toner at a ratio of 2.5 parts of toner to prepare a black toner two-component developer (K-1).

  Each of the electrophotographic photoreceptors of Preparation Examples 1 to 13 prepared as described above is mounted on the image forming apparatus shown in FIG. 1, and the surface of the photoreceptor is set to −900 V using a scorotron charging member. Charging is performed, the image exposure light source is a semiconductor laser of 780 nm (image writing by a polygon mirror, resolution 600 dpi), and development is performed by two-component development using the black toner developer (K-1) prepared earlier, and a transfer member A transfer belt (directly transferring a toner image onto a transfer paper) was used, and a 780 nm LED was used for the charge removal light, and the entire surface of the photoconductor was irradiated with light to perform charge removal. Using a chart with a writing rate of 6%, continuous 100,000 sheets were printed as Examples 1 to 3 and Comparative Examples 1 to 10 (the test environment is 22 ° C.-55% RH).

  On the surface of the photoconductor, zinc stearate was supplied for three rotations of the photoconductor every 100 image outputs by a mechanism as shown in FIG. At this time, as a mechanism for bringing zinc stearate into contact with the brush-like structural member, a contact / separation mechanism was used to bring the solidified zinc stearate into contact with the brush-like structural member only when necessary.

  The following two evaluations were carried out after printing 100,000 sheets of images.

(I) Evaluation of soiling:
A white solid image was output, and rank evaluation was performed from the number and size of black spots generated on the background.

(Ii) Evaluation of dot formation state A halftone image (one dot image having a diameter of 60 μm) was formed, and the dot formation state was observed (dot scattering state and dot reproducibility).

  In any case, the rank evaluation was performed in 4 stages, and very good ones were indicated by ◎, good ones by ○, slightly inferior by Δ, and very bad by x. The results are shown in Table 4.

  In Examples 1 to 3 and Comparative Examples 1 to 10, evaluation was performed in the same manner as Examples 1 to 3 and Comparative Examples 1 to 10, except that zinc stearate was not supplied. It was. The results are shown in Table 4.

Since the images of Comparative Examples 11 to 23 had a lower transfer rate than the images of Examples 1 to 3 and Comparative Examples 1 to 10, the image density was lower. Further, with respect to the degree of concentration of toner for forming dots, in Comparative Examples 11 to 23, there were some missing points.

  Photoconductors were prepared in the same manner as in Photoconductor Preparation Examples 1 to 13, except that the aluminum cylinder used in Photoconductor Preparation Examples 1 to 13 was changed to one having a diameter of 60 mm.

  Each of the electrophotographic photosensitive members of Preparation Examples 14 to 26 manufactured as described above is mounted on the image forming apparatus shown in FIG. 1, and the following charging conditions are used using a contact type charging member (charging roller having a diameter of 18 mm). To charge the surface of the photosensitive member to −900 V, the image exposure light source is a semiconductor laser of 780 nm (image writing by a polygon mirror, resolution 600 dpi), and the black toner developer (K-1) prepared earlier is used. The two-component development is used, a transfer belt (directly transferring the toner image onto the transfer paper) is used as a transfer member, a 780 nm LED is used for the charge removal light, and the entire surface of the photoconductor is irradiated with light to perform charge removal. I made it. Using a chart with a writing rate of 6%, continuous 50,000 sheets were printed as Examples 4 to 6 and Comparative Examples 24 to 33 (the test environment is 22 ° C.-55% RH).

  Further, zinc stearate was supplied to the surface of the photoconductor for 3 rotations of the photoconductor every 100 image outputs by a mechanism as shown in FIG. At this time, as a mechanism for bringing zinc stearate into contact with the brush-like structural member, a contact / separation mechanism was used to bring the solidified zinc stearate into contact with the brush-like structural member only when necessary.

Charging conditions:
DC bias: -1600V
The following two evaluations were performed after printing 50,000 sheets.

(I) Evaluation of soiling:
A white solid image was output, and rank evaluation was performed from the number and size of black spots generated on the background.

(Ii) Evaluation of dot formation state:
A halftone image (one dot image having a diameter of 60 μm) was formed, and the dot formation state was observed (dot scattering state and dot reproducibility).

  In each evaluation, a four-level rank evaluation was performed, and an extremely good one was indicated by ◎, a good one by ○, a slightly inferior by Δ, and a very bad one by ×. The results are shown in Table 5.

  In Examples 4 to 6 and Comparative Examples 24 to 33, evaluation was performed in the same manner as Examples 4 to 6 and Comparative Examples 24 to 33, except that zinc stearate was not supplied. . The results are shown in Table 5.

<Preparation of Black Toner Developer K-2>
(Black toner)
Polyester resin 100 parts Carbon black 10 parts Salicylic acid derivative zinc salt 2 parts A mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle size of 7.5 µm.

  To the toner, titanium oxide fine particles 0.9 wt%, silica fine particles 0.9 wt%, and zinc stearate 0.2 wt% (both to the toner) were externally added. A black toner two-component developer (K-2) was prepared by mixing 2.5 parts of the toner with 97.5 parts of the magnetic carrier.

(Example 7)
Evaluation was performed in the same manner as in Comparative Example 19 except that the developer used in Comparative Example 19 was changed to the black toner two-component developer (K-2). The results are shown in Table 6.

(Example 8)
In Example 1, the evaluation was performed in the same manner as in Example 1 except that the chart used in the test was changed to that shown in FIG. The results are shown in Table 6.

Example 9
In Example 7, the evaluation was performed in the same manner as in Example 7 except that the chart used in the test was changed to that shown in FIG. The results are shown in Table 6.

(Example 10)
Evaluation was performed in the same manner as in Example 8 except that the developer used in Example 8 was changed to the black toner two-component developer (K-2). The results are shown in Table 6.

(Example 11)
In Example 4, the evaluation was performed in the same manner as in Example 4 except that the evaluation environment (environment in which the image device was installed) was changed to 28 ° C.-80% RH. The results are shown in Table 7.

(Example 12)
In Example 11, the periphery of the charging member is changed to a structure having a shield as shown in FIG. 3, and air at 23 ° C.-40% RH is 0.2 L / min in the shield during the operation of the image forming apparatus. And the humidity in the shield was evaluated to be 50% RH or less (maintained at 40 to 45% RH). The results are shown in Table 7.

(Example 13)
In Example 11, the periphery of the charging member is changed to a structure having a shield as shown in FIG. 3, and air at 40 ° C.-30% RH is 0.2 L / min in the shield during the operation of the image forming apparatus. And the humidity in the shield was evaluated to be 50% RH or less (35 to 38 ° C., maintained at 40 to 45% RH). The results are shown in Table 7.

(Example 14)
Example 11 is the same as Example 11 except that a drum heater is installed inside the photoconductor and the surface temperature of the photoconductor is controlled to be 40 ° C. ± 1 ° C. (relative humidity near the photoconductor is about 42% RH). Evaluation was performed in the same manner as above. The results are shown in Table 7.

(Example 15)
In Example 1, the chart used for the paper passing test was changed to a chart with a writing rate of 1%, and continuous printing of 50,000 sheets was performed. At this time, in order to measure the photosensitive member surface potential at the developing portion of the image forming apparatus shown in FIG. 3 and the photosensitive member surface potential immediately after the transfer, the surface potential meter was modified so that it could be set.

  Before and after the paper passing test, the potential of the exposed portion of the photoreceptor at the development site was measured. At this time, in order to measure the surface potential of the exposed portion, the optical writing was performed on the entire surface of the photoconductor.

  In the paper passing test in Example 15, the transfer bias was adjusted so that the potential of the non-written portion of the photoconductor after transfer was −150V. In this measurement, optical writing was not performed, and the potential after transfer of the photosensitive member was measured. The results are shown in Table 8.

(Example 16)
The test was performed in the same manner as in Example 15 except that the potential of the non-written portion of the photoconductor after transfer was adjusted to −80 V in Example 15. The results are shown in Table 8.

(Example 17)
In Example 15, the test was performed in the same manner as in Example 15 except that the potential of the non-written portion of the photoconductor after transfer was adjusted to 0V. The results are shown in Table 8.

(Example 18)
The test was performed in the same manner as in Example 15 except that the potential of the non-written portion of the photoconductor after transfer was adjusted to +70 V in Example 15. The results are shown in Table 8.

(Example 19)
The test was performed in the same manner as in Example 15 except that the potential of the non-written portion of the photoconductor after transfer was adjusted to +150 V in Example 15. The results are shown in Table 8.

(Photoconductor Preparation Example 27)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 9 except that the charge transport layer coating solution in Photoconductor Preparation Example 9 was changed to one having the following composition. Charge transport layer coating solution 10 parts of polymer charge transport material having the following composition (weight average molecular weight: about 135,000)

0.5 parts of additive with the following structure

100 parts of methylene chloride (Photoconductor Preparation Example 28)
Similar to Photoreceptor Preparation Example 9 except that the thickness of the charge transport layer in Photoreceptor Preparation Example 9 was 22 μm, a protective layer coating solution having the following composition was applied and dried on the charge transport layer, and a protective layer of 5 μm was provided. A photoreceptor was prepared.

Protective layer coating solution Polycarbonate (TS2050: manufactured by Teijin Chemicals Ltd.) 10 parts Charge transport material of the following structural formula: 7 parts

4 parts of alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.4 μm)
Cyclohexanone 500 parts Tetrahydrofuran 150 parts (Photoconductor Preparation Example 29)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 28 except that the alumina fine particles in the protective layer coating solution in Photoconductor Preparation Example 28 were changed to the following.

4 parts of titanium oxide fine particles (specific resistance: 1.5 × 10 ¹⁰ Ω · cm, average primary particle size: 0.5 μm)
(Photoreceptor Preparation Example 30)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 28 except that the alumina fine particles in the protective layer coating solution in Photoconductor Preparation Example 28 were changed to the following.

4 parts of tin oxide-antimony oxide powder (specific resistance: 10 ⁶ Ω · cm, average primary particle size 0.4 μm)
(Photoreceptor Preparation Example 31)
An electrophotographic photosensitive member was prepared in the same manner as in the photosensitive member preparation example 28 except that the protective layer coating solution in the photosensitive member preparation example 28 was changed to one having the following composition.

Protective layer coating solution 17 parts of polymer charge transport material having the following structural formula (weight average molecular weight: about 135,000)

4 parts of alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.4 μm)
Cyclohexanone 500 parts Tetrahydrofuran 150 parts (Photoconductor Preparation Example 32)
An electrophotographic photosensitive member was prepared in the same manner as in the photosensitive member preparation example 28 except that the protective layer coating solution in the photosensitive member preparation example 28 was changed to one having the following composition.

Protective layer coating solution Methyltrimethoxysilane 100 parts 3% acetic acid 20 parts 35 parts of charge transport compound with the following structure

Antioxidant (Sanol LS2626: Sankyo Chemical Co., Ltd.) 1 part Curing agent (dibutyltin acetate) 1 part 2-propanol 200 parts (Photoconductor Preparation Example 33)
An electrophotographic photosensitive member was prepared in the same manner as in the photosensitive member preparation example 28 except that the protective layer coating solution in the photosensitive member preparation example 28 was changed to one having the following composition.

Protective layer coating solution Methyltrimethoxysilane 100 parts 3% acetic acid 20 parts 35 parts of charge transport compound with the following structure

α-alumina particles (Sumicorundum AA-03: manufactured by Sumitomo Chemical Co., Ltd.) 15 parts Antioxidant (Sanol LS2626: manufactured by Sankyo Chemical Co., Ltd.) 1 part Polycarboxylic acid compound BYK P104: manufactured by BYK Chemie 0.4 part Curing agent (dibutyl) Tin acetate) 1 part 2-propanol 200 parts (Photoconductor Preparation Example 34)
The aluminum cylinder (JIS1050) in photoreceptor preparation example 9 was subjected to the following anodic oxide film treatment, and then a charge generation layer and a charge transport layer were provided in the same manner as photoreceptor preparation example 1 without providing an undercoat layer. Was made.

Anodized film treatment After mirror polishing of the support surface, degreasing and water washing, immersion in an electrolytic bath with a liquid temperature of 20 ° C and sulfuric acid of 15 vol%, and anodizing film treatment for 30 minutes at an electrolysis voltage of 15V. I did it. Further, after washing with water, sealing treatment was performed with a 7% nickel acetate aqueous solution (50 ° C.). Thereafter, the substrate was washed with pure water to obtain a support on which a 7 μm anodic oxide film was formed.

  As described above, the electrophotographic photoreceptors produced in the photoreceptor preparation examples 27 to 34 are each mounted on the image forming apparatus shown in FIG. 1, and the surface of the photoreceptor is set to −900 V using a scorotron charging member. Charging is performed, the image exposure light source is a semiconductor laser of 780 nm (image writing by a polygon mirror, resolution 600 dpi), and development is performed by two-component development using the black toner developer (K-1) prepared earlier, and a transfer member A transfer belt was used, and a 780 nm LED was used for the charge removal light, and the entire surface of the photoconductor was irradiated with light to perform charge removal. Using a chart with a writing rate of 6%, continuous 100,000 sheets were printed as Examples 20 to 27 (the test environment is 22 ° C.-55% RH).

  On the surface of the photoconductor, zinc stearate was supplied for three rotations of the photoconductor every 100 image outputs by a mechanism as shown in FIG.

  The following two evaluations were carried out after printing 100,000 sheets of images.

(I) Evaluation of soiling:
A white solid image was output, and rank evaluation was performed from the number and size of black spots generated on the background.

(Ii) Evaluation of dot formation state:
A halftone image (one-dot image with a diameter of 60 μm) was formed, and the dot formation state was observed (dot dispersion and dot reproducibility)
In any case, the rank evaluation was performed in 4 stages, and very good ones were indicated by ◎, good ones by ○, slightly inferior by Δ, and very bad by x. In addition, the amount of abrasion of the photosensitive layer after printing 100,000 sheets (when the protective layer is provided, the amount of abrasion of the protective layer) was measured. The results are shown in Table 9 together with the case of Example 1.

(Photoconductor Preparation Example 35)
The aluminum cylinder of the photoreceptor preparation example 1 was changed to one having a diameter of 60 mm, and a photoreceptor having the same composition as that of the photoreceptor preparation example 1 was prepared.

(Photoconductor Preparation Example 36)
The aluminum cylinder of the photoreceptor preparation example 4 was changed to one having a diameter of 60 mm to prepare a photoreceptor having the same composition as the photoreceptor preparation example 4.

(Photoreceptor Preparation Example 37)
The aluminum cylinder of photoconductor preparation example 5 was changed to one having a diameter of 60 mm, and a photoconductor having the same composition as photoconductor preparation example 5 was prepared.

(Photoconductor Preparation Example 38)
The aluminum cylinder of the photoreceptor preparation example 8 was changed to one having a diameter of 60 mm, and a photoreceptor having the same composition as that of the photoreceptor preparation example 8 was prepared.

(Photoconductor Preparation Example 39)
The aluminum cylinder of the photoreceptor preparation example 9 was changed to one having a diameter of 60 mm, and a photoreceptor having the same composition as that of the photoreceptor preparation example 9 was prepared.

(Photoconductor Preparation Example 40)
A photoconductor having the same composition as the photoconductor production example 10 was produced by changing the aluminum cylinder of the photoconductor production example 10 to one having a diameter of 60 mm.

<Preparation of Yellow Toner Developer Y-1>
(Yellow toner)
Polyester resin 95 parts C.I. I. Pigment Yellow 180 5 parts Salicylic acid derivative zinc salt 2 parts A mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle diameter of 8.0 μm. To the toner, titanium oxide fine particles 0.9 wt% and silica fine particles 0.9 wt% (both to the toner) were externally added. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier to prepare a yellow toner two-component developer (Y-1).

<Preparation of Magenta Toner Developer M-1>
(Magenta toner)
Polyester resin 95 parts C.I. I. Pigment Red 57: 1 5 parts Salicylic acid derivative zinc salt 2 parts A mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle size of 8.0 µm. To the toner, titanium oxide fine particles 0.9 wt% and silica fine particles 0.9 wt% (both to the toner) were externally added. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier to prepare a magenta toner two-component developer (M-1).

<Preparation of Cyan Toner Developer C-1>
(Cyan toner)
Polyester resin 95 parts C.I. I. Pigment Blue 15: 3 5 parts Salicylic acid derivative zinc salt 2 parts A mixture having the above composition was melt-kneaded and then pulverized and classified to obtain a toner having an average particle diameter of 8.0 µm. To the toner, titanium oxide fine particles 0.9 wt% and silica fine particles 0.9 wt% (both to the toner) were externally added. 2.5 parts of this toner was mixed with 97.5 parts of the above magnetic carrier to prepare a cyan toner two-component developer (C-1).

  The photoconductors of photoconductor preparation examples 35 to 40 manufactured as described above are mounted on a single process cartridge for an image forming apparatus as shown in FIG. 5 together with a charging member (scorotron charging). The full-color image forming apparatus shown in FIG. In the four image forming elements, a charging member is charged by a scorotron charging member so that the surface potential of the photosensitive member becomes −900 V, and an image exposure light source is a semiconductor laser of 780 nm (image writing by a polygon mirror, resolution 600 dpi). For the development, the previously prepared black toner developer (K-1), yellow toner developer (Y-1), magenta toner developer (M-1), and cyan toner developer (C-1) are used. Two-component development was performed, and a continuous belt was printed as Examples 28 to 29 and Comparative Examples 47 to 50 using a transfer belt as a transfer member and a chart with a writing rate of 6% (the test environment was 22). C-55% RH).

  Further, zinc stearate was supplied to the surface of the photoconductor for 3 rotations of the photoconductor every 100 image outputs by a mechanism as shown in FIG.

  The following three evaluations were performed after printing 50,000 sheets.

(I) Evaluation of soiling:
A white solid image was output, and rank evaluation was performed from the number and size of black spots generated on the background.

(Ii) Evaluation of dot formation state A halftone image (one dot image having a diameter of 60 μm) was formed, and the dot formation state was observed (dot scattering state and dot reproducibility).

(Iii) Evaluation of color reproducibility After the photoconductor initial state and 50,000 sheets running, the same full color image was output, and evaluation of color reproducibility was attempted.

  In each evaluation, a four-level rank evaluation was performed, and an extremely good one was indicated by ◎, a good one by ○, a slightly inferior by Δ, and a very bad one by ×. Table 8 shows the above results.

  In Examples 28 to 29 and Comparative Examples 47 to 50, evaluation was performed as Comparative Examples 51 to 56 in the same manner as Examples 28 to 29 and Comparative Examples 47 to 50, except that zinc stearate was not supplied. The results are shown in Table 10.

Finally, 7.3 ° which is the lowest angle peak of the Bragg angle θ, which is a feature of the titanyl phthalocyanine crystal used in the present invention, will be verified as to whether or not it is the same as the lowest angle 7.5 ° of known materials.

(Comparative Synthesis Example 9)
A titanyl phthalocyanine crystal was obtained in the same manner as in Comparative Synthesis Example 1 except that the crystal conversion solvent in Comparative Synthesis Example 1 was changed from methylene chloride to 2-butanone.

  As in Comparative Synthesis Example 1, the XD spectrum of the titanyl phthalocyanine crystal produced in Comparative Synthesis Example 9 was measured. This is shown in FIG. From FIG. 17, the lowest angle in the XD spectrum of the titanyl phthalocyanine crystal produced in Comparative Synthesis Example 9 is 7.5 ° different from the lowest angle (7.3 °) of the titanyl phthalocyanine produced in Comparative Synthesis Example 1. It can be seen that it exists.

(Measurement Example 1)
3% by weight of the pigment obtained in Comparative Synthesis Example 1 (minimum angle 7.3 °) prepared in the same manner as the pigment described in Patent Document 17 (having a maximum diffraction peak at 7.5 °) was added, The mixture was mixed in a mortar, and the X-ray diffraction spectrum was measured as before. The X-ray diffraction spectrum of Measurement Example 1 is shown in FIG.

(Measurement example 2)
3% by weight of the pigment prepared in Comparative Synthesis Example 9 (minimum angle 7.5 °) prepared in the same manner as the pigment described in Patent Document 17 (having a maximum diffraction peak at 7.5 °) was added, The mixture was mixed in a mortar, and the X-ray diffraction spectrum was measured as before. The X-ray diffraction spectrum of Measurement Example 2 is shown in FIG.

  In the spectrum of FIG. 19, it can be seen that there are two independent peaks at 7.3 ° and 7.5 ° on the lower angle side, and at least the peaks at 7.3 ° and 7.5 ° are different. . On the other hand, in the spectrum of FIG. 18, the low angle side peak exists only at 7.5 °, which is clearly different from the spectrum of FIG.

From the above, it can be seen that the minimum angle peak of 7.3 ° in the titanyl phthalocyanine crystal of the present invention is different from the 7.5 ° peak in the known titanyl phthalocyanine crystal.

1 is a schematic view for explaining an electrophotographic process and an image forming apparatus of the present invention. It is a figure showing an example of the mechanism which supplies an additive to the photoreceptor surface. It is the figure which showed an example of the charging member which has the shield which covers a charging nip. 1 is a schematic view for explaining a tandem-type full-color image forming apparatus of the present invention. FIG. FIG. 4 is a diagram for explaining a process cartridge for an image forming apparatus according to the present invention. It is a TEM image of amorphous titanyl phthalocyanine. It is a TEM image of titanyl phthalocyanine after crystal conversion. It is a TEM image of a titanyl phthalocyanine crystal that has undergone crystal conversion in a short time. It is a figure which shows the state of the dispersion liquid when dispersion time is short. It is a figure which shows the state of the dispersion liquid when dispersion time is long. It is a figure which shows an average particle diameter and a particle size distribution about the dispersion liquid of FIG. It is a figure showing the layer structure of the electrophotographic photosensitive member used for this invention. It is a figure showing the layer structure of another electrophotographic photosensitive member used for this invention. 4 is a diagram showing an XD spectrum of titanyl phthalocyanine synthesized in Comparative Synthesis Example 1. FIG. It is a figure showing the XD spectrum of the dry powder of the water paste. The test chart used for Examples 8-10 is shown. 14 is a diagram illustrating an XD spectrum of titanyl phthalocyanine synthesized in Comparative Synthesis Example 9. FIG. It is a figure showing the XD spectrum of the titanyl phthalocyanine used in the measurement example 1. It is a figure showing the XD spectrum of the titanyl phthalocyanine used in the measurement example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Static elimination lamp 3 Charging charger 5 Image exposure part 6 Development unit 8 Registration roller 9 Transfer paper 10 Transfer charger 11 Separation charger 12 Separation claw 13 Additive supply member 14 Fur brush 15 Cleaning blade 16Y, 16M, 16C, 16K Body 17Y, 17M, 17C, 17K Charging member 18Y, 18M, 18C, 18K Laser light 19Y, 19M, 19C, 19K Developing member 20Y, 20M, 20C, 20K Cleaning member 21Y, 21M, 21C, 21K Transfer brush 22 Transfer conveying belt 23 Registration roller 24 Fixing device 25Y, 25M, 25C, 25K Image forming element 26 Transfer paper 27Y, 27M, 27C, 27K Additive supply member 31 Conductive support 35 Charge generation layer 37 Charge transport layer 39 Retention Layer 40 Photoconductor 41 Brush-like structural member 42 Solidified additive 43 Blade-like structural member 44 Developing member 45 Charging member 46 Photoconductor 47 Charging member 48 Shield 49 Gas introduction part 101 Photoconductor 102 Charging means 103 Exposure 104 Developing means 105 Transfer body 106 Transfer means 107 Cleaning means 108 Neutralization means 109 Additive supply member

Claims (33)

  In an image forming apparatus having at least a charging unit, an exposure unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member, and having a mechanism for supplying an additive from the outside to the surface of the photosensitive member, the electrophotographic photosensitive member is conductive. 1. An electrophotographic photosensitive member in which at least a charge generation layer and a charge transport layer are laminated in order on a support, and a diffraction peak (± 0 .0) with a Bragg angle 2θ with respect to CuKα rays (wavelength 1.542Å) in the charge generation layer. 2 °) having a maximum diffraction peak at least 27.2 °, and further having main peaks at 9.4 °, 9.6 °, and 24.0 °, and the lowest diffraction peak. An average size of a primary particle having a peak at 7.3 °, no peak between the peak at 7.3 ° and the peak at 9.4 °, no peak at 26.3 °, and Titanyl phthalocyanate with a 0.25 μm or less An image forming apparatus comprising a down crystal.   Dispersion was performed until the average particle size of the titanyl phthalocyanine crystal particles was 0.3 μm or less and the standard deviation thereof was 0.2 μm or less, and then filtered using a filter having an effective pore size of 3 μm or less. The image forming apparatus according to claim 1, wherein a charge generation layer is applied.   The titanyl phthalocyanine crystal has a maximum diffraction peak at 7.0 to 7.5 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα, Crystal transformation of amorphous titanyl phthalocyanine or low crystalline titanyl phthalocyanine having an average primary particle size of 0.1 μm or less with a half-width of the diffraction peak of 1 ° or more in an organic solvent in the presence of water. The titanyl phthalocyanine after crystal conversion from an organic solvent is prepared by fractionation and filtration before the average particle size of the subsequent primary particles grows larger than 0.25 μm. Image forming apparatus.   The image forming apparatus according to claim 1, wherein the titanyl phthalocyanine crystal is synthesized using a raw material not containing a halide.   When the titanyl phthalocyanine crystal is converted, the amorphous titanyl phthalocyanine used is prepared by the acid paste method, and the pH after washing of ion-exchanged water used for washing is between 6 and 8 and / or the specific conductivity is 8 μS. The image forming apparatus according to claim 3, wherein the image forming apparatus has a physical property value of not more than / cm.   6. The image forming apparatus according to claim 3, wherein the amount of the organic solvent used in the crystal conversion of the titanyl phthalocyanine crystal is 30 times or more that of the amorphous titanyl phthalocyanine by weight ratio.   7. The image forming apparatus according to claim 1, wherein the charge transport layer contains at least a polycarbonate having a triarylamine structure in the main chain and / or side chain.   The image forming apparatus according to claim 1, further comprising a protective layer on the charge transport layer. The image forming apparatus according to claim 8, wherein the protective layer contains an inorganic pigment or metal oxide having a specific resistance of 10 ¹⁰ Ω · cm or more.   The image forming apparatus according to claim 8, wherein the protective layer contains a polymer charge transport material.   The image forming apparatus according to claim 8, wherein the binder resin of the protective layer has a crosslinked structure.   The image forming apparatus according to claim 11, further comprising a charge transporting site in a structure of the binder resin having the cross-linked structure.   13. The image forming apparatus according to claim 1, wherein a surface of a conductive support of the electrophotographic photosensitive member is anodized.   The image forming apparatus according to claim 1, wherein the supply of the additive is performed by a member in contact with the photosensitive member.   15. The image forming apparatus according to claim 1, wherein the additive supply member is a brush-like structural member.   The image forming apparatus according to claim 1, wherein the additive supply member is an image forming developing member.   The image forming apparatus according to claim 15, wherein any two or more of the brush-like structural member or the developing member and the blade-like member are used in combination.   15. The image forming apparatus according to claim 1, wherein the supply of the additive uses both the supply from the brush-like structural member and the supply from the developing member.   2. A contact / separation mechanism is provided on the supply member of the additive, and when the photosensitive member is not charged from the charging member, the photosensitive member is separated from the photosensitive member and contacted only when charging is performed. The image forming apparatus according to claim 18.   The image forming apparatus according to claim 1, wherein the additive is at least one selected from waxes and lubricants.   The image forming apparatus according to claim 20, wherein the additive is zinc stearate.   The charging member includes a shield having a shape covering at least a charging nip formed between the charging member and the photosensitive member, and the relative humidity of the atmosphere in the charging nip is maintained at 50% RH or less. The image forming apparatus according to claim 1.   23. The image according to claim 22, wherein in the image forming apparatus, a gas having a relative humidity of 50% RH or less is introduced into the shield to control the relative humidity of the atmosphere in the charging nip to 50% RH or less. Forming equipment.   24. The image forming apparatus according to claim 22, wherein a gas having a temperature higher than room temperature is introduced into the shield to control the relative humidity of the atmosphere in the charging nip to 50% RH or less. The image forming apparatus described.   23. The image forming apparatus according to claim 1, wherein a drum heater is installed inside the photosensitive member, and the relative humidity of the atmosphere in the charging nip is controlled to 50% RH or less. .   26. The image forming apparatus according to claim 1, wherein the transfer member used in the image forming apparatus is a direct transfer system that directly transfers a toner image formed on a photoreceptor to a transfer target.   27. The image forming apparatus according to claim 26, wherein the photosensitive member surface potential after transfer in the non-writing portion is 100 V or less as an absolute value of the polarity charged by the main charger. .   27. The image forming apparatus according to claim 26, wherein the surface potential of the photoreceptor after transfer in the non-writing portion is opposite to the polarity charged by the main charger.   29. The image forming apparatus according to claim 28, wherein the photoreceptor surface potential after transfer in the non-writing portion is 100 V or less as an absolute value of the reverse polarity of the polarity charged by the main charger. Image forming apparatus.   30. The image forming apparatus according to claim 1, wherein an optical static elimination mechanism is not used in the image forming apparatus.   31. The image forming apparatus according to claim 1, wherein a plurality of image forming elements including at least a charging unit, an exposure unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member are arranged.   32. The image forming apparatus according to claim 1, wherein an AC superimposed voltage is applied to a charging unit of the electrophotographic apparatus.   33. An apparatus main body and a detachable cartridge on which a photosensitive member and at least one means selected from charging means, exposure means, developing means, and cleaning means are integrated are mounted. The image forming apparatus according to any one of the above.