JP4404358B2 - Electrophotographic photosensitive member, image forming apparatus, and process cartridge for image forming apparatus - Google Patents

Description

  The present invention uses an electrophotographic photosensitive member obtained by sequentially laminating at least a conductive layer, a charge blocking layer, and a photosensitive layer containing a titanyl phthalocyanine crystal having a specific crystal type having an average particle size of 0.25 μm or less. The present invention relates to an image forming apparatus and a process cartridge for the image forming apparatus.

  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 is markedly improved in print quality and reliability. This digital recording technology 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. Further, along 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.

  Such a digital image forming apparatus is required to improve its function year by year, as well as to have high image quality as well as high durability and high stability. Furthermore, in order to achieve high-speed color, a tandem system using a plurality of image forming elements each having one member necessary for image formation such as charging, exposure, development, cleaning, charge removal, etc. attached to one photoconductor. Color image forming apparatuses are currently mainstream. This is usually equipped with image forming elements for yellow, magenta, cyan, and black, and each toner image is produced in parallel with four image forming elements and overlapped on a transfer body (transfer paper) or an intermediate transfer body. Thus, a color image is produced at high speed. For this reason, unless the photosensitive member and the members around it are made compact, the image forming apparatus becomes very large. Therefore, it is essential to reduce the diameter of the photosensitive member arranged at the center of the image forming element. . Even if the image forming apparatus is made compact by reducing the diameter of the photosensitive member, there is no merit of reducing the diameter when the life is extremely shortened compared to the case of a large diameter. For this reason, it is an issue of this technique to extend the life of the photoconductor as compared to the conventional photoconductor.

  There are two rate-limiting processes in the life of the photoreceptor, one is electrostatic fatigue and the other is wear of the surface layer. Both are major problems for the current mainstream organic photoreceptors. The former is a change in the surface potential (charge potential and exposed portion potential) of the photoreceptor during repeated use in image formation such as charging and exposure. When organic materials are used, the charged potential decreases or the exposed portion potential increases. (Sometimes called residual potential) is a problem. The latter is a phenomenon in which a layer located on the outermost surface constituting the photoconductor is mechanically worn by rubbing of a cleaning member or the like. When the film thickness of the photoreceptor surface layer decreases due to this wear, scratches on the surface, an increase in electric field strength due to a decrease in the film thickness of the photoreceptor layer, acceleration of electrostatic fatigue, and the like are caused, and the life of the photoreceptor is significantly reduced. It becomes a factor. Therefore, in order to improve the life of the photoreceptor, the above two problems must be solved at the same time.

  At present, electrophotographic image forming apparatuses are entering the printing field by realizing high speed, and high image quality and high stability are demanded. Regarding the former, 600 dpi is the lowest quality as the resolution in image writing, and the resolution has been greatly improved. In the latter, taking advantage of the characteristics of electrophotography that can directly print manuscript information, it is possible to add various information that is different one by one to a part of an output manuscript that is good at mass printing. In addition, a large variety of writing and developing operations are performed, in which slightly different information is input one by one at the same time, and stability as a system has been greatly demanded. For these, stability in repeated use of the image forming element is naturally required, and it is extremely important that no abnormal image is generated.

  The life and stability of such an image forming apparatus is the center of image formation, and a photoreceptor that always performs an associated operation with other members during an image forming operation holds the most important key. With all the energetic development of the photoreceptor so far, several techniques are being completed regarding the electrostatic properties and surface wear of the photoreceptor. For example, with regard to improvement of electrostatic characteristics, development of a charge generation material having a high photocarrier generation efficiency and development of a charge transport material having a high mobility can be mentioned. By combining these, it is possible to obtain a large gain and response in light attenuation. As a whole system, the charging potential is reduced, the amount of writing light is reduced, the development bias is reduced, the transfer bias is reduced, and the static elimination process is reduced. It creates unnecessaryness and creates a margin in system design. All of these lead to a reduction in the hazard applied to the photoreceptor, and allowance is also created in the photoreceptor itself.

  However, as described above, the usage of the photoconductor in the analog type image forming apparatus and the monochrome type image forming apparatus is changed by the advent of a high-speed full-color machine, and various ways of optical writing are used. It became so. In such a case, generation of an abnormal image caused by the photoconductor becomes the biggest problem. Although there are various cases of occurrence of abnormal images, they can be roughly divided into two. One is an abnormal image due to scratches or the like generated on the surface of the photoconductor, and the other is an abnormal image generated due to electrostatic fatigue of the photoconductor. The former can be dealt with considerably by improving the surface layer of the photosensitive member (for example, using a protective layer) or by improving the photosensitive member abutting member. The latter is caused by the deterioration of the photosensitive member itself, but the most serious problem at present is background contamination in negative / positive development.

  Causes of scumming are dirt and defects on the conductive support, electrical breakdown of the photosensitive layer, carrier (charge) injection from the support, increased dark decay of the photosensitive member, and generation of thermal carriers in the photosensitive layer. Is mentioned. Of these, the contamination and defects of the support can be dealt with by eliminating such support before applying the photosensitive layer, and in a sense, it is caused by an error. is not. Therefore, improving the withstand voltage of the photoreceptor, the charge injection from the support, and the reduction in electrostatic fatigue is considered to be the fundamental solution to this problem.

  In view of such a point, techniques for providing an undercoat layer or an intermediate layer between a conductive support and a photosensitive layer have been proposed in the past. For example, Patent Document 1 includes a cellulose nitrate resin intermediate layer, Patent Document 2 includes a nylon resin intermediate layer, Patent Document 3 includes a maleic acid resin intermediate layer, and Patent Document 4 includes a polyvinyl alcohol resin intermediate layer. Are each disclosed.

  However, the intermediate layer of these resins alone (single layer) has a high electric resistance, so that a residual potential is generated and image density is lowered in negative / positive development. In addition, since it exhibits ionic conductivity due to impurities and the like, the electrical resistance of the intermediate layer is particularly high under low temperature and low humidity, so that the residual potential is significantly increased. For this reason, it is necessary to reduce the thickness of the intermediate layer, and there is a drawback that the chargeability and charge retention are insufficient in the characteristics after repeated use.

  In order to solve these problems, as a technique for controlling the electric resistance of the intermediate layer, a method of adding a conductive additive to the bulk of the intermediate layer has been proposed. For example, Patent Document 5 includes an intermediate layer in which a carbon or chalcogen-based material is dispersed in a curable resin, and Patent Document 6 includes a thermal polymer intermediate layer using an isocyanate-based curing agent to which a quaternary ammonium salt is added, Patent Document 7 discloses a resin intermediate layer to which a resistance modifier is added, and Patent Document 8 discloses a resin intermediate layer to which an organometallic compound is added. However, these resin intermediate layers alone have a problem that a moire image is generated in an image forming apparatus using coherent light such as laser light in recent years.

  Furthermore, for the purpose of simultaneously controlling the moiré prevention and the electric resistance of the intermediate layer, a photoreceptor containing a filler in the intermediate layer has been proposed. For example, Patent Document 9 includes a resin intermediate layer in which an oxide of aluminum or tin is dispersed, Patent Document 10 includes a resin intermediate layer in which conductive particles are dispersed, and Patent Document 11 includes an intermediate layer in which magnetite is dispersed. Patent Document 12 includes a resin intermediate layer in which titanium oxide and tin oxide are dispersed, Patent Document 13, Patent Document 14, Patent Document 15, Patent Document 16, Patent Document 17, and Patent Document 18 include calcium, magnesium, aluminum, and the like. An intermediate layer of resin in which powders of boride, nitride, fluoride, and oxide are dispersed is disclosed. In the intermediate layer in which such filler is dispersed, the amount of filler in the intermediate layer needs to be increased (that is, the amount of resin needs to be reduced) in order to develop the potential characteristics of the intermediate layer by the dispersed filler. . For this reason, there is a problem in that the adhesiveness with the conductive support decreases with a decrease in the resin amount, and peeling easily occurs between the support and the intermediate layer. In particular, the support is a flexible belt-like structure. This problem is remarkable when

  In order to solve such problems, a concept of stacking intermediate layers has been proposed. The laminated structure is roughly classified into two types. One is a laminate in which a resin layer 2 in which filler is dispersed and a resin layer 3 in which filler is not dispersed are sequentially laminated on the conductive support 1 (see FIG. 1). The other is one in which a resin layer 3 in which a filler is not dispersed and a resin layer 2 in which a filler is dispersed are sequentially provided on a conductive support 1 (see FIG. 2). 1 and 2, reference numeral 4 denotes a photosensitive layer.

  The former configuration will be described in detail. In order to cover the defects of the support as described above, a conductive layer in which a low resistance filler is dispersed is provided on the conductive support, and the resin layer is provided thereon. Is. These are described in, for example, Patent Literature 19, Patent Literature 20, Patent Literature 21, Patent Literature 22, Patent Literature 23, Patent Literature 24, Patent Literature 25, Patent Literature 26, Patent Literature 27, and the like. In these, the conductive layer which is essentially the lower layer plays the role of an electrode in the conductive support, and therefore, the structure of the resin intermediate layer alone and the electrostatic defect of the above-described photoconductor do not change. Only, since the conductive layer is composed of a filler dispersion film, a moire prevention function is imparted by scattering of writing light by this layer. In such a configuration, since the lower layer is a conductive layer, the charge opposite to the polarity charged on the surface of the photosensitive member is charged to the interface between the lower layer (conductive layer) and the upper layer (resin intermediate layer). By reaching, the operation of the photoconductor is established. However, when the resistance of the conductive layer is not so low, charge injection from the electrode is not sufficiently performed, and the lower layer becomes a resistance component during repeated use, resulting in a very high residual potential. In particular, in order to cover defects of the conductive support, which is one of the purposes of this configuration, it is essential to make the lower layer sufficiently thick (10 μm or more), and this problem is remarkable.

  Patent Document 28, Patent Document 29, and Patent Document 30 disclose a photoreceptor in which a conductive layer, an intermediate layer, and a photosensitive layer containing a titanyl phthalocyanine crystal are stacked. However, unless the crystal form and primary particle size of titanyl phthalocyanine are appropriately controlled, the occurrence of scumming due to the influence of heat carriers cannot be reduced.

  On the other hand, as the latter configuration, a hole blocking layer is provided on a conductive support, and a resin layer in which a filler having low resistance or an electron conductive filler is dispersed is provided thereon. These are described in, for example, Patent Document 31, Patent Document 32, and the like. Since this configuration has a hole blocking function similar to the former configuration, it effectively works against background contamination. Further, since the filler-dispersed film is present in the upper layer, the residual potential is less accumulated as compared with the former configuration. In this configuration, as described above, injection of electric charges (holes) from the conductive support to the photosensitive layer can be prevented, so that the background stain phenomenon in negative / positive development can be considerably reduced. Further, by disposing the charge blocking layer in the lower layer, an increase in the residual potential in repeated use can be reduced as compared with the case where it is disposed in the upper layer.

However, in any of the configurations, the cause of soiling is not only the injection of charges (holes) from the conductive support to the photosensitive layer, but also the influence of the generation of heat carriers in the photosensitive layer cannot be ignored. For this reason, unless the charge generation material used in the charge generation layer and the particle state thereof are controlled, the occurrence of scumming in repeated use cannot be completely controlled.
JP-A-47-6341 JP-A-60-66258 JP 52-10138 A JP 58-105155 A JP 51-65942 A JP 52-82238 A Japanese Patent Application Laid-Open No. 55-110451 JP 58-93062 A Japanese Patent Laid-Open No. 58-58556 Japanese Patent Laid-Open No. 60-111255 JP 59-17557 A JP-A-60-32054 JP-A 64-68762 JP-A 64-68763 JP-A 64-73352 JP-A 64-73353 JP-A-1-118848 Japanese Patent Laid-Open No. 1-118849 JP 58-95351 A JP 59-93453 A JP-A-4-170552 JP-A-6-208238 JP-A-6-222600 Japanese Patent Laid-Open No. 8-184979 Japanese Patent Laid-Open No. 9-43886 Japanese Patent Laid-Open No. 9-190005 JP-A-9-288367 Japanese Patent Laid-Open No. 5-100461 Japanese Patent Laid-Open No. 5-210260 Japanese Patent Laid-Open No. 7-271072 Japanese Patent Laid-Open No. 5-80572 JP-A-6-19174

  An object of the present invention is to provide an electrophotographic photosensitive member capable of forming a stable image even when used repeatedly. Specifically, a highly durable electrophotographic photosensitive member capable of reducing the occurrence of scumming during repeated use, preventing residual potential, and reducing the occurrence of dielectric breakdown during charging by a contact charging member or a charging member disposed in the vicinity. It is to provide.

As described above, in recent years, digital image forming apparatuses have been required to have a function capable of forming a high-quality halftone image as an output image from a computer or the like.
A digital image is formed by an array of dot-like images (hereinafter referred to as dots) having a diameter of several tens of μm to about 100 μm. In particular, the halftone is obtained by changing the dot arrangement density and the pixel size. The shade is expressed.

In order to reproduce a higher-definition halftone, the uniformity of the size, shape, and density of each dot forming the halftone image portion is required. Although in the formation of a normal character image not a practical problem, in the halftone image or color image dots are formed regularly arranged, by uneven slight dot, color unevenness of small image portion, the density irregularity As a result, the image becomes rough, and such an image gives the viewer a sense of incongruity and discomfort.

Another object of the present invention is to provide an electrophotographic photosensitive member in which a rough image due to color unevenness and density unevenness in the halftone portion is difficult to occur.
It is another object of the present invention to provide an image forming apparatus that generates less abnormal images even when repeated image formation (output) is performed using the photoconductor. Specifically, an object of the present invention is to provide a highly durable and stable image forming apparatus that solves the greatest problems when using negative / positive development such as background contamination and density reduction. Another object of the present invention is to provide an image forming apparatus that is less dependent on the environment and that can operate stably in any environment.
Furthermore, another object of the present invention is to provide a process cartridge for an image forming apparatus that uses the above-mentioned photoreceptor and is highly durable and easy to handle.

The present inventors have intensively studied a highly durable and highly reliable photoconductor technology for a photoconductor for an image forming apparatus using negative / positive development, and have completed the present invention.
Thus, the above problem is solved by the following configuration of the present invention.
(1) In an electrophotographic photosensitive member in which at least a conductive layer, a charge blocking layer, and a photosensitive layer are sequentially laminated on a conductive support, Bragg against characteristic X-rays (wavelength: 1.542 mm) of CuKα in the photosensitive layer. As a diffraction peak at an angle 2θ (± 0.2 °), it has a maximum diffraction peak at least 27.2 °, and further has main peaks at 9.4 °, 9.6 °, and 24.0 °, Crystal having a peak at 7.3 ° as a diffraction peak on the lowest angle side, no peak between the peak at 7.3 ° and the peak at 9.4 °, and a peak at 26.3 ° Type, containing a titanyl phthalocyanine crystal having an average primary particle size of 0.25 μm or less, and the titanyl phthalocyanine crystal has a Bragg angle 2θ diffraction peak (± 0.2 °) with respect to the characteristic X-ray of CuKα, At least 7 Amorphous titanyl phthalocyanine or low crystalline titanyl phthalocyanine having a maximum diffraction peak at 0.0 to 7.5 ° and an average particle size of primary particles whose half-value width of the diffraction peak is 1 ° or more is 0.1 μm or less Crystal transformation is performed with an organic solvent in the presence of water, and the primary particles after the crystal transformation are fractionated and filtered from the organic solvent before the average particle size grows larger than 0.25 μm. Electrophotographic photoreceptor.

(2) In the titanyl phthalocyanine crystal, the peak intensity at 26.3 ° is in the range of 0.1 to 5% with respect to the peak intensity at the maximum diffraction peak of 27.2 °. The electrophotographic photosensitive member according to Item.
(3) The electrophotographic photosensitive member according to item (1) or (2), wherein the photosensitive layer has a laminated structure of a charge generation layer and a charge transport layer.

(4) The electrophotographic photosensitive film as described in any one of (1) to (3) , wherein the titanyl phthalocyanine crystal is synthesized using a raw material not containing a halide. body.

( 5 ) The electrophotographic photosensitive member according to any one of (1) to (4) , wherein the charge blocking layer is made of an insulating material and has a thickness of less than 2.0 μm. .
( 6 ) The electrophotographic photosensitive member according to (5) , wherein the insulating material is polyamide.

( 7 ) Any of (1) to (6 ) above, wherein the moire preventing layer contains an inorganic pigment and a binder resin, and the volume ratio of the two is in the range of 1/1 to 3/1. The electrophotographic photosensitive member according to one item.
( 8 ) The electrophotographic photosensitive member according to (7) , wherein the binder resin is a thermosetting resin.
( 9 ) The electrophotographic photosensitive member according to (8) , wherein the thermosetting resin is a mixture of alkyd / melamine resin.
( 10 ) The electrophotographic photosensitive member as described in (9) above, wherein the mixing ratio of the alkyd resin and the melamine resin is in the range of 5/5 to 8/2 (weight ratio).

( 11 ) The electrophotographic photosensitive member according to any one of (1) to (10) , wherein a protective layer is provided on the photosensitive layer.
( 12 ) The electrophotographic photosensitive member according to (11) , wherein the protective layer contains an inorganic pigment or metal oxide having a specific resistance of 10 ¹⁰ Ω · cm or more.
( 13 ) The electrophotographic photoreceptor as described in (12) above , wherein the metal oxide is any one of alumina, titanium oxide and silica having a specific resistance of 10 ¹⁰ Ω · cm or more.
( 14 ) The electrophotographic photosensitive member as described in ( 13 ) above , wherein the metal oxide is α-alumina having a specific resistance of 10 ¹⁰ Ω · cm or more.
( 15 ) The electrophotographic photosensitive member according to any one of (11) to (14) , wherein the protective layer contains a polymer charge transport material.
( 16 ) The electrophotographic photosensitive member according to any one of (11) to (14) , wherein the binder resin of the protective layer has a crosslinked structure.

( 17 ) The electrophotographic photosensitive member as described in (16) above, which has a charge transport site in the structure of the binder resin having a crosslinked structure.
( 18 ) In the image forming apparatus comprising at least a charging unit, an exposure unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member, the electrophotographic photosensitive member according to any one of ( 1) to (17). An image forming apparatus, which is the electrophotographic photosensitive member according to claim 1.
( 19 ) The image forming apparatus as described in (18) above, wherein a plurality of image forming elements comprising at least charging means, exposure means, developing means, transfer means, and electrophotographic photosensitive member are arranged.
( 20 ) The image forming apparatus as described in (18) or ( 19 ) above, wherein a contact charging method is used for the charging means of the image forming apparatus.
( 21 ) The image forming apparatus as described in (18) or (19) above, wherein a non-contact proximity arrangement method is used for the charging means of the image forming apparatus.
( 22 ) The image forming apparatus according to (21) , wherein a gap between a charging member used for the charging unit and the photosensitive member is 100 μm or less.

( 23 ) The image forming apparatus according to any one of (20) to (22) , wherein an AC superimposed voltage is applied as a charging unit of the image forming apparatus.
( 24 ) The image forming apparatus includes an apparatus main body in which a photosensitive member and at least one unit selected from a charging unit, an exposure unit, a developing unit, and a cleaning unit are integrated, and a detachable cartridge. The image forming apparatus according to any one of (18) to (23) , characterized in that it is characterized in that:
(25) at least a charging means, exposing means, developing means, and one means selected from the cleaning means, and an electrophotographic photosensitive member in the process cartridge for the image forming apparatus together, the electrophotographic photosensitive member is the first ( A process cartridge for an image forming apparatus, which is the electrophotographic photosensitive member according to any one of 1) to (17) .

Hereinafter, the electrophotographic photosensitive member used in the present invention will be described in detail.
The electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member in which at least a conductive layer, a charge blocking layer, and a photosensitive layer are sequentially 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 has no peak between the 7.3 ° peak and the 9.4 ° peak, and It contains a titanyl phthalocyanine crystal having a peak at 26.3 ° and an average primary particle size of 0.25 μm or less.

  This crystal type is described in JP-A No. 2001-187794. By using this titanyl phthalocyanine crystal, it is stable without causing a decrease in chargeability even after repeated use without losing high sensitivity. An electrophotographic photoreceptor can be obtained. Japanese Patent Application Laid-Open No. 2001-187794 discloses a charge generating material (same crystal type) used in the present invention, a photoreceptor using the same, and an electrophotographic apparatus. However, in the case where it is used at a resolution of 600 dpi or higher or 1200 dpi or higher, when it is used for a very long period of time, it causes scumming and determines the life of the photoreceptor. Such a phenomenon appears remarkably when used in an image forming apparatus that is faster than the image forming apparatus described in the publication. As a result of detailed examination of this phenomenon, the present inventors have found that this phenomenon can be controlled by controlling the particle size of titanyl phthalocyanine. As described above, the photoconductors of the past configuration do not necessarily fully draw out the capabilities of the materials described in the publication.

  On the other hand, the configuration of the intermediate layer in which the conductive layer and the charge blocking layer are laminated in this order between the conductive support and the photosensitive layer is as described above, such as Patent Document 19, Patent Document 20, Patent Document 21, Patent Document 22, and Patent Document. Although it is a technique described in Document 23, Patent Document 24, Patent Document 25, Patent Document 26, Patent Document 27, etc., in combination with a photosensitive layer that can achieve high sensitivity, generation of thermal carriers in the photosensitive layer The influence was great, and it was not always possible to completely prevent scumming. This tendency becomes a significant problem when a charge generating material having absorption at a long wavelength typified by titanyl phthalocyanine as used in the present invention is used.

Therefore, both technologies are incomplete technologies, and a photoconductor having an intermediate layer in which a conductive layer and a charge blocking layer are laminated in this order using a titanyl phthalocyanine crystal having a specific crystal type as described above as a photosensitive layer was produced. In this case, although high sensitivity and electrostatic stability are manifested, the improvement in dirt durability and prevention of dielectric breakdown by the charging member, which are the objects of the present invention, were not satisfactory.
In addition, the above-described photoreceptor using titanyl phthalocyanine as a charge generating material is satisfactory for reducing the density unevenness and roughness of the halftone image or color image of a high-resolution digital image described above. It wasn't.

In the electrophotographic system, a dot image of a digital image is usually formed as follows.
The uniformly charged photoconductor is exposed in a dot shape with laser light or LED light, the electrostatic charge on the surface of the photoconductor is erased, and a dot-shaped electrostatic charge latent image is formed. Next, this latent image is developed with toner to form a dot image. Therefore, the uniformity of the dot image depends on how uniformly each dot-like electrostatic latent image is formed on the surface of the photoreceptor. In order to form a uniform latent image, it is necessary to pay attention to the design of the photoconductor, to make the photosensitivity of the photoconductor uniform. It is to do.

  In particular, in a laminated type photoreceptor in which a photosensitive layer is composed of a charge generation layer and a charge transport layer, the thickness of the charge generation layer is usually a thin layer of 1 μm or less. There is also a small amount of coarse particles formed by agglomeration of charge generating materials and the like, and the particles need to be uniformly distributed. The higher the dot density of the image, the higher the demand. In addition, the higher the photosensitivity of the charge generating material, the more uneven the distribution of the charge generating material will cause the non-uniformity of the dot-like latent image.

  Accordingly, as a result of intensive studies to solve the above-mentioned problems, the present inventors have controlled the particle size of the titanyl phthalocyanine crystal having the specific crystal type to 0.25 μm or less by the following method. It has been found that the object of the present invention can be achieved by further combining such techniques.

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 “Phthalocyanine Compounds” (1963), “The Phthalocyanines” (1983) by Moser et al., JP-A-6-293769, 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.

  As described above, as a method for synthesizing the titanyl phthalocyanine crystal used in the present invention, as described in JP-A-6-293769, a method using no titanium halide as a raw material is preferably used. The biggest merit of this method is that the synthesized titanyl phthalocyanine crystal is free of halogenation. If the titanyl phthalocyanine crystal contains a halogenated titanyl phthalocyanine crystal as an impurity, the electrostatic properties of the photoreceptor using the crystal often have adverse effects such as a decrease in photosensitivity and a decrease in chargeability (Japan Hardcopy '89 paper). (P.103 1989). Also in the present invention, halogenated free titanyl phthalocyanine crystals as described in JP-A-2001-19871 are mainly used, and these materials are effectively used.

Next, a method for synthesizing amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) will be described. This method is a method in which phthalocyanines are dissolved in sulfuric acid, diluted with water and reprecipitated, and what is called an acid paste method or an acid slurry method can be used.
As a specific method, the above synthetic crude product is dissolved in 10-50 times the amount of concentrated sulfuric acid, and if necessary, insoluble matter is removed by filtration or the like, and this is sufficiently cooled to 10-50 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 preferably 8 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. In this case, 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 1.542Å) 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 1.542 mm). Has a major diffraction peak at 9.4 °, 9.6 °, 24.0 °, and the lowest diffraction peak at 7.3 °, And it is a step of converting into 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 amorphous form of the titanyl phthalocyanine (low crystalline titanyl phthalocyanine) is mixed and stirred with an organic solvent in the presence of water without drying, thereby obtaining the crystal form.
In this case, any organic solvent can be used as long as the desired crystal form can be obtained, but 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 the 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 resulting 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, JP-A-8-110649 (comparative example) describes a method for carrying out crystal conversion by introducing titanyl phthalocyanine dissolved in sulfuric acid into an organic solvent together with ion-exchanged water. 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. The method for producing titanyl phthalocyanine of the present invention is not good. The reason for this is as described above.

  The above crystal conversion method is a crystal conversion method according to Japanese Patent Laid-Open No. 2001-19871. In the charge generating material contained in the electrophotographic photosensitive member of the present invention, the effect is expressed by making the particle size of the titanyl phthalocyanine crystal finer. The production method thereof will be described below.

  There are two main methods for controlling the particle size of titanyl phthalocyanine crystals contained in the photosensitive layer. One is a method of synthesizing a crystal containing no particles larger than 0.25 μm when synthesizing titanyl phthalocyanine crystal particles, and the other is a coarse particle larger than 0.25 μm after the titanyl phthalocyanine crystal is dispersed. It is a method to remove. Of course, using both in combination has a greater effect.

First, a method for synthesizing fine-particle titanyl phthalocyanine crystals will be described.
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. 3, the scale bar is 0.2 μm), it was found that during crystal conversion, the crystal is converted as the crystal grows. Usually, in this type of crystal conversion, a sufficient crystal conversion time is secured because of the risk of remaining raw materials, 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. 4, scale bar is 0.2 μm).

  In dispersing the titanyl phthalocyanine crystal thus produced, the dispersion is performed by giving a strong share in order to reduce the particle size after dispersion (0.25 μm or less, preferably 0.2 μm or less). You can also. Further, if necessary, dispersion can be performed by applying strong energy for pulverizing the primary particles. However, such dispersion is not preferable because a part of the particles are transferred to a crystal form that is not a desired crystal form.

  On the other hand, in the present invention, the range in which crystal growth hardly occurs at the time of crystal conversion (the size of the amorphous titanyl phthalocyanine particles observed in FIG. 3 is kept in a small size, approximately 0.25 μm or less after crystal conversion. In other words, it is intended to obtain a titanyl phthalocyanine crystal having the smallest primary particle size as much 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 strong to sufficiently contact the solvent and titanyl phthalocyanine aqueous paste (raw material prepared as described above: amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine)) in order to complete the crystal conversion in a short time. Stirring is used. 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. As a result, 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, a large amount of a solvent that hardly causes crystal conversion is immediately added 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 (pigment filtration step) for producing the titanyl phthalocyanine pigment, the dispersion liquid In view of the dispersion stability of, 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. Therefore, the suitable particle size of the pigment particles is in the range of about 0.05 μm to 0.2 μm.

FIG. 5 shows a TEM image of the titanyl phthalocyanine crystal when the crystal conversion is performed in a short time (the scale bar in the figure is 0.2 μm). Unlike the case of FIG. 4, the particle size is small and almost uniform, and no coarse particles as observed in FIG. 4 are observed.
In dispersing the titanyl phthalocyanine crystal thus produced, since the primary particles of the titanyl phthalocyanine after synthesis are small, it is not necessary to give a strong share to disperse the titanyl phthalocyanine containing coarse particles as shown in FIG. Desired dispersion (the average particle size is 0.25 μm or less, preferably 0.2 μm or less) is possible. As a result, as described above, a part of the particles is not easily transferred to a crystal form which is not a desired crystal form due to excessive dispersion.

  The average 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.

6 and 7 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. 6, and it is observed that coarse particles remain as compared with FIG. 7 having a long dispersion time. The black particles in FIG. 6 are coarse particles.
The average particle size and particle size distribution of these two types of dispersions were measured by 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. 8 corresponds to the dispersion shown in FIG. 6, 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, no difference is recognized between the two.

Therefore, it is understood that the remaining of a minute amount of coarse particles cannot be detected only by the definition of the known average particle size (average 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 select a suitable crystal conversion solvent as described above and complete the crystal conversion in a short time while improving the crystal conversion efficiency, a solvent and a titanyl phthalocyanine water paste (raw materials 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 average particle size (0.25 μm or less, preferably 0.2 μm or less) can be obtained. In addition to the technique described in Japanese Patent Application Laid-Open No. 2001-187794, using the above-described technique (crystal conversion method for obtaining a fine titanyl phthalocyanine crystal) in combination with the effect of the present invention as necessary. It is an effective means to increase.

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 heat drying, but a blower-type dryer is preferred 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, the second crystal conversion method will be described. The second crystal conversion is a step of further crystal conversion using the titanyl phthalocyanine crystal (dry powder) produced by the first crystal conversion. Specific methods include two types of methods.
One is a method of treating the previously prepared titanyl phthalocyanine crystal in an organic solvent. The organic solvent used is a solvent that can convert a crystal form having a maximum diffraction peak at 27.2 ° and no peak at 26.3 ° into a crystal form having a diffraction peak at 26.3 °. Any one can be used, but aromatic hydrocarbons such as toluene and xylene, ketones such as acetone and 2-butanone, halogenated hydrocarbons such as methylene chloride and chloroform, and cyclic ethers such as tetrahydrofuran are preferably used. It is done. Regarding the treatment of the organic solvent, the titanyl phthalocyanine crystal may be simply immersed in the organic solvent as it is, but the treatment time can be shortened by using auxiliary means such as stirring and ultrasonic application together. ,It is valid. The target titanyl phthalocyanine crystal can be obtained by performing a treatment with an organic solvent, filtering and separating, and drying again.

  As another method, a crystal transformation is performed by applying mechanical shearing force to the previously prepared titanyl phthalocyanine crystal. At this time, an organic solvent may be used in combination, but it is desirable to perform the treatment in a dry state without using it together. As a method to be used, dry milling using a ball mill, attritor, vibration mill, kneader, or the like, or simply dry milling using a mixer is also effective. Moreover, you may use inorganic salts, such as salt, as an adjuvant in the case of dry milling. When an auxiliary agent is used, a washing step for removing inorganic salts is necessary after the crystal conversion treatment. Thus, the target titanyl phthalocyanine crystal can be obtained.

  Whichever method is used, it is important that the peak intensity at 26.3 ° is in the range of 0.1 to 5% with respect to the peak intensity at the maximum diffraction peak of 27.2 °. The peak intensity of 26.3 ° is determined by the treatment time in the solvent or the treatment time giving mechanical shearing force, but the state of the raw material used (the titanyl phthalocyanine crystal produced by the first crystal conversion) (for example, It is desirable to determine the treatment time through preliminary experiments because it varies depending on the size and hardness of the powder.

  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).

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 and the dispersibility of the pigment.
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. That is, 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 fine particle formation 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.

Next, a method for removing coarse particles after dispersing titanyl phthalocyanine crystals 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 and the dispersibility of the pigment.

  That is, after preparing a dispersion liquid in which the particles are made as fine as possible without causing crystal transition, it is a method of filtering with a suitable 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, preferably 0.2 μm or less) can be prepared, and a photoconductor using this can be used in an image forming apparatus. By doing so, the effect of the present application is further enhanced.

  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 exceeding 3 μm at least 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. 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.

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, (1) 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. (2) 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. (3) As a result, the manufactured photoreceptor is stably manufactured with high resistance to soiling.

The intensity ratio of the 26.3 ° peak intensity to the 27.2 ° peak intensity in the titanyl phthalocyanine crystal of the present invention will be described.
An X-ray diffraction spectrum is measured with a general X-ray diffractometer in a powder state of the titanyl phthalocyanine crystal to be used. Baseline correction is performed on the obtained spectrum, and then a peak intensity of 26.3 ± 0.2 ° and a peak intensity of 27.2 ± 0.2 ° are obtained. Using the value, the value obtained by dividing the peak intensity of 26.3 ± 0.2 ° by the peak intensity of 27.2 ± 0.2 ° is the peak intensity ratio in the present invention.
Peak intensity ratio (%) =
(26.3 ± 0.2 ° peak intensity / 27.2 ± 0.2 ° peak intensity) × 100
When the peak intensity ratio is 1% or less, it may be difficult to correct the baseline in measurement over a wide range. In that case, the intensity ratio can be obtained more accurately by narrowing the measurement range (for example, measuring within a range of 25 to 30 °) and performing remeasurement.

Next, the electrophotographic photosensitive member used in the present invention will be described in detail with reference to the drawings.
FIG. 9 is a cross-sectional view showing a structural example of the electrophotographic photosensitive member used in the present invention. On the conductive support 1, the conductive layer 5, the charge blocking layer 6, and a specific average particle having a specific crystal type are shown. A photosensitive layer 4 containing a titanyl phthalocyanine crystal having a size smaller than that is sequentially laminated.
FIG. 10 is a cross-sectional view showing another structural example of the electrophotographic photosensitive member used in the present invention. The conductive layer 1, the charge blocking layer 6, and a specific crystal type are specified on the conductive support 1. A charge generation layer 7 containing a titanyl phthalocyanine crystal having an average particle size or less and a charge transport layer 8 mainly composed of a charge transport material are sequentially laminated.
FIG. 11 is a cross-sectional view showing still another structural example of the electrophotographic photosensitive member used in the present invention, and has a conductive layer 5, a charge blocking layer 6, and a specific crystal type on the conductive support 1. The charge generation layer 7 containing a titanyl phthalocyanine crystal having a specific average particle size or less, the charge transport layer 8 mainly composed of a charge transport material, and the protective layer 9 are sequentially stacked.

Examples of the conductive support include those having a volume resistance of 10 ¹⁰ Ω · cm or less, such as metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, and platinum, tin oxide, and indium oxide. Metal oxide coated with film or cylindrical plastic or paper by vapor deposition or sputtering, or a plate made of aluminum, aluminum alloy, nickel, stainless steel, etc. After the conversion, a tube subjected to surface treatment such as cutting, superfinishing or polishing can be used. Further, endless nickel belts and endless stainless steel belts disclosed in JP-A-52-36016 can also be used as the conductive support.

  In addition, the conductive support dispersed in a suitable binder resin on the support can be used as the conductive support of the present invention. Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc and silver, or metal oxide powder such as conductive tin oxide and ITO. 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, it is electrically conductive by a heat shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon (registered trademark) on a suitable cylindrical substrate. Those provided with a conductive layer can also be used favorably as the conductive support of the present invention.

Next, the conductive layer will be described.
The conductive layer is formed as a conductive film on the conductive support in order to improve the coatability of the photosensitive layer, protect the photosensitive layer from electrical breakdown, and cover defects on the substrate surface. This conductive layer is not only required to have a sufficiently low resistance, but also must prevent charge accumulation and provide stable potential characteristics when used repeatedly in high-speed electrophotographic processes. I must.
The conductive film is formed by providing a conductive material by a dry film forming method such as vapor deposition or sputtering, or by dispersing conductive powder in a binder resin. As the conductive powder, a material having a specific resistance of 10 ⁶ Ω · cm or less is effectively used. Metal powder such as nickel, copper, silver, and aluminum, iron oxide, tin oxide, antimony oxide, indium oxide, etc. Conductive metal oxide powder (conductive inorganic pigment), carbon black, fibrous carbon, and the like such as a mixture of the above are used. A vapor deposition film containing indium oxide doped with tin, tin oxide or a mixture of both can also be used. In any case, it is preferable that the volume resistance value in the electric field strength (approximately 105 V / cm) of the photosensitive member in the state of the conductive layer is in the range of 10 ⁵ Ω · cm to 10 ¹⁰ Ω · cm. is there.

  The conductive layer of the present invention also has a function of preventing the generation of moire images due to light interference inside the photosensitive layer when writing with coherent light such as laser light. The effect becomes even more remarkable. In order to exhibit such a function, it is effective that the conductive layer has a material having a large refractive index. In addition to the conductive metal oxides and conductive inorganic pigments described above, fine spheres or roughening agents mainly composed of polydimethylsiloxane may be introduced.

As the binder resin, the same resin as the charge blocking layer described later can be used. However, considering that the charge blocking layer and the photosensitive layer are laminated on the conductive layer, the binder resin is not affected by the coating solvent for the charge blocking layer or the photosensitive layer. It is important.
A thermosetting resin is preferably used as the binder resin. In particular, alkyd / melamine resin mixtures are best used. At this time, the mixing ratio of alkyd / melamine resin is an important factor that determines the structure and characteristics of the conductive layer. A range in which the ratio (weight ratio) between the two is 5/5 to 8/2 can be cited as a good mixing ratio range. If the melamine resin is richer than 5/5, volume shrinkage is increased during thermosetting, and coating film defects are likely to occur, or the residual potential of the photoreceptor is increased. Further, if the alkyd resin is richer than 8/2, it is effective in reducing the residual potential of the photoreceptor, but it is not desirable because the bulk resistance becomes too low and the soiling becomes worse.
The thickness of the conductive layer is 1 to 20 μm, preferably 2 to 10 μm. If the film thickness is less than 1 μm, the effect is small, and if it exceeds 20 μm, residual potential may be accumulated or the coating surface properties may be deteriorated.

  The conductive inorganic pigment and conductive metal oxide described above are dispersed together with a solvent and a binder resin by a conventional method, for example, a ball mill, a sand mill, an attrier, etc., and a chemical necessary for curing (crosslinking) as necessary, A solvent, an additive, a curing accelerator, and the like are added, and the film is formed on the substrate by a conventional method such as blade coating, dip coating, spray coating, beat coating, or nozzle coating. After the coating, it is dried or cured by a curing process such as drying, heating, or light.

Next, the charge blocking layer will be described.
The charge blocking layer is a layer having a function of preventing reverse polarity charges induced on the electrode (conductive support) during charging of the photoreceptor from being injected from the support into the photosensitive layer via the conductive layer. . In the case of negative charging, it has a function of preventing hole injection, and in the case of positive charging, it has a function of preventing electron injection. As the charge blocking layer, an anodized film typified by an aluminum oxide layer, an inorganic insulating layer typified by SiO (silicon oxide), and a metal oxide glass as described in JP-A-3-191361 A layer formed of a quality network, a layer of polyphosphazene as described in JP-A-3-141363, a layer of an aminosilane reaction product as described in JP-A-3-101737, Other examples include a layer made of an insulating binder resin and a layer made of a curable binder resin. In particular, a layer composed of an insulating binder resin or a curable binder resin that can be formed by a wet coating method can be used favorably. Since the charge blocking layer is formed by laminating a photosensitive layer thereon, when the photosensitive layer is provided by a wet coating method, it is important that the coating layer is made of a material or a composition that does not attack the coating film by these coating solvents. is there.

Examples of the binder resin that can be used include thermoplastic resins such as polyvinyl alcohol, vinyl acetate resin, polyamide, polyester, and vinyl chloride-vinyl acetate copolymer, and thermosetting resins such as active hydrogen (-OH group, -NH ₂ A thermosetting resin obtained by thermally polymerizing a compound containing a plurality of hydrogen atoms such as a group and a —NH group, a compound containing a plurality of isocyanate groups and / or a compound containing a plurality of epoxy groups. In this case, examples of the compound containing a plurality of active hydrogens include acrylic resins containing active hydrogen such as polyvinyl butyral, phenoxy resin, phenol resin, polyamide, polyester, polyethylene glycol, polypropylene glycol, polybutylene glycol, and hydroxyethyl methacrylate groups. Based resins and the like. Examples of the compound containing a plurality of isocyanate groups include tolylene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, and prepolymers thereof. Examples of the compound having a plurality of epoxy groups include bisphenol A type epoxy resin. can give. Among these, polyamide is most preferably used from the viewpoints of film formability, environmental stability, and solvent resistance.

Further, a thermosetting resin obtained by thermally polymerizing an oil-free alkyd resin and an amino resin such as a butylated melamine resin, a polyurethane having an unsaturated bond, a resin having an unsaturated bond such as an unsaturated polyester, and thioxanthone A photocurable resin such as a combination with a photopolymerization initiator such as a compound based on methylbenzyl formate can also be used as the binder resin.
Further, a conductive polymer having a rectifying property, an acceptor (donor) resin / compound or the like may be added in accordance with the charging polarity, and a function of suppressing charge injection from the substrate may be provided.

  The film thickness of the charge blocking layer is 0.1 μm or more and less than 2.0 μm, preferably about 0.3 μm or more and 1.0 μm or less. When the charge blocking layer becomes thick, the residual potential increases remarkably at low temperatures and low humidity due to repeated charging and exposure, and when the film thickness is too thin, the blocking effect is reduced. Add chemicals, solvents, additives, curing accelerators, etc. necessary for curing (crosslinking), and apply to the substrate by conventional methods such as blade coating, dip coating, spray coating, beat coating, nozzle coating, etc. It is formed. After the application, it is dried or cured by a curing process such as drying, heating, light or electron beam.

Next, the photosensitive layer will be described. The photosensitive layer may be a single-layered photosensitive layer containing a charge generation material and a charge transport material, but as described above, the laminated type composed of the charge generation layer and the charge transport layer has excellent characteristics in sensitivity and durability. Shown and used well.
The charge generation layer 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), Furthermore, it has major peaks at 9.4 °, 9.6 °, and 24.0 °, and has a peak at 7.3 ° as the lowest diffraction peak, a peak at 7.3 °, and 9. A titanyl phthalocyanine having a peak between 4 ° and a peak at 26.3 °, having an average particle size of 0.25 μm or less at the time of crystal synthesis or by dispersion filtration, and having no coarse particles It is a layer mainly composed of crystals.

For the charge generation layer, the pigment is dispersed in a suitable solvent together with a binder resin as necessary using a ball mill, attritor, sand mill, ultrasonic wave, etc., and this is applied onto a conductive support and dried. It is formed by.
As the binder resin used for the charge generation layer as necessary, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly-N- Vinyl carbazole, 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, etc. It is done. 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 thickness of the charge generation layer is suitably about 0.01 to 5 μm, preferably 0.1 to 2 μm.

The charge transport layer can be formed by dissolving or dispersing the charge transport material and the binder resin in an appropriate 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 charge transport material include chloranil, 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 appropriately 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. The thickness of the charge transport layer is preferably about 5 to 100 μm.
Examples of the solvent used here include tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, and acetone. Among these, 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.

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 and q are each independently an integer of 0 to 4, k and j are compositions, 0.1 ≦ k ≦ 1, 0 ≦ j ≦ 0.9, and 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—, —SO ₂ —. , -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. )

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 those in the formula (I). In the formula (II), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

In 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 those in the formula (I). In the formula (III), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

_{Wherein, R 11,} R ₁₂ is a substituted or unsubstituted aryl _{group, Ar 7, Ar 8, Ar} 9 are identical or different arylene group, p is an integer of 1-5. X, k, j and n are the same as those in the formula (I). In the formula (IV), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

In the formula, 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 substituted or unsubstituted Represents a substituted vinylene group. X, k, j and n are the same as those in the formula (I). In the formula (V), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

In the formula, R ₁₅ , R ₁₆ , R ₁₇ , R ₁₈ are substituted or unsubstituted aryl groups, Ar ₁₃ , Ar ₁₄ , Ar ₁₅ , Ar ₁₆ are the same or different arylene groups, Y ₁ , Y ₂ , Y ₃ are 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 may be the same or different. X, k, j and n are the same as those in the formula (I). In the formula (VI), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

In 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 those in the formula (I). In the formula (VII), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

In 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 those in the formula (I). In the formula (VIII), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

In the formula, 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 those in the formula (I). In the formula (IX), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

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

  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.

Further, a charge transport layer having a crosslinked structure is also effectively used as the structure of the charge transport 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 transport site is formed in the network structure, and the function as the charge transport 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 charge transport layer is a laminated structure, the charge transport layer of the low molecular weight dispersion polymer is used on the lower charge generation layer side, and the charge transport layer having a crosslinked structure is formed on the upper layer (surface side). You may do it.

  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 copolymers of known monomers, block polymers, graft polymers, star polymers, and, for example, JP-A-3-109406, JP-A-2000- It is also possible to use a cross-linked polymer having an electron donating group as disclosed in JP-A-206723 and JP-A No. 2001-34001.

  In the present invention, a plasticizer or a leveling agent may be added to the charge transport layer. As the plasticizer, those used as general plasticizers 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, 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 above description, the photosensitive layer has a laminated structure. However, in the present invention, the photosensitive layer may have a single layer structure. In order to make the photosensitive layer as a single layer, the photosensitive layer is constituted by providing a single layer containing at least the above-described charge generating substance and a binder resin. As the binder resin, the description of the charge generating layer and the charge transport layer is used. Those described in the above are used well. In addition, when a charge transport material is used in combination with the single-layer photosensitive layer, high photosensitivity, high carrier transport properties, and low residual potential are exhibited, and the single layer photosensitive layer can be used favorably. At this time, as the charge transport material to be used, either a hole transport material or an electron transport material is selected according to the polarity charged on the surface of the photoreceptor. Furthermore, since the above-described polymer charge transporting material also has the functions of a binder resin and a charge transporting material, it is favorably used for a single-layer photosensitive layer.

  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 is 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 effectively use the photosensitive member of the present invention having no abnormal defect.

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

Furthermore, a protective layer having a crosslinked structure is also effectively used as the 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 transport site is formed in the network structure, and the charge transport function can be sufficiently expressed. A reactive monomer having a triarylamine structure is effectively used as the monomer having charge transporting ability.

Other protective layers include fluorine resins such as polytetrafluoroethylene, silicone resins, and inorganic fillers such as titanium oxide, tin oxide, potassium titanate, and silica for the purpose of improving wear resistance. What disperse | distributed the filler etc. can be added.
Among the filler materials used for the protective layer of the photoreceptor, examples of the organic filler material include fluorine resin 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 Examples thereof include inorganic materials such as oxides and potassium titanate. 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.
Moreover, the volume average particle diameter of the filler to be 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.

The average particle diameter of the filler in the present invention is a volume average particle diameter unless otherwise specified, and is determined by an ultracentrifugal automatic particle size distribution analyzer: CAPA-700 (manufactured by Horiba). 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 of 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 the 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, so that dispersibility and stability thereof are improved.
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.

Further, as the filler that is less likely to cause image blur, 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 fillers having a dielectric constant of 5 or more. Among these fillers, α-type alumina, which has a high insulation property, high thermal stability, and high wear resistance, is a hexagonal close-packed structure, which suppresses image blur and improves wear resistance. Is particularly useful from

The specific resistance of the filler used in the present invention is defined as follows. Since the specific resistance value of the powder such as the filler varies depending on the filling rate, it is necessary to measure under a certain condition. In the present invention, the specific resistance of the filler is measured using an apparatus having the same configuration as the measuring apparatus shown in Japanese Patent Laid-Open Nos. 5-94049 (FIG. 1) and 5-113688 (FIG. 1). The value was measured and 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 RESISTANCE METER (Yokogawa Hewlett Packard), and the area below it was measured with a digital multimeter (Fluk). The specific resistance value obtained in this way is defined as the specific resistance value according to 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. The capacitance was measured by using a dielectric loss measuring device (Ando Electric).
Furthermore, these fillers can be surface-treated with at least one surface treatment agent, and it is preferable from the viewpoint of filler dispersibility. Lowering the dispersibility of the filler not only increases the residual potential, but also lowers the transparency of the coating, causes defects in the coating, and lowers 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, titanate coupling agents, aluminum coupling agents, zircoaluminate coupling agents, higher fatty acids, etc., or mixed treatments of these with silane coupling agents, Al ₂ O ₃ , TiO ₂ , ZrO ₂ , Silicone, aluminum stearate, or the like, or a mixture thereof is more preferable from the viewpoint 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 dispersing effect cannot be obtained, and if the surface treatment amount 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 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 referred to here represents 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. In addition, about 0.1-10 micrometers is suitable for the thickness of a protective layer. 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.

Next, the image forming apparatus of the present invention will be described in detail with reference to the drawings.
FIG. 12 is a schematic diagram for explaining the image forming process and the image forming apparatus of the present invention, and the following modifications also belong to the category of the present invention.
In FIG. 12, the photoconductor 11 is provided with at least a conductive layer, a charge blocking layer, and a photosensitive layer on a conductive support, and the photosensitive layer has a diffraction peak with a Bragg angle 2θ with respect to CuKα rays (wavelength 1.542 mm) ( ± 0.2 °) and has a maximum diffraction peak at least 27.2 °, and further has major peaks at 9.4 °, 9.6 °, and 24.0 °, and the diffraction at the lowest angle. The average particle of the primary particles having a peak at 7.3 °, no peak between the peak at 7.3 ° and the peak at 9.4 °, and a peak at 26.3 ° It contains a titanyl phthalocyanine crystal having a size of 0.25 μm or less. The photoconductor 11 has a drum shape, but may have a sheet shape or an endless belt shape. The charging roller 13, the pre-transfer charger 17, the transfer charger 20, the separation charger 21, and the pre-cleaning charger 23 include a corotron, scorotron, a solid state charger, a charging roller, and a transfer roller. Means are used.

Of these charging methods, a contact charging method or a non-contact proximity arrangement method is particularly desirable. The contact charging method has advantages such as high charging efficiency, a small amount of ozone generation, and downsizing of the apparatus.
The contact-type charging member referred to here is a type in which the surface of the charging member is in contact with the surface of the photosensitive member, and includes a charging roller, a charging blade, and a charging brush. Of these, charging rollers and charging brushes are used favorably.

Further, the charging member arranged in the proximity is a type in which the charging member is arranged in a non-contact state so as to have a gap (gap) of 200 μm or less (preferably 100 μm or less) between the surface of the photosensitive member and the surface of the charging member. It is distinguished from known chargers typified by corotron and scorotron from the distance of the gap. The adjacently arranged charging member used in the present invention may have any shape as long as it has a mechanism capable of appropriately controlling the gap with the surface of the photoreceptor. For example, the rotation shaft of the photosensitive member and the rotation shaft of the charging member may be mechanically fixed so as to have an appropriate gap. Among them, using a charging member in the shape of a charging roller, a gap forming member is disposed at both ends of the non-image forming portion of the charging member, and only this portion is brought into contact with the surface of the photoreceptor, and the image forming region is disposed in a non-contact manner. Alternatively, the gap forming member at both ends of the non-photosensitive portion of the photoconductor is disposed, and only this portion is brought into contact with the surface of the charging member, and the image forming region is disposed in a non-contact manner, so that the gap can be stably stabilized. It is a method that can be maintained. In particular, the methods described in JP-A Nos. 2002-148904 and 2002-148905 can be used satisfactorily. An example of the proximity charging mechanism in which the gap forming member is arranged on the charging member side is shown in FIG. In FIG. 13, 11 is a photoconductor, 33 is an image forming area thereof, 34 is a non-image forming area, 13 is a charging roller, 31 is a gap forming member, and 32 is a cored bar.
By using the above-mentioned method, there are advantages such as high charging efficiency and low ozone generation, miniaturization of the apparatus, no contamination with toner, etc., and no mechanical wear due to contact. Because it is used well. Furthermore, as an application method, there is an advantage that uneven charging is less likely to occur by using AC superposition, and it can be used satisfactorily.

  When such a contact type charging member or a non-contact charging type charging member is used, there is a drawback that dielectric breakdown of the photosensitive member is likely to occur. However, the photoconductor used in the present invention has an intermediate layer composed of a laminated structure of a conductive layer and a charge blocking layer, and further, the photoconductive layer does not contain coarse particles of a charge generating material. Extremely high pressure resistance. For this reason, the resistance against the dielectric breakdown of the photosensitive member is high, and the merit (prevention of uneven charging) of the charging member can be utilized.

  Although the photosensitive member is charged by such a charging member, in a normal image forming apparatus, since background contamination due to the photosensitive member is likely to occur, the electric field strength applied to the photosensitive member is set to be low ( 40V / μm or less, preferably 30V / μm or less). This is because the occurrence of soiling depends on the electric field strength, and the probability of soiling increases as the electric field strength increases. However, reducing the electric field strength applied to the photoreceptor reduces the efficiency of photocarrier generation and reduces the photosensitivity. In addition, since the electric field strength applied between the surface of the photosensitive member and the conductive support is reduced, the straightness of the photocarrier generated in the photosensitive layer is reduced, and diffusion due to clone repulsion is increased, resulting in a reduction in resolution. Arise. On the other hand, by using the electrophotographic photosensitive member of the present invention, the probability of occurrence of soiling can be extremely reduced, so there is no need to reduce the electric field intensity more than necessary, and it can be used even under an electric field intensity of 40 V / μm or more. become able to. For this reason, a sufficient amount of gain in the attenuation of the photoreceptor light can be secured, a large margin can be created for development (potential) described later, and development can be performed without reducing the resolution.

The image exposure unit 15 uses a light source capable of ensuring high luminance such as a light emitting diode (LED), a semiconductor laser (LD), and electroluminescence (EL).
As a light source such as the static elimination lamp 12, general light emitting materials such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL) can be used. . Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.

Among these light sources, light emitting diodes and semiconductor lasers have high irradiation energy and long wavelength light of 600 to 800 nm, so that the above-mentioned phthalocyanine pigment, which is a charge generation material, exhibits high sensitivity and is used well. The
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.

  The toner developed on the photoconductor 11 by the developing unit 16 is transferred to the transfer paper 19, but not all is transferred, and some toner remains on the photoconductor 11. Such toner is removed from the photoreceptor by the fur brush 24 and the blade 25. 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.

When a positive (negative) charge is applied to the electrophotographic photosensitive member and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member.
If this is developed with toner of negative (positive) polarity (detection fine particles), a positive image can be obtained, and if developed with toner of positive (negative) polarity, a negative image can be obtained.
A known method is applied to the developing unit, and a known method is also used for the charge eliminating unit.

  FIG. 14 shows another example of the electrophotographic process according to the present invention. The photoreceptor 41 is an endless belt-shaped photoreceptor, and is provided with at least a conductive layer, a charge blocking layer, and a photosensitive layer on a conductive support, and the photosensitive layer has a Bragg angle 2θ with respect to CuKα rays (wavelength 1.542 mm). Diffraction peak (± 0.2 °) has a maximum diffraction peak at least 27.2 °, and further has major peaks at 9.4 °, 9.6 °, and 24.0 °, the lowest The angle side diffraction peak has a peak at 7.3 °, has no peak between the 7.3 ° peak and the 9.4 ° peak, and has a peak at 26.3 °. It contains titanyl phthalocyanine crystals having an average particle size of 0.25 μm or less. Driven by the driving rollers 42a and 42b, charging by the charging charger 43, image exposure by the light source 44, development (not shown), transfer using the transfer charger 45, exposure before cleaning by the image exposure source 46, cleaning by the brush 47, light source The charge removal by 48 is repeated. In FIG. 14, pre-cleaning exposure is performed on the photoconductor 41 (of course, the support is translucent) from the support side.

The above illustrated electrophotographic process is illustrative of an embodiment of the present invention, and of course other embodiments are possible. For example, in FIG. 14, image exposure is performed from the photosensitive layer side, but this may be performed from the translucent support side, or irradiation of static elimination light may be performed from the support side.
On the other hand, the light irradiation process is illustrated as image exposure, pre-cleaning exposure, and static elimination exposure. In addition, a pre-transfer exposure, a pre-exposure of image exposure, and other known light irradiation processes are provided to light the photosensitive member. Irradiation can also be performed.

  The image forming means as described above may be fixedly incorporated in a copying apparatus, a facsimile, or a printer, but may be incorporated in these apparatuses in the form of a process cartridge. A process cartridge is a single device (part) that contains a photoconductor and further includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, a neutralizing unit, and the like. There are many shapes and the like of the process cartridge, but a general example is shown in FIG. In FIG. 15, 51 is a photoconductor, 55 is a cleaning brush, 53 is a charging roller, 57 is a transfer roller, and 56 is a developing roller. The photoreceptor 51 is provided with at least a conductive layer, a charge blocking layer, and a photosensitive layer on a conductive support, and the photosensitive layer has a diffraction peak (± 0.2) with a Bragg angle 2θ with respect to CuKα rays (wavelength 1.542Å). )) Has a maximum diffraction peak at least 27.2 °, and further has main peaks at 9.4 °, 9.6 °, and 24.0 °, and the diffraction peak at the lowest angle is 7. It has a peak at 3 °, no peak between the peak at 7.3 ° and the peak at 9.4 °, and has a peak at 26.3 °, and the average particle size of the primary particles is 0.00. It contains a titanyl phthalocyanine crystal that is 25 μm or less.

FIG. 16 is a schematic diagram for explaining the tandem-type full-color electrophotographic apparatus of the present invention, and the following modifications also belong to the category of the present invention.
In FIG. 16, reference numerals 61C, 61M, 61Y, and 61K denote drum-shaped photoconductors. The photoconductor 61 is formed by providing at least a conductive layer, a charge blocking layer, and a photosensitive layer on a conductive support. Has 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). Further, 9.4 °, 9.6 °, 24 It has a major peak at 0.0 °, the lowest diffraction peak at 7.3 °, and no peak between 7.3 ° and 9.4 ° And a titanyl phthalocyanine crystal having a peak at 26.3 ° and an average primary particle size of 0.25 μm or less.

  The photoreceptors 61C, 61M, 61Y, 61K rotate in the direction of the arrow in the figure, and around them, at least in the order of rotation, charging members 62C, 62M, 62Y, 62K, developing members 64C, 64M, 64Y, 64K, cleaning members 65C, 65M, 65Y, and 65K are arranged. The charging members 62C, 62M, 62Y, and 62K are charging members that constitute a charging device for uniformly charging the surface of the photoreceptor. Laser light 63C, 63M, 63Y, and 63K from an exposure member (not shown) is irradiated from the photosensitive member side between the charging members 62C, 62M, 62Y, and 62K and the developing members 64C, 64M, 64Y, and 64K. Electrostatic latent images are formed on 61M, 61Y, and 61K. Then, four image forming elements 66C, 66M, 66Y, and 66K centering around the photoreceptors 61C, 61M, 61Y, and 61K are juxtaposed along the transfer conveyance belt 70 that is a transfer material conveyance unit. The transfer conveyance belt 70 contacts the photosensitive members 61C, 61M, 61Y, and 61K between the developing members 64C, 64M, 64Y, and 64K of the image forming units 66C, 66M, 66Y, and 66K and the cleaning members 65C, 65M, 65Y, and 65K. Transfer brushes 71 </ b> C, 71 </ b> M, 71 </ b> Y, and 71 </ b> K for applying a transfer bias are disposed on the surface (back surface) that is in contact with and contacts the back side of the photoconductor side of the transfer conveyance belt 10. Each of the image forming elements 66C, 66M, 66Y, and 66K is different in toner color inside the developing device, and the other components are the same in configuration.

  In the color electrophotographic apparatus having the configuration shown in FIG. 16, the image forming operation is performed as follows. First, in each of the image forming elements 66C, 66M, 66Y, and 66K, the photoconductors 61C, 61M, 61Y, and 61K are charged by charging members 62C, 62M, 62Y, and 62K that rotate in the direction of the arrow (the direction along with the photoconductor). Next, an electrostatic latent image corresponding to each color image to be created is formed by laser light 63C, 63M, 63Y, and 63K by an exposure unit (not shown) disposed inside the photoconductor. Next, the latent image is developed by developing members 64C, 64M, 64Y, and 64K to form a toner image. Development members 64C, 64M, 64Y, and 64K are development members that perform development with toners of C (cyan), M (magenta), Y (yellow), and K (black), respectively, and the four photosensitive members 61C, 61M, and 61Y. , 61K, each color toner image is superimposed on the transfer paper. The transfer paper 67 is sent out from the tray by a paper feed roller 68, temporarily stopped by a pair of registration rollers 69, and sent to the transfer conveyance belt 70 in synchronism with the image formation on the photosensitive member. The transfer paper 67 held on the transfer conveyance belt 70 is conveyed, and each color toner image is transferred at a contact position (transfer portion) with each of the photoreceptors 61C, 61M, 61Y, 61K. The toner image on the photoconductor is transferred onto the transfer paper 67 by an electric field formed by a potential difference between the transfer bias applied to the transfer brushes 61C, 61M, 61Y, and 61K and the photoconductors 61C, 61M, 61Y, and 61K. The Then, the recording paper 7 on which the four color toner images are passed through the four transfer portions is conveyed to the fixing device 12, where the toner is fixed, and is discharged to a paper discharge portion (not shown). Further, the residual toner remaining on the photosensitive members 61C, 61M, 61Y, and 61K without being transferred by the transfer unit is collected by the cleaning devices 65C, 65M, 65Y, and 65K. In the example of FIG. 16, the image forming elements are arranged in the order of C (cyan), M (magenta), Y (yellow), and K (black) from the upstream side to the downstream side in the transfer paper 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 the image forming elements (66C, 66M, 66Y) other than black. Further, in FIG. 16, the charging member is in contact with the photosensitive member, but by using a charging mechanism as shown in FIG. 13, an appropriate gap (about 10 to 200 μm, preferably 100 μm or less) is provided between them. By providing it, the wear amount of the both can be reduced, and toner filming to the charging member can be reduced and it can be used satisfactorily.

  The image forming means as described above may be fixedly incorporated in a copying apparatus, facsimile, or printer, but each electrophotographic element may be incorporated in the apparatus in the form of a process cartridge. A process cartridge is a single device (part) that contains a photoconductor and further includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, a neutralizing unit, and the like.

As described above, as is clear from the detailed and specific description, according to the present invention, an electrophotographic photosensitive member that does not generate an abnormal image and outputs a stable image when used repeatedly at high speed is provided. Specifically, reduction of background contamination due to repeated use, prevention of residual potential, reduction of dielectric breakdown during charging by a contact charging member or a nearby charging member, and stable electrophotographic characteristics in all environments There is provided a highly durable electrophotographic photosensitive member that makes it possible.
In addition, an image forming apparatus is provided that generates less abnormal images even when repeated image formation (output) is performed using the photoconductor. Specifically, there is provided an image forming apparatus capable of stable operation with high durability, which solves the greatest problems when using negative / positive development such as background contamination, density reduction, and density unevenness in a halftone image. In addition, an image forming apparatus that is less dependent on the environment and capable of stable operation in any environment is provided.
Furthermore, there is provided a process cartridge for an image forming apparatus that uses the photoconductor and is highly durable and easy to handle.

Hereinafter, although an example is given and the present invention is explained, the present invention is not restricted by an example. All parts are parts by weight.
First, a synthesis example of the charge generation material used in the present invention will be described.
(Comparative Synthesis Example 1)
A pigment was prepared according to Japanese Patent Application Laid-Open No. 2001-187794. 292 g of 1,3-diiminoisoindoline and 2000 ml of sulfolane are mixed, and 204 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 the 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. Dissolve the crude titanyl phthalocyanine in 20 times the amount of concentrated sulfuric acid, add dropwise to 100 times the amount of ice water with stirring, filter the precipitated crystals, and then repeat washing with water until the washing solution becomes neutral (ion-exchanged water after washing). PH value was 6.8), and a titanyl phthalocyanine pigment wet cake (water paste) was obtained. 400 g of the obtained wet cake (water paste) was put into 2000 g of tetrahydrofuran, stirred for 4 hours, filtered and dried to obtain titanyl phthalocyanine powder. Further, 30 g of this titanyl phthalocyanine crystal was immersed in 300 g of tetrahydrofuran, and the second crystal conversion was performed. After leaving it immersed for 12 hours, it was separated by filtration and dried under reduced pressure under the same conditions as above to obtain a titanyl phthalocyanine crystal used in the present invention. This is designated 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. In addition, the raw material of the comparative synthesis example 1 does not use a halide.

(Synthesis Example 1)
According to the method of Comparative Synthesis Example 1, an aqueous paste of titanyl phthalocyanine pigment was synthesized, and crystal conversion was performed as follows to obtain phthalocyanine crystals having smaller primary particles than Comparative Synthesis Example 1.
To 600 parts of the water paste before crystal conversion obtained in Comparative Synthesis Example 1, 4000 parts of tetrahydrofuran was added and stirred vigorously (2000 rpm) with a homomixer (Kennis, MARKIIf model) at room temperature. The dark blue color of the paste was 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 filter were washed with tetrahydrofuran to obtain a pigment wet cake. This was dried under reduced pressure (5 mmHg) at 70 ° C. for 2 days to obtain 88 parts of titanyl phthalocyanine crystals.
Further, 30 g of this titanyl phthalocyanine crystal was immersed in 300 g of tetrahydrofuran, and the second crystal conversion was performed. After leaving it immersed for 12 hours, it was separated by filtration and dried under reduced pressure under the same conditions as above to obtain a titanyl phthalocyanine crystal used in the present invention. This is designated as Pigment 2. 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.

(Synthesis Example 2)
The treatment was performed in the same manner as in Synthesis Example 1 except that the second crystal conversion operation in Synthesis Example 1 was changed to the following conditions to obtain a titanyl phthalocyanine crystal of the present invention (see FIG. 18). This is designated as Pigment 3.
(Second crystal conversion process)
30 g of titanyl phthalocyanine crystals subjected to the first crystal conversion treatment were subjected to mechanical shearing force for 5 minutes by a commercially available mixer, and then the powder was taken out.

(Synthesis Example 3)
The treatment was performed in the same manner as in Synthesis Example 1 except that the second crystal conversion operation in Synthesis Example 1 was changed to the following conditions to obtain a titanyl phthalocyanine crystal of the present invention. This is designated as Pigment 4.
(Second crystal conversion process)
30 g of titanyl phthalocyanine crystals subjected to the first crystal conversion treatment were put into a φ90 mm glass pot together with 2 kg of φ6 mm zirconia balls, and after dry milling for 10 minutes, the powder was taken out.

(Comparative Synthesis Example 2)
A titanyl phthalocyanine crystal was obtained in the same manner as in Comparative Synthesis Example 1 except that the second crystal conversion solvent in Comparative Synthesis Example 1 was changed from tetrahydrofuran to methanol. This is designated as Pigment 5.
(Comparative Synthesis Example 3)
In Comparative Synthesis Example 1, treatment was performed in the same manner as in Comparative Synthesis Example 1 except that 2-butanone was used in place of tetrahydrofuran as the first crystal conversion solvent and the second crystal conversion was not performed, and the titanyl phthalocyanine crystal was Obtained. This is designated as Pigment 6.

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.
X-ray diffraction spectra of the dry powder of the water paste obtained as described above and the titanyl phthalocyanine crystals obtained in Synthesis Examples 1 to 3 and Comparative Synthesis Examples 1 to 3 were measured under the following conditions. An X-ray diffraction spectrum of the dry powder of the water paste is shown in FIG.
X-ray tube: Cu
Voltage: 40 kV
Current: 20 mA
Scanning speed: 1 ° / min Scanning range: 3 ° -40 °
Time constant: 2 seconds

As for Comparative Synthesis Example 1 and Synthesis Examples 1 to 3, since the same X-ray diffraction spectrum was shown in each case except for the peak intensity of 26.3 °, the titanyl phthalocyanine obtained in Synthesis Example 2 as a representative example The X-ray diffraction spectrum of the crystal is shown in FIG. 18 (the arrow in the figure is a peak at 26.3 °, and the peak intensity ratio is 8%).
The X-ray diffraction spectrum of the titanyl phthalocyanine crystal obtained in Comparative Synthesis Example 2 is shown in FIG. 19, but it did not show a peak at 26.3 °.
An X-ray diffraction spectrum of the titanyl phthalocyanine crystal obtained in Comparative Synthesis Example 3 is shown in FIG. 20, and the lowest angle exists at 7.5 °.

(Comparative Synthesis Example 4)
A pigment was prepared according to the method described in JP-A-1-299874 (Patent No. 2512081) and Example 1. That is, the wet cake produced in the previous 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 mixture was washed successively with dilute sulfuric acid and aqueous ammonium hydroxide and dried to obtain a pigment. This is designated as Pigment 7.

(Comparative Synthesis Example 5)
A pigment was produced according to the method described in JP-A-3-269064 (Japanese Patent No. 2854682) and Production Example 1. That is, the wet cake prepared in Synthesis Example 1 was dried, and 1 g of the dried product was stirred for 1 hour (50 ° C.) in a mixed solvent of 10 g of ion-exchanged water and 1 g of monochlorobenzene, and then washed with methanol and ion-exchanged water. And dried to obtain a pigment. This is designated as Pigment 8.

(Comparative Synthesis Example 6)
A pigment was produced according to the method described in the production example of JP-A-2-8256 (Japanese Patent Publication No. 7-91486). 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 then several times with 80 hot water. After washing, it was dried to obtain a pigment. This is designated as Pigment 9.

(Comparative Synthesis Example 7)
A pigment was prepared according to the method described in JP-A No. 64-17066 (Japanese Patent Publication No. 7-97221) 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 dried to obtain a pigment. This is designated as Pigment 10.

(Comparative Synthesis Example 8)
A pigment was prepared according to the method described in JP-A No. 11-5919 (Japanese Patent No. 3003664) 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, and then the solvent was removed by steam distillation, followed by a 2% aqueous chloride solution, The resultant was purified with a 2% 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. This is designated as Pigment 11.

(Comparative Synthesis Example 9)
A pigment was prepared according to the method described in JP-A-3-255456 (Patent No. 3005052) and Synthesis Example 2. That is, 10 parts of the wet cake prepared in Synthesis Example 1 on the left 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. This is designated as Pigment 12.

(Comparative Synthesis Example 10)
A pigment was prepared according to the method described in JP-A No. 11-5919 (Japanese Patent No. 3003664) and Example 4. That is, the wet cake obtained in Comparative Synthesis Example 7 was washed with 5% hydrochloric acid, washed with water and filtered until neutral, and dried. Further, this was dispersed with THF in a ball mill for 10 hours, filtered and dried to obtain a pigment powder. This is designated as Pigment 13.

(Comparative Synthesis Example 11)
A pigment was prepared according to the method described in JP-A No. 5-134437 (Patent No. 3196260), Production Example 1 and Production Example 2.
That is, 97.5 g of phthalodinitrile is added to 750 ml of α-chloronaphthalene, and then 22 ml of titanium tetrachloride is added dropwise under a nitrogen atmosphere. After dropping, the temperature was raised, and the mixture was reacted at 200 to 220 for 3 hours with stirring, then allowed to cool, filtered hot at 100 to 130, and washed with 200 ml of α-chloronaphthalene heated to 100 ° C. Furthermore, the hot-washing process (100 degreeC, 1 hour) was performed 3 times with 200 ml N-methylpyrrolidone. Subsequently, the suspension was washed with 300 ml of methanol at room temperature, and further washed with 500 ml of methanol for 1 hour for 3 hours. This is designated as phthalocyanine 1.

Next, phthalocyanine 1 was ground in a sand grind mill for 20 hours, then placed in a suspension of 400 ml of water and 40 ml of o-dichlorobenzene, and heat-treated at 60 ° C. for 1 hour. This is designated as phthalocyanine 2.
Further, according to Example 1 of JP-A-5-134437, 6 parts by weight and 4 parts by weight of phthalocyanine 1 and phthalocyanine 2 were mixed, 200 parts by weight of n-propanol was added, and pulverized with a sand grind mill for 10 hours. Atomization and dispersion treatment was performed. This was dried to obtain phthalocyanine powder. This is designated as Pigment 14.

A portion of titanyl phthalocyanine (water paste) before crystal conversion prepared in Comparative Synthesis Example 1 was diluted with ion-exchanged water to about 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 axis of the 30 individuals measured was determined and used 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 immediately before filtration in Comparative Synthesis Example 1 and Synthesis Example 1 was diluted with tetrahydrofuran so as to be 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.
From Table 1, the pigment 1 produced in Comparative Synthesis Example 1 not only has a large average particle size but also contains coarse particles. On the other hand, it can be seen that the pigment 2 produced in Synthesis Example 1 has not only a small average particle size but also almost the same size of each primary particle.

Moreover, the X-ray diffraction spectrum of the pigments produced in Comparative Synthesis Examples 2 to 12 was measured by the same method as described above, and it was confirmed that they were the same as the spectra described in the respective publications. Table 2 shows the characteristics of the respective X-ray diffraction spectra and the peak positions of the X-ray diffraction spectra of the pigments obtained in Comparative Synthesis Example 1 and Synthesis Examples 1 to 3.
The peak intensity at 26.3 ° in Table 2 is the ratio of the peak intensity at 27.2 ° to the peak intensity at 26.3 ° as described above. In this calculation, when the peak at 26.3 ° was not clearly observed as shown in FIG. 18, the calculation was performed with the peak intensity = 0.

(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. Was dispersed for 30 minutes to prepare a dispersion (referred to as Dispersion 1).

(Dispersion Preparation Examples 2 to 15)
In place of Pigment 1 used in Dispersion Preparation Example 1, pigments 2 to 15 prepared in Synthesis Examples 1 to 3 and Comparative Synthesis Examples 2 to 12 were used, respectively, and dispersed under the same conditions as Dispersion Preparation Example 1. Liquids were prepared (corresponding to the pigment numbers, dispersions 2 to 15, respectively).
(Dispersion Preparation Example 16)
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. In the filtration, a pump was used and filtration was performed in a pressurized state (referred to as Dispersion 16).

(Dispersion Preparation Example 17)
Dispersion was performed by pressure filtration in the same manner as in Dispersion Preparation Example 16 except that the filter used in Dispersion Preparation Example 16 was changed to Advantech's Cotton Wind Cartridge Filter and TCW-3-CS (effective pore size 3 μm). A liquid was prepared (referred to as dispersion liquid 17).
(Dispersion Preparation Example 18)
Dispersion was performed by pressure filtration in the same manner as in Dispersion Preparation Example 16 except that the filter used in Dispersion Preparation Example 15 was changed to a cotton wind cartridge filter manufactured by Advantech, TCW-5-CS (effective pore size 5 μm). A liquid was prepared (referred to as dispersion 18).
(Dispersion Preparation Example 19)
Dispersion was carried out by changing the dispersion conditions in Dispersion Preparation Example 1 as follows (referred to as Dispersion 19).
Rotor rotation speed: 1000 r. p. m. For 20 minutes.
(Dispersion Preparation Example 20)
The dispersion prepared in Dispersion Preparation Example 19 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 with Horiba: CAPA-700. The results are shown in Table 3.

(Comparative Example 1)
A conductive layer coating solution, a charge blocking 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 (JIS1050) having a diameter of 60 mm. A conductive layer, a 0.5 μm charge blocking layer, a charge generation layer, and a 23 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 transmittance of the charge generation layer is 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 polyethylene without the charge generation layer applied Using the terephthalate film as a comparative control, the transmittance at 780 nm was evaluated with a commercially available spectrophotometer (Shimadzu: UV-3100).

◎ Conductive layer coating solution Tin oxide-antimony oxide powder (specific resistance: 10 ⁶ Ω · cm, average primary particle size 0.4 μm)
140 parts alkyd resin [Beckolite M6401-50-S (solid content 50%),
Dainippon Ink & Chemicals, Inc.] 33.6 parts Melamine resin [Super Becamine L-121-60 (solid content 60%),
Dai Nippon Ink Chemical Co., Ltd.] 18.7 parts 2-butanone 100 parts In the above composition, the ratio of alkyd resin to melamine resin is 6/4 weight ratio.
Charge blocking layer Alcohol-soluble nylon (Toray: Amilan CM8000) 4 parts Methanol 70 parts n-Butanol 30 parts Charge transfer layer coating liquid Dispersion 1 prepared above 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

(Comparative Examples 2 to 14 and Examples 1 to 3 and Reference Examples 1 and 2 )
A photoconductor was prepared in the same manner as in Comparative Example 1 except that the charge generation layer coating solution (Dispersion 1) used in Comparative Example 1 was changed to Dispersions 2 to 19, respectively. As in Comparative Example 1, the thickness of the charge generation layer was adjusted so that the transmittance at 780 nm was 20% when all the coating liquids were used. Table 4 shows the correspondence between the example numbers and the dispersions used.

(Comparative Example 15)
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the charge blocking layer was not provided.

(Comparative Example 16)
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the conductive layer was not provided.
(Comparative Example 17)
In Example 1, a 0.5 μm charge blocking layer and a charge generation layer were formed in the same manner as in Example 1 except that a 10 μm undercoat layer was formed using the following undercoat layer coating solution instead of the 10 μm conductive layer. A 23 μm charge transport layer was provided to produce a photoreceptor.
◎ Undercoat layer coating solution Titanium oxide fine particles (specific resistance: 1.5 × 10 ¹⁰ Ω · cm, average primary particle size: 0.5 μm) 84 parts Alkyd resin [Beckolite M6401-50-S (solid content 50% ),
Dainippon Ink & Chemicals, Inc.] 33.6 parts Melamine resin [Super Becamine L-121-60 (solid content 60%),
Dainippon Ink & Chemicals, Inc.] 18.7 parts 2-butanone 100 parts In the above composition, the ratio of alkyd resin to melamine resin is 6/4 weight ratio.

(Example 6)
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the thickness of the charge blocking layer was 0.3 μm.
(Example 7)
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the thickness of the charge blocking layer was 1.0 μm.
(Example 8)
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the thickness of the charge blocking layer was 2.0 μm.
Example 9
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the thickness of the charge blocking layer was 0.1 μm.

(Example 10)
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the conductive layer coating solution was changed to one having the following composition.
◎ Conductive layer coating solution Indium oxide (specific resistance: 10 ⁴ Ω · cm) 144 parts Alkyd resin [Beckolite M6401-50-S (solid content 50%),
Dainippon Ink & Chemicals, Inc.] 33.6 parts Melamine resin [Super Becamine L-121-60 (solid content 60%),
Dai Nippon Ink Chemical Co., Ltd.] 18.7 parts 2-butanone 300 parts In the above composition, the ratio of alkyd resin to melamine resin is 6/4 weight ratio.

(Example 11)
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the conductive layer coating solution was changed to one having the following composition.
◎ Conductive layer coating liquid Conductive titanium oxide (specific resistance: 7.1 × 10 ⁴ Ω · cm) 84 parts Alkyd resin [Beckolite M6401-50-S (solid content 50%),
Dainippon Ink & Chemicals, Inc.] 33.6 parts Melamine resin [Super Becamine L-121-60 (solid content 60%),
Dai Nippon Ink Chemical Co., Ltd.] 18.7 parts 2-butanone 100 parts In the above composition, the ratio of alkyd resin to melamine resin is 6/4 weight ratio.

Example 12
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the conductive layer coating solution was changed to one having the following composition.
Conductive layer coating solution Conductive titanium oxide (specific resistance: 50 Ω · cm) 42 parts Titanium oxide fine particles (specific resistance: 1.5 × 10 ¹⁰ Ω · cm) 42 parts Alkyd resin [Beckolite M6401-50-S ( Solid content 50%),
Dainippon Ink & Chemicals, Inc.] 33.6 parts Melamine resin [Super Becamine L-121-60 (solid content 60%),
Dai Nippon Ink Chemical Co., Ltd.] 18.7 parts 2-butanone 100 parts In the above composition, the ratio of alkyd resin to melamine resin is 6/4 weight ratio.

(Example 13)
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the charge blocking layer coating solution was changed to one having the following composition.
Charge blocking layer coating solution Alkyd resin [Beckolite M6401-50-S (solid content 50%),
Dainippon Ink & Chemicals, Inc.] 33.6 parts Melamine resin [Super Becamine L-121-60 (solid content 60%),
Dainippon Ink & Chemicals, Inc.] 18.7 parts 2-butanone 500 parts

(Example 14)
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the conductive layer coating solution was changed to one having the following composition.
◎ Conductive layer coating solution Tin oxide-antimony oxide powder (specific resistance: 10 ⁶ Ω · cm, average primary particle size 0.4 μm)
140 parts alkyd resin [Beckolite M6401-50-S (solid content 50%),
Dainippon Ink and Chemicals Co., Ltd.] 22.4 parts Melamine resin [Super Becamine L-121-60 (solid content 60%),
Dainippon Ink & Chemicals, Inc.] 28 parts 2-butanone 100 parts The ratio of alkyd resin to melamine resin is 4/6 weight ratio.

(Example 15)
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the conductive layer coating solution was changed to one having the following composition.
◎ Conductive layer coating solution Tin oxide-antimony oxide powder (specific resistance: 10 ⁶ Ω · cm, average primary particle size 0.4 μm)
140 parts alkyd resin [Beckolite M6401-50-S (solid content 50%),
Dainippon Ink & Chemicals, Inc.] 28 parts Melamine resin [Super Becamine L-121-60 (solid content 60%),
Manufactured by Dainippon Ink & Chemicals, Inc.] 23.3 parts 2-butanone 100 parts The ratio of alkyd resin to melamine resin is 5/5 weight ratio.

(Example 16)
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the conductive layer coating solution was changed to one having the following composition.
◎ Conductive layer coating solution Tin oxide-antimony oxide powder (specific resistance: 10 ⁶ Ω · cm, average primary particle size 0.4 μm)
140 parts alkyd resin [Beckolite M6401-50-S (solid content 50%),
Dainippon Ink & Chemicals, Inc.] 39.2 parts Melamine resin [Super Becamine L-121-60 (solid content 60%),
Dainippon Ink & Chemicals, Inc.] 14 parts 2-butanone 100 parts The ratio of alkyd resin to melamine resin is 7/3 weight ratio.

(Example 17)
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the conductive layer coating solution was changed to one having the following composition.
◎ Conductive layer coating solution Tin oxide-antimony oxide powder (specific resistance: 10 ⁶ Ω · cm, average primary particle size 0.4 μm)
140 parts alkyd resin [Beckolite M6401-50-S (solid content 50%),
Dainippon Ink & Chemicals, Inc.] 44.8 parts Melamine resin [Super Becamine L-121-60 (solid content 60%),
Dai Nippon Ink Chemical Co., Ltd.] 9.3 parts 2-butanone 100 parts The ratio of alkyd resin to melamine resin is 8/2 weight ratio.

(Example 18)
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the conductive layer coating solution was changed to one having the following composition.
◎ Conductive layer coating solution Tin oxide-antimony oxide powder (specific resistance: 10 ⁶ Ω · cm, average primary particle size 0.4 μm)
140 parts alkyd resin [Beckolite M6401-50-S (solid content 50%),
Dainippon Ink & Chemicals, Inc.] 50.4 parts Melamine resin [Super Becamine L-121-60 (solid content 60%),
Dainippon Ink & Chemicals, Inc.] 4.7 parts 2-butanone 100 parts The ratio of alkyd resin to melamine resin is 9/1 weight ratio.

(Example 19)
In Example 1, a photoconductor was prepared in the same manner as in Example 1 except that the conductive layer coating solution was changed to one having the following composition.
◎ Conductive layer coating solution Tin oxide-antimony oxide powder (specific resistance: 10 ⁶ Ω · cm, average primary particle size 0.4 μm)
140 parts Alcohol-soluble nylon (Toray: Amilan CM8000) 24 parts Methanol 300 parts n-Butanol 130 parts

(Examples 20 to 38 [Examples 23 and 24 are Reference Examples 3 and 4] and Comparative Examples 18 to 34)
The electrophotographic photosensitive members of Examples 1 to 19 and Comparative Examples 1 to 17 produced as described above are mounted on the electrophotographic apparatus shown in FIG. 12, and an image exposure light source is a semiconductor laser of 780 nm (image writing by a polygon mirror). Using a contact-type charging roller as a charging member and a transfer belt as a transfer member, continuous 200,000 sheets were printed using a chart with a writing rate of 6% under the following charging conditions. Subsequent white solid and halftone images were output and evaluated, and the presence or absence of background stains, the presence or absence of moire, and the image density were confirmed. The background image evaluation was carried out in 4 stages. Very good ones were indicated by 、, good ones were indicated by ○, slightly inferior ones were indicated by Δ, and very bad ones were indicated by ×.
These evaluations were performed in three environments of 22 ° C.-55% RH, 10 ° C.-15% RH, and 30 ° C.-90% RH. The above results are shown in Tables 4-6.
Charging conditions:
DC bias: -900V
AC bias: 2.0 kV (Peak to peak), frequency: 2.0 kHz

(Example 39)
A photoconductor was prepared in the same manner as in Example 1 except that the charge transport layer coating solution in Example 1 was changed to one having the following composition.
◎ Charge transport layer coating solution Polymer charge transport material having the following composition (weight average molecular weight: about 143000) 10 parts
0.5 parts of additive with the following structure
100 parts methylene chloride

(Example 40)
A photoconductor was prepared in the same manner as in Example 1 except that the thickness of the charge transport layer in Example 1 was 18 μm, a protective layer coating solution having the following composition was applied and dried on the charge transport layer, and a 5 μm protective layer was provided. Produced.
◎ Protective layer coating solution Polycarbonate (TS2050: manufactured by Teijin Chemicals Ltd.) (viscosity average molecular weight: 50,000)
10 parts Charge transport material of the following structural formula 7 parts
Alumina fine particles (specific resistance: 2.5 × 10 ¹² Ω · cm, average primary particle size: 0.4 μm)
4 parts Cyclohexanone 500 parts Tetrahydrofuran 150 parts

(Example 41)
A photoconductor was prepared in the same manner as in Example 40 except that the alumina fine particles in the protective layer coating solution in Example 40 were changed to the following.
Titanium oxide fine particles (specific resistance: 1.5 × 10 ¹⁰ Ω · cm, average primary particle size: 0.5 μm) 4 parts

(Example 42)
A photoconductor was prepared in the same manner as in Example 40 except that the alumina fine particles in the protective layer coating solution in Example 40 were changed to the following.
Tin oxide-antimony oxide powder (specific resistance: 10 ⁶ Ω · cm, average primary particle size 0.4 μm)
4 copies

(Example 43)
A photoconductor was prepared in the same manner as in Example 1 except that the thickness of the charge transport layer in Example 1 was 18 μm, a protective layer coating solution having the following composition was applied and dried on the charge transport layer, and a 5 μm protective layer was provided. Produced.
◎ Protective layer coating solution Methyltrimethoxysilane 100 parts 3% acetic acid 20 parts Charge transporting compound with the following structure 35 parts
Antioxidant (Sanol LS2626: Sankyo Chemical Co., Ltd.) 1 part Curing agent (dibutyltin acetate) 1 part 2-propanol 200 parts

(Example 44)
A photoconductor was prepared in the same manner as in Example 1 except that the thickness of the charge transport layer in Example 1 was 18 μm, a protective layer coating solution having the following composition was applied and dried on the charge transport layer, and a 5 μm protective layer was provided. Produced.
◎ Protective layer coating solution Methyltrimethoxysilane 100 parts 3% acetic acid 20 parts Charge transporting compound with the following structure 35 parts
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 (Dibutyltin acetate) 1 part 2-propanol 200 parts

(Examples 45-51)
The electrophotographic photosensitive members of Example 1 and Examples 39 to 44 produced as described above are mounted on the electrophotographic apparatus shown in FIG. 12, and the image exposure light source is a semiconductor laser of 780 nm (image writing by a polygon mirror). As a charging member, a charging member for close placement in which an insulating tape with a thickness of 50 μm is wound around both ends of a charging roller as shown in FIG. 13 (the gap between the surface of the photosensitive member and the charging member is 50 μm) and the following charging conditions are used. Then, continuous printing of 200,000 sheets was performed using a chart with a writing rate of 6%. Thereafter, solid white and halftone images were output, and the presence or absence of background stains, the presence or absence of moire, and the image density were confirmed (the test environment was 22 ° C.-55% RH). The background stain was evaluated in 4 stages. Very good ones were indicated by 、, good ones were indicated by ○, slightly inferior ones were indicated by Δ, and very bad ones were indicated by ×. Further, the amount of abrasion of the photosensitive layer after printing 200,000 sheets (when the protective layer is provided, the amount of abrasion of the protective layer) was measured. The results are shown in Table 7.
Charging conditions:
DC bias: -900V
AC bias: 2.2 kV (Peak to peak), frequency: 2.0 kHz

(Example 52)
In Example 45, after a paper feeding test of 200,000 sheets, a halftone image was output in an environment of 30 ° C. and 90% RH, and image evaluation was performed.

(Example 53)
The charging member in Example 45 was changed from a charging member for close placement to a scorotron charger, and the surface potential of the non-image portion of the photoreceptor was set to be the same (−900 V) as in Example 45. 200,000 sheets were tested in the same manner as in Example 45 without changing other conditions. After the paper passing test, a halftone image was output in a 30 ° C.-90% RH environment in the same manner as in Example 52, and image evaluation was performed.

(Example 54)
The charging member in Example 45 was changed from the proximity charging member to the contact charging member (no gap), and the charging conditions were set to the same conditions as in Example 45. 200,000 sheets were tested in the same manner as in Example 45 without changing other conditions. After the paper passing test, a halftone image was output in a 30 ° C.-90% RH environment in the same manner as in Example 52, and image evaluation was performed.

(Example 55)
Evaluation was performed in the same manner as in Example 54 except that the charging conditions in Example 54 were changed as follows.
Charging conditions:
DC bias: −1600 V (surface potential of the non-image portion of the photoreceptor in the initial state is −900 V)
AC bias: None

(Example 56)
Evaluation was performed in the same manner as in Example 45 except that the charging conditions in Example 45 were changed as follows. After a paper feeding test of 200,000 sheets, a halftone image was output in a 30 ° C.-90% RH environment in the same manner as in Example 52, and image evaluation was performed.
Charging conditions:
DC bias: −1600 V (surface potential of the non-image portion of the photoreceptor in the initial state is −900 V)
AC bias: None

(Example 57)
Evaluation was performed in the same manner as in Example 45 except that the gap of the charging member (proximity charging roller) used in Example 45 was changed to 70 μm. After a paper feeding test of 200,000 sheets, a halftone image was output in a 30 ° C.-90% RH environment in the same manner as in Example 52, and image evaluation was performed.

(Example 58)
Evaluation was performed in the same manner as in Example 45 except that the gap of the charging member (proximity charging roller) used in Example 45 was changed to 100 μm. After a paper feeding test of 200,000 sheets, a halftone image was output in a 30 ° C.-90% RH environment in the same manner as in Example 52, and image evaluation was performed.

(Example 59)
Evaluation was performed in the same manner as in Example 45 except that the gap of the charging member (proximity charging roller) used in Example 45 was changed to 150 μm. After a paper feeding test of 200,000 sheets, a halftone image was output in a 30 ° C.-90% RH environment in the same manner as in Example 52, and image evaluation was performed.

(Example 60)
In Example 46, after a paper passing test of 200,000 sheets, a halftone image was output under a 30 ° C.-90% RH environment, and image evaluation was performed.

(Example 61)
In Example 47, after a paper passing test of 200,000 sheets, a halftone image was output under a 30 ° C.-90% RH environment, and image evaluation was performed.
Table 8 shows the evaluation results in Examples 52 to 61 described above.

(Comparative Example 35)
A photoconductor having the same composition as that of Comparative Example 6 was produced by changing the aluminum cylinder of Comparative Example 6 to one having a diameter of 30 mm.
(Comparative Example 36)
A photoconductor having the same composition as that of Comparative Example 7 was prepared by changing the aluminum cylinder of Comparative Example 7 to one having a diameter of 30 mm.
(Comparative Example 37)
A photoconductor having the same composition as that of Comparative Example 8 was produced by changing the aluminum cylinder of Comparative Example 8 to one having a diameter of 30 mm.

(Example 62)
A photoconductor having the same composition as in Example 1 was produced by replacing the aluminum cylinder of Example 1 with one having a diameter of 30 mm.
( Reference Example 5 )
The aluminum cylinder of Example 4 was changed to one having a diameter of 30 mm, and a photoconductor having the same composition as that of Example 4 was produced.
(Comparative Example 38)
The aluminum cylinder of Comparative Example 15 was changed to one having a diameter of 30 mm, and a photoconductor having the same composition as Comparative Example 15 was produced.
(Comparative Example 39)
The aluminum cylinder of Comparative Example 16 was changed to one having a diameter of 30 mm, and a photoconductor having the same composition as Comparative Example 16 was produced.
(Comparative Example 40)
The aluminum cylinder of Comparative Example 17 was changed to one having a diameter of 30 mm, and a photoconductor having the same composition as Comparative Example 17 was produced.

(Example 64 , Reference Example 6 and Comparative Examples 41 to 46)
The photoconductors of Example 62 , Reference Example 5 and Comparative Examples 35 to 40 manufactured as described above are mounted on one electrophotographic apparatus process cartridge together with the charging member, and further mounted on the full-color electrophotographic apparatus shown in FIG. did. The four image forming elements were subjected to a 200,000 full-color image passing test under the process conditions shown below. Thereafter, confirmation of the presence or absence of soiling and halftone image evaluation were performed (the test environment was 22 ° C.-55% RH). In addition, character omission and background stain evaluation were performed in four stages, and very good ones were indicated by ◎, good ones were indicated by ○, slightly inferior ones by Δ, and very bad ones by x. The above results are shown in Table 9.
Charging conditions:
DC bias: -800V
AC bias: 2.2 kV (Peak to peak), frequency 2.0 kHz
Charging member: the same as that used in Example 2 Writing: 780 nm LD (using polygon mirror)

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.
(Measurement Example 1)
A pigment prepared in the same manner as the pigment described in JP-A-61-239248 (having a maximum diffraction peak at 7.5 °) was used as the pigment obtained in Comparative Synthesis Example 1 (minimum angle 7.3 °). Weight% was added and mixed in a mortar, and the X-ray diffraction spectrum was measured in the same manner as before. The X-ray diffraction spectrum of Measurement Example 1 is shown in FIG.
(Measurement example 2)
3 was prepared in the same manner as the pigment described in JP-A-61-239248 (having a maximum diffraction peak at 7.5 °) as the pigment obtained in Comparative Synthesis Example 2 (minimum angle 7.5 °). Weight% was added and mixed in a mortar, and the X-ray diffraction spectrum was measured in the same manner as before. The X-ray diffraction spectrum of Measurement Example 2 is shown in FIG.

In the spectrum of FIG. 21, it can be seen that there are two independent peaks at 7.3 ° and 7.5 ° on the low angle side, and at least the peaks at 7.3 ° and 7.5 ° are different. . On the other hand, in the spectrum of FIG. 22, 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.

It is explanatory drawing which shows an example of the laminated constitution of the conventional photoreceptor. It is explanatory drawing which shows the other example of the laminated constitution of the conventional photoreceptor. It is a TEM image of a titanyl phthalocyanine crystal. It is a TEM image of the crystal | crystallization of the primary particle after crystal conversion. It is a TEM image of a titanyl phthalocyanine crystal when crystal conversion is performed in a short time. It is the photograph of the state of the dispersion liquid which fixed the dispersion condition of the pigment and shortened the dispersion time. It is the photograph of the state of the dispersion liquid which lengthened the dispersion time similarly. FIG. 8 is a graph of the state of the dispersion liquid of FIGS. It is sectional drawing which shows the structural example of the electrophotographic photoreceptor used for this invention. It is sectional drawing which similarly shows another structural example. It is sectional drawing which shows another example of a structure similarly. 1 is a schematic diagram for explaining an image forming apparatus of the present invention. It is explanatory drawing of an example of a proximity charging mechanism. It is explanatory drawing of another example of the image forming apparatus of this invention. It is explanatory drawing of an example of a process cartridge. 1 is a schematic view of an example of a tandem-type full-color image forming apparatus according to the present invention. 2 is an X-ray diffraction spectrum of a dry powder of an aqueous paste of titanyl phthalocyanine crystals. 3 is an X-ray diffraction spectrum of a titanyl phthalocyanine crystal obtained in Synthesis Example 2. FIG. 3 is an X-ray diffraction spectrum of a titanyl phthalocyanine crystal obtained in Comparative Synthesis Example 2. FIG. 3 is an X-ray diffraction spectrum of a titanyl phthalocyanine crystal obtained in Comparative Synthesis Example 3. FIG. 3 is an X-ray diffraction spectrum of Measurement Example 1. 4 is an X-ray diffraction spectrum of Measurement Example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Filler dispersion layer 3 Resin layer 4 Photosensitive layer 5 Conductive layer 6 Charge blocking layer 7 Charge generation layer 8 Charge transport layer 9 Protective layer 11, 41, 51, 61C, 61M, 61Y, 61K Photoconductor 12 Static elimination Lamp 13, 53 Charging roller 15, 54 Image exposure unit 16 Development unit 17 Pre-transfer charger 18 Registration roller 19 Transfer paper 20, 45 Transfer charger 21 Separation charger 22 Separation claw 23 Pre-cleaning charger 24 Fur brush 25, 47, 55 Cleaning brush 31 Gap forming member 32 Core metal 33 Image forming area 34 Non-image forming area 42a, 42b Driving roller
43 Charger 44 Image exposure source 46 Exposure before cleaning 48 Static elimination light source 56 Development roller 57 Transfer roller 62C, 62M, 62Y, 62K Charging member 63C, 63M, 63Y, 63K Laser beam 64C, 64M, 64Y, 64K Development member 65C, 65M , 65Y, 65K Cleaning member 66C, 66M, 66Y, 66K Image forming element 67 Transfer paper 68 Paper feed roller 70 Transfer conveyance belt 71C, 71M, 71Y, 71K Transfer brush

Claims (25)

In an electrophotographic photosensitive member in which at least a conductive layer, a charge blocking layer, and a photosensitive layer are sequentially laminated on a conductive support, a Bragg angle 2θ with respect to a characteristic X-ray of CuKα (wavelength 1.542 mm) is included in the photosensitive layer. As a diffraction peak (± 0.2 °), it has a maximum diffraction peak at least 27.2 °, and further has main peaks at 9.4 °, 9.6 °, and 24.0 °, the lowest angle. A crystal form having a peak at 7.3 ° as a side diffraction peak, no peak between the 7.3 ° peak and the 9.4 ° peak, and a peak at 26.3 °, It contains a titanyl phthalocyanine crystal having an average primary particle size of 0.25 μm or less, and the titanyl phthalocyanine crystal has a diffraction peak (± 0.2 °) of Bragg angle 2θ with respect to the characteristic X-ray of CuKα at least 7. 0 Amorphous titanyl phthalocyanine or low crystalline titanyl phthalocyanine having a maximum diffraction peak at 7.5 ° and a half-width of the diffraction peak of 1 ° or more and an average primary particle size of 0.1 μm or less is present in water. An electrophotographic photosensitive film characterized by being subjected to crystal transformation with an organic solvent under the condition that the primary particles after the crystal transformation are separated and filtered from an organic solvent before growing to an average particle size larger than 0.25 μm. body.   2. The electrophotographic image according to claim 1, wherein the titanyl phthalocyanine crystal has a peak intensity of 26.3 ° in a range of 0.1 to 5% with respect to a peak intensity of a maximum diffraction peak of 27.2 °. Photoconductor.   3. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer has a laminated structure of a charge generation layer and a charge transport layer. The electrophotographic photosensitive member according to claim 1 , wherein the titanyl phthalocyanine crystal is synthesized using a raw material not containing a halide. The electrophotographic photosensitive member according to claim 1, wherein the charge blocking layer is made of an insulating material and has a thickness of less than 2.0 μm. 6. The electrophotographic photosensitive member according to claim 5 , wherein the insulating material is polyamide. 7. The electrophotography according to claim 1, wherein the moire preventing layer contains an inorganic pigment and a binder resin, and a volume ratio of the two is in a range of 1/1 to 3/1. Photoconductor. The electrophotographic photosensitive member according to claim 7 , wherein the binder resin is a thermosetting resin. 9. The electrophotographic photosensitive member according to claim 8 , wherein the thermosetting resin is an alkyd / melamine resin mixture.   The electrophotographic photosensitive member according to claim 9, wherein a mixing ratio of the alkyd resin and the melamine resin is in a range of 5/5 to 8/2 (weight ratio). The electrophotographic photosensitive member according to claim 1, further comprising a protective layer on the photosensitive layer. The electrophotographic photosensitive member according to claim 11 , wherein the protective layer contains an inorganic pigment or metal oxide having a specific resistance of 10 ¹⁰ Ω · cm or more. 13. The electrophotographic photoreceptor according to claim 12 , wherein the metal oxide is any one of alumina, titanium oxide, and silica having a specific resistance of 10 ¹⁰ Ω · cm or more. The electrophotographic photosensitive member according to claim 13 , wherein the metal oxide is α-alumina having a specific resistance of 10 ¹⁰ Ω · cm or more. The electrophotographic photosensitive member according to claim 11 , wherein the protective layer contains a polymer charge transport material. The electrophotographic photosensitive member according to claim 11 , wherein the binder resin of the protective layer has a crosslinked structure. The electrophotographic photosensitive member according to claim 16, further comprising a charge transporting site in the structure of the binder resin having the crosslinked structure. The image forming apparatus comprising at least a charging unit, an exposure unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is any one of claims 1 to 17. An image forming apparatus characterized by being a body. 19. The image forming apparatus according to claim 18 , 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. The image forming apparatus according to claim 18 , wherein a contact charging method is used as a charging unit of the image forming apparatus. The image forming apparatus according to claim 18 , wherein a non-contact proximity arrangement method is used as a charging unit of the image forming apparatus. The image forming apparatus according to claim 21 , wherein a gap between a charging member used for the charging unit and the photosensitive member is 100 μm or less. 23. The image forming apparatus according to claim 20 , wherein an alternating superimposed voltage is applied as a charging unit of the image forming apparatus. The image forming apparatus includes an apparatus main body in which a photosensitive member and at least one unit selected from a charging unit, an exposure unit, a developing unit, and a cleaning unit are integrated, and a removable cartridge. The image forming apparatus according to any one of claims 18 to 23 . An image forming apparatus process cartridge in which at least one means selected from a charging means, an exposure means, a developing means, and a cleaning means and an electrophotographic photosensitive member are integrated, wherein the electrophotographic photosensitive member is defined in claims 1 to 17 . A process cartridge for an image forming apparatus, which is the electrophotographic photosensitive member according to any one of the above.