JP2009047731A - Electrophotographic photoreceptor, and image forming apparatus and process cartridge for image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which avoids staining, even after repeated use and achieves stable image formation, and to provide an image forming apparatus and a process cartridge for an image forming apparatus that uses the same. <P>SOLUTION: The electrophotographic photoreceptor is obtained by sequentially disposing on a conductive support (31) a photosensitive layer (33), containing titanylphthalocyanine crystals having at least a maximum diffraction peak at 26.2° and also having peaks at 9.3°, 10.5°, 13.2°, 15.1°, 15.6°, 16.1°, 20.7°, 23.2°, 27.1° and 28.3° as diffraction peaks (±0.2°) at the Bragg angle 2θ for a characteristic X-ray of CuKα (wavelength 1.542 Å), and a protective layer (34), comprising a resin cured product formed by curing a trifunctional or higher functionality radical polymerizable monomer which does not have a charge-transport structure and a monofunctional radical polymerizable compound having a charge-transport structure. The image forming apparatus and the process cartridge for an image forming apparatus are configured by using the electrophotographic photoreceptor. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to electrophotographic technology, and more specifically, a photosensitive layer containing a titanyl phthalocyanine crystal having a specific crystal structure and a protective layer made of a cured resin having a specific structure are sequentially provided. The present invention relates to an electrophotographic photosensitive member capable of forming a stable and high-quality image (for example, high-speed, full-color printing), an image forming apparatus using the electrophotographic photosensitive member, and a process cartridge for the image forming apparatus. .
The electrophotographic photosensitive member may be hereinafter referred to as “electrostatic latent image carrier”, “photosensitive member”, or “photoconductive insulator”.

  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 also rapidly progressing.

  Such a digital image forming apparatus is required to improve its function year by year, and of course not only high durability and high stability but also high image quality. For high-speed colorization, a tandem color system that uses multiple image forming elements, each of which is equipped with a single member necessary for image formation, such as charging, exposure, development, cleaning, and charge removal, on a single photoconductor Image forming devices are preferred and are now mainstream. A tandem color image forming apparatus is usually equipped with image forming elements for yellow, magenta, cyan, and black, and each toner image is created in parallel with four image forming elements, and a transfer body (transfer paper) or intermediate A color image is created at high speed by overlapping on the transfer body.

  For this reason, if the photosensitive member and the members around it are not 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. As a matter of fact, 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, along with the reduction in diameter, it is an issue of this technique to extend the life of the photoconductor as compared to the conventional photoconductor.

There are two rate-determining processes in the life of the photoreceptor, one is electrostatic fatigue, and the other is surface layer wear. Both are major problems for the current mainstream organic photoreceptors.
The former (electrostatic fatigue) is a change in the surface potential (charge potential and exposed portion potential) of the photoreceptor due to repeated image forming processes such as charging and exposure. Decrease or increase in the exposed portion potential (sometimes referred to as residual potential) becomes a problem.
The latter (abrasion of the surface layer) is a phenomenon in which a layer located on the outermost surface constituting the photoconductor is mechanically worn by sliding 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, an electrophotographic image forming apparatus is entering the printing field by realizing high speed, and high image quality and high stability are demanded. With regard to the former (higher image quality), 600 dpi is the lowest quality as the resolution in image writing, and the resolution has been greatly improved. The latter (high stability) makes it possible to add various and different information one by one to a part of the output manuscript in a field that is good at mass printing, taking advantage of the feature of electrophotography that manuscript information can be printed directly. It has become. In other words, a large amount of writing and development is performed in which the same document is processed in a very large amount and at the same time, slightly different information is input for each sheet, so that stability as a system is extremely required. Became. 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 are central to image formation, and a photoreceptor that always performs an associated operation with other members during the image forming operation holds the most important key. With every vigorous development of photoreceptors so far, several techniques are being completed with regard to photoreceptor electrostatic properties and surface wear.
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. These all lead to a reduction in hazards added to the photoconductor, and allowance is also created in the photoconductor 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, the biggest problem is that the cause of the abnormal image is the photoconductor.
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 generated on the surface of the photoreceptor, and the other is an abnormal image caused by electrostatic fatigue of the photoreceptor. 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 photoreceptor itself, but the most serious problem at present is background contamination in reversal development (negative / positive development).

  The causes of the above-mentioned background contamination include 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. Etc. 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.

As a method for dealing with the electrostatic fatigue of the photosensitive layer, for example, titanyl phthalocyanine (abbreviated as TiOPc) described in Patent Documents 1 to 5 and the like can be used. Since TiOPc exhibits high sensitivity with respect to light having a long wavelength of 600 to 800 nm, TiOPc is extremely important and useful as a photoconductor material for an electrophotographic printer or digital copying machine whose light source is an LED or LD.
However, these techniques are not sufficient for long-term repeated use.

  Considering the essence of scumming, the fundamental solution is to suppress the charge injection property from the support, but the charge injection property depends on the electric field strength applied to the photoconductor. The amount of charge injection increases. In a normal electrophotographic process, the surface potential applied to the photoreceptor is given a constant surface potential. Therefore, after repeated use of the photoreceptor, the surface layer is worn more than in the initial state, and the entire film thickness is reduced. For this reason, as the photoreceptor is used repeatedly, the applied electric field strength increases and the amount of charge injection increases. As described above, since electrostatic fatigue in repeated use also promotes this charge injection, the occurrence of scumming increases at an accelerated rate due to wear and electrostatic fatigue.

From such a viewpoint, attempts have been made to provide a surface protective layer on the surface of the photoreceptor. As a result, the wear rate on the surface of the photoreceptor can be reduced, and the rate of increase in electric field strength can also be suppressed. Techniques for improving the abrasion resistance of the photosensitive layer include (i) using a curable binder in the crosslinkable charge transport layer (see, for example, Patent Document 6), and (ii) using a polymer charge transport material. (For example, see Patent Document 7), (iii) those in which an inorganic filler is dispersed in a cross-linked charge transport layer (for example, see Patent Document 8), and the like. Furthermore, a photoreceptor containing a polyfunctional acrylate monomer cured product in order to improve the wear resistance and scratch resistance of (i) is also known (for example, see Patent Document 9).
It is also known to provide a charge transport layer formed using a coating liquid comprising a monomer having a carbon-carbon double bond, a charge transport material having a carbon-carbon double bond, and a binder resin (for example, , See Patent Document 10). Furthermore, a photosensitive layer containing a compound obtained by curing a hole transporting compound having two or more chain polymerizable functional groups in the same molecule is also known (see, for example, Patent Document 11).

The surface protection layer technology as described above improves wear resistance in repeated use of the photoconductor, reduces the rate of increase in electric field strength, and certainly reduces the occurrence of image defects due to the charge leak phenomenon. became.
However, new problems specific to the protective layer have also occurred. For example, since the amount of wear has been reduced, the amount of substances deposited on the surface during repeated use of the photoreceptor has increased, and as a result, abnormal images such as image blur have occurred. In this regard, the problem can be solved by improving the protective layer and using the photoconductor, for example, using a drum heater.

The further improvement of the surface protective layer and the development of the technique for using the photoconductor further improve the wear resistance of the photoconductor, and the life of the photoconductor is clearly extended. As a result, the photoconductor has been used for a long period of time that is unthinkable in the situation where the protective layer is not used, and could not be predicted in the category of image defects based on photoconductor wear and charge leakage. The so-called electrostatic fatigue of the photosensitive member has come to have a limited life.
From the above situation, a photoreceptor having excellent wear resistance and electrostatic characteristics that does not generate abnormal images such as background stains even after repeated use, particularly reversal development (negative / positive development), and an image using the same A forming device was desired.

Japanese Patent Publication No. 3-27897 Japanese Patent Publication No. 5-31137 Japanese Patent Publication No. 3-5745 JP-A-1-204969 Japanese Patent No. 2821765 JP 56-48637 A JP-A 64-1728 JP-A-4-281461 Japanese Patent No. 3262488 Japanese Patent No. 3194392 JP 2000-66425 A

An object of the present invention is to provide an electrophotographic photosensitive member capable of forming a stable image even when used repeatedly. Specifically, it is highly durable and has stable electrostatic characteristics that can reduce the occurrence of scumming in repeated use, prevent residual potential, and reduce the occurrence of dielectric breakdown when charging with a contact charging member or a nearby charging member. Another object of the present invention is to provide an electrophotographic photosensitive member.
Another object of the present invention is to provide an image forming apparatus that generates less abnormal images even when repeated image formation (output) is performed. Specifically, an object of the present invention is to provide a highly durable and stable image forming apparatus that solves background contamination and density reduction, which are the biggest problems during use in reversal development (negative / positive development). .
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.

In an electrophotographic photosensitive member using an organic pigment as a charge generation material, it is no exaggeration to say that its electrostatic characteristics depend on the charge generation material. In particular, in a polymorphic material such as a titanyl phthalocyanine crystal used in the present invention, the characteristics vary greatly depending on the crystal type.
Therefore, the present inventors have ensured good electrostatic characteristics by using a specific crystal type titanyl phthalocyanine crystal, and have studied to achieve the present invention based on this technology. That is, the present inventors diligently studied about a highly durable and highly reliable photoconductor technology for a photoconductor for an image forming apparatus using negative / positive development, and the following [1] to [17]. The inventors have found that the above-mentioned problems can be solved by the invention described in the above, and have reached the present invention. Hereinafter, the present invention will be specifically described.

[1]: In the electrophotographic photosensitive member formed by sequentially laminating at least a photosensitive layer and a protective layer on a conductive support,
The photosensitive layer has a maximum diffraction peak at 26.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray of CuKα (wavelength 1.542 mm), and 9.3 °. Also peaks at 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1 ° and 28.3 °. Resin cured product comprising a titanyl phthalocyanine crystal and a protective layer obtained by curing at least a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure This is solved by an electrophotographic photosensitive member characterized by comprising:

  [2]: The electrophotographic photosensitive member according to the above [1], wherein the photosensitive layer has a laminated structure including a charge generation layer and a charge transport layer.

  The laminated structure can improve the function of the photoreceptor. In addition, the margin for photoconductor design and material selection is increased.

  [3]: In the electrophotographic photosensitive member according to the above [1] or [2], the monofunctional radically polymerizable compound having the charge transporting structure is represented by the following general formula (1) or (2): It is characterized by being at least one compound.

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

  [4]: In the electrophotographic photoreceptor described in [3] above, the monofunctional radically polymerizable compound having the charge transporting structure is at least one compound represented by the following general formula (3). Features.

[In general formula (3), o, p and q are each an integer of 0 or 1, Ra represents a hydrogen atom or a methyl group, Rb and Rc are substituents other than a hydrogen atom, and an alkyl group having 1 to 6 carbon atoms. And a plurality of cases may be different. s and t represent an integer of 0 to 3. Za represents a single bond, a methylene group, an ethylene group, or a divalent group represented by the following formulas (4), (5), and (6). ]

  According to the above [3] and [4], the wear resistance and the electrical characteristics are well balanced and there is no decrease in sensitivity or increase in the residual potential even during long-term repeated use, and the electrical characteristics are maintained well.

  [5]: In the electrophotographic photosensitive member according to any one of claims 1 to 4, the protective layer made of the cured resin is cured and formed by at least one of a heating unit and a light energy irradiation unit. It is characterized by.

  By the heating or irradiation with light energy, a trifunctional or higher functional radical polymerizable monomer having no charge transporting structure and a monofunctional radical polymerizable compound having a charge transporting structure are easily cross-linked to form a cured resin. In addition, a surface layer is formed that maintains high durability even at high speeds and repeated use, and that provides high image quality.

  [6]: In the electrophotographic photosensitive member according to any one of the above [1] to [5], the titanyl phthalocyanine crystal contained in the photosensitive layer has a Bragg angle 2θ with respect to a characteristic X-ray (wavelength: 1.542Å) of CuKα. Diffraction peak (± 0.2 °) having a maximum diffraction peak at least 27.2 °, and further having major peaks at 9.4 °, 9.6 °, 24.0 °, and most As a diffraction peak on the low angle side, it has a peak at 7.3 °, no peak between the peak at 7.3 ° and the peak at 9.4 °, and no peak at 26.3 ° It is obtained by crystal conversion treatment of titanyl phthalocyanine crystal.

  [7]: The electrophotographic photosensitive member according to [6], wherein the crystal conversion treatment is performed by performing crystal conversion using an organic solvent.

  [8]: In the electrophotographic photosensitive member according to [7], the organic solvent used for the crystal conversion treatment includes at least one solvent selected from a ketone solvent or an ether solvent. To do.

  [9]: The electrophotographic photosensitive member according to any one of [6] to [8], wherein mechanical energy is applied in the crystal conversion treatment.

  If the titanyl phthalocyanine crystal (precursor) is subjected to a crystal conversion treatment according to [6] to [8], a titanyl phthalocyanine crystal having the specific crystal structure according to [1] used in the present invention can be reliably and easily obtained. Furthermore, if mechanical energy is applied in combination with the use of an organic solvent, crystal transition to a desired crystal form can be accelerated, and crystal conversion treatment can be efficiently performed.

[10]: In the electrophotographic photosensitive member according to any one of [6] to [9], a diffraction peak (± 0.2 °) at a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of the CuKα. As a diffraction peak on the lowest angle side, it has a maximum diffraction peak at least 27.2 °, a main peak at 9.4 °, 9.6 °, and 24.0 °. A titanyl phthalocyanine crystal having a peak at °, no peak between the peak at 7.3 ° and the peak at 9.4 °, and no peak at 26.3 °,
An amorphous titanyl phthalocyanine having a maximum diffraction peak at 7.0 to 7.5 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα is It is obtained by crystal conversion with an organic solvent in the presence.

  [11]: The electrophotographic photosensitive member according to [10] above, wherein the half-width of the diffraction peak at 7.0 to 7.5 ° of the amorphous titanyl phthalocyanine is 1 ° or more.

  [12]: In the electrophotographic photosensitive member according to [10] or [11], the organic solvent used for crystal conversion of the amorphous titanyl phthalocyanine is tetrahydrofuran, cyclohexanone, toluene, methylene chloride, carbon disulfide, ortho It contains at least one solvent selected from dichlorobenzene and 1,1,2-trichloroethane.

  If the amorphous titanyl phthalocyanine is crystal-converted by [10] to [11], a titanyl phthalocyanine crystal (precursor) can be obtained reliably and easily, and the crystal conversion treatment can be effectively performed by including the solvent.

  [13]: The electrophotographic photosensitive member according to any one of [10] to [12], wherein the amorphous titanyl phthalocyanine is synthesized without using a titanium halide.

  When amorphous titanyl phthalocyanine is synthesized without using a titanium halide, no impurities (halogenated and substituted titanyl phthalocyanine) remain in the product. If the titanyl phthalocyanine crystal having a crystal structure is used, charging performance and photosensitivity are not deteriorated, and electrostatic characteristics are satisfactorily maintained in long-term use, and abnormal images and the like are not generated.

  [14]: The above problem is that in the image forming apparatus comprising at least a charging unit, an exposure unit, a developing unit, a transfer unit, a fixing unit, and an electrophotographic photosensitive member, the electrophotographic photosensitive member has [1] to [13]. The image forming apparatus is characterized in that it is a photoconductor according to any one of the above.

  [15]: The above problem is that in the image forming apparatus in which a plurality of image forming elements including at least a charging unit, an exposure unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member are arranged, the electrophotographic photosensitive member is [1]. The image forming apparatus is characterized by being a photoreceptor according to any one of [13] to [13].

  [16]: The above problem is that the electrophotographic photosensitive member according to any one of [1] to [13] is integrated with at least one means selected from a charging means, an exposure means, a developing means, and a cleaning means. The image forming apparatus is characterized in that the cartridge is mounted and the cartridge is detachable from the apparatus main body.

  [17]: The object is to provide a process cartridge for an image forming apparatus 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. This is solved by a process cartridge for an image forming apparatus, wherein the body is the photosensitive member according to any one of [1] to [13].

According to the present invention, by including a titanyl phthalocyanine crystal having a specific crystal structure in the photosensitive layer, high sensitivity and good electrostatic characteristics are maintained even in long-term use, for example, reversal development (negative / positive development), Furthermore, by providing a protective layer comprising a cured resin obtained by curing at least a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure, a crack or a film is provided. Exfoliation does not occur, extremely high wear resistance is achieved, wear resistance and electrical characteristics are compatible, and there is no decrease in sensitivity or increase in residual potential even during repeated use over a long period of time. A highly durable and stable electrophotographic photosensitive member is provided.
That is, according to the electrophotographic photoreceptor of the present invention, it is possible to reduce the occurrence of background contamination during repeated use, to prevent residual potential, and to reduce the occurrence of dielectric breakdown during charging by a contact charging member or a charging member disposed in the vicinity. Electric characteristics and high durability are exhibited, and a stable image can be formed.
According to the image forming apparatus of the present invention, even when image formation (output) is repeatedly performed by reversal development (negative / positive development), abnormal images such as background contamination and density reduction are not generated, and the operation is highly durable and reliable. High-quality images can be output stably at any time. In particular, according to the tandem image forming apparatus of the present invention, a full-color and high-definition image can be output, and the time-dependent change (deterioration) of the photoconductor is small, so that a stable image can be formed even after repeated use. it can.
According to the process cartridge for an image forming apparatus of the present invention, highly durable and highly stable image output is possible, and handling is good and maintenance is improved.

As described above, the electrophotographic photosensitive member in the present invention is an electrophotographic photosensitive member in which at least a photosensitive layer and a protective layer are sequentially laminated on a conductive support.
The photosensitive layer has a maximum diffraction peak at 26.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray of CuKα (wavelength 1.542 mm), and 9.3 °. Also peaks at 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1 ° and 28.3 °. Resin cured product comprising a titanyl phthalocyanine crystal and a protective layer obtained by curing at least a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure It is characterized by comprising.
First, the electrophotographic photoreceptor of the present invention will be described.

In the present invention, the titanyl phthalocyanine crystal contained in the photosensitive layer can be synthesized by a characteristic method. That is, it has a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα, and further 9.4 °, 9. It has major peaks at 6 ° and 24.0 ° and has a peak at 7.3 ° as the lowest diffraction peak, and the 7.3 ° peak and the 9.4 ° peak. It is obtained by using a titanyl phthalocyanine crystal (precursor) that does not have a peak in between and a peak at 26.3 ° as a raw material, and crystal transitions this (crystal conversion treatment). .
Hereinafter, a method for synthesizing a titanyl phthalocyanine crystal having a specific crystal type as a precursor will be described, and then a method for transferring it to the crystal type of the present invention will be described in order.

[1] Synthesis method of precursor (the titanyl phthalocyanine crystal having the maximum diffraction peak at 27.2 °):
As a method for synthesizing the titanyl phthalocyanine crystal, for example, a method using no titanium halide as a raw material as described in JP-A-6-293769 is preferably used. That is, the greatest advantage (merit) of this synthesis method is that the synthesized titanyl phthalocyanine crystal is free of halogenation. If a titanyl phthalocyanine crystal contains a halogenated titanyl phthalocyanine crystal as an impurity, the electrostatic characteristics of a photoreceptor using the crystal often have adverse effects such as a decrease in photosensitivity and a decrease in chargeability (Japan Hardcopy ' 89, p. 103 (1989)).
In the present invention, although not limited, halogenated free titanyl phthalocyanine crystal as described in JP-A-2001-19871 is regarded as a main object, and these materials are effectively used. The That is, in order to synthesize the halogenated-free titanyl phthalocyanine, a halogenated material is not used as a raw material in the synthesis of titanyl phthalocyanine. Specifically, the following method is used.

First, a method for synthesizing a titanyl phthalocyanine crystal having the specific crystal type will be described.
[Synthetic method of synthetic crude product of titanyl phthalocyanine crystal]
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, for example, in JP-A-6-293769, “Phthalocyanine Compounds” (1963), “The Phthalineines” (1983), etc. by Moser et al. . Examples are given below.
The first method is a method in which a mixture of phthalic anhydrides, metals or metal halides 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.
The second method is a method in which phthalonitriles and metal halides are heated in the presence or absence of a high-boiling 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 in a metal halide and a high boiling point solvent. This is a reaction method.
The fourth method is a method in which phthalonitriles and a metal alkoxide are reacted in the presence of urea or the like.
Among the above methods, the fourth method does not cause chlorination (halogenation) to the benzene ring, and is an extremely useful method as a method for synthesizing an electrophotographic material, and is used extremely effectively in the present invention. The

[Preparation of amorphous titanyl phthalocyanine]
Next, a method for preparing amorphous titanyl phthalocyanine (hereinafter sometimes referred to as 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 an acid paste method or an acid slurry method can be used.

  As a specific method, the above-mentioned synthetic crude product of titanyl phthalocyanine crystal is dissolved in 10 to 50 times the amount of concentrated sulfuric acid, and if necessary, insoluble matter is removed by filtration or the like, and this is 10 to 50 times the amount of sulfuric acid. The solution is slowly poured into sufficiently cooled 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 content concentration of about 5 to 15% by mass.

  At this time, it is important to thoroughly wash the precipitated titanyl phthalocyanine 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 remaining amount of sulfuric acid is expressed quantitatively, it can be expressed by 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 μS / cm or less, more preferably 5 μS / cm or less, and particularly preferably 3 μS / cm or less. If the specific conductivity is 8 μS / cm or less, it can be determined that the residual 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-exchanged water after being 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 may be lowered or the photosensitivity may be deteriorated.

  What was produced as described above is the amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) used in the present invention. In this case, the amorphous titanyl phthalocyanine exhibits a maximum diffraction peak at 7.0 to 7.5 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα. It is preferable to have it. In particular, the half width of the diffraction peak is more preferably 1 ° or more. Furthermore, it is preferable that the average particle diameter of the primary particles is 0.1 μm or less.

Next, a method for crystal conversion of amorphous titanyl phthalocyanine will be described.
Crystal transformation is performed by using the amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) as a diffraction peak (± 0.2 °) at a Bragg angle 2θ with respect to the characteristic X-ray of CuKα (wavelength 1.542Å) at least 27.2 °. And has a major peak at 9.4 °, 9.6 °, and 24.0 °, and a peak at 7.3 ° as the lowest diffraction peak, And a step of converting to a titanyl phthalocyanine crystal (precursor) having no peak between the 7.3 ° peak and the 9.4 ° peak and having no peak at 26.3 °. .
As the specific method, the amorphous form of titanyl phthalocyanine is obtained by mixing and stirring together with an organic solvent in the presence of water without drying.

  At this time, any organic solvent can be used as long as the desired crystal form can be obtained. In particular, tetrahydrofuran, toluene, methylene chloride, carbon disulfide, orthodichlorobenzene, 1,1, Good results are obtained when one selected from 2-trichloroethane is selected. These organic solvents are preferably used alone, but two or more of these organic solvents may be mixed or used in combination with other solvents. The amount of the organic solvent used for crystal conversion is 10 times or more, preferably 30 times or more the mass of amorphous titanyl phthalocyanine (hereinafter sometimes referred to as amorphous or low crystalline titanyl phthalocyanine). Preferably there is.

This is because crystal conversion is caused quickly and sufficiently, and an effect of sufficiently removing impurities contained in the amorphous or low crystalline titanyl phthalocyanine is exhibited. The amorphous or low crystalline titanyl phthalocyanine used here is prepared by the acid paste method, but it is preferable to use one obtained by sufficiently washing sulfuric acid as described above.
When crystal conversion is performed under conditions where sulfuric acid remains, sulfate ions remain in the crystal particles, and the completed crystals cannot be completely removed even by an operation such as washing with water.

  When sulfate ions remain, preferable results cannot be obtained, such as a decrease in sensitivity and a decrease in chargeability of the photoreceptor. For example, Japanese Patent Application Laid-Open No. 8-110649 discloses a method for crystal conversion by adding 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, but the sulfate ion concentration in titanyl phthalocyanine is high and the light attenuation characteristic (photosensitivity) is poor. However, the method for producing titanyl phthalocyanine of the present invention is not good.

[2] Method for synthesizing titanyl phthalocyanine crystal used in the present invention:
The titanyl phthalocyanine crystal of the present invention is synthesized by crystal transition of the specific crystal type titanyl phthalocyanine crystal (precursor) synthesized as described above by an appropriate method.
As described above, the titanyl phthalocyanine crystal of the present invention is at least 26.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα. It has a maximum diffraction peak and is 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27. It has peaks at 1 ° and 28.3 °.

Next, a method for crystal transition of the precursor will be described. The precursor can undergo a crystal transition by applying thermal, mechanical and chemical energy.
Examples of the method for imparting thermal energy include a method in which the precursor is heat-treated at a high temperature of 100 ° C. or higher. For example, the precursor powder can be transferred to a desired crystal form by heat treatment at a high temperature of 200 ° C. or higher for several hours by a heating means such as an electric furnace. At this time, if the temperature is too high, a phenomenon occurs in which the titanyl phthalocyanine crystal itself decomposes, so that the upper limit of the heating temperature is about 400 ° C. The heat treatment is preferably performed in a dark place, and the heat treatment is performed in a light-shielded state. Furthermore, the heat treatment may be performed in the atmosphere, but may be performed under reduced pressure (for example, 10 mmHg or less).

  As a method for imparting mechanical energy, a method in which a mechanical shearing force is applied to the precursor is desirable. For example, a method of applying a shearing force with a mixer or the like, a method of applying a shearing force with a dry ball mill, a method of applying a shearing force with a mortar or the like can be used.

Chemical energy application methods can be broadly classified into two. One is based on a dry method, in which the crystal form is transferred by a method such as a vacuum deposition method. In this case, the precursor once falls to the molecular state and becomes a desired crystal form on the counter substrate.
The other is a wet method, in which the precursor is treated with an organic solvent. Specifically, the precursor is immersed in an organic solvent and left for a period of 1 day or longer. As a result, the crystal transitions to a desired crystal form.
In this case, any organic solvent can be used as long as it can crystallize the precursor into a desired crystal form, but one selected from ether solvents and ketone solvents can be used effectively. As the ether solvent, a branched or straight chain ether having 1 to 5 carbon atoms and a cyclic ether are effectively used, and tetrahydrofuran is particularly preferably used among them. As the ketone solvent, a branched or linear ketone having 1 to 5 carbon atoms is used, and 2-butanone is particularly preferably used.
In addition, it is important that the organic solvent to be used contains as little water and other components as possible. If the organic solvent contains a large amount of water, the rate of crystal transition decreases, which is not preferable.

  In the solvent treatment by the wet method, the crystal transition can be performed more efficiently by using mechanical energy together. For example, the crystal transition to a desired crystal type can be accelerated by putting the precursor together with the organic solvent into a milling device or the like (for example, a ball mill device) and applying a mechanical shearing force for a predetermined time.

Hereinafter, the electrophotographic photosensitive member of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing a configuration example of an electrophotographic photosensitive member used in the present invention, and the at least specific crystal form is placed on a conductive support 31 (hereinafter sometimes abbreviated as a support). A photosensitive layer 34 containing titanyl phthalocyanine crystals, a tri- or higher functional radical polymerizable monomer having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure on the photosensitive layer; The protective layer 39 made of cured resin is laminated.

  FIG. 2 is a cross-sectional view showing another structural example of the electrophotographic photosensitive member used in the present invention. On the support 31, a charge generation layer 37 containing at least a titanyl phthalocyanine crystal having a specific crystal type, A charge transporting layer having a charge transporting substance as a main component, and a trifunctional or higher-functional radical polymerizable monomer having no charge transporting structure and a monofunctional radical having a charge transporting structure on the charge transporting layer; The protective layer 39 made of a cured resin obtained by curing a polymerizable compound is laminated.

  FIG. 3 is a cross-sectional view showing still another structural example of the electrophotographic photosensitive member used in the present invention, which contains an intermediate layer 32 and a titanyl phthalocyanine crystal having at least a specific crystal type on a support 31. A charge generation layer 37 and a charge transport layer 38 mainly composed of a charge transport material are laminated, and further a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a charge transport structure on the charge transport layer. The protective layer 39 made of a cured resin obtained by curing a monofunctional radically polymerizable compound having a structure is laminated.

  In FIG. 4, the intermediate layer in FIG. 3 is composed of a charge blocking layer 35 and a moire preventing layer 36, and a charge generation layer 37 containing a titanyl phthalocyanine crystal having at least a specific crystal type on the intermediate layer, and a charge transport material And a monofunctional radically polymerizable compound having a charge transporting structure and a trifunctional or higher functional radical polymerizable monomer having at least a charge transporting structure on the charge transporting layer. The protective layer 39 made of a cured resin obtained by curing is laminated.

As the conductive support, show a volume resistivity ¹⁰ 10 Ω · cm or less conductive, for example, aluminum, nickel, chromium, nichrome, copper, gold, silver, metals such as platinum, tin oxide, indium oxide, etc. The metal oxide is 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., and extruded or drawn. After pipe formation, pipes that have been surface-treated by cutting, superfinishing, polishing, or the like can be used. Endless nickel belts and endless stainless steel belts can also be used as the conductive support.

Of the above, a cylindrical support made of aluminum, which can be easily subjected to the anodic oxide film treatment, can be most preferably used. The aluminum mentioned here includes both pure aluminum and aluminum alloys. Specifically, JIS 1000, 3000, and 6000 series aluminum or aluminum alloy is most suitable.
The anodized film is obtained by anodizing various metals or various alloys in an electrolyte solution. Among them, a film called anodized aluminum or an aluminum alloy that has been anodized in an electrolyte solution is used in the present invention. Most suitable as a body. In particular, it is excellent in preventing point defects (black spots, background stains) that occur when used in reversal development (negative / positive development).

The anodizing treatment is performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid. Of these, treatment with a sulfuric acid bath is most suitable. For example, sulfuric acid concentration: 10 to 20%, bath temperature: 5 to 25 ° C., current density: 1 to 4 A / dm ² , electrolytic voltage: 5 to 30 V, treatment time: treatment in the range of about 5 to 60 minutes However, the present invention is not limited to this. Since the anodic oxide film produced in this way is porous and has high insulation, the surface is very unstable. For this reason, there is a change with time after fabrication, and the physical property value of the anodized film is likely to change. In order to avoid this, it is desirable to further seal the anodized film.
Examples of the sealing treatment include a method of immersing the anodized film in an aqueous solution containing nickel fluoride and nickel acetate, a method of immersing the anodized film in boiling water, and a method of treating with pressurized steam. Among these, the method of immersing in the aqueous solution containing nickel acetate is the most preferable. Subsequent to the sealing treatment, the anodic oxide film is washed. The main purpose of this is to remove excess metal salts and the like attached by the sealing treatment.

If the adhered metal salt, etc., remains excessively on the surface of the support (anodized film), it not only adversely affects the quality of the coating film formed on the surface, but generally a low resistance component remains. In addition, it may cause scumming. Cleaning may be performed with pure water only once, but usually, multistage cleaning is performed. At this time, it is preferable that the final cleaning liquid is as clean as possible (deionized). Moreover, it is desirable to perform physical rubbing cleaning with a contact member in one of the multi-step cleaning processes.
The film thickness of the anodized film formed as described above is desirably about 5-15 μm. If it is too thin, the effect of the barrier property as an anodic oxide film is not sufficient, and if it is thicker than this, the time constant as an electrode becomes too large, resulting in the generation of residual potential and the response of the photoreceptor. There is a case.

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-vinylcarbazole, 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 applying the conductive powder and the binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, toluene and the like.

  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 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) when the photoreceptor is charged from being injected into the photosensitive layer from the support. 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.
Examples of the charge blocking layer include an anodized film typified by an aluminum oxide layer, an inorganic insulating layer typified by SiO, and a layer formed of a glassy network of metal oxide (for example, JP-A-3-191361). A layer made of polyphosphazene (for example, described in JP-A-3-141363), a layer made of an aminosilane reaction product (for example, described in JP-A-3-101737), and the like. In addition, a layer made of an insulating binder resin, a layer made of a curable binder resin, and the like can be given.
Among them, 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 moiré preventing layer and a photosensitive layer thereon, when these are provided by a wet coating method, the charge blocking layer must be composed of a material or a structure that does not attack the coating film by these coating solvents. Is essential.

Examples of binder resins that can be used include thermoplastic resins such as polyamide, polyester, vinyl chloride-vinyl acetate copolymer, and thermosetting resins such as active hydrogen (—OH group, —NH ₂ group, —NH group, etc.). And a thermosetting resin obtained by thermally polymerizing a compound containing a plurality of hydrogen groups and a compound containing a plurality of isocyanate groups and / or a compound containing a plurality of epoxy groups.
In this case, the compound containing a plurality of active hydrogens includes, for example, active hydrogens such as polyvinyl butyral, phenoxy resin, phenol resin, polyamide, polyester, polyethylene glycol, polypropylene glycol, polybutylene glycol, and hydroxyethyl methacrylate groups. Acrylic resin to be used. 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 resins. Among these, polyamide is most preferably used from the viewpoint of film formability, environmental stability, solvent resistance, and the like.

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

The 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 temperature and low humidity due to repeated charging and exposure, and when the film thickness is too thin, the blocking effect is reduced.
In addition, the charge blocking layer may contain chemicals, solvents, additives, curing accelerators, etc. necessary for curing (crosslinking) as necessary, and blade coating, dip coating, spray coating, It is formed on the support by a coating method, a nozzle coating method or the like. After the coating, it is dried or cured by a curing process such as drying, heating, or light.

Next, the moire preventing layer will be described.
The anti-moire layer is a layer having a function of preventing the generation of a moire image due to light interference inside the photosensitive layer when writing with coherent light such as laser light. Basically, it has a function of causing light scattering of the writing light. In order to exhibit such a function, it is effective that the anti-moire layer has a material having a large refractive index. In general, it comprises an inorganic pigment and a binder resin, and the inorganic pigment is dispersed in the binder resin. In particular, white pigments are effectively used among inorganic pigments, and for example, titanium oxide, calcium fluoride, calcium oxide, silicon oxide, magnesium oxide, aluminum oxide, and the like are favorably used. Among these, titanium oxide having a large hiding power can be most effectively used.

  In addition, when a charge blocking layer is used, charge injection from the support is prevented by the charge blocking layer. Therefore, in the moire preventing layer, a charge having the same polarity as that of the charge charged on the surface of the photoreceptor. It is preferable from the viewpoint of preventing residual potential. For this reason, for example, in the case of a negatively charged type photoreceptor, it is desirable to impart electronic conductivity to the moire prevention layer, and the inorganic pigment to be used is one that has electron conductivity, or one that is conductive. It is desirable to do. Alternatively, the use of an electron conductive material (for example, an acceptor) or the like for the moire preventing layer makes the effect of the present invention more remarkable.

As the binder resin for the moire prevention layer, the same resin as the charge blocking layer can be used, but considering that the photosensitive layer is laminated on the moire prevention layer, it is important that it is not affected by the coating solvent of the photosensitive layer. is there.
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 the alkyd / melamine resin is an important factor that determines the structure and characteristics of the moire prevention layer. A range in which the ratio (weight ratio) of the two (alkyd / melamine) is 5/5 to 8/2 can be cited as a good mixing ratio range. When 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. If the alkyd resin is richer than 8/2, it is effective in reducing the residual potential of the photoconductor, but it is not desirable because the bulk resistance becomes too low and the soiling becomes worse.

  In the anti-moire layer, the volume ratio between the inorganic pigment and the binder resin determines an important characteristic. For this reason, it is important that the volume ratio of the inorganic pigment to the binder resin is in the range of 1/1 to 3/1. When the volume ratio of the two is less than 1/1, not only the moire prevention ability is lowered, but there is a case where the increase of the residual potential in repeated use becomes large. On the other hand, in the region where the volume ratio is 3/1 or more, not only the binding ability of the binder resin is inferior, but also the surface property of the coating film is deteriorated, which may adversely affect the film forming property of the upper photosensitive layer. This effect can be a serious problem when the photosensitive layer is a laminated type and a thin layer such as a charge generation layer is formed. In addition, when the volume ratio is 3/1 or more, there are cases where the binder resin cannot cover the surface of the inorganic pigment, and direct contact with the charge generation material increases the probability of heat carrier generation, resulting in soiling. It may have an adverse effect on it.

Furthermore, by using two types of titanium oxides having different average particle diameters for the moire prevention layer, it is possible to improve the concealing power to the conductive substrate and suppress moire and to cause a pin that causes an abnormal image. The hole can be eliminated. For this purpose, it is important that the ratio of the average particle diameters of the two types of titanium oxide to be used is within a certain range (0.2 ≦ D2 / D1 ≦ 0.5). Note that D2 <D1.
In the case of the particle size ratio outside the above range defined in the present invention, that is, the ratio of the average particle size of the other titanium oxide (T2) to the average particle size of one titanium oxide (T1) is too small (0.2> In the case of D2 / D1), the activity on the surface of titanium oxide is increased, and the electrostatic stability of the electrophotographic photosensitive member is significantly impaired. Further, when the ratio of the average particle diameter of the other titanium oxide (T2) to the average particle diameter of one titanium oxide (T1) is too large (D2 / D1> 0.5), the hiding power to the conductive substrate is lowered. In addition, the suppression of moiré and abnormal images is reduced. The average particle size mentioned here is obtained from a particle size distribution measurement obtained when strong dispersion is performed in an aqueous system.

  Further, the average particle size (D2) in the titanium oxide (T2) having a smaller particle size is an important factor, and it is important that 0.05 μm ≦ D2 ≦ 0.20 μm. When it is smaller than 0.05 μm, the hiding power is reduced, and moire may be generated. On the other hand, when it is larger than 0.20 μm, the filling rate of titanium oxide in the moire preventing layer is lowered, and the effect of suppressing soiling cannot be sufficiently exhibited.

  The mixing ratio (weight ratio) of the two types of titanium oxide is also an important factor. When T2 / (T1 + T2) is smaller than 0.2, the filling rate of titanium oxide is not so large and the effect of suppressing soiling cannot be sufficiently exhibited. On the other hand, when it is larger than 0.8, the concealing power is reduced, and moire may be generated. Therefore, it is important that 0.2 ≦ T2 / (T1 + T2) ≦ 0.8.

  The thickness of the moire preventing layer is 1 to 10 μm, preferably 2 to 5 μm. If the film thickness is less than 1 μm, the effect is small, and if it exceeds 10 μm, residual potential is accumulated, which is not desirable.

  The inorganic pigment is 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 drug, a solvent, an additive, a curing accelerator, etc. necessary for curing (crosslinking) as necessary. In addition, it 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 photosensitive layer will be described. As described above, the photosensitive layer is composed of a single photosensitive layer mainly composed of a charge generation material and a charge transport material, and a charge generation layer and a charge transport material mainly composed of a charge generation material. In some cases, the charge transport layer has a laminated structure. Here, for convenience of explanation, a case of a laminated structure will be described first.

The charge generation layer has a maximum diffraction peak at 26.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα as a charge generation material. 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1 °, 28.3 ° Further, it is a layer containing a titanyl phthalocyanine crystal having a peak as a main component.
In the charge generation layer, the above pigment (titanyl phthalocyanine crystal) is dispersed in a suitable solvent together with a binder resin (binder resin) if necessary using a ball mill, attritor, sand mill, ultrasonic wave, etc. It is formed by coating on a support and drying.

  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, cellulose 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 of the coating solution, methods such as dip coating, spray coating, beat coating, nozzle coating, spinner coating, ring coating, and 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 a charge transport material and a 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 chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2, 4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7- Examples thereof include electron-accepting substances such as trinitrodibenzothiophene-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. Known materials may be mentioned. These charge transport materials may be used alone or in combination of two or more.

  As the binder resin for the charge transport layer, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer , Polyvinyl acetate, polyvinylidene 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 And thermoplastic or thermosetting resins such as urethane resin, phenol resin, and alkyd resin.

The amount of the charge transport material is appropriately 20 to 300 parts by weight, preferably 40 to 150 parts by weight with respect to 100 parts by weight of the binder resin. The thickness of the charge transport layer is preferably about 5 to 100 μm.
As a suitable solvent for dissolving or dispersing the charge transport material and the binder resin, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are 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 such a 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 following general formulas (I) to (X) are preferably used, and these are exemplified below and specific examples are shown.

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

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

(In the formula (b), a is an integer of 1 to 20, b is an integer of 1 to 2000, R ₁₀₃ and R ₁₀₄ represent a substituted or unsubstituted alkyl group or aryl group.) Here, R ₁₀₁ and R ₁₀₂ , R ₁₀₃ and R ₁₀₄ may be the same or different. The divalent group represented by this is represented. ]

[In Formula (II), R ₇ and R ₈ represent a substituted or unsubstituted aryl group, and Ar ₁ , Ar ₂ , and Ar ₃ represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I). ]

Wherein _{(III), R 9, R} 10 is a substituted or unsubstituted aryl _{group, Ar 4, Ar 5, Ar} 6 independently represent an arylene group. X, k, j, and n are the same as in the formula (I). ]

[In formula (IV), R ₁₁ and R ₁₂ represent a substituted or unsubstituted aryl group, and Ar ₇ , Ar ₈ and Ar ₉ represent the same or different arylene groups. X, k, j, and n are the same as in the formula (I). ]

[In the formula (V), R ₁₃ and R ₁₄ are substituted or unsubstituted aryl groups, Ar ₁₀ , Ar ₁₁ and Ar ₁₂ are the same or different arylene groups, X ₁ and X ₂ are substituted or unsubstituted ethylene groups, Or a substituted or unsubstituted vinylene group. X, k, j, and n are the same as in the formula (I). ]

[In the formula (VI), 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 represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group, which may be the same or different. Also good. X, k, j, and n are the same as in the formula (I). ]

[In Formula (VII), R ₁₉ and R ₂₀ represent a hydrogen atom or a substituted or unsubstituted aryl group, and R ₁₉ and R ₂₀ may form a ring. Ar ₁₇ , Ar ₁₈ and Ar ₁₉ represent the same or different arylene groups. X, k, j, and n are the same as in the formula (I). ]

[In formula (VIII), R ₂₁ represents a substituted or unsubstituted aryl group, Ar ₂₀ , Ar ₂₁ , Ar ₂₂ , Ar ₂₃ represent the same or different arylene groups. X, k, j, and n are the same as in the formula (I). ]

[In the formula (IX), R ₂₂ , R ₂₃ , R ₂₄ and R ₂₅ represent a substituted or unsubstituted aryl group, and Ar ₂₄ , Ar ₂₅ , Ar ₂₆ , Ar ₂₇ and Ar ₂₈ represent the same or different arylene groups. X, k, j, and n are the same as in the formula (I). ]

[In formula (X), R ₂₆ and R ₂₇ represent a substituted or unsubstituted aryl group, Ar ₂₉ , Ar ₃₀ and Ar ₃₁ represent the same or different arylene groups. X, k, j, and n are the same as in the formula (I). ]

  In addition to the polymer charge transport material described above, the polymer charge transport material used for the charge transport layer may be formed in the state of a monomer or oligomer having an electron donating group when forming the charge transport layer. A polymer having a two-dimensional or three-dimensional crosslinked structure is finally included by performing a curing reaction or a crosslinking reaction later.

  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 the other polymer having an electron donating group include a copolymer of a known monomer, a block polymer, a graft polymer, a star polymer, for example, JP-A-3-109406, JP-A-2000-206723. It is also possible to use a cross-linked polymer having an electron donating group as disclosed in JP-A No. 2001-340001 and the like. Also in this case, a material that can satisfy the above mobility can be used effectively.

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, and polymers or oligomers having a perfluoroalkyl group in the side chain are used, and the amount used is 0 to 1 with respect to the binder resin. Weight percent is appropriate.

Next, the case of a single photosensitive layer will be described.
As the binder resin, the binder resin previously mentioned in the charge transport layer may be used as it is, or the binder resin mentioned in the charge generation layer may be mixed and used. Of course, the polymer charge transport materials mentioned above can also be used favorably. The amount of the charge generating material with respect to 100 parts by weight of the binder resin is preferably 5 to 40 parts by weight, and the amount of the charge transporting material is preferably 0 to 190 parts by weight, more preferably 50 to 150 parts by weight.
The single-layer photosensitive layer is immersed in a coating solution in which a charge generating material and a binder resin are dispersed with a disperser using a solvent such as tetrahydrofuran, dioxane, dichloroethane, and cyclohexane together with a charge transport material if necessary. It can be formed by coating using a coating method, spray coating, bead coating, or the like. The thickness of the single photosensitive layer is suitably about 5 to 100 μm.

Next, the protective layer will be described.
In the electrophotographic photoreceptor of the present invention, a protective layer is 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 it has been desired to reduce the size of the apparatus together with high-speed output by a printer. That is, a high-sensitivity photosensitive member free from abnormal defects, which is provided with a protective layer having the structure of the present invention and has improved durability, can be usefully used to meet the above-mentioned demand.

The effective protective layer used in the present invention is formed by curing at least a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure. The composition (resin cured product). Hereinafter, the “protective layer” may be referred to as a “crosslinked protective layer”. Further, “radical polymerizable monomer” and “radical polymerizable compound” may be referred to as “reactive monomer” or simply “monomer”.
Regarding the formation of a cross-linked structure, a reactive monomer having a plurality of cross-linkable functional groups in one molecule is used to cause a cross-linking reaction using light or thermal energy to form a three-dimensional network structure. is there. This network structure functions as a binder resin and exhibits high wear resistance.

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

  The protective layer having a network structure as described above has high wear resistance, but has a large volume shrinkage during the crosslinking reaction, and may cause cracks if it is too thick. In such a case, the protective layer may be a laminated structure, a low molecular dispersion polymer protective layer may be used for the lower layer (photosensitive layer side), and a protective layer having a crosslinked structure may be formed on the upper layer (surface side). Good. Among the cross-linked protective layers, the protective layer having a specific configuration in the present invention is particularly effectively used.

The specific crosslinkable protective layer is, as described above, a resin obtained by curing at least a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure. It is a protective layer made of a cured product.
Since the protective layer in the present invention has a crosslinked structure obtained by curing a tri- or higher functional radically polymerizable monomer, a three-dimensional network structure is developed, the crosslinking density is very high, and it has high hardness and high elasticity. It is a surface layer, is uniform and has high smoothness, and achieves high wear resistance and scratch resistance. As described above, on the surface of the photoreceptor, it is important to increase the crosslink density, that is, the number of crosslink bonds per unit volume. When a large number of bonds are formed, internal stress due to volume shrinkage occurs.
This internal stress increases as the thickness of the cross-linking protective layer increases, and cracks and film peeling tend to occur when the entire protective layer is cured in a thick film state. Even if this phenomenon does not appear in the initial state, it is repeatedly used in the electrophotographic process, and may easily occur over time due to the effects of charging, development, transfer, cleaning hazards, and thermal fluctuations.

  As a method for solving this problem, (1) a polymer component is introduced into the crosslinked layer and the crosslinked structure, (2) a large amount of monofunctional and bifunctional radically polymerizable monomers are used, and (3) a flexible group is introduced. Although the method of softening the cured resin layer using the polyfunctional monomer which has is mentioned, the bridge | crosslinking density of a bridge | crosslinking layer becomes thin in any case, and remarkable abrasion resistance is not achieved.

  On the other hand, in the photoreceptor of the present invention, a cross-linking protective layer having a high cross-linking density in which a three-dimensional network structure is developed on the charge transport layer is preferably provided with a thickness of 1 μm or more and 10 μm or less. No cracks or film peeling occur, and very high wear resistance is achieved. By making the film thickness of the crosslinkable protective layer 2 μm or more and 8 μm or less, in addition to further improving the margin for the above problem, it is possible to select a material for increasing the crosslink density that leads to further improvement in wear resistance. It becomes possible.

The reason why the photoconductor of the present invention can suppress cracks and film peeling is that the crosslinkable protective layer can be made thin, so that the internal stress does not increase, and since the lower layer has a photosensitive layer or charge transport layer, the surface crosslinkable protection This is because the internal stress of the layer can be relaxed. For this reason, it is not necessary to contain a large amount of polymer material in the crosslinkable protective layer, and the polymer material and radical polymerizable composition (radical polymerizable monomer or radical polymerizable compound having a charge transporting structure) generated at this time. Scratches and toner filming due to incompatibility with the cured product resulting from this reaction are unlikely to occur.
Furthermore, when the thick film over the entire protective layer is cured by light energy irradiation, light absorption by the charge transporting structure is limited, and a phenomenon in which the curing reaction does not proceed sufficiently may occur.
In the crosslinkable protective layer of the present invention, preferably a thin film having a thickness of 10 μm or less causes a uniform curing reaction to proceed to the inside, and high wear resistance is maintained inside the protective layer as well as the surface of the protective layer.

  In addition, in the formation of the crosslinkable protective layer of the present invention, in addition to the above-described trifunctional or higher functional radical polymerizable monomer (trifunctional radical polymerizable monomer) having no charge transport structure, it further has a charge transport structure. It contains a monofunctional radically polymerizable compound (a radically polymerizable compound having a monofunctional charge transporting structure), and this is incorporated into the cross-linking during curing of the above-described trifunctional or higher functional radical polymerizable monomer. On the other hand, when a low molecular charge transport material having no functional group is contained in the cross-linked surface layer, precipitation of the low molecular charge transport material and white turbidity occur due to its low compatibility, and the cross-linked surface layer The mechanical strength also decreases. On the other hand, when a bifunctional or higher-functional charge transporting compound is used as the main component, the crosslink structure is fixed by a plurality of bonds and the crosslink density is further increased. Becomes very large, which increases the internal stress of the crosslinked protective layer.

Furthermore, the photoreceptor of the present invention has good electrical characteristics, and therefore has excellent repeated stability, realizing high durability and high stability. This is because a radical polymerizable compound having a monofunctional charge transporting structure is used as a constituent material of the crosslinkable protective layer and is immobilized in a pendant shape between the crosslinks. As described above, the charge transport material having no functional group causes precipitation and clouding phenomenon, and the electrical characteristics are remarkably deteriorated in repeated use such as a decrease in sensitivity and an increase in residual potential.
When a bifunctional or higher-functional charge transporting compound is used as the main component, it is fixed in the crosslinked structure with a plurality of bonds, so the intermediate structure (cation radical) during charge transport cannot be kept stable, Sensitivity decreases due to traps and residual potential increases. Such deterioration of the electric characteristics appears as an image such as a decrease in image density and thinning of characters. Further, in the photoreceptor of the present invention, the high charge mobility design with less charge trapping of the conventional photoreceptor can be applied as the lower charge transport layer, and the electrical side effects of the crosslinked protective layer can be minimized. .

Furthermore, in the formation of the above-mentioned crosslinkable protective layer of the present invention, the drastic wear resistance is exhibited particularly by making the crosslinkable protective layer insoluble in the organic solvent. The crosslinked protective layer of the present invention is formed by curing a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure. Dimensional network structure develops and has a high crosslinking density, but contains other than the above components (for example, mono- or bifunctional monomers, polymer binders, antioxidants, leveling agents, plasticizers and other additives and lower layers) In some cases, the cross-linking density is locally dilute or the aggregate is formed of fine cured products cross-linked with high density.
Such a crosslinkable protective layer has low bonding strength between cured products and is soluble in organic solvents, and is repeatedly used in the electrophotographic process. Detachment easily occurs. By making the cross-linkable protective layer insoluble in an organic solvent as in the present invention, the original three-dimensional network structure is developed and has a high degree of cross-linking, and the chain reaction proceeds in a wide range so that a cured product is obtained. Due to the high molecular weight, a dramatic improvement in wear resistance is achieved.

Next, the constituent material of the crosslinking type protective layer coating solution of the present invention will be described.
Examples of the trifunctional or higher functional radical polymerizable monomer having no charge transport structure used in the present invention include hole transport structures such as triarylamine, hydrazone, pyrazoline, carbazole, such as condensed polycyclic quinone, diphenoquinone, A monomer having no electron transport structure such as an electron-withdrawing aromatic ring having a cyano group or a nitro group and having three or more radical polymerizable functional groups. The radical polymerizable functional group may be any group as long as it has a carbon-carbon double bond and is capable of radical polymerization. Examples of these radical polymerizable functional groups include 1-substituted ethylene functional groups and 1,1-substituted ethylene functional groups shown below.

(1) As 1-substituted ethylene functional group, the functional group represented by following General formula (7) is mentioned, for example.

[In the general formula (7), X ₁ represents an arylene group such as a phenylene group optionally having a substituent, a naphthylene group, an alkenylene group optionally having a substituent, a —CO— group, —COO— group, —CON (R ₁₀ ) — group [wherein R ₁₀ is an alkyl group such as hydrogen, methyl group or ethyl group, aralkyl group such as benzyl group, naphthylmethyl group or phenethyl group, phenyl group, naphthyl group, etc. Represents an aryl group. Or -S- group. ]

  Specific examples of the functional group include a vinyl group, a styryl group, a 2-methyl-1,3-butadienyl group, a vinylcarbonyl group, an acryloyloxy group, an acryloylamide group, and a vinyl thioether group.

(2) Examples of the 1,1-substituted ethylene functional group include functional groups represented by the following general formula (8).

[In the general formula (8), Y represents an alkyl group which may have a substituent, an aralkyl group which may have a substituent, a phenyl group which may have a substituent, naphthyl. An aryl group such as a group, an alkoxy group such as a halogen atom, a cyano group, a nitro group, a methoxy group or an ethoxy group, a —COOR ₁₁ group [R ₁₁ is a hydrogen atom, an optionally substituted methyl group, ethyl An alkyl group such as a group, an aralkyl group such as an optionally substituted benzyl or phenethyl group, an aryl group such as an optionally substituted phenyl group or naphthyl group, or —CONR ₁₂ R ₁₃ ( R ₁₂ and R ₁₃ are each a hydrogen atom, an optionally substituted alkyl group such as a methyl group or an ethyl group, an optionally substituted benzyl group, a naphthylmethyl group, or a phenethyl group. Aralkyl group Or a substituent a phenyl group which may have a represents an aryl group such as a naphthyl group, a mutually identical or may be different.). X ₂ represents the same substituent, single bond, and alkylene group as X _{1 in the} general formula (7). However, at least one of Y and X ₂ is an oxycarbonyl group, a cyano group, an alkenylene group, or an aromatic ring. ]

Specific examples of the functional group include an α-acryloyloxy group, a methacryloyloxy group, an α-cyanoethylene group, an α-cyanoacryloyloxy group, an α-cyanophenylene group, and a methacryloylamino group.
Examples of the substituent further substituted on the substituents for X ₁ , X ₂ and Y include, for example, a halogen atom, a nitro group, a cyano group, a methyl group, an alkyl group such as an ethyl group, a methoxy group, and an ethoxy group. And aryloxy groups such as phenoxy group, aryl groups such as phenyl group and naphthyl group, and aralkyl groups such as benzyl group and phenethyl group.

  Among these radical polymerizable functional groups, an acryloyloxy group and a methacryloyloxy group are particularly useful, and a compound having three or more acryloyloxy groups includes, for example, a compound having three or more hydroxyl groups in the molecule. It can be obtained by an ester reaction or a transesterification reaction using acrylic acid (salt), acrylic acid halide, and acrylic ester. A compound having three or more methacryloyloxy groups can be obtained in the same manner. Further, the radical polymerizable functional groups in the monomer having three or more radical polymerizable functional groups may be the same or different.

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

  Further, the trifunctional or higher functional radical polymerizable monomer having no charge transport structure used in the present invention has a molecular weight relative to the number of functional groups in the monomer in order to form a dense crosslink in the crosslinkable protective layer. The ratio (molecular weight / functional group number) is preferably 250 or less. On the other hand, if this ratio is larger than 250, the crosslinked protective layer tends to be soft and wear resistance tends to decrease somewhat. Therefore, among the monomers exemplified above, monomers having modifying groups such as EO, PO, caprolactone, etc. In this case, it is not preferable to use a compound having an extremely long modifying group alone.

  In addition, the proportion of the trifunctional or higher functional radical polymerizable monomer having no charge transporting structure used in the crosslinkable protective layer is 20 to 80% by weight, preferably 30 to 70% by weight, based on the total amount of the crosslinkable protective layer. is there. When the monomer component is less than 20% by weight, the three-dimensional crosslink density of the crosslinkable protective layer is small, and it is difficult to achieve a dramatic improvement in wear resistance as compared with the case of using a conventional thermoplastic binder resin. On the other hand, when it exceeds 80% by weight, the content of the charge transporting compound is lowered, and the electrical characteristics tend to deteriorate. The electrical characteristics and abrasion resistance required vary depending on the process used, and the thickness of the cross-linked protective layer of the photoconductor also varies accordingly. A weight percent range is most preferred.

  Examples of the monofunctional radically polymerizable compound having a charge transporting structure (radical polymerizable compound having a monofunctional charge transporting structure) used in the crosslinked protective layer of the present invention include, for example, triarylamine, hydrazone, and pyrazoline. Has a hole transporting structure such as carbazole, for example, an electron transporting structure such as condensed polycyclic quinone, diphenoquinone, an electron-withdrawing aromatic ring having a cyano group or a nitro group, and one radical polymerizable It refers to a compound having a functional group. Examples of the radical polymerizable functional group include those shown in the above radical polymerizable monomer, and acryloyloxy group and methacryloyloxy group are particularly useful. In addition, a triarylamine structure has a high effect as a charge transporting structure, and in particular, when a compound represented by the structure of the following general formula (1) or (2) is used, electrical characteristics such as sensitivity and residual potential Is well maintained.

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

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

Ar ₃ and Ar ₄ represent a substituted or unsubstituted aryl group. In the present invention, the aryl group includes a condensed polycyclic hydrocarbon group, a non-condensed cyclic hydrocarbon group, and a heterocyclic group. The following groups are mentioned.

  The condensed polycyclic hydrocarbon group preferably has 18 or less carbon atoms forming a ring, for example, a pentanyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptaenyl group, a biphenylenyl group, an as-indacenyl group. , S-indacenyl group, fluorenyl group, acenaphthylenyl group, preadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrenyl group, aceanthrylenyl group, triphenylyl group, pyrenyl group , A chrycenyl group, a naphthacenyl group, and the like.

Examples of the non-fused cyclic hydrocarbon group include monovalent groups of monocyclic hydrocarbon compounds such as benzene, diphenyl ether, polyethylene diphenyl ether, diphenyl thioether, and diphenyl sulfone, or biphenyl, polyphenyl, diphenylalkane, diphenylalkene, diphenylalkyne. , Monovalent groups of non-condensed polycyclic hydrocarbon compounds such as triphenylmethane, distyrylbenzene, 1,1-diphenylcycloalkane, polyphenylalkane, and polyphenylalkene, or rings such as 9,9-diphenylfluorene Examples thereof include monovalent groups of aggregated hydrocarbon compounds.
Examples of the heterocyclic group include monovalent groups such as carbazole, dibenzofuran, dibenzothiophene, oxadiazole, and thiadiazole.

The aryl group represented by Ar ₃ or Ar ₄ may have a substituent as shown below, for example.
[1] Halogen atom, cyano group, nitro group and the like.
[2] Alkyl groups, preferably C ₁ -C _12, especially C ₁ -C ₈ , more preferably C ₁ -C ₄ linear or branched alkyl groups, and these alkyl groups further contain fluorine atoms , a hydroxyl group, a cyano group, an alkoxy group of C ₁ -C _4, a phenyl group or a halogen atom, which may have a phenyl group substituted by an alkoxy group C ₁ -C ₄ alkyl or C ₁ -C ₄ Good. Specifically, methyl group, ethyl group, n-butyl group, i-propyl group, t-butyl group, s-butyl group, n-propyl group, trifluoromethyl group, 2-hydroxyethyl group, 2-ethoxy Examples include ethyl group, 2-cyanoethyl group, 2-methoxyethyl group, benzyl group, 4-chlorobenzyl group, 4-methylbenzyl group, 4-phenylbenzyl group and the like.
[3] An alkoxy group (—OR ₂ ), and R ₂ represents the alkyl group defined in [2]. Specifically, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, t-butoxy group, n-butoxy group, s-butoxy group, i-butoxy group, 2-hydroxyethoxy group, benzyloxy group And a trifluoromethoxy group.
[4] An aryloxy group, and examples of the aryl group include a phenyl group and a naphthyl group. It may contain an alkoxy group having C ₁ -C _4, alkyl group, or a halogen atom C ₁ -C ₄ as a substituent. Specific examples include a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a 4-methoxyphenoxy group, and a 4-methylphenoxy group.
[5] Alkyl mercapto group or aryl mercapto group, and specific examples include methylthio group, ethylthio group, phenylthio group, p-methylphenylthio group and the like.
[6] The following general formula (9):

[In General Formula (9), R ₃ and R ₄ each independently represent a hydrogen atom, an alkyl group defined in the above [2], or an aryl group. Examples of the aryl group include a phenyl group, and a biphenyl group or a naphthyl group, which may contain an alkoxy group of C ₁ -C _4, alkyl group, or a halogen atom C ₁ -C ₄ as a substituent . R ₃ and R ₄ may form a ring together. ] Is represented.
Specifically, amino group, diethylamino group, N-methyl-N-phenylamino group, N, N-diphenylamino group, N, N-di (tolyl) amino group, dibenzylamino group, piperidino group, morpholino group And pyrrolidino group.

[7] Methylenedioxy group, alkylenedioxy group such as methylenedithio group, or alkylenedithio group.
[8] Substituted or unsubstituted styryl group, substituted or unsubstituted β-phenylstyryl group, diphenylaminophenyl group, ditolylaminophenyl group and the like.

The arylene group represented by Ar ₁ or Ar ₂ is a divalent group derived from the aryl group represented by Ar ₃ or Ar ₄ .

  X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group.

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

Examples of the substituted or unsubstituted cycloalkylene group, a cyclic alkylene group of C ₅ -C _7, a fluorine atom in these cyclic alkylene group, a hydroxyl group, an alkyl group of _{C 1 ~C 4, C 1 ~C} 4 It may have an alkoxy group.
Specific examples include a cyclohexylidene group, a cyclohexylene group, and a 3,3-dimethylcyclohexylidene group.

  The substituted or unsubstituted alkylene ether group represents ethyleneoxy, propyleneoxy, ethylene glycol, propylene glycol, diethylene glycol, tetraethylene glycol, tripropylene glycol, and the alkylene ether group alkylene group is a hydroxyl group, a methyl group, an ethyl group. And the like.

  As the vinylene group, the following general formula (10) or (11):

[In General Formula (10) or (11), R ₅ is hydrogen, an alkyl group (the same as the alkyl group defined in [2] above), an aryl group (the aryl group represented by Ar ₃ or Ar ₄ above) The same), a represents 1 or 2, and b represents 1-3. ] Is represented.

Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, or an alkyleneoxycarbonyl divalent group.
Examples of the substituted or unsubstituted alkylene group include the same alkylene groups as those described above for X.
Examples of the substituted or unsubstituted alkylene ether divalent group include the alkylene ether divalent group of X.
Examples of the alkyleneoxycarbonyl divalent group include a caprolactone divalent modifying group.

  Further, as a monofunctional radically polymerizable compound having a charge transporting structure (radical polymerizable compound having a monofunctional charge transporting structure), a compound having a structure represented by the following general formula (3) is preferable. It is done.

  [In general formula (3), o, p and q are each an integer of 0 or 1, Ra represents a hydrogen atom or a methyl group, Rb and Rc are substituents other than a hydrogen atom, and an alkyl group having 1 to 6 carbon atoms. And a plurality of cases may be different. s and t represent an integer of 0 to 3. Za represents a single bond, a methylene group, an ethylene group, or a divalent group represented by the following structural formulas (4), (5), and (6). ]

  As the compound represented by the general formula (3), compounds having a methyl group or an ethyl group are particularly preferable as substituents for Rb and Rc.

The radical polymerizable compound having a monofunctional charge transporting structure represented by the above general formulas (1) and (2), particularly (3) used in the present invention is polymerized by releasing the carbon-carbon double bond on both sides. Therefore, it does not become a terminal structure, but is incorporated in a chain polymer and crosslinked by polymerization with a tri- or higher functional radical polymerizable monomer, that is, in a cured resin, in a polymer main chain. And present in a cross-linked chain between the main chain and the main chain (in this cross-linked chain, an intermolecular cross-linked chain between one polymer and another polymer and a folded state in one polymer) There is an intramolecular cross-linked chain in which a part of the main chain of the polymer and another part derived from the polymerized monomer are cross-linked at a position away from the main chain).
As described above, even when the radically polymerizable compound having a monofunctional charge transport structure is present in the main chain or in the cross-linked chain, the main chain or the cross-linked chain moiety is present. The triarylamine structure suspended from the chain has at least three aryl groups arranged radially from the nitrogen atom and is bulky, but is not directly bonded to the main chain or bridging chain part, but from the chain part to the carbonyl group. The triarylamine structures can be arranged adjacent to each other in the polymer moderately because they are fixed in a state that is flexible in three-dimensional positioning. For this reason, it is presumed that an intramolecular structure that is relatively free from the interruption of the charge transport path can be taken when it is used as a surface layer of an electrophotographic photoreceptor with little structural distortion in the molecule.
Specific examples of the radical polymerizable compound having a monofunctional charge transporting structure of the present invention are as follows. 1-No. 161, it is not limited to compounds having these structures.

  Further, the radical polymerizable compound having a monofunctional charge transporting structure used in the present invention is important for imparting the charge transporting performance of the crosslinkable protective layer, and this component is 20 to 80 with respect to the crosslinkable protective layer. % By weight, preferably 30 to 70% by weight. If this component is less than 20% by weight, the charge transport performance of the cross-linked protective layer cannot be sufficiently maintained, and repeated use tends to cause deterioration of electrical characteristics such as a decrease in sensitivity and an increase in residual potential. On the other hand, if it exceeds 80% by weight, the content of the trifunctional monomer having no charge transporting structure is lowered, and the crosslink density is lowered, so that high wear resistance tends to be hardly exhibited. The electrical characteristics and abrasion resistance required vary depending on the process used, and accordingly the film thickness of the crosslinked protective layer of the photoreceptor in the present invention also differs. A range of ˜70% by weight is most preferred.

  The crosslinkable protective layer constituting the electrophotographic photosensitive member of the present invention is obtained by curing at least a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. However, in addition to this, monofunctional and bifunctional radically polymerizable monomers and functionalities for the purpose of imparting functions such as viscosity adjustment during coating, stress relaxation of the cross-linked protective layer, low surface energy, and reduction of friction coefficient, etc. A monomer and a radically polymerizable oligomer can be used in combination. Known radical polymerizable monomers and oligomers can be used.

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

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

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

  Examples of the radical polymerizable oligomer include epoxy acrylate, urethane acrylate, and polyester acrylate oligomers.

  However, when a large amount of monofunctional and bifunctional radically polymerizable monomers and radically polymerizable oligomers are contained, the three-dimensional crosslink density of the crosslinkable protective layer is substantially reduced, resulting in a decrease in wear resistance. Therefore, the content of these monomers and oligomers is more preferably 50 parts by weight or less, preferably 30 parts by weight or less, with respect to 100 parts by weight of the tri- or higher functional radical polymerizable monomer.

  Further, the crosslinkable protective layer of the present invention is made of a cured resin obtained by curing at least a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure. However, if necessary, a polymerization initiator may be contained in the crosslinked protective layer coating solution in order to allow the curing reaction to proceed efficiently.

  Examples of the thermal polymerization initiator include 2,5-dimethylhexane-2,5-dihydroperoxide, dicumyl peroxide, benzoyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di ( Peroxybenzoyl) hexyne-3, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, lauroyl peroxide, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) B) Peroxide-based initiators such as propane, azo-based compounds such as azobisisobutylnitrile, azobiscyclohexanecarbonitrile, methyl azobisisobutyrate, azobisisobutylamidine hydrochloride, 4,4′-azobis-4-cyanovaleric acid Initiators are mentioned.

  Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2- Acetophenone-based or ketal-based photopolymerization initiators such as methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, Benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether Benzoin ether photopolymerization initiators such as benzoin isopropyl ether, benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoylphenyl ether, acrylated benzophenone, Benzophenone photopolymerization initiators such as 1,4-benzoylbenzene, thioxanthones such as 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone Examples of photopolymerization initiators and other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoic acid. Phenylethoxyphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10 -Phenanthrenes, acridine compounds, triazine compounds, imidazole compounds, and the like.

  Moreover, what has a photopolymerization acceleration effect can also be used individually or in combination with the said photoinitiator. Examples include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, 4,4'-dimethylaminobenzophenone, and the like.

  These polymerization initiators may be used alone or in combination of two or more. The content of the polymerization initiator is 0.5 to 40 parts by weight, preferably 1 to 20 parts by weight with respect to 100 parts by weight of the total content having radical polymerizability.

  Furthermore, the coating liquid for forming a crosslinked protective layer of the present invention may contain various plasticizers (for the purpose of stress relaxation and adhesion improvement), leveling agents, and low molecular charge transport materials that do not have radical reactivity as necessary. An agent can be contained. As these additives, known additives can be used, and as plasticizers, those used in general resins such as dibutyl phthalate and dioctyl phthalate can be used, and the amount used is the total solid content of the coating liquid. To 20 wt% or less, preferably 10 wt% or less. As leveling agents, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain can be used, and the amount used is based on the total solid content of the coating liquid. 3% by weight or less is appropriate.

The crosslinkable protective layer of the present invention comprises, for example, a coating liquid containing at least a trifunctional or higher radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. It is formed by coating and curing on the aforementioned charge transport layer.
When the radically polymerizable monomer to be used is a liquid, such a coating liquid can be applied by dissolving other components in the liquid. However, if necessary, it is diluted with a solvent and applied.

  Solvents used at this time include alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, tetrahydrofuran, dioxane and propyl ether. Ethers such as dichloromethane, halogens such as dichloromethane, dichloroethane, trichloroethane, and chlorobenzene, aromatics such as benzene, toluene, and xylene, and cellosolves such as methyl cellosolve, ethyl cellosolve, and cellosolve acetate. These solvents may be used alone or in combination of two or more. The dilution ratio with the solvent varies depending on the solubility of the composition, the coating method, and the target film thickness, and is arbitrary. The application can be performed by dip coating, spray coating, bead coating, ring coating, or the like.

In the present invention, after the application of such a crosslinkable protective layer coating solution, energy is applied from the outside and cured to form a crosslinkable protective layer. The external energy used at this time is heat, light, radiation, etc. There is.
The heat energy is applied by heating from the coating surface side or the support side using a gas such as air or nitrogen, steam, various heat media, infrared rays or electromagnetic waves.
The heating temperature is preferably 100 ° C. or higher and 170 ° C. or lower. If the heating temperature is lower than 100 ° C., the reaction rate is slow and the curing reaction tends not to be completed completely. At a high temperature exceeding 170 ° C., the curing reaction proceeds non-uniformly, and large strains, a large number of unreacted residues, and reaction termination terminals are generated in the crosslinked protective layer. In order to advance the curing reaction uniformly, it is also effective to complete the reaction by heating at a relatively low temperature of less than 100 ° C. and then heating to 100 ° C. or more.
As light energy, UV irradiation light sources such as high-pressure mercury lamps and metal halide lamps that have an emission wavelength mainly in the ultraviolet region can be used, but a visible light source can be selected according to the absorption wavelength of radically polymerizable substances and photopolymerization initiators. Is also possible.
Irradiation light amount is 50 mW / cm ² or more, preferably 1000 mW / cm ² or less, it takes time for the curing reaction is less than 50 mW / cm ^2. If it is higher than 1000 mW / cm ² , the reaction progresses unevenly, local flaws occur on the surface of the crosslinked protective layer, and a large number of unreacted residues and reaction termination ends occur. In addition, internal stress increases due to rapid crosslinking, which causes cracks and film peeling. Examples of radiation energy include those using electron beams. Among these energies, those using heat and light energy are useful because of the ease of reaction rate control and the simplicity of the apparatus.

The film thickness of the crosslinked protective layer of the present invention is preferably 1 μm or more and 10 μm or less, more preferably 2 μm or more and 8 μm or less. If it is thicker than 10 μm, cracks and film peeling are likely to occur as described above, and if it is 8 μm or less, the margin is further improved, so that the crosslink density can be increased, and material selection and curing that further increase wear resistance. Conditions can be set.
On the other hand, the radical polymerization reaction is prone to oxygen inhibition, that is, the surface in contact with the air is not easily cross-linked or non-uniform due to the effect of radical trapping by oxygen. This effect appears remarkably when the surface layer is less than 1 μm, and a crosslinked protective layer having a thickness less than this thickness is likely to have a reduced wear resistance or uneven wear. In addition, when the crosslinkable protective layer is applied, the lower charge transport layer component is mixed.In particular, if the coating thickness of the crosslinkable protective layer is thin, the contaminants spread throughout the layer, inhibiting the curing reaction and reducing the crosslink density. Bring about a decline. For these reasons, the crosslinkable protective layer of the present invention has good wear resistance and scratch resistance at a film thickness of 1 μm or more. However, when repeatedly used, a part that is locally scraped to the lower charge transport layer is formed. The wear of the portion increases, and the density unevenness of the halftone image tends to occur due to the chargeability and sensitivity fluctuation. Therefore, it is desirable that the film thickness of the cross-linkable protective layer is 2 μm or more for a longer life and higher image quality.

In the configuration in which the charge blocking layer, the moire preventing layer, the photosensitive layer (charge generation layer, charge transport layer) and the crosslinkable protective layer of the electrophotographic photoreceptor of the present invention are sequentially laminated, the outermost crosslinkable protective layer is an organic solvent. On the other hand, when it is insoluble, it indicates that dramatic wear resistance and scratch resistance are achieved.
As a method for testing the solubility in an organic solvent, a drop of an organic solvent having high solubility in a polymer substance, for example, tetrahydrofuran, dichloromethane, or the like, is dropped on the surface layer of the photoconductor, and the surface shape of the photoconductor is dried after natural drying. It can be determined by observing the change with a stereomicroscope.
Highly soluble photoconductors have a phenomenon that the central part of the droplet becomes concave and the surroundings swell up, the charge transport material precipitates and becomes cloudy or cloudy due to crystallization, and the surface swells and then shrinks, causing wrinkles Changes such as the phenomenon to be seen. In contrast, an insoluble photoconductor does not exhibit the above-described phenomenon, and does not change at all as before dropping.

  In the constitution of the present invention, in order to make the crosslinkable protective layer insoluble in the organic solvent, (1) composition of the crosslinkable protective layer coating solution, adjustment of the content ratio thereof, (2) coating of the crosslinkable protective layer Dilution solvent of working solution, adjustment of solid content concentration, (3) Selection of coating method of crosslinkable protective layer, (4) Control of curing conditions of crosslinkable protective layer, (5) Difficult dissolution of lower charge transport layer It is important to control these factors such as sexualization, but it is not achieved by a single factor.

The composition of the crosslinkable protective layer coating solution may be a radical polymerizable compound in addition to the above-described trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. When a large amount of additives such as a binder resin having no functional group, an antioxidant, and a plasticizer is contained, the crosslinking density is reduced, and the cured product resulting from the reaction and phase separation between the additive and the organic solvent are caused. It tends to be soluble.
Specifically, it is important to suppress the total content to 20% by weight or less with respect to the total solid content of the coating liquid. Further, in order not to dilute the crosslinking density, the total content of monofunctional or bifunctional radical polymerizable monomers, reactive oligomers, and reactive polymers is 20% by weight or less based on the trifunctional radical polymerizable monomers. It is desirable. Further, when a large amount of a radically polymerizable compound having a bifunctional or higher-functional charge transporting structure is contained, a bulky structure is fixed in the crosslinked structure by a plurality of bonds, so that distortion is likely to occur. It is easy to become an aggregate. This may cause solubility in organic solvents. Although different depending on the compound structure, the content of the radical polymerizable compound having a bifunctional or higher functional charge transporting structure is preferably 10% by weight or less based on the radical polymerizable compound having a monofunctional charge transporting structure.

As for the diluting solvent of the crosslinkable protective layer coating solution, if a solvent with a slow evaporation rate is used, the remaining solvent may hinder the curing, or increase the amount of the lower layer component mixed. This leads to a decrease in the cured density, which tends to make it soluble in organic solvents.
Specifically, tetrahydrofuran, a mixed solvent of tetrahydrofuran and methanol, ethyl acetate, methyl ethyl ketone, ethyl cellosolve and the like are useful, but are selected in combination with the coating method.

Moreover, regarding the solid content concentration, if it is too low for the same reason, it tends to be soluble in an organic solvent. On the contrary, the upper limit concentration is restricted due to the limitation of the film thickness and the coating solution viscosity.
Specifically, it is desirable to use in the range of 10 to 50% by weight. As a coating method for the cross-linked protective layer, for the same reason, the solvent content at the time of forming the coating film, a method of reducing the contact time with the solvent is preferable, specifically, the spray coating method, the amount of coating liquid A regulated ring coat method is preferred. Also, in order to suppress the amount of the lower layer component mixed in, a polymer charge transport material is used as the charge transport layer, and a crosslinkable protective layer is applied between the photosensitive layer (or charge transport layer) and the crosslinkable protective layer. It is also effective to provide an intermediate layer insoluble in the solvent.

As the curing conditions for the cross-linkable protective layer, if the energy of heating or light irradiation is low, the curing is not completely completed and the solubility in the organic solvent is increased. On the other hand, when cured with very high energy, the curing reaction becomes non-uniform, which tends to increase the number of uncrosslinked parts and radical stopping parts, and to form an aggregate of minute cured products. For this reason, it may show solubility in organic solvents. In order to insolubilize in an organic solvent, the heat curing conditions are preferably 100 to 170 ° C. and 10 minutes to 3 hours, and the curing conditions by UV light irradiation are 50 to 1000 mW / cm ² , 5 seconds to 5 minutes. In addition, it is desirable to control the temperature rise to 50 ° C. or less to suppress non-uniform curing reaction.

An example of a method for making the crosslinkable protective layer constituting the electrophotographic photoreceptor of the present invention insoluble in an organic solvent will be described.
For example, when an acrylate monomer having three acryloyloxy groups and a triarylamine compound having one acryloyloxy group are used as the coating liquid, the usage ratio thereof is 7: 3 to 3: 7. Further, a polymerization initiator is added in an amount of 3 to 20% by weight based on the total amount of these acrylate compounds, and a solvent is further added to prepare a coating solution.

  For example, in the case where the charge transport layer which is the lower layer of the crosslinkable protective layer uses a triarylamine donor as the charge transport material and polycarbonate as the binder resin and the surface layer is formed by spray coating, the above coating liquid As the solvent, tetrahydrofuran, 2-butanone, ethyl acetate and the like are preferable, and the use ratio thereof is 3 to 10 times the total amount of the acrylate compound.

For example, the prepared coating solution is applied by spraying or the like on a photoreceptor in which an intermediate layer, a charge generation layer, and the charge transport layer are sequentially laminated on a support such as an aluminum cylinder. Then, it is naturally dried or dried at a relatively low temperature for a short time (25 to 80 ° C., 1 to 10 minutes) and cured by UV irradiation or heating.
For UV irradiation, uses a metal halide lamp, illuminance 50 mW / cm ² or more, 1000 mW / cm ² or less, preferably about 5 minutes 5 seconds as the time, the drum temperature is controlled so as not to exceed 50 ° C. .
In the case of thermosetting, the heating temperature is preferably 100 to 170 ° C. For example, when a blowing oven is used as a heating means and the heating temperature is set to 150 ° C, the heating time is 20 minutes to 3 hours.
After the curing is completed, the photosensitive material of the present invention is obtained by heating at 100 to 150 ° C. for 10 to 30 minutes to reduce the residual solvent.

  As described above, when a protective layer is formed on the photosensitive layer, there is a case where the neutralizing light does not sufficiently reach the photosensitive layer unless the appropriate protective layer is selected, and the static eliminating action does not work clearly. In addition, the protective layer absorbs the static elimination light, so that it tends to deteriorate, and conversely, there is a case where a residual potential rise is generated. Therefore, in any of the protective layers described above, the transmittance for the static elimination light is 30% or more, preferably 50% or more, and more desirably 85% or more.

  As described above, providing a protective layer on the surface of the photoconductor not only enhances the durability (wear resistance) of each photoconductor, but is also used in a tandem type full-color image forming apparatus as described below. In such a case, a new effect that does not exist in the monochrome image forming apparatus is also produced.

  In the present invention, in order to improve environment resistance, oxidation is performed on each layer such as a protective layer, a charge transport layer, a charge generation layer, a charge blocking layer, and a moire prevention layer, particularly for the purpose of preventing a decrease in sensitivity and an increase in residual potential. An inhibitor can be added. Specific examples are shown below.

(Phenolic compounds)
2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3,5-di-t-butyl-4 -Hydroxyphenyl) propionate, 2,2'-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2'-methylene-bis- (4-ethyl-6-tert-butylphenol), 4, 4'-thiobis- (3-methyl-6-tert-butylphenol), 4,4'-butylidenebis- (3-methyl-6-tert-butylphenol), 1,1,3-tris- (2-methyl-4 -Hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene- -(3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3'-bis (4'-hydroxy-3'-t-butylphenyl) butyric acid] Crycol esters, tocopherols, etc.

(Paraphenylenediamines)
N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N'- Di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine and the like.

(Hydroquinones)
2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2-octadecenyl) ) -5-methylhydroquinone and the like.

(Organic sulfur compounds)
Dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate, and the like.

(Organic phosphorus compounds)
Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine, and the like.

  The said compound is known as antioxidants, such as rubber | gum, a plastic, and fats and oils, and a commercial item can be obtained easily. The addition amount of the antioxidant in the present invention is 0.01 to 10% by weight based on the total weight of the layer to be added.

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

(Image forming apparatus and image forming method)
The image forming apparatus of the present invention has a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα at least on a conductive support at least at 26.2 °. Has diffraction peaks, 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1 A photosensitive layer containing titanyl phthalocyanine crystal having a peak at 0 ° and 28.3 °, a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure An electrophotographic photosensitive member (electrostatic latent image carrier) having a protective layer made of a cured resin, a charging unit, a writing unit (exposure unit), a developing unit, a transfer unit, and a fixing unit. And at least it is necessary Depending appropriately selected other units, for example, it has a cleaning means, charge removing unit, a recycling unit, a controlling unit.

  The image forming method of the present invention includes at least a charging step, a writing step (exposure step), a development step, a transfer step, and a fixing step, and further other steps appropriately selected as necessary, for example, cleaning. Process, charge removal process, recycling process, control process and the like.

  The image forming method of the present invention can be preferably carried out by the image forming apparatus of the present invention, the charging step can be performed by the charging unit, the writing step can be performed by the writing unit, The developing step can be performed by the developing unit, the transfer step can be performed by the transferring unit, the neutralizing step can be performed by the neutralizing unit, and the fixing step can be performed by the fixing unit. The other steps can be performed by the other means.

  The image forming apparatus of the present invention forms an electrostatic latent image with an electrophotographic photosensitive member (electrostatic latent image carrier), charging means for forming an electrostatic latent image on the electrostatic latent image carrier. Writing means, developing means for developing the electrostatic latent image with toner to form a visible image, transfer means for transferring the visible image to a recording medium, and transfer to the recording medium At least fixing means for fixing the transferred image.

<Electrostatic latent image formation>
The electrostatic latent image can be formed, for example, by uniformly charging the surface of the electrostatic latent image carrier and then exposing (writing) imagewise. It can be done by means.
The electrostatic latent image forming means includes, for example, at least a charger that uniformly charges the surface of the electrostatic latent image carrier and an exposure device that exposes the surface of the electrostatic latent image carrier imagewise. Prepare.

<Charging means>
The charger is not particularly limited and may be appropriately selected depending on the purpose. For example, a known contact charging device including a conductive or semiconductive roll, brush, film, rubber blade, etc. And non-contact chargers using corona discharge such as corotron and scorotron (including proximity-type non-contact chargers having a gap of 100 μm or less between the surface of the photoreceptor and the charger).

The electric field strength applied to the electrostatic latent image carrier by the charger is preferably 20 to 60 V / μm, and more preferably 30 to 50 V / μm. The higher the electric field strength applied to the photoconductor, the better the dot reproducibility. However, if the electric field strength is too high, problems such as dielectric breakdown of the photoconductor and carrier adhesion during development may occur.
The electric field strength is expressed by the following mathematical formula (1).
Electric field strength (V / μm) = SV / G (1)
In the above formula (1), SV represents the surface potential (V) in the unexposed portion of the electrostatic latent image carrier at the development position. G represents the film thickness (μm) of the photosensitive layer including at least the photosensitive layer (charge generation layer and charge transport layer).

<Writing means>
The writing can be performed, for example, by exposing the surface of the latent electrostatic image bearing member imagewise using the exposure device. The type of the exposure device is not particularly limited and may be appropriately selected according to the purpose. For example, various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system. Is mentioned. In the present invention, a back light system in which imagewise exposure is performed from the back surface side of the electrostatic latent image carrier may be adopted.

  As the light source, a light source capable of ensuring high luminance such as a light emitting diode (LED), a semiconductor laser (LD), or electroluminescence (EL) is used. Depending on the resolution of the light source (write light) to be used, the resolution of the electrostatic latent image and thus the toner image to be formed is determined, and the higher the resolution, the clearer the image. However, if writing is performed at a higher resolution, writing takes longer, so writing with one writing light source is limited by the drum linear speed (process speed). Therefore, when there is one writing light source, a resolution of about 2400 dpi is the upper limit. When there are a plurality of writing light sources, each may share a writing area, and “2400 dpi × number of writing light sources” is practically the upper limit. Among these light sources, light emitting diodes and semiconductor lasers have high irradiation energy and are used favorably.

<Developing means>
The development can be performed by developing the electrostatic latent image with toner to form a visible image. As the toner, a toner having the same polarity as the charged polarity of the photoreceptor is used, and the electrostatic latent image is developed by reversal development (negative / positive development). There are two methods, a one-component method in which development is performed with toner alone and a two-component method in which a two-component developer comprising a toner and a carrier is used. Either method can be used favorably.

<Transfer means>
The transfer means is a means for transferring the visible image onto a recording medium. The transfer means can be transferred onto the intermediate transfer body using a method of directly transferring the visible image from the surface of the photoreceptor to the recording medium and an intermediate transfer body. There is a method in which a visual image is primarily transferred by a primary transfer unit and then the visible image is secondarily transferred onto the recording medium by a secondary transfer unit. Either aspect can be used satisfactorily, but the former (direct transfer) method with a small number of transfers is preferred when the adverse effect of the transfer is great when the image quality is improved.

  The transfer can be performed by the transfer unit. For example, the visible image can be transferred by charging the electrostatic latent image carrier (electrophotographic photosensitive member) with a transfer charger. The transfer unit is not particularly limited, and can be appropriately selected from known transfer units according to the purpose. For example, a transfer conveyance belt that can simultaneously convey a recording medium can be preferably cited. It is done.

  The transfer means (the primary transfer means and the secondary transfer means) peels and charges the visible image formed on the electrostatic latent image carrier (electrophotographic photosensitive member) to the recording medium side. It is preferable to have at least a transfer charger. There may be one transfer means or two or more transfer means. Examples of the transfer charger include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device. The recording medium is not particularly limited and can be appropriately selected from known recording media (recording paper).

  The transfer charger may be a transfer belt or a transfer roller, but it is desirable to use a contact type such as a transfer belt or transfer roller that generates less ozone. As a voltage / current application method at the time of transfer, either a constant voltage method or a constant current method can be used, but the transfer charge amount can be kept constant, and a constant voltage with excellent stability can be used. The current method is more desirable. As such a transfer member, a known member can be used as long as the structure of the present invention can be satisfied.

  Depending on the surface potential of the photoreceptor after transfer (the surface potential of the difference entering the charge eliminating portion), the amount of charge passing through the photoreceptor per cycle of image formation varies greatly. The larger this is, the greater the influence on the electrostatic fatigue of the photoreceptor in repeated use.

  This passing charge amount corresponds to the amount of charge flowing in the film thickness direction of the photoreceptor. As an operation in the image forming apparatus of the photoconductor, the main charger is charged to a desired charging potential (in most cases, negatively charged), and optical writing is performed based on an input signal corresponding to the original. At this time, photocarriers are generated in the portion where writing has been performed, neutralizing the surface charge, and decreasing the potential. At this time, the amount of charge depending on the amount of generated photocarriers flows in the direction of the photoreceptor thickness. On the other hand, a region where optical writing is not performed, a so-called non-writing portion, proceeds to a charge removal process through a development process and a transfer process (a cleaning process is performed before that if necessary). Here, when the surface potential of the photoconductor is close to the potential applied by main charging (excluding dark decay), the amount of charge is almost the same as that in the area where optical writing is performed. Will flow into. In general, since the current document has a low writing rate, in this method, the amount of charge passing through the photoreceptor in repeated use is mostly current that flows in the static elimination process. For example, if the writing rate is 10%. The current flowing in the static elimination process accounts for 90% of the total.

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

  On the other hand, there is a concept of not performing the static neutralization, but if the main charger is not large in charging ability, the charging cannot be stabilized and a problem such as an afterimage may occur. The passing charge of the photoconductor is generated by the movement of a photocarrier generated by light irradiation due to a potential charged on the surface of the photoconductor (that is, an electric field generated by the potential). Therefore, if the photoreceptor surface potential can be attenuated by means other than light, the amount of passing charge per rotation of the photoreceptor (one cycle of image formation) can be reduced.

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

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

<Fixing means>
The fixing may be performed each time the visible image transferred to the recording medium is fixed by using a fixing device and transferred to the recording medium for each color toner, or the toner is stacked on each color toner. May be performed simultaneously at the same time.
There is no restriction | limiting in particular as said fixing device, Although it can select suitably according to the objective, A well-known heating-pressing means is suitable. Examples of the heating and pressing means include a combination of a heating roller and a pressure roller, a combination of a heating roller, a pressure roller, and an endless belt. The heating in the heating and pressing means is usually preferably 80 ° C to 200 ° C. In the present invention, for example, a known optical fixing device may be used together with or in place of the fixing step and the fixing unit depending on the purpose.

<Static removal means>
The neutralization unit is not particularly limited as long as it can neutralize the electrostatic latent image carrier, and can be appropriately selected from known neutralization units. For example, fluorescent 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.

<Others>
The cleaning means is not particularly limited as long as it can remove the electrophotographic toner remaining on the electrostatic latent image carrier, and can be appropriately selected from known cleaners. Suitable examples include magnetic brush cleaners, electrostatic brush cleaners, magnetic roller cleaners, blade cleaners, brush cleaners, and web cleaners.

  The recycling means is a step of recycling the electrophotographic color toner removed by the cleaning means, for example, to the developing means, and includes a known conveying means.

  The control means is a process for controlling the respective steps, and can be suitably performed by the control means. The control means is not particularly limited as long as it can control the movement of each means, and can be appropriately selected according to the purpose. Examples thereof include devices such as sequencers and computers.

  Here, one aspect of the image forming apparatus of the present invention will be described with reference to FIG. FIG. 5 is a schematic diagram for explaining the image forming apparatus of the present invention, and modifications as described later also belong to the category of the present invention.

In FIG. 5, a photosensitive member (1) as an electrostatic latent image carrier has a diffraction peak (± 0.2 °) at a Bragg angle 2θ with respect to a characteristic X-ray (wavelength 1.542 mm) of CuKα on a conductive support. ) Having a maximum diffraction peak at least 26.2 °, 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 A photosensitive layer containing titanyl phthalocyanine crystals having peaks at °, 23.2 °, 27.1 ° and 28.3 °, a trifunctional or higher functional radical polymerizable monomer having no charge transporting structure and charge transporting property A protective layer made of a cured resin obtained by curing a monofunctional radically polymerizable compound having a structure is provided.
The photoreceptor (1) has a drum shape, but may be a sheet shape or an endless belt shape.

  As the charging member (charging device) (3) as a charging means, a wire type charging device or a roller-shaped charging device is used. When high-speed charging is required, a scorotron charger is preferably used. In a compact or tandem image forming apparatus that uses a plurality of photoconductors described later, acid gas (NOx, SOx, etc.) A roller-shaped charger that generates less ozone is effectively used. Although the photosensitive member is charged by this charger, the higher the electric field strength applied to the photosensitive member, the better the dot reproducibility. Therefore, it is desirable to apply an electric field strength of 20 V / μm or more. . However, there is a possibility that problems such as dielectric breakdown of the photosensitive member and carrier adhesion during development occur, and the upper limit is approximately 60 V / μm or less, more preferably 50 V / μm or less.

  In addition, a light source capable of ensuring high luminance, such as a light emitting diode (LED), a semiconductor laser (LD), or electroluminescence (EL), is used for the image exposure unit (5) that is an exposure means. Depending on the resolution of the light source (writing light), the resolution of the formed electrostatic latent image, and thus the toner image, is determined. The higher the resolution, the clearer the image. However, if writing is performed at a higher resolution, writing takes longer, so writing with one writing light source is limited by the drum linear speed (process speed). Therefore, when there is one writing light source, a resolution of about 1200 dpi is the upper limit. When there are a plurality of write light sources, each of them only has to bear a write area, and the upper limit is substantially “1200 dpi × number of write light sources”. Among these light sources, light emitting diodes and semiconductor lasers have high irradiation energy and are used favorably.

  The developing unit (6) which is a developing means has at least one developing sleeve. In the developing unit (6), toner having the same polarity as the charged polarity of the photoreceptor is used, and the electrostatic latent image is developed by reversal development (negative / positive development). Depending on the light source used in the previous image exposure unit, in the case of a digital light source used in recent years, there is generally a reversal development method in which toner development is performed on the writing portion in response to a low image area ratio. This is advantageous in view of the life of the light source. There are two methods, a one-component method in which development is performed with toner alone and a two-component method in which a two-component developer comprising a toner and a carrier is used. Either method can be used favorably.

  Further, as the transfer charger (10) which is a transfer means, a transfer belt or a transfer roller can be used, and it is desirable to use a contact type such as a transfer belt or a transfer roller with a small amount of ozone generation. As a voltage / current application method at the time of transfer, either a constant voltage method or a constant current method can be used, but the transfer charge amount can be kept constant, and a constant voltage with excellent stability can be used. The current method is more desirable. In particular, by subtracting the current that flows from the power supply member (high-voltage power supply) that supplies electric charge to the transfer member and does not flow into the photosensitive member, the current to the photosensitive member is subtracted. A method of controlling the value is preferred.

  The transfer current is a current based on the amount of charge required to peel off the toner electrostatically attached to the photosensitive member and transfer it to a transfer target (transfer paper or intermediate transfer member). In order to avoid transfer defects such as transfer residue, it is only necessary to increase the transfer current. However, in the case of using negative and positive development, charging with a polarity opposite to the charging polarity of the photosensitive member is given. As a result, the electrostatic fatigue of the photoconductor becomes remarkable. The larger the transfer current, the more advantageous it is because a charge amount exceeding the electrostatic adhesion force between the photoconductor and the toner can be given. However, if a certain threshold value is exceeded, a discharge phenomenon occurs between the transfer member and the photoconductor, and it becomes fine. As a result, the developed toner image is scattered. For this reason, the upper limit is a range in which this discharge phenomenon does not occur. This threshold varies depending on the gap (distance) between the transfer member and the photoconductor, the material constituting the both, and the like, but the discharge phenomenon can be avoided by using it at about 200 μA or less. Therefore, the upper limit value of the transfer current is about 200 μA.

In addition, the toner image formed on the photoconductor is transferred onto the transfer paper to become an image on the transfer paper. At this time, there are two methods. One is a method of directly transferring a toner image developed on the surface of the photosensitive member as shown in FIG. 5 to the transfer paper, and the other is a transfer of the toner image from the photosensitive member to the intermediate transfer member. It is a method of transferring to paper. Either case can be used in the present invention. As such a transfer member, a known member can be used as long as the structure of the present invention can be satisfied.
Further, by controlling the transfer current as described above, reducing the photoreceptor surface potential after transfer (the unexposed portion of the writing light) reduces the amount of charge passing through the photoreceptor per one cycle of image formation. Can be used effectively in the present invention.

  The light source such as the static elimination lamp (2) is only required to neutralize the electrostatic latent image carrier, and can be appropriately selected from known static eliminators. For example, a semiconductor laser (LD), Electroluminescence (EL) etc. are mentioned suitably. In particular, the use of a light source having a wavelength that the metal oxide contained in the intermediate layer of the photoreceptor does not absorb makes the effect of the present invention more remarkable and can be used beneficially.

  A semiconductor laser (LD), electroluminescence (EL), or the like, or a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a xenon lamp, or the like can be used. In order to specify the wavelength, various 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 in combination with the above light source. .

In FIG. 5, reference numeral 8 is a registration roller, 11 is a separation charger, and 12 is a separation claw.
The toner developed on the photosensitive member (1) by the developing unit (6) is transferred to the transfer paper (9). If toner remaining on the photosensitive member (1) is generated, the toner is cleaned by a cleaning unit. It is removed from the photoreceptor by some fur brush (14) and blade (15). The cleaning may be performed only with a cleaning brush, and as such a cleaning brush, known ones such as a fur brush and a mag fur brush are used.

Next, FIG. 6 is a schematic diagram for explaining the tandem type full-color image forming apparatus of the present invention, and the following modifications also belong to the category of the present invention.
In FIG. 6, reference numerals (16Y), (16M), (16C), and (16K) denote drum-shaped photoconductors. ) As a diffraction peak (± 0.2 °) with a Bragg angle 2θ of at least 26.2 ° and a maximum diffraction peak of 9.3 °, 10.5 °, 13.2 °, 15.1 ° 15.6 [deg.], 16.1 [deg.], 20.7 [deg.], 23.2 [deg.], 27.1 [deg.], And 28.3 [deg.], And a photosensitive layer containing a titanyl phthalocyanine crystal having a peak, and at least a charge transporting structure A protective layer made of a cured resin obtained by curing a trifunctional or higher-functional radical polymerizable monomer that does not have and a monofunctional radical polymerizable compound having a charge transport structure is provided.

The photoconductors (16Y), (16M), (16C), and (16K) can rotate in the direction of the arrow in FIG. 6, and around the chargers (17Y), (17M), (17C) at least in the order of rotation. , (17K), developing means (19Y), (19M), (19C), (19K) having at least one developing sleeve, cleaning member (20Y), (20M), (20C), (20K), static elimination means (27Y), (27M), (27C), and (27K) are arranged. The chargers (17Y), (17M), (17C), and (17K) are chargers that constitute a charging device for uniformly charging the surface of the photoreceptor. From the surface of the photoreceptor between the chargers (17Y), (17M), (17C), (17K) and the developing means (19Y), (19M), (19C), (19K), an exposure unit (18Y) , (18M), (18C), and (18K) are irradiated with laser light, and electrostatic latent images are formed on the photoconductors (16Y), (16M), (16C), and (16K). Yes.
Then, the four image forming elements (25Y), (25M), (25C), and (25K) centering on such photoconductors (16Y), (16M), (16C), and (16K) serve as transfer materials. They are juxtaposed along the transfer conveyance belt (22) which is a conveyance means. The transfer / conveying belt (22) includes developing means (19Y), (19M), (19C), (19K) and a cleaning member (20Y) of the image forming units (25Y), (25M), (25C), (25K). , (20M), (20C), and (20K) are in contact with the photosensitive member (16Y), (16M), (16C), and (16K), and contact the back side of the photosensitive member side of the transfer conveyance belt (22). Transfer brushes (21Y), (21M), (21C), and (21K) for applying a transfer bias are arranged on the surface (back surface). Each of the image forming elements (25Y), (25M), (25C), and (25K) is different in the color of the toner inside the developing device, and the others are the same in configuration.

  In the full-color image forming apparatus having the configuration shown in FIG. 6, the image forming operation is performed as follows. First, in each of the image forming elements (25Y), (25M), (25C), and (25K), an electrostatic latent image is formed on the photoconductors (16Y), (16M), (16C), and (16K). It has become. Then, the photoreceptors (16Y), (16M), (16C), and (16K) rotate, and the photoreceptors are charged by the chargers (17Y), (17M), (17C), and (17K). The At this time, in order to form a high-definition latent image, charging is performed so that the electric field strength of the photoreceptor is 20 V / μm or more, preferably 60 V μm or less, more preferably 50 V / μm or less.

  Next, writing is performed by writing at a resolution of 1200 dpi or more, preferably 2400 dpi or more by laser light at the exposed portions (18Y), (18M), (18C), and (18K) arranged outside the photoreceptor. An electrostatic latent image corresponding to each color image is formed. As the writing light source, as described above, a light source suitable for an arbitrary photoconductor is used. In this case as well, 2400 dpi writing is generally the upper limit for one writing light source.

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

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

Further, residual toner remaining on each of the photoconductors (16Y), (16M), (16C), and (16K) without being transferred by the transfer unit is removed from the cleaning devices (20Y), (20M), (20C), ( 20K).
Subsequently, excess residual charges on the photosensitive member are removed by the charge eliminating members (27Y), (27M), (27C), and (27K). Thereafter, charging is performed uniformly by the charger, and the next image formation is performed.

  In the example of FIG. 6, the image forming elements are arranged in the order of Y (yellow), M (magenta), C (cyan), and K (black) from the upstream side to the downstream side in the transfer 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 image forming elements other than black ((25Y), (25M), (25C)). .

  Further, as described above, the surface of the photoreceptor after transfer is preferably charged to 100 V or less on the polarity side charged by the main charger, more preferably charged to the reverse polarity side, and to the reverse polarity side. It is particularly preferable to charge to 100 V or less. As a result, an increase in residual potential due to repeated use of the photoreceptor can be reduced.

The image forming means as described above may be fixedly incorporated in a copying apparatus, a facsimile, or a printer, but may be incorporated in these apparatuses in the form of a process cartridge.
A process cartridge is a single device (part) that contains a photosensitive member, and further includes an electrostatic latent image forming unit, a developing unit, a transfer unit, a cleaning unit, a charge eliminating unit, and the like. There are many shapes and the like of the process cartridge, but a general example is shown in FIG.
The photoreceptor (101) has a maximum diffraction of at least 26.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα on a conductive support. 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1 ° A photosensitive layer containing a titanyl phthalocyanine crystal having a peak at 28.3 °; a tri- or higher functional radical polymerizable monomer having no charge transport structure; and a monofunctional radical polymerizable compound having a charge transport structure. A protective layer made of a cured resin cured product is provided.

  A light source capable of writing is used for the image exposure unit (103), and an arbitrary charger is used for the charger (102). In FIG. 7, reference numeral 104 denotes a developing means having at least one developing sleeve, 105 denotes a transfer body, 106 denotes a transfer means, 107 denotes a cleaning means, and 108 denotes a charge removal member.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to the following Example at all. “Parts” are all parts by mass.

(Synthesis Example 1)
[Synthesis of titanyl phthalocyanine crystal precursor]
A pigment was prepared according to the synthesis method described in JP-A-2001-19871.
That is, 29.2 g of 1,3-diiminoisoindoline and 200 ml of sulfolane are mixed, and 20.4 g of titanium tetrabutoxide is added dropwise under a nitrogen stream. After completion of the dropwise addition, the temperature was gradually raised to 180 ° C., and the reaction was carried out by stirring for 5 hours while maintaining the reaction temperature between 170 ° C. and 180 ° C. After the reaction is complete, the mixture is allowed to cool, and then the precipitate is filtered, washed with chloroform until the powder turns blue, then washed several times with methanol, then washed several times with hot water at 80 ° C. and dried. Crude titanyl phthalocyanine was obtained.
Crude titanyl phthalocyanine is dissolved in 20 times the amount of concentrated sulfuric acid, added dropwise to 100 times the amount of ice water with stirring, the precipitated crystals are filtered, and then ion-exchanged water (pH: 7.) until the washing solution becomes neutral. (0, specific conductivity: 1.0 μS / cm), washing with water was repeated to obtain a titanyl phthalocyanine pigment wet cake (water paste). The pH value of the ion-exchanged water after washing was 6.8, and the specific conductivity was 2.6 μS / cm.
As a diffraction peak of Bragg angle 2θ with respect to Cu-Kα ray (wavelength 1.542 mm) of this amorphous titanyl phthalocyanine, the half-value width of the diffraction peak of 7.0 ° to 7.5 ° was 1 ° or more.

40 g of the obtained wet cake (water paste) was put into 200 g of tetrahydrofuran, stirred for 4 hours, filtered and dried to obtain titanyl phthalocyanine powder (precursor).
The solid content concentration of the wet cake was 15% by mass. The crystal conversion solvent was used in a mass ratio of 33 times that of the wet cake. In addition, the halogen-containing compound is not used for the raw material of the synthesis example 1.
When the X-ray diffraction spectrum (XD spectrum) of the obtained titanyl phthalocyanine powder was measured with a commercially available X-ray diffractometer (Rigaku Denki: RINT1100) under the following measurement conditions, Cu-Kα ray (CuKα characteristic X-ray) ) The Bragg angle 2θ with respect to (wavelength 1.542 mm) has a maximum peak at 27.2 ± 0.2 °, a peak at the minimum angle 7.3 ± 0.2 °, and a peak at 7.3 °. There was no peak between the 4 ° peaks, and no peaks at 26.3 °. As a result, an X-ray diffraction spectrum (XD spectrum) is shown in FIG.
A part of the obtained water paste was dried at 80 ° C. under reduced pressure (5 mmHg) for 2 days to obtain a low crystalline titanyl phthalocyanine powder. FIG. 9 shows an X-ray diffraction spectrum (XD spectrum) of the dry powder of the water paste.

<X-ray diffraction spectrum measurement conditions>
X-ray tube: Cu
Voltage: 50kV
Current: 30mA
Scanning speed: 2 ° / min Scanning range: 3 ° -40 °
Time constant: 2 seconds

[Synthesis of titanyl phthalocyanine crystal by crystal transformation of precursor]
Subsequently, the precursor obtained above was treated with an organic solvent. 40 g of the precursor synthesized above was immersed in 400 g of tetrahydrofuran for 1 week in a dark place. One week later, titanyl phthalocyanine crystals were separated by filtration and vacuum-dried at 100 ° C. for 1 day to obtain titanyl phthalocyanine crystals used in the present invention (referred to as crystal 1).
FIG. 10 shows an X-ray diffraction spectrum obtained by measuring the obtained crystal 1 in the same manner as described above.
The X-ray diffraction spectrum in FIG. 10 has a maximum diffraction peak at 26.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα. 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1 °, and 28.3 It was found that there was also a peak at °.

(Synthesis Examples 2 to 7)
In the precursor synthesis in Synthesis Example 1, titanyl phthalocyanine crystals were synthesized in the same manner as in Synthesis Example 1 except that the organic solvents described in Table 1 below were used instead of tetrahydrofuran. Corresponding to Synthesis example 2 to Synthesis example 7, they are referred to as Crystal 2 to Crystal 7, respectively.

The precursors obtained in Synthesis Examples 2 to 7 all showed the same spectrum as the X-ray diffraction spectrum shown in FIG.
Further, X-ray diffraction spectra of the obtained crystals 2 to 7 were measured under the above conditions, and almost the same spectrum as the X-ray diffraction spectrum shown in FIG. 10 was obtained for each crystal.

(Synthesis Example 8)
The precursor obtained in the same manner as in Synthesis Example 1 was treated with an organic solvent as follows to obtain a titanyl phthalocyanine crystal.
40 g of the precursor synthesized in Synthesis Example 1 was charged into a ball mill pot having a diameter of 150 mm together with 400 g of 2-butanone. Into this, 3.5 kg of zirconia balls having a diameter of 2 mm were charged and milled for 24 hours.
After the organic solvent treatment, the titanyl phthalocyanine crystal was separated by filtration and vacuum-dried at 100 ° C. for 1 day to obtain the titanyl phthalocyanine crystal of the present invention (referred to as crystal 8).
The obtained crystal 8 was subjected to measurement of an X-ray diffraction spectrum under the same conditions as above, and a spectrum similar to the X-ray diffraction spectrum shown in FIG. 10 was obtained.

(Synthesis Example 9)
The precursor obtained in the same manner as in Synthesis Example 1 was subjected to the following crystal conversion treatment to obtain a titanyl phthalocyanine crystal.
40 g of the obtained precursor was put into a ball mill pot having a diameter of 150 mm. Into this, 3.5 kg of zirconia balls having a diameter of 2 mm were charged and milled for 48 hours.
After the crystal conversion treatment, the titanyl phthalocyanine crystal was separated from the ball to obtain the titanyl phthalocyanine crystal of the present invention (referred to as crystal 9).
The obtained crystal 9 was subjected to measurement of an X-ray diffraction spectrum under the same conditions as above, and a spectrum similar to the X-ray diffraction spectrum shown in FIG. 10 was obtained.

(Synthesis Example 10)
In the precursor synthesis in Synthesis Example 1, a titanyl phthalocyanine crystal was synthesized (referred to as Crystal 10) in the same manner as in Synthesis Example 1 except that 2-butanone was used instead of tetrahydrofuran.
An X-ray diffraction spectrum obtained by measuring the obtained precursor under the same conditions as above is shown in FIG. FIG. 12 shows an X-ray diffraction spectrum obtained by measuring the obtained titanyl phthalocyanine crystal under the same conditions as above.
The X-ray diffraction spectrum shown in FIG. 12 has a maximum diffraction peak at 26.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα. 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1 °, and 28.3 It has a peak at ° and is the same spectrum as the X-ray diffraction spectrum shown in FIG.

(Synthesis Example 11)
A titanyl phthalocyanine crystal was synthesized according to Production Example 1 described in JP-B-5-31137.
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 ° C. for 3 hours with stirring, then allowed to cool, filtered hot at 100 to 130 ° C., and washed with 200 ml of α-chloronaphthalene heated to 100 ° C.
The resulting crude cake. It is washed with 300 ml of α-chloronaphthalene and then with 300 ml of methanol at room temperature, followed by hot washing with 800 ml of methanol for 1 hour three times, and the resulting cake is suspended in 700 ml of water and subjected to hot washing for 2 hours. went. The hot wash was repeated until the pH of the hot wash filtrate was approximately 7. Thereafter, an operation of carrying out hot washing for 2 hours in 700 ml of N-methylpyrrolidone at 140 to 145 ° C. was carried out four times. Subsequently, it was washed with 800 ml of methanol twice, filtered, and vacuum-dried at 80 ° C. for 1 day to obtain a titanyl phthalocyanine crystal (referred to as crystal 11).
The X-ray diffraction spectrum of the obtained titanyl phthalocyanine crystal is the same as that shown in FIG. 1 of JP-B-5-31137, and the same spectrum as the X-ray diffraction spectrum shown in FIG. 10 of Synthesis Example 1 in the present invention. was gotten.

  The production method of Synthesis Example 11 is different from the production method of Synthesis Example 1. That is, the Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 波長) of CuKα obtained by crystal conversion of amorphous titanyl phthalocyanine having a half-width of a diffraction peak of 7.0 to 7.5 ° of 1 ° or more. Diffraction peak (± 0.2 °) having a maximum diffraction peak at least 27.2 °, and further having major peaks at 9.4 °, 9.6 °, 24.0 °, and most As a diffraction peak on the low angle side, it has a peak at 7.3 °, no peak between the peak at 7.3 ° and the peak at 9.4 °, and no peak at 26.3 ° The production method is significantly different from Synthesis Example 1 in that titanyl phthalocyanine crystal is not used as a precursor. The raw material of Synthesis Example 11 contains titanium halide.

(Synthesis Example 12)
A titanyl phthalocyanine crystal was synthesized according to Production Example 4 described in JP-B-5-31137.
That is, 46 g of phthalodinitrile was charged into 250 ml of α-chloronaphthalene and dissolved by heating. Then, 10 ml of titanium tetrachloride was added dropwise, stirred at 150 ° C. for 30 minutes, then gradually heated, and heated at 220 ° C. for 2 hours. Heating and stirring were performed. Thereafter, the mixture was allowed to cool with stirring, and when the temperature of the reaction system dropped to 100 ° C., it was filtered hot, then hot suspended in 600 ml of methanol and suspended in boiling with hot water once each, and then 600 ml of N -Hot suspension with methylpyrrolidone at 120 ° C for 1 hour, hot filtration, hot suspension with 800 ml of methanol, filtration and vacuum drying for 1 day at 80 ° C to obtain titanyl phthalocyanine crystals (crystals 12 and To do).
The X-ray diffraction spectrum of the obtained titanyl phthalocyanine crystal is the same as that shown in FIG. 7 of JP-B-5-31137, and the same spectrum as the X-ray diffraction spectrum shown in FIG. 10 of Synthesis Example 1 in the present invention. was gotten.

  The production method of Synthesis Example 12 is different from the production method of Synthesis Example 1. That is, the Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 波長) of CuKα obtained by crystal conversion of amorphous titanyl phthalocyanine having a half-width of a diffraction peak of 7.0 to 7.5 ° of 1 ° or more. Diffraction peak (± 0.2 °) having a maximum diffraction peak at least 27.2 °, and further having major peaks at 9.4 °, 9.6 °, 24.0 °, and most As a diffraction peak on the low angle side, it has a peak at 7.3 °, no peak between the peak at 7.3 ° and the peak at 9.4 °, and no peak at 26.3 ° The production method is significantly different from Synthesis Example 1 in that titanyl phthalocyanine crystal is not used as a precursor. The raw material of Synthesis Example 12 contains titanium halide.

(Comparative Synthesis Example 1)
An α-type titanyl phthalocyanine crystal was synthesized according to the synthesis method described in Examples of JP-A-61-239248.
That is, a mixture of 40 g of phthalodinitrile, 18 g of titanium tetrachloride and 500 m of α-chloronaphthalene was heated and stirred at 240 to 250 ° C. for 3 hours under a nitrogen stream to complete the reaction. Thereafter, filtration was performed to obtain a product dichlorotitanium phthalocyanine. The obtained dichlorotitanium phthalocyanine was heated to reflux with 300 m of concentrated aqueous ammonia and 300 m of pyridine for 1 hour to obtain 18 g of α-type titanyl phthalocyanine as the target product. The product was thoroughly washed with acetone in a Soxhlet extractor. After washing, vacuum drying was performed at 60 ° C. for 1 day to obtain titanyl phthalocyanine crystals (referred to as crystals 13).

[Measurement of X-ray diffraction spectrum]
FIG. 12 is a diagram showing an example of an X-ray diffraction spectrum of the precursor obtained in Synthesis Example 10. As is clear from FIG. 12, the precursor obtained in Synthesis Example 10 is 27.2 ° as a diffraction peak with a Bragg angle 2θ (± 0.2 °) with respect to the Cu—Kα ray (wavelength 1.542 mm). Although it has the maximum diffraction peak, it has a diffraction peak at 7.5 ° as the lowest diffraction peak.

3% by mass of the crystal 13 produced in Comparative Synthesis Example 1 was added to the precursor obtained in Synthesis Example 1 and the precursor obtained in Synthesis Example 10, respectively, and mixed in a mortar to obtain a mixed powder. . Each was measured for X-ray diffraction spectra under the same conditions as above.
FIG. 13 shows the X-ray diffraction spectrum of the powder containing the precursor of Synthesis Example 1, and FIG. 14 shows the X-ray diffraction spectrum of the powder containing the precursor of Synthesis Example 10. In the spectrum of FIG. 13, it can be seen that there are two 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. 14, the low angle side peak exists only at 7.5 °, which is clearly different from the spectrum of FIG.

(Production Example 1)
[Preparation of Dispersion 1]
Next, a dispersion of titanyl phthalocyanine crystals synthesized by the present invention was prepared. A dispersion having the following composition was prepared by bead milling under the conditions shown below.
-Titanyl phthalocyanine crystal (crystal 1) produced in Pigment Production Example 1 48 parts by mass-Polyvinyl butyral (manufactured by Sekisui Chemical Co., Ltd., BX-1) ... 32 parts by mass-2-butanone ... 720 masses Part

A zirconia ball having a diameter of 0.5 mm was used in a commercially available bead mill disperser (manufactured by VMA-GETZMANN GMBH, DISPERMAT SL, rotor diameter 50 mm, dispersion chamber capacity 125 ml).
First, a 2-butanone solution in which polyvinyl butyral was dissolved was put into a circulation tank and circulated, and it was confirmed that the resin liquid was filled in the circulation system and returned to the circulation tank. Next, all the pigment was charged into the circulation tank, and after stirring in the circulation tank, the rotor rotation speed was 3000 rpm. p. m. Circulated and dispersed for 300 minutes.

After the dispersion was completed, the mill base was discharged from the bead mill disperser, and further 2060 parts by mass of 2-butanone was added, and all the mill base remaining in the disperser was discharged simultaneously with the dilution to prepare a dispersion (hereinafter referred to as “Dispersion 1”). And).
Part of the produced dispersion liquid 1 was dried up to obtain a powder. Using this, an X-ray diffraction spectrum was measured under the same conditions as described above. The obtained spectrum was the same as that of “Crystal 1”, and it was found that the crystal was stable even when dispersed.

(Production Examples 2 to 12)
[Preparation of dispersions 2 to 12]
Dispersions 2 to 12 were produced in the same manner as in Production Example 1 except that the titanyl phthalocyanine crystal used in Production Example 1 was changed from “Crystal 1” to “Crystal 2” to “Crystal 12”. In addition, the produced dispersion was made into dispersion 2-12 according to the crystal numbers 2-12 used, respectively.

(Production Example 13)
[Preparation of Dispersion 13]
A dispersion 13 was produced in the same manner as in Production Example 1 except that the titanyl phthalocyanine crystal used in Production Example 1 was changed from “Crystal 1” to the precursor of Synthesis Example 10.

(Production Example 14)
[Preparation of Dispersion 14]
A dispersion 14 was produced in the same manner as in Production Example 1, except that the titanyl phthalocyanine crystal used in Production Example 1 was changed from “Crystal 1” to “Crystal 13”.

Next, a synthesis example of a monofunctional radically polymerizable compound having a charge transporting structure (compound having a monofunctional charge transporting structure) used for the cross-linked charge transporting layer will be described.
(Synthesis example of a compound having a monofunctional charge transporting structure)
A compound having a monofunctional charge transporting structure was synthesized as follows. (Note that the compound having a monofunctional charge transporting structure in the present invention is synthesized, for example, by the method described in Japanese Patent No. 3164426. Can do.)

(1) Synthesis of hydroxy group-substituted triarylamine compound [the following structural formula (B)] 113.85 parts (0.3 mol) of a methoxy group-substituted triarylamine compound represented by the following structural formula (A) and iodination To 138 parts (0.92 mol) of sodium, 240 parts of sulfolane was added and heated to 60 ° C. in a nitrogen stream. In this liquid, 99 parts (0.91 mol) of trimethylchlorosilane was added dropwise over 1 hour and stirred at a temperature of about 60 ° C. for 4 and a half hours to complete the reaction.

About 1500 parts of toluene was added to the reaction solution, cooled to room temperature, and washed repeatedly with water and an aqueous sodium carbonate solution. Thereafter, the solvent was removed from the toluene solution, and purification was performed by column chromatography (adsorption medium: silica gel, developing solvent: toluene: ethyl acetate = 20: 1). Cyclohexane was added to the obtained pale yellow oil to precipitate crystals.
As a result, 88.1 parts (yield = 80.4%) of white crystals of the following structural formula (B) were obtained.

  The melting point of the obtained white crystals was 64.0-66.0 ° C. The elemental analysis values of the white crystals are shown in Table 2 below together with the calculated values.

(2) Synthesis example of triarylamino group-substituted acrylate compound (compound corresponding to the exemplified compound No. 54)
82.9 parts (0.227 mol) of the hydroxy group-substituted triarylamine compound [Structural Formula (B)] obtained in (1) above was dissolved in 400 parts of tetrahydrofuran, and an aqueous sodium hydroxide solution (NaOH: 12.4 parts, water: 100 parts) was added dropwise.
The solution was cooled to 5 ° C., and 25.2 parts (0.272 mol) of acrylic acid chloride was added dropwise over 40 minutes. Then, it stirred at 5 degreeC for 3 hours, and reaction was complete | finished.
The reaction solution was poured into water and extracted with toluene. This extract was repeatedly washed with an aqueous sodium bicarbonate solution and water. Thereafter, the solvent was removed from the toluene solution, and purification was performed by column chromatography (adsorption medium: silica gel, developing solvent: toluene). N-Hexane was added to the obtained colorless oil to precipitate crystals.
As described above, 80.73 parts of white crystals (yield == triarylamino group-substituted acrylate compound having a monofunctional charge transporting structure represented by the following structural formula (54) (compound corresponding to the exemplified compound No. 54)) 84.8%).

  The melting point of the obtained white crystals was 117.5 to 119.0 ° C. The elemental analysis values of the white crystals are shown in Table 3 below together with the calculated values.

-Production of electrophotographic photoreceptor-
Example 1
2. An undercoat layer coating solution, a charge generation layer coating solution, a charge transport layer coating solution, and a protective layer coating solution having the following composition are sequentially applied to a 30 mm diameter aluminum drum (JIS1050) and dried. A 5 μm undercoat layer, a 0.2 μm charge generation layer, a 20 μm charge transport layer, and a 5 μm protective layer were formed to produce a laminated photoreceptor (hereinafter referred to as “photoreceptor 1”).
The undercoat layer, charge generation layer, and charge transport layer were all formed by dip coating, but the protective layer was formed as follows.
The protective layer coating solution is spray-coated on the charge transport layer, and naturally dried for 20 minutes, and then irradiated with light under the conditions of a metal halide lamp: 160 W / cm, irradiation intensity: 500 mW / cm ² , and irradiation time: 60 seconds. Thus, the coating film was cured. Furthermore, a drying process for 20 minutes at 130 ° C. was added to form a 5 μm protective layer.
In addition, the coating liquid of the following composition was used for coating of an undercoat layer, a charge generation layer, a charge transport layer, and a protective layer, respectively.

(Undercoat layer coating solution)
Titanium oxide (CR-EL; manufactured by Ishihara Sangyo Co., Ltd.): 70 parts Alkyd resin [Beckolite M6401-50-S
(Solid content 50%, manufactured by Dainippon Ink and Chemicals, Inc.): 15 parts Melamine resin [Super Becamine L-121-60
(Solid content 60%), manufactured by Dainippon Ink & Chemicals, Inc.]: 10 parts 2-butanone: 100 parts

(Charge generation layer coating solution)
The above dispersion 1 was used.

テトラヒドロフラン： ８０部 (Charge transport layer coating solution)
Polycarbonate (Iupilon Z300: manufactured by Mitsubishi Gas Chemical Company): 10 parts Charge transport material represented by the following structural formula (C): 7 parts

Tetrahydrofuran: 80 parts

(Protective layer coating solution)
Trifunctional or higher functional radical polymerizable monomer having no charge transporting structure [
Trimethylolpropane triacrylate (KAYARAD;
TMPTA, manufactured by Nippon Kayaku Co., Ltd.), molecular weight: 296, number of functional groups: trifunctional,
Molecular weight / number of functional groups = 99]: 10 parts Radical polymerizable compound having a monofunctional charge transporting structure represented by the structural formula (54) (Exemplary Compound No. 54): 10 parts Photopolymerization initiator [1-hydroxy -Cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)]: 1 part Tetrahydrofuran: 100 parts

(Examples 2 to 12)
In Example 1, an electrophotographic photosensitive member was formed in the same manner as in Example 1 except that Dispersions 2 to 12 were used instead of Dispersion 1 used to form the charge generation layer (according to the dispersion number). Photoconductors 2 to 12).

(Comparative Examples 1-2)
In Example 1, an electrophotographic photosensitive member was formed in the same manner as in Example 1 except that the dispersions 13 to 14 were used instead of the dispersion 1 used for forming the charge generation layer (according to the dispersion number). Photoconductors 13 to 14).

(Example 13)
The photoreceptor 1 produced as described above was mounted on an image forming apparatus as shown in FIG. 5 and evaluated under the following conditions. The image exposure light source was a semiconductor laser of 780 nm (image writing by a polygon mirror), a scorotron charger was used as a charging member, a transfer belt was used as a transfer member, and a 660 nm LED was used as a charge removal light source.
Process conditions before the test were set as follows, and a chart with a writing rate of 6% (characters equivalent to 6% as an image area are written on the entire A4 surface) is continuously 20,000. Sheet printing was performed. The test environment is 23 ° C. and 55% RH.

Photoconductor charging potential (unexposed portion potential): -900V
Development bias: -650V (negative / positive development)
Surface potential of exposed part: -120V

As an evaluation, the photosensitive member charging potential and the exposed portion potential were measured before and after printing 20,000 images.
Initially, charging conditions and writing conditions (exposure amounts) were determined for each photoconductor so that the above charging potential and surface potential after exposure were obtained. After printing 20,000 sheets, the potential was measured while fixing the charging conditions and writing conditions determined in the initial state.
As a measuring method, a surface potential meter is mounted at the position of the developing portion shown in FIG. 5, and after charging the photosensitive member, solid writing is performed with the semiconductor laser, and the surface potential of the unexposed portion and the exposed portion potential at the development site are measured. It was measured. The results are shown in Table 4 below.

(Examples 14 to 24, Comparative Examples 3 to 4)
Evaluation was performed in the same manner as in Example 1 except that the photosensitive members 2 to 14 were used instead of the photosensitive member 1 used in Example 13. The results are shown in Table 4 below.

(Examples 25-36, Comparative Examples 5-6)
Evaluations were made in the same manner as in Examples 13 to 24 and Comparative Examples 3 to 4, except that the tests of Examples 25 to 36 and Comparative Examples 5 to 6 were performed in an environment of 10 ° C. and 15% RH. The results are shown in Table 5 below.

(Examples 37 to 48, Comparative Examples 7 to 8)
Evaluations were made in the same manner as in Examples 13 to 24 and Comparative Examples 3 to 4, except that the tests of Examples 37 to 48 and Comparative Examples 7 to 8 were performed in an environment of 30 ° C. and 90% RH. The results are shown in Table 6 below.

From the above evaluation results, when the photoreceptors 1 to 9 of the present invention are used, good characteristics are exhibited even after repeated use, and even if the environment fluctuates, the amount of change in the actual machine potential is small.
When the photoconductors 10 to 12 are used, the fluctuations in the actual machine potential are slightly larger in the repeated use and environmental variations than in the case where the photoconductors 1 to 9 are used.
On the other hand, when the photosensitive member 13 of the comparative example is used, the fluctuation of the actual internal potential is larger in repeated use and environmental fluctuations than when the photosensitive members 1 to 12 of the present invention are used.
Similarly, when the photosensitive member 14 of the comparative example is used, the fluctuation of the actual internal potential is larger in repeated use and environmental fluctuations than when the photosensitive members 1 to 12 of the present invention are used.
From the above evaluations, it was found that when the photoreceptor of the present invention was used, it had durability and stable electrostatic characteristics, and a stable image could be formed even after repeated use.

(Example 49)
A photoconductor was prepared in the same manner as in Example 8 except that the protective layer coating solution in Example 8 was changed to the one having the following composition (referred to as photoconductor 15).

(Protective layer coating solution)
Trifunctional or higher functional radical polymerizable monomer having no charge transporting structure [
Pentaerythritol tetraacrylate (SR-295;
Kayaku Sartomer), molecular weight: 352, number of functional groups: tetrafunctional,
Molecular weight / number of functional groups = 88]: 10 parts Radical polymerizable compound having a monofunctional charge transporting structure represented by the structural formula (54) (Exemplary Compound No. 54): 10 parts Photopolymerization initiator [1-hydroxy -Cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals)]: 1 part Tetrahydrofuran: 100 parts

(Example 50)
A photoconductor was prepared in the same manner as in Example 8 except that the protective layer coating solution in Example 8 was changed to the one having the following composition (referred to as photoconductor 16).

(Protective layer coating solution)
Trifunctional or higher functional radical polymerizable monomer having no charge transporting structure [
Caprolactone-modified dipentaerythritol hexaacrylate (KAYARAD DPCA-60; manufactured by Nippon Kayaku)
Molecular weight: 1263, number of functional groups: hexafunctional, molecular weight / number of functional groups = 211]: 10 parts Photopolymerization initiator [2,2-dimethoxy-1,2-diphenylethane-1-one (Irgacure 651; Ciba Specialty Chemicals) 1 part) Radical polymerizable compound having a monofunctional charge transport structure represented by the structural formula (54) (Exemplary Compound No. 54): 10 parts Tetrahydrofuran: 100 parts

(Example 51)
A photoconductor was prepared in the same manner as in Example 8 except that the protective layer coating solution in Example 8 was changed to one having the following composition (referred to as photoconductor 17).

光重合開始剤〔１−ヒドロキシ−シクロヘキシル−フェニル−ケトン
（イルガキュア１８４；チバ・スペシャルティ・ケミカルズ製）〕： １部
テトラヒドロフラン： １００部 (Protective layer coating solution)
Trifunctional or higher functional radical polymerizable monomer having no charge transporting structure [
Trimethylolpropane triacrylate (KAYARAD
TMPTA; manufactured by Nippon Kayaku Co., Ltd.), molecular weight: 296, number of functional groups: trifunctional,
Molecular weight / number of functional groups = 99]: 10 parts Radical polymerizable compound having a monofunctional charge transporting structure represented by the following structural formula (161) (compound corresponding to the exemplified compound No. 161): 10 parts

Photopolymerization initiator [1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184; manufactured by Ciba Specialty Chemicals)]: 1 part Tetrahydrofuran: 100 parts

(Example 52)
An electrophotographic photoconductor was prepared in the same manner as in Example 8 except that the charge transport layer coating solution in Example 8 was changed to the one having the following composition (referred to as photoconductor 18).

下記構造式（１３）で示される可塑剤： ０．５部

テトラヒドロフラン： １００部 (Charge transport layer coating solution)
Polymer charge transport material represented by the following structural formula (12) (weight average molecular weight: 125000): 15 parts

Plasticizer represented by the following structural formula (13): 0.5 part

Tetrahydrofuran: 100 parts

(Comparative Example 9)
A photoconductor was prepared in the same manner as in Example 8 except that the protective layer coating solution in Example 8 was changed to the one having the following composition (referred to as photoconductor 19).

光重合開始剤〔１−ヒドロキシ−シクロヘキシル−フェニル−ケトン
（イルガキュア１８４；チバ・スペシャルティ・ケミカルズ製）〕： １部
テトラヒドロフラン： １００部 (Protective layer coating solution)
Trifunctional or higher functional radical polymerizable monomer having no charge transporting structure [
Trimethylolpropane triacrylate (KAYARAD
TMPTA; manufactured by Nippon Kayaku Co., Ltd.), molecular weight: 296, number of functional groups: trifunctional,
Molecular weight / number of functional groups = 99]: 10 parts Radical polymerizable compound having a bifunctional charge transporting structure represented by the following structural formula (14): 10 parts

Photopolymerization initiator [1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184; manufactured by Ciba Specialty Chemicals)]: 1 part Tetrahydrofuran: 100 parts

(Comparative Example 10)
In Example 8, a photoconductor was prepared in the same manner as in Example 8 except that the charge transport layer had a thickness of 25 μm and no protective layer was provided (referred to as photoconductor 20).

(Example 53)
The photoconductor 8 produced as described above is mounted on an image forming apparatus as shown in FIG. 5, and an image exposure light source is a 780 nm semiconductor laser (image writing by a polygon mirror), a scorotron charger as a charging member, and a transfer member. A transfer belt was used, and a 660 nm LED was used as a static elimination light source. Process conditions before the test were set as follows, and a chart with a writing rate of 6% (characters equivalent to 6% as the image area are written on the entire A4 surface) was continuously 100,000 Sheet printing was performed. The test environment is 23 ° C. and 55% RH.
Charging conditions:
DC bias: -6.5 kV
Grid voltage: -930V

Subsequent white solid and halftone images were output and evaluated, and the presence or absence of background contamination and image density were confirmed (the test environment was 22 ° C.-55% RH).
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 ×. The above results are shown in Table 7 below.
Further, the film thickness of the photoconductor was measured at around 100,000 sheets. Measurements were made at 1 cm intervals in the longitudinal direction, and the average value was taken as the film thickness of the photoreceptor. The amount of wear was determined from the difference between the film thickness before the 100,000-sheet test and the film thickness after the 100,000-sheet test. The results are shown in Table 7 below.

(Examples 54-57, Comparative Examples 11-12)
The test was performed in the same manner as in Example 53 except that the photoconductor 8 used in Example 53 was changed to photoconductors 15 to 20. The results are shown in Table 7 below.

  From the above evaluation results, it was found that when the photoconductor of the present invention was used, the background smudge, the image density, and the wear amount were all good even after outputting 100,000 images.

(Example 58)
The photoconductor 8 produced as described above was mounted on a process cartridge as shown in FIG. 7 and evaluated by being mounted on an image forming apparatus as shown in FIG. Note that the image exposure light source is a semiconductor laser of 780 nm (image writing by a polygon mirror), and a charging member (photosensitive member and charging member) for close placement in which an insulating tape having a thickness of 50 μm is wound around both ends of a charging roller as a charging member Charging was performed under the following charging conditions using a gap between the surfaces of 50 μm). Further, a transfer belt was used as a transfer member, and a 660 nm LED (manufactured by Nichia Chemical) was used as a static elimination light source.
Process conditions before the test were set as follows, and a chart with a writing rate of 6% (characters equivalent to 6% as the image area are written on the entire A4 surface) was continuously 100,000 Sheet printing was performed.
Charging conditions:
DC bias: -900V
AC bias: 2.0 kV (Peak to peak), frequency: 2.0 kHz

After printing 100,000 sheets, white solids were output and evaluated at a black station, and the presence or absence of soiling was confirmed (the test environment was 22 ° C.-55% RH). 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 ×.
Further, before and after printing 100,000 sheets, an ISO / JIS-SCID image N1 (portrait) was output to evaluate the color color reproducibility. The above results are shown in Table 8 below.

(Examples 59-62, Comparative Examples 13-14)
A test was performed in the same manner as in Example 58 except that the photoconductor 8 used in Example 58 was changed to photoconductors 15 to 20. The results are shown in Table 8 below.

  From the above evaluation results, it was found that when the photoconductor of the present invention was used, the background stain and color reproducibility were all good even after outputting 100,000 images.

  As can be seen from the above evaluation results, according to the present invention, an electrophotographic photosensitive member capable of forming a stable image even when used repeatedly is obtained. By using this, for example, reversal development (negative / positive development) is obtained. 2), an image forming apparatus capable of high durability and stable operation without scumming and density reduction, and a process cartridge for an image forming apparatus having high durability and good handling can be configured.

It is sectional drawing which shows the structural example of the electrophotographic photoreceptor in this invention. It is sectional drawing which shows another structural example of the electrophotographic photoreceptor in this invention. It is sectional drawing which shows another example of a structure of the electrophotographic photoreceptor in this invention. It is sectional drawing which shows another example of a structure of the electrophotographic photoreceptor in this invention. 1 is a schematic diagram for explaining an image forming apparatus of the present invention. 1 is a schematic view for explaining a tandem type full-color image forming apparatus of the present invention. FIG. FIG. 2 is a schematic diagram for explaining a process cartridge for an image forming apparatus according to the present invention. It is a figure which shows the XD spectrum of the titanyl phthalocyanine powder (precursor) obtained by the synthesis example 1. It is a figure which shows the XD spectrum of the water paste dry powder obtained by the synthesis example 1. FIG. 4 is a diagram showing an XD spectrum of a titanyl phthalocyanine crystal (crystal 1) obtained in Synthesis Example 1. FIG. It is a figure which shows the XD spectrum of the titanyl phthalocyanine powder (precursor) obtained by the synthesis example 9. 6 is a diagram showing an XD spectrum of a titanyl phthalocyanine crystal (crystal 10) obtained in Synthesis Example 9. FIG. 6 is a diagram showing an example of an XD spectrum of a mixed powder (mass ratio 97: 3) of the precursor of Synthesis Example 1 and the crystal 13 of Comparative Synthesis Example 1. FIG. 6 is a diagram showing an example of an X-ray diffraction spectrum of a mixed powder (mass ratio 97: 3) of the precursor of Synthesis Example 10 and the crystal 13 of Comparative Synthesis Example 1. FIG.

Explanation of symbols

(Fig. 1-4)
31 Conductive Support 32 Intermediate Layer 34 Photosensitive Layer 35 Charge Blocking Layer 36 Moire Prevention Layer 37 Charge Generation Layer 38 Charge Transport Layer 39 Protective Layer (FIG. 5)
DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Static elimination lamp 3 Charging member 5 Image exposure part 6 Developing unit 8 Registration roller 9 Transfer paper 10 Transfer charger 11 Separation charger 12 Separation claw 14 Fur brush 15 Cleaning blade (FIG. 6)
16K, 16C, 16M, 16Y Photoconductor 17K, 17C, 17M, 17Y Charging member 18K, 18C, 18M, 18Y Image exposure member 19K, 19C, 19M, 19Y Developing member 20K, 20C, 20M, 20Y Cleaning member 21K, 21C, 21M, 21Y Transfer member 22 Transfer belt 23 Registration roller 24 Fixing member 25K, 25C, 25M, 25Y Image forming element 26 Transfer paper 27K, 27C, 27M, 27Y Static elimination member (FIG. 7)
DESCRIPTION OF SYMBOLS 101 Photoconductor 102 Charging member 103 Image exposure member 104 Developing member 105 Transfer paper 106 Transfer member 107 Cleaning member 108 Static elimination member

Claims (17)

In an electrophotographic photosensitive member formed by sequentially laminating at least a photosensitive layer and a protective layer on a conductive support,
The photosensitive layer has a maximum diffraction peak at 26.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray of CuKα (wavelength 1.542 mm), and 9.3 °. Also peaks at 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1 ° and 28.3 °. Resin cured product comprising a titanyl phthalocyanine crystal and a protective layer obtained by curing at least a trifunctional or higher functional radical polymerizable monomer having no charge transport structure and a monofunctional radical polymerizable compound having a charge transport structure An electrophotographic photosensitive member comprising:   2. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer has a laminated structure including a charge generation layer and a charge transport layer. The electron according to claim 1 or 2, wherein the monofunctional radically polymerizable compound having the charge transporting structure is at least one compound represented by the following general formula (1) or (2). Photoconductor.

[In General Formulas (1) and (2), R ₁ may have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Good aryl group, cyano group, nitro group, alkoxy group, —COOR ₇ (R ₇ has a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or a substituent. Aryl group), carbonyl halide group or CONR ₈ R ₉ (R ₈ and R ₉ are a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent) Or an aryl group which may have a substituent, which may be the same or different from each other), Ar ₁ and Ar ₂ each represent a substituted or unsubstituted arylene group, May be different. Ar ₃ and Ar ₄ represent a substituted or unsubstituted aryl group, and may be the same or different. X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group. Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether divalent group, or an alkyleneoxycarbonyl divalent group. m and n represent an integer of 0 to 3. ] 4. The electrophotographic photoreceptor according to claim 3, wherein the monofunctional radically polymerizable compound having a charge transporting structure is at least one compound represented by the following general formula (3).
The electrophotographic photosensitive member according to claim 1.

[In general formula (3), o, p and q are each an integer of 0 or 1, Ra represents a hydrogen atom or a methyl group, Rb and Rc are substituents other than a hydrogen atom, and an alkyl group having 1 to 6 carbon atoms. And a plurality of cases may be different. s and t represent an integer of 0 to 3. Za represents a single bond, a methylene group, an ethylene group, or a divalent group represented by the following formulas (4), (5), and (6). ]

  The electrophotographic photosensitive member according to claim 1, wherein the protective layer made of the cured resin is cured and formed by at least one of a heating unit and a light energy irradiation unit.   The titanyl phthalocyanine crystal contained in the photosensitive layer has a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα. 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, and a peak at 7.3 °. 2. A crystal obtained by subjecting a titanyl phthalocyanine crystal having no peak between 9.4 ° peaks and further having no peak at 26.3 ° to a crystal conversion treatment. The electrophotographic photosensitive member according to any one of 5.   The electrophotographic photosensitive member according to claim 6, wherein the crystal conversion treatment is a crystal conversion using an organic solvent.   8. The electrophotographic photosensitive member according to claim 7, wherein the organic solvent used for the crystal conversion treatment contains at least one solvent selected from a ketone solvent or an ether solvent.   The electrophotographic photosensitive member according to claim 6, wherein mechanical energy is applied during the crystal conversion treatment. As a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of the CuKα, it has a maximum diffraction peak at least 27.2 °, and further 9.4 °, 9.6 It has a major peak at °, 24.0 °, and has a peak at 7.3 ° as the lowest angled diffraction peak, with a peak between the peak at 7.3 ° and the peak at 9.4 ° And a titanyl phthalocyanine crystal that does not have a peak at 26.3 °,
An amorphous titanyl phthalocyanine having a maximum diffraction peak at 7.0 to 7.5 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα is 10. The electrophotographic photoreceptor according to claim 6, wherein the electrophotographic photoreceptor is obtained by crystal conversion with an organic solvent in the presence.   The electrophotographic photosensitive member according to claim 10, wherein the half-width of the diffraction peak at 7.0 to 7.5 ° of the amorphous titanyl phthalocyanine is 1 ° or more.   The organic solvent used for crystal conversion of the amorphous titanyl phthalocyanine includes at least one solvent selected from tetrahydrofuran, cyclohexanone, toluene, methylene chloride, carbon disulfide, orthodichlorobenzene, and 1,1,2-trichloroethane. The electrophotographic photosensitive member according to claim 10 or 11, wherein   13. The electrophotographic photosensitive member according to claim 10, wherein the amorphous titanyl phthalocyanine is synthesized without using a titanium halide.   The image forming apparatus comprising at least a charging unit, an exposure unit, a developing unit, a transfer unit, a fixing unit, and an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is the photosensitive member according to any one of claims 1 to 13. An image forming apparatus, comprising:   The image forming apparatus in which a plurality of image forming elements including at least a charging unit, an exposure unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member are arranged, wherein the electrophotographic photosensitive member is any one of claims 1 to 13. An image forming apparatus which is a photoconductor.   A cartridge in which the electrophotographic photosensitive member according to any one of claims 1 to 13 and at least one means selected from a charging means, an exposure means, a developing means, and a cleaning means are mounted, and the cartridge An image forming apparatus which is detachable from an apparatus main body.   14. The process cartridge for an image forming apparatus 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 claim 1. A process cartridge for an image forming apparatus, wherein the process cartridge is any one of the photoconductors.

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