JP5052218B2 - Electrophotographic photosensitive member, image forming apparatus, and process cartridge for image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member provided with a photosensitive layer containing a titanyl phthalocyanine crystal, an image forming apparatus, and a process cartridge for the image forming apparatus.

  Conventionally, in an image forming apparatus such as a digital copying machine or a digital printer, a titanyl phthalocyanine crystal having a high sensitivity characteristic with respect to long wavelength light of 600 to 800 nm emitted from a light source is known as an electrophotographic photosensitive member material. (For example, refer to Patent Document 1).

  An electrophotographic photosensitive member is usually formed by laminating a charge generation layer and a charge transport layer on a conductive support, and this charge generation layer is obtained by dispersing a dispersion in which titanyl phthalocyanine crystals are dispersed in an organic solvent. It is formed by applying and drying on the body.

  Electrophotographic photoreceptors using titanyl phthalocyanine crystals have high sensitivity to long-wavelength light from the light source, low residual potential, high chargeability, high acceptance potential, potential retention, and high potential stability. Need to be excellent. In addition, if the decrease in chargeability due to repeated use is large, the service life of the electrophotographic photosensitive member is shortened, so the decrease in chargeability due to repeated use must be small.

  The electrostatic characteristics of the electrophotographic photoreceptor using the titanyl phthalocyanine crystal are not only different depending on the crystal form of the titanyl phthalocyanine crystal, but also differ depending on the method for producing the titanyl phthalocyanine crystal.

  In the method for producing a titanyl phthalocyanine crystal described in Patent Document 1, as the first step, 1,2-dicyanobenzene and titanium tetrachloride are combined in the presence of an inert high-melting-point organic solvent (α-chloronaphthalene). Heat reaction. As a 2nd process, the amorphous titanyl phthalocyanine is obtained by carrying out the hot water process of the crude titanyl phthalocyanine obtained by making it heat-react in a 1st process. As the third step, the target titanyl phthalocyanine crystal can be obtained by heat-treating the amorphous titanyl phthalocyanine obtained in the second step with an organic solvent (for example, N-methylpyrrolidone).

  In this manufacturing method, since titanium tetrachloride is used, the produced titanyl phthalocyanine crystal contains chlorine as an impurity, and structural defect sites are introduced. Therefore, the electrophotographic photoreceptor is charged with repeated use. The decline is relatively large. Incidentally, it is difficult to remove chlorine taken into the titanyl phthalocyanine crystal.

  Thus, a method for producing a titanyl phthalocyanine crystal that does not use a metal halide such as titanium tetrachloride has also been proposed (see, for example, Patent Documents 2 to 4).

  In the method for producing a titanyl phthalocyanine crystal described in Patent Document 2, as a first step, 1,3-diiminoisoindoline and titanium tetrabutoxide are used in the presence of an aliphatic solvent (for example, α-chloronaphthalene). Heat reaction. As a second step, amorphous titanyl phthalocyanine is obtained by subjecting the dried crude titanyl phthalocyanine obtained by the heat reaction in the first step to a so-called acid paste treatment. As a third step, the target titanyl phthalocyanine crystal can be obtained by treating the dried amorphous titanyl phthalocyanine obtained in the second step with an organic solvent (for example, o-dichlorobenzene).

  In the method for producing a titanyl phthalocyanine crystal described in Patent Document 3, as the first step, phthalonitrile, titanium tetraalkoxide (for example, titanium tetrabutoxide), urea, and the presence of an organic solvent (for example, n-octanol) are used. The target titanyl phthalocyanine crystal can be obtained by heating under reaction.

In the method for producing a titanyl phthalocyanine crystal described in Patent Document 4, 1,3-diiminoisoindoline and titanium tetrabutoxide are heated and reacted in the presence of sulfolane. As a second step, amorphous titanyl phthalocyanine is obtained by subjecting the dried crude titanyl phthalocyanine obtained by the heat reaction in the first step to a so-called acid paste treatment. As the third step, the target titanyl phthalocyanine crystal can be obtained by treating the amorphous titanyl phthalocyanine obtained in the second step with an organic solvent (for example, tetrahydrofuran) in the presence of water.
Japanese Patent Publication No. 5-31137 Japanese Patent No. 2821765 JP-A-6-293769 JP 2001-19871 A

  However, the electrophotographic photosensitive member using the above conventional titanyl phthalocyanine crystal is not sufficiently stable in chargeability during repeated use, and is still excellent in chargeability stability during repeated use. Body, image forming apparatus, and process cartridge for image forming apparatus have been desired.

  The present invention has been made in view of the above, and an object of the present invention is to provide an electrophotographic photosensitive member, an image forming apparatus, and a process cartridge for the image forming apparatus that have excellent charging stability during repeated use. To do.

  In order to solve the above-described problems, the present invention is characterized by the following measures.

According to one aspect of the present invention, in an electrophotographic photosensitive member provided with a photosensitive layer containing at least a titanyl phthalocyanine crystal on a conductive support,
The titanyl phthalocyanine crystal has an irregular shape 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 1.542１．５) of CuKα. An organic solvent containing titanyl phthalocyanine in the presence of water and containing at least one organic solvent selected from tetrahydrofuran, cyclohexane, toluene, methylene chloride, carbon disulfide, orthodichlorobenzene, and 1,1,2-trichloroethane Obtained by crystal conversion by
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 at least 27.2 °, and further 9.4 ° and 9.6 °. , Having a main diffraction peak at 24.0 ° and a diffraction peak at 7.3 ° as the lowest angled diffraction peak, between the 7.3 ° peak and the 9.4 ° peak Using a titanyl phthalocyanine crystal that does not have a peak and does not have a diffraction peak at 26.3 °, a second crystal conversion was performed.
As a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray of CuKα (wavelength 1.542 mm), it has a maximum diffraction peak at least 26.2 °, and further 9.3 °, 10.5 ° , 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1 °, 28.3 °, titanyl phthalocyanine crystals having diffraction peaks. It is characterized by that.

  According to the present invention, the diffraction peak (± 0.2 °) of Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 波長) of CuKα has a maximum diffraction peak at least 27.2 °, and further 9.4. The main diffraction peak is at °, 9.6 °, and 24.0 °, and the diffraction peak at 7.3 ° is the lowest diffraction peak, and the peak at 7.3 ° is 9.4 ° A titanyl phthalocyanine crystal having no peak between the peaks at ° C and further having no diffraction peak at 26.3 ° is obtained by crystal conversion of the Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542Å) of CuKα. As a diffraction peak (± 0.2 °), it has a maximum diffraction peak at least 26.2 °, and further 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, Diffraction peaks at 16.1, 20.7, 23.2, 27.1, and 28.3 degrees To, by providing a photosensitive layer containing a titanyl phthalocyanine crystal can be provided repeatedly charged Stability excellent electrophotographic photosensitive member at the time of use, the image forming apparatus, a process cartridge for an image forming apparatus.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  The electrophotographic photosensitive member of this example is obtained by providing a photosensitive layer containing a titanyl phthalocyanine crystal described later on a conductive support.

  This titanyl phthalocyanine crystal has a first step of synthesizing crude titanyl phthalocyanine without using titanium halide, and a second step of producing amorphous titanyl phthalocyanine by so-called acid paste treatment of the crude titanyl phthalocyanine obtained in the first step. A third step of generating a titanyl phthalocyanine crystal as a precursor by subjecting the amorphous titanyl phthalocyanine obtained in the second step to crystal conversion with a second organic solvent in the presence of water. This is produced through a production process comprising the fourth step of producing a target titanyl phthalocyanine crystal by crystal-converting the dried precursor obtained in (1).

  The precursor obtained in the third step has a maximum diffraction peak at least 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to CuKα characteristic X-rays (wavelength 1.542 mm). Furthermore, it has major diffraction peaks at 9.4 °, 9.6 °, and 24.0 °, and has a diffraction peak at 7.3 ° as the lowest diffraction peak, and 7.3 °. It is a titanyl phthalocyanine crystal having no peak between the peak of 9.4 ° and the peak of 9.4 ° and further having no diffraction peak at 26.3 °.

  The titanyl phthalocyanine crystal obtained in the fourth step is obtained by crystal conversion of the precursor obtained in the third step, and has a Bragg angle 2θ diffraction peak with respect to the characteristic X-ray (wavelength 1.542 波長) of CuKα ( ± 0.2 °) having a maximum diffraction peak at least 26.2 °, and further 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 It is a titanyl phthalocyanine crystal having diffraction peaks at °, 20.7 °, 23.2 °, 27.1 °, and 28.3 °.

  In addition, although the manufacturing method of the titanyl phthalocyanine crystal | crystallization of a present Example consists of a 1st-4th process, as long as it passed through the 4th process, there is no restriction | limiting in the process, For example, the crude titanyl phthalocyanine obtained at a 1st process The amorphous titanyl phthalocyanine obtained in the second step and the precursor having the specific X-ray diffraction spectrum obtained in the third step may be obtained by another production method.

  Hereinafter, each step will be described in detail.

  In the first step, crude titanyl phthalocyanine is synthesized without using a titanium halide. As a method for synthesizing this crude titanyl phthalocyanine, for example, a known method described in Patent Document 3 or Patent Document 4 can be employed. That is, a crude titanyl phthalocyanine crystal can be obtained by heat-reacting a phthalonitrile and a metal alkoxide (for example, titanium tetraalkoxide) in the presence of urea and an organic solvent (for example, n-octanol). Alternatively, a crude titanyl phthalocyanine crystal can be obtained by heat-reacting 1,3-diiminoisoindoline and titanium tetrabutoxide in the presence of sulfolane.

  In this way, by synthesizing crude titanyl phthalocyanine without using titanium halide, it is possible to obtain a titanyl phthalocyanine crystal, which will be described later, with a low halogen element content, and to obtain an electrophotographic photoreceptor excellent in electrostatic characteristics. be able to.

  In the second step, the crude titanyl phthalocyanine obtained in the first step is treated with a so-called acid paste to produce amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine). Specifically, first, the crude titanyl phthalocyanine obtained in the first step is dissolved in 10 to 50 times (mass ratio) of concentrated sulfuric acid, and insoluble matters are removed by filtration or the like as necessary. Next, the crude titanyl phthalocyanine dissolved in concentrated sulfuric acid is slowly added to 10-50 times (mass ratio) of sufficiently cooled water or ice water with respect to concentrated sulfuric acid to precipitate amorphous titanyl phthalocyanine. Next, after filtering the precipitated amorphous titanyl phthalocyanine, washing with ion exchange water and filtration are repeated until the filtrate becomes neutral, and finally a water paste having a solid content concentration of about 5 to 15% by mass is obtained. .

  In the second step, it is important that the precipitated amorphous titanyl phthalocyanine is sufficiently washed with ion-exchanged water so as not to leave sulfate ions as much as possible. Specifically, it is preferable that the ion-exchanged water after washing exhibits physical property values described later.

  When the physical property value of ion-exchanged water after washing is expressed by pH, the pH of ion-exchanged water is preferably in the range of 6-8. This pH value can be measured with a commercially available pH meter.

  Further, when the physical property value of the ion-exchanged water after washing is expressed by specific conductivity, the specific conductivity of the ion-exchanged water is preferably 8 μS / cm or less, more preferably 5 μS / cm or less, and particularly preferably 3 μS / cm or less. . This specific conductivity can be measured with a commercially available electric conductivity meter.

  When the physical property value of ion-exchanged water after washing is within the above range, since the residual amount of sulfate ion in the water paste is small, a titanyl phthalocyanine crystal with low sulfate ion content can be obtained, and the electrostatic characteristics are improved. An excellent electrophotographic photoreceptor can be obtained. When the physical property value of the ion-exchanged water after washing deviates from the above range, in the electrophotographic photoreceptor described later, chargeability and photosensitivity are reduced.

  The amorphous titanyl phthalocyanine obtained in the second step has a maximum of at least 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 a diffraction peak. More preferably, the half width of the maximum diffraction peak is 1 ° or more. Moreover, it is preferable that the average particle diameter of a primary particle is 0.1 micrometer or less.

  In the third step, the amorphous titanyl phthalocyanine obtained in the second step is crystal-converted with a second organic solvent in the presence of water to produce a precursor. Specifically, the precursor is generated by subjecting the aqueous paste of amorphous titanyl phthalocyanine to crystal conversion using the second organic solvent without drying.

  The type of the second organic solvent is not limited as long as the desired precursor can be obtained, and in particular, tetrahydrofuran, toluene, methylene chloride, carbon disulfide, orthodichlorobenzene, and 1,1,2-trichloroethane can be used. preferable. These organic solvents may be used alone, two or more of these organic solvents may be mixed and used, or may be used by mixing with other solvents.

  The ratio (mass ratio) of the second organic solvent to the amorphous titanyl phthalocyanine is preferably 10 times or more, particularly preferably 30 times or more. By using a large amount of the organic solvent in this manner, crystal conversion can be performed in a short time, and impurities contained in the amorphous titanyl phthalocyanine can be removed. Therefore, a titanyl phthalocyanine crystal with little crystal transition and excellent crystal stability can be obtained, and an electrophotographic photoreceptor excellent in electrostatic characteristics can be obtained.

  In a 4th process, the target titanyl phthalocyanine crystal | crystallization is produced | generated by crystal-converting the precursor after drying obtained at the 3rd process.

  Crystal transformation of this precursor is performed by applying thermal energy such as crystal transformation by applying a mechanical energy such as a mechanical shearing force, crystal transformation by a first organic solvent, or heat treatment, for example. This is realized by crystal conversion by applying chemical energy such as crystal conversion by evaporation or precipitation after evaporation. Among these means, it is preferable to include at least one of crystal conversion using a first organic solvent and crystal conversion by applying a mechanical shearing force, and further including both. preferable. The means for crystal conversion of the precursor is not limited as long as the precursor can be crystal-converted to the target titanyl phthalocyanine crystal.

  Crystal transformation by the first organic solvent is realized, for example, by immersing the precursor in the first organic solvent and leaving it for a period of one day or longer. A mechanical shearing force may be applied to the precursor while the precursor is immersed in the first organic solvent. By using a mechanical shear force in combination, the crystal transformation of the precursor can be accelerated.

  As the first organic solvent, for example, one kind selected from an ether solvent and a ketone solvent can be used. 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. The type of the first organic solvent is not limited as long as the precursor can be crystal-converted into the target titanyl phthalocyanine crystal.

  In the fourth step, it is important that the first organic solvent does not contain water as much as possible. Since the precursor is in a stable state in the presence of water, if a large amount of water is contained in the first organic solvent, crystal conversion of the precursor is slow, which is not preferable. The precursor obtained in the third step is preferably dried before the fourth step.

  Crystal transformation by applying mechanical shearing force is realized by applying shearing force to the precursor using, for example, a mixer, a dry ball mill, or a mortar.

  Crystal transformation by heat treatment is realized by, for example, heat-treating the precursor at a high temperature of 100 ° C. or higher. Specifically, the precursor can be crystal-converted into a target titanyl phthalocyanine crystal by heat-treating the precursor in an electric furnace for several hours at a high temperature of 200 ° C. to 400 ° C. When the heating temperature is 400 ° C. or higher, decomposition of the molecular structure of the titanyl phthalocyanine crystal starts, which is not preferable. Further, the heat treatment is preferably performed in a light-shielded state at a high temperature in order to prevent decomposition of the molecular structure of the titanyl phthalocyanine crystal due to light stimulation. In addition, although heat processing may be performed under atmospheric pressure, you may carry out under reduced pressure (for example, 10 mmHg or less).

  Crystal transformation by evaporating and precipitating can be achieved by, for example, heating the precursor by physical vapor deposition (PVD), chemical vapor deposition (CVD), etc. This is realized by attaching a titanyl phthalocyanine crystal.

  The electrophotographic photosensitive member of this example is provided with a photosensitive layer containing a titanyl phthalocyanine crystal obtained by the manufacturing method including the first to fourth steps described above on a conductive support. FIG. 1 is a cross-sectional view showing an example of the structure of the electrophotographic photosensitive member of this embodiment. FIG. 2 is a cross-sectional view showing another example of the structure of the electrophotographic photosensitive member of this embodiment.

  As shown in FIGS. 1 and 2, the electrophotographic photosensitive member of this example has a single-layer photosensitive layer (33) mainly composed of a charge generation material and a charge transport material on a conductive support (31). It may be provided (see FIG. 1). On the conductive support (31), a charge generation layer (35) mainly composed of a charge generation material and a charge transport layer (37 composed mainly of a charge transport material) are provided. ) (See FIG. 2).

The conductive support (31) has a volume resistance of 10 ¹⁰ Ω · cm or less, for example, metal such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, indium oxide Metal oxide such as film or cylindrical plastic or paper coated by vapor deposition or sputtering, or a plate of aluminum, aluminum alloy, nickel, stainless steel, etc., and extrusion, drawing, etc. After forming the tube, it is possible to use a tube that has been surface-treated by cutting, superfinishing, polishing, or the like. Further, an endless nickel belt and an endless stainless steel belt disclosed in Japanese Patent Application Laid-Open No. 52-36016 can be used as the conductive support (31).

  Of these, a cylindrical support made of aluminum, which can be easily subjected to the anodic oxide film treatment, can be most preferably used. As used herein, aluminum includes both pure aluminum and aluminum alloys. Specifically, JIS 1000, 3000, and 6000 series aluminum or aluminum alloy is most suitable. Anodized films are made by anodizing various metals and alloys in an electrolyte solution. Among them, a film called anodized aluminum or aluminum alloy that has been anodized in an electrolyte solution is developed by reversal development (negative It is excellent in that it prevents point defects (black spots, background stains) that occur when used for 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% by mass, bath temperature: 5 to 25 ° C., current density: 1 to 4 A / dm ² , electrolysis voltage: 5 to 30 V, treatment time: about 5 to 60 minutes The processing is performed, but the present invention is not limited to this.

  Since the anodic oxide film produced in this way is porous and highly insulating, the surface is very unstable. For this reason, there is a change with time after fabrication, and the physical property value of the anodized film is likely to change. In order to avoid this, it is desirable to further seal the anodized film. Examples of the sealing treatment include a method of immersing the anodized film in an aqueous solution containing nickel fluoride and nickel acetate, a method of immersing the anodized film in boiling water, and a method of treating with pressurized steam. Among these, the method of immersing in the aqueous solution containing nickel acetate is the most preferable.

  Subsequent to the sealing treatment, the anodic oxide film is washed. The main purpose of this is to remove excess metal salts and the like attached by the sealing treatment. If this excessively remains on the surface of the conductive support (31) (anodized film), it not only adversely affects the quality of the coating film formed on the surface, but generally a low resistance component remains, so In addition, it may cause scumming. The cleaning may be performed once with pure water, but is usually performed at another stage. At this time, it is preferable that the final cleaning liquid is as clean (deionized) as possible. Moreover, it is desirable to perform physical rubbing cleaning with a contact member in one of the other cleaning processes. The film thickness of the anodized film formed as described above is preferably about 5 to 15 μm. If it is thinner than this, 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, generating residual potential and response of the electrophotographic photosensitive member. May decrease.

  In addition, the conductive support dispersed in an appropriate binder resin and coated on the conductive support can also be used as the conductive support (31) of this example. 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 coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.

  Furthermore, it is electrically conductive by a heat-shrinkable tube containing the conductive powder in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, and Teflon (registered trademark) on a suitable cylindrical substrate. Those provided with a conductive layer can also be used favorably as the conductive support (31) of this example.

  Next, the photosensitive layer will be described. As described above, the photosensitive layer includes a single-layer photosensitive layer (33) mainly composed of a charge generation material and a charge transport material (see FIG. 1), and charge generation mainly composed of the charge generation material. There are cases where the layer (35) and a charge transport layer (37) containing a charge transport material as a main component are included (see FIG. 2). Here, in order to simplify the description, the case where the latter charge generation layer (35) and the charge transport layer (37) are configured (see FIG. 2) will be described first.

  The charge generation layer (35) is a layer mainly composed of titanyl phthalocyanine crystal obtained by the above-described production method including the first to fourth steps, which is a charge generation material. The charge generation layer (35) is obtained by applying a dispersion obtained by dispersing titanyl phthalocyanine crystals obtained by the manufacturing method including the first to fourth steps in a third organic solvent on the conductive support (31). It is formed by applying to and drying.

  As a dispersion method for dispersing the titanyl phthalocyanine crystal in the third organic solvent, a general method can be used. For example, a ball mill, an attritor, a sand mill, a bead mill, or a method of dispersing with an ultrasonic wave can be used. .

  The third organic solvent is selected in consideration of wettability with the titanyl phthalocyanine crystal, dispersibility, and applicability of the dispersion liquid to the substrate, but as long as the crystal form of the titanyl phthalocyanine crystal can be stably maintained, There is no limit. As the third organic solvent, for example, isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin can be used. . In particular, good results can be obtained by using one selected from a ketone solvent, an ester solvent, and an ether solvent. In particular, ketone solvents are most effectively used. These organic solvents may be used alone or in combination.

  A binder resin may be added to the dispersion. By adding the binder resin, the crystal transition rate of the titanyl phthalocyanine crystal can be remarkably reduced, and the crystal form of the titanyl phthalocyanine crystal can be stably maintained. The binder resin is selected in consideration of the electrostatic characteristics of the electrophotographic photosensitive member and the applicability of the dispersion liquid to the substrate. The binder resin is polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly-N-vinylcarbazole, polyacrylamide, polyvinyl benzal, polyester. Phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, and polyvinyl pyrrolidone can be used. In particular, polyvinyl butyral can be used most effectively. The binder resin is subjected to dispersion in a state in which it is dissolved in a dispersion solvent in advance. The amount of the binder resin is preferably 0 to 500 parts by weight and more preferably 10 to 300 parts by weight with respect to 100 parts by weight of the titanyl phthalocyanine crystal.

  Further, water may be added to the dispersion. By adding water, the crystal transition rate of the titanyl phthalocyanine crystal can be remarkably reduced and the crystal form of the titanyl phthalocyanine crystal can be stably maintained, as in the case of the binder resin. In the case of adding water, distilled water or ion exchange water from which impurities are sufficiently removed is preferably used. However, if it is used in a large amount, problems such as a decrease in dispersibility, separation from an organic solvent, and precipitation of a binder resin occur. Therefore, depending on the type of organic solvent used, in the case of a hydrophobic solvent, the upper limit of water solubility of the organic solvent, and in the case of a hydrophilic solvent, 2 to 3 mass relative to the weight of the organic solvent. % Is the upper limit.

  As the coating method of the dispersion, methods such as dip coating, spray coating, beat coating, nozzle coating, spinner coating, ring coating, and the like can be used. The film thickness of the charge generation layer (35) is suitably about 0.01 to 5 μm, preferably 0.1 to 2 μm.

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

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

  Examples of the hole transport material include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazolines Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc., bisstilbene derivatives, enamine derivatives, etc. Other known materials may be mentioned. These charge transport materials may be used alone or in combination of two or more.

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

  The amount of the charge transport material is appropriately 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. The thickness of the charge transport layer is preferably about 5 to 100 μm. As the solvent used here, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used.

  For the charge transport layer (37), a polymer charge transport material having a function as a charge transport material and a function of a binder resin is also preferably used. The charge transport layer composed of these polymer charge transport materials is excellent in wear resistance. As the polymer charge transport material, known materials can be used, and in particular, a polycarbonate containing a triarylamine structure in the main chain and / or side chain is preferably used. Among these, the polymer charge transport materials represented by the formulas (I) to (X) are favorably used, and these are exemplified below and specific examples are shown.

（I）式
式中、Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立して置換もしくは無置換のアルキル基又はハロゲン原子、Ｒ_４は水素原子又は置換もしくは無置換のアルキル基、Ｒ_５、Ｒ_６は置換もしくは無置換のアリール基、ｏ、ｐ、ｑはそれぞれ独立して０〜４の整数、ｋ、ｊは組成を表し、０．１≦ｋ≦１、０≦ｊ≦０．９、ｎは繰り返し単位数を表し５〜５０００の整数である。Ｘは脂肪族の２価基、環状脂肪族の２価基、または下記一般式で表される２価基を表す。

(I) In the formula, R ₁ , R ₂ and R ₃ are each independently a substituted or unsubstituted alkyl group or 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 represents an aliphatic divalent group, a cycloaliphatic divalent group, or a divalent group represented by the following general formula.

Ｒ_１０１、Ｒ_１０２は各々独立して置換もしくは無置換のアルキル基、アリール基またはハロゲン原子を表す。ｌ、ｍは０〜４の整数、Ｙは単結合、炭素原子数１〜１２の直鎖状、分岐状もしくは環状のアルキレン基、−Ｏ−、−Ｓ−、−ＳＯ−、−ＳＯ_２−、−ＣＯ−、−ＣＯ−Ｏ−Ｚ−Ｏ−ＣＯ−（式中Ｚは脂肪族の２価基を表す。）、または、

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は１〜２０の整数、ｂは１〜２０００の整数、Ｒ_１０３、Ｒ_１０４は置換または無置換のアルキル基又はアリール基を表す）を表す。ここで、Ｒ_１０１とＲ_１０２、Ｒ_１０３とＲ_１０４は、それぞれ同一でも異なってもよい。）

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

（II）式
式中、Ｒ_７、Ｒ_８は置換もしくは無置換のアリール基、Ａｒ_１、Ａｒ_２、Ａｒ_３は同一又は異なるアリレン基を表す。 Ｘ、ｋ、ｊおよびｎは、（I）式の場合と同じである。

(II) In the formula, R ₇ and R ₈ represent a substituted or unsubstituted aryl group, and Ar _1, Ar ₂ , and Ar ₃ represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I).

（III）式
式中、Ｒ_９、Ｒ_１０は置換もしくは無置換のアリール基、Ａｒ_４、Ａｒ_５、Ａｒ_６は同一又は異なるアリレン基を表す。 Ｘ、ｋ、ｊおよびｎは、（I）式の場合と同じである。

(III) in _{Shikishiki, 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 case of the formula (I).

（IV）式
式中、Ｒ_１１、Ｒ_１２ は置換もしくは無置換のアリール基、Ａｒ_７、Ａｒ_８、Ａｒ_９は同一又は異なるアリレン基、ｐは１〜５の整数を表す。 Ｘ、ｋ、ｊおよびｎは、（I）式の場合と同じである。

In (IV) _{Shikishiki, R 11,} R ₁₂ is a substituted or unsubstituted aryl _{group, Ar 7, Ar 8, Ar} 9 are identical or different arylene group, p is an integer of 1-5. X, k, j and n are the same as in the case of the formula (I).

（V）式
式中、Ｒ_１３、Ｒ_１４は置換もしくは無置換のアリール基、Ａｒ_１０、Ａｒ_１１、Ａｒ_１２は同一又は異なるアリレン基、 Ｘ_１、Ｘ_２ は置換もしくは無置換のエチレン基、又は置換もしくは無置換のビニレン基を表す。 Ｘ、ｋ、ｊおよびｎは、（I）式の場合と同じである。

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

（VI）式
式中、Ｒ_１５、Ｒ_１６、Ｒ_１７、Ｒ_１８は置換もしくは無置換のアリール基、Ａｒ_１３、Ａｒ_１４、Ａｒ_１５、Ａｒ_１６は同一又は異なるアリレン基、 Ｙ_１、Ｙ_２、Ｙ_３は単結合、置換もしくは無置換のアルキレン基、置換もしくは無置換のシクロアルキレン基、置換もしくは無置換のアルキレンエーテル基、酸素原子、硫黄原子、ビニレン基を表し同一であっても異なってもよい。 Ｘ、ｋ、ｊおよびｎは、（I）式の場合と同じである。

(VI) In the formula, R ₁₅ , R ₁₆ , R ₁₇ , and R ₁₈ are substituted or unsubstituted aryl groups, Ar ₁₃ , Ar ₁₄ , Ar ₁₅ , and Ar ₁₆ are the same or different arylene groups, Y ₁ , 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 case of the formula (I).

（VII）式
式中、Ｒ_１９、Ｒ_２０ は水素原子、置換もしくは無置換のアリール基を表し、Ｒ_１９とＲ_２０は環を形成していてもよい。Ａｒ_１７、Ａｒ_１８、Ａｒ_１９は同一又は異なるアリレン基を表す。 Ｘ、ｋ、ｊおよびｎは、（I）式の場合と同じである。

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

（VIII）式
式中、Ｒ_２１は置換もしくは無置換のアリール基、Ａｒ_２０、Ａｒ_２１、Ａｒ_２２、Ａｒ_２３ は同一又は異なるアリレン基を表す。 Ｘ、ｋ、ｊおよびｎは、（I）式の場合と同じである。

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

（IX）式
式中、Ｒ_２２、Ｒ_２３、Ｒ_２４、Ｒ_２５は置換もしくは無置換のアリール基、Ａｒ_２４、Ａｒ_２５、Ａｒ_２６、Ａｒ_２７、Ａｒ_２８は同一又は異なるアリレン基を表す。 Ｘ、ｋ、ｊおよびｎは、（I）式の場合と同じである。

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

（X）式
式中、Ｒ_２６、Ｒ_２７は置換もしくは無置換のアリール基、Ａｒ_２９、Ａｒ_３０、Ａｒ_３１は同一又は異なるアリレン基を表す。 Ｘ、ｋ、ｊおよびｎは、（I）式の場合と同じである。

In (X) _{Shikishiki, R 26,} R ₂₇ is a substituted or unsubstituted aryl _{group, Ar 29, Ar 30, Ar} 31 independently represent an arylene group. X, k, j and n are the same as in the case of the formula (I).

  Further, as the polymer charge transport material used for the charge transport layer (37), in addition to the polymer charge transport material described above, a monomer or oligomer having an electron donating group may be used when forming the charge transport layer (37). In this state, a polymer having a two-dimensional or three-dimensional crosslinked structure is finally included by performing a curing reaction or a crosslinking reaction after film formation.

  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 electrophotographic photosensitive member is worn by repeated use, the electric field strength applied to the electrophotographic photosensitive member is increased accordingly. End up. As the electric field strength increases, the occurrence frequency of scumming increases. Therefore, the high abrasion resistance of the electrophotographic photosensitive member is advantageous against 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, high-speed response can be expected for an electrophotographic photoreceptor having a charge transport layer using a polymer charge transport material.

  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, and for example, JP-A-3-109406, JP-A 20000- It is also possible to use a cross-linked polymer having an electron donating group as disclosed in JP-A-206723 and JP-A No. 2001-34001. Also in this case, a material that can satisfy the above mobility can be used effectively.

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

  Next, the case where the photosensitive layer is composed of a single photosensitive layer (33) (see FIG. 1) will be described. The single-layer photosensitive layer (33) is composed mainly of a charge generation material and a charge transport material, and a dispersion liquid in which a charge generation material, a binder resin, and a charge transport material as necessary are dispersed in a solvent. It is formed by coating on a conductive support (31) and drying. Tetrahydrofuran, dioxane, dichloroethane, and cyclohexane can be used as the solvent. Further, as the binder resin, the binder resin mentioned in the charge transport layer (37) may be used as it is, or the binder resin mentioned in the charge generation layer (35) may be mixed and used. . Of course, the above-described polymer charge transport materials can also be used favorably. The amount of the charge generating material is preferably 5 to 40 parts by weight with respect to 100 parts by weight of the binder resin, and the amount of the charge transporting material is preferably 0 to 190 parts by weight, and more preferably 50 to 150 parts by weight. The thickness of the formed single-layer photosensitive layer (33) is suitably about 5 to 100 μm.

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

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

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

  In addition to the protective layer, fluorine resins such as polytetrafluoroethylene, silicon resins, and inorganic fillers such as titanium oxide, tin oxide, potassium titanate, and silica for the purpose of improving wear resistance, and organic What disperse | distributed the filler etc. can be added.

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

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

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

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

  In this embodiment, an intermediate layer can be provided between the photosensitive layer and the protective layer, and a binder resin is generally used as a main component in the intermediate layer. Examples of these resins include polyamide, alcohol-soluble nylon, water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol. As a method for forming the intermediate layer, a normal coating method is employed as described above. In addition, about 0.05-2 micrometers is suitable for the thickness of an intermediate | middle layer.

  FIG. 3 is a schematic diagram illustrating an example of the structure of the image forming apparatus according to the present exemplary embodiment. As shown in FIG. 3, the image forming apparatus according to the present embodiment has a uniform surface of the electrostatic latent image carrier (1) and the electrostatic latent image carrier (1), which are the above-described electrophotographic photosensitive members. A charging means (3) for charging the toner, an exposure means (5) for exposing the surface of the electrostatic latent image carrier (1) imagewise to form an electrostatic latent image, and a toner image to form a toner image. Developing means (6) for developing the electrostatic latent image using toner and transfer means (10) for transferring the toner image to a recording medium. Further, the image forming apparatus of this embodiment includes a cleaning unit (14, 15) and a cleaning unit (14, 15) for removing toner remaining on the electrostatic latent image carrier (electrophotographic photosensitive member) (1). Recycling means (not shown) for recycling the removed toner to the developing means (6), static elimination means (2) for removing static electricity from the electrostatic latent image carrier (electrophotographic photosensitive member) (1), and each means It comprises control means (not shown) for controlling.

  In FIG. 3, 8 is a registration roller, 9 is a transfer paper, 10 is a transfer charger, 11 is a separation charger, 12 is a separation claw, 14 is a fur brush, and 15 is a cleaning blade.

  As shown in FIG. 3, the electrophotographic photosensitive member (1) has a drum-like shape and contains the titanyl phthalocyanine crystal obtained by the manufacturing method including the first to fourth steps described above. It is equipped with. The shape of the electrophotographic photosensitive member (1) is not limited, and may be, for example, a sheet shape or an endless belt shape.

  The charging means (3) uniformly charges the surface of the electrophotographic photosensitive member (1).

  As the charging means (3), there is no limitation on the type of the realization means, for example, a contact charger equipped with a conductive or semiconductive roll, brush, film, rubber blade, corona discharge such as corotron, scorotron, etc. Can be used (including a proximity type non-contact charger having a gap of 100 μm or less between the surface of the electrophotographic photosensitive member (1) and the charger). These charging means (3) can be appropriately selected according to the purpose. For example, when quick charging is required, a scorotron type charger is used favorably, and compaction and electrophotography described later are possible. In a tandem type image forming apparatus using a plurality of photoconductors (1), a roller-shaped charger that generates less acid gas (NOx, SOx, etc.) and ozone is effectively used.

  The electric field strength applied to the electrophotographic photosensitive member (1) by the charging means (3) is preferably 20 to 60 V / μm, and more preferably 30 to 50 V / μm. The higher the electric field strength applied to the electrophotographic photosensitive member (1), the better the dot reproducibility. However, if the electric field strength is too high, dielectric breakdown of the electrophotographic photosensitive member (1), carrier adhesion during development, etc. Problems may occur. Therefore, the upper limit is approximately 60 V / μm or less, more preferably 50 V / μm or less.

  The electric field strength applied to the electrophotographic photosensitive member (1) by the charging means (3) is expressed by the following mathematical formula (1).

数式（１）中、ＳＶは、現像位置における静電潜像担持体の未露光部における表面電位（Ｖ）を表す。Ｇは、少なくとも感光層（電荷発生層及び電荷輸送層）を含む感光層の膜厚（μｍ）を表す。

In Equation (1), SV represents the surface potential (V) at 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).

  The exposure means (5) exposes the surface of the electrophotographic photosensitive member (1) uniformly charged by the charging means (3) imagewise based on an input signal corresponding to the document. The exposed portion of the surface of the electrophotographic photosensitive member (1) loses electric charge, so that an electrostatic latent image is formed on the surface of the electrophotographic photosensitive member (1).

  The exposure means (5) is not limited to the type of the realization means and can be appropriately selected according to the purpose. For example, a copying optical system, a rod lens array system, a laser optical system, a liquid crystal shutter optical system, Various exposure devices such as those can be used. In addition, you may employ | adopt the light back system which exposes imagewise from the back surface side of an electrophotographic photoreceptor (1).

  As the light source of the exposure means (5), 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. If there are a plurality of writing light sources, each of them only has to bear the writing area, and the upper limit is substantially “2400 dpi × number of writing light sources”. Among these light sources, light emitting diodes and semiconductor lasers have high irradiation energy and are used favorably.

  The developing means (6) has at least one developing sleeve, and forms a toner image by developing the electrostatic latent image formed by the exposure means (5) with toner.

  As the toner, for example, a toner having the same polarity as the charging polarity of the electrophotographic photosensitive member (1) can be used, and the electrostatic latent image can be 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.

  The transfer means (10) is a means for transferring the toner image developed by the developing means (6) to a recording medium (recording paper or the like). The transfer means (10) includes a method of directly transferring a toner image from the surface of the electrophotographic photosensitive member (1) to a recording medium, an intermediate transfer member, and after the toner image is primarily transferred onto the intermediate transfer member, the toner There is a method in which an image is secondarily transferred onto the recording medium. 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.

  As the transfer means (10), there is no limitation on the type of means for realizing it, and for example, a corona transfer device by corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, or an adhesive transfer device can be used. It is preferable to have at least a transfer charger that peels and charges the toner image formed on the body (1) to the recording medium side. As the transfer means (10), a transfer belt or a transfer roller can be used as the transfer charger, but 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, the current output from the power supply member (high voltage power supply) for supplying the charge to the transfer means (10) flows to the portion related to the transfer means (10) and does not flow into the electrophotographic photosensitive member (1). A method of controlling the current value to the electrophotographic photosensitive member (1) by subtracting the current is preferable.

  The transfer current is a current based on the amount of charge required to peel off the toner electrostatically attached to the electrophotographic photosensitive member (1) and transfer it to the transfer target (transfer paper or intermediate transfer member). is there. In order to avoid transfer defects such as transfer residue, it is sufficient to increase the transfer current. However, when using negative and positive development, the polarity of the electrophotographic photosensitive member (1) is opposite to that of the charged polarity. Charge is applied, and the electrostatic fatigue of the electrophotographic photosensitive member (1) becomes remarkable. The larger the transfer current, the more advantageous it is because an amount of charge exceeding the electrostatic adhesion force between the electrophotographic photosensitive member (1) and the toner can be given. However, when a certain threshold value is exceeded, the transfer means (10)-the electrophotographic photosensitive member ( 1), a discharge phenomenon occurs, resulting in scattering of a finely developed toner image. For this reason, the upper limit is a range in which this discharge phenomenon does not occur. This threshold value varies depending on the gap (distance) between the transfer means (10) and the electrophotographic photosensitive member (1), the material constituting both, and the discharge phenomenon is avoided by using approximately 200 μA or less. it can. Therefore, the upper limit value of the transfer current is about 200 μA.

  Depending on the surface potential of the electrophotographic photosensitive member (1) after transfer (the surface potential when entering the charge eliminating portion), the amount of charge passing through the electrophotographic photosensitive member (1) per cycle of image formation varies greatly. The larger this, the greater the influence on the electrostatic fatigue of the electrophotographic photoreceptor (1) in repeated use.

  This passing charge amount corresponds to the amount of charge flowing in the film thickness direction of the electrophotographic photosensitive member (1). As an operation of the electrophotographic photosensitive member (1) in the image forming apparatus, the charging means (3) is charged to a desired charging potential (in most cases, negatively charged), and is optically written based on an input signal corresponding to the original ( Exposure) is performed. At this time, photocarriers are generated in the portion where the optical writing is performed, and the surface charge is neutralized (potential decay). At this time, the amount of charge depending on the amount of generated photocarriers flows in the film thickness direction of the electrophotographic photosensitive member (1). On the other hand, the area where the optical writing is not performed (non-writing portion) proceeds to the discharging step by the discharging unit (2) through the developing step by the developing unit (6) and the transfer step by the transferring unit (10) (necessary). Accordingly, a cleaning process is performed by the cleaning means (14, 15) before that.) Here, when the surface potential of the electrophotographic photosensitive member (1) is close to the potential applied by the charging means (3) (excluding dark decay), the amount of light is almost the same as the region where optical writing has been performed. The amount of charge flows in the film thickness direction of the electrophotographic photosensitive member (1). Generally, since the current document has a low writing rate, this method means that most of the passing charge amount of the electrophotographic photosensitive member (1) in repeated use is the current flowing in the charge removal process (writing rate). Is 10%, the current flowing in the static elimination process occupies 90% of the total).

  This passing charge greatly affects the electrostatic characteristics of the electrophotographic photosensitive member (1), for example, causing deterioration of the material constituting the electrophotographic photosensitive member (1). As a result, the residual potential of the electrophotographic photosensitive member (1) is raised, depending on the amount of passing charge. When the residual potential of the electrophotographic photosensitive member (1) is increased, the negative and positive development used in this embodiment causes a serious problem because the image density is lowered. Therefore, in order to increase the life (high durability) of the electrophotographic photosensitive member (1) in the image forming apparatus, there is a problem of how to reduce the amount of charge passing through the electrophotographic photosensitive member (1). Exists.

  On the other hand, there is a concept of not performing the static neutralization, but if the charging means (3) does not have a large charger capability, the charging cannot be stabilized and a problem such as an afterimage may occur. As for the passing charge of the electrophotographic photosensitive member (1), the generated optical carrier is moved by light irradiation by the electric potential (the electric field generated thereby) charged on the surface of the electrophotographic photosensitive member (1). Caused by Therefore, if the surface potential of the electrophotographic photosensitive member (1) can be attenuated by means other than light, the amount of passing charge per one rotation (one cycle of image formation) of the electrophotographic photosensitive member (1) can be reduced. Can do.

  For this purpose, it is effective to adjust the passing charge amount of the electrophotographic photosensitive member (1) by adjusting the transfer bias in the transfer step. That is, the non-writing portion charged by the charging means (3) and not written by the exposure means (5) enters the transfer process in a state close to the charged potential except for the dark attenuation amount. At this time, the absolute value on the polarity side charged by the charging means (3) is reduced to 100 V or less, so that almost no photocarrier is generated even when the subsequent charge removal process is entered, and no passing charge is generated. This value is preferably closer to 0V.

  Further, by adjusting the transfer bias, a transfer bias is applied so that the surface potential of the electrophotographic photosensitive member (1) is charged to a polarity opposite to the charging polarity applied by the charging means (3), whereby an optical carrier is obtained. Is more desirable because it never occurs. However, under transfer conditions that charge to a reverse polarity, there may be cases where a large amount of transfer dust occurs or the main charge of the next image forming process (cycle) cannot catch up. In that case, since a problem such as an afterimage may occur, the absolute value of the reverse polarity is preferably 100 V or less.

  Adding the control as described above can effectively use the effect of the present invention as a remarkable effect.

  The neutralization means (2) neutralizes the electrophotographic photosensitive member (1) in preparation for new image formation.

  The neutralizing means (2) can be appropriately selected from known static eliminators, for example, fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light emitting diodes (LEDs), semiconductor lasers (LDs), All luminescent materials such as electroluminescence (EL) can be used. In particular, the use of a light source having a wavelength that is not absorbed by the metal oxide contained in the intermediate layer of the electrophotographic photosensitive member (1) makes the effect of this embodiment more remarkable and can be used advantageously. 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.

  The cleaning means (14, 15) removes the electrophotographic toner remaining on the electrophotographic photosensitive member (1) in preparation for new image formation.

  The cleaning means (14, 15) can be appropriately selected from known cleaners. For example, a magnetic brush cleaner, electrostatic brush cleaner, magnetic roller cleaner, blade cleaner, brush cleaner, web cleaner or the like is used. Can do.

  The recycling means (not shown) is a step of recycling the electrophotographic toner removed by the cleaning means (14, 15) to the developing means (6), and examples thereof include a known conveying means.

  The control means (not shown) controls the above-described means such as the charging means (3) and the exposure means (5).

  The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. For example, a device such as a sequencer or a computer can be used.

  FIG. 4 is a schematic view showing an example of the structure of the tandem type full-color image forming apparatus of this embodiment. In FIG. 4, a drum-shaped electrophotographic photosensitive member (1Y, 1M, 1C, 1K) includes a photosensitive layer containing titanyl phthalocyanine crystals obtained by the manufacturing method including the first to fourth steps described above. . Each configuration will be described below, but the same components as those in the image forming apparatus in FIG.

  These electrophotographic photoreceptors (1Y, 1M, 1C, 1K) can be rotated in the direction of the arrow in FIG. 4, and charging means (3Y, 3M, 3C, 3K), exposure means ( 5Y, 5M, 5C, 5K) and image forming elements (20Y, 20M, 20C, 20K) having developing means (6Y, 6M, 6C, 6K) having at least one developing sleeve are arranged.

  The charging means (3Y, 3M, 3C, 3K) is a charger constituting a charging device for uniformly charging the surface of the electrophotographic photosensitive member (1Y, 1M, 1C, 1K). From the surface side of the electrophotographic photosensitive member (1Y, 1M, 1C, 1K) between the charging means (3Y, 3M, 3C, 3K) and the developing means (6Y, 6M, 6C, 6K), exposure means (5Y 5M, 5C, 5K) is irradiated with the laser beam, and an electrostatic latent image is formed on the electrophotographic photosensitive member (1Y, 1M, 1C, 1K). Then, the four image forming elements (20Y, 20M, 20C, 20K) centering on the electrophotographic photosensitive members (1Y, 1M, 1C, 1K) are transfer transfer belts (22) as transfer material transfer means. Are juxtaposed along. The transfer conveyance belt (22) is electrophotographic between the developing means (6Y, 6M, 6C, 6K) and the cleaning means (15Y, 15M, 15C, 15K) of each image forming element (20Y, 20M, 20C, 20K). It is in contact with the photoreceptor (1Y, 1M, 1C, 1K). A transfer brush (10Y, 10M, 10C, 10K) for applying a transfer bias is disposed on the opposite side of the transfer conveyance belt (22) from the electrophotographic photoreceptor (1Y, 1M, 1C, 1K). Yes. Each image forming element (20Y, 20M, 20C, 20K) has the same configuration except that the color of the toner inside the developing device is different.

  In the full-color image forming apparatus having the configuration shown in FIG. 4, the image forming operation is performed as follows. First, the electrophotographic photosensitive member (1Y, 1M, 1C, 1K) rotates and the electrophotographic photosensitive member (1Y, 1M, 1C, 1K) is charged by the charging means (3Y, 3M, 3C, 3K). At this time, in order to form a high-definition latent image, the electric field strength applied to the electrophotographic photosensitive member (1Y, 1M, 1C, 1K) is 20 V / μm or more (60 V μm or less, preferably 50 V / μm or less). It is charged so that

  Next, writing is performed at a resolution of 1200 dpi or more (preferably 2400 dpi or more) by laser light with an exposure means (5Y, 5M, 5C, 5K) disposed outside the electrophotographic photoreceptor (1Y, 1M, 1C, 1K). And an electrostatic latent image corresponding to each color image to be produced is formed. As the writing light source, as described above, a light source suitable for any electrophotographic photosensitive member (1Y, 1M, 1C, 1K) is used. In this case as well, 2400 dpi writing is generally the upper limit for one writing light source.

  Next, the electrostatic latent image is developed by developing means (6Y, 6M, 6C, 6K) to form a toner image. Developing means (6Y, 6M, 6C, 6K) are developing means for developing with toners of Y (yellow), M (magenta), C (cyan), and K (black), respectively. 1Y, 1M, 1C, and 1K) are superimposed on the transfer paper (9). The transfer paper (9) is fed from a tray (not shown) by a paper feed roller (not shown), temporarily stopped by a pair of registration rollers (8), and electrophotographic photosensitive members (1Y, 1M, 1C, 1K). It is sent to the transfer conveyance belt (22) in synchronization with the image formation on the top. The transfer paper (9) held on the transfer conveyance belt (22) is conveyed, and each color toner at a contact position (hereinafter referred to as “transfer section”) with the electrophotographic photosensitive member (1Y, 1M, 1C, 1K). The image is transferred.

  The toner image on the electrophotographic photosensitive member (1Y, 1M, 1C, 1K) is transferred to the transfer brush (10Y, 10M, 10C, 10K) and the electrophotographic photosensitive member (1Y, 1M, 1C, 1K). Is transferred onto the transfer paper (9) by an electric field formed by the potential difference between the first transfer sheet and the transfer sheet. Then, the transfer paper (9) on which the four color toner images are passed through the four transfer portions is conveyed to the fixing device (24), where the toner is fixed, and is discharged to a paper discharge portion (not shown). Is done.

  In the fixing device (24) of this embodiment, the toner images transferred to the recording medium are fixed in a state where the toners of the respective colors are stacked. However, the toner images transferred to the recording medium for the respective color toners are fixed. May be fixed. The fixing device is not particularly limited and may be appropriately selected depending on the intended purpose, but a known heating and pressing unit is preferable. 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 this heating and pressing means is usually preferably 80 ° C to 200 ° C. In this embodiment, for example, a known optical fixing device may be used together with or instead of this fixing device, depending on the purpose.

  Further, residual toner that is not transferred by the transfer unit and remains on the electrophotographic photosensitive member (1Y, 1M, 1C, 1K) is collected by a cleaning unit (15Y, 15M, 15C, 15K).

  Subsequently, excess residual charges on the electrophotographic photosensitive members (1Y, 1M, 1C, 1K) are removed by the charge eliminating means (2Y, 2M, 2C, 2K). Thereafter, charging is performed uniformly again by the charging means (3Y, 3M, 3C, 3K), and the next image formation is performed.

  In the example of FIG. 4, the image forming elements (20Y, 20M, 20C, and 20K) are Y (yellow), M (magenta), and C (cyan) from the upstream side to the downstream side in the conveyance direction of the transfer paper (9). ), K (black) colors are arranged in this order, but the order is not limited to this order, and the color order is arbitrarily set. Further, when producing a black-only document, providing a mechanism for stopping the image forming elements (20Y, 20M, 20C) other than black can be used particularly effectively in this embodiment.

  Further, as described above, the surface of the electrophotographic photosensitive member (1Y, 1M, 1C, 1K) after transfer is charged to 100 V or less on the polar side charged by the charging means (3Y, 3M, 3C, 3K). It is preferable to charge the reverse polarity side, and it is particularly preferable to charge the reverse polarity side to 100 V or less. Thereby, the increase in the residual potential in the repeated use of the electrophotographic photosensitive member (1Y, 1M, 1C, 1K) can be reduced.

  Each means such as the charging means (3) and the exposure means (5) as described above may be fixedly incorporated in a copying apparatus, a facsimile, or a printer. May be incorporated. The process cartridge includes the electrophotographic photosensitive member (1), and additionally includes at least one of charging means (3), exposure means (5), developing means (6), and transfer means (10), This is an apparatus (part) that is detachable from the image forming apparatus.

  FIG. 5 is a schematic view showing an example of the structure of the process cartridge of this embodiment. Hereinafter, each component of the process cartridge will be described, but the same components as those of the image forming apparatus in FIG.

  The electrophotographic photoreceptor (1) is provided with a photosensitive layer containing a titanyl phthalocyanine crystal obtained by the production method comprising the first to fourth steps described above. A light source capable of writing is used for the exposure means (5), and an arbitrary charger is used for the charging means (3). In FIG. 5, 6 is a developing means having at least one developing sleeve, 9 is a transfer paper, 10 is a transferring means, 15 is a cleaning means, and 2 is a charge eliminating means.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not restrict | limited to the following Example, A various deformation | transformation and substitution are added to the following Example, without deviating from the scope of the present invention. be able to.

(Synthesis Example 1)
According to Patent Document 4, a precursor was synthesized, and the precursor was crystal-converted to produce a target titanyl phthalocyanine crystal.

[First step]
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. In Synthesis Example 1, no halogen-containing compound was used.

[Second step]
The crude titanyl phthalocyanine obtained in the first step was dissolved in 20 times (mass ratio) concentrated sulfuric acid. Next, this was dripped, stirring to 100 times amount (mass ratio) ice water, and amorphous titanyl phthalocyanine was deposited. Next, the precipitated amorphous titanyl phthalocyanine is filtered, and then repeatedly washed with ion-exchanged water (pH: 7.0, specific conductivity: 1.0 μS / cm) until the washing solution becomes neutral (after washing) The pH value of ion-exchanged water was 6.8, and the specific conductivity was 2.6 μS / cm), and a wet cake (water paste) was obtained. The solid content concentration of the wet cake was 15% by mass.

  6 is a diagram showing an example of an X-ray diffraction spectrum of the amorphous titanyl phthalocyanine obtained in Synthesis Example 1. FIG. The amorphous titanyl phthalocyanine used for the measurement of the X-ray diffraction spectrum was obtained by drying the water paste at 80 ° C. under reduced pressure (5 mmHg) for 2 days. The X-ray diffraction spectrum was measured using an X-ray diffraction apparatus (Rigaku Corporation: RINT1100) under the following conditions. In addition, since the measurement of the following X-ray diffraction spectrum was performed using the same apparatus on the same conditions, description of conditions is abbreviate | omitted in the measurement of the following X-ray diffraction spectra.

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 In the synthesis example 1, as is clear from FIG. 6, the diffraction peak (± 0.2) with respect to the characteristic X-ray (wavelength 1.542１．５) of CuKα, which is the target amorphous titanyl phthalocyanine. The maximum diffraction peak at 7.0 to 7.5 ° and the half-width of the maximum diffraction peak at 1 ° or more could be obtained.

[Third step]
40 g of the wet cake (water paste) obtained in the second step was put into 200 g of tetrahydrofuran as the second organic solvent, stirred for 4 hours, filtered and dried to obtain a precursor. Here, the ratio (mass ratio) of the second organic solvent to the amorphous titanyl phthalocyanine was 33 times.

  FIG. 7 is a diagram showing an example of an X-ray diffraction spectrum of the precursor obtained in Synthesis Example 1. In the synthesis example 1, as is clear from FIG. 7, 27.2 as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542Å) of the target precursor, CuKα. Has a maximum diffraction peak at °, further has main diffraction peaks at 9.4 °, 9.6 °, and 24.0 °, and has a diffraction peak at 7.3 ° as the lowest diffraction peak. Thus, a titanyl phthalocyanine crystal having no peak between the peak at 7.3 ° and the peak at 9.4 ° and further having no diffraction peak at 26.3 ° could be obtained.

[Fourth step]
The precursor obtained in the third step was crystal-converted with a first organic solvent described later to obtain the target titanyl phthalocyanine crystal.

  That is, 40 g of the precursor synthesized in the third step and 400 g of 2-butanone as the first organic solvent are put into a ball mill pot with an inner diameter of 150 mm together with 3.5 kg of zirconia balls with a diameter of 2 mm and milled for 24 hours. went. After the treatment with the first organic solvent, the filtered product was vacuum-dried at 100 ° for 1 day to obtain the target titanyl phthalocyanine crystal.

  FIG. 8 is a diagram showing an example of an X-ray diffraction spectrum of a titanyl phthalocyanine crystal obtained by crystal conversion of the precursor of Synthesis Example 1. In the synthesis example 1, as is clear from FIG. 8, as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542１．５) of CuKα, which is the target titanyl phthalocyanine crystal, 26. It has a maximum diffraction peak at 2 ° and is further 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °. And titanyl phthalocyanine crystals having diffraction peaks at 27.1 ° and 28.3 ° were obtained (this is referred to as crystal 1).

(Synthesis Examples 2 to 7)
In Synthesis Examples 2 to 7, in the third step, titanyl phthalocyanine crystals were obtained in the same manner as in Synthesis Example 1 except that instead of tetrahydrofuran, the organic solvent described in Table 1 was used as the second organic solvent. Synthesized.

表１に記載の第２の有機溶媒を用いることで得られた前駆体のＸ線回折スペクトルは、それぞれ、合成例１の前駆体のＸ線回折スペクトル（図７参照）と同様のものであった。つまり、合成例２〜７では、目的の前駆体である、ＣｕＫαの特性Ｘ線（波長１．５４２Å）に対するブラッグ角２θの回折ピーク（±０．２°）として、２７．２°に最大回折ピークを有し、更に９．４°、９．６°、２４．０°に主要な回折ピークを有し、かつ最も低角側の回折ピークとして７．３°に回折ピークを有し、７．３°のピークと９．４°のピークの間にピークを有さず、更に２６．３°に回折ピークを有さないチタニルフタロシアニン結晶を得ることができた。

The X-ray diffraction spectrum of the precursor obtained by using the second organic solvent described in Table 1 was the same as the X-ray diffraction spectrum of the precursor of Synthesis Example 1 (see FIG. 7). It was. That is, in Synthesis Examples 2 to 7, the maximum diffraction at 27.2 ° as the diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542Å) of CuKα that is the target precursor. Having a major diffraction peak at 9.4 °, 9.6 °, 24.0 °, and a diffraction peak at 7.3 ° as the lowest angled diffraction peak, A titanyl phthalocyanine crystal having no peak between the peak at 3 ° and the peak at 9.4 ° and further having no diffraction peak at 26.3 ° could be obtained.

  Further, the X-ray diffraction spectra of the titanyl phthalocyanine crystal obtained by crystal conversion of the precursors of Synthesis Examples 2 to 7 are the X-ray diffraction spectrum of the crystal 1 finally obtained in Synthesis Example 1 (see FIG. 8), respectively. It was similar. That is, in Synthesis Examples 2 to 7, the diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542Å) of CuKα, which is the target titanyl phthalocyanine crystal, is 26.2 ° maximum. It has diffraction peaks and is further 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1. A titanyl phthalocyanine crystal having a diffraction peak at ° and 28.3 ° could be obtained (referred to as crystals 2 to 7).

(Synthesis Example 8)
In Synthesis Example 8, in the fourth step, crystal conversion with the first organic solvent was performed as follows to obtain a titanyl phthalocyanine crystal.

  40 g of the precursor synthesized in the third step of Synthesis Example 1 was immersed in 400 g of tetrahydrofuran as the first organic solvent for 1 week in a dark place. One week later, the titanyl phthalocyanine crystal separated by filtration was vacuum-dried at 100 ° for 1 day to obtain the desired titanyl phthalocyanine crystal.

  The X-ray diffraction spectrum of the titanyl phthalocyanine crystal finally obtained in Synthesis Example 8 was the same as the X-ray diffraction spectrum of the crystal 1 finally obtained in Synthesis Example 1 (see FIG. 8). That is, in Synthesis Example 8, the diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 波長) of CuKα, which is the target titanyl phthalocyanine crystal, is a maximum diffraction peak at 26.2 °. 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1 °, A titanyl phthalocyanine crystal having a diffraction peak at 28.3 ° could be obtained (referred to as crystal 8).

(Synthesis Example 9)
In Synthesis Example 9, in the fourth step, as a means for crystal conversion of the precursor, instead of crystal conversion using an organic solvent, crystal conversion by applying mechanical shear force was used. In the same manner as in Synthesis Example 1, a titanyl phthalocyanine crystal was synthesized.

  That is, in Synthesis Example 9, 40 g of the precursor of Synthesis Example 1 was placed in a ball mill pot with a diameter of 150 mm together with 3.5 kg of zirconia balls with a diameter of 2 mm, and milled for 48 hours. After milling, it was fractionated from zirconia balls to obtain the desired titanyl phthalocyanine crystal.

  The X-ray diffraction spectrum of the titanyl phthalocyanine crystal finally obtained in Synthesis Example 9 was the same as the X-ray diffraction spectrum of the crystal 1 finally obtained in Synthesis Example 1 (see FIG. 8). That is, in Synthesis Example 9, the diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542Å) of CuKα, which is the target titanyl phthalocyanine crystal, is a maximum diffraction peak at 26.2 °. 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1 °, A titanyl phthalocyanine crystal having a diffraction peak at 28.3 ° could be obtained (referred to as crystal 9).

(Comparative Synthesis Example 1)
In Comparative Synthesis Example 1, a titanyl phthalocyanine crystal was synthesized in the same manner as in Synthesis Example 1 except that 2-butanone was used instead of tetrahydrofuran as the second organic solvent in the third step.

  FIG. 9 is a diagram showing an example of an X-ray diffraction spectrum of the precursor obtained in Comparative Synthesis Example 1. As is clear from FIG. 9, the precursor obtained in Comparative Synthesis Example 1 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). Has a diffraction peak at 7.5 ° as the lowest diffraction peak.

  To the precursor obtained in Synthesis Example 1 and the precursor obtained in Comparative Synthesis Example 1, 3% by mass of the one prepared in the same manner as the pigment crystal described in JP-A No. 61-239248, Mixing in a mortar gave a mixed powder. Each was measured for X-ray diffraction spectra under the same conditions as above.

  The X-ray diffraction spectrum of the powder containing the precursor of Synthesis Example 1 is shown in FIG. 10, and the X-ray diffraction spectrum of the powder containing the precursor of Comparative Synthesis Example 1 is shown in FIG. In the spectrum of FIG. 10, 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. 11, the low angle side peak exists only at 7.5 °, which is clearly different from the spectrum of FIG.

  12 is a diagram showing an example of an X-ray diffraction spectrum of a titanyl phthalocyanine crystal finally obtained in Comparative Synthesis Example 1. FIG. As is clear from FIG. 12, the titanyl phthalocyanine crystal finally obtained in Comparative Synthesis Example 1 has a Bragg angle 2θ (± 0.2 °) diffraction peak with respect to the Cu—Kα ray (wavelength 1.542１．５), It has a maximum diffraction peak at 26.2 ° and is further 9.3 °, 10.5 °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23. It has diffraction peaks at 2 °, 27.1 °, and 28.3 ° (this is referred to as crystal 10). That is, the crystal 10 finally obtained in Comparative Synthesis Example 1 was the same as the crystals 1-9 finally obtained in Synthesis Examples 1-9 as the X-ray diffraction spectrum.

  Thus, the production method of the titanyl phthalocyanine crystal of Comparative Synthesis Example 1 has a diffraction peak on the lowest angle side of the Bragg angle 2θ (± 0.2 °) with respect to the Cu—Kα ray (wavelength 1.542Å) as a precursor. The method differs from the method for producing titanyl phthalocyanine crystals of Synthesis Examples 1 to 9 in that a titanyl phthalocyanine crystal having a diffraction peak at 7.5 ° is used.

(Comparative Synthesis Example 2)
A titanyl phthalocyanine crystal was synthesized according to Production Example 1 of Patent Document 1.

  Specifically, 97.5 g of phthalodinitrile was added to 750 ml of α-chloronaphthalene, and then 22 ml of titanium tetrachloride was 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 obtained cake of crude titanyl phthalocyanine was washed with 300 ml of α-chloronaphthalene and then with 300 ml of methanol at room temperature, and further washed with 800 ml of methanol for 1 hour with hot washing three times, and the resulting cake was added to 700 ml of water. Suspended and heat washed for 2 hours. 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 subjected to hot washing 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).

  It was confirmed that the X-ray diffraction spectrum of the crystal 11 finally obtained in Comparative Synthesis Example 2 was the same as that shown in FIG.

  Thus, the method for producing a titanyl phthalocyanine crystal of Comparative Synthesis Example 2 is a synthesis example in that it does not use a step of crystal conversion of a precursor having a specific X-ray diffraction spectrum, and uses titanium halide as a raw material. It differs from the manufacturing method of 1-9 titanyl phthalocyanine crystals.

(Comparative Synthesis Example 3)
A titanyl phthalocyanine crystal was synthesized according to Production Example 4 of Patent Document 1.

  Specifically, 46 g of phthalodinitrile was charged in 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, and then gradually heated to 220 ° C. And stirred for 2 hours. 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 at 80 ° C for 1 day to obtain titanyl phthalocyanine crystals 12).

  It was confirmed that the X-ray diffraction spectrum of the crystal 12 finally obtained in Comparative Synthesis Example 3 was the same as that shown in FIG.

  As described above, the method for producing a titanyl phthalocyanine crystal of Comparative Synthesis Example 3 is a synthesis example in that a step of crystal conversion of a precursor having a specific X-ray diffraction spectrum is not used and a titanium halide is used as a raw material. It differs from the manufacturing method of 1-9 titanyl phthalocyanine crystals.

(Examples 1-9, Comparative Examples 1-3)
Using the titanyl phthalocyanine crystals 1 to 12 produced as described above, electrophotographic photoreceptors 1 to 12 were produced as follows, and the electrostatic characteristics of the electrophotographic photoreceptors 1 to 12 were evaluated.

[Preparation of dispersion]
Dispersions 1 to 12 were prepared by mixing the titanyl phthalocyanine crystals shown in Table 2 with a binder resin and a solvent in the following proportions and dispersing them with zirconia balls having a diameter of 0.5 mm. A bead mill disperser (VMA-GETZMANN GMBH: DISPERMAT SL) was used for the preparation of the dispersion. After dispersing for 300 minutes at a rotor rotation speed of 3000 rpm, 2060 parts by weight of 2-butanone was added to the bead mill disperser in order to take out the dispersion from the bead mill disperser to prepare dispersions 1-12.

Titanyl phthalocyanine crystal (see Table 2) 48 parts by weight Polyvinyl butyral (manufactured by Sekisui Chemical: BX-1) 32 parts by weight 2-butanone 720 parts by weight

このように作製した分散液１〜１２をそれぞれ乾燥させ、その乾燥体のＸ線回折スペクトルを測定したところ、分散前のチタニルフタロシアニン結晶のＸ線回折スペクトル（図８、図１２等参照）と同様のものであった。したがって、本実施例の分散液によれば、本実施例のチタニルフタロシアニン結晶を安定状態で分散できることを確認できた。

Each of the dispersions 1 to 12 thus prepared was dried, and the X-ray diffraction spectrum of the dried product was measured. The same as the X-ray diffraction spectrum of the titanyl phthalocyanine crystal before dispersion (see FIG. 8, FIG. 12, etc.) It was a thing. Therefore, according to the dispersion liquid of this example, it was confirmed that the titanyl phthalocyanine crystal of this example could be dispersed in a stable state.

  Moreover, the dispersion liquids 1-12 produced in this way were put into the test tube for a sedimentation test, the stationary storage was performed for 3 days, and the state of the dispersion liquid was observed. As a result, no settling of particles was observed in any of the dispersions, and it was confirmed that the dispersion stability of the dispersion was high.

  Moreover, after stirring the dispersion liquid 1-12 produced in this way at room temperature using a stirrer for 1 month, when each of the dispersion liquids 1-12 was dried and the X-ray-diffraction spectrum of the dried body was measured, It was the same as the X-ray diffraction spectrum of the titanyl phthalocyanine crystal before dispersion (see FIG. 8, FIG. 12, etc.). Therefore, according to the dispersion liquid of this example, it was confirmed that the titanyl phthalocyanine crystal of this example could be dispersed in a stable state.

[Production of electrophotographic photosensitive member]
Using the dispersions 1 to 12 thus prepared, electrophotographic photoreceptors 1 to 12 were prepared, respectively. That is, an undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following composition were sequentially applied and dried on an aluminum plate (JIS 1050) having a thickness of 1 mm. Electrophotographic photosensitive members 1 to 12 each comprising a pulling layer, a 0.2 μm charge generation layer, and a 25 μm charge transport layer were formed.
(Undercoat layer coating solution)
Titanium oxide (Ishihara Sangyo Co., Ltd .: CR-EL) 70 parts by weight Alkyd resin (Dainippon Ink Chemical Co., Ltd .:
Beckolite M6401-50-S, (solid content 50 mass%)) 15 parts by weight Melamine resin (Dainippon Ink & Chemicals, Inc .:
Superbecamine L-121-60, (solid content 60% by mass)) 10 parts by weight 2-butanone 100 parts by weight (charge generation layer coating solution)
The above dispersions 1 to 12 were used, respectively.
(Charge transport layer coating solution)
Polycarbonate (Mitsubishi Gas Chemical Co., Ltd .: Iupilon Z300) 10 parts by weight Tetrahydrofuran 80 parts by weight 7 parts by weight of charge transport material having the following structural formula

［電子写真感光体の静電特性の評価１］
このように作製した電子写真感光体１、８、９〜１２を、静電複写紙試験装置（川口電機製、ＥＰＡ−８１００）を用いて、次のように評価した。

[Evaluation of electrostatic characteristics of electrophotographic photosensitive member 1]
The electrophotographic photoreceptors 1, 8 and 9 to 12 thus produced were evaluated as follows using an electrostatic copying paper test apparatus (manufactured by Kawaguchi Electric, EPA-8100).

First, corona charging is performed at a discharge voltage of −6.3 kV for 20 seconds, and then dark decay is performed for 20 seconds. Next, 5 μW / cm ² light (tungsten lamp light passing through a band pass filter of 780 nm) was exposed for 20 seconds to attenuate the light.

  The surface potential (V20) after 20 seconds of charging and the surface potential (V40) after 20 seconds of dark decay were measured, and the ratio (V40 / V20) was determined. Further, the time during which the surface potential was attenuated by light from V40 to 1/10 of V40 by exposure was determined, and the photosensitivity was determined from the product of the exposure amount. These results are shown in Table 3.

  Further, after repeating the above charging and exposure for 30 minutes, the same measurement was performed to obtain the characteristics after fatigue. The results are shown in Table 3.

表３から明らかなように、実施例の電子写真感光体１、８、９では、疲労後の帯電性が良好であることが確認できた。これに対し、比較例の電子写真感光体１０〜１２では、疲労後の帯電性が良くなかった。

As is clear from Table 3, it was confirmed that the electrophotographic photoreceptors 1, 8, and 9 of the examples had good chargeability after fatigue. On the other hand, in the electrophotographic photoreceptors 10 to 12 of the comparative example, the chargeability after fatigue was not good.

  When the electrophotographic photoreceptors 1, 8, and 9 of the examples are compared with the electrophotographic photoreceptor 10 of the comparative example, they are manufactured in the same manner except that the type of titanyl phthalocyanine crystal is different. Therefore, when these titanyl phthalocyanine crystals are compared, the crystals 1, 8, 9 used in Examples 1, 8, and 9 and the crystal 10 used in Comparative Example 1 are the same as the X-ray diffraction spectrum. There are different X-ray diffraction spectra of the precursors.

  Therefore, even if it is the same titanyl phthalocyanine crystal as the X-ray diffraction spectrum, by using a titanyl phthalocyanine crystal obtained by crystallizing a precursor having a specific X-ray diffraction spectrum, the stability of chargeability during repeated use is improved. It was found that an electrophotographic photoreceptor excellent in the above can be provided. That is, even if it was the same titanyl phthalocyanine crystal as the X-ray diffraction spectrum, it was confirmed that the titanyl phthalocyanine crystal obtained by crystal conversion of a precursor having a specific X-ray diffraction spectrum was excellent in crystal stability. .

(Examples 10 to 18, Comparative Examples 4 to 6)
[Evaluation of electrostatic characteristics of electrophotographic photosensitive member 2]
In addition, the electrophotographic photosensitive members 1 to 12 thus manufactured are mounted on an image forming apparatus as shown in FIG. 3, and the surface potentials of the exposed and non-exposed portions of the electrophotographic photosensitive members 1 to 12 are initially set, and By measuring after printing 20,000 sheets, the electrostatic characteristics of the electrophotographic photoreceptors 1 to 12 were evaluated.

  A scorotron charger as the charging means (3), a 780 nm semiconductor laser (image writing by a polygon mirror) as the light source of the exposure means (5), and a chart of 6% as the writing ratio of the exposure means (5) (with respect to the entire surface of A4) A character equivalent to 6% as an image area is written on the average), a transfer belt as the transfer means (10), and a 660 nm LED as the light source of the charge removal means (2). The test environment is 23 ° C. and 55% RH. The charging conditions and the exposure conditions (exposure amounts) were set for each of the electrophotographic photoreceptors 1 to 12 so that the following process conditions were satisfied in the initial state.

Surface potential of unexposed area: −900V
Development bias: -650V (negative / positive development)
Surface potential of exposed area: -120V
The surface potentials of the electrophotographic photosensitive members 1 to 12 were measured by mounting a surface potential meter at the installation position of the developing means 6 to measure the surface potentials of the unexposed and exposed areas during development after charging and exposure. . The results are shown in Table 4.

（実施例１９〜２７、比較例７〜９）
実施例１０〜１８、比較例４〜６の試験を、１０℃、１５％ＲＨの環境下で行った以外は、実施例１０〜１８、比較例４〜６と同様に評価を行った。結果を表５に示す。

(Examples 19 to 27, Comparative Examples 7 to 9)
Evaluations were made in the same manner as in Examples 10-18 and Comparative Examples 4-6, except that the tests of Examples 10-18 and Comparative Examples 4-6 were conducted in an environment of 10 ° C. and 15% RH. The results are shown in Table 5.

（実施例２８〜３６、比較例１０〜１２）
実施例１０〜１８、比較例４〜６の試験を、３０℃、９０％ＲＨの環境下で行った以外は、実施例１０〜１８、比較例４〜６と同様に評価を行った。結果を表６に示す。

(Examples 28-36, Comparative Examples 10-12)
Evaluations were made in the same manner as in Examples 10-18 and Comparative Examples 4-6, except that the tests of Examples 10-18 and Comparative Examples 4-6 were performed in an environment of 30 ° C. and 90% RH. The results are shown in Table 6.

表４、５、６から明らかなように、実施例の電子写真感光体１〜９では、疲労後の帯電性が良好であることが確認できた。これに対し、比較例の電子写真感光体１０〜１２では、疲労後の帯電性が良くなかった。また、環境が変動した場合でも、実施例の電子写真感光体１〜９は、比較例の電子写真感光体１０〜１２と比較して、変動幅が小さかった。

As is clear from Tables 4, 5, and 6, it was confirmed that the electrophotographic photoreceptors 1 to 9 of the examples had good chargeability after fatigue. On the other hand, in the electrophotographic photoreceptors 10 to 12 of the comparative example, the chargeability after fatigue was not good. Moreover, even when the environment fluctuated, the electrophotographic photoreceptors 1 to 9 of the examples had a smaller fluctuation range than the electrophotographic photoreceptors 10 to 12 of the comparative example.

  When the electrophotographic photoreceptors 1 to 9 of the example and the electrophotographic photoreceptor 10 of the comparative example are compared, they are manufactured in the same manner except that the type of titanyl phthalocyanine crystal is different. Therefore, when these titanyl phthalocyanine crystals are compared, the crystals 1 to 9 used in the examples and the crystal 10 used in the comparative examples are the same as the X-ray diffraction spectrum, but the precursor X The line diffraction spectrum is different.

  Therefore, even if it is the same titanyl phthalocyanine crystal as the X-ray diffraction spectrum, by using a titanyl phthalocyanine crystal obtained by crystallizing a precursor having a specific X-ray diffraction spectrum, the stability of chargeability during repeated use is improved. It has been found that an electrophotographic photosensitive member and an image forming apparatus excellent in stability against environmental fluctuations can be provided.

(Example 37)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the charge transport layer coating solution in Example 1 was changed to one having the following composition (referred to as an electrophotographic photosensitive member 13).
(Charge transport layer coating solution)
Tetrahydrofuran 100 parts by weight Polymer charge transport material (weight average molecular weight: 125000) 15 parts by weight of the following structural formula

下記構造式の可塑剤 ０．５重量部

0.5 parts by weight of a plasticizer having the following structural formula

（実施例３８〜４１、比較例１３〜１５）
［電子写真感光体の静電特性の評価３］
表７に記載の電子写真感光体を、図５に示すようなプロセスカートリッジに装着し、図４に示すような画像形成装置に搭載し、転写紙に転写される画像（ＩＳＯ／ＪＩＳ−ＳＣＩＤ画像Ｎ１（ポートレート））のカラー色の再現性を初期、及び２万枚印刷後に評価することで、電子写真感光体１、８、９〜１３の静電特性を評価した。また、表７に記載の電子写真感光体の長手方向１０点の膜厚を算術平均して平均膜厚を求め、初期と２万枚印刷後との平均膜厚の差から、電子写真感光体１、８、９〜１３の摩耗量を求めた。結果を表７に示す。

(Examples 38 to 41, Comparative Examples 13 to 15)
[Evaluation of electrostatic characteristics of electrophotographic photosensitive member 3]
An electrophotographic photosensitive member described in Table 7 is mounted on a process cartridge as shown in FIG. 5 and mounted on an image forming apparatus as shown in FIG. 4 to be transferred to a transfer sheet (ISO / JIS-SCID image). The electrostatic properties of the electrophotographic photoreceptors 1, 8, and 9 to 13 were evaluated by evaluating the reproducibility of the color of N1 (portrait) at the initial stage and after printing 20,000 sheets. Further, the average film thickness is obtained by arithmetically averaging the film thicknesses at 10 points in the longitudinal direction of the electrophotographic photosensitive member shown in Table 7, and the electrophotographic photosensitive member is determined from the difference in average film thickness between the initial and 20,000 printed sheets. The amount of wear of 1, 8, 9-13 was determined. The results are shown in Table 7.

  The charging means (3) is a contact roller charger, the exposure means (5) is a light source of 780 nm semiconductor laser (image writing by a polygon mirror), and the exposure means (5) is a 6% chart (A4 overall surface). On the other hand, characters equivalent to 6% are written on the average as the image area), a transfer belt is used as the transfer means (10), and a 660 nm LED is used as the light source of the charge removal means (2). The test environment is 23 ° C. and 55% RH. The charging conditions and exposure conditions (exposure amounts) were set so as to satisfy the following process conditions in the initial state.

Surface potential of unexposed area: −900V
Development bias: -650V (negative / positive development)
Surface potential of exposed area: -60V

表７から明らかなように、本実施例の電子写真感光体１、８、９、１３では、疲労後のカラーの再現性が良好であることが確認できた。これに対し、比較例の電子写真感光体１０〜１２では、疲労後のカラーの再現性が良くなかった。また、本実施例の電子写真感光体１３は、その他の電子写真感光体１、８、９、１０〜１２と比較して、摩耗量が小さかった。

As is clear from Table 7, it was confirmed that the electrophotographic photoreceptors 1, 8, 9, and 13 of this example had good color reproducibility after fatigue. On the other hand, in the electrophotographic photoreceptors 10 to 12 of the comparative examples, the color reproducibility after fatigue was not good. Further, the electrophotographic photosensitive member 13 of this example had a smaller amount of wear than the other electrophotographic photosensitive members 1, 8, 9, and 10-12.

  When the electrophotographic photoreceptors 1, 8, 9, and 13 of this example are compared with the electrophotographic photoreceptor 10 of the comparative example, they are manufactured in the same manner except that the type of titanyl phthalocyanine crystal is different. Therefore, when these titanyl phthalocyanine crystals are compared, the crystals 1, 8, 9 used in the examples and the crystal 10 used in the comparative examples are identical in X-ray diffraction spectrum, but the precursor Have different X-ray diffraction spectra.

  Therefore, even if it is the same titanyl phthalocyanine crystal as an X-ray diffraction spectrum, it is excellent in stability during repeated use by using a titanyl phthalocyanine crystal obtained by crystallizing a precursor having a specific X-ray diffraction spectrum. It has been found that an electrophotographic photosensitive member and a process cartridge for an image forming apparatus can be provided.

  As described above in detail, the electrophotographic photosensitive member of this example has at least 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. It has a maximum diffraction peak, and further has main diffraction peaks at 9.4 °, 9.6 °, and 24.0 °, and has a diffraction peak at 7.3 ° as the lowest-angled diffraction peak. A characteristic X-ray of CuKα obtained by crystal-transforming a titanyl phthalocyanine crystal having no peak between the peak at 7.3 ° and the peak at 9.4 ° and further having no diffraction peak at 26.3 ° As a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to (wavelength 1.542 mm), it has a maximum diffraction peak at least 26.2 °, and further 9.3 °, 10.5 °, 13.2 ° 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 7.1 °, comprising a photosensitive layer containing a titanyl phthalocyanine crystal having a diffraction peak at 28.3 °. As a result, according to the present embodiment, an electrophotographic photoreceptor excellent in the stability of chargeability during repeated use can be provided. Further, by using this electrophotographic photosensitive member, it is possible to provide an image forming apparatus and a process cartridge for the image forming apparatus that are excellent in the stability of chargeability during repeated use.

It is sectional drawing which showed an example of the structure of the electrophotographic photosensitive member of a present Example. It is sectional drawing which showed another example of the structure of the electrophotographic photoreceptor of a present Example. 1 is a schematic diagram illustrating an example of a structure of an image forming apparatus according to an embodiment. 1 is a schematic diagram illustrating an example of the structure of a tandem type full-color image forming apparatus according to an embodiment. It is the schematic which showed an example of the structure of the process cartridge of a present Example. 4 is a diagram showing an example of an X-ray diffraction spectrum of amorphous titanyl phthalocyanine obtained in Synthesis Example 1. FIG. 3 is a diagram showing an example of an X-ray diffraction spectrum of a precursor obtained in Synthesis Example 1. FIG. It is the figure which showed an example of the X-ray-diffraction spectrum of the titanyl phthalocyanine crystal | crystallization which crystallized the precursor of the synthesis example 1. 5 is a diagram showing an example of an X-ray diffraction spectrum of a precursor obtained in Comparative Synthesis Example 1. FIG. It is the figure which showed an example of the X-ray-diffraction spectrum of the mixed powder (mass ratio 97: 3) of the precursor of the synthesis example 1 and the pigment crystal described in Unexamined-Japanese-Patent No. Sho 61-239248. It is the figure which showed an example of the X-ray-diffraction spectrum of the mixed powder (mass ratio 97: 3) of the precursor of the comparative synthesis example 1 and the pigment crystal described in Unexamined-Japanese-Patent No. 61-239248. 6 is a diagram showing an example of an X-ray diffraction spectrum of a titanyl phthalocyanine crystal finally obtained in Comparative Synthesis Example 1. FIG.

Claims (12)

In an electrophotographic photosensitive member provided with a photosensitive layer containing at least a titanyl phthalocyanine crystal on a conductive support,
The titanyl phthalocyanine crystal has an irregular shape 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 1.542１．５) of CuKα. An organic solvent containing titanyl phthalocyanine in the presence of water and containing at least one organic solvent selected from tetrahydrofuran, cyclohexane, toluene, methylene chloride, carbon disulfide, orthodichlorobenzene, and 1,1,2-trichloroethane Obtained by crystal conversion by
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 at least 27.2 °, and further 9.4 ° and 9.6 °. , Having a main diffraction peak at 24.0 ° and a diffraction peak at 7.3 ° as the lowest angled diffraction peak, between the 7.3 ° peak and the 9.4 ° peak Using a titanyl phthalocyanine crystal that does not have a peak and does not have a diffraction peak at 26.3 °, a second crystal conversion was performed.
As a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray of CuKα (wavelength 1.542 mm), it has a maximum diffraction peak at least 26.2 °, and further 9.3 °, 10.5 ° , 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1 °, 28.3 °, titanyl phthalocyanine crystals having diffraction peaks. An electrophotographic photosensitive member characterized by the above. The photosensitive layer is formed by laminating a charge generation layer and a charge transport layer,
The charge generation layer has an indefinite shape 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 CuKα characteristic X-ray (wavelength 1.542Å). An organic solvent containing titanyl phthalocyanine in the presence of water and containing at least one organic solvent selected from tetrahydrofuran, cyclohexane, toluene, methylene chloride, carbon disulfide, orthodichlorobenzene, and 1,1,2-trichloroethane Obtained by crystal conversion by
As a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542Å) of the CuKα, it has a maximum diffraction peak at least 27.2 °, and further 9.4 °, 9.6 It has a major diffraction peak at 24.0 ° and a diffraction peak at 7.3 ° as the lowest angled diffraction peak, between the 7.3 ° peak and the 9.4 ° peak In addition, a titanyl phthalocyanine crystal having no diffraction peak at 26.3 ° was used for a second crystal conversion.
As a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542Å) of the CuKα, it has a maximum diffraction peak at least 26.2 °, and further 9.3 °, 10.5 Titanyl phthalocyanine crystals having diffraction peaks at °, 13.2 °, 15.1 °, 15.6 °, 16.1 °, 20.7 °, 23.2 °, 27.1 ° and 28.3 ° The electrophotographic photosensitive member according to claim 1, comprising: The electrophotographic photosensitive member according to claim 1, wherein the second crystal conversion is performed by treatment with a first organic solvent.   The electrophotographic photosensitive member according to claim 3, wherein the first organic solvent includes at least one organic solvent selected from a ketone solvent and an ether solvent. The electrophotographic photosensitive member according to any one of claims 1 to 4 , wherein the half width of the maximum diffraction peak of 7.0 to 7.5 ° of the amorphous titanyl phthalocyanine is 1 ° or more. . 6. The electrophotographic photosensitive member according to claim 1, wherein the amorphous titanyl phthalocyanine is synthesized without using a titanium halide. The electrophotographic photosensitive member according to claim 2 , wherein the charge transport layer contains a polymer charge transport material. 8. The electrophotographic photoreceptor according to claim 7 , wherein the polymer charge transport material is a polycarbonate having a triarylamine structure in the main chain or side chain. The image forming apparatus having at least a charging unit, an exposing unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of claims 1 to 8. An image forming apparatus. A plurality of image forming elements having at least charging means, exposure means, developing means, and electrophotographic photosensitive member are arranged, and the electrophotographic photosensitive member is the electrophotographic photosensitive member according to any one of claims 1 to 8. An image forming apparatus. An image forming apparatus in which an image forming apparatus process cartridge including at least one of charging means, exposure means, developing means, and cleaning means and an electrophotographic photosensitive member is detachably accommodated. An image forming apparatus, wherein the photoconductor is the electrophotographic photoconductor according to claim 1 . In a process cartridge for an image forming apparatus comprising at least one of a charging unit, an exposure unit, a developing unit, and a cleaning unit, and an electrophotographic photosensitive member, the electrophotographic photosensitive member is defined in claims 1 to 8. A process cartridge for an image forming apparatus, which is the electrophotographic photosensitive member according to any one of the above.

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