JP2005084350A - Electrophotographic photoreceptor, method for manufacturing the same and electrophotographic apparatus using the photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent occurrence of blue spots in a photoreceptor using hydroxy-gallium phthalocyanine, to thereby diminish black spots and fog on an image, and to also improve the stability of a CG liquid. <P>SOLUTION: An electrophotographic photoreceptor is made by applying a dispersion liquid obtained by dispersing hydroxy-gallium phthalocyanine in PVB having a viscosity of ≥90 mPa s when prepared as a 5 wt.% solution in THF. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrophotographic photoreceptor and an electrophotographic apparatus, and more specifically, an electrophotographic photoreceptor using hydroxygallium phthalocyanine and a polyvinyl butyral resin compound, a method for producing the same, and an electrophotography using the electrophotographic photoreceptor. The present invention relates to an apparatus and a process cartridge.

  Conventionally, many function-separated organic electrophotographic photoreceptors having a charge generation layer and a charge transport layer have been proposed and put into practical use. The charge generation layer in the photoreceptor is generally provided by applying and drying a charge generation layer coating obtained by dispersing organic pigment particles as a charge generation material in a solution in which a binder resin is dissolved in an organic solvent. .

  Since the charge generation material absorbs light in a wavelength region corresponding to the material and generates charge carriers, it is necessary to select a charge generation material suitable for the image exposure wavelength of the electrophotographic apparatus. In recent years, printers that apply electrophotographic technology have become widespread as printers for terminals, but these are laser beam printers that mainly use laser light as the light source, from the viewpoint of cost, size of the device, etc. Semiconductor lasers are often used. Since semiconductor lasers currently used mainly have a long oscillation wavelength of 650 to 820 nm, development of electrophotographic photosensitive members and charge generation materials having sufficient sensitivity to light in these wavelength regions has been promoted. .

  There are various phthalocyanine pigments as charge generation materials having high sensitivity to light having a wavelength of 650 to 820 nm, and one of them is hydroxygallium phthalocyanine.

  However, hydroxygallium phthalocyanine has the disadvantage that the dispersibility of pigment particles is poor compared with, for example, titanyl phthalocyanine, and it is difficult to obtain a coating for a charge generation layer with excellent coating properties. It was.

  In addition to the properties of the pigment particles themselves, the properties of the binder resin that disperses the pigment have a great influence on the coatability of the charge generation layer coating material. Many resins have been proposed as binder resins for use in the charge generation layer. Polyvinyl butyral resin is a resin that exhibits good dispersibility and adhesion to many types of pigments, as well as electrophotographic characteristics. Compounds are known. However, even when hydroxygallium phthalocyanine is dispersed in a polyvinyl butyral resin compound, depending on the conditions such as the composition and molecular weight of the polyvinyl butyral resin compound and the mixing ratio of the pigment to the binder resin, charge generation is not necessarily good. The layer coating could not be obtained.

  Specific problems that occur when the coating properties of the charge generation layer coating are poor include, specifically, pigment agglomeration during coating, causing spots (blue spots) in the charge generation layer and uneven coating. The phenomenon that it is easy can be mentioned. In particular, when the ratio of the charge generation material contained in the charge generation layer is high, the absolute amount of the resin contained in the charge generation layer is reduced, so that these problems appear more remarkably. Blue spots in the charge generation layer sometimes cause black spots, white spots and fog in the output image, while uneven coating of the charge generation layer causes uneven image density, particularly in the halftone area. Therefore, improvement of these problems has been strongly desired from the viewpoint of high image quality.

On the other hand, when storing finished paints, paints with poor coatability often lack the stability as paints, and re-aggregation or sedimentation of pigment particles may occur during storage, making the paint unusable. Therefore, the improvement of the stability of the paint has been strongly desired.
JP 2002-107972 A

  The object of the present invention is high sensitivity, low residual potential, no blue spots in the charge generation layer, so there are no black spots, white spots or fog in the output image, and there is no coating unevenness of the charge generation layer. Another object of the present invention is to provide an electrophotographic photosensitive member capable of obtaining a high-quality image without density unevenness.

  Another object of the present invention is to provide a method for producing an electrophotographic photosensitive member using a charge generation layer coating material excellent in coating property and stability as a coating material.

  Another object of the present invention is to provide an electrophotographic apparatus and a process cartridge having the electrophotographic photosensitive member.

  As a result of studying the coatability improvement of the coating for a charge generation layer using hydroxygallium phthalocyanine by the present inventors, when a polyvinyl butyral resin compound having a certain viscosity or more is used as a resin for dispersing hydroxygallium phthalocyanine, Even if the proportion of the charge generation material in the total solid component of the charge generation layer is 50% by mass or more and 85% by mass or less, the coating property as a paint is kept good, and black spots, white spots and fog, or charge generation It has been found that there is an effect in preventing image defects such as image density unevenness caused by uneven coating of the layer.

  That is, the electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member in which a charge generation layer and a charge transport layer are laminated on a conductive support, and the charge generation layer contains at least hydroxygallium phthalocyanine as a charge generation material. And a polyvinyl butyral resin compound characterized in that the viscosity measured with a 5% by mass THF solution as a binder resin is 90 mPa · s or more, and total charge generation in all solid components of the charge generation layer The electrophotographic photosensitive member is characterized in that the proportion of the material is 50% by mass or more and 85% by mass or less.

  In the method for producing an electrophotographic photoreceptor of the present invention, a charge generation layer is formed by applying a dispersion in which at least the hydroxygallium phthalocyanine is dispersed as a charge generation material in an organic solvent solution containing the polyvinyl butyral resin compound. It is a method for producing an electrophotographic photosensitive member characterized by forming.

  In addition, an electrophotographic apparatus of the present invention includes the above-described electrophotographic photosensitive member.

  Further, the process cartridge of the present invention integrally supports at least one means selected from the group consisting of the above-described electrophotographic photosensitive member and charging means, developing means and cleaning means, and is detachable from the main body of the electrophotographic apparatus. It is characterized by being.

  In the polyvinyl butyral resin compound used in the present invention, the reason why the viscosity measured by the 5% by mass THF solution is 90 mPa · s or more is necessary because if the viscosity is lower than this, the fluidity of the coating becomes too high. This is because the aggregation of the pigment, which is the cause of the spots, is likely to occur, and the coating unevenness due to the influence of the fine unevenness of the underlying layer and the flow of the paint during coating is likely to occur. In addition, as described above, a paint that easily causes aggregation of the pigment has a problem that the precipitation of the pigment easily occurs in terms of storage stability.

  As described above, according to the present invention, in an electrophotographic photosensitive member in which a charge generation layer and a charge transport layer are laminated on a conductive support, the charge generation layer contains at least hydroxygallium phthalocyanine as a charge generation material. And a polyvinyl butyral resin compound characterized by having a viscosity in a 5% by mass THF solution of 90 mPa · s or more as a binder resin, and the total charge generation material occupies in the total solid component of the charge generation layer By adjusting the ratio to 50% by mass or more and 85% by mass or less, the electrophotographic photosensitive member has high sensitivity, no blue spots in the charge generation layer, and a satisfactory level of image defects due to black spots and fog in the output image. And a method for producing the electrophotographic photosensitive member using the charge generating layer coating material having excellent dispersibility and storage stability of the charge generating material, and a process cartridge using the electrophotographic photosensitive member. It is possible to provide a cartridge and an electrophotographic apparatus.

  The present invention is described in detail below.

  The electrophotographic photoreceptor according to the present invention is a functionally separated organic electron in which a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material are laminated on a conductive support to form a photosensitive layer. It is a photographic photoreceptor. The stacking relationship between the charge generation layer and the charge transport layer may be reversed.

  The support used in the present invention may be any support as long as it has conductivity, such as aluminum, aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold, and the like. Platinum can be used. In addition, plastics (eg, polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, and polyethylene fluoride) that have a layer formed by vacuum deposition of aluminum, aluminum alloy, indium oxide, tin oxide, and indium oxide-tin oxide alloy are used. Ethylene), conductive particles (for example, aluminum powder, titanium oxide, tin oxide, zinc oxide, carbon black and silver particles) coated with a suitable binder resin on a plastic or the above support, conductive particles It is possible to use a support obtained by impregnating plastic with paper or a plastic having a conductive polymer.

  In the present invention, an undercoat layer having a barrier function and an adhesive function can be provided between the support and the photosensitive layer. Materials for the undercoat layer include polyvinyl alcohol, polyethylene oxide, ethyl cellulose, methyl cellulose, casein, polyamide (nylon 6, nylon 66, nylon 610, copolymer nylon, N-alkoxymethylated nylon, etc.), polyurethane, glue, aluminum oxide and Gelatin or the like is used. The film thickness is 0.1 to 10 μm, preferably 0.5 to 5 μm.

  The present invention is characterized in that at least hydroxygallium phthalocyanine is selected as the charge generation material, and at least a polyvinyl butyral resin described later is used as the binder resin.

  If necessary, a phthalocyanine pigment other than hydroxygallium phthalocyanine, various perylene pigments, or an azo pigment may be mixed and used as a charge generation material. On the other hand, examples of the binder resin include polyester, acrylic resin, polyvinylcarbazole, A resin such as phenoxy resin, polycarbonate, polystyrene, polyvinyl acetate, polysulfone, polyarylate, vinylidene chloride, acrylonitrile copolymer, and polyvinyl benzal may be mixed with the polyvinyl butyral resin used in the present invention.

  With respect to the method for producing hydroxygallium phthalocyanine used in the present invention, for example, JP-A-5-263007, JP-A-6-93203, JP-A-8-100134, JP-A-10-67946, etc. Discloses a method for producing several kinds of hydroxygallium phthalocyanine crystals. Among the hydroxygallium phthalocyanine crystals, Bragg angle 2θ ± 0.2 ° in X-ray diffraction of CuKα disclosed in JP-A-5-263007 is 7.5 °, 9.9 °, 12.5 °, A hydroxygallium phthalocyanine crystal having strong peaks at 16.3 °, 18.6 °, 25.1 °, and 28.3 °, and Bragg in X-ray diffraction of CuKα disclosed in JP-A-10-67946 It is known that a hydroxygallium phthalocyanine crystal having an angle 2θ ± 0.2 ° having the strongest peak at 28.1 ° has particularly high sensitivity and is excellent in chargeability and stability as a crystal.

  The polyvinyl butyral resin compound used in the present invention is generally produced through an acetalization step in which butyraldehyde is reacted with polyvinyl alcohol (PVA). In this step, butylformaldehyde, acetaldehyde or the like is used if necessary. Aldehydes other than aldehydes may be mixed with butyraldehyde. It is known that in the acetalization step, PVA is not completely acetalized and an unreacted hydroxyl group always remains. Further, a small amount of acetyl group remains during saponification in the production process of PVA as a material.

  When only butyraldehyde is used in the acetalization, the structure of the polyvinyl butyral resin is represented by the following formula (1).

（式中ｌ、ｍ、ｎは１以上の整数を表す。）
また、例えばアセタール化の際にブチルアルデヒド以外のアルデヒドも混合して用いた場合には部分アセタール化ポリビニルブチラール樹脂ができるが、これは下記式（２）で表される。

(In the formula, l, m and n represent an integer of 1 or more.)
Further, for example, when an aldehyde other than butyraldehyde is mixed and used in the acetalization, a partially acetalized polyvinyl butyral resin can be produced, which is represented by the following formula (2).

（式中Ｒは水素原子、ブチラール基を除くアルキル基等を表し、ｌ、ｍ、ｎ、ｐは１以上の整数を表す。）
また、ポリビニルブチラール樹脂化合物としては、各種の置換基を有するものなどが考えられる。

(In the formula, R represents a hydrogen atom, an alkyl group other than a butyral group, etc., and l, m, n, and p represent an integer of 1 or more.)
Moreover, what has various substituents etc. are considered as a polyvinyl butyral resin compound.

  The viscosity of the polyvinyl butyral resin compound was measured under the following conditions. The sample polyvinyl butyral resin compound was dissolved in THF to prepare a 5% by mass solution and used for the measurement.

Measuring device: Single cylinder type rotational viscometer bismetron type VS-A1 (manufactured by Shibaura System Co., Ltd.)
Measurement at room temperature 23 ° C. When the hydroxygallium phthalocyanine is dispersed in the polyvinyl butyral resin compound, a ball mill, a sand mill, a roll mill, an attritor, a liquid collision type disperser, or the like can be used.

  Examples of the solvent used for dispersion and dilution after dispersion include ketones such as acetone, methyl ethyl ketone, 4-methoxy-4-methyl-2-pentanone and cyclohexanone; ethers such as tetrahydrofuran, dioxane and ethylene glycol monomethyl ether; Esters such as methyl acetate and ethyl acetate; aliphatic halogen hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride and trichloroethylene; or aromatics such as benzene, toluene, xylene, ligroin, chlorobenzene and dichlorobenzene Compound etc. are mentioned. As the solvent used for dissolving the resin, it is necessary to select and use an appropriate solvent according to the polyvinyl butyral resin compound to be used. In addition, the solvent used for dispersion | distribution or dilution may use only 1 type, or may mix and use 2 or more types.

  In the present invention, the content of the charge generation material in the charge generation layer is 50 to 85% by mass with respect to the total solid components in the charge generation layer.

  The film thickness of the charge generation layer formed by applying and drying the charge generation layer coating material is 0.01 to 10 μm, preferably 0.1 to 3 μm.

  The charge transport layer is formed by applying and drying a paint in which a charge transport material and a binder resin are mainly dissolved in a solvent. Examples of the charge transport material include various triarylamine compounds, hydrazone compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, triallylmethane compounds, and the like. Examples of the binder resin used for the charge transport layer include polyester, acrylic resin, polyvinyl carbazole, phenoxy resin, polycarbonate, polyvinyl butyral, polystyrene, polyvinyl acetate, polysulfone, polyarylate, vinylidene chloride, acrylonitrile copolymer, polyvinyl benzal, and the like. These resins are used.

  The charge transport material and the charge transport layer binder resin may be used alone or in combination of two or more. The content of the charge transport material is preferably 30 to 70% by mass with respect to the charge transport layer. The thickness of the charge transport layer is in the range of 5 to 40 μm, preferably 10 to 30 μm.

  The electrophotographic photoreceptor of the present invention may be provided with a protective layer on the outermost surface as necessary. The protective layer is made by dissolving a resin such as polyester, polycarbonate (polycarbonate Z, modified polycarbonate, etc.), polyurethane, acrylic resin, epoxy resin, silicone resin, phenol resin and vinyl chloride-vinyl acetate copolymer with an appropriate organic solvent. It can be formed by applying and drying on the layer. The thickness of the protective layer is preferably 0.05 to 20 μm. Moreover, you may include electroconductive particle etc. in a protective layer. As the conductive particles, metal oxides such as tin oxide particles are preferable.

  As a coating method for each layer mentioned above, a coating method such as a dipping method, a spray coating method, a spinner coating method, a bead coating method, a blade coating method, and a beam coating method can be used.

  Each layer may contain various additives such as a dispersant, an antioxidant, an ultraviolet ray inhibitor, and a lubricant as necessary.

  Next, an electrophotographic apparatus using the electrophotographic photosensitive member of the present invention will be described.

  FIG. 1 shows a schematic configuration of an electrophotographic apparatus having a process cartridge using the electrophotographic photosensitive member of the present invention. In the figure, reference numeral 1 denotes a drum type photoconductor of the present invention, which is driven to rotate around a shaft 2 in the direction of an arrow at a predetermined peripheral speed. In the rotation process, the photosensitive member 1 is uniformly charged with a predetermined positive or negative potential on its peripheral surface by the primary charging unit 3, and then image exposure light 4 from image exposure unit (not shown) such as slit exposure or laser beam scanning exposure. Receive. In this way, electrostatic latent images are sequentially formed on the circumferential surface of the photoreceptor.

  The formed electrostatic latent image is then developed with toner by the developing unit 5, and the developed toner image is rotated between the photosensitive member 1 and the transfer unit 6 from a paper feeding unit (not shown). The transfer means 6 sequentially transfers the images to the transfer material 7 that has been periodically sent and sent. The transfer material 7 that has received the image transfer is separated from the surface of the photosensitive member, introduced into the image fixing means 8, and subjected to image fixing, and printed out as a copy (copy). After the image transfer, the surface of the photoreceptor 1 is cleaned by removing the transfer residual toner by the cleaning unit 9 and further subjected to the charge removal process by the pre-exposure 10 from the pre-exposure (not shown), and then the image is repeatedly performed. Used for forming. When the primary charging means 3 is a contact charging method using a charging roller or the like, pre-exposure is not necessarily required.

  In the present invention, among the above-described photosensitive member 1, primary charging unit 3, developing unit 5, and cleaning unit 9, a plurality of components are integrally combined as a process cartridge, and this process cartridge is a copying machine. Or an electrophotographic apparatus main body such as a laser beam printer. For example, at least one of the primary charging unit 3, the developing unit 5 and the cleaning unit 9 is integrally supported with the photosensitive member 1 to form a cartridge, and the process cartridge can be attached to and detached from the apparatus main body using guide means such as the rail 12 of the apparatus main body. 11 can be set. In addition, when the electrophotographic apparatus is a copying machine or a printer, the image exposure light 4 uses reflected light or transmitted light from the original, or reads the original with a sensor, converts it into a signal, and performs laser according to this signal. Light emitted by scanning a beam, driving a light emitting diode array, driving a liquid crystal shutter array, or the like.

  Hereinafter, the present invention will be described with reference to examples.

  “%” And “part” shown below mean “% by mass” and “part by mass”, respectively.

  50 parts of titanium oxide powder coated with tin oxide containing 10% antimony oxide, 25 parts of resol type phenol resin, 20 parts of methyl cellosolve, 5 parts of methanol and silicone oil (polydimethylsiloxane / polyoxyalkylene copolymer, A conductive layer coating material was prepared by dispersing 0.002 part of (average molecular weight 3,000) in a sand mill using 1 mmφ glass beads for 2 hours. A conductive layer coating was dip-coated on an aluminum cylinder (φ30 mm) and dried at 140 ° C. for 30 minutes to form a conductive layer having a thickness of 20 μm.

  On the conductive layer, 5 parts of 6-66-610-12 quaternary polyamide copolymer is dip-coated with a solution prepared by dissolving 70 parts of methanol and 25 parts of butanol in a mixed solvent, dried, and an undercoat layer having a thickness of 1 μm. Formed.

  Next, in a resin solution obtained by dissolving 1 part of polyvinyl butyral resin compound A (manufactured by Sekisui Chemical Co., Ltd.) having a viscosity shown in Table 1 in 39 parts of cyclohexanone, the Bragg angle 2θ ± 0.2 ° in X-ray diffraction of CuKα is Add 3.5 parts of hydroxygallium phthalocyanine crystals having strong peaks at 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 °, 28.3 °, This was dispersed in a sand mill using 1 mmφ glass beads for 3 hours to prepare a dispersion. Further, 50 parts of cyclohexanone and 130 parts of ethyl acetate were added to the dispersion and diluted to prepare a coating material for a charge generation layer. The charge generation layer coating material was dip-coated on the undercoat layer and dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.15 μm.

  FIG. 2 shows a powder X-ray diffraction pattern of the hydroxygallium phthalocyanine crystal. The powder X-ray diffraction was measured using CuKα rays under the following conditions.

Measuring instrument used: Fully automated X-ray diffractometer MXP18, manufactured by Mac Science
X-ray tube: Cu
Tube voltage: 50KV
Tube current: 300mA
Scan method: 2θ / θ scan Scan speed: 2 deg. / Min
Sampling interval: 0.020 deg.
Start angle (2θ): 5 deg.
Stop angle (2θ): 40 deg.
Divergence slit: 0.5 deg.
Scattering slit: 0.5 deg.
Receiving slit: 0.3 deg.
Next, 10 parts of charge transport material having the following structural formula is used.

とポリカーボネート樹脂（商品名：ユーピロンＺ−２００、三菱ガス化学）１０部をクロロベンゼン６０部に溶解し、電荷輸送層用塗料を調製した。電荷発生層上に電荷輸送層用塗料を浸漬塗布し、１２０℃で６０分間乾燥して、膜厚２５μｍの電荷輸送層を形成した。こうして電子写真感光体を作成した。

10 parts of polycarbonate resin (trade name: Iupilon Z-200, Mitsubishi Gas Chemical) was dissolved in 60 parts of chlorobenzene to prepare a coating for a charge transport layer. A charge transport layer coating material was dip coated on the charge generation layer and dried at 120 ° C. for 60 minutes to form a charge transport layer having a thickness of 25 μm. Thus, an electrophotographic photosensitive member was prepared.

An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the charge generation layer resin in Example 1 was changed to polyvinyl butyral resin compound B (manufactured by Sekisui Chemical Co., Ltd.) having a different viscosity.
(Comparative Example 1)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge generation layer resin in Example 1 was changed to a polyvinyl butyral resin compound C (manufactured by Sekisui Chemical Co., Ltd.) having a different viscosity.
(Comparative Example 2)
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the charge generation layer resin in Example 1 was changed to polyvinyl butyral resin compound D (manufactured by Sekisui Chemical Co., Ltd.) having a different viscosity.

  The electrophotographic photoreceptors prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were visually observed, and the presence or absence of blue spots in the charge generation layer was observed. Subsequently, each electrophotographic photosensitive member was installed in a laser beam printer (trade name LBP-1760, manufactured by Canon Inc.), and the initial white and white at a temperature of 32.5 ° C., a high temperature of 80% and high humidity were obtained. A halftone image set to a dot density of one dot and one space was output, and black spots and fog appearing in the solid white image and density unevenness of the halftone image were visually evaluated. The results are shown in Table 1.

一方、実施例１、２および比較例１、２で作成した電荷発生層用塗料の液の状態を、分散液作成直後および１ヶ月間静置保存後に目視にて評価した。結果を表２に示す。

On the other hand, the state of the liquid of the charge generation layer coating material prepared in Examples 1 and 2 and Comparative Examples 1 and 2 was visually evaluated immediately after the dispersion was prepared and after storage for 1 month. The results are shown in Table 2.

  An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport material in Example 1 was replaced with a charge transport material having the following structural formula.

  An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport material in Example 1 was replaced with a charge transport material having the following structural formula.

  An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport material in Example 1 was replaced with a charge transport material having the following structural formula.

  An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the charge transport material in Example 1 was replaced with a charge transport material having the following structural formula.

（比較例３〜６）
比較例３〜５における電荷発生層用樹脂を前記ポリビニルブチラール樹脂化合物Ｄ（積水化学工業社製）に変えた他は、比較例３〜５と同様にして電子写真感光体を作成した。

(Comparative Examples 3-6)
An electrophotographic photosensitive member was prepared in the same manner as in Comparative Examples 3 to 5 except that the charge generation layer resin in Comparative Examples 3 to 5 was changed to the polyvinyl butyral resin compound D (manufactured by Sekisui Chemical Co., Ltd.).

  The electrophotographic photoreceptors prepared in Examples 3 to 6 and Comparative Examples 3 to 6 were evaluated in the same manner as in Example 2 with respect to blue spots in the charge transport layer and initial black spots and fog at high temperature and high humidity. . The results are shown in Table 3.

（比較例７）
比較例２において、ヒドロキシガリウムフタロシアニン結晶の使用量を２部とし、前記ポリビニルブチラール樹脂化合物をＤ（積水化学工業社製）とし、かつ該樹脂の使用量を２．５部とした他は比較例２と同様にして電子写真感光体を作成した。
（比較例８）
比較例７において、電荷発生層の膜厚を０．２７μｍとした他は比較例７と同様にして電子写真感光体を作成した。

(Comparative Example 7)
Comparative Example 2 except that the amount of hydroxygallium phthalocyanine crystal used was 2 parts, the polyvinyl butyral resin compound was D (manufactured by Sekisui Chemical Co., Ltd.), and the amount of resin used was 2.5 parts. In the same manner as in Example 2, an electrophotographic photoreceptor was prepared.
(Comparative Example 8)
An electrophotographic photosensitive member was prepared in the same manner as in Comparative Example 7 except that the thickness of the charge generation layer was changed to 0.27 μm in Comparative Example 7.

  The particle diameter of the hydroxygallium phthalocyanine crystal in the charge generation layer coating material prepared in Comparative Example 7 was 0.18 μm, and the dispersion state of the pigment was improved as compared with Comparative Example 2. In addition, no blue spots were observed in the charge generation layer of the electrophotographic photosensitive member produced in Comparative Examples 7 and 8. However, when the same image evaluation as that performed on the electrophotographic photosensitive member produced in Example 1 was performed, the sensitivity of the electrophotographic photosensitive member of Comparative Example 7 was insufficient, resulting in a thin halftone image. Further, the same image evaluation was performed on the electrophotographic photosensitive member of Comparative Example 8. As a result, although the sensitivity of the photosensitive member was appropriate, the entire white image was fogged.

1 shows a schematic configuration of an electrophotographic apparatus having a process cartridge using the electrophotographic photosensitive member of the present invention. 2 shows a powder X-ray diffraction pattern of hydroxygallium phthalocyanine crystal.

Claims (5)

  In an electrophotographic photosensitive member in which a charge generation layer and a charge transport layer are laminated on a conductive support, the charge generation layer contains at least hydroxygallium phthalocyanine as a charge generation material, and 5% by mass THF as a binder resin A polyvinyl butyral resin compound having a viscosity measured by a solution of 90 mPa · s or more is contained, and the ratio of the total charge generation material in the total solid component of the charge generation layer is 50% by mass or more and 85% by mass or less. An electrophotographic photoreceptor characterized by the above.   The electrophotographic photoreceptor, wherein the hydroxygallium phthalocyanine according to claim 1 is a hydroxygallium phthalocyanine crystal having a Bragg angle 2θ ± 0.2 ° in the X-ray diffraction of CuKα of 7.4 ° and a strong peak at 28.2 °. .   2. The method for producing an electrophotographic photoreceptor according to claim 1, wherein a dispersion in which at least hydroxygallium phthalocyanine is dispersed as a charge generation material is applied to an organic solvent solution containing the polyvinyl butyral resin compound to form a charge generation layer. A method for producing an electrophotographic photosensitive member, comprising forming the electrophotographic photosensitive member.   An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1. The electrophotographic photosensitive member according to claim 1 and at least one means selected from the group consisting of a charging means, a developing means and a cleaning means are integrally supported and detachable from the main body of the electrophotographic apparatus. Process cartridge.

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