JP2007108650A - Image forming apparatus, image forming method and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus containing an electrophotographic photoreceptor which can be injection-charged even in positive charging and has high sensitivity and low residual potential. <P>SOLUTION: The image forming apparatus contains the electrophotographic photoreceptor 11 having a configuration in which at least a photosensitive layer and a surface protective layer are sequentially stacked on a conductive support and a charging member disposed in contact with the electrophotographic photoreceptor, wherein the electrophotographic photoreceptor is injection-charged by applying a voltage to the charging member. The surface protective layer of the electrophotographic photoreceptor contains a conductive metal oxide, and the photosensitive layer or the surface protective layer contains a naphthalenecarboxylic acid derivative of formula (1) or a naphthalenecarboxylic acid derivative of formula (1-2), wherein R1 and R2 each independently represent hydrogen atom or a substituted or unsubstituted alkyl, cycloalkyl or aralkyl; R3-R14 each independently represent hydrogen atom, halogen, cyano, nitro, amino, hydroxyl or a substituted or unsubstituted alkyl, cycloalkyl or aralkyl; n is a repeating unit and represents an integer of 1-100. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus. More specifically, the present invention relates to an image forming apparatus for injecting and charging an electrophotographic photosensitive member by applying a voltage to a charging member disposed in contact with the electrophotographic photosensitive member having a structure in which a photosensitive layer and a surface protective layer are sequentially laminated.

  A novel naphthalenecarboxylic acid derivative of the formula (2) suitable as an electron transport material in an organic electrophotographic photoreceptor and a highly sensitive electrophotographic photoreceptor using the same are disclosed (for example, see Patent Document 1).

[式中、Ｘ、Ｚは、それぞれ独立に水素原子、置換または未置換のアルキル基、置換または未置換のシクロアルキル基、置換または未置換のアラルキル基、置換または未置換のアリール基からなる群より選ばれる基であって、Ｙは、置換または未置換のアルキレン基もしくは置換または未置換のシクロアルキレン基を表す。]
しかしながら、この電子写真感光体は、従来品よりも高感度としているが、感度に関する記載がなく、また５０００枚程度の耐久性を評価しているだけである。

Wherein X and Z are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group. Wherein Y represents a substituted or unsubstituted alkylene group or a substituted or unsubstituted cycloalkylene group. ]
However, although this electrophotographic photosensitive member has higher sensitivity than the conventional product, there is no description regarding sensitivity, and only durability of about 5000 sheets is evaluated.

  In addition, a magnetic brush roller is provided in which a photosensitive layer having a charge injection layer is provided on a conductive substrate through which light is transmitted, and a developing nip is formed between the photosensitive member and the photosensitive member, and charging and developing are performed in the developing nip. And an exposure unit that exposes the photosensitive layer from the back side, and develops toner in the non-image area on the photosensitive drum by applying a voltage in which a DC voltage and an AC voltage are superimposed on the magnetic brush roller. An image forming apparatus that is pulled back to a sleeve is disclosed (for example, see Patent Document 2).

  However, this image forming apparatus is an OPC photosensitive member negatively charged type, and it is necessary to superimpose a -200V DC voltage and a sinusoidal AC voltage with a frequency of 1800 Hz and a peak-to-peak voltage of 2 kV for injection charging. Can not do.

In addition, a magnetic brush of magnetic particles that contacts a member to be charged, having a charge injection layer of 10 ^{9 to} 10 ¹⁴ Ω · cm on the surface, a magnetic brush charger that charges the member to be charged, and a magnetic brush charger In a charging device having a voltage applying means for applying a voltage and a resistor connected in a charging circuit including an object to be charged, the resistance of the magnetic particles is 10 ^{6 to} 10 ⁹ Ωcm, and the resistor is a magnetic brush It has a resistance that is 0.5 times or more of the resistance of the charger itself and the resistance of the charging circuit is 10 ⁷ Ω or less, and a temperature and humidity environment of 15 ° C, 10% to 33 ° C, 90% The resistance fluctuation of the resistor is smaller than the resistance fluctuation of the magnetic brush charger alone, thereby providing good environmental stability, thereby preventing the detachment of the conductive magnetic particles from the magnetic brush portion or Reduced conductive magnetism A charging device that prevents deterioration of charging performance due to separation of particles is disclosed (for example, see Patent Document 3).

  However, this charging device has only an injection charging example at a DC voltage of −700 V for an OPC photoreceptor having a charge injection layer on the surface, and no positive charging example.

  Further, in the electrophotographic apparatus having the electrophotographic photosensitive member, the contact charging member, the exposing unit, the developing unit, and the transferring unit, the surface layer of the electrophotographic photosensitive member may be a curable acrylic monomer having a reactive acrylic group or a methacrylic group. Contains a resin and conductive powder formed by polymerization of the oligomer, and the conductive powder is surface-treated with a coupling agent having a reactive acrylic group or methacryl group, and the charge is injected There has been disclosed an electrophotographic apparatus that can perform good injection charging by being charged, can obtain an excellent image, and has a sufficiently long durable life of a photoreceptor (see, for example, Patent Document 4).

  However, in this electrophotographic apparatus, a DC voltage of −700 V is applied from the charging bias power source and only injection charging is performed at −680 V, and there is no positive charging example.

  In addition, the toner image on the photosensitive drum is transferred in a color image forming apparatus in which a low voltage is applied to the photosensitive drum having a charge injection layer outside the photosensitive layer through a magnetic brush and charged by injection. There has been disclosed a color image forming apparatus in which the remaining transfer toner remaining after is collected by a developing device corresponding to each color toner, and the toner is recycled (for example, see Patent Document 5).

  However, in this color image forming apparatus, the surface protective layer has a diamond carbon structure containing hydrogen or an amorphous carbon structure, so that image blurring is likely to occur during repeated use under high temperature and high humidity, and charge injection. Since it is charged to −500 V by charging, ozone is likely to be generated.

  Also disclosed is a charge transport agent for electrophotographic photoreceptors comprising a diphenoquinone compound represented by the following formula (3).

（式中、R1乃至R8は、水素原子，炭素数１乃至20のアルキル基，シクロアルキル基，アリール基，アミノ基及びアルコキシ基から選ばれる１種又は２種以上であり、ただしR1乃至R8の全てが水素原子である場合を除く。）
しかし、この電子写真感光体用電荷輸送剤は、積層型電子写真用感光体の感度を正帯電で測定しているが感度が遅いなどの問題がある。
特開２００５−１５４４０９号公報 特開平６−２０２４１２号公報 特許第３４９５８３９号 特開平１１−９５４７４号公報 特開２００１−１２５３７５号公報 特許第２７１８０４８号

(Wherein R1 to R8 are one or more selected from a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group, an aryl group, an amino group, and an alkoxy group, provided that R1 to R8 are (Except when all are hydrogen atoms)
However, this charge transfer agent for electrophotographic photoreceptors has a problem that the sensitivity of the laminated electrophotographic photoreceptor is measured by positive charging, but the sensitivity is slow.
JP 2005-154409 A Japanese Patent Application Laid-Open No. 6-20212 Japanese Patent No. 3,495,839 Japanese Patent Laid-Open No. 11-95474 JP 2001-125375 A Japanese Patent No. 2718048

  Therefore, an object of the present invention is to provide an image forming apparatus that solves the above-described problems. More specifically, in an image forming apparatus that injects and charges an electrophotographic photosensitive member by applying a voltage to a charging member disposed in contact with the electrophotographic photosensitive member having a structure in which a photosensitive layer and a surface protective layer are sequentially laminated, positive charging is performed. The present invention also aims to provide an image forming apparatus having an electrophotographic photosensitive member capable of injection charging, having high sensitivity and low residual potential.

  That is, according to the present invention, as described in claim 1, an electrophotographic photoreceptor having a configuration in which at least a photosensitive layer and a surface protective layer are sequentially laminated on a conductive support, and the electrophotographic photoreceptor are disposed in contact with each other. In an image forming apparatus having a charging member and injecting and charging the electrophotographic photosensitive member by applying a voltage to the charging member, the surface protective layer of the electrophotographic photosensitive member contains a conductive metal oxide, The photosensitive layer or the surface protective layer contains an naphthalenecarboxylic acid derivative represented by the formula (1).

「式中、Ｒ１、Ｒ２は、それぞれ独立に水素原子、置換又は無置換のアルキル基、置換又は無置換のシクロアルキル基、置換又は無置換のアラルキル基からなる群より選ばれる基を表し、Ｒ３、Ｒ４、Ｒ５、Ｒ６、Ｒ７、Ｒ８、Ｒ９、Ｒ１０はそれぞれ独立に水素原子、ハロゲン原子、シアノ基、ニトロ基、アミノ基、水酸基、置換又は無置換のアルキル基、置換又は無置換のシクロアルキル基、置換又は無置換のアラルキル基からなる群より選ばれる基を表す。」
請求項１に記載の発明によれば、感光層及び表面保護層を順次積層した構成の電子写真感光体に接触配置された帯電部材電圧を印加することにより電子写真感光体を注入帯電する画像形成装置において、電子写真感光体の表面保護層が、導電性金属酸化物を含有し、且つ感光層又は表面保護層が式（１）のナフタレンカルボン酸誘導体を含有することにより正帯電においても注入帯電可能で高感度、低残留電位の電子写真感光体を有する画像形成装置を提供することができる。

"Wherein R1 and R2 each independently represents a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aralkyl group, and R3 , R4, R5, R6, R7, R8, R9, R10 are each independently a hydrogen atom, a halogen atom, a cyano group, a nitro group, an amino group, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group. Represents a group selected from the group consisting of a group, a substituted or unsubstituted aralkyl group.
According to the first aspect of the present invention, image formation is performed by injecting and charging the electrophotographic photosensitive member by applying a charging member voltage disposed in contact with the electrophotographic photosensitive member having a structure in which a photosensitive layer and a surface protective layer are sequentially laminated. In the apparatus, the surface protective layer of the electrophotographic photosensitive member contains a conductive metal oxide, and the photosensitive layer or the surface protective layer contains a naphthalenecarboxylic acid derivative of the formula (1), so that injection charging is possible even in positive charging. An image forming apparatus having an electrophotographic photosensitive member capable of high sensitivity and low residual potential can be provided.

  The invention according to claim 2 includes an electrophotographic photoreceptor having a configuration in which at least a photosensitive layer and a surface protective layer are sequentially laminated on a conductive support, and a charging member disposed in contact with the electrophotographic photoreceptor. In the image forming apparatus for injecting and charging the electrophotographic photosensitive member by applying a voltage to the charging member, the surface protective layer of the electrophotographic photosensitive member contains a conductive metal oxide and the photosensitive layer or This is achieved by an image forming apparatus characterized in that the surface protective layer contains a naphthalenecarboxylic acid derivative of the formula (1-2).

（式中、Ｒ１、Ｒ２は、それぞれ独立に水素原子、置換又は無置換のアルキル基、置換又は無置換のシクロアルキル基、置換又は無置換のアラルキル基からなる群より選ばれる基を表し、Ｒ３、Ｒ４、Ｒ５、Ｒ６、Ｒ７、Ｒ８、Ｒ９、Ｒ１０、Ｒ１１、Ｒ１２、Ｒ１３、Ｒ１４はそれぞれ独立に水素原子、ハロゲン原子、シアノ基、ニトロ基、アミノ基、水酸基、置換又は無置換のアルキル基、置換又は無置換のシクロアルキル基、置換又は無置換のアラルキル基からなる群より選ばれる基を表し、ｎは繰り返し単位であり、１から１００までの整数を表す。）
請求項２に記載の発明によれば、感光層及び表面保護層を順次積層した構成の電子写真感光体に接触配置された帯電部材電圧を印加することにより電子写真感光体を注入帯電する画像形成装置において、電子写真感光体の表面保護層が、導電性金属酸化物を含有し、且つ感光層又は表面保護層が式（１−２）のナフタレンカルボン酸誘導体を含有することにより正帯電においても注入帯電可能で高感度、低残留電位の電子写真感光体を有する画像形成装置を提供することができる。

Wherein R 1 and R 2 each independently represent a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aralkyl group, and R 3 , R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14 are each independently a hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, substituted or unsubstituted alkyl group Represents a group selected from the group consisting of a substituted or unsubstituted cycloalkyl group and a substituted or unsubstituted aralkyl group, and n is a repeating unit and represents an integer of 1 to 100.)
According to the second aspect of the present invention, image formation is performed by injecting and charging the electrophotographic photosensitive member by applying a charging member voltage disposed in contact with the electrophotographic photosensitive member having a structure in which a photosensitive layer and a surface protective layer are sequentially laminated. In the apparatus, the surface protective layer of the electrophotographic photosensitive member contains a conductive metal oxide, and the photosensitive layer or the surface protective layer contains a naphthalenecarboxylic acid derivative of the formula (1-2). It is possible to provide an image forming apparatus having an electrophotographic photosensitive member capable of injection charging, high sensitivity, and low residual potential.

  The invention according to claim 3 is the invention according to claim 1 or 2, further comprising a naphthalenecarboxylic acid derivative represented by the following formula (1-3) in addition to the naphthalenecarboxylic acid derivative. And

（式中、Ｒ１5、Ｒ16は、それぞれ独立に水素原子、置換又は無置換のアルキル基、置換又は無置換のシクロアルキル基、置換又は無置換のアラルキル基からなる群より選ばれる基を表し、Ｒ17、Ｒ18、Ｒ19、Ｒ20はそれぞれ独立に水素原子、ハロゲン原子、シアノ基、ニトロ基、アミノ基、水酸基、置換又は無置換のアルキル基、置換又は無置換のシクロアルキル基、置換又は無置換のアラルキル基からなる群より選ばれる基を表す。）
請求項３に記載の発明によれば、感光層及び表面保護層を順次積層した構成の電子写真感光体に接触配置された帯電部材電圧を印加することにより電子写真感光体を注入帯電する画像形成装置において、電子写真感光体の表面保護層が、導電性金属酸化物を含有し、且つ感光層又は表面保護層が式（１）、もしくは式（１−２）のナフタレンカルボン酸誘導体に加えて、さらに式（１−３）で表されるナフタレンカルボン酸誘導体を含有することにより、さらに耐ガス性、耐摩耗性を有する画像形成装置を提供することができる。

Wherein R15 and R16 each independently represents a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, and a substituted or unsubstituted aralkyl group; , R18, R19 and R20 are each independently a hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted aralkyl. Represents a group selected from the group consisting of groups.)
According to the third aspect of the present invention, an image formation in which the electrophotographic photosensitive member is injected and charged by applying a charging member voltage arranged in contact with the electrophotographic photosensitive member having a structure in which a photosensitive layer and a surface protective layer are sequentially laminated is applied. In the apparatus, the surface protective layer of the electrophotographic photoreceptor contains a conductive metal oxide, and the photosensitive layer or the surface protective layer is added to the naphthalenecarboxylic acid derivative of the formula (1) or the formula (1-2). Further, by containing a naphthalenecarboxylic acid derivative represented by the formula (1-3), an image forming apparatus having further gas resistance and wear resistance can be provided.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the electrophotographic photosensitive member is injected and charged only with a positive DC voltage.

  According to the fourth aspect of the present invention, it is possible to provide an image forming apparatus having an electrophotographic photosensitive member that can be positively injected and charged only with a DC voltage.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the conductive metal oxide is a titanium oxide-based metal oxide.

  According to the invention described in claim 5, since the conductive metal oxide is a titanium oxide-based metal oxide, image formation capable of preventing scratches, image blurring and filming on the surface of the injection layer in repeated use. An apparatus can be provided.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, the charging member is a magnetic brush charger including a magnetic brush made of magnetic particles.

  According to the sixth aspect of the present invention, since the charging member is a magnetic brush charger including a magnetic brush made of magnetic particles, a cleanerless image forming apparatus can be provided.

  According to a seventh aspect of the present invention, in the invention according to any one of the first to sixth aspects, the photosensitive layer is a multilayer electrophotographic photosensitive member comprising a charge generation layer and a charge transport layer. .

  According to the invention described in claim 7, since the photosensitive layer is a laminated electrophotographic photosensitive member comprising a charge generation layer and a charge transport layer, an electrophotography having excellent stability when repeatedly used with positive charge. An image forming apparatus having a photoreceptor can be provided.

The invention according to an eighth aspect is the invention according to any one of the first to seventh aspects, wherein the volume resistance of the surface protective layer is 10 ^{9 to} 10 ¹² Ω · cm.

According to the invention described in claim 8, by setting the volume resistance of the surface protective layer to 10 ^{9 to} 10 ¹² Ω · cm, image blurring is prevented, and generation of white spot images due to poor charge injection during charging is prevented. be able to.

  The invention according to claim 9 is the invention according to any one of claims 1 to 8, wherein the charge generating material contained in the photosensitive layer is titanyl phthalocyanine.

  According to the invention described in claim 9, by using titanyl phthalocyanine as the charge generation material contained in the photosensitive layer, it is possible to make the photosensitive layer with high sensitivity, and to further reduce the size and speed of the electrophotographic apparatus. More can be achieved.

  The invention according to claim 10 is the invention according to any one of claims 1 to 8, wherein the charge generating material contained in the photosensitive layer has a diffraction peak (±±) of Bragg angle 2θ with respect to the characteristic X-ray of CuKα. 0.2 °) titanyl phthalocyanine having a maximum diffraction peak at 27.2 °.

  According to the tenth aspect of the present invention, the charge generation material contained in the photosensitive layer is a diffraction peak having a Bragg angle 2θ (± 0.2 °) with respect to the characteristic X-ray of CuKα, and a maximum diffraction peak at 27.2 °. By using titanyl phthalocyanine having the above, particularly excellent sensitivity characteristics can be exhibited.

  The invention according to claim 11 is the invention according to claim 9 or 10, wherein the titanyl phthalocyanine is at least 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray of CuKα. It has a maximum diffraction peak, further has main peaks at 9.4 °, 9.6 °, and 24.0 °, and has a peak at 7.3 ° as the lowest diffraction peak, It is characterized by being a titanyl phthalocyanine crystal having no peak between a peak at 3 ° and a peak at 9.4 °, and further having no peak at 26.3 °.

  According to the eleventh aspect of the present invention, titanyl phthalocyanine has a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray of CuKα. It has major peaks at 4 °, 9.6 °, and 24.0 °, and has a peak at 7.3 ° as the lowest diffraction peak, and the peak at 7.3 ° and 9.4 °. By using a titanyl phthalocyanine crystal that does not have a peak between 26.3 ° and does not have a peak at 26.3 °, it does not lose high sensitivity and does not cause a decrease in chargeability even after repeated use. An image forming apparatus having the electrophotographic photosensitive member can be obtained.

  The invention according to a twelfth aspect is characterized in that, in the invention according to any one of the ninth to eleventh aspects, an average particle size of the titanyl phthalocyanine is 0.60 μm or less.

  According to the invention described in claim 12, it is possible to obtain a stable electrophotographic photosensitive member that does not cause deterioration in chargeability even if it is repeatedly used without losing high sensitivity, and further, the background dirt property can be remarkably improved. An image forming apparatus can be obtained.

  The invention according to claim 13 is the image forming method used in the image forming apparatus according to any one of claims 1 to 12, wherein an electrostatic latent image is formed on the electrophotographic photosensitive member by at least charging and image exposure. The image forming method is achieved by the reversal development method of the developing means.

  According to the thirteenth aspect of the present invention, since the developing means is a reversal developing method, an image forming apparatus with little background stain can be provided.

  According to a fourteenth aspect of the present invention, there is provided a process cartridge for an image forming apparatus, which is detachable from the apparatus main body, and includes at least an electrophotographic photosensitive member, a charging unit, a developing unit, and a cleaning unit. This is achieved by a process cartridge for an image forming apparatus used in the image forming apparatus according to any one of Items 1 to 12.

  According to the fourteenth aspect of the present invention, it is possible to obtain a process cartridge in which the electrophotographic photosensitive member, the charging unit, the developing unit, and the cleaning unit are integrally supported and can be attached to and detached from the apparatus main body. An image forming apparatus that can be easily attached and detached can be provided.

  According to the present invention, in an image forming apparatus for injecting and charging an electrophotographic photosensitive member by applying a charging member voltage disposed in contact with the electrophotographic photosensitive member having a structure in which a photosensitive layer and a surface protective layer are sequentially laminated, The surface protective layer of the photoreceptor contains a conductive metal oxide, and the photosensitive layer or the surface protective layer contains a naphthalenecarboxylic acid derivative of the formula (1) or a naphthalenecarboxylic acid derivative of the formula (1-2). Accordingly, it is possible to provide an image forming apparatus having an electrophotographic photosensitive member that can be charged by injection even in positive charging and has high sensitivity and low residual potential. Furthermore, the photosensitive layer or the surface protective layer contains a naphthalenecarboxylic acid derivative represented by the formula (1-3) in addition to the naphthalenecarboxylic acid derivative of the formula (1) or the formula (1-2). Further, it is possible to provide an image forming apparatus having further gas resistance and wear resistance.

  The best mode for carrying out the present invention will be described below with reference to the drawings. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description is an example of the best mode of the present invention, and does not limit the scope of the claims.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this.

The present invention
(1) In an image forming apparatus for injecting and charging an electrophotographic photosensitive member by applying a charging member voltage placed in contact with the electrophotographic photosensitive member having a structure in which a photosensitive layer and a surface protective layer are sequentially laminated, The surface protective layer contains a conductive metal oxide, and the photosensitive layer or the surface protective layer contains a naphthalenecarboxylic acid derivative of the formula (1),

「式中、Ｒ１、Ｒ２は、それぞれ独立に水素原子、置換又は無置換のアルキル基、置換又は無置換のシクロアルキル基、置換又は無置換のアラルキル基からなる群より選ばれる基を表し、Ｒ３、Ｒ４、Ｒ５、Ｒ６、Ｒ７、Ｒ８、Ｒ９、Ｒ１０はそれぞれ独立に水素原子、ハロゲン原子、シアノ基、ニトロ基、アミノ基、水酸基、置換又は無置換のアルキル基、置換又は無置換のシクロアルキル基、置換又は無置換のアラルキル基からなる群より選ばれる基を表す。」
（２）導電性支持体上に少なくとも感光層及び表面保護層を順次積層した構成を持つ電子写真用感光体と、該電子写真感光体に接触配置される帯電部材とを有し、該帯電部材に電圧を印加することにより該電子写真感光体を注入帯電する画像形成装置において、該電子写真感光体の表面保護層が、導電性金属酸化物を含有し、且つ感光層又は表面保護層が式（１−２）のナフタレンカルボン酸誘導体を含有すること、

"Wherein R1 and R2 each independently represents a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aralkyl group, and R3 , R4, R5, R6, R7, R8, R9, R10 are each independently a hydrogen atom, a halogen atom, a cyano group, a nitro group, an amino group, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group. Represents a group selected from the group consisting of a group, a substituted or unsubstituted aralkyl group.
(2) an electrophotographic photoreceptor having a structure in which at least a photosensitive layer and a surface protective layer are sequentially laminated on a conductive support; and a charging member disposed in contact with the electrophotographic photoreceptor, the charging member In the image forming apparatus for injecting and charging the electrophotographic photosensitive member by applying a voltage to the electrophotographic photosensitive member, the surface protective layer of the electrophotographic photosensitive member contains a conductive metal oxide, and the photosensitive layer or the surface protective layer is of the formula Containing the naphthalenecarboxylic acid derivative of (1-2),

（式中、Ｒ１、Ｒ２は、それぞれ独立に水素原子、置換又は無置換のアルキル基、置換又は無置換のシクロアルキル基、置換又は無置換のアラルキル基からなる群より選ばれる基を表し、Ｒ３、Ｒ４、Ｒ５、Ｒ６、Ｒ７、Ｒ８、Ｒ９、Ｒ１０、Ｒ１１、Ｒ１２、Ｒ１３、Ｒ１４はそれぞれ独立に水素原子、ハロゲン原子、シアノ基、ニトロ基、アミノ基、水酸基、置換又は無置換のアルキル基、置換又は無置換のシクロアルキル基、置換又は無置換のアラルキル基からなる群より選ばれる基を表し、ｎは繰り返し単位であり、１から１００までの整数を表す。）
（３）前記ナフタレンカルボン酸誘導体に加えて、さらに式（１−３）で表されるナフタレンカルボン酸誘導体を含有すること、

Wherein R 1 and R 2 each independently represent a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aralkyl group, and R 3 , R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14 are each independently a hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, substituted or unsubstituted alkyl group Represents a group selected from the group consisting of a substituted or unsubstituted cycloalkyl group and a substituted or unsubstituted aralkyl group, and n is a repeating unit and represents an integer of 1 to 100.)
(3) In addition to the naphthalenecarboxylic acid derivative, further containing a naphthalenecarboxylic acid derivative represented by the formula (1-3),

（式中、Ｒ１5、Ｒ16は、それぞれ独立に水素原子、置換又は無置換のアルキル基、置換又は無置換のシクロアルキル基、置換又は無置換のアラルキル基からなる群より選ばれる基を表し、Ｒ17、Ｒ18、Ｒ19、Ｒ20はそれぞれ独立に水素原子、ハロゲン原子、シアノ基、ニトロ基、アミノ基、水酸基、置換又は無置換のアルキル基、置換又は無置換のシクロアルキル基、置換又は無置換のアラルキル基からなる群より選ばれる基を表す。）
（４）電子写真感光体を正の直流電圧のみで注入帯電させること、
（５）導電性金属酸化物が酸化チタン系金属酸化物であること、
（６）帯電部材が磁性粒子からなる磁気ブラシを備えた磁気ブラシ帯電器であること、
（７）感光層が電荷発生層、電荷輸送層からなる積層型電子写真感光体であること、
（８）電子写真感光体の表面保護層の体積抵抗が１０^９乃至１０^１２Ω・ｃｍであること、
（９）感光層に含有される電荷発生物質がチタニルフタロシアニンであること、
（１０）感光層に含有される電荷発生物質が、ＣｕＫαの特性Ｘ線に対するブラッグ角２θの回折ピーク（±０．２゜）として少なくとも２７．２゜に最大回折ピークを有するチタニルフタロシアニンであること、
（１１）チタニルフタロシアニンが、ＣｕＫαの特性Ｘ線に対するブラッグ角２θの回折ピーク（±０．２゜）として少なくとも２７．２゜に最大回折ピークを有し、更に９．４゜、９．６゜、２４．０゜に主要なピークを有し、最も低角側の回折ピークとして７．３゜にピークを有し、該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°にピークを有さないチタニルフタロシアニン結晶であること、
（１２）チタニルフタロシアニンの平均粒子サイズが０．６０μｍ以下であること、
（１３）現像手段が反転現像方式であること、
（１４）電子写真感光体、帯電手段、現像手段、クリーニング手段が一体に支持され装置本体に着脱自在できるプロセスカートリッジであること、
によって構成される。

Wherein R15 and R16 each independently represents a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, and a substituted or unsubstituted aralkyl group; , R18, R19 and R20 are each independently a hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted aralkyl. Represents a group selected from the group consisting of groups.)
(4) Injecting and charging the electrophotographic photosensitive member only with a positive DC voltage;
(5) The conductive metal oxide is a titanium oxide-based metal oxide,
(6) The charging member is a magnetic brush charger provided with a magnetic brush made of magnetic particles,
(7) The photosensitive layer is a multilayer electrophotographic photoreceptor comprising a charge generation layer and a charge transport layer,
(8) The volume resistance of the surface protective layer of the electrophotographic photosensitive member is 10 ^{9 to} 10 ¹² Ω · cm,
(9) the charge generating material contained in the photosensitive layer is titanyl phthalocyanine;
(10) The charge generating material contained in the photosensitive layer is titanyl phthalocyanine having a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray of CuKα. ,
(11) Titanylphthalocyanine has a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray of CuKα, and further 9.4 ° and 9.6 °. , Having a main peak at 24.0 °, a peak at 7.3 ° as the lowest diffraction peak, and a peak between the 7.3 ° peak and the 9.4 ° peak. A titanyl phthalocyanine crystal that does not have a peak at 26.3 °.
(12) The average particle size of titanyl phthalocyanine is 0.60 μm or less,
(13) The developing means is a reversal developing method,
(14) a process cartridge that is integrally supported by an electrophotographic photosensitive member, a charging unit, a developing unit, and a cleaning unit, and is detachable from the apparatus main body;
Consists of.

  The present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view of an electrophotographic apparatus of the present invention.

  In the figure, reference numeral 11 denotes an electrophotographic photoreceptor used in the present invention. First, the photosensitive member 11 is charged by injection by the charging device 12. After the photosensitive member is charged, the image exposure 13 is received, and an electric charge is generated in the exposed portion, and an electrostatic latent image is formed on the surface of the photosensitive member. After an electrostatic latent image is formed on the surface of the photoreceptor, the toner image is formed by contacting the developer via the developing roller 14. The toner image formed on the surface of the photoreceptor is transferred to the transfer member 15 such as paper by the transfer roller 16 and passes through the fixing unit 19 to become a hard copy. Residual toner on the electrophotographic photoreceptor 11 is removed by the cleaning unit 17, and the residual charge is removed by the charge eliminating lamp 18, and the process proceeds to the next electrophotographic cycle. The electrophotographic apparatus of the present invention may constitute a process cartridge in which units such as a charging unit, a developing unit, and a cleaning unit are integrated. Installation and removal are simplified by using a process cartridge.

  The electrophotographic process using the present image forming method and the photoreceptor is not limited to the above example, and is any process that forms an electrostatic latent image by at least charging and exposure. It doesn't matter. In particular, in this image forming method, the toner transfer efficiency is improved and the toner remaining after the transfer is cleanerless without using a cleaning unit and collected by a charging device or a developing device. Desirable because of low load.

  Next, the charging method in the present invention will be described. The charging method of the present invention is a contact charging method that does not involve a discharge phenomenon. In other words, this is a charge injection charging method capable of charging the photoconductor with a potential corresponding to the voltage applied to the contact charging device. Since this method does not involve discharge, less ozone and nitrogen oxide are generated, and the applied voltage for charging the photosensitive member is lower than that of the process using the conventional contact charging method, so that energy is saved. .

  The photoreceptor to be used is provided with a surface protective layer having a function of a charge injection layer on the outermost layer described above. The charge injection layer serves as a so-called capacitor electrode. When a conductive contact charging member is brought into contact with this electrode and a voltage is applied, charge can be injected. In the absence of such a charge injection layer, there is nothing that can serve as an electrode on the surface of the photoreceptor, and sufficient charge injection cannot be performed.

  By providing the charge injection layer on the surface of the photosensitive layer, a uniform charge sheet can be formed on the surface of the photosensitive layer below the charge injection layer. The charge injection layer is required to have a characteristic that a charge applied by a contact charging device is quickly transferred to the surface layer of the photosensitive layer to form a uniform charge sheet.

  In order to form a uniform charge sheet, both the charge injection layer and the contact charging device must have characteristics such as uniform contact property, nip, contact resistance, and volume resistivity of the member. Must be set.

  As the contact charging method, there is an example as shown in FIG.

  2 (I) is a magnetic brush charging method, FIG. 2 (II) is a (conductive) brush charging method, FIG. 2 (III) is a roller charging method using a conductive soft roller, and FIG. 2 (IV) is fixed. The charging method of the formula (blade type), FIG. 2 (V) is a belt type charging method using two rollers and a conductive belt.

  In order to charge the photoconductor uniformly without discharge, ensure the necessary nip with the photoconductor with the appropriate applied voltage, reduce the gap between the photoconductor and the charger as much as possible, and make the contact as dense as possible. There is a need to.

  In the magnetic brush charging method of FIG. 2 (I), a spherical roller of about 20 to 150 μm is formed on a magnetic roller formed by covering a magnet roller having S and N pole magnets alternately arranged with a sleeve of a nonmagnetic material such as aluminum or bakelite. Alternatively, magnetic particles such as almost spherical ferrite, manganese oxide, and gamma ferric oxide, or magnetic particles coated on them for the purpose of improving fluidity, such as polyester resin and fluororesin, and a protective layer, are about 1 to 5 mm. A layer formed by sucking to a thickness is used.

The resistance value of the magnetic fine particles is usually in the range of 10 ⁵ Ω · cm to 10 ¹⁰ Ω · cm, and the lower the resistance, the better the charge injection property. 10 ⁶ Ω · cm to 10 ⁹ Ω · cm is particularly preferable. It is also possible to form a cleaningless process by using a magnetic brush. If the resistance value of the magnetic fine particles is less than 10 ⁵ Ω · cm, the image flow under high temperature and high humidity tends to cause white spots under low temperature and low humidity when it exceeds 10 ¹⁰ Ω · cm.

  The conductive brush charging method shown in FIG. 2 (II) is a conductive treatment of fibers such as rayon, acrylic, polypropylene, polyester, and polyacrylonitrile with carbon, copper sulfide, etc., and conductive properties such as zinc oxide, tin oxide, and titanium oxide. It is made into a brush using a member that is spun with a fiber kneaded with a filler or knitted with a metal yarn.

  In addition, carbon fibers or activated carbon fibers obtained by firing the fibers in an inert gas atmosphere can be used.

The resistance of the member of the contact charging device is preferably in the range of 10 ² Ω · cm to 10 ¹⁰ Ω · cm.

Carbon fiber and activated carbon fiber can freely change the deposition resistivity at the firing temperature. When the carbon component is 90% or more, the resistance is as extremely low as about 10 ² Ω · cm. Accordingly, there is a risk of electric discharge destruction when the photoconductor has a pinhole, but there is no problem when it is used at a low voltage. Usually, a protective resistor of about 100 KΩ to 5 MΩ is inserted in series with the voltage supply source.

The (soft) roller charging method of FIG. 2 (III) is suitable for increasing the nip with the photoconductor and improving the adhesion with the photoconductor. The soft roller is made of soft rubber, soft foam (urethane sponge, foam, etc.), and the surface layer or the entire layer is subjected to a conductive treatment. As the conductive process material SnO ₂ and _TiO 2, ZnO _2, conductive fillers such as carbon black, carbon fibers, and the like electrically conductive fibers such as activated carbon fibers.

  The fixed (blade type) charging method in FIG. 2 (IV) is a method of charging in such a manner that the photosensitive member is rubbed, and the above-described members are almost usable.

  Constitution includes, for example, elastic members such as sponges and foams, finely woven carbon fibers and activated carbon fibers as charging members (produced by Unitika, Toho Rayon, Beslon, etc., FW210 and 310 in the Toho Rayon example) In such a form as to cover the surface, charging is performed by contacting the photosensitive member.

  The belt-type charging device in FIG. 2 (V) is a good means for earning a nip with the photoreceptor. As materials that can be used, members described in the conductive brush charging method and the roller charging method can be used.

  The wider the nip necessary for contact with the photoreceptor, the better. However, it is usually sufficient that the nip is about 3 mm to 10 mm or more, and it is desirable that the contact with the photoreceptor is evenly and uniformly.

When the various members described above are used as the charging member, the volume resistivity is desirably 10 ² Ω · cm to 10 ¹⁰ Ω · cm, and preferably 10 ⁸ Ω · cm or less. The higher the resistance, the lower the charge injection property. If it is too low, there is no problem with the charge injection property, but if there is a pinhole in the photoreceptor, there is a risk that a power supply break or horizontal black streaks will occur on the image. Usually, since the charging level of the photoconductor is about 500 to 900 V, there is little risk of electric discharge destruction, and even if ozone is generated, there is very little, so the practical effect is small.

  The photoreceptor of the present invention can be used in a general electrophotographic process including a charge injection charging method.

Next, the details of the electrophotographic photoreceptor of the present invention will be described.
3 to 5 are schematic cross-sectional views of the electrophotographic photoreceptor of the present invention. FIG. 3 shows a structure in which a photosensitive layer and a surface protective layer are provided on a conductive substrate. FIGS. FIG. 4 shows an example of the structure of another electrophotographic photoreceptor that can be used. FIG. 4 shows a function-separated type in which the photosensitive layer is composed of a charge generation layer (CGL) and a charge transport layer (CTL). Shows a subbing layer inserted between CGL and CTL of a conductive substrate and a function-separated type photosensitive layer. In addition, as long as it has at least the photosensitive layer and the surface protective layer on the conductive support, the other layers and the types of the photosensitive layers may be arbitrarily combined.

  The surface protective layer is composed of tin oxide, titanium oxide, TiO, zinc oxide, indium oxide, antimony oxide, conductive metal oxide such as titanium oxide whose surface is conductively treated, polycarbonate, polyester, methacrylic resin, acrylic resin, polyethylene, chloride Thermoplastic resins such as vinyl, vinyl acetate, polystyrene, polyacrylamide, etc., or phenol resin, epoxy resin, polyurethane, alkyd resin, silicon resin, polyvinyl butyral, polyvinyl formal, polyacrylate, phenoxy resin, etc. And a naphthalenecarboxylic acid derivative of the formula (1) or a naphthalenecarboxylic acid derivative of the formula (1-2). The particle size of the conductive metal oxide is preferably 0.3 μm to 1 μm. Although it is preferably 0.3 μm or less from the viewpoint of translucency, toner filming and image flow are likely to occur. If the thickness is 1 μm or more, uniformity as charge injection cannot be obtained, and image blurring occurs. As the surface-conducting titanium oxide, white conductive titanium oxide (ET-500W; manufactured by Ishihara Sangyo Co., Ltd.) treated with a tin oxide-based conductive layer, tin oxide, tin oxide electroconductively treated with antimony oxide (SN-100; Ishihara Sangyo).

「式中、Ｒ１、Ｒ２は、それぞれ独立に水素原子、置換又は無置換のアルキル基、置換又は無置換のシクロアルキル基、置換又は無置換のアラルキル基からなる群より選ばれる基を表し、Ｒ３、Ｒ４、Ｒ５、Ｒ６、Ｒ７、Ｒ８、Ｒ９、Ｒ１０はそれぞれ独立に水素原子、ハロゲン原子、シアノ基、ニトロ基、アミノ基、水酸基、置換又は無置換のアルキル基、置換又は無置換のシクロアルキル基、置換又は無置換のアラルキル基からなる群より選ばれる基を表す。」
式（１）において置換又は無置換のアルキル基としては、炭素数１乃至２５、好ましくは炭素数１乃至１０の炭素原子を有するアルキル基、具体的には、メチル基、エチル基、ｎ−プロピル基、ｎ−ブチル基、ｎ−ペンチル基、ｎ−ヘキシル基、ｎ−ペプチル基、ｎ−オクチル基、ｎ−ノニル基、ｎ−デシル基といった直鎖状のもの、ｉ―プロピル基、ｓ−ブチル基、ｔ−ブチル基、メチルプロピル基、ジメチルプロピル基、エチルプロピル基、ジエチルプロピル基、メチルブチル基、ジメチルブチル基、メチルペンチル基、ジメチルペンチル基、メチルヘキシル基、ジメチルヘキシル基等の分岐状のもの、アルコキシアルキル基、モノアルキルアミノアルキル基、ジアルキルアミノアルキル基、ハロゲン置換アルキル基、アルキルカルボニルアルキル基、カルボキシアルキル基、アルカノイルオキシアルキル基、アミノアルキル基、エステル化されていてもよいカルボキシル基で置換されたアルキル基、シアノ基で置換されたアルキル基等が例示できる。なお、これらの置換基の置換位置については特に限定されず、上記置換又は無置換のアルキル基の炭素原子の一部がヘテロ原子（Ｎ、Ｏ、Ｓ等）に置換された基も置換されたアルキル基に含まれる。

"Wherein R1 and R2 each independently represents a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aralkyl group, and R3 , R4, R5, R6, R7, R8, R9, R10 are each independently a hydrogen atom, a halogen atom, a cyano group, a nitro group, an amino group, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group. Represents a group selected from the group consisting of a group, a substituted or unsubstituted aralkyl group.
In the formula (1), the substituted or unsubstituted alkyl group is an alkyl group having 1 to 25 carbon atoms, preferably 1 to 10 carbon atoms, specifically a methyl group, an ethyl group, or n-propyl. A linear group such as a group, n-butyl group, n-pentyl group, n-hexyl group, n-peptyl group, n-octyl group, n-nonyl group, n-decyl group, i-propyl group, s- Branched butyl group, t-butyl group, methylpropyl group, dimethylpropyl group, ethylpropyl group, diethylpropyl group, methylbutyl group, dimethylbutyl group, methylpentyl group, dimethylpentyl group, methylhexyl group, dimethylhexyl group, etc. An alkoxyalkyl group, a monoalkylaminoalkyl group, a dialkylaminoalkyl group, a halogen-substituted alkyl group, an alkylcarbonyl Alkyl group, carboxyalkyl group, alkanoyloxyalkyl group, aminoalkyl group, esterified optionally alkyl group substituted with a carboxyl group which have an alkyl group substituted by a cyano group are exemplified. The substitution position of these substituents is not particularly limited, and a group in which a part of carbon atoms of the substituted or unsubstituted alkyl group is substituted with a hetero atom (N, O, S, etc.) is also substituted. Included in the alkyl group.

  As the substituted or unsubstituted cycloalkyl group, a cycloalkyl ring having 3 to 25 carbon atoms, preferably 3 to 10 carbon atoms, specifically, a homogenous ring from cyclopropane to cyclodecane, methylcyclopentane , Having an alkyl substituent such as dimethylcyclopentane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, tetramethylcyclohexane, ethylcyclohexane, diethylcyclohexane, t-butylcyclohexane, alkoxyalkyl group, monoalkylaminoalkyl group, dialkylaminoalkyl Group, halogen-substituted alkyl group, alkoxycarbonylalkyl group, carboxyalkyl group, alkanoyloxyalkyl group, aminoalkyl group, halogen atom, amino group, esterification Is a carboxyl group which may, cycloalkyl group substituted by a cyano group and the like. The substitution position of these substituents is not particularly limited, and a group in which a part of carbon atoms of the substituted or unsubstituted cycloalkyl group is substituted with a hetero atom (N, O, S, etc.) is also substituted. It is included in the cycloalkyl group.

  Examples of the substituted or unsubstituted aralkyl group include groups in which an aromatic ring is substituted on the above-described substituted or unsubstituted alkyl group, and an aralkyl group having 6 to 14 carbon atoms is preferable. More specifically, benzyl group, perfluorophenylethyl group, 1-phenylethyl group, 2-phenylethyl group, terphenylethyl group, dimethylphenylethyl group, diethylphenylethyl group, t-butylphenylethyl group, 3- Examples thereof include a phenylpropyl group, a 4-phenylbutyl group, a 5-phenylpentyl group, a 6-phenylhexyl group, a benzhydryl group, and a trityl group.

  The following method can be illustrated as a manufacturing method of the naphthalenecarboxylic acid derivative represented by Formula (1).

  It can be obtained by reacting naphthalenecarboxylic acid or its anhydride with amines to monoimidize, adjusting the pH of naphthalenecarboxylic acid or its anhydride with a buffer and reacting with diamines, and the like. Monoimidization is carried out without solvent or in the presence of a solvent. The solvent is not particularly limited, but it does not react with raw materials or products such as benzene, toluene, xylene, chloronaphthalene, acetic acid, pyridine, methylpyridine, dimethylformamide, dimethylacetamide, dimethylethyleneurea, dimethylsulfoxide, and the like. It is good to use what can be made to react at the temperature of thru | or 250 degreeC. For pH adjustment, a buffer solution prepared by mixing a basic aqueous solution such as lithium hydroxide or potassium hydroxide with an acid such as phosphoric acid is used. Carboxylic acid derivative dehydration reaction obtained by reacting carboxylic acid with amines or diamines is carried out in the absence of a solvent or in the presence of a solvent. Although there is no restriction | limiting in particular as a solvent, It is good to use what reacts at the temperature of 50 to 250 degreeC, without reacting with raw materials and products, such as benzene, toluene, chloronaphthalene, bromonaphthalene, and acetic anhydride. Any reaction may be carried out without a catalyst or in the presence of a catalyst, and is not particularly limited. For example, molecular sieves, benzenesulfonic acid, p-toluenesulfonic acid and the like can be used as a dehydrating agent.

  More specifically, naphthalenecarboxylic acid derivatives represented by the formulas (4) to (9) are preferable in terms of high quality images.

なお、式（４）乃至（９）中、Ｍｅはメチル基を示す。

In formulas (4) to (9), Me represents a methyl group.

（式中、Ｒ１、Ｒ２は、それぞれ独立に水素原子、置換又は無置換のアルキル基、置換又は無置換のシクロアルキル基、置換又は無置換のアラルキル基からなる群より選ばれる基を表し、Ｒ３、Ｒ４、Ｒ５、Ｒ６、Ｒ７、Ｒ８、Ｒ９、Ｒ１０、Ｒ１１、Ｒ１２、Ｒ１３、Ｒ１４はそれぞれ独立に水素原子、ハロゲン原子、シアノ基、ニトロ基、アミノ基、水酸基、置換又は無置換のアルキル基、置換又は無置換のシクロアルキル基、置換又は無置換のアラルキル基からなる群より選ばれる基を表し、ｎは繰り返し単位であり、１から１００までの整数を表す。）
該置換又は無置換のアルキル基としては、炭素数１〜２５、好ましくは炭素数１〜１０の炭素原子を有するアルキル基、具体的には、メチル基、エチル基、ｎ−プロピル基、ｎ−ブチル基、ｎ−ペンチル基、ｎ−ヘキシル基、ｎ−ペプチル基、ｎ−オクチル基、ｎ−ノニル基、ｎ−デシル基といった直鎖状のもの、ｉ―プロピル基、ｓ−ブチル基、ｔ−ブチル基、メチルプロピル基、ジメチルプロピル基、エチルプロピル基、ジエチルプロピル基、メチルブチル基、ジメチルブチル基、メチルペンチル基、ジメチルペンチル基、メチルヘキシル基、ジメチルヘキシル基等の分岐状のもの、アルコキシアルキル基、モノアルキルアミノアルキル基、ジアルキルアミノアルキル基、ハロゲン置換アルキル基、アルキルカルボニルアルキル基、カルボキシアルキル基、アルカノイルオキシアルキル基、アミノアルキル基、エステル化されていてもよいカルボキシル基で置換されたアルキル基、シアノ基で置換されたアルキル基等が例示できる。なお、これらの置換基の置換位置については特に限定されず、上記置換又は無置換のアルキル基の炭素原子の一部がヘテロ原子（Ｎ、Ｏ、Ｓ等）に置換された基も置換されたアルキル基に含まれる。

Wherein R 1 and R 2 each independently represent a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aralkyl group, and R 3 , R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14 are each independently a hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, substituted or unsubstituted alkyl group Represents a group selected from the group consisting of a substituted or unsubstituted cycloalkyl group and a substituted or unsubstituted aralkyl group, and n is a repeating unit and represents an integer of 1 to 100.)
The substituted or unsubstituted alkyl group is an alkyl group having 1 to 25 carbon atoms, preferably 1 to 10 carbon atoms, specifically a methyl group, an ethyl group, an n-propyl group, an n- Straight chain such as butyl group, n-pentyl group, n-hexyl group, n-peptyl group, n-octyl group, n-nonyl group, n-decyl group, i-propyl group, s-butyl group, t -Branched group such as butyl group, methylpropyl group, dimethylpropyl group, ethylpropyl group, diethylpropyl group, methylbutyl group, dimethylbutyl group, methylpentyl group, dimethylpentyl group, methylhexyl group, dimethylhexyl group, alkoxy Alkyl group, monoalkylaminoalkyl group, dialkylaminoalkyl group, halogen-substituted alkyl group, alkylcarbonylalkyl group, Kishiarukiru group, alkanoyloxy group, an aminoalkyl group, esterified optionally alkyl group substituted with a carboxyl group which have an alkyl group substituted by a cyano group are exemplified. The substitution position of these substituents is not particularly limited, and a group in which a part of carbon atoms of the substituted or unsubstituted alkyl group is substituted with a hetero atom (N, O, S, etc.) is also substituted. Included in the alkyl group.

  The substituted or unsubstituted cycloalkyl group includes a cycloalkyl ring having 3 to 25 carbon atoms, preferably 3 to 10 carbon atoms, specifically, a homocyclic ring from cyclopropane to cyclodecane, methylcyclo Those having an alkyl substituent such as pentane, dimethylcyclopentane, methylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, tetramethylcyclohexane, ethylcyclohexane, diethylcyclohexane, t-butylcyclohexane, alkoxyalkyl groups, monoalkylaminoalkyl groups, dialkylamino Alkyl group, halogen-substituted alkyl group, alkoxycarbonylalkyl group, carboxyalkyl group, alkanoyloxyalkyl group, aminoalkyl group, halogen atom, amino group, esterified Which may be a carboxyl group, a cycloalkyl group substituted by a cyano group and the like. The substitution position of these substituents is not particularly limited, and a group in which a part of carbon atoms of the substituted or unsubstituted cycloalkyl group is substituted with a hetero atom (N, O, S, etc.) is also substituted. It is included in the cycloalkyl group.

  Examples of the substituted or unsubstituted aralkyl group include groups in which an aromatic ring is substituted on the above-described substituted or unsubstituted alkyl group, and an aralkyl group having 6 to 14 carbon atoms is preferable. More specifically, benzyl group, perfluorophenylethyl group, 1-phenylethyl group, 2-phenylethyl group, terphenylethyl group, dimethylphenylethyl group, diethylphenylethyl group, t-butylphenylethyl group, 3- Examples thereof include a phenylpropyl group, a 4-phenylbutyl group, a 5-phenylpentyl group, a 6-phenylhexyl group, a benzhydryl group, and a trityl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  Examples of the production method of the naphthalenecarboxylic acid derivative (charge transport material) represented by the formula (1-2) can be exemplified by the following two synthesis methods.

一般式（１−２）で表されるナフタレンカルボン酸誘導体（電荷輸送物質）の繰り返し単位ｎは１から１００の整数である。

The repeating unit n of the naphthalenecarboxylic acid derivative (charge transport material) represented by the general formula (1-2) is an integer of 1 to 100.

  The repeating unit n is determined from the weight average molecular weight (Mw). That is, the compound exists with a distribution in molecular weight. When n exceeds 100, the molecular weight of the compound increases and the solubility in various solvents decreases, so 100 or less is preferable.

  On the other hand, when n is 1, for example, it is a trimer of naphthalene carboxylic acid, but excellent electron transfer characteristics can be obtained even for oligomers by appropriately selecting substituents for R1 and R2. In this way, a wide range of naphthalenecarboxylic acid derivatives from oligomers to polymers are synthesized depending on the number of repeating units n.

  In the range where the molecular weight of the oligomer region is small, monodispersed compounds can be obtained by stepwise synthesis. In the case of a compound having a large molecular weight, a compound having a distribution in molecular weight is obtained.

  More specifically, examples of the charge transport material represented by the formula (1-2) include the following compounds.

（ただし、いずれも式中、両端の末端基はＭｅ（メチル基）を表す。）
本発明の表面保護層の体積抵抗は、１０^９乃至１０^１２Ω・ｃｍであることが望ましい。１０^９Ω・ｃｍ以下では画像ボケ、１０^１２Ω・ｃｍ以上では帯電持電荷の注入不良による白ポチ画像が発生する。導電性微粒子の含有量は、１０乃至８０重量％の範囲が好ましい。電荷注入層においては、導電性微粒子の分散性向上、接着性あるいは平滑性の向上を目的として、種々の添加剤を加えることができる。特に、分散性の向上に関して、カップリング剤の添加あるいはレベリング剤により導電性微粒子の表面処理を行なうことが非常に有効である。また同様に、分散性の向上の点よりバインダー樹脂として硬化型樹脂を用いると更に特性が向上する。硬化型樹脂を電荷注入層に用いる場合には、導電性微粒子を硬化型モノマーまたはオリゴマーの溶液中に分散した塗工液を感光層上に塗布、成膜後、熱または光照射によって該塗布膜を硬化させて電荷注入層とする。表面保護層の膜厚は、０．５乃至１０μｍであることが望ましい。

(However, in both formulas, the terminal groups at both ends represent Me (methyl group).)
The volume resistance of the surface protective layer of the present invention is desirably 10 ^{9 to} 10 ¹² Ω · cm. If it is 10 ⁹ Ω · cm or less, the image is blurred, and if it is 10 ¹² Ω · cm or more, a white spot image is generated due to poor injection of charged charge. The content of the conductive fine particles is preferably in the range of 10 to 80% by weight. In the charge injection layer, various additives can be added for the purpose of improving the dispersibility of the conductive fine particles and improving the adhesion or smoothness. In particular, for improving dispersibility, it is very effective to add a coupling agent or to treat the surface of the conductive fine particles with a leveling agent. Similarly, when a curable resin is used as the binder resin from the viewpoint of improving dispersibility, the characteristics are further improved. When a curable resin is used for the charge injection layer, a coating solution in which conductive fine particles are dispersed in a solution of a curable monomer or oligomer is applied onto the photosensitive layer, and after coating, the coating film is applied by heat or light irradiation. Is cured into a charge injection layer. The thickness of the surface protective layer is preferably 0.5 to 10 μm.

  When the photosensitive layer is a function-separated type composed of a charge generation layer (CGL) and a charge transport layer (CTL), the charge transport layer is represented by the formula (1) or formula (1-2) as a charge transport material. It is formed by dissolving or dispersing a mixture or copolymer comprising a charge transporting component comprising a naphthalenecarboxylic acid derivative and a binder component as main components in an appropriate solvent, and applying and drying the mixture.

  In the present invention, the naphthalenecarboxylic acid derivative represented by the formula (1-3) can also be added in combination with the naphthalenecarboxylic acid derivative represented by the formula (1) or the formula (1-2).

  Specific examples of the naphthalenecarboxylic acid derivative represented by the formula (1-3) include the following compounds.

（ただし、式中、両端の末端基はＭｅ（メチル基）を表す。）

(However, in the formula, the terminal groups at both ends represent Me (methyl group).)

（ただし、式中、両端の末端基はＭｅ（メチル基）を表す。）
これらの電荷輸送物質の添加量としては特に限定されるものではないが、好ましくは電荷輸送物質全体量に対して１％から５０％程度であり、より好ましくは５％〜３０％である。添加量が１％未満であると膜質改善が軽微で明確な効果が見られず、５０％以上となると電荷輸送能がやや低下する傾向がみられる場合があるからである。

(However, in the formula, the terminal groups at both ends represent Me (methyl group).)
The amount of these charge transport materials to be added is not particularly limited, but is preferably about 1% to 50%, more preferably 5% to 30% with respect to the total amount of the charge transport material. This is because when the addition amount is less than 1%, the film quality improvement is slight and no clear effect is observed, and when the addition amount is 50% or more, the charge transport ability tends to be slightly lowered.

  In the present invention, in addition to the naphthalenecarboxylic acid derivative represented by the above formula (1-3), a known charge transport material, that is, an electron transport material (acceptor) or a hole transport material (donor) is represented by the formula (1) or It can also be used in combination with a naphthalenecarboxylic acid derivative represented by the formula (1-2). Charge transport materials that can be used in combination include an electron transport material and a hole transport material. Examples of the electron transporting material include chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron accepting substances such as nitrodibenzothiophene-5,5-dioxide. These electron transport materials may be used alone or as a mixture of two or more.

  Examples of the polymer compound that can be used as the binder component of the charge transport layer include polystyrene, polyethylene, styrene / acrylonitrile copolymer, styrene / butadiene copolymer, styrene / maleic anhydride copolymer, and ethylene / acetic acid. Vinyl copolymer, polyester, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, Examples include, but are not limited to, thermoplastic or thermosetting resins such as polypropylene, acrylic resin, silicone resin, fluororesin, epoxy resin, melamine resin, urethane resin, phenol resin, and alkyd resin. Not intended to be.

These polymer compounds can be used singly or as a mixture of two or more kinds, or as a copolymer comprising two or more kinds of raw material monomers, and further copolymerized with a charge transport material.
The addition amount of the charge transport material is 40 to 200 parts by weight, preferably about 70 to 150 parts by weight, per 100 parts by weight of the resin component.

  In order to satisfy high sensitivity, the amount of the charge transport component is preferably 70 parts by weight or more with respect to 100 parts by weight of the resin component.

  Examples of the dispersion solvent that can be used in preparing the charge transport layer coating solution include ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone, ethers such as dioxane, tetrahydrofuran, and ethyl cellosolve, toluene, xylene, and the like. Examples thereof include aromatics, esters such as ethyl acetate and butyl acetate. These solvents can be used alone or in combination.

  If necessary, low-molecular compounds such as antioxidants, plasticizers, lubricants and ultraviolet absorbers and leveling agents described later can be added to the charge transport layer. These compounds can be used alone or as a mixture of two or more. The amount of the low molecular compound used is 0.1 to 50 parts by weight, preferably 0.1 to 20 parts by weight based on 100 parts by weight of the polymer compound, and the amount of the leveling agent used is 100 parts by weight of the polymer compound. On the other hand, about 0.001 to 5 parts by weight is appropriate.

  As the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the chain are used. As the coating method, a dipping method, a spray coating method, a ring coating method, a roll coater method, a gravure coating method, a nozzle coating method, a screen printing method, or the like is employed. In particular, spray coating is preferred because it is easy to prevent filler aggregation during coating.

  The thickness of the charge transport layer is suitably about 15 to 50 μm, preferably about 15 to 35 μm, and when resolution is required, 25 μm or less is appropriate.

  The charge generation layer is a layer mainly composed of a charge generation material, and a binder resin may be used as necessary. The charge generating material used in the present invention is not particularly limited, but phthalocyanine pigments are particularly preferable from the viewpoint of various properties necessary for the present invention.

  Among them, as described above, particularly titanyl phthalocyanine having titanium as a central metal makes it possible to make a photosensitive layer with particularly high sensitivity, and it is possible to further reduce the size and speed of an electrophotographic apparatus. . Further, among various crystal forms, titanyl phthalocyanine having a maximum diffraction peak at 27.2 ° with a Bragg angle 2θ exhibits particularly excellent sensitivity characteristics and is used favorably. In particular, it has a maximum diffraction peak at 27.2 ° described in JP-A-2001-19871, and further has main peaks at 9.4 °, 9.6 °, and 24.0 °, In addition, by using titanyl phthalocyanine having a peak at 7.3 ° as the diffraction peak on the lowest angle side and having no peak between the 7.3 ° peak and the 9.4 ° peak, Without losing sensitivity, it is possible to obtain a stable electrophotographic photosensitive member that does not cause a decrease in chargeability even when used repeatedly.

  In addition, by using the titanyl phthalocyanine crystal having an average particle size of 0.60 μm or less, it is possible to obtain a stable electrophotographic photosensitive member that does not cause deterioration in chargeability even after repeated use without losing high sensitivity. The background dirt property can be remarkably improved.

  The binder resin used as necessary for the charge generation layer includes polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, polyarylate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-. Examples thereof include vinyl carbazole and polyacrylamide.

  These binder resins may be used alone or as a mixture of two or more.

  In addition, a polymer charge transport material can be used as the binder resin of the charge generation layer. Furthermore, you may add leveling agents, such as a charge transport substance and silicone oil, as needed.

  As a method for forming the charge generation layer, a casting method from a solution dispersion system is preferable. In order to provide a charge generation layer by a casting method, the above-described charge generation material is dispersed by a ball mill, an attritor, a sand mill or the like using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, butanone together with a binder resin, if necessary. It is sufficient to apply the solution after diluting it appropriately. The coating can be performed by a dip coating method, a spray coating method, a bead coating method, or the like.

  The film thickness of the charge generation layer provided as described above is usually 0.01 μm to 5 μm, preferably 0.1 μm to 2 μm.

  The undercoat layer is provided for the purpose of preventing charge injection from the support side, improving adhesion, preventing moire, improving the coatability of the upper layer, and reducing residual potential. The undercoat layer is mainly composed of a resin, and if necessary, fine powders such as metal oxides, metal sulfides, metal nitrides, etc., which can be exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide, etc. Single or two or more types are appropriately selected and added. High purity titanium oxide is particularly preferable.

  Moreover, you may add an electron transport material and a hole transport material as needed. As the resin used for the undercoat layer, considering that the photosensitive layer on the undercoat layer is applied using a solvent, it is desirable that the resin be highly soluble in general organic solvents. Examples of such a resin include thermoplastic resins such as polyamide, polyester, vinyl chloride-vinyl acetate copolymer, and thermosetting resins such as active hydrogen (—OH group, —NH 2 group, —NH group, etc.). And a thermosetting resin obtained by thermally polymerizing a compound containing a plurality of hydrogen groups and a compound containing a plurality of isocyanate groups and / or a compound containing a plurality of epoxy groups. Examples of the compound containing a plurality of active hydrogens include acrylic resins containing active hydrogen such as polyvinyl butyral, phenoxy resin, phenol resin, polyamide, polyester, and hydroxyethyl methacrylate group. Examples of the compound containing a plurality of isocyanate groups include tolylene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, and prepolymers thereof. Examples of the compound having a plurality of epoxy groups include bisphenol A type epoxy resin. It is done.

  Further, a thermosetting resin obtained by thermally polymerizing an oil-free alkyd resin and an amino resin such as butylated melamine resin, a polyurethane having an unsaturated bond, a resin having an unsaturated bond such as an unsaturated polyester, and a thioxanthone compound A photocurable resin such as a combination with a photopolymerization initiator such as methylbenzyl formate can also be used as the binder resin. These resins are used alone or in combination of two or more. These resins are used by dissolving in an appropriate solvent. When the metal oxide powder is used, it can be dispersed together with a solvent and a binder resin by a conventional method, for example, using a ball mill, a sand mill, an attritor or the like. The undercoat layer is formed on the conductive substrate by roll coating, dip coating, spray coating, nozzle coating, blade coating, or the like. After application, it is dried or cured by a curing process such as drying, heating, or light. The thickness of the undercoat layer is suitably 0.1 to 30 μm, preferably 0.2 to 10 μm. Further, when a metal oxide is added to the undercoat layer, the volume ratio with respect to the binder resin is preferably in the range of 0.5 / 1 to 3/1.

As the conductive support used in the electrophotographic photoreceptor of the present invention, one having a volume resistance of 10 ¹⁰ Ω · cm or less, such as aluminum, nickel, chromium, nichrome, copper, silver, gold, platinum A metal such as iron, an oxide such as tin oxide or indium oxide coated with a film or cylindrical plastic or paper by vapor deposition or sputtering, or a plate such as aluminum, aluminum alloy, nickel or stainless steel, and , Pipes that have been surface-treated by cutting, super-finishing, polishing, etc. can be used after forming them into pipes by methods such as the drawing ironing method, the impact ironing method, the extracted ironing method, the extracted drawing method, and the cutting method. .

  When the photosensitive layer is a single layer type, it is essential to use a naphthalenecarboxylic acid derivative represented by formula (1) or formula (1-2) as a charge transport material as an electron transport material used as a charge transport material. However, in addition to this, it is also possible to exemplify the use of a known electron transport material (acceptor) and hole transport material (donor) as described above in a range not impairing the object of the present invention.

  The amount of the charge transport material added is 40 to 200 parts by weight with respect to 100 parts by weight of the binder resin component, and preferably 70 to 150 parts by weight in terms of obtaining a highly sensitive photoreceptor.

  The film thickness of the single-layer type photosensitive layer is suitably about 15 to 40 μm, preferably about 15 to 30 μm, and when resolution is required, it is preferably 25 μm or less.

  Examples of the coating method for the single-layer type photosensitive layer include dipping method, spray coating method, ring coating method, roll coater method, gravure coating method, nozzle coating method, screen printing method, etc. Spray coating is preferred because it is easy to prevent aggregation.

  Examples of synthesis and examples are shown below.

Synthesis Example 1 Naphthalenecarboxylic Acid Derivative of Formula (4) First Step In a 200 ml four-necked flask, 5.0 g (18.6 mmol) of 1,4,5,8-naphthalenetetracarboxylic dianhydride and 50 ml of DMF are added and heated. Refluxed. To this, a mixture of 2.14 g (18.6 mmol) of 2-aminoheptane and 25 ml of DMF was added dropwise with stirring. After completion of dropping, the mixture was heated to reflux for 6 hours. After completion of the reaction, the container was cooled and concentrated under reduced pressure. Toluene was added to the residue, and the residue was purified by silica gel column chromatography. Furthermore, the recovered product was recrystallized from toluene / hexane to obtain 2.14 g of monoimide A (yield 31.5%).

Second Step A 100 ml four-necked flask was charged with 2.0 g (5.47 mmol) of monoimide A, 0.137 g (2.73 mmol) of hydrazine monohydrate, 10 mg of p-toluenesulfonic acid, and 50 ml of toluene and heated to reflux for 5 hours. . After completion of the reaction, the container was cooled and concentrated under reduced pressure. The residue was purified by silica gel column chromatography. Further, the recovered product was recrystallized from toluene / ethyl acetate to obtain 0.668 g (yield 33.7%) of the compound represented by the formula (4). In mass spectrometry (FD-MS), a peak of M / z = 726 was observed and identified as a target product. In the elemental analysis, calculated values were 69.41% carbon, 5.27% hydrogen, and 7.71% nitrogen, and the measured values were 69.52% carbon, 5.09% hydrogen, and 7.93% nitrogen.

Synthesis Example 2 Naphthalenecarboxylic Acid Derivative of Formula (5) First Step In a 200 ml four-necked flask, 10 g (37.3 mmol) of 1,4,5,8-naphthalenetetracarboxylic dianhydride and hydrazine monohydrate 0.931 g (18.6 mmol), 20 mg of p-toluenesulfonic acid, and 100 ml of toluene were added and heated to reflux for 5 hours. After completion of the reaction, the container was cooled and concentrated under reduced pressure. The residue was purified by silica gel column chromatography. The recovered product was recrystallized from toluene / ethyl acetate to obtain 2.84 g of dimer C (yield 28.7%).

Second Step In a 100 ml four-necked flask, 2.5 g (4.67 mmol) of both-bodies C and 30 ml of DMF were placed and heated to reflux. To this, a mixture of 0.278 g (4.67 mmol) of 2-aminopropane and 10 ml of DMF was added dropwise with stirring. After completion of dropping, the mixture was heated to reflux for 6 hours. After completion of the reaction, the reaction vessel was cooled and concentrated under reduced pressure. Toluene was added to the residue and the residue was purified by silica gel column chromatography to obtain 0.556 g (yield 38.5%) of monoimide C.

Third Step In a 50 ml four-necked flask, 0.50 g (1.62 mmol) of monoimide C and 10 ml of DMF were placed and heated to reflux. To this, a mixture of 2-aminoheptane 0.186 g (1.62 mmol) and DMF 5 ml was added dropwise with stirring. After completion of dropping, the mixture was heated to reflux for 6 hours. After completion of the reaction, the reaction vessel was cooled and concentrated under reduced pressure. Toluene was added to the residue, and the residue was purified by silica gel column chromatography. Further, the recovered product was recrystallized from toluene / hexane to obtain 0.243 g (yield 22.4%) of the compound represented by the above formula (5). In mass spectrometry (FD-MS), the peak was identified as M / z = 670, and the product was identified as the target product. In the elemental analysis, the calculated values were 68.05% carbon, 4.51% hydrogen, and 8.35% nitrogen, and the measured values were 68.29% carbon, 4.72% hydrogen, and 8.33% nitrogen.

Synthesis Example 3 Naphthalenecarboxylic Acid Derivative of Formula (6) First Step In a 200 ml four-necked flask, 5.0 g (18.6 mmol) of 1,4,5,8-naphthalenetetracarboxylic dianhydride and 50 ml of DMF are added and heated. Refluxed. To this, a mixture of 1.10 g (18.6 mmol) of 2-aminopropane and 25 ml of DMF was added dropwise with stirring. After completion of dropping, the mixture was heated to reflux for 6 hours. After completion of the reaction, the reaction vessel was cooled and concentrated under reduced pressure. Toluene was added to the residue, and the residue was purified by silica gel column chromatography. Further, the recovered product was recrystallized from toluene / hexane to obtain 2.08 g of monoimide B (yield 36.1%).

Second Step A 100 ml four-necked flask was charged with 2.0 g (6.47 mmol) of monoimide B, 0.162 g (3.23 mmol) of hydrazine monohydrate, 10 mg of p-toluenesulfonic acid, and 50 ml of toluene and heated to reflux for 5 hours. . After completion of the reaction, the container was cooled and concentrated under reduced pressure. The residue was purified by silica gel column chromatography. Further, the recovered product was recrystallized from toluene / ethyl acetate to obtain 0.810 g (yield 37.4%) of a naphthalenecarboxylic acid derivative represented by the formula (6). In mass spectrometry (FD-MS), the peak of M / z = 614 was observed and identified as the target product. In the elemental analysis, the calculated values were 66.45% carbon, 3.61% hydrogen, and 9.12% nitrogen, and the measured values were 66.28% carbon, 3.45% hydrogen, and 9.33% nitrogen.

Synthesis Example 4 Naphthalenecarboxylic Acid Derivative of Formula (7) First Step In a 200 ml four-necked flask, the above-mentioned dimer C 5.0 g (9.39 mmol) and DMF 50 ml were placed and heated to reflux. To this, a mixture of 1.08 g (9.39 mmol) DMF 25 ml 2-aminoheptane was added dropwise with stirring. After completion of dropping, the mixture was heated to reflux for 6 hours. After completion of the reaction, the reaction vessel was cooled and concentrated under reduced pressure. Toluene was added to the residue and purified by silica gel column chromatography to obtain 1.66 g of monoimide D (yield 28.1%).

Second Step A 100 ml four-necked flask was charged with 1.5 g (2.38 mmol) of monoimide D and 50 ml of DMF and heated to reflux. To this, a mixture of 2-aminooctane 0.308 g (2.38 mmol) and DMF 10 ml was added dropwise with stirring. After completion of dropping, the mixture was heated to reflux for 6 hours. After completion of the reaction, the reaction vessel was cooled and concentrated under reduced pressure. Toluene was added to the residue, and the residue was purified by silica gel column chromatography. Further, the recovered product was recrystallized from toluene / hexane to obtain 0.328 g (yield 18.6%) of a naphthalenecarboxylic acid derivative represented by the formula (7). In mass spectrometry (FD-MS), the peak of M / z = 740 was observed and identified as the target product. In the elemental analysis, the calculated values were 69.72% carbon, 5.44% hydrogen, and 7.56% nitrogen, and the measured values were 69.55% carbon, 5.26% hydrogen, and 7.33% nitrogen.

Synthesis Example 5 Naphthalenecarboxylic Acid Derivative of Formula (8) First Step In a 200 ml four-necked flask, the above-mentioned dimer C 5.0 g (9.39 mmol) and DMF 50 ml were placed and heated to reflux. To this, a mixture of 1.08 g (9.39 mmol) DMF 25 ml 2-aminoheptane was added dropwise with stirring. After completion of dropping, the mixture was heated to reflux for 6 hours. After completion of the reaction, the reaction vessel was cooled and concentrated under reduced pressure. Toluene was added to the residue and purified by silica gel column chromatography to obtain 1.66 g of monoimide D (yield 28.1%).

Second Step A 100 ml four-necked flask was charged with 1.5 g (2.38 mmol) of monoimide D and 50 ml of DMF and heated to reflux. To this, a mixture of 6-aminoundecane 0.408 g (2.38 mmol) and DMF 10 ml was added dropwise with stirring. After completion of dropping, the mixture was heated to reflux for 6 hours. After completion of the reaction, the reaction vessel was cooled and concentrated under reduced pressure. Toluene was added to the residue, and the residue was purified by silica gel column chromatography. Further, the recovered product was recrystallized with toluene / hexane to obtain 0.276 g (yield 14.8%) of the electron transport material represented by the above formula (8). In mass spectrometry (FD-MS), the peak of M / z = 782 was observed and identified as the target product. In the elemental analysis, the measured values were 70.77% carbon, 6.11% hydrogen, and 7.02% nitrogen while the calculated values were 70.57% carbon, 5.92% hydrogen, and 7.16% nitrogen.

Synthesis Example 6 Naphthalenecarboxylic acid derivative represented by formula (1-2A) First step In a 200 ml four-necked flask, 1,4,5,8-naphthalenetetracarboxylic dianhydride 5.0 g (18.6 mmol), 50 ml of DMF was added and heated to reflux. To this, a mixture of 1.62 g (18.6 mmol) of 2-aminopentane and 25 ml of DMF was added dropwise with stirring. After completion of dropping, the mixture was heated to reflux for 6 hours. After completion of the reaction, the container was cooled and concentrated under reduced pressure. Toluene was added to the residue, and the residue was purified by silica gel column chromatography. Further, the recovered product was recrystallized from toluene / hexane to obtain 3.49 g of monoimide E (yield 45.8%).

Second Step In a 100 ml four-necked flask, 3.0 g (7.33 mmol) of monoimide E, 0.983 g (3.66 mmol) of 1,4,5,8-naphthalenetetracarboxylic dianhydride, 0.368 g of hydrazine monohydrate ( 7.33 mmol), 10 mg of p-toluenesulfonic acid, and 50 ml of toluene were added and heated to reflux for 5 hours. After completion of the reaction, the container was cooled and concentrated under reduced pressure. The residue was purified twice by silica gel column chromatography. Further, the recovered product was recrystallized from toluene / ethyl acetate to obtain 0.939 g (yield 13.7%) of a compound represented by the formula (1-2A).

  In mass spectrometry (FD-MS), the peak of M / z = 934 was observed and identified as the target product. In the elemental analysis, the calculated values were 66.81% carbon, 3.67% hydrogen, and 8.99% nitrogen, and the measured values were 66.92% carbon, 3.74% hydrogen, and 9.05% nitrogen.

Example 1
A mixture having the following composition was placed in a ball mill pot and ball milled for 120 hours using φ10 mm alumina balls.
Titanium oxide (CR-60: Ishihara Sangyo) 500g
150 g of alkyd resin (Beckolite M6401-50 manufactured by Dainippon Ink and Chemicals, solid content: 50 wt%)
Melamine resin (Super Becamine L-121-60, Dainippon Ink and Chemicals, solid content 60wt%) 83g
Methyl ethyl ketone (Kanto Chemical) 317g
This coating solution was dip-coated on an aluminum drum having a diameter of 30 mm and a length of 340 mm, and dried at 135 ° C. for 20 minutes to form an undercoat layer having a thickness of 4.5 μm.

continue,
Non-metallic phthalocyanine pigment (Dainippon Ink and Chemicals Co., Ltd .: Fastogen Blue8120B) 140g
Polyvinyl butyral (Sekisui Chemical: BX-1) 90g
Cyclohexanone 2700g
These were dispersed for 40 minutes with a bead mill disperser (using φ0.5 mm PSZ balls as media) to prepare a charge generation layer coating solution. This coating solution was dip-coated on the undercoat layer and dried at 130 ° C. for 20 minutes to form a charge generation layer having a thickness of 0.15 μm.

Next, a charge transport layer coating solution having the following composition was prepared, and this coating solution was dip coated on the charge generation layer and dried at 120 ° C. for 20 minutes to form a charge transport layer having a thickness of 22 μm.
90g of naphthalenecarboxylic acid derivative (made by Ricoh) represented by the formula (7) as a charge transport material
Polycarbonate resin (Z-polyca, viscosity average molecular weight: 40,000, manufactured by Teijin Chemicals Ltd.) 100g
Silicone oil (KF-50, manufactured by Shin-Etsu Chemical) 0.02g
Tetrahydrofuran (Kanto Chemical) 1200g
further,
White conductive titanium oxide (ET-500W; made by Ishihara Sangyo) 18.2g
Naphthalenecarboxylic acid derivative represented by formula (7) as a charge transport material (Ricoh) 3g
Polyvinyl butyral resin (XYHL; made by UCC) 7.8g
Cyclohexanone (Kanto Chemical) 122.2g
A ball mill pot was used to carry out ball milling for 48 hours using a φ10 mm SUS ball, and then the milling solution was taken out. 10.2 g of a 10% cyclohexanone solution of toluene-2,4-diisocyanate, 171.1 g of cyclohexanone (manufactured by Kanto Chemical), methyl 114.1 g of ethyl ketone (manufactured by Kanto Chemical Co., Inc.) was added and mixed and stirred to prepare a surface protective layer coating solution. This coating solution was spray-coated on the charge transport layer and dried at 130 ° C. for 15 minutes to form a surface protective layer having a thickness of 2 μm to produce an electrophotographic photoreceptor.

(Example 2)
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that titanyl phthalocyanine prepared in accordance with the following pigment synthesis example 1 was used in place of the X-type metal-free phthalocyanine (Fastogen Blue 8120B) in Example 1. .

(Pigment synthesis example 1)
A pigment was prepared according to Japanese Patent Application Laid-Open No. 2001-19871. That is, 29.2 g of 1,3-diiminoisoindoline and 200 ml of sulfolane are mixed, and 20.4 g of titanium tetrabutoxide is added dropwise under a nitrogen stream. After completion of the dropping, the temperature was gradually raised to 180 ° C., and the reaction was carried out by stirring for 5 hours while keeping the reaction temperature between 170 ° C. and 180 ° C. After completion of the reaction, the mixture was allowed to cool, and then the precipitate was filtered, washed with chloroform until the powder turned blue, then washed several times with methanol, further washed several times with hot water at 80 ° C., and dried. Crude titanyl phthalocyanine was obtained. Dissolve the crude titanyl phthalocyanine in 20 times the amount of concentrated sulfuric acid, add dropwise to 100 times the amount of ice water with stirring, filter the precipitated crystals, and then repeat washing with water until the washing solution becomes neutral (ion-exchanged water after washing). PH value was 6.8), and a titanyl phthalocyanine pigment wet cake (water paste) was obtained. 40 g of the obtained wet cake (water paste) was put into 200 g of tetrahydrofuran, stirred for 4 hours, filtered and dried to obtain titanyl phthalocyanine powder. This is designated as Pigment 1.

  The solid content concentration of the wet cake was 15 wt%. The weight ratio of the crystal conversion solvent to the wet cake is 33 times. In addition, the halide is not used for the raw material of the synthesis example 1.

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

(X-ray diffraction spectrum measurement conditions)
X-ray tube: Cu
Voltage: 50kV
Current: 30mA
Scanning speed: 2 ° / min Scanning range: 3 ° to 40 °
Time constant: 2 seconds The average particle size in the charge generation layer coating solution using titanyl phthalocyanine was measured by CAPA-700 manufactured by Horiba, Ltd. and found to be 0.31 μm.

(Example 3)
Example 2 except that the naphthalenecarboxylic acid derivative of the formula (7) used as the charge transport material for the charge transport layer and the surface protective layer in Example 2 was changed to a naphthalenecarboxylic acid derivative of the formula (4) (manufactured by Ricoh). An electrophotographic photosensitive member was produced in exactly the same manner.
(Example 4)
A surface protective layer coating solution was prepared in exactly the same manner as in Example 2 except that the titanium oxide used for adjusting the surface protective layer in Example 2 was changed to tin oxide (SN-100; manufactured by Ishihara Sangyo). This coating solution was spray-coated on the charge transport layer and dried at 130 ° C. for 15 minutes to form a surface protective layer having a thickness of 3.0 μm to produce an electrophotographic photosensitive member.

(Example 5)
An electrophotographic photosensitive member was produced in the same manner as in Example 2 except that the naphthalenecarboxylic acid derivative of formula (7) used as the charge transport material in the surface protective layer in Example 2 was omitted.

(Example 6)
Example 2 except that the naphthalenecarboxylic acid derivative of the formula (7) used as the charge transport material for the charge transport layer and the surface protective layer in Example 2 was changed to a naphthalenecarboxylic acid derivative represented by the formula (1-2A). An electrophotographic photosensitive member was produced in the same manner as described above.

(Example 7)
In Example 2, the naphthalenecarboxylic acid derivative of the formula (7) used as the charge transporting material in the charge transporting layer was changed from 90 g to 71.8 g, and 18.2 g of the naphthalenecarboxylic acid derivative represented by the formula (1-3A) was added. Furthermore, the naphthalenecarboxylic acid derivative of the formula (7) used as the charge transport material for the surface protective layer was changed from 3 g to 2.4 g, and 0.6 g of the naphthalenecarboxylic acid derivative represented by the formula (1-3A) was added. An electrophotographic photosensitive member was produced in exactly the same manner as in Example 2.

(Comparative Example 1)
Electrophotography in exactly the same manner as in Example 2, except that the charge transport material formula (7) used in the charge transport layer and the surface protective layer in Example 2 was changed to the charge transport material of the following formula (10) (manufactured by Ricoh). A photoconductor was prepared.

このようにして作成した実施例1の電子写真感光体をソフトローラー帯電の反転現像方式デジタル複写機イマジオＭＦ２５０（リコー製；高圧電源をプラス帯電用に改造）に取り付け約２万枚のコピー（画像密度５％）を行い、画像濃度、画像ボケ、地肌汚れ等の画像品質、及び感光体表面の傷、フィルミング等を目視で評価した。高圧電源は表面電位が＋５００Ｖとなるように印加電圧を設定し、試験終了に至るまでこの帯電条件で試験を実施した。また、現像バイアスは＋３５０Ｖに設定し、トナーは極性制御材を変更して正帯電トナーとした。

The electrophotographic photosensitive member of Example 1 prepared in this way is attached to a reverse development type digital copying machine Imagio MF250 (made by Ricoh; high voltage power supply modified for positive charging) with soft roller charging, and about 20,000 copies (images) The density was 5%), and image quality such as image density, image blur, and background stains, and scratches and filming on the surface of the photoreceptor were visually evaluated. The applied voltage was set so that the surface potential of the high-voltage power supply was +500 V, and the test was conducted under this charging condition until the end of the test. The developing bias was set to +350 V, and the toner was changed to a positive polarity toner by changing the polarity control material.

  In the electrophotographic photosensitive members of Examples 2 to 7 and Comparative Example 1, approximately 20,000 copies (in the same manner as in Example 1) except that the charging roller is changed to the magnetic brush charging member shown in FIG. The image density was 5%) and the charging property to the photoreceptor was evaluated.

  These results are shown in Table 1.

以上、本発明の実施例を具体的に説明してきたが、本発明は、これらの実施例に限定されるものではなく、これら本発明の実施例を、本発明の主旨及び範囲を逸脱することなく、変更又は変形することができる。

Although the embodiments of the present invention have been specifically described above, the present invention is not limited to these embodiments, and these embodiments of the present invention depart from the spirit and scope of the present invention. And can be changed or modified.

1 is a schematic cross-sectional view of an electrophotographic apparatus of the present invention. 2 (I) is a magnetic brush charging method, FIG. 2 (II) is a (conductive) brush charging method, FIG. 2 (III) is a roller charging method using a conductive soft roller, and FIG. 2 (IV) is fixed. FIG. 2 (V) is a diagram showing a belt-type charging method using two rollers and a conductive belt. 1 is a schematic cross-sectional view of an electrophotographic photoreceptor of the present invention having a configuration in which a photosensitive layer and a surface protective layer are provided on a conductive substrate. FIG. 2 is a schematic cross-sectional view of the electrophotographic photoreceptor of the present invention of the function separation type in which the photosensitive layer is composed of a charge generation layer (CGL) and a charge transport layer (CTL). FIG. 2 is a schematic cross-sectional view of the electrophotographic photoreceptor of the present invention in which an undercoat layer is inserted between the conductive substrate and the CGL and CTL of the function-separated type photosensitive layer. It is a figure which shows the X-ray-diffraction spectrum of the titanyl phthalocyanine of the pigment synthesis example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Electrophotographic photoreceptor 12 Charging device 13 Image exposure 14 Developing roller 15 Paper feed roller 16 Transfer roller 17 Cleaning blade 18 Static elimination lamp 19 Fixing unit

Claims (14)

An electrophotographic photosensitive member having a structure in which at least a photosensitive layer and a surface protective layer are sequentially laminated on a conductive support; and a charging member disposed in contact with the electrophotographic photosensitive member. A voltage is applied to the charging member. In the image forming apparatus for injecting and charging the electrophotographic photosensitive member by applying, the surface protective layer of the electrophotographic photosensitive member contains a conductive metal oxide, and the photosensitive layer or the surface protective layer is represented by the formula (1). An image forming apparatus comprising a naphthalenecarboxylic acid derivative.

Wherein R 1 and R 2 each independently represent a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aralkyl group, and R 3 , R4, R5, R6, R7, R8, R9, R10 are each independently a hydrogen atom, a halogen atom, a cyano group, a nitro group, an amino group, a hydroxyl group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group. Represents a group selected from the group consisting of a group, a substituted or unsubstituted aralkyl group.) An electrophotographic photosensitive member having a structure in which at least a photosensitive layer and a surface protective layer are sequentially laminated on a conductive support; and a charging member disposed in contact with the electrophotographic photosensitive member. A voltage is applied to the charging member. In the image forming apparatus for injecting and charging the electrophotographic photosensitive member by applying, the surface protective layer of the electrophotographic photosensitive member contains a conductive metal oxide, and the photosensitive layer or the surface protective layer has the formula (1- An image forming apparatus comprising the naphthalenecarboxylic acid derivative of 2).

Wherein R 1 and R 2 each independently represent a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aralkyl group, and R 3 , R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14 are each independently a hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, substituted or unsubstituted alkyl group Represents a group selected from the group consisting of a substituted or unsubstituted cycloalkyl group and a substituted or unsubstituted aralkyl group, and n is a repeating unit and represents an integer of 1 to 100.) The image forming apparatus according to claim 1, further comprising a naphthalenecarboxylic acid derivative represented by the following formula (1-3) in addition to the naphthalenecarboxylic acid derivative.

Wherein R15 and R16 each independently represents a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, and a substituted or unsubstituted aralkyl group; , R18, R19 and R20 are each independently a hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted aralkyl. Represents a group selected from the group consisting of groups.)   The image forming apparatus according to claim 1, wherein the electrophotographic photosensitive member is injected and charged only with a positive DC voltage.   The image forming apparatus according to claim 1, wherein the conductive metal oxide is a titanium oxide-based metal oxide.   The image forming apparatus according to claim 1, wherein the charging member is a magnetic brush charger including a magnetic brush made of magnetic particles.   7. The image forming apparatus according to claim 1, wherein the photosensitive layer is a multilayer electrophotographic photosensitive member including a charge generation layer and a charge transport layer. The image forming apparatus according to claim 1, wherein the surface protective layer has a volume resistance of 10 ^{9 to} 10 ¹² Ω · cm.   9. The image forming apparatus according to claim 1, wherein the charge generating material contained in the photosensitive layer is titanyl phthalocyanine.   The charge generating material contained in the photosensitive layer is titanyl phthalocyanine having a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray of CuKα. The image forming apparatus according to any one of claims 1 to 8.   The titanyl phthalocyanine has a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray of CuKα, and further 9.4 °, 9.6 °, 24 It has a major peak at 0.0 °, the lowest diffraction peak at 7.3 °, and a peak between the 7.3 ° peak and the 9.4 ° peak. The image forming apparatus according to claim 9, further comprising a titanyl phthalocyanine crystal having no peak at 26.3 °.   The image forming apparatus according to claim 9, wherein an average particle size of the titanyl phthalocyanine is 0.60 μm or less.   13. The image forming method for use in an image forming apparatus according to claim 1, wherein an electrostatic latent image is formed on an electrophotographic photosensitive member by at least charging and image exposure, wherein the developing means is reverse development. An image forming method characterized by being a system.   13. A process cartridge for an image forming apparatus, which is detachable from an apparatus main body and includes at least an electrophotographic photosensitive member, a charging unit, a developing unit, and a cleaning unit. An image forming apparatus process cartridge for use in the image forming apparatus according to claim 1.

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