JP4836690B2 - Electrophotographic photosensitive member, image forming apparatus, and process cartridge - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member, an image forming apparatus, and a process cartridge used for copying, printers, facsimiles and the like.

  In recent years, there has been a remarkable development of information processing system machines using electrophotography. In particular, an optical printer that converts information into a digital signal and records information by light has a remarkable improvement in print quality and reliability. This digital recording technology is applied not only to printers but also to ordinary copying machines, and so-called digital copying machines have been developed. In addition, since a variety of information processing functions are added to a conventional copying machine equipped with this digital recording technology for analog copying, it is expected that its demand will increase further in the future. In addition, with the spread of personal computers and the improvement in performance, the progress of digital color printers for performing color output of images and documents is rapidly progressing.

  Electrophotographic photoreceptors used in image forming apparatuses are roughly classified into organic photoreceptors and inorganic photoreceptors, but organic photoreceptors are easier to manufacture than conventional inorganic photoreceptors, are inexpensive, and charge transport. In recent years, it has been widely used because it has the advantage that there are various options for photoconductor materials such as materials, charge generation materials, and binder resins, and the degree of freedom in functional design is high.

  The organic photoreceptor includes a single layer type photoreceptor in which a charge transport material (a hole transport agent, an electron transport material) is dispersed together with a charge generation material in the same photosensitive layer, a charge generation layer containing the charge generation material, There is a laminate type photoreceptor in which a charge transport layer containing a transport material is laminated.

  Most of the laminated photoreceptors are negatively charged, and the positively charged laminated photoreceptor has not been put into practical use. The reason is that an electron transport material having excellent electron transport ability, low toxicity, and high compatibility with the binder resin has not been put into practical use. On the other hand, single-layer type photoreceptors generally have positive and negative sensitivities, but most of them are used with positive charge because of the low electron transport ability of electron transport materials.

  In general, an image forming apparatus using an electrophotographic method charges a photoreceptor (main charging process), forms an electrostatic latent image by exposing an image (exposure process), and develops the electrostatic latent image with toner ( (Development step), the formed toner image is transferred to a transfer medium (transfer step), and fixed to form an image. The residual toner on the photoconductor is cleaned by a cleaning blade or the like (cleaning process), and the residual charge on the photoconductor is erased by a static elimination lamp or the like (static elimination process). A reversal development method in which development is performed using toner having the same polarity as the charging polarity applied to the photosensitive member in the charging step is widely used in digital image forming apparatuses.

  When the electrophotographic photosensitive member is used in a reversal development type digital image forming apparatus, the polarity of the transfer voltage applied to the photosensitive member in the transfer step is opposite to the charging polarity of the photosensitive member. Normally, it is not applied directly to the photoconductor in the transfer process but via the transfer medium (paper), and is not applied when the transfer medium does not pass through the transfer process. However, it is difficult to control the ON / OFF timing of the transfer voltage. In many cases, the front and rear end portions of the medium are directly applied to the photosensitive member. That is, the transfer voltage starts to be applied before the leading edge of the transfer medium reaches the position of the transfer means, and the transfer voltage is still applied even if a part of the transfer means is exposed by the passage of the rear end of the transfer medium. In order to continue, a transfer voltage is directly applied to the photoconductor in the portion.

  For this reason, for example, in the case of a positively charged single layer type photoreceptor, since the polarity of the voltage applied by the transfer device is negative, negative space charges remain on the photoreceptor portion to which a negative voltage is applied. As described above, since the single-layer type photoreceptor has sensitivity in both polarities, the negative space charge is erased in the next static elimination step.

  However, when the sensitivity of the positively charged single layer type photoreceptor to the negative polarity is poor (electron transporting material has poor electron transport ability), the negative space charge is not sufficiently erased and is positively charged in the next charging step. However, the potential drop is caused by the effect of space charge.

  As a result of the lowering of the charged potential, a potential drop in the post-exposure potential occurs in the exposure process, and an image defect (transfer memory image) occurs in which the image density of the portion becomes higher after toner development.

The single-layer type photoreceptor is normally positively charged in the next charging process after the charge on the surface of the photoreceptor is erased uniformly in the charge removal process through the exposure process and the development process.
However, when the sensitivity of the positive polarity of the positively charged single layer type photoreceptor is poor, the space charge density opposite to the charged polarity is larger in the image exposed portion than in the non-exposed portion, and the next charging step. The charged potential is lowered, and an image exposure memory image is easily generated. When used in an image forming apparatus that does not have a charge eliminating step, the surface of the photoconductor is not uniformly exposed, so that the density difference between the exposed portion and the non-exposed portion in the image exposure memory image tends to become more prominent.

  With respect to such a problem, Patent Document 1, Patent Document 2, Patent Document 3, and Patent Document 4 disclose a technique for specifying a constituent material type of a single-layer type photoreceptor and a range of difference in positive and negative photosensitivity. Although examples are recognized, none of them have sufficient electron transport ability of the electron transport material, and are insufficient to prevent image defects due to transfer and image exposure.

  Also disclosed are examples (Patent Document 5, Patent Document 6, Patent Document 7, Patent Document 8, and Patent Document 9) of preventing and reducing image defects with a specific configuration and conditions for the transfer memory image. However, it requires a transfer mechanism with a complicated mechanism, making it difficult to reduce the size and cost, or sacrificing the transfer efficiency of the toner, and easily causing toner transfer dust. In other words, it is insufficient as a fundamental technique for preventing transfer memory.

As described above, the present situation is that satisfactory results have not been obtained with respect to techniques for preventing and reducing image defects due to transfer and exposure of an electrophotographic photosensitive member having both positive and negative photosensitivity.
Japanese Patent No. 3532808 JP 2001-255678 A Japanese Patent No. 3638500 Japanese Patent Laid-Open No. 2001-312075 Japanese Patent Laid-Open No. 11-24446 JP 2000-242089 A JP 2001-215818 A JP 2002-49194 A Japanese Patent No. 3538389

  The present invention has been made in view of the present situation, and it is an object to solve the image defects due to transfer and exposure of a conventional electrophotographic photosensitive member having both positive and negative photosensitivity, and to achieve the following object. To do. The present invention prevents the generation of a memory image due to transfer and exposure in an image forming apparatus using an electrophotographic photosensitive member having both positive and negative photosensitivity, and can produce a high-quality image even in repeated image formation over a long period of time. An object of the present invention is to provide an electrophotographic photosensitive member, an image forming apparatus, and a process cartridge capable of outputting.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have developed an unprecedented novel image forming apparatus using an electrophotographic photosensitive member having both positive and negative photosensitivities, which has an excellent electron transport ability in the photosensitive layer. By using a photoconductor containing an electron transport material and having a photosensitivity ratio between positive and negative polarities of the photoconductor within a certain range, high-quality images can be output over a long period of time without generating transfer or image exposure memory. It has been found that an image forming apparatus can be provided.

Specifically, the electrophotographic photosensitive member contains an electron transport material represented by the following general formula 1 or general formula 1-A, the electrophotographic photosensitive member has positive and negative photosensitivity, and light in each polarity. By using a photoconductor having a ratio E1 / 2 (negative) / E1 / 2 (positive) of sensitivity E1 / 2 (positive) and E1 / 2 (negative) of 0.5 to 3, transfer and image exposure memory images Can be prevented.
(Here, E1 / 2 is required for the surface potential to be reduced to 1/2 by exposing the electrophotographic photosensitive member to ± 800 V at room temperature (23 ° C., 55% RH) and then exposing it to monochromatic light having a wavelength of 780 nm. Exposure energy per 1 cm ^{2 of} photosensitive layer surface (μJ / cm ² ))
<General formula 1>

｛但し、上記一般式中、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。｝
〈一般式１―Ａ〉

{However, in the above general formula, R1 and R2 are each independently 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. R 3, R 4, R 5, R 6, R 7, R 8, R 9, R 10 are each independently a hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted A group selected from the group consisting of a substituted cycloalkyl group and a substituted or unsubstituted aralkyl group. }
<General Formula 1-A>

｛ただし、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。｝
本発明に用いられる一般式１又は一般式１―Ａで表される化合物は非常に優れた電子輸送性を示すため、感光層に電子輸送材料として含有させることで、従来の単層型感光体の欠点であった負帯電感度を飛躍的に向上させることが可能となる。従って、先述したように、転写及び像露光時に生じる逆極性の空間電荷を著しく低減することが可能となり、メモリー画像が防止できることになる。

{However, in the formula, 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, and a substituted or unsubstituted aralkyl group. , R3, 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 The group selected from the group which consists of an alkyl group, a substituted or unsubstituted cycloalkyl group, and a substituted or unsubstituted aralkyl group is represented, n is a repeating unit and represents the integer of 1-100. }
Since the compound represented by the general formula 1 or general formula 1-A used in the present invention exhibits very excellent electron transport properties, a conventional single layer type photoreceptor can be obtained by containing it in the photosensitive layer as an electron transport material. Thus, it is possible to dramatically improve the negative charging sensitivity which has been a drawback of the above. Therefore, as described above, it is possible to remarkably reduce the reverse polarity space charge generated at the time of transfer and image exposure, thereby preventing a memory image.

  On the other hand, even when using an electron transport material excellent in electron transport ability represented by General Formula 1 or General Formula 1-A, the positive charge and negative charge sensitivities change depending on the material composition ratio of the photosensitive layer. It is necessary to select the material composition ratio so that the ratio of photosensitivity (E1 / 2) is in the range of 0.5 to 3 (0.5 or more and 3 or less). In this way, an image forming apparatus can be provided in which the amount of charge reduction due to negative space charges caused by transfer and image exposure can be made extremely small, and as a result, a high-quality image can be obtained over a long period without the occurrence of a memory image. It becomes possible.

  In addition, since the photoconductor of the present invention contains an electron transport material having greatly improved electron transport ability, good results can be obtained with or without a charge removal step after transfer.

  Furthermore, the sensitivity is improved by using a specific material for the charge generation material. In the present invention, a known material can be used as the charge generating material, but among them, a material having a phthalocyanine structure is preferable in combination with the charge transporting material used in the present invention.

  Among them, in particular, by using titanyl phthalocyanine as shown in the following structural formula (1) having titanium as a central metal, a particularly sensitive photoconductor can be obtained, and the speed of the image forming apparatus can be further increased. Is possible.

  Structural formula (1)

チタニルフタロシアニンの合成法や電子写真特性に関する文献としては、例えば特開昭５７―１４８７４５号公報、特開昭５９―３６２５４号公報、特開昭５９―４４０５４号公報、特開昭５９―３１９６５号公報、特開昭６１―２３９２４８号公報、特開昭６２―６７０９４号公報などが挙げられる。また、チタニルフタロシアニンには種々の結晶系が知られており、特開昭５９―４９５４４号公報、特開昭５９―１６６９５９号公報、特開昭６１―２３９２４８号公報、特開昭６２―６７０９４号公報、特開昭６３―３６６号公報、特開昭６３−１１６１５８号公報、特開昭６３―１９６０６７号公報、特開昭６４―１７０６６号公報、特開２００１―１９８７１号公報等に各々結晶形の異なるチタニルフタロシアニンが記載されている。

References relating to the synthesis method and electrophotographic characteristics of titanyl phthalocyanine include, for example, JP-A-57-148745, JP-A-59-36254, JP-A-59-44054, JP-A-59-31965. JP-A 61-239248, JP-A 62-67094, and the like. In addition, various crystal systems are known for titanyl phthalocyanine. JP-A 59-49544, JP-A 59-166959, JP-A 61-239248, JP-A 62-67094. The crystal forms are described in JP-A 63-366, JP-A 63-116158, JP-A 63-196067, JP-A 64-17066, JP-A 2001-19871, etc. Of different titanyl phthalocyanines are described.

  Of these 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 °, Further, 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 7.4 ° 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.

  Furthermore, since the photoconductor of the present invention has improved sensitivity characteristics in the negative polarity as compared with a conventional positively charged photoconductor, it can be used in a negative charging process. Single layer type photoreceptors are less expensive than multilayer type photoreceptors because of their layer structure and ease of manufacture, so a reversal development system using multilayer type photoreceptors in a negative charging process that has been widely used in the past. By combining the single layer type photoreceptor of the present invention with the image forming apparatus, the cost of the image forming apparatus can be reduced.

  That is, this invention consists of the following aspects.

  (1) An electrophotographic photoreceptor having at least a photosensitive layer on a conductive support, wherein the photosensitive layer contains a charge generation material and an electron transport material represented by the following general formula 1-Z, and the electrophotographic photoreceptor Has positive and negative photosensitivity, and the ratio E1 / 2 (negative) / E1 / 2 (positive) of the photosensitivities E1 / 2 (positive) and E1 / 2 (negative) in each polarity is 0.5. An electrophotographic photosensitive member, characterized in that it is ~ 3.

  <General formula 1-Z>

｛ただし、上記一般式中、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、２から１０２までの整数を表す。｝
（２）少なくとも導電性支持体上に感光層を有する電子写真感光体において、該感光層中に電荷発生材料と下記一般式１で表される電子輸送材料を含み、該電子写真感光体が正負両極性の光感度を有し、それぞれの極性での光感度Ｅ１／２（正）、Ｅ１／２（負）の比Ｅ１／２（負）／Ｅ１／２（正）が０．５〜３であることを特徴とする電子写真感光体。

{However, in the above general formula, R 1 and R 2 are each independently 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. R3, R4, R5 and R6 each independently represent 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, substituted or Represents a group selected from the group consisting of unsubstituted aralkyl groups, n is a repeating unit, and represents an integer of 2 to 102; }
(2) In an electrophotographic photoreceptor having at least a photosensitive layer on a conductive support, the photosensitive layer contains a charge generation material and an electron transport material represented by the following general formula 1, and the electrophotographic photoreceptor is positive or negative. Bipolar photosensitivity, ratio of photosensitivity E1 / 2 (positive) and E1 / 2 (negative) at each polarity, E1 / 2 (negative) / E1 / 2 (positive) is 0.5-3 An electrophotographic photoreceptor, characterized in that

(Where E1 / 2 is the exposure energy (μJ / μm) per 1 cm ^{2 of the} photoreceptor surface required to charge the electrophotographic photoreceptor to ± 800 V and then expose it to monochromatic light with a wavelength of 780 nm to reduce the surface potential to 1/2. cm ² ))
<General formula 1>

｛但し、上記一般式中、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。｝
（３）少なくとも導電性支持体上に感光層を有する電子写真感光体において、該感光層中に電荷発生材料と下記一般式１―Ａで表される電子輸送材料を含み、該電子写真感光体が正負両極性の光感度を有し、それぞれの極性での光感度Ｅ１／２（正）、Ｅ１／２（負）の比Ｅ１／２（負）／Ｅ１／２（正）が０．５〜３であることを特徴とする電子写真感光体。

{However, in the above general formula, R1 and R2 are each independently 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. R 3, R 4, R 5, R 6, R 7, R 8, R 9, R 10 are each independently a hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted A group selected from the group consisting of a substituted cycloalkyl group and a substituted or unsubstituted aralkyl group. }
(3) An electrophotographic photoreceptor having at least a photosensitive layer on a conductive support, wherein the photosensitive layer contains a charge generating material and an electron transport material represented by the following general formula 1-A, and the electrophotographic photoreceptor Has positive and negative photosensitivity, and the ratio E1 / 2 (negative) / E1 / 2 (positive) of the photosensitivities E1 / 2 (positive) and E1 / 2 (negative) in each polarity is 0.5. An electrophotographic photosensitive member, characterized in that it is ~ 3.

  <General Formula 1-A>

｛ただし、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。｝
（４）前記電荷発生材料がフタロシアニンであることを特徴とする前記第（１）項乃至第（３）項のいずれか１項に記載の電子写真感光体。

{However, in the formula, 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, and a substituted or unsubstituted aralkyl group. , R3, 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 The group selected from the group which consists of an alkyl group, a substituted or unsubstituted cycloalkyl group, and a substituted or unsubstituted aralkyl group is represented, n is a repeating unit and represents the integer of 1-100. }
(4) The electrophotographic photosensitive member according to any one of (1) to (3), wherein the charge generation material is phthalocyanine.

  (5) The electrophotographic photosensitive member as described in (4) above, wherein the phthalocyanine is titanyl phthalocyanine.

  (6) 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 Cu—Kα ray (wavelength 1.542 mm), and further 9.4 Major peaks at °, 9.6 °, 24.0 ° and the lowest diffraction peak at 7.3 °, 7.3 ° peak and 9.4 ° The electrophotographic photosensitive member according to item (5), wherein there is no peak between the peaks.

  (7) In addition to the electron transporting material, the electron transporting material further contains an electron transporting material represented by the following general formula 1-B. Any one of the items (1) to (6) The electrophotographic photoreceptor described in 1.

  <General formula 1-B>

｛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。｝
（８）少なくとも電子写真感光体と、該電子写真感光体を帯電する帯電手段と、帯電後に像露光を行って静電潜像を形成する像露光手段と、該静電潜像を現像する現像手段と、現像像を転写する手段とを有する画像形成装置において、該電子写真感光体が前記第（１）乃至（７）のいずれか１項に記載の電子写真感光体であることを特徴とする画像形成装置。

{Wherein R15 and R16 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 R17 , 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. }
(8) At least an electrophotographic photosensitive member, charging means for charging the electrophotographic photosensitive member, image exposure means for performing image exposure after charging to form an electrostatic latent image, and development for developing the electrostatic latent image And an electrophotographic photosensitive member according to any one of (1) to (7), wherein the electrophotographic photosensitive member is an electrophotographic photosensitive member according to any one of (1) to (7). Image forming apparatus.

  (9) The image forming apparatus according to item (8), wherein the charging process is performed by positive charging.

  (10) The image forming apparatus according to (8), wherein the charging process is performed with positive charging.

  (11) The image forming apparatus according to any one of (8) to (10), wherein the shape of the transfer unit is a roller or a belt.

  (12) The image forming apparatus includes a plurality of electrophotographic photosensitive members, and forms a color image by sequentially superimposing single-color toner images developed on the respective electrophotographic photosensitive members. The image forming apparatus according to any one of (8) to (11).

  (13) Intermediate transfer means for primary transfer of the toner image developed on the electrophotographic photosensitive member onto the intermediate transfer member by the image forming apparatus and then secondary transfer of the toner image on the intermediate transfer member onto the recording material An image forming apparatus comprising: a plurality of color toner images sequentially superimposed on an intermediate transfer member to form a color image; and the color image is secondary-transferred collectively onto a recording material. The image forming apparatus according to any one of (8) to (12).

  (14) An image forming apparatus process cartridge comprising at least an electrophotographic photosensitive member, wherein the image is used in the image forming apparatus described in any one of (8) to (13). Process cartridge for forming apparatus.

  According to the present invention, in an image forming apparatus using an electrophotographic photosensitive member having both positive and negative photosensitivities, image defects (memory images) due to transfer and exposure do not occur, and a high-quality image is output over a long period of time. It is possible to provide an image forming apparatus capable of performing the above.

  The electrophotographic apparatus used in the present invention will be described below with reference to the drawings. In any of the drawings, the photoconductor is an electrophotographic photoconductor that satisfies the requirements of the present invention.

  FIG. 1 is a schematic view for explaining an example of an image forming element of an electrophotographic apparatus according to the present invention, and modifications as described later also belong to the category of the present invention.

  In FIG. 1, a photoconductor 11 is an electrophotographic photoconductor that satisfies the requirements of the present invention.

  The photoconductor 11 has a drum shape, but may have a sheet shape or an endless belt shape.

  As the charging means 12, known means such as a corotron, a scorotron, a solid state charger (solid state charger), and a charging roller are used.

  As the transfer means 16, the above charger can be generally used, but a roller or sheet-like transfer means is effective.

  Reference numeral 13 denotes exposure means, and a semiconductor laser (LD), a light emitting diode (LED), or the like can be used. In some cases, various filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range. .

  1A is a static elimination means, and is used according to necessity. Examples of the light source include fluorescent materials, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light emitting diodes (LEDs), semiconductor lasers (LDs), electroluminescence (ELs) and the like.

  The toner 15 developed on the photoconductor by the developing means 14 is transferred to the image receiving medium 18, but not all is transferred, and some toner remains on the photoconductor. Such toner is removed from the photoreceptor by the cleaning means 17. As the cleaning means, a rubber cleaning blade, a brush such as a fur brush, a mag fur brush, or the like can be used.

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

  Since the present invention is characterized by comprising a plurality of image forming elements as shown in FIG. 1, a plurality of these image forming elements are used in a horizontal or oblique arrangement.

  FIG. 2 shows an example for explaining another example of the image forming element of the electrophotographic apparatus according to the present invention. In FIG. 2, a photoconductor 11 is an electrophotographic photoconductor that satisfies the requirements of the present invention, and has an endless belt shape.

  Driven by driving means 1C, charged by charging means 12, image exposure by exposure means 13, development (not shown), transfer by transfer means 16, exposure before cleaning by pre-cleaning exposure means 1B, cleaning by cleaning means 17, and charge removal The charge removal by means 1A is repeated. In FIG. 2, light irradiation for pre-cleaning exposure is performed from the support side of the photoreceptor (in this case, the support is translucent).

  Also in the exposure means 13 of FIG. 2, a semiconductor laser (LD), a light emitting diode (LED), etc. can be used as a light source. In some cases, various filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range. .

  Since the present invention is characterized by comprising a plurality of image forming elements as shown in FIG. 2, a plurality of these image forming elements may be used horizontally or diagonally.

  The image forming elements described above exemplify the embodiments of the present invention, and other embodiments are of course possible. For example, in FIG. 2, the pre-cleaning exposure is performed from the support side, but this may be performed from the photosensitive layer side, or image exposure and neutralization light irradiation may be performed from the support side. On the other hand, the light irradiation process is illustrated as image exposure, pre-cleaning exposure, and static elimination exposure. In addition, a pre-transfer exposure, a pre-exposure of image exposure, and other known light irradiation processes are provided to light the photosensitive member. Irradiation can also be performed.

  Further, the image forming means as described above may be fixedly incorporated in a copying machine, a facsimile, or a printer, but may be incorporated in these apparatuses in the form of a process cartridge. A process cartridge is a single device (part) that contains a photosensitive member and includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit. There are many shapes and the like of the process cartridge, but a general example is shown in FIG.

  These process cartridges are detachable and easy to maintain.

  Since the present invention is characterized by comprising a plurality of image forming elements in the form of process cartridges as shown in FIG. 3, a plurality of these image forming elements are used horizontally or obliquely.

  4 and 5 show an example of the entire full-color electrophotographic apparatus according to the present invention. This electrophotographic apparatus is a type that uses four colors of yellow (Y), magenta (M), cyan (C), and black (Bk) as toner, and an image forming unit is provided for each color. In addition, photoconductors (11Y, 11M, 11C, 11Bk) for each color are provided. The photoreceptor 11 used in this electrophotographic apparatus is an electrophotographic photoreceptor that satisfies the requirements of the present invention. Similarly, around each of the photoconductors 11Y, 11M, 11C, and 11Bk, a charging unit 12, an exposure unit 13, a developing unit 14, a cleaning unit 17, and the like are disposed.

  Note that the exposure means 13 (13Y, 13M, 13C, 13Bk, 13Y, 13M, 13C, 13Bk in FIG. 5 is the same as described above). As described above, the light source is a semiconductor laser (LD) as a light source in the present invention. A diode (LED) or the like can be used. In some cases, various filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range. .

  Further, a transfer transfer belt 1G as a transfer material carrier that is brought into contact with and separated from each transfer position of each of the photoconductors 11Y, 11M, 11C, and 11Bk arranged on a straight line is stretched by a driving unit 1C. A transfer unit 16 is disposed at a transfer position facing each of the photoreceptors 1Y, 1M, 1C, and 1Bk with the conveyance transfer belt 1G interposed therebetween.

  Also in the electrophotographic apparatus as shown in FIGS. 4 and 5, it is possible to use the detachable process cartridge as described above as an image forming element for each color.

  Next, the electrophotographic photosensitive member used in the present invention will be described in detail.

  The photosensitive layer of the electrophotographic photosensitive member in the present invention is a single-layer type photosensitive layer containing a charge generation material and a charge transport material in a single layer.

  FIG. 6 is a cross-sectional view schematically showing an example of an electrophotographic photosensitive member used in the electrophotographic apparatus of the present invention. At least a charge generating material and the above general formula 1 or general formula 1 are formed on a conductive support 21. A photosensitive layer 22 containing an electron transport material represented by -A is provided.

  Although not shown, an undercoat layer can be provided between the conductive support 21 and the photosensitive layer 22, and a surface protective layer can be provided on the photosensitive layer 22.

(Conductive support)
Examples of the conductive support 21 include those having a volume resistance of 10 ¹⁰ Ω · cm or less, such as metals such as aluminum, nickel, chromium, nichrome, copper, silver, gold, platinum, and iron, tin oxide, and indium oxide. Oxide such as film or cylindrical plastic or paper coated by vapor deposition or sputtering, or a plate made of aluminum, aluminum alloy, nickel, stainless steel, etc., and drawing ironing method or impact ironing method. It is possible to use a tube that has been subjected to surface treatment by cutting, superfinishing, polishing, or the like after being made into a bare tube by a method such as the Extruded Ironing method, the Extruded Drawing method, or the cutting method.

(Underlayer)
In the electrophotographic photoreceptor used in the present invention, an undercoat layer may be provided between the photosensitive layer and the conductive support. The undercoat layer is provided for the purpose of improving adhesiveness, preventing moire, improving coatability of the upper layer, reducing residual potential, and preventing charge injection from the conductive support. In general, the undercoat layer is mainly composed of a resin. However, considering that the photosensitive layer is applied on the resin using a solvent, the resin is a resin having high resistance to general organic solvents. Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. In addition, a fine powder such as a metal oxide such as titanium oxide, silica, alumina, zirconium oxide, tin oxide, or indium oxide, or a metal sulfide or metal nitride may be added to the undercoat layer. These undercoat layers can be formed using an appropriate solvent and coating method, as in the case of the photosensitive layer described above.

  Further, as the undercoat layer, a metal oxide layer formed by using, for example, a sol-gel method using a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like is also useful. In addition to this, alumina provided by anodic oxidation, organic substances such as polyparaxylylene (parylene), and inorganic substances such as silicon oxide, tin oxide, titanium oxide, ITO, and ceria were provided by a vacuum thin film manufacturing method. It can be used well as an undercoat layer. The thickness of the undercoat layer is suitably from 0.1 to 10 μm, more preferably from 1 to 5 μm.

(Single layer type photosensitive layer)
As a material that can be used for the charge transporting material even in the case of a single layer structure, it is essential to use the electron transporting material represented by the above general formula 1 or general formula 1-A. An electron transport material (acceptor) and a hole transport material (donor) can be used in combination.

  The blending ratio of each constituent material may be such that the photosensitivity ratio E1 / 2 (negative) / E1 / 2 (positive) is 0.5 to 3, as shown in claim 1. The mixing ratio of the materials is as follows.

  The charge generation material is suitably 0.01 to 50 parts by weight, preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the binder resin.

  The electron transport material is suitably 1 to 100 parts by weight, preferably 5 to 80 parts by weight with respect to 100 parts by weight of the binder resin.

  The hole transport material is suitably 5 to 200 parts by weight, preferably 20 to 150 parts by weight, based on 100 parts by weight of the binder resin.

  The ratio of the electron transporting material to the hole transporting material is 1: 9 to 9: 1, preferably 2: 8 to 8: 2.

  In order to satisfy the high sensitivity of the photoreceptor, it is preferable that the amount of the charge transport material (electron transport material + hole transport material) is 70 parts by weight or more with respect to 100 parts by weight of the binder resin component. .

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

  Further, if necessary, low-molecular compounds such as antioxidants, plasticizers, lubricants and ultraviolet absorbers and leveling agents can be added to the photosensitive 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 such as a binder resin. The amount of the leveling agent used is the polymer compound. About 0.001 to 5 parts by weight is appropriate for 100 parts by weight. As such leveling agents, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain, and the like can be 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.

  The film thickness of the photosensitive layer is suitably about 10 to 45 μm, preferably about 15 to 36 μm, and when resolution is required, 25 μm or less is appropriate.

(Charge generation material for single-layer photosensitive layer)
As the charge generating material that can be used for the photosensitive layer having a single layer structure, a known material can be used. For example, phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine, azulenium salt pigments, squaric acid methine pigments, azo pigments having a carbazole skeleton, azo pigments having a triphenylamine skeleton, azo pigments having a diphenylamine skeleton, dibenzo An azo pigment having a thiophene skeleton, an azo pigment having a fluorenone skeleton, an azo pigment having an oxadiazol skeleton, an azo pigment having a bisstilbene skeleton, an azo pigment having a distyryl oxadiazol skeleton, and a distyrylcarbazole skeleton Azo pigments, perylene pigments, anthraquinone or polycyclic quinone pigments, quinoneimine pigments, diphenylmethane and triphenylmethane pigments, benzoquinone and naphthoquinone pigments, cyanine and azomethine pigments, Jigoido pigments, bisbenzimidazo - such as Le based pigments. These charge generation materials can be used singly or as a mixture of two or more. As described above, phthalocyanine pigments are particularly preferable from the viewpoint of various properties required for the present invention.

  By using titanyl phthalocyanine having titanium as a central metal among phthalocyanine-based pigments, a photosensitive layer having particularly high sensitivity can be obtained, and the speed of the electrophotographic apparatus can be further increased. 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 °, Further, 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 7.4 ° 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.

  These pigments are preferably dispersed in advance by a ball mill, attritor, sand mill or the like using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, or butanone. Moreover, you may disperse | distribute with binder resin as needed at the time of dispersion | distribution.

(Electron transport material of single-layer type photosensitive layer)
The electron transport material represented by General Formula 1, General Formula 1-A, or General Formula 1-B used in the present invention has a structural skeleton shown below.

  <General formula 1>

｛但し、上記一般式中、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。｝
〈一般式１―Ａ〉

{However, in the above general formula, R1 and R2 are each independently 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. R 3, R 4, R 5, R 6, R 7, R 8, R 9, R 10 are each independently a hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted A group selected from the group consisting of a substituted cycloalkyl group and a substituted or unsubstituted aralkyl group. }
<General Formula 1-A>

｛ただし、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。｝
〈一般式１―Ｂ〉

{However, in the formula, 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, and a substituted or unsubstituted aralkyl group. , R3, 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 The group selected from the group which consists of an alkyl group, a substituted or unsubstituted cycloalkyl group, and a substituted or unsubstituted aralkyl group is represented, n is a repeating unit and represents the integer of 1-100. }
<General formula 1-B>

｛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。｝
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 R15 and R16 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 R17 , 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 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. Are included in the alkyl 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.

  Specifically, the electron transporting material represented by the general formula 1 is preferably an electron transporting material represented by the following structural formulas 2 to 8 in terms of high quality images. In the formula, Me represents a methyl group.

  (Structural formula 2)

（構造式３）

(Structural formula 3)

（構造式４）

(Structural formula 4)

（構造式５）

(Structural formula 5)

（構造式６）

(Structural formula 6)

（構造式７）

(Structural formula 7)

（構造式８）

(Structural formula 8)

一般式１で表される電子輸送材料の製造方法としては、下記の方法が例示できる。

Examples of the method for producing the electron transport material represented by the general formula 1 include the following methods.

  Naphthalenecarboxylic acid is synthesized from the following reaction formula according to a known synthesis method (for example, US Pat. No. 6,794,102, Industrial Organic Pigments 2nd edition, VCH, 485 (1997)).

「式中、ＲｎはＲ３、Ｒ４、Ｒ７、Ｒ８を表し、ＲｍはＲ５、Ｒ６、Ｒ９、Ｒ１０を表す。」
本発明に用いる一般式１で表される電子輸送材料は、上記のナフタレンカルボン酸若しくはその無水物をアミン類と反応させ、モノイミド化する方法、ナフタレンカルボン酸若しくはその無水物を緩衝液によりｐＨ調整してジアミン類と反応させる方法等により得られる。モノイミド化は無溶媒、若しくは溶媒存在下でおこなう。溶媒としては特に制限はないが、ベンゼン、トルエン、キシレン、クロロナフタレン、酢酸、ピリジン、メチルピリジン、ジメチルホルムアミド、ジメチルアセトアミド、ジメチルエチレンウレア、ジメチルスルホキサイド等原料や生成物と反応せず５０℃〜２５０℃の温度で反応させられるものを用いるとよい。ｐＨ調整には水酸化リチウム、水酸化カリウム等の塩基性水溶液をリン酸等の酸との混合により作製した緩衝液を用いる。カルボン酸とアミン類やジアミン類とを反応させて得られたカルボン酸誘導体脱水反応は無溶媒、若しくは溶媒存在下でおこなう。溶媒としては特に制限は無いがベンゼン、トルエン、クロロナフタレン、ブロモナフタレン、無水酢酸等原料や生成物と反応せず５０℃〜２５０℃の温度で反応させられるものを用いるとよい。いずれの反応も、無触媒若しくは触媒存在下でおこなってよく、特に限定されないが例えばモレキュラーシーブスやベンゼンスルホン酸やｐ−トルエンスルホン酸等を脱水剤として用いることが例示できる。

“In the formula, Rn represents R3, R4, R7, and R8, and Rm represents R5, R6, R9, and R10.”
The electron transport material represented by the general formula 1 used in the present invention is a method of reacting the above naphthalenecarboxylic acid or its anhydride with amines to monoimidize, adjusting the pH of the naphthalenecarboxylic acid or its anhydride with a buffer. Then, it is obtained by a method of reacting with diamines. 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 -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.

  The electron transport material represented by Structural Formula 4 can be produced by the following method.

(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 were placed and heated to reflux. 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. Furthermore, the recovered product was recrystallized with a toluene / hexane mixed solvent to obtain 2.08 g (yield 36.1%) of monoimide B.

(Second step)
In a 100 ml four-necked flask, add 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 heat to reflux for 5 hours. It was. 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 with a mixed solvent of toluene / ethyl acetate to obtain 0.810 g (yield 37.4%) of an electron transport material represented by the structural formula (4). In mass spectrometry (FD-MS), the peak of M / z = 614 was observed, and it was identified as the target product. In the elemental analysis, the calculated values are 66.45% carbon, 3.61% hydrogen, and 9.12% nitrogen, whereas the measured values are 66.28% carbon, 3.45% hydrogen, and 9.33 nitrogen. %there were.

  The electron transport material represented by Structural Formula 6 can be manufactured by the following method.

(First step)
In a 200 ml four-necked flask, 1,4,5,8-naphthalenetetracarboxylic dianhydride 10 g (37.3 mmol), hydrazine monohydrate 0.931 g (18.6 mmol), p-toluenesulfonic acid 20 mg, toluene 100 ml was 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. Furthermore, the recovered product was recrystallized with a mixed solvent of toluene / ethyl acetate to obtain 2.84 g of dimer C (yield 28.7%).

(Second step)
In a 200 ml four-necked flask, 5.0 g (9.39 mmol) of dimer C and 50 ml of DMF were placed and heated to reflux. To this, a mixture of 1.08 g (9.39 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 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 (yield 28.1%) of monoimide D.

(Third process)
In a 100 ml four-necked flask, 1.5 g (2.38 mmol) of monoimide D and 50 ml of DMF were placed 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. Furthermore, the recovered product was recrystallized with a toluene / hexane mixed solvent to obtain 0.276 g (yield 14.8%) of an electron transport material represented by the structural formula (6). In mass spectrometry (FD-MS), the peak of M / z = 782 was observed and identified as the target product. In the elemental analysis, calculated values are 70.57% carbon, 5.92% hydrogen, and 7.16% nitrogen, whereas measured values are 70.77% carbon, 6.11% hydrogen, and 7.02 nitrogen. %there were.

  Further, in addition to these electron transport materials, the electron transport material represented by the above general formula 1-B is further added to alleviate the shrinkage during film formation without reducing the charge transport capability, and aluminum deposited PET When a flexible sheet such as a sheet or a nickel belt is used as a support, it is possible to reduce warpage generally referred to as curl. Moreover, since the film becomes dense by the addition, there is an advantage that it is less susceptible to the influence of acid gas, that is, there is an effect that gas resistance is improved.

  In addition, since the film becomes dense, the wear resistance is also improved.

  Specific examples of the electron transport material represented by the general formula 1-B include the following compounds.

  (Structural formula 9)

（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).

  (Structural formula 10)

（ただし、式中、両端の末端基はＭｅ（メチル基）を表す。）
これらの電子輸送材料の添加量としては特に限定されるものではないが、好ましくは電子輸送材料全体量に対して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 addition amount of these electron transport materials is not particularly limited, but is preferably about 1% to 50%, and more preferably 5% to 30% with respect to the total amount of the electron 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.

  The electron transport material represented by the general formula 1-A is synthesized mainly by the following two synthesis methods.

一般式１―Ａで表される電荷輸送材料の繰り返し単位ｎは１から１００の整数である。

The repeating unit n of the charge transport material represented by the general formula 1-A is an integer of 1 to 100.

  The repeating unit n can be obtained by dividing the weight average molecular weight (Mw) in terms of standard polystyrene measured by GPC (gel permeation chromatography) by the molecular weight of the repeating unit. 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.

Specific examples of the charge transporting material represented by the general formula (1-A) include the following compounds (however, both end groups represent Me (methyl group) in the formula).
Specific examples of the electron transport material represented by the general formula 1-A include the following (Structural Formula 11)

（構造式１２）

(Structural formula 12)

（構造式１３）

(Structural formula 13)

前述の一般式１又は一般式１―Ｂであらわされる電子輸送材料を用いることが必須であるが、更にその他の電子輸送材料として、例えばクロルアニル、ブロムアニル、テトラシアノエチレン、テトラシアノキノジメタン、２，４，７―トリニトロ―９―フルオレノン、２，４，５，７―テトラニトロ―９―フルオレノン、２，４，５，７―テトラニトロキサントン、２，４，８―トリニトロチオキサントン、２，６，８―トリニトロ―４Ｈ―インデノ〔１，２―ｂ〕チオフェン―４―オン、１，３，７―トリニトロジベンゾチオフェン―５，５―ジオキサイド、下記構造式９、１０の化合物及びその誘導体などの電子受容性物質を１種以上組み合わせて用いても良い。

Although it is essential to use the electron transport material represented by the above general formula 1 or general formula 1-B, other electron transport materials include, for example, chloranil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2 , 4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6 , 8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, compounds of the following structural formulas 9 and 10 and derivatives thereof One or more electron-accepting substances such as these may be used in combination.

  (Structural formula 14)

（構造式１５）

(Structural formula 15)

（単層型感光層の正孔輸送材料）
正孔輸送物質としては、電子供与性物質が好ましく用いられる。

(Hole transport material for single-layer photosensitive layer)
As the hole transport material, an electron donating material is preferably used.

  Examples thereof include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, 9- (p-diethylaminostyrylanthracene), 1,1-bis- (4-dibenzylaminophenyl) propane, styrylanthracene, Examples include styrylpyrazolines, phenylhydrazones, α-phenylstilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, thiophene derivatives, and enamine derivatives.

  These hole transport materials may be used alone or as a mixture of two or more.

(Binder resin for single-layer photosensitive layer)
Examples of the polymer compound that can be used as the binder component include polystyrene, styrene / acrylonitrile copolymer, styrene / butadiene copolymer, styrene / maleic anhydride copolymer, polyester, polyvinyl chloride, and vinyl chloride / acetic acid. Vinyl copolymer, polyvinyl acetate, polyvinylidene chloride, polyarylate resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, acrylic resin, silicone resin, fluorine resin, epoxy resin, melamine resin, Thermoplastic or thermosetting resins such as urethane resin, phenol resin, alkyd resin and the like are mentioned, and polycarbonate resin is particularly preferable, but is not limited thereto.

  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.

  For the purpose of ensuring the stability of the single-layer type photosensitive layer against environmental fluctuations, when using an electrically inactive polymer compound, for example, polyester, polycarbonate, acrylic resin, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyethylene Polypropylene, fluororesin, polyacrylonitrile, acrylonitrile / styrene / butadiene copolymer, styrene / acrylonitrile copolymer, ethylene / vinyl acetate copolymer and the like are effective.

  Here, the electrically inactive polymer compound refers to a polymer compound that does not include a chemical structure exhibiting photoconductivity such as a triarylamine structure.

  When these resins are used in combination with a binder resin as an additive, the addition amount is preferably 50 wt% or less because of restrictions on light attenuation sensitivity.

(Additive)
To the extent that the object of the present invention is not impaired, the anti-oxidant, the plastic layer is applied to each layer such as a single-layer photosensitive layer, an undercoat layer, and a protective layer for the purpose of improving environmental resistance, reducing sensitivity, and preventing an increase in residual potential. Examples thereof include adding an agent, a lubricant, and an ultraviolet absorber.

  As the antioxidant that can be added to each layer, the following are preferable for the above purpose.

(A) Phenolic compounds 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, n-octadecyl-3- (4 '-Hydroxy-3', 5'-di-t-butylphenol), 2,2'-methylene-bis- (4-methyl-6-t-butylphenol), 2,2'-methylene-bis- (4- Ethyl-6-t-butylphenol), 4,4'-thiobis- (3-methyl-6-t-butylphenol), 4,4'-butylidenebis- (3-methyl-6-t-butylphenol), 1,1 , 3-Tris- (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4 -Hydroxybenzyl) benzene, te Lakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3′-bis (4′-hydroxy-3′-t-butyl) Phenyl) butyric acid] glycol ester, tocopherols.

(B) Paraphenylenediamines N-phenyl-N′-isopropyl-p-phenylenediamine, N, N′-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylene Diamine, N, N′-di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine.

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

(D) Organic sulfur compounds dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate.

(E) Organophosphorus compounds Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine.

  As the plasticizer that can be added to each layer, the following are preferred for the above purpose.

(A) Phosphate ester plasticizer Triphenyl phosphate, tricresyl phosphate, trioctyl phosphate, octyl diphenyl phosphate, trichloroethyl phosphate, cresyl diphenyl phosphate, tributyl phosphate, tri-2-ethylhexyl phosphate, Triphenyl phosphate.

(B) Phthalate ester plasticizers Dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dibutyl phthalate, diheptyl phthalate, di-2-ethylhexyl phthalate, diisooctyl phthalate, di-n-octyl phthalate, phthalate Dinonyl acid, diisononyl phthalate, diisodecyl phthalate, diundecyl phthalate, ditridecyl phthalate, dicyclohexyl phthalate, butyl benzyl phthalate, butyl lauryl phthalate, methyl oleyl phthalate, octyl decyl phthalate, dibutyl fumarate, dioctyl fumarate.

(C) Aromatic carboxylate plasticizers Trioctyl trimellitic acid, tri-n-octyl trimellitic acid, octyl oxybenzoate.

(D) Aliphatic dibasic ester plasticizers Dibutyl adipate, di-n-hexyl adipate, di-2-ethylhexyl adipate, di-n-octyl adipate, adipic acid-n-octyl-n-decyl , Diisodecyl adipate, dicapryl adipate, di-2-ethylhexyl azelate, dimethyl sebacate, diethyl sebacate, dibutyl sebacate, di-n-octyl sebacate, di-2-ethylhexyl sebacate, di-2 sebacate -Ethoxyethyl, dioctyl succinate, diisodecyl succinate, dioctyl tetrahydrophthalate, di-n-octyl tetrahydrophthalate.

(E) Fatty acid ester derivatives butyl oleate, glycerol monooleate, methyl acetylricinoleate, pentaerythritol ester, dipentaerythritol hexaester, triacetin, tributyrin.

(F) Oxyacid ester plasticizer Methyl acetyl ricinoleate, butyl acetyl ricinoleate, butyl phthalyl butyl glycolate, tributyl acetyl citrate.

(G) Epoxy plasticizer Epoxidized soybean oil, epoxidized linseed oil, epoxy butyl stearate, decyl epoxy stearate, octyl epoxy stearate, benzyl epoxy stearate, dioctyl epoxy hexahydrophthalate, didecyl epoxy hexahydrophthalate.

(H) Dihydric alcohol ester plasticizer diethylene glycol dibenzoate, triethylene glycol di-2-ethylbutyrate.

(I) Chlorinated plasticizer Chlorinated paraffin, chlorinated diphenyl, chlorinated fatty acid methyl, methoxychlorinated fatty acid methyl.

(J) Polyester plasticizer Polypropylene adipate, polypropylene sebacate, polyester, acetylated polyester.

(K) Sulfonic acid derivatives p-toluenesulfonamide, o-toluenesulfonamide, p-toluenesulfoneethylamide, o-toluenesulfoneethylamide, toluenesulfone-N-ethylamide, p-toluenesulfone-N-cyclohexylamide.

(L) Citric acid derivatives Triethyl citrate, triethyl acetyl citrate, tributyl citrate, tributyl acetyl citrate, tri-2-ethylhexyl acetyl citrate, acetyl citrate-n-octyldecyl.

(M) Others Terphenyl, partially hydrogenated terphenyl, camphor, 2-nitrodiphenyl, dinonylnaphthalene, methyl abietic acid.

  As the lubricant that can be added to each layer, the following are preferable for the above purpose.

(A) Hydrocarbon compound Liquid paraffin, paraffin wax, microwax, low-polymerized polyethylene.

(B) Fatty acid compounds Lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid.

(C) Fatty acid amide compounds Stearylamide, palmitylamide, oleinamide, methylenebisstearamide, ethylenebisstearamide.

(D) Ester compound Fatty acid lower alcohol ester, fatty acid polyhydric alcohol ester, fatty acid polyglycol ester.

(E) Alcohol compounds Cetyl alcohol, stearyl alcohol, ethylene glycol, polyethylene glycol, polyglycerol.

(F) Metal soap Lead stearate, cadmium stearate, barium stearate, calcium stearate, zinc stearate, magnesium stearate.

(G) Natural wax Carnauba wax, candelilla wax, beeswax, whale wax, ibotarou, montan wax.

(H) Others Silicone compounds and fluorine compounds.

  As the ultraviolet absorber that can be added to each layer, the following are preferable for the above purpose.

(A) Benzophenone series 2-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2,2 ′, 4-trihydroxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 2,2′-dihydroxy-4- Methoxybenzophenone.

(B) Salsylate type Phenyl salsylate, 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate.

(C) Benzotriazole type (2′-hydroxyphenyl) benzotriazole, (2′-hydroxy5′-methylphenyl) benzotriazole, (2′-hydroxy3′-tertiarybutyl 5′-methylphenyl) 5-chloro Benzotriazole.

(D) Cyanoacrylate-based ethyl-2-cyano-3,3-diphenyl acrylate, methyl 2-carbomethoxy 3 (paramethoxy) acrylate.

(E) Quencher (metal complex)
Nickel (2,2′thiobis (4-t-octyl) phenolate) normal butylamine, nickel dibutyldithiocarbamate, cobalt dicyclohexyldithiophosphate.

(F) HALS (hindered amine)
Bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1- [2- [3- (3 5-di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6 6-tetramethylpyridine, 8-benzyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro [4,5] undecane-2,4-dione, 4-benzoyloxy- 2,2,6,6-tetramethylpiperidine.

  Hereinafter, the present invention will be described by way of examples. However, this does not limit the scope of the present invention. All parts are parts by weight.

Electron transport material synthesis example 1
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 were added and heated to reflux. 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. Further, the recovered product was recrystallized from toluene / hexane to obtain 2.14 g of monoimide A (yield 31.5%).

Second Step In a 100 ml four-neck flask, 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 are placed for 5 hours. Heated to reflux. 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 electron transport material represented by the structural formula (2). (Referred to as electron transport material 1)
Structural formula 2

質量分析（ＦＤ−ＭＳ）において、Ｍ／ｚ＝７２６のピークが観測されたことにより目的物であると同定した。元素分析は計算値、炭素６９．４１％、水素５．２７％、窒素７．７１％に対し、実測値で炭素６９．５２％、水素５．０９％、窒素７．９３％あった。

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.

Electron transport material synthesis example 2
First Step: In a 200 ml four-necked flask, 10 g (37.3 mmol) of 1,4,5,8-naphthalenetetracarboxylic dianhydride and 0.931 g (18.6 mmol) of hydrazine monohydrate, p-toluenesulfonic acid 20 mg 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 of monoimide C (yield 38.5%).

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 0.186 g (1.62 mmol) of 2-aminoheptane and 5 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. Furthermore, the recovered product was recrystallized from toluene / hexane to obtain 0.243 g (yield 22.4%) of an electron transport material represented by the structural formula (3). (Referred to as electron transport material 2)
Structural formula 3

質量分析（ＦＤ―ＭＳ）において、Ｍ／ｚ＝６７０のピークが観測されたことにより目的物であると同定した。元素分析は計算値、炭素６８．０５％、水素４．５１％、窒素８．３５％に対し、実測値で炭素６８．２９％、水素４．７２％、窒素８．３３％あった。

In mass spectrometry (FD-MS), the peak of M / z = 670 was observed, and it 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.

Electron transport material synthesis example 3
First Step In a 200 ml four-necked flask, 5.0 g (9.39 mmol) of the above-mentioned dimer C and 50 ml of DMF were placed and heated to reflux. To this, a mixture of 2-aminoheptane 1.08 g (9.39 mmol) DMF 25 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 to obtain 1.66 g (yield 28.1%) of monoimide D.

Second Step In a 100 ml four-necked flask, 1.5 g (2.38 mmol) of monoimide D and 50 ml of DMF were placed and heated to reflux. A mixture of 2-aminooctane (0.308 g, 2.38 mmol) and DMF (10 ml) was added dropwise thereto 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 an electron transport material represented by the structural formula (5). (Referred to as electron transport material 3)
Structural formula 5

質量分析（ＦＤ―ＭＳ）において、Ｍ／ｚ＝７４０のピークが観測されたことにより目的物であると同定した。元素分析は計算値、炭素６９．７２％、水素５．４４％、窒素７．５６％に対し、実測値で炭素６９．５５％、水素５．２６％、窒素７．３３％あった。

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.

(Electron transport material synthesis example 4)
(Structural formula 11)

第一工程
２００ｍｌ４つ口フラスコに、１，４，５，８―ナフタレンテトラカルボン酸二無水物５．０ｇ（１８．６ｍｍｏｌ）、ＤＭＦ５０ｍｌを入れ、加熱還流させた。これに、２―アミノペンタン１．６２ｇ（１８．６ｍｍｏｌ）とＤＭＦ２５ｍｌの混合物を攪拌しながら滴下した。滴下終了後、６時間加熱還流させた。反応終了後、容器を冷却し、減圧濃縮した。残渣にトルエンを加え、シリカゲルカラムクロマトグラフィーにて精製した。更に回収品をトルエン／ヘキサンにより再結晶し、モノイミド体Ｅ ３．４９ｇ（収率４５．８％）を得た。

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 were 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. Furthermore, the recovered product was recrystallized with 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, hydrazine monohydrate The product 0.368 (7.33 mmol), p-toluenesulfonic acid 10 mg, and toluene 50 ml 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 an electron transport material 4 represented by the structural formula (A-1). 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 66.92% carbon, 3.67% hydrogen, and 8.99% nitrogen, and the measured values were 66.92% carbon, 3.74% hydrogen, and 9.05% nitrogen. (Referred to as electron transfer material 4)
(Pigment synthesis example 1)
A pigment was produced according to the method described in the production example of JP-A-2-8256 (Japanese Patent Publication No. 7-91486). That is, 9.8 g of phthalodinitrile and 75 ml of 1-chloronaphthalene are mixed with stirring, and 2.2 ml of titanium tetrachloride is added dropwise under a nitrogen stream. After completion of the dropping, the temperature was gradually raised to 200 ° C., and the reaction was carried out by stirring for 3 hours while maintaining the reaction temperature between 200 ° C. and 220 ° C. After completion of the reaction, the mixture was allowed to cool to 130 ° C. and filtered while hot, then washed with 1-chloronaphthalene until the powder turned blue, then washed several times with methanol, and further with hot water at 80 ° C. After washing twice, it was dried to obtain a pigment. (Referred to as pigment 1)
The obtained titanyl phthalocyanine powder was subjected to X-ray diffraction spectrum measurement under the following conditions and confirmed to be the same as the spectrum described in the publication.

(X-ray diffraction spectrum measurement conditions)
X-ray tube: Cu
Voltage: 50kV
Current: 30mA
Scanning speed: 2 ° / min Scanning range: 3 ° -40 °
Time constant: 2 seconds (Pigment synthesis example 2)
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 dropwise addition, the temperature was gradually raised to 180 ° C., and the reaction was carried out by stirring for 5 hours while maintaining the reaction temperature between 170 ° C. and 180 ° C. After 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. (Water paste) was obtained. 2 g of the obtained wet cake (water paste) was put into 20 g of tetrahydrofuran, stirred for 4 hours, filtered and dried to obtain titanyl phthalocyanine powder (referred to as pigment 2).

  The obtained titanyl phthalocyanine powder was measured for X-ray diffraction spectrum under the conditions of Pigment Synthesis Example 1, and the diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to Cu—Kα rays (wavelength 1.542 mm) described in the publication. ) Having a maximum diffraction peak at least 27.2 °, and further having main peaks at 9.4 °, 9.6 °, and 24.0 °, and the diffraction peak at the lowest angle side as 7. It was confirmed that the titanyl phthalocyanine had a peak at 3 ° and no peak between the peak at 7.3 ° and the peak at 9.4 °.

Photoconductor Preparation Example 1
Metal-free phthalocyanine was dispersed under the following composition and conditions to prepare a pigment dispersion.

Metal-free phthalocyanine pigment (Dainippon Ink and Chemicals Co., Ltd .: Fastogen Blue 8120B): 3 parts Cyclohexanone: 97 parts Dispersion was carried out at a rotation speed of 100 rpm for 5 hours using a PSZ ball of φ0.5 mm in a glass pot of φ9 cm.

  A photoconductor coating solution having the following composition was prepared using the dispersion.

The above dispersion: 80 parts Hole transport material of the following structural formula 16: 60 parts

電子輸送材料１：４０部
Ｚ型ポリカーボネート樹脂（帝人化成製：パンライトＴＳ―２０５０）：１００部
シリコーンオイル（信越化学工業社製：ＫＦ５０）：０．０２部
テトラヒドロフラン：７００部
こうして得られた感光層用塗工液をφ３０ｍｍ、長さ３４０ｍｍアルミニウムドラム上に、浸漬塗工法にて塗布、１２０℃で２０分間乾燥し、２５μｍの感光層を形成し、感光体ドラムを作製した。また同時に、この感光層用塗工液をアルミ板上にブレードコーターにて塗布、１２０℃で２０分間乾燥し、２５μｍの感光層を形成し、シート感光体を作製した（両感光体を感光体１とする）。
感光体作製例２〜１６
表１に示すように、電荷発生材料種、正孔輸送剤添加量（樹脂１００重量部に対する添加重量部）、電子輸送材料種及びその添加量（樹脂１００重量部に対する添加重量部）を変更したこと以外は感光体作製例１と同様にして感光体ドラム、シート感光体を作製し、感光体２〜１６を得た。

Electron transporting materials 1:40 parts Z-type polycarbonate resin (Teijin Kasei: Panlite TS-2050): 100 parts of a silicone oil (Shin-Etsu Chemical Co., Ltd.: KF50): 0.02 parts of tetrahydrofuran: obtained 700 parts of thus The photosensitive layer coating solution was applied on an aluminum drum having a diameter of 30 mm and a length of 340 mm by a dip coating method and dried at 120 ° C. for 20 minutes to form a photosensitive layer of 25 μm, thereby preparing a photosensitive drum. At the same time, this photosensitive layer coating solution was applied onto an aluminum plate with a blade coater and dried at 120 ° C. for 20 minutes to form a photosensitive layer of 25 μm, thereby producing a sheet photoreceptor (both photoreceptors were photoreceptors). 1) .
Photoconductor Preparation Examples 2 to 16 6
As shown in Table 1 , the charge generation material species, the hole transport agent addition amount (addition part by weight with respect to 100 parts by weight of the resin), the electron transport material type and the addition amount (addition part by weight with respect to 100 parts by weight of the resin) were changed. Except for this, photoconductor drums and sheet photoconductors were produced in the same manner as in Photoconductor Preparation Example 1 to obtain photoconductors 2 to 16.

Photoconductor preparation 17
A photoconductor drum and a sheet photoconductor were prepared in the same manner as in the photoconductor preparation example 4 except that the electron transport material 1 was changed to the electron transport material 4 in the photoconductor preparation example 4, and a photoconductor 17 was obtained. .

Photoconductor production 18
In Photoconductor Preparation Example 7, a photoconductor drum and a sheet photoconductor were prepared in the same manner as in Photoconductor Preparation Example 7, except that the electron transport material 1 was changed to the electron transport material 5 represented by the following structural formula. A photoreceptor 18 was obtained.

  (Electron transport material 5)

感光体作製１９
感光体作製例４において、電子輸送材料１を下記構造式で表される電子輸送材料６に変更したこと以外は、全て感光体作製例４と同様にして感光体ドラム、シート感光体を作製し、感光体１９を得た。
（電子輸送材料６）

Photoconductor preparation 19
In Photoconductor Preparation Example 4, a photoconductor drum and a sheet photoconductor were prepared in the same manner as in Photoconductor Preparation Example 4 except that the electron transport material 1 was changed to an electron transport material 6 represented by the following structural formula. A photoreceptor 19 was obtained.
(Electron transport material 6)

（式中ｎは１〜１００まで数値を表し、これらのものの混合体である。式中、両端の末端基はＭｅ（メチル基）を表す。）
感光体作製２０
感光体作製例７において、電子輸送材料１を５０重量部とし、下記構造式で表される電子輸送材料７を１０重量部加えたこと以外は、全て感光体作製例７と同様にして感光体ドラム、シート感光体を作製し、感光体２０を得た。

(In the formula, n represents a numerical value from 1 to 100 and is a mixture of these. In the formula, the end groups at both ends represent Me (methyl group).)
Photoconductor preparation 20
In Photoconductor Preparation Example 7, the photoconductor was prepared in the same manner as Photoconductor Preparation Example 7, except that 50 parts by weight of electron transport material 1 and 10 parts by weight of electron transport material 7 represented by the following structural formula were added. A drum and a sheet photoreceptor were prepared, and a photoreceptor 20 was obtained.

  (Electron transport material 7)

（式中、両端の末端基はＭｅ（メチル基）を表す。）

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

（感光体の光感度Ｅ１／２の評価）
得られたシート感光体を川口電気（株）製モデルＥＰＡ８１００に装着して、±８００Ｖ帯電させた後、７８０ｎｍの単色光による露光、除電を行い、それぞれの帯電極性における半減露光量（Ｅ１／２）を測定し、その比を求めた。その結果を表２及び３に示す。

(Evaluation of photosensitivity E1 / 2 of photoreceptor)
The obtained sheet photoreceptor was mounted on a model EPA8100 manufactured by Kawaguchi Electric Co., Ltd., charged with ± 800 V, exposed to 780 nm monochromatic light, and neutralized, and the half-exposure amount (E1 / 2 for each charged polarity). ) And the ratio was determined. The results are shown in Tables 2 and 3.

(Evaluation of transfer memory image)
A photoconductor was mounted on the image forming apparatus, a transfer memory evaluation document shown in FIG. 7 was output, and the density change due to the transfer memory was visually evaluated. The density of the portion affected by the transfer increases in the halftone image density region. The transfer memory image is evaluated before and after the printing durability test, and the evaluation rank is as follows .
A: Very good, B: Good, B: Somewhat inferior, X: Very bad (Evaluation of image exposure memory image)
A photoconductor was mounted on the image forming apparatus, an image exposure memory evaluation document shown in FIG. 8 was output, and the density change due to the image exposure memory was visually evaluated. The density of the portion affected by the strong image exposure increases in the halftone image density region. Image exposure memory image evaluation is performed before and after the printing durability test, and the evaluation rank is as follows .
A: Very good, O: Good, Δ: Slightly inferior, X: Very bad Examples 1 to 12, Reference Examples 13 to 15, Example 16 and Comparative Examples 1 to 4
Replacing the power pack of Ricoh's imgio Neo 270 (write laser wavelength is 780 nm, with neutralization LED), remodeling to roller charging (positive polarity) and roller transfer (negative polarity), changing to positive charging toner and developer The image forming apparatus 1 was mounted with the photoconductors 1 to 16, and a printing durability test was performed to print 10,000 sheets in total on the A4 side using a 5% writing rate chart. The charging potential of the photoconductor at the start of the test was set to be +600 V, and the test was performed under these charging conditions until the end of the test. The developing bias was + 450V. The test environment is 23 ° C. and 55% RH. Transfer and image exposure memory images were evaluated before and after the printing durability test. The results are shown in Table 2 .

実施例１７〜２４、参考例２５〜２７、実施例２８、比較例５〜８
リコー製ｉｍｇｉｏ Ｎｅｏ ２７０（書き込みレーザー波長は７８０ｎｍ、除電ＬＥＤ有り）のパワーパックを交換して、ローラー帯電（正極性）、ローラー転写（負極性）に改造し、除電ＬＥＤを外し、正帯電用トナー及び現像剤に変更した画像形成装置２に感光体１〜１６を搭載し、書き込み率５％チャートを用いＡ４横で通算１万枚印刷する耐刷試験を行った。試験開始時の感光体の帯電電位が＋６００Ｖとなるように設定し、試験終了に至るまでこの帯電条件で試験を行った。また現像バイアスは＋４５０Ｖとした。試験環境は２３℃、５５％ＲＨである。耐刷試験前後で転写及び像露光メモリー画像の評価を行った。その結果を表３に示す。

Examples 17 to 24, Reference Examples 25 to 27, Example 28 , Comparative Examples 5 to 8
Replacing Ricoh's imgio Neo 270 (write laser wavelength is 780 nm, with neutralization LED), remodeling to roller charging (positive polarity) and roller transfer (negative polarity), removing the neutralization LED, and positively charging toner The image forming apparatus 2 changed to the developer was mounted with the photoconductors 1 to 16, and a printing durability test was performed to print 10,000 sheets in total on the A4 side using a 5% writing rate chart. The charging potential of the photoconductor at the start of the test was set to be +600 V, and the test was performed under these charging conditions until the end of the test. The developing bias was + 450V. The test environment is 23 ° C. and 55% RH. Transfer and image exposure memory images were evaluated before and after the printing durability test. The results are shown in Table 3 .

実施例に示すように本発明の要件を満たす実施例では繰り返し使用によっても転写及び像露光による画像不具合が発生しておらず、良好な画像が出力できることが判明した。

As shown in the examples, in the examples satisfying the requirements of the present invention, it has been found that even when used repeatedly, image defects due to transfer and image exposure do not occur and a good image can be output.

Examples 29 to 33, Reference Examples 34 to 36, Example 37 , Comparative Examples 9 to 10
Ricoh's imgio Neo 270 (write laser wavelength is 780 nm, with neutralization LED), roller charging (negative polarity), roller transfer (negative positive polarity), and photosensitive to the image forming apparatus 3 changed to negative charging toner and developer. A printing durability test was performed in which the bodies 2, 4, 7, 10, 12, 14, and 16 were mounted, and a total of 10,000 sheets were printed on the A4 side using a 5% writing rate chart. The charging potential of the photoconductor at the start of the test was set to be −600 V, and the test was performed under these charging conditions until the end of the test. The developing bias was −450V. The test environment is 23 ° C. and 55% RH. Transfer and image exposure memory images were evaluated before and after the printing durability test. The results are shown in Table 4 .

尚、この時発生した像露光メモリー画像は、図９に示すようなネガ残像となった。比較例のように負の光感度が悪い場合、像露光により負の空間電荷が蓄積し、像露光部の中間調電位が上昇し、濃度低下が起こったものと考えられる。

The image exposure memory image generated at this time was a negative afterimage as shown in FIG. When the negative photosensitivity is poor as in the comparative example, it is considered that negative space charges are accumulated by image exposure, the halftone potential of the image exposure portion is increased, and the density is lowered.

Examples 38-42 , Reference Examples 43-45, Example 46 , Comparative Examples 11-12
Ricoh's imgio Neo 270 (write laser wavelength is 780 nm, with neutralization LED), roller charging (negative polarity) and roller transfer (negative positive polarity), with the neutralization LED removed and changed to negatively charged toner and developer Photosensitive members 2, 4, 7, 10, 12, 14, and 16 were mounted on the forming apparatus 3, and a printing durability test was performed to print a total of 10,000 sheets on the A4 side using a 5% writing rate chart. The photosensitive member was charged at a charging potential of 600 V at the start of the test, and the test was conducted under these charging conditions until the end of the test. The developing bias was −450V. The test environment is 23 ° C. and 55% RH. Transfer and image exposure memory images were evaluated before and after the printing durability test. The results are shown in Table 5 .

尚、この時発生した像露光メモリー画像は、図９に示すようなネガ残像となった。この理由は先述した通りと考えられる。

The image exposure memory image generated at this time was a negative afterimage as shown in FIG. The reason is considered as described above.

  Although the embodiments and examples of the present invention have been specifically described above, the present invention is not limited to these embodiments and examples, and these embodiments and examples of the present invention are not limited thereto. Can be changed or modified without departing from the spirit and scope of the present invention.

1 is a schematic cross-sectional view illustrating an example of an electrophotographic apparatus according to the present invention. It is a schematic cross section which shows another example of the electrophotographic apparatus which concerns on this invention. It is a schematic cross section which shows another example of the electrophotographic apparatus which concerns on this invention. It is a schematic cross section which shows another example of the electrophotographic apparatus which concerns on this invention. It is a schematic cross section which shows another example of the electrophotographic apparatus which concerns on this invention. It is sectional drawing which shows the layer structure of the electrophotographic photoreceptor which concerns on this invention. It is a figure which shows the evaluation original for transfer memory, and a transfer memory image. It is a figure which shows the evaluation original for image exposure memory, and an image exposure memory image. It is a figure which shows the image exposure memory image which generate | occur | produced.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Electrophotographic photosensitive member 12 Charging means 13 Exposure means 14 Developing means 15 Toner 16 Transfer means 17 Cleaning means 18 Image receiving medium 19 Fixing means 1A Electric discharge means 1B Pre-cleaning exposure means 1C Driving means 1D First transfer means 1E Second transfer Means 1F Intermediate transfer member 1G Image receiving medium carrier 21 Conductive support 22 Photosensitive layer

Claims (12)

In an electrophotographic photoreceptor having a photosensitive layer formed on a conductive support and having both positive and negative photosensitivity,
Photosensitive layer, a charge generating material and general formula

Wherein R 1 and R 2 are each independently 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. , R3, R4, R5, R6, R7, R8, R9 and R10 are each independently a hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, substituted or unsubstituted alkyl group, substituted or unsubstituted It is a group selected from the group consisting of a substituted cycloalkyl group and a substituted or unsubstituted aralkyl group.)
The in electron transporting material represented a free,
23 ° C., in 55% RH environment after the person electrophotographic photosensitive member surface potential was charged so as to 800V and -800 V, the half the surface potential wavelength is exposed at 780nm monochromatic light the exposure energy per unit surface area required to become, their respective E 1/2 (positive) When [μJ / cm ^2] and E1 / 2 (negative) [μJ / cm ^2], wherein
0.5 ≦ E1 / 2 (negative) / E1 / 2 (positive) ≦ 3
An electrophotographic photosensitive member characterized by satisfying the above . The electrophotographic photosensitive member according to claim 1, wherein the charge generation material is phthalocyanine. The electrophotographic photosensitive member according to claim 2 , wherein the phthalocyanine is titanyl phthalocyanine. The titanyl phthalocyanine, a diffraction peak of Bragg angle 2θ for Cu-K [alpha line (wavelength 1.542 Å) (± 0.2 °), has a maximum peak at 2 7.2 °, 9.4 °, 9 It has a peak to .6 ° and 24.0 °, 7. 3 ° a peak of the lowest angle side, the electrophotographic photosensitive of claim 3, characterized in that no peak between the 7.3 ° peak and the 9.4 ° peak body. The photosensitive layer, General formula

Wherein R15 and R16 are each independently 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. , R17, 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 and substituted or It is a group selected from the group consisting of unsubstituted aralkyl groups.)
The electrophotographic photosensitive member according to any one of claims 1 to 4, characterized in that it contains in represented by an electron transporting material further. An electrophotographic photoreceptor according to any one of claims 1 to 5 ,
A charging unit that Ru charges the electrophotographic photoreceptor,
And image exposure to the electrophotographic photosensitive member said charging, an image exposing means for forming an electrostatic latent image,
A developing means for forming a toner image by developing the electrostatic latent image formed on said electrophotographic photosensitive member with toner,
An image forming apparatus comprising a Turkey which having a transfer means to transfer onto the recording material a toner image image formed on the electrophotographic photoreceptor. It said charging means, an image forming apparatus according to claim 6, characterized in that makes charging the electrophotographic photosensitive member positively. It said charging means, an image forming apparatus according to claim 6, characterized in that makes charging the electrophotographic photoreceptor negative. The transfer means, the image forming apparatus according to any one of claims 6 to 8, characterized in that a shape Gallo Ra shape or a belt shape. Having the electrophotographic photosensitive member of multiple,
Each of the image forming apparatus according to any one of claims 6-9 wherein the sequentially superposed toner image of the electrophotographic monochrome formed on the photoreceptor and forming a color image. It said transfer means, said after transferring primary the electrophotographic photosensitive member on which is formed on the toner image on the intermediate transfer member, transferred secondarily onto the primary transferred toner image the recording material on the intermediate transfer member ,
11. The image forming apparatus according to claim 10 , wherein a color image is formed by sequentially superimposing monochromatic toner images formed on the respective electrophotographic photoreceptors on the intermediate transfer member. Process cartridge characterized by having an electrophotographic photosensitive member according to any one of claims 1 to 5.

Images