JP4567615B2 - Electrophotographic equipment - Google Patents

Description

  The present invention relates to an electrophotographic apparatus using a single-layer photoreceptor that operates at a time from a charged portion to a developing portion of 300 msec or less and includes at least a specific crystal type titanyl phthalocyanine and a specific charge transport material.

  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.

The electrophotographic photosensitive member used in these electrophotographic apparatuses is an organic photoconductive material having superiority in sensitivity, thermal stability, toxicity, and the like with respect to inorganic materials such as Se, CdS, and ZnO conventionally used as photoconductive materials. An electrophotographic photoreceptor using a conductive material has become mainstream. The electrophotographic photosensitive member using the organic photoconductive material mainly includes a function separation type photosensitive layer having a laminated structure including a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material. It is used for.
On the other hand, a single-layer photoconductor including a charge generation material and a charge transport material in a single photosensitive layer can be produced by a simple manufacturing process, and has improved optical characteristics due to fewer layer interfaces. In recent years, it has been attracting attention because of its advantages such as being usable in the charging process.

In recent years, there has been a demand for miniaturization and high speed of electrophotographic apparatuses. To reduce the size of the apparatus, it is indispensable to reduce the diameter of the photoreceptor, and to increase the speed, it is necessary to increase the photosensitive member linear velocity. In an electrophotographic apparatus, a uniformly charged photoconductor is irradiated with writing light modulated by image data to form an electrostatic latent image on the photoconductor, and this electrostatic latent image is formed. Since the toner is supplied to the photosensitive member by the developing unit and a toner image is formed on the photosensitive member and developed, from the writing unit (exposure unit) to the developing unit due to the reduction in the diameter of the photosensitive member and the increase in the linear velocity of the photosensitive member. The time is shortened. Therefore, when the sensitivity and responsiveness of the photosensitive member are not sufficient, the potential of the exposed portion in the developing portion is not stable because the potential of the image portion irradiated with light reaches the developing portion while the potential is being attenuated. As a result, problems such as uneven image density and reduced image density occur.
As described above, a photoconductor with high sensitivity and high speed response is required to reduce the size and speed of the device. However, conventional single-layer photoconductors are still inadequate. Therefore, an electrophotographic apparatus using a single-layer photoreceptor having higher sensitivity and responsiveness than ever is desired.

  The present invention has been made in view of the above-described prior art, and in an electrophotographic apparatus using a single-layer photosensitive member, stably outputs a high-quality image even when the apparatus is small and high-speed. It is an object of the present invention to provide an electrophotographic apparatus capable of performing the above.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that in an electrophotographic apparatus that is operated with a time from a charging unit to a developing unit of 300 msec or less, the photosensitive member is at least a characteristic X-ray of CuKα as a charge generating material. Titanyl phthalocyanine having a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to (wavelength 1.542 mm), and general formula (1) or general formula (2) as a charge transport material In a compact high-speed electrophotographic apparatus using a single-layer photoconductor, a stable and high-quality image can be obtained by using an electrophotographic apparatus comprising a single layer containing an electron transport material represented by I found out that I could get.

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わし、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わす。

In the formula, R1 and R2 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, R3, R4, R5, R6, R7, R8, R9, 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 cycloalkyl group Represents a group selected from the group consisting of a substituted or unsubstituted aralkyl group.

式中、Ｒ１、Ｒ２は、それぞれ独立に水素原子、置換又は無置換のアルキル基、置換又は無置換のシクロアルキル基、置換又は無置換のアラルキル基からなる群より選ばれる基を表わす。

In the formula, R 1 and R 2 each independently represent a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, and a substituted or unsubstituted aralkyl group.

The titanyl phthalocyanine used in the present invention has a very high carrier generation function, and the electron transport material represented by the general formula (1) or the general formula (2) used in the present invention is very high. It has a charge transfer function. Therefore, the single-layer photoreceptor containing the above titanyl phthalocyanine and the charge transport material has high sensitivity and high speed response.
However, although the above single-layer photoconductor has high sensitivity and high-speed response, the charge retention is not so good, that is, the dark decay is large, so when the time from the charged part to the developing part becomes long in the image forming process, As a result, the surface potential of the photosensitive member is greatly attenuated, and as a result, the potential of the background portion is lowered, and an abnormal image such as background staining or fogging is caused.
However, in an electrophotographic apparatus in which the time from the charging unit to the developing unit is 300 msec or less, a high-quality image can be obtained with almost no influence of dark attenuation even when the single-layer photoconductor is used.

That is, the said subject is solved by (1)-(10) of this invention shown below.
(1) “Photoconductor, charging device for uniformly charging the surface of the photoconductor, image exposure means for performing image exposure after uniform charging to form an electrostatic latent image, and developing the electrostatic latent image In an electrophotographic apparatus having a developing means for transferring and a transferring means for transferring a developed image, wherein the photosensitive member is operated at least 300 msec from the charging portion to the developing portion. As a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to a characteristic X-ray (wavelength 1.542 mm) of CuKα as a charge generation material, the photosensitive layer has a maximum diffraction peak at least 27.2 °. An electrophotographic apparatus comprising a single layer containing a titanyl phthalocyanine having an electron transport material represented by the following general formula (1) as a charge transport material;

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わし、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わす。」
（２）「感光体と、該感光体の表面を一様に帯電する帯電装置と、一様帯電後に像露光を行ない静電潜像を形成する像露光手段と、前記静電潜像を現像する現像手段と、現像像を転写する転写手段とを有し、帯電部から現像部までの時間が３００ｍｓｅｃ以下で動作される電子写真装置において、前記感光体が少なくとも導電性支持体上に感光層を設けて成り、該感光層が少なくとも電荷発生材料としてＣｕＫαの特性Ｘ線（波長１．５４２Å）に対するブラッグ角２θの回折ピーク（±０．２゜）として、少なくとも２７．２゜に最大回折ピークを有するチタニルフタロシアニン、電荷輸送材料として下記一般式（２）で表わされる電子輸送材料を含む単一の層からなることを特徴とする電子写真装置；

In the formula, R1 and R2 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, R3, R4, R5, R6, R7, R8, R9, 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 cycloalkyl group Represents a group selected from the group consisting of a substituted or unsubstituted aralkyl group. "
(2) “Photoconductor, charging device for uniformly charging the surface of the photoconductor, image exposure means for performing image exposure after uniform charging to form an electrostatic latent image, and developing the electrostatic latent image In an electrophotographic apparatus having a developing means for transferring and a transferring means for transferring a developed image, wherein the photosensitive member is operated at least 300 msec from the charging portion to the developing portion. As a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to a characteristic X-ray (wavelength 1.542 mm) of CuKα as a charge generation material, the photosensitive layer has a maximum diffraction peak at least 27.2 °. An electrophotographic apparatus comprising a single layer containing a titanyl phthalocyanine having an electron transport material represented by the following general formula (2) as a charge transport material;

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わす。」
（３）「前記チタニルフタロシアニンがＣｕＫαの特性Ｘ線（波長１．５４２Å）に対するブラッグ角２θの回折ピーク（±０．２゜）として、少なくとも２７．２゜に最大回折ピークを有し、更に９．４゜、９．６゜、２４．０゜に主要なピークを有し、かつ最も低角側の回折ピークとして７．３゜にピークを有し、７．３゜のピークと９．４゜のピークの間にピークを有さないことを特徴とする前記第（１）項又は第（２）項に記載の電子写真装置」
（４）「前記チタニルフタロシアニンの平均粒子径が０．２５μｍ以下であることを特徴とする前記第（３）項に記載の電子写真装置」
（５）「前記感光層に含まれる電荷輸送材料が、正孔輸送材料と電子輸送材料の両方を含むことを特徴とする前記第（１）項乃至第（４）項のいずれかに記載の電子写真装置」
（６）「前記正孔輸送材料が下記構造式（１）で表わされることを特徴とする前記第（１）項乃至第（５）項のいずれかに記載の電子写真装置；

In the formula, R 1 and R 2 each independently represent a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, and a substituted or unsubstituted aralkyl group. "
(3) “The titanyl phthalocyanine has a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 波長) of CuKα. It has major peaks at .4 °, 9.6 ° and 24.0 °, and has a peak at 7.3 ° as the lowest diffraction peak, a peak at 7.3 ° and 9.4 °. The electrophotographic apparatus according to (1) or (2), wherein there is no peak between the peaks of °.
(4) “The electrophotographic apparatus according to (3), wherein the titanyl phthalocyanine has an average particle size of 0.25 μm or less”
(5) The charge transporting material contained in the photosensitive layer contains both a hole transporting material and an electron transporting material, according to any one of (1) to (4), Electrophotographic device "
(6) The electrophotographic apparatus according to any one of (1) to (5), wherein the hole transport material is represented by the following structural formula (1):

」
（７）「正帯電で帯電プロセスを行なうことを特徴とする前記第（１）項乃至第（６）項のいずれかに記載の電子写真装置」
（８）「前記電子写真装置が複数の電子写真感光体を具備してなり、それぞれの電子写真感光体上に現像された単色のトナー画像を順次重ね合わせてカラー画像を形成することを特徴とする前記第（１）項乃至第（７）項のいずれかに記載の電子写真装置」
（９）「前記電子写真装置が、電子写真感光体上に現像されたトナー画像を中間転写体上に一次転写したのち、該中間転写体上のトナー画像を記録材上に二次転写する中間転写手段を有する電子写真装置であって、複数色のトナー画像を中間転写体上に順次重ね合わせてカラー画像を形成し、該カラー画像を記録材上に一括で二次転写することを特徴とする前記第（１）項乃至第（８）項のいずれかに記載の電子写真装置」
（１０）「前記画像形成要素が少なくとも、感光体と、帯電手段、現像手段及びクリーニング手段より選ばれる一つの手段とを一体に支持した着脱自在なプロセスカートリッジであることを特徴とする前記第（１）項乃至第（９）項のいずれかに記載の電子写真装置」

"
(7) “Electrophotographic apparatus according to any one of items (1) to (6), wherein the charging process is performed with positive charging”
(8) “The electrophotographic apparatus includes a plurality of electrophotographic photoreceptors, and a single color toner image developed on each electrophotographic photoreceptor is sequentially superimposed to form a color image. The electrophotographic apparatus according to any one of (1) to (7)
(9) “Intermediate transfer of the toner image developed on the electrophotographic photosensitive member onto the intermediate transfer member and then secondary transfer of the toner image on the intermediate transfer member onto the recording material. An electrophotographic apparatus having a transfer unit, wherein a plurality of color toner images are sequentially superimposed on an intermediate transfer member to form a color image, and the color image is secondarily transferred collectively onto a recording material. The electrophotographic apparatus according to any one of (1) to (8)
(10) wherein the image forming element is a detachable process cartridge integrally supporting at least a photosensitive member and one unit selected from a charging unit, a developing unit, and a cleaning unit. The electrophotographic apparatus according to any one of 1) to 9)

  According to the present invention, in an electrophotographic apparatus using a single-layer photosensitive member, high sensitivity and high speed response that can cope with the case where the time from the exposure section to the development section is shortened due to the small size and high speed of the apparatus. It is possible to provide an electrophotographic apparatus using the single-layer photoreceptor having the same.

Hereinafter, the electrophotographic apparatus of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic view for explaining an electrophotographic apparatus of the present invention, and modifications as will be described later also belong to the category of the present invention.
In FIG. 1, a photoconductor (11) is formed by providing at least a photoconductive layer on a conductive support, and the photoconductive layer is at least a diffraction peak having a Bragg angle 2θ with respect to a characteristic X-ray (wavelength 1.542 mm) of CuKα as a charge generating material. (± 0.2 °) as a single layer containing titanyl phthalocyanine having a maximum diffraction peak at least 27.2 °, and an electron transport material represented by the general formula (1) or (2) as a charge transport material Consists of. Although the photoconductor (11) has a drum shape, it may have a sheet shape or an endless belt shape.
The apparatus shown in FIG. 1 is operated in a time period of 300 msec or less from the charging unit of the charging device (charging unit) (12) to the developing unit of the developing unit (14). At this time, the time from the charging means to the developing means is obtained by dividing the circumference from the photosensitive member surface position facing the center of the charging unit to the photosensitive member surface facing the center of the developing unit by the photosensitive member linear velocity. It is required.
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. The charging means (12) is preferably used in contact with or in close proximity to the photoreceptor from the viewpoint of reducing power consumption. In particular, in order to prevent contamination of the charging means (12), a charging mechanism disposed in the vicinity of the photoreceptor having an appropriate gap between the photoreceptor and the surface of the charging means is desirable.
In the present invention, either positive or negative can be used as the polarity of the charge. However, the positive charge is more preferable than the negative charge because the chargeability is stable and the amount of ozone generated is small.
As the transfer means (16), the above charger can be generally used, but a combination of a transfer charger and a separation charger is effective.
The light source used for the exposure means (13), the charge removal means (1A), etc. includes fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light emitting diodes (LEDs), semiconductor lasers (LDs), electroluminescence ( EL) in general. Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.
The toner (15) developed on the photoreceptor by the developing means (14) is transferred to the image receiving medium (18), but not all is transferred, and toner remaining on the photoreceptor is also generated. 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.

FIG. 2 shows another example of an electrophotographic process according to the present invention. In FIG. 2, the photoconductor (11) satisfies the requirements of the present invention and has an endless belt shape.
Driven by drive means (1C), charged by charging means (12), image exposure by exposure means (13), development (not shown), transfer by transfer means (16), cleaning by pre-cleaning exposure means (1B). Pre-exposure, cleaning by the cleaning means (17), and static elimination by the static elimination means (1A) are 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).

  The above electrophotographic process exemplifies an embodiment 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 charge-removing exposure. 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. Also in this case, the photoconductor (11) is a photoconductor that satisfies the requirements of the present invention. Although the photoconductor (11) has a drum shape, it may have a sheet shape or an endless belt shape.

  FIG. 4 shows another example of the electrophotographic apparatus according to the present invention. In this electrophotographic apparatus, charging means (charging device) (12), exposure means (13), black (Bk), cyan (C), magenta (M), and yellow (Y) are disposed around the photoreceptor (11). Developing means (14Bk, 14C, 14M, 14Y) for each color toner, an intermediate transfer belt (1F) as an intermediate transfer member, and a cleaning means (17) are arranged in this order. Here, the subscripts Bk, C, M, and Y shown in the figure correspond to the color of the toner, and are added or omitted as appropriate.

  The photoreceptor (11) is an electrophotographic photoreceptor that satisfies the requirements of the present invention. Each color developing means (14Bk, 14C, 14M, 14Y) can be controlled independently, and only the color developing means for image formation is driven. The toner image formed on the photoreceptor (11) is transferred onto the intermediate transfer belt (1F) by the first transfer means (1D) disposed inside the intermediate transfer belt (1F). The first transfer means (1D) is arranged so as to be able to come into contact with and separate from the photoreceptor (11), and the intermediate transfer belt (1F) is brought into contact with the photoreceptor (11) only during the transfer operation. The respective color images are sequentially formed, and the toner images superimposed on the intermediate transfer belt (1F) are collectively transferred to the image receiving medium (18) by the second transfer means (1E) and then fixed by the fixing means (19). The image is formed by fixing. The second transfer means (1E) is also arranged so as to be able to contact and separate from the intermediate transfer belt (1F), and contacts the intermediate transfer belt (1F) only during the transfer operation.

  In the transfer drum type electrophotographic apparatus, since the toner images of the respective colors are sequentially transferred onto the transfer material electrostatically attracted to the transfer drum, there is a limitation on the transfer material that cannot be printed on cardboard, as shown in FIG. Such an intermediate transfer type electrophotographic apparatus has an advantage that the toner images of the respective colors are superimposed on the intermediate transfer body (1F), and thus are not limited by the transfer material. Such an intermediate transfer method is not limited to the apparatus shown in FIG. 4, but can be applied to the electrophotographic apparatus shown in FIGS. 1, 2, and 3 and FIG. 5 (a specific example is shown in FIG. 6) described later. it can.

  FIG. 5 shows another example of the 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 used in this electrophotographic apparatus is a photoreceptor that satisfies the requirements of the present invention. Around each photoconductor (11Y, 11M, 11C, 11Bk), charging means (12Y, 12M, 12C, 12Bk), exposure means (13Y, 13M, 13C, 13Bk), developing means (14Y, 14M, 14C, 14Bk), cleaning means (17Y, 17M, 17C, 17Bk) and the like are provided. Further, a transfer transfer belt (1G) as a transfer material carrier that comes in contact with and separates from each transfer position of each photoconductor (11Y, 11M, 11C, 11Bk) arranged on a straight line is hung by a driving means (1C). Has been passed. Transfer means (16Y, 16M, 16C, 16Bk) are disposed at transfer positions facing the respective photoconductors (11Y, 11M, 11C, 11Bk) with the conveyance transfer belt (1G) interposed therebetween.

Next, the electrophotographic photosensitive member used in the electrophotographic apparatus of the present invention will be described in detail.
FIG. 7 is a cross-sectional view schematically showing an example of an electrophotographic photosensitive member having the layer structure of the present invention, in which a photosensitive layer (22) is provided on a conductive support (21).
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, iron, tin oxide, An oxide such as indium oxide coated with film or cylindrical plastic or paper by vapor deposition or sputtering, or a plate of aluminum, aluminum alloy, nickel, stainless steel, etc., and drawing ironing method or impact ironing method It is possible to use pipes that have been surface-treated by cutting, superfinishing, polishing, etc. after being made into raw pipes by methods such as the Extruded Ironing method, Extruded Drawing method, and cutting method.

The photosensitive layer (22) in the present invention has a maximum diffraction of at least 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to a characteristic X-ray (wavelength 1.542 mm) of CuKα as a charge generating material. It consists of a single layer containing a titanyl phthalocyanine having a peak and an electron transport material represented by the general formula (1) or (2) as a charge transport material.
A titanyl phthalocyanine having a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 mm) of CuKα is disclosed in JP-A-2001-19871, It can be obtained by a known synthesis method described in Kaihei 11-5919, JP-A-3-269064, and the like.
The titanyl phthalocyanine has a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray of CuKα (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 ° What does not have a peak between peaks is preferable. The crystal form of this titanyl phthalocyanine is described in Japanese Patent Application Laid-Open No. 2001-019871, but when this titanyl phthalocyanine is used, it has very high sensitivity and the other has a maximum diffraction peak at 27.2 °. It is possible to obtain a photoreceptor having better charge retention than titanyl phthalocyanine having the above.
Further, a titanyl phthalocyanine crystal having the above crystal form and having an average primary particle size of 0.25 μm or less at the time of crystal synthesis or by dispersion filtration treatment and free of coarse particles (Japanese Patent Laid-Open No. 2004-83859, No. 2004-78141) is most useful. By using a titanyl phthalocyanine crystal having a small average particle size of primary particles, a dispersion having a small average particle size can be prepared. Usually, in a dispersion liquid, not all particles are present in the form of primary particles, but some primary particles are aggregated. Therefore, a dispersion liquid having a small average particle diameter can be prepared by setting the average particle size of the primary particles to 0.25 μm or less and using titanyl phthalocyanine crystals having no coarse particles. When the average particle diameter of titanyl phthalocyanine is large, the surface area of the titanyl phthalocyanine particle is decreased, and the amount of contact with the charge transport material is decreased, so that the carrier injection efficiency is decreased. In addition, when the average particle size is large, the probability of coating film defects in the photosensitive layer (charge generation layer) increases, and there is a problem that image defects such as background stains are likely to occur. Therefore, as the average particle size is smaller, an electrophotographic photosensitive member having higher sensitivity and higher stability against soiling can be obtained. This effect is particularly remarkable when the average particle size is 0.25 μm or less.
The average particle diameter here is a volume average particle diameter in the dispersion (coating liquid for charge generation layer), and was determined by an ultracentrifugal automatic particle size distribution analyzer: CAPA-700 (manufactured by Horiba). Is. At this time, the particle size (Median system) corresponding to 50% of the cumulative distribution was calculated. However, this method may not be able to detect a very small amount of coarse particles. Therefore, in order to obtain more details, it is important to observe the titanyl phthalocyanine crystal powder or dispersion directly with an electron microscope and determine its size. It is.

  Further, since the electron transport materials represented by the general formula (1) and the general formula (2) have a very excellent charge transport function, a photoconductor having high sensitivity and high speed response can be obtained by combining with the above titanyl phthalocyanine. Can do.

  A known charge generating material can be used together with the photoreceptor used in the present invention. 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 oxadiazole skeleton, an azo pigment having a bisstilbene skeleton, an azo pigment having a distyryl oxadiazole skeleton, an azo pigment having a distyrylcarbazole skeleton 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 alone or as a mixture of two or more.

Next, the charge transport material will be described.
The electron transport material represented by the general formula (1) used in the present invention has a structural skeleton shown below.

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わし、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わす。

In the formula, R1 and R2 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, R3, R4, R5, R6, R7, R8, R9, 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 cycloalkyl group Represents a group selected from the group consisting of a substituted or unsubstituted aralkyl group.

  Moreover, the electron transport material represented by General formula (2) used for this invention has the structural skeleton shown below.

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わす。

In the formula, R 1 and R 2 each independently represent a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, and a substituted or unsubstituted aralkyl group.

The substituted or unsubstituted alkyl group is an alkyl group having 1 to 25 carbon atoms, preferably 1 to 10 carbon atoms, specifically a methyl group, an ethyl group, an n-propyl group, an n- Straight chain such as butyl group, n-pentyl group, n-hexyl group, n-peptyl group, n-octyl group, n-nonyl group, n-decyl group, i-propyl group, s-butyl group, t -Branched group such as butyl group, methylpropyl group, dimethylpropyl group, ethylpropyl group, diethylpropyl group, methylbutyl group, dimethylbutyl group, methylpentyl group, dimethylpentyl group, methylhexyl group, dimethylhexyl group, alkoxy Alkyl group, monoalkylaminoalkyl group, dialkylaminoalkyl group, halogen-substituted alkyl group, alkylcarbonylalkyl group, Kishiarukiru group, alkanoyloxy group, an aminoalkyl group, esterified optionally alkyl group substituted with a carboxyl group which have an alkyl group substituted by a cyano group are exemplified.
The substitution position of these substituents is not particularly limited, and a group in which a part of carbon atoms of the substituted or unsubstituted alkyl group is substituted with a hetero atom (N, O, S, etc.) is also substituted. Included in the alkyl group.

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

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

  More specifically, an electron transport material represented by the following formula (1-1), formula (1-2), and formulas (2-1) to (2-5) has a high quality image. Is preferable. In the formula, Me represents a methyl group.

Examples of the method for producing the electron transport material represented by the general formula (1) or the general formula (2) 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を表わし、ＲｍはＲ５、Ｒ６、Ｒ９、Ｒ１０を表わす。

In the formula, Rn represents R3, R4, R7, R8, and Rm represents R5, R6, R9, R10.

  The electron transport material represented by the general formula (1) or the general formula (2) used in the present invention is a method of reacting the naphthalenecarboxylic acid or an anhydride thereof with an amine to monoimidize, an naphthalenecarboxylic acid or an anhydride thereof. It can be obtained by adjusting the pH of the product with a buffer solution and 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 without 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 charge transport material includes an electron transport material that transports electrons and a hole transport material that transports holes, and the photoreceptor used in the present invention includes an electron transport material and a hole transport material as charge transport materials. It is preferable to include both.
In the present invention, it is essential to include the electron transport material represented by the general formula (1) or the general formula (2). In addition, a known charge transport material, that is, an electron transport material or a hole transport material is added. It can also be used together.
Examples of the electron transport material include chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron accepting substances such as nitrodibenzothiophene-5,5-dioxide.
These electron transport materials may be used alone or as a mixture of two or more.

As the hole transport material, an electron donating substance 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, and thiophene derivatives.
These hole transport materials may be used alone or as a mixture of two or more. Among them, an α-phenylstilbene derivative having the following skeleton is preferable because of its excellent charge transport function.

（式中、Ｒ_１、Ｒ_２、Ｒ_３およびＲ_４は水素元素、置換もしくは無置換の低級アルキル樹、置換もしくは無置換のアリール基を表わし、Ａｒ_１は置換又は無置換のアリール基を表わし、Ａｒ_２置換又は無置換のアリーレン基を表わし、Ａｒ_１とＲ_１は共同で環を形成してもよく、またｎは０又は１の整数である。）
上記一般式で表わされる正孔輸送材料の中でも、特に下記構造式（１）で表わされる正孔輸送材料が特に好ましい。

(Wherein R ₁ , R ₂ , R ₃ and R ₄ represent a hydrogen element, a substituted or unsubstituted lower alkyl tree, a substituted or unsubstituted aryl group, and Ar ₁ represents a substituted or unsubstituted aryl group. represents Ar ₂ substituted or unsubstituted arylene group, Ar ₁ and R ₁ may be linked to form a ring, and n is an integer of 0 or 1.)
Among the hole transport materials represented by the above general formula, a hole transport material represented by the following structural formula (1) is particularly preferable.

As the polymer compound that can be used as the binder component of these photosensitive layers, known compounds can be used. For example, polystyrene, styrene / acrylonitrile copolymer, styrene / butadiene copolymer, styrene / maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride / vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, Thermoplastic such as polyarylate resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, acrylic resin, silicone resin, fluororesin, epoxy resin, melamine resin, urethane resin, phenol resin, alkyd resin Although thermosetting resin is mentioned, it is not limited to these.
Among these polymer compounds, polycarbonate resin is particularly preferable from the viewpoint of film quality.
When these resins are used in combination with a binder resin as an additive, the addition amount is preferably 20 to 80 wt% because of limitations on light attenuation sensitivity and film formation.

  As a method for forming the photosensitive layer, a casting method from a solution dispersion system is preferable. In order to provide a photosensitive layer by a casting method, the above-described charge generating material is dispersed by a ball mill, an attritor, a sand mill, or the like using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, or butanone together with a binder resin if necessary. A coating liquid prepared by adding a charge transporting material and a binder resin to the liquid may be prepared to an appropriate concentration and applied. The coating can be performed by a dip coating method, a spray coating method, a bead coating method, or the like.

Examples of the dispersion solvent that can be used in preparing the photosensitive layer coating solution provided as described above include ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone, and 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.
In the photosensitive layer, the charge generating material is 0.1 to 30% by weight, preferably 0.5 to 10% by weight, based on the entire photosensitive layer. The electron transport material is suitably 5 to 300 parts by weight, preferably 10 to 150 parts by weight, based on 100 parts by weight of the binder resin component. However, the electron transport material represented by the general formula (1) or the general formula (2) is preferably 50 to 100% by weight with respect to the entire electron transport material. The hole transport material is suitably 5 to 300 parts by weight, preferably 20 to 150 parts by weight with respect to 100 parts by weight of the binder resin component. When the electron transport material and the hole transport material are used in combination, the total amount of the electron transport material and the hole transport material is 20 to 300 parts by weight, preferably 30 to 200 parts by weight with respect to 100 parts by weight of the binder resin component. It is.

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, and the amount of the leveling agent used is 100 parts by weight of the polymer compound. On the other hand, about 0.001 to 5 parts by weight is appropriate.
The film thickness of the photosensitive layer is suitably about 5 to 40 μm, preferably about 15 to 35 μm.

As shown in FIG. 8, the electrophotographic photosensitive member used in the present invention may be provided with an undercoat layer (23) between the conductive support (21) and the photosensitive layer (22). The undercoat layer is provided for the purpose of improving adhesion, 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 above-described photosensitive layer.

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 is provided by anodic oxidation, organic materials such as polyparaxylylene (parylene), and inorganic materials such as silicon oxide, tin oxide, titanium oxide, ITO, ceria are provided by the 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.
In the present invention, an antioxidant, a plasticizer, an ultraviolet absorber, and a leveling agent can be added to the photosensitive layer in order to improve gas barrier properties and environmental resistance.

Hereinafter, the present invention will be described by way of examples. Note that this does not limit the scope of the present invention. All parts are parts by weight.
First, a synthesis example of a charge generation material (titanyl phthalocyanine crystal) will be described.
-Synthesis of titanyl phthalocyanine crystals-
(Pigment synthesis example 1)
A pigment was prepared according to Japanese Patent Application Laid-Open No. 2001-19871. That is, 29.2 g of 1,3-diiminoisoindoline and 200 ml of sulfolane are mixed, and 20.4 g of titanium tetrabutoxide is added dropwise under a nitrogen stream. After completion of the dropwise addition, the temperature was gradually raised to 180 ° C., and the reaction was carried out by stirring for 5 hours while maintaining the reaction temperature between 170 ° C. and 180 ° C. After the reaction is completed, the mixture is allowed to cool, and then the precipitate is filtered, washed with chloroform until the powder turns blue, then washed several times with methanol, then washed several times with hot water at 80 ° C. and dried. Crude titanyl phthalocyanine was obtained. Crude titanyl phthalocyanine is dissolved in 20 times the amount of concentrated sulfuric acid, added dropwise to 100 times the amount of ice water with stirring, the precipitated crystals are filtered, and then ion-exchanged water (pH: 7. 0, specific conductivity: 1.0 μS / cm) Repeated washing with water (pH value of ion-exchanged water after washing was 6.8, specific conductivity was 2.6 μS / cm), wet of titanyl phthalocyanine pigment A cake (water paste) was obtained. 40 g of the obtained wet cake (water paste) was put into 200 g of tetrahydrofuran, stirred for 4 hours, filtered and dried to obtain titanyl phthalocyanine powder. This is designated as Pigment 1.
The solid content concentration of the wet cake was 15% by mass. The crystal conversion solvent was used in a mass ratio of 33 times that of the wet cake. In addition, the halogen-containing compound is not used for the raw material of the pigment synthesis example 1.
The obtained titanyl phthalocyanine powder was subjected to X-ray diffraction spectrum measurement under the following conditions. As a result, the Bragg angle 2θ with respect to Cu-Kα ray (wavelength 1.542Å) was 27.2 ± 0.2 °, and the maximum peak and minimum angle 7 .3 ± 0.2 ° peak, 9.4 °, 9.6 °, 24.0 ° main peaks, 7.3 ° peak and 9.4 ° peak A titanyl phthalocyanine powder having no peak in between was obtained. The result is shown in FIG.

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

(Pigment synthesis example 2)
-Synthesis of titanyl phthalocyanine crystals-
An aqueous paste of titanyl phthalocyanine pigment was synthesized according to the method of Pigment Synthesis Example 1, and crystal conversion was performed as follows to obtain phthalocyanine crystals having smaller primary particles than in Pigment Synthesis Example 1.
According to JP 2004-83859 A and Example 1, 400 parts by mass of tetrahydrofuran was added to 60 parts by mass of the water paste before crystal conversion obtained in Pigment Synthesis Example 1, and a homomixer (Kennis, MARK IIf model at room temperature) was added. ) Was vigorously stirred (2000 rpm), and when the dark blue color of the paste changed to light blue (20 minutes after the start of stirring), the stirring was stopped and immediately filtered under reduced pressure. The crystals obtained on the filter were washed with tetrahydrofuran to obtain a pigment wet cake. This was dried under reduced pressure (5 mmHg) at 70 ° C. for 2 days to obtain 8.5 parts by mass of titanyl phthalocyanine crystals. This is designated as Pigment 2. The raw material of Pigment Synthesis Example 1 does not use a halogen-containing compound. The solid content concentration of the wet cake was 15% by mass. The crystal conversion solvent was used in a mass ratio of 44 times that of the wet cake.
A portion of titanyl phthalocyanine (water paste) before crystal conversion prepared in Pigment Synthesis Example 1 was diluted with ion-exchanged water to approximately 1% by mass, and the surface was scooped with a copper net having been subjected to conductive treatment. The particle diameter of phthalocyanine was observed with a transmission electron microscope (TEM, Hitachi: H-9000NAR) at a magnification of 75000 times. The average primary particle size was determined as follows.

The TEM image observed as described above is taken as a TEM photograph, and 30 titanyl phthalocyanine particles (a shape close to a needle shape) projected are arbitrarily selected, and the size of each major axis is measured. An arithmetic average of the major diameters of the measured 30 individuals was determined and used as the average particle size of the primary particles. The average particle size of the primary particles in the water paste in Pigment Synthesis Example 1 determined by the above method was 0.06 μm.
In addition, the titanyl phthalocyanine crystal after crystal conversion just before filtration in Pigment Synthesis Example 1 and Pigment Synthesis Example 2 was diluted with tetrahydrofuran so as to be about 1% by mass, and observed in the same manner as described above. Table 1 shows the average particle size of the primary particles obtained as described above. In addition, the titanyl phthalocyanine crystals produced in Pigment Synthesis Example 1 and Pigment Synthesis Example 2 did not necessarily have the same shape of all crystals (a shape close to a triangle, a shape close to a square, etc.). For this reason, the calculation was performed with the length of the largest diagonal line of the crystal as the major axis.

顔料合成例２で作製した顔料２は、前述と同様の方法でＸ線回折スペクトルを測定した。その結果、顔料合成例２で作製した顔料２のＸ線回折スペクトルは、顔料合成例１で作製した顔料１のスペクトルと一致した。

Pigment 2 produced in Pigment Synthesis Example 2 was measured for an X-ray diffraction spectrum by the same method as described above. As a result, the X-ray diffraction spectrum of Pigment 2 prepared in Pigment Synthesis Example 2 matched the spectrum of Pigment 1 prepared in Pigment Synthesis Example 1.

(Pigment synthesis example 3)
In accordance with the method described in Production Example 1 of JP-A-3-269064 (Japanese Patent No. 2854682), a pigment was prepared. That is, the wet cake prepared in Synthesis Example 1 was dried, and 1 g of the dried product was stirred for 1 hour (50 ° C.) in a mixed solvent of 10 g of ion-exchanged water and 1 g of monochlorobenzene, and then washed with methanol and ion-exchanged water. And dried to obtain a pigment (referred to as pigment 3).
The obtained titanyl phthalocyanine powder was measured for an X-ray diffraction spectrum under the above conditions, and confirmed to be the same as the spectrum described in the publication.

(Pigment Synthesis Example 4)
A pigment was prepared according to the method described in Example 1 of JP-A-11-5919 (Japanese Patent No. 3003664). That is, 20.4 parts of O-phthalodinitrile and 7.6 parts of titanium tetrachloride were heated and reacted in 50 parts of quinoline at 200 ° C. for 2 hours, and then the solvent was removed by steam distillation, followed by a 2% aqueous chloride solution, The resultant was purified with a 2% aqueous sodium hydroxide solution, washed with methanol and N, N-dimethylformamide, and then dried to obtain titanyl phthalocyanine. 2 parts of this titanyl phthalocyanine is dissolved little by little in 40 parts of 98% sulfuric acid at 5 ° C., and the mixture is stirred for about 1 hour while maintaining the temperature at 5 ° C. or less. Subsequently, the sulfuric acid solution is slowly poured into 400 parts of ice water stirred at a high speed, and the precipitated crystals are filtered. The crystals are washed with distilled water until no acid remains, and a wet cake is obtained. The cake was stirred in 100 parts of THF for about 5 hours, filtered, washed with THF and dried to obtain a pigment (referred to as pigment 4).
The obtained titanyl phthalocyanine powder was measured for an X-ray diffraction spectrum under the above conditions, and confirmed to be the same as the spectrum described in the publication.

(Photoreceptor Preparation Example 1)
The pigment 1 prepared in Pigment Synthesis Example 1 was dispersed under the following composition and conditions to prepare a pigment dispersion.
Titanyl phthalocyanine (pigment 1) 3 parts Cyclohexanone 97 parts A PSZ ball with a diameter of 0.5 mm was placed in a glass pot with a diameter of 9 cm and dispersed at a rotation speed of 100 rpm for 5 hours.
The average particle diameter in the pigment dispersion using the titanyl phthalocyanine of Pigment 1 was measured by CAPA-700 manufactured by Horiba, Ltd. and found to be 0.35 μm.
A photoconductor coating solution having the following composition was prepared using the dispersion.
Dispersion: 60 parts Hole transport material of the following structural formula (1) 30 parts Electron transport material of the following structural formula (2) 20 parts Z-type polycarbonate resin 50 parts (Teijin Chemicals: Panlite TS-2050)
0.01 parts of silicone oil (Shin-Etsu Chemical Co., Ltd .: KF50)
Tetrahydrofuran 350 parts

In addition, the electron transport material of the said Structural formula (2) was manufactured with 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 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>
Into a 100 ml four-necked 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 were heated and refluxed 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. Furthermore, the recovered product was recrystallized from toluene / ethyl acetate to obtain 0.668 g (yield 33.7%) of an electron transport material represented by the structural formula (2).
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.

  The photosensitive layer coating solution thus obtained was applied onto 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 25 μm photosensitive layer to obtain a photoreceptor. (Referred to as photoreceptor 1)

(Photoreceptor preparation example 2)
A photoconductor was obtained in the same manner as in Photoconductor Preparation Example 1 except that Pigment 2 prepared in Pigment Synthesis Example 2 was used instead of Pigment 1 used in Photoconductor Preparation Example 1 (referred to as Photoconductor 2).
The average particle size in the pigment dispersion using the titanyl phthalocyanine of Pigment 2 was measured by CAPA-700 manufactured by Horiba, Ltd. and found to be 0.20 μm.

(Photoreceptor Preparation Example 3)
A photoconductor was obtained in the same manner as in Photoconductor Preparation Example 1 except that Pigment 3 prepared in Pigment Synthesis Example 3 was used instead of Pigment 1 used in Photoconductor Preparation Example 1 (referred to as Photoconductor 3).

(Photosensitive member production example 4)
A photoconductor was obtained in the same manner as in Photoconductor Preparation Example 1 except that Pigment 4 prepared in Pigment Synthesis Example 4 was used instead of Pigment 1 used in Photoconductor Preparation Example 1 (referred to as Photoconductor 4).

(Photoreceptor Preparation Example 5)
A photoconductor was obtained in the same manner as in Photoconductor Preparation Example 1 except that X-type metal-free phthalocyanine (Dainippon Ink: Fastgen Blue 8120) was used instead of Pigment 1 used in Photoconductor Preparation Example 1 (Photoconductor 5). To do).

(Photosensitive member preparation example 6)
A photoconductor was obtained in the same manner as in Photoconductor Preparation Example 1 except that a bisazo pigment having the following structural formula (3) was used instead of the pigment 1 used in Photoconductor Preparation Example 1 (referred to as Photoconductor 6).

(Photoreceptor Preparation Example 7)
A photoconductor was obtained in the same manner as in Photoconductor Preparation Example 1 except that a hole transport material of the following structural formula (4) was used instead of the hole transport material used in Photoconductor Preparation Example 1 (Photoconductor 7). And).

(Photoreceptor Preparation Example 8)
A photoconductor was obtained in the same manner as in Photoconductor Preparation Example 1 except that a hole transport material of the following structural formula (5) was used instead of the hole transport material used in Photoconductor Preparation Example 1 (Photoconductor 8). And).

(Photoreceptor Preparation Example 9)
A photoconductor was obtained in the same manner as in Photoconductor Preparation Example 1 except that an electron transport material represented by the following structural formula (6) was used instead of the electron transport material used in Photoconductor Preparation Example 1 (referred to as Photoconductor 9). ).

In addition, the electron transport material of the said Structural formula (6) was manufactured 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 from toluene / hexane to obtain 2.08 g of monoimide B (yield 36.1%).
<Second step>
In a 100 ml four-necked flask, 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 are heated and refluxed 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 from toluene / ethyl acetate to obtain 0.810 g (yield 37.4%) of the electron transport material represented by the structural formula (6).
In mass spectrometry (FD-MS), the peak of M / z = 614 was observed and identified as the target product. In the elemental analysis, the calculated values were 66.45% carbon, 3.61% hydrogen, and 9.12% nitrogen, and the measured values were 66.28% carbon, 3.45% hydrogen, and 9.33% nitrogen.

(Photoreceptor Preparation Example 10)
A photoconductor was obtained in the same manner as in Photoconductor Preparation Example 1 except that an electron transport material represented by the following structural formula (7) was used instead of the electron transport material used in Photoconductor Preparation Example 1 (referred to as Photoconductor 10). ).

(Photoreceptor Preparation Example 11)
A photoconductor was obtained in the same manner as in Photoconductor Preparation Example 1 except that an electron transport material represented by the following structural formula (8) was used instead of the electron transport material used in Photoconductor Preparation Example 1 (referred to as Photoconductor 11). ).

Examples 1-14, Comparative Examples 1-15
The photoconductor produced as described above is remodeled from Ricoh's IPSiO Color 8100 (the power pack is replaced to be positively charged, and the LD wavelength used for writing is replaced with one of 780 nm, further freeing the process linear velocity. Device), adjusting the process linear speed of the device so that the charge-development time is 100 msec, 250 msec, and 350 msec, and evaluating the image (image density, presence / absence of image unevenness, background smudge) Was done.
The toner and developer used were changed from a dedicated one for IPSiO Color 8100 to a toner and developer having opposite polarity.
The charging means of the electrophotographic apparatus used an external power source, and the voltage applied to the charging roller was selected as an AC component with a peak-to-peak voltage of 1.9 kV and a frequency of 1.35 kHz. In addition, a bias was set for the DC component so that the charging potential of the photoreceptor was + 700V. The developing bias was + 500V. The test environment was 24 ° C./54% RH.
When the charging / development time is 100 msec, 250 msec, and 350 msec in the IPSiO Color 8100 modified machine, the exposure-development time is about 70 msec, 175 msec, and 245 msec, respectively.

The image evaluation method is as follows.
(Image density, image unevenness)
A solid black image was output to obtain a sufficient image density, and the presence or absence of image unevenness was evaluated. The evaluation rank is as follows.
・ Image density:
○: Sufficient image density is obtained Δ: Slightly thin ×: Sufficient image density cannot be obtained ・ Image unevenness:
○: No image irregularity △: Slightly observed ×: Clearly observed (dirt)
A blank paper image was output and the background stain was evaluated. The evaluation rank is as follows.
○: No dirt
Δ: Slightly observed ×: Clearly observed The above results are summarized in Table 2.

本発明の要件を満たす感光体を用い、帯電から現像までの時間が３００ｍｓｅｃ以下である実施例１〜１４の画像はいずれも良好なものであることがわかる。さらに本発明の要件を満たす感光体を用いた場合、露光現像時間が７０ｍｓｅｃとかなり短くなった場合においても良好な画像を得ることができ、装置の小型化、高速化に対応できることがわかる。
一方、本発明の要件を満たす感光体を用いた場合でも帯電−現像時間が本発明の範囲外である３００ｍｓｅｃ以上の場合には地汚れが発生し、良好な画像を得ることができない。
一方、比較例１〜１５から、本発明の範囲外である感光体を用いた場合には、露光現像時間が比較的長い時には比較的良好な画像が得られるが、露光現像時間が短くなった場合には十分な画像濃度を得ることができず、装置の小型化や高速化に対応できないことがわかる。

It can be seen that the images of Examples 1 to 14 in which the time from charging to development is 300 msec or less using a photoconductor satisfying the requirements of the present invention are all good. Furthermore, it can be seen that when a photoreceptor satisfying the requirements of the present invention is used, a good image can be obtained even when the exposure and development time is as short as 70 msec, and the apparatus can be made smaller and faster.
On the other hand, even when a photoconductor satisfying the requirements of the present invention is used, if the charge-development time is 300 msec or more, which is outside the range of the present invention, background staining occurs and a good image cannot be obtained.
On the other hand, from Comparative Examples 1 to 15, when using a photoreceptor that is outside the scope of the present invention, a relatively good image can be obtained when the exposure development time is relatively long, but the exposure development time is shortened. In this case, it is understood that a sufficient image density cannot be obtained, and the apparatus cannot be reduced in size and speed.

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 a schematic cross section which shows another example of the electrophotographic apparatus which concerns on this invention. It is sectional drawing which shows the example of the layer structure of the electrophotographic photoreceptor which concerns on this invention. It is sectional drawing which shows the example of another layer structure of the electrophotographic photoreceptor which concerns on this invention. It is a X-ray diffraction spectrum figure of the titanyl phthalocyanine synthesize | combined by the synthesis example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Electrophotographic photoreceptor 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 ... Charging means 1B ... Pre-cleaning exposure means 1C ... Drive means 1D ... First transfer means 1E ... Second transfer means 1F ... Intermediate transfer member 1G: image receiving medium carrier 21 ... conductive support 22 ... photosensitive layer 23 ... undercoat layer

Claims (10)

A photosensitive member, a charging device that uniformly charges the surface of the photosensitive member, an image exposure unit that performs image exposure after uniform charging to form an electrostatic latent image, and a developing unit that develops the electrostatic latent image. An electrophotographic apparatus having a transfer means for transferring a developed image and operated at a time from a charging portion to a developing portion of 300 msec or less, the photosensitive member comprising at least a photosensitive layer on a conductive support. The titanyl phthalocyanine in which the photosensitive layer has a maximum diffraction peak at least 27.2 ° as a diffraction peak (± 0.2 °) with respect to a characteristic X-ray (wavelength 1.542 mm) of CuKα as a charge generation material An electrophotographic apparatus comprising a single layer containing an electron transport material represented by the following general formula (1) as a charge transport material.

In the formula, R1 and R2 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, R3, R4, R5, R6, R7, R8, R9, 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 cycloalkyl group Represents a group selected from the group consisting of a substituted or unsubstituted aralkyl group. A photosensitive member, a charging device that uniformly charges the surface of the photosensitive member, an image exposure unit that performs image exposure after uniform charging to form an electrostatic latent image, and a developing unit that develops the electrostatic latent image. An electrophotographic apparatus having a transfer means for transferring a developed image and operated at a time from a charging portion to a developing portion of 300 msec or less, the photosensitive member comprising at least a photosensitive layer on a conductive support. The titanyl phthalocyanine in which the photosensitive layer has a maximum diffraction peak at least 27.2 ° as a diffraction peak (± 0.2 °) with respect to a characteristic X-ray (wavelength 1.542 mm) of CuKα as a charge generation material An electrophotographic apparatus comprising a single layer containing an electron transport material represented by the following general formula (2) as a charge transport material.

In the formula, R 1 and R 2 each independently represent a group selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, and a substituted or unsubstituted aralkyl group. The titanyl phthalocyanine has a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray of CuKα (wavelength 1.542 mm), and further 9.4 °, It has major peaks at 9.6 ° and 24.0 °, and has a peak at 7.3 ° as the lowest angle diffraction peak. It has a peak at 7.3 ° and a peak at 9.4 °. The electrophotographic apparatus according to claim 1, wherein there is no peak between them. The electrophotographic apparatus according to claim 3, wherein an average particle diameter of the titanyl phthalocyanine is 0.25 μm or less. 5. The electrophotographic apparatus according to claim 1, wherein the charge transport material contained in the photosensitive layer contains both a hole transport material and an electron transport material. The electrophotographic apparatus according to claim 1, wherein the hole transport material is represented by the following structural formula (1).

The electrophotographic apparatus according to claim 1, wherein the charging process is performed with positive charging. 2. The electrophotographic apparatus comprises a plurality of electrophotographic photosensitive members, and forms a color image by sequentially superimposing monochromatic toner images developed on the respective electrophotographic photosensitive members. The electrophotographic apparatus according to any one of items 7 to 7. The electrophotographic apparatus includes an intermediate transfer unit that primarily transfers a toner image developed on an electrophotographic photosensitive member onto an intermediate transfer member and then secondary-transfers the toner image on the intermediate transfer member onto a recording material. 2. The electrophotographic apparatus according to claim 1, wherein a color image is formed by sequentially superimposing a plurality of color toner images on an intermediate transfer member, and the color image is secondarily transferred collectively onto a recording material. The electrophotographic apparatus according to any one of 1 to 8. 10. The removable process cartridge according to claim 1, wherein the image forming element is a detachable process cartridge integrally supporting at least a photosensitive member and one unit selected from a charging unit, a developing unit, and a cleaning unit. An electrophotographic apparatus according to claim 1.

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