JP4397328B2 - Electrophotographic photosensitive member, image forming apparatus using the same, and process cartridge - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member, an electrophotographic image forming apparatus such as a copying machine, a printer, and a facsimile, and a process cartridge for the image forming apparatus. More specifically, without using the Carlson process, an electrophotographic photosensitive member that forms an electrostatic latent image by exposure and voltage application to the surface of the photosensitive member, a copying machine, a printer, a facsimile machine, etc. using the photosensitive member. The present invention relates to an image forming apparatus and a process cartridge.

Conventionally, an electrophotographic image forming method using the Carlson process generally used is as follows.
1) First, the surface of the photoreceptor is uniformly charged.
2) The electrostatic charge near the surface of the photoreceptor is erased by image exposure, and an electrostatic charge latent image is formed on the surface of the photoreceptor.
3) The electrostatic latent image is developed with charged colored fine particles called toner to form a toner image on the surface of the photoreceptor.
4) The toner image is transferred onto the transfer member directly or via an intermediate transfer member.
5) The toner image is fixed on the transfer member by a method such as heating.
6) To form the next image, the toner remaining on the surface of the photoreceptor after the image formation is removed by a cleaning unit.
7) In order to form the next image, the static charge remaining on the photoconductor after the image formation is neutralized by the neutralizing means.

As described above, in order to form an electrostatic charge latent image, first, it is necessary to uniformly charge the surface of the photoreceptor, and a charging method using corona discharge is generally used for the charging. .
As a charging method using corona discharge, charging is performed by applying a high voltage to a metal wire, a charging roller whose resistance value is controlled within a certain range is brought into contact with or close to the surface of the photoconductor, and a high voltage is applied. A method of charging the photoreceptor is used.

However, when the photoconductor is charged using corona discharge, substances having a strong oxidizing action such as ozone and nitrogen oxides and corona products such as NH ₄ NO ₃ are generated. Such ozone and nitrogen oxides cause deterioration of the photoreceptor composition (constituent material of the photoreceptor), leading to leakage of surface charges on the photoreceptor and an increase in residual charge inside the photoreceptor, and image density based on it. Causes deterioration and dirt on the background.
In addition, the mechanical strength of the surface of the photosensitive layer is lowered, the wear amount of the photosensitive layer is increased, and the life of the photoreceptor is reduced. In addition, when a hygroscopic substance such as NH ₄ NO ₃ adheres to the surface of the photoreceptor, the surface resistance of the photoreceptor decreases particularly in a high-humidity environment, and the electrostatic charge latent image on the surface of the photoreceptor is disturbed, causing image blur and image flow. Occurs, reducing the life of the photoreceptor.
As described above, the charging using corona discharge significantly reduces the quality of the image to be formed, requires various measures to maintain the durability and stability of the image forming system, and increases the cost of image formation. have.

In recent years, an image forming apparatus using an electrophotographic method has been applied to computer output recording and digital printing, and higher-definition image formation is desired. In the conventional electrophotographic method, in order to form an electrostatic charge latent image, image exposure is performed on the photoreceptor after uniform charging to generate charges inside the photoreceptor. The charge generated by this light moves through the photosensitive layer along the electric field formed by the uniformly charged charge on the photoconductor, erasing the charge on the front and back surfaces of the photoconductor, and the desired latent electrostatic latent image. Form.
The charge generated by light inside the photosensitive layer diffuses in the direction perpendicular to the electric field direction while moving inside the photosensitive layer, and as a result, the charge in the area wider than the exposed light image is erased, There is a drawback that the resolution and sharpness of the electrostatic latent image are lowered. The diffusion of the charges generated by this light becomes more severe as the photosensitive layer becomes thicker.

On the other hand, the electrophotographic photoreceptor used in the conventional image forming method using the Carlson method is designed to have a thick photosensitive layer from the viewpoint of high sensitivity and high durability. It has a drawback that the resolution is lowered.
Further, in the conventional electrophotographic method, it is necessary to uniformly charge the entire surface of the photoreceptor.
Generally, an electric pinhole in which a charged charge leaks locally when a high electric field is applied exists in the photosensitive layer of the photoreceptor. For this reason, when high charging is performed and a local leak occurs, there is a defect that a black spot (dirt background) or white spot (color loss) -like defect occurs on the image. .

Particularly in recent years, in an electrophotographic printer, a toner charged with the same polarity as the charged charge on the surface of the photoconductor is used for a portion of the photoconductor surface that has been exposed to writing light such as a laser and has a low surface potential. A reversal development method in which toner is attached is often used. In this case, the background portion that occupies most of the photoconductor is highly charged, and when the above-described charge leakage occurs, toner adheres to the background portion, resulting in background contamination.
In order to eliminate the disadvantages of the conventional image forming method, the electrostatic charge latent image is formed by charging only the image exposure portion of the photosensitive member surface without charging the entire photosensitive member surface by corona discharge. A method of forming is desired.

Conventionally, the following method has been disclosed as a method for directly forming an electrostatic charge latent image on an image exposure portion on the surface of the photosensitive member without uniformly charging the entire surface of the photosensitive member. That is, a photo image is irradiated on a photosensitive member provided with a layer containing a substance that expresses a photovoltaic force such as zinc oxide or titanium oxide on a conductive support, and the photo-generated light is generated in a portion irradiated with light. There is a method in which an electrostatic charge latent image is formed using a voltage and development is performed (for example, see Non-Patent Document 1).
However, in this method, the photovoltage is about 300 to 500 mV, and when developed using a developer used in normal electrophotography, the image density is low and the time required for development is long. There are difficulties in performing high-speed printing. For this purpose, development of a development system capable of developing at a high speed with a voltage of about several hundred mV is necessary, but no development method capable of developing such a low-potential electrostatic latent image has been developed.

In addition, a photosensitive member having a thin-film power generation layer in which p-type, n-type, and i-type amorphous silicone films are laminated in a multilayer on a light-transmitting support, and an electromotive force of about 18v is expressed by light irradiation. Is disclosed (for example, see Patent Document 1).
The method using the thin-film power generation layer in which the amorphous silicone films are laminated in multiple layers has a higher potential and is more advantageous for development than the above-described photovoltaic method using zinc oxide or titanium oxide. However, the silicone film has to be laminated in multiple layers, and there is a disadvantage that the manufacturing cost of the photoreceptor increases.
Further, exposure is performed while applying a voltage to the photosensitive layer of the photosensitive member, and positive and negative charges generated by light in the photosensitive layer are polarized inside the photosensitive layer by an external electric field to develop a potential to develop an electrostatic latent potential. A method of forming an image (internal polarization type charging method) is also known (see, for example, Patent Document 2 or Patent Document 3).

However, in these internal polarization type charging methods, a voltage of several tens of volts to several hundreds of volts or more can be instantly expressed. However, when the external voltage is removed, positive and negative charges themselves separated by the external voltage are used. Stable electrostatic latent image because both charges are attracted to each other by the self electric field that is formed, and the potential is reduced or the formed latent image is disturbed due to diffusion of recombined or separated charges. Is difficult to form.
In addition, in this method, there is a process restriction in which the time from the charging step to the development step must be shortened in order to prevent the recombination and diffusion of the charges. In addition, a charge having a polarity opposite to the applied voltage is induced on the surface of the photosensitive member, and charge leakage to an external voltage applying member, a conductive support of the photosensitive member, a conductive undercoat layer, etc. is likely to occur. The charge latent image lacks stability.
Also, a laminated photoreceptor having a first charge generation layer that generates charges by light irradiation at the time of charging and a second charge generation layer that generates charges by light irradiation at the time of image exposure on the surface of the photoreceptor. Using negative voltage, the positive and negative charges generated by light in the photosensitive layer are polarized inside the photosensitive layer by an external voltage while applying a positive voltage to the surface of the photoreceptor so that negative charging is possible. Then, a method of forming an electrostatic latent image by performing image exposure is known (for example, see Patent Document 4).

However, this method also uses the same internal polarization charging method as in Patent Document 2 or Patent Document 3, and has the same drawbacks as described above.
As another method, the latent image carrier is charged by irradiating the electrostatic latent image carrier having photoconductivity with light and bringing a voltage applying member into contact with the portion where the electrical resistance of the photoconductive portion is lowered. A method and an apparatus for forming an image by performing exposure for forming an electrostatic latent image after charging to form an electrostatic charge latent image on the electrostatic latent image carrier are disclosed (for example, Patent Documents). 5).
However, this method eliminates the disadvantages due to charging using corona discharge, but the latent image formation uses a conventional electrophotographic method in which image exposure is performed after uniform charging on the surface of the photosensitive member. I can not escape the shortcomings.

JP 7-168384 A JP-A-8-76559 JP-A-9-26681 JP 2001-183853 A JP 2001-147576 A Edited by Eiichi Inoue, Photographic Engineering IV, P280

The object of the present invention is to overcome the above-mentioned drawbacks of the conventional charging method (deterioration of the constituent material of the photoreceptor due to the generation of oxidizing gas in the discharge-type charging system, generation of abnormal images such as image blur in the charge-injection charging system, and It is to solve the deterioration of the imaging member). Specifically, the occurrence of abnormal images can be suppressed by suppressing the generation of ozone, nitrogen oxides, etc. during charging, and the deterioration of the image forming member around the photoreceptor can be suppressed, so that repeated use can be performed. An object of the present invention is to provide an electrophotographic photosensitive member capable of forming a good image and forming an electrostatic latent image and an image forming apparatus which are compact, energy-saving and excellent in environmental friendliness.
Another object of the present invention is to provide an image forming apparatus using the photoconductor, which has high durability and high reliability that does not generate an abnormal image even in repeated use, and is an energy saving electrostatic latent image forming apparatus. Another object is to provide an image forming apparatus. Another object of the present invention is to provide a process cartridge using the photoconductor that is easy to handle and can be designed compactly.

As a result of intensive studies on a method of forming an electrostatic charge latent image on an electrophotographic photosensitive member without using a corona discharge charging step that eliminates the conventional drawbacks, the present inventors have determined that at least a photosensitive layer on a conductive support. A conductive voltage applying member is brought into contact with a photosensitive member provided with a surface containing a substance capable of generating charge upon exposure (hereinafter referred to as “photocharged charge layer”) at the same time as image exposure or image exposure. It was found that the exposed portion can be charged higher than the non-exposed portion by applying a voltage to the photoreceptor later through a voltage application member, and an electrostatic charge latent image can be formed on the photoreceptor.
These photocharging phenomena are caused by a phenomenon different from the conventionally known internal polarization type charging in which a potential having the same polarity as the applied voltage is expressed and charging with a polarity opposite to the applied voltage is performed. This is considered to be because the charge having the same polarity as the applied voltage was charged in the photocharged charge layer (hereinafter referred to as “photocharge charge”). In addition, since the electrostatic charge latent image forming method by photocharge charging generates almost no ozone or NOx gas, it is possible to suppress deterioration of the photoconductor due to the conventional discharge-type charging, and to be a compact image forming apparatus with less environmental pollution. It was found that it is possible to provide.
Furthermore, residual charges on the photosensitive member can be removed by exposure of the photosensitive region of the photosensitive layer, and a simple and energy-saving static elimination means is possible.
The present inventors have completed the present invention based on the above findings.

That is, the said subject is solved by (1)-( 25 ) of this invention.
(1) “At least a step of performing image exposure on the photoconductor and at the same time as or after the image exposure, a voltage is applied to the photoconductor through a conductive voltage applying member in contact with the photoconductor to sensitize the photoconductor. An electrophotographic photosensitive member for use in an image forming method including a step of forming an electrostatic latent image having the same polarity as an applied voltage on a body, wherein the electrophotographic photosensitive member is at least a photosensitive layer and at least the image exposed on a conductive support A charge generation material that generates charge and a photocharge charge layer containing a charge transport material , and the photocharge charge layer is disposed on the surface of the photoreceptor, and the charge generation material contained in the photosensitive layer is light An electrophotographic photosensitive member having a maximum absorption wavelength different from that of the charge generation material contained in the charge charging layer ;
(2) “The electrophotographic photosensitive member according to (1) above, wherein the charge generation material contained in the photocharged charge layer is an organic pigment”;
(3) “ Maximum absorption wavelength of the organic pigment used in the photocharge charging layer, wherein the charge generating material contained in the photosensitive layer is an organic pigment different from the organic pigment contained in the photocharged charge layer” And the maximum absorption wavelength of the organic pigment used in the photosensitive layer is 200 nm or more apart from the electrophotographic photoreceptor according to (2) above;
( 4 ) "The electrophotographic photosensitive member according to (2) or (3) above, wherein the organic pigment contained in the photocharged charge layer is an azo pigment";
( 5 ) The electrophotographic photosensitive member according to ( 4 ), wherein the azo pigment is an azo pigment represented by the following general formula (I).

［式中、Ｃｐ_１、Ｃｐ_２はカップラー残基を表わす。Ｒ_２０１、Ｒ_２０２はそれぞれ、水素原子、ハロゲン原子、アルキル基、アルコキシ基、シアノ基のいずれかを表わし、同一でも異なっていてもよい。また該Ｃｐ_１、Ｃｐ_２は下記一般式（II）

[Wherein, Cp ₁ and Cp ₂ represent coupler residues. R ₂₀₁ and R ₂₀₂ each represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or a cyano group, and may be the same or different. The Cp ₁ and Cp ₂ are represented by the following general formula (II)

（式中、Ｒ_２０３は、水素原子、アルキル基、アリール基を表わす。Ｒ_２０４、Ｒ_２０５、Ｒ_２０６、Ｒ_２０７、Ｒ_２０８はそれぞれ、水素原子、ニトロ基、シアノ基、ハロゲン原子、トリフルオロメチル基、アルキル基、アルコキシ基、ジアルキルアミノ基、水酸基を表わし、同一でも異なっていてもよい。Ｚは置換もしくは無置換の芳香族炭素環または置換もしくは無置換の芳香族複素環を構成するのに必要な原子群を表わす。）で表わされる基である。］」；
（６）「前記アゾ顔料のＣｐ_１とＣｐ_２とが互いに異なるものであることを特徴とする前記（５）に記載の電子写真感光体」；
（７）「前記光電荷充電層に含有される有機顔料がチタニルフタロシアニンであることを特徴とする前記（２）または（３）に記載の電子写真感光体」；
（８）「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するチタニルフタロシアニンであることを特徴とする前記（７）に記載の電子写真感光体」；
（９）「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、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、かつ前記７．３°のピークと９．４°のピークの間にはピークを有さず、かつ２６．３°にピークを有さないことを特徴とする前記（８）に記載の電子写真感光体」；
（１０）「前記電荷輸送物質が正孔輸送物質であることを特徴とする前記（１）〜（９）の何れかに記載の電子写真感光体」；
（１１）「前記正孔輸送物質が、少なくともトリアリールアミン構造を有する化合物であることを特徴とする前記（１０）に記載の電子写真感光体」；
（１２）「前記電荷輸送性物質が高分子電荷輸送性物質であることを特徴とする前記（１）〜（９）の何れかに記載の電子写真感光体」；
（１３）「前記高分子電荷輸送性物質が正孔輸送物質であることを特徴とする前記（１２）に記載の電子写真感光体」；
（１４）「前記高分子電荷輸送性物質が架橋構造を有することを特徴とする前記（１２）に記載の電子写真感光体」；
（１５）「前記光電荷充電層中にフィラーが含有されることを特徴とする前記（１）〜（１４）の何れかに記載の電子写真感光体」；
（１６）「前記感光層が少なくとも電荷発生層と電荷輸送層とからなることを特徴とする前記（１）〜（１５）の何れかに記載の電子写真感光体」；
（１７）「前記導電性支持体がエンドレスベルト形状であることを特徴とする前記（１）〜（１６）の何れかに記載の電子写真感光体」；
（１８）「少なくとも、感光体と該感光体に像露光を行なう像露光手段、該像露光と同時または像露光後に該感光体と接触している導電性電圧印加部材を介して該感光体に電圧を印加して該感光体表面に印加電圧と同極性の静電荷潜像を形成するための電圧印加手段を有する画像形成装置において、該感光体が前記（１）〜（１７）の何れか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」；
（１９）「少なくとも、感光体と該感光体に像露光を行なう像露光手段、該像露光と同時または像露光後に該感光体と接触している導電性電圧印加部材を介して該感光体に電圧を印加して該感光体表面に印加電圧と同極性の静電潜像を形成するための電圧印加手段、及び感光体上の静電荷を除去するための除電用露光手段を有する画像形成装置において、該感光体が前記（１）〜（１７）の何れか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」；
（２０）「前記像露光手段として４００ｎｍ以上の波長の光源を用いることを特徴とする前記（１８）または（１９）に記載の画像形成装置」；
（２１）「前記像露光手段に用いられる光を光電荷充電層が８０％以上吸収することを特徴とする前記（２０）に記載の画像形成装置」；
（２２）「前記像露光手段に用いられる光の波長が、感光層に用いられる電荷発生物質への吸収のない領域の光であることを特徴とする前記（１８）〜（２１）の何れかに記載の画像形成装置」；
（２３）「前記感光体上の静電荷を除去するための除電用露光手段による除電光が、光電荷充電層を３０％以上透過することを特徴とする前記（１８）〜（２２）の何れかに記載の画像形成装置」；
（２４）「前記感光体の光電荷充電層が正極性電荷の輸送機能を有しており、電圧印加部材に負極性電圧が印加されることを特徴とする前記（１８）〜（２３）の何れかに記載の画像形成装置」；
（２５）「感光体と、像の露光手段、電圧印加手段、現像手段、クリーニング手段、除電手段及び転写手段から選ばれる少なくとも１つとを一体化し、画像形成装置本体に着脱自在に設けたプロセスカートリッジであって、該感光体が前記（１）〜（１７）の何れかに記載の電子写真感光体であることを特徴とするプロセスカートリッジ」。

(In the formula, R ₂₀₃ represents a hydrogen atom, an alkyl group, or an aryl group. R ₂₀₄ , R ₂₀₅ , R ₂₀₆ , R ₂₀₇ , and R ₂₀₈ are a hydrogen atom, a nitro group, a cyano group, a halogen atom, and trifluoro, respectively. M represents a methyl group, an alkyl group, an alkoxy group, a dialkylamino group, or a hydroxyl group, which may be the same or different, and Z constitutes a substituted or unsubstituted aromatic carbocyclic ring or a substituted or unsubstituted aromatic heterocyclic ring. Represents a group of atoms necessary for. ] ”;
( 6 ) "The electrophotographic photosensitive member according to ( 5 ) above, wherein Cp ₁ and Cp ₂ of the azo pigment are different from each other";
( 7 ) "The electrophotographic photosensitive member according to (2) or (3) above, wherein the organic pigment contained in the photocharged charge layer is titanyl phthalocyanine";
( 8 ) “The titanyl phthalocyanine is 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 波長) of CuKα. The electrophotographic photosensitive member according to ( 7 ) above, which is characterized by:
( 9 ) “The titanyl phthalocyanine has a diffraction peak (± 0.2 °) of Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542Å) of CuKα, and further 9.4 °, 9.6 °, 24.0. It has a main peak at ° and a peak at 7.3 ° as the lowest diffraction peak, and there is a peak between the 7.3 ° peak and the 9.4 ° peak. And the electrophotographic photosensitive member according to ( 8 ) above, which does not have a peak at 26.3 °;
(10) "The electrophotographic photosensitive member according to any one of (1) to (9) above, wherein the charge transport material is a hole transport material";
(11) "The electrophotographic photosensitive member according to (10) above, wherein the hole transport material is a compound having at least a triarylamine structure";
(12) "The electrophotographic photosensitive member according to any one of (1) to (9) above, wherein the charge transporting substance is a polymer charge transporting substance";
(13) "The electrophotographic photosensitive member according to (12) above, wherein the polymer charge transporting substance is a hole transporting substance";
(14) "The electrophotographic photosensitive member according to (12) above, wherein the polymer charge transporting substance has a crosslinked structure";
( 15 ) "The electrophotographic photosensitive member according to any one of (1) to ( 14 ) above, wherein a filler is contained in the photocharged charge layer";
( 16 ) "The electrophotographic photosensitive member according to any one of (1) to ( 15 ) above, wherein the photosensitive layer comprises at least a charge generation layer and a charge transport layer";
( 17 ) "The electrophotographic photosensitive member according to any one of (1) to ( 16 ) above, wherein the conductive support has an endless belt shape";
( 18 ) “At least the photosensitive member and image exposing means for performing image exposure on the photosensitive member, and the photosensitive member via the conductive voltage applying member that is in contact with the photosensitive member simultaneously with or after the image exposure. In the image forming apparatus having a voltage applying unit for applying a voltage to form an electrostatic charge latent image having the same polarity as the applied voltage on the surface of the photoconductor, the photoconductor is any one of (1) to ( 17 ). An image forming apparatus characterized in that it is an electrophotographic photosensitive member according to claim 1;
( 19 ) “At least the photoconductor and image exposure means for performing image exposure on the photoconductor, and at the same time through the conductive voltage application member in contact with the photoconductor at the same time as or after the image exposure. An image forming apparatus having a voltage applying means for applying a voltage to form an electrostatic latent image having the same polarity as the applied voltage on the surface of the photoreceptor, and an exposure means for removing static electricity on the photoreceptor Wherein the photoconductor is the electrophotographic photoconductor according to any one of (1) to ( 17 ) above;
( 20 ) "The image forming apparatus according to ( 18 ) or ( 19 ) above, wherein a light source having a wavelength of 400 nm or more is used as the image exposure unit";
( 21 ) "The image forming apparatus according to ( 20 ), wherein the photocharged layer absorbs 80% or more of the light used in the image exposure unit";
( 22 ) Any one of the above ( 18 ) to ( 21 ), wherein the wavelength of light used in the image exposure means is light in a region that is not absorbed by the charge generating material used in the photosensitive layer An image forming apparatus according to claim 1;
( 23 ) Any one of the above ( 18 ) to ( 22 ), wherein the neutralizing light by the neutralizing exposure means for removing the electrostatic charge on the photosensitive member is transmitted through the photocharged charge layer by 30% or more. An image forming apparatus according to claim 1;
( 24 ) “The photocharged charge layer of the photoconductor has a positive charge transport function, and a negative voltage is applied to the voltage application member,” ( 18 ) to ( 23 ), Any of the image forming apparatuses described above;
( 25 ) "Process cartridge in which a photosensitive member and at least one selected from an image exposing unit, a voltage applying unit, a developing unit, a cleaning unit, a neutralizing unit, and a transfer unit are integrated and detachably provided on the main body of the image forming apparatus A process cartridge, wherein the photoconductor is the electrophotographic photoconductor according to any one of (1) to ( 17 ).

The effects of the present invention are as follows.
The inventions (1) to ( 25 ) are referred to as the present inventions (1) to ( 25 ).
The present invention (1): having a photocharge charge layer containing at least a photosensitive layer and a charge generation material that generates charges upon image exposure or a charge generation material and a charge transport material on a conductive support, and the photo charge charge layer On the surface of the photoconductor, a voltage is applied to the photoconductor through a conductive voltage applying member in contact with the photoconductor at the same time as image exposure or after image exposure. It is possible to provide a photoconductor that charges the charge layer with the same polarity as the applied voltage and can form an electrostatic charge latent image without corona discharge, which is a cause of deterioration of the photoconductor, and to the environment. A gentle electrostatic latent image forming method and an image forming apparatus can be provided.
In addition, since the photosensitive layer is provided, it is possible to provide a photoconductor capable of removing an electrostatic charge on the surface of the photoconductor with energy saving by light.

  Invention (2): Since the charge generating material contained in the photocharged charge layer is an organic pigment, visible light can be used as an image exposure light source for forming an electrostatic latent image. Therefore, it is possible to prevent the photoconductor from being deteriorated, and to provide a photoconductor having a long life. In addition, the absorption spectrum has a wide variety compared to inorganic pigments, and the design of the photoreceptor becomes easy.

The present invention (3): the maximum absorption peak of the charge generation material contained in the photocharge charging layer and the photosensitive layer (charge generation layer) is separated by 200 nm or more, so that the absorption regions do not overlap each other and the photocharge is efficient. It is possible to form an electrostatic charge latent image by charging and to remove static electricity from the residual electrostatic charge. Since the organic pigment contained in the photocharge charging layer is an azo pigment, a photoconductor with high photocharge efficiency can be provided.
Present invention ( 4 ): The organic pigment contained in the photocharge charging layer is an azo pigment, whereby a photoconductor with high photocharge charge efficiency can be provided.
Present invention ( 5 ): In particular, the azo pigment represented by the general formula (I) has a high charge generation capability, is resistant to light fatigue in repeated use, and can provide a photoconductor with high photocharge charging efficiency.
Present invention ( 6 ): Among the azo pigments represented by the general formula (I), asymmetric pigments having different two coupler components provide a photoconductor having extremely high photocarrier generation ability and high photocharge charging efficiency. it can.

Present invention ( 7 ): The organic pigment contained in the photocharge charging layer is titanyl phthalocyanine, whereby a photoconductor having high photocharge charging efficiency can be provided.
Present invention ( 8 ): By being titanyl phthalocyanine of a specific crystal (having a maximum diffraction peak at 27.2 degrees), a photoconductor with higher photocharge charging efficiency can be provided.
Present invention ( 9 ): Particularly, a titanyl phthalocyanine having a specific crystal can provide a photoconductor with higher photocharge charging efficiency.
Present invention (10): The charge transport material contained in the photocharge charge layer is a hole transport material, whereby a photoconductor with high photocharge charge efficiency of negative charge can be provided.
Invention (11): The formation of an electrostatic latent image by high-speed photocharge charging is possible because the hole transport material contained in the photocharge charge layer is at least one compound having a triarylamine structure. become.

Invention (12): By using a polymer charge transporting material as a charge transporting material in the photocharge charging layer, wear and scratches on the surface of the photoreceptor are reduced, and the electrostatic charge latent image by uniform photocharge charging is stabilized. Thus, it is possible to provide a highly durable photoreceptor.
Invention (13): Since the polymer charge transporting material contained in the photocharge charging layer is a hole transporting material, the photocharge charging efficiency of the negative charge is high, and the photoconductor surface is worn or scratched. Thus, it is possible to provide a highly durable photoconductor that can stably obtain an electrostatic charge latent image by uniform photocharge charging.
Invention (14): The photocharge charging layer contains a polymer charge transporting substance having a crosslinked structure, whereby the photocharge charge layer has higher hardness and less photoconductor surface wear and scratches. It is possible to provide a highly durable photoconductor that can stably obtain an electrostatic latent image by uniform photocharge charging.

Present invention ( 15 ): By containing a filler in the photocharged charge layer, the surface of the photoconductor is less worn, and a long-life photoconductor in which formation of an electrostatic latent image is stable can be provided.
The present invention ( 16 ): a photosensitive layer having at least a charge generation layer and a charge transport layer, so that a photosensitive layer having high photosensitivity and photoresponsiveness can be designed, and a photoconductor capable of photostatic discharge with high photostatic efficiency and energy saving. Can provide.
Present invention ( 17 ): Since the photosensitive member has a flexible endless belt shape, it enables wide contact between the voltage applying means and the photosensitive member, and formation of an electrostatic charge latent image by uniform and stable photocharge charging is possible. The development nip between the photoconductor surface and the developing member, the transfer nip between the photoconductor and the transfer member, etc. are secured stably, and reliability that does not cause abnormal images such as image flow, image blurring, roughness, streaks It is possible to provide a photoconductor capable of designing an image forming apparatus having a high level.

Present invention ( 18 ): An energy-saving image forming apparatus capable of forming a highly reliable image free from abnormal images such as image flow, image blurring, roughness, streaks, and the like, and free of discharge products. Can be provided.
Invention ( 19 ): An energy-saving image forming apparatus can be provided by using light neutralization.

Invention ( 20 ): By using a light source having a wavelength of 400 nm or more without using ultraviolet rays as the image exposure means, it is possible to provide a highly reliable image forming apparatus with little deterioration of the photoreceptor.
The present invention (21), (22): By the image exposure of the electrostatic latent image formed does not absorb the charge generation layer, a is an image forming equipment forming the electrostatic latent image by good optical charge storage efficiency Can be provided.
Invention ( 23 ): An image forming apparatus in which the charge removal efficiency is not lowered can be provided by preventing the light charge removal layer from absorbing the light charge removal light.
The present invention ( 24 ): The photocharge charging layer of the photoconductor has a positive charge transport function, and a negative voltage is applied to the voltage applying means, whereby the electrostatic charge forming efficiency by photocharge charging is high and reliable. A highly energy-saving image forming apparatus can be provided.
The present invention ( 25 ): It is possible to provide a highly reliable process cartridge in which abnormal images such as image flow, image blurring, roughness, and streak-like background stains do not occur.

As shown in FIG. 1, the basic layer structure of the electrophotographic photoreceptor of the present invention (hereinafter also referred to simply as the photoreceptor) is at least a charge generating material and charge transport on a conductive support (11). It comprises a photosensitive layer (12) containing a substance and a photocharged charge layer (13) containing at least a charge generating substance laminated thereon.
The charging mechanism for the photosensitive member provided with the photocharge charging layer of the present invention is based on a novel method, and the detailed mechanism is not clear at present, but the present inventors have developed a latent image by photocharge charging. The formation mechanism is considered to be as shown below.

The mechanism will be described with reference to FIG.
[1] When a desired image exposure is performed on a photoconductor provided with a photocharged charge layer containing a charge generating material that generates charge upon exposure on the surface of the photoconductor using light absorbed by the photocharged charge layer, Both positive and negative charges are generated at the exposed portion of the photocharged charge layer (FIG. 2A).
[2] When a voltage is applied to a voltage application member (hereinafter sometimes referred to as a “charging member”) that is in contact with the surface of the photoreceptor before the charge is recombined and disappears, a charge having a polarity opposite to the applied voltage Moves to the voltage applying member, and the photocharge charging layer is charged with the same polarity as the voltage applying member. (FIG. 2 (b)).
[3] A charge having the opposite polarity to the applied voltage is induced on the conductive support side of the photoreceptor, and a potential having the same polarity as the applied voltage is developed in the exposed portion of the photoreceptor (FIG. 2C).
On the other hand, in the non-exposed portion, when there is a charge generated by thermal excitation or the like in the dark place in the photocharge layer, a slight charge is performed by voltage application, but the potential is lower than that of the exposed portion.
[5] As described above, an electrostatic latent image having the same polarity as the applied voltage is formed on the photoconductor in accordance with image exposure.
[6] At this time, the photosensitive layer between the photocharge charging layer and the conductive support has a role of amplifying the potential to be developed, and the smaller the capacitance, the higher the potential is developed.
[7] The charge charged in the photocharge charging layer in this manner is trapped in the photocharge charge layer or at the interface between the photocharge charge layer and the photosensitive layer and is not easily combined with the charge on the support side. Thus, a more stable electrostatic latent image is formed as compared with the electrostatic latent image formed by the internal polarization type charging method.
[8] Since the electrostatic charge is charged in the thin photocharged charge layer on the surface of the photoreceptor, the electrostatic charge latent image formed with less charge diffusion becomes sharp with high resolving power.
[9] The electrostatic charge latent image in the present invention is formed by internal charges formed in the photocharge charging layer. For this purpose, a charge generating material that absorbs light and generates charges in the photocharge charging layer. Must be contained.

Next, the layer structure of the photoreceptor in the present invention will be described.
<Photocharge charge layer>
As the charge generation material used for the photocharged charge layer (13) of the present invention, conventionally known materials can be used as charge generation materials for electrophotography. Among these, organic materials can be used effectively. This is because the absorption wavelength of organic materials can be controlled arbitrarily depending on the chemical structure. As described later, image exposure for forming an electrostatic latent image and static elimination exposure for neutralizing residual charges on the surface of the photoreceptor are performed. In either case, the charge generation material used in the photocharge charge layer is different from the absorption wavelength region of the charge generation material in the photosensitive layer (charge generation layer), which is the lower layer of the photocharge charge layer. Advantages such as efficient generation of optical carriers can be produced. For this reason, compared with an inorganic material, an organic material can be effectively used for this invention.

  Examples of such organic materials include phthalocyanine pigments such as various metal phthalocyanines and metal-free phthalocyanines, azulenium salt pigments, squaric acid methine pigments, azo pigments having a carbazole skeleton, azo pigments having a triphenylamine skeleton, diphenylamine Azo pigments having a skeleton, azo pigments having a dibenzothiophene skeleton, azo pigments having a fluorenone skeleton, azo pigments having an oxadiazole skeleton, azo pigments having a bis-stilbene skeleton, azo pigments having a distyryloxadiazole skeleton, di Azo pigments having a styrylcarbazole skeleton, perylene pigments, anthraquinone or polycyclic quinone pigments, quinone imine pigments, diphenylmethane and triphenylmethane pigments, benzoquinone and naphthoquinone pigments, shear Emissions and azomethine pigments, indigoid pigments, and bisbenzimidazole pigments.

These charge generation materials can be used alone or as a mixture of two or more. In particular, the azo pigment represented by the general formula (I) and the specific crystal form (at least 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) Since titanyl phthalocyanine (having a maximum diffraction peak at 27.2 °) has high sensitivity and high durability and is particularly resistant to light fatigue, it can be effectively used as a charge generating material of the present invention. Among them, those having different Cp ₁ and Cp _{2 in the} general formula (I) exhibit particularly high sensitivity among the materials represented by the general formula (I), and are very good as the charge generating material of the photoreceptor of the present invention. Used for. Among the titanyl phthalocyanines having the maximum diffraction peak at 27.2 °, there are further main peaks at 9.4 °, 9.6 °, and 24.0 °, and the diffraction peak at the lowest angle is 7%. A titanyl phthalocyanine crystal having a peak at .3 °, no peak between the peak at 7.3 ° and the peak at 9.4 °, and no peak at 26.3 ° is particularly sensitive. Moreover, the decrease in chargeability in repeated use of the photoreceptor is small, and can be used very well as a charge generating material of the photoreceptor of the present invention.

  When the charge generation material used in the photocharge charging layer absorbs exposure for photostatic charge, the amount of light reaching the photosensitive layer (charge generation layer) described later decreases accordingly. As a result, the photosensitivity of the photosensitive member is lowered, the light neutralization efficiency is lowered, and it becomes difficult to stably form a clear image. For this reason, it is preferable that the charge generating material used in the photocharge charging layer sufficiently absorbs light in the wavelength region of image exposure for forming an electrostatic latent image. For this purpose, it is preferable that the charge generation material used for the photocharge charge layer is different from the charge generation material used for the photosensitive layer (charge generation layer) described later, and the absorption wavelength region is different.

In general, organic pigments preferably used as charge generating materials for photoreceptors are often highly molecular aggregates. Therefore, in general, the absorption spectrum is broad. Therefore, in order to make the absorption wavelength region of the charge generation material used for the photocharge charge layer different from the charge generation material used for the photosensitive layer (charge generation layer) described later, the absorption peak position is increased. It is necessary to shift. Specifically, in the range of 400 nm to 1200 nm, if the maximum absorption peak wavelengths of both charge generating materials are separated by 200 nm or more, the absorption regions of the two rarely overlap, and even if they overlap, the wavelength region is slight. .
Such an evaluation method of the absorption wavelength region of the charge generation material (organic pigment) can be performed as follows.

A sample is prepared by coating and drying a coating solution for a photocharge charging layer and a coating solution for a photosensitive layer (charge generation layer) used on the photoreceptor on an optically transparent support. Subsequently, each absorption spectrum is measured with a commercially available spectrophotometer, whereby the absorption profile and the maximum absorption wavelength of the charge generating material are determined. An example of such a measurement result is shown in FIG.
The absorption spectra of charge generation materials (denoted as CGM A, B, and C in the figure) are respectively shown. For example, charge generation material C is used as the charge generation material of the photosensitive layer. Here, when the charge generating substance A is used in the photocharge charging layer, the overlap of the absorption spectra of both is small, and if the charge eliminating exposure of approximately 700 nm or more is performed, the photocharge charge layer is hardly absorbed. On the other hand, when the charge generation material B is used for the photocharge charge layer, the overlap of the absorption spectra of both is very large, and not only the exposure wavelength for charge removal is very limited, Absorption may increase and the photosensitivity of the photoreceptor may be reduced. Thus, the distribution of the absorption spectrum of the charge generating material used in the photocharged charge layer and the photosensitive layer is important, and a good combination is obtained when the maximum absorption peak wavelengths of both are separated by 200 nm or more as shown in FIG. It becomes.

In order to provide a photocharge charging layer on the photosensitive layer, a ball mill, an attritor, an organic solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, butanone, and methyl ethyl ketone, together with a binder resin if necessary, may be used. It can be formed by dispersing in fine particles with a sand mill or the like and applying the solution after diluting the dispersion appropriately. The coating can be performed using a dip coating method, a spray coating method, a bead coating method, or the like.
The binder resin used as necessary for the photocharged charge layer includes polyamide, polyurethane, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polystyrene, poly-N-vinylcarbazole, polyacrylamide, vinyl chloride resin, A vinyl acetate resin, a vinyl acetate-vinyl chloride copolymer resin, or the like is used. These binder resins can be used alone or as a mixture of two or more.

  In addition, the present inventors have found that by adding a charge transport material together with the charge generation material to the photocharge charge layer, the efficiency of photocharge charge is increased and a higher charge potential can be expressed. . This is because a charge transport material is contained at the same time as the charge generation material, and a positive and negative charge pair that is relatively easily separated by light and electric field is generated near the contact interface between the charge generation material and the charge transport material. The charge having the opposite polarity to the applied voltage is transported to the charging member via the charge transport material or the charge generating material, moves to the charging member, and the charge having the same polarity as the applied voltage is charged to the photocharge charging layer. This is probably because of this.

  Examples of charge transport materials that can be added to the photocharged charge layer (13) include hole transport materials and electron transport materials. As described above, the photocharged charge layer of the present invention needs to cause the charge generated by image exposure to reach the surface of the photoreceptor (FIG. 2). At this time, the polarity opposite to the voltage applied to the charging member is required. Need to carry the charge. For this reason, a hole transport material is effectively used when negative polarity is applied to the charging member, and an electron transport material is effectively used when positive polarity is applied.

  Examples of the electron transporting material include chloroanil, bromanyl, 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 can be used alone or as a mixture of two or more.

Examples of the hole transport material include oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, 9- (p-diethylaminostyrylanthracene), 1,1-bis- (4-dibenzylaminophenyl) propane. , Styrylanthracene, styrylpyrazoline, phenylhydrazones, α-phenylstilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, thiophene derivatives, etc. can be used effectively. .
Among them, a compound having a triarylamine structure in a molecule has a high charge transporting ability and can cope with a high-speed process and can be used very effectively in the present invention. These hole transport materials can be used alone or as a mixture of two or more.

  In addition, you may contain these electron transport materials and hole transport materials simultaneously. The polarity to be charged on the photocharged charge layer (photoreceptor surface) should be determined to be negative or positive depending on the system design concept of the image forming apparatus to be used. However, most of the image forming apparatuses so far use an organic photoreceptor, and most of them employ a negatively charged photoreceptor. Also, in recent image forming apparatuses, digital writing / development is the mainstream, and the developing system used is combined with this. Further, hole transport materials occupy most of the charge transport materials used for the photoreceptor as materials capable of high-speed charge transfer. Under such circumstances, also in the present invention, the photosensitive layer, which is the lower layer of the photocharge charging layer, should make the best use of the known technology and should be applied to the image forming apparatus. Accordingly, the electrophotographic photosensitive member of the present invention is extremely advantageous in the negatively charged type, and therefore, a hole transport material is effectively used in the photocharged charge layer.

In addition, a polymer charge transport material having a function as a charge transport material and a function of a binder resin is also preferably used for the photocharge charge layer (13).
The photocharged charge layer (13) composed of these polymer charge transport materials is excellent in scratch resistance and wear resistance.
As the polymer charge transporting material, any of the hole charge transporting materials and electron transporting polymer charge transporting materials can be used basically. A polymer charge transport material is more effectively used.

  A known material can be used as the hole-transporting polymer charge transporting material, and in particular, a polycarbonate containing a triarylamine structure in the main chain and / or side chain is preferably used. Among these, polymer charge transport materials represented by the following formulas (III) to (XII) are favorably used, and examples thereof are shown below.

式中、Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立して置換もしくは無置換のアルキル基またはハロゲン原子、Ｒ_４は水素原子または置換もしくは無置換のアルキル基、Ｒ_５、Ｒ_６は置換もしくは無置換のアリール基、ｏ、ｐ、ｑはそれぞれ独立して０〜４の整数、ｋ、ｊは組成を表わし、０．１≦ｋ≦１、０≦ｊ≦０．９、ｎは繰り返し単位数を表わし５〜５０００の整数である。Ｘは脂肪族の２価基、環状脂肪族の２価基、または下記一般式で表わされる２価基を表わす。尚、（III）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₁ , R ₂ and R ₃ are each independently a substituted or unsubstituted alkyl group or a halogen atom, R ₄ is a hydrogen atom or a substituted or unsubstituted alkyl group, and R ₅ and R ₆ are substituted or unsubstituted. Substituted aryl group, o, p, q are each independently an integer of 0-4, k, j are compositions, 0.1 ≦ k ≦ 1, 0 ≦ j ≦ 0.9, n is the number of repeating units Represents an integer of 5 to 5000. X represents an aliphatic divalent group, a cycloaliphatic divalent group, or a divalent group represented by the following general formula. In the formula (III), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

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

R ₁₀₁ and R ₁₀₂ each independently represents a substituted or unsubstituted alkyl group, aryl group or halogen atom. l and m are integers of 0 to 4, Y is a single bond, a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms, —O—, —S—, —SO—, —SO ₂ —. , -CO-, -CO-O-Z-O-CO- (wherein Z represents an aliphatic divalent group), or

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

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

式中、Ｒ_７、Ｒ_８は置換もしくは無置換のアリール基、Ａｒ_１、Ａｒ_２、Ａｒ_３は同一または異なるアリレン基を表わす。Ｘ、ｋ、ｊおよびｎは、前記（III）式の場合と同じである。尚、（IV）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₇ and R ₈ represent a substituted or unsubstituted aryl group, and Ar ₁ , Ar ₂ , and Ar ₃ represent the same or different arylene groups. X, k, j and n are the same as those in the above formula (III). In the formula (IV), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

式中、Ｒ_９、Ｒ_１０は置換もしくは無置換のアリール基、Ａｒ_４、Ａｒ_５、Ａｒ_６は同一または異なるアリレン基を表わす。Ｘ、ｋ、ｊおよびｎは、前記（III）式の場合と同じである。尚、（Ｖ）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₉ and R ₁₀ represent a substituted or unsubstituted aryl group, and Ar ₄ , Ar ₅ , and Ar ₆ represent the same or different arylene groups. X, k, j and n are the same as those in the above formula (III). In the formula (V), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

式中、Ｒ_１１、Ｒ_１２は置換もしくは無置換のアリール基、Ａｒ_７、Ａｒ_８、Ａｒ_９は同一または異なるアリレン基、ｐは１〜５の整数を表わす。Ｘ、ｋ、ｊおよびｎは、前記（III）式の場合と同じである。尚、（VI）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₁₁ and R ₁₂ are substituted or unsubstituted aryl groups, Ar ₇ , Ar ₈ and Ar ₉ are the same or different arylene groups, and p represents an integer of 1 to 5. X, k, j and n are the same as those in the above formula (III). In the formula (VI), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

式中、Ｒ_１３、Ｒ_１４は置換もしくは無置換のアリール基、Ａｒ_１０、Ａｒ_１１、Ａｒ_１２は同一または異なるアリレン基、Ｘ_１、Ｘ_２は置換もしくは無置換のエチレン基、または置換もしくは無置換のビニレン基を表わす。Ｘ、ｋ、ｊおよびｎは、前記（III）式の場合と同じである。尚、（VII）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₁₃ and R ₁₄ are substituted or unsubstituted aryl groups, Ar ₁₀ , Ar ₁₁ and Ar ₁₂ are the same or different arylene groups, X ₁ and X ₂ are substituted or unsubstituted ethylene groups, or substituted or unsubstituted Represents a substituted vinylene group. X, k, j and n are the same as those in the above formula (III). In the formula (VII), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

式中、Ｒ_１５、Ｒ_１６、Ｒ_１７、Ｒ_１８は置換もしくは無置換のアリール基、Ａｒ_１３、Ａｒ_１４、Ａｒ_１５、Ａｒ_１６は同一または異なるアリレン基、Ｙ_１、Ｙ_２、Ｙ_３は単結合、置換もしくは無置換のアルキレン基、置換もしくは無置換のシクロアルキレン基、置換もしくは無置換のアルキレンエーテル基、酸素原子、硫黄原子、ビニレン基を表わし同一であっても異なってもよい。Ｘ、ｋ、ｊおよびｎは、前記（III）式の場合と同じである。尚、（VIII）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₁₅ , R ₁₆ , R ₁₇ , R ₁₈ are substituted or unsubstituted aryl groups, Ar ₁₃ , Ar ₁₄ , Ar ₁₅ , Ar ₁₆ are the same or different arylene groups, Y ₁ , Y ₂ , Y ₃ are A single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group may be the same or different. X, k, j and n are the same as those in the above formula (III). In the formula (VIII), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

式中、Ｒ_１９、Ｒ_２０は水素原子、置換もしくは無置換のアリール基を表わし、Ｒ_１９とＲ_２０は環を形成していてもよい。Ａｒ_１７、Ａｒ_１８、Ａｒ_１９は同一または異なるアリレン基を表わす。Ｘ、ｋ、ｊおよびｎは、前記（III）式の場合と同じである。尚、（IX）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₁₉ and R _{20 each} represent a hydrogen atom or a substituted or unsubstituted aryl group, and R ₁₉ and R ₂₀ may form a ring. Ar ₁₇ , Ar ₁₈ and Ar ₁₉ represent the same or different arylene groups. X, k, j and n are the same as those in the above formula (III). In the formula (IX), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

式中、Ｒ_２１は置換もしくは無置換のアリール基、Ａｒ_２０、Ａｒ_２１、Ａｒ_２２、Ａｒ_２３は同一または異なるアリレン基を表わす。Ｘ、ｋ、ｊおよびｎは、前記（III）式の場合と同じである。尚、（Ｘ）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₂₁ represents a substituted or unsubstituted aryl group, and Ar ₂₀ , Ar ₂₁ , Ar ₂₂ , and Ar ₂₃ represent the same or different arylene groups. X, k, j and n are the same as those in the above formula (III). In the formula (X), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

式中、Ｒ_２２、Ｒ_２３、Ｒ_２４、Ｒ_２５は置換もしくは無置換のアリール基、Ａｒ_２４、Ａｒ_２５、Ａｒ_２６、Ａｒ_２７、Ａｒ_２８は同一または異なるアリレン基を表わす。Ｘ、ｋ、ｊおよびｎは、前記（III）式の場合と同じである。尚、（XI）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₂₂ , R ₂₃ , R ₂₄ and R ₂₅ represent a substituted or unsubstituted aryl group, and Ar ₂₄ , Ar ₂₅ , Ar ₂₆ , Ar ₂₇ and Ar ₂₈ represent the same or different arylene groups. X, k, j and n are the same as those in the above formula (III). In the formula (XI), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

式中、Ｒ_２６、Ｒ_２７は置換もしくは無置換のアリール基、Ａｒ_２９、Ａｒ_３０、Ａｒ_３１は同一または異なるアリレン基を表わす。Ｘ、ｋ、ｊおよびｎは、前記（III）式の場合と同じである。尚、（XII）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₂₆ and R ₂₇ represent a substituted or unsubstituted aryl group, and Ar ₂₉ , Ar ₃₀ and Ar ₃₁ represent the same or different arylene groups. X, k, j and n are the same as those in the above formula (III). In the formula (XII), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

  As other hole transporting polymer charge transport materials used in the photocharge charge layer, copolymers of known monomers, block polymers, graft polymers, and star polymers can also be used. Further, for example, as disclosed in JP-A-3-109406, JP-A-5-216249, JP-A-2000-206723, JP-A-2001-34001, etc. A polymer having a two-dimensional or three-dimensional crosslinked structure can be finally used by performing a curing reaction or a crosslinking reaction after film formation in the state of a monomer or oligomer having a group.

In the image forming process, the electrophotographic photosensitive member of the present invention rubs against a developer, transfer paper, a cleaning member, etc., and the photocharged charging layer (13) on the surface of the photosensitive member is mechanically loaded. It may be damaged or worn. Further, the photocharged charge layer (13) on the surface of the photosensitive member may be locally damaged by contact with various members when attached to the image forming apparatus or when detached from the image forming apparatus. There is.
The local flaws and wear parts of the photocharge charge layer (13) have less charge generation material, or if the flaws and wear are severe, the charge generation material is lost and the photocharge charge function, which is a feature of the present invention, is reduced. End up.
For this reason, the charged portion of the photocharged charge layer has a lower charging potential than the non-scratched or worn portion, and the uniformity of the electrostatic charge latent image is impaired. Abnormal images are likely to occur.

In general, the mechanical strength of the organic photoconductive film can be reinforced by a binder resin. However, if the amount of the insulating polymer resin is increased, the charge transport property is lowered and the generation efficiency of the photocarrier is lowered. By using a polymer charge transport material having both a charge transport function and a binder resin function as in the present invention, formation of a photocharge charge layer with higher scratch resistance and wear resistance without lowering the photocharge efficiency. Enable. Further, by using a cross-linked polymeric charge transport material, the film charge layer has a higher film hardness, and the scratch resistance and abrasion resistance of the photoreceptor can be further enhanced. As described above, the use of the polymer charge transport material for the photocharge charging layer provides a photoconductor capable of forming a latent electrostatic image by photocharge charging with higher durability, an image forming method, and an image forming apparatus. It is very effective.
In addition, the photocharged charge layer (13) may contain a filler in order to enhance the film strength of the layer. Fillers that can be used include organic fillers and inorganic fillers.

  Examples of the organic filler material include fluororesin powder such as polytetrafluoroethylene, silicone resin powder, and a-carbon powder. Inorganic filler materials include silica, tin oxide, zinc oxide, titanium oxide, alumina, and oxide. Metal oxides such as zirconium, indium oxide, antimony oxide, bismuth oxide, calcium oxide, tin oxide doped with antimony, indium oxide doped with tin, metal fluorides such as tin fluoride, calcium fluoride, aluminum fluoride, Examples thereof include inorganic materials such as potassium titanate and boron nitride. Among these fillers, the use of inorganic fillers is advantageous for improving the wear resistance from the viewpoint of the hardness of the fillers. Further, as a filler effective for improving the image quality, a filler having high electrical insulation is preferable, and silica, titanium oxide, alumina, zinc oxide, zirconium oxide, and the like can be used particularly effectively. These fillers having high electrical insulation can be mixed with two or more fillers having high electrical insulation or other fillers.

  In the electrophotographic photoreceptor of the present invention, when removing the residual charge on the photoreceptor, exposure for static elimination may be performed using light in the photosensitive wavelength region of the photosensitive layer, but it is used for static elimination. The exposure needs to be sufficiently transmitted through the photocharged charge layer. As described above, the filler added to enhance the film strength should not interfere with the transmission of the static elimination exposure. Therefore, it is necessary to sufficiently disperse and ensure the transmittance of the static elimination exposure in the same manner as in the case where no filler is added. For this purpose, among the above-mentioned fillers, those having a sufficiently small primary particle size (preferably having a primary particle size of 0.3 μm or less) and those having good dispersibility (dispersing agents and dispersing aids as necessary) Used) is used effectively.

<Conductive support>
As the conductive support (11), a material having a volume resistance of 10 ¹⁰ Ω · cm or less, for example, a metal such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, oxidation A metal oxide such as indium is deposited or sputtered on a film or cylindrical plastic or paper, or a plate made of aluminum, aluminum alloy, nickel, stainless steel or the like, and extruded or drawn. After forming the tube, it is possible to use a tube that has been surface-treated by cutting, superfinishing, polishing or the like. Endless nickel belts and endless stainless steel belts can also be used as the conductive support.
In the present invention, when an endless belt-like photoconductor is used, the contact portion between the photocharge charging layer and the charging member can be lengthened in the driving direction of the photoconductor, and the voltage application time can be increased, so that the charge charging efficiency As a result, the formation of a uniform and stable electrostatic latent image having a high charging potential is performed. Therefore, it is very effective to use an endless belt-like photoconductor.

  In addition, the conductive support dispersed in a suitable binder resin and coated on the support can also be used as the conductive support (11) of the present invention. Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc and silver, or metal oxide powder such as conductive tin oxide and ITO. It is done.

The binder resin used simultaneously is polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. , Polyvinyl acetate, poly vinylidene, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, Examples thereof include thermoplastic, thermosetting resins, and photocurable resins such as melamine resin, urethane resin, phenol resin, and alkyd resin. Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.
Furthermore, a conductive layer is formed by a heat shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, or fluororesin on a suitable cylindrical substrate. What is provided can also be used favorably as the conductive support of the present invention.

<Photosensitive layer>
The photosensitive layer in the present invention mainly has two functions.
The first function is to efficiently neutralize unnecessary static charges remaining on the photosensitive member after forming one image using light in the photosensitive region of the photosensitive layer in order to form the next image. is there.
For this purpose, it is preferable that the photosensitive layer has a high neutralization light absorption rate and a high charge generation efficiency by light.

The second function is to amplify the potential of the electrostatic charge latent image formed by photocharge charging.
In the present invention, the charge charged in the photocharged charge layer by image exposure and voltage application and the charge of the opposite polarity induced on the conductive support side are opposed to each other across the photosensitive layer, and the potential of the electrostatic charge latent image is determined. Is expressed. Therefore, the photosensitive layer needs to function as a capacitor, and the potential amplification effect increases as the electrostatic capacitance of the photosensitive layer decreases. In general, an organic material has a dielectric constant smaller than that of an inorganic material, and in this respect, it is effective to use an organic material for the photosensitive layer.

The photosensitive layer (12) in the present invention may be a single layer type or a multilayer type, but here, for convenience of explanation, a multilayer type will be described first. FIG. 3 shows a layer structure of an example of the photoreceptor of the invention having a laminated photosensitive layer.
In this case, the structure of the photoreceptor is such that a charge generation layer (12a) and a charge transport layer (12b) are provided as a photosensitive layer on a conductive support (11), and a photocharge charge layer (13) is laminated on the surface. Yes. Further, an undercoat layer (14) is provided between the conductive support and the photosensitive layer.
First, the charge generation layer (12a) will be described. The charge generation layer has a function of absorbing positive and negative exposure and generating positive and negative photocharges. Therefore, the charge generation layer is a layer mainly composed of a charge generation material, and a binder resin may be used as necessary. As the charge generation material, inorganic materials and organic materials can be used.

  Inorganic materials include crystalline selenium, amorphous selenium, selenium-tellurium, selenium-tellurium-halogen, selenium-arsenic compounds, and amorphous silicon. In amorphous silicon, dangling bonds that are terminated with hydrogen atoms or halogen atoms, or those that are doped with boron atoms, phosphorus atoms, or the like are preferably used.

  On the other hand, a known material can be used as the organic material. 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, dibenzothiophene skeleton Azo pigments having fluorenone skeleton, azo pigments having oxadiazole skeleton, azo pigments having bis-stilbene skeleton, azo pigments having distyryl oxadiazole skeleton, azo pigments having 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.

  As a binder resin used as necessary for the charge generation layer, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, Polyacrylamide or the like is used. These binder resins can be used alone or as a mixture of two or more. Furthermore, you may add a charge transport material as needed.

  Examples of the hole transporting material include the electron donating materials shown below and are used favorably. For example, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, triphenylamine derivatives, 9- (p-diethylaminostyrylanthracene), 1,1-bis- (4-dibenzylaminophenyl) propane, styrylanthracene, styryl Examples include pyrazoline, phenylhydrazones, α-phenylstilbene derivatives, thiazole derivatives, triazole derivatives, phenazine derivatives, acridine derivatives, benzofuran derivatives, benzimidazole derivatives, and thiophene derivatives. These hole transport materials can be used alone or as a mixture of two or more.

  Methods for forming the charge generation layer are roughly classified into a vacuum thin film preparation method and a casting method from a solution dispersion system. As the former method, a vacuum deposition method, a glow discharge decomposition method, an ion plating method, a sputtering method, a reactive sputtering method, a CVD method, or the like is used, and the above-described inorganic materials and organic materials can be satisfactorily formed. In addition, in order to provide the charge generation layer by the casting method described later, the inorganic or organic charge generation material described above is used together with a binder resin, if necessary, using a solvent such as tetrahydrofuran, cyclohexanone, dioxane, dichloroethane, butanone, ball mill, atom It can be formed by dispersing with a lighter, sand mill or the like and applying the solution after diluting the dispersion appropriately. The coating can be performed using a dip coating method, a spray coating method, a bead coating method, or the like. The thickness of the charge generation layer provided as described above is suitably about 0.01 to 5 μm, preferably 0.05 to 2 μm.

Next, the charge transport layer (12b) will be described.
The charge transport layer receives the charge generated in the charge generation layer, transports the charge to the interface with the photocharge charge layer (and thus the surface of the photoreceptor), and neutralizes the residual charge in or on the photocharge charge layer. In addition, it has a function of neutralizing residual charges on the photosensitive member for the next image formation. Therefore, the charge transport layer is a layer mainly composed of a charge transport material, and is formed by dissolving and coating the charge transport material together with a binder resin as necessary. Binder resins that can be used as required include polycarbonate with good film properties (bisphenol A type, bisphenol Z type, bisphenol C type, or copolymers thereof), polyarylate, polysulfone, polyester, methacrylic resin. Polystyrene, polyvinyl acetate, epoxy resin, phenoxy resin, etc. are used. These binders can be used alone or as a mixture of two or more.

The charge transport materials used in the charge transport layer include oxazole derivatives, oxadiazole derivatives (described in JP-A Nos. 52-139065 and 52-139066), imidazole derivatives, triphenylamine derivatives, benzidine. Derivatives (described in JP-B-58-32372), α-phenylstilbene derivatives (described in JP-A-58-199093), hydrazone derivatives (JP-A-55-154955, JP-A-55-156554) JP, 55-52063, JP 56-81850, etc.), triphenylmethane derivatives (described in JP-B 51-10983), anthracene derivatives (JP 51-51). 94829), styryl derivatives (Japanese Patent Laid-Open No. 56-29245, Japanese Patent Laid-Open No. 58- Described in 98043 JP), described in JP-carbazole derivatives (JP-58-58552), or the like can be used pyrene derivatives. Moreover, the polymeric charge transport substance which can be used for the above-mentioned photocharge charge layer can also be used.
As described above, the photosensitive layer is required to have a function of amplifying the potential of the electrostatic latent image. It is effective to increase the thickness of the charge transport layer to reduce the capacitance of the photosensitive layer.

In the image forming method using the photoconductor of the present invention, the electrostatic charge latent image on the photoconductor is formed by a photocharged charge layer on the surface of the photoconductor, and the photoconductive layer is for discharging the surface charge. Therefore, unlike the photosensitive layer of a normal electrophotographic photosensitive member that forms an electrostatic latent image, there is no need to worry about a decrease in resolving power due to charge diffusion caused by increasing the thickness of the charge transport layer.
The thickness of the charge transport layer is preferably 10 μm to 500 μm. If the thickness is less than 10 μm, the electrostatic capacity of the photoreceptor increases, so that the potential developed by photocharge charging of the image exposure unit is low, and the potential contrast of the electrostatic latent image is low. If it exceeds 500 μm, the movement time of the optical carrier becomes long, and the response of the photostatic discharge becomes low. More preferably, it is 20-300 micrometers.

  Next, the case where the photosensitive layer has a single layer structure will be described. A photoreceptor in which the above-described charge generating material is dispersed in a binder resin can be used. The single-layer photosensitive layer can be formed by dissolving or dispersing a charge generating substance, a charge transporting substance, and a binder resin in an appropriate solvent, and applying and drying them. Further, the photosensitive layer may be a function separation type to which the above-described charge transport material is added, and can be used satisfactorily. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.

As the binder resin, in addition to the binder resin previously mentioned in the section of the charge transport layer (12b) as it is, the binder resin mentioned in the section of the charge generation layer (12a) may be mixed and used. The amount of the charge generating material with respect to 100 parts by weight of the binder resin is preferably 5 to 40 parts by weight. The amount of the charge transport material is preferably 0 to 190 parts by weight, and more preferably 50 to 150 parts by weight. The single-layer photosensitive layer is formed by dip coating or spray coating with a coating solution dispersed with a disperser using a solvent such as tetrahydrofuran, dioxane, dichloroethane, or cyclohexane, together with a charge generating material and a binder transport resin if necessary. It can be formed by coating with a bead coat or the like. The film thickness of the single photosensitive layer is suitably about 10 to 300 μm. If the thickness is less than 10 μm, the electrostatic capacity of the photosensitive member increases, so that the potential developed by photocharge charging of the exposed portion decreases, and the contrast of the electrostatic charge latent image decreases.
If it exceeds 300 μm, the movement time of the photocarrier in the photosensitive layer becomes long, and the responsiveness of photostatic discharge becomes low. More preferably, it is 20-200 micrometers.

<Underlayer>
Next, the undercoat layer (14) will be described.
In the electrophotographic photosensitive member of the present invention, an undercoat is optionally provided between the conductive support and the photosensitive layer (between the conductive support and the charge generation layer when the photosensitive layer is a laminated type). A layer can be provided. The undercoat layer improves adhesiveness, charge blocking, improves the coatability of the upper layer, reduces residual potential, etc.Furthermore, a coherent light source such as a fluorescent lamp or a laser is used as static elimination light. It is provided for the purpose of preventing non-uniform static elimination in the form of moire based on optical interference that occurs when used.
The undercoat layer generally contains a resin as a main component. However, considering that the photosensitive layer is applied with a solvent on these resins, the resin may be a resin having a high solvent resistance with respect to a general organic solvent. desirable.

  Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and polyacrylic acid, alcohol-soluble resins such as copolymerizable nylon and methoxymethylated nylon, polyurethane, melamine resins, alkyd-melamine resins, and epoxy resins. And a curable resin that forms a three-dimensional network structure. Further, fine powders such as metal oxides exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like, or metal sulfides and metal nitrides may be added.

Furthermore, 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 as the undercoat layer of the present invention is also useful. In addition to this, the undercoat layer of the present invention is formed by anodizing aluminum oxide, organic matter such as polyparaxylylene (parylene), SiO, SnO ₂ , TiO ₂ , ITO, CeO _2, etc. What provided the inorganic substance with the vacuum thin film preparation method can also be used satisfactorily.
Further, in the photoreceptor of the present invention, an antioxidant can be added for the purpose of preventing the decrease in sensitivity and the increase in residual potential, in order to improve the environmental properties. The antioxidant may be added to any layer containing an organic substance, but good results are obtained when it is added to a layer containing a charge transport material.

Examples of the antioxidant that can be used in the present invention include the following.
(Monophenol compound)
2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3,5-di-t-butyl-4 -Hydroxyphenyl) propionate and the like.

(Bisphenol compound)
2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2′-methylene-bis- (4-ethyl-6-tert-butylphenol), 4,4′-thiobis- ( 3-methyl-6-t-butylphenol), 4,4′-butylidenebis- (3-methyl-6-t-butylphenol) and the like.

(High molecular phenolic compounds)
1,1,3-tris- (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t- Butyl-4-hydroxybenzyl) benzene, tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, bis [3,3′-bis ( 4'-hydroxy-3'-t-butylphenyl) butyric acid] cricol ester, tocopherols and the like.

(Paraphenylenediamines)
N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N'- Di-isopropyl-p-phenylenediamine, N, N′-dimethyl-N, N′-di-t-butyl-p-phenylenediamine and the like.

(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 and the like.

(Organic sulfur compounds)
Dilauryl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, ditetradecyl-3,3′-thiodipropionate and the like.

(Organic phosphorus compounds)
Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine, and the like.

  These compounds are known as antioxidants such as rubbers, plastics and fats and oils, and commercially available products can be easily obtained. The addition amount of the antioxidant in the present invention is preferably 0.1 to 100 parts by weight, more preferably 2 to 30 parts by weight with respect to 100 parts by weight of the charge transport material.

Next, the image forming method and the image forming apparatus of the present invention will be described in detail with reference to the drawings.
FIG. 4 is a schematic diagram for explaining the image forming apparatus, which is used for image formation in the embodiment of the present invention. In FIG. 4, a photoreceptor (1) has a photosensitive layer having photosensitivity to at least static elimination light and a photocharged charging layer containing a charge generating substance that generates charges upon image exposure on a conductive support. It is a photoreceptor.

  The image exposure means (2) can be used as long as it is a light source containing light of a wavelength that is absorbed by the photocharged charge layer of the photoreceptor (1). For example, a halogen lamp, a fluorescent lamp, a mercury lamp, a xenon lamp, a laser light source, and an LED can be used. In general, a photoconductor is easily deteriorated by ultraviolet rays. Therefore, it is preferable to use light of 400 nm or more as image light. For this purpose, an image exposure means incorporating a means for cutting off ultraviolet light such as a filter, an optical diffraction grating, or an apparatus can be used. In addition, the image exposure means can be integrated with other members such as a voltage applying member and a photosensitive member. For example, it is also possible to incorporate an image exposure means inside the transparent voltage application member in which the surface of a cylindrical hollow body made of glass or plastic is made translucent and conductive as the voltage application means. By installing the image exposure unit in this way, not only can the image forming apparatus be designed in a compact manner, but also the image exposure and voltage application can be performed at the same time, so that the light charging effect can be enhanced. .

  In image exposure, it is important that the photocharge charging layer sufficiently absorbs light, but it is also important that light does not reach the photosensitive layer (charge generation layer). In the state of FIG. 2C, when the image exposure sufficiently reaches the photosensitive layer (charge generation layer), photocarriers are generated in the same manner as in the case of photostatic discharge of the photoreceptor. For this reason, one of the positive and negative charges stored in the photocharge charge layer (which is determined by the charge polarity) is canceled, and the charged potential of the exposed portion of image exposure may become insufficient. is there.

For this reason, in the image forming apparatus of the present invention, the photocharged layer preferably absorbs 80% or more, more preferably 100%, of light used for image exposure.
In addition, it is effective in the present invention to use light in a wavelength region that is not absorbed by the photosensitive layer (charge generation layer) as image exposure. In other words, it is sufficient that the photocharge charging layer can sufficiently absorb the image exposure as described above. However, if the charge generation material used in the photosensitive layer (charge generation layer) does not absorb the image exposure, the photocarrier is not absorbed. It does not occur and does not cause the above problems.

Such an example will be described with reference to the drawings. Assume that the charge generation material (CGM A) shown in FIG. 8 is used as the charge generation material of the photosensitive layer, and the charge generation material (CGM C) is used as the charge generation material of the photocharge charge layer. At this time, by setting the image exposure wavelength to light in the vicinity of 800 nm, the absorption of CGMC is very large (absorption efficiency is high), and the charge generation substance concentration in the photocharge charge layer is increased, or the photocharge charge is performed. By increasing the thickness of the layer, image exposure can be absorbed by 80% or more (preferably 100%). Considering the influence on other characteristics of the photoconductor, etc., even if the charge generation material concentration and film thickness cannot be set to the above levels, the charge generation material (CGM A) used for the photosensitive layer (charge generation layer) There is no absorption in the vicinity of 800 nm, and even if image exposure partially passes through the photocharged charge layer, photocarrier generation does not occur in the photosensitive layer (charge generation layer), and the photosensitive member has a sufficient potential contrast. A latent charge image is formed.

In this case, the image exposure can be further improved by using substantially monochromatic light having a very narrow half-value width (such that the half-value width is within ± 30 nm with respect to the center wavelength) like laser light or LED light. Expressed. In order to realize such a writing wavelength, in addition to using LD light or LED light as described above, it is also possible to use a white light source in combination with a filter capable of cutting the short wavelength side and the long wavelength side. Is possible.
The voltage application means (3) is in contact with the photoreceptor (1) and applies a voltage to the photoreceptor (1) by a power source (not shown) simultaneously with image exposure on the photoreceptor or after image exposure to charge the photocharge charging layer. Is charged, the photosensitive member (1) is charged to a desired potential, and an electrostatic charge latent image is formed.
For this reason, the voltage application member in contact with the surface of the photoreceptor needs to have sufficient conductivity.
The conductivity can be described by the resistance value of the voltage application member, and is 10 ¹⁰ Ω · cm or less, preferably 10 ⁹ Ω · cm or less, more preferably 10 ⁷ Ω · cm or less.

As the voltage application member, a material obtained by processing a conductive material such as metal, conductive rubber, or conductive plastic into a roller shape, a plate shape, or a brush shape can be used. An elastic conductive roller in which conductive rubber in which conductive fine particles such as carbon are dispersed in silicone rubber or urethane rubber is coated on a conductive core roll such as metal can be used. The resistance of the conductive roller is preferably 10 ¹⁰ Ω · cm or less. In the embodiment of the present invention, a conductive roller was used in which a conductive urethane elastic layer having a volume resistivity of about 10 ⁴ Ω · cm was provided on a stainless steel shaft having a diameter of 8 mm.
A magnet roll fixedly supported; a non-magnetic sleeve rotatably provided on the outside of the magnet roll; and magnetic particles adsorbed on the non-magnetic sleeve by the magnetic force of the magnet roll. It is also possible to use a so-called magnetic brush voltage application member that is designed so that a magnetic brush is formed by raising a magnetic force and the magnetic brush and the photosensitive member come into contact with each other.

  Furthermore, conductive fibers obtained by processing conductive plastics, so-called conductive brushes or conductive carbon fiber cloths in which they are densely planted on conductive metal rolls or plate-like supports, rolls or plate-like supports. It is also possible to use a conductive woven fabric attached to the fabric.

Further, as described above, a transparent voltage applying member in which the surface of the light-transmitting hollow body is processed to be translucent and conductive may be used in order to be integrated with the image exposure means. The light-transmitting hollow body is not particularly limited as long as it is transparent to the image exposure light source. For example, glass (pyrex (registered trademark) glass, borosilicate glass, soda glass, etc.), quartz, sapphire and the like are transparent. Inorganic materials, fluororesins, polyesters, polycarbonates, polyethylene, polyethylene terephthalate, vinylon, epoxy resins and other transparent resins are used. As the shape of the hollow belt, a roller shape or an endless belt shape can be used effectively. Transparent conductive materials such as ITO (indium tin oxide), lead oxide, indium oxide, copper iodide, etc. can be formed on the surface directly or dispersed in resin, or aluminum, nickel, A metal such as gold or hastelloy may be formed thin enough to be translucent. When the conductive layer is provided, it can be provided by a method such as sputtering or a wet method. When a metal is provided on the surface, a vapor deposition method or sputtering is used.
After forming an electrostatic charge latent image on the surface of the photoreceptor, a toner image is formed by the developing means (4).

As the developing system used in the present invention, all known developing means conventionally used in electrophotography can be used.
The development of conventional laser printers and digital copiers using electrophotography is mainly reversal development using toner charged to the same polarity as the charged polarity on the surface of the photoreceptor.
In the electrostatic latent image of the present invention, the potential of the exposed portion is higher than the potential of the non-exposed portion.
Therefore, for the development used in the present invention, so-called regular development using a toner charged with a polarity opposite to the polarity of the charged charge in the photocharge charging is effectively used.
Of course, reversal development may be performed, but in this case, the toner image formed on the surface of the toner photoconductor on the background becomes an image obtained by reversing the original image.

Next, the toner image developed on the photosensitive member is transferred to a transfer member such as transfer paper (8) by the transfer means (5). In addition to the direct transfer to the transfer member as shown in FIG. 4, a so-called intermediate transfer method in which the toner image is transferred to the intermediate transfer member and then transferred to the final transfer member may be used.
As the transfer voltage applied to the transfer member during transfer, a voltage having a polarity opposite to the charging polarity of the toner is applied.
Thereafter, the toner image is fixed on the transfer paper by fixing means (not shown).
Residual toner on the photoreceptor (1) is removed by a cleaning means (6) such as a cleaning fur brush or a cleaning blade.
Further, residual charges remain on the surface of the photoreceptor after the transfer process and the cleaning process.
For this reason, the surface of the photoreceptor must be neutralized before the next image formation.

As a static elimination method,
(1) Heating static elimination (2) The static elimination method conventionally used in electrophotography by discharge of direct current or alternating voltage opposite to the residual charge is possible, but the photosensitive layer having the photosensitive layer of the present invention. In the case of a body, the photosensitive layer can be effectively neutralized by exposing the photosensitive layer with light in the photosensitive wavelength region.

Any static elimination exposure means (7) can be used as long as it is an exposure means generally used in electrophotography. For example, a halogen lamp, fluorescent lamp, mercury lamp, xenon lamp, LD, LED, phosphor dot array, or the like is used.
In general, a photoconductor is easily deteriorated by ultraviolet rays, and therefore, it is preferable to use light having a wavelength of 400 nm or more as static elimination light. Therefore, as the exposure means for static elimination, an apparatus incorporating ultraviolet light cutting means such as a filter and an optical diffraction grating can be used as in the case of the image exposure means.
Furthermore, the exposure wavelength of the light source used here is preferably as high as possible in the photocharged charge layer to increase the absorption efficiency in the photosensitive layer, and the transmittance in the photocharged charge layer is as high as possible. It is preferable to use a wavelength of 50% or more.

  This point will be described with reference to FIG. FIG. 8 shows a charge generation material (denoted as CGM A in the figure) used for the photocharge charge layer and a charge generation substance (denoted as CGM C in the figure) used for the photosensitive layer (charge generation layer). The relationship between the absorption spectrum and the light source wavelength region for static elimination exposure was shown. A broken line (denoted as wavelength A) parallel to the Y axis in FIG. 8 is a wavelength of 50% transmittance in CGM A. By using static elimination exposure at a wavelength longer than this wavelength, sufficient image exposure reaches the photosensitive layer (charge generation layer), and sufficient photosensitivity for static elimination can be obtained. Further, it is preferable to perform exposure for static elimination using light having a wavelength that does not absorb the organic pigment contained in the photocharged charge layer.

  The wavelength without absorption of the organic pigment here is as follows. In general terms, “no absorption” literally represents no absorption (ie, the state of zero absorbance in FIG. 8). However, the state of the organic pigment dispersion film is very good in dispersion and the primary particles are not submicron or less, so that the absorbance hardly shows 0 in optical measurement. Therefore, in the present invention, the case where the transmittance is 90% or more in the state of the pigment dispersion film is defined as the “no absorption” state.

  The solid line (denoted as wavelength B) parallel to the Y-axis shown in FIG. 8 is the boundary line of the wavelength region that shows a transmittance greater than 90% of the absorption in CGM A. By performing such static elimination exposure on the longer wavelength side than the wavelength B, it is possible to design a photoconductor in which a reduction in photosensitivity for static elimination is not substantially recognized, and it is effectively used in the image forming apparatus of the present invention. . At this time, the effect of static elimination is further increased by using substantially monochromatic light having an extremely narrow half-value width (such that the half-value width is within ± 30 nm with respect to the center wavelength) like laser light or LED light. Is expressed. In order to realize such a static elimination light wavelength, in addition to using LD light or LED light as described above, a white light source is used in combination with a filter capable of cutting the short wavelength side and the long wavelength side. Is also possible. Residual charges on the surface of the photoconductor are efficiently removed by this static elimination exposure.

  After forming an electrostatic charge latent image on the surface of the photoreceptor, a toner image is formed by the developing means (4). The toner image formed on the surface of the photoconductor is transferred to a transfer body such as transfer paper (8) by the transfer means (5). In addition to the direct transfer to the transfer member as shown in FIG. 4, a so-called intermediate transfer method in which the toner image is transferred to the intermediate transfer member and then transferred to the final transfer member may be used. Thereafter, the toner image is fixed on the transfer paper by fixing means (not shown). Residual toner on the photoreceptor (1) is removed by a cleaning means (6) such as a cleaning fur brush or a cleaning blade.

FIG. 5 shows another example of an electrophotographic process and apparatus according to the present invention. The photoreceptor (1) is an endless belt-shaped photoreceptor having at least a photosensitive layer and a photocharge charging layer containing a charge generating substance on a conductive support. This endless belt-like photoconductor is driven and supported by a driving roller and driven rollers (9a, 9b) and moves in the direction of the arrow. The photoreceptor (1) is charged and charged by the image exposure means (2) and the voltage application means (3) to form an electrostatic charge latent image.
This electrostatic charge latent image is developed with toner by the developing means (4) and transferred onto a transfer member such as paper by the transferring means (5). The image on the transfer body is fixed by fixing means (not shown).
Residual toner on the photoreceptor (1) is removed by a cleaning means (6) such as a cleaning fur brush or a cleaning blade, and residual charges are removed by a static elimination light source (7), and the next electrophotographic cycle is started.
When the support of the photoconductor (1) is light transmissive, image exposure means, a static elimination light source, etc. are installed inside the belt, and light irradiation is performed from the support side. In this case, there is an advantage that the apparatus becomes compact. The belt-like photosensitive member and the driving / supporting roller can be integrated into a unit so that it can be freely attached to and detached from the apparatus.

  The image forming method and the image forming apparatus of the present invention are not limited to the above examples, and at least the same polarity as the applied voltage by image exposure and voltage application to a photoreceptor having a photocharged charge layer containing a charge generating substance. Any image forming apparatus including the step of forming the electrostatic charge latent image may be used.

  The image forming apparatus as described above may be fixedly incorporated in a copying apparatus, a facsimile machine, or a printer, but may be incorporated in these apparatuses in the form of a process cartridge. A process cartridge is a single device (component) that contains a photosensitive member and includes a charging exposure unit, a voltage applying unit, a developing unit, a cleaning unit, a charge eliminating unit, a transfer unit, and the like.

FIG. 6 shows an example of the process cartridge of the present invention. Around the photoreceptor (1), there are a voltage application roller (charging member) (3), a developing means (4) for supplying an appropriate amount of developer to the surface of the photoreceptor (1), and a blade for cleaning the photoreceptor surface after image transfer. The provided cleaning means (6) is integrated. This cartridge is formed so that it can be detachably handled by an image forming apparatus having means necessary for image formation, such as image exposure means, transfer means, static elimination means, fixing means, and recording paper transport means.
The photoconductor (1) mounted on the cartridge is a photoconductor having at least a photoconductive layer and a photocharged charge layer containing a charge generating substance on a conductive support.

Example 1
<Formation of undercoat layer>
An undercoat layer coating solution having the following composition was applied on an aluminum cylindrical tube having an outer diameter of 100 mmφ by an immersion method so that the film thickness after drying was 3.5 μm, thereby forming an undercoat layer.

(Coating liquid for undercoat layer)
Alkyd resin (Beccosol 1307-60-EL: Dainippon Ink and Chemicals) 3 parts by weight Melamine resin (Super Becamine G-821-60: Dainippon Ink and Chemicals) 2 parts by weight Titanium oxide (CR-EL: Ishihara Sangyo) 20 parts by weight Methyl ethyl ketone 100 parts by weight

<Formation of charge generation layer>
On this undercoat layer, titanyl phthalocyanine pigment (XD spectrum is shown in FIG. 10) 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 has a major peak at 9.4 °, 9.6 °, 24.0 °, and a peak at 7.3 ° as the lowest diffraction peak, Further, the following charge generation layer coating solution containing titanyl phthalocyanine) having no peak between the 7.3 ° peak and the 9.4 ° peak and having no peak at 26.3 °) is immersed. The coating was applied and dried by heating at 110 ° C. for 20 minutes to form a charge generation layer having a thickness of 0.3 μm.
The titanyl phthalocyanine pigment was synthesized according to Synthesis Example 1 described in paragraph No. [0140] of JP-A No. 2001-19871.

(Coating solution for charge generation layer)
5 parts by weight of the above titanyl phthalocyanine pigment 2 parts by weight of butyral resin (ESREC BMS: Sekisui Chemical) 80 parts by weight of methyl ethyl ketone

<Formation of charge transport layer>
Next, dip coating is performed on the charge generation layer using a charge transport layer coating solution containing a charge transport material of the following structural formula (1), pre-drying at 80 ° C. for 10 minutes, and 140 ° C. for 30 minutes Heat drying was performed to form a charge transport layer having a thickness of 40 μm.

(Coating liquid for charge transport layer)
Bisphenol Z-type polycarbonate (viscosity average molecular weight 50,000) 1 part by weight Charge transport material of the following structural formula (1) 1 part by weight Tetrahydrofuran 10 parts by weight

<Formation of photocharged charge layer>
On the charge transport layer thus prepared, the following photocharge charge layer coating solution was applied by spray coating, dried at room temperature, and then heat dried at 160 ° C. for 20 minutes to form a 1 μm thick photocharge charge layer. Then, a photoconductor for charge charging was prepared.

(Photocharged charge layer coating solution)
3 parts by weight of a bisazo pigment of the following structural formula (2) 3 parts by weight of a charge transport material of the following structural formula (3) 1 part by weight of a bisphenol Z-type polycarbonate (viscosity average molecular weight 50,000) 100 parts by weight of tetrahydrofuran 40 parts by weight of cyclohexanone

<Evaluation>
The charge generation layer coating solution and the photocharge charge layer coating solution prepared as described above were each applied and dried on a quartz glass substrate under the same conditions as the photoconductor, and the respective absorption spectra were then commercially available. The absorption spectrum was measured with a spectrophotometer (Hitachi: UV-3100). As a result, the absorption spectrum of the charge generation layer almost coincided with the absorption spectrum of CGM C shown in FIG. 8, and the maximum absorption peak wavelength was 800 nm. Further, the absorption spectrum of the photocharged charge layer almost coincided with the absorption spectrum of CGM A shown in FIG. 8, and the maximum absorption peak wavelength was 583 nm. Further, the transmittance at 645 nm of the photocharged charge layer was 10%. Furthermore, the photocharged charge layer had no absorption at 780 nm.

The photocharge charging characteristics of the photoconductor produced as described above were measured as follows using a surface potential meter (22) constituting the charging characteristic measuring apparatus shown in FIG.
That is, the photoconductor (1) rotating at a speed of 200 mm / s was exposed using an LED (20) having a wavelength region of 645 nm as an exposure light source, and then silicon having a diameter of 16 mm and an electric resistance of 10 ⁴ Ω · cm. A voltage application member (3) made of a rubber roller is brought into contact, a voltage of −500 V is applied in the accompanying state, and the charged potential of the exposure unit is measured by a surface potentiometer (22) installed at a position assuming the developing unit of the image forming apparatus. Was measured. Further, as the charging potential of the non-exposed portion, the charging potential was measured when a voltage of −500 V was applied to the voltage applying member (3) without lighting the LED. The charge potential when the LED is not exposed is V (OFF), the charge potential when the LED is exposed is V (ON), and the electrostatic charge latent image contrast ΔV is obtained by the following equation.

Ｖ（ＯＦＦ）、Ｖ（ＯＮ）、ΔＶはそれぞれ、−２００Ｖ、−４００Ｖ、ΔＶ＝−２００Ｖであった。

V (OFF), V (ON), and ΔV were −200 V, −400 V, and ΔV = −200 V, respectively.

The photoreceptor of Example 1 has sufficient electrostatic contrast for development in electrophotography.
Further, the photosensitive member charged as described above was exposed to light having a length of 700 nm or less using a halogen lamp with a filter that cuts light in a wavelength region shorter than 700 nm as the charge eliminating member (21) shown in FIG. However, the potentials of the exposed part and the non-exposed part were both 0V.

Next, using this photoreceptor, an image was formed by the image forming apparatus shown in FIG. The image forming method will be described below.
Immediately after exposing the photosensitive member (1) to a 600 dpi dot image using an LED having a wavelength region of 645 nm as the image exposure means (2), the voltage application means (3) is made of stainless steel having a diameter of 8 mm. Using a conductive roller provided with a conductive urethane elastic layer having a volume resistivity of about 10 ⁴ Ω · cm on the shaft, this is brought into contact with the surface of the photoreceptor, and a voltage of −500 V is applied to form an electrostatic charge latent image. did. As the developing means (4), a two-component developer composed of a positively charged toner and a magnetic carrier was used, and normal development was performed with a developing bias set to -200V.
The transfer means (5) applied a negative voltage to the conductive charging roller, transferred the toner image on the surface of the photoreceptor onto paper, and fixed it with a heating fixing device (not shown).
The cleaning means (6) for the surface of the photoreceptor used fur brush cleaning. As the charge removal means (7), a halogen lamp with a filter that cuts light in a wavelength region shorter than 700 nm was used, and the charge was removed with light longer than 700 nm.
When an image was formed under the above conditions, a clear dot image without background stain was obtained.

Next, the following forced fatigue test was conducted in order to investigate the deterioration of the photoreceptor when the charging method of the present invention was repeated.
Only 650 nm LED light irradiation, −500 V voltage application and 700 nm or longer light entire surface exposure were repeated 5000 times on the photoconductor to perform a forced fatigue test, and then 25 ° C., 50%, 30 ° C., 85%. When the image was created in the same temperature and humidity environment by the same method as the initial image formation, a clear dot image similar to the initial image with no image blur and image flow was obtained.

(Example 2)
A photoconductor was prepared and evaluated in the same manner as in Example 1 except that the amount of adhesion of the photocharged charge layer was changed so that the transmittance at 645 nm of the photocharged charge layer in Example 1 was 18%. It was.
V (OFF), V (ON), and ΔV were −200 V, −380 V, and ΔV = −180 V, respectively.
Further, when a halogen lamp obtained by applying a filter that cuts light in a wavelength region shorter than 700 nm to a photosensitive member that is charged by lighting an LED is exposed to light longer than 700 nm, the potential of the exposed portion is 0 V. became.
Further, when an image was formed by the image forming apparatus shown in FIG. 4, the initial charging potential of the photosensitive member was −320 V with an applied voltage of −500 V. When image formation was carried out in the same manner as in Example 1, a clear image with no image blur, a uniform halftone portion and no rough feeling was obtained.

(Example 3)
A photoconductor was produced in the same manner as in Example 1 except that the amount of adhesion of the photocharged charge layer was changed so that the transmittance at 645 nm of the photocharged charge layer in Example 1 was 30%. I did it.
As in the case of Example 1, the charging potential when a voltage of −500 V was applied was measured.
V (OFF), V (ON), and ΔV were −150V, −250V, and ΔV = −100V, respectively.
In addition, when a halogen lamp obtained by applying a filter that cuts light in a wavelength region shorter than 700 nm to a photosensitive member that is charged by turning on an LED is exposed to light longer than 700 nm, the potential of the exposed portion is 10 V. became.
Further, when image formation was performed with the image forming apparatus shown in FIG. 4 in the same manner as in Example 1, no image blur occurred, but an image having a slightly lower image density than that in Example 1 was obtained.

Example 4
A photoconductor was prepared in the same manner as in Example 1 except that the compound of the following structural formula (4) was included instead of the charge transport material represented by the structural formula (3) of the photocharged charge layer of Example 1. Similar evaluations were made.

V (OFF), V (ON), and ΔV were −150V, −450V, and ΔV = −300V, respectively.
Further, when a halogen lamp obtained by applying a filter that cuts light in a wavelength region shorter than 700 nm to a photosensitive member that is charged by lighting an LED is exposed to light longer than 700 nm, the potential of the exposed portion is 0 V. became.

  Using this photoreceptor, an image was formed under the same conditions using the same image forming apparatus as in Example 1, and a clear image was obtained. Further, in the same manner as in Example 1, after applying the forced fatigue test by repeating only the voltage application of −500 V and the entire exposure of the laser of 780 nm 10,000 times, the temperature and humidity environment of 25 ° C., 50%, 30 ° C. and 85% When an image was formed by the same method as the initial image formation below, a clear dot image similar to the initial image with no image blur and image flow was obtained.

(Example 5)
A photoconductor was prepared and evaluated in the same manner as in Example 1 except that the charge transport material of the photocharged charge layer in Example 1 was changed to a compound represented by the following structural formula (5).

V (OFF), V (ON), and ΔV were −200 V, −400 V, and ΔV = −200 V, respectively.
In addition, when a halogen lamp obtained by applying a filter that cuts light in a wavelength region shorter than 700 nm to a photosensitive member that is charged by turning on an LED is exposed to light longer than 700 nm, the potential of the exposed portion is 10 V. became.
Using this photoreceptor, an image was formed under the same conditions using the same image forming apparatus as in Example 1. As a result, the image density was slightly lower than that of Example 1, but a clear image was obtained. .

(Example 6)
A photoconductor was prepared in the same manner as in Example 1 except that a bisazo pigment represented by the following structural formula (6) was used as the charge generation material of the photocharge charging layer in Example 1, and charging characteristics were measured in the same manner as in Example 1. Using the apparatus was measured.
V (OFF), V (ON), and ΔV were −200 V, −450 V, and ΔV = −250 V, respectively.
Further, when a halogen lamp obtained by applying a filter that cuts light in a wavelength region shorter than 700 nm to a photosensitive member that is charged by lighting an LED is exposed to light longer than 70 nm, the potential of the exposed portion is 0 V. became.

この感光体を用いて、実施例１と同様の画像形成装置を用いて同じ条件で画像を形成したところ、画像ボケがなく、鮮明な画像が得られた。実施例１と比較してコントラストの高い画像であった。

Using this photoreceptor, an image was formed under the same conditions using the same image forming apparatus as in Example 1. As a result, there was no image blur and a clear image was obtained. Compared with Example 1, the image was high in contrast.

(Example 7)
A photoconductor was prepared in the same manner as in Example 1 except that a bisazo pigment represented by the following structural formula (7) was used as the charge generation material of the photocharge charging layer of Example 1, and the same evaluation was made.
V (OFF), V (ON), and ΔV were −200 V, −320 V, and ΔV = −120 V, respectively.
Further, when a halogen lamp obtained by applying a filter that cuts light in a wavelength region shorter than 700 nm to a photosensitive member that is charged by lighting an LED is exposed to light longer than 700 nm, the potential of the exposed portion is 0 V. became.

この感光体を用いて、実施例１と同様の画像形成装置を用いて同じ条件で画像を形成したところ、実施例１と比較してやや濃度の低い鮮明な画像が得られた。

Using this photoreceptor, an image was formed under the same conditions using the same image forming apparatus as in Example 1. As a result, a clear image having a slightly lower density than that in Example 1 was obtained.

[Comparative Example 1]
A photoconductor was prepared in the same manner as in Example 1 except that the photocharged charge layer was not provided in Example 1.
The charging characteristics were measured by applying a voltage of −500 V in the same manner as in Example 1. V (OFF) = 0V and V (ON) = + 20V.
An electrostatic contrast sufficient for developing for electrophotography with the same polarity as the applied voltage could not be obtained.

Next, a non-contact charging roller for discharge charging is mounted in place of the voltage application roller of the image forming apparatus used in Example 1 using the photoreceptor of Comparative Example 1, and the surface of the photoreceptor is charged by -400 V by discharge. Then, a dot-like electrostatic latent image having an image portion potential of −400 V and a background portion potential of −200 V was formed using the LED of Example 1, and image formation was performed in the same manner as in Example 1. A clear initial image was obtained as in Example 1.
Thereafter, only -400 V charging by corona discharge and entire exposure of light of 700 nm or longer were repeated 5000 times, and then an image was formed in the same manner as described above in an environment of 25 ° C., 50%, 30 ° C., and 85%. However, the image was thickly blurred under an environment of 25 ° C. and 50% RH. In addition, image flow occurred under an environment of 30 ° C. and 90% RH.

  As described above, when a static or latent image by photocharge charging is performed on a conductive support of the present invention using at least a photosensitive layer composed of a photosensitive layer and a photocharged charge layer, conventional discharge charging can be performed. It is possible to provide an image forming apparatus in which there is no deterioration of the photosensitive member and image blur and image flow are less likely to occur than when it is used.

(Example 8)
Using a cylindrical nickel belt having a thickness of 30 μm, a circumferential length of 180 mm, and a belt width of 340 mm prepared by electroforming a conductive support, an undercoat layer having the same composition and thickness as in Example 1, and charge generation An endless belt-like photoreceptor was prepared by providing a layer, a charge transport layer, and a photocharge charge layer.
An image was formed on this photoreceptor using the image forming apparatus shown in FIG. At that time, the endless belt photoreceptor was driven and supported by two rollers having a diameter of 25 mm and rotated at a speed of 100 mm / s. The image exposure means (2) uses an LED having a wavelength region of 645 nm, a silicon rubber roller having a diameter of 16 mm and an electric resistance of 10 ⁴ Ω · cm is brought into contact with the voltage application member (3), and a voltage of −500 V is applied in the accompanying state. The charging potential was measured.
V (OFF), V (ON), and ΔV were −200V, −450V, and −250V, respectively.
The endless belt-like photoreceptor of Example 8 can form an electrostatic charge latent image having sufficient electrostatic contrast for development in electrophotography.

The developing means (4) performed regular development using a two-component developer composed of a positively charged toner and a carrier. The transfer means (5) applied a negative voltage to the conductive roller to transfer the toner image to paper. The cleaning means (6) used a fur brush in order to reduce wear on the surface of the photoreceptor. As the charge eliminating means (7), a halogen lamp with a filter for cutting light in a wavelength range shorter than 700 nm was used. The potential after exposure with light of 700 nm or longer was 0V.
The photoreceptor (1), the two drive rollers, and the voltage application roller (3) are integrated into a unit that can be detached from the electrophotographic apparatus.
When an image was formed using such an apparatus, a clear image was obtained as in Example 1.

Example 9
A photoconductor for charging and charging was prepared and evaluated in the same manner as in Example 1 except that a photocharged charge layer having a dry film thickness of 1 μm was provided on the surface of the photosensitive layer using the following photocharged charge layer coating solution.

(Photocharged charge layer coating solution)
3 parts by weight of the bisazo pigment of the structural formula (2) 3 parts by weight of the charge transport material of the structural formula (3) 1 part by weight of bisphenol Z-type polycarbonate (viscosity average molecular weight 50,000) 2 parts by weight of alumina (average primary particle size: 0) .3 μm, “AA03” manufactured by Sumitomo Chemical)
Tetrahydrofuran 100 parts by weight Cyclohexanone 40 parts by weight

V (OFF), V (ON), and ΔV were −200 V, −400 V, and ΔV = −200 V, respectively.
Further, when a halogen lamp obtained by applying a filter that cuts light in a wavelength region shorter than 700 nm to a photosensitive member that is charged by lighting an LED is exposed to light longer than 700 nm, the potential of the exposed portion is 0 V. became.
When this photoreceptor was used to form an image in the same manner as in Example 1, a clear image was obtained.

The photoreceptor was subjected to a repeated forced fatigue test only for charging and exposure in the same manner as in Example 1, followed by the same method as the initial image formation in a temperature and humidity environment of 25 ° C., 50%, 30 ° C., and 85%. When an image was formed, a clear dot image similar to the initial stage without image blur and image flow was obtained under any environment.
Further, 10,000 continuous images were formed on the photoconductor of Example 1 and the photoconductor of Example 9 using the image forming apparatus shown in FIG. In the photoconductor of Example 1, slight streak-like scratches occurred on the surface of the photoconductor after forming 10,000 images, and slight streak-like image defects occurred in the output image. On the other hand, in the photoreceptor of Example 9, no scratches or the like were observed on the surface of the photoreceptor, and no defect was observed in the image after 10,000 sheets.

(Example 10)
<Formation of undercoat layer>
An undercoat layer coating solution having the following composition was applied on an aluminum cylindrical tube having an outer diameter of 100 mmφ by an immersion method so that the film thickness after drying was 3.5 μm, thereby forming an undercoat layer.

(Coating liquid for undercoat layer)
Alkyd resin (Beccosol 1307-60-EL: Dainippon Ink and Chemicals) 3 parts by weight Melamine resin (Super Becamine G-821-60: Dainippon Ink and Chemicals) 2 parts by weight Titanium oxide (CR-EL: Ishihara Sangyo) 20 parts by weight Methyl ethyl ketone 100 parts by weight

<Formation of charge generation layer>
On this undercoat layer, the following charge generation layer coating solution was dip-coated and dried by heating at 110 ° C. for 20 minutes to form a charge generation layer having a thickness of 0.3 μm.

(Coating solution for charge generation layer)
Bizazo pigment of the structural formula (6) 5 parts by weight Butyral resin (ESREC BMS: Sekisui Chemical) 2 parts by weight Cyclohexanone 60 parts by weight Methyl ethyl ketone 20 parts by weight

<Formation of charge transport layer>
Next, dip coating is performed on the charge generation layer using a coating liquid for a charge transport layer having the following composition, pre-dried at 80 ° C. for 10 minutes, and then heat-dried at 140 ° C. for 30 minutes to obtain a film thickness of 40 μm. A charge transport layer was formed.

(Coating liquid for charge transport layer)
Bisphenol Z-type polycarbonate (viscosity average molecular weight 50,000) 1 part by weight Charge transport material of the above structural formula (1) 1 part by weight Tetrahydrofuran 10 parts by weight

<Formation of photocharged charge layer>
On the charge transport layer thus prepared, a photocharged charge layer coating solution having the following composition was applied by spray coating, dried at room temperature, and then heated and dried at 160 ° C. for 20 minutes to charge the photocharge with a film thickness of 1 μm. A layer was formed to prepare a photoreceptor for charge charging.

(Photocharged charge layer coating solution)
3 parts by weight of titanyl phthalocyanine pigment (XD spectrum is shown in FIG. 10)
Charge transport material of the above structural formula (3) 3 parts by weight Bisphenol Z-type polycarbonate (viscosity average molecular weight 50,000) 1 part by weight Tetrahydrofuran 100 parts by weight Cyclohexanone 40 parts by weight

<Evaluation>
The charge generation layer coating solution and the photocharge charge layer coating solution prepared as described above are each coated and dried on a quartz glass substrate under the same conditions as the photoconductor, and the respective absorption spectra are obtained by using a commercially available spectrophotometer. The absorption spectrum was measured with a photometer (Hitachi: UV-3100). As a result, the absorption spectrum of the photocharged charge layer almost coincided with the absorption spectrum of CGM C shown in FIG. 8, and the maximum absorption peak wavelength was 800 nm. Further, the absorption spectrum of the charge generation layer almost coincided with the absorption spectrum of CGM A shown in FIG. 8, and the maximum absorption peak wavelength was 583 nm. Further, the transmittance at 780 nm of the photocharged charge layer was 10%.

FIG. 7 is the same as in Example 1 except that the photocharge charging characteristics of the photoconductor produced in this way is used as an exposure light source and LD light in a wavelength region of 780 nm deflected by a polygon mirror is used, and a 565 nm LED is used as a charge eliminating member. Measurement was performed as follows using the charging characteristic measuring apparatus shown in FIG.
That is, the photoconductor (1) rotating at a speed of 200 mm / s is exposed to LD light corresponding to (20) in the wavelength region of 780 nm through a polygon mirror, and silicon having a diameter of 16 mm and an electric resistance of 10 ⁴ Ω · cm. A voltage application member (3) made of a rubber roller was brought into contact, a voltage of −500 V was applied in the accompanying state, and the charging potential was measured in the same manner as in Example 1.
V (OFF) was −180V, V (ON) was −400V, and electrostatic contrast ΔV was −220V.
When the photosensitive member charged as described above was exposed to 565 nm LED light, the charged potential was attenuated, and the potentials of the exposed and non-exposed portions were both -10V.

Next, using this photoreceptor, an image was formed by an image forming apparatus using a process cartridge shown in FIG. The image forming method will be described below.
The photosensitive body (1) rotating at a linear speed of 100 mm / s is exposed to a 780 nm wavelength region of LD light through a polygon mirror, and a 600 dpi dot image is exposed to a volume resistance on a stainless steel shaft having a diameter of 8 mm as a voltage application member. Using a conductive voltage application roller (3) provided with a conductive urethane elastic layer with a rate of about 10 ⁴ Ω · cm, contact the surface of the photoreceptor (1) and apply a voltage of −500 V to cause electrostatic latent An image was formed.

As the developing means (4), a two-component developer composed of a positively charged toner and a magnetic carrier was used, and normal development was performed with a developing bias set to -200V. As a transfer means, a conductive transfer roller was used, and a negative voltage was applied to the roller to transfer the toner image onto paper. The toner image was fixed by a heat fixing device, and the surface of the photosensitive member was cleaned using fur brush cleaning as a cleaning means (6). When an image was formed under the above conditions, a clear image with no image blur, a uniform halftone part, and no roughness was obtained.
Further, residual charges on the photosensitive member were removed by overall exposure with 565 nm LED light. The potential on the surface of the photoreceptor after static elimination was -10V.

Next, the following forced fatigue test was conducted in order to investigate the deterioration of the photoreceptor when the charging method of the present invention was repeated.
The photoreceptor was subjected to 5000 repetition tests of 780 nm LD light irradiation, −500 V voltage application and 565 nm LED light overall exposure, and then in a temperature and humidity environment of 25 ° C., 50%, 30 ° C., and 85%. When an image was created by the same method as the initial image formation, a clear dot image similar to the initial one with no image blur or image flow was obtained.

(Example 11)
Except that the titanyl phthalocyanine used in Example 10 was changed to titanyl phthalocyanine having an XD spectrum in FIG. 11 (a titanyl phthalocyanine having a peak at a minimum angle of 7.5 degrees and a maximum peak at 27.2 degrees), A photoconductor was prepared and evaluated in the same manner as in Example 10. V (OFF) was -200V, V (ON) was -350V, and electrostatic contrast ΔV was -150V.
When a 565 nm LED light was exposed to the photosensitive member charged by turning on the LD, the charged potential was attenuated, and the potential of the exposed portion became −10V.

  Further, when image formation was performed in the same manner as in Example 1 using the image forming apparatus using the process cartridge shown in FIG. 6, there was no image blur, and the halftone portion was uniform and a clear image with no feeling of roughness was obtained. . The image contrast was slightly inferior to the image of Example 10.

Example 12
A photoconductor was prepared and evaluated in the same manner as in Example 10 except that the titanyl phthalocyanine used in Example 10 was changed to titanyl phthalocyanine having an XD spectrum in FIG. 12 (titanyl phthalocyanine having a maximum peak at 26.3 degrees). Was done.
As in the case of Example 10, the charging potential when a voltage of −500 V was applied was measured. V (OFF) was −180V, V (ON) was −280V, and electrostatic contrast ΔV was −100V. When a 565 nm LED light was exposed to the photosensitive member charged by turning on the LD, the charged potential was attenuated, and the potential of the exposed portion became −10V.

  Further, when the image forming apparatus using the process cartridge shown in FIG. 6 was used to form an image in the same manner as in Example 1, there was no image blur and an image having a slightly lower image density than that of Example 10 was obtained. It was.

(Example 13)
In Example 10, a photoconductor was prepared and evaluated in the same manner as in Example 10 except that the adhesion layer of the photocharged charge layer was changed so that the transmittance at 780 nm of the photocharged charge layer was 20%. .
As in the case of Example 10, the charging potential when a voltage of −500 V was applied was measured.
V (OFF) was −180V, V (ON) was −380V, and electrostatic contrast ΔV was −200V.

When a 565 nm LED light was exposed to the photosensitive member charged by turning on the LD, the charged potential was attenuated, and the potential of the exposed portion became −10V.
Further, when image formation was performed in the same manner as in Example 1 using the image forming apparatus using the process cartridge shown in FIG. 6, there was no image blur, and the halftone portion was uniform and a clear image with no feeling of roughness was obtained. .

(Example 14)
In Example 10, a photoconductor was prepared and evaluated in the same manner as in Example 10 except that the amount of adhesion of the photocharged charge layer was changed so that the transmittance at 780 nm of the photocharged charge layer was 30%. .
V (OFF) was −150V, V (ON) was −300V, and electrostatic contrast ΔV was −150V.
When a 565 nm LED light was exposed to the photosensitive member charged by turning on the LD, the charged potential was attenuated and the potential of the exposed portion became −20V.

  Further, when image formation was performed in the same manner as in Example 1 using the image forming apparatus using the process cartridge shown in FIG. 6, there was no image blur and an image having a slightly lower image density was obtained compared to Example 10. .

(Example 15)
In Example 14, a photoconductor was prepared and evaluated in the same manner as in Example 14 except that the charge generation material used for the charge generation layer was changed to that of the following structural formula (8).

The absorption spectrum of the charge generation layer corresponds to CGM B in FIG. 9, and has an absorption at a charging exposure wavelength of 780 nm.
As in the case of Example 14, the charging potential when a voltage of −500 V was applied was measured. V (OFF) was −180V, V (ON) was −280V, and electrostatic contrast ΔV was −100V.

When a 565 nm LED light was exposed to the photosensitive member charged by turning on the LD, the charged potential was attenuated and the potential of the exposed portion became −40V.
Furthermore, when image formation was performed in the same manner as in Example 1 with the image forming apparatus using the process cartridge shown in FIG. 6, there was no image blur and an image with a considerably lower image density was obtained compared to Example 14.

(Example 16)
The same undercoat layer, charge generation layer, and charge transport layer as in Example 1 were produced on an aluminum cylindrical tube having an outer diameter of 100 mmφ. Next, a photocharged charge layer having a dry film thickness of 1 μm was formed in the same manner as in Example 1 except that the following composition liquid was used on the charge transport layer to prepare a photoreceptor.

(Photocharged charge layer coating solution)
3 parts by weight of the bisazo pigment of the structural formula (2) 3 parts by weight of the polymer charge transporting material of the following structural formula (9) (weight average molecular weight: about 135,000)
Tetrahydrofuran 100 parts by weight Cyclohexanone 40 parts by weight

When this photoreceptor was used and an image was formed under the same conditions using the same image forming apparatus as in Example 1, a clear image without image blur was obtained.
Further, as in Example 9, when 10,000 continuous images were formed, no scratches were observed on the surface of the photoreceptor, and no defects were observed in the image after 10,000 sheets.

(Example 17)
A photoconductor was prepared in the same manner as in Example 16 except that the polymer charge transport material of the following structural formula (10) (weight average molecular weight: about 130,000) was used instead of the polymer charge transport material of Example 16.
When this photoreceptor was used and an image was formed under the same conditions using the same image forming apparatus as in Example 1, a clear image without image blur was obtained.
Further, as in Example 9, when 10,000 continuous images were formed, no scratches were observed on the surface of the photoreceptor, and no defects were observed in the image after 10,000 sheets.

(Example 18)
A photoconductor was prepared and evaluated in the same manner as in Example 17 except that the photocharge charging layer of Example 17 was formed as follows.
For the photocharged charge layer, the following photocharged charge layer coating solution was applied to the surface of the charge transport layer by spray coating, followed by heating and drying at 150 ° C. for 30 minutes to form a cured film of about 1 μm.

(Photocharged charge layer coating solution)
Bisazo pigment of structural formula (2) 1.5 parts by weight Methyl methacrylate-styrene-n-butyl methacrylate copolymer resin (average molecular weight: 15000, composition ratio: 20/30/30 (weight ratio)) 0.06 Part by weight 1,4-butanediol dimethacrylate 0.5 part by weight Charge transporting compound of the following structural formula (11) 1 part by weight Benzoyl peroxide 0.01 part by weight Tetrahydrofuran 50 parts by weight Cyclohexanone 15 parts by weight

When this photoreceptor was used and an image was formed under the same conditions using the same image forming apparatus as in Example 1, a clear image without image blur was obtained.
Further, as in Example 9, when 10,000 continuous images were formed, no scratches were observed on the surface of the photoreceptor, and no defects were observed in the image after 10,000 sheets.

  Since the electrophotographic photosensitive member of the present invention does not generate abnormal images even after repeated use and has high durability and high reliability, it can be used as an electrophotographic image forming apparatus such as a copying machine, a printer, and a facsimile machine. Is expensive.

It is a figure which shows the basic layer structure of the electrophotographic photoreceptor of this invention. It is a figure which shows the principle of charging and latent image formation in the electrophotographic photosensitive member of the present invention. It is a figure which shows the layer structure of the example of the electrophotographic photoreceptor of this invention which has a lamination type photosensitive layer. 1 is a diagram illustrating an example of a configuration of an image forming apparatus of the present invention. 1 is a diagram illustrating an example of an image forming apparatus of the present invention when an endless belt-like photoconductor is used. It is a figure which shows the example of the process cartridge of this invention. It is a figure which shows the measuring apparatus for measuring the charging characteristic of a photoconductor. It is the figure which showed the relationship between the light source wavelength for image exposure, and the absorption spectrum of a charge generation material. It is the figure which contrasted the absorption spectrum of three types of charge generation substances. 2 is a diagram showing an XD spectrum of titanyl phthalocyanine used in Example 1. FIG. 6 is a diagram showing an XD spectrum of titanyl phthalocyanine used in Example 11. FIG. 6 is a diagram showing an XD spectrum of titanyl phthalocyanine used in Example 12. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Image exposure means 3 Voltage application means, voltage application roller, voltage application member 4 Developing means 5 Transfer means 6 Cleaning means 7 Static elimination exposure means, static elimination means 8 Transfer paper 9a Drive roller 9b Driven roller 11 Conductive support 12 Photosensitive layer 12a Charge generation layer 12b Charge transport layer 13 Photocharge charge layer 14 Undercoat layer 15 Toner transport coil 16 Developer set case 17 Doctor blade 18 Transport screw 19 Development sleeve 20 LED light source 21 Static elimination roller, neutralization member 22 Surface potential meter

Claims (25)

At least the step of performing image exposure on the photoconductor and at the same time as or after the image exposure, a voltage is applied to the photoconductor through a conductive voltage applying member in contact with the photoconductor to apply the voltage to the photoconductor. An electrophotographic photosensitive member used in an image forming method having a step of forming an electrostatic charge latent image having the same polarity as that of the electrophotographic photosensitive member, wherein the electrophotographic photosensitive member generates a charge on at least the photosensitive layer and at least the image exposure on the conductive support. A photocharge charge layer containing a charge generation material and a charge transport material , and the photocharge charge layer is disposed on the surface of the photoreceptor, and the charge generation material contained in the photosensitive layer is formed in the photocharge charge layer. An electrophotographic photosensitive member having a maximum absorption wavelength different from the contained charge generating substance . The electrophotographic photosensitive member according to claim 1, wherein the charge generating material contained in the photocharged charge layer is an organic pigment. The charge generation material contained in the photosensitive layer is an organic pigment different from the organic pigment contained in the photocharge charging layer, and the maximum absorption wavelength of the organic pigment used in the photocharge charging layer and the photosensitive layer The electrophotographic photosensitive member according to claim 2, wherein the maximum absorption wavelength of the organic pigment used in the step is 200 nm or more . The electrophotographic photosensitive member according to claim 2 or 3 , wherein the organic pigment contained in the photocharge charging layer is an azo pigment. The electrophotographic photoreceptor according to claim 4 , wherein the azo pigment is an azo pigment represented by the following general formula (I).

[Wherein, Cp ₁ and Cp ₂ represent coupler residues. R ₂₀₁ and R ₂₀₂ each represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or a cyano group, and may be the same or different. The Cp ₁ and Cp ₂ are represented by the following general formula (II)

(In the formula, R ₂₀₃ represents a hydrogen atom, an alkyl group, or an aryl group. R ₂₀₄ , R ₂₀₅ , R ₂₀₆ , R ₂₀₇ , and R ₂₀₈ are a hydrogen atom, a nitro group, a cyano group, a halogen atom, and trifluoro, respectively. M represents a methyl group, an alkyl group, an alkoxy group, a dialkylamino group, or a hydroxyl group, which may be the same or different, and Z constitutes a substituted or unsubstituted aromatic carbocyclic ring or a substituted or unsubstituted aromatic heterocyclic ring. Represents a group of atoms necessary for. ] 6. The electrophotographic photosensitive member according to claim 5 , wherein Cp1 and Cp2 of the azo pigment are different from each other. The electrophotographic photosensitive member according to claim 2 or 3 , wherein the organic pigment contained in the photocharged charge layer is titanyl phthalocyanine. The titanyl phthalocyanine is 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 1.542１．５) of CuKα. The electrophotographic photosensitive member according to claim 7 . The titanyl phthalocyanine is mainly used at 9.4 °, 9.6 °, and 24.0 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray of CuKα (wavelength 1.542Å). A peak at 7.3 ° as the lowest diffraction peak, and no peak between the 7.3 ° peak and the 9.4 ° peak, and The electrophotographic photosensitive member according to claim 8 , wherein the electrophotographic photosensitive member has no peak at 26.3 °. The electrophotographic photosensitive member according to claim 1, wherein the charge transport material is a hole transport material. The electrophotographic photosensitive member according to claim 10, wherein the hole transport material is a compound having at least a triarylamine structure. The electrophotographic photosensitive member according to claim 1, wherein the charge transporting substance is a polymer charge transporting substance. The electrophotographic photosensitive member according to claim 12, wherein the polymer charge transporting material is a hole transporting material. The electrophotographic photosensitive member according to claim 12, wherein the polymer charge transporting material has a crosslinked structure. The electrophotographic photosensitive member according to any one of claims 1 to 14, characterized in that the filler is contained in the light charge storage layer. The electrophotographic photosensitive member according to any one of claims 1 to 15, wherein the photosensitive layer is characterized by comprising at least a charge generation layer and a charge transport layer. The electrophotographic photosensitive member according to any one of claims 1-16, wherein the conductive support is an endless belt shape. A voltage is applied to the photoconductor through at least a photoconductor and an image exposure unit that performs image exposure on the photoconductor, and a conductive voltage applying member that is in contact with the photoconductor simultaneously with or after the image exposure. An electrophotographic photosensitive member according to any one of claims 1 to 17 , wherein the photosensitive member comprises a voltage applying unit for forming an electrostatic charge latent image having the same polarity as the applied voltage on the surface of the photosensitive member. An image forming apparatus. A voltage is applied to the photoconductor through at least a photoconductor and an image exposure unit that performs image exposure on the photoconductor, and a conductive voltage applying member that is in contact with the photoconductor simultaneously with or after the image exposure. In the image forming apparatus, the image forming apparatus includes a voltage applying unit for forming an electrostatic latent image having the same polarity as the applied voltage on the surface of the photoconductor, and an exposure unit for removing static electricity on the photoconductor. image forming apparatus, wherein the body is an electrophotographic photosensitive member according to any one of claims 1 to 17. The image forming apparatus according to claim 18 or 19, characterized by using the light source of the image 400nm or more wavelength as an exposure unit. 21. The image forming apparatus according to claim 20 , wherein a light charge charging layer absorbs 80% or more of light used in the image exposure unit. The image forming apparatus according to any one of claims 18 to 21 , wherein the wavelength of the light used for the image exposure means is light in a region not absorbed by the charge generating material used for the photosensitive layer. The image forming apparatus according to any one of claims 18 to 22 , wherein the static elimination light from the static elimination exposure means for removing the electrostatic charge on the photosensitive member is transmitted through the photocharged charge layer by 30% or more. . The image formation according to any one of claims 18 to 23 , wherein the photocharge charging layer of the photoconductor has a positive charge transport function, and a negative voltage is applied to the voltage application member. apparatus. A process cartridge in which a photosensitive member and at least one selected from an image exposing unit, a voltage applying unit, a developing unit, a cleaning unit, a charge eliminating unit, and a transfer unit are integrated, and are detachably provided in an image forming apparatus main body. A process cartridge, wherein the photoconductor is the electrophotographic photoconductor according to any one of claims 1 to 17 .

Images