Sharp Kabushiki Kaisha Corporation

Mita Industrial Co., Ltd.

Mikio Kakui

Keisuke Sumida

Koichi Toriyama

Hideo Nakamori

Masayuki Sakamoto

Nariaki Muto

Maki Uchida

Tatsuhiro Morita

Rikiya Matsuo

Eiichi Miyamoto

Hisayuki Utsumi

Toru Nakazawa

Kazushige Morita

Akihiko Kawahara

Yukikatsu Imanaka

Masaaki Yokoyama

Sayaka Fujita

Tadashi Nakamura

Masanori Matsumoto

Hiroshi Sugimura

Takatsugu Obata

Satoshi Katayama

Sakae Saito

Yasuyuki Hanatani

Toshiyuki Fukami

Hirofumi Kawaguchi

Kotaro Fukushima

Yoshihide Shimoda

Tatsuo Maeda

Tadashi Sakuma

Hiroshi Shiomi

Yuji Tanaka

Susumu Murakami

Kuniaki Nakano

Masaki Hashimoto

Masashi Hirai

Kazunari Hamasaki

Katsuru Matsumoto

Nariaki Tanaka

Hiroaki Iwasaki

Tomomi Tanaka

Yasufumi Mizuta

Masashi Tanaka

Yoshiaki Masuda

Yoshio Inagaki

Tomoko Kanazawa

Makoto Kurokawa

Masanori Kinomoto

Ayako Yashima

Yuka Nakamura

Hiroko Ishibashi

Toshihiko Nishiguchi

Hisakazu Uegaito

Tomomi Nakamura

Hirotsugu Nishikawa

Kazuaki Ishikawa

Akiko Uchino

Ichiroh Fujii

Kazuo Matsumoto

An image forming apparatus includes a transfer belt unit which has an intermediate transfer belt for supporting toner images and primary transfer rollers for pressing the intermediate transfer belt against corresponding photoreceptor drums and moves the intermediate transfer belt along the surface of each photoreceptor drum to transfer the toner images to the intermediate transfer belt. The intermediate transfer belt is formed so as to be 30 &#x3bc;m to 50 &#x3bc;m in average thickness, each primary transfer roller is arranged at a position, along the moving direction of the intermediate transfer belt, which is deviated downstream with respect to the moving direction from the position where the intermediate transfer belt is in contact with the photoreceptor and which is projected toward the photoreceptor drum side so as to press the intermediate transfer belt against photoreceptor with a nip pressure ranging from 10 gf/cmto 40 gf/cm.

Transfer belt unit and image forming apparatus using the same

A method for producing a high-quality and low-cost laminate type electrophotographic photoreceptor having a coating film of uniform thickness with high efficiency is provided. In the electrophotographic photoreceptor having a laminated structure composed at least of two layers: a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance, the charge generating layer is formed by applying a coating solution for forming the charge generating layer onto the conductive support by an ink-jet coating method, and the charge transporting layer is formed by applying a coating solution for forming the charge transporting layer onto the charge generating layer by a roll coating method.

Method and apparatus for producing electrophotographic photoreceptor

An image forming apparatus having excellent cleaning property for an electrophotographic photoreceptor and capable of forming a high-quality, high-resolution image. A surface free energy (&#x3b3;) of a photoreceptor (), which is provided in the image forming apparatus (), is set to 20 to 35 mN/m. A volume average diameter of toner particles included in a developer stored in a developing unit () to develop an electrostatic latent image and form a toner image is set to 4-7 &#x3bc;m When &#x3b3; of the photoreceptor () is set to within a small range as the particle size of toner is reduced, even small-particle-size toner having increased specific surface area and largely affected by a inter-molecular force is limited in adhesion to the surface of the photoreceptor () to provide a good cleaning property and a high-quality image can be formed.

Image forming apparatus equipped with an electrographic photoreceptor having a surface with low surface free energy

An image forming apparatus having excellent chargeability, sensitivity and light responsivity of an electrophotographic photoconductor and capable of forming images of high quality and high resolution at a high speed in various circumstances, is provided. An electrophotographic photoconductor having a photosensitive layer containing the enamine compound represented by the following general formula (1), for example, the enamine compound represented by the following structural formula (1-1) as a charge transportation substance is mounted to an image forming apparatus and the volume average particle size of the toner contained in a developerhoused in a developing deviceis set to a size from 4 to 7 &#x3bc;m. 

Image forming apparatus

The object of the invention is to prevent interference fringes of images and allow precise measurement of the thickness of a layer by the optical interferometry by limiting the surface roughness of a conductive substrate. The surface roughness of the conductive substrate provided in an electrophotographic photoreceptor is such that the maximum peak-to-valley roughness height (Ry)=0.8 to 1.4 &#x3bc;m, the centerline average roughness (Ra)=0.10 to 0.15 &#x3bc;m, the ten-point average roughness (Rz)=0.7 to 1.3 &#x3bc;m, the average peak-to-peak distance (Sm)=5 to 30 &#x3bc;m, and the peak count Pc=60 to 100. In such an electrophotographic photoreceptor, light for exposure can be scattered to an appropriate extent, so that interference fringes can be prevented, and an interference pattern is formed during measurement of the thickness of the photosensitive layer by the optical interferometry so that the thickness of the layer can be measured with a high precision.

Electrophotographic photoreceptor and method for producing the same

In an electrophotographic photoreceptor including a conductive substrate and a photoreceptive layer formed on the conductive substrate wherein the photoreceptive layer charged uniformly is exposed to light corresponding to an image information to form an electrostatic latent image, the surface free energy (&#x3b3;) is determined to be at least 20 mN/m and at most 35 mN/m. The determination of &#x3b3; on the surface of the photoreceptorin the appropriate range makes it possible to suppress excessive adhesion of a toner to the surface of the photoreceptor, to suppress adhesion of foreign matters such as a paper powder and to make easy the separation thereof from the surface, which results in improving the cleanability of the photoreceptor. Since the image is formed with the photoreceptorhaving always the clean surface, the damage or the decrease in image quality does not occur over a long period of time.

Electrophotographic photoreceptor

A vibration insulating member fitting method includes the steps of: positioning and wrapping a sheet-like vibration insulating memberaround a shafthaving an air suction/exhaust portion; holding the sheet-like vibration insulating memberonto the shaftby air suction; and inserting the shaftthat sucks the sheet-like vibration insulating memberby the air suction into a hollow cylinderof a photosensitive drumto stop the air suction, causing the sheet-like vibration insulating memberto be tightly fitted onto the inner wall surface of the photosensitive drumby a restoring force of the sheet-like vibration insulating member. A vibration insulating member recovering method includes the steps of: inserting a shafthaving an air suction portion into a sheet-like vibration insulating memberfitted on an inner wall surface of a hollow cylinderof a photosensitive drum; starting air suction to suck and hold the sheet-like vibration insulating memberonto the shaft; detaching the sheet-like vibration insulating memberfrom the inner wall surface of the hollow cylinderof the photosensitive drum; and taking the shaftout of the hollow cylinderof the photosensitive drum, with the sheet-like vibration insulating memberbeing sucked and held on the shaft

VIBRATION INSULATING MEMBER FITTING METHOD, VIBRATION INSULATING MEMBER FITTING DEVICE, VIBRATION INSULATING MEMBER, VIBRATION INSULATING MEMBER RECOVERING METHOD, AND VIBRATION INSULATING MEMBER RECOVERING DEVICE

In the present invention, a filler element formed of a viscoelastic material with a compressive residual strain of 10% or less and a 25% compressive load of 1 kg/cm , having a specific shape, is mounted in a drum-shaped electrophotographic photosensitive body (photosensitive drum) . The filler element has a sufficient restoring force when deformed, so that it can be fixed to position without an adhesive. Also, the filler element is not moved by vibration or shock during repeated use, and good anti-vibration effect can be maintained.

Electrophotographic photosensitive body with hollow base and filler element, electrophotographic apparatus using same

The invention provides an electrophotographic photoreceptor, in which suppression of image defects and high sensitivity are compatible, and a method for production thereof. The invention also provides a coating fluid for forming a photosensitive layer and a method for production thereof, as well as an image-forming apparatus using said electrophoto-graphic photoreceptor. Briefly, the electrophoto-graphic photoreceptors may be constructed by forming an undercoating layer on a conductive support, and then forming a photosensitive layer on the undercoating layer. The undercoating layer contains titanium oxide particles in at least either needle shape or dendrite shape. The photosensitive layer contains an electric charge-generating material of which the primary particle size and cohesive particle size are in a range of 0.01 &mgr;m-10 &mgr;m. Accordingly, in the electrophotographic photoreceptors, it is possible to maintain high sensitivity and excellent durability and to form an image with no defect. The photosensitive layer in the electrophotographic photoreceptor has a multilayer structure consisting of a charge-generating layer and a charge-transporting layer. The charge-generating material is a phthalocyanine pigment.

Electrophotographic photoreceptor, process for production thereof, and image-forming apparatus using same

An organic electrophotographic receptor comprising at least an undercoating layer, an electric charge generating layer, and an electric charge transferring layer which are laminated in said order, wherein a coating fluid for forming said electric charge generating layer comprising an electric charge generating material, a binding resin, a silicon oil having a surface tension of 22 mN/m or less, and an organic solvent is stored inside a tank and a photosensitive base supported by a chucking device is dipped into said coating tank so as to form said electric charge generating layer.

Coating fluid for electric charge generating layer, organic electrophotographic receptor, and method to manufacturing the same

An electrophotographic photosensitive element is provided with a photosensitive layer containing a charge generating substance and a charge transport substance on a conductive support. X-type metal-free phthalocyanine and a disazo compound are contained as a charge generating substance. With the photosensitive element, sufficient sensitivity is achieved so as to cause virtually no problem, and it is possible to reduce possibility of causing an instable electrostatic property such as a reduction in a charge potential and an increase in a remained potential, even in the case of frequent reuse.

Electrophotographic photosensitive element and manufacturing method thereof

Highly sensitive and highly durable electrophotographic photoreceptors which generate faultless images can be produced by forming the under-coating layer on the conductive support and forming the photoreceptive layer on the layer. The under-coating layer contains dendritic titanium oxide. The under-coating layer contains the dendritic titanium oxide of which the surface is coated with (a) metal oxide(s) and/or (an) organic compound(s). The photoreceptive layer contains a phthalocyanine pigment, and the under-coating layer contains dendritic or needle-like titanium oxide of which the surface is coated with (a) metal oxide(s) and/or (an) organic compound(s). The photoreceptive layer contains a phthalocyanine pigment, and the under-coating layer contains dendritic or needle-like titanium oxide, of which the surface is coated with (a) metal oxide(s) and/or (an) organic compound(s), and an alcohol soluble polyamide resin.

Electrophotographic photoreceptor, process for production thereof, and

In accordance with the present invention, there is provided a phenanthrylenediamine derivative represented by the general formula (1). The derivative is excellent in the electric charge transferring capability, the compatibility with a binding resin and the stability, thereby providing a photosensitive material which is highly sensitive and excellent in the durability. ##STR1## �wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 each represent a halogen atom, an alkyl group, an alkoxy group or an aryl group; and a, b, c and d each represent an integer from 0 to 5!.

Phenanthrylenediamine derivative

The present invention provides a novel naphthylenediamine derivative which is superior in electric charge transferring capability, compatibility with binding resin and stability, and an electrophotosensitive material which has a higher sensitivity and an excellent durability. The above naphthylenediamine derivative is represented by the following general formula (1), and the electrophotosensitive material is formed by providing a photosensitive layer having this naphthylenediamine derivative as an electric charge transferring material on a conductive substrate. ##STR1## wherein R.sup.1 to R.sup.4, R.sup.5a to R.sup.5f and a to d are as defined.

Naphthylenediamine derivative and electrophotosensitive material using

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Nara, Japan

Mikio Kakui