Bridgestone Corporation

Konishiroku Photo Industry Co., Ltd.

Konica Corporation

Yoshio Takizawa

Koji Takagi

Takahiro Kawagoe

Satoru Ikeuchi

Hiroshi Kaneda

Osamu Sasaki

Naohiro Hirose

Akitoshi Matsubara

Kunio Akimoto

Ryuta Tanaka

Yoshitomo Masuda

Takeo Oshiba

Yuichiro Mori

Gaku Yakushiji

Tokuo Okada

Eiji Sawa

Hiroshi Harashima

Shinichi Suzuki

Hirofumi Hayata

Jiro Takahashi

Yoshihide Fujimaki

Kazuya Murata

Hideharu Daifuku

Norihiko Kaga

Hideyuki Niwa

Hajime Tamura

Taro Miyamoto

Kinya Suzuki

Shigeki Takeuchi

Hiroshi Yoshioka

Shu Inoue

Shohei Morikawa

Syozo Mitsui

Koichi Iwami

Kunio Sigeta

Naoto Abew

The present invention provides an improved elastic material which is free of roller abrasion when used in development rollers and overcomes disadvantages of the conventional silicone rollers of deterioration in the abrasion resistance, an elastic roller employing such elastic materials, and an electrophotographic apparatus and electrostatic recording apparatus incorporating such rollers. The elastic material satisfies a relationship represented by the following equation:log{()}&#x2266;&#x2212;0.0011()+0.1154()&#x2212;5.6where Tb is the tensile strength (N/mm), Eb is the tension fracture elongation (%) and Hd is the Asker C hardness (&#xb0;). Further, the present invention provides a novel developer carrier for use with an imaging apparatus and an imaging apparatus incorporating the developer carrier. The developer carrier includes an electrically conductive elastic layer and is arranged in contact with, or in the proximity of, an imaging body. In the developer carrier, the conductive elastic layer satisfies the equation:0.01&#x2266;&#x2266;2.0where S is the compressive permanent set (%), T is the thickness of the elastic layer (mm), and Hd is the Asker C hardness (&#xb0;).

Elastic roller

A developing roller supports a one-component developer on a surface thereof in the form of a thin layer, and is brought in contact with or in proximity to an image forming body in such a state, to supply the developer on a surface of the image forming body, thereby allowing a visible image to be formed on the surface of the image forming body. The developing roller includes: an elastic layer having an ionically conductivity whose surface is imparted with a resin component having a high resistivity. Thus, if R1 is a resistance of the roller in a stationary state and R2 is a resistance of the roller in a rotational state, a relationship of R1&gt;R2 is established. With this developing roller, it is possible to obtain a high quality image and a high gradient.

Developing roller and developing apparatus

A toner-carrying roller such as a developing roller having a surface gloss of 2 or above, with the surface gloss of the black glass standard plate having a reflective index of 1.567 (according to DIN 67 530) being 100. The toner-carrying roller provides high-quality images free of density variation and fogging owing to its surface characteristics specified by the surface gloss. In addition, it keeps its good performance without deterioration in image quality for a long period of use.

Gloss and image forming apparatus

A developing roller is adapted to carry a developer on its surface and come in contact with or close to a photoconductor drum having an electrostatic latent image borne on its surface whereby the developer is supplied to the drum to visualize the latent image. The developing roller includes a highly conductive shaft and an elastic layer with conductivity formed around the shaft. The elastic layer is surface treated so as to have a resin component which contains a urea resin and/or melamine resin. The roller satisfies log(R.sub.2 /R.sub.1).ltoreq.4.5 wherein the untreated roller has a resistance R.sub.1 and the roller with the resin component has a resistance R.sub.2. The developing roller does not contaminate the photoconductor drum and ensures that images of quality are reproduced without a density variation and background fog over a long time.

A developing roller (1) includes a highly conductive shaft (2) and a conductive elastic layer (3). When the developing roller carring a one-component developer thereon comes in contact with or in proximity to an image forming body, the developer is supplied from the roller to a surface of the image forming body, thereby forming a visible image on the image forming body surface. The elastic layer (3) has applied to its surface a resin component having an elongation at rupture of less than 10% as measured according to JIS K7113. The developing roller ensures that images of high quality are reproduced without a drop of image density over a long period of time.

Developing roller and apparatus

A developing roller (1) having a highly conductive shaft (2), an elastic layer (3) having conductivity around the shaft, and a conductive layer (4) on the elastic layer containing carbon black having an oil absorption of 30-80 ml/100 g and a specific surface area of 30-150 m.sup.2 /g. The developing roller carries a developer on its surface and comes in contact with or close to a photoconductor drum having an electrostatic latent image borne on its surface whereby the developer is supplied to the photoconductor drum to visualize the latent image. The developing roller has a low hardness, ensures intimate contact with the photoconductor drum, and is improved in electric conduction stability and anti-staining so that acceptable images can be consistently produced over a long term.

Developing roller employing an elastic layer between conductive shaft

A developing roller (1) having a thin layer of a developer (4) carried thereon and a drum (3) bearing an electrostatic latent image on its surface are rotated in close relationship, thereby feeding the developer (4) to the surface of the drum (3) for visualizing the electrostatic latent image thereon. The ionization potential of the developing roller (1) surface is adjusted to be below the ionization potential of the developer (4) surface when the developer is charged negative and above the ionization potential of the developer (4) surface when the developer is charged positive. The developer has an ionization potential of 4.5-5.5 eV. When using negatively charged developer, the development roller should preferably contain a lubricant or non-ionic surfactant and should preferably be made of a polyurethane containing a polyisocyanate so as to obtain the desired ionization potential.

Apparatus for developing electrostatic latent images using developing

An object, typically photoconductor drum is electrically charged by placing a contact charger member in abutment with the object to be charged and applying voltage between the contact charger member and the object. Charging is effected by properly controlling the capacitance of the contact charger member, the capacitance of the object, and the applied voltage. A sufficient charged potential is achieved through the application of a relatively low voltage, while preventing ozone generation.

Contact charging method and apparatus

A developing roller comprising a conductive layer formed around a shaft carries a non-magnetic one-component developer on its outer surface to form a thin film of the developer and contacts a photoconductor drum having an electrostatic latent image borne on its surface whereby the latent image is developed to form a toner image. In one embodiment, the surface of the conductive layer has a DIN 4776 core roughness depth Rk of 0.5-3.5 .mu.m in a circumferential direction of the roller, and the ratio of circumferential Rk to axial Rk is greater than 1.0. In another embodiment, the surface of the conductive layer is provided with microscopic ridges and recesses which are alternately disposed in a rotational direction to define wavy streaks having a longitudinal direction substantially aligned with an axial direction of the roller.

Developing roller, and method and apparatus for developing latent images

An electric charging member and electric charging apparatus are described, including the surface of the charging member being formed of a resin layer including a nylon copolymer containing at least 15% by weight of nylon 12 or a urethane-modified acrylic resin containing 5-80% by weight of an acrylic resin component.

Electric charging member and electric charging apparatus

A developing roller includes a metal shaft and a conductive resilient sleeve surrounding the shaft and made of a urethane elastomer containing carbon black with at least pH 5. The developing roller is mounted in an electrophotographic apparatus in combination with a latent image-bearing photoreceptor wherein development is carried out using a non-magnetic single-component toner.

An electrophotographic photoreceptor is disclosed. The photoreceptor comprises a conductive layer and provided thereon, a photoreceptor layer comprising a carrier generation layer containing 100 parts by weight of a polycyclic quinone compound and 0.01 to 100 parts by weight of at least one of compounds represented by the following Formulas (I) and (II): ##STR1##

Electrophotographic photoreceptor

An electrophotographic photoreceptors containing a bisstyryl compound represented by the following formula I is disclosed. ##STR1## R.sup.0 and/or R.sup.00 represent methyl group, and the rest of Rs represent hydrogen atom or an alkyl group having 1 to 4 carbon atoms; and Ar.sup.1 and Ar.sup.2 represent each an aromatic group.

Bisstyryl compound and the electrophotographic photoreceptors relating

A photoreceptor that has at least a subbing layer and a light-sensitive layer formed on an electro-conductive supports is disclosed. The improvement is that said subbing layer is formed of a copolymer comprising ethylene, vinyl acetate and an unsaturated carboxylic acid and/or vinyl alcohol.

Photoreceptor

This invention relates to a toner for development of electrostatic images to be used for development of electrostatic images formed in electrophotography, electrostatic printing, electrostatic recording, etc., and an image forming method by use thereof. The toner of the present invention uses a resin constituted mainly of a copolymer comprising a crystalline polymer block and an amorphous polymer block chemically bound together, the cyrstalline polymer block has a specific melting point, the amorphous polymer block has a specific glass transition point, the moduli of the toner has a value with a specific range, and therefore according to the present invention, a toner excellent in durability can be provided, which is capable of fixing sufficiently even at a low temperature and yet also good in off-set resistance within such a temperature range, further having excellent anti-blocking characteristic, flowability, charging characteristic, anti-filming characteristic, cleaning property, thus being capable of forming good visible images stably.

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Fussa, Japan

Yoshio Takizawa