Ricoh Company, Ltd.

Kyohta Koetsuka

Noriyuki Kamiya

Masayuki Ohsawa

Yoshiyuki Takano

Tsuyoshi Imamura

Hiroya Abe

Takashi Innami

Mieko Terashima

Tadaaki Hattori

Sumio Kamoi

Toshio Kojima

Mieko Kakegawa

Rei Suzuki

Takumi Terasaka

Takamasa Ozeki

Katsumi Masuda

Masaki Watanabe

Nobuyuki Taguchi

Shigeharu Nakamura

Yuji Suzuki

Yoshio Hattori

Hiroyuki Uenishi

Yuuki Satoh

Toshiki Hayashi

Satoshi Terashima

Makoto Nakamura

Kenzo Tatsumi

Takeroh Kurenuma

Tatsuya Tanaka

Akira Azami

Kiyotaka Sawada

Tsuyoshi Hashiyada

Jun Zhang

Kenji Narita

Kenichi Ishiguro

Takahiro Yasunaga

Yutaro Hoshino

Tomihiro Takahashi

Masayuki Takeshita

Sumio Kamio

Hidekazu Masuo

Wataru Kikuta

Mieko Kakegawa/Terashima

A polishing sheet includes a sheet including one side having a surface, a plurality of convex portions provided to project from the surface of the one side of the sheet, a plurality of first abrasive grains provided on an upper surface of each of the convex portions, and a plurality of second abrasive grains provided on the surface of the sheet. The second abrasive grains each have hardness higher than that of the first abrasive grains.

Polishing sheet, polishing tool and polishing method

A development device includes a developer container, a developer carrier, exposed partly from a casing, facing a latent image carrier in a development area, a magnetic field generator inside the developer carrier, having multiple magnetic poles including a conveyance pole to convey the developer downstream from the development area to a developer release portion, a developer agitator, and a developer regulator. A predetermined gap is kept between an outer surface of the developer carrier and an inner wall of the casing downstream from an opening of the casing, upstream from a developer release portion, in a direction in which the developer carrier rotates. Multiple recesses are formed in the outer surface of the developer carrier at a pitch in a circumferential direction shorter than half a width of a magnetic flux density of the developer conveyance pole in a direction perpendicular to an axial direction of the developer carrier.

Development device, and process cartridge and image forming apparatus incorporating same

A develop roller includes a magnet roller, and a develop sleeve containing the magnet roller and comprising a plurality of depressions in an elliptic shape regularly arranged with an interval in a longitudinal direction on a surface onto which developer is attracted by a magnetic force of the magnet roller, wherein the depressions are arranged such that a longitudinal direction of the depressions is intersected with the longitudinal direction of the develop sleeve, and a downstream side of the depressions are formed to be deeper than an upstream side in a rotary direction of the develop sleeve.

Develop roller, develop unit, process cartridge, and image forming apparatus

A development device including a developer container, a developer bearer, a magnetic field generator, a developer agitator to supply the developer to the developer bearer, and a developer regulator to adjust a layer thickness of the developer carried on the developer bearer. Multiple oval recesses oblique to the axial direction of the developer bearer are formed in the outer circumferential surface of the developer bearer and arranged in a circumferential direction and the axial direction thereof. An upstream inner wall of the recess in the rotational direction of the developer bearer applies a force to the developer as the developer bearer rotates, and an angle between a long axis of the recess and the axial direction is set so that the force applied by the upstream inner wall of the recess has a component in a direction substantially identical to the developer conveyance direction of the developer agitator.

Development device, process cartridge, and image forming apparatus including same having multiple recesses formed on a developer bearer

A magnet roller includes a magnetic field generator being columnar, a support element being columnar, coaxially provided at both ends of the magnetic field generator, and whose diameter is smaller than that of the magnetic field generator, a level element extending along an axis of the magnetic field generator with a distance from the axis, the distance larger than the diameter of the support element, and a high magnetic power element being a main magnetic pole provided on the level element, extending long along the axis of the magnetic field generator.

Magnet roller, developer holder element, develop unit, process cartridge, and image forming apparatus

A development roller includes a magnet roller and a rotatably supported development sleeve including inside thereof the magnet roller, the development sleeve is formed in a cylindrical shape and configured such that a shaft center of the cylindrical shape is inconsistent with a rotation axis of the development sleeve, the development sleeve includes an outer surface provided with many circular or elliptical depressions in a planar view, the depressions being regularly arranged at intervals, and a depth of the depression provided in a portion of the outer surface close to the rotation axis is larger than a depth of the depression provided in a portion of the outer surface far from the rotation axis.

Development roller, development device, process cartridge and image-forming apparatus

A magnetic particle carrying device includes a magnetic field generator and a hollow cylindrical structure. The magnetic field generator generates a magnetic field. The hollow cylindrical structure encases the magnetic field generator and attracts magnetic particles on an external surface of the hollow structure using the magnetic field. The external surface of the hollow cylindrical structure is provided with a plurality of elliptical depressions. The depressions include first type depressions and second type depressions. A long axis of a first type of elliptical depression is substantially extending in an axial direction of the hollow cylindrical structure, and a long axis of a second type of elliptical depression is substantially extending in a circumferential direction of the hollow cylindrical structure. The external surface of the hollow cylindrical structure has more elliptical depressions of the second type than elliptical depressions of the first type.

Magnetic particle carrying device, and developing unit, process cartridge, and image forming apparatus using the same, and surface treatment method of the same

A magnetic roller includes a solid-core roller having magnetic anisotropy in a direction orthogonal to a central axis thereof. The solid-core roller includes a body part, and shaft parts disposed on both ends of the body part, a concave groove provided in an outer circumference face of the body part to extend in an axial direction, and a magnetic block disposed in the concave groove, the magnetic block having a direction of magnetic anisotropy substantially orthogonal to a direction of the magnetic anisotropy of the magnetic roller.

Magnetic roller and manufacturing method thereof, developer carrier, development device, processing cartridge, and image forming apparatus

A developing unit includable in a process cartridge and in an image forming apparatus includes a developer bearing member including a magnetic field generator and a nonmagnetic hollow member, a developer container, an agitation/conveyance member, and a developer regulating member. The magnetic field generator has first and second magnetic poles to generate respective magnetic forces for removing the developer from the developer bearing member after the developer passes the development region. A developer-releasing region releases the developer from the developer bearing member using a release force. The developer is disposed higher than a surface of the developer in the developer storing chamber. A component of a magnetic flux density of the magnetic field generated by the magnetic field generator in a direction normal to the developer-releasing region is directed to a same direction as the first and second magnetic poles across the developer-releasing region without forming a local maximum point.

Developing unit, image forming apparatus incorporating same, and process cartridge including same

A development roller, including a development sleeve disposed near a photo conductive drum, a magnetic roller disposed in the development sleeve, and a supplying device configured to supply a developer including a toner and a magnetic carrier to the photo conductive drum uniformly, the development sleeve having an outer surface on which the developer including the toner and the magnetic carrier is adsorbed by a magnetic force of the magnetic roller.

Development roller including a development sleeve, surface treatment device that treats an outer surface of the development sleeve and wire member that roughens the outer surface of the development sleeve

A developing unit includable in a process cartridge and in an image forming apparatus includes a developer bearing member including a magnetic field generator and a nonmagnetic hollow member, a developer container, an agitation/conveyance member, a developer regulating member to regulate the thickness of a layer of the two-component developer. The magnetic field generator has first and second magnetic poles to generate respective magnetic forces for removing the developer from the developer bearing member after the developer passes the development region. The second magnetic pole generates a magnetic force to attract the developer to form a magnetic brush on the developer bearing member. The developer regulating member includes a magnetic member outwardly disposed on an exterior perimeter surface of the developer bearing member upstream from the developer regulating member, and one planar surface of the magnetic member faces the second magnetic pole across an effective development region.

Developer regulating member in a developing unit, process cartridge including same, and image forming apparatus incorporating same

An image forming device comprises a process cartridge. The process cartridge comprises a development roller. The development roller comprises a magnet roller and a developing sleeve. The magnet roller is fixed. The depressionseach having an oval shape are formed on the external surface of the developing sleeve. Both ends of the depressionswhich are adjacent with each other along the longitudinal direction of the developing sleeveare overlapped with each other and both ends of the depressionswhich are adjacent with each other along the circumferential direction of the developing sleeveare spaced with each other.

Development roller, development device, process cartridge and image forming device

A magnet roller includes a cylindrical roller body including a side surface in which a groove is formed, a magnet body which is disposed in the groove, and a magnetic metal member which is attached to a surface of the magnet body, which is remote from an opening of the groove.

Magnet roller and method for the same, magnetic particle-support member, development device, process cartridge, and image forming apparatus

A developing roller includes a developing sleeve and a magnet roller disposed within the developing sleeve to attract developer to an outer surface of the developing sleeve by magnetic force. The outer surface of the developing sleeve has a plurality of recesses of circular or elliptic shape in plan view regularly or irregularly arranged therein so as not to overlap.

Developing roller, developing device, process cartridge, and image forming apparatus

A magnetic field generating member with high stiffness and small size, an image development device, a process cartridge and an image forming apparatus including the magnetic field generating member as well as a manufacturing method of the magnetic field generating member are provided where the magnetic field generating member includes a main body, a groove provided in the main body, an interposition member configured to be fitted in the groove of the main body and including a concave portion and a magnetic member as a long magnetic compact fixed into the concave portion of the interposition member.

Magnetic field generating member and manufacturing method thereof, magnetic particle support body, image development device, process cartridge and image forming apparatus

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Fujisawa, Japan

Kyohta Koetsuka