Ricoh Company, Ltd.

Noriyuki Kamiya

Kyohta Koetsuka

Masayuki Ohsawa

Yoshiyuki Takano

Tsuyoshi Imamura

Hiroya Abe

Takashi Innami

Mieko Terashima

Sumio Kamoi

Tadaaki Hattori

Mieko Kakegawa

Toshio Kojima

Rei Suzuki

Takumi Terasaka

Masaki Watanabe

Shigeharu Nakamura

Makoto Nakamura

Nobuyuki Taguchi

Takamasa Ozeki

Yuuki Satoh

Toshiki Hayashi

Katsumi Masuda

Satoshi Terashima

Kenzo Tatsumi

Atsushi Ohta

Taisuke Tokuwaki

Takayuki Yoshii

Masashi Nakayama

Kyoichi Ashikawa

Kenji Narita

Toshihiro Atsumi

Yuusuke Arai

Takahiro Yasunaga

Yuki Moro

Soichiro Fukutomi

Masayuki Takeshita

Sumio Kamio

Kyota Koetsuka

A roller includes a cylindrical body having openings on both ends thereof and a press-fit member fitted in at least one of the openings of the cylindrical body with an outer circumferential face thereof in contact with an inner face of the cylindrical body. The outer circumferential face of the press-fit member is grooved obliquely to an axis of the cylindrical body, and the inner face of the cylindrical body is smooth at least in a portion that contacts the outer circumferential face of the press-fit member.

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

A magnet roller includes a roller-shaped body constructed of a magnetic field generating material, a first support rod provided to a first axial end of the body; and a second support rod provided to a second axial end of the body. At least one of the first and second support rods is constructed of a nonmagnetic material and includes a projecting part projecting outside the body from an end face of the body and a buried part united to the projecting part and positioned inside the body. The buried part includes a reduced-area portion smaller than a base end of the projecting part adjacent to the buried part in cross-sectional area perpendicular to an axial direction of the first and second support rods.

Magnet roller, developer bearer, development device, process cartridge, and image forming apparatus

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 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

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 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

A developer carrier includes a magnetic field generating device provided with a plurality of magnetic poles including an agent separating pole and a scooping pole, and a cylindrical hollow body accommodating therein the magnetic field generating device and rotated around an axis of the cylindrical hollow body. A half-value width of a magnetic flux density at both end portions of at least one magnetic pole of the agent separating pole and the scooping pole is formed to be identical to or narrower than a half-value width of the magnetic flux density at a central portion of the one magnetic pole.

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Yamato, Japan

Noriyuki Kamiya