Ricoh Company, Ltd.

Mieko Terashima

Kyohta Koetsuka

Noriyuki Kamiya

Yoshiyuki Takano

Hiroya Abe

Tsuyoshi Imamura

Masayuki Ohsawa

Tadaaki Hattori

Takashi Innami

Masaki Watanabe

Shigeharu Nakamura

Sumio Kamoi

Rei Suzuki

Satoshi Terashima

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

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 method of manufacturing a hollow body having an external surface randomly provided with a large number of depressions is provided. The method includes providing the large number of depressions on the external surface of the hollow body. A profile curve of the external surface in a circumferential direction is obtained while rotating the hollow body. A frequency analysis is performed on the obtained profile curve. A quality of the hollow body is judged by comparing a result of the frequency analysis with a predetermined judgment standard.

Method of manufacturing a hollow body used in an image forming apparatus

A magnetic roller includes a cylindrical magnetic field generation part (), a cylindrical support part () that contacts both of the edges of the magnetic field generation part (), further has a smaller diameter than the magnetic field generation part (), and which is installed upon a common axis thereof as an axis of the cylindrical support part (), and a depression part () that is installed upon an obverse surface of the cylindrical magnetic field generation part (), extends in a direction of the axis of the magnetic field generation part (), and wherein a lengthwise magnet formation is inserted. The cylindrical magnetic field generation part () is configured of a main body portion (), which is installed upon a central portion of the cylindrical magnetic field generation part (), and a reinforcing portion (), which is installed upon each of both ends, wherein the depression part () is installed across the main body portion () of the magnetic field generation part () overall, and the reinforcing portion () is installed between an end of the depression part () and an end of the support part.

Magnetic roller, developer carrier, developing device, process cartridge, and image forming apparatus

A developer holding member includes a magnetic field generating device and a hollow body including the magnetic field generating device thereinside, and attracting a developer to an external surface thereof with magnetic force of the magnetic field generating device. The external surface of the hollow body is randomly provided with a large number of depressions, and a peak intensity of a spectrum within a range of wavelengths not more than 1 mm, which is figured out by performing a frequency analysis using a profile curve in a circumferential direction of the external surface, is not more than 12.

Developer holding member, development device, process cartridge, image forming apparatus and method of manufacturing hollow body

A magnet compound material to be compression molded, said magnet compound material comprising a magnetic powder and a binder resin particles, wherein a ratio of Dv to Dn is in a range of 1.1 to 1.3, Dv and Dn of the binder resin particles denote the volume average particle diameter and the number average particle diameter, respectively.

Magnet compound material to be compression molded, a molded elongate magnetic, a magnet roller, a developing agent-carrying body, a developing apparatus and an image-forming apparatus

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Isehara, Japan

Mieko Terashima