Ricoh Company, Ltd.

Tsuyoshi Imamura

Kyohta Koetsuka

Noriyuki Kamiya

Yoshiyuki Takano

Sumio Kamoi

Mieko Terashima

Hiroya Abe

Mieko Kakegawa

Masayuki Ohsawa

Hideo Yoshizawa

Makoto Nakamura

Kazuhisa Sudo

Tadaaki Hattori

Takashi Innami

Kenji Narita

Kenichi Ishiguro

Hideki Kimura

Masaki Watanabe

Masayuki Yamane

Kiyonori Tsuda

Shinji Tamaki

Shunji Katoh

Katsumi Masuda

Shigeharu Nakamura

Kiyotaka Sakai

Kyota Koetuka

Shinichi Kawahara

Kazuyuki Sugihara

Junichi Terai

Takahiro Yasunaga

Takeo Araki

Satoshi Terashima

Hiroyuki Nagashima

Kenzo Tatsumi

Mikio Ishibashi

Tokuya Ohjimi

Kyoichi Ashikawa

Toshihiro Atsumi

Masayuki Takeshita

Sumio Kamio

Kyota Koetsuka

Fumio Okuya

Hisatsugu Nagano

Yasuhiro Hujimori

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 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 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

The long magnet includes a magnet block made of a mixture of rare earth magnetic powder, thermoplastic resin particles, fluidity additive, pigment, wax and charge control agent, and a reinforcing member to reinforce the magnet block. At least part of the reinforcing member is arranged inside of the magnet block.

Long magnet, production method thereof, magnet roller and image forming device

A developer-carrying member to transport a developer having a carrier to a developing area facing an image carrying member in an image forming apparatus includes a sleeve. The sleeve carries the developer. The surface of the sleeve has a maximum roughness Rmax of one-sixth or greater than a particle diameter of the carrier, and a surface index of 1.5 or greater. The surface index is expressed by the equation of 'surface index=Rmax/(L&#x2212;LL),' in which LL is a measurement-range length selected from a roughness profile of the surface of the sleeve, Lis a total surface distance of the developer-carrying member in the measurement-range length LL, and Rmax is a maximum roughness of the sleeve surface, defined by a difference between a maximum roughness value and a minimum roughness value on a roughness profile of the surface of the sleeve.

Developer-carrying member having improved transportability, a developing unit, a process cartridge and an image forming apparatus

A development magnet roller for use in a development roller of an electrophotographic image forming apparatus is provided. The development magnet roller has a development pole to form a magnetic field causing a developer born on a surface of the development roller including the development magnet roller to rise in a form of a series of ears in a development area of the image forming apparatus where the development roller opposes an image bearing member, and in a magnetic flux density distribution in a normal line direction of the development pole, a peak magnetic flux density is 120 mT or greater, a zero gauss region width is 70&#xb0; or greater, and a half-value region width is 40&#xb0; or smaller.

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

An image forming apparatus includes an image forming mechanism and an image bearing member. The image forming mechanism is configured to form an image. The image bearing mechanism is detachably provided to the image forming apparatus. The image bearing mechanism includes an image bearing member configured to bear the image formed by the image forming mechanism, and a through shaft configured to support the image bearing member.

Image forming apparatus having a detachable cartridge including a photoconductive drum with axis shaft having a minimal rotational eccentricity, and a method of assembling the image forming apparatus

An image forming method and apparatus includes a development device in which two rotary shafts enclosed in respective separate chambers for spirally circulating the developer between the two chambers to supply the developer to a development roller. The development device is provided with an extended circulation enclosure having a fill opening communicating with the two chambers.

Method and apparatus for image forming capable of performing a stable image development

An image forming apparatus whereby it is possible to prevent unevenness in developing density caused by misalignment between the central axes of a driven side rotational coupling section for rotating a developer carrier and a drive side rotational coupling section for transmitting rotational drive force to the driven side rotational coupling section. The driven side rotational coupling section is fixed and the position thereof can be corrected slightly, by engaging the driven side rotational coupling section with a drive side rotational coupling section. A transmission gear is provided which meshes with the driven side rotational coupling section and transmits rotational drive force used to move the surface of the developer carrier. By means of an axle provided on at least one end of the transmission gear engaging with a positioning member on the main body of the image forming apparatus, the developer carrier is positioned in the main body of the image forming apparatus.

Image forming apparatus

A developing roller includes a developing sleeve having a nonmagnetic material, and a magnet roll provided inside the developing sleeve and formed by dispersing a magnetic powder in a polymer compound. A portion of the magnet roll corresponding to a developing pole of the magnet roll is equipped with a main-pole molded magnet whose magnetic force per unit of volume is greater than that of the magnet roll. A magnetic pole adjacent to the developing pole of the magnet roll downstream in the developer conveyance direction has a peak magnetic flux density on the developing sleeve greater than that of the developing pole, and has a half value width, which is the width of the magnetic pole at which a magnetic flux density of one-half the peak magnetic flux density is exhibited, greater than that of the developing pole.

Developing roller, developing apparatus, process cartridge, and image formation apparatus

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Sagamihara, Japan

Tsuyoshi Imamura