Ricoh Company, Ltd.

Yu Wakabayashi

Manabu Nonaka

Yoshikuni Ishikawa

Toshiaki Takahashi

Kazunori Bannai

Hidehiko Fujiwara

Kohta Takenaka

Yuuki Shiga

Shohei Shinkawa

Yasuhide Fukushima

Ryohhei Ohya

Tetsuro Hirota

Toshihiro Shimada

Masashi Sato

Shun Kobayashi

Rie Ohtsuka

Shintaroh Yamada

Ryuta Kaneda

Aki Ikeda

Kaoru Shoji

Tetsutaro Oishi

A sheet conveying device includes a pair of rollers, a biasing member, a guide member, a biasing support, and a biasing force changer. The pair of rollers includes a first roller and a second roller disposed in contact with the first roller. The pair of rollers is configured to hold a sheet between the first roller and the second roller. The biasing member is configured to bias the first roller toward the second roller. The biasing support is configured to support the biasing member and has a guide target member configured to slide along the guide member to move the biasing support. The biasing force changer is configured to change a biasing force of the biasing member along with movement of the biasing support. The guide target member has a portion projecting into a sheet conveyance passage through which the sheet is conveyed by the pair of rollers.

Sheet conveying device and image forming apparatus incorporating the sheet conveying device

A sheet conveying device includes a pair of rollers including a first roller and a second roller to hold a sheet conveyed between the first and second rollers; a biasing member to bias the first roller toward the second roller; a biasing force changer to change a biasing force of the biasing member; control circuitry to, when a predetermined changing condition is met, cause the changer to change the biasing force and cause the rollers to convey the sheet; an operation detector to detect a changing operation of the changer; and a notification device to notify an abnormality of the changing operation when the operation detector detects the abnormality. When the operation detector detects the abnormality, the control circuitry performs sheet conveyance control to cause the rollers to convey the sheet without causing the changer to change the biasing force, regardless of whether the predetermined changing condition is met.

A sheet feeding device, which is included in an image forming apparatus, includes a sheet container to accommodate a recording medium, a sheet feeding body to press a surface of the recording medium in the sheet container and feed the recording medium in a sheet conveying direction, a pair of sheet position regulators to regulate a position of the recording medium in a sheet width direction perpendicular to the sheet conveying direction, and a load applier to contact the surface of the recording medium and apply a load to the recording medium at the surface. The recording medium is brought to move toward one of the pair of sheet position regulators while the recording medium is being fed. A lower face position in a standby state of the sheet feeding body is lower than a lower face position in a standby state of the load applier.

Sheet feeding device and image forming apparatus incorporating the sheet feeding device

A sheet size detector to detect a sheet size of a recording medium includes a movable member to move in a sheet size detection direction to a position corresponding to the sheet size, a magnetic flux detector including a coil disposed on a board face parallel to the sheet size detection direction to generate a magnetic flux in a direction perpendicular to the board face, and a target to oppose the board face and including a material to affect the magnetic flux. The target is different in configuration in the sheet size detection direction to change the magnetic flux in the direction perpendicular to the board face as the movable member moves. The magnetic flux detector outputs a signal corresponding to changes in magnetic flux in the direction perpendicular to the board face, and the signal corresponds to the position of the movable member.

Sheet size detector and image processing apparatus

A sheet containing device, which is included in a sheet feeder and an image forming apparatus, includes a first sheet container, a second sheet container disposed adjacent to the first sheet container, a transfer unit to transfer a bundle of sheets contained in the second sheet container to the first sheet container, a pair of side fences including a first side fence and a second side fence to regulate a position of the bundle of sheets in a width direction of the bundle of sheets loaded on the first sheet container, and a pressing unit mounted on the first side fence and pressing the bundle of sheets loaded on the first sheet container against the second side fence.

Sheet containing device, sheet feeder incorporating the sheet containing device, and image forming apparatus incorporating the sheet containing device

A sheet feeding device includes a sheet carrying unit and an attraction separation and conveyance device. The sheet carrying unit is configured to carry thereon a sheet stack. The attraction separation and conveyance device is configured to electrostatically attract the uppermost sheet of the sheet stack and separate and convey the uppermost sheet from the sheet stack, and is placed between the upstream end and the central position in a sheet conveying direction of the sheet stack located at a sheet carrying position and having a minimum sheet size compatible with the sheet feeding device.

Sheet feeding device and image forming apparatus incorporating same

A sheet feeding device includes a sheet carrying unit, an attraction separation device electrostatically attracting and separating an uppermost sheet from a sheet stack and including multiple rollers, an endless dielectric belt stretched over the multiple rollers, and an elastic member provided inside a loop of the belt to cause the endless dielectric belt to contact the uppermost sheet, a sheet conveying device, and a lifting and lowering device. The lifting and lowering device lifts the sheet stack to a lift position at which the uppermost sheet contacts with the attraction separation device, and the attraction separation device stands by for a predetermined time to attract the uppermost sheet and starts to convey the uppermost sheet after the predetermined time elapses in a state in which the sheet stack remains at the lift position.

A sheet conveying device includes an attractive separation unit and a contacting and separating device. The attractive separation unit includes an attraction belt arranged to face the upper surface of a sheet stack, two rollers that stretch the attraction belt taut, with the upstream-side roller in the sheet conveying direction supported to be movable in substantially upward and downward directions within a predetermined range with respect to the upper surface of the sheet stack, and a charging device which charges a surface of the attraction belt. The contacting and separating device swings the attractive separation unit to make the attraction belt come into contact with and separate from the sheet stack, with a fulcrum of the swing of the attractive separation unit set to a position upstream in the sheet conveying direction of the upstream-side roller in the sheet conveying direction.

Sheet conveying device and image forming apparatus

A fixing device includes a fixing member, a pressing member, a temperature detector, and a heater. The pressing member contacts an outer circumferential surface of the fixing member to form a fixing nip between the fixing member and the pressing member through which a recording medium bearing a toner image passes. The heater heats the fixing member to a predetermined temperature based on a detection result provided by the temperature detector. A circumferential distance A between the temperature detector and the heater along a circumference of the fixing member is defined by the following formula:&#xd7;(1+2)where v is a circumferential velocity of the fixing member rotating in a predetermined direction of rotation, Tis a response time of the temperature detector, and Tis a response time of the heater.

Fixing device, image forming apparatus incorporating same, and method of dimensioning fixing device

A charging brush unit includes a brush and a conductive holder. The brush includes a plurality of flexible conductive fibers. The plurality of flexible conductive fibers is supplied with a charging bias to generate electrical discharge between a top of the plurality of conductive fibers and a latent image carrier across a gap formed between the top of the plurality of conductive fibers and the latent image carrier. The gap is provided with an electrode. The electrode includes a plurality of openings opposing the top of the plurality of conductive fibers and is supplied with a bias different from the charging bias applied to the plurality of conductive fibers. The conductive holder holds the brush.

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Kanagawa-ken, Japan

Yu Wakabayashi