Ricoh Company, Ltd.

Hitachi Koki Co., Ltd.

Hitachi, Ltd.

Makoto Nakura

Naoto Ueda

Shingo Takai

Koichi Kudo

Satoshi Ueda

Junji Shirakawa

Akira Kobashi

Hiroshi Suzuki

Kenji Ishii

Tomoyasu Hirasawa

Susumu Tateyama

Hiromitsu Fujiya

Kenichi Takehara

Yutaka Shoji

Keisuke Ikeda

Keisuke Yuasa

Hiroaki Miyagawa

Yasuaki Toda

Takeshi Watanabe

Takuro Kamiya

Satoru Tao

Hirofumi Ohkushi

Shinji Kato

Akira Arimoto

Takeshi Mochizuki

Susumu Mikajiri

Masuo Kasai

Minoru Seino

Osamu Namikawa

Akira Terakado

Junichi Kawase

Kazutoshi Obara

Yoshinari Onuma

Minoru Ohshima

Shuichi Morio

Masaru Kawamoto

Yoshihiro Gunji

Shinya Tomita

Susumu Saitoh

Masanori Takayasu

A transfer device includes a rotatable image bearer configured to bear a toner image to be transferred to a recording medium, a first rotator, and a second rotator. The second rotator is configured to contact the first rotator via the rotatable image bearer to form a transfer nip in which the recording medium is sandwiched. The second rotator is rotatable with the image bearer. The transfer device satisfies a conditional expression (t+R)/(t+R)&#x3e;0.98, where trepresents a thickness of a thinnest recording medium, trepresents a thickness of a thickest recording medium, and R represents a radius of curvature of the transfer nip.

Transfer device and image forming apparatus incorporating same

A recording-material cooling device includes a first belt, a first cooling unit, and a second cooling unit. The first belt is disposed at a first face side of a recording material. The first cooling unit has a first heat absorbing surface to contact the first belt to absorb heat of the recording material. The second cooling unit has a second heat absorbing surface to directly or indirectly contact the recording material to absorb heat of the recording material. The second cooling unit is disposed at a second face side of the recording material. The first and second cooling units are offset from each other in a transport direction of the recording material. Each of the first and second surfaces has a shape in which an inner area protrudes beyond opposed ends in the transport direction. The first and second surfaces overlap each other in a direction crossing the transport direction.

Cooling device and image forming apparatus including same

An image forming apparatus includes an image forming unit forming an image on a first recording medium based on image data, a measurement unit being positioned in an immediate vicinity of the image forming unit, being arranged upstream of a sheet-conveyance path than the image forming unit, and measuring a size of the first recording medium, an expansion ratio calculation unit calculating an expansion ratio of the first recording medium based on a first size of the first recording medium obtained before the first recording medium is passed through the image forming unit and a second size of the first recording medium obtained after the first recording medium is passed through the image forming unit, and a correction unit correcting the image data used for forming another image on a second recording medium conveyed after the first recording medium based on the expansion ratio.

Image forming apparatus, image forming method, and computer-readable recording medium

An image forming apparatus includes an image forming unit that forms an image on a recording medium; a width detector that detects positions of side edges of the recording medium in a width direction, which is orthogonal to a conveying direction in which the recording medium is conveyed, at multiple detection positions along the conveying direction; a shape calculator that calculates angles between the conveying direction and straight lines each connecting the positions of the same side edge detected at the multiple detection positions and calculates a shape of the recording medium based on the angles; and a correction unit that corrects image data of the image to be formed by the image forming unit based on the calculated shape of the recording medium.

Image forming apparatus for calculating shape of recording medium based on angles between conveying direction and straight lines using upstream and downstream detectors

An image forming apparatus includes an image forming unit to form an image on a recording medium; an inverting transport unit to invert first and second surfaces of the recording medium, and front and rear ends of the recording medium to transport the inverted recording medium; a recording medium width measuring unit to measure an end position of the recording medium in a width direction orthogonal to a transporting direction of the recording medium at a measuring position having an approximately identical distance from one end of the recording medium in the transporting direction before and after the image is formed on the recording medium; and a correcting unit to correct an image to be formed on a subsequent recording medium based on a change in a shape of the recording medium computed based on a measured result from the recording medium width measuring unit.

Image forming apparatus for improving accuracy in alignment of an image to be printed on two surfaces of a recording medium by measuring a size of the recording medium

A sheet conveying apparatus includes a sheet conveying unit that conveys a sheet including a drive roller, a driven roller, and a rotary encoder provided on a rotational axle of one of the drive roller and the driven roller; a conveying amount measuring unit that measures a conveying amount of the sheet; a first detection unit positioned downstream of the sheet conveying unit, the first detection unit being positioned apart from the drive roller and the driven roller not to overlap with the drive roller and the driven roller in the conveying direction; a second detection unit positioned upstream of the sheet conveying unit; and a conveying distance calculation unit that calculates a conveying distance of the sheet based on the measured result by the conveying amount measuring unit and the detected results detected by the first detection unit and the second detection unit.

Sheet conveying apparatus, image forming apparatus, sheet conveying distance calculation apparatus and sheet length calculation apparatus

A sheet conveying apparatus includes a sheet conveying unit including a drive roller and a driven roller; a downstream detection unit and an upstream detection unit; a conveying amount measuring unit that measures a conveying amount of the sheet; and a conveying distance calculation unit that calculates a conveying distance of the sheet, wherein a distance between the downstream detection unit and the upstream detection unit or a perimeter of one of the drive roller and the driven roller is set such that an expected conveying distance calculated based on a set sheet length of an expected value of the sheet becomes a substantially integer multiple of a perimeter of the one of the drive roller and the driven roller.

Sheet conveying apparatus and image forming apparatus

A cooling device includes a cooling member to cool a recording material. The cooling member includes a cooling surface member, a heat exchanging member, and a fastening member. The cooling surface member has a cooling surface to directly or indirectly contact the recording material and absorb heat of the recording material to cool the recording material. The heat exchanging member is directly or indirectly joined to the cooling surface member to radiate heat absorbed by the cooling surface member directly or indirectly via a radiation member. The fastening member fastens the cooling surface member and the heat exchanging member to retain a joined state in which the cooling surface member and the heat exchanging member are directly or indirectly joined to each other. The cooling surface member and the heat exchanging member are separable from the joined state to a separated state without damaging the fastening member.

Cooling device and image forming apparatus incorporating same

An image forming apparatus includes an image carrier, a transfer unit to transfer the image onto a recording medium, a torque limit unit to transmit drive force to the transfer unit at a torque less than the torque for transmitting drive force, and drive the transfer unit to rotate at a circumferential velocity higher than that of the image carrier when the image carrier and the transfer unit are in contact with each other, and a drive unit to output drive force to drive the transfer unit such that the transfer unit rotates at a circumferential velocity lower than that of the image carrier when the image carrier and the transfer unit are separate from each other, and the transfer unit rotates at a circumferential velocity higher than that of the image carrier when the image carrier and the transfer unit are in contact with each other.

Image forming apparatus

A disclosed sheet carrying device includes a first carrying unit that includes a first rotary body, a first driving unit outputting a driving force at a first peripheral speed, a one-way clutch transmitting the driving force only in a sheet carrying direction, and a second rotary body driven by the first rotary body via the sheet; and a second carrying unit including a third rotary body rotating at a second peripheral speed being the first peripheral speed or more, a fourth rotary body carrying the sheet with the third rotary body, a second driving unit outputting a driving force for driving the fourth rotary body at a third peripheral speed being the second peripheral speed or more, and a torque limiter having a slip torque smaller than a sheet carrying torque and cutting off the driving force while the sheet is interposed between the third and fourth rotary bodies.

Sheet carrying device and image forming apparatus

A sheet conveying apparatus includes a sheet conveying unit that conveys a sheet; a conveying amount measuring unit that measures a conveying amount of the sheet conveyed by the sheet conveying unit; a first detection unit that detects the sheet downstream of the sheet conveying unit in a conveying direction of the sheet; a second detection unit that detects the sheet upstream of the sheet conveying unit in the conveying direction of the sheet; and a conveying distance calculation unit that calculates a conveying distance of the sheet based on the measured result by the conveying amount measuring unit and the detected results detected by the first detection unit and the second detection unit.

A sheet length measuring device includes a rotating body configured to rotate with a movement of a sheet in a conveying direction; a position detecting unit configured to detect leading and trailing ends of the sheet passing through a position of the rotating body; a measuring unit configured to measure a rotation amount of the rotating body and output an origin signal per one revolution of the rotating body; a storage unit configured to store changes of a sheet conveying amount with respect to respective rotation angles in one revolution of the rotating body; and a calculating unit configured to calculate a corrected length of the sheet from a value obtained from a rotation angle of the rotating body when the leading end of the sheet is detected and a value obtained from a rotation angle of the rotating body when the trailing end of the sheet is detected.

Sheet length measuring device and image forming apparatus

A gear drive apparatus includes a gear train including a plurality of gears, and a holding unit accommodating the gear train and a lubricant to be supplied to tooth flanks of each of the plurality of gears, the holding unit including an inlet opening from which the lubricant is poured. The lubricant from the inlet opening is supplied to an engagement area where two gears of the plurality of gears are engaged with each other, or to a tooth flank area of one of the two gears at an upstream part from the engagement area along a rotational direction of the one of the two gears.

Gear drive apparatus, driving device including gear drive apparatus, and image forming device including gear drive apparatus

A sheet conveying apparatus including: a sheet conveying unit; an upstream side guiding member that forms an upstream side conveying route of a sheet; a downstream side guiding member that forms a downstream side conveying route of the sheet; an upstream side detection unit; and a downstream side detection unit, wherein a detection position of the sheet for the upstream side detection unit is set between the sheet conveying unit and a position where the sheet is in contact with the upstream side guiding member, and a detection position of the sheet for the downstream side detection unit is set between the sheet conveying unit and a position where the sheet is in contact with the downstream side guiding member.

Growing community of inventors

Ibaraki, Japan

Makoto Nakura