Ricoh Company, Ltd.

Keitaro Shoji

Yasunori Ishigaya

Hiromasa Takagi

Kazuya Saito

Toshihiko Shimokawa

Yutaka Ikebuchi

Kenji Ishii

Ryuuichi Mimbu

Takayuki Seki

Ryohei Matsuda

Yoshio Hattori

Yoshiki Yamaguchi

Takumi Waida

Motoyoshi Yamano

Yuji Arai

Arinobu Yoshiura

Shuji Hirai

Haruyuki Honda

Ryota Yamashina

Kohichi Utsunomiya

Hideo Nagafuji

Shohei Saito

Terumichi Ochi

Daisuke Hirano

Qifeng Cui

Takahiro Imada

Takuya Seshita

Shinji Kato

Yuusuke Furuichi

Tomoya Adachi

Yoshikuni Sasaki

Yuma Matsumoto

A sheet conveyor includes a heating device to heat a recording medium and a recording medium sensor to detect the recording medium. The heating device includes a heater, a first temperature sensor to detect a temperature of the heater, and a second temperature sensor to detect the temperature of the heater. The heater has a first heat-distribution amount region on one side and a second heat-distribution amount region on the other side, in a conveyance orthogonal direction with respect to a reference position. The first heat-distribution amount region is greater in heat distribution amount than the second heat-distribution amount region. The first temperature sensor is disposed farther from the reference position than the second temperature sensor in the conveyance orthogonal direction. The first temperature sensor is disposed in the second heat-distribution amount region. The recording medium sensor is disposed in the first heat-distribution amount region.

Sheet conveyor and image forming apparatus incorporating the sheet conveyor

A heating device includes: a pair of rotators to form a nip; a heating source having a heat generation area to heat at least one rotator; temperature sensors to detect a temperature of the heating source, a member in contact with the heating source, or one rotator; and a sheet sensor to detect a sheet passing through the nip. The temperature sensors include: a first temperature sensor closer to one end than a center of the heat generation area in the longitudinal direction; and a second temperature sensor closer to the center than the first temperature sensor is. The second temperature sensor is at a position shifted from the center of the heat generation area toward the first temperature sensor. The sheet sensor is on a side opposite a side on which the first temperature sensor is disposed with reference to the center of the heat generation area.

Heating device, fixing device, and image forming apparatus with a single sheet sensor

A conveyance device to convey a recording medium includes a heater, a first temperature detector, a second temperature detector, and a recording medium detector. The heater heats the recording medium. The first temperature detector and the second temperature detector detect a temperature of the heater. The recording medium detector detects the recording medium. The first temperature detector is disposed at a position farther from a center position of a heating region of the heater than the second temperature detector in a conveyance orthogonal direction. The conveyance orthogonal direction is along a surface of the recording medium and orthogonal to a direction in which the recording medium is conveyed. The recording medium detector is disposed on a side opposite to the first temperature detector with respect to the second temperature detector in the conveyance orthogonal direction.

Conveyance device and image forming apparatus

A heating device includes a heater including a heat generation portion and a base mounting the heat generation portion. The base includes a first lateral end portion and a second lateral end portion in a longitudinal direction of the base. The first lateral end portion has a first length and the second lateral end portion has a second length that is smaller than the first length in the longitudinal direction of the base. A thermal conduction aid contacts the heater and includes a first lateral end projection and a second lateral end projection that project beyond the heat generation portion in the longitudinal direction of the base. The first lateral end projection has a first volume and the second lateral end projection has a second volume that is greater than the first volume.

Heating device, fixing device, and image forming apparatus

A heating device includes a first rotator, a heater including a base and a heat generator, and a second rotator contacting the first rotator. The heat generator adjacent to the base defines a heat generation area having one edge close to one edge of the base in a longitudinal direction of the base. A length between the one edge of the base and the one edge of the heat generation area is longer than a length between the other edge of the base and the other edge of the heat generation area. The second rotator has one edge close to the one edge of the heat generation area. A length between the one edge of the second rotator and the one edge of the heat generation area is shorter than a length between the other edge of the second rotator and the other edge of the heat generation area.

An image forming apparatus includes an image forming device that forms a toner image on a recording medium, a first rotator, and a second rotator that presses against the first rotator to form a nip therebetween. The first rotator conveys the recording medium bearing the toner image through the nip with a first orientation of the recording medium to fix the toner image on the recording medium to create a cleaning sheet bearing a cleaning image in a cleaning sheet creation mode. The first rotator conveys the cleaning sheet bearing the cleaning image through the nip with a second orientation of the cleaning sheet, that is different from the first orientation of the recording medium, such that the cleaning image is disposed opposite the first rotator to cause the cleaning image to remove a foreign substance from a surface of the first rotator in a cleaning mode.

Image forming apparatus and cleaning method

A fixing device includes a fixing rotator being rotatable and a heater to heat the fixing rotator. The heater includes a tube, a heat generator, disposed inside the tube, to generate heat, and a sealing portion, disposed at each lateral end of the tube in a longitudinal direction of the heater, to seal the tube. A reflector reflects heat radiated from the heater toward the fixing rotator. The reflector includes an outboard edge being disposed inboard from at least a part of the sealing portion in an axial direction of the fixing rotator.

Fixing device and image forming apparatus

A fixing device includes a fixing rotator being rotatable and a heater to heat the fixing rotator. The heater includes a tube, a heat generator, disposed inside the tube, to generate heat, and a sealing portion, disposed at each lateral end of the tube in a longitudinal direction of the heater, to seal the tube. The sealing portion includes an inboard edge. A reflector reflects heat radiated from the heater toward the fixing rotator. The reflector includes an outboard edge being disposed inboard from the inboard edge of the sealing portion in an axial direction of the fixing rotator.

A fixing device includes a rotatable endless belt formed into a loop and a heater disposed opposite the endless belt to heat the endless belt. A nip formation pad is disposed inside the loop formed by the endless belt. The nip formation pad includes a metallic thermal equalizer extending in an axial direction of the endless belt. A rotatable pressure rotator presses against the nip formation pad via the endless belt to form a fixing nip between the endless belt and the pressure rotator, through which a recording medium bearing a toner image is conveyed. The pressure rotator includes an increased tackiness portion disposed at a lateral end of the pressure rotator in an axial direction of the pressure rotator to transmit a driving force to the endless belt. The increased tackiness portion is disposed opposite the thermal equalizer of the nip formation pad.

A fixing device includes a primary heater and a secondary heater that heat a fixing rotator. The primary heater includes a primary major heat generation portion and a primary minor heat generation portion. The primary minor heat generation portion includes a major heat generator that generates an increased amount of heat and a minor heat generator that generates a decreased amount of heat smaller than the increased amount of heat generated by the major heat generator. The major heat generator has a width in an axial direction of the fixing rotator that is not smaller than 30 percent and not greater than 35 percent with respect to a width of the primary minor heat generation portion in the axial direction of the fixing rotator. A temperature detector is disposed opposite the minor heat generator of the primary heater to detect a temperature of the fixing rotator.

A fixing device includes an endless fixing belt that is multilayered, an opposing rotator disposed opposite the fixing belt and pressed to the fixing belt to form a nip, a heater disposed inside the fixing belt, and a safety device including a contactless temperature sensor disposed outside the fixing belt and apart from an outer face of the fixing. The fixing belt is to rotate and thermally expand. The contactless temperature sensor detects a temperature of the fixing belt. The safety device stops heating by the heater when the temperature detected by the contactless temperature sensor is at or higher than a predetermined temperature. As the outer face of the fixing belt shifts outward in the radial direction due to thermal, a proportion of the outer face of the fixing belt in a viewing angle of the contactless temperature sensor increases.

An image forming apparatus includes a fixing device to fix a toner image onto a recording medium, a voltmeter to measure an input voltage from an external source, and a controller operatively connected to the fixing device and the voltmeter. The fixing device includes an endless, fixing rotator formed into a loop, a heater to heat the fixing rotator, a pressure pad disposed inside the loop, and a pressure rotator disposed opposite the pressure pad via the fixing rotator to press the fixing rotator against the pressure pad to form a fixing nip between the fixing rotator and the pressure rotator, through which the recording medium bearing the toner image is conveyed. The controller controls a heating operation of the heater and a fixing operation of the fixing device to fix the toner image onto the recording medium, based on the input voltage measured by the voltmeter.

Image forming apparatus incorporating fixing device

A fixing device includes a fixing belt and an opposed rotator to press against a nip formation pad via the fixing belt to form a fixing nip between the fixing belt and the opposed rotator. A primary heater and a secondary heater heat the fixing belt. The secondary heater includes a lateral end heat generator. The nip formation pad includes a base and at least one thermal conductor being interposed between the base and the fixing nip and having a thermal conductivity greater than a thermal conductivity of the base. The at least one thermal conductor includes an outboard edge disposed between an inboard edge and an outboard edge of the lateral end heat generator and disposed outboard from a conveyance span of the fixing belt in an axial direction of the fixing belt, where a recording medium is conveyed over the fixing belt.

A fixing device includes a primary heat generator and a secondary heat generator to heat an endless belt and a temperature detector, disposed opposite the secondary heat generator, to detect a temperature of the endless belt. The secondary heat generator includes an inboard edge and an outboard edge disposed outboard from the inboard edge in an axial direction of the endless belt. The secondary heat generator has an inboard length defined between a center of a detection span of the temperature detector and the inboard edge in the axial direction of the endless belt. The secondary heat generator further has an outboard length defined between the center of the detection span of the temperature detector and the outboard edge in the axial direction of the endless belt. The secondary heat generator defines a ratio of the outboard length to the inboard length that is greater than 7/3.

A fixing device includes an endless fixing belt; a pressure roller to contact the fixing belt; a nip forming member to press the pressure roller from the fixing belt; a nip portion formed between the fixing belt and the pressure roller; a heater to heat the fixing belt to fuse and fix toner onto a recording sheet in the nip portion; an auxiliary driven roller; an auxiliary drive roller to drive the driven roller; an auxiliary nip portion, formed between an outer circumferential surface of the auxiliary driven roller and an outer circumferential surface of the auxiliary drive roller, to nip the recording sheet after toner fixation conveyed from the nip portion; and an outlet guide member, disposed downstream of the auxiliary nip portion, to guide the recording sheet after toner fixation conveyed from the auxiliary nip portion, with the toner-fixed recording sheet surface bent in a concave shape.

Growing community of inventors

Kanagawa, Japan

Keitaro Shoji