Ricoh Company, Ltd.

Tetsuo Tokuda

Kenji Ishii

Hiroshi Yoshinaga

Toshihiko Shimokawa

Masaaki Yoshikawa

Naoki Iwaya

Ippei Fujimoto

Yoshiki Yamaguchi

Yutaka Ikebuchi

Takahiro Imada

Takamasa Hase

Takuya Seshita

Akira Shinshi

Kenichi Hasegawa

Arinobu Yoshiura

Yuji Arai

Hiromasa Takagi

Hajime Gotoh

Shuntaroh Tamaki

Fumihiro Hirose

Motoyoshi Yamano

Akiyasu Amita

Naoto Suzuki

Takashi Sakamaki

Hironori Yamaoka

Satoshi Ueno

Kohichi Utsunomiya

Ryohhei Sugiyama

Hiroshi Ono

Yoshikuni Sasaki

Masateru Ujiie

Jun Okamoto

Daisuke Arai

Takashi Seto

Takashi Fujita

Teppei Kawata

Hiroshi Seo

Shinichi Namekata

Seiji Saitoh

Yohhei Watanabe

Hideo Nagafuji

Yamano Motoyoshi

Kenji Ishi

Yutaka Ikebuchii

Toshihiko Shimokkawa

A fixing device includes a heater, a fixing rotator, a first temperature sensor, a second temperature sensor, a contact rotator, and circuitry. The fixing rotator has an outer circumferential surface having a first area and a second area. The first area contacts both a first sheet and a second sheet having a width narrower than the width of the first sheet. The second area contacts the first sheet but does not contact the second sheet. The first temperature sensor detects a first temperature of the first area. The second temperature sensor detects a second temperature of the second area. The contact rotator contacts both the first area and the second area and rotates at the one of at least two relative velocities with respect to the fixing rotator. The circuitry sets one of the at least two relative velocities based on the first temperature and the second temperature.

Fixing device and image forming apparatus incorporating same

An image forming apparatus includes a fixing device and circuitry. The fixing device includes a fixing rotator, an electromagnetic induction heater configured to heat the fixing rotator, and a magnetic flux control member. The circuitry is configured to control the electromagnetic induction heater to lead a temperature of the fixing rotator to a target temperature and change an upper limit of power supplied to the electromagnetic induction heater based on the target temperature.

Image forming apparatus

A belt device includes an endless belt, a plurality of support rotators configured to support the endless belt, and a support configured to support shaft portions of the plurality of support rotators. The support has an attaching and detaching path through which the shaft portions of the plurality of support rotators pass in a direction orthogonal to an axial direction of at least one of the plurality of support rotators when the shaft portions of the plurality of support rotators are detached from the support.

Belt device and image forming apparatus incorporating same

An image forming apparatus includes a fixing rotator rotatable in a predetermined direction of rotation, over which a recording medium is conveyed, and a heater to heat the fixing rotator. A temperature detector detects a temperature of the fixing rotator. A controller performs a primary productivity control to define a primary productivity rate of printing per unit time based on the temperature of the fixing rotator that is detected by the temperature detector. The controller calculates an amount of power suppliable to the heater and performs a secondary productivity control simultaneously with and separately from the primary productivity control. The secondary productivity control defines a secondary productivity rate of printing per unit time based on the amount of power suppliable to the heater. The controller selects one of the primary productivity rate and the secondary productivity rate whichever is lower as a productivity rate of the image forming apparatus.

Image forming apparatus and image forming method with temperature and power-based productivity rate selection

An image forming apparatus includes a fixing belt stretched across a first roller and a second roller including an elastic layer. A pressure rotator presses against the second roller via the fixing belt to form a fixing nip between the pressure rotator and the fixing belt. A recording medium bearing a toner image is conveyed through the fixing nip. A clearance detector detects a clearance between the first roller and the second roller. A mover moves the pressure rotator with respect to the second roller in a pressing direction in which the pressure rotator presses against the second roller via the fixing belt and a separation direction in which the pressure rotator separates from the second roller. A controller controls an amount of movement of the pressure rotator moved by the mover toward the second roller based on the clearance detected by the clearance detector.

Image forming apparatus including a fixing device

A fixing device may include an endless fixing member; a heater inside the fixing member; and a nip forming unit configured to form a nip through which a recording sheet is conveyed, the nip forming unit including a supporting member and a contact member supported by the supporting member, the supporting member including at least one contact surface and the contact member including a plurality of protrusions protruding towards the supporting member such that two or more of the plurality of protrusions are configured to contact one of the at least one contact surface of the supporting member, each of the plurality of protrusions having a height associated there with such that the height of the plurality of protrusions increases in a direction from ends of the contact member towards a center of the contact member.

Fixing device and image forming apparatus

A fixing device includes a heater, a fixing rotator, a pressure rotator to press against the fixing rotator to form a fixing nip between the fixing rotator and the pressure rotator, through which a recording medium is conveyed, a moving device to move the pressure rotator in directions in which the pressure rotator comes into contact with and separates from the fixing rotator, a thermal expansion amount predictor to predict an amount of thermal expansion of the fixing rotator while the recording medium is conveyed, and a nip width adjuster to control a moving distance of the pressure rotator moved by the moving device toward the fixing rotator, depending on the amount of thermal expansion of the fixing rotator predicted by the thermal expansion amount predictor, so as to adjust a width of the fixing nip to maintain a substantially constant width of the fixing nip.

Fixing device, image forming apparatus, and method of controlling fixing device

A fixing device includes a fixing rotator rotatable in a predetermined direction of rotation and a pressure rotator to press against the fixing rotator to form a fixing nip therebetween, through which a recording medium bearing a toner image is conveyed. A rotation load applicator is coupled to one of the fixing rotator and the pressure rotator to apply a rotation load to the one of the fixing rotator and the pressure rotator. The rotation load is in a range of from 0.1 Nm to 0.6 Nm.

Fixing device and image forming apparatus including a rotation load applicator

A drive transmission unit transmits driving force to a driven unit including a driven rotator coupled to the drive transmission unit via a unit coupler. The drive transmission unit includes a driving source, a drive transmission member to transmit driving force from the driving source to the driven rotator by engaging the driven rotator, and a basal plate with a turning shaft portion at one end thereof. The basal plate supports the driving source and the drive transmission member thereon. The drive transmission unit is turned around the turning shaft portion together with the driven unit in a direction substantially orthogonal to a direction of a driving reaction force applied to the drive transmission member when the driven rotator receives the driving force from the drive transmission member.

Drive transmission unit, fixing device with drive transmission unit, and image forming apparatus having fixing device with drive transmission unit

A fixing device may include an endless fixing member; a heating unit that is provided inside an inner peripheral surface of the fixing member; and a nip forming unit that comes into press-contact with a rotationally driven pressing member with the fixing member interposed therebetween to form a nip. The nip forming unit has a shape in which a center of a contact surface protrudes toward the pressing member compared to both ends. The nip forming unit has a protruding amount at a center toward the pressing member compared to both ends of the nip forming unit in no-load state is set to be less than a bent amount of the nip forming unit when the nip forming unit comes into press-contact with the pressing member with the fixing member interposed therebetween.

A fixing device includes a fixing rotary body to come into contact with a toner image on a recording medium and a pressing rotary body separably pressed against the fixing rotary body to press the recording medium against the fixing rotary body. A cooler, disposed opposite the pressing rotary body to cool the pressing rotary body, includes a fan to move air to the pressing rotary body and at least one inlet duct interposed between the fan and the pressing rotary body to supply air from the fan to the pressing rotary body. The at least one inlet duct selectively cools the pressing rotary body in a variable axial span in an axial direction thereof.

A fixing device includes an exciting coil to generate a magnetic flux and a heat generation layer disposed opposite the exciting coil to generate heat by the magnetic flux from the exciting coil. A temperature sensitive magnetic body, disposed opposite the exciting coil via the heat generation layer, obtains and loses magnetism at a temperature defined by a Curie temperature by composition adjustment to selectively create a heating region and a non-heating region of the heat generation layer. A degausser is made of a non-magnetic material having an electrical resistivity smaller than an electrical resistivity of the temperature sensitive magnetic body. The degausser is disposed opposite the exciting coil with an interval in a range of from about 4.2 mm to about 8.2 mm.

A fixing device includes a substantially cylindrical metal member, a heater, an endless, flexible fixing member, a rotary pressing member, and a stationary member. The heater heats the metal member. The fixing member is disposed rotatable around the metal member. An inner circumferential surface of the fixing member is heated by the metal member to heat and fix a toner image. The rotary pressing member is disposed opposite the metal member and pressed against an outer circumferential surface of the fixing member to form a nip between the rotary pressing member and the fixing member through which a recording medium bearing the toner image passes. The stationary member is disposed in pressure contact with the inner circumferential surface of the fixing member, and has an opposing face opposing the rotary pressing member and having a curvature smaller than a curvature of the rotary pressing member.

Fixing device and image forming apparatus including same

A fixing device includes an excitation coil, a rotatable heater, and a support shaft. The excitation coil includes a turning end and an extended portion continuous with the turning end. The heater includes a heat generation layer and a thermosensitive magnetic body composed to switch between magnetized and demagnetized states at a Curie temperature to selectively create localized heating areas in the heat generation layer. The support shaft is made of a nonmagnetic material having a lower electrical resistivity than the thermosensitive magnetic body and supports opposed ends of the heater axially along the heater. The support shaft includes a body portion having a largest outer diameter of the support shaft and an end positioned outside the turning end of the excitation coil, and support portions having a smallest outer diameter of the support shaft and supporting the heater.

A fixing device includes an exciting coil and a heat generator disposed opposite the exciting coil. The heat generator includes a heat generation layer disposed opposite the exciting coil to generate heat by a magnetic flux from the exciting coil and a temperature sensitive magnetic body disposed opposite the exciting coil via the heat generation layer to obtain and lose magnetism at a temperature defined by a Curie temperature by composition adjustment to selectively create a heating region and a non-heating region of the heat generation layer. A degausser is disposed opposite the heat generator and made of a non-magnetic material having an electrical resistivity smaller than that of the temperature sensitive magnetic body. A holder contacting and supporting the degausser is disposed inboard from a lateral edge of the degausser and outboard from a lateral end of the exciting coil in a longitudinal direction of the degausser.

Growing community of inventors

Kanagawa, Japan

Tetsuo Tokuda