Ricoh Company, Ltd.

Daisuke Hirano

Yasunori Ishigaya

Takahiro Imada

Yuusuke Furuichi

Tomoya Adachi

Shigeo Nanno

Takumi Waida

Keitaro Shoji

Naohiro Kumagai

Hiroshi Seo

An image forming apparatus includes a fixing device, a power supply, and a transfer device. The fixing device includes a fixing belt grounded via a protective resistor, a heater contacting the fixing belt, and a pressure rotator grounded and facing the fixing belt to form a nip. The power supply applies an alternating current voltage to the heater. The transfer device includes a transferor grounded and an opposed rotator facing the transferor to form a nip. The transferor has a transfer resistance Rt satisfying a following expression, where Rf is a resistance value of the protective resistor, Rp is a resistance value of a recording medium, jXs is an impedance of the fixing belt, and jXh is an impedance of the heater.

Image forming apparatus having transfer member with specific resistance

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 rotator, a heater, a heater holder, and a first high thermal conduction member. The heater includes a base and a plurality of heat generators being arranged on the base and including neighboring heat generators. The heater has a gap area between the neighboring heat generators. The first high thermal conduction member has a higher thermal conductivity than the base and faces the gap area.

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.

A heating device includes a planar heater, a rotator, a pressure rotator, a heating device frame, a resistor, and a discharger. The pressure rotator has a conductive outer surface and presses the rotator. The heating device frame holds the pressure rotator. The discharger is in contact with the conductive outer surface of the pressure rotator and grounded via the resistor and the heating device frame.

Heating device, fixing device, drying device, laminator, and image forming apparatus

A heating device includes a heating rotator, a pressure rotator, a planar heater, and a holder. The pressure rotator is configured to press against the fixing rotator to form a nip through which the recording medium is conveyed. The planar heater includes a plurality of heat generators arranged side by side and at least one separation region between the plurality of heat generators. The holder holds the planar heater and contacts the planar heater in a pressure direction in which the pressure rotator presses the heating rotator. The holder includes at least one clearance structure configured to cause a contact area between the planar heater and a portion of the holder corresponding to the at least one separation region to be smaller than a contact area between the planar heater and a portion of the holder not corresponding to the at least one separation region.

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Kanagawa, Japan

Daisuke Hirano