An image forming apparatus includes a fixing device that includes an endless belt to convey a print medium, a heating roller to heat the endless belt, a pressing roller that presses the endless belt against the heating roller along a nip region of the endless belt, and a conveyance switching device to move the endless belt between a first position that directs the print medium away from the endless belt when the print medium exits the nip region, and a second position that conveys the print medium to remain in contact with the endless belt when the print medium exits the nip region.

A thermopile sensor that is a temperature measuring device of a fusing device is held on a substrate. The substrate is provided with a cylindrical member extending in front of the thermopile sensor and an aperture disposed at an end of the cylindrical member.

An image forming apparatus includes a fixing device and a cooling device provided on a side downstream of the fixing device with respect to a sheet feeding direction. The cooling device includes a first unit including a first belt and a first roller, a second unit including a second belt for forming a nip in cooperation with the first belt, a heat sink and a second roller, and a driving motor for rotating the first roller and the second roller. The second unit is movable between a contact position where the first belt and the second belt are in contact with each other so as to form the nip and a separated position where the first belt and the second belt are in separation from each other so as to release the nip.

A fixing device includes a fixing belt that is endless and rotatable. A nip formation pad is disposed opposite an inner circumferential face of the fixing belt via a lubricant. A pressure roller sandwiches the fixing belt together with the nip formation pad to form a pressing region through which a recording medium is conveyed. A cap is disposed opposite a lateral end of the fixing belt in an axial direction of the fixing belt. A seal is tubular and contacts an outer circumferential face of the fixing belt in at least a part of an inner circumferential face of the seal. The seal seals a gap between the cap and the fixing belt. The seal includes a non-perpendicular portion that is not perpendicular to a circumferential direction of the fixing belt and defines a slit.

In a fixing device, a first fixing member and a second fixing member are configured to form a nip in combination, and an arm biased by a first spring with a first biasing force provides a nip pressure. A cam rotatably arranged to cause the arm to move against the first biasing force has a first cam surface used to change the nip pressure from a first pressure to a second pressure smaller than the first pressure, and a second cam surface of which an angle of action is greater than that of the first cam surface to change the nip pressure from the second pressure to a third pressure smaller than the second pressure. A maximum pressure angle at the second cam surface is smaller than a maximum pressure angle at the first cam surface.

A resistance heating component is to come into contact with and heat a fixing belt made of a heat resistant material, and is to be provided at a position away from a fixing area between which the resistance heating component and the fixing belt a recording material is held and conveyed, the resistance heating component including: a metal base material having a low heat capacity; and a resistance heating layer laminated on a front surface or a rear surface of the base material with an insulating layer interposed between the base material and the resistance heating layer.

A heater holder includes a restriction portion and a recessed portion. The restriction portion determines the position of a cable in the longitudinal direction of the heater. The recessed portion, against which a bare conductive portion of the cable is to be positioned, is provided at a position that is different from the position of the restriction portion as viewed in a direction intersecting with the longitudinal direction. A wire is joined to the bare conductive portion somewhere between the restriction portion and the recessed portion.

A fixation device according to one of embodiments includes a first and second fixation units. The first fixation unit includes: a first belt; a first pad with a first elastic layer; and a first roller provided downstream of the first pad in a conveyance direction of a medium. The second fixation unit includes: a second belt; a second pad including a second elastic layer and pressed against the first pad with the first and second belts interposed in between; and a second roller provided downstream of the second pad in the conveyance direction and pressed against the first roller with the first second belts interposed in between. A thickness of at least one of the first and second elastic layers is smaller on a downstream side in the conveyance direction than on an upstream side in the conveyance direction.

An endless belt includes a polyimide resin layer in which a content of at least one solvent selected from a solvent group A consisting of a urea solvent, an alkoxy group-containing amide solvent, and an ester group-containing amide solvent is from 50 ppm to 2,000 ppm.

A fixing device includes a separator disposed downstream from a nip former in a recording medium conveyance direction and isolated from a pressure rotator via a fixing belt. The separator stretches the fixing belt. A presser is interposed between a fixing nip formed between the living belt and the pressure rotator and an upstream end of the separator in a rotation direction of the fixing belt. The presser comes into contact with an inner circumferential surface of the fixing belt to press the fixing belt against the pressure rotator. A pressure adjuster, contacting the pressure rotator, changes a pressing position of the pressure rotator relative to the fixing belt to adjust pressure exerted from the pressure rotator to the fixing belt. A presser position adjuster, contacting the presser, changes a presser position of the presser relative to the fixing belt according to the pressing position of the pressure rotator.