An image forming apparatus includes an image forming portion configured to form a toner image on a sheet, a fixing portion configured to heat and pressurize the sheet bearing the toner image to fix the toner image to the sheet, a shutter provided to be movable to an open position at which the shutter opens an opening that the sheet being conveyed toward the fixing portion is able to pass through, and a closed position at which the shutter closes the opening, an urging portion configured to urge the shutter toward the open position, and an abutment portion that the shutter urged toward the open position by the urging portion abuts to be positioned at the open position.

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 mechanism for shutting off drive so that drive of pressing release is not rotated even when a pressing roller is rotated as a driving source is provided, and a torque when drive of a shutting-off portion is connected is set at a torque value to which a one-way idling torque is added. Therefore, during jam clearance, connection of pressing release drive by pressing roller rotation can be carried out.

A disclosed fixing device includes a pressing member; an endless tubular fixing member disposed opposite to the pressing member; a heating source configured to heat the fixing member; a nip forming member disposed opposite to the pressing member via the fixing member to form a nip portion; and a supply unit configured to supply lubricant to a portion of an inner surface of the fixing member, the portion facing the nip forming member, wherein the nip forming member includes a contact portion that contacts the inner surface of the fixing member, the contact portion includes a guide portion for guiding lubricant, and the guide portion is formed by extending obliquely from opposite ends in a width direction toward a center of the fixing member as the contact portion moves from upstream to downstream in a rotational direction of the fixing member.

According to one embodiment, a fixing device includes a belt, a heater, and a holder. The holder has a plurality of support portions that contact an end of the first heating region and an end of the second heating region along the direction perpendicular to the transport direction, and a plurality of non-contacting portions that do not contact the end of the first heating region and the end of the second heating region between the plurality of support portions, the end of the second heating region contacts one of the plurality of support portions at a side in the direction perpendicular to the transport direction, and the end of the second heating region faces to one of the plurality of non-contacting portions at the other side in the direction perpendicular to the transport direction.

A fixing device includes a fixing rotator, an opposing rotator, a temperature detector, and a support. The fixing rotator has a hollow and heats an image to fix the image onto a recording medium. The opposing rotator forms a fixing nip between the fixing rotator and the opposing rotator. The temperature detector includes an exposed conductive portion. The support has conductivity and is disposed in the hollow of the fixing rotator to support the fixing rotator at the fixing nip. The support has at least one of a recessed portion or an opening at a position facing the exposed conductive portion of the temperature detector.

A driving transmission device includes a storage part, a fixing pin and a supporting part. The storage part has a through hole. The fixing pin rotatably supports a gear. To the supporting part, the fixing pin is fixed. A hole side chamfered portion is formed at an outside opening edge of the through hole. A shaft side chamfered portion is formed at the tip end portion of the fixing pin. A lubricant is applied to a contact area between the fixing pin and the through hole. A hole side boundary portion between an inner circumferential surface of the through hole and the hole side chamfered portion is in contact with an outer circumferential surface of the fixing pin. A shaft side boundary portion between an outer circumferential surface of the fixing pin and the shaft side chamfered portion faces the hole side chamfered portion with a gap.

An image heating apparatus includes a first rotary member, a second rotary member, a frame member, a guide portion, and a cover. The first rotary member is configured to heat a toner image formed on a recording material. The second rotary member is configured to contact the first rotary member and form a fixing nip portion with the first rotary member. The frame member is configured to support the first rotary member and the second rotary member. The guide portion is configured to guide the first rotary member to be moved upstream in a conveyance direction of the recording material when the first rotary member is being removed. The cover is attached to the frame member and configured to turn around a rotation shaft to open and close the guide portion. The cover is configured to turn in a direction toward the conveyance direction to open the guide portion.

An image forming apparatus, having a cartridge and a main body, is provided. The cartridge has a cartridge-side coupling to transmit a driving force to a drivable member in the cartridge. The cartridge is detachably attached to the main body. The main body includes a body-side coupling movable between a connecting position, at which the body-side coupling is connected with the cartridge-side coupling, and a separated position, at which the body-side coupling is separated from the cartridge-side coupling; a joint cam movable between a first position, at which the joint cam locates the body-side coupling at the connecting position, and a second position, at which the joint cam locates the body-side coupling at the separated position; and a rotator having a dent. The dent allows entry of an end portion of the joint cam there-into when the joint cam is located at the first position.

In general, a fixing device according to an embodiment includes an endless belt, a pressure element, a heating member, an adjustment mechanism, and a controller. The pressure element conveys a sheet while interposing the sheet under pressure between the same and the endless belt. The heating member is provided on the inner side of the endless belt and has a heat generating element for heating the endless belt. The adjustment mechanism moves at least one of the heating member and the pressure element in such a direction as to bring the one closer to or away from the other, to adjust the nip width which is the length of an interposing and pressurizing region in a sheet conveyance direction, the interposing and pressurizing region being formed by the heating member and the pressure element to interpose the endless belt under pressure. The controller controls the adjustment mechanism so that A>B≧N is satisfied, where A is the nip width during a fixing process in which the sheet is heated to fix a color material onto the sheet, B is the nip width during temperature raising of the heating member to be conducted before the fixing process, and N is the length of the heat generating element in the sheet conveyance direction.