Patent ID: 8737853

Claim:
A fixing device for thermally fixing a developing agent image to a sheet fed in a sheet feeding direction comprising: a fixing frame having an upper casing and a lower casing, the lower casing being configured to move relative to the upper casing in the sheet feeding direction, the upper casing including a guide member configured to be linearly movably supported by the upper casing; a tubular flexible fusing member having an inner peripheral surface defining an internal space; a heater disposed in the internal space and configured to radiate radiant heat; a nip member disposed in the internal space and configured to receive the radiant heat from the heater and to be supported by the guide member, the inner peripheral surface being in contact with the nip member; a resiliently deformable backup member configured to provide a nip region in cooperation with the nip member upon nipping the fusing member between the backup member and the nip member, the backup member configured to be supported by the lower casing, and the backup member confronting the nip member in a confronting direction; a release mechanism configured to provide a nip release state by linearly moving the guide member away from the backup member in the confronting direction to release a nip pressure between the nip member and the backup member, the release mechanism being further configured to restrict the guide member from moving toward the backup member to maintain the nip release state; and an adjustment mechanism configured to move the lower casing relative to the upper casing in the sheet feeding direction to move the backup member relative to the nip member between a first position and a second position different from the first position in the sheet feeding direction to adjust the sheet feeding direction when the release mechanism maintains the nip release state, wherein, when the backup member is in the first position and in the second position, the release mechanism is further configured to allow the guide member to linearly move toward the backup member to remove the nip release state, the nip member and the backup member being brought into pressure contact with each other to provide the nip pressure when the nip release state is removed.