Patent ID: 8676102

Claim:
A fixing device for thermally fixing a developing agent image to a sheet fed in a sheet feeding direction comprising: a tubular flexible fusing member having an inner peripheral surface defining an internal space; a heater disposed in the internal space; a nip member disposed in the internal space, the inner peripheral surface of the tubular flexible fusing member being in contact with the nip member; a backup member configured to provide a nip region in cooperation with the tubular flexible fusing member upon nipping the tubular flexible fusing member between the backup member and the nip member, the backup member facing the nip member in a facing direction; and a temperature detection element disposed in a superposed region of the nip member superposed with the nip region in the facing direction and configured to detect a temperature of the superposed region, wherein the nip member is formed of a plate member having a thickness in the facing direction and formed with a hole extending in the sheet feeding direction, the nip member having a first surface in direct confrontation with the heater and a second surface in confrontation with the backup member via the tubular flexible fusing member, and the hole being spaced away from the first surface and the second surface, wherein the temperature detection element has a length in the facing direction smaller than that of the nip member, the temperature detection element being embedded in the hole.