Patent ID: 8737895

Claim:
A fixing device for thermally fixing a developing agent image to a sheet fed in a sheet feeding direction comprising: a flexible tubular 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 and made of a metal plate, the inner peripheral surface configured to be in sliding contact with the nip member; a backup member configured to provide a nip region in cooperation with the nip member for nipping the flexible tubular member between the backup member and the nip member, the nip member including: a base portion having a plate-shaped configuration provided with a first end and a second end positioned downstream of the first end in the sheet feeding direction, the nip region being defined exclusively by the base portion and the backup member; a connecting portion extending from the first end of the base portion in a direction away from the backup member, the connecting portion having a first end and a second end connected to the first end of the base portion; and a flange portion extending from the first end of the connecting portion in a direction opposite to the sheet feeding direction, the connecting portion and the flange portion defining a retaining portion at a position confronting the inner peripheral surface of the flexible tubular member for retaining a lubricant agent therein, the retaining portion being formed by curving the metal plate; and a temperature detection member disposed in the internal space and configured to detect a temperature of the nip member, the nip member further including a protruding portion protruding from the second end of the base portion in the sheet feeding direction, the protruding portion having a first surface and a second surface opposite to the first surface and contacting the inner peripheral surface of the flexible tubular member, the temperature detection member being disposed on the first surface.