Patent ID: 8750775

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 and circularly movable in a circularly-moving direction; 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 being configured to be in sliding contact with the nip member, the nip member confronting the heater in a confronting direction; 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; and a guide member disposed in the internal space and having a part positioned upstream of the nip member in the circularly-moving direction, the part being configured to guide the flexible tubular member, the part having an end portion containing a most downstream end at which the flexible tubular member is directed to a position between the nip member and the backup member; the nip member including: a base portion having 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 and being bent 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, a boundary region between the second end of the connecting portion and the first end of the base portion providing a first curved portion; and a flange portion extending from the first end of the connecting portion in a direction opposite to the sheet feeding direction and having a first end and a second end connected to the first end of the connecting portion, the flange portion defining a retaining portion in cooperation with the connecting portion at a position confronting the inner peripheral surface of the flexible tubular member for retaining a lubricant agent, the nip member and the guide member defining a first imaginary plane containing a line connecting the first curved portion and the most downstream end, the first imaginary plane being positioned opposite to the heater relative to the first end of the flange portion.