Patent ID: 7769333

Claim:
A fusing device usable with an image forming apparatus, the fusing device comprising: a pressing member; a belt member to rotate in contact with the pressing member; a nip forming member to support the belt member so that nip areas are formed on the pressing member and the belt member at contacting portions thereto; a heating member disposed away from the nip areas, to heat the belt member; and a tension application member to stiffen the belt member so that the heating member is tightly contacted with the belt member, the tension application member comprises: a tension roller to contact an inner circumference of the belt member from a direction opposite to the nip forming member; and an elastic member to support the tension roller elastically in a direction opposite to the nip forming member, wherein the nip forming member has a non-round shape, has a nip forming surface which is substantially plane along an axial direction corresponding to the nip areas, and does not rotate.