Patent ID: 7502585

Claim:
A fixing device for fixing a toner image carried on a recording material, comprising: an elliptically-shaped belt member that rotates in a state where its major axis is set in a transporting direction of the recording material and its minor axis is set in a direction orthogonal to the transporting direction of the recording material; a belt guide member contacting an inner surface of the belt member having an outer surface formed in a horizontal plane at an area corresponding to a nip part; and a pressing member disposed in pressure contact with a surface of the belt member intersecting a direction of the minor axis of the belt member to form the nip part through which the recording material passes, wherein; the main axis of the belt member is longer than the minor axis of the belt member; and wherein the belt member is formed in the horizontal plane at the area corresponding to the nip part; and wherein the belt guide member has an upstream curved portion formed upstream of the nip part in the transporting direction of the recording material and a downstream curved portion formed downstream of the nip part, and a radius of curvature of the downstream curved portion is formed to be smaller than a radius of curvature of the upstream curved portion.