Patent ID: 8774692

Claim:
A fixing device for processing a toner image on a recording medium, the device comprising: a fuser member; a stripper member parallel to the fuser member; an endless rotary belt looped for rotation around the fuser member and the stripper member in a longitudinal, conveyance direction of the belt; a heater adjacent to the belt to heat the belt; a pressure member opposite the fuser member via the belt, the fuser member and the pressure member pressing against each other via the belt to form a fixing nip therebetween through which the recording medium is conveyed under heat and pressure, the recording medium after passage through the nip remaining in contact with the belt as the belt moves from the fuser member toward the stripper member, and separating from the belt as the belt passes around the stripper member; and a belt cooler including at least three cooling rollers inside the loop of the belt, each of which contacts the belt to rotate at a uniform speed with the belt, while maintained at a temperature lower than that of the belt to absorb heat from the belt to in turn cool the recording medium in contact with the belt, each of the cooling rollers being tangential to an inner circumferential surface of the belt to retain the belt in a curved configuration with a constant radius of curvature, at least one of the cooling rollers having a different diameter than that of the other cooling rollers.