FIXING DEVICE AND IMAGE FORMING APPARATUS HAVING THE FIXING DEVICE

PROBLEM TO BE SOLVED: To provide a fixing device, which includes a fixing belt wound around a fixing roller and a heat roller and rotated, a pressure roller disposed in firm contact with the fixing belt, and a tension roller disposed in contact with the fixing belt and applying tension to the fixing belt, and which passes a recording medium, holding thereon a toner image to be fixed, between the fixing belt and the pressure roller, thereby fixing the toner image, the image fixing device being devised to prevent the occurrence of cold offset resulting from a fall in the temperature of each of the widthwise edge areas of the fixing belt. SOLUTION: The diameter D1 of each of the axial end parts ER and EL of the tension roller 39 is set greater than the diameter D2 of the axial middle part CL of the tension roller 39. COPYRIGHT: (C)2007,JPO&INPIT