Patent ID: 7203453

Claim:
A fixing device comprising: an endless fixing belt which is tensionless in a circumferential direction at a center part of the width direction of the belt and supported to circularly move; a heating device that heats the fixing belt; a pressure roll which is contacted with an outer peripheral face of the fixing belt and supported to rotate around an axis of the pressure roll; a pressure member which is contacted with an inner peripheral face of the fixing belt to exert pressure on the pressure roll interposing the fixing belt; and a support member which is passed through inside the fixing belt and supports the pressure member, wherein a fixing nip part is formed between the fixing belt and the pressure roll, an unfixed toner image on a recording medium which passes the nip part is pressured and heated to be a fixed image, the fixing belt is kept in a round shape in the circumferential direction near edges of both sides of the fixing belt, and the fixing belt is supported to rotate around a center axis which is determined by both end parts of the support member.