Fixing apparatus of image forming apparatus

A fixing method of a fixing apparatus comprising:

• thermally expanding an elastic roller disposed on an inner side of a metal belt by heating a metal layer of the metal belt up to a fixable temperature with induction heating such that a state, in which the outer diameter of the elastic roller is smaller than the inner diameter of the metal belt, is changed to a state in which the outer diameter of the elastic roller is larger than the inner diameter of the metal belt;
• nipping and carrying a recording medium between the metal belt and an opposite member, which can be pressed against and come in contact with the metal belt, and fixing a toner image on the recording medium;
• contracting the elastic roller by stopping induction heating of the metal layer such that the outer diameter of the elastic roller becomes smaller than the inner diameter of the metal belt;
• detaching the metal belt from the outer periphery of the elastic roller by causing the metal belt to slide when the elastic roller contracts such that the outer diameter of the elastic roller becomes smaller than the inner diameter of the metal belt;
• and
• disposing the elastic roller on an inner side of a new metal belt.