IMAGE HEATING DEVICE AND IMAGE FORMING DEVICE

摘要

PROBLEM TO BE SOLVED: To realize the automatic self temperature control of a heating element itself optimum for fixation and to prevent partial temperature deviation or excessive temperature rising by using a heat generating member made of a magnetic layer and constituting it so that the ratio of its calorific value equal to or above Curie temperature to the calorific value at ordinary temperature when it is excited may be equal to or under a specified value. SOLUTION: In a heating roller 21, magnetic alloy adjusted to obtain the specified Curie temperature is set as base substance and the surface thereof is coated with fluororesin. An induction heating part is constituted by an exciting coil 23 and an alternating power source 24 arranged inside the roller 21. The magnetic alloy of the roller 21 has thickness twice or more as thick as surface depth corresponding to exciting frequency and is constituted so that the calorific value equal to or above the Curie temperature is <=1/2 of the calorific value at the ordinary temperature when it is excited. Since the roller 21 itself has self temperature control characteristics, the temperature control is automatically performed by setting the Curie temperature to an appropriate value for fixing temperature.