Abstract: An image heating device includes a heater generating heat upon electric power supply, and a film whose one surface slidably contacts the heater, and whose other surface moves together with a recording material bearing an image while contacting the recording material. The image on the recording material is heated by heat from the heater through the film. The device also includes a thermoprotector having a bimetal which mechanically changes in order to disconnect electric power supply to the heater when there is an excessive temperature rise. The bimetal of the thermoprotector contacts the heater.

Abstract: A timer for measuring the image formation interval, and the fixing temperature is set in response to the measured image formation interval so as to balance satisfactorily the degree of fixation, the amount of the recording material curling, and the recording material wrinkling no matter what timing is used to start the next image formation after the completion of the preceding one.