| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of highly accurately controlling the temperature of a heating rotary body to the minimum value required for securing fixability.SOLUTION: A fixing device 20 includes a heating roller 20a, a pressure roller 20b, and a heating part 20c. The heating roller 20a comprises an endless belt 43 and a sponge rubber 42 being in contact with the inner circumferential surface of the belt 43. The pressure roller 20b is in press-contact with the belt 43. The heating part 20c heats the belt 43. The fixing device 20 fixes a toner image to a sheet P passing through between the heating roller 20a and the pressure roller 20b. A control unit 30 estimates a heat storage amount &Sgr;X indicating the amount of heat stored in the heating roller 20a and controls the heating part 20c on the basis of the heat storage amount &Sgr;X. |
