FIXING DEVICE

PROBLEM TO BE SOLVED: To provide a fixing device capable of always performing stable fixing, even in the case when printing is started by turning on a power source after releasing a JAM or in the morning of a winter season. SOLUTION: This fixing device is provided with a heating roller 1 with a built in heater 2, the pressure roller 4 held in press contact with the heating roller 1 in freely rotationally and a thermistor 3 detecting the surface temp. on the heating roller 1, and equipped with a CPU capable of controlling the surface temp. of the heating roller 1, when the surface temp. on the heating roller 1 detected by the thermistor 3 is below 1/3 of the set temp. for fixing T1, to the temp. of fixing set temp. T1×1.1.