Fuser device

A fuser device, comprising:

• a fixation heater configured to heat a specific part with resistance heating;
• a temperature sensor configured to detect as a detection temperature a temperature of the specific part;
• an alternating current switching unit configured to turn on and off alternating current power supply to the fixation heater;
• a controller configured to control the alternating current switching unit with a heater control signal and thereby perform temperature control of the fixation heater;
• an estimation calculating unit configured to derive an estimation temperature at a second time point on the basis of the detection temperature at a first time point and the heater control signal until the second time point, the second time point being a time point when a predetermined time elapses from the first time point;
• and
• an anomaly detecting unit configured to detect anomaly on the basis of the detection temperature at the second time point and the estimation temperature at the second time point.