Fixing device, image forming apparatus, and method of detecting an abnormality of a fixing device

摘要

A fixing device according to this invention includes a heating roller, a heater driver, a thermistor, and a CPU. The heating roller has a heater and heats a recording sheet. The heater driver drives the heater. The thermistor detects a surface temperature of the heating roller. The CPU stops an operation of the heater driver when the surface temperature of the heating roller becomes higher than a predetermined temperature and, thereafter, causes the thermistor to perform detection of the surface temperature of the heating roller for a predetermined time period and issues an alarm about occurrence of a first abnormality when the surface temperature of the heating roller fails to drop in the predetermined time period.