Temperature control method for fixing device and image forming apparatus incorporating same

摘要

A temperature control method for use in a fixing device that fixes a toner image on a recording sheet by passing the recording sheet through a fixing nip defined between a fixing member and a pressure member includes temperature detection, heater control, and duty control execution. The temperature detection detects a temperature of the fixing member with a temperature detector. The heater control controls operation of a heater of the fixing device by changing a duty thereof according to the detected temperature. The duty control execution executes a heater duty control to change a heater duty for a current control cycle discontinuously from that for a previous control cycle when the current control cycle precedes entry of the recording sheet into the fixing nip by a given period of time.