Fixing device, fixing device control method, and image forming apparatus

摘要

A fixing device includes a rotatable fuser member (1), a rotatable pressure member (2), a heater (5), a rotary driver, a thermometer (7), and a controller (10). The rotatable fuser member is subjected to heating. The rotatable pressure member is disposed opposite the fuser member. The heater heats the fuser member. The rotary driver imparts torque to at least one of the fuser and pressure members. The fuser member and the pressure member are pressed against each other to form a fixing nip therebetween. The thermometer is disposed external to the fixing nip to detect a temperature outside the fixing nip. The controller is operatively connected with the thermometer to control an amount of heat applied to the recording medium through the fixing nip according to the detected temperature, so that the recording medium exhibits a substantially constant post-fixing temperature downstream from the fixing nip.