Thermostatic device for fuser

摘要

A thermostatic device particularly usable in sensing the surface tempoerature of a rotatable member in a fuser includes a rotatable roller mountable in rolling engagement with a moving surface. A heat sensor located inside the roller senses temperature variations in the roller. For example, a pin that is spring-urged against the inside surface of the roller, moves a switch between open and closed conditions as the inside diameter of the roller varies with a change in its temperature. Alternatively, a bimetallic disc positioned in engagement with the inside surface of the roller is sensed to open or close a switch in response to the roller temperature reaching a given threshold.