Ceramic heater roller with zone heating

摘要

A thermal conductive roller for use in copying machines, steam-heated and induction-heated applications includes a ceramic heating layer formed by plasma spraying a ceramic material. Conductive bands are provided for supplying electrical current to portions of the ceramic heating layer. In one embodiment, heat is generated by passing current through a length of the roller between two narrow bands. In a second embodiment, heat is generated by directing current radially from the core of the roller to an outer ground layer through wide bands corresponding to heating zones for the roller. In a third embodiment, the ceramic layer is inside the steel core.