Heater controlling apparatus and a fixing apparatus of an electrophotographic apparatus in use therewith

A fixing unit for printers and copiers includes: a heater (4), adapted in the fixing unit, for heating a fixing member to fix a toner image on a sheet; a zero-cross detector (5) for detecting zero-cross timing of voltage of electric power supply (1); a switching circuit (2,3) for turning on and off the electric power to the heater; a controller (9) for controlling the switching operation of the circuit so as to provide a first state that the electric power is continuously supplied to the heater (4) from a zero-cross point to other zero-cross point and a second state that the electric power is not supplied to the heater from a zero-cross point to other zero-cross point. In the fixing unit, the electric power is supplied to the heater with a intermittent pattern, including the second state, for a predetermined period after at least one of a turn-on operation of the heater and a turn-off operation of the heater.