Electrophotographic apparatus comprising improved thermal fixing means

Claim 1

An electrophotographic apparatus comprising: electric heater means for thermally fixing a toner image to a copy sheet; power source means operative to supply full electric power and partial electric power to the heater means; and switch means connected to the power source means and the heater means for controlling the power source means to normally supply partial power to the heater means and to supply full power to the heater means for a predetermined length of time as the copy sheet passes through the heater means; the switch means being constructed to sense passage of the copy sheet through the heater means; the switch means comprising a first switch provided at an inlet of the heater means which is actuated by engagement with the copy sheet and a second switch provided at an outlet of the heater means which is actuated by engagement with the copy sheet; the first switch controlling the power source means to switch from partial power to full power and the second switch controlling the power source means to switch from full power to partial power; the switch means further comprising a third switch provided between the inlet of the heater means and the first switch which is actuated by engagement with the copy sheet and means for selectively enabling the first and third switches during a single copy operation and a multiple copy operation respectively.