| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a voltage detection apparatus which has a power shutoff means independently of a power control means and which saves energy in a state where no power is supplied to a control load by turning off the power supply to a zero-cross detection circuit at the same time that the power shutoff means shuts off; a heating device; and an image forming device. <P>SOLUTION: The voltage detection apparatus has triacs 4, 13 for supplying an AC power supply 1 to a ceramic surface heater 24; a relay 41 for passing or shutting off power supplied to the ceramic surface heater 24; and a zero-cross detection circuit 12 for detecting the zero-cross point of the AC power supply 1. An engine controller 11 controls the triacs 4, 13 based on pulse signals from the zero-cross detection circuit 12; controls the relay 41 via the transistor 42 to pass or shut off the power according to preset conditions; and has a photocoupler 55 arranged in series with the transistor 42 for detecting the on/off action of the transistor 42 to pass or shut off the power supplied to the zero-cross detection circuit 12. <P>COPYRIGHT: (C)2008,JPO&INPIT |
