Electric power control device for a fixing heater

摘要

The invention relates to an electric power control device usable with both 50Hz and 60Hz AC voltage sources (1), comprising control signal generating means (CPU1,TH) for generating a control signal (FSRD) having different levels at predetermined periodic intervals T; switching means (3,Q2) for switching electric power supply (1) to a load (2,R3) from an AC voltage source (1) in a period starting at zero-cross timing to next zero-cross timing in accordance with the level of the control signal (FSRD) at the first mentioned zero-cross timing; where the periodic intervals T may change in accordance with the frequency of the AC voltage source.