| 摘要 |
PURPOSE:To always keep the temperature of a fixing part of a copying machine, the temperature of a photosensitive drum and the light quantity of an exposure lamp at a fixed level respectively regardless of the waveform of a power supply, by giving quick compensation to the control volume of load with the variation of power supply voltage, etc. CONSTITUTION:An applied voltage detecting circuit for exposure voltage, a thermistor for detection of fixing temperature and humidity, a zero cross circuit for waveform of power supply, etc. are connected to the input port of a microcomputer. A commerical power supply and a fixing heater to be controlled are connected in series to a TRIAC21. While a commercial power supply and an exposure lamp to be controlled are connected in series to a TRIAC22. Furthermore a commercial power supply and a photosensitive drum heater are connected in series to a solid state relay 31. Here the microcomputer controls the conduction phase of each waveform to the exposure lamp and controls the conduction at the zero cross point of each waveform to the fixing heater. Thus it is possible to always keep the load power at a fixed level regardless of the waveform of power supply. |
