| 摘要 |
PURPOSE:To hold a photoreceptor at constant temperature and to save electric power by performing full-wave or half-wave feeding to the heater of the photoreceptor or by turning off the heater according to te ambient temperature of the photoreceptor. CONSTITUTION:When the ambient temperature of the photoreceptor drops below 30 deg.C, the outputs of comparators Q1 and Q2 turn on through a thermistor Th, and TRs Q3 and Q4 turn off. A current flows through a resistance R14 and a diode D to turn on both light emission diodes PD1 and PD2, and thyristors PT1 and PT2 both turn on, so that a heater H is driven on full-wave basis. When the ambient temperature is between 30 and 40 deg.C, the comparator Q1 turns off and only the TRQ3 turns on to flow the current through only the diode PD1, driving the heater H on half-wave basis. When the temperature is above 40 deg.C, the comparators Q1 and Q2 both turn off and the heater H is not driven. Thus, the photoreceptor is held at constant temperature and electric power is saved. |
