| 摘要 |
PURPOSE:To improve the thermal efficiency of heater and achieve averaging of the electric energy used by limiting the maximum conduction angle of the supply power to the heat-fixing heater at the operating of an exposure lamp. CONSTITUTION:When copying is started and an exposure lamp P goes ON, a changeover switch SW which had been connected to the contact W2 in order to maintain a heat-fixing heater H at the specified temperature is changed over and connected to the contact W3. As a result, the current supplied to a transistor Tr1 is decreased by a variable resistance R1 and the charging time of a capacitor C becomes long, thus a Triac TRC2 conducts at the firing conduction angle having been set by a current-regulating variable resistance VR1 and capacitor C. Hence, the conduction period of the Triac TRC2 reduces and the temperature of the heater H is controlled to the minimum value for maintaining the specified temperature. This results in improved thermal efficiency through accurate controlling of the temperature of the heater H and averaged power consumption of the copying apparatus. |
