| 摘要 |
PURPOSE:To suppress variation in the turn-on voltage of an exposure lamp due to asymmetric distortion of a positive and a negative half wave of a source voltage by selecting the positive or negative half wave and switching on or off a fixing heater. CONSTITUTION:The controller for the halogen lamp 2 consists of a power source 1, gate control rectifying circuit 5 for a triac 3, trigger element 6, zero- cross circuit A, detecting circuit B for the lighting operation and effective value of the lamp 2, microcomputer 27, fixing heater 30, magnification setter 31, etc. The turn-on voltage of the lamp 2 is controlled by the microcomputer 27. The positive or negative half-wave cycle of the voltage of the power source 1 when the lamp 2 is turned on is selected to start switching on or off the heater 30 at the time of the selected half wave. |
