| 摘要 |
PURPOSE:To obtain invariably constant image density even if the density of an original varies by using a microcomputer to store the original density previously, and controlling the phase control angle of the source voltage of an exposure lamp according to the original density. CONSTITUTION:The controller for the halogen lamp 2 consists of a power source 1, photodetecting element 36, 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. This device is equipped with the circuit B and photodetecting element 36 which detects the original density by scanning of the lamp 2. Then, the phase control angle of the voltage of the power source 1 of the lamp 2 is controlled by the microcomputer 27 on the basis of the output value of the circuit B and the detected value of the element 36. |
