| 摘要 |
PURPOSE:To prevent change in image density owing to variable magnification by controlling a phase control angle according to the request for variable magnification of the image as well as to make cost lower and size smaller than a regulator for an exposing lamp by constituting the control device of a microcomputer and simple electrical circuits. CONSTITUTION:A control device for a halogen lamp 2 is constituted of a power source 1, a rectifier circuit 5 for controlling the gate of a triac 3, a trigger element 6, a zero cross circuit A, a circuit B for detecting the operation and execution value for lighting of the lamp 2, a microcomputer 27, a fixing heater 30 and a device 31 for setting magnification, etc. The voltage for lighting the lamp 2 is monitored by the value detected with the circuit B and the phase control angle for the voltage of the power source 1 is controlled by the microcomputer 27 until the voltage for lighting the lamp 2 attains a target value. The variable magnification of the image is set with the device 31 for setting the same and the phase control angle is controlled by the microcomputer 27 according to said magnification. |
