| 摘要 |
PURPOSE:To hold a light quantity within the unit time of a light source always at a regulated level by always observing the light quantity in the light source, and controlling the number of pulses generated at a pulse generating means which generates the pulse to illuminate the light source at every scanning of a photoelectric converter with a signal synchronized with the scanning of the photoelectric converter. CONSTITUTION:The light quantity in a fluorescent lamp 1 is received with a photodetector 7, such as a photocell, etc., and is converted to an electrical signal, and the signal is sent to a light receiving circuit 8. A light quantity feedback circuit 9, by controlling the on and off times of a switching circuit 5 corresponding to the output of the light receiving circuit 8, controls the light quantity in the fluorescent lamp 1 within one scanning time of a line sensor 2 so as to hold always a regulated level. At such a time, an illumination circuit 6 performs the high frequency illumination of the fluorescent lamp 1 with a synchronous or an asynchronous signal in the scanning time of the line sensor 2.
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