摘要 |
In a laser beam scanner of used for exposing a latent image on a photographic paper, intensities of the laser beams are maintained in predetermined range by compensating amplitude of driving signals supplied to acousto-optic modulators when intensities of the laser beams emitted from laser light sources are varied. The intensities of the laser beams passing through the modulators are sensed by photo sensors and compared with predetermined standard value. When any of the intensity of the laser beam is discrepant from the standard value, a difference between them is calculated and an optical modulation data for controlling the amplitude of the driving signal is compensated by subtracting the difference value from the standard value. Thereby, the amplitude of the driving signal of the modulator is compensated.
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