| 摘要 |
PURPOSE:To make frame erasing of a reproduced picture image linear and obtain easily visible output image by generating a count signal higher in frequency than synchronizing signals. CONSTITUTION:A scanning beam formed by a polygon mirror 16 is reflected by a mirror 17 and then projected to the light receiving element 12g of a frame erasing circuit 12 through optical fiber 18 and the detection signal BD is given to a counter 12b and CP 11. The counter 12b is reset and counts signals K1 higher in frequency than a clock. When the count value arrived at NS, pulse is supplied from a comparator 12c to FF 12d and setting is performed. The CP 11 image signals to a latch 12a synchronously with the clock, and thereby, a laser light emitting element 14 is made on and off, and a latent image is formed on a photosensitive body 19. When the count value became N, the photosensitive body 19 is irradiated by a beam from the element 14, and frame erasing of the picture image is performed.
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