| 摘要 |
PURPOSE:To give an alarm through detecting the dust on the negative plate of photograph, by sweeping the overall face of the negative plate by a coherenet light emitted from a laser apparatus and detecting its reflected light by the photodetector. CONSTITUTION:The laser apparatus 1 is mounted to the frame 6 and the frame 6 is driven on the base plate 7 by the motor 20 in X direction via the roller 8 and also, the plate 7 is driven Y direction by the motor 12 via the roller 10 and these are controlled by the control device 19. Further, a coherent light emitted from the apparatus 1 is bent at a right angle and struck on the negative plate 29 of photograph and sweeps the overall face of said plate and its reflected light is detected by the photodetector 3 provided in the outside of the light locus 2. Accordingly, when the dust exists on the plate 29, its scattered light is incident to the detector 3 and the alarm apparatus 31 can be operated and a good printing can be carried out. |
