| 摘要 |
PURPOSE:To surely detect the defect on the surface of a photosensitive material without generating fogging by the constitution in which the color change of the photosensitive material is detected by a photodetecting part for the visible light to scan the photosensitive material and the rugged defect is detected by a photodetecting part for IR light, respectively. CONSTITUTION:The visible light of a laser light source 10 and the IR light of a laser light source 12 are deflected by a rotary scanner 15 to scan photo graphic paper A on a roll 6. The diffuse reflected light thereof is detected in the photodetecting part 21 and the specular reflected light in the photodetecting part 22, respectively. Since the visible light of 550-635nm wave length is low in spectral photosensitivity, the fogging is not generated even if the defect 9 by the color change of the photographic paper is detected. Since the IR light has high safety of fogging, the S/N of the detection signal is im proved and the influence of noise is eliminated at the time of detecting the rugged defect 11 by using the light having the intensity several tens times the intensity of the light source 10. A filter 23 of the photodetecting part 21 is used to shut off the strong IR light. |
