| 摘要 |
An inspection apparatus (40) for a sheet of paper (W) subjected to a process to impart a translucent property such as a "watermark" or a "security window" includes: an inspection cylinder (45) in which a surface facing the sheet of paper (W) is provided with a luminescence-producing portion (45a); UV-LED illuminators (41a, 41b) which irradiate the sheet of paper (W) with light containing the ultraviolet rays; a color camera (42) which images the sheet of paper (W); an ultraviolet cut filter (43) which eliminates the ultraviolet rays in the light emitted from the UV-LED illuminators (41a, 41b) and reflected off the sheet of paper (W) as well as the luminescence-producing portion (45a) and makes only the light having wavelengths longer than wavelengths of the ultraviolet rays incident on the color camera (42); and a control device (46) which determines appropriateness of a processed portion (PE) on the sheet of paper (W) having the translucent property on the basis of luminescence in a visible light range produced by the luminescence-producing portion (45a) and made incident on the color camera (42). |
