(57) A printed matter (4), in which an ink capable of reflecting electromagnetic waves
of wavelengths outside the visible range is used, is irradiated by electromagnetic
radiation from a lamp (8) at least containing said wavelengths outside the visible
range. Light reflected from the irradiated printed matter (4) is coupled to a photoelectric
converter (12), the output of which is taken out through an amplifier (13). The printed
matter (4) is inspected in terms of whether the level of the amplified output is high
or low for a invisible wavelength range.
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