| 摘要 |
PURPOSE:To measure the film thickness of the ink stuck at various positions by correcting the first signal with the second signal to obtain the ink film thickness. CONSTITUTION:The scattered light from an ink-stuck face is detected by RGB color sensors 25, the noise by the disturbance light is removed when the signal is fed through a band-pass filter 26 with the same frequency as that of modulated light, and only the signal is extracted. The G sensor 25b becomes a main color sensor and the B color sensor 25c becomes a complementary color sensor for the yellow ink to be used, for example. The signal (first signal) obtained from the main color sensor 25b and the signal (second signal) obtained from the complementary color sensor 25c are sent to an arithmetic unit 27, and the second signal is subtracted from the first signal for correction. The effect of the disturbance light is eliminated, the effect of the ink surface shape an backing surface is eliminated, the signal corresponding to only the ink film thickness is obtained, and the ink film thickness is measured. |
