| 摘要 |
PURPOSE:To provide an improved inspecting device for printed matter which can cope with an enhancement of the level of a printing press, by providing a signal level holding device for holding the level of a concentration detection signal at a fixed level. CONSTITUTION:A pulse generator 7 detects the rotating frequency of a blanket cylinder 2 in terms of the number of pulses generated per unit time, and a speed converter 8 convers the number of pulses into a printing speed of the press. The fall of the level of the concentration detection signal from a line form camera 5 arising from an increase in the printing speed is held to be constant by increasing the amplification factor of am amplifier 9. Further, a signal processor 6 compares a printed pattern density detection signal from the amplifier 9 with a normal density value prestored in the processor 6, detects quality defects such as scumming, streaks and reversing in the printed matter on the basis of the difference between the signal and the prestored value, and outputs a detection signal and an operating signal for eliminating the cause of the defects. |
