WETTING WATER DETECTING DEVICE FOR OFFSET ROTARY PRESS

摘要

PROBLEM TO BE SOLVED: To rapidly and accurately detect defective printed matter by providing a light emitting part which emits light to a jet water and a light receiving part which raceives the light transmitted through the water near the injection aperture of a wetting water supply nozzle on an offset rotary press, and detecting the wetting water by a water detecting part based on a signal from the light receiving part. ;SOLUTION: A set of a light emitting part 11 consisting of a modulator 9, a cable 10 and a light emitter 8 and a light receiving part 13 consisting of a light receiver 14, an amplifier and an A/D converter are grouped together. About 95% of the quantity of light emitted to a wetting water from the light emitter 8 is transmitted through the wetting water and the quantity of the received light is measured by the light receiver 14. The light beam emitted by the light emitter 8 is perpendicularly projected to the water level 12 of the wetting water. The light receiver 14 has a photoelectric conversion element and a voltage to be output by the conversion element is amplified by the amplifier, as the voltage is very low. Further, the voltage is subjected to an A/D conversion process. A controller 16 receives an output signal from the light receiving part 13 and a wetting water supply signal to be given to a wetting water supply device 6 and determines whether or not the wetting water is actually supplied.;COPYRIGHT: (C)1997,JPO