METHOD AND DEVICE FOR DETERMINING VARIABLE FACTOR OF PAPER IN PRINTING MACHINE

摘要

PROBLEM TO BE SOLVED: To provide a method and device for determining variable factors of paper in a printing machine configured to enable a user to grasp the cause when a printing failure or paper break of printing paper occurs in the printing machine.SOLUTION: Printing-condition signals such as a print speed signal and a tension signal or the like by a paper feed roller 2 or the like are configured to impart tension to printing paper P running on a printing part 1 and to specify printing conditions for stable running. The printing-condition signals are inputted to a signal processing device 10 so as to transform the signals into power spectra by executing the FFT. An edge sensor 6 arranged on the exit side of the printing part 1 captures displacement of both ends of the printing paper P. A data processing device 12 is inputted with the end information and calculates a change in paper width and a meandering state so as to transform the data into power spectra by executing the FFT. When each variation cycle obtained from the power spectra of the end-information signal of the printing paper matches the variation cycle of any one of the printing-condition signals with each other, it is determined as a variation in factors of the printing machine. In the case other than that, it is determined as a variation in factors of the printing paper.