DEVICE FOR MONITORING SHEET MOVEMENT NEAR THE LAY MARKS OF SHEET-FED OFFSET PRINTING PRESSES

摘要

A device for monitoring sheet movement near the lay marks of sheet-fed offset printing presses. To ensure that a sheet has sufficient time to settle on the lay marks, the invention automatically selects between two instants at which sheet position is detected based on the state of the press (printing on or printing off). Since, depending on the state of the press, different procedures are performed before printing, selection of different instants of sensing provide a sheet the maximum amount of time possible for settling before detection.