Front lay
A front lay or a front stop is a mechanical assembly that aligns a sheet of paper entering the printing press exactly forwards in the running direction. The leading edge of the sheet hits a stop and tends to bounce back slightly in an uncontrolled manner. In order to compensate for this effect and to bring the sheet into an exact starting position, it is pressed against the stationary front lay by suction or blow nozzles . Another solution to the problem is to pivot a movable front lay slightly against the sheet after it has already struck. For this reason, a distinction is made between stationary and moving front lays. Front brands emerged with the development of cylinder presses at the beginning of the 19th century.
According to the Fogra standard, an accuracy of 0.015 mm is required when aligning the printed sheet . This is necessary in order to register to ensure the following further passages and further processing.
See also
literature
- Helmut Kipphan (Hrsg.): Handbuch der Printmedien. Technologies and production processes. Verlag Springer, Berlin et al. 2000, ISBN 3-540-66941-8 .