Method for controlling web tension and offset rotary web printing press.

摘要

Press has PLC (50) connected to LAN (40) with drive controller (52) to regulate speed of paper path through cooling unit. PLC is controlled and programmed by external control unit (60), a PC. When press is switched to print operation, PLC sends signal to infeed (12), which has compensating roller, to increase infeed tension. When press returns to non-print mode, web tension is reduced in section between infeed and print units to prevent harm to web in units after the print units.