Multimotor electronic line shafts for rotary offset printing presses: A revolution in printing machine techniques

In rotary offset printing presses, mechanical line shafts are being replaced by electronic shafts which consist of synchronized position and speed-controlled ac motors driving the complete printing units or single printing cylinders. The dynamic stiffness of the multimotor system to satisfy the requirements of high printing accuracy can be achieved by high-dynamic, cascaded current, speed and position control of the the drives, which can be combined with disturbance observers in critical cases, or by direct drive technology.