Variable tension controller for rotary printing press

Abstract

Apparatus for controlling the tension of each lead of a multiple lead printing press setup includes a transducer roller interposed in the lead setup to detect the gain (increased tension) in the paper web as it exits from the print cylinder unit. An electronically controlled variable ratio gear assembly is interposed between the drag roller and the drag roller driver shaft. A variable gain tension controller receives the gain signal from the transducer roller and a tachometer signal from the main press drive shaft, as well as a gain setpoint signal. The variable ratio gear assembly includes an harmonic gear assembly and a control motor connected to the harmonic wave generator. The output controller signal of the variable gain tension controller is fed to the control motor to selectively vary the rotational velocity of the wave generator, thereby varying rotational speed of the drag roller and regulating the tension of the paper web. Gain regulation permits the printing setup to operate at a far lower web tension than is possible with prior art systems, and permits the use of a wider range of paper, such as paper having a higher recycled fiber content. Changes in the printing setup which alter the friction applied to the web are compensated automatically, so that web breakage is minimized. The system produces greater throughput, higher productivity, and lower labor costs for setup and operation. Also, each web lead is compensated and regulated individually, so that the web tension at this input to the folder are regulated and optimized for the folder. This factor improves the performance of the folder apparatus.

Dependencies are inferred from the claim text.