Approximate Analysis of Oscillatory Tension Effects on Register Error.

A simple mathematical model of web mass flow through two adjacent printing couples was developed. Computer solutions were generated for assumed oscillatory tension errors at the input to the first couple. These errors may be considered residual effects of out-of-round paper rolls in the presence of a Reel-Tension-Paster or infeed device. Resulting register errors are a function of web modulus of elasticity, press speed,unit-to- unit separation distance, and frequency of disturbance. At certain frequencies, the computed register error is identically zero, and drops sharply with frequency. These data are directly useful as design criteria for tension control systems.