Printer sheet deskewing system with automatic variable nip lateral spacing for different sheet sizes

摘要

A sheet handling system for correcting the skew and/or transverse position of sequential sheets, especially those moving in a process direction in a sheet transport path of a reproduction apparatus to be registered for image printing, of the type in which the deskewing and/or side registration is accomplished by partially rotating the sheet with a transversely spaced pair of differentially driven sheet steering nips. The effective range of sheet size capabilities of such systems may be increased without steering nip slippage or other problems by applying a control signal proportional to the width of the sheet to a system for automatically increasing or decreasing the transverse spacing between the pair of sheet steering nips, so as to provide a much wider spacing for larger sheets yet still be able to handle small sheets. This may be provided as shown by automatically engaging only a selected pair of steering nips out of a selectable plurality of different fixed position sheet steering nips and disengaging the others by lifting their idlers out of the sheet path with cams rotated by a stepper motor with a rotation controlled by the sheet width signal.