PRINTER SHEET DESKEWING SYSTEM WITH AUTOMATICALLY VARIABLE NUMBERS OF UPSTREAM FEEDING NIP ENGAGEMENTS FOR DIFFERENT SHEET SIZES

摘要

A sheet handling system for a sheet transport path of a reproduction apparatus having a sheet skew correction system being fed image substrate sheets in the process direction by a sheet transport system, wherein it is desired to positively feed and yet effectively deskew a wide range of different lengths of sheets in the process direction. A plurality of identical but independent sheet transport units may be provided spaced along the sheet transport path in the process direction engageable with a sheet being fed through sheet transport path for positively feeding even very short sheets from one sheet transport unit to another and to the skew correction system. Yet these sheet transport units provide independently automatically disengageable nips for automatically releasing even a very long sheet from any unit when that long sheet is in the skew correction system. A different selected number of the sheet transport units are disengaged in response to a different sheet length control signal. A single stepper motor rotating a common camshaft in each unit may be used to reliably lift all the idlers of all the nips to be disengaged.