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 reproductionapparatus having a sheet skew correction system being fed image substratesheetsin the process direction by a sheet transport system, wherein it is desired topositivelyfeed and yet effectively deskew a wide range of different lengths of sheets intheprocess direction. A plurality of identical but independent sheet transportunits maybe provided spaced along the sheet transport path in the process directionengageable with a sheet being fed through sheet transport path for positivelyfeedingeven very short sheets from one sheet transport unit to another and to theskewcorrection system. Yet these sheet transport units provide independentlyautomatically disengageable nips for automatically releasing even a very longsheetfrom any unit when that long sheet is in the skew correction system. Adifferentselected number of the sheet transport units are disengaged in response to adifferent sheet length control signal. A single stepper motor rotating acommoncamshaft in each unit may be used to reliably lift all the idlers of all thenips to bedisengaged.