Patent ID: 6817609
Filing Date: 2004-11-16
Classification: B65H

Abstract:
A printing system having a sheet transport system for moving print media sheets in a process direction from upstream to downstream in a sheet transport path, and a sheet lateral registration system in said sheet transport path downstream of said sheet transport system providing for movement of said sheets laterally of said process direction,wherein said print media sheets have a wide range of different sheet dimensions in said process direction to be accommodated by said sheet lateral registration system, wherein said sheet transport system comprises a plurality of sheet transport units having sheet feeding nips, said sheet transport units being spaced from one another and from said sheet lateral registration system from upstream to downstream in said process direction along said sheet transport path, each of said sheet transport units having sheet feed rollers providing said sheet feeding nips and a drive system for rotationally driving said sheet feed rollers in said process direction, said sheet feeding nips of said plurality of sheet transport units being engageable with a sheet being fed in said process direction in said sheet transport path for positively feeding said sheet downstream in said sheet transport path from one said sheet transport unit to another said sheet transport unit and from a downstream one of said sheet transport units to said sheet lateral registration system, each of said plurality of sheet transport units being selectably independently operable by rotation of said sheet feed rollers in said same process direction by said drive system thereof to release said sheet by opening said sheet feeding nips thereof and to positively engage said sheet for feeding said sheet downstream by closing said sheet feeding nips thereof; a sheet length signaling system providing a sheet length control signal proportional to said variable dimension of said sheet in said sheet transport path, a control system for automatically so operating a selected plurality of said sheet transport units by opening said sheet feeding nips thereof in response to said sheet length control signal when said sheet is in said sheet lateral registration system, said sheet feed rollers of said plural sheet transport units having at least two different circumferential lengths of at least two different roller radii, comprising first and larger circumferential lengths with larger radii and second and smaller circumferential lengths with smaller radii, said control system providing selective rotations of said sheet feed rollers of selected said sheet transport units to selectively provide, by selected partial rotations of said sheet feed rollers, a first operating mode of closed sheet feeding nips with said first and larger circumferential lengths with larger radii, and a second operating mode with said second and smaller circumferential lengths with smaller radii to provide open nips for said selected sheet transport units providing unobstructed sheet lateral movement therein by said sheet lateral registration system.