Patent ID: 6168153
Filing Date: 2001-01-02
Classification: B65H,G03G

Abstract:
In a sheet handling method for correcting the skew of sequential image substrate sheets to be moved downstream in a process direction in a sheet transport path for a reproduction apparatus, in which selected said image substrate sheets are deskewed by being partially rotated by a sheet deskewing system, the improvement for increasing the operative range of effective deskewing of image substrate sheets of different lengths in said process direction, from a preset short sheet length to a very much greater sheet length, comprising: obtaining a control signal proportional to said sheet length in said process direction of an image substrate sheet in said sheet transport path, providing a plurality of spaced apart sheet feeding nip sets of plural sheet feeding nips upstream from said sheet deskewing system in said sheet transport path, said plurality of spaced apart sheet feeding nip sets being spaced apart from one another and from said sheet deskewing system in said process direction by less than said preset short sheet length so as to be capable of providing positive sheet feeding of said preset short sheet lengths as well as longer sheet lengths in said process direction, sequentially positively feeding all of said image substrate sheets in said process direction downstream in said sheet transport path into said sheet deskewing system with said plurality of spaced apart sheet feeding nip sets, said plurality of spaced apart sheet feeding nip sets being selectably individually disengageable from an image substrate sheet moving in said process direction in said sheet transport path by opening said sheet feeding nips thereof, and automatically disengaging a selected plural number of said plurality of spaced apart upstream sheet feeding nip sets in response to said control signal proportional to said sheet length of said image substrate sheet moving in said process direction in said sheet transport path when said image substrate sheet is in said sheet deskewing system and before said image substrate sheet is deskewed by being partially rotated by said sheet deskewing system so that said upstream sheet feeding nip sets are disengaged from said image substrate sheet as said image substrate sheet is being deskewed, even for an image substrate sheet of said much greater sheet length, while a subsequent image substrate sheet moving in said process direction in said sheet transport path may be positively fed by at least one of said plurality of spaced apart sheet feeding nip sets.