Printer sheet lateral registration system with automatic upstream nip disengagements for different sheet size

摘要

A sheet registration system for a sheet transport path of a reproduction apparatus providing positive feeding yet lateral registration of a wide range of different image substrate sheets. Independent sheet transport units with plural radius sheet feed rollers spaced along the sheet transport path engage sheets being fed to provide positive feeding of even very short sheets from one sheet transport unit to another, yet provide automatic opening of the nips of selected units to allow lateral registration movement of even a very long sheet in the downstream lateral sheet registration system. The same drive motor rotatably driving each sheet transport unit is controlled in rotational position to selectively open the number of open sheet feeding nips needed for the lateral registration movement of that particular sheet length. The mating idlers for the sheet feed rollers need not be moved to open the nips.