Abstract: A system for stacking, registering and fastening printed sheets fed from a reproduction apparatus onto a compiler or other stacking tray, with a plural component vertically extending but laterally movable sheet stacking edge registration system adjacent at least one edge of the stacking tray and a set stapling system movable parallel to the edge registration position to fasten the stack of sheets edge registered in the tray in plural different fastening positions; the edge registration system being movable to provide continuous stapling access therethrough by the set fastening system. The edge registration system is automatically movable in coordination with the stapling system to stay out of its path yet maintain registration of the stack of sheets in the tray at the same edge registration position.