Abstract: The upper reach of a first belt conveyor delivers a stream of partly overlapping sheets to one end of a perforated second belt conveyor whose lower reach is located above the open top of a magazine and below the perforated bottom wall of a suction chamber. The lower reach attracts the non-overlapped leaders of successive foremost sheets of the stream and transports them toward a position of register with the open top of the magazine. Timely separation of sheets which are attracted to the underside of the lower reach is insured by a non-foraminous slide which is installed between the suction chamber and the lower reach and is movable lengthwise of the lower reach to seal a selected number of perforations in the lower reach in the region of that side wall of the magazine which is remote from the first conveyor.