An improved tape applicator for apply a tape to close a case or box is provided that uses a wiper system that better seals the tape to the box, provides an improved cut-off system wherein the action of the cut-off blade which partially cuts and then tears the tape is across the tape path at an improved angle. Also included is an improved system for adjusting tab length on the lead end of the case, providing a stiffened free end portion of the tape to engage an on-coming case, for controlling the rotation of large tape rolls by applying pressure to the side of a large roll and locking the tape roll to the mounting hub on the machine by penetrating the tape roll core with locking elements.