Abstract: A method and apparatus for locking the drive hubs of a forms overlay station in a laser electrographic printer to its transparent forms overlay drum includes counterboring a plurality of holes through the drum into the hubs, inserting a resilient member such as an O-ring into each counterbored hole, and compressing the resilient member to form an interference fit among the compressed resilient member and an interface formed within the counterbored hole by the drum and hubs.

Abstract: This invention relates to a system for positioning a high-speed endless loop printing band of the type used on impact band printers. The band positioning apparatus includes a first sensor for being placed adjacent the edge of the endless loop band for detecting the drift of the edge to one side of a reference line. A second sensor is provided adjacent an area of the endless loop printing band for detecting the drift of the edge to the other side of the reference line. A microprocessor is coupled to the first and second sensors for generating a correcting output signal to a step motor. The step motor is coupled to a pulley in guiding communication with the endless loop printing band for displacing the pulley toward the reference line, thereby correcting the undesired movement of the edge of the endless loop printing band.