Drum clamping mechanism for a printer

摘要

A mechanism for clamping the leading edge of a sheet to be wrapped around a printing drum for printing in a plurality of colors includes a clip that is movably mounted in the drum so that it can be moved between an open position and a clamping position, the clip being biased to its clamping position. One or more deflectable cams are positioned adjacent to the drum for engagement by the clip. When the drum is rotated in its direction for printing successive colors on the sheet, the clip deflects the cam and remains in its clamping position. However, when the drum is rotated in the opposite direction to discharge a printed sheet, the clip is engaged by the cams and wedged thereby to its open position thereby releasing the printed sheet. The mechanism also includes provision for automatically discharging the printed sheet from the drum to a discharge path adjacent to the drum when the clip is opened.