Apparatus and method for controlling the positioning of marking elements in a serial impact printer.

摘要

A serial impact printer including a single cam member (74) for properly establishing and maintaining the throat gap distance between a character imprinting surface (52) and the platen (10) at a print point and for raising and lowering a selected ribbon (64) or (66), of a composite marking/correcting ribbon pack assembly (58), to and from the print point. A short throat gap distance is needed for commercially acceptable printing speeds in this high hammer mass printer, and is needed for high quality printing; conversely, a long throat gap distance is needed for print point visibility at all other times. The cam member has plural camming tracks (84, 86) and surfaces (88) which coordinate ribbon position with throat gap distance.