Ribbon drive arrangement for a printer

摘要

Apparatus for advancing equal increments of tape to a takeup reel utilizes a drive blade having an edge that tends to slip in one longitudinal direction and grip in the other. Reciprocation of the drive blade at the circumference of the accumulated tape results in incremental tape movements in the direction corresponding to gripping of the drive edge. For a preferred implementation, the drive edge has the contour of an involute. By so contouring the drive blade, the engagement at the tape circumference is essentially tangential for a broad range of diameters of the accumulated tape.