Abstract: A pair of compensating wheels are carried by a print head carriage in position to ride on record media being printed and are rotatably driven by frictional contact therewith, the wheels having overriding clutches associated with their respective shafts to permit driving of one shaft and its gear in alternate manner with the other shaft and its gear. The respective driving gear engages with a driven gear on a third shaft for rotation thereof and thereby drives the ribbon in one direction. Upon return of the print head carriage in the opposite direction, the action of the overriding clutches is reversed to permit driving of the other shaft while the first shaft and its wheel are free wheeling. Regardless of the direction of travel of the print head carriage, the ribbon drive shaft is rotated in the same direction.