Unidirectional ribbon drive mechanism

摘要

A ribbon is driven past the printing station of a printer only when the print head is moved in the right-to-left direction across the printer. An endless timing belt causes rotation of a gear pulley that is in mesh with an idler gear. The idler gear is supported on a pair of projecting fingers of a plate that is swingable on the center of the gear pulley. The idler gear is responsive to the direction of rotation of the gear pulley through a drag effect of the projecting fingers with the bottom surface of the idler gear.