Abstract: A continuous motion ribbon imprinter moves with and marks a moving web on a packaging machine and has an easily set control adjusting step-by-step advance of the ribbon across the type block to accommodate wide variations in the size of the printed indicia so as to always present just enough length of fresh ribbon to cover the type for the next imprint. A frame mounting the type block and ribbon reels swings in either a clockwise or counterclockwise orbital path having a dwell stroke on the moving web, and a lift stroke spacing the ribbon from the web. The ribbon remains stationary on the type block during the dwell stroke and is advanced across the type block on the lift stroke. A single input shaft drives the frame through its orbital path and also drives the mechanism for unwinding the fresh ribbon from one reel and winding the spent ribbon on a second reel.