Abstract: An improved, low cost, high speed, impact printing apparatus usable as a typewriter or as a machine printer is disclosed which includes a carriage translatable along a page through a rack and gear assembly and having an electronically controlled printing unit oriented to reveal the line of write and give constant printing characteristics independent of carriage speed. The printing unit includes a thin, lightweight, circular, bidirectionally shiftable, distensible synthetic resin band having printing characters thereon, along with a single, spring-powered impression hammer for selectively engaging and distending the band toward the page in order to print a selected character. Printing and letter-spacing are concurrently initiated and accomplished using only a single, windable, energy-storing mainspring and a mechanical energy transmission assembly coupling the rack and gear assembly and printer in parallel.