Print head

Impact printers

Impact printers rely on a forcible impact to transfer ink to the media. The impact printer uses a print head that either hits the surface of the ink ribbon, pressing the ink ribbon against the paper (similar to the action of a typewriter), or, less commonly, hits the back of the paper, pressing the paper against the ink ribbon (the IBM 1403 for example). All but the dot matrix printer rely on the use of fully formed characters, letterforms that represent each of the characters that the printer was capable of printing. In addition, most of these printers were limited to monochrome, or sometimes two-color, printing in a single typeface at one time, although bolding and underlining of text could be done by "overstriking", that is, printing two or more impressions either in the same character position or slightly offset. Impact printers varieties include typewriter-derived printers, teletypewriter-derived printers, daisywheel printers, dot matrix printers, and line printers. Dot-matrix printers remain in common use in businesses where multi-part forms are printed. An overview of impact printing contains a detailed description of many of the technologies used.