A computer output device that produces a line of print per cycle of its operation. The number of character positions in a line generally ranges from 80 to 160, and lines are printed at rates from 150 to 3000 lines per minute. A complete line of information has to be assembled in a buffer memory within the machine before it can start printing. When a line of print has been completed a paper-feed system moves the paper so that the position for the next line of print is opposite the printing mechanism. The paper to be printed is usually supplied as a continuous web of up to 2000 forms divided by perforations. To ensure positive control of the forms, the margins are punched with holes that engage on the tractors of the printer’s paper-feed system.

Although line printers have been superseded by page printers for many applications, they are still more efficient for high-volume jobs where a high print quality is not needed. See also band printer.