A printer is a device that produces printed paper output, known in the computer industry as hard copy because it is tangible and permanent. Some printers produce only letters and numbers, whereas others can also produce graphics.

     Letters and numbers are formed by a printer either a solid characters or as dot-matrix characters. Dot-matrix printers create characters in the same way that individuals lights in a pattern spell out words on a basketball scoreboard. Dot-matrix printers constract a character by activating a matrix of pins that produce the shape of the characters. A traditional matrix is five by seven-that is, five dots wide and seven dots high. These printers are sometimes called nine-pin printers, because they have two extra vertical dots for descenders in the lower case letters. The 24-pin dot-matrix printer, which uses a series of overlapping dots, dominates the dot matrix market. The more dots, the better the quality of the characters produced. Some dot-matrix printers can produce colored images.