Dot Matrix

Overview

An impact printer that produces characters and graphics through the use of closely spaced pins striking against an ink ribbon aligned over the paper. The first dot matrix printer was introduced in 1970 by Centronics. The TX 80 in 1978 and the MX 80 in 1979 by Epson were the most popular models.

Each pin makes a dot or pixel on impact. The print head containing the pins usually moves across the page from left to right. However, the line matrix printer, a variant of the dot-matrix, would print one whole line of dots. A line of text was built up of lines of dots. The number of pins varied from 9 to 48 with a 48 pin printer producing almost letter like quality. Although, the documents were of an inferior quality than type-based impact printers (such a daisy wheel printer), dot matrix printers were a big hit because they could print graphics and illustrations in addition to text which was not possible with type-based impact printers. Typical speeds of dot matrix printers ranged from 50 to 500 characters per minute - a far cry from today when speed is measured in pages per minute. Today, the main use of dot matrix printers is in legacy systems and cash registers (quality is relatively unimportant for receipts and dot matrix printers can produce carbon copies because it is an impact process which is not possible with inkjet or even laser printers).

picture from: currys.com

Two main sub-classifications of dot matrix printers by the mechanism used are the stored energy printers and ballistic wire printers.