Dot Matrix Printers

In the general sense lots of printers count on a matrix of pixels, or dots, that together form the bigger image. However, the term dot matrix printer is particularly used for impact printers that utilize a matrix of small pins to create accurate dots. The advantage of dot-matrix over other effect printers is that they can produce visual images in addition to text; however the text is usually of poorer quality than effect printers that use letterforms (type). Dot-matrix printers can be broadly divided into two major classes:

Ballistic wire printers

Kept energy printers

Dot matrix printers can either be character-based or line-based (that is, a single horizontal series of pixels across the page), describing the configuration of the print head.

At one time, dot matrix printers was among the more typical kinds of printers used for general use, such as for home and small workplace use. Such printers would have either 9 or 24 pins on the print head. 24-pin print heads had the ability to print at a greater quality.

Colour graphics are generally printed in four passes at standard resolution, thus slowing down printing considerably. As a result, colour graphics can take up to four times longer to print than standard monochrome graphics, or up to 8-16 times as long at high resolution mode.

Dot matrix printers are still commonly used in low-cost, low-quality applications like cash registers, or in demanding, very high volume applications like invoice printing. The fact that they use an impact printing method allows them to be used to print multi-part documents using carbonless copy paper, like sales invoices and credit card receipts, whereas other printing methods are unusable with paper of this type. Dot-matrix printers are now (as of 2005) rapidly being superseded even as receipt printers.