The dot matrix works much like a typewriter does to print an image on the page. A typewriter prints an image when a hammer strikes a ribbon which hits the page. A dot matrix printer prints an image when combinations of pins in the print head strike a ribbon which hits the page. These pins move together to form different letters and symbols.
The number of pins in the print head determine the quality of the print. The more pins in the print head, the better the print. The most common include a 9-pin and 24-pin.
Regardless of the number of pins, these printers can print in two modes: draft or near letter quality or NLQ mode. Draft mode produces a poor quality print, but is faster. Near letter quality mode produces print that can compare to the print that comes out of a high quality typewriter. However, it takes longer to print.
Some dot matrix printers can print in color. Others are color capable which means you can upgrade them to color at a later time. Although these printers do not produce as vibrant of colors as other types of printers, they could be a low-cost alternative.
The speed of dot matrix is measured in characters per second or Cps. Depending upon the printer, this can be from 50 to 700.
Dot matrix printers are usually the least expensive. Although very popular years ago, they are not used much today. They do not produce a high print quality, are slow, and noisy. However, they are cheap to operate and do come in handy if you need to print on a multiple copy form.