The first generation of dot matrix printers used a grid of nine pins to create each character. The print quality from these models is acceptable, but certainly not impressive.

As dot matrix printers began to compete with daisy wheel printers and the first laser printers, firms introduced 24-pin models. By more than doubling the number of pins, printed documents approached typewriter quality.

Today, however, the tide has shifted back to 9-pin designs. Although 24-pin models offer high-quality images, they tend to be slower and more expensive than 9-pin models. In most cases, documents printed on dot matrix printers do not need to offer exceptionally high quality, so 9-pin models do just fine.

There is very little quality difference between 9-pin and 24-pin models if the documents will be printed in draft mode.