Examples of impact printers include dot-matrix printers, drum printers, line printers, daisy-wheel printers, band printers and chain printers. An impact printer functions by striking a pin on the surface of an inked ribbon. The ink ribbon is pressed against a paper to form a print image.
Impact printers are useful and beneficial in environments where low-cost printing is essential. Although, impact printers are generally noisy, they are ideal for printing multipart forms, because they are capable of printing through many layers of paper with ease. Another advantage of an impact printer is that it produces a near letter quality (NLQ) print only, which is suitable for printing envelopes, invoices or mailing labels.
However, impact printers have certain disadvantages. Apart for being noisy, impact printers do not produce high-quality images, and their quality of print is not as good as that of inkjet or laser printers. Moreover, they are slow compared to laser printers.
The chain and band types of impact printers are faster than the dot-matrix printer; however, they are more expensive and equally loud as the dot-matrix printer. The daisy-wheel impact printer produces high-quality prints compared to the dot-matrix printer; however, it is quite slow.
In terms of cost, the dot-matrix printer is the best, as long as print quality is not much of an issue.