How Does a Dot Matrix Printer Work?

Dot matrix printers, also known as impact matrix devices, are an older type of printer that uses an ink-soaked ribbon similar to a typewriter. During the 1970s and 1980s, these devices were the most popular low-cost printing option, but by the mid-1990s, laser and inkjet models had largely replaced them. Dot matrix printers, however, are still in use for some specialty applications as of the date of publication due to their ability to print quickly even on multi-part documents.

Basic Printing Function
Characters are created on paper by striking an inked ribbon with a hard surface in all dot matrix printers. Dot matrix printers, unlike typewriters that use a similar mechanism, do not have fixed character shapes or fonts. Rather, each individual character is created by arranging a series of pins. Dot matrix printers can now be used for basic graphical printing, multiple fonts, and basic text printing – but the printout has a distinctive “dotted” appearance. Dot matrix printouts frequently produce poor-quality text that is difficult to read. Furthermore, dot matrix printers are generally noisier than inkjet or laser models.

Media Types
Most dot matrix printers employ a “daisy-wheel” paper feeding mechanism that necessitates the use of special continuous-feed media with punched holes on the sides. They perform best on uncoated, thin paper. Dot matrix printers, unlike laser or inkjet printers, are suitable for use with multi-part forms such as shipping paperwork and invoices. Because of their impact-based printing capabilities, they can print on all parts of a single form in a single pass.

Dot Size and Pin Density
The number and size of pins in a dot matrix printer’s print head have a significant impact on print quality; even the best dot matrix printers cannot match the quality of inkjet or laser printers. The most basic dot matrix devices use only nine pins to generate each individual character, resulting in a pixelated, blocky appearance. More complex printers employ a greater number of smaller pins, resulting in greater detail and the elimination of the distinctive look of dot matrix text. Dual 9-pin and 24-pin print heads are common configurations for these printers.

Modern Use
Dot matrix printers were phased out of common office and home use as inkjet and laser printers became more reliable and affordable in the early to mid-1990s. They remained popular in businesses that required continuous feed documents or multi-part forms. Due to the low demand for them, dot matrix printers are produced by a relatively small number of manufacturers and have become relatively expensive compared to inkjet and laser printers that offer similar functionality as of the date of publication.