Letter-quality printer
A letter-quality printer was a form of computer impact printer that was able to print with the quality typically expected from a business typewriter such as an IBM Selectric.
A letter-quality printer operates in much the same fashion as a typewriter. A metal or plastic printwheel embossed with letters, numbers, or symbols strikes an inked ribbon, depositing the ink on the page and thus printing a character.
Over time, several different technologies were developed including automating ordinary typebar typewriter mechanisms, daisy wheel printers where the type is moulded around the edge of a wheel, and "golf ball" printers where the type is distributed over the face of a globe-shaped printhead. The daisy wheel and Selectric-based printers offered the advantage that the typeface was readily changeable by the user to accommodate varying needs.
These printers were referred to as "letter-quality printers" during their heyday, and could produce text which was as clear and crisp as a typewriter. Most were available either as complete computer terminals with keyboards that could double as a typewriter in stand-alone mode, or as print-only devices. Because of its low cost at the time, the daisy wheel printer became the most successful, the method used by Diablo, Qume, Brother and Apple.
Letter-quality impact printers, however, were slow, noisy, incapable of printing graphics or images, sometimes limited to monochrome, and limited to a fixed set of typefaces without operator intervention, though certain font effects like underlining and boldface could be achieved by overstriking. Soon, dot-matrix printers would offer "Near Letter Quality" modes which were much faster than daisy-wheel printers, could produce graphics well, but were still very noticeably lower than "letter quality". Nowadays, printers using non-impact printing have replaced traditional letter-quality printers in most applications. The quality of inkjet printers can approach the old letter-quality impact printers.