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 A typewriter is a mechanical or electromechanical machine for typing characters. Typically, a typewriter has an array of keys, and each one causes a different single character to be produced on paper by striking an inked ribbon selectivel ...

such as an IBM

Selectric The IBM Selectric typewriter was a highly successful line of electric typewriters introduced by IBM on 31 July 1961. Instead of the "basket" of individual typebars that swung up to strike the ribbon and page in a typical typewriter of the perio ...

. A letter-quality printer operates in much the same fashion as a

. A metal or plastic printwheel embossed with letters, numbers, or symbols strikes an inked ribbon, depositing the ink (or carbon, if an expensive single-strike ribbon was installed) on the page and thus printing a character. Over time, several different technologies were developed including automating ordinary typebar typewriter mechanisms (such as the

Friden Flexowriter The Friden Flexowriter produced by the Friden Calculating Machine Company, was a teleprinter, a heavy-duty electric typewriter capable of being driven not only by a human typing, but also automatically by several methods, including direct atta ...

daisy wheel printer Daisy wheel printing is an impact printing technology invented in 1970 by Andrew Gabor at Diablo Data Systems. It uses interchangeable pre-formed type elements, each with typically 96 glyphs, to generate high-quality output comparable to pr ...

s (dating from a 1939 patent, but brought to life in the 1970s by Diablo engineer David S. Lee) where the type is moulded around the edge of a wheel, and "golf ball" (the popular informal name for "typeball", as used in the

IBM Selectric typewriter The IBM Selectric typewriter was a highly successful line of electric typewriters introduced by IBM on 31 July 1961. Instead of the "basket" of individual typebars that swung up to strike the ribbon and page in a typical typewriter of the peri ...

) printers where the type is distributed over the face of a globe-shaped printhead (including automating IBM Selectric mechanisms such as the

IBM 2741 The IBM 2741 is a printing computer terminal that was introduced in 1965. Compared to the teletypewriter machines that were commonly used as printing terminals at the time, the 2741 offers 50% higher speed, much higher quality printing, quieter op ...

terminal). The daisy wheel and Selectric-based printers offered the advantage that the

typeface A typeface (or font family) is the design of lettering that can include variations in size, weight (e.g. bold), slope (e.g. italic), width (e.g. condensed), and so on. Each of these variations of the typeface is a font. There are thousands o ...

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 (though they were nowhere near the quality of

printing press A printing press is a mechanical device for applying pressure to an inked surface resting upon a print medium (such as paper or cloth), thereby transferring the ink. It marked a dramatic improvement on earlier printing methods in which the ...

es). Most were available either as complete

computer terminal A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. The teletype was an example of an early-day hard-copy terminal and ...

s with keyboards (or with a keyboard add-on option) that could double as a typewriter in stand-alone ("off-line") 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 (unless the programmable microspacing and over-use of the dot were employed), sometimes limited to monochrome, and limited to a fixed set (usually one) of typefaces without operator intervention, though certain font effects like underlining and boldface could be achieved by overstriking. Soon, dot-matrix printers (such as the Oki Microline 84) would offer "Near Letter Quality" (NLQ) 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 (for example

laser printer Laser printing is an electrostatic digital printing process. It produces high-quality text and graphics (and moderate-quality photographs) by repeatedly passing a laser beam back and forth over a negatively-charged cylinder called a "drum" to ...

inkjet printer Inkjet printing is a type of computer printing that recreates a digital image by propelling droplets of ink onto paper and plastic substrates. Inkjet printers were the most commonly used type of printer in 2008, and range from small inexpensi ...

s, and other similar means) have replaced traditional letter-quality printers in most applications. The quality of inkjet printers can approach the old letter-quality impact printers (but can be limited by factors such as paper type).

Use in word processing

Dedicated

word processor A word processor (WP) is a device or computer program that provides for input, editing, formatting, and output of text, often with some additional features. Early word processors were stand-alone devices dedicated to the function, but current ...

s and WP software for general-purpose computers that rose in popularity in the late 1970s and 1980s would use features such as microspacing (usually by 1/120 of an inch horizontally and, possibly, 1/48 of an inch vertically) to implement subscripts, proportional spacing, underlining, and so on. The more rudimentary software packages would implement bold text by overtyping the character in exactly the same spot (for example, using the backspace control code), but better software would print the letter in 3 slightly different positions. Software did exist to (slowly) produce pie charts on such printers (and on some daisywheels the dot was reinforced with metal to cope with extra wear).

References

{{DEFAULTSORT:Letter-Quality Printer Office equipment Computer printers Computer peripherals

Use in word processing

See also

References