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Daisy wheel printing is an impact printing technology invented in 1969 by David S. Lee at Diablo Data Systems. It uses interchangeable pre-formed type elements, each with typically 96 glyphs, to generate high-quality output comparable to premium typewriters such as the IBM Selectric, but two to three times faster. Daisy wheel printing was used in electronic typewriters, word processors and computers from 1972. The daisy wheel is considered to be so named because of its resemblance to the daisy flower. By 1980 daisy wheel printers had become the dominant technology for high-quality print. Dot-matrix impact, thermal, or line printers were used where higher speed was required and poor print quality was acceptable. Both technologies were rapidly superseded for most purposes when dot-based printers—in particular laser printers—that could print any characters or graphics rather than being restricted to a limited character set became able to produce output of comparable quality. Daisy wheel technology is now found only in some electronic typewriters. == History == A. H. Reiber of Teletype Corporation received U.S. Patent 2,146,380 in 1939 for a daisy wheel printer. With its dependence on the mechanical technology of the day it was not considered worthwhile to put into production. In 1972 a team at Diablo Systems led by engineer David S. Lee developed the first commercially successful daisy wheel printer, a device that was faster and more flexible than IBM's golf-ball devices, being capable of 30 cps (characters per second), whereas IBM's Selectric operated at 13.4 cps. Xerox acquired Diablo that same year, following which Lee departed to set up Qume Corporation in 1973. Xerox's Office Product Division had already been buying Diablo printers for its Redactron text editors. After 7 years trying to make Diablo profitable, the OPD focused on developing and selling the Diablo 630 which was mostly bought by companies such as Digital Equipment Corporation. The Diablo 630 could produce letter quality output as good as that produced by an IBM Selectric or Selectric-based printer, but at a lower cost. A further advantage was that it supported the entire ASCII printing character set. Its servo-controlled carriage also permitted the use of proportional spaced fonts, where characters occupy a different amount of horizontal space according to their width. The Diablo 630 was so successful that virtually all later daisy wheel printers, as well as many dot matrix printers and even the original Apple Laserwriter either copied its command set or could emulate one. Daisy wheel printers from Diablo and Lee's 1973 company Qume were the dominant high-end output technology for computer and office automation applications by 1980, though high speed non-impact techniques were already entering the market (e.g. IBM 6640 inkjet, Xerox 2700 and IBM 6670 laser). From 1981 onwards the IBM PC's introduction of "Code page 437" with 254 printable glyphs (including 40 shapes specifically for drawing forms), and development of Xerox Star-influenced environments such as the Macintosh, GEM and Windows made bit-mapped approaches more desirable, driving cost reductions for laser printing and higher resolution for impact dot matrix printing. Xerox later adapted Diablo's daisy wheel technology into a typewriter that sold for less than $50. An automated factory was built near Dallas that took less than 30 minutes to assemble a Xerox typewriter. The Xerox typewriter was well received but never achieved the projected sales numbers due to the advent of the PC and word processing software. The typewriter was later modified to be compatible with PCs but the engineering which made it a low cost device reduced its flexibility. By the mid-1980s daisy wheel technology was rapidly becoming obsolete due to the growing spread of affordable laser and inkjet machines, and daisy wheel machines soon disappeared except for the small remaining typewriter market. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Daisy wheel printing」の詳細全文を読む スポンサード リンク
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