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Dot Matrix Printer
Rudolf Hell (1901–2002), Fritz Karl Preikschat (1910–1994)
Dot matrix printers use a cluster of closely spaced dots to form individual letters. Each dot is controllable by the printer, making it possible for the printers to produce text in any typestyle and at any size; they can also construct elaborate graphics. In contrast, other contemporary printers, such as computerized electric typewriters and typeball and “daisy wheel” printers, all stamped letters wholly formed from a die.
To create the dots, small metal pins or rods are mechanically pushed forward against an ink-soaked ribbon or fabric that makes physical contact with the paper. Tiny electromagnets called solenoids power the forward motion of the pins against a guide plate with tiny holes to help steer the pins to the appropriate place. The print quality of dot matrix printers depends heavily on the number of pins used to transfer the image, which is typically 7 to 24, for maximum resolution around 240 dots per inch (dpi). Speeds range from 50 to 500 characters per second (cps).
The birth of the modern dot matrix printer is generally understood to have occurred in Japan in 1968 with the introduction of the Shinshu Seiki company’s EP-101 (later EPSON®) and OKI Data Corporation’s Wiredot printer that same year. Earlier devices, such as Rudolf Hell’s 1929 Hellschreiber teletypewriter, sent the raw collection of dots from one machine to the other and are more properly thought of as facsimile machines.
Dot matrix printers were as popular with businesses as they were in the home office. Because they made their print with mechanical pressure, they could easily print on multipart forms, simultaneously creating two or more copies, making them fixtures at car-rental kiosks, where they were commonly used to print rental contracts.
Electrostatic discharge printers (which print on silver paper), thermal printers (typically used for credit card receipts), and inkjet printers are all fundamentally dot matrix printers, but with different kinds of mechanisms to transfer the dots to the paper. Even 3-D printers can be thought of as a special kind of dot matrix printer that prints a single dot of material at a time.
In 2013, the Wiredot printer received the Information Processing Technology Heritage award from the Information Processing Society of Japan.
SEE ALSO Laser Printer (1971), 3-D Printing (1983)
Wiredot printer, manufactured by the OKI Electric Industry Co., Ltd., 1968.