A line matrix printer is a computer printer that is a compromise between a lineprinter and a dot matrix printer. Basically, it prints a page-wide line of dots. It builds up a line of text by printing lines of dots.
Robert A. Kleist and business partner Gordon Barrus created the line matrix printer in 1974, and founded Printronix Inc. They envisioned a new type of printer that would be faster, more reliable and less costly than the cumbersome character printers on the market at the time. The line matrix printing incorporated a unique shuttle-based technology that laid down a matrix of dots and print bar codes and graphics as well as the usual characters. Working out of a garage in Playa Del Ray, Calif., the Printronix team developed a revolutionary 300-line-per-minute (LPM) prototype line matrix printer in just 90 days. Printronix introduced this line matrix printer, called the P300 series, in 1974.
Line printers are often used for printing box labels as well as invoices and reports. They print as rapidly as slow lineprinters, and can print bar codes and other graphics as well. When implemented as impact printers, they can be the least expensive to operate, per page.
There are numerous mechanisms. One of the most successful is to use a reliable stored energy printer arranged as a comb, and then move the comb back and forth. The forward and backward motion is called shuttling, hence products are often referred to as "shuttle matrix".
Speeds increased with products from manufacturer TallyGenicom formerly Tally with the first 1,400 LPM machines. This was followed by an 1,800 LPM printer which used a newly invented dual hammerbank system where odd and even lines were printed by separate hammerbanks. Dual hammerbank machines however suffer from un-even performance and print quality, and the design was abandoned, replaced by a single hammerbank 1800 LPM model, the T6218.
TallyGenicom are also known for other important innovations, adding unique features to line matrix technology. The 'Stay Black' or 'Smart Ribbon' is one. TG was a pioneer of cartridge ribbons, which offer longer life and are easier for users to manage then conventional reel ribbons. By adding a unique ink replenishment system based on a paristaltic pump mechanism, TallyGenicom produced the only impact printers to offer consistent print quality. The increasing importance of user productivity resulted in innovations such as 'Auto-Gap' where for the first time the print mechanism would measure paper thickness (as with dot matrix printers) and, rather than the user, set the gap. This maximises print quality for multi-copies and eliminates user error in this area. Improvements in reliability, resulted in the introduction of a shuttle mechanism with no wear parts, with 'Life Time' warranty.
An example of one of these is the IBM 6400 Line Matrix Printer that uses continuous forms.
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