【NTT】 High-Speed Line Printer (LP1500)

To further improve the speed and the price/performance ratio, in 1975, the Electrical Communication Laboratories (ECL) of Nippon Telegraph and Telephone Public Corporation (now NTT) began studies on the printing-hammer and paper-handling mechanisms, which were the keys to increasing printing speed. In 1976, they conducted partial prototyping of a printing machine with a speed of 1,500 lines/min; the unit was completed in 1977.

NTT examined the printing-hammer mechanism—specifically, ways to make it lighter and to drive it—to prevent deterioration in printing quality due to the increased speed. With regard to the former, NTT conducted stress analysis of the printing-hammer form, used a titanium alloy with extremely low density and superior specific strength, conducted research on methods of machining that alloy, and thereby achieved a highly reliable lightweight hammer half the weight of previous printing hammers. With regard to the latter, NTT developed a mechanism with improved heat radiation characteristics and stable operation time by using a high-efficiency drive magnet and high-speed drive.

For the paper-handling mechanism, NTT developed a folding mechanism that was stable even at high speeds. This was done by using a sine wave drive servo-motor that took into account the vibration characteristics during bending of the paper.

At the time, this printer had the highest printing speed in the world, and it was used in various systems as a key peripheral for DIPS.

High-Speed Printer Capable of Printing at 1500line/min—the Highest Printing Speed in the World