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How the IBM 1403 Printer Hammered Out 1,100 Lines Per Minute

schwit1 quotes a report from IEEE Spectrum: The IBM 1460, which went on sale in 1963, was an upgrade of the 1401 [which was one of the first transistorized computers ever sold commercially]. Twice as fast, with a 6-microsecond cycle time, it came with a high-speed 1403 Model 3 line printer. The 1403 printer was incredibly fast. It had five identical sets of 48 embossed metal characters like the kind you’d find on a typewriter, all connected together on a horizontal chain loop that revolved at 5.2 meters per second behind the face of a continuous ream of paper. Between the paper and the character chain was a strip of ink tape, again just like a typewriter’s. But rather than pressing the character to the paper through the ink tape, the 1403 did it backward, pressing the paper against the high-speed character chain through the ink tape with the aid of tiny hammers. Over the years, IBM came out with eight models of the 1403. Some versions had 132 hammers, one for each printable column, and each was individually actuated with an electromagnet. When a character on the character chain aligned with a column that was supposed to contain that character, the electromagnetic hammer for that column would actuate, pounding the paper through the ink tape and into the character in 11 microseconds. With all 132 hammers actuating and the chain blasting along, the 1403 was stupendously noisy […] The Model 3, which replaced the character chain with slugs sliding in a track driven by gears, took just 55 milliseconds to print a single line. When printing a subset of characters, its speed rose from 1,100 lines per minute to 1,400 lines per minute.

Read more of this story at Slashdot.

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