NEC Spinwriter

What the NEC Spinwriter was

The NEC Spinwriter was a line of letter-quality printers produced by NEC (Nippon Electric Company, today NEC Corporation) beginning in 1977. Its manuals describe it as "a micro-processor controlled serial impact printer which prints fully formed characters bi-directionally under user control," designed for applications "in which impeccable print quality and multiple copy capability are required." Because each glyph was a solid, molded character struck through an inked ribbon rather than built from dots, output looked like it came from a good electric typewriter, which made the Spinwriter a mainstay for business correspondence, forms, and reports during the era before laser printing became affordable. The name spanned many models over the years, including the 3500, 5500, and 7700 series.

The thimble print element

The Spinwriter is best known for its distinctive print element. Rather than the flat, spoked "daisy wheel" used by competing letter-quality printers, NEC bent the petals into a cup shape, producing what it called a print thimble. According to NEC's service documentation, the thimble "has 64 fingers. Two characters are arranged vertically on each finger, allowing for a total of 128 characters on a print thimble." To print, the thimble is rotated bi-directionally and shifted vertically to bring the selected character into position, then "the print hammer is actuated to impinge the print thimble character against the ribbon and onto the paper wrapped around the platen." A few fingers near the home position are shortened so the operator can see the last characters printed.

Print method and performance

The Spinwriter was a serial (character-at-a-time) impact printer that printed bi-directionally to save time on the return sweep. NEC/Prime service specifications for the Model 5510/5515 rate the machine at up to 55 characters per second at 12 characters per inch. The same specifications list selectable serial data rates from 110 to 1200 baud; some third-party listings quote the lower baud figures (for example 15 to 20 cps) as if they were the engine speed, but those numbers reflect the communication rate rather than the printer's mechanical throughput. Character pitch could be set to 10 or 12 characters per inch, giving a print line of 136 columns at 10 cpi or 163 columns at 12 cpi across paper up to 16 inches wide. Inking used a replaceable ribbon cartridge, offered as single-color and two-color nylon loops or a sharper multi-strike film ribbon.

Interchangeable thimbles, fonts, and languages

As with the interchangeable type element of the IBM Selectric typewriter, the Spinwriter's thimble could be lifted out and replaced to change the printed typeface. NEC and third-party suppliers offered a wide catalog of thimbles covering common office typefaces at 10 and 12 pitch, along with elements for other alphabets and character sets. This made a single Spinwriter adaptable to different document styles and to multilingual work without any change to the printer itself, one reason the machines saw broad use in offices and institutions.

Significance and place in printing history

The Spinwriter sat squarely in the letter-quality impact category that dominated formal document printing in the late 1970s and early 1980s, alongside daisy-wheel machines from other makers. Its thimble was a notable engineering variation on the daisy-wheel idea, and the design is preserved as a representative artifact by institutions including the Computer History Museum, the System Source Computer Museum, and the Smithsonian's National Museum of American History. Where dot-matrix printers such as the Epson FX-80 traded ultimate print quality for speed and graphics flexibility, the Spinwriter prioritized crisp, typewriter-grade characters and clean multi-part copies.

Decline and legacy

Letter-quality impact printers like the Spinwriter were gradually displaced as laser printers, beginning with machines such as the original HP LaserJet and the Apple LaserWriter, brought comparable or better print quality with far higher speed, quieter operation, and full-page graphics and font flexibility. NEC continued to support Spinwriter consumables and documentation well after the machines left active production, and surviving units and thimbles remain sought after by collectors and museums as examples of the fully-formed-character printing era.