The IBM Selectric typewriter (occasionally known as the IBM Golfball typewriter) is the electric typewriter design that brought the typewriter into the electronic age.

Selectric I

Selectric II
Instead of typebars it had a pivoting typeball that could be changed to use different fonts in the same document.

The ability to change fonts, combined with the neat regular appearance of the typed page, was revolutionary and marked the beginning of desktop publishing. Later models with selective pitch and built-in correcting tape carried the trend even further. Any typist could produce a polished manuscript.

Due to their speed (14.8 characters/sec), immunity to clashing typebars, and reliability, Selectric models were also widely used as terminals for computers, replacing Teletypes.

The machine had a key lockout feature that smoothed out the irregular fingerstrokes of the typist. When a key was pressed a narrow metal tab was pushed into a slotted tube full of ball-bearings under the keyboard. These balls were adjusted to have enough horizontal space for only one tab to enter at a time. The typist could press multiple keys at the same time and was guaranteed that they would cycle the machine in the order they were pressed (and held down). This gave some users the impression that there was a storage buffer.

The Selectric typewriter was first released in 1961 and is generally considered to be a design classic. After the Selectric II was introduced a few years later, the original design was designated the Selectric I. The Correcting Selectric II differed from the Selectric I in many respects:

  • The Selectric II was squarer at the corners, whereas the Selectric I was rounder.
  • The Selectric II could be switched (with a lever at the top left of the "carriage") between 10 and 12 characters per inch, whereas the Selectric I had one fixed "pitch".
  • The Selectric II had a lever (at the top left of the "carriage") that allowed characters to be shifted up to a half space to the left (for inserting a word one character longer or shorter in place of a deleted mistake), whereas the Selectric I did not.
  • The Selectric II had auto-correction (with the extra key at the bottom right of the keyboard), whereas the Selectric I did not. (The white correction tape was at the left of the typeball and its orange take-up spool at the right of the typeball.)
  • The Selectric II had a lever (above the right platen knob) that would allow the platen to be turned freely but return to the same vertical line (for inserting such symbols as subscripts and superscripts), whereas the Selectric I did not.
Both Selectric I and Selectric II were available in standard and wide-carriage models and in various colors, including red and blue as well as traditional neutral colors, and both used the same typeballs, which were available in many fonts, including symbols for science and mathematics, OCR faces for scanning by computers, script, Old English, and more than a dozen ordinary alphabets. The typeballs came in two styles: One had a flip-up black plastic lever that could break off, and the other had a metal spring clip with two wire wings that squeezed together and did not break. Over the years, there were several different cartridge styles for the ribbons, even in the same model Selectric, and they were not interchangeable.

In the 1980s IBM introduced a Selectric III and several other Selectric models, some of them word processors or type-setters instead of really typewriters, but by then the rest of the industry had caught up with the trend, and IBM's new models did not dominate the market the way the first Selectric had.

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