Daisy wheel printing

It uses interchangeable pre-formed type elements, each with typically 96 glyphs, to generate high-quality output comparable to premium typewriters such as the IBM Selectric, but two to three times faster.

The personal and office printing industry would soon adapt again to the advent of the PC and word processing software.

In 1889 Arthur Irving Jacobs patented a daisy wheel design that was used on the Victor index typewriter.

In 1970 a team at Diablo Systems led by engineer Dr Andrew Gabor developed the first commercially successful daisy wheel printer, a device that was faster and more flexible than IBM's Selectric devices, being capable of 30 cps (characters per second), whereas the Selectric operated at 13.4 cps.

From 1981 onwards the IBM PC's introduction of "Code page 437" with 254 printable glyphs (including 40 shapes specifically for drawing forms), and development of Xerox Star-influenced environments such as the Macintosh, GEM and Windows made bit-mapped approaches more desirable, driving cost reductions for laser printing and higher resolution for impact dot matrix printing.

The Xerox typewriter was well received but never achieved the projected sales numbers due to the advent of the PC and word processing software.

The typewriter was later modified to be compatible with PCs but the engineering which made it a low cost device reduced its flexibility.

In use a servo motor rotates the daisy wheel to position the required character between the hammer and the ribbon.

The daisy wheel and hammer are mounted on a sliding carriage similar to that used by dot matrix printers.

Most daisy wheel printers supported a relatively coarse and extremely slow graphics mode by printing the image entirely out of dots (formed by the "period" character).

This would have the advantage that vertical dot combinations could be printed in a single impact, without requiring fine rotation control of the platen roller.