00, making it competitive with top-of-the-line dot matrix printers that are as fast. The
laser printer will corner more of the market because it is quiet, prints on envelopes, and
doesn't need the perforated, folded paper used by many dot matrix printers.
Table 2-1. Comparative speeds of most common printers.
(2) Ink jet printers. Ink jet printers form the image by shooting a stream of
charged ink toward the paper. The ink passes through an electrical field that arranges
the charged particles into characters. Costs generally run from 0 to 00, with a
decent model obtainable for under
,000. Ink jet output looks almost as good as laser
output and works on sheet-fed paper. But ink jet printers are slow, printing out 200
characters per minute. Still, they are small, quiet, relatively cheap, and probably the
best bet if you need to give correspondence a crisp, professional look, but do not need
a graphics capability.
f. Special Purpose Output. These devices provide output in forms that
traditional printers cannot produce.
(1) The video display terminal (VDT) or monitor provides nonpermanent
visual display of output, known as soft copy. Most screens hold up to 24 lines, each
containing DO characters.
soft copy: nonpermanent visual record.
(a) Types of VDTs. There are actually three different types of VDTs.
The cathode-ray tube (CRT) operates on the same principle as the television. Using
very high voltage, a cathode-ray tube throws a beam of energy on a phosphor-coated
screen, causing an image to appear. Most VDTs are of the CRT variety. Another type
of VDT uses a Liquid Crystal Display (LCD) like that of a digital watch. And the newest
type of VDT uses plasma technology.