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Unformatted text preview: e than one pen in
the pen(s) holding mechanism. Since each pen is program selectable, pens having ink of
different colors can be mounted in different holders to produce multi colored designs.
The plot size is restricted by the area of the bed. Some may be as small as. A4 size (8"xll"
page) while some very large beds used in the design of cars, ships, aircrafts, buildings,
highways, etc. can be up to 20 ft. by 50 ft. Some plotters are also designed to etch plastic
or metal plates. In this case, the plastic or metal sheet is spread on the bed and the
drawing pen has a sharp-edged needle. A flatbed plotter is shown in Figure 9.35.
Plotters are normally very slow in motion because of excessive mechanical movement
required during plotting. Hence there is a great mismatch between the speed of the CPU
and the speed of a plotter. Because of this reason, in most cases, output is first transferred
by the CPU onto a tape and then the plotter is activated to plot the design from the
information on the tape. However, in case of a computer system dedicated to design
work, the CPU may send output directly to a plotter.
Computer Output Microfilm (COM)
COM is an output device that allows computer output to be recorded on a sheet or roll of
microfilm as microscopic filmed images. COM devices commonly use a sheet of film
measuring 4"x6" for recording output information. This sheet of film is called a
microfiche ("fiche" is pronounced as "fish". It is a French word that means card). COM
recording process produces page images that are 48 or more times smaller than those
produced by conventional printers. Hence a single microfiche can hold about 300 times
as much information as a standard computer printed page.
COM uses a microfilm recorder for recording output information on a microfiche, and a
microfilm reader to view the information recorded on a microfiche. The microfilm
recorder receives output information from the computer system which it projects pageby-pa...
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This document was uploaded on 04/07/2014.
- Spring '14