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e\L-lovely-eng\comm5-1.pmd IInd 16-9-11 IIIrd 27-12-11 IVth 4-1-12

Information and Communication Technology Applications

Laser printers are very popular and have become an essential part of Desk Top Publishing (DTP).
Notes Although laser printers are costlier than dot matrix, they are generally preferred in all offices due to
their best quality of printing. There are many models of laser printers depending upon the speed
and number of dots printed. The latest model of laser printer is 1200 DPI (Dots Per Inch), which can
print 10 pages/minute. Some high speed laser printers give a speed of upto 100 pages/minute.
(b) Inkjet Printers. These printers print the characters by spraying the paper with electrically charged
ink. These printers give better quality than character printers but not better than laser printers.
They are cheaper than laser printers, hence, used widely in many offices. They also offer an option
of using colour cartridges for multi-color printing. A picture of an inkjet printer is shown in
Figure 5.22.

Figure 5.22: An inkjet Printer

(c) Thermal Printers. These printers print the characters by melting a wax-based ink off a ribbon onto
a special heat sensitive paper. They give Letter quality printing but are relatively expensive in
maintenance than other printers.

Speakers/Headphone
Speakers is another basic output device of Today’s computer, which is used to produce sound and
music. There are many models of stereo speakers with different size and volume capacities (350 W,
etc.).
Headphone is also a basic output device of a computer, which is used mainly on Internet to listen
sound and music. It generally comes as a set with a microphone.

5.1.4 Special Output Devices

The output devices, which are not essential to get the output on a computer, are called Special
Output Devices. These devices are not required for basic output operations, but are used for special
purposes. These devices include Plotter and Computer Output Microfilm (COM). Let us discuss
about them.

Plotter
Plotter is an important output device, used to print high quality graphics and drawings. Although
the graphics can be printed on printers, the resolution of such printing is limited on printers. Plotters
are generally used for printing/drawing graphical images such as charts, drawings, maps, etc. of
engineering and scientific applications. Some important types of plotters are shown in Figure 5.23
and are discussed below:

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