Output Devices 3

Printer Memory

It is important to realize that most printers have their own memory chips, in the same way that each computer has its own memory. If you are printing very large graphics (i.e. pictures), and want the best quality output from your printer then you should consider adding more memory to your printer. This must only be done by a qualified person, and has the benefit of really speeding up the rate at which you can print pages inmany cases.


Cost of printer peripherals

When you buy a printer, one of the things the salesperson will not necessarily
stress is how much it will cost to keep that printer running. Laser printers do
not use ink; they use something called toner that is normally supplied in a
sealed unit called a toner cartridge. Each toner cartridge will allow you to
print a certain amount of pages and when the toner is used up it needs to be
replaced. In some cases the costs of these toner cartridges is very high.

Plotters

A plotter is an output device similar to a printer, but normally allows you to
print larger images. Their use is common in the design and research sector.

Speakers

Most computers are sold with the capability to add a pair of speakers to your
system unit. In fact, in some cases, the monitor may have speakers built
directly into the unit. This enhances the value of educational and presentation products and can now be considered a standard PC component.

Speech synthesizers

A recent development is the ability not only to display text on a monitor but
also to read the text to you. Thus, you could receive a text email from a
colleague and the system could read that email to you. This is of enormous
benefit to the visually impaired when using a computer. On the flip side, it is
now possible to use a microphone to talk to the computer and for the computer to directly convert the spoken word into text that will be displayed within say your word-processor. While these systems are far from foolproof they are getting better as more advanced software is being made available.

Output Devices 2

Different types of printer

There are many different types of printers. In large organizations, laser
printers are most commonly used because they can print very fast and give a very
high quality output. In most organizations, the printers are connected to the
computers via a network. This means that each person with a computer does not
require his or her own printer. Each computer connected to the network can print
using a particular shared printer.

Laser printers

Laser printers produce high print quality at high speed. They are called "laser printers" due to the fact that they contain a small laser within them. There is a wide range of laser printer manufacturers and one buzzword to be aware of is Postscript, a type of printer that is designed to give very high quality reproduction of pictures.

Color laser printers

Originally, most laser printers would only print in black and white (mono). More recently color laser printers have dropped in price and are entering wide spread use. While many of these produce excellent results, you should be aware of the fact that the "price per page", especially if you are using a lot of color on a page can be very high compared to the cost of printing in black and white.

Inkjet printers

Inkjet printers work by using tiny jets to spray ink onto the paper. Inkjet printers are very quiet in operation and produce print quality comparable to that of laser printers, though laser printers still have the edge in terms of speed. Inkjet printers are ideal for low volume printing where high quality print is required and speed is not a high priority, e.g. printing letters in a small office or in the home.

Dot Matrix printers

Dot matrix printers work by firing a row of pins through an ink ribbon onto the paper. The more pins the print head has the higher the quality of the print, most modern dot matrix printers have 24 pins. Unfortunately, dot matrix printers can generate a lot of noise and do not produce a very high quality of print, especially when printing graphics. As a result, the inkjet printer has now largely replaced the dot matrix printer. Dot matrix printers are used for high volume / low quality printing, e.g. printing company pay slips

Output Devices 1

Identify common outputdevices for displaying the results of processing carried out by a computer, suchas: monitors, screens, printers, plotters, speakers. Know where these devicesare used.

The VDU (computer monitor or screen)

The VDU (Visual Display Unit) is the computer
screen used for outputting information in an understandable format for humans.
Remember that at the end of the day the computer works in binary code (a series
of on/off impulses). It is hard to realize that the original electronic
computers did not have a screen

Flat screen monitors

Traditional computer monitors are based on the same sort of technology that is
used within a television screen.

More recently, flat screen computer monitors have become available. These take
up a lot less room on a desk and use less energy than the traditional, more
bulky monitors.

Screen size

You should be aware that often if you specify a screen of a certain size, say a
17-inch screen, that this is the size measured diagonally, not horizontally
across the screen. If you are upgrading you should also ask for the "visible
viewing area" of the screen.

Graphics for games

Many games require very advanced graphics cards (boards) to be installed within
your computer to make them run. These advanced graphics cards contain their own
CPU that is dedicated purely to displaying the graphics on your screen. You
should find that a recent PC has this advanced graphics capability built-in
where as PCs from only 2-3 years ago may not.

Computer presentation projection devices

These are projection devices that can be attached to your computer and are
useful for displaying presentations to a group of people. They are best used in
combination with presentation programs, such as Microsoft PowerPoint. They are
used within education and are also very popular for sales presentations. The
price of these devices has dropped dramatically recently. When purchasing one of
these devices the two things to look out for are the resolution
(go for a minimum of XGA) and the brightness of the lamp (the brighter the
better). Other factors to be aware of is the quietness (or otherwise of the
device) and well as the cost of replacement bulbs.