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Output Devices
Introduction
“An output device is any hardware used to communicate processed data to the user, e.g. Monitor, speakers and printers.”
Printers
One of the most One of the most popular output popular output devicesdevices
Inkjet printers Laser printers Graph plotters Dot matrix printers Thermal printers Braille printers
Inkjet printers
Popular for domestic use Small jets of ink sprayed on to paper Three systems used for printing
– Nozzles controlled by crystals which change shape– Ink heated and pushed through nozzles (bubblejet)– Continuous flow – ink squirts continuously from
nozzles
Laser Printers
The most versatile – but are more expensive Pages are set up in full before printing They have four main parts:
– Rotating drum – has an electrical charge– Laser – etches a negative electrically charged
image onto the drum– Toner cartridge – drum attracts ink from toner
cartridge to areas that are charged– Fuser unit – heats the paper, to make ink stick
What do you want from your printer?
Speed– Lasers fast – but modern inkjets can be just as fast
Resolution– Lasers offer best quality with highest dpi – but modern inkjets
also offer very good quality Initial Cost
– Cost of colour lasers has reduced significantly – but inkets are still cheaper
Running Costs– Lasers are cheaper if you print out a lot of pages
Graph plotters
Often used with CAD An arm moves over the paper, spraying ink Designed to handle large sheets of paper Output – high quality vector graphics
– Good for architectural drawings
Dot matrix printers
Used a lot in the past – receipts
Print a series of dots that form characters
Useful if carbon copies are needed as they are impact printers
Thermal printers
Often used in calculators and fax machines
Marks transferred to paper, using heat
Braille printers
Also known as embossers Create sequences of raised
dots on the paper
Braille sensing
Monitors
Also known as VDUs (Visual Display Units)
Two main types : – CRT (Cathode Ray Tube)– Flatscreen – LCD – TFT -
Plasma
LCD Projectors
This presentation is being output by a LCD projector.
Also known as beamers
Speakers
Add another dimension
Integral part of any multimedia system
Can be used as primary output – speech output for the visually impaired
Finally.....remember....
G.I.G.O.– Garbage– In– Garbage– Out
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