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 popular output devices One of the most popular output devices 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