Computer Output Device: Printers

1. Computer Output Device: Printers www.assignmentpoint.com

2. Printers A computer printer, or more commonly a printer, produces a hard copy (permanent human-readable text and/or graphics) of documents stored in electronic form, usually on physical print media such as paper or transparencies. www.assignmentpoint.com Click here to Types of printers

3. Many printers are primarily used as local computer peripherals, and are attached by a printer cable to a computer which serves as a document source. Some printers, commonly known as network printers, have built-in network interfaces (typically wireless or Ethernet), and can serve as a hardcopy device for any user on the network. Individual printers are often designed to support both local and network connected users at the same time. www.assignmentpoint.com

4. Type of printers • Laser printer • Inkjet printers • Dot-matrix printer www.assignmentpoint.com

5. Laser printer Disadvantages: Non-color laser printers are more expensive than ink-jet printers (but the difference is narrowing). Color laser printers are considerably more expensive. (but their speed and high quality output means they are becoming more popular). Advantages: They are quiet and fast and produce high quality printouts. Running cost are low because although toner cartridges are expensive to replace, they last a long time. Disadvantages: Non-color laser printers are more expensive than ink-jet printers (but the difference is narrowing). Color laser printers are considerably more expensive. (but their speed and high quality output means they are becoming more popular). Advantages: They are quiet and fast and produce high quality printouts. Running cost are low because although toner cartridges are expensive to replace, they last a long time. A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. Like photocopiers, laser printers employ a xerographic printing process but differ from analog photocopiers in that the image is produced by the direct scanning of a laser beam across the printer's photoreceptor A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. Like photocopiers, laser printers employ a xerographic printing process but differ from analog photocopiers in that the image is produced by the direct scanning of a laser beam across the printer's photoreceptor www.assignmentpoint.com

6. Inkjet printers How it works: The print head contains tiny nozzles through which different coloured inks can be sprayed onto the paper to form the characters or the graphic images. The ink is forced out by heat or by tiny piezoelectric crystals which change shape when an electric current is applied across them. Disadvantages: The ink cartridges can be expensive so running costs can be high. The printing speed is slow compared to a laser printer.  Advantages: These printers are relatively inexpensive and produce high quality black and white or colour printing.  www.assignmentpoint.com

7. Dot-matrix printer Disadvantages: The printing quality is low - these printers produce low to medium quality black and white printing and can only print low resolution graphics. Because of the impact of the pins against the paper, these printers can be quite noisy. Advantages: The purchase cost is low and the running costs are very low. They can print fairly quickly, particularly if you remember that multiple copies are being printed in one print run. They are robust and can operate in harsh environments. If several sheets of self-carbonating paper are placed into the printer then the impact will produce multiple copies. How it works:  This has a print head that travels across the paper. The head has a set of pins which are pushed out to form the shape of each character The pins hit an ink ribbon against the paper as the print head moves along. An animation showing how head of a 21 pin dot-matrix printer moves across the paper, firing the pins that strike the ink against the paper. www.assignmentpoint.com