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Output Device


Printers


Printer is an output device of the computer. 

It is used to produce the hard copy output in business application. Hard copy means to print data and information on the paper from the computer. 

 

Printers give text information as well as graphical information. 

 

The quality of a printer is determined by its resolution. 

 

Resolution describes the sharpness and clarity of an image. If the resolution is high so the image will be better. 

The resolutions are measured in dots per inch (dpi). For the better quality of an image, more dpi is given. The dots are so small and together that they project the image as a solid one. For the example, if the printer has a resolution of 600 dpi, it means that printer is capable of printing 36,000 dots per square inch.

 

Classification of Printer

The printers can be broadly classified as shown in the image below:

 

Impact Printer 

Impact printer strikes a head or a needle against an ink ribbon to make a mark on the paper. 

Impact printer may be three types: (a) Daisy Wheel Printer, (b) Drum Printer, and (c) Dot Matrix Printer.

 

  • ​Daisy Wheel Printers

It is used to print one character at a time. 

The head of this printer resembles daisy flower, with the printing arms that appear like the petals of a flower and thus its named as daisy printer. 

It can be used to print professional letter quality documents. It also known letter quality printer as the print quality is better as a high-quality typewriter. It gives high resolution output. 

Its reliability is higher than that of dot matrix printer. It can have speed upto 90 cps. 

The time required to rotating the print wheel for each character desired, that’s a reason it is slow in use. So these printers are slower and expensive than dot matrix printers.

  • Drum Printers

It is print a single line at a time. 

Its printing speed varies from 150 lines to 2500 lines in a minute with 96 to 106 characters on a 15 inch line. 

Line printers are designed for heavy printing applications. These printers are faster than character type printers. 

These type of printers produce lot of noise.

 

  • Dot Matrix Printers 

Dot Matrix printing technology is very old. It can print one character at a time. It can print any shapes of character, special characters, graphs and charts which user wishes to print.

This printer’s speed can be measured by Character per second (cps). The speed can vary from about 200 to 500 cps.

The print quality is determined by the number of pins, which can be varying from 9 to 24. For the higher print resolution, more pins per inch are given.

 

Non-Impact Printer

Non-impact printers does not use striking device to produce characters on the paper. This type of printers spray ink on papers through nozzles to form characters and patterns.

Non-Impact printer may be of two types: (a) Daisy Wheel Printer, (b) Drum Printer

 

  • Inkjet Printers

These printers are generally used for home purposes. It is a printer that place extremely small droplets of ink onto paper to create an image.

Its cost is relatively higher than dot matrix printers but the quality is better.

These kind of printers produce high quality prints and graphics due to its high resolution feature.

 

  • Laser Printers

Laser produces high qualiy text and images for personal computers.

Laser printer are also known as page printer. Reason being they process and store the entire page before printing it.

They donot produce noise and print faster. Thus they are also preffered to print large amount of contents on large volume of papers. 



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