Ans : Printers :
A printer is a device that accepts text and graphic output from a computer and transfers the information to paper. In terms of technology utilized the printers are divided into two main categories.
(a) Impact Printers :
They print by striking the ink ribbon against the paper.
They produce much noise and are also called noisy printers.
They can produce text prints but cannot print high quality graphics.
Examples of impact printers are Daisy Wheel , Dot Matrix and Line Printers.
1. Daisy Wheel Printer :
It has a metal wheel on which the shapes of characters are embossed. A hammer presses the wheel against the ink ribbon to print on paper.
2. Dot - Matrix Printer :
Dot Matrix printers creates characters by striking pins against an ink ribbon. Each pin makes a dot and combinations of dots form characters and illustrations.
3. Line Printer :
Line printers contains a chain of characters on an entire line. Line printers are very fast but produce low quality print. Drum and Chain printers are sub classes of Line Printers.
(b) Non - Impact Printers :
They print without striking paper with hammer instead they use technology like magnetic , electronic , thermal , chemical , optical , inkjet or laser to give output on paper.
They do not produce much noise and are also called noiseless printers.
They can produce high quality text and graphics output.
Examples of non - impact printers are Laser printer , inkjet printer , Thermal printer , LCD & LED printer.
1. Ink Jet Printer :
Ink Jet printers sprays inks on sheet of paper. They produce high quality text and graphics.
2. Laser Printer :
Laser printer works like a photocopier machine and produce high quality text and graphics.
3. LCD & LED Printer :
These printers uses either liquid crystal display or light emitting diodes to produce an image on the drum.
4. Thermal Printer :
Thermal printer works by pushing heated pins against heat sensitive paper.