Printers are the most commonly used output device. They are used to print output on the paper. The output may be in the form of characters, symbols and graphics information printed on paper is called hardcopy
Categories/Types of Printers
Printers are classified into two main categories or types:
1- Impact Printers
2- Non-Impact Printers
Non-Impact Printers
The printers that produce output on paper without striking the paper are known as non-impact printers. They Use Electrostatic , inkjet, and thermal technologies for printing.
Non-Impact printers are faster and produce hight quality output than impact printers. They can print up to 24 pages per minute. They produce no noise during printing. These printers are costly than impact printers
The Examples of Non-Impact printers are :
1- Laser Printer
2- Inkjet Printer
3- Thermal Printer
Laser Printer
Laser stands for Light Amplification by Simulated Emission of Radiation. A laser printer is the fastest and hight quality non-impact printer. It works like a photocopier. The laser printer transfers the image of output on paper using LASER technology and toner. Toner is an ink powder. It is used in laser printers and photocopiers also
The laser printer has a special drum inside it. first the image of output is created on the drum, and then it is transferred from drum to paper. The image of output is created on the drum by throwing magnetic ink powder in the form of microscopic dots. These dots can be from 300 dpi to 1200 dpi (dpi means dots per inch and these dots refers to microscopic dots).
The Laser printer can print both text and graphics in very high quality resolution. Laser printer prints one page at a time. The laser printers are, therefore also called page printers. The printing speed of laser printer is about 4 to 32 pages per minute for microcomputer and up to 200 pages per minute for mainframe computers.
Ink Jet Printer
Ink-jet printer is type of non-impact printer. It creates output on paper by spraying tiny drops of liquid ink. Inkjet printer has print-head that can spray very fine drops of ink. It consists of print cartridge filled with liquid ink and has small nozzles in form of matrix. Like dot matrix printer, the combination of nozzles is activated to form the shaper of character or image on the paper by spraying the liquid ink. These printers have resolution ranging from 300 to 720 dpi.
The ink-jet printers have low price than laser printers. They are also slower and have low print quality than laser printer. However, They are faster and have hight print quality than dot matrix printers. The printing speed of ink-jet printer is from 1 to 6 pages per minute.
Thermal Printer
Thermal printer is another type of non-impact printer. It can only print output on a special heat sensitive waxy paper. The image if the output is created on the waxy paper by burning dots on it. For coloured output, coloured waxy sheets are used.
Thermal Printer produces a high quality printout. It is quite expansive as compared to other non-impact printers.
