Printers- Output Devices

Printers- Output devices

Out put is data that has been processed into a used form,called information. An output device is any hardware component that can display information to a user. The main and most common output devices in a computer are the Printer and the VDU.
Printer
A Printer is an output device that produces text and graphics on a physical medium such as paper. Printed information is often clled hard copy because the information exists physically and is a more permanent form of output than that presented on a VDU Monitor. Printers can be grouped into impact and non-impact printers.
Impact Printer: An impact printer forms characters and graphics on a piece of paper by striking a mechanism against an ink ribbon that physically contacts the paper.
Non-Impact printer : a Non-impact Printer forms characters and graphics on a piece of paper without actually striking the paper.
The printer speed is usually expressed in pager per minute(ppm). Printer resolution is often expressed in dpi(dots per inch). The larger the number , the higher the resolution.
Advantages of printers include

• Information produced is permanent.

Dis advantages of printers include

• The time to get the printout is slow, when compared with display devices.
• Paper is wasted for obtaining the output.
• Printer are generally noisier than display devices.

Types of Printers in more detail

1. Dot matrix printer
2. daisy wheel printer
3. line printer
4. ink jet printer
5. laser printer
6. plotter

Dot Matrix Printers

A dot matrix printer is an impact printer that produces printed images with a print head striking mechanism. Most dot matrix printers use continuous form paper. A higher number of pins on th print head means more dots are printed, which results in higher print quality

Advantages: Dot matrix printers can print multipart forms and These printers can withstand dusty environment, vibrations and extreme temperature.

Daisy wheel printer

A daisywheel printer is an impact printer that uses a wheel as a print head. As the wheel rotated, a hammer strikes the backside of the spoke and presses it against the paper to print a character.

Advantages: Can print letter quality characters.

Dis advantages: Printing speed is very slow. and Cannot print graphics.

Line printers

A line printer is a high speed impact printer that prints an entire line at a time. The speed of a line printer is measured by the number of lines per minute(lpm). it can print. Line printers are often used with mainframes, minicomputers, or with a network in applications such as manufacturing or shipping.

Ink Jet Printers

These printers are non impact printers that forms characters and graphics by spraying tiny drops of liquid ink onto a piece of paper. Ink jet printers can produce letter quality text and graphics in both black and white and colours. Some ink jet printers can print photo quality images on any type of paper. printer resolution is measured in dots per inch. The speed of an ink jet printer is measured in lines per minute.

Advantages : ink jet printers are generally quiet and These printers can produce high quality colours output.

Disadvantages : Specialized papers are required ot produce high quality colour output. The ink cartridges and specialized papers are expensive. The ink may smear when printed on ordinary paper.

Laser Printers

Laser printers are also known as page printers because thay process and store the entire page before the actually print it. Most laser printers today can print text and graphics in very high quality resolutions, ranging from 600 dpi to 1200 dpi. Laser printers can print text at speeds of four to over thirty pages per minute.

Advantages : Laser printer are generally quiet and fast. Laser printers can produce high quality output on ordinary papers.The cost per page of toner cartridges is lower than other printers.

Disadvantages : The initial cost of laser printer can be high. Laser printers are are more expensive than dot matrix printers and ink jet printers.

Plotter

A Plotter is a large printer that generates high quality documents by moving ink pens over th esurface of a page. plotters are particularly useful to engineers and architects, as the produce high quality blueprints, maps , and floor plans. Pen Plotters and x-y plotters are popular types.

Advantages : Can print of large printers. High quality printing.