Printer

Printer is a kind of peripheral that puts text or a computer-generated image on paper or on another medium.


Types of printers

In terms of printing method, we can divide printers into two basic categories

  • Impact Printer
  • Non-Impact Printer

Impact Printer

Impact printers rely on a forcible impact to transfer ink to the media.

There are three kinds of impact printers

  • Daisy Wheel Printer
  • Dot-Matrix Printer
  • Line Printer


Daisy Wheel Printer

A daisy wheel printer has a removable print wheel consisting of spokes. Each spoke ends with a raised character. The wheel turns to align the desired letter with the next printing position, and a hammer strikes the spoke end.

Daisy wheel printers produce clear and precise output of text, which is why they are often called letter quality printer


Dot Matrix Printer

A dot matrix printer is a printer that produces characters made up of dots using a wire-pin print head.

The common desktop dot matrix printer, also known as a serial dot matrix printer, uses one or two columns of dot hammers that are moved across the paper. The more dot hammers used, the higher the resolution of the printed image. For example, nine pins produce draft quality, and 24-pin heads produce typewriter quality output. Speeds range from 200 to 400 cps.


Line Printer

The line printer is a form of high speed impact printer which prints a whole line of characters at once.

They are often used with mainframes, minicomputers or networked machines.


Non Impact Printers

Non-impact printers form characters and images without making direct physical contact between printing mechanism and paper.

Two types of non impact printers are often used with microcomputers

  • Inkjet printer
  • Laser printer



Inkjet Printer

An inkjet printer forms an image by using electromagnetic fields to guide electrically charged droplets of ink onto the page.

Inkjet printers can exceed the speed of dot matrix printers and produce high quality image like laser printers.

There are two ways to "jet" the ink in drop on demand systems. The thermal method heats a resistor and expands an air bubble. This method is commonly referred as “Bubble Jet”. This technology is used by Canon and HP inkjet printers.

Piezoelectric technology uses piezo crystals. A crystal is located at the back of the ink reservoir of each nozzle. The crystal receives a tiny electric charge that causes it to vibrate. When the crystal vibrates inward, it forces a tiny amount of ink out of the nozzle. This technology is used by Epson inkjet printers


Laser printer

Laser Printer is an electrophotographic printer that is based on the technology used by photocopiers. Laser printers produces very sharp images of text and graphics.

A focused laser beam and a rotating mirror are used to draw an image of the desired page on a photosensitive drum. This image is converted on the drum into an electrostatic charge, which attracts and holds toner. A piece of electrostatically charged paper is rolled against the drum, which pulls the toner away from the drum and onto the paper. Heat is then applied to fuse the toner to the paper. Finally, the electrical charge is removed from the drum and the excess toner is collected. By omitting this final step and repeating only the toner-application and paper-handling steps, the printer can make multiple copies.

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