Printer classification

Printer classification based on their technology. Typical printer types are:
1. Dot matrix printer
2. Ink-jet printer
3. Laser printer
4. Thermal printer
Dot Matrix Printer
A dot matrix printer or impact matrix printer refers to a type of computer printer with a print head that runs back and forth on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like a typewriter.
Dot-matrix technology uses a series or matrix of pins to create printed dots arranged to form characters on a piece of paper. The speed at which a dot-matrix printer prints is measured in the number of characters it can produce per second. Unlike a type-writer or daisy wheel printer, letters are drawn out of a dot matrix, and thus, varied fonts and arbitrary graphics can be produced. Because the printing involves mechanical pressure, these printers can create carbon copies and carbonless copies.
The print head mechanism pushes each pin into the ribbon, which then
strikes the paper. The original dot-matrix print heads had 7 pins, while newer,
letter-quality print heads use 24 pins to produce near letter quality (NLQ) documents. Each pin is driven forward by the power of a tiny electromagnet or solenoid, either directly or through small levers (pawls).
Dot-matrix printers are called impact printers because the printing mechanism physically strikes the page. The continual motion of the pins through the print head creates a ton of heat, so avoid touching the print head after printing a handful of pages or more. A hot print head can give you a nasty burn.
Paper moves through a dot-matrix printer using a tractor-feed mechanism. Spoked wheels located on each side of the paper feed mechanism move the paper. The spokes on the outer edges of the wheels fit into holes on the sides of specially designed continuous form paper. As the wheels turn, they pull the paper through the printer.
Because impact printers physically strike the page, you can use them to create multi part forms with ease.Many offices and government agencies use them for that very reason. Although impact printers have been replaced in most homes and offices by newer, sexier inkjet and laser printers , they still retain a substantial portion of the market in their niches.
1.They can print on multi-part stationary or make carbon copies
2. Low printing cost
3. They can bear environmental conditions.
4. Long life

1. Noise
2. Low resolution
3. Very limiter Color performance
4. Low speed  
Thermal Printers:
Thermal printers use a thermal ribbon which is soaked with a wax type ink which is melted and then transferred to the paper.
In some thermal printers a thermo sensitive paper is necessary. In this case the paper passes over a thermal head and the carbon coating turns black in the heated areas. Thermal printers have low noise, low cast while they are also compact. They are also known for their low printing speed and high running cast.
Ink Jet Printers
Ink jet printers spray a very small amount of ink onto the media. This is done by using a piezoelectric element. When voltage are applied to the element, in bends and creates a pressure wave to force out a drop of ink. Ink jet printers have low cast, compact size, low noise. Their color printing quality is affordable. Some ink jet printers may require special paper. Usually speed of ink jet printers is slower than laser printers.
Laser Printers:
Laser printing is the most advance technology. In Laser printing, a computer sends data to the printer. Printer translates this data into printable image data. This kind of printers uses xerographic principle. A laser beam discharges photo sensitive drum. A Latent Image is created on drum, during development process toner is attracted to the drum surface and then transferred to the paper.
Laser printing quality is high. These printers have low noise, high speed while they are more expensive than ink jet or dot matrix printer and they are generally large in size.

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