Dot-Matrix Printers

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 arrangedto 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 typewriter 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.
Papermoves 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 themto create multipart 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.
Advantages:
1.They can print on multi-part stationary or make carbon copies
2. Low printing cost
3. They can bear envoiromental conditions.
4. Longlife

Disadvantage
1. Noise
2. Low resolution
3. Very limiter Color performance
4. Low speed