A computer peripheral that puts text or a computer generated image on paper or on another medium, such as a transparency. Printer can be categorized in several ways the most common distinction is IMPACT and NON-IMPACT.
Is the method used by the conventional type writers? In some type of impact printing a metal “hammer” embossed with a character strikes a print ribbon, which presses the characters image into paper. In other types the hammer strikes the paper and presses it into the ribbon characters created through impact printing can be formed by either a solid font or dot matrix printing mechanism.
NON – IMPACT PRINTING:
Does not depend on the impact of metal on paper? In fact no physical contact at all occurs between the printing mechanism and the paper. The most popular non-impact methods today utilize thermal transfer, ink-jet.
TYPES OF PRINTERS
· DOT MATRIX PRINTER:
Any printer that produces character made up of dots using a wire pin printed head. The quality of output from a dot matrix printer depends largely on the number of dots in the matrix, which might be low enough to show individual dots or might be high enough to approach the look of fully formed characters. Dot matrix printers are often categorized by the number of pins in the printer head typically, 9 or 24.
· LINE PRINTERS:
Any printer that prints one line at one time, as opposed to one character at a time or one page at a time. Line printers typically produce the 11 by 17 inch “computer” printout. They are high speed devices and are often used with mainframes, minicomputers, or networked machines rather than with single user system. Types of line printers include chain printers and band printer.
· LASER PRINTERS:
An electro photographic printer that is based on the technology used by photocopiers. 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 electrified charge is removed from the drum and the excess toner is collected. By omitting the final step and repeating only the toner application and paper handling steps, the printer can make multiple copies.
· DAISY WHEEL PRINTER:
Daisy wheel printer are some times called letter quality printer because they are often used to produce attractive correspondence. The D.W.P is a flat circular device made of metal with character embossed on it. As this wheel spins at a very high speed the hammer hits the specific character against the ribbon which presses against the paper.
· THERMAL TRANSFER PRINTER:
It is a kind of non-impact printer. In electro-thermal printing, characters are burned on to a special paper by heated rods on a print heat. They transfer ink from a wax-based ribbon onto plain paper. These printer can support high quality graphic.
· INK – JET PRINTER:
It is a kind of non-impact spray small dots of electrically charged ink onto a paper to form images. Ink jet printers are flexible enough to be used as plotters.