Wednesday, September 2, 2009

OUTPUT DEVICES TECHNOLOGY






In computing, input/output, refers to the communication between an information processing system (such as a computer), and the outside world – possibly a human, or another information processing system. An output device is any piece of computer hardware equipment used to communicate the results of data processing carried out by an information processing system (such as a computer) to the outside world. Inputs are the signals or data received by the system, and outputs are the signals or data sent from it.

There are many types or examples of printer, so, ONLY five examples of printer that have been chosen to make comparison among them,there are:-


The criteria that will be compared among them are:-
  • The meaning.
  • Process of working.
  • Advantage.
  • Disadvantage.


Ink-jets (bubble-jets) printers are the least expensive and produce excellent colour output, which makes them popular choices for home users. Inkjet printers form an image that is composed of tiny dots.

The process of Ink-jets (bubble-jets) printers works by a drop-on-demand inkjet printing method where ink drops were ejected from the nozzle by the fast growth of an ink vapor bubble on the top surface of a small heater.

The advantage- compared to earlier consumer-oriented are first, they are quieter in operation than impact dot matrix or daisy wheel printers

The disadvantage is the ink is often very expensive.


Laser printer is a type of printer that utilizes a laser beam to produce an image on a drum. The light of the laser alters the electrical charge on the drum wherever it hits.

The process of laser printer works when a corona wire (in older printers) or a primary charge roller projects an electrostatic charge onto the photoreceptor (otherwise named the photoconductor unit), a revolving photosensitive drum or belt, which is capable of holding an electrostatic charge on its surface while it is in the dark. An AC bias is applied to the primary charge roller to remove any residual charges left by previous images.

The main advantage of laser printers is speed, precision and economy.

The disadvantages are health risk, and precautions.


The Impact (Dot-matrix) printers is a type of computer printer with a print head that runs back and forth, or in an up and down motion, on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like a typewriter.

The process of Impact (Dot-matrix) works- each dot is produced by a tiny metal rod, also called a "wire" or "pin", which is driven forward by the power of a tiny electromagnet or solenoid, either directly or through small levers (pawls). Facing the ribbon and the paper is a small guide plate (often made of an artificial jewel such as sapphire or ruby pierced with holes to serve as guides for the pins.

The advantage of Dot matrix printers is, like any impact printer, can print on multi-part stationery or make carbon-copies

The disadvantage is pen plotters have essentially become obsolete, and have been replaced by large-format inkjet printers and LED toner based printers.


The Dye Sublimation is a computer printer which employs a printing process that uses heat to transfer dye to a medium such as a plastic card, paper, or fabric.

The process of works- In a dye-sublimation printer the printing dye is heated up until it turns into a gas, at which point it diffuses onto the printing media and solidifies. Prior to printing, the dye is stored on a cellophane ribbon. The ribbon is made up of three colored panels (cyan, magenta, and yellow) and one clear panel which hold the lamination material for the overcoating. Each colored panel is the size of the media that is being printed on; for example, a 6" by 4" dye sub printer would have four 6" by 4" panels. During the printing cycle, the printer rollers will move the media and one of the colored panels together under a thermal printing head, which is usually the same width as the shorter dimension of the print media

The advantage of dye-sublimation printing has been the fact that it is a continuous-tone technology, where each dot can be any color

The disadvantage- each of the colored panels of the ribbons, and the thermal head itself, must match the size of the media that is being printed on


The plotter is a vector graphics printing device to print graphical plots, that connects to a computer. There are two types of main plotters.

The process of plotter works is when, Pen plotters print by moving a pen across the surface of a piece of paper. This means that plotters are restricted to line art, rather than raster graphics as with other printers. Pen plotters can draw complex line art, including text, but do so very slowly because of the mechanical movement of the pens. Pen Plotters are incapable of creating a solid region of color; but can hatch an area by drawing a number of close, regular lines.

The advantage- -Plotters are used primarily in technical drawing and CAD applications, where they have the advantage of working on very large paper sizes while maintaining high resolution.

The disadvantage is Impact printers are usually noisy, to the extent that sound dampening enclosures are available for use in quiet environments.


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