Know Your Computer
OUTPUT


Examples of Output Devices

Plotters

Plotters are large-scale printers that are very accurate at reproducing line drawings. They are commonly used for technical drawings such as engineering drawings or architectural blueprints. Pen plotters have an ink pen attached to draw the images, and electrostatic plotters work similarly to a laser printer. Pen plotters are of two types: flat bed plotters and drum plotters.

Flat Bed Pen Plotter

To the right is a plotter where the paper is fixed on a flat surface and pens are moved to draw the image. The paper remains stationary and the printer moves pens across the paper to draw the image. This plotter can use several different colored pens to draw. The size of the plot is limited only by the size of the plotter's bed.

The pen and the penholder only move in one direction, namely the Y-direction (a movement to the left and right sides of the plotter, horizontal to the floor). Drawing onto the paper is achieved by a coordination of the pen movement in the Y-direction with the movement of the paper in the X-direction (a movement up and down, vertical to the floor).

 

Drum Plotter (Upright Pen Plotter)

Drum plotters, also called upright plotters, are vertically positioned. They have a drum that the paper rolls on. Drum plotters usually make more noise and are more compact than flatbed plotters. The pen and the penholder are attached to a beam horizontally above a table of a certain width and length.

The pen can be moved in the Y-direction (a movement along the length of the beam). The beam itself can be moved in the X-direction (a movement of the beam along the length of the plotter). Drawing onto the paper is achieved by a coordination of the beam and pen movements in the X- and Y-directions respectively. The paper is pulled across the table for plotting.

Inkjet Plotters

Also referred to as raster plotters, inkjet plotters are typically upright in design. The vector information is rasterized or converted to a bitmap (a series of horizontal lines where a pixel is set to zero (do not draw a dot) or one (draw a dot). The print head is not a pen but rather an inkjet head that sprays ink on the paper, without touching the paper. The plot-out is achieved by the head moving in the Y-direction (a movement to the left and right sides of the plotter, horizontal to the floor). The plot-out is constructed from a series of horizontally printed strips.

Projector

LCD (Liquid Crystal Display) /DLP (Digital Light Processing) projectors projects the output image onto a wall or a screen so that people can see the image clearly. An LCD projector, which uses liquid crystal display technology can produce lower-quality images only. A DLP projector, which uses tiny mirrors to reflect light can produce much better images even in a well-lit room.

Audio Output Devices

Audio output devices are the components of a computer that produce music, speech, or other sounds. Two commonly used audio output devices are speakers and headsets. Audio output devices are ideal for visually impaired people. Audio output devices are not suitable for use in noisy environments. They are also not suitable for use in very quiet environments where other people are working (e.g., libraries).