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A plotter is a computer printing device for printing vector graphics. In the past, plotters were widely used in applications such as computer-aided design, though they have generally been replaced with wide-format conventional printers, and it is now commonplace to refer to such wide-format printers as plotters. A plotter is a pen-based output device that is attached to a computer for print large-format graphs or maps such as construction maps or engineering drawings. The images are created by a series of many straight lines. It is used to draw high-resolution graphs. It is a special output device used to produce hard copies of graphs and designs on paper.
Plotters are divided into two types:
- Drum Plotter
- Flatbed Plotter
A drum plotter is also known as Roller Plotter. It consists of a drum or roller on which a paper is placed and the drum rotates back and forth to produce the graph on the paper. The drum rotation is under the control of plotting instructions sent by the computer. In this plotter the pen is moved vertically, i.e. along the Y-axis and the paper wrapped on the drum is moved horizontally, i.e. along the X-axis. The movement of paper is backward or forward direction to produce a graph or an image. In case, a horizontal line is to be draw, the horizontal movement of a pen is combined with the vertical movement of a page via the drum. It can draw the curves by creating a sequence of very short straight lines.
The figure is shown below shows the drum type. It consists of one or more pens that are mounted on a carriage and this carriage is horizontally placed across. It also consists of a mechanical device known as a Robotic Drawing Arm that holds a set of colored ink pens or pencils. The Robotic Drawing Arm moves side to side as the paper is rolled back and forth through the roller. In this way, a perfect graph or map is created on paper. This work is done under the control of the computer. Drum Plotters are used to produce continuous output, such as plotting earthquake activity
A flatbed plotter is also known as Table Plotter. It plots on paper that is spread and fixed over a rectangular flatbed table. In this type, the position of the paper is kept constant and the pens moved around in various directions to draw graphs and images. The flatbed plotter uses two robotic drawing arms, each of which holds a set of colored ink pens or pencils. The drawing arms move over the stationary paper and draw the graph on the paper.
Typically, the plot size is equal to the area of a bed. The plot size maybe 20- by-50 feet. It is used in the design of cars, ships, aircraft, buildings, highways, etc. The flatbed plotter is very slow in drawing or printing graphs. The large and complicated drawing can take several hours to print.
The main reason of the slow printing is due to the movement mechanical devices.
Today, mechanical plotters have been replaced by thermal, electrostatic, and inkjet plotters. These systems are faster and cheaper. They also produce large-size drawings. The figure is shown below shows the flatbed type.
Comparison Between Printer and Plotter
Plotters are similar to printers, but plotter draw lines using a pen. The plotters an produce continuous lines whereas the printer can only simulate lines by printing a closely spaced series of dots. Multicolor plotters use different colored pens to draw different colors. Color plots are made by using four pens cyan, magenta, yellow and black.
Some of the main uses are given below:
- Use in computer Aided Design (CAD) and Computer-Aided Manufacturing (CAM) applications.
- It is Use in printing the plans for houses or car parts
- Use programs like auto CAD to give graphic outputs.