Friday, 24 February 2017

Plotters !

A plotter is a printer that interprets commands from a computer to make line drawings on paper with one or more automated pens. Unlike a regular printer, the plotter can draw continuous point-to-point lines directly from vector graphics files or commands. There are a number of different types of plotters: a drum plotter draws on paper wrapped around a drum which turns to produce one direction of the plot, while the pens move to provide the other direction; a flatbed plotter draws on paper placed on a flat surface; and an electrostatic plotter draws on negatively charged paper with positively charged toner.Plotters were the first type of printer that could print with color and render graphics and full-size engineering drawings. As a rule, plotters are much more expensive than printers. They are most frequently used for CAE (computer-aided engineering) applications, such as CAD (computer-aided design) and CAM (computer-aided manufacturing).
A plotter consists of an arm that moves across the paper on which the diagram or graph needs to be drawn . Apen moves along the arm. and the arm itself moves relative to the paper. Acombination of the two thus provides movement along the horizontal and vertical axes.
In some plotters, the paper is held station ary while the arm and the pens move over it. This is called a flat-bed plotter. In the other type of plotter, the paper is wrapped around a drum and anchored at anchored at both ends. The drum rotates while the pen moves laterally along a fixed rail. This is called a drum plotter.
To draw clear and high-qualit diagrams, a plotter needs high-quality pens with special inks of different colors. A plotter can be connected to a PC through the parallel port. A plotter is more software-dependent than any other peripheral, and needs much more instructions than printer for producing output.
Plotter are used in applications like CAD, which requir high-quality graphics on paper. Many of the plotters now available in the market are desktop models that can be used with PCs. Businesses typically use plotters to present an alysis in terms (bar charts, graphs, diagrams, etc.) as well as for engineering drawings.
Two commanly type plotters are:
§  Drum Plotters
§  Flatbed Plotters


Drum Plotters
In this plotter the pen moves in the horizontally and the drum rolls on the other axis. Generally it is a graphical output device, and it is generally used to plot drawings. the width of the plot is limited by the length of the drum. It is the first graphical output device produced to print large scaled engineering drawings.Colored prints can be made if you use colored ink.This electronic equipment used to plot large sized drawings on a tracing sheet. Plans for building ( architectural drawing) , engineering drawings , dress models ETC are drawn using suitable packages. These drawings are plotted on a tracing sheet, which can be used to produce a large no of blue prints.
It is very good for line drawings but it is very slow. Here the pen is held in gantry and it moves in x-axis and the paper moves on y-axis.



Flatbed Plotters
This is a plotter where the paper is fixed on a flat surface and pens are moved to draw the image. This plotter can use several different colour pens to draw with. The size of the plot is limited only by the size of the plotter's bed.


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