A plotter is a specialised output device designed to produce high-quality graphics in a different types of colors. Principal types of plotters are especially useful for creating maps and architectural drawings, although they may produce less complicated charts and graphs. The three principal kinds of plotters are pen, electrostatic, and thermal.
A pen plotter, flatbed types of plotters, is designed so that paper lies flat on a table like surface (flatbed plotter) or is mounted on a drum (drum plotter). Between 1 and 4 pens move across the paper, the paper moves beneath the pens. This is the most popular type of plotter; can produce up to four colors.
Instead of using pens, a plotter uses electrostatic changes to create tiny dots on specially treated paper. The paper is run through a developer to produce the image, which may be four-color.