Electrostatic Plotters:

In these, a negative charge is placed on those parts of white papers that are to be black, and then flows positively charged black toner over the paper. It leads to the adhering of the toner particles to the paper where the charge has been deposited. In colour electrostatic plotters, the three subtractive primary colours magenta, cyan and yellow and black are applied to the medium in four successive passes. The medium is rebound among applications of each colour. Others utilize multiple heads to deposit all of the colours in the single pass. Electrostatic plotters are frequently faster than pen plotters. Alternatively, pen plotters create images with higher contrast, as they deposit the toner even in areas where the paper is not negatively charged.