In some designs the charge pattern is applied by styluses directly to paper that has been specially treated. An alternative approach is to apply the pattern to a metal drum with a suitable coating such as aluminum oxide. The pattern is made visible by washing the paper or drum with a colloidal suspension of charged particles of pigment. The image on a drum is transferred to plain paper by pressure and the application of an electric field. The particles of pigment are very fine and thus penetrate the fibers of the paper and form a permanent image. The charge can also be applied to the drum by the controlled projection of ions.
In some literature the term is used to refer to all printers in which an electrostatic image is formed as one of the steps in the process, including electrophotographic printers.
"electrostatic printer." A Dictionary of Computing. . Encyclopedia.com. (August 15, 2018). http://www.encyclopedia.com/computing/dictionaries-thesauruses-pictures-and-press-releases/electrostatic-printer
"electrostatic printer." A Dictionary of Computing. . Retrieved August 15, 2018 from Encyclopedia.com: http://www.encyclopedia.com/computing/dictionaries-thesauruses-pictures-and-press-releases/electrostatic-printer