Introduction

Early developments

Xerography, from the Greek words for dry, xeros, and writing, graph in, describes the phenomena by which images are produced by the creation of electrostatic charge patterns that are then made visible by charged marking particles. Processes by which electrostatic charges are used for image reproduction can be traced to the formation of charge patterns by Lichtenberg (1778), which still bear his name. Lichtenberg images were originally prepared by scattering dust on the surface of resin insulators that had previously been exposed to an electric spark. The first page of Lichtenberg’s original paper is illustrated in Fig. 1.A decade later, Villarsy (1788) was able to determine the polarity of Lichtenberg figures by using a mixture of red pb and S powders. The first practical demonstration of electrostatic recording was by Ronalds in the early 1840s. the instrument produced by Ronalds (1842) was called an electrograph and involved the movement of a stylus contact, which was connected to a lightning rod, across an insulating resin surface. The charge pattern, induced by the atmospheric electricity, was made visible by dusting the surface with charged powder particles.

During the latter part of the nineteenth and early part of the twentieth centuries, there were a number of observations in which electrostatic images were made visible: Riess (1853), Swan (1897), Konig (1899), Burker (1900), and Baker (1922). All had in common the displacement of powder, dust, or smoke to charged surfaces. The first sustained efforts for the reproduction of electrostatic images.