Consumer Electronics

XEROGRAPHIC PROCESS

The basic steps in the xerographic process are depicted in Fig. 45.1. Charging or sensitization of the photoconductor to a uniform surface potential of 800-1000 V is usually accomplised by a corotron. Literally a thin wire, stretched between terminals parallel to the photoconductor surface, and driven at approximately 8000 V, the corotron emits a corona of ions which deposit on the photoconductor surface. The charged photoconductor must be kept in the dark to prevent discharge.

Exposure of the sensitized photoconductor to light reflected from the original to be copied generates the required electrostatic image. Voltage decay occurs via photon absorption by the photoconductor surface with the creation of an electron-hole pair. ...