When Chester Carison invented xerography, he employed sulfur and anthracene as photoconductors.
Although the initial commercialization of his idea relied on inorganic photoconductors, the current
trend is towards use of organic photoconductors because of their material variety, economy and
flexibility. High speed copying and printing machines use belts coated with organic photoreceptors,
while personal copiers and printers use aluminum drums dip-coated with organic photoreceptors.
Multilayered, organic photoreceptors are now routinely mass produced by the millions with both
visible sensitivity for copiers and infrared sensitivity for printers.
This paper presents a brief overview of key photoreceptor properties and follow with a survey of
electronic organic materials of current interest. The photodischarge characteristic is determined
mainly by three factors: the photogeneration, the injection, and the transport of charge carriers. These
functions can be accomplished by separate electronic material layers; photogeneration by organic
pigments and charge transport by aromatic-amine electron-donor molecules. The photogeneration
layers are usually fabricated by solvent coating a dispersion of a pigment in a polymeric binder while
the charge transport layers are solvent coated to form a solid solution of the aromatic amine in a
polymeric binder. Examples and characteristics of organic pigments and charge transport molecules of
current interest are discussed.