Selenium Coatings in the Thickness Range 0.2 to 2.5 μ for Xerography

Abstract

The electro-photographic behaviour of vitreous selenium coatings of thickness between 0-2 and 2-5μ deposited on cadmium oxide coated glass plates has been examined in respect to charge potential accepted and charge decay both in the dark and on exposure to tungsten light. The sensitometry of such coatings when used in conjunction both with dry powder and with liquid dispersion development techniques has also been studied.

The production of both xerographic and xero-radiographic images on these thin coatings is feasible and such images, although of lower contrast, possess certain advantages over those formed on selenium coatings of normal thickness. For instance they are suitable for transmission viewing and transmission sensitometry and they are practically free from artefacts and hence enable the high instrinsic resolving power of the selenium coating to be utilized to the fullest possible extent. The thinness of the coatings permits them to be removed chemically leaving the fixed image produced by liquid development intact on the base plate.