Browse Prior Art Database

Original Publication Date: 1980-Jun-30
Included in the Prior Art Database: 2004-Apr-02

Publishing Venue

Xerox Disclosure Journal


In an automatic developability system, a pair of parallel plates are positioned so as to be in the path of flow of developer material. One of the plates is alternatively electrically biased at different potentials in a finger pattern to attract toner particles thereto. A light source transmits light rays through the plates, which are made from a transparent conductive material such as NESA glass. The light rays transmitted through the plates are received by a photosensor. The intensity of the light rays received by the photoreceptor is a measure of the density of particles deposited on the electrically biased plate. This corresponds to the concentration of toner particles within the developer material. The cascading developer generates a low level of free toner which eventually builds up on the unbiased plate. In order to assure proper operation of such a device, this plate can be cleaned by placing partial obstruction in the path of the flowing developer so that a few of the developer particles strike the plate and maintain it free of toner.