APPAREIL AUTOMATIQUE DE CONTROLE DE DEVELOPPABILITE OU DE CAPACITE DE DEVELOPPEMENT DU REVELATEUR

摘要

A developability control system for a xerographic reproducing machine. The system includes two parallel-spaced NESA glass plates through which two-component developer material, including toner and carrier, flows. The plates are connected in a circuit wherein each is electrically charged alternately for equal periods of time for attracting and repelling toner. A light source is located at one side of the two plates while a photocell is located on the other side to sense the optical density of the sum toner deposit on the two plates at all operating times. This sensing is compared with light received by a second photocell, separated from the same light source by a filter, to cause the dispensing of toner to the developer at appropriate times.