APPARATUS FOR SENSING ELECTROSTATICALLY CHARGED PARTICLES

摘要

A sensing apparatus and material in which the developability of electrostatically charged particles in a mixture of particulate material may be measured. The apparatus includes a transparent member (62) positioned closely adjacent to a developer roller (44) of an electrophotographic printing machine. Electrostatically charged particles are attracted from the particulate mixture being transported by the developer roller (44) to the member (62). A beam of energy is transmitted through the member (62) from source (64). The intensity of the internally reflected beam is detected by detected (66) and a signal generated indicative of the quantity of charged particles adhering to the member.