CONCENTRATION DETECTOR FOR COLORED TONER

摘要

Apparatus for detecting concentrations of colored toner particles in the presence of black or other absorbing toner particles including a light source, a light detector having a field of view of less than about ~10 degrees and preferably less than ~5 degrees, apparatus for supplying a dispersion of colored toner particles optionally containing undesirable contamination by black toner particles between the light source and the detector and computing circuitry operative for determining the concentration of the colored toner particles utilizing output from the light detector.