The nondestructive measurement of the charge-to-mass ratio of an insulating tone layer present on a photoconductor

Nondestructively measuring the charge present in a toner layer based upon a noncontacting measurement of the potential across the layer and the solution of Poisson´s equation for the toner layer is addressed. The former is easily accomplished using commercially available electrostatic voltmeters. The latter requires detailed knowledge of the toner layer morphology. Solid-area continuous-tone images of various densities have been studied microscopically to determine toner stack height and volume-mass density. From these data, the toner charge-to-mass ratio is determined. An adjustment of the data for stack height to account for the surface-layer topology (roughness) yields a final accuracy of about 6%