RESONANT-FREQUENCY MEASUREMENT OF ELECTROPHOTOGRAPHIC DEVELOPER DENSITY

摘要

Developer density is measured in an electrophotographic system. First and second electrodes are disposed to define a working volume between them through which developer passes without contacting the first electrode, wherein the electrodes are electrically insulated from each other by the working volume. One terminal of an AC voltage (current) source having a selected frequency is connected to one of the electrodes. An inductor is connected in series (parallel) with the voltage source, so that the source provides the AC bias (current) across the electrodes through (across) the inductor. The AC is applied and the current (voltage) across the electrodes is measured. The density of the developer in the working volume is automatically determined using a processor responsive to the measured current (voltage) and the applied bias (current).