Electrophotographic measurement system

摘要

A first embodiment of a measurement system provides an indication of performance of an electrophotographic process. The first embodiment includes a charge measurement device coupled to a developing device and a high voltage power supply. The charge measurement device generates a signal corresponding to the net charge transferred between the high voltage power supply and the developing device during an imaging operation. The measured charge transfer is compared to an estimated charge transfer to determine if the electrophotographic process is operating correctly. The estimated charge transfer is determined by multiplying an estimate of the mass of the toner transferred during an imaging operation by an average value of toner charge to mass ratio. A sufficiently large difference in the magnitude between the measured charge transfer and the estimated charge transferred indicates that the electrophotographic process is not operating correctly. A second embodiment of measurement system includes a charge measurement device coupled to a photoconductor to measure the net charge transfer between the photoconductor and ground during an imaging operation. The net charge transfer is compared to the estimated charge transfer to determine whether the electrophotographic process is operating correctly. A third embodiment of the measurement system includes a voltage measuring probe to measure a voltage on the surface of a photoconductor. A controller determines if the measured surface voltage on the photoconductor is within a range of voltages occurring during normal operation of the electrophotographic process.