Abstract: There is provided a method for use with a printing machine having a movable imaging member and a projecting system for modulating a beam and projecting an image into the movable imaging member. The printing machine further includes a developer for application of developer material to the image projected onto the movable imaging member for transfer of the image to a print media sheet.

Abstract: An apparatus for monitoring and controlling electrical parameter of an imaging surface, the monitoring controlling apparatus including a patch generator for recording a first control patch at a first voltage level and a second control patch at a second voltage level on the imaging surface; electrostatic voltmeter for measuring voltage potentials associated with the first control patch and second control patch. A processor, in communication with the patch generator, calculates the electrical parameters of the imaging surface from the measured voltage potentials from the first and second control patches. The processor determines a deviation between the calculated electrical parameters values and setup values. Then, the processor produces and sends a feedback error signal to the patch generator if the deviation exceed a threshold level. The patch generator records a third control patch at a third voltage level on the imaging surface upon reception of the error signal. The ESV senses the third control patch.