Patent ID: 8256869

Claim:
An imaging device comprising: an ink receiving surface of a drum that is movably supported within the imaging device; at least one printhead including a plurality of ink jets, each ink jet being configured to eject drops of ink on the ink receiving surface of the drum; a first electrode positioned adjacent the ink receiving surface, the first electrode being configured to output capacitance signals indicative of a capacitance in a first gap between the first electrode and the ink receiving surface of the drum; a second electrode positioned adjacent the ink receiving surface, the second electrode being configured to output capacitance signals indicative of a capacitance in a second gap between the second electrode and the ink receiving surface of the drum; and a controller operatively connected to the first electrode and the second electrode to receive the capacitance signals from the first and the second electrodes, the controller being configured to: operate at least one ink jet in the plurality of ink jets to eject drops of ink to form at least one test band on the ink receiving surface of the drum; rotate the drum to slew the ink receiving surface at a predetermined rate of speed with the at least one test band formed on the ink receiving surface of the drum; average a first test band capacitance and a second test band capacitance, the first test band capacitance being identified from a first round of capacitance measurements made with reference to a test band capacitance signal from the first electrode that is indicative of a capacitance with the test band on the image receiving surface being in the first gap and with reference to a baseline capacitance signal from the second electrode indicative of a capacitance in the second gap with no ink being on the image receiving surface in the second gap, and the second test band capacitance being identified from a second round of capacitance measurements made with reference to a baseline capacitance signal from the first electrode that is indicative of a capacitance in the first gap with no ink being on the image receiving surface in the first gap and with reference to a test band capacitance signal indicative of a capacitance in the second gap with the test band being on the image receiving surface in the second gap; and modify an operating parameter of the imaging device with reference to the average of the first test band capacitance and the second test band capacitance.