Patent ID: 6744996
Filing Date: 2004-06-01
Classification: G03G

Abstract:
A method for determining the percentage of toner solids remaining in liquid printing ink within a liquid printing ink storage device or liquid ink use cartridge comprises:providing an electrical signal generator in signal communication with the storage device or cartridge; providing a first electrode electrically connected to the signal generator, the first electrode in electrical contact with the liquid printing ink; providing a second electrode at a predetermined gap distance across the liquid printing ink from the first electrode, the second electrode in electrical contact with the liquid printing ink and connected to an electrical signal detector; transmitting an electrical current signal having an amplitude from the signal generator to the first electrode at 0.1 to 10 MHz; detecting the electrical current signal or its absence with the electrical signal detector, determining the amplitude or absence of the electrical current signal at the second electrode, determining the dielectric constant from the electrical current signal and generating a low toner solids warning signal in response to the amplitude being detected at the second electrode at an amplitude below a predetermined minimum level.