Patent ID: 9079414
Filing Date: 2015-07-14
Classification: B41J

Abstract:
1. An inkjet printer comprising: a fluids container; a level measurement facility external to said container for determining fluid levels within said container, said level measurement facility includes a vertical array of discrete sensors adjacent to an exterior surface of said container and a sensing circuit into which each of said sensors may be sequentially switched to determine solely whether a sensor is above or below a particular fluid level in said container, wherein said sensing circuit is configured as a frequency oscillation circuit wherein the frequency of oscillation is defined by circuit capacitance and wherein a change of frequency above a pre-determined threshold between two successive measurements is interpreted as indicating a change from fluid to air between the levels of the sensors giving rise to said successive measurements; and an earth plate separate from, and arranged beneath, said container such that said earth plate is not electrically coupled to the fluid.