Patent ID: 6874861

Claim:
A printing device configured to print a printing fluid onto a printing medium, comprising: a printing fluid reservoir configured to hold a volume of the printing fluid; a print head assembly configured to transfer the printing fluid to the printing medium; a conduit fluidically connecting the printing fluid reservoir to the print head assembly; and a printing fluid detector associated with the conduit, wherein the printing fluid detector includes a first electrode and a second electrode configured to be in contact with printing fluid in the conduit, a power supply configured to apply an alternating supply signal to the first electrode, and detector circuitry configured to measure a plurality of measured impedance values related to the presence of printing fluid within the conduit by comparing the alternating supply signal with a plurality of detected signals that have been modified from the applied signal by an impedance characteristic of the printing fluid, to determine a variability of the plurality of measured impedance values, and if the variability of the plurality of measured impedance values is equal to or below a predetermined variability, then to determine a temperature of the printing fluid based upon the plurality of measured impedance values.