Patent ID: 6474156
Filing Date: 2002-11-05
Classification: B41J,G01F

Abstract:
A method of determining an amount of a liquid existing in a container, comprising the steps of:integrally forming a resonance circuit including a first coil, a second coil, and a plurality of electrodes on at least one side of the container; providing a drive coil and a sense coil outside of the container; applying a voltage having a preselected frequency to the drive coil to induce a voltage having a preselected frequency in said first coil of said resonance circuit; inducing, based on the voltage induced in said resonance circuit, a voltage having a preselected frequency in said sense coil from said second coil; measuring the voltage induced in said sense coil; and comparing the voltage induced in said sense coil and a preselected voltage value to determine an amount of a liquid in the container.