Expandable supplies container capable of measuring residual amount of expandable supplies

摘要

An expendable container of the invention has a function of measuring a residual quantity of an expendable kept therein. The expendable container has: an expendable tank that keeps the expendable therein and has a piezoelectric element attached thereto; a detection signal generation circuit that charges and discharges the piezoelectric element and generates a detection signal including information, which represents a cycle of remaining vibration of the piezoelectric element after the discharge; and a control module that controls the charge and the discharge of the piezoelectric element. The cycle is used to determine whether the residual quantity of the expendable kept in the expendable tank is greater than a preset level. The control module varies a discharge characteristic of the piezoelectric element.