Patent ID: 8850884

Claim:
A liquid tank comprising: a liquid container section storing liquid; and a detector detecting volume of the liquid stored in the liquid container section, the detector including: a first board having, on a front face thereof, a pair of detection electrodes for detecting a stray capacitance, the pair of detection electrodes directly or indirectly contacting with the liquid inside the liquid container section; a second board having a shielding electrode and arranged on a back face side of the first board; and a liquid pump drawing up the liquid stored inside the liquid container section, wherein the detector includes, on a back side of the first and second boards, a printed board with a volume measurement circuit mounted thereon, the printed board being configured to measure the stray capacitance between the pair of detection electrodes, and wherein the volume measurement circuit includes a memory section storing an operation history of the liquid pump, and a calculation section calculating, based on the operation history stored in the memory section, an amount of the liquid that has been drawn up, and calculate the volume of the liquid based on both the amount that has been drawn up and the stray capacitance.