Liquid detecting apparatus, liquid-amount detecting apparatus, liquid detecting method, and liquid-amount detecting method

A liquid-amount detecting apparatus for detecting the amount of a liquid contained in at least one container, the liquid detecting apparatus comprising:

• a liquid detecting circuit comprising an electrode unit formed by a pair of electrodes that is to be disposed in contact at least partially with the liquid in the container, the pair of electrodes being electrically connected to each other when the pair of electrodes is in contact with the liquid;
• a source impedance;
• and an alternating-current signal source;
• wherein the liquid detecting circuit inputs an alternating-current signal not containing a direct-current component to the electrode unit through the source impedance, outputs a signal representing a status of electrical connection between the pair of electrodes, and outputs a binary signal representing the presence or absence of an electrical connection between the pair of electrodes based on the output signal;
• and
• a determining means for determining the presence or absence of the liquid at the electrode unit based on the binary signal output from the liquid detecting circuit and wherein the electrode unit is provided in each of a plurality of containers, and wherein the liquid detecting circuit sequentially outputs, by time division, signals representing a status of electrical connection between each of the respective pairs of electrodes in the plurality of containers.