Patent ID: 7134331
Filing Date: 2006-11-14
Classification: B41J,G01F

Abstract:
1. A liquid holding tank for a printer comprising: a container which contains a liquid that is used in a printer; a liquid detecting apparatus, wherein at least a part of said liquid detecting apparatus is disposed at said container, and further wherein said liquid detecting apparatus is comprised of: a liquid detecting circuit comprising a plurality of electrode units disposed in said at least one container in a direction in which a surface of the liquid falls, each unit formed by a pair of electrodes separated from each other in a direction substantially perpendicular to the direction in which the surface of the liquid falls, and the members of each pair being electrically connected to each other when the pair of electrodes is in contact with the liquid; a source impedance; and a single alternating-current signal source; wherein the liquid detecting circuit causes an alternating-current signal not containing a direct-current component to be selectively input to each electrode unit through the source impedance, and outputs binary signals representing the presence or absence of an electrical connection between each pair of electrodes; and a determining unit for determining the presence or absence of the liquid at each electrode unit based on the binary signals output from the liquid detecting circuit, wherein the liquid detecting circuit selectively connects the single alternating-current signal source to a node of the electrode unit.