Patent ID: 8066343
Filing Date: 2011-11-29
Classification: B41J

Abstract:
1. A liquid detecting apparatus that drives a liquid detecting section that outputs two detection signals having phases opposite to each other in accordance with the amount of liquid, the liquid detecting apparatus comprising: a driving section that outputs a driving signal to the liquid detecting section; a differential amplifying section that performs differential amplification on said two detection signals that are output from the liquid detecting section on the basis of the driving signal so as to output a differential amplification detection signal; and a signal detecting section that makes a judgment as to whether the amount of liquid is not less than a predetermined amount or not by means of the differential amplification detection signal input from the differential amplifying section, wherein the liquid detecting section has a first electrode and a second electrode; and the differential amplifying section has the first input portion to which the first electrode of the liquid detecting section is electrically connected and the second input portion to which the second electrode of the liquid detecting section is electrically connected, and wherein one of the first electrode of the liquid detecting section and the second electrode of the liquid detecting section is provided at a position that is more susceptible to an external noise than a position at which the other of the first electrode of the liquid detecting section and the second electrode of the liquid detecting section is provided; and a high-pass filtering section has a capacitor portion having the same capacitance as that of the liquid detecting section, the capacitor portion being provided at a side where one of the first electrode of the liquid detecting section and the second electrode of the liquid detecting section that is more susceptible to the external noise than the other thereof is electrically connected.