Patent ID: 7008034

Claim:
A method of controlling an ink jet recording apparatus on which a liquid container is able to be detachably mounted, said liquid container having a container body containing a liquid supplied to a recording head discharging an ink droplet from a nozzle opening and a piezoelectric device for detecting said liquid within said container body, comprising the steps of: detecting a characteristic value of said piezoelectric device by a detection section provided inside or outside of said ink jet recording apparatus; judging whether or not said characteristic value satisfies a predetermined condition by a judging section provided inside or outside of said ink jet recording apparatus; and controlling said ink jet recording apparatus so that said ink jet recording apparatus is set in an operable state or in a non-operable state based on a result of said judging step, wherein said piezoelectric device has a vibrating portion which comes into contact with said liquid in said container body via a cavity, said cavity defining an area of said vibrating portion, wherein said characteristic value is detected based on a signal output from said piezoelectric device, said signal indicating a residual oscillating state of said vibrating portion of said piezoelectric device, said characteristic value changing based on phenomenon that said residual oscillating state changes corresponding to a liquid consuming state.