The invention provides a method of controlling an ink jet recording
apparatus on which a liquid container is to be detachably mounted, the
liquid container having a piezoelectric device for detecting the liquid.
The method includes the steps of: detecting a characteristic value of the
piezoelectric device by a detection section provided inside or outside of
the ink jet recording apparatus; judging whether or not the
characteristic value satisfies a predetermined condition by a judging
section provided inside or outside of the ink jet recording apparatus;
and controlling the ink jet recording apparatus so that the ink jet
recording apparatus is set in an operable or a non-operable state based
on a result of the judging step. It is possible to judge whether or not
the piezoelectric device is normally operated, to confirm the liquid of
the predetermined volume is contained in the liquid container, to detect
deficiencies of the liquid container and the piezoelectric device, and to
detect a gradient of the liquid container.