Patent ID: 8567895

Claim:
An abnormality judgment apparatus of a liquid supply system which supplies liquid from a liquid tank to a liquid ejection head via a liquid flow channel, the abnormality judgment apparatus comprising: a pressure change application device which applies a pressure change to the liquid flow channel; first and second pressure measurement devices which measure a pressure in the liquid flow channel; and an abnormality judgment device which performs abnormality judgment and identification of an abnormal location in the liquid supply system, according to measurement values measured by the first and second pressure measurement devices before and after the pressure change is applied by the pressure change application device, wherein if the measurement value obtained by one of the first and second pressure measurement devices changes in a direction which is same as a direction in which the pressure change is applied by the pressure change application device, and the measurement value obtained by the other of the first and second pressure measurement devices changes in a direction opposite to the direction in which the pressure change is applied by the pressure change application device or does not change, then the abnormality judgment device identifies the other of the first and second pressure measurement devices as the abnormal location.