Patent ID: 8246151

Claim:
A liquid supply device comprising: a liquid cartridge comprising a liquid chamber configured to store a liquid therein; a cartridge mounting portion, wherein the liquid cartridge is configured to removably mount to the cartridge mounting portion; a level detector configured to detect a position of a liquid surface of the liquid stored in the liquid chamber, wherein the position of the liquid surface of the liquid is detected to be at one of at least three liquid surface levels; and a determiner configured to determine that the liquid supply device is in an abnormal state when the determiner determines that the position of the liquid surface of the liquid detected by the level detector has moved by two or more liquid surface levels in a particular direction away from a bottom surface of the liquid chamber, and the determiner is configured to determine that the liquid supply device is not in the abnormal state when the determiner determines that the position of the liquid surface of the liquid detected by the level detector has moved by one or fewer liquid surface level in the particular direction.