Liquid cartridge including pivotable plate member for optical detection

A liquid cartridge attachable to a printer in an attached posture by being moved in a front-rear direction crossing an up-down direction along a gravitational direction, the liquid cartridge comprising:

• a cartridge case defining a liquid storage chamber therein;
• a liquid supply portion protruding frontward from a front surface of the cartridge case and configured to supply liquid stored in the liquid storage chamber to an outside of the liquid storage chamber;
• a residual-amount detecting portion configured to change a state of incident light according to an amount of the liquid stored in the liquid storage chamber, the residual-amount detecting portion comprising an optical access portion accessible by light traveling in a left-right direction crossing the up-down direction and the front-rear direction in the attached posture, the optical access portion being positioned above the liquid storage chamber in the attached posture;
• and
• a plate member pivotable about a pivot axis between a first position and a second position, the pivot axis extending in the up-down direction in the attached posture, the plate member being positioned above the liquid storage chamber and frontward of the optical access portion in the attached posture,
• wherein, in the attached posture,
• the plate member extends in the front-rear direction at the first position, and
• the plate member extends in a direction crossing the front-rear direction at the second position.