Patent ID: 8851646

Claim:
A cartridge for storing liquid to be supplied to a printing device, the cartridge comprising: a liquid chamber formed with an inner wall of a reservoir main body member and a flexible sheet member attached to the reservoir main body member; a pressure receiving plate provided in the liquid chamber such that the surface thereof contacts the sheet member; a first biasing member biasing the pressure receiving plate in a direction for enlarging an inner space of the liquid chamber; a liquid supply port supplying liquid stored in the liquid chamber to the printing device; an air introducing port introducing outer air to the inside of the liquid chamber; a valve mechanism including a valve body and a second biasing member biasing the valve body in a direction for closing the air introducing port, the valve mechanism adjusting introduction of air to the liquid chamber by opening or closing the air introducing port; and a liquid detecting section provided inside the liquid chamber to optically detect liquid, wherein, when the cartridge is viewed in a direction perpendicular to a largest outer surface whose area is the largest among a plurality of outer surfaces of the cartridge in a state in which the cartridge is installed in the printing device, the air introducing port is provided in a position closer to an upper end of the largest outer surface relative to a center of the largest outer surface in a vertical direction and in a position closer to one end of a left end and a right end of the largest outer surface relative to a center of the largest outer surface in a horizontal direction, and the liquid detecting section is provided in a position closer to a lower end of the largest outer surface relative to the center of the largest outer surface in the vertical direction and in a position closer to the other end, that is opposite to the one end, of the largest outer surface relative to the center of the largest outer surface in the horizontal direction, and a projecting portion is provided in a position of a third wall facing the back surface of the pressure receiving plate among the inner wall close to the other end, and the projecting section serves as a rotation fulcrum of the pressure receiving plate when the back surface of the pressure receiving plate approaches the third wall, when the cartridge is viewed in the direction perpendicular to the largest outer surface in a state in which the cartridge is installed in the printing device.