US Patent 7178908 Buffer tank for ink jet printer

There is disclosed a buffer tank for an ink jet printer, comprising: a main body having a top plate; an air intake through which outside air is taken into the tank; an air outlet passage comprising at least a part extending in the main body downward from the top plate, to flow the air in the tank out into an ink cartridge; and an ink inlet passage comprising at least a part extending in the main body downward from the top plate, to draw the ink in the cartridge into the tank. Each of the air outlet and ink inlet passages comprises a hollow needle disposed at the top plate and vertically extends, and at least one of the air outlet and ink inlet passages comprises a hollow tubular member extending downward from the top plate, whose inner space is in communication with an inner space of the corresponding needle.