PURPOSE: To prevent the leakage of ink from the tip of the nozzle of a head chip when an ink tank is separated from a head cartridge by reducing the pressure in a manifold when the ink tank is separated from a tank holder.

CONSTITUTION: A manifold contracting member 36 is arranged so as to press the manifold 19 arranged in a manifoid contracting member insertion port 12a when an ink tank T is mounted on a head cartridge H to reduce the volume of the manifold 19. That is, a negative pressure generating means is constituted of the manifold 19 variable in its internal volume and the manifold contracting member 36 provided on the side of the ink tank T and deforming the manifold 19 so as to reduce the internal volume thereof when the ink tank T is mounted on a tank holder 11.