Patent ID: 7434920

Claim:
A liquid container comprising: a negative pressure producing member accommodating chamber accommodating a negative pressure producing member for absorbing and retaining the liquid, said negative pressure producing member accommodating chamber having a supply port for supplying the liquid to a liquid ejection recording head and an air vent for fluid communication with ambient air, wherein said negative pressure producing member covers an entirety of said supply port; a liquid containing chamber for containing the liquid, said liquid containing chamber being in fluid communication with said negative pressure producing member accommodating chamber through a communicating portion and being substantially sealed except for said communicating portion; and a partition wall for partitioning said liquid container into said negative pressure producing member accommodating chamber and said liquid containing chamber except for said communicating portion; wherein liquid is supplied to said liquid jet recording head through said supply port in an orientation where said supply port faces downward with respect to a direction of gravity when said liquid container is in an in-use orientation, wherein said negative pressure producing member is provided with a recess at a position corresponding to said communicating portion, the recess forming a space; and wherein a ceiling portion of the space provided by said recess functions as a gas introduction surface which is substantially horizontal in said in-use orientation, and wherein said ceiling portion extends horizontally from said communicating portion for a horizontal distance in a direction away from said supply port such that said gas introduction surface is wide.