Patent ID: 7954662

Claim:
A liquid storage container comprising: a flexible sheet and a wall forming a liquid storage space; a supply port supplying liquid in the liquid storage space to the outside; a protection member having substantially the maximum superficies of outer frames, placed outside of the flexible sheet; a plane member having an opening, the plane member being located inside the liquid storage space so as to be opposing to the protection member with the flexible sheet therebetween; and a conic coil spring generating force for pushing the flexible sheet to the protection member, with the plane member therebetween, so as to generate negative pressure to a liquid in the liquid storage space, wherein the opening is defined in the plane member so as to include a position facing a position that is deformable to the utmost of the protection member by an external pressure, wherein a smaller diameter side of the conic coil spring is coupled to the inside of the opening, and a diameter of the smaller diameter side in the coupled state is substantially the same as a diameter of the opening, and wherein a bigger diameter side of the conic coil spring is in contact with the wall, and the flexible sheet is in contact with the plane member so as to cover the opening on the plane member.