Liquid accommodating container providing negative pressure, manufacturing method for the same, ink jet cartridge having the container and ink jet recording head as a unit, and ink jet recording apparatus

A manufacturing method for a liquid container, said method comprising:

• providing the liquid container, comprising:
• a substantially polygonal outer wall provided with an air vent portion and having a corner formed by three surfaces of the outer wall;
• an inner wall having outer surfaces equivalent or similar to inside surfaces of said outer wall and a corner corresponding to the corner of said outer wall, said inner wall defining a liquid accommodating portion for containing liquid therein, said inner wall further having a liquid supply portion for supplying the liquid out of said liquid accommodating portion;
• wherein said inner wall has a thickness which decreases from a central portion of surfaces thereof to the corner, and said outer wall and said inner wall are separable from each other;
• said manufacturing method further comprising:
• reducing pressure of the liquid accommodating portion to separate the inner wall and the outer wall from each other;
• and
• supplying the liquid into the liquid accommodating portion.

A manufacturing method for a liquid container capable of providing a negative pressure, wherein said liquid container includes:

• an outer wall;
• and
• an inner wall having an outer surface equivalent to an inside surface of the outer wall and having a liquid accommodating portion capable of containing liquid therein, and a liquid supply portion for supplying the liquid out of the accommodating portion;
• wherein said liquid container has a polygonal cross-section having sides and corner portions,
• said method comprising the steps of:
• providing a mold corresponding to an outer shape of the liquid container;
• providing a substantially cylindrical shaped first parison for the outer wall, said first parison having a diameter smaller than that of the mold;
• providing a substantially cylindrical shaped second parison for the inner wall;
• expanding the first and second parisons by injecting air so that a thickness of the inner wall in a corner portion is smaller than that in a central portion of each side, so that the first parison extends along the mold, so that the inner wall and the outer wall are separable from each other except in at least one portion where the inner wall and the outer wall are integrated, and so that a space defined by the inner wall and a space defined by the outer wall are similar in configuration to each other;
• and
• forming a liquid supply portion in said one portion where said inner wall and said outer wall are integral.

A manufacturing method for a liquid container, wherein said liquid container includes:

• an outer wall;
• an inner wall having an outer surface equivalent to the inside surface of the outer wall and having a liquid accommodating portion capable of containing liquid to be supplied to a liquid ejection head, and a liquid supply portion of supplying the liquid out of the liquid accommodating portion;
• wherein said liquid container has a polygonal cross-section having sides and corner portions,
• said method comprising the steps of:
• providing a mold corresponding to an outer shape of the liquid container;
• providing a substantially cylindrical shaped first parison for the outer wall, said first parison having a diameter smaller than that of the mold;
• providing a substantially cylindrical shaped second parison for the inner wall;
• expanding the first and second parisons by injecting air so that a thickness of the inner wall in a corner portion is smaller than that in a central portion of each side, so that the first parison extends along the mold, so that the inner wall and the outer wall are separable from each other, and a space defined by the inner wall and a space defined by the outer wall are similar in configuration to each other;
• forming a liquid supply portion;
• and
• connecting a valve to the inner wall constituting the liquid supply port.