Patent ID: 7500740

Claim:
An ink tank containing ink in an ink chamber, for supplying the ink to an ink-jet recording head, said ink tank comprising: an ink detection zone defined in said ink chamber, for an ink run-out sensor to detect as to whether the ink exits or not; an interface provided around said ink detection zone, said interface enhancing resistance to the ink flow in a direction toward said ink detection zone more than in a reversed direction when the ink is consumed so much that its liquid surface goes out of said ink detection zone, a first ink absorbent placed in said ink chamber, said first ink absorbent having a capillary force to absorb and hold the ink in said first ink absorbent, and generate a negative pressure in said ink chamber, and said first ink absorbent including a cutout defining a compartment that includes said ink detection zone, and said cutout providing said interface between said ink detection zone and boundary surfaces of said first ink absorbent which border said cutout.