Patent ID: 8205974

Claim:
An ink tank detachably mounted on a print head ejecting ink, comprising: an ink storage portion for storing the ink; negative-pressure generating member provided in the ink storage portion for adjusting a negative pressure in the ink storage portion; and an ink supply portion connected to a connecting portion of the print head for supplying the ink to the print head and provided with an extendable ink guide member, the ink guide member comprising a compressed portion connected to the connecting portion when the ink guide member is connected to the connecting portion, and a non-compressed portion which is not connected to the connecting portion, wherein when the connecting portion and the ink guide member are connected, meniscus holding forces of the respective compressed and non-compressed portions of the ink guide member satisfy relationships that an initial negative pressure in the ink storage portion is smaller than the meniscus holding force of the non-compressed portion, the meniscus holding force of the compressed portion is smaller than a meniscus holding force of the connecting portion of the print head, and the meniscus holding force of the non-compressed portion is smaller than the meniscus holding force of the compressed portion, wherein the meniscus holding force of the non-compressed portion is smaller than a negative pressure in a boundary area between an adjustable region in which the negative-pressure generating member adjusts the negative pressure in the ink storage portion, and a region in which a negative pressure is higher than that in the adjustable region.