Patent ID: 7465044

Claim:
An ink jet recording apparatus comprising: a recording part configured to record and including a discharge head; a mounting part capable of mounting a main tank; and a sub tank adapted to store a liquid supplied from the main tank for supply to the discharge head, the sub tank comprising: two flow paths communicating with the main tank; an atmosphere communicating part; and a liquid exit part communicating with the discharge head, wherein one of the two flow paths has a flow path resistance lower than that of the other flow path, wherein the flow path having the lower flow path resistance includes an air introducing path introducing air into the main tank, and wherein the other flow path includes a liquid supply path facilitating supplying the liquid from the main tank to the sub tank, wherein the air introducing path has a cross-sectional area, in a direction perpendicular to the air flow direction therein, larger than a cross-sectional area of the liquid supply path in a direction perpendicular to the liquid flow direction, wherein the cross-sectional area of the air introducing path varies along the air flow direction, wherein, within the air introducing path, a flow path portion has an enlarged cross-sectional area sized so as to inhibit a meniscus formation by the liquid, and wherein a water head difference (H) in the vertical direction in the flow path portion of the enlarged cross-sectional area, a meniscus force (M) by the cross-sectional area in a flow path portion of a smaller cross-sectional area, and an entire flow path resistance (R) of the air introducing path and a portion of the ink supply path having a smaller cross-sectional area, satisfy a following relationship: H>M+R.