Abstract: In an ink tank, there are provided a main ink chamber containing a capillary vessel member, and an intermediate ink chamber. When the ink is consumed, the ink held by capillary force of a capillary vessel member is supplied via a communication port from a joint port. The same amount of air as the amount of the consumed ink is conducted from the atmospheric communication port into the main ink chamber. The conducted air is supplied via a groove formed in a lid to an upper surface of the capillary vessel member. As a result, the air is entered into the capillary vessel member under better condition. In a plane portion of the lid, the ink is in contact with only the capillary vessel member, and the ink remaining this portion is reduced. Thus, the ink using efficiency is increased.

Abstract: An elastic jointing member 22 with an umbrella-like portion with an opening and a flat part is provided in a jointing portion between a recording head 21 and an ink tank 1. When the ink tank 1 is attached to the recording head 21, the umbrella-like portion of the elastic jointing member 22 is pressed against the ink tank and elastically deformed inward. As a result, an ink passage is formed which is airtightly sealed. In the process of pressing the umbrella-like portion against the ink tank, the umbrella-like portion comes in contact with the flat part, to thereby prevent air from staying in the ink passage. Protrusions or grooves may be provided between the umbrella-like portion and the flat part. With the protrusions or the groove, the umbrella-like portion is not glued to the flat part.

Abstract: In an ink tank, there are provided a main ink chamber containing a capillary vessel member, and an intermediate ink chamber. When the ink is consumed, the ink held by capillary force of a capillary vessel member is supplied via a communication port from a joint port. The same amount of air as the amount of the consumed ink is conducted from the atmospheric communication port into the main ink chamber. The conducted ink is supplied via a groove formed in a lid to an upper surface of the capillary vessel member. As a result, the air is entered into the capillary vessel member under better condition. In a plane portion of the lid, the ink is in contact with only the capillary vessel member, and the ink remaining this portion is reduced. Thus, the ink using efficiency is increased.

Abstract: An ink jet printer which causes ink to fly to a recording medium to form an image, comprising: plural nozzles functioning as ink ejection ports; plural individual flow paths which are disposed with respectively corresponding to the nozzles, the individual flow paths respectively having driving elements which eject internal ink through the nozzles; a common liquid chamber which communicates with the individual flow paths, the common liquid chamber having an opening portion through which ink is supplied into the chamber; an ink supply path which has a sectional area smaller than a sectional area of the opening portion of the common liquid chamber, the ink supply path being connected to the opening portion to guide ink to the common liquid chamber; and an ink supply source for supplying ink through the ink supply path.

Abstract: An ink supply passage 16 has a large cross-sectional area and ink tanks 6 are connected to the top of the ink supply passage 16. An ink supply passage 17 is a flow passage shaped like a semicylinder and has a cross-sectional area equal to or smaller than the cross-sectional area of the ink supply passage 16. Even if bubbles are mixed into the ink supply passage 17, they adhere to the upper portion of the flow passage 17 and do not flow into lower corners, so that a flow passage can be provided and the ink flow is not hindered. Since an ink supply passage 19 connected to a head chip 4 has a small diameter, bubbles mixed into the ink supply passage 19 can be removed by maintenance for sucking ink forcibly. Bubbles mixed upstream are not transported to the ink supply passage 19 because of the flow rate difference caused by the cross-sectional area difference.

Abstract: A main ink chamber with a through-hole contains a capillary member. An intermediate ink chamber is provided on the side wall of the main ink chamber. A path communicatively interconnects the main ink chamber and the intermediate ink chamber. A second meniscus forming member is disposed in a joint port, to thereby prevent ink leakage. In a print mode, ink flows from the main ink chamber to the joint port, through a meniscus forming member that is disposed in the through-hole. Air bubbles mingled into the ink move along the slanting upper wall of the path by their buoyant force, and are accumulatively stored in the upper part of the intermediate ink chamber. When ink is reduced to zero in the main ink chamber, air bubbles are introduced into the intermediate ink chamber through the meniscus forming member. As a result, the liquid level of the intermediate ink chamber is quickly reduced, thereby indicating a state that ink is used up.

Abstract: Ink-jet recording ink improved in releasability of bubbles and the like. The ink comprises water, a colorant and a water-soluble organic solvent. The surface tension of the ink at 20.degree. C. is higher than the surface tension of a composition which comprises the components for the ink except the colorant. Ink-jet recording is effected by making use of the ink and, for example, a heating system.

Abstract: Considering the differential pressure .DELTA.P between pressures applied to both faces of a meniscus formation member, the differential pressure .DELTA.P becomes the maximum when an ink supply unit is left standing with the meniscus formation member placed upward. At this time, water head PH of ink attempting to fall due to gravity is applied to the inner face of the meniscus formation member in the same direction as negative pressure PR of a capillary member. Thus, the differential pressure .DELTA.P becomes .DELTA.P=PR+PH. The bubble point pressure PB of the meniscus formation member is set greater than the maximum value of the differential pressure, .DELTA.P=PR+PH, whereby air does not enter an ink tank through the meniscus formation member.