Bubble valving for ink-jet printheads
AssigneeHewlett-Packard Company
InventorsTimothy L. Weber, David J. Waller, Kenneth E. Trueba, David Thomas
Life of this patent
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Abstract
The configuration of an ink inlet through which flows ink into a chamber for expulsion from the chamber by a thermal process is such that a vapor bubble generated by the thermal process to eject ink from the chamber expands to simultaneously occlude the inlet, thereby to separate the ink within the chamber from ink within a channel that is in fluid communication with the inlet. The separation eliminates a liquid path between the chamber and the channel so that substantially no ink is blown back into the channel as the bubble expands, thereby improving the thermal efficiency of the process.
Claims14
An ink-jet printhead for ejecting ink droplets, comprising:
- a chamber member having a chamber defined therein, the chamber having an orifice through which ink is ejected from the chamber;
- a heating member positioned within the chamber for selectively generating a vapor bubble within the chamber;
- an ink inlet through which ink flows to the chamber, the ink inlet being arranged to be occluded by the vapor bubble;
- wherein the inlet defines an inlet flow area across which ink flows into the chamber, and wherein the inlet flow area is contiguous with the chamber and wherein the inlet flow area provides an areal restriction to ink flow into the chamber;
- and
- wherein the heating member has a length and the inlet is spaced from the heating member by a distance which is no more than about 25% of the heating member length.
An ink-jet printhead for ejecting ink droplets, comprising:
- a chamber member having a chamber defined therein, the chamber having an orifice through which ink droplets are ejected from the chamber substantially parallel to a central axis of the orifice, the chamber member also having an inlet through which ink flows into the chamber along a flow path;
- wherein
- an angle is defined between the flow path along which the ink flows and the central axis of the orifice;
- the angle between the central axis and the flow path being less than about 90 degrees so that the flow of ink from the inlet into the chamber is generally directed toward the orifice;
- wherein
- a heating member is positioned within the chamber for selectively generating a vapor bubble within the chamber;
- and
- wherein
- the heating member has a length and the inlet is spaced from the heating member by a distance which is no more than about 25% of the heating member length.
A method of ejecting ink droplets from a printhead, wherein the printhead includes a heating member disposed within a chamber defined in the printhead, the heating member having a length, the chamber containing ink and having an orifice through which ink droplets are ejected from the chamber along a central axis, and an inlet through which ink flows into the chamber, and wherein a vapor bubble is created in the ink in the chamber when the heating member is heated by an amount sufficient to eject an ink droplet from the chamber, the method comprising the steps of:
- configuring the chamber so that the inlet is occluded by the bubble;
- locating the inlet adjacent to the heating member so that the bubble protrudes through the inlet to occlude the inlet;
- and
- wherein the heating member is arranged in the chamber whereby the central axis of the chamber is generally normal to the length of the heating member.
A method of controlling the ejection of ink droplets from a chamber of an ink jet printhead, comprising the steps of:
- providing the chamber with an orifice through which an ink droplet may be elected from the chamber;
- providing an inlet through which ink flows into the chamber;
- expanding a vapor bubble in the chamber by an amount sufficient to eject an ink droplet from the chamber and substantially simultaneously to occlude the inlet with the bubble.
Dependencies are inferred from the claim text.