Claims
- 1. An ink jet printer system having a multiple-nozzle print head coupled to an ink source for ejecting ink through a plurality of nozzles as the ink moves in a direction of ink flow between a supply source and the plurality of nozzles, comprising:
- an ink supply manifold having a first end and a second end, the first end being coupled to the ink source and having a greater cross-sectional area than at any other point in the ink supply manifold so that it is tapered from greater cross-sectional area to lesser cross-sectional area in the direction of ink flow, the ink supply manifold further having multiple ink pressure chambers positioned between multiple ink inlets of substantially equal lengths and equal cross-sectional areas and multiple passages of substantially equal length and equal cross-sectional areas to thereby create equal ink fluid impedances between the multiple ink inlets;
- multiple nozzles coupled to the ink supply manifold by separate ink channels through openings distributed between the first and second ends;
- transducers connected to the ink supply manifold and coupled to the ink pressure chambers, the transducers being drivern with substantially similar waveforms to draw ink from the ink source through the manifold and inlet channels and to expel ink from each pressure chamber through a corresponding associated passage and nozzle in a manner exhibiting substantially identical jetting characteristics;
- and a purging mechanism connectable to the print head causing ink to flow by application of a vacuum at the same ink flow rate into the first end of the ink supply manifold, through the ink supply manifold at a flow rate, and from the ink manifold through the ink channels to the nozzles;
- whereby a tapered difference in cross-sectional area in the ink supply manifold at the first end from that at any other point toward the second end is such that the taper is from greater cross-sectional area to lesser cross-sectional area in the direction of ink flow and causes the ink flow rate in the ink supply manifold to create a resultant force that acts on bubbles that is the result from the effort of gravitational force, buoyant force and an ink flow rate induced force, the ink flow rate being everywhere sufficient so that contaminants or bubbles are effectively purged from the ink supply manifold by causing the bubbles to move in the direction of ink flow and direction of the resultant force.
- 2. The apparatus of claim 1 in which the purging mechanism causes ink to flow in a direction from the nozzles toward the source of ink.
- 3. The apparatus of claim 1 in which the ink supply manifold is oriented elevationally above the nozzles and substantially only bubbles are purged from the print head.
- 4. A multiple-nozzle ink jet print head purgeable of contaminants or bubbles for receiving ink from a source of ink and for ejecting ink from a plurality of nozzles, the ink moving in a direction of ink flow between the source of ink and the nozzles, comprising:
- a body containing an ink manifold coupled to the source of ink, the ink manifold having a continuously decreasingly tapered cross-sectional area in the direction of ink flow between first and second ends thereof; the body further containing multiple ink pressure chambers of substantially circular cross-sectional area positioned between diametrically opposed ink inlet channels of substantially equal lengths and ink passages of substantially equal lengths, the ink inlet channels being of substantially equal lengths and cross-sectional areas thereby having equal ink fluid impedances, the ink inlet channels further being coupled to the ink manifold at points distributed between the first and second ends to deliver ink through different ones of the passages and ink pressure chambers to a nozzle associated with each ink pressure chamber; and the body having multiple purging channels, each disposed between an associated passage and nozzle and coupled to a common ink outlet;
- transducers mounted to the body and coupled to the ink pressure chambers, the transducers being driven with substantially similar waveforms to draw ink from the source of ink through the manifold and inlet channels and to expel ink from each pressure chamber through a corresponding associated passage and nozzle in a manner exhibiting substantially identical jetting characteristics thereby creating an ink flow rate within the decreasingly tapered cross-sectional area of the manifold that includes a resultant force that acts on bubbles within the manifold which is the result of the coactive effect of gravitational force, buoyant force and an ink flow rate induced force to force bubbles from the manifold into the ink pressure chambers;
- acoustic drivers connected to the transducers to provide the waveforms to drive to transducers; and
- a purging mechanism connectable to the print head causing by the application of a vacuum ink to flow through the print head, whereby the manifold, pressure chambers, and purging channels are sized for ink volume and flow rate and positioned to cause the ink flow to remove the contaminants or bubbles in the print head.
- 5. The apparatus of claim 4 in which the purging mechanism causes ink to flow in a direction from the source of ink toward the ink outlet.
- 6. The apparatus of claim 4 in which the ink manifold is oriented elevationally above the nozzles and substantially only bubbles are purged from the print head.
- 7. A method for purging contaminants or bubbles from a multiple-orifice ink jet head from which ink is ejected through a plurality of orifices, comprising the steps of:
- providing an ink supply manifold having a volume and first and second ends, the ink supply manifold being in fluid communication in a direction of ink flow between the ink supply manifold and the orifices with multiple ink supply channels of substantially equal lengths and cross-sectional areas to thereby create equal ink fluid impedances between the multiple ink supply channels, the ink supply channels being distributed at locations between the first and second ends, the ink supply manifold having at least a portion of the volume in the direction of ink flow tapered to define a first cross-sectional area and a smaller second cross-sectional area between the first and second ends such that the smaller cross-sectional area is located adjacent to the second end;
- causing ink to flow at a flow rate through an ink inlet adjacent to the first end of the ink supply manifold by the action of a plurality of transducers connected to the manifold, the transducers being driven with substantially similar waveforms so that ink expelled from the plurality of orifices exhibit substantially identical jetting characteristics; and
- drawing ink from the ink supply channels at the same flow rate by the application of a vacuum,
- whereby the tapered volume portion in the direction of ink flow maintains everywhere within the ink supply manifold a flow rate that includes a resultant force that acts on bubbles within the manifold which is the result of the effect of gravitational force, buoyant force and an ink flow rate induced force to direct the bubbles out of the manifold in the direction of ink flow, the flow rate thereby being sufficient to purge the ink supply manifold of contaminants or bubbles carried by the ink as the ink is drawn from the ink supply channels.
- 8. The method of claim 7 in which the ink flow in the ink supply manifold is in a direction from the ink inlet toward the ink supply channels.
- 9. The method of claim 7 in which the ink supply manifold is oriented elevationally above the ink supply channels and substantially only bubbles are purged from the multiple-orifice ink jet head.
Parent Case Info
This is a continuation of application Ser. No. 07/894,316 filed Jun. 4, 1992 now abandoned.
US Referenced Citations (14)
Foreign Referenced Citations (1)
Number |
Date |
Country |
55-067478 |
May 1980 |
JPX |
Continuations (1)
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Number |
Date |
Country |
Parent |
894316 |
Jun 1992 |
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