INKJET PRINTHEAD AND METHOD OF REMOVING BUBBLES IN THE SAME

Abstract

An inkjet printhead includes an ink flow channel including a pressure chamber, a nozzle to communicate with the pressure chamber, an actuator to provide a driving force to eject ink from the pressure chamber, and a plurality of electrodes, a lower voltage is applied to an electrode closer to the nozzle as compared to an electrode farther from the nozzle to form a non-uniform electric field in the ink flow channel, and a method of removing bubbles in the inkjet printhead.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a plan view illustrating an inkjet printhead, according to an embodiment of the present general inventive concept;

FIG. 2 is a cross-sectional view illustrating the inkjet printhead of FIG. 1;

FIG. 3 is a sectional view taken along line A-A of FIG. 2;

FIG. 4 is a view illustrating a movement of bubbles by a non-uniform electric field formed by a plurality of electrodes in the inkjet printhead of FIG. 1, according to an embodiment of the present general inventive concept; and

FIG. 5 is a view illustrating a sucking of ink to remove bubbles in the inkjet printhead of FIG. 1, according to an embodiment of the present general inventive concept.

Claims

1. An inkjet printhead, comprising: an ink flow channel including a pressure chamber to contain ink;a nozzle to communicate with the pressure chamber;an actuator to provide a driving force to eject the ink from the pressure chamber; anda plurality of electrodes to receive voltages to form a non-uniform electric field in the ink flow channel such that an electrode closer to the nozzle receives a lower voltage relative to an electrode farther from the nozzle.

2. The inkjet printhead of claim 1, wherein the voltages are variable-frequency, traveling-pulse voltages.

3. The inkjet printhead of claim 1, wherein the plurality of electrodes is disposed on walls forming the ink flow channel.

4. A method of bubbles removing in an inkjet printhead including an ink flow channel having a pressure chamber to contain ink, a nozzle to communicate with the pressure chamber, an actuator to provide an ink ejecting force to the pressure chamber, and a plurality of electrodes disposed in the ink flow channel, the method comprising: applying voltages to the plurality of electrodes such that a lower voltage is applied to an electrode closer to the nozzle relative to an electrode farther from the nozzle;moving bubbles to the nozzle by a non-uniform electric field formed by the plurality of electrodes and dielectrophoresis generated by dipole moments of the bubbles; anddischarging the bubbles through the nozzle.

5. The method of claim 4, wherein the discharging of the bubbles comprises: discharging the bubbles together with the ink through the nozzle.

6. The method of claim 4, wherein the discharging of the bubbles comprises: applying a negative pressure to the nozzle to suck the bubbles out of the pressure chamber through the nozzle.

7. The method of claim 4, wherein the voltages applied to the plurality of electrodes are variable-frequency, traveling-pulse voltages to accelerate the bubbles.

8. A printhead, comprising: a chamber layer comprising an ink chamber to contain ink;a nozzle layer disposed on the chamber layer and comprising a nozzle in communication with the ink chamber to eject the ink from the ink chamber;an actuator to provide a driving force to eject the ink from the ink chamber through the nozzle; anda plurality of electrodes to move bubbles in the ink contained in the ink chamber to the nozzle.

9. The printhead of claim 8, wherein the plurality of electrodes move the bubbles in the ink to the nozzle using dielectrophoresis.

10. The printhead of claim 8, wherein the plurality of electrodes generates a non-uniform electric field in the ink chamber to dielectrically polarize the bubbles and applies a force to move the polarized bubbles towards the nozzle.

11. The printhead of claim 8, wherein the plurality of electrodes is disposed on a wall of the ink chamber.

12. The printhead of claim 8, wherein shapes of at least a portion of the plurality of electrodes are non-uniform shapes.

13. The printhead of claim 12, wherein the non-uniform shapes include at least one of a flat panel shape extending in a width direction of the ink chamber, and a flat panel shape including branches protruding in a length direction of the ink chamber.

14. The printhead of claim 8, further comprising: a voltage applying unit to apply voltages to the plurality of electrodes.

15. The printhead of claim 14, wherein the voltage applying unit applies a first voltage to a portion of the plurality of electrodes disposed closer to the nozzle, and applies a second voltage to a portion of the plurality of electrodes disposed farther from the nozzle.

16. The printhead of claim 15, wherein the first voltage is lower than the second voltage.

17. The printhead of claim 14, wherein the voltages applied by the voltage applying unit are variable-frequency traveling pulse voltages to accelerate the movement of the bubbles towards the nozzle.

18. The printhead of claim 8, wherein the actuator is selected from a thermal actuator and a piezoelectric actuator.

19. The printhead of claim 8, wherein the chamber layer further comprises: a manifold to supply ink to the ink chamber; anda restrictor to restrict a back flow of ink from the ink chamber to the manifold.

20. A method of removing bubbles from a printhead including an ink chamber to contain ink and a nozzle in communication with the pressure chamber to eject the ink, the method comprising: generating a non-uniform electric field in the ink chamber to dielectrically polarize bubbles in the ink and to apply a force to move the polarized bubbles towards the nozzle; andejecting the bubbles from the ink chamber through the nozzle by applying a negative pressure to the nozzle.

21. The method of claim 20, wherein the generation of the non-uniform electric field comprises: applying voltages to electrodes disposed in the ink chamber.

22. The method of claim 21, wherein shapes of at least a portion of the electrodes are non-uniform shapes.

23. The method of claim 21, wherein the applying of the voltages to the electrodes comprises: applying a lower voltage to a portion of the electrodes closer to the nozzle and applying a higher voltage a portion of the electrodes farther from the nozzle to move the polarized bubbles towards the nozzle.

24. A method of removing bubbles from a printhead, comprising: gathering bubbles around a nozzle of the printhead by dielectrophoresis using a plurality of electrodes; anddischarging the bubbles gathered around the nozzle through the nozzle by applying a force at the nozzle.