Liquid ejection apparatus and image forming apparatus comprising liquid ejection apparatus

Abstract

The liquid ejection apparatus includes: a liquid ejection head which comprises nozzles including at least one suctioned nozzle and at least one non-suctioned nozzle and ejecting liquid, pressure chambers supplying the nozzles with the liquid, and a common liquid chamber supplying the pressure chambers with the liquid; and an individual suctioning unit which suctions the liquid in the at least one suctioned nozzle, wherein when the individual suctioning unit suctions the liquid in the at least one suctioned nozzle, a following inequality is satisfied: P0−ΔPin

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The nature of this invention, as well as other objects and benefits thereof, will be explained in the following with reference to the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures and wherein:

FIG. 1 is a general schematic drawing of an image forming apparatus according to an embodiment of the present invention;

FIG. 2 is a principal plan diagram of the peripheral area of a print unit in the image forming apparatus shown in FIG. 1;

FIGS. 3A to 3C are plan view perspective diagrams showing examples of the composition of a liquid ejection head;

FIG. 4 is a cross-sectional diagram of a liquid ejection head;

FIG. 5 is a cross-sectional diagram of a liquid ejection head for illustrating an embodiment of the present invention;

FIGS. 6A and 6B are cross-sectional diagrams of the vicinity of a nozzle;

FIG. 7 is a perspective diagram of a liquid ejection apparatus according to a first embodiment of the present invention;

FIGS. 8A to 8C are general schematic diagrams showing a cap member according to the first embodiment of the present invention;

FIG. 9 is an acoustic circuit diagram of a liquid ejection apparatus;

FIG. 10 is an acoustic circuit diagram of an ejector section;

FIG. 11 is a diagram of pressure relationships;

FIG. 12 is a comparative diagram for comparing flow channel resistances in a liquid ejection apparatus;

FIG. 13 is a pressure distribution diagram;

FIG. 14 is a principal block diagram showing the system configuration of an image forming apparatus according to an embodiment of the present invention;

FIG. 15 is a perspective diagram of a liquid ejection apparatus according to a second embodiment of the present invention;

FIG. 16 is a general schematic drawing of a cap member according to a second embodiment of the present invention;

FIG. 17 is a cross-sectional diagram of a liquid ejection head according to a third embodiment of the present invention;

FIG. 18 is a diagram of pressure relationships according to the third embodiment of the present invention;

FIG. 19 is a pressure distribution diagram for explaining a fourth embodiment;

FIG. 20 is a perspective diagram of a liquid ejection apparatus according to a fourth embodiment of the present invention;

FIG. 21 is a pressure distribution diagram according to the fourth embodiment of the present invention;

FIG. 22 is a diagram of pressure relationships according to the fourth embodiment of the present invention;

FIG. 23 is a perspective diagram of a further liquid ejection apparatus according to the fourth embodiment of the present invention;

FIG. 24 is a perspective diagram of a liquid ejection apparatus according to a fifth embodiment of the present invention;

FIG. 25 is a perspective diagram of a liquid ejection apparatus according to a sixth embodiment of the present invention;

FIG. 26 is a perspective diagram of a further liquid ejection apparatus according to a sixth embodiment of the present invention;

FIG. 27 is a perspective diagram of a liquid ejection apparatus according to a seventh embodiment of the present invention;

FIG. 28 is a perspective diagram of a further liquid ejection apparatus according to the seventh embodiment of the present invention; and

FIG. 29 is a diagram of pressure relationships according to an eighth embodiment of the present invention.

Claims

1. A liquid ejection apparatus comprising: a liquid ejection head which comprises nozzles including at least one suctioned nozzle and at least one non-suctioned nozzle and ejecting liquid, pressure chambers supplying the nozzles with the liquid, and a common liquid chamber supplying the pressure chambers with the liquid; andan individual suctioning unit which suctions the liquid in the at least one suctioned nozzle,wherein when the individual suctioning unit suctions the liquid in the at least one suctioned nozzle, a following inequality is satisfied: P0−ΔPin<Pn,

2. A liquid ejection apparatus comprising: a liquid ejection head which comprises nozzles including at least one suctioned nozzle and at least one non-suctioned nozzle and ejecting liquid, pressure chambers supplying the nozzles with the liquid, and a common liquid chamber supplying the pressure chambers with the liquid; andan individual suctioning unit which suctions the liquid in the at least one suctioned nozzle,wherein when the individual suctioning unit suctions the liquid in the at least one suctioned nozzle, a following inequality is satisfied: P0−ΔPin<Pn<P0+ΔPout,

3. The liquid ejection apparatus as defined in claim 1, wherein when the individual suctioning unit suctions the liquid in the at least one suctioned nozzle, a following inequality is further satisfied: P0+ΔPout<Pn,

4. The liquid ejection apparatus as defined in claim 1, further comprising filters each of which includes holes having a diameter smaller than a diameter of the nozzles, and which are disposed at positions between the common liquid chamber and the pressure chambers, positions in the pressure chambers, or positions between the pressure chambers and the nozzles.

5. The liquid ejection apparatus as defined in claim 2, further comprising filters each of which includes holes having a diameter smaller than a diameter of the nozzles, and which are disposed at positions between the common liquid chamber and the pressure chambers, positions in the pressure chambers, or positions between the pressure chambers and the nozzles.

6. The liquid ejection apparatus as defined in claim 1, wherein the liquid in the common liquid chamber is pressurized when the individual suctioning unit suctions the liquid in the at least one suctioned nozzle.

7. The liquid ejection apparatus as defined in claim 2, wherein the liquid in the common liquid chamber is pressurized when the individual suctioning unit suctions the liquid in the at least one suctioned nozzle.

8. The liquid ejection apparatus as defined in claim 1, further comprising: an ink tank which supplies the common liquid chamber with the liquid;an ink supply flow channel which connects the ink tank with the common liquid chamber; anda flow channel adjusting mechanism which is provided in the ink supply flow channel and adjusts a flow channel resistance to a flow of the liquid in the ink supply flow channel so as to be substantially inversely proportional to number of the at least one suctioned nozzle.

9. The liquid ejection apparatus as defined in claim 2, further comprising: an ink tank which supplies the common liquid chamber with the liquid;an ink supply flow channel which connects the ink tank with the common liquid chamber; anda flow channel adjusting mechanism which is provided in the ink supply flow channel and adjusts a flow channel resistance to the liquid in the ink supply flow channel so as to be substantially inversely proportional to number of the at least one suctioned nozzle.

10. The liquid ejection apparatus as defined in claim 1, wherein when the individual suctioning unit suctions the liquid in the at least one suctioned nozzle, the liquid ejection head is tilted from a horizontal position in such a manner that one end of the liquid ejection head to which an ink supply flow channel supplying the common liquid chamber with the liquid is connected is situated higher than another end of the liquid ejection head.

11. The liquid ejection apparatus as defined in claim 2, wherein when the individual suctioning unit suctions the liquid in the at least one suctioned nozzle, the liquid ejection head is tilted from a horizontal position in such a manner that one end of the liquid ejection head to which an ink supply flow channel supplying the common liquid chamber with the liquid is connected is situated higher than another end of the liquid ejection head.

12. An image forming apparatus comprising the liquid ejection apparatus as defined in claim 1.

13. An image forming apparatus comprising the liquid ejection apparatus as defined in claim 2.