Liquid discharge device

Abstract

To provide a liquid discharge device that can suppress a nozzle from discharging liquid poorly due to air bubbles.SOLUTION: A liquid discharge device 10 is provided with: a plurality of first pressure chambers 33 extending in a first extending direction; a plurality of second pressure chambers 35 extending in the first extending direction; a communication path 34 extending in a second extending direction that is different from the first extending direction, which is connected to the first pressure chambers 33 and the second pressure chambers 35; a nozzle 21, connected to the communication path 34, which discharges liquid; a supply manifold 24 communicating with the plurality of first pressure chambers 33, which supplies liquid; and a recovery manifold 25 communicating with the plurality of second pressure chambers 35, which recovers liquid. The communication path has a first end 34a and a second end 34b which are both ends in the second extending direction, where the first end is connected to the first pressure chambers and the second end is connected to the second pressure chambers.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection device that ejects liquid. [Background technology]

[0002] A known example of a conventional liquid ejection device is the liquid ejection device disclosed in Patent Document 1. This liquid ejection device includes individual flow paths, a supply manifold that supplies liquid to the individual flow paths, and a return manifold through which liquid flowing out of the individual flow paths flows. In the individual flow paths, nozzles are connected to a communication flow path, and the communication flow path is connected to two descender flow paths, each of which is connected to a pressure chamber. Of the two pressure chambers, one pressure chamber is connected to the supply manifold, and the other pressure chamber is connected to the return manifold. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-55492 Summary of the Invention [Problem to be solved by the invention]

[0004] In the liquid ejection device described above, liquid flows from a supply manifold through one pressure chamber, a descender flow path, and a connecting flow path in that order, and is then supplied to a nozzle. A portion of the liquid is ejected from the nozzle, and the remaining liquid that is not ejected flows through the connecting flow path, the other descender flow path, and the pressure chamber in that order, and then flows to the return manifold. However, if air bubbles are present in the liquid between the pressure chamber and the nozzle, for example, the air bubbles may reduce the pressure applied to the pressure chamber, making it impossible to apply the desired pressure to the liquid in the nozzle, or the air bubbles may enter the nozzle, resulting in poor ejection of the liquid from the nozzle.

[0005] In view of the above, an object of the present invention is to provide a liquid ejection device that can prevent defective ejection of liquid from nozzles caused by air bubbles. [Means for solving the problem]

[0006] A liquid ejection device according to the present disclosure comprises a plurality of first pressure chambers extending in a first extension direction, a plurality of second pressure chambers extending in the first extension direction, a communicating passage extending in a second extension direction different from the first extension direction and connected to the first pressure chambers and the second pressure chambers, a nozzle connected to the communicating passage and ejecting liquid, a supply manifold communicating with the plurality of first pressure chambers to supply liquid, and a recovery manifold communicating with the plurality of second pressure chambers to recover liquid, wherein the communicating passage has a first end and a second end which are opposite ends in the second extension direction, the first end being connected to the first pressure chambers and the second end being connected to the second pressure chambers. [Effects of the Invention]

[0007] According to the present disclosure, because the second extension direction of the communicating passage is different from the first extension direction of the first pressure chamber and the second pressure chamber, when liquid flows through the first pressure chamber, the communicating passage, and the second pressure chamber, the flow direction of the liquid changes sequentially from the first extension direction to the second extension direction and back to the first extension direction. This changing liquid flow makes it easier to remove air bubbles adhering to the wall surfaces of the first pressure chamber, the communicating passage, and the second pressure chamber, respectively, making it easier to smoothly discharge the air bubbles from the first pressure chamber, the communicating passage, and the second pressure chamber. Furthermore, because the first pressure chamber and the second pressure chamber are directly connected to the communicating passage, air bubbles are more easily discharged from the first pressure chamber and the second pressure chamber than if there were a descender flow path between the pressure chamber and the nozzle. In this way, because air bubbles are more easily discharged, it is possible to suppress poor discharge of liquid from the nozzle caused by air bubbles. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of a liquid ejection device according to the present disclosure, viewed from above; [Figure 2] FIG. [Figure 3] 3 is a cross-sectional view schematically showing a part of the head when cut along line B in FIG. 2. FIG. [Figure 4] FIG. 3 is an enlarged view of a portion of the flow path body of FIG. 2. [Figure 5] 10 is an enlarged view of a part of a flow path body in a liquid ejection device according to a first modified example. FIG. [Figure 6] 10 is an enlarged view of a part of a flow path body in a liquid ejection device according to a second modification. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Liquid discharge device> 1, a liquid ejection device 10 according to an embodiment of the present disclosure is a device that ejects liquid, and is, for example, a printing device such as an inkjet printer. In the following, a case where a serial head type inkjet printer is used as the liquid ejection device 10 will be described, but the liquid ejection device 10 is not limited to this, and for example, a line head type inkjet printer or the like may also be used as the liquid ejection device 10.

[0010] The liquid ejection device 10 includes a liquid ejection head (hereinafter referred to as a head) 20 that ejects liquid. The head 20 has a plurality of nozzles 21 that eject liquid such as ink. The plurality of nozzles 21 are arranged in a row to form a nozzle row. The plurality of nozzle rows are arranged in a direction that intersects (for example, perpendicular to) the direction in which the plurality of nozzles 21 are arranged. Note that, hereinafter, the direction in which the plurality of nozzles 21 are arranged is referred to as the front-rear direction, the direction in which the plurality of nozzle rows are arranged is referred to as the left-right direction, and a direction that intersects (for example, perpendicular to) these directions is referred to as the up-down direction. However, the directions related to the liquid ejection device 10 are not limited to these.

[0011] Furthermore, the liquid ejection device 10 includes a cartridge 11 that stores liquid. The cartridge 11 is detachably attached to the housing of the liquid ejection device 10. The cartridge 11 supplies liquid to the nozzles 21.

[0012] The liquid ejection device 10 further includes a transport device 13 that transports the ejection receiving medium A, and a moving device 14 that moves the head 20. The transport device 13 has a roller 13a whose axis extends in the left-right direction. The roller 13a rotates about its axis, thereby transporting the ejection receiving medium A in the front-to-rear direction. The moving device 14 also has a guide rail 14a that extends in the left-to-right direction, and an endless belt 14b connected to the head 20. As the endless belt 14b runs, the head 20 is supported by the guide rail 14a and moves in the left-to-right direction. In the printing process of this liquid ejection device 10, the head 20 ejects liquid from the nozzles 21 onto the ejection receiving medium A while moving in the left-to-right direction, and an image is printed on the ejection receiving medium A by transporting the ejection receiving medium A in the front-to-rear direction.

[0013] <head> 2 and 3, the head 20 has a liquid flow path 22 and a chip 23 in which the liquid flow path 22 is formed. The chip 23 has, for example, a plurality of plates stacked in the vertical direction. The plurality of plates includes a nozzle plate 23a, a flow path plate 23b, a vibration plate 23c, a common plate 23d, and a damper plate 23e.

[0014] The liquid flow path 22 is formed in the chip 23 by through holes and depressions formed in each of the multiple plates. The liquid flow path 22 has a space through which the liquid flows and a surface of the chip 23 that defines (forms) that space. The liquid flow path 22 has a plurality of nozzles 21, a plurality of individual paths 30 connected to the plurality of nozzles 21 respectively, and a supply manifold 24 and a recovery manifold 25 connected to the plurality of individual paths 30.

[0015] The nozzle plate 23a is formed with a plurality of nozzles 21. The nozzles 21 extend in the vertical direction, penetrate the nozzle plate 23a, and open to a discharge surface 23a1, which is the lower surface of the nozzle plate 23a. As a result, liquid is discharged from the openings of the nozzles 21.

[0016] The flow path plate 23b is laminated on the nozzle plate 23a. A plurality of individual paths 30 are formed in the flow path plate 23b. An individual path 30 is provided for each nozzle 21, and includes a first connection path 31, a first communication path 32, a first pressure chamber 33, a communication path 34, a second pressure chamber 35, a second communication path 36, and a second connection path 37. These paths penetrate the flow path plate 23b in the vertical direction. The lower openings of the first connection path 31, the first communication path 32, the first pressure chamber 33, the communication path 34, the second pressure chamber 35, the second communication path 36, and the second connection path 37 are covered by the nozzle plate 23a, and their lower ends are formed by the upper surface of the nozzle plate 23a.

[0017] The communication passage 34 is connected to the nozzle 21, the first pressure chamber 33, and the second pressure chamber 35, the first communication passage 32 is connected to the first pressure chamber 33 and the first connection passage 31, and the second communication passage 36 is connected to the second pressure chamber 35 and the second connection passage 37. As a result, in the individual passage 30, the first connection passage 31, the first communication passage 32, the first pressure chamber 33, the communication passage 34, the second pressure chamber 35, the second communication passage 36, and the second connection passage 37 are connected in this order. Details of this individual passage 30 will be described later.

[0018] The vibration plate 23c is stacked on the flow path plate 23b and covers the upper openings of the communication passage 34, the first pressure chamber 33, the second pressure chamber 35, the first communication passage 32, and the second communication passage 36 of the flow path plate 23b. The upper ends of the communication passage 34, the first pressure chamber 33, the second pressure chamber 35, the first communication passage 32, and the second communication passage 36 are formed by the lower surface of the vibration plate 23c. In addition, the first connection passage 31 and the second connection passage 37 penetrate the vibration plate 23c in the vertical direction.

[0019] The vibration plate 23c has piezoelectric elements 27 provided at positions corresponding to the first pressure chamber 33 and the second pressure chamber 35. When the piezoelectric element 27 corresponding to the first pressure chamber 33 and the piezoelectric element 27 corresponding to the second pressure chamber 35 are driven, the vibration plate 23c is deformed and applies an ejection pressure to the liquid in each of the first pressure chamber 33 and the second pressure chamber 35. This ejection pressure is transmitted from the first pressure chamber 33 and the second pressure chamber 35 to the nozzle 21 via the communication passage 34, and the liquid is ejected from the nozzle 21.

[0020] The common plate 23d is stacked on the vibration plate 23c. A supply manifold 24 and a recovery manifold 25 are formed on the common plate 23d. The supply manifold 24 has a main supply channel 24a and multiple supply branch channels 24b and is comb-shaped, with the main supply channel 24a branching off into multiple supply branch channels 24b. The multiple supply branch channels 24b are arranged parallel to one another and spaced apart in the front-to-rear direction. For example, the supply branch channels 24b extend obliquely rearward and leftward from the main supply channel 24a and are formed by recesses recessed downward from the upper surface. Each of the first connection channels 31 of the multiple individual channels 30 penetrates the common plate 23d below the supply branch channel 24b and is connected to the supply branch channel 24b. As a result, the supply branch channels 24b of the supply manifold 24 are connected to the first pressure chambers 33 of the multiple individual channels 30, respectively.

[0021] The main supply channel 24a extends in the direction in which the multiple nozzles 21 are lined up, for example, in the front-to-rear direction, and is connected to the right ends of the multiple branch supply channels 24b. As a result, for example, as the liquid flows forward through the main supply channel 24a, it branches into the multiple branch supply channels 24b connected to the main supply channel 24a. As the liquid flows leftward through the branch supply channel 24b, it branches into the multiple individual channels 30 connected to the branch supply channel 24b. The liquid is then supplied to the nozzles 21 that are connected to the multiple individual channels 30, respectively.

[0022] The recovery manifold 25 has a main recovery channel 25a and multiple recovery branch channels 25b, and is comb-shaped, with the main recovery channel 25a branching into multiple recovery branch channels 25b. The multiple recovery branch channels 25b are arranged parallel to one another and spaced apart in the front-to-rear direction. For example, the recovery branch channels 25b extend diagonally forward and to the right from the main recovery channel 25a and are formed by recesses recessed downward from the top surface. Each of the second connection channels 37 of the multiple individual channels 30 penetrates the common plate 23d below the recovery branch channel 25b and is connected to the recovery branch channel 25b. As a result, the recovery branch channels 25b of the recovery manifold 25 are connected to the second pressure chambers 35 of the multiple individual channels 30, respectively.

[0023] The main recovery channel 25a extends in the direction in which the nozzles 21 are lined up, for example, in the front-to-rear direction, and is connected to the left ends of the respective recovery branch channels 25b. As a result, the liquid is recovered from the respective individual channels 30 into the recovery branch channel 25b and flows to the left through the recovery branch channel 25b. The liquid then merges with the main recovery channel 25a from the respective recovery branch channels 25b and flows forward through the main recovery channel 25a.

[0024] In the left-right direction, a plurality of supply branch paths 24b and a plurality of recovery branch paths 25b are arranged in the front-rear direction between the main supply path 24a and the main recovery path 25a. The supply branch paths 24b and the recovery branch paths 25b are parallel to each other and alternately arranged in the front-rear direction.

[0025] The supply manifold 24 and the recovery manifold 25 are connected to a tank 26. The tank 26 is mounted on the head 20, for example, and connected to the cartridge 11 (FIG. 1) by a pipe or the like, and stores the liquid supplied from the cartridge 11. The tank 26 is connected to a main supply path 24a of the supply manifold 24 by a supply path 26a, and is also connected to the recovery manifold 25 by a recovery path 26b. A supply pump 26a1 is provided in the supply path 26a, and a recovery pump 26b1 is provided in the recovery path 26b.

[0026] The tank 26, supply channel 26a, main supply channel 24a, branch supply channel 24b, first connection channel 31, first communication channel 32, first pressure chamber 33, communication channel 34, second pressure chamber 35, second communication channel 36, second connection channel 37, branch recovery channel 25b, main recovery channel 25a, recovery channel 26b, and tank 26 are connected in this order to form a liquid circulation channel. When supply pump 26a1 and recovery pump 26b1 are driven, the liquid flows through the circulation channel in this order.

[0027] The liquid flows through the tank 26, supply channel 26a, main supply channel 24a, branch supply channel 24b, first connection channel 31, first communication channel 32, first pressure chamber 33, and communication channel 34, and is supplied to the nozzle 21. When the piezoelectric element 27 is driven, a discharge pressure is applied to the liquid in the first pressure chamber 33 and the second pressure chamber 35, and the discharge pressure is transmitted from the first pressure chamber 33 and the second pressure chamber 35 to the communication channel 34 and nozzle 21, causing the liquid to be discharged from the nozzle 21. The liquid that is not discharged from the nozzle 21 passes through the communication channel 34, second pressure chamber 35, second communication channel 36, second connection channel 37, branch recovery channel 25b, main recovery channel 25a, and recovery channel 26b, and is recovered into the tank 26.

[0028] The damper plate 23e is stacked on the common plate 23d. The damper plate 23e has a through-hole formed therein, and a damper 28 is provided to cover the through-hole. The damper 28 is made of a thin metal or inorganic film that is elastic and resistant to organic solvents, and has a thickness of, for example, 10 μm or less. The damper 28 covers the supply branch channel 24b and the recovery branch channel 25b. The damper 28 flexes to absorb pressure applied to the liquid flowing through the supply branch channel 24b and the recovery branch channel 25b.

[0029] <Individual Route> As described above, the individual passage 30 has the first connection passage 31, the first communication passage 32, the first pressure chamber 33, the communication passage 34, the second pressure chamber 35, the second communication passage 36, and the second connection passage 37, which are connected in this order. The nozzle 21 is connected to the communication passage 34. For example, the first pressure chamber 33 and the second pressure chamber 35 have the same shape and size, the first communication passage 32 and the second communication passage 36 have the same shape and size, and the first connection passage 31 and the second connection passage 37 have the same shape and size. Furthermore, when viewed from above, the first communication passage 32 and the first pressure chamber 33, and the second pressure chamber 35 and the second communication passage 36 are arranged point-symmetrically with respect to the nozzle 21.

[0030] 3, each of the first pressure chamber 33, the communication passage 34, and the second pressure chamber 35 has a through-hole that passes through the flow path plate 23b in the vertical direction, and a surface of the flow path plate 23b that surrounds the periphery of the through-hole, the upper surface of the nozzle plate 23a, and the lower surface of the vibration plate 23c. The first pressure chamber 33 and the second pressure chamber 35 have a rectangular parallelepiped shape and extend along the first extension direction, as shown in FIG. 4. A portion of the first pressure chamber 33 and a portion of the second pressure chamber 35 overlap each other when viewed along the first width direction that is perpendicular to the first extension direction.

[0031] The communicating passages 34 extend in the second extension direction and are connected to the first pressure chamber 33 and the second pressure chamber 35. As shown in Fig. 3, the first extension direction and the second extension direction are parallel to an opposing surface 23b1 of the flow path plate 23b in which the communicating passages 34 are formed. The opposing surface 23b1 is the lower surface of the flow path plate 23b and faces an opposing surface 23a2 of the nozzle plate 23a. The opposing surface 23a2 of the nozzle plate 23a is the surface opposite to the ejection surface 23a1 of the nozzle plate 23a in the stacking direction (e.g., the up-down direction) of the nozzle plates 23a and 23b, and is the upper surface of the nozzle plate 23a.

[0032] As shown in FIG. 4 , the first pressure chamber 33 has a first proximal end 33a and a first distal end 33b. The first proximal end 33a and the first distal end 33b are opposite ends of the first pressure chamber 33 in the first width direction and extend in the first extension direction. In the first width direction, the first distal end 33b is farther from the second pressure chamber 35 than the first proximal end 33a. The first pressure chamber 33 also has a first proximal end 33c and a first distal end 33d. The first proximal end 33c and the first distal end 33d are opposite ends of the first pressure chamber 33 in the first extension direction, extend in the first width direction, and are shorter than the first proximal end 33a and the first distal end 33b. In the first extension direction, the first distal end 33d is farther from the second pressure chamber 35 than the first proximal end 33c.

[0033] The second pressure chamber 35 has a second proximal end 35a and a second distal end 35b. The second proximal end 35a and the second distal end 35b are opposite ends of the second pressure chamber 35 in the first width direction and extend in the first extension direction. In the first width direction, the second distal end 35b is farther from the first pressure chamber 33 than the second proximal end 35a. The second pressure chamber 35 also has a second proximal end 35c and a second distal end 35d. The second proximal end 35c and the second distal end 35d are opposite ends of the second pressure chamber 35 in the first extension direction, extend in the first width direction, and are shorter than the second proximal end 35a and the second distal end 35b. In the first extension direction, the second distal end 35d is farther from the first pressure chamber 33 than the second proximal end 35c.

[0034] The communication passage 34 extends along a second extension direction different from the first extension direction and is connected to a first proximal end 33a of the first pressure chamber 33 and a second proximal end 35a of the second pressure chamber 35. The first proximal end 33a and the second proximal end 35a face each other in the first width direction. The first communication passage 32 extends from the first connection passage 31 along the first extension direction and is connected to a first distal end 33d of the first pressure chamber 33 so as to be aligned with the first distal end 33b of the first pressure chamber 33. The second communication passage 36 extends from the second connection passage 37 along the first extension direction and is connected to a second distal end 35d of the second pressure chamber 35 so as to be aligned with the second distal end 35b of the second pressure chamber 35.

[0035] As a result, in the individual paths 30, liquid flows from the first connecting path 31 into the first communicating path 32, flows through the first communicating path 32 along the first extension direction, and flows into the first distal end 33d of the first pressure chamber 33. The liquid flows through the first pressure chamber 33 along the first extension direction and flows into the communicating path 34 from the first proximal end 33a of the first pressure chamber 33. The liquid then flows through the communicating path 34 in the second extension direction, flows from the communicating path 34 into the second proximal end 35a of the second pressure chamber 35, and flows through the second pressure chamber 35 along the first extension direction. The liquid then flows into the second communicating path 36 from the second distal end 35d of the second pressure chamber 35, flows through the second communicating path 36 along the first extension direction, and flows into the second connecting path 37.

[0036] Thus, the liquid flows along the first extension direction in the first pressure chamber 33 and the second pressure chamber 35, but flows along the second extension direction in the communicating passage 34. When the liquid flows through the first pressure chamber 33, the communicating passage 34, and the second pressure chamber 35 in this order, the flow direction of the liquid changes from the first extension direction to the second extension direction and back again to the first extension direction. Therefore, even if air bubbles adhere to the walls of the first pressure chamber 33, the communicating passage 34, the second pressure chamber 35, etc., the changing flow of the liquid makes it easy for the air bubbles to be removed from the walls. Therefore, because the air bubbles are easily discharged from the first pressure chamber 33, the communicating passage 34, and the second pressure chamber 35, a decrease in discharge pressure due to the air bubbles is reduced, and poor discharge of the liquid from the nozzle 21 caused by the air bubbles can be suppressed.

[0037] Furthermore, because air bubbles are easily discharged from the first pressure chamber 33, the communicating passage 34, and the second pressure chamber 35, it is not necessary to provide a bubble discharge path for discharging air bubbles in the head 20. If the bubble discharge path were connected to the first pressure chamber 33, the communicating passage 34, and the second pressure chamber 35, the ejection pressure applied to the first pressure chamber 33 and the second pressure chamber 35 could escape via the bubble discharge path. In contrast, because the head 20 does not have a bubble discharge path, a decrease in the ejection pressure via the bubble discharge path is prevented, and poor ejection of liquid from the nozzles 21 due to the bubble discharge path can be suppressed.

[0038] The deflection angle θ when the liquid flowing in the first stretching direction in the first pressure chamber 33 flows in the second stretching direction in the communicating passage 34 is equal to or greater than 45 degrees and less than 90 degrees. This deflection angle θ is equal to the smaller of the angles formed by an imaginary line E1 along the first stretching direction and an imaginary line E2 along the second stretching direction.

[0039] In this way, by setting the deflection angle θ to 45 degrees or more, it is possible to increase the change in the flow of liquid in the first pressure chamber 33 and the flow of liquid in the communicating passage 34, making it easier for air bubbles to be removed from the wall surfaces in the first pressure chamber 33 and the communicating passage 34. Furthermore, by setting the deflection angle θ to less than 90 degrees, the flow direction of the liquid in the first pressure chamber 33 is easily changed to the flow direction of the liquid in the communicating passage 34, and this liquid flow makes it easier for air bubbles to flow from the first pressure chamber 33 to the communicating passage 34. By achieving both ease of air bubbles removal and ease of air bubbles flowing in this way, air bubbles are easily discharged from the first pressure chamber 33 through the communicating passage 34, making it possible to suppress poor discharge of liquid from the nozzle 21 caused by air bubbles and the bubble discharge path.

[0040] The communicating passage 34 has a first end 34a and a second end 34b, which are opposite ends of the communicating passage 34 in the second extension direction. The first end 34a is connected to the first pressure chamber 33, and the second end 34b is connected to the second pressure chamber 35. In a cross section parallel to the first extension direction and the second extension direction, the communicating passage 34 is connected to the first pressure chamber 33 and the second pressure chamber 35 so that, for example, a center 33e of the rectangular first pressure chamber 33 and a center 35e of the rectangular second pressure chamber 35 are aligned along the second extension direction.

[0041] The communicating passage 34 has an end in a depth direction intersecting (for example, perpendicular to) the first stretching direction and the second stretching direction, for example, a lower end in the up-down direction, connected to the nozzle 21. In this way, the communicating passage 34 is directly connected to the nozzle 21, and therefore, poor ejection of the liquid from the nozzle 21 can be suppressed.

[0042] That is, there may be cases where descenders extending in the vertical direction are connected between the first pressure chamber 33 and the communication passage 34, and between the second pressure chamber 35 and the communication passage 34. If these descenders make it difficult to discharge bubbles, a bubble discharge path may be provided in the head 20. In contrast, by directly connecting the communication passage 34 to the first pressure chamber 33 and the second pressure chamber 35, bubbles are more easily discharged than when descenders are provided between them, and therefore the drop in discharge pressure due to the bubbles and the bubble discharge path is reduced, and poor discharge of liquid from the nozzle 21 caused by the bubbles and the bubble discharge path can be suppressed.

[0043] 3, in the depth direction perpendicular to the first and second extension directions, the dimension C34 of the communicating passage 34 is the same as the dimension C33 of the first pressure chamber 33 and the dimension C35 of the second pressure chamber 35. For example, the communicating passage 34, the first pressure chamber 33, and the second pressure chamber 35 penetrate the flow path plate 23b in the vertical direction, with their lower ends defined by the upper surface of the nozzle plate 23a and their upper ends defined by the lower surface of the vibration plate 23c. In this case, the depth direction is parallel to the direction in which the nozzle plates 23a and the flow path plates 23b are stacked, e.g., the vertical direction. In the depth direction, the dimension C34 of the communicating passage 34, the dimension C33 of the first pressure chamber 33, and the dimension C35 of the second pressure chamber 35 are each equal to the distance between the nozzle plate 23a and the vibration plate 23c.

[0044] In this way, because the dimension C34 of the communicating passage 34 is the same as the dimension C33 of the first pressure chamber 33 and the dimension C35 of the second pressure chamber 35, the liquid tends to flow smoothly in this order through the first pressure chamber 33, the communicating passage 34, and the second pressure chamber 35. This flow of liquid tends to discharge bubbles easily from the first pressure chamber 33, the communicating passage 34, and the second pressure chamber 35, making it possible to suppress poor discharge of the liquid from the nozzle 21 caused by bubbles and the bubble discharge path.

[0045] Furthermore, the upper end of the communicating passage 34, the upper end of the first pressure chamber 33, and the upper end of the second pressure chamber 35 are flush with one another and are continuous. Furthermore, the lower end of the communicating passage 34, the lower end of the first pressure chamber 33, and the lower end of the second pressure chamber 35 are flush with one another and are continuous. As a result, there are no unevenness between the communicating passage 34 and the first pressure chamber 33 and the second pressure chamber 35 in the vertical direction, and the liquid tends to flow smoothly through the first pressure chamber 33, the communicating passage 34, and the second pressure chamber 35 in that order. This flow of liquid makes it easy for air bubbles to be discharged from the first pressure chamber 33, the communicating passage 34, and the second pressure chamber 35, and therefore it is possible to suppress poor discharge of liquid from the nozzle 21 caused by air bubbles and the air bubble discharge path.

[0046] 4, the dimension D34 of the communicating passage 34 in the second width direction perpendicular to the second extension direction is equal to or less than half the dimension D33 of the first pressure chamber 33 and the dimension D35 of the second pressure chamber 35 in the first width direction perpendicular to the first extension direction. The first width direction and the second width direction are different directions and are perpendicular to the depth direction.

[0047] In this way, because the dimension D34 of the communicating passage 34 is small, at less than half the dimension D33 of the first pressure chamber 33, the flow rate of the liquid flowing in from the first pressure chamber 33 is fast in the communicating passage 34. Furthermore, because the dimension D34 of the communicating passage 34 is small, at less than half the dimension D35 of the second pressure chamber 35, the flow rate of the liquid flowing out from the second pressure chamber 35 is fast in the communicating passage 34. This fast flow of liquid makes it easy for bubbles to be discharged from the first pressure chamber 33, the communicating passage 34, and the second pressure chamber 35, and therefore, poor discharge of the liquid from the nozzle 21 caused by bubbles and the bubble discharge path can be suppressed.

[0048] The piezoelectric element 27 is disposed above the first pressure chamber 33 and the second pressure chamber 35 via the vibration plate 23c. The piezoelectric element 27 extends along the first extension direction above the first pressure chamber 33, and extends along the first extension direction above the second pressure chamber 35. The ejection pressure applied by the piezoelectric element 27 propagates from the first pressure chamber 33 and the second pressure chamber 35 to the nozzle 21 via the communication passage 34. The propagation direction of this ejection pressure changes in the same manner as the flow direction of the liquid, so air bubbles adhering to the wall surfaces of the first pressure chamber 33 and the second pressure chamber 35 are easily removed. Therefore, air bubbles are easily discharged from the first pressure chamber 33 and the second pressure chamber 35, making it possible to suppress poor ejection of liquid from the nozzle 21 caused by air bubbles and the bubble discharge path.

[0049] <Variation 1> In the liquid ejection device 10 according to the first modification, as shown in FIG. 5, in the above embodiment, the first pressure chamber 33 and the second pressure chamber 35 each have a corner portion, and the communicating passage 34 is connected to the corner portion of the first pressure chamber 33 and the corner portion of the second pressure chamber 35.

[0050] Specifically, the first pressure chamber 33 and the second pressure chamber 35 do not overlap each other when viewed along the first width direction. The first pressure chamber 33 and the second pressure chamber 35 are, for example, rectangular parallelepiped shaped. The first pressure chamber 33 has four corners, called first corner portions 33f, and the second pressure chamber 35 has four corners, called second corner portions 35f.

[0051] The first corner portions 33f of the first pressure chamber 33 are provided between the first proximal end 33a and the first distal end 33b and the first proximal short end 33c, and between the first proximal end 33a and the first distal end 33b and the first distal short end 33d. The second corner portions 35f of the second pressure chamber 35 are provided between the second proximal end 35a and the second distal end 35b and the second proximal short end 35c, and between the second proximal end 35a and the second distal end 35b and the second distal short end 35d.

[0052] A first end 34a of the communicating passage 34 is connected to a first corner 33f1 of the four first corners 33f of the first pressure chamber 33 that is closest to the second pressure chamber 35. This first corner 33f1 is the first corner 33f between the first proximal long end 33a and the first proximal short end 33c. A second end 34b of the communicating passage 34 is connected to a second corner 35f1 of the four second corners 35f of the second pressure chamber 35 that is closest to the first pressure chamber 33. This second corner 35f1 is the second corner 35f between the second proximal long end 35a and the second proximal short end 35c.

[0053] As described above, in the first pressure chamber 33 and the second pressure chamber 35, which have corners, bubbles tend to accumulate in the corners. However, by connecting the communicating passage 34 to the first corner 33f1 of the first pressure chamber 33, liquid flows from the first corner 33f1 to the communicating passage 34, and bubbles are easily discharged from the first corner 33f1 by this liquid flow. Furthermore, by connecting the communicating passage 34 to the second corner 35f1 of the second pressure chamber 35, liquid flows from the communicating passage 34 to the second corner 35f1, and bubbles are easily discharged from the second corner 35f1 by this liquid flow. Therefore, poor discharge of liquid from the nozzle 21 due to bubbles and the bubble discharge path can be suppressed.

[0054] Furthermore, the first communication passage 32 is connected to a first corner 33f2, which is the first corner 33f of the first pressure chamber 33. This first corner 33f2 is diagonally opposite the first corner 33f1 to which the communication passage 34 is connected. Furthermore, the second communication passage 36 is connected to a second corner 35f2, which is the second corner 35f of the second pressure chamber 35. This second corner 35f2 is diagonally opposite the second corner 35f1 to which the communication passage 34 is connected.

[0055] In this way, the first corner 33f1 to which the communicating passage 34 is connected and the first corner 33f2 to which the first communicating passage 32 is connected are diagonal corners of the first pressure chamber 33. This reduces unevenness in the flow of liquid in the first pressure chamber 33 when the liquid flows from the first communicating passage 32 into the first pressure chamber 33 and flows out to the communicating passage 34. Furthermore, the second corner 35f1 to which the communicating passage 34 is connected and the second corner 35f2 to which the second communicating passage 36 is connected are diagonal corners of the second pressure chamber 35. This reduces unevenness in the flow of liquid in the second pressure chamber 35 when the liquid flows from the communicating passage 34 into the second pressure chamber 35 and flows out to the second communicating passage 36. This flow of liquid makes it easy to discharge bubbles from the first pressure chamber 33 and the second pressure chamber 35, thereby preventing poor discharge of liquid from the nozzle 21 caused by bubbles and the bubble discharge path.

[0056] 5 is similar to the communicating passage 34 in Fig. 4 except for the points of connection to the first pressure chamber 33 and the second pressure chamber 35. Therefore, for example, the dimension C34 of the communicating passage 34 is the same as the dimension C33 of the first pressure chamber 33 and the dimension C35 of the second pressure chamber 35, and the upper end of the communicating passage 34, the upper end of the first pressure chamber 33, and the upper end of the second pressure chamber 35 are continuous and on the same plane, and the lower end of the communicating passage 34, the lower end of the first pressure chamber 33, and the lower end of the second pressure chamber 35 are continuous and on the same plane. This makes it easier for air bubbles to be discharged from the first pressure chamber 33, the communicating passage 34, and the second pressure chamber 35, thereby preventing poor discharge of liquid from the nozzle 21 due to air bubbles and the air bubble discharge path.

[0057] Furthermore, the deflection angle θ when the liquid flowing in the first extension direction in the first pressure chamber 33 flows in the second extension direction in the communicating passage 34 is equal to or greater than 45 degrees and less than 90 degrees. Such a deflection angle θ changes the flow direction of the liquid flowing from the first pressure chamber 33 to the communicating passage 34, and facilitates a smooth flow of the liquid from the first pressure chamber 33 to the communicating passage 34. This liquid flow facilitates the discharge of air bubbles from the first pressure chamber 33 through the communicating passage 34, thereby suppressing poor discharge of the liquid from the nozzle 21 caused by the air bubbles and the bubble discharge path.

[0058] <Variation 2> In the liquid ejection device 10 according to the second modification, in the above-described embodiment and the first modification, as shown in FIG. 6, the first pressure chamber 33 and the second pressure chamber 35 each have a curved corner portion in a cross section parallel to the first extension direction and the second extension direction.

[0059] Specifically, each of the first pressure chamber 33 and the second pressure chamber 35 has a rectangular cross section parallel to the first extension direction and the second extension direction. The first pressure chamber 33 has four first corners 33f, and the second pressure chamber 35 has four second corners 35f. The first corners 33f and the second corners 35f are curved in cross section. This allows air bubbles in the first pressure chamber 33 to move easily along the curved first corners 33f and are therefore easily discharged from the first pressure chamber 33. Similarly, in the second pressure chamber 35, air bubbles to move easily along the curved second corners 35f and are therefore easily discharged from the second pressure chamber 35. This makes it possible to suppress poor discharge of liquid from the nozzle 21 caused by air bubbles and their bubble discharge paths.

[0060] 6, the communication passage 34 is connected to the first proximal end 33a of the first pressure chamber 33 and the second proximal end 35a of the second pressure chamber 35. However, as long as the second extension direction of the communication passage 34 differs from the first extension directions of the first pressure chamber 33 and the second pressure chamber 35, the connection points of the communication passage 34 to the first pressure chamber 33 and the second pressure chamber 35 are not limited to this. For example, the communication passage 34 may be connected to a first corner portion 33f of the first pressure chamber 33 and a second corner portion 35f of the second pressure chamber 35.

[0061] It should be noted that many modifications and other embodiments of the present disclosure will be apparent to those skilled in the art from the above description. Therefore, the above description should be construed as merely illustrative and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the present disclosure. Details of the structure and / or function thereof may be substantially changed without departing from the spirit of the present disclosure. [Explanation of symbols]

[0062] 10:Liquid discharge device 21: Nozzle 23a: Nozzle plate 23a1:Discharge surface 23a2: Opposite side 23b: Flow path plate 23b1: Opposite surface 24: Supply manifold 25: Recovery manifold 33: First pressure chamber 33f: 1st corner part (corner part) 34:Communication path 34a: 1st end 34b: 2nd end 35: Second pressure chamber 35f: 2nd corner part (corner part)

Claims

1. a plurality of first pressure chambers extending in a first extension direction; a plurality of second pressure chambers extending in the first extension direction; a communication passage extending in a second extension direction different from the first extension direction and connected to the first pressure chamber and the second pressure chamber; a nozzle connected to the communication passage and configured to eject a liquid; a supply manifold that communicates with the plurality of first pressure chambers and supplies liquid; a recovery manifold communicating with the plurality of second pressure chambers to recover liquid, the communication path has a first end and a second end that are opposite ends in the second extension direction, the first end is connected to the first pressure chamber; the second end is connected to the second pressure chamber; Liquid discharge device.

2. each of the first pressure chamber and the second pressure chamber has a corner portion; the communication passage is connected to the corner portion of the first pressure chamber and the corner portion of the second pressure chamber. The liquid ejection device according to claim 1 .

3. each of the first pressure chamber and the second pressure chamber has a curved corner portion in a cross section parallel to the first extension direction and the second extension direction; The liquid ejection device according to claim 1 .

4. a deflection angle of the liquid flowing in the first extension direction in the first pressure chamber when the liquid flows in the second extension direction in the communication passage is equal to or greater than 45 degrees and less than 90 degrees; The liquid ejection device according to claim 1 .

5. a dimension of the communication passage in a depth direction perpendicular to the first extension direction and the second extension direction is the same as a dimension of the first pressure chamber and a dimension of the second pressure chamber; The liquid ejection device according to claim 1 .

6. a dimension of the communication passage in a second width direction perpendicular to the second extension direction is equal to or less than half a dimension of the first pressure chamber and a dimension of the second pressure chamber in a first width direction perpendicular to the first extension direction; The liquid ejection device according to claim 1 .

7. a nozzle plate in which the nozzles are formed; a flow path plate laminated on the nozzle plate, in which the first pressure chamber, the second pressure chamber, and the communication path are formed, The liquid ejection device according to claim 1 .

8. the nozzle plate has an ejection surface on which the nozzles open and an opposite surface opposite to the ejection surface, the flow path plate has an opposing surface facing the opposite surface, The first extension direction and the second extension direction are parallel to the opposing surface. The liquid ejection device according to claim 7 .

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