Liquid ejection head

Abstract

To provide a liquid ejection head that facilitates recovery of air accumulated in a supply integration channel.SOLUTION: A liquid ejection head includes: a plurality of supply manifolds that has a long dimension, are parallelly provided in a width direction crossing a longitudinal direction thereof, and supply liquid to a nozzle; a plurality of return manifolds that extend in a longitudinal direction, are parallelly provided in the width direction, and into which liquid that has not been ejected by the nozzle flows; a plurality of individual channels whose upstream ends are connected to the supply manifolds, whose downstream ends are connected to the return manifolds, and individually communicate with a plurality of nozzles arranged in a line in the longitudinal direction of the supply manifolds; a supply integration channel that is provided at one end of the supply manifolds in the longitudinal direction and supplies liquid to the plurality of supply manifolds; a recovery integration channel that is provided at one ends in the longitudinal direction of the supply manifolds and recovers liquid from the plurality of return manifolds; and a bypass channel connecting the supply integration channel and the recovery integration channel.SELECTED DRAWING: Figure 8

Description

[Technical field]

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

[0002] As a printing head, for example, a liquid ejection head that prints by ejecting liquid such as ink onto a printing medium is known. For example, Patent Document 1 discloses a circulation head configured to recover liquid that is supplied from a supply manifold and not ejected by a nozzle in a return manifold, and then return the liquid to the supply manifold. In this circulation head, a supply integrated flow path is provided on one side in the longitudinal direction of the supply manifold, and a recovery integrated flow path is provided on the other side in the longitudinal direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6600122 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional configuration, there was a risk that air in the integrated supply channel would not be discharged and would remain in the integrated supply channel, which could cause the air in the integrated supply channel to enter the nozzles, which could cause the nozzles to be unable to eject droplets.

[0005] SUMMARY OF THE PRESENTLY PREFERRED EMBODIMENTS In view of the above, an object of the present invention is to provide a liquid ejection head that makes it easy to collect air that has accumulated in the integrated supply channel. [Means for solving the problem]

[0006] The liquid ejection head of the present invention comprises a plurality of supply manifolds which are long and arranged side by side in a width direction intersecting the longitudinal direction, and which supply liquid to the nozzles; a plurality of return manifolds which extend in the longitudinal direction and are arranged side by side in the width direction, and into which liquid not ejected by the nozzles flows; a plurality of individual flow paths each having an upstream end connected to the supply manifold and a downstream end connected to the return manifold, and which individually communicate with a plurality of nozzles arranged in a row in the longitudinal direction of the supply manifold; an integrated supply flow path which is provided at one longitudinal end of the supply manifold, and which supplies liquid to the plurality of supply manifolds; an integrated recovery flow path which is provided at one longitudinal end of the supply manifold, and which recovers liquid from the plurality of return manifolds; and a bypass flow path which connects the integrated supply flow path and the integrated recovery flow path.

[0007] According to the present invention, by providing a bypass passage connecting the integrated supply passage and the integrated return passage, air accumulated in the integrated supply passage can be discharged to the integrated return passage via the bypass passage. Also, since the integrated supply passage and the integrated return passage are gathered at one end of the supply manifold in the longitudinal direction, the bypass passage can be made short, which makes it easier to discharge air. Effect of the Invention

[0008] According to the present invention, it is possible to provide a liquid ejection head that makes it easy to collect air that has accumulated in the integrated supply channel. [Brief description of the drawings]

[0009] [Figure 1] 1 is a plan view showing a schematic configuration of a liquid ejection device including a liquid ejection head according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view of the liquid ejection head of FIG. [Diagram 3] 3 is a plan view showing the configuration of the liquid ejection head of FIG. 2 excluding a second flow path member. [Figure 4] 2 is a cross-sectional view of a first flow path member of the liquid ejection head of FIG. 1. [Diagram 5]FIG. 4 is a plan view of a second flow path member. [Figure 6] FIG. 4 is a plan view of a plate that constitutes a second flow path member. [Figure 7] FIG. 1(a) is a plan view of a plate constituting the second flow path member, (b) is a side view of the plate in (a), and (c) is a bottom view of the plate in (a). [Figure 8] 1(a) and (b) are plan views of a plate constituting the second flow path member. [Figure 9] 1(a) and (b) are plan views of a plate constituting the second flow path member. [Figure 10] FIG. 13 is a plan view showing a modified example of one plate of the second flow path member. [Figure 11] FIG. 13 is a diagram showing a connecting channel that connects the supply integrated channel and the supply manifold, and a filter disposed at a supply side position. [Figure 12] FIG. 13 is a diagram showing that a filter is not disposed at the recovery side position. [Figure 13] FIG. 13A is a diagram showing a modified example of the shape of the supply integrated channel, and FIG. 13B is a diagram showing an individual integrated channel. [Figure 14] 13 is a plan view showing a bypass flow path and a liquid supply path provided in a plate of a second flow path member. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A liquid ejection head according to an embodiment of the present invention will be described below with reference to the drawings. The liquid ejection head described below is merely one embodiment of the present invention. Therefore, the present invention is not limited to the following embodiment, and additions, deletions, and modifications are possible without departing from the spirit of the present invention.

[0011] The liquid ejection head 3 according to this embodiment is provided in, for example, a liquid ejection device 110. This liquid ejection device 110 ejects liquid such as ink. Below, an example in which the liquid ejection device 110 is applied to an inkjet printer will be described, but the application of the liquid ejection device 110 is not limited to this.

[0012] 1, the liquid ejection device 110 employs, for example, a line head system, and includes a platen 111, a conveying unit, a head unit 116, and a tank 112. However, the liquid ejection device 110 is not limited to the line head system, and may employ other systems, such as a serial head system.

[0013] The platen 111 is a flat member, and the ejection receiving medium paper PP is placed on its upper surface, and plays a role in determining the distance between the paper PP and the head unit 116 .

[0014] The transport section has two transport rollers 115 and a transport motor (not shown). The two transport rollers 115 are connected to the transport motor and are arranged parallel to each other along a direction perpendicular to the transport direction of the paper PP (the perpendicular direction) with the platen 111 sandwiched between them. When the transport motor is driven, the transport rollers 115 rotate, thereby transporting the paper PP on the platen 111 in the transport direction.

[0015] The head unit 116 has a length equal to or greater than the length of the paper PP in the orthogonal direction.

[0016] In the liquid ejection head 3, a plurality of nozzle holes (nozzles) 9 shown in Fig. 4 are opened in an ejection surface (nozzle surface) SF2. A meniscus vibrates in the nozzle holes 9, thereby ejecting liquid. The liquid ejection head 3 will be described in detail later.

[0017] When the liquid is, for example, ink, a tank 112 is provided for each type of ink. For example, four tanks 112 are provided, and black, yellow, cyan, and magenta ink are stored in each tank 112. The ink in the tanks 112 is supplied to the corresponding nozzle holes 9.

[0018] 2 is a plan view of the liquid ejection head 3 of FIG. 1, and FIG. 3 is a plan view showing the configuration of the liquid ejection head 3 of FIG. 2 excluding the second flow path member 7. As shown in FIG.

[0019] As shown in Fig. 2, the liquid ejection head 3 of this embodiment includes a first flow path member 5, a second flow path member 7 that supplies liquid to the first flow path member 5, and a piezoelectric actuator substrate 41 including a displacement element 51 that serves as a pressurizing section. The first flow path member 5 and the second flow path member 7 each extend in a longitudinal direction. In this embodiment, the longitudinal direction is the extension direction of a supply manifold 21, which will be described later. The width direction in Figs. 2 and 3 is a direction perpendicular to the longitudinal direction.

[0020] An opening 25b is provided on one end side in the longitudinal direction on the upper surface of the second flow path member 7, and an opening 27b is provided on the other end side in the longitudinal direction. Liquid from the outside is supplied to the second flow path member 7 through the opening 25b, and liquid that is not discharged in the first flow path member 5 described below is collected from the second flow path member 7 through the opening 27b. Note that the second flow path member 7 is provided with a through hole 19a, and a signal transmission unit (FPC: Flexible Printed Circuit) (not shown) for sending signals to each displacement element 51 is electrically connected to a control unit (not shown) via the through hole 19a.

[0021] 3, a plurality of elongated supply manifolds 21 and a plurality of elongated return manifolds 23 are provided to extend in the longitudinal direction in the first flow path member 5. Each return manifold 23 is disposed below the corresponding supply manifold 21.

[0022] The supply manifold 21 has openings 21b at both ends in the longitudinal direction. The return manifold 23 has openings 23b at both ends in the longitudinal direction and on the outer side of the openings 21b of the supply manifold 21 in the longitudinal direction.

[0023] In this configuration, in the first flow path member 5, the liquid supplied from the second flow path member 7 to each supply manifold 21 through each opening 21b flows toward the center of the supply manifold 21. The liquid then flows into a plurality of pressure chambers 11 (described below) corresponding to each supply manifold 21, and then a portion of the liquid is ejected from the nozzle holes 9. On the other hand, the liquid that is not ejected from the nozzle holes 9 flows into the return manifold 23 and is discharged to the outside from the first flow path member 5 through each opening 23b.

[0024] Next, a description will be given of the cross-sectional configuration of the first flow path member 5 in the liquid ejection head 3. FIG.

[0025] As shown in Fig. 4, the first flow path member 5 has a layered structure in which a number of plates are stacked. The piezoelectric actuator substrate 41 has a layered structure including two piezoelectric ceramic layers 41a and 41b, which are piezoelectric bodies. The lower surface of the piezoelectric ceramic layer 41b serves as the pressure chamber surface SF1. A number of pressure chambers 11 are arranged in the longitudinal direction (i.e., the direction of the nozzle row) on the pressure chamber surface SF1. Furthermore, a number of nozzle holes 9 that eject liquid are arranged in the longitudinal direction on the ejection surface SF2.

[0026] The first flow path member 5 has, for example, plates 5a to 5l. Plate 5a is connected to the pressurizing chamber surface SF1, which is the lower surface of the piezoelectric ceramic layer 41b. Plates 5b to 5l are laminated in this order below plate 5a. Holes and grooves of various sizes are formed in each plate. The holes and grooves are combined inside a flow path forming body formed by laminating the plates to form a plurality of nozzle holes 9, a plurality of individual flow paths 60, which will be described later, a supply manifold 21, and a return manifold 23 as liquid flow paths. The above-mentioned openings 21b and openings 23b are provided in the pressurizing chamber surface SF1. Furthermore, the nozzle holes 9 are opened in the ejection surface SF2.

[0027] The nozzle holes 9 are formed penetrating the plate 5l in the stacking direction (height direction). In the ejection surface SF2 of the plate 5l, the tips of the multiple nozzle holes 9 are aligned in the nozzle row direction.

[0028] The pressure chamber 11 is composed of a pressure chamber body 11a facing the displacement element 51 and a descender 11b having a smaller cross-sectional area than the pressure chamber body 11a. The pressure chamber body 11a is formed in the plate 5a. The descender 11b is formed across the plates 5b to 5k.

[0029] The pressurizing chamber main body 11a and the supply manifold 21 are connected by a supply throttle passage 13. That is, the supply throttle passage 13 individually connects each pressurizing chamber main body 11a to the supply manifold 21. The supply throttle passage 13 is formed by a hole penetrating plate 5b, a groove penetrating plate 5c, and a hole penetrating plate 5d.

[0030] The descender 11b and the return manifold 23 are connected by a return throttle passage 15. That is, the return throttle passage 15 individually connects each descender 11b to the return manifold 23. The return throttle passage 15 is formed by a groove 15aa that is adjacent to a hole formed in the plate 5k of the descender 11b and passes through the plate 5k, a groove 15ab that passes through the plate 5j, and a groove 15b that is adjacent to a hole formed in the plate 5i of the return manifold 23 and passes through the plate 5i.

[0031] In this embodiment, a flow path including the supply throttle path 13, the pressurizing chamber 11 (the pressurizing chamber main body 11a and the descender 11b), and the return throttle path 15 becomes an individual flow path 60. The individual flow path 60 is connected to the supply manifold 21 and the return manifold 23. More specifically, the individual flow path 60 has an upstream end connected to the supply manifold 21 and a downstream end connected to the return manifold 23, and is connected to the base end of the nozzle hole 9 between them.

[0032] Supply manifold 21 is formed by overlapping holes penetrating plates 5e and 5f. A damper chamber 30A is provided below supply manifold 21. Damper chamber 30A is formed by half-etching the lower half of plate 5g in the thickness direction. As a result, a thin-walled damper portion 29A is formed below supply manifold 21.

[0033] The feedback manifold 23 is formed by overlapping holes penetrating the plates 5i and 5j. A damper chamber 30B is provided below the feedback manifold 23. The damper chamber 30B is formed by half-etching the lower half of the plate 5k in the thickness direction. As a result, a thin-walled damper portion 29B is formed below the feedback manifold 23.

[0034] The displacement elements 51 of the piezoelectric actuator substrate 41 are provided so as to be located above the pressure chambers 11 described above. Also, individual electrodes 45 are provided at positions facing each pressure chamber 11 in the height direction. The individual electrodes 45 are electrically connected to a driver IC. This driver IC receives a control signal from a control unit (not shown) to generate a drive signal and applies the drive signal to the individual electrodes 45.

[0035] A common electrode 43 is provided between the piezoelectric ceramic layer 41a and the piezoelectric ceramic layer 41b in the piezoelectric actuator substrate 41. The common electrode 43 is provided so as to cover each of the pressure chambers 11. The common electrode 43 is always maintained at the ground potential. The piezoelectric ceramic layer 41b functions as a vibration plate.

[0036] The active portion of the piezoelectric ceramic layer 41a on which the individual electrode 45 overlaps expands and contracts in the planar direction together with the individual electrode 45 and the common electrode 43 in response to the drive signal. In response to this, the piezoelectric ceramic layer 41b, which is a vibration plate, deforms in cooperation with the individual electrode 45 and the common electrode 43, changing in a direction to increase or decrease the volume of the pressure chamber 11. As a result, an ejection pressure for ejecting liquid from the nozzle hole 9 is applied to the pressure chamber 11 in accordance with the volume of the pressure chamber 11.

[0037] In this configuration, the liquid first flows from the supply manifold 21 into the supply throttle passage 13, and then flows from the supply throttle passage 13 into the pressurized chamber 11. The liquid then flows through the descender 11b and into the nozzle hole 9. When the above-mentioned discharge pressure is applied to the pressurized chamber 11 in this state, the liquid is discharged from the nozzle hole 9.

[0038] On the other hand, a portion of the liquid that is not ejected from the nozzle holes 9 flows through the return throttle passage 15 and then flows into the return manifold 23. Then, the liquid that has flowed into the return manifold 23 flows inside the return manifold 23 and returns to the second flow path member 7.

[0039] Next, the second flow path member in this embodiment will be described in detail. Fig. 5 is a plan view of the second flow path member 7. Fig. 6 is a plan view of the plate 7a constituting the second flow path member 7. Fig. 7(a) is a plan view of the plate 7b constituting the second flow path member 7, (b) is a side view of the plate 7b in (a), and (c) is a bottom view of the plate 7b in (a). Figs. 8(a) and (b) are plan views of the plates 7c and 7d constituting the second flow path member 7, respectively. Figs. 9(a) and (b) are plan views of the plates 7e and 7f constituting the second flow path member 7.

[0040] As shown in FIG. 5, the second flow path member 7 is bonded to the pressurizing chamber surface SF1 of the first flow path member 5. The second flow path member 7 is composed of plates 7a to 7f, which are etched plates stacked in order from the top. Plate 7f shown in FIG. 9(b) is provided with a storage space 19 for storing the above-mentioned piezoelectric actuator substrate 41. The second flow path member 7 has a supply integrated flow path 25 that supplies liquid to the supply manifold 21, and a recovery integrated flow path 27 that recovers liquid from the return manifold 23. The supply integrated flow path 25 includes an opening 25b, a member 25a1, a storage section 25a2, a branch flow path 25a3, and a branch flow path 25a4, which will be described later. In addition, the recovery integrated flow path 27 includes an opening 27b, a member 27a1, a storage section 27a2, a branch flow path 27a3, and a branch flow path 27a4, which will be described later.

[0041] As shown in FIG. 6, an opening 25b is disposed at one end of the second flow path member 7 in the longitudinal direction, opening into the upper surface of the plate 7a of the second flow path member 7. The flow path configuration of the supply integrated flow path 25 starts from the upstream opening 25b, and is provided with a portion 25a1 and a storage section 25a2 as shown in FIG. 7(a). On the downstream side of the storage section 25a2, a branch flow path 25a3 extending in the longitudinal direction is provided as shown in FIG. 8(b). The branch flow path 25a3 is branched into two flow paths extending to one side and the other side in the longitudinal direction at the center of the longitudinal direction. A branch flow path 25a4 extending in the width direction is connected to each of the ends of the flow path on the one side and the other side of the branch flow path 25a3 as shown in FIG. 8(b) and FIG. 9(a) and (b). Each of the branch flow paths 25a4 branches out to one side and the other side in the width direction of the second flow path member 7, and is connected to the above-mentioned opening 21b in the supply manifold 21 of the first flow path member 5.

[0042] On the other hand, at the other end of the second flow path member 7 in the longitudinal direction, an opening 27b is arranged on the upper surface of the plate 7a of the second flow path member 7 as shown in FIG. 6. The flow path configuration of the recovery integrated flow path 27 starts from the upstream opening 27b, and is provided with a portion 27a1 and a storage section 27a2 as shown in FIG. 7(a). On the downstream side of the storage section 27a2, a branch flow path 27a3 extending in the longitudinal direction as shown in FIG. 8(b) is provided. The branch flow path 27a3 is branched at the center in the longitudinal direction into two flow paths extending on one side and the other side in the longitudinal direction. The branch flow path 27a4 extending in the width direction is connected to each of the ends of the flow path on the one side and the other side of the branch flow path 27a3 as shown in FIG. 8(b) and FIG. 9(a) and (b). Each of the branch flow paths 27a4 branches off to one side and the other side in the width direction of the second flow path member 7, and is connected to the above-mentioned opening 23b in the return manifold 23 of the first flow path member 5. In plan view, the branch flow paths 25a3 and 27a3 are arranged to at least partially overlap each other. In the above configuration, when printing is performed, liquid is supplied from the outside to the opening 25b of the integrated supply flow path 25, and the liquid not ejected by the nozzle holes 9 is recovered from the opening 27b of the integrated recovery flow path 27.

[0043] Here, as shown in FIG. 5 and FIG. 8(b), the second flow path member 7 is provided with a bypass flow path 65 that connects the above-mentioned supply integrated flow path 25 and the above-mentioned recovery integrated flow path 27. In detail, as shown in FIG. 8(b), the bypass flow path 65 includes each one-side bypass flow path 65a that connects one end in the width direction of each branch flow path 25a4 to one end of each branch flow path 27a4 on both one side and the other side in the longitudinal direction. In addition, the bypass flow path 65 includes the other-side bypass flow path 65b that connects the other end in the width direction of the branch flow path 25a4 to the other end of the branch flow path 27a4 on both one side and the other side in the longitudinal direction. The flow path resistance of the bypass flow path 65 is higher than the combined resistance of the flow paths from the supply manifold 21 through the nozzle holes 9 to the return manifold 23, specifically, the combined resistance of the flow paths from the supply manifold 21 through the individual flow paths 60 to the return manifold 23.

[0044] As described above, according to the liquid ejection head 3 of this embodiment, by providing the bypass flow path 65 that connects the integrated supply flow path 25 and the integrated recovery flow path 27, air accumulated in the integrated supply flow path 25 can be discharged to the integrated recovery flow path 27 via the bypass flow path 65. Also, since the integrated supply flow path 25 and the integrated recovery flow path 27 are gathered at one end of the supply manifold 21 in the longitudinal direction, the bypass flow path 65 can be shortened, and therefore, air can be easily discharged. Furthermore, during purging and when the printing duty is high, air in the integrated supply flow path 25 is drawn into the second flow path member 7, and therefore, the risk of the nozzle holes 9 being blocked can be reduced.

[0045] In this embodiment, the bypass flow passage 65 includes a one-side bypass flow passage 65a and an other-side bypass flow passage 65b. By providing the bypass flow passages 65 at both ends in the longitudinal direction of the integrated supply flow passage 25 (the branch flow passages 25a4 of the integrated supply flow passage 25), the performance of discharging air from within the integrated supply flow passage 25 can be improved.

[0046] Furthermore, in this embodiment, the flow path resistance of the bypass flow path 65 is higher than the combined resistance of the flow paths from the supply manifold 21 to the return manifold 23 via the nozzle holes 9, specifically, the combined resistance of the flow paths from the supply manifold 21 to the return manifold 23 via the individual flow paths 60. In this case, by minimizing the flow rate of liquid in the bypass flow path 65, it is possible to ensure a sufficient amount of liquid in the flow path from the supply manifold 21 to the return manifold 23 via the nozzle holes 9.

[0047] <Modification> The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the present invention. For example, the following modifications are possible.

[0048] 10, a bypass flow path 165 may be formed in at least the uppermost plate 7a among the above-mentioned multiple plates 7a to 7f. In this case, the bypass flow path 165 may be formed in the plates 7a, 7b, and 7c. This can further improve the discharge performance of air.

[0049] As shown in FIG. 11, a filter FT may be attached to the supply integrated flow path 25 (branch flow path 25a4 of the supply integrated flow path 25) at a position P1 between the bypass flow path 65 and the supply manifold 21 (more specifically, at a position directly above the second flow path member 7). In this case, even if the filter FT is provided, air can be discharged through the bypass flow path 65, and therefore air discharge is not hindered. In contrast, as shown in FIG. 12, no filter is provided in the recovery integrated flow path 27 (branch flow path 27a4 of the recovery integrated flow path 27). In this case, it is possible to avoid providing a filter unnecessarily.

[0050] 13(a), a flow path 125a4 formed in a plurality of plates (e.g., plates 7d, 7e, 7f) may be used as a modified example of the branch flow path 25a4 of the supply integrated flow path 25. The flow path 125a4 is formed by combining the openings of the stacked plates 7d, 7e, 7f, and the openings of the upper plates among the plates 7d, 7e, 7f are smaller to form a tapered shape. By using such a flow path 125a4, it becomes easier to discharge the air in the supply integrated flow path 25.

[0051] 13(b), a plurality of individual integrated flow paths 225a4 may be formed in plates 7e and 7f, each of which is individually connected to a respective one of the plurality of supply manifolds 21. The individual integrated flow path 225a4 includes an individual flow path 72 formed in plate 7e and an individual flow path 73 formed in plate 7f. The dimension in the width direction of the individual integrated flow path 225a4 is the same as the dimension in the width direction of the supply manifold 21. In this case, it becomes easier to discharge air inside the supply integrated flow path 25.

[0052] As shown in FIG. 14, the bypass flow path 65 includes one-side bypass flow paths 65a connecting one end of each branch flow path 25a4 in the width direction to one end of each branch flow path 27a4 on both one side and the other side in the longitudinal direction. The bypass flow path 65 also includes another-side bypass flow path 65b connecting the other end of the branch flow path 25a4 in the width direction to the other end of the branch flow path 27a4 on the other side in the longitudinal direction. Here, the plate 7d of the second flow path member 7 is provided with a liquid supply path 66. In this case, in an aspect in which the one-side half of the branch flow path 25a3 in the longitudinal direction is not provided, the liquid supply path 66 connects one end of the branch flow path 25a3 in the longitudinal direction to the other end of the branch flow path 25a4 arranged on one side in the width direction. With this configuration, the liquid can be smoothly flowed in the supply integrated flow path 25. In addition, in FIG. 14, the liquid supply path 66 is provided only on one side in the longitudinal direction, but this is not limited to this. The liquid supply path 66 may be provided in the same manner as on one side in the longitudinal direction, without providing the other-side bypass flow path 65b on the other side in the longitudinal direction.

[0053] Furthermore, in the above embodiment, the damper portion 29B is formed below the return manifold 23, but this damper portion 29B is not an essential component, and there does not need to be a damper portion below the return manifold 23. [Explanation of symbols]

[0054] 3 Liquid ejection head 9 Nozzle hole 21 Supply Manifold 23 Feedback manifold 25 Supply integrated flow path 27 Integrated recovery channel 65,165 Bypass flow path 65a One-side bypass flow path 65b Other side bypass flow path 66 Liquid supply path 225a4 Individual integrated flow path FT Filter

Claims

1. a plurality of supply manifolds each having an elongated dimension and arranged in a width direction intersecting the longitudinal direction, the supply manifolds supplying liquid to the nozzles; a plurality of return manifolds extending in the longitudinal direction and arranged side by side in the width direction, into which liquid not ejected by the nozzles flows; a plurality of individual flow paths each having an upstream end connected to the supply manifold and a downstream end connected to the return manifold, the individual flow paths being individually connected to a plurality of nozzles arranged in a row in the longitudinal direction of the supply manifold; a supply integration channel provided at one end of the supply manifold in the longitudinal direction and supplying liquid to the plurality of supply manifolds; a recovery and integration flow path provided at one end of the supply manifold in the longitudinal direction and configured to recover liquid from the plurality of return manifolds; a bypass flow path connecting the integrated supply flow path and the integrated recovery flow path; the integrated supply channel has a first branch channel connected to the plurality of supply manifolds at one end in the longitudinal direction, the integrated recovery channel has a second branch channel connected to the plurality of return manifolds at one end on the same side as the first branch channel in the longitudinal direction, The bypass flow path is directly connected to both the first branch flow path and the second branch flow path.

2. the supply integration channel extends in the width direction across the plurality of supply manifolds; The liquid ejection head according to claim 1 , wherein the bypass flow path includes a one-end bypass flow path provided on one end side of the integrated supply flow path in the width direction, and an other-end bypass flow path provided on the other end side of the integrated supply flow path in the width direction.

3. the supply integration channel extends in the width direction across the plurality of supply manifolds; The bypass flow path includes a one-end bypass flow path provided on one end side of the supply integrated flow path in the width direction, The liquid ejection head according to claim 1 , further comprising a liquid supply passage having one end connected to the other end side in the width direction of the integrated supply channel.

4. The supply integration channel is formed by a plurality of stacked plates, The liquid ejection head according to claim 1 , wherein the bypass flow path is formed in at least an uppermost plate of the plurality of plates.

5. 5. The liquid ejection head according to claim 1, wherein a flow resistance of the bypass flow path is higher than a combined resistance of the flow paths extending from the supply manifold through the nozzles to the return manifold.

6. the supply integration channel includes a plurality of individual integration channels each individually connected to each of the plurality of supply manifolds, The liquid ejection head according to claim 5 , wherein a dimension of the individual integrated flow passage in the width direction is the same as a dimension of the supply manifold in the width direction.

7. The liquid ejection head according to claim 1 , further comprising a filter disposed in the integrated supply channel at a position between the bypass channel and the supply manifold.

8. The liquid ejection head according to claim 1 , wherein a filter is not disposed in the integrated recovery channel.

9. 9. A liquid ejection head as claimed in claim 1, wherein the integrated supply flow path is formed by combining openings of a plurality of stacked plates, and the openings of the upper plates are smaller than those of the upper plates, forming a tapered shape.

10. The supply integrated flow path further has a third branch flow path connected to the plurality of supply manifolds at the other longitudinal end, The integrated recovery channel further includes a fourth branch channel connected to the plurality of return manifolds at the other end on the same side as the third branch channel in the longitudinal direction, the one-end-side bypass flow path includes a bypass flow path connecting one end of the first branch flow path in the width direction and one end of the second branch flow path in the width direction, and a bypass flow path connecting one end of the third branch flow path in the width direction and one end of the fourth branch flow path in the width direction, The liquid ejection head according to claim 2, wherein the other end side bypass flow path includes a bypass flow path connecting the other end of the first branch flow path in the width direction to the other end of the second branch flow path in the width direction, and a bypass flow path connecting the other end of the third branch flow path in the width direction to the other end of the fourth branch flow path in the width direction.

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