Liquid ejection head

Abstract

To provide a liquid discharge head that facilitates securement of required pressure loss.SOLUTION: A liquid discharge head comprises: a supply manifold to which liquid is supplied from the outside; a return manifold 23 from which liquid is ejected to the outside; and a plurality of individual passages, whose upstream ends are communicated with the supply manifold and whose downstream ends are communicated with the return manifold, which are individually communicated with a plurality of nozzles arranged on nozzle surfaces in line. Each of the plurality of individual passages includes a pressure chamber, a descender communicating with the pressure chamber, a return throttled passage 31 communicating with the return manifold, and an interposed passage 80 interposed between the return throttled passage and the descender and communicated with the nozzle. The return throttled passage extends in a second direction which is different from a first direction that is a direction in which the intervening passage extends, where passage cross sectional areas of the return throttled passage are smaller than passage cross sectional areas of the interposed passage.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] Conventionally, a configuration is known that includes a supply manifold and a return manifold to circulate ink between an ink tank and a liquid ejection head. As an example of such a liquid ejection head, Patent Document 1 discloses a configuration that effectively removes air bubbles near the nozzle by providing a first portion that creates a flow in a direction perpendicular to the axis of the nozzle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-104364 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional liquid ejection heads, there was a problem in that the length of the return throttle passage (referred to as the second section in the document) connected to the downstream side of the first section could not be sufficiently secured, which meant that the necessary pressure loss could not be secured, and there was a risk that the pressure during ejection could not be effectively applied to the nozzle.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a liquid ejection head that can easily ensure the necessary pressure loss. [Means for solving the problem]

[0006] The liquid ejection head of the present invention comprises a supply manifold to which liquid is supplied from the outside, a return manifold from which the liquid is discharged to the outside, and a plurality of individual flow paths, each of which has an upstream end connected to the supply manifold and a downstream end connected to the return manifold, and which individually connects to a plurality of nozzles arranged in a row on a nozzle face, wherein each of the plurality of individual flow paths includes a pressure chamber, a descender connected to the pressure chamber, a return throttling path connected to the return manifold, and an intervening flow path interposed between the return throttling path and the descender and connected to the nozzle, wherein the return throttling path extends in a second direction different from a first direction in which the intervening flow path extends, and the flow path cross-sectional area of ​​the return throttling path is smaller than the flow path cross-sectional area of ​​the intervening flow path.

[0007] According to the present invention, since the return throttle passage extends in a second direction different from the first direction, the length of the return throttle passage can be secured more than in the conventional embodiment in which the return throttle passage extends in the same direction as the extension direction of the intermediate passage. Also, bending loss can be generated at the connection portion between the intermediate passage and the return throttle passage. Furthermore, the flow path cross-sectional area of ​​the return throttle passage is smaller than the flow path cross-sectional area of ​​the intermediate passage. These make it easier to secure the necessary pressure loss. Effect of the Invention

[0008] According to the present invention, it is possible to provide a liquid ejection head that makes it easy to ensure the necessary pressure loss. [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 a first embodiment. [Diagram 2] 2 is a cross-sectional view of the liquid ejection head of FIG. 1 taken along a line perpendicular to the extending direction. [Diagram 3] 1A is a plan view showing an intervening passage, a return throttle passage, and a return manifold, and FIG. 1B is an enlarged plan view of the intervening passage of FIG. [Figure 4] FIG. 1A is a diagram showing a cross section of an intervening flow passage, and FIG. 1B is a diagram showing a cross section of a flow passage of a return throttle passage. [Diagram 5] FIG. 4 is a diagram for explaining dimensions of an intervening passage, a nozzle, and a return throttle passage. [Figure 6] FIG. 13 is a plan view showing a modified example of the feedback throttle path. 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] <Configuration of Liquid Ejection Apparatus> A liquid ejection device 10 including a liquid ejection head 20 according to this embodiment ejects liquid such as ink. In the following, an example in which the liquid ejection device 10 is applied to an inkjet printer will be described, but the application of the liquid ejection device 10 is not limited to this.

[0012] 1, the liquid ejection device 10 employs, for example, a line head system and includes a platen 11, a conveying unit, a head unit 16, and a tank 12. However, the liquid ejection device 10 is not limited to the line head system, and may employ other systems, such as a serial head system.

[0013] The platen 11 is a flat member, and paper 14 is placed on the upper surface of the platen 11, which plays a role in determining the distance between the paper 14 and the head unit 16. The side of the platen 11 facing the head unit 16 is referred to as the upper side, and the opposite side is referred to as the lower side, but the arrangement of the liquid ejection device 10 is not limited to this.

[0014] The transport section has, for example, two transport rollers 15 and a transport motor (not shown). The two transport rollers 15 are connected to the transport motor and are arranged parallel to each other along a direction perpendicular to the transport direction of the paper 14 (the perpendicular direction) with the platen 11 sandwiched between them. When the transport motor is driven, the transport rollers 15 rotate, and the paper 14 on the platen 11 is transported in the transport direction.

[0015] The head unit 16 has a length in the orthogonal direction that is equal to or greater than the length of the paper 14. The head unit 16 is provided with a plurality of liquid ejection heads 20.

[0016] The liquid ejection head 20 has a laminate of a flow path forming body and a volume changing section. The flow path forming body has a liquid flow path formed therein, and a plurality of nozzle holes 21a are opened in an ejection surface (nozzle surface) 40a. The volume changing section is driven to change the volume of the liquid flow path. In this case, the meniscus vibrates in the nozzle holes 21a, and liquid is ejected. Details of the liquid ejection head 20 will be described later.

[0017] When the liquid is, for example, ink, a tank 12 is provided for each type of ink. For example, four tanks 12 are provided, and black, yellow, cyan, and magenta ink are stored in each of the four tanks 12. The ink in the tanks 12 is supplied to the corresponding nozzle holes 21a.

[0018] <Configuration of Liquid Ejection Head> As described above, the liquid ejection head 20 includes a flow path forming body and a volume changing portion. As shown in FIG. 2, the flow path forming body is a laminate of a plurality of plates, and the volume changing portion includes a vibration plate 55 and a piezoelectric element 60.

[0019] The multiple plates are etched plates made of metal, and include a nozzle plate 40, a first flow path plate 41, a second flow path plate 42, a third flow path plate 43, a fourth flow path plate 44, a fifth flow path plate 45, a sixth flow path plate 46, a seventh flow path plate 47, an eighth flow path plate 48, a ninth flow path plate 49, a tenth flow path plate 50, an eleventh flow path plate 51, a twelfth flow path plate 52, a thirteenth flow path plate 53, and a fourteenth flow path plate 54. These plates are stacked in this order.

[0020] Each plate has holes and grooves of various sizes formed therein. Inside the flow path forming body in which the plates are stacked, the holes and grooves are combined to form a plurality of nozzles 21, a plurality of individual flow paths 64, a supply manifold 22, and a return manifold 23 as liquid flow paths.

[0021] The nozzles 21 are formed penetrating the nozzle plate 40 in the stacking direction (vertical direction). A plurality of nozzle holes 21a, which are the tips of the nozzles 21, are arranged in a row along the nozzle row (hereinafter referred to as the row direction) on the ejection surface 40a of the nozzle plate 40. The row direction is a direction perpendicular to the stacking direction and the width direction described below.

[0022] The inertance of the nozzle 21 to the liquid is smaller than the inertance of the return throttle passage 31 to the liquid. The inertance M of the flow passage to the liquid is expressed as M=ρ×L / S. In this formula for calculating the inertance M, ρ is the density of the liquid, L is the flow passage length, and S is the flow passage cross-sectional area.

[0023] The supply manifold 22 extends in the column direction and is connected to a plurality of individual flow paths 64. The return manifold 23 extends in the column direction and is connected to a plurality of individual flow paths 64. The supply manifold 22 is disposed above the return manifold 23. The supply manifold 22 communicates with a supply port 22a, and the return manifold 23 communicates with a return port (not shown).

[0024] The individual flow paths 64 are connected to the supply manifold 22 and the return manifold 23. The upstream ends of the individual flow paths 64 communicate with the supply manifold 22, and the downstream ends thereof communicate with the return manifold 23. The individual flow paths 64 also communicate with the base end of the nozzle 21 between the supply manifold 22 and the return manifold 23. The individual flow paths 64 each have a first communication hole 25, a supply throttle path 26, a second communication hole 27, a pressure chamber 28, a descender 29, an intervening flow path 80, a return throttle path 31, and a third communication hole 32, which are arranged in this order. The intervening flow path 80 in this embodiment will be described in detail later.

[0025] The lower end of first communication hole 25 is connected to the upper end of supply manifold 22, extends upward in the stacking direction from supply manifold 22, and penetrates an upper portion of twelfth flow path plate 52 in the stacking direction. First communication hole 25 is disposed to one side (the right side in FIG. 2) of the center of supply manifold 22 in the width direction.

[0026] One end of the supply throttle path 26 is connected to the upper end of the first communication hole 25. The supply throttle path 26 is formed, for example, by half etching, and is configured as a groove recessed from the lower surface of the thirteenth flow path plate 53. The lower end of the second communication hole 27 is connected to the other end of the supply throttle path 26, extends upward in the stacking direction from the supply throttle path 26, and penetrates an upper portion of the thirteenth flow path plate 53 in the stacking direction. The second communication hole 27 is disposed on the other side (left side in FIG. 2) of the center of the supply manifold 22 in the width direction.

[0027] One end of the pressure chamber 28 is connected to the upper end of the second communication hole 27. The pressure chamber 28 is formed to penetrate the fourteenth flow path plate 54 in the stacking direction.

[0028] The descender 29 penetrates the second flow path plate 42 to the thirteenth flow path plate 53 in the stacking direction, and is disposed on the other side in the width direction (left side in FIG. 2) of the supply manifold 22 and the return manifold 23. The descender 29 has an upper end connected to the other end of the pressure chamber 28, and a lower end connected to the intervening flow path 80. The cross-sectional area of ​​the descender 29 may be constant or may vary in the stacking direction.

[0029] The intervening flow passage 80 penetrates the first flow passage plate 41 in the stacking direction, and is disposed below the descender 29. The intervening flow passage 80 is interposed between the descender 29 and the return throttle passage 31. The intervening flow passage 80 will be described in detail later.

[0030] One end of the feedback throttle path 31 is connected to the downstream end of the second portion 80b of the intervening flow path 80. The feedback throttle path 31 is formed by, for example, half-etching processing, and is configured as a groove recessed from the lower surface of the first flow path plate 41.

[0031] The third communication hole 32 has a lower end connected to the other end of the return throttle path 31, extends upward in the stacking direction from the return throttle path 31, and penetrates an upper portion of the first flow path plate 41 in the stacking direction. The third communication hole 32 has an upper end connected to the lower end of the return manifold 23. The third communication hole 32 is disposed on the other side (the left side in FIG. 2) of the center of the return manifold 23 in the width direction.

[0032] The vibration plate 55 is laminated on the fourteenth flow path plate 54, and covers the upper end openings of the pressure chambers 28. The vibration plate 55 may be formed integrally with the fourteenth flow path plate 54. In this case, the pressure chambers 28 are formed recessed from the lower surface of the fourteenth flow path plate 54 in the lamination direction. In this fourteenth flow path plate 54, the portion above the pressure chambers 28 functions as the vibration plate 55.

[0033] The piezoelectric element 60 includes a common electrode 61, a piezoelectric layer 62, and an individual electrode 63, which are arranged in this order. The common electrode 61 covers the entire surface of the vibration plate 55 via the insulating film 56. The piezoelectric layer 62 covers the entire surface of the vibration plate 55 via the insulating film 56 and the common electrode 61. The individual electrodes 63 are provided for each pressure chamber 28, and are arranged on the piezoelectric layer 62. In this case, one piezoelectric element 60 is composed of one individual electrode 63, the common electrode 61, and a portion of the piezoelectric layer 62 sandwiched between the two electrodes.

[0034] The individual electrodes 63 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 apply it to the individual electrodes 63. In contrast, the common electrode 61 is always held at ground potential.

[0035] The active portion of the piezoelectric layer 62 expands and contracts in the planar direction together with the two electrodes 61, 63 in response to the drive signal. In response to this, the vibration plate 55 deforms in cooperation with the electrodes 61, 63, and changes in the direction of increasing or decreasing the volume of the pressure chamber 28. As a result, an ejection pressure for ejecting liquid from the nozzle 21 is applied to the pressure chamber 28 in accordance with the volume of the pressure chamber 28.

[0036] <Liquid flow> The flow of liquid in the liquid ejection head 20 of this embodiment will be described. The supply port 22a is connected to the tank 12 via a supply pipe, and the return port (not shown) is connected to the tank 12 via a return pipe. In this configuration, when the pump of the supply pipe and the negative pressure pump of the return pipe are driven, the liquid flows from the tank 12 into the supply manifold 22 via the supply port 22a.

[0037] During this time, a portion of the liquid flows into the individual flow paths 64. The liquid flows from the supply manifold 22 through the first communication hole 25 into the supply throttle path 26, and from the supply throttle path 26 through the second communication hole 27 into the pressure chamber 28. The liquid then flows through the descender 29 in the stacking direction from the upper end to the lower end, and flows into the nozzle 21 through the intervening flow path 80. When an ejection pressure is applied to the pressure chamber 28 by the piezoelectric element 60, the liquid is ejected from the nozzle hole 21a.

[0038] A portion of the liquid that is not ejected from the nozzle holes 21a flows through the return throttle passage 31 via the intervening flow passage 80, and flows into the return manifold 23 via the third communication hole 32. The liquid that has flowed into the return manifold 23 via the third communication hole 32 flows inside the return manifold 23, and circulates back to the supply port 22a from the return port via a sub-tank provided in the liquid ejection head 20.

[0039] <Details of the intervening passage and the return restriction passage> 3(a) is a plan view showing the intervening flow passage 80, the return throttle passage 31, and the return manifold 23, and FIG. 3(b) is an enlarged plan view of the intervening flow passage 80 in FIG. 3(a). As shown in FIG. 3(a), in this embodiment, the return throttle passage 31 extends in a second direction different from the first direction in which the intervening flow passage 80 extends. The first direction is the same as the width direction described above. In addition, the vector relating to the second direction includes a directional component Ds that is the same as the first direction and a directional component De that is the same as the direction De in which the liquid in the return manifold 23 flows. That is, in this embodiment, the second direction is a direction that is inclined toward the downstream end of the return manifold 23 with respect to the first direction in a plan view.

[0040] The intervening passage 80 includes a first portion 80a that overlaps with the descender 29 in a plan view and a second portion 80b that does not overlap with the descender 29. In this embodiment, the volume of the first portion 80a of the intervening passage 80 is larger than the volume of the second portion 80b, but this is not limited to this, and the volume of the second portion 80b may be larger than the volume of the first portion 80a. The intervening passage 80 has a shape having long sides and short sides. The intervening passage 80 is formed, for example, in an elliptical shape in a plan view. The return throttle passage 31 is connected to the short side side of the intervening passage 80 (the short side side toward the return manifold 23). In this configuration, each nozzle 21 is arranged so as to overlap with the second portion 80b of the intervening passage 80 in a plan view. 3(b), each nozzle 21 is disposed closer to the first portion 80a with respect to half-value Dk / 2 (e.g., 50 μm) of the distance Dk (e.g., 100 μm) from the upstream end 80b1 to the downstream end 80b2 of the second portion 80b of the intervening flow passage 80. More specifically, each nozzle 21 is disposed closer to the first portion 80a such that the distance Dkc between the position of the half-value Dk / 2 and the center 21c of the nozzle 21 is, for example, 20 μm with respect to the half-value Dk / 2.

[0041] In this embodiment, the flow path cross-sectional area CS2 of the return throttle passage 31 shown in Fig. 4(b) is smaller than the flow path cross-sectional area CS1 of the intermediate flow path 80 shown in Fig. 4(a). In addition, the depth Dh2 of the return throttle passage 31 shown in Fig. 2 is smaller than the plate thickness Dh1 of the first flow path plate 41 forming the return throttle passage 31 shown in the same figure.

[0042] 5, the dimension (width) W1 (e.g., 100 μm to 200 μm) of the intervening flow path 80 in the column direction is larger than the inner diameter In (e.g., 50 to 60 μm) of the nozzle 21. The dimension (width) W2 (e.g., 80 to 90 μm) of the return throttle path 31 in the direction perpendicular to the second direction is larger than the inner diameter In of the nozzle 21.

[0043] Furthermore, the dimension W1 of the intervening flow passage 80 in the column direction is larger than the depth Dh1 (e.g., 50 μm) of the intervening flow passage 80 (in other words, the plate thickness of the first flow passage plate 41) shown in Fig. 2. Moreover, the dimension W2 of the return throttle passage 31 in the direction perpendicular to the second direction is larger than the depth Dh2 of the return throttle passage 31 shown in Fig. 2.

[0044] As described above, according to the liquid ejection head 20 of this embodiment, since the return throttle path 31 extends in the second direction different from the first direction, the length of the return throttle path 31 can be secured more than in the conventional embodiment in which the return throttle path 31 extends in the same direction as the extension direction of the intervening flow path 80. Also, bending loss can be generated at the connection portion between the intervening flow path 80 and the return throttle path 31. Furthermore, in this embodiment, the flow path cross-sectional area CS2 of the return throttle path 31 is smaller than the flow path cross-sectional area CS1 of the intervening flow path 80. As a result, it becomes easier to secure the necessary pressure loss.

[0045] In this embodiment, a vector related to the second direction, which is the extension direction of the return throttle passage 31, includes a directional component Ds that is the same as the first direction and a directional component De that is the same as the direction De in which the liquid flows in the return manifold 23. In other words, the second direction is a direction that is inclined toward the downstream end of the return manifold 23 with respect to the first direction in a plan view. This allows the liquid to flow smoothly at the outlet of the return throttle passage 31.

[0046] In this embodiment, each nozzle 21 is disposed so as to overlap the second portion 80b of the intermediate flow passage 80 in a plan view, and is disposed closer to the first portion 80a with reference to half the distance Dk / 2 from the upstream end 80b1 to the downstream end 80b2 of the second portion 80b. In this regard, when the flow rate increases, a difference in flow velocity occurs in the nozzle 21 due to the flow bending at the inlet of the return throttle passage 31, and the shape of the meniscus becomes non-uniform. Therefore, the nozzle 21 is disposed as far away from the return throttle passage 31 as possible to prevent the above problem from occurring.

[0047] Furthermore, in this embodiment, the inertance of the nozzle 21 to the liquid is smaller than the inertance of the return throttle passage 31 to the liquid. This makes it possible to avoid a decrease in the ejection energy.

[0048] In this embodiment, the dimension W1 of the intervening flow passage 80 in the column direction is larger than the inner diameter In of the nozzle 21. Also, the dimension W2 of the return throttle passage 31 in the direction perpendicular to the second direction is larger than the inner diameter In of the nozzle 21. In this regard, if the nozzle 21 is misaligned toward the return throttle passage 31, for example, and the inside of the nozzle 21 overlaps with the return throttle passage 31, there is a problem that the shape of the meniscus becomes asymmetrical when the meniscus is drawn during ejection. With this configuration, the above problem is less likely to occur even if the nozzle plate 40 in which the nozzle 21 is formed is misaligned with respect to the first flow passage plate 41.

[0049] In this embodiment, the dimension W1 of the intervening flow passage 80 in the column direction is larger than the depth Dh1 of the intervening flow passage 80. In addition, the dimension W2 of the return throttle passage 31 in the direction perpendicular to the second direction is larger than the depth Dh2 of the return throttle passage 31. This makes it easier to form the intervening flow passage 80 and the return throttle passage 31 compared to a case where each dimension of the intervening flow passage 80 and the return throttle passage 31 is smaller than the depth.

[0050] Moreover, in this embodiment, the return throttle passage 31 is connected to the short side of the intervening passage 80. This allows the flow of liquid from the intervening passage 80 to be transmitted to the return throttle passage 31 smoothly.

[0051] Furthermore, in this embodiment, the depth Dh2 of the feedback throttle passage 31 is smaller than the plate thickness Dh1 of the first flow path plate 41 that forms the feedback throttle passage 31. In this case, by forming the feedback throttle passage 31 in the lower half in the plate thickness direction of the first flow path plate 41 by half etching, it is possible to form the downstream end of the feedback throttle passage 31 so as to extend upward to the lower part of the feedback manifold 23. This makes it possible to make the flow path length of the feedback throttle passage 31 longer, thereby ensuring a larger pressure loss.

[0052] <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.

[0053] In the above embodiment, the feedback throttle passage 31 formed in a straight line has been described, but the shape of the feedback throttle passage 31 is not limited to this, and the feedback throttle passage 31 may be formed as follows. FIG. 6 is a plan view showing a feedback throttle passage 131 according to a modified example. As shown in FIG. 6, the feedback throttle passage 131 may be bent. In detail, the feedback throttle passage 131 includes a first portion 131a extending in the same direction as the second direction in which the feedback throttle passage 31 in the above embodiment extends, and a second portion 131b connected to the first portion 131a and extending in a third direction. The third direction is a direction that is more inclined toward the downstream end of the feedback manifold 23 with respect to the first direction in a plan view than the second direction. By bending the feedback throttle passage 131 in this way, a larger pressure loss can be ensured. Note that, in FIG. 6, the feedback throttle passage 131 has one bending point, but this is not limited to this, and a feedback throttle passage having two or more bending points may be adopted.

[0054] In the above embodiment, each nozzle 21 is arranged so as to overlap the second portion 80b of the intervening flow passage 80 in a plan view and is arranged closer to the first portion 80a with respect to the half value Dk / 2 of the distance Dk from the upstream end 80b1 to the downstream end 80b2 of the second portion 80b as a reference, but this is not limited thereto. Each nozzle 21 may be arranged closer to the second portion 80b.

[0055] Furthermore, in the above embodiment, the feedback throttle passage 31 is formed in the lower half of the first flow path plate 41 in the plate thickness direction by half etching, but this is not limited to this. The feedback throttle passage 31 may be formed over the entire plate thickness direction of the first flow path plate 41. [Explanation of symbols]

[0056] 10 Liquid dispensing device 20 Liquid ejection head 21 Nozzle 22 Supply Manifold 23 Feedback manifold 28 Pressure Chamber 29 Descendant 31 Feedback throttle 40a Nozzle surface 64 Individual Channels 80 Intervening channel 80a Part 1 80b Part 2 80b1 upstream end of second section 80b2 downstream end of second section CS1 Cross-sectional area of ​​the intervening channel CS2 Return restriction flow passage cross-sectional area De,Ds direction component Dh1 Depth of the intervening channel (thickness of the first channel plate) Dh2 Depth of feedback throttle Dk Distance from the upstream end to the downstream end of the second section In Nozzle inner diameter W1: Dimension (width) of the intervening channel in the row direction W2: Dimension (width) of the feedback throttle passage in the direction perpendicular to the second direction

Claims

1. a supply manifold to which liquid is supplied from an external source; a return manifold through which the liquid is discharged to the outside; a plurality of individual flow paths each having an upstream end in communication with the supply manifold and a downstream end in communication with the return manifold, the individual flow paths being individually connected to a plurality of nozzles arranged in a row on a nozzle face; One flow path is connected to the return manifold from the upstream side for each of the individual flow paths, each of the plurality of individual flow paths includes a pressure chamber, a descender communicating with the pressure chamber, a return throttle passage communicating with the return manifold, and an intervening flow path interposed between the return throttle passage and the descender, communicating with the nozzle, and not including a branch; A liquid ejection head, wherein the return throttle passage extends in a second direction different from a first direction in which the intervening flow passage extends in a plane parallel to the nozzle face, and a flow path cross-sectional area of ​​the return throttle passage is smaller than a flow path cross-sectional area of ​​the intervening flow path.

2. The liquid ejection head according to claim 1 , wherein the second direction is a direction that includes a directional component that is the same as a directional component of a vector related to a direction in which the liquid flows inside the return manifold.

3. the intervening flow passage includes a first portion that overlaps with the descender in a plan view and a second portion that does not overlap with the descender, 3. The liquid ejection head according to claim 1, wherein each of the nozzles is arranged so as to overlap the second portion in a planar view and is arranged closer to the first portion based on half the distance from the upstream end to the downstream end of the second portion.

4. 4. The liquid ejection head according to claim 1, wherein an inertance of the nozzle with respect to the liquid is smaller than an inertance of the return throttle passage with respect to the liquid.

5. A liquid ejection head according to any one of claims 1 to 4, wherein the dimension of the intervening flow path in a direction along the row is larger than the inner diameter of the nozzle, and the dimension of the return throttle path in a direction perpendicular to the second direction is larger than the inner diameter of the nozzle.

6. The liquid ejection head according to claim 1 , wherein the feedback throttle path is bent.

7. A liquid ejection head as described in any one of claims 1 to 6, wherein the dimension of the intervening flow path in a direction along the row is greater than the depth of the intervening flow path, and the dimension of the return throttle path in a direction perpendicular to the second direction is greater than the depth of the return throttle path.

8. the interstitial flow passage has a shape with a long side and a short side; The liquid ejection head according to claim 1 , wherein the feedback throttle passage is connected to a short side of the intermediate passage.

9. 9. The liquid ejection head according to claim 1, wherein the intervening flow path and the feedback throttle path are formed in the same plate, and the feedback throttle path is formed by half-etching in a lower half of the plate opposite the feedback manifold.

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