Liquid ejection head

Abstract

To provide a liquid ejection head that is able to prevent an influence on ejection characteristics even when a circulation passage connecting adjacent individual flow passages is provided.SOLUTION: A liquid ejecting head includes: a first manifold to which a liquid is supplied from outside or from which the liquid is ejected outside; a second manifold to which the liquid is ejected outside or to which the liquid is supplied from outside; a first nozzle provided on a nozzle surface and configured to eject the liquid supplied from the first manifold; a second nozzle provided on the nozzle surface and configured to eject the liquid supplied from the second manifold; a first individual flow passage that communicates between the first manifold and the first nozzle; a second individual flow passage that communicates between the second manifold and the second nozzle; and a circulation passage that communicates between the first individual flow passage and the second individual flow passage. An inertance of the first nozzle is smaller than an inertance of the circulation passage, and an inertance of the second nozzle is smaller than an inertance of the circulation passage.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] Conventionally, a liquid ejection head including a reflux path that connects one nozzle flow path, which is a communication path for a nozzle, and the other nozzle flow path adjacent to the one nozzle flow path, is known (Patent Document 1). In this liquid ejection head, since a part of the ink flows from one nozzle flow path to the other nozzle flow path through the reflux path, bubbles are discharged by this flow.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a conventional liquid ejection head, depending on the parameters of the flow path including the nozzle, the pressure chamber, and the descender, the pressure generated in the pressure chamber may not be fully transmitted to the nozzle, and there is a risk that the ink may not be ejected well. Therefore, it is an issue to suppress the influence on the ejection characteristics.

[0005] Therefore, an object of the present disclosure is to provide a liquid ejection head capable of suppressing the influence on ejection characteristics even when a circulation path connecting adjacent individual flow paths is provided.

Means for Solving the Problems

[0006] The liquid ejection head of the present disclosure includes a first manifold through which liquid is supplied from the outside or the liquid is discharged to the outside, a second manifold through which the liquid is discharged to the outside or the liquid is supplied from the outside, a circulation path communicating with the first manifold and the second manifold, a plurality of first individual flow paths each having one end communicating with the first manifold, the other end communicating with the circulation path, and being individually communicated with a plurality of first nozzles arranged in a row on a nozzle surface, and a plurality of second individual flow paths each having one end communicating with the circulation path, the other end communicating with the second manifold, and being individually communicated with a plurality of second nozzles arranged in a row on the nozzle surface. The inertia of the first nozzle is smaller than the inertia of the circulation path, and the inertia of the second nozzle is smaller than the inertia of the circulation path.

[0007] According to the present disclosure, since the inertia of the first nozzle is smaller than the inertia of the circulation path, the pressure generated in the pressure chamber included in the first individual flow path is difficult to be transmitted to the circulation path. Thereby, it is possible to suppress the influence on the ejection characteristics of the first nozzle and suppress the influence (crosstalk) on the ejection characteristics of the second nozzle adjacent to the first nozzle. Further, since the inertia of the second nozzle is smaller than the inertia of the circulation path, the pressure generated in the pressure chamber included in the second individual flow path is difficult to be transmitted to the circulation path. Thereby, it is possible to suppress the influence on the ejection characteristics of the second nozzle and suppress the influence (crosstalk) on the ejection characteristics of the first nozzle adjacent to the second nozzle.

Advantages of the Invention

[0008] According to the present disclosure, it is possible to provide a liquid ejection head capable of suppressing the influence on ejection characteristics even when a circulation path connecting adjacent individual flow paths is provided.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0010] Hereinafter, the liquid ejection head according to the embodiment of the present disclosure will be described with reference to the drawings. The liquid ejection head described below is only one embodiment of the present disclosure. Therefore, the present disclosure is not limited to the following embodiments, and additions, deletions, and changes are possible without departing from the spirit of the present disclosure.

[0011] <Configuration of Liquid Ejection Device> The liquid ejection device 10 including the liquid ejection head 20 according to the present embodiment ejects a liquid such as ink. Hereinafter, an example in which the liquid ejection device 10 is applied to an inkjet printer will be described, but the application target of the liquid ejection device 10 is not limited to this.

[0012] As shown in FIG. 1, the liquid ejection device 10 employs, for example, a line head system, and includes a platen 11, a conveyance unit described later, a head unit 16, and a tank 12.

[0013] The platen 11 is a flat plate member, and has a role of arranging the paper 14 on its upper surface and determining the distance between the paper 14 and the head unit 16. Note that the side closer to the head unit 16 than the platen 11 is referred to as the upper side, and the opposite side is referred to as the lower side, but the direction in the liquid ejection device 10 is not limited to this.

[0014] The conveying unit has, for example, two conveying rollers 15 and a conveying motor (not shown). The two conveying rollers 15 are connected to the conveying motor and are arranged parallel to each other along a direction (orthogonal direction) orthogonal to the conveying direction of the sheet 14 with the platen 11 sandwiched therebetween. When the conveying motor is driven, the conveying rollers 15 rotate and the sheet 14 on the platen 11 is conveyed in the conveying direction.

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

[0016] The liquid ejection head 20 has a laminate of a flow path forming body and a volume changing unit. The flow path forming body has liquid flow paths formed therein, and a plurality of nozzle holes 24, 24A (described later) open on a discharge surface (nozzle surface) 40a. The volume changing unit is driven to change the volume of the liquid flow path. In this case, at the nozzle holes 24, 24A, the meniscus vibrates and the liquid is ejected. The detailed configuration of the liquid ejection head 20 will be described later.

[0017] When the liquid is, for example, ink, the tanks 12 are provided for each type of the ink. For example, four tanks 12 are provided, and black, yellow, cyan, and magenta inks are respectively stored in the four tanks 12. The ink in the tanks 12 is supplied to the corresponding nozzle holes 24, 24A.

[0018] <Configuration of Liquid Ejection Head> The liquid ejection head 20 includes the flow path forming body and the volume changing unit as described above. As shown in FIG. 2, the above flow path forming body is a laminate of a plurality of plates, and the above volume changing unit has a diaphragm 48 and piezoelectric elements 60, 60A.

[0019] The plurality of plates described above are, for example, metal etching plates, and include a nozzle plate 40, a first flow path plate (hereinafter referred to as a return 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, and a seventh flow path plate 47. These plates are laminated in this order. The nozzle plate 40 and the return plate 41 are adjacent to each other in the thickness direction.

[0020] Various holes and grooves of different sizes are formed in each plate. Inside the flow path forming body in which each plate is laminated, the holes and grooves are combined to form a plurality of nozzles 21, 21A, a plurality of individual flow paths 64, 64A, a first manifold 22, and a second manifold 22A as liquid flow paths. The nozzle 21 corresponds to the first manifold 22, and the nozzle 21A corresponds to the second manifold 22A. The nozzles 21, 21A are formed by the nozzle plate 40 being penetrated in the lamination direction (vertical direction). On the discharge surface 40a of the nozzle plate 40, a plurality of nozzle holes 24, 24A, which are the tips of the nozzles 21, 21A, are arranged side by side in the direction along the nozzle row (hereinafter referred to as the row direction). The row direction is a direction orthogonal to the above-mentioned lamination direction and the width direction described later. Note that the nozzle 21A corresponds to the first nozzle, the nozzle 21 corresponds to the second nozzle, the individual flow path 64A corresponds to the first individual flow path, and the individual flow path 64 corresponds to the second individual flow path.

[0021] The liquid ejection head 20 has a plurality of configurations in the width direction such that the first manifold 22, the nozzle 21, and the flow path between the first manifold 22 and the nozzle 21 are provided symmetrically in the width direction with respect to the second manifold 22A, the nozzle 21A, and the flow path between the second manifold 22A and the nozzle 21A. Each configuration of the first manifold 22, the nozzle 21, and the flow path between the first manifold 22 and the nozzle 21 is the same as each configuration of the second manifold 22A, the nozzle 21A, and the flow path between the second manifold 22A and the nozzle 21A. And, for ease of understanding, the reference numerals assigned to the components of the flow path between the second manifold 22A and the nozzle 21A, including the second manifold 22A and the nozzle 21A, are the same as those assigned to the components of the flow path between the first manifold 22 and the nozzle 21, with A added. Hereinafter, unless otherwise noted, the second manifold 22A, the nozzle 21A, and the flow path between the second manifold 22A and the nozzle 21A will be described.

[0022] The second manifold 22A functions as a supply manifold or a return manifold. That is, the second manifold 22A is for liquid to be supplied from the outside or for liquid to be discharged to the outside. When liquid is supplied to the second manifold 22A, the nozzle 21A ejects the liquid supplied from the second manifold 22A.

[0023] The first manifold 22 functions as a return manifold when the second manifold 22A functions as a supply manifold. The first manifold 22 functions as a supply manifold when the second manifold 22A functions as a return manifold. That is, the first manifold 22 is for liquid to be discharged to the outside or for liquid to be supplied from the outside. When liquid is supplied to the first manifold 22, the nozzle 21 ejects the liquid supplied from the first manifold 22.

[0024] Hereinafter, a representative aspect will be described in which, with respect to the flow of the liquid, the second manifold 22A functions as a supply manifold and the first manifold 22 functions as a return manifold. Note that an aspect in which the second manifold 22A functions as a return manifold and the first manifold 22 functions as a supply manifold is the same as the above aspect, and thus the description thereof will be omitted.

[0025] The second manifold 22A extends in the column direction and is connected to a plurality of individual flow paths 64A. Similarly, the first manifold 22 extends in the column direction and is connected to a plurality of individual flow paths 64. The second manifold 22A communicates with a port (a port that can be switched between a supply port and a return port), not shown, and the first manifold 22 communicates with a port (a port that can be switched between a return port and a supply port), not shown.

[0026] The plurality of individual flow paths 64A are connected to the second manifold 22A. One end of the individual flow path 64A communicates with the second manifold 22A, and the other end of the individual flow path 64A communicates with the nozzle 21A. Further, the individual flow path 64A communicates with an adjacent individual flow path 64 in the width direction via a circulation path 30 formed in the return plate 41. The depth of the circulation path 30 is, for example, the same as the thickness of the return plate 41.

[0027] The individual flow path 64A has a communication hole 25A, a throttle path 26A, a communication hole 27A, a pressure chamber 28A, and a descender 29A, which are arranged in this order. Note that the pressure chamber 28A corresponds to the first pressure chamber, the pressure chamber 28 included in the individual flow path 64 corresponds to the second pressure chamber, the descender 29A corresponds to the first descender, and the descender 29 included in the individual flow path 64 corresponds to the second descender.

[0028] The communication hole 25A is formed such that its lower end is connected to the upper end of the second manifold 22A, extends upward from the second manifold 22A, and penetrates the upper portion of the fifth flow path plate 45 in the stacking direction. The communication hole 25A is arranged on one side (the left side in FIG. 2) of the second manifold 22A rather than at the center in the width direction.

[0029] One end of the throttle passage 26A is connected to the upper end of the communication hole 25A. The throttle passage 26A is formed, for example, by half-etching, and is constituted by a groove recessed upward from the lower surface of the sixth flow path plate 46. The communication hole 27A has its lower end connected to the other end of the throttle passage 26A, extends upward in the stacking direction from the throttle passage 26A, and is formed by penetrating the upper portion of the sixth flow path plate 53 in the stacking direction.

[0030] One end of the pressure chamber 28A is connected to the upper end of the communication hole 27A. The pressure chamber 28A is formed by penetrating the seventh flow path plate 47 in the stacking direction.

[0031] The descender 29A is formed by penetrating the return plate 41 to the sixth flow path plate 46 in the stacking direction. The descender 29A is arranged on the other side (the right side in FIG. 2) of the second manifold 22A in the width direction. The upper end of the descender 29A is connected to the other end of the pressure chamber 28A, and the lower end thereof is connected to the nozzle 21A. Further, the descender 29A communicates with the descender 29 of the individual flow paths 64 adjacent in the width direction via the circulation path 30 formed in the return plate 41.

[0032] The pressure chamber 28A is connected to the pressure chambers 28 of the individual flow paths 64 adjacent in the width direction via the connection path 31 formed in the seventh flow path plate 47. The connection path 31 is provided above the circulation path 30. In this embodiment, the connection path 31 is not an essential component. That is, the pressure chamber 28A and the pressure chamber 28 may not communicate with each other in the seventh flow path plate 47.

[0033] On the return plate 41, for example, a thin-walled portion forming a damper portion is formed by recessing from the surface on the nozzle plate 40 side in the thickness direction of the return plate 41 by half-etching. Thereby, a damper space 23A corresponding to the second manifold 22A and a damper space 23 corresponding to the first manifold 22 are formed.

[0034] The diaphragm 48 is laminated on the seventh flow path plate 47 and covers the upper end openings of the pressure chambers 28, 28A. Note that the diaphragm 48 may be integrally formed with the seventh flow path plate 47. In this case, the pressure chambers 28, 28A are formed to be recessed upward from the lower surface of the seventh flow path plate 47 in the stacking direction. In the seventh flow path plate 47, the portion above the pressure chambers 28, 28A functions as the diaphragm 48.

[0035] The piezoelectric element 60A includes a common electrode 61, a piezoelectric layer 62, and an individual electrode 63A, which are arranged in this order. The common electrode 61 covers the entire surface of the diaphragm 48 via the insulating film 49. The piezoelectric layer 62 covers the entire surface of the diaphragm 48 via the insulating film 49 and the common electrode 61. The individual electrodes 63A are provided for each pressure chamber 28A and are arranged on the piezoelectric layer 62. In this case, one piezoelectric element 60A is constituted by one individual electrode 63A, the common electrode 61, and the piezoelectric layer 62 which is the portion sandwiched between both electrodes.

[0036] The individual electrode 63A is electrically connected to the driver IC. This driver IC receives a control signal from a control unit (not shown), generates a drive signal, and applies it to the individual electrode 63A. On the other hand, the common electrode 61 is always held at the ground potential.

[0037] The active part of the piezoelectric layer 62 expands and contracts in the plane direction together with the two electrodes 61, 63A in response to the drive signal. Accordingly, the diaphragm 48 deforms cooperatively, and changes in the direction of increasing or decreasing the volume of the pressure chamber 28A. As a result, a discharge pressure for discharging the liquid from the nozzle 21A is applied to the pressure chamber 28A according to the volume of the pressure chamber 28A. At this time, the liquid is discharged from the nozzle 21A.

[0038] In the above configuration, a schematic port communicating with the second manifold 22A is connected to the tank 12 by a schematic first pipe, and a schematic port communicating with the first manifold 22 is connected to the tank 12 by a schematic second pipe. When the pump in the first pipe and the negative pressure pump in the second pipe are driven, the liquid flows from the tank 12 into the second manifold 22A through the above ports. The liquid flows from the second manifold 22A into the throttle passage 26A through the communication hole 25A, and flows from the throttle passage 26A into the pressure chamber 28A through the communication hole 27A. Then, the liquid flows from the upper end of the descender 29A to its lower end and flows into the nozzle 21A. When a discharge pressure is applied to the pressure chamber 28A by the piezoelectric element 60A, the liquid is discharged from the nozzle hole 24A.

[0039] A part of the liquid that has not been discharged from the nozzle hole 24A flows into the individual flow path 64 through the circulation path 30. At this time, by driving the piezoelectric element 60, the liquid may or may not be discharged from the nozzle hole 24 of the nozzle 21 in the individual flow path 64. The liquid that has flowed into the individual flow path 64 flows into the first manifold 22. The liquid that has flowed into the first manifold 22 flows through the first manifold 22, returns to the port communicating with the second manifold 22A via the sub-tank provided in the liquid discharge head 20 from the port, and circulates.

[0040] Here, the inertia of the nozzle 21A is smaller than the inertia of the circulation path 30. Also, the inertia of the nozzle 21 is smaller than the inertia of the circulation path 30. For example, the inertia of the nozzles 21, 21A is 9.3×10 7 ~6.9×10 7 (unit: kg / m 4 ), and the inertia of the circulation path 30 is 2.9×10 8 ~2.3×10 8 (unit: kg / m 4 ). Note that the inertia M is expressed as M = ρ×L / S. In the calculation formula of the inertia M, ρ is the density of the liquid, L is the flow path length, and S is the flow path cross-sectional area.

[0041] The value obtained by multiplying the inertia of nozzle 21A by three is smaller than the inertia of flow path 30. Also, the value obtained by multiplying the inertia of nozzle 21 by three is smaller than the inertia of flow path 30.

[0042] The sum of the inertia of nozzle 21A and the inertia of descender 29A is smaller than the inertia of connection path 31 (first condition). Also, the sum of the inertia of nozzle 21 and the inertia of descender 29 is smaller than the inertia of connection path 31 (second condition). In the liquid discharge head 20 of the present embodiment, at least one of the first condition and the second condition is satisfied.

[0043] For example, the inertia of descenders 29 and 29A is 4.0×10 7 ~3.0×10 7 (unit: kg / m 4 ) and the inertia of connection path 31 is 3.8×10 8 ~1.1×10 9 (unit: kg / m 4 ).

[0044] The liquid discharge head 20 of FIG. 2 may be configured as follows. FIG. 3 is a cross-sectional view showing a modified example of the configuration of the liquid discharge head 20.

[0045] In the liquid discharge head 20 shown in FIG. 3, unlike the liquid discharge head 20 of FIG. 2 in which the damper spaces 23 and 23A are formed in the return plate 41, the damper spaces are not formed in the return plate 41, and a part of the second manifold 22A and a part of the first manifold 22 are formed in the return plate 41. And, unlike the liquid discharge head 20 of FIG. 2 in which the nozzle plate 40 is made of metal, in the liquid discharge head 20 of FIG. 3, the nozzle plate 40 is made of resin. The nozzle plate 40 is adjacent to both the second manifold 22A and the first manifold 22 in the thickness direction. Note that also in the aspect of FIG. 3, the connection path 31 is not an essential component. That is, the pressure chamber 28A and the pressure chamber 28 may not communicate with each other in the seventh flow path plate 47.

[0046] Next, FIG. 4 is a diagram for explaining the cross-sectional areas of the connection path 31 and the pressure chambers 28, 28A.

[0047] In FIG. 4, the cross-sectional area of the connection path 31 cut by a line segment L3 perpendicular to the liquid flow direction Df3 of the connection path 31 is smaller than the cross-sectional area of the pressure chamber 28A cut by a line segment L2 perpendicular to the liquid flow direction Df2 of the pressure chamber 28A. Further, the above cross-sectional area of the connection path 31 is smaller than the cross-sectional area of the pressure chamber 28 cut by a line segment L1 perpendicular to the liquid flow direction Df1 of the pressure chamber 28. Thereby, the pressures from both the pressure chamber 28A and the pressure chamber 28 can be directed toward the corresponding nozzles 21A, 21, respectively, so that the pressure is efficiently transmitted to the nozzles 21A, 21.

[0048] As described above, according to the liquid discharge head 20 of the present embodiment, since the inertia of the nozzle 21A is smaller than the inertia of the circulation path 30, the pressure generated in the pressure chamber 28A included in the individual flow path 64A is difficult to be transmitted to the circulation path 30. Thereby, the influence on the discharge characteristics of the nozzle 21A can be suppressed, and the influence (crosstalk) on the discharge characteristics of the nozzle 21 adjacent to the nozzle 21A in the width direction can be suppressed. Further, since the inertia of the nozzle 21 is smaller than the inertia of the circulation path 30, the pressure generated in the pressure chamber 28 included in the individual flow path 64 is difficult to be transmitted to the circulation path 30. Thereby, the influence on the discharge characteristics of the nozzle 21 can be suppressed, and the influence (crosstalk) on the discharge characteristics of the nozzle 21A adjacent to the nozzle 21 in the width direction can be suppressed.

[0049] Also, in the present embodiment, the value obtained by multiplying the inertia of the nozzle 21A by 3 is smaller than the inertia of the circulation path 30. Further, the value obtained by multiplying the inertia of the nozzle 21 by 3 is smaller than the inertia of the circulation path 30. Thereby, the influence on the discharge characteristics of the nozzle 21A and the nozzle 21 can be further suppressed.

[0050] In addition, in the present embodiment, the depth of the circulation path 30 is the same as the thickness of the return plate 41. As a result, the circulation path 30 can be formed by full etching with respect to the return plate 41, and there is no variation in the depth dimension, so that the variation in the inertia of the circulation path 30 can be reduced. Thereby, the influence on the discharge characteristics of the nozzle 21A and the discharge characteristics of the nozzle 21 can be further suppressed.

[0051] In addition, in the present embodiment, the nozzle plate 40 and the return plate 41 are adjacent to each other in the thickness direction. As a result, a circulating flow of liquid can be formed up to the vicinity of the nozzle 21A and the vicinity of the nozzle 21, so that the effect of preventing drying of these nozzles 21A and 21 can be enhanced.

[0052] In addition, in the present embodiment, the nozzle plate 40 may be made of resin, and the nozzle plate 40 is adjacent to both the second manifold 22A and the first manifold 22 in the thickness direction. As a result, since the resin-made nozzle plate 40 can serve as a damper, the pressure attenuation effect in the second manifold 22A and the first manifold 22 is higher than the case where a damper formed of a metal plate is provided. In addition, since the nozzle plate 40 also serves as a damper, there is no need to separately provide a damper. This leads to a reduction in the number of parts.

[0053] In addition, in the present embodiment, the connection path 31 is provided above the circulation path 30. As a result, the air accumulated in the supply-side pressure chamber among the pressure chamber 28A and the pressure chamber 28 flows into the return-side pressure chamber via the connection path 31. Thereby, the air can be effectively discharged.

[0054] Furthermore, in the present embodiment, the sum of the inertance of the nozzle 21A and the inertance of the descender 29A is smaller than the inertance of the connection path 31 (first condition). Also, the sum of the inertance of the nozzle 21 and the inertance of the descender 29 is smaller than the inertance of the connection path 31 (second condition). In the liquid ejection head 20, at least one of the first condition and the second condition is satisfied. Thereby, the pressures from both the pressure chamber 28A and the pressure chamber 28 can be directed toward the corresponding nozzles 21A and 21, respectively, so that the pressure is efficiently transmitted to the nozzles 21A and 21.

[0055] The present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present disclosure. For example, it is as follows.

[0056] In the above embodiment, the line head type liquid ejection device 10 is adopted, but it is not limited thereto, and other types such as the serial head type may be used.

[0057] Also, in the above embodiment, the paper 14 is used as the printing medium, but it is not limited thereto, and printing may be performed on other printing media such as cloth, for example.

[0058] Furthermore, in the above embodiment, the number of plates constituting the flow path forming body of the liquid ejection head 20 is not limited to the above, and can be set as appropriate.

Description of Reference Numerals

[0059] 20 Liquid ejection head 21, 21A Nozzles 22 First manifold 22A Second manifold 28, 28A Pressure chambers 29, 29A Descenders 30 Circulation path 31 Connection path 40 Nozzle plate 40a Ejection surface 41 Return plate 64,64A individual flow paths Flow directions of the liquid in the pressure chambers Df1 and Df2 Flow direction of the liquid in the connection path Df3

Claims

1. A first manifold through which a liquid is supplied from the outside or the liquid is discharged to the outside, a second manifold through which the liquid is discharged to the outside or the liquid is supplied from the outside, a first nozzle provided on a nozzle surface for discharging the liquid supplied from the first manifold, a second nozzle provided on the nozzle surface for discharging the liquid supplied from the second manifold, a first individual flow path communicating between the first manifold and the first nozzle, a second individual flow path communicating between the second manifold and the second nozzle, and a circulation path communicating between the first individual flow path and the second individual flow path, wherein an inertia of the first nozzle is smaller than an inertia of the circulation path, and an inertia of the second nozzle is smaller than an inertia of the circulation path. A liquid discharge head.

2. A value obtained by multiplying the inertia of the first nozzle by three is smaller than the inertia of the circulation path, and a value obtained by multiplying the inertia of the second nozzle by three is smaller than the inertia of the circulation path. The liquid discharge head according to claim 1.

3. Comprising a return plate in which the circulation path is formed, wherein a depth of the circulation path is the same as a thickness of the return plate. The liquid discharge head according to claim 1.

4. Comprising a nozzle plate in which the first nozzle and the second nozzle are formed, wherein the nozzle plate and the return plate are adjacent to each other in a thickness direction. The liquid discharge head according to claim 3.

5. The nozzle plate is made of resin and is adjacent to both the first manifold and the second manifold in a thickness direction. The liquid discharge head according to claim 4.

6. The first individual flow path includes a first pressure chamber, the second individual flow path includes a second pressure chamber, and a connection path connecting the first pressure chamber and the second pressure chamber, wherein the connection path is provided above the circulation path. The liquid discharge head according to claim 1.

7. A cross-sectional area intersecting a liquid flow direction of the connection path is smaller than a cross-sectional area intersecting a liquid flow direction of the first pressure chamber and a cross-sectional area intersecting a liquid flow direction of the second pressure chamber. The liquid discharge head according to claim 6.

8. The first individual flow path includes a first descender having one end communicating with the corresponding first pressure chamber and the other end communicating with the corresponding first nozzle, The second individual flow path includes a second descender having one end communicating with the corresponding second pressure chamber and the other end communicating with the corresponding second nozzle. The liquid discharge head according to claim 6, wherein any one of a first condition that a combined value of an inertia of the first nozzle and an inertia of the first descender is smaller than an inertia of the connection path, a second condition that a combined value of an inertia of the second nozzle and an inertia of the second descender is smaller than an inertia of the connection path, and the first condition and the second condition is satisfied.

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