Head module, liquid ejection head, and liquid ejection device

Abstract

To provide a head module, a liquid ejection head, and a device for ejecting a liquid, which prevent an adhesive from being extruded to an ejection surface.SOLUTION: A head module 100 includes: a head 1 including a nozzle plate 10 on which a nozzle 11 for ejecting liquid is formed, and a channel substrate 20 forming an individual channel 40 communicating with the nozzle 11; and a cover member 103 covering at least one side of an ejection surface 10a of the nozzle plate 10 of the head 1. An outer shape of the nozzle plate 10 is smaller than an outer shape of the channel substrate 20. In a bonding surface 20a of the channel substrate 20 which bonding surface is on a side of the nozzle plate 10, the cover member 103 is bonded to an outer area of the nozzle plate 10 by means of an adhesive 300. The ejection surface 10a of the nozzle plate 10 is liquid-repellent, and respective bonding surfaces 20a, 103a of the channel substrate 20 and the cover member 103 with the adhesive 300 are lyophilic.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a head module, a liquid ejection head, and an apparatus for ejecting liquid. [Background technology]

[0002] 2. Description of the Related Art Some liquid ejection heads or head modules that eject liquid are provided with a cover member that covers the periphery of a nozzle surface on which nozzles are formed.

[0003] Conventionally, a flow path substrate and a cover member are bonded together with an adhesive (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-093516 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, in a configuration in which the flow path substrate and the cover member are bonded with an adhesive, there is a problem in that the adhesive must be prevented from spilling onto the nozzle plate surface (ejection surface).In addition, when a room temperature curing adhesive is used, there is a problem in that the occurrence of leaks due to flow (outflow) during curing must be prevented.

[0006] The present invention has been made in view of the above-mentioned problems, and has an object to suppress leakage due to the adhesive overflowing onto the ejection surface and the adhesive flowing out. [Means for solving the problem]

[0007] In order to solve the above problems, a head module according to the present invention comprises: a nozzle plate in which nozzles for ejecting liquid are formed; a head including a flow path substrate that forms individual flow paths that communicate with the nozzles; a cover member that covers at least one side of the ejection surface of the nozzle plate of the head, the nozzle plate has an outer shape smaller than the outer shape of the flow path substrate; At least the cover member is bonded to an outer region of the nozzle plate on a surface of the flow path substrate facing the nozzle plate with an adhesive; the ejection surface of the nozzle plate is liquid-repellent; The surfaces of the flow path substrate and the cover member joined by the adhesive are lyophilic. death, The cover member is also joined to a member disposed with a space therebetween on the side wall surface of the flow path substrate. , an electric member connected to a driving means for pressurizing the liquid in the individual flow path; the electrical member includes a portion disposed in the space, The portion of the electrical member disposed in the space A fluororesin is applied to the surface facing the cover member. The composition was as follows. [Effects of the Invention]

[0008] According to the present invention, it is possible to suppress leakage due to the adhesive overflowing onto the ejection surface and the adhesive flowing out. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is an exploded perspective view illustrating a head module according to a first embodiment of the present invention. [Figure 2] 10 is a cross-sectional explanatory view of one head of the head module taken along the short side of the head. FIG. [Figure 3] FIG. 4 is an explanatory plan view of two head portions for explaining joining of the cover member in the first embodiment. [Figure 4] FIG. 4 is an explanatory cross-sectional view of a main part taken along line AA in FIG. 3. [Figure 5] FIG. 10 is an illustrative side view of a liquid ejection head according to a second embodiment of the present invention. [Figure 6] FIG. 11 is an explanatory plan view of a discharge surface portion of one head in a different example of the third embodiment of the present invention. [Figure 7]1 is a schematic explanatory diagram of an example of a liquid ejection device according to the present invention. [Figure 8] FIG. 2 is a plan view illustrating an example of a head unit of the device. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. A head module according to a first embodiment of the present invention will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is an exploded perspective view of the head module according to the embodiment, and Fig. 2 is a cross-sectional view of one head portion of the head module taken along the short side of the head.

[0011] The head module 100 includes a plurality of heads 1 that eject liquid, a base member 102, a cover member 103, a heat dissipation member 104, a manifold 105, a printed circuit board (PCB) 106, and a module case 107.

[0012] The head 1 comprises a nozzle plate 10 in which nozzles 11 are formed, a flow path substrate 20 in which individual flow paths such as pressure chambers 21 communicating with the nozzles 11 are formed, and a vibration plate 30 including piezoelectric elements 40 that serve as driving means for pressurizing the liquid in the pressure chambers 21. The head 1 also comprises an intermediate flow path plate 50 laminated on the vibration plate 30, and a common flow path member 70 laminated on the intermediate flow path plate 50. The common flow path member 70 forms a frame member for one head 1.

[0013] The flow path substrate 20 forms the pressure chambers 21 , as well as individual supply flow paths 22 communicating with the pressure chambers 21 and individual recovery flow paths 24 communicating with the pressure chambers 21 .

[0014] The intermediate flow path plate 50 forms an intermediate supply flow path 51 that communicates with the individual supply flow path 22 through the opening 31 of the vibration plate 30, and an intermediate recovery flow path 52 that communicates with the individual recovery flow path 24 through the opening 32 of the vibration plate 30.

[0015] The common flow path member 70 forms a common supply flow path 71 that communicates with the intermediate supply flow path 51, and a common recovery flow path 72 that communicates with the intermediate recovery flow path 52. The common supply flow path 71 communicates with the supply port 81 via a flow path 151 of the manifold 105. The common recovery flow path 72 communicates with the recovery port 82 via a flow path 152 of the manifold 105.

[0016] The printed circuit board 106 and the piezoelectric element 40 of the head 1 are connected via a flexible wiring member 90, on which a driver IC (drive circuit) 91 is mounted.

[0017] The heads 1 are inserted into openings 121 of a base member 102, and a cover member 103 bonded and fixed to the base member 102 is bonded and fixed to a flow path substrate 20 of the head 1 with an adhesive.

[0018] The cover member 103 has openings corresponding to the areas of the nozzles 11 of the nozzle plate 10, and the cover member 103 covers the peripheral edge of the nozzle plate 10 of the head 1. Note that the present invention is applicable as long as the cover member 103 covers the edge of at least one side of the nozzle plate 10.

[0019] The base member 102 is a member that is disposed on the side wall surface of the flow path substrate 20 with a space 150 therebetween, and a part of the flexible wiring member 90 is disposed within the space 150 .

[0020] In addition, in the longitudinal direction of the head 1, a flange portion provided on the outside of the common flow path member 70 is joined and fixed to the base member 102.

[0021] Next, joining of the cover members in the first embodiment will be described with reference to Figures 3 and 4. Figure 3 is a plan view of two head portions used in the description, and Figure 4 is a cross-sectional view of the main parts taken along line AA in Figure 3.

[0022] The outer shape of the nozzle plate 10 of the head 1 is smaller than the outer shape of the flow path substrate 20 in plan view. The cover member 103 has a bonding surface 103a bonded to a bonding surface 20a, which is an outer region of the nozzle plate 10, on the surface of the flow path substrate 20 facing the nozzle plate 10, with an adhesive 300. In this embodiment, the bonding surface 103a of the cover member 103 bonded to the bonding surface 20a of the flow path substrate 20 is located closer to the flow path substrate 20 than the ejection surface 10a of the nozzle plate 10.

[0023] The cover member 103 is provided with a step portion 103b on the side facing the flow path substrate 20. The step portion 103b is composed of a bonding surface 103a with the flow path substrate 20, an opposing surface 103e of a portion 103c facing the peripheral edge of the ejection surface 10a of the nozzle plate 10, and a surface 103f connecting the bonding surface 103a and the opposing surface 103e.

[0024] Due to this step portion 103b, the thickness of a portion 103c of the cover member 103 facing the peripheral edge of the ejection surface 10a of the nozzle plate 10 is thinner than the thickness of a portion 103d that is joined to the flow path substrate 20, and the portion 103c facing the peripheral edge of the ejection surface 10a of the nozzle plate 10 has an eave shape. The step portion 103b can also be made into an inclined portion.

[0025] Here, the liquid repellency (water repellency) and liquid affinity (hydrophilicity) of each surface of the nozzle plate 10, the flow path substrate 20, the cover member 103, etc. will be described.

[0026] The surface of the nozzle plate 10 is liquid-repellent because a liquid-repellent film or the like is formed thereon.

[0027] The respective bonding surfaces 20a, 103a of the flow path substrate 20 and the cover member 103 have lyophilicity.

[0028] The cover member 103 has a facing surface 103e of the canopy-shaped portion 103c facing the nozzle plate 10, which is lyophilic.

[0029] The cover member 103 has a surface 103g opposite to a bonding surface 103a that is bonded to the flow path substrate 20, which is liquid repellent.

[0030] With this configuration, the adhesive 300 that bonds the flow path substrate 20 and the cover member 103 is more likely to remain on the liquid-philic bonding surfaces 20a, 103a, and migration to the ejection surface 10a of the liquid-repellent nozzle plate 10 is suppressed.

[0031] This makes it possible to prevent the adhesive 300 from spilling onto the surface (ejection surface) of the nozzle plate 10.

[0032] The specific details will be explained below.

[0033] The periphery of the cover member 103 and the flow path substrate 20 is bonded with an adhesive 300 to prevent liquid from entering from the outside. In addition, the cover member 103 is also bonded with an adhesive to the base member 102 to protect the head 1 from collision with the medium during printing.

[0034] The joint between the cover member 103 and the base member 102 is bonded without any gaps, but in order to prevent damage to the flow path substrate 20 during bonding, a gap d is left between the bonding surface 103a of the cover member 103 and the bonding surface 20a of the flow path substrate 20.

[0035] At this time, gap d also varies due to variations in component dimensions, variations during head assembly, etc. Therefore, if a constant amount of adhesive 300 is applied, when gap d is high (wide), the adhesive 300 will not spill out as much, but it will be difficult to seal the space between bonding surfaces 103a and 20a. On the other hand, when gap d is low (narrow), it will be easier to seal the space between bonding surfaces 103a and 20a, but the adhesive 300 will be more likely to spill out.

[0036] Therefore, it is possible to control overflow and sealing by measuring the height of the base member 102 and the flow path substrate 20 each time and adjusting the amount of adhesive to be applied accordingly, but this requires a precision measuring device, measurement man-hours, and the adhesion of foreign matter during measurement, etc. Therefore, it is preferable to be able to control sealing and overflow when applying under constant adhesive application conditions, even if there is variation in the gap d.

[0037] Here, in order to completely fill the gap d, it is necessary to apply a larger amount of adhesive 300 to the joining surfaces 103a and 20a of the cover member 103 and the flow path substrate 20.

[0038] However, if the height of the bonding surface 20a of the flow path substrate 20 is close to the height of the bonding surface of the base member 102 with the cover member 103, the gap d becomes narrower and the adhesive 300 is more likely to overflow onto the surface (ejection surface 10a) of the nozzle plate 10.

[0039] Furthermore, the adhesive 300 that has spilled onto the ejection surface 10a of the nozzle plate 10 may be scraped off by the wiping member during wiping and become foreign matter, or the adhesive component may gradually dissolve as it is in contact with the liquid for a long time and adhere to the ejection surface 10a of the nozzle plate 10. As a result, a normal meniscus cannot be formed in the nozzle 11, which may lead to ejection defects.

[0040] On the other hand, if the height of the joining surface 20a of the flow path substrate 20 is far from the height of the joining surface of the base member 102 with the cover member 103, it is necessary to apply an amount of adhesive 300 that can fill the gap d.

[0041] In this case, in order to reduce residual stress, it is preferable to use a room temperature curing adhesive that cures at room temperature as the adhesive 300. However, if a room temperature curing adhesive 300 is used, it takes a long time to cure, and the adhesive may flow during curing, forming a leak path.

[0042] In particular, as shown in FIG. 4, when the cover member 103 is bonded to the flow path substrate 20 with the cover member 103 facing up and cured in this state, leak paths are likely to occur due to the flow during curing.

[0043] For this reason, even if the height of the gap d varies or even if a larger amount of adhesive 300 is applied, the adhesive 300 is less likely to spill out onto the ejection surface 10a of the nozzle plate 10, and if the amount of adhesive applied is the minimum required to fill as much of the gap d as possible, it is preferable to configure the adhesive 300 so that it remains at the applied position when the adhesive 300 hardens.

[0044] Therefore, in this embodiment, in order to prevent the adhesive 300 from spilling out onto the ejection surface 10a of the nozzle plate 10, the portion 103c of the cover member 103 that faces the nozzle plate 10 is formed in an eave shape.

[0045] As a result, even if the adhesive 300 overflows in a large amount, the adhesive 300 accumulates in the eaves-shaped portion 103c, and the adhesive 300 is less likely to overflow onto the ejection surface 10a of the nozzle plate 10.

[0046] Furthermore, the bonding surface 103a of the cover member 103 that bonds with the bonding surface 20a of the flow path substrate 20 is made liquid-philic, and the portion of the nozzle plate 10 that overlaps with the cover member 103 (ejection surface 10a) is made liquid-repellent.

[0047] This prevents the adhesive 300 that protrudes from between the nozzle plate 10 and the cover member 103 from spreading onto the ejection surface 10a of the nozzle plate 10.

[0048] Furthermore, the surface 103g of the cover member 103 (the surface opposite to the bonding surface 103a with the flow path substrate 20) is made liquid repellent.

[0049] As a result, even if a large amount of adhesive 300 protrudes from between the nozzle plate 10 and the cover member 103, it will be stopped by the edge 103h of the cover member 103.

[0050] In this embodiment, a part of the electrical member 92 including the wiring member 90 and the drive circuit 91 is disposed in the space 150 between the base member 102 and the side wall surface of the flow path substrate 20. A fluororesin 93 is applied to the surface of the electrical member 92 to make the surface of the electrical member 92 liquid repellent.

[0051] As a result, the adhesive 300 between the nozzle plate 10 and the cover member 103 adheres to the electrical component 92 This prevents the material from flowing to the side.

[0052] By providing such surface properties (liquid repellency and lyophilicity), even if the height of the gap d between the cover member 103 and the flow path substrate 20 varies due to variations in component dimensions, variations during assembly, etc., the range of application amount that can achieve both sealing and overflow can be widened, making manufacturing easier.

[0053] Even if the amount of adhesive 300 applied falls below the control range, the possibility of defects can be significantly reduced. By optimizing the adhesive application process, it is possible to suppress overflow of the adhesive and leaks caused by the adhesive flowing out, within the range that can be adjusted.

[0054] Next, a comparative example and an example will be described.

[0055] As Comparative Example 1, a head was produced in which the eaves-like portion 103c of the cover member 103 in the above embodiment was not present and the ejection surface 10a of the nozzle plate 10 was not formed with a liquid-repellent film.

[0056] As a comparative example 2, the cover member 103 in the above embodiment has a visor-like portion 103c, and the ejection surface 10a of the nozzle plate 10 is formed of a liquid-repellent film, but the ejection surface 10a is formed of a fluororesin. 93 A head with no coating was prepared.

[0057] Then, we carried out leak inspections, confirmed the state of overflow, and observed the cross-sectional shape. We confirmed that the amount of adhesive applied and the height of the gap d were the same through prior measurements.

[0058] In Comparative Example 1, there was no leakage, but the amount of overflow onto the nozzle plate 10 was large. In Comparative Example 2, there was no overflow or leakage. However, when looking at the cross-sectional shape, the electrical component was larger than that of the embodiment. 92 The adhesive 300 flows out to the side, the gap d is larger than in the embodiment, and if the amount of application is close to the lower limit, there is a risk of leakage.

[0059] In this embodiment, the ejection surface 10a of the nozzle plate 10 having liquid repellency is made of fluororesin. 93The contact angle of pure water on the surface 103g of the cover member 103 opposite to the bonding surface 103a that bonds with the flow path substrate 20 is set to 90° or more, and the contact angle of pure water on the bonding surface 20a of the flow path substrate 20, which has lyophilicity, and the bonding surface 103a of the cover member 103 is set to 40° or less. However, the effect of the present embodiment can be obtained if the pure contact angle of the liquid-repellent portion is set to 80° or more and the pure contact angle of the liquid-philic portion is set to 50° or less.

[0060] Next, a liquid ejection head according to a second embodiment of the present invention will be described with reference to Fig. 5. Fig. 5 is an explanatory side view of the liquid ejection head.

[0061] The liquid ejection head 101 has a cover member 103 joined to a flow path substrate 20 with an adhesive 300. The configuration of the cover member 103 and the joining to the flow path substrate 20 are the same as those in the first embodiment, and therefore a description thereof will be omitted.

[0062] The cover member 103 is joined to the frame member 70 together with the flow path substrate 20 .

[0063] Next, a different example of the third embodiment of the present invention will be described with reference to Fig. 6. Fig. 6 is an explanatory plan view of the ejection surface portion of one head according to the third embodiment.

[0064] In the first example shown in FIG. 6(a), a cover member 103 that covers the peripheral edge portions of the short sides 10b, 10b of the nozzle plate 10 is provided.

[0065] In the second example shown in FIG. 6(b), a cover member 103 is provided to cover the peripheral edge portions of the long sides 10c, 10c of the nozzle plate 10.

[0066] That is, in this embodiment, the cover member 103 is configured to cover the peripheral edge portions of a pair of opposing sides of the ejection surface 10 a of the nozzle plate 10 .

[0067] Next, an example of a liquid ejecting device according to the present invention will be described with reference to Figures 7 and 8. Figure 7 is a schematic explanatory diagram of the device, and Figure 8 is a plan explanatory diagram of an example of a head unit of the device.

[0068] The printing device 500, which is a device for ejecting this liquid, includes an input means 501 for feeding a continuous body 510, a guide and conveying means 503 for guiding and conveying the continuous body 510, such as continuous paper or continuous sheet, fed from the input means 501 to a printing means 505, the printing means 505 for ejecting liquid onto the continuous body 510 to print and form an image, a drying means 507 for drying the continuous body 510, and an ejection means 509 for ejecting the continuous body 510.

[0069] The continuous body 510 is fed from the original winding roller 511 of the carrying-in means 501 , guided and conveyed by the rollers of the carrying-in means 501 , the guide and conveying means 503 , the drying means 507 and the carrying-out means 509 , and wound up by the winding roller 591 of the carrying-out means 509 .

[0070] This continuum 510 is conveyed in the printing means 505 so as to face the head unit 550, and an image is printed by the liquid ejected from the head unit 550.

[0071] Here, as shown in FIG. 6, the head unit 550 includes three head modules 100A, 100B, and 100C according to the present invention on a common base member 552.

[0072] In the present application, when the head is a liquid ejection head, the ejected liquid may have a viscosity and surface tension that allow it to be ejected from the head, and is not particularly limited, but is preferably one whose viscosity becomes 30 mPa·s or less at room temperature and normal pressure, or upon heating or cooling. More specifically, the liquid may be a solution, suspension, emulsion, or the like containing a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a polymerizable compound, a resin, a surfactant, or the like, a biocompatible material such as DNA, amino acids, proteins, or calcium, or an edible material such as a natural colorant, and the like. These liquids can be used, for example, as inkjet inks, surface treatment liquids, liquids for forming components of electronic devices or light-emitting elements, or resist patterns for electronic circuits, and material liquids for 3D modeling.

[0073] Furthermore, liquid ejection devices include devices that are equipped with a head module, a head unit, etc., and eject liquid by driving a head. Liquid ejection devices include not only devices that can eject liquid onto objects to which the liquid can adhere, but also devices that eject liquid into air or liquid.

[0074] This "liquid ejecting device" can also include means for feeding, transporting, and discharging items onto which liquid can be attached, as well as pre-processing devices and post-processing devices.

[0075] For example, examples of "liquid ejecting devices" include image forming devices that eject ink to form images on paper, and three-dimensional modeling devices (three-dimensional modeling devices) that eject modeling liquid onto a powder layer formed from layers of powder in order to create a three-dimensional object (a three-dimensional model).

[0076] Furthermore, the term "liquid ejection device" is not limited to devices that use ejected liquid to visualize meaningful images such as letters and figures. For example, it also includes devices that form patterns that have no meaning in themselves, and devices that create three-dimensional images.

[0077] The above-mentioned "object onto which a liquid can adhere" means an object onto which a liquid can adhere at least temporarily, an object onto which the liquid can adhere and stick, an object onto which the liquid can penetrate, etc. Specific examples include media such as paper, recording paper, film, and cloth, electronic circuit boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, includes all objects onto which a liquid can adhere.

[0078] The material of the "substance to which a liquid can adhere" may be any material to which a liquid can adhere, even temporarily, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, or ceramics.

[0079] Furthermore, the "liquid ejection device" may be a device in which a liquid ejection head and an object onto which liquid can be attached move relatively, but is not limited to this. Specific examples include a serial type device in which a liquid ejection head moves, and a line type device in which a liquid ejection head does not move.

[0080] Other examples of "liquid ejecting devices" include a treatment liquid application device that ejects a treatment liquid onto paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and an injection granulation device that ejects a composition liquid in which raw materials are dispersed through a nozzle to granulate fine particles of the raw materials.

[0081] In the present application, the terms image formation, recording, printing, copying, printing, modeling, etc. are all synonymous. [Explanation of symbols]

[0082] 1 head 10 Nozzle plate 11 nozzles 20 Flow path substrate 30 diaphragm 70 Common flow path member (frame member) 100 Head Module 101 Liquid ejection head 102 Base member 103 Cover member 300 Adhesive 500 Printing device (liquid ejecting device) 501 Means of transport 505 Printing means 510 Continuum 507 Drying means 509 Export means 550 head unit

Claims

1. a nozzle plate in which nozzles for ejecting liquid are formed; a head including a flow path substrate that forms individual flow paths that communicate with the nozzles; a cover member that covers at least one side of the ejection surface of the nozzle plate of the head, the nozzle plate has an outer shape smaller than the outer shape of the flow path substrate; At least the cover member is bonded to an outer region of the nozzle plate on a surface of the flow path substrate facing the nozzle plate with an adhesive; the ejection surface of the nozzle plate is liquid-repellent; each of the surfaces of the flow path substrate and the cover member joined by the adhesive has lyophilicity; the cover member is also joined to a member disposed with a space between it and a side wall surface of the flow path substrate, an electric member connected to a driving means for pressurizing the liquid in the individual flow path; the electrical member includes a portion disposed in the space, A fluororesin is applied to a surface of the electrical component that faces the cover component and is disposed in the space. A head module characterized by:

2. The thickness of the cover member at a portion facing the nozzle plate is thinner than the thickness of a portion joined to the flow path substrate. The head module according to claim 1 .

3. The cover member has a surface facing the nozzle plate that is lyophilic.

3. The head module according to claim 1 or 2.

4. The cover member has a surface opposite to the surface bonded to the flow path substrate that is liquid repellent.

4. The head module according to claim 1, wherein the first and second electrodes are electrically connected to the first and second electrodes.

5. The adhesive is a room temperature curing adhesive.

5. The head module according to claim 1.

6. A plurality of the heads; and one of the cover members.

6. The head module according to claim 1, wherein the first and second electrodes are electrically connected to the first and second electrodes.

7. a nozzle plate in which nozzles for ejecting liquid are formed; a flow path substrate forming individual flow paths communicating with the nozzles; a cover member that covers at least one side of the ejection surface of the nozzle plate, the nozzle plate has an outer shape smaller than the outer shape of the flow path substrate; At least the cover member is bonded to an outer region of the nozzle plate on a surface of the flow path substrate facing the nozzle plate with an adhesive; the ejection surface of the nozzle plate is liquid-repellent; each of the surfaces of the flow path substrate and the cover member joined by the adhesive has lyophilicity; the cover member is also joined to a member disposed with a space between it and a side wall surface of the flow path substrate, an electric member connected to a driving means for pressurizing the liquid in the individual flow path; the electrical member includes a portion disposed in the space, A fluororesin is applied to a surface of the electrical component that faces the cover component and is disposed in the space. A liquid ejection head characterized by:

8. The thickness of the cover member at a portion facing the nozzle plate is thinner than the thickness of a portion joined to the flow path substrate.

8. The liquid ejection head according to claim 7.

9. The cover member has a surface facing the nozzle plate that is lyophilic.

9. A liquid ejection head according to claim 7 or 8.

10. The cover member has a surface opposite to the surface bonded to the flow path substrate that is liquid repellent.

10. A liquid ejection head according to claim 7, wherein the liquid ejection head is a liquid ejection head.

11. A head module according to any one of claims 1 to 6 or a liquid ejection head according to any one of claims 7 to 10. A liquid ejection device comprising:

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