Liquid spray head

Abstract

To provide a liquid spray head that can suppress the overflow of adhesive. [Solution] The liquid spray head 10 comprises a fixed plate 15, a holder 13 stacked on the fixed plate 15 in the Z1 direction and having a first surface 13f, and an adhesive 19 that adheres the fixed plate 15 and the first surface 13f. The first surface 13f has an adhesive region Ra that is in contact with the adhesive 19, and a first line segment passing through a first point in the adhesive region Ra is longer than a second line segment passing through a second point. The region R1 of the first surface 13f that overlaps with the first line segment in the Z1 direction has a first adhesive region R1a and a first recess 13c_1. The second adhesive region R2a of the adhesive region Ra that overlaps with the second line segment in the Z1 direction does not have a recess whose distance in the Z-axis direction from the fixed plate 15 is greater than the distance Lr1 between the fixed plate 15 and the first adhesive region R1a in the Z-axis direction, and whose length in the direction along the second line segment is greater than or equal to the length Lc1 in the T-axis direction of the first recess 13c_1.

Description

Technical Field

[0001] The present invention relates to a liquid injection head that injects liquid from a nozzle.

Background Art

[0002] Patent Document 1 discloses a liquid injection head including a head chip that injects liquid, a holder unit that houses and supports a plurality of head chips, and a fixing plate for fixing the plurality of head chips to the holder unit, in which the holder unit and the fixing plate are fixed by an adhesive.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the liquid injection head as described above, it is desirable to suppress the excess adhesive from protruding outside the adhesion area between the holder and the fixing plate. Therefore, by providing a recess in the holder unit or the fixing plate, the excess adhesive can be made to flow into the recess, thereby suppressing the protrusion. However, a part of the holder unit or the fixing plate may have a narrow adhesion area width and no recess for allowing the excess adhesive to flow in. In such a case, instead of providing a recess, the protrusion can also be suppressed by increasing the distance between the fixing plate and the holder unit. However, since the thickness of the adhesive increases, there is a risk that the adhesive strength may decrease. Therefore, when a part of the adhesion area includes a narrow portion, it is desirable to suppress the protrusion of the adhesive while suppressing the decrease in strength. These problems occur not only in the adhesion between the fixing plate and the holder unit but also in the adhesion between other members. [Means for solving the problem]

[0005] The liquid spray head comprises a first member, a second member stacked in a first direction on the first member and having a first surface, and an adhesive for bonding the first member and the first surface, wherein the first surface has an adhesive region in contact with the adhesive, and when viewed in the first direction, a first line segment that passes through a first point in the adhesive region and connects the ends of the adhesive region in the shortest distance is longer than a second line segment that passes through a second point different from the first point in the adhesive region and connects the ends of the adhesive region in the shortest distance, and the region of the first surface that overlaps the first line segment in the first direction has a first adhesive region which is part of the adhesive region and a first recess which is recessed in the first direction more than the first adhesive region, and the second adhesive region of the adhesive region that overlaps the second line segment in the first direction does not have a recess in which the distance from the first member in the first direction is greater than the distance from the first member to the first adhesive region in the first direction and the length in the direction along the second line segment is greater than or equal to the length of the first recess in the direction along the first line segment. [Brief explanation of the drawing]

[0006] [Figure 1] This is a schematic diagram showing an example of the configuration of a liquid injection device according to the first embodiment. [Figure 2] This is a perspective view of a liquid injection module having a liquid injection head according to the first embodiment. [Figure 3] Figure 2 shows an exploded perspective view of the liquid injection head. [Figure 4] This is a disassembled perspective view of the head tip of a liquid spray head. [Figure 5] This is a cross-sectional view taken along line VI-VI in Figure 4. [Figure 6] Figure 2 is a plan view of the liquid spray head holder. [Figure 7] This is an enlarged view of the area within frame A in Figure 6. [Figure 8] This is an enlarged view of the area within frame B in Figure 7. [Figure 9] This is an enlarged view of the area within frame C in Figure 7. [Figure 10] It is a cross-sectional view passing through the first line segment L1 in FIG. 7. [Figure 11] It is a cross-sectional view passing through the second line segment L2 in FIG. 7. [Figure 12] It is a cross-sectional view passing through the third line segment L3 in FIG. 7. [Figure 13] It is a cross-sectional view taken along the line E-E in FIG. 7. [Figure 14] It is a schematic plan view of the holder of the liquid ejection head according to the first modification. [Figure 15] It is a cross-sectional view passing through the first line segment L1 in FIG. 14. [Figure 16] It is a schematic plan view of the holder of the liquid ejection head according to the second modification. [Figure 17] It is a cross-sectional view passing through the first line segment L1 in FIG. 16. [Figure 18] It is a schematic plan view of the holder of the liquid ejection head according to the third modification. [Figure 19] It is a cross-sectional view passing through the first line segment L1 in FIG. 18. [Figure 20] It is a cross-sectional view of the holder and the fixing plate of the liquid ejection head according to the fourth modification. [Figure 21] It is a cross-sectional view of the holder and the fixing plate of the liquid ejection head according to the fifth modification. [Figure 22] It is a plan view of the second flow path member of the liquid ejection head according to the second embodiment. [Figure 23] It is a cross-sectional view taken along the line F-F in FIG. 22.

MODE FOR CARRYING OUT THE INVENTION

[0007] Hereinafter, preferred embodiments according to the present disclosure will be described while referring to the accompanying drawings. In the drawings, the dimensions and scales of each part are appropriately different from the actual ones, and there are also parts schematically shown for easy understanding. Further, the scope of the present disclosure is not limited to these embodiments unless there is a description to specifically limit the present disclosure in the following description.

[0008] Hereinafter, for convenience of explanation, X-axis, Y-axis, and Z-axis that intersect each other are appropriately used. One direction along the X-axis is referred to as the X1 direction, and the direction opposite to the X1 direction is referred to as the X2 direction. Similarly, the directions opposite to each other along the Y-axis are referred to as the Y1 direction and the Y2 direction. Also, the directions opposite to each other along the Z-axis are referred to as the Z1 direction and the Z2 direction. Further, when the X1 direction and the X2 direction are not limited, the direction along the X-axis is referred to as the X-axis direction. Similarly, when the Y1 direction and the Y2 direction are not limited, the direction along the Y-axis is referred to as the Y-axis direction, and when the Z1 direction and the Z2 direction are not limited, the direction along the Z-axis is referred to as the Z-axis direction.

[0009] Here, typically, the Z-axis is a vertical axis, and the Z2 direction corresponds to the downward direction in the vertical direction. However, the Z-axis may not be a vertical axis and may be inclined with respect to the vertical axis. Also, the X-axis, Y-axis, and Z-axis typically intersect each other at right angles, but are not limited thereto, and for example, they may intersect at an angle within the range of 80° or more and 100° or less.

[0010] 1. First Embodiment 1-1. Liquid Injection Device FIG. 1 is a schematic diagram showing a configuration example of a liquid injection device 100 according to an embodiment. The liquid injection device 100 is an inkjet printing device that injects ink as droplets onto a medium M. Ink is an example of a "liquid". The liquid injection device 100 of the present embodiment is a so-called line-type printing device in which a plurality of nozzles N (see FIG. 4) for injecting ink are distributed over the entire range in the width direction of the medium M. The medium M is typically printing paper. Note that the medium M is not limited to printing paper, and may be a printing object of any material such as a resin film or a fabric.

[0011] As shown in FIG. 1, the liquid injection device 100 includes a liquid storage unit 60, a control unit 20, a transport mechanism 30, a liquid injection module 40, and a circulation mechanism 50.

[0012] The liquid storage section 60 is a container for storing ink. Specific embodiments of the liquid storage section 60 include, for example, a cartridge detachable from the liquid injection device 100, a bag-shaped ink pack made of a flexible film, and an ink tank from which ink can be refilled. The type of ink stored in the liquid storage section 60 is arbitrary.

[0013] Although not shown in the figures, the liquid storage section 60 of this embodiment includes a first liquid container and a second liquid container. The first liquid container stores a first ink. The second liquid container stores a second ink of a different type from the first ink. The first ink and the second ink are, for example, inks of different colors. However, the first ink and the second ink may be the same type of ink.

[0014] The control unit 20 controls the operation of each element of the liquid injection device 100. Here, the control unit 20 outputs a control signal SI for controlling the ink ejection operation in the liquid injection module 40, and a drive signal Com for driving the liquid injection module 40. The control unit 20 includes, for example, a processing circuit such as a CPU (Central Processing Unit) or FPGA (Field Programmable Gate Array), and a storage circuit such as a semiconductor memory. Various programs and various data are stored in the storage circuit. The processing circuit realizes various controls by executing the programs and using the data as appropriate.

[0015] The conveying mechanism 30 conveys the medium M in direction DM under the control of the control unit 20. In this embodiment, direction DM is the Y2 direction. In the example shown in Figure 1, the conveying mechanism 30 includes a long conveying roller along the X axis and a motor that rotates the conveying roller. The conveying mechanism 30 is not limited to a configuration using a conveying roller; for example, it may also use a drum or an endless belt that conveys the medium M while it is attracted to the outer surface by electrostatic force or the like.

[0016] The liquid injection module 40, under the control of the control unit 20, injects ink supplied from the liquid reservoir 60 via the circulation mechanism 50 onto the medium M in the Z2 direction from each of the multiple nozzles N. The liquid injection module 40 has multiple liquid injection heads 10 arranged so that the multiple nozzles N are distributed over the entire area of ​​the medium M in the X-axis direction, and is a long line head extending in the X-axis direction. The injection of ink from the multiple liquid injection heads 10 is performed in parallel with the transport of the medium M by the transport mechanism 30, thereby forming an image of ink on the surface of the medium M. The liquid injection module 40 may also be a long line head extending in the X-axis direction, consisting only of a single liquid injection head 10 arranged so that the multiple nozzles N are distributed over the entire area of ​​the medium M in the X-axis direction.

[0017] In the example shown in Figure 1, the liquid storage unit 60 is connected to the liquid injection module 40 via a circulation mechanism 50. The circulation mechanism 50 supplies ink to the liquid injection module 40 and recovers the ink discharged from the liquid injection module 40 for resupply to the liquid injection module 40. The circulation mechanism 50 includes, for example, a sub-tank for storing ink, a supply channel for supplying ink from the sub-tank to the liquid injection module 40, a recovery channel for recovering ink from the liquid injection module to the sub-tank, and a pump for transferring the ink. These are provided for each of the first and second inks described above. The operation of the circulation mechanism 50 as described above can suppress the increase in ink viscosity and reduce the accumulation of air bubbles in the ink.

[0018] 1-2. Liquid injection module Figure 2 is a perspective view of a liquid injection module 40 having a liquid injection head 10 according to an embodiment. As shown in Figure 2, the liquid injection module 40 has a support 41 and a plurality of liquid injection heads 10.

[0019] The support 41 is a member that supports multiple liquid injection heads 10. In the example shown in Figure 2, the support 41 is a plate-shaped member made of metal or the like, and is provided with mounting holes 41a for attaching multiple liquid injection heads 10. Multiple liquid injection heads 10 are inserted into the mounting holes 41a in an orderly fashion along the X-axis, and each liquid injection head 10 is fixed to the support 41 by screws or the like. In Figure 2, two liquid injection heads 10 are typically shown. The number of liquid injection heads 10 in the liquid injection module 40 is arbitrary. Also, the shape of the support 41 is not limited to the example shown in Figure 2 and is arbitrary.

[0020] 1-3. Liquid spray head Figure 3 is an exploded perspective view of the liquid injection head 10 shown in Figure 2. As shown in Figure 3, the liquid injection head 10 includes a flow path member 11, a circuit board 12, a holder 13, head tips 14-1 to 14-6, a fixing plate 15, wiring boards 16-1 to 16-6, drive circuits 17-1 to 17-6, and separation members 18-1 to 18-3.

[0021] In the following, head chips 14-1 to 14-6 may be referred to simply as head chip 14 without distinction, wiring boards 16-1 to 16-6 may be referred to simply as wiring board 16 without distinction, drive circuits 17-1 to 17-6 may be referred to simply as drive circuit 17 without distinction, and separating members 18-1 to 18-3 may be referred to simply as separating member 18 without distinction.

[0022] The circuit board 12, flow path member 11, holder 13, multiple head chips 14-1 to 14-6, and fixing plate 15 are stacked in the Z2 direction and joined to each other by adhesive or screws. A wiring board 16 is drawn out from each head chip 14, and the wiring board 16 is connected to the circuit board 12 through the wiring hole 13a of the holder 13 (described later) and the wiring hole 11a of the flow path member 11 (described later). A drive circuit 17 is provided on each wiring board 16. A separation member 18 is inserted from between the flow path member 11 and the circuit board 12 into the wiring hole 13a of the holder 13 (described later) and the wiring hole 11a of the flow path member 11 (described later), preventing electrical contact between the drive circuit 17 and the holder 13. The parts of the liquid injection head 10 will now be briefly described in order based on Figure 3.

[0023] The flow channel member 11 is a structure in which a flow channel for flowing ink between the circulation mechanism 50 and the multiple head chips 14 is provided inside. As shown in Figure 3, the flow channel member 11 is provided with multiple wiring holes 11a and connecting pipes 11b-1 to 11b-4. In addition, although not shown in Figure 3, the flow channel member 11 is provided with a supply channel for supplying first ink to the multiple head chips 14, a supply channel for supplying second ink to the multiple head chips 14, a discharge channel for discharging first ink from the multiple head chips 14, and a discharge channel for discharging second ink from the multiple head chips 14. In the following, the connecting pipes 11b-1 to 11b-4 may be referred to simply as connecting pipe 11b without distinction.

[0024] The flow channel member 11 has layers 11c1 and 11c2, which are stacked in this order in the Z2 direction. By appropriately providing grooves or holes in these layers, the aforementioned flow channels, such as the supply channel and discharge channel, are formed. Layers 11c1 and 11c2 are made of, for example, a resin material and are formed by injection molding. Layers 11c1 and 11c2 are joined to each other, for example, by adhesive. Note that the thickness and number of layers constituting the flow channel member 11 are not limited to the example shown in Figure 3 and are arbitrary.

[0025] Each of the multiple wiring holes 11a is a hole for passing through the wiring board 16 and penetrates the flow path member 11 in the Z-axis direction. In the example shown in Figure 3, a wiring hole 11a is provided for each head chip 14, and each wiring hole 11a is used not only for passing through the wiring board 16 but also for passing through the separation member 18. Each of the connecting tubes 11b-1 to 11b-4 protrudes from the layer 11c1 in the Z1 direction. Connecting tube 11b-1 is a tube that constitutes a flow path for introducing the first ink into the flow path member 11. Connecting tube 11b-2 is a tube that constitutes a flow path for introducing the second ink into the flow path member 11. On the other hand, connecting tube 11b-3 is a tube that constitutes a flow path for discharging the first ink from the flow path member 11. Connecting tube 11b-4 is a tube that constitutes a flow path for discharging the second ink from the flow path member 11.

[0026] The circuit board 12 is a mounting component for electrically connecting the control unit 20 and the wiring board 16. The circuit board 12 is, for example, a rigid wiring board. A connector 12c is installed on the side of the circuit board 12 facing the Z1 direction. The connector 12c is a connecting component for electrically connecting to the control unit 20. The circuit board 12 is also provided with a plurality of wiring holes 12a and a plurality of holes 12b. Each wiring hole 12a is a hole for passing the wiring board 16 through. Terminals (not shown) that connect to the wiring board 16 through the wiring holes 12a are provided on the side of the circuit board 12 facing the Z1 direction. In the example shown in Figure 3, a wiring hole 12a is provided for each head chip 14. Each hole 12b is a hole for passing the aforementioned connecting tube 11b through. The connecting tube 11b through the hole 12b protrudes from the circuit board 12 in the Z1 direction.

[0027] The holder 13 is a structure that houses and supports multiple head chips 14. The holder 13 is made of, for example, a resin material or a metal material. The holder 13 is plate-shaped and extends in a direction perpendicular to the Z axis. The holder 13 is provided with multiple wiring holes 13a, a housing section 13b, an outer peripheral wall 13w, and a bottom section 13e. The outer peripheral wall 13w is a wall that surrounds the multiple housing sections 13b when viewed along the Z axis. Each wiring hole 13a is a hole for passing a wiring board 16 and has a side surface Sa (see Figure 11). In the example shown in Figure 3, a wiring hole 13a is provided for each head chip 14, and each wiring hole 13a is used not only for passing the wiring board 16 but also for passing a separation member 18, and allows connection between the flow path member 11 and each head chip 14. The housing section 13b is a portion recessed in the Z1 direction, provided on the Z2 direction surface of the holder 13, and houses multiple head chips 14. The housing section 13b has a side surface Sb (see Figure 10). In this way, the holder 13 holds the head tips 14-1 to 14-6 between itself and the fixing plate 15. That is, the outer peripheral wall 13w surrounds the head tip 14 when viewed along the Z axis. The outer peripheral wall 13w also has flange portions 13d that protrude in the Y1 and Y2 directions, which are provided to fix the liquid injection head 10 to the support 41. The bottom portion 13e defines the bottom surface of the housing section 13b. The bottom portion 13e surrounds a plurality of wiring holes 13a when viewed along the Z axis.

[0028] In this embodiment, the holder 13 holds six head tips 14-1 to 14-6. These head tips 14 are arranged in the X2 direction in the order of head tips 14-1, 14-2, 14-3, 14-4, 14-5, and 14-6. Here, head tips 14-1, 14-3, and 14-5 are positioned offset in the Y1 direction relative to head tips 14-2, 14-4, and 14-6. However, head tips 14-1 to 14-6 have overlapping portions when viewed in the X1 or X2 direction. Also, the arrangement direction DN (see Figure 4) of the multiple nozzles N of head tips 14-1 to 14-6, which will be described later, are parallel to each other. Furthermore, each of the head tips 14-1 to 14-6 is arranged such that its arrangement direction DN is inclined with respect to the direction DM, which is the transport direction of the medium M.

[0029] Each head tip 14 ejects ink. Specifically, although not shown in Figure 3, each head tip 14 has a plurality of nozzles N for ejecting first ink and a plurality of nozzles N for ejecting second ink. These nozzles N are provided on the nozzle surface FN, which is the surface of each head tip 14 facing the Z2 direction. The configuration of the head tip 14 will be described later. Note that a plan view taken in a direction perpendicular to the nozzle surface FN is also simply called a "plan view".

[0030] The fixing plate 15 is a plate member for fixing multiple head chips 14 to the holder 13. Specifically, the fixing plate 15 is positioned between the holder 13 and the multiple head chips 14, and is fixed to the holder 13 with adhesive. The fixing plate 15 is made of, for example, a metal material. However, the material constituting the fixing plate 15 is not limited to metal, and may be, for example, resin.

[0031] The fixing plate 15 is provided with exposure openings 15a-1 to 15a-6 for exposing the multiple nozzles N described later on the head tips 14-1 to 14-6. The exposure openings 15a-1 to 15a-6 correspond one-to-one with the head tips 14-1 to 14-6. Thus, the fixing plate 15 has exposure openings 15a-1 to 15a-6 for exposing the multiple nozzles N described later on the head tips 14-1 to 14-6, and the head tips 14-1 to 14-6 are fixed to the fixing plate 15. Hereafter, the exposure openings 15a-1 to 15a-6 may be referred to simply as the exposure opening 15a without distinction.

[0032] The wiring board 16 is a flexible substrate containing wiring that is electrically connected to the piezoelectric element 14f, which will be described later. For example, it may be an FPC (Flexible Printed Circuits) or a COF (Chip On Film). A drive circuit 17 is provided on one side of the wiring board 16. Thus, the wiring board 16 has the drive circuit 17 and is electrically connected to the head chip 14. That is, the wiring board 16-1 has the drive circuit 17-1 and is electrically connected to the head chip 14-1. The wiring board 16-2 has the drive circuit 17-2 and is electrically connected to the head chip 14-2. Similarly, the wiring boards 16-3 to 16-6 have the drive circuits 17-3 to 17-6 and are electrically connected to the head chips 14-3 to 14-6.

[0033] The drive circuit 17 includes multiple switching elements corresponding to each of the multiple piezoelectric elements 14f corresponding to the multiple nozzles N described later, and is a circuit that selects whether or not to supply a drive signal Com to each piezoelectric element 14f.

[0034] The separating member 18 is positioned between the drive circuit 17 and the holder 13 to prevent electrical contact between the drive circuit 17 and the holder 13. In the example shown in Figure 3, the separating member 18 is a structure made by folding a sheet-like or film-like material.

[0035] 1-4. Head Tip Figure 4 is an exploded perspective view of the head tip 14 of the liquid injection head 10. Figure 5 is a cross-sectional view taken along the line VI-VI in Figure 4. For convenience of explanation, the V-axis and W-axis, which intersect the Z-axis and intersect each other, will be used as appropriate below. One direction along the V-axis will be referred to as the V1 direction, and the direction opposite to the V1 direction will be referred to as the V2 direction. Similarly, the opposite directions along the W-axis will be referred to as the W1 direction and the W2 direction. If the V1 and V2 directions are not limited, the direction along the V-axis will be referred to as the V-axis direction. Similarly, if the W1 and W2 directions are not limited, the direction along the W-axis will be referred to as the W-axis direction. Here, the V-axis is an axis parallel to the array direction DN in which the nozzle rows Ln1 and Ln2 described later extend, and extends in a direction inclined with respect to the Y-axis. The W-axis extends in a direction inclined with respect to the X-axis. While the V-axis and W-axis are typically orthogonal to each other, they are not limited to this; for example, they can intersect at an angle within the range of 80° to 100°.

[0036] As shown in Figures 4 and 5, the head tip 14 has a plurality of nozzles N arranged in the V-axis direction.

[0037] The multiple nozzles N of the head tip 14 are divided into nozzle rows Ln1 and nozzle row Ln2, which are spaced apart from each other in the W-axis direction. Each of nozzle row Ln1 and nozzle row Ln2 is a collection of multiple nozzles N arranged linearly in the V-axis direction.

[0038] The head tip 14 has a configuration that is approximately symmetrical with respect to each other in the W-axis direction. However, the positions of the multiple nozzles N of nozzle row Ln1 and the multiple nozzles N of nozzle row Ln2 in the V-axis direction may coincide or differ from each other. Figures 4 and 5 illustrate a configuration in which the positions of the multiple nozzles N of nozzle row Ln1 and the multiple nozzles N of nozzle row Ln2 coincide with each other in the V-axis direction.

[0039] As shown in Figures 4 and 5, the head chip 14 includes a flow channel substrate 14a, a pressure chamber substrate 14b, a nozzle plate 14c, a vibration absorber 14d, a diaphragm 14e, a plurality of piezoelectric elements 14f, a cover 14g, and a case 14h.

[0040] The flow channel substrate 14a and the pressure chamber substrate 14b are stacked in this order in the Z1 direction, forming a flow channel for supplying ink to multiple nozzles N. A diaphragm 14e, multiple piezoelectric elements 14f, a cover 14g, and a case 14h are installed in the region located in the Z1 direction from the stack consisting of the flow channel substrate 14a and the pressure chamber substrate 14b. On the other hand, a nozzle plate 14c and a vibration absorber 14d are installed in the region located in the Z2 direction from the stack. Each element of the head chip 14 is generally a long plate-like member in the V-axis direction, and is joined to each other, for example, by adhesive. The elements of the head chip 14 will be described in order below.

[0041] The nozzle plate 14c is a plate-shaped member provided with multiple nozzles N in nozzle rows Ln1 and Ln2, respectively. Each of the multiple nozzles N is a through-hole through which ink passes. Here, the surface of the nozzle plate 14c facing the Z2 direction is the nozzle surface FN. The nozzle plate 14c is manufactured by processing a silicon single crystal substrate using semiconductor manufacturing technology, such as dry etching or wet etching. However, other known methods and materials may be used in the manufacture of the nozzle plate 14c as appropriate. Furthermore, the shape of the nozzles N is not limited to the illustrated example and is arbitrary.

[0042] The flow channel substrate 14a is provided with a first flow channel P1, a plurality of supply flow channels Pa, and a plurality of communication flow channels Na for each of the nozzle rows Ln1 and Ln2. The first flow channel P1 communicates with the nozzle N and is a flow channel upstream of the nozzle N, and is composed of an elongated hole extending in the V-axis direction in a plan view in the Z-axis direction. Each of the supply flow channels Pa and communication flow channels Na is a through-hole formed for each nozzle N. Each supply flow channel Pa communicates with the first flow channel P1.

[0043] The pressure chamber substrate 14b is a plate-shaped member provided with a plurality of pressure chambers C for each of the nozzle rows Ln1 and Ln2. The plurality of pressure chambers C are arranged in the V-axis direction. Each pressure chamber C is formed for each nozzle N and is a long, elongated space extending in the W-axis direction in a plan view.

[0044] The channel substrate 14a and the pressure chamber substrate 14b are manufactured, for example, by processing a silicon single crystal substrate using semiconductor manufacturing technology, similar to the nozzle plate 14c described above. However, other known methods and materials may be used as appropriate for the manufacture of the channel substrate 14a and the pressure chamber substrate 14b.

[0045] The pressure chamber C is located between the flow channel substrate 14a and the diaphragm 14e. Multiple pressure chambers C are arranged in the V-axis direction for each of the nozzle rows Ln1 and Ln2. The pressure chamber C also communicates with the communication channel Na and the supply channel Pa, respectively. Therefore, the pressure chamber C communicates with the nozzle N via the communication channel Na and with the first channel P1 via the supply channel Pa.

[0046] A diaphragm 14e is positioned on the surface of the pressure chamber substrate 14b facing the Z1 direction. The diaphragm 14e is an elastically vibrating plate-shaped member. Although not shown, the diaphragm 14e has, for example, an elastic film and an insulating film, which are stacked in this order in the Z1 direction. The elastic film is composed of, for example, silicon oxide (SiO2) and is formed by thermal oxidation of one surface of a silicon single crystal substrate. The insulating film is composed of, for example, zirconium oxide (ZrO2) and is formed by forming a zirconium layer by sputtering and then thermally oxidizing the layer.

[0047] Furthermore, the diaphragm 14e is not limited to the lamination of the elastic film and insulating film described above, but may be composed of a single layer or three or more layers. Also, the material of each layer constituting the diaphragm 14e is not limited to the materials described above, but may be silicon or silicon nitride, for example.

[0048] On the surface of the diaphragm 14e facing the Z1 direction, multiple piezoelectric elements 14f, each corresponding to a nozzle N, are arranged as driving elements for each of the nozzle rows Ln1 and Ln2, and one end of the wiring board 16 is connected to them. Each piezoelectric element 14f is a passive element that deforms when a potential corresponding to a driving signal Com is supplied through the wiring board 16, causing pressure fluctuations in the ink in the pressure chamber C. Each piezoelectric element 14f is elongated in the W-axis direction when viewed from above. Multiple piezoelectric elements 14f are arranged in the V-axis direction to correspond to multiple pressure chambers C. The piezoelectric elements 14f overlap the pressure chamber C when viewed from above.

[0049] Although not shown in the diagram, each piezoelectric element 14f has a first electrode, a piezoelectric body, and a second electrode, and these are stacked in this order in the Z1 direction. The first electrode is an individual electrode that is spaced apart from each other for each piezoelectric element 14f. A potential corresponding to the drive signal Com is supplied to the first electrode. The second electrode is a strip-shaped common electrode that extends in the V-axis direction so as to be continuous across the plurality of piezoelectric elements 14f. A constant potential is supplied to the second electrode, for example. Examples of metallic materials for these electrodes include platinum (Pt), aluminum (Al), nickel (Ni), gold (Au), and copper (Cu), and one of these can be used alone or two or more can be used in combination in the form of an alloy or stacking. The piezoelectric body is made of a piezoelectric material such as lead zirconate titanate (Pb(Zr,Ti)O3). In the piezoelectric element 14f described above, when a voltage is applied between the first electrode and the second electrode, the piezoelectric body deforms due to the inverse piezoelectric effect. When the diaphragm 14e vibrates in conjunction with this deformation, the pressure in the pressure chamber C fluctuates, causing ink to be ejected from the nozzle N. Alternatively, instead of the piezoelectric element 14f, a heating element that generates bubbles by heating the ink in the pressure chamber C to eject ink from the nozzle N may be used as the driving element.

[0050] The cover 14g is a plate-shaped member installed on the surface of the diaphragm 14e facing the Z1 direction, protecting the multiple piezoelectric elements 14f and reinforcing the mechanical strength of the diaphragm 14e. Here, the multiple piezoelectric elements 14f are housed in the space S between the cover 14g and the diaphragm 14e. The cover 14g is made of, for example, a resin material.

[0051] Case 14h is a case for storing ink supplied to multiple pressure chambers C. Case 14h is made of, for example, a resin material. Case 14h is provided with a second flow path P2 for each of the nozzle rows Ln1 and Ln2. The second flow path P2 is a space connected to the aforementioned first flow path P1 and is composed of an elongated hole extending in the V-axis direction in a plan view in the Z-axis direction. The second flow path P2 is in communication with the nozzle N and, together with the first flow path P1, functions as a reservoir R for storing ink supplied to multiple pressure chambers C. Case 14h is provided with two openings HL for each reservoir R. Of the two openings HL, one opening HL is an inlet for supplying ink to the reservoir R, and the other opening HL is an outlet for discharging ink from the reservoir R. The ink in each reservoir R is supplied to the pressure chamber C via each supply flow path Pa. Furthermore, the position and number of openings HL for each reservoir R are not limited to the examples in Figures 4 and 5, but are arbitrary.

[0052] The vibration absorber 14d, also called the compliance substrate, is a flexible resin film that forms the wall surface of the reservoir R and absorbs pressure fluctuations of the ink in the reservoir R. The vibration absorber 14d may also be a flexible thin plate made of metal. The surface of the vibration absorber 14d facing the Z1 direction is joined to the flow channel substrate 14a by adhesive or the like.

[0053] 1-5. Regarding the adhesive joint between the holder and the fixing plate Figure 6 is a plan view of only the holder 13 of the two liquid spray heads 10 shown in Figure 2, viewed in the Z1 direction. Figure 7 is an enlarged view of the area within frame A in Figure 6. Figures 8 and 9 are enlarged views of the areas within frame B and frame C in Figure 7, respectively.

[0054] As shown in Figure 6, the outer peripheral walls 13w of the holders 13 of adjacent liquid injection heads 10 in the X-axis direction have overlapping portions in the Y-axis direction. The outer peripheral wall 13w has an end in the X-axis direction and an end in the Y-axis direction. The end in the X-axis direction has a portion that is aligned with the Y-axis direction and a portion that is aligned with the V-axis direction. Furthermore, the end in the X-axis direction faces the end in the X-axis direction of the outer peripheral wall 13w of the holder 13 of the liquid injection head 10 adjacent to it in the X-axis direction. In this embodiment, the end in the X-axis direction has a portion that is aligned with the Y-axis direction and a portion that is aligned with the V-axis direction, but the end in the X-axis direction may have a portion that is aligned with the Y-axis direction and a portion that is aligned with the X-axis direction. The end of the Y-axis aligns with the X-axis direction.

[0055] As shown in Figure 7, the outer peripheral wall 13w of the holder 13 has a first surface 13f which faces in the Z2 direction. As shown in Figure 10, the fixing plate 15 has a second surface 15f which faces the holder 13, i.e., in the Z1 direction. The holder 13 and the fixing plate 15 are bonded together by adhesive 19, which bonds the first surface 13f and the second surface 15f. It is desirable that there be only one type of adhesive 19. Furthermore, it is desirable that the adhesive 19 used to bond the holder 13 and the fixing plate 15 not be applied at different times. That is, it is desirable that the remaining adhesive 19 be applied before some of the adhesive 19 has been applied and cured.

[0056] The first surface 13f includes irregularities and non-planar areas. The areas represented by the dot patterns in Figures 6, 7, 8, and 9 are the adhesive areas Ra on the first surface 13f to which the adhesive 19 is applied. In other words, the first surface 13f has an adhesive area Ra which is the area in contact with the adhesive 19. The adhesive area Ra is the area to which the adhesive 19 is applied and may include areas that are not bonded to the fixing plate 15. In other words, a portion of the adhesive 19 in contact with the adhesive area Ra may not be in contact with the fixing plate 15.

[0057] As shown in Figure 7, the first line segment L1 is defined as the line segment that passes through an arbitrary first point D1 within the adhesive region Ra when viewed in the Z1 direction and connects the ends of the adhesive region Ra in the shortest possible path. Similarly, as shown in Figures 7 and 8, the second line segment L2 is defined as the line segment that passes through an arbitrary second point D2 within the adhesive region Ra when viewed in the Z1 direction and connects the ends of the adhesive region Ra in the shortest possible path. The second point D2 is a different point from the first point D1. Similarly, as shown in Figures 7 and 9, the third line segment L3 is defined as the line segment that passes through an arbitrary third point D3 within the adhesive region Ra when viewed in the Z1 direction and connects the ends of the adhesive region Ra in the shortest possible path. The third point D3 is a different point from the first point D1 and the second point D2.

[0058] Here, at least one of the edges of the bonding region Ra is the outer edge Re_out of the bonding region Ra. The outer edge Re_out is the outermost part of the edge of the bonding region Ra. The first point D1, the second point D2, and the third point D3 are not located at the edges of the bonding region Ra. Therefore, the first line segment L1, the second line segment L2, and the third line segment L3 are not all located at the edges of the bonding region Ra. The first line segment L1 is longer than the second line segment L2 and longer than the third line segment L3. The third line segment L3 is longer than the second line segment L2.

[0059] Here, the spatial axis along the first line segment L1 is called the T-axis, the spatial axis along the second line segment L2 is called the U-axis, and the spatial axis along the third line segment L3 is called the Q-axis. Furthermore, the spatial axis perpendicular to the T-axis and Z-axis is called the R-axis, the spatial axis perpendicular to the U-axis and Z-axis is called the S-axis, and the spatial axis perpendicular to the Q-axis and Z-axis is called the P-axis. Opposite directions along the T-axis are called the T1 direction and the T2 direction, similarly, opposite directions along the U-axis are called the U1 direction and the U2 direction, and opposite directions along the Q-axis are called the Q1 direction and the Q2 direction. Similarly, opposite directions along the R-axis are called the R1 direction and the R2 direction, opposite directions along the S-axis are called the S1 direction and the S2 direction, and opposite directions along the P-axis are called the P1 direction and the P2 direction.

[0060] Furthermore, if the T1 and T2 directions are not specified, the direction along the T-axis is referred to as the T-axis direction. The T-axis direction is the direction along the first line segment L1. Similarly, if the U1 and U2 directions are not specified, the direction along the U-axis is referred to as the U-axis direction, and if the Q1 and Q2 directions are not specified, the direction along the Q-axis is referred to as the Q-axis direction. The U-axis direction is the direction along the second line segment L2, and the Q-axis direction is the direction along the third line segment L3. Similarly, if the R1 and R2 directions are not specified, the direction along the R-axis is referred to as the R-axis direction, if the S1 and S2 directions are not specified, the direction along the S-axis is referred to as the S-axis direction, and if the P1 and P2 directions are not specified, the direction along the P-axis is referred to as the P-axis direction.

[0061] From Figure 10 onward, when the vertical direction of the drawing is the Z-axis direction, the Z1 direction is shown as the downward direction of the drawing. Figures 10, 11, and 12 are cross-sectional views passing through the first line segment L1, the second line segment L2, and the third line segment L3 in Figure 7, respectively, and are cross-sectional views taken in the R1, S1, and P1 directions, respectively. Figure 13 is a cross-sectional view of line EE in Figure 7, and is a cross-sectional view taken in the T2, U2, or Q2 direction. In addition to the holder 13, Figures 10, 11, 12, and 13 also show a fixing plate 15. As shown in Figures 10, 11, 12, and 13, the holder 13 is stacked on the fixing plate 15 in the Z1 direction. The first surface 13f has a region R1 that overlaps with the first line segment L1 in the Z1 direction, a region R2 that overlaps with the second line segment L2 in the Z1 direction, and a region R3 that overlaps with the third line segment L3 in the Z1 direction. These regions are lines and do not have widths in the R-axis direction, S-axis direction, or P-axis direction, respectively.

[0062] As shown in Figure 10, the region R1 of the first surface 13f that overlaps with the first line segment L1 in the Z1 direction has two first adhesive regions R1a, which are part of the adhesive region Ra, and a first recess 13c_1 that is recessed in the Z1 direction more than the first adhesive region R1a. The first adhesive region R1a is the region that is bonded to the fixing plate 15. In other words, the adhesive 19 placed in the first adhesive region R1a is in contact with the fixing plate 15. To put it another way, the adhesive 19 is placed between the first adhesive region R1a and the fixing plate 15, and the space is filled with the adhesive 19. The first adhesive region R1a is the region of the region R1 that overlaps with the first line segment L1 in the Z1 direction that has the smallest distance Lr1 in the Z-axis direction from the fixing plate 15.

[0063] The first recess 13c_1 is configured to allow excess adhesive 19 applied to the first bonding region R1a to flow out. At least a portion of the first recess 13c_1 is not bonded to the fixing plate 15. In other words, at least a portion of the adhesive 19 placed in the first recess 13c_1 does not come into contact with the fixing plate 15. To put it another way, a space is formed between the first recess 13c_1 and the fixing plate 15 where no adhesive 19 is placed, i.e., a space not filled with adhesive 19. The first recess 13c_1 may be partially bonded to the fixing plate 15. That is, the adhesive 19 in contact with the first recess 13c_1 may also be in contact with the fixing plate 15.

[0064] The first recess 13c_1 is located in the T-axis direction with respect to the first bonding region R1a. The first bonding region R1a is located at the ends of the first recess 13c_1 in the T1 and T2 directions. In other words, the first bonding region R1a is located at both ends of the first recess 13c_1 in the T-axis direction.

[0065] As shown in Figure 11, the region R2 of the first surface 13f that overlaps with the second line segment L2 in the Z1 direction is the second bonding region R2a. The second bonding region R2a is the region that is bonded to the fixing plate 15. In other words, the adhesive 19 placed in the second bonding region R2a is in contact with the fixing plate 15. To put it another way, the adhesive 19 is placed between the second bonding region R2a and the fixing plate 15, and the space is filled with the adhesive 19.

[0066] The distance Lr2 in the Z-axis direction between the second bonding region R2a and the fixing plate 15 is greater than the distance Lr1 in the Z-axis direction between the first bonding region R1a and the fixing plate 15. That is, the thickness in the Z-axis direction of the adhesive 19 laminated in the second bonding region R2a is greater than the thickness in the Z-axis direction of the adhesive 19 laminated in the first bonding region R1a. Also, the distance Lr2 in the Z-axis direction between the second bonding region R2a and the fixing plate 15 is greater than the distance Lr3 in the Z-axis direction between the third bonding region R3a and the fixing plate 15, which will be described later. That is, the thickness in the Z-axis direction of the adhesive 19 laminated in the second bonding region R2a is greater than the thickness in the Z-axis direction of the adhesive 19 laminated in the third bonding region R3a. Note that in this embodiment, distances Lr1 and Lr3 are the same. However, they may be different.

[0067] As shown in Figure 12, the region R3 of the first surface 13f that overlaps with the third line segment L3 in the Z1 direction has a third bonding region R3a and a third recess 13c_3 that is recessed in the Z1 direction more than the third bonding region R3a. The third bonding region R3a is the region that is bonded to the fixing plate 15. In other words, the adhesive 19 placed in the third bonding region R3a is in contact with the fixing plate 15. To put it another way, the adhesive 19 is placed between the third bonding region R3a and the fixing plate 15, and the space is filled with the adhesive 19. The third bonding region R3a is the region of the region R3 that overlaps with the third line segment L3 in the Z1 direction that has the smallest distance Lr3 in the Z-axis direction from the fixing plate 15.

[0068] The third recess 13c_3 is a component for draining excess adhesive 19 from the adhesive area R3a. At least a portion of the third recess 13c_3 is not bonded to the fixing plate 15. In other words, at least a portion of the adhesive 19 placed in the third recess 13c_3 does not come into contact with the fixing plate 15. To put it another way, a space is formed between the third recess 13c_3 and the fixing plate 15 where no adhesive 19 is placed, i.e., a space not filled with adhesive 19. On the other hand, a portion of the third recess 13c_3 may be bonded to the fixing plate 15. That is, the adhesive 19 that comes into contact with the third recess 13c_3 may come into contact with the fixing plate 15.

[0069] The third recess 13c_3 is located in the Q1 direction relative to the third adhesive region R3a. However, the third recess 13c_3 may be configured to be located in the Q2 direction relative to the third adhesive region R3a. In other words, the third recess 13c_3 is located in either the Q1 direction or the Q2 direction relative to the third adhesive region R3a. That is, the third adhesive region R3a is located in the Q1 direction of the third recess 13c_3 and not in the Q2 direction of the third recess, or the third adhesive region R3a is located in the Q2 direction of the third recess 13c_3 and not in the Q1 direction of the third recess.

[0070] In the liquid spray head 10 according to this embodiment, a first recess 13c_1 is provided in the region R1 of the first surface 13f that overlaps with the first line segment L1 in the Z1 direction. As a result, excess adhesive 19 flows into the first recess 13c_1, preventing the adhesive 19 from spilling out to other locations. Similarly, a third recess 13c_3 is provided in the region R3 of the first surface 13f that overlaps with the third line segment L3 in the Z1 direction. As a result, excess adhesive 19 flows into the third recess 13c_3, preventing the adhesive 19 from spilling out to other locations. In the first surface 13f, in the region R2 that overlaps with the second line segment L2, which is shorter than the first line segment L1 and the third line segment L3, in the Z1 direction, the excess adhesive 19 can be suppressed by increasing the distance Lr2 in the Z-axis direction between the fixing plate 15 and the holder 13. In other words, in the narrow region, the distance in the Z-axis direction between the holder 13 and the fixing plate 15 is increased, and in the wide region, a recess is provided without increasing the distance in the Z-axis direction between the holder 13 and the fixing plate 15. Therefore, while minimizing the reduction in strength, it is possible to suppress the overflow of the adhesive 19 even when a narrow portion is included in a part of the bonding area Ra.

[0071] As mentioned above, the third line segment L3 is shorter than the first line segment L1, so the region R3 that overlaps with the third line segment L3 in the Z1 direction is shorter than the region R1 that overlaps with the first line segment L1 in the Z1 direction. The region R1 that overlaps with the first line segment L1 in the Z1 direction has two first adhesive regions R1a and a first recess 13c_1, while the region R3 that overlaps with the third line segment L3 in the Z1 direction has one third adhesive region R3a and a third recess 13c_3. This is because the region R3 that overlaps with the third line segment L3 in the Z1 direction has such a small length in the Q-axis direction that it is not possible to provide a third bonding region R3a at both ends of the third recess 13c_3 in the Q-axis direction. Therefore, the length of the third bonding region R3a in the Q-axis direction is smaller than the sum of the lengths of the first bonding region R1a in the T-axis direction. Also, the length Lc3 of the third recess 13c_3 in the Q-axis direction is less than or equal to the length Lc1 of the first recess 13c_1 in the T-axis direction.

[0072] As mentioned above, the second line segment L2 is shorter than the first line segment L1, so the region R2 overlapping with the second line segment L2 in the Z1 direction is shorter than the region R1 overlapping with the first line segment L1 in the Z1 direction. The region R1 overlapping with the first line segment L1 in the Z1 direction has two first adhesive regions R1a and a first recess 13c_1, while the region R2 overlapping with the second line segment L2 in the Z1 direction has one second adhesive region R2a. In this embodiment, the length of the second adhesive region R2a in the U-axis direction, i.e., the length of the second line segment L2, is shorter than the length Lc1 of the first recess 13c_1 in the T-axis direction. This is because the region R2 that overlaps with the second line segment L2 in the Z1 direction has such a small length in the U-axis direction that it is not possible to provide the first recess 13c_1 and the first bonding region R1a. Specifically, the length Lc1 in the T-axis direction of the first recess 13c_1 is 1 mm or more, and the length in the U-axis direction of the second bonding region R2a, i.e., the length of the second line segment L2, is less than 0.5 mm.

[0073] The second bonding region R2a is linear when viewed from the S-axis direction, which is perpendicular to the Z1 direction and the second line segment L2. In other words, the second bonding region R2a is not a broken line and does not contain any irregularities. This is because the length of the second bonding region R2a in the U-axis direction is too small to create any protrusions or recesses. The statement that the second bonding region R2a is linear means that the second bonding region R2a is not limited to being a straight line when viewed from the S-axis direction, but also includes cases where it has fine irregularities caused by the manufacturing process. Fine irregularities are irregularities where the distance in the Z-axis direction between the point furthest in the Z2 direction and the point furthest in the Z1 direction is 30 μm or less. However, as shown in Modification 4 described later (see Figure 20), the second bonding region R2a may have a second recess 13c_2.

[0074] As shown in Figures 6 and 7, the second bonding region R2a is located at the X-axis end of the outer wall 13w. This is because the X-axis end of the outer wall 13w needs to be narrower, for example, to allow for a high-density arrangement of nozzles. The second bonding region R2a is not located at the Y-axis end of the outer wall 13w. Furthermore, the second bonding region R2a is provided in the part of the outer wall 13w where the thickness is minimal.

[0075] Hereafter, the first line segment L1 refers not only to the first line segment L1 shown in Figure 7, but also to the line segment that overlaps with region R1 which includes multiple first adhesive regions R1a and the first recess 13c_1 located between them. The second line segment L2 refers not only to the second line segment L2 shown in Figures 7 and 8, but also to the line segment that overlaps with region R2 which includes the second adhesive region R2a that is separated from the fixing plate 15 by a distance Lr2 in the Z-axis direction. The third line segment L3 refers not only to the third line segment L3 shown in Figures 7 and 9, but also to the line segment that overlaps with region R3 which includes the third adhesive region R3a and the third recess 13c_3.

[0076] As shown in Figure 7, the first surface 13f has a region RL1 from which the first line segment L1 can be drawn, a region RL2 from which the second line segment L2 can be drawn, and a region RL3 from which the third line segment L3 can be drawn. In this embodiment, the region RL3 from which the third line segment L3 can be drawn is located at both ends in the S-axis direction relative to the region RL2 from which the second line segment L2 can be drawn. Also, in this embodiment, the region RL3 from which the third line segment L3 can be drawn is located adjacent to the region RL1 from which the first line segment L1 can be drawn. That is, in this embodiment, the region RL2 from which the second line segment L2 can be drawn is not adjacent to the region RL1 from which the first line segment L1 can be drawn. This is because the distance from the side surface Sw of the outer peripheral wall 13w to the side surface Sb of the housing section 13b or the side surface Sa of the wiring hole 13a changes gradually, rather than abruptly, along the outer edge Re_out. However, the region RL2 from which the second line segment L2 can be drawn may be adjacent to the region RL1 from which the first line segment L1 can be drawn.

[0077] As shown in Figure 10, it is preferable that at least one of the T1 direction and the T2 direction of the first recess 13c_1 is inclined. That is, it is preferable that the first recess 13c_1 has at least one of the first inclined portion Ci1_A and the first inclined portion Ci1_B, which will be described later.

[0078] The first inclined portion Ci1_A is adjacent in the T1 direction to the first adhesive region R1a that is positioned more towards the T2 direction among the two first adhesive regions R1a, and is an inclined portion that follows a direction that is a combination of the T1 direction and the Z1 direction. The first inclined portion Ci1_B is adjacent in the T2 direction to the first adhesive region R1a that is positioned more towards the T1 direction among the two first adhesive regions R1a, and is an inclined portion that follows the combined direction of the T2 direction and the Z1 direction. From this point forward, unless otherwise specified, the first inclined portion Ci1_A and the first inclined portion Ci1_B will be described as the first inclined portion Ci1.

[0079] As shown in Figure 12, it is preferable that the end of the third recess 13c_3 in the Q2 direction is also inclined. That is, it is preferable that the third recess 13c_3 is also adjacent to the third bonding region R3a in the Q1 direction and has a second inclined portion Ci2 that is aligned with a direction obtained by combining the Q1 direction and the Z1 direction. Alternatively, the third recess 13c_3 may be positioned in the Q2 direction of the third bonding region R3a. In this case, it is preferable that the third recess 13c_3 is adjacent to the third bonding region R3a in the Q2 direction and has a second inclined portion Ci2 that is aligned with a direction obtained by combining the Q2 direction and the Z1 direction. That is, it is preferable that the end of the third recess 13c_3 in the Q2 direction is inclined.

[0080] Incidentally, the side surface Sw of the outer peripheral wall 13w shown in Figures 10 and 12 is an outer peripheral surface adjacent to the first adhesive region R1a or the third adhesive region R3a, and is a surface to which the adhesive 19 is not applied. In the example shown in Figure 10, the side surface Sw is located adjacent in the T2 direction to the first adhesive region R1a that is located more in the T2 direction of the two first adhesive regions R1a. The first recess 13c_1 is located adjacent to the first adhesive region R1a that is located more in the T2 direction in the T1 direction. Furthermore, of the two first adhesive regions R1a, the side surface Sb of the housing portion 13b is adjacent to the first adhesive region R1a that is positioned more towards the T1 direction in the T1 direction. The first recess 13c_1 is adjacent to the first adhesive region R1a that is positioned more towards the T1 direction in the T2 direction. Furthermore, as shown in Figure 12, the side surface Sw of the outer peripheral wall 13w is located adjacent to the third bonding region R3a in the Q2 direction, and the third recess 13c_3 is located in the Q1 direction of the third bonding region R3a.

[0081] As shown in Figure 10, the acute angle θ1 that the first inclined portion Ci1_A makes with the T-axis is smaller than the angle θ2 that the side surface Sw of the outer peripheral wall 13w makes with a virtual line drawn in the T2 direction from the T2 end of the adhesive region Ra. Also, the acute angle θ3 that the first inclined portion Ci1_B makes with the T-axis is smaller than the angle θ4 that the side surface Sb of the housing portion 13b makes with a virtual line drawn in the T1 direction from the T1 end of the adhesive region Ra. Typically, the angle θ2 between the side surface Sw of the outer peripheral wall 13w and a virtual line drawn in the T2 direction from the end of the adhesive region Ra in the T2 direction, and the angle θ4 between the side surface Sb of the housing portion 13b and a virtual line drawn in the T1 direction from the end of the adhesive region Ra in the T1 direction, are both 90°. As shown in Figure 12, the acute angle θ5 that the second inclined portion Ci2 makes with the Q axis is smaller than the angle θ6 that the side surface Sw of the outer peripheral wall 13w makes with a virtual line drawn in the Q2 direction from the Q2 end of the adhesive region Ra. The angle θ6 that the side surface Sw of the outer peripheral wall 13w makes with a virtual line drawn in the Q2 direction from the Q2 end of the adhesive region Ra is typically 90°.

[0082] Here, when adhesive 19 applied to any surface flows out to an adjacent surface, it tends to flow out to a surface with a gentler slope. This is because a gentler slope means the surface is closer to the adhesive 19. Therefore, the acute angle θ1 that the first inclined portion Ci1_A makes with the T-axis is smaller than the angle θ2 that the side surface Sw of the outer peripheral wall 13w makes with a virtual line drawn in the T2 direction from the end of the adhesive region Ra in the T2 direction. As a result, the adhesive 19 applied to the first adhesive region R1a is more likely to flow out to the first inclined portion Ci1_A than to the side surface Sw of the outer peripheral wall 13w. Furthermore, the acute angle θ3 that the first inclined portion Ci1_B makes with the T-axis is smaller than the angle θ4 that the side surface Sb of the housing portion 13b makes with a virtual line drawn in the T1 direction from the end of the adhesive region Ra in the T1 direction. Therefore, the adhesive 19 applied to the first adhesive region R1a is more likely to flow out to the first inclined portion Ci1_B than to the side surface Sb of the housing portion 13b. Furthermore, the acute angle θ5 that the second inclined portion Ci2 makes with the Q axis is smaller than the angle θ6 that the side surface Sw of the outer peripheral wall 13w makes with a virtual line drawn in the Q2 direction from the Q2 end of the adhesive region Ra. Therefore, the adhesive 19 applied to the third adhesive region R3a is more likely to flow out into the second inclined portion Ci2 than into the side surface Sw of the outer peripheral wall 13w. Therefore, the adhesive 19 can be more easily allowed to flow out into the first recess 13c_1 or the third recess 13c_3 than into the side surface Sw of the outer peripheral wall 13w or the side surface Sb of the housing section 13b.

[0083] Here, the following methods can be considered as means to make the distance Lr2 in the Z-axis direction between the second bonding region R2a and the fixing plate 15 greater than the distance Lr1 in the Z-axis direction between the fixing plate 15 and the first bonding region R1a. Firstly, a method of cutting the fixing plate 15; secondly, a method of cutting the holder 13; and thirdly, a method of cutting both the holder 13 and the fixing plate 15. These means are similar to the means for making the distance Lr2 in the Z-axis direction between the second bonding region R2a and the fixing plate 15 greater than the distance Lr3 in the Z-axis direction between the fixing plate 15 and the third bonding region R3a. The fixing plate 15 is thinner in the Z-axis direction than the holder 13, and cutting the fixing plate 15 reduces its strength, so the second of the above three methods is preferred.

[0084] Here, as shown in Figure 13, when viewed in the Z2 direction, the second surface 15f of the fixing plate 15 has a region 15R_1 that overlaps with the first bonding region R1a, a region 15R_2 that overlaps with the second bonding region R2a, and a region 15R_3 that overlaps with the third bonding region R3a. When the second method described above is taken, that is, when the fixing plate 15 is not cut, the thickness of the fixing plate 15 in the Z-axis direction is uniform. Therefore, the region 15R_1 that overlaps with the first bonding region R1a, the region 15R_2 that overlaps with the second bonding region R2a, and the region 15R_3 that overlaps with the third bonding region R3a are all in the same position in the Z-axis direction. Furthermore, when the second method is used, the holder 13 is cut, so the first bonding region R1a is located in the Z2 direction more than the second bonding region R2a, and the third bonding region R3a is located in the Z2 direction more than the second bonding region R2a. By creating this positional relationship, the distance Lr2 in the Z-axis direction between the second bonding region R2a and the fixed plate 15 can be made larger than the distance Lr1 in the Z-axis direction between the first bonding region R1a and the fixed plate 15, and the distance Lr3 in the Z-axis direction between the third bonding region R3a and the fixed plate 15.

[0085] 1-6. Variations 1-6-1. Variation 1 Figure 14 is a schematic plan view of the holder 13 according to Modification 1, as seen in the Z1 direction. Figure 15 is a cross-sectional view passing through the first line segment L1 of Figure 14.

[0086] In the modified example 1 shown in Figures 14 and 15, the first surface 13f includes a non-adhesive region Rn_c that is not in contact with the adhesive 19. In other words, the first surface 13f has a region that is not an adhesive region Ra. In the example shown in Figure 14, there is one non-adhesive region Rn_c inside and one outside the first recess 13c_1. The non-adherent region Rn_c is represented by a sparse dot pattern, while the adhesive region Ra is represented by a dense dot pattern. As shown in Figure 14, the adhesive region Ra in Modification 1 is annular when viewed in the Z1 direction, similar to the embodiment described above (see Figure 6). That is, when viewed in the Z1 direction, the adhesive region Ra surrounds the wiring hole 13a and the housing portion 13b.

[0087] In the following section, we will describe the ends of the adhesive region Ra, which can be the ends of the first line segment L1, the second line segment L2, and the third line segment L3, in Modification Example 1. In Modification 1, one end of the adhesive region Ra lies on the outer edge Re_out, and the other end lies on the inner edge Re_in, which will be described later. That is, the first line segment L1 is located between the outer edge Re_out and the inner edge Re_in. In Figure 14, the inner edge Re_in is indicated by a dashed line. As described above, the outer edge Re_out is the outermost part of the edge of the adhesive region Ra. On the other hand, the inner edge Re_in is the edge of the adhesive region Ra to which any point having the following characteristics is located. When the shortest line segment Le_i is drawn from any point on the edge of the adhesive region Ra to the wiring hole 13a or the housing portion 13b, the line segment Le_i does not include the adhesive region Ra in between. However, the shortest line segment Le_i may have a length of 0. That is, the inner edge Re_in may coincide with the edge of the wiring hole 13a or the housing portion 13b.

[0088] For example, when the shortest line segment Le_i is drawn from point D11 shown in Figure 14 to the wiring hole 13a or housing 13b, the line segment Le_i does not include the adhesive region Ra in between. Therefore, point D11 is a point on the inner edge Re_in. Furthermore, point D12 shown in Figure 14 is located on the edge of either the wiring hole 13a or the housing portion 13b. In other words, when the shortest line segment Le_i is drawn from point D12 to either the wiring hole 13a or the housing portion 13b, the length of this line segment Le_i is 0, and it does not contain the adhesive region Ra in between. Therefore, point D12 is a point on the inner edge Re_in.

[0089] On the other hand, for example, when the shortest line segment Le_n is drawn from points D13 and D14 shown in Figure 14 to the wiring hole 13a or housing 13b, the line segment Le_n includes an adhesive region Ra in between. Therefore, the edge Re_n where points D13 and D14 are located does not correspond to the inner edge Re_in. Furthermore, the edge Re_n where points D13 and D14 are located does not correspond to the outer edge Re_out. In other words, points on edge Re_n are not the edges of the bonding region Ra.

[0090] In Figure 15, the inner edge Re_in is located at the T1 direction end of the first adhesive region R1a, which is located in the T1 direction, among the edges of the adhesive region Ra. The outer edge Re_out is located at the T2 direction end of the first adhesive region R1a, which is located in the T2 direction, among the edges of the adhesive region Ra. Among the edges of the adhesive region Ra, the edge Re_n that overlaps with the first recess 13c_1 in the Z-axis direction does not correspond to the edge of the adhesive region Ra.

[0091] 1-6-2. Variation 2 Figure 16 is a schematic plan view of the holder 13 according to the modified example 2, as seen in the Z1 direction. Figure 17 is a cross-sectional view passing through the first line segment L1 of Figure 16.

[0092] In the modified example 2 shown in Figures 16 and 17, a non-adhesive region Rn_c is located on the first surface 13f where the adhesive 19 does not come into contact. Also, when viewed in the Z1 direction, the adhesive region Ra is band-shaped rather than annular. Specifically, two adhesive regions Ra extending in the R-axis direction are arranged parallel to each other on the first surface 13f. Furthermore, in the modified example 2, the first surface 13f has protective areas Rn_b in which the adhesive 19 is not to be allowed to flow in the T1 and T2 directions relative to the adhesive area Ra. The protective areas Rn_b are, for example, the wiring holes 13a and the housing portion 13b.

[0093] In the following section, we will describe the ends of the adhesive region Ra, which can be the ends of the first line segment L1, the second line segment L2, and the third line segment L3, in modified example 2. In modified example 2, the end of the adhesive region Ra lies on the first edge Re_1, which will be described later. That is, the first line segment L1 is between the first edges Re_1 and the first edge Re_1. In Figure 16, the first edge Re_1 is shown as a dashed line. The first edge Re_1 is the edge of the adhesive region Ra on which any point having the following characteristics is located. When the shortest line segment Le_1 is drawn from any point on the edge of the adhesive region Ra to the protective region Rn_b where adhesive 19 is not to be applied, the line segment Le_1 does not contain the adhesive region Ra in between. However, the shortest line segment Le_1 drawn from the first edge Re_1 to the protective region Rn_b may have a length of 0. That is, the first edge Re_1 may coincide with the edge of the protective region Rn_b.

[0094] For example, when the shortest line segment Le_1 is drawn from point D15, shown in Figure 16, to the protected region Rn_b, the line segment Le_1 does not include the adhesive region Ra in between. Also, point D16 is located on the edge of the protected region Rn_b. Therefore, the edge on which points D15 and D16 are located is the first edge Re_1. Conversely, for example, when the shortest line segment Le_n is drawn from points D17 and D18 to the protected area Rn_b, this line segment Le_n includes the adhesive area Ra in between. Therefore, the edge Re_n where points D17 and D18 are located does not correspond to the first edge Re_1. In other words, points on edge Re_n are not the edges of the adhesive area Ra.

[0095] In Figure 17, the first edge Re_1 is located at the T1 direction end of the first adhesive region R1a located in the T1 direction, and at the T2 direction end of the first adhesive region R1a located in the T2 direction, among the edges of the adhesive region Ra. The edge Re_n that overlaps with the first recess 13c_1 in the Z-axis direction among the edges of the adhesive region Ra is not an edge of the adhesive region Ra.

[0096] 1-6-3. Variation 3 Figure 18 is a schematic plan view of the holder 13 according to the modified example 3, as seen in the Z1 direction. Figure 19 is a cross-sectional view passing through the first line segment L1 of Figure 18.

[0097] In the modified example 3 shown in Figure 18, the adhesive region Ra is strip-shaped when viewed in the Z1 direction, similar to the modified example 2. Specifically, two adhesive regions Ra extending in the R-axis direction are arranged parallel to each other on the first surface 13f. In addition, a protective region Rn_b is arranged in the T2 direction relative to the adhesive region Ra to prevent the adhesive 19 from flowing, while no protective region Rn_b is arranged in the T1 direction relative to the adhesive region Ra. The protective region Rn_b is, for example, the wiring hole 13a and the housing portion 13b.

[0098] Here, in Modification 3, we describe the ends of the adhesive region Ra that can be the ends of the first line segment L1, the second line segment L2, and the third line segment L3. In modified example 3, one end of the adhesive region Ra lies on the second edge Re_2, which will be described later, and the other end of the adhesive region Ra lies on the third edge Re_3, which will be described later. That is, the first line segment L1 is between the second edge Re_2 and the third edge Re_3. In Figure 18, the second edge Re_2 is shown as a dashed line, and the third edge Re_3 is shown as a dotted line. The second edge Re_2 is the edge of the adhesive region Ra on which any point having the following characteristics is located. When the shortest line segment Le_2 is drawn from any point on the edge of the adhesive region Ra to the protective region Rn_b on which adhesive 19 is not to be applied, the line segment Le_2 does not contain the adhesive region Ra in between.

[0099] However, the shortest line segment Le_2 drawn from the second edge Re_2 to the protected region Rn_b may have a length of 0. That is, the second edge Re_2 may coincide with the edge of the protected region Rn_b.

[0100] Here, when two edges of adhesive regions Ra face each other without an adhesive region Ra in between, such edges of adhesive regions Ra are referred to as opposing edges Re_f. The third edge Re_3 is the edge of the adhesive region Ra that is not the second edge Re_2 and is not the opposing edge Re_f.

[0101] For example, when the shortest line segment Le_2 is drawn from point D20 in Figure 18 to the protective region Rn_b, the line segment Le_2 does not include the adhesive region Ra in between. Therefore, the edge where point D20 is located is the second edge Re_2.

[0102] Conversely, if, for example, the shortest line segment Le_n is drawn from points D21 and D22 to the protected area Rn_b, then this line segment Le_n includes the adhesive area Ra in between. Therefore, the edge Re_n where points D21 and D22 are located does not correspond to the second edge Re_2. Furthermore, the edge Re_n where points D21 and D22 are located is the opposing edge Re_f. Therefore, the edge Re_n where points D21 and D22 are located does not correspond to the third edge Re_3 either. In other words, points on edge Re_n are not the edges of the bonding region Ra.

[0103] Furthermore, for example, when the shortest line segment Le_3 is drawn from point D23 to the protected area Rn_b, this line segment Le_3 includes the adhesive area Ra in between. Therefore, the edge where point D23 is located does not correspond to the second edge Re_2. Furthermore, the edge on which point D23 is located is not the opposing edge Re_f. Therefore, the edge on which point D23 is located is the third edge Re_3.

[0104] In Figure 19, the second edge Re_2 is located at the T2 direction end of the first adhesive region R1a, which is located in the T2 direction, among the edges of the adhesive region Ra. The third edge Re_3 is located at the T1 direction end of the first adhesive region R1a, which is located in the T1 direction, among the edges of the adhesive region Ra. Among the edges of the adhesive region Ra, the edge Re_n that overlaps with the first recess 13c_1 in the Z-axis direction is the opposing edge Re_f and does not correspond to the edge of the adhesive region Ra.

[0105] 1-6-4. Variation 4 As shown in the modified example 4 in Figure 20, the second adhesive region R2a may have a second recess 13c_2. That is, the second adhesive region R2a may be a polyline formed by the continuous connection of multiple line segments, or it may be a curve. However, the length Lc2 in the U-axis direction of the second recess 13c_2 is smaller than the length Lc1 in the T-axis direction of the first recess 13c_1 shown in Figure 10. Also, the length Lc2 in the U-axis direction of the second recess 13c_2 is smaller than the length Lc3 in the Q-axis direction of the third recess 13c_3 shown in Figure 12. In other words, the second bonding region R2a does not have a recess whose length in the U-axis direction is greater than or equal to the length Lc1 in the T-axis direction of the first recess 13c_1. Furthermore, the second bonding region R2a does not have a recess whose length in the U-axis direction is greater than or equal to the length Lc3 in the Q-axis direction of the third recess 13c_3. In other words, the second bonding region R2a may have a second recess 13c_2 that is smaller than the length Lc1 in the T-axis direction of the first recess 13c_1 and the length Lc3 in the Q-axis direction of the third recess 13c_3.

[0106] 1-6-5. Variation 5 In the modified example 5 shown in Figure 21, the first surface 13f has a non-adherent region Rn_c that is not in contact with the adhesive 19 and is collinear with the second adhesive region R2a. As described above, the second adhesive region R2a is a region in which the distance Lr2 in the Z-axis direction from the fixing plate 15 is greater than the distance Lr1 in the Z-axis direction from the fixing plate 15 to the first adhesive region R1a, and the distance Lr3 in the Z-axis direction from the fixing plate 15 to the third adhesive region R3a. In modified example 5, the sum of the length of the second adhesive region R2a in the U-axis direction and the length of the non-adhesive region Rn_c in the U-axis direction is smaller than the length of the third line segment L3 described above. In other words, the sum of the length of the second line segment L2 and the length of the non-adhesive region Rn_c in the U-axis direction is smaller than the length of the third line segment L3. In other words, when the length in the U-axis direction of a region on the first surface 13f is less than the length of the third line segment L3, that region may have a non-adherent region Rn_c in addition to the second adhesive region R2a.

[0107] Here, we assume a case where the combined length of the second line segment L2 and the U-axis length of the non-adherent region Rn_c is greater than the combined length of the third line segment L3. In this case, the length in the U-axis direction of the region where the second adhesive region R2a and the non-adhesive region Rn_c are provided is large enough to provide the third recess 13c_3 and the third adhesive region R3a. Nevertheless, the region will not have the third adhesive region R3a and the third recess 13c_3, but will instead have the second adhesive region R2a and the non-adhesive region Rn_c. In this configuration, the thickness of the adhesive 19 in the Z-axis direction in the second bonding region R2a is greater than the thickness of the adhesive 19 in the Z-axis direction in the third bonding region R3a, which may lead to a decrease in adhesive strength.

[0108] The above case also includes the case where the length in the U-axis direction of the region where the second adhesive region R2a and the non-adhesive region Rn_c are provided is large enough to provide the first recess 13c_1 and two first adhesive regions R1a. Nevertheless, the region will not have the first recess 13c_1 and two first adhesive regions R1a, but will have the second adhesive region R2a and the non-adhesive region Rn_c. Similarly, in this configuration, the thickness of the adhesive 19 in the Z-axis direction of the second bonding region R2a is greater than the thickness of the adhesive 19 in the Z-axis direction of the first bonding region R1a, which may lead to a decrease in adhesive strength.

[0109] On the other hand, in the modified example 5, a second adhesive region R2a and a non-adhesive region Rn_c are provided in a region only when the length in the U-axis direction of a certain region on the first surface 13f is less than the third line segment L3. When the length in the U-axis direction of that region is greater than the third line segment L3, the second adhesive region R2a and the non-adhesive region Rn_c are not provided in that region. Therefore, it is possible to suppress the leakage of adhesive 19 while suppressing a decrease in adhesive strength.

[0110] 1-6-6. Variation 6 In the embodiment described above, the holder 13 has a first surface 13f, an adhesive area Ra, a first adhesive area R1a, a second adhesive area R2a, and a first recess 13c_1, etc. However, these configurations may not be present in the holder 13 but may be present in the fixing plate 15. Furthermore, the location where the above configuration is provided is not limited to the bonding portion between the holder 13 and the fixing plate 15. For example, if the holder 13 is separated into multiple holders, the above configuration may be provided at the bonding portions between the multiple holders. Also, for example, the above configuration may be provided at the bonding portions of each element of the head tip 14.

[0111] 2. Second Embodiment 2-1. Regarding the adhesive joints of the flow path components The first embodiment described above relates to the adhesive portion between the holder 13 and the fixing plate 15, while the second embodiment relates to the adhesive portion between the first flow path member 70 and the second flow path member 80, which are members that form the flow path of the liquid injection head 10. The first flow path member 70 is, for example, the flow path substrate 14a described above, and the second flow path member 80 is, for example, the case 14h described above. Figure 22 is a plan view of the second flow channel member 80 as seen in the Z1 direction. Figure 23 is a cross-sectional view of the FF line in Figure 22 as seen in the R2 direction. Figure 23 shows the first flow channel member 70 in addition to the second flow channel member 80. Components identical to those in the first embodiment are denoted by the same reference numerals, and redundant explanations are omitted. In this embodiment, the first line segment L1 and the second line segment L2 are parallel. That is, the T-axis direction is equal to the U-axis direction, and the R-axis direction is equal to the S-axis direction.

[0112] As shown in Figure 23, the first flow channel member 70 has a first flow channel 70f, which is a through hole that penetrates the first flow channel member 70 in the Z-axis direction, and a second surface 15f, which is a surface facing the Z1 direction. The second surface 15f has an opening 70fo that defines the first flow channel 70f.

[0113] A second flow channel member 80 is stacked on the first flow channel member 70 in the Z1 direction. As shown in Figures 22 and 23, the second flow channel member 80 has a second flow channel 80f, which is a through hole that penetrates the second flow channel member 80 in the Z-axis direction, and a wall 80w that defines the second flow channel 80f. The wall 80w has a first surface 13f that faces in the Z2 direction. The first surface 13f has an opening 80fo that defines the second flow channel 80f.

[0114] Liquid flows through the first channel 70f and the second channel 80f. As shown in Figure 23, the second surface 15f of the first channel member 70 and the first surface 13f of the second channel member 80 are bonded together by the adhesive 19, thereby connecting the first channel 70f and the second channel 80f. The first surface 13f has an adhesive region Ra to which the adhesive 19 is applied. In this embodiment, the entire area of ​​the first surface 13f is the adhesive region Ra, but the first surface 13f may also have areas that are not the adhesive region Ra. As shown in Figure 22, the adhesive region Ra encircles the entire circumference of the opening 80fo of the second channel 80f in an annular shape when viewed in the Z1 direction. Therefore, the opening 70fo of the first channel 70f, the adhesive 19, and the opening 80fo of the second channel 80f are laminated without any gaps. In other words, the opening 70fo of the first channel 70f and the opening 80fo of the second channel 80f are closely connected by the adhesive 19.

[0115] Here, the direction along the opening 80fo of the second channel 80f is referred to as the circumferential direction O. The circumferential direction O is perpendicular to the Z-axis direction. In Figure 22, the circumferential direction O at the point where the first line segment L1 intersects with the opening 80fo of the second channel 80f is equal to the R-axis direction and the S-axis direction. Similarly, the circumferential direction O at the point where the second line segment L2 intersects with the opening 80fo of the second channel 80f is also equal to the R-axis direction and the S-axis direction.

[0116] The wall 80w defining the second flow path 80f has a first portion 80a1 and a second portion 80a2. In the FF line cross-section, the width of the second portion 80a2 in the U-axis direction is smaller than the width of the first portion 80a1 in the T-axis direction. That is, the width of the second portion 80a2 in the direction perpendicular to the circumferential O and Z-axis directions is smaller than the width of the first portion 80a1 in the direction perpendicular to the circumferential O and Z-axis directions. The first surface 13f of the first part 80a1 corresponds to the region RL1 (see Figure 7) from which the first line segment L1 can be drawn. That is, the first surface 13f of the first part 80a1 has two first bonding regions R1a and a first recess 13c_1. The first surface 13f of the second part 80a2 corresponds to the region RL2 (see Figure 7) from which the second line segment L2 can be drawn. That is, the first surface 13f of the second part 80a2 has a second bonding region R2a.

[0117] The wall 80w defining the second flow path 80f may have a third portion. The third portion is a portion whose width in the direction perpendicular to the circumferential direction O and the Z axis is smaller than the width of the first portion 80a1 in the direction perpendicular to the circumferential direction O and the Z axis, and larger than the width of the second portion 80a2 in the direction perpendicular to the circumferential direction O and the Z axis. In this case, the first surface 13f of the third part is the region RL3 from which the third line segment L3 can be drawn. That is, the first surface 13f of the third part 80a3 has a third bonding region R3a and a third recess 13c_3.

[0118] 3. Regarding the wording of the claims In the first and second embodiments, either the Z1 direction or the Z2 direction is an example of the "first direction". Furthermore, the U-axis direction is an example of "the direction along the second line segment L2". Furthermore, the T-axis direction is an example of "the direction along the first line segment," where the T1 direction is either "one of the directions along the first line segment" or "the other of the directions along the first line segment," and the T2 direction is either "the other of the directions along the first line segment" or "one of the directions along the first line segment."

[0119] Furthermore, in the first embodiment, the fixing plate 15 or the holder 13 is an example of a "first member," and the fixing plate 15 or the holder 13 is an example of a "second member." Here, when the fixing plate 15 is a "first member" and the holder 13 is a "second member," the Z1 direction is a "first direction," and the Z2 direction is the "opposite direction of the first direction." On the other hand, when the fixing plate 15 is a "second member" and the holder 13 is a "first member," the Z2 direction is a "first direction," and the Z1 direction is the "opposite direction of the first direction." In the second embodiment, the first flow channel member 70 is an example of the "first member," and the second flow channel member 80 is an example of the "second member." Also, the first portion 80a1 or the third portion is an example of the "first portion."

[0120] In the first and second embodiments, the first point D1 and the third point D3 are examples of "first points," the first line segment L1 and the third line segment L3 are examples of "first line segments," the first adhesive region R1a and the third adhesive region R3a are examples of "first adhesive regions," and furthermore, the first recess 13c_1 and the third recess 13c_3 are examples of "first recesses." Furthermore, the first inclined section Ci1 and the second inclined section Ci2 are examples of "inclined sections". Furthermore, region 15R_1, which overlaps with the first adhesive region R1a, and region 15R_3, which overlaps with the third adhesive region R3a, are examples of "regions that overlap with the first adhesive region." Furthermore, the liquid injection module 40 is an example of a "head unit," and the X-axis direction is an example of a "alignment direction."

[0121] 4. Summary 4-1. Summary of the First Embodiment The liquid spray head 10 according to the first embodiment will be described below.

[0122] The liquid spray head 10 comprises a fixed plate 15, a holder 13 stacked on the fixed plate 15 in the Z1 direction and having a first surface 13f, and an adhesive 19 for bonding the fixed plate 15 and the first surface 13f. The first surface 13f has an adhesive region Ra in contact with the adhesive 19. Viewed in the Z1 direction, the first line segment L1 that passes through the first point D1 in the adhesive region Ra and connects the ends of the adhesive region Ra in the shortest distance, and the third line segment L3 that passes through the third point D3 in the adhesive region Ra and connects the ends of the adhesive region Ra in the shortest distance, are longer than the second line segment L2 that passes through a second point D2 different from the first point D1 and the third point D3 in the adhesive region Ra and connects the ends of the adhesive region Ra in the shortest distance. The region R1 of the first surface 13f that overlaps with the first line segment L1 in the Z1 direction is a first adhesive region R1a, which is part of the adhesive region Ra. The first surface 13f has a first recess 13c_1 that is recessed in the Z1 direction more than the first adhesive region R1a, and the region R3 of the first surface 13f that overlaps with the third line segment L3 in the Z1 direction has a third adhesive region R3a which is part of the adhesive region Ra, and a third recess 13c_3 that is recessed in the Z1 direction more than the third adhesive region R3a, and the second adhesive region R2a of the adhesive region Ra that overlaps with the second line segment L2 in the Z1 direction has a distance Lr2 in the Z-axis direction from the fixing plate 15 that is greater than the distance Lr1 in the Z-axis direction from the fixing plate 15 and the first adhesive region R1a, and a distance Lr3 in the Z-axis direction from the fixing plate 15 and the third adhesive region R3a, and does not have a recess whose length in the U-axis direction, which is along the second line segment L2, is greater than or equal to the length Lc1 in the T-axis direction of the first recess 13c_1, and does not have a recess whose length in the U-axis direction is greater than or equal to the length Lc3 in the Q-axis direction of the third recess 13c_3.

[0123] In the liquid spray head 10, it is desirable to prevent excess adhesive 19 from spilling out outside the bonding area where the holder 13 and the fixed plate 15 are bonded. To achieve this, recesses such as a first recess 13c_1 and a third recess 13c_3 are provided in the holder 13 or the fixed plate 15 to allow the excess adhesive 19 to flow in, thereby suppressing spillage. However, in some parts of the holder 13 or the fixed plate 15, the width of the bonding area Ra is narrow, and it may not be possible to provide recesses for allowing the excess adhesive 19 to flow in. For example, bonding is necessary even in parts with a narrow width in the U-axis direction, such as the area RL2 where the second line segment L2 can be drawn. On the other hand, instead of creating a recess, overflow can also be suppressed by increasing the distance between the fixing plate 15 and the holder 13. However, this increases the thickness of the adhesive 19, which may reduce the adhesive strength. In other words, if the thickness of the adhesive 19 is increased not only in the region RL2 where the second line segment L2 can be drawn, but also in the region RL1 where the first line segment L1 can be drawn and the region RL3 where the third line segment L3 can be drawn, the adhesive strength will decrease.

[0124] With this liquid spray head 10, a first recess 13c_1 is provided in the region R1 of the first surface 13f that overlaps with the first line segment L1 in the Z1 direction. As a result, excess adhesive 19 flows into the first recess 13c_1, preventing the adhesive 19 from spilling out to other locations. Similarly, a third recess 13c_3 is provided in the region R3 of the first surface 13f that overlaps with the third line segment L3 in the Z1 direction. As a result, excess adhesive 19 flows into the third recess 13c_3, preventing the adhesive 19 from spilling out to other locations. In the first surface 13f, the region R2 that overlaps with the second line segment L2 in the Z1 direction is so narrow that it is not possible to create a recess whose length in the U-axis direction is greater than or equal to the length Lc1 in the T-axis direction of the first recess 13c_1. Furthermore, the region R2 is so narrow that it is not possible to create a recess whose length in the U-axis direction is greater than or equal to the length Lc3 in the Q-axis direction of the third recess 13c_3. In this narrow region R2 that overlaps with the second line segment L2 in the Z1 direction, the leakage of adhesive 19 can be suppressed by increasing the distance Lr2 in the Z-axis direction between the fixing plate 15 and the holder 13. In other words, in the narrow region, the distance in the Z-axis direction between the holder 13 and the fixing plate 15 is increased, and in the wide region, a recess is provided without increasing the distance in the Z-axis direction between the holder 13 and the fixing plate 15. Therefore, while minimizing the reduction in strength, it is possible to suppress the overflow of the adhesive 19 even when a narrow portion is included in a part of the bonding area Ra.

[0125] Viewed in the Z-axis direction, the first recess 13c_1 has at least one of the first inclined portion Ci1_A and the first inclined portion Ci1_B, which are described later. The first inclined portion Ci1_A is located in the first recess 13c_1 positioned in the T1 direction with respect to the first adhesive region R1a, as viewed in the Z-axis direction, and is adjacent to the first adhesive region R1a and aligns with a direction that is a combination of the T1 direction and the Z1 direction. The first inclined portion Ci1_B is located in the first recess 13c_1 positioned in the T2 direction with respect to the first adhesive region R1a, as viewed in the Z-axis direction, and is adjacent to the first adhesive region R1a and aligns with a direction that is a combination of the T2 direction and the Z1 direction. When viewed in the Z-axis direction, if the third recess 13c_3 is located in the Q1 direction relative to the third adhesive region R3a, the third recess 13c_3 is adjacent to the third adhesive region R3a and has a second inclined portion Ci2 that is aligned with the combined direction of the Q1 and Z1 directions. When viewed in the Z-axis direction, if the third recess 13c_3 is located in the Q2 direction relative to the third adhesive region R3a, the third recess 13c_3 is adjacent to the third adhesive region R3a and has a second inclined portion Ci2 that is aligned with the combined direction of the Q2 and Z1 directions.

[0126] The first recess 13c_1 has a first inclined portion Ci1 adjacent to the first bonding region R1a, and the third recess 13c_3 has a second inclined portion Ci2 adjacent to the third bonding region R3a. Therefore, compared to the case where there is no first inclined portion Ci1 or second inclined portion Ci2, the distance between the adhesive 19 and the first recess 13c_1 or third recess 13c_3 becomes shorter, making it easier for excess adhesive 19 to flow from the first bonding region R1a to the first inclined portion Ci1, or from the third bonding region R3a to the second inclined portion Ci2.

[0127] The first bonding region R1a is positioned at both ends of the first recess 13c_1 in the T-axis direction. This makes it possible to suppress the excess adhesive 19 that has flowed from the first adhesive region R1a into the first recess 13c_1 from further spilling out of the first recess 13c_1, compared to the case where the first adhesive region R1a is positioned in either the T1 direction or the T2 direction of the first recess 13c_1. For example, compared to the case where the first adhesive region R1a is positioned in the T1 direction of the first recess 13c_1 and not positioned in the T2 direction of the first recess 13c_1, it is possible to suppress the excess adhesive 19 that has flowed from the first adhesive region R1a into the first recess 13c_1 from spilling out beyond the first recess 13c_1 in the T2 direction. Furthermore, since the first adhesive region R1a is positioned at both ends in the T-axis direction of the non-adhered region included in the first recess 13c_1, the adhesive strength is increased.

[0128] The adhesive 19 placed in the first bonding region R1a and the second bonding region R2a is in contact with the fixing plate 15, while at least a portion of the adhesive 19 placed in the first recess 13c_1 and the third recess 13c_3 is not in contact with the fixing plate 15.

[0129] As a result, compared to the case where the adhesive 19 placed in the first recess 13c_1 or the third recess 13c_3 does not have a portion that does not come into contact with the fixing plate 15, excess adhesive 19 can flow into the first recess 13c_1 or the third recess 13c_3. Therefore, it is possible to suppress excess adhesive 19 from spilling out of the region R1 on the first surface 13f that overlaps with the first line segment L1 in the Z1 direction.

[0130] The width Lc1 in the T-axis direction of the first recess 13c_1 is greater than the length of the second line segment L2. Also, the width Lc3 in the Q-axis direction of the third recess 13c_3 is greater than the length of the second line segment L2. In other words, the width of the second bonding region R2a in the U-axis direction is smaller than the width Lc1 of the first recess 13c_1 in the T-axis direction. Even in such a case, by making the distance Lr2 between the second bonding region R2a and the fixing plate 15 larger than the distance Lr1 between the first bonding region R1a and the fixing plate 15, it is possible to suppress excess adhesive 19 from spilling out of the second bonding region R2a. Furthermore, the width of the second bonding region R2a in the U-axis direction is smaller than the width Lc3 of the third recess 13c_3 in the Q-axis direction. Even in such a case, by making the distance Lr2 between the second bonding region R2a and the fixing plate 15 larger than the distance Lr3 between the third bonding region R1a and the fixing plate 15, it is possible to suppress excess adhesive 19 from spilling out of the second bonding region R2a.

[0131] The second bonding region R2a is linear when viewed from a direction perpendicular to the Z1 direction and the second line segment L2.

[0132] The fixing plate 15 is a fixing plate 15 on which a head tip 14 that sprays liquid in the Z2 direction from a plurality of nozzles N arranged in the V-axis direction intersecting the Z-axis direction is fixed, and which has an exposed opening 15a that exposes the plurality of nozzles N, and the holder 13 is a holder 13 that houses the head tip 14.

[0133] Since the fixing plate 15 has exposed openings 15a that expose multiple nozzles N for spraying liquid, liquid is likely to adhere to the fixing plate 15. If excess adhesive 19 spills out from the bonding area Ra, the liquid is more likely to come into contact with the spilled adhesive 19. The adhesive 19 that comes into contact with the liquid swells, and as the adhesive 19 placed in the bonding area Ra swells, the adhesion between the holder 13 and the fixing plate 15 may be broken, and the holder 13 and the fixing plate 15 may peel off. By preventing the adhesive 19 from overflowing, it is possible to prevent the holder 13 and the fixing plate 15 from separating.

[0134] Of the second surface 15f of the fixing plate 15 facing the holder 13, the region 15R_2 that overlaps with the second adhesive region R2a when viewed in the Z2 direction, and the region 15R_1 that overlaps with the first adhesive region R1a when viewed in the Z2 direction, or the region 15R_3 that overlaps with the third adhesive region R3a when viewed in the Z2 direction, are located at the same position in the Z-axis direction.

[0135] As a means to make the distance Lr2 in the Z-axis direction between the second bonding region R2a and the fixing plate 15 greater than the distance Lr1 in the Z-axis direction between the fixing plate 15 and the first bonding region R1a, for example, the first method is to cut the fixing plate 15, the second method is to cut the holder 13, and the third method is to cut both the holder 13 and the fixing plate 15. Here, the fixing plate 15 is thinner in the Z-axis direction than the holder 13. Therefore, in the first and third methods, the fixing plate 15, which is thin, is cut, so there is a risk that the strength of the fixing plate 15 will decrease. On the other hand, in the second method, the holder 13 is cut, and the fixing plate 15, which is thin, is not cut, so it is possible to suppress the decrease in the strength of the fixing plate 15. Since the fixed plate 15 is not machined, the thickness of the fixed plate 15 is uniform, and regions 15R_1, 15R_2, and 15R_3 are in the same position in the Z-axis direction.

[0136] The third adhesive region R3a is positioned in the Q1 direction of the third recess 13c_3 and not in the Q2 direction of the third recess 13c_3, or the third adhesive region R3a is positioned in the Q2 direction of the third recess 13c_3 and not in the Q1 direction of the third recess 13c_3.

[0137] In some cases, the width of the first surface 13f in the Q-axis direction is so small that it is not possible to provide the third adhesive region R3a at both ends of the third recess 13c_3 in the Q-axis direction. Even in such cases, the third adhesive region R3a is provided at the third recess 13c_3 and one end of the third recess 13c_3 in the Q-axis direction, and the distance between the fixing plate 15 and the holder 13 is not increased. As a result, the adhesive 19 flows into the third recess 13c_3 while minimizing the reduction in strength, and it is possible to suppress the adhesive 19 from overflowing in the direction of the third adhesive region R3a in the Q-axis direction in which the third recess 13c_3 is not located.

[0138] Multiple liquid injection heads 10 are arranged in the X-axis direction to form a liquid injection module 40, and the holder 13 has an outer peripheral wall 13w that surrounds the head tip 14 when viewed in the Z-axis direction, and the second bonding region R2a is located at the X-axis end of the outer peripheral wall 13w.

[0139] In order to arrange the nozzles N at a high density, the width in the X-axis direction of the outer peripheral wall 13w of the holder 13 needs to be reduced. Therefore, by providing a second bonding region R2a in this portion, it is possible to suppress the overflow of the adhesive 19.

[0140] 4-2. Summary of the Second Embodiment The liquid spray head 10 according to the second embodiment will be described below.

[0141] The liquid spray head 10 has a first flow channel member 70 with a first flow channel 70f through which liquid flows, and a second flow channel member 80 with a second flow channel 80f through which liquid flows. The opening 70fo of the first flow channel and the opening 80fo of the second flow channel are closely connected by an adhesive 19, and the adhesive region Ra encircles the entire circumference of the opening 80fo of the second flow channel in an annular manner when viewed in the Z1 direction. The wall 80w defining the second flow channel 80f of the second flow channel member 80 is divided into a first portion 80a1 or a third portion and the opening 80 The present invention includes a second portion 80a2 whose width in the direction perpendicular to the circumferential direction O and Z1 is smaller than the width of the first portion 80a1 in the direction perpendicular to the circumferential direction O and Z1 or the width of the third portion in the direction perpendicular to the circumferential direction O and Z1, wherein the first portion 80a1 has a first adhesive region R1a and a first recess 13c_1, the third portion has a third adhesive region R3a and a third recess 13c_3, and the second portion 80a2 has a second adhesive region R2a.

[0142] When bonding the first channel member 70 and the second channel member 80, if the adhesive 19 overflows into the first channel 70f and the second channel 80f, there is a risk that the overflowing adhesive 19 will block the first channel 70f and the second channel 80f. In addition, there is a risk that air bubbles contained in the liquid flowing through the first channel 70f and the second channel 80f will accumulate in the overflowing adhesive 19. In order to suppress the overflow of the adhesive 19, increasing the distance in the Z-axis direction between the first flow channel member 70 and the second flow channel member 80 increases the surface area of ​​the adhesive 19 in contact with the liquid flowing through the first flow channel 70f and the second flow channel 80f, making the adhesive 19 more susceptible to erosion by the liquid. Therefore, it is desirable to keep the distance in the Z-axis direction between the first flow channel member 70 and the second flow channel member 80 small. Therefore, the first portion 80a1 is provided with a first adhesive region R1a and a recess 13c_1. Furthermore, the second portion 80a2, which has a smaller width in the direction intersecting the circumferential direction O and the Z-axis direction than the first portion 80a1, is provided with a second adhesive region R2a, in which the distance in the Z-axis direction between the first flow channel member 70 and the second flow channel member 80 is greater than that in the first adhesive region R1a. In other words, when the adhesive region Ra includes a narrow portion, the distance in the Z-axis direction between the first flow channel member 70 and the second flow channel member 80 is increased in the narrow portion, and the distance in the Z-axis direction between the first flow channel member 70 and the second flow channel member 80 is not increased in the wide portion. As a result, erosion of the adhesive 19 by the liquid is minimized, while the overflow of the adhesive 19 can be suppressed. Therefore, it is possible to prevent the excess adhesive 19 from blocking the first channel 70f and the second channel 80f, and to prevent air bubbles from accumulating in the excess adhesive 19. [Explanation of Symbols]

[0143] 10…Liquid spray head, 13…Holder, 13f…First surface, Ra…Adhesion area, R1a…First adhesion area, R2a…Second adhesion area, R3a…Third adhesion area, D1…First point, D2…Second point, D3…Third point, L1…First line segment, L2…Second line segment, L3…Third line segment, 13C_1…First recess, 13C_3…Third recess, Ci1…First inclined section, Ci1_A…First inclined section, Ci1 _B…First inclined section, Ci2…Second inclined section, 13w…Outer wall, 14…Head tip, 14-1…Head tip (first head tip), 14-2…Head tip (second head tip), 14-3…Head tip, 14-4…Head tip, 14-5…Head tip, 14-6…Head tip, 15…Fixing plate, 15a-1…Exposed opening (first exposed opening), 15a- 2...Exposed opening (second exposed opening), 15f...Second surface, 15R_1...Region overlapping with the first adhesive region when viewed in the Z1 direction, 15R_2...Region overlapping with the second adhesive region when viewed in the Z1 direction, 15R_3...Region overlapping with the third adhesive region when viewed in the Z1 direction, 19...Adhesive, 70...First flow channel member, 70f...First flow channel, 70fo...Opening of the first flow channel, 80...Second flow channel member, 80f...Second flow channel, 80fo...Opening of the second flow channel, 80w...Wall defining the second flow channel, 80a1...First part, 80a2...Second part, N...Nozzle, Lr1...Distance in the Z-axis direction between the fixed plate and the first adhesive region, Lr2...Distance in the Z-axis direction between the fixed plate and the second adhesive region, Lr3...Distance in the Z-axis direction between the fixed plate and the third adhesive region, Lc1...Length in the T-axis direction of the first recess, Lc3...Length in the Q-axis direction of the third recess.

Claims

1. First member and A second member is stacked in a first direction of the first member and has a first surface, An adhesive for bonding the first member and the first surface, Equipped with, The first surface has an adhesive region that is in contact with the adhesive, Viewed in the first direction, the first line segment that passes through a first point within the adhesive region and connects the ends of the adhesive region in the shortest distance is longer than the second line segment that passes through a second point different from the first point within the adhesive region and connects the ends of the adhesive region in the shortest distance. The region of the first surface that overlaps with the first line segment in the first direction has a first adhesive region which is part of the adhesive region, and a first recess which is recessed in the first direction more than the first adhesive region. The second adhesive region, which overlaps the second line segment in the first direction, does not have a recess in which the distance from the first member in the first direction is greater than the distance from the first member to the first adhesive region in the first direction, and the length in the direction along the second line segment is greater than or equal to the length of the first recess in the direction along the first line segment. A liquid spray head characterized by the following features.

2. Viewed in the first direction, the first recess is located in one direction along the first line segment with respect to the first bonding region, The first recess is adjacent to the first bonding region and has an inclined portion that follows a direction obtained by combining the first direction and the direction along the first line segment. A liquid spray head according to feature 1.

3. The first bonding region is positioned at both ends of the first recess in a direction along the first line segment. A liquid spray head according to feature 1.

4. The adhesives placed in the first and second bonding regions are in contact with the first member. Of the adhesive disposed in the first recess, at least a portion does not come into contact with the first member. A liquid spray head according to feature 1.

5. The width of the first recess in the direction along the first line segment is greater than the length of the second line segment. A liquid spray head according to feature 1.

6. The second bonding region is linear when viewed from a direction perpendicular to the first direction and the second line segment. A liquid spray head according to feature 1.

7. The first member is a fixing plate having an opening that exposes the plurality of nozzles, to which a head tip is fixed that sprays liquid in the opposite direction to the first direction from a plurality of nozzles arranged in a direction intersecting the first direction. The second member is a holder for housing the head chip. A liquid spray head according to feature 1.

8. The region of the second surface of the fixing plate facing the holder that overlaps with the second adhesive region when viewed in the opposite direction to the first direction, and the region of the second surface that overlaps with the first adhesive region when viewed in the opposite direction to the first direction, are in the same position in the first direction. A liquid spray head according to feature 7.

9. The first member has a first channel through which liquid flows, The second member has a second channel through which liquid flows, The opening of the first channel and the opening of the second channel are closely connected by the adhesive. The bonding region, when viewed in the first direction, encloses the entire circumference of the opening of the second flow channel in an annular shape. The wall defining the second flow path of the second member includes a first portion and a second portion whose width in the direction perpendicular to the circumferential direction and the first direction of the opening is smaller than the width of the first portion in the direction perpendicular to the circumferential direction and the first direction. The first portion has a first adhesive region and a first recess, The second portion has the second adhesive region A liquid spray head according to feature 1.

10. The first adhesive region is positioned relative to the first recess in one direction along the first line segment, and not in the other direction along the first line segment. A liquid spray head according to feature 1.

11. Liquid spray heads arranged in a row in the direction of alignment to constitute a head unit, The holder has an outer peripheral wall that surrounds the head tip when viewed in the first direction, The second bonding region is located at the end of the outer peripheral wall in the direction of alignment. A liquid spray head according to feature 7.

Images