Liquid spray head

Abstract

Knowing the right time to replace the liquid spray head. [Solution] The liquid spray head comprises a nozzle for spraying liquid, a first flow path member and a second flow path member that constitute a flow path communicating with the nozzle, and a first adhesive portion that liquid-tightly connects the first flow path member and the second flow path member to constitute the flow path, wherein the first flow path member has a light-transmitting portion that allows for confirmation of the degree of deterioration of the first adhesive portion from the outside of the first flow path member.

Description

Technical Field

[0001] The present invention relates to a liquid ejection head.

Background Art

[0002] Conventionally, liquid ejection heads that eject a liquid such as ink from nozzles have been widespread. For example, in Patent Document 1, it is disclosed that a plurality of flow path members constituting the flow path of a liquid ejection head are joined to each other by an adhesive, thereby hermetically connecting the flow paths formed in each of the plurality of joined flow path members.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The adhesive joining the flow path members deteriorates by contacting the liquid flowing through the flow path, and there is a risk that the liquid in the flow path leaks out of the flow path member from the joining portion. However, in the conventional technology described above, there has been a problem that the user of the liquid ejection head cannot determine when to replace the liquid ejection head.

Means for Solving the Problems

[0005] A liquid ejection head according to a preferred aspect of the present disclosure includes a nozzle that ejects a liquid, a first flow path member and a second flow path member that constitute a flow path communicating with the nozzle, and a first adhesive portion that hermetically connects the first flow path member and the second flow path member to form the flow path. The first flow path member has a light-transmissive portion having light-transmissivity for confirming the degree of deterioration of the first adhesive portion from the outside of the first flow path member.

Brief Description of the Drawings

[0006] [Figure 1] A schematic diagram showing an example configuration of the inkjet system SYS according to the first embodiment. [Figure 2] A diagram showing the configuration of the processing unit 200. [Figure 3] A block diagram showing an example configuration of inkjet printer 100. [Figure 4] Configuration diagram of inkjet printer 100. [Figure 5] Exploded perspective view of the liquid injection head 30. [Figure 6] Cross-sectional view when the liquid injection head 30 is fractured along the line IV-IV in Figure 5. [Figure 7] A magnified view of the area around the ink hole 322 shown in Figure 6. [Figure 8] Cross-sectional view when the head unit Hn is broken along the X-axis direction, passing through the wiring hole 323. [Figure 9] A schematic plan view showing the inside of head unit Hn. [Figure 10] A plan view illustrating the internal flow channel Sn within the structure. [Figure 11] Side view of the internal supply channel S1a and the internal discharge channel S2a within the structure. [Figure 12] Side view of the internal supply channel S1b and the internal discharge channel S2b within the structure. [Figure 13] A diagram illustrating the translucent section TR. [Figure 14] A diagram illustrating the translucent portion TRa in the second embodiment. [Figure 15] A diagram illustrating the translucent portion TRb in the first modified example. [Figure 16] A diagram illustrating the translucent portion TRc in the second modified example. [Figure 17] A diagram illustrating the translucent portion TRd in the third modified example. [Figure 18] A diagram illustrating the translucent parts TRe1 and TRe2 in the fourth modified example. [Figure 19] A diagram illustrating the light-transmitting portion in the fifth modified example. [Figure 20]A diagram for explaining the light-transmitting portion in the sixth modification.

Embodiments for Carrying Out the Invention

[0007] Hereinafter, embodiments for implementing the present disclosure will be described with reference to the drawings. However, in each figure, the dimensions and scales of each part are appropriately different from the actual ones. Further, the embodiments described below are preferred specific examples of the present disclosure, and thus various technically preferable limitations are imposed. However, the scope of the present disclosure is not limited to these embodiments unless there is a description specifically limiting the present disclosure in the following description.

[0008] Hereinafter, for the sake of convenience of explanation, one direction along the X-axis from an arbitrary point will be denoted as the X1 direction, and the direction opposite to the X1 direction will be denoted as the X2 direction. The X1 direction and the X2 direction are collectively referred to as the direction along the X-axis. Similarly, the directions opposite to each other along the Y-axis from an arbitrary point are denoted as the Y1 direction and the Y2 direction, and the directions opposite to each other along the Z-axis from an arbitrary point are denoted as the Z1 direction and the Z2 direction. The Y1 direction and the Y2 direction are collectively referred to as the direction along the Y-axis. The Z1 direction and the Z2 direction are collectively referred to as the direction along the Z-axis. The direction along the X-axis and the direction along the Y-axis are perpendicular to each other. The direction along the X-axis and the direction along the Z-axis are perpendicular to each other. The direction along the Y-axis and the direction along the Z-axis are perpendicular to each other. The X-Y plane including the X-axis and the Y-axis corresponds to the horizontal plane. The Z-axis is an axis along the vertical direction, the Z1 direction corresponds to the upper side in the vertical direction, and the Z2 direction corresponds to the lower side in the vertical direction. Further, looking in the direction along the Z-axis may be described as "plan view".

[0009] 1. First Embodiment 1-1. Outline of Inkjet System SYS FIG. 1 is a schematic diagram showing a configuration example of an inkjet system SYS according to the first embodiment. The inkjet system SYS is a system that provides a service for forming an image on a medium PP (to be described later) by an inkjet method. The inkjet system SYS includes an inkjet printer 100 and a processing device 200.

[0010] Here, the inkjet printer 100 is a device provided by the manufacturer of the inkjet printer 100. The inkjet printer 100 is a liquid injection device that injects ink, which is an example of a liquid. The manufacturer of the inkjet printer 100 is a merchant that manufactures the inkjet printer 100. The manufacturer of the inkjet printer 100 may be described as the "printer manufacturer". The liquid injection head 30 incorporated in the inkjet printer 100 is provided by the manufacturer of the liquid injection head 30. The manufacturer of the liquid injection head 30 is a merchant that manufactures the liquid injection head 30. Hereinafter, the manufacturer of the liquid injection head 30 may be described as the "head manufacturer". The printer manufacturer receives the liquid injection head 30 from the head manufacturer and manufactures the inkjet printer 100 by incorporating the provided liquid injection head 30 into the inkjet printer 100. The inkjet printer 100 is an example of a "liquid injection device".

[0011] FIG. 1 shows a user U who uses the inkjet printer 100. The user U is, for example, this operator when an operator belonging to the printer manufacturer uses the inkjet printer 100. Also, for example, when a third party who has received the inkjet printer 100 from the printer manufacturer uses the inkjet printer 100, this third party is the user U. The user U uses a processing device 200 in addition to the inkjet printer 100.

[0012] The inkjet printer 100 receives image data Img indicating an image from the processing device 200. The inkjet printer 100 forms an image based on the image data Img on a medium PP. Hereinafter, the process of forming an image on the medium PP may be referred to as "printing process".

[0013] The inkjet printer 100 has one head module 3 having one liquid injection head 30.

[0014] The processing unit 200 is a computer, such as a desktop or notebook computer. The processing unit 200 may also be provided as part of the inkjet printer 100.

[0015] 1-2. Regarding the malfunction of the liquid spray head 30 The liquid jet head 30 included in the inkjet printer 100 may malfunction due to aging or other reasons. One reason for the malfunction of the liquid jet head 30 is that the adhesive joint that connects the two flow path members that constitute the flow path within the liquid jet head 30 to ensure a liquid-tight connection between them may deteriorate due to prolonged contact with ink, wear from the flow rate, and / or leaching of the adhesive into the ink. This can lead to the inability to create a liquid-tight connection between the two flow path members, potentially causing ink to leak out of the flow path from the point where the connection is no longer liquid-tight. Hereinafter, the inability of the adhesive to seal the gap between the flow paths of the two flow path members may be referred to as "seal failure." When a seal failure occurs, ink may leak out of the flow path from the point where the seal failure occurred. If ink leaks out of the flow path, it may adhere to the electronic circuitry inside the liquid jet head 30, causing it to malfunction, or the inside or surrounding area of ​​the inkjet printer 100 may be contaminated with ink.

[0016] Therefore, the present invention provides a liquid spray head 30 that can detect signs of ink leakage from the liquid spray head 30 before the liquid spray head 30 malfunctions due to ink leaking out of the flow path from a point where a sealing failure has occurred. The signs of ink leakage from the liquid spray head 30 include the fact that ink will soon leak from the liquid spray head 30 and estimating the lifespan of the liquid spray head 30, that is, estimating the time when ink will likely leak from the liquid spray head 30.

[0017] 1-3. Configuration of the processing unit 200 Figure 2 shows the configuration of the processing unit 200. The processing unit 200 includes a control circuit 210, a memory circuit 220, an input device 260, and a display device 270. The control circuit 210, the memory circuit 220, the input device 260, and the display device 270 are interconnected by a bus 290 for communicating information.

[0018] The control circuit 210 includes, for example, one or more processors such as CPUs (Central Processing Units). The control circuit 210 may also include programmable logic devices such as FPGAs (Field Programmable Gate Arrays) in place of, or in addition to, the CPUs.

[0019] The memory circuit 220 is composed of a magnetic memory device or flash ROM, etc. The memory circuit 220 is readable by the control circuit 210 and stores multiple programs, including the inkjet program PM1 executed by the control circuit 210, and various information used by the control circuit 210. The memory circuit 220 includes, for example, one or more volatile memories such as RAM and one or more non-volatile memories such as ROM, EEPROM, or PROM, or both, as semiconductor memory. The inkjet program PM1 is, for example, a program that generates image data Img.

[0020] The communication device 240 is a circuit capable of communicating with the inkjet printer 100. For example, the communication device 240 is a network card such as USB (Universal Serial Bus) or Bluetooth. USB and Bluetooth are registered trademarks.

[0021] The input device 260 is a device that outputs operation information in response to user U's actions. The input device 260 is, for example, a mouse and a keyboard.

[0022] The display device 270 displays an image containing some information to the user U. The display device 270 is an organic EL (Electro-Luminescence) display, an LED (Light Emitting Diode) display, or an LCD (Liquid Crystal Display). Alternatively, the input device 260 and the display device 270 may be integrated into a single unit. An example of an integrated configuration of the input device 260 and the display device 270 is a touch panel.

[0023] 1-4. Overview of the Inkjet Printer 100 Figure 3 is a block diagram showing an example configuration of the inkjet printer 100. Figure 4 is a diagram of the inkjet printer 100's configuration. The inkjet printer 100 shown in Figure 4 is an inkjet printing device that sprays ink as droplets onto a medium PP. Ink is an example of a "liquid". The medium PP is, for example, printing paper. However, the medium PP is not limited to printing paper, and may be any material to be printed on, such as resin film or fabric.

[0024] As shown in Figures 3 and 4, the inkjet printer 100 includes a control module CM, a liquid supply system 10, a control circuit 21, a memory circuit 22, a transport mechanism 23, a moving mechanism 24, a head module 3, and a communication device 28.

[0025] The control module CM includes a power supply circuit 113 and a drive signal generation circuit 114. The power supply circuit 113 receives power from a commercial power supply (not shown) and generates various predetermined potentials. The generated potentials are supplied to various parts of the inkjet printer 100 as appropriate. In the example shown in Figure 3, the power supply circuit 113 generates a power supply potential VHV and an offset potential VBS. The offset potential VBS is supplied to the liquid jet head 30. The power supply potential VHV is supplied to the drive signal generation circuit 114, etc.

[0026] The drive signal generation circuit 114 is a circuit that generates a drive signal Com for driving the liquid injection head 30. Specifically, the drive signal generation circuit 114 includes, for example, a DA conversion circuit and an amplification circuit. In the drive signal generation circuit 114, the DA conversion circuit converts the waveform specification signal dCom from the control circuit 21 (described later) from a digital signal to an analog signal, and the amplification circuit generates the drive signal Com by amplifying the analog signal using the power supply potential VHV from the power supply circuit 113.

[0027] The liquid supply system 10 includes a liquid container 12 and a sub-tank 13. The liquid container 12 stores ink. The sub-tank 13 temporarily stores the ink supplied from the liquid container 12.

[0028] The liquid container 12 includes, for example, a cartridge that can be attached to or removed from the inkjet printer 100, a bag-shaped ink pack made of a flexible film, or an ink tank that can be refilled with ink. The liquid container 12 includes liquid containers 12a and 12b. Liquid containers 12a and 12b store, for example, inks of different colors. Liquid container 12a stores a first ink. Liquid container 12b stores, for example, a second ink of a different color from the first ink.

[0029] Subtank 13 includes subtanks 13a and 13b. Subtank 13a is connected to liquid container 12a and temporarily stores the first ink. Subtank 13b is connected to liquid container 12b and temporarily stores the second ink. A supply tube Ta_in and a discharge tube Ta_out are also connected to subtank 13a. A supply tube Tb_in and a discharge tube Tb_out are connected to subtank 13b. These tubes are connected to the head module 3. The subtank 13 supplies ink to the head module 3 and recovers ink from the head module 3. Thus, ink circulates between the subtank 13 and the head module 3.

[0030] The inks are, for example, water-based pigment inks, solvent inks, or UV-curable inks. Solvent inks are inks that contain an organic solvent. Solvent inks are inks that, after being applied to a medium PP, erode the medium PP to form a receiving layer, and fix the colorant on this receiving layer. UV-curable inks are inks that contain a UV-curing component. Hereinafter, UV-curable inks will be referred to as UV (Ultra Violet) inks. The UV-curing component contains a monomer or oligomer. UV inks are inks that, after being applied to a medium PP, are irradiated with ultraviolet light, causing the UV-curing component to harden, and fix the colorant within the film formed by the hardening of the UV-curing component.

[0031] The memory circuit 22 stores various programs, including the control program PM2 executed by the control circuit 21, and various data, such as image data Img, processed by the control circuit 21. The memory circuit 22 includes, for example, one or more volatile memories such as RAM and one or more non-volatile memories such as ROM, EEPROM, or PROM, or both, as semiconductor memory. The memory circuit 22 may be configured as part of the control circuit 21.

[0032] The transport mechanism 23 transports the medium PP along the Y-axis under the control of the control circuit 21. The moving mechanism 24 reciprocates the head module 3 along the X-axis under the control of the control circuit 21.

[0033] The moving mechanism 24 comprises a roughly box-shaped support 241 that houses the head module 3, and an endless belt 242 to which the support 241 is fixed.

[0034] The communication device 28 is a circuit capable of communicating with the processing unit 200. For example, the communication device 28 is a network card such as a USB or Bluetooth card. Alternatively, the communication device 28 may be integrated with the control circuit 21.

[0035] The head module 3 sprays ink supplied from the sub-tank 13 onto the medium PP under the control of the control circuit 21. As the medium PP is transported by the transport mechanism 23 and the support 241 moves back and forth, the head module 3 sprays ink onto the medium PP, forming an image on the surface of the medium PP. Any ink not sprayed from the head module 3 is discharged into the sub-tank 13. The head module 3 is equipped with one liquid spray head 30, but may be equipped with multiple liquid spray heads 30.

[0036] Let's return to the explanation in Figures 3 and 4. The control circuit 21 controls each element of the inkjet printer 100. The control circuit 21 includes, for example, one or more processing circuits such as a CPU or FPGA and one or more storage circuits such as semiconductor memory.

[0037] The control circuit 21 controls the operation of each part of the inkjet printer 100 by executing a program stored in the memory circuit 22. Here, the control circuit 21 generates signals such as control signal Sk1, control signal Sk2, print signal SI, and waveform specification signal dCom as signals to control the operation of each part of the inkjet printer 100.

[0038] Control signal Sk1 is a signal for controlling the drive of the moving mechanism 24. Control signal Sk2 is a signal for controlling the drive of the transport mechanism 23. Printing signal SI is a signal for controlling the drive of the liquid spray head 30. Waveform specification signal dCom is a digital signal for defining the waveform of the drive signal Com generated by the drive signal generation circuit 114.

[0039] 1-5. Overall configuration of the liquid injection head 30 Figure 5 is an exploded perspective view of the liquid injection head 30. Figure 6 is a cross-sectional view of the liquid injection head 30 when it is broken along the line IV-IV in Figure 5. The diagram in Figure 6 is a view of the cross-section of the liquid injection head 30 when it is broken along the line IV-IV, as seen in the Y2 direction. The line IV-IV is a virtual line segment that passes through the two ink holes 322 and is aligned with the X-axis direction.

[0040] As shown in Figure 5, the liquid injection head 30 comprises a housing 3α, a flow channel structure 33, a fixing plate 36, and a reinforcing plate 37. The liquid injection head 30 also has a plurality of head units H1, H2, H3, and H4. When head units H1, H2, H3, and H4 are not distinguished, they are referred to as head unit Hn. The liquid injection head 30 also includes electrical elements such as a wiring board 381, wiring members 382, ​​circuit boards 383u, and 383v. The flow channel structure 33 has a laminate 333, supply connection parts 331a, 331b, and discharge connection parts 332a, 332b. The elements of the liquid injection head 30 will be described below with reference to Figures 5 and 6.

[0041] The housing 3α shown in Figures 5 and 6 is a hollow case that houses the head unit Hn and the laminate 333. The housing 3α has a cover member 31 and a holder member 32.

[0042] The cover member 31 houses the laminate 333. The holder member 32 houses a plurality of head units Hn. In this embodiment, the holder member 32 houses four head units Hn. The holder member 32 is positioned in the Z2 direction relative to the cover member 31.

[0043] As shown in Figure 5, the cover member 31 has two first connection holes 311, two second connection holes 312, and a first hole 313. The first hole 313 is a hole through which the wiring member 382 is inserted. One of the supply connection parts 331a and 331b is inserted and fitted into each first connection hole 311. One of the discharge connection parts 332a and 332b is inserted and fitted into each second connection hole 312.

[0044] The holder member 32 has a plurality of recesses 321, a plurality of ink holes 322, and a plurality of wiring holes 323. Each recess 321 is a depression that opens in the Z2 direction. A head unit Hn is placed in each recess 321. Each ink hole 322 is a hole through which ink flows between the flow path structure 33 and the head unit Hn. Each wiring hole 323 communicates with the recess 321. Each wiring hole 323 is a hole through which the flexible substrate 51 shown in Figure 8 passes. A flexible substrate 51 is provided for each head unit Hn and is electrically connected to the head unit Hn. Also, as shown in Figure 5, the holder member 32 has a flange portion 324 for fixing the holder member 32 to the support 241.

[0045] As shown in Figure 6, the housing 3α has an upper wall portion 34 and a side wall portion 35. The side wall portion 35 has a side wall 351u and a side wall 351v.

[0046] As shown in Figure 5, the laminated body 333 of the channel structure 33 has multiple channel plates Su1, Su2, Su3, Su4, and Su5, which are referred to as channel plates Su when not distinguished. Each channel plate Su is formed, for example, by injection molding of resin, but may also be formed of metal.

[0047] The flow path plates Su1 to Su5 are bonded to each other by adhesives that form bonding sections GL12, GL23, GL34, and GL45. Flow path plate Su5 is bonded to the holder member 32 in the Z1 direction by adhesives that form bonding section GL56. In the following description, the layers formed by adhesives within the liquid injection head 30 are collectively referred to as bonding sections GL. The bonding sections GL connect the two members in a liquid-tight manner. The adhesive that forms the bonding sections GL is, for example, an epoxy-based adhesive mainly composed of epoxy resin, but a silicone-based adhesive may also be used.

[0048] The liquid injection head 30 has a flow path SF inside that communicates with the nozzle Nz. The flow path SF includes internal supply flow paths S1a, S1b, internal discharge flow paths S2a, S2b, internal supply flow paths R1a, R1b, internal discharge flow paths R2a, R2b, a first liquid storage chamber Ra, a second liquid storage chamber Rb, second communication flow paths R4a, R4b, pressure chambers Ca, Cb, and first communication flow paths R3a, R3b.

[0049] The laminate 333 has internal supply channels S1a and S1b, and internal discharge channels S2a and S2b. When the internal supply channels S1a, S1b, S2a, and S2b are not distinguished, they are referred to as internal channel Sn. Each internal channel Sn is a space formed within the laminate 333. Ink flows through each internal channel Sn. Each internal channel Sn is formed by one or both of the grooves along the XY plane provided in each of two adjacent channel plates Su, and by holes extending in the Z axis direction within the channel plate Su. Note that in Figure 6, the internal channel Sn is omitted to avoid complexity in the drawing.

[0050] Specifically, the internal supply channel S1a supplies the first ink stored in the sub-tank 13a to the multiple head units Hn. The internal supply channel S1b supplies the second ink stored in the sub-tank 13b to the multiple head units Hn. The internal discharge channel S2a discharges the first ink that was not ejected from the multiple head units Hn to the sub-tank 13a. The internal discharge channel S2b discharges the second ink that was not ejected from the multiple head units Hn to the sub-tank 13b. Each internal channel Sn may be equipped with a filter section Fa having a filter for collecting foreign matter or air bubbles mixed in the ink.

[0051] Each of the supply connection parts 331a, 331b and discharge connection parts 332a, 332b is provided in the Z1 direction of the laminate 333 and protrudes from the laminate 333 in the Z1 direction. Each of the supply connection parts 331a, 331b and discharge connection parts 332a, 332b is a connecting pipe for connecting the flow path Sn within each structure to the outside of the housing 3α.

[0052] Specifically, the supply connection section 331a is a supply pipe that supplies first ink from the sub-tank 13a to the internal supply channel S1a, and is provided with a supply port S1a_in for supplying first ink to the laminate 333. The supply connection section 331b is a supply pipe that supplies second ink from the sub-tank 13b to the internal supply channel S1b, and is provided with a supply port S1b_in for supplying second ink to the laminate 333. The discharge connection section 332a is a discharge pipe that discharges first ink from the internal discharge channel S2a to the sub-tank 13a, and is provided with a discharge port S2a_out for discharging first ink from the laminate 333. The discharge connection section 332b is a discharge pipe that discharges second ink from the internal discharge channel S2b to the sub-tank 13b, and is provided with a discharge port S2b_out for discharging second ink from the laminate 333.

[0053] The head unit Hn has internal supply channels R1a and R1b, internal discharge channels R2a and R2b, and a liquid injection section Q for ejecting ink. The first liquid storage chamber Ra, the second liquid storage chamber Rb, the second communication channels R4a and R4b, the pressure chambers Ca and Cb, and the first communication channels R3a and R3b are included in the liquid injection section Q. The channels included in the liquid injection section Q are shown in Figure 8.

[0054] In Figure 6, the detailed shape of the liquid injection unit Q is omitted to avoid complexity in the drawing. The detailed shape of the liquid injection unit Q will be described later in Figure 8. Each head unit Hn has a plurality of nozzles Nz, as shown in Figure 6. Each nozzle Nz is a through-hole that sprays ink in the Z2 direction. Specifically, each head unit Hn has a plurality of nozzles Nz that spray first ink and a plurality of nozzles Nz that spray second ink. In addition, each head unit Hn defines the in-head supply passages R1a, R1b and the in-head discharge passages R2a, R2b.

[0055] The internal supply channels R1a and R1b are channels that extend from the Z1-direction end of the head unit Hn to the liquid injection section Q. The internal discharge channels R2a and R2b are channels that extend from the liquid injection section Q to the Z1-direction end of the head unit Hn. When the internal supply channels R1a and R1b and the internal discharge channels R2a and R2b are not distinguished, they are referred to as the internal channel Rn.

[0056] The head unit Hn has a case 335 that defines the internal flow path Rn within the head.

[0057] Figure 7 is a magnified view of the area around the ink hole 322 shown in Figure 6. The flow path plate Su5 has columnar protrusions 334a and 334b ​​that project in the Z2 direction. The protrusions 334a and 334b ​​are bonded to the holder member 32 in the Z1 direction by an adhesive that forms the bonding portion GL56.

[0058] The flow path plate Su5 has flow path plate side connecting pipes 330a and 330b. The flow path plate side connecting pipes 330a and 330b are collectively referred to as the flow path plate side connecting pipe 330. The flow path plate side connecting pipe 330 protrudes from the flow path plate Su5 toward the case 335 and is inserted into the ink hole 322.

[0059] Case 335 has case-side connecting pipes 336a and 336b. Case-side connecting pipes 336a and 336b are collectively referred to as case-side connecting pipe 336. Case-side connecting pipe 336 protrudes from case 335 toward the flow path plate Su5 and is inserted into the ink hole 322.

[0060] Adhesive is applied to the top surface of the flow path plate side connecting pipe 330 and the top surface of the case side connecting pipe 336 to form the adhesive joint GL57.

[0061] The direction of ink flow in the print head supply channels R1a and R1b is in the Z2 direction. The top surface of the channel plate side connecting pipe 330 and the top surface of the case side connecting pipe 336 are perpendicular to the direction of ink flow.

[0062] Let's return to the explanation in Figures 5 and 6. As shown in Figure 5, the fixing plate 36 is a plate member for fixing a plurality of head units Hn to the holder member 32. The fixing plate 36 has a plurality of openings 361 for exposing the nozzles Nz of the plurality of head units Hn.

[0063] The reinforcing plate 37 is positioned between the holder member 32 and the fixing plate 36 and is fixed to the fixing plate 36 with adhesive. The reinforcing plate 37 has a plurality of openings 371 in which the plurality of head units Hn are positioned.

[0064] The wiring board 381 is a mounting component for electrically connecting the liquid injection head 30 to the control circuit 21 shown in Figure 4. The wiring board 381 is placed on the laminate 333. A wiring member 382 is installed on the wiring board 381. The wiring member 382 is a component for electrically connecting the liquid injection head 30 and the control circuit 21. The wiring member 382 is, for example, a connector. Note that the wiring member 382 may also be a signal cable such as an FFC (Flexible Flat Cable).

[0065] Circuit boards 383u and 383v are arranged so as to sandwich the laminate 333 and are electrically connected to the wiring board 381. Flexible circuit boards 51 mounted on head units H1 and H3 are electrically connected to circuit board 383u via an intermediate board (not shown). Flexible circuit boards 51 mounted on head units H2 and H4 are electrically connected to circuit board 383v via an intermediate board (not shown).

[0066] 1-6. Head Unit Hn Figure 8 is a cross-sectional view of the head unit Hn when it is broken along the X-axis direction, passing through the wiring hole 323. The diagram in Figure 8 is a view of the cross-section of the head unit Hn when it is broken along the X-axis direction, passing through the wiring hole 323, as seen in the Y2 direction. Figure 9 is a schematic plan view of the inside of the head unit Hn. The diagram in Figure 9 is a plan view of the inside of the head unit Hn as seen in the Z2 direction. Figures 8 and 9 each show the portion of the head unit Hn shown in Figure 6 near the fixing plate 36.

[0067] As shown in Figure 8, the head unit Hn comprises a nozzle plate 40, a communication plate 42, a pressure chamber substrate 43, a diaphragm 44, a plurality of drive elements E, a protective section 46, a compliance substrate 45, and the case 335 described above.

[0068] The nozzle plate 40, communication plate 42, pressure chamber substrate 43, and diaphragm 44 are each elongated plate-shaped members along the Y-axis. The pressure chamber substrate 43 and case 335 are positioned in the Z1 direction relative to the communication plate 42. On the other hand, the nozzle plate 40 and compliance substrate 45 are positioned in the Z2 direction relative to the communication plate 42. Furthermore, each component of the head unit Hn is joined to each other by adhesive. Although not shown in Figure 8, the layer formed by the adhesive that joins each component of the head unit Hn to each other is also included in the adhesive portion GL.

[0069] As shown in Figure 9, the multiple nozzles Nz are divided into a first nozzle row La and a second nozzle row Lb. Each of the first nozzle row La and the second nozzle row Lb is a set of multiple nozzles Nz arranged linearly along the Y axis. The first nozzle row La and the second nozzle row Lb are spaced apart from each other and aligned in the X axis direction. Here, the liquid injection unit Q has a first liquid injection unit Qa which includes multiple nozzles Nz belonging to the first nozzle row La, and a second liquid injection unit Qb which includes multiple nozzles Nz belonging to the second nozzle row Lb. The first liquid injection unit Qa injects first ink supplied from sub-tank 13a from each nozzle Nz of the first nozzle row La. The second liquid injection unit Qb injects second ink supplied from sub-tank 13b from each nozzle Nz of the second nozzle row Lb.

[0070] In the following description, the subscript 'a' is added to the symbols of elements related to the first nozzle row La, and the subscript 'b' is added to the symbols of elements related to the second nozzle row Lb. Furthermore, the elements related to the first liquid injection section Qa and the elements related to each nozzle Nz of the second liquid injection section Qb are arranged in a substantially plane-symmetrical manner. Therefore, in the following description, the elements corresponding to the first liquid injection section Qa will be explained in detail, and the explanation of the elements corresponding to the second liquid injection section Qb will be omitted as appropriate.

[0071] As shown in Figure 8, the communication plate 42 is provided with a first communication channel R3a and a second communication channel R4a. Each of the first communication channel R3a and the second communication channel R4a is provided for each nozzle Nz. The first communication channel R3a connects the nozzle Nz to the pressure chamber Ca described later. The second communication channel R4a connects the nozzle Nz to the first liquid storage chamber Ra described later. The compliance substrate 45 also constitutes a part of the wall surface of the first liquid storage chamber Ra. The compliance substrate 45 has, for example, a flexible resin film 45a and a metal plate 45b such as stainless steel.

[0072] Multiple pressure chambers Ca are provided in the pressure chamber substrate 43. Each pressure chamber Ca is a space that communicates with a nozzle Nz via a first communication channel R3a. An elastically deformable diaphragm 44 is positioned above each pressure chamber Ca. Part or all of the diaphragm 44 may be a separate component from the pressure chamber substrate 43, or it may be integrated with it. A drive element Ea is formed on the surface of the diaphragm 44 opposite to each pressure chamber Ca. Multiple drive elements Ea are arranged in a one-to-one correspondence with multiple nozzles Nz. The drive elements Ea generate energy for ejecting ink. Specifically, when a drive signal is applied to the drive element Ea, ink is ejected from the nozzle Nz. For example, the drive element Ea is a piezoelectric element that changes the volume of the pressure chamber Ca.

[0073] A protective section 46 is positioned on the diaphragm 44. A flexible substrate 51 is bonded to the surface of the diaphragm 44. Multiple wires for electrically connecting the control circuit 21 and the head unit Hn are formed on the flexible substrate 51. A drive circuit 50 for driving the drive elements E is also mounted on the flexible substrate 51. Based on the signal output from the control circuit 21, the drive circuit 50 selects whether or not to supply various signals, such as drive signals, to each piezoelectric element Ea to drive each drive element Ea.

[0074] Case 335 has a first liquid storage chamber Ra for storing ink. Case 335 also has parts of the head supply channels R1a, R1b, and R2a, R2b described above. As shown in Figure 8, the head supply channel R1a and the head discharge channel R2a are each connected to the first liquid storage chamber Ra. Also as shown in Figure 8, case 335 has a substrate hole 411 through which the flexible substrate 51 is inserted.

[0075] 1-7. Shape of the channel Sn within the structure Figure 10 is a plan view illustrating an internal flow path Sn within the structure. Figure 11 is a side view of the internal supply flow path S1a and the internal discharge flow path S2a within the internal flow path Sn through which the first ink flows. Figure 12 is a side view of the internal supply flow path S1b and the internal discharge flow path S2b within the internal flow path Sn through which the second ink flows. In Figures 11 and 12, the first liquid storage chamber Ra of each head unit Hn is indicated by the symbol "Ra / Hn", and the second liquid storage chamber Rb of each head unit Hn is indicated by the symbol "Rb / Hn". Note that the configuration of the internal flow path Sn is not limited to the following configurations.

[0076] The flow path structure 33 is provided with internal supply flow paths S1a and S1b, and internal discharge flow paths S2a and S2b, as illustrated in Figures 10, 11, and 12. The internal supply flow path S1a is a flow path from the supply port S1a_in to the internal supply flow path R1a of each head unit Hn, and the internal discharge flow path S2a is a flow path from the internal discharge flow path R2a of each head unit Hn to the discharge port S2a_out. The internal supply flow path S1b is a flow path from the supply port S1b_in to the internal supply flow path R1b of each head unit Hn, and the internal discharge flow path S2b is a flow path from the internal discharge flow path R2b of each head unit Hn to the discharge port S2b_out.

[0077] As illustrated in Figures 10 and 11, the internal supply channel S1a is a channel that includes a supply section Pa1, a connecting section Pa2, and four filter sections Fa_1-Fa_4. As illustrated in Figure 11, the supply section Pa1 is formed between the channel plates Su1 and Su2. The supply section Pa1 has a shape that extends along the Y axis. The end of the supply section Pa1 in the Y2 direction communicates with the supply port S1a_in.

[0078] As illustrated in Figures 10 and 11, the internal supply channel S1a is a channel that includes a supply section Pa1, a connecting section Pa2, and four filter sections Fa_1-Fa_4. As illustrated in Figure 11, the supply section Pa1 is formed between the channel plates Su1 and Su2. The supply section Pa1 has a shape that extends along the Y axis. The end of the supply section Pa1 in the Y2 direction communicates with the supply port S1a_in.

[0079] The connecting section Pa2 and the four filter sections Fa_1 to Fa_4 are formed between the flow path plates Su2 and Su3. The connecting section Pa2 communicates with the supply section Pa1 through a through hole formed in the flow path plate Su2. The connecting section Pa2 extends in the Y2 direction from the connection point with the supply section Pa1, and branches into two systems that communicate with the filter sections Fa_1 and Fa_3.

[0080] Filter section Fa_2 communicates with supply section Pa1 through a through-hole formed in flow path plate Su2. Filter section Fa_4 communicates with supply section Pa1 through a through-hole formed in flow path plate Su2. Each filter section Fa_1-Fa_4 communicates with the in-head supply flow path R1a of each head unit Hn through through-holes that penetrate flow path plates Su3-Su5.

[0081] As illustrated in Figures 10 and 12, the internal supply channel S1b is a channel that includes a supply section Pb1, a connecting section Pb2, and four filter sections Fb_1 to Fb_4. The supply section Pb1 is formed between the channel plates Su1 and Su2. The supply section Pb1 has a shape that extends along the Y axis. A supply port S1b_in is connected to the Y2 end of the supply section Pb1. Here, the supply sections Pa1 and Pb1 are installed side by side between the channel plates Su1 and Su2.

[0082] The connecting section Pb2 and the four filter sections Fb_1-Fb_4 are formed between the flow path plates Su2 and Su3. The connecting section Pb2 communicates with the supply section Pb1 through a through hole formed in the flow path plate Su2. The connecting section Pb2 extends in the Y1 direction from the connection point with the supply section Pb1, and branches into two systems that communicate with the filter sections Fb_2 and Fb_4. Here, the connecting section Pb2 extends in the opposite direction from the connecting section Pa2 from the connection point with the supply section Pb1.

[0083] Filter section Fb_1 communicates with supply section Pb1 through a through-hole formed in flow path plate Su2. Filter section Fb_3 communicates with supply section Pb1 through a through-hole formed in flow path plate Su2. Each filter section Fb_1-Fb_4 communicates with the in-head supply channel R1b of each head unit Hn through through-holes that penetrate flow path plates Su3-Su5.

[0084] As illustrated in Figures 10 and 11, the internal discharge channel S2a of the structure is a channel that includes a discharge section Pa3. The discharge section Pa3 is formed between the channel plate Su4 and Su5. The discharge section Pa3 has a shape that extends along the Y axis over a wider area than the supply section Pa1. The vicinity of the end of the discharge section Pa3 in the Y1 direction communicates with the discharge port S2a_out. The internal discharge channel R2a of each head unit Hn communicates with the discharge section Pa3 through a through hole that penetrates the channel plate Su5.

[0085] As illustrated in Figures 10 and 12, the internal discharge channel S2b of the structure is a channel that includes a discharge section Pb3. The discharge section Pb3 is formed between the channel plates Su3 and Su4. The discharge section Pb3 has a shape that extends along the Y-axis over a wider area than the supply section Pb1. The vicinity of the end of the discharge section Pb3 in the Y1 direction communicates with the discharge port S2b_out. The internal discharge channel R2b of each head unit Hn communicates with the discharge section Pb3 through through holes that penetrate the channel plates Su4 and Su5.

[0086] 1-8. Mechanism for detecting signs of ink leakage from the liquid spray head 30 In this embodiment, in order to detect signs of ink leakage from the flow path of the liquid spray head 30 to the outside, a translucent portion TR is provided near the adhesive portion GL that bonds the two flow path members together, in order to check the degree of deterioration of the adhesive portion GL. The pair of two flow path members can be any two members that constitute the liquid spray head 30, which form part of the flow path SF and are bonded together with some kind of adhesive. Specifically, the pair of two flow path members can be a pair of two adjacent flow path plates Su within the flow path structure 33, a pair of flow path plate Su5 and case 335, and a pair of two members that constitute the head unit Hn, which form part of the flow path SF and are bonded together with some kind of adhesive. The pairs of components within the head unit Hn are, specifically, the pair of case 335 and communication plate 42, the pair of communication plate 42 and pressure chamber substrate 43, the pair of communication plate 42 and compliance substrate 45, the pair of communication plate 42 and nozzle plate 40, and the pair of pressure chamber substrate 43 and diaphragm 44. However, in this embodiment, in order for the user U to visually check the degree of deterioration, it is preferable that the light-transmitting section TR be provided in a position that is easily visible from the outside of the liquid injection head 30, specifically in the pairs of two flow path components other than the head unit Hn of the liquid injection head 30. The light-transmitting section TR will be explained using Figure 13.

[0087] Figure 13 is a diagram illustrating the translucent section TR. Figure 13 shows an example in which a translucent section TR is provided near the supply section Pb1 of the supply channel S1b within the structure. In the following drawings, the configuration of the supply section Pb1, etc., is shown in a simplified manner. Figure 13 shows the area near the supply section Pb1 in a cross-section when the liquid injection head 30 is broken along the line aa shown in Figure 10. As can be understood from Figure 13, in the first embodiment, the surface of the flow channel plate Su2 facing the Z1 direction is indented in the Z2 direction, thereby defining the ends of the supply section Pb1 in the X1 direction, the X2 direction and the Z2 direction. In the first embodiment, the flow channel plate Su1 is an example of a "first flow channel member", the flow channel plate Su2 is an example of a "second flow channel member", and the adhesive section GL12 is an example of a "first adhesive section". The supply section Pb1 of the supply channel S1b within the structure is an example of a "flow channel". Nozzle Nz, which communicates with the supply unit Pb1, is an example of a "nozzle".

[0088] The flow channel plate Su1 has a translucent portion TR. Translucency means that the material has a thickness of 10 mm or less and a visible light transmittance of 50% or more. However, since the adhesive portion GL12 is visible through the translucent portion TR, a high transmittance is preferable. Specifically, it is preferable that the material has a thickness of 10 mm or less and a visible light transmittance of 70% or more, and more preferably 90% or more. The translucent material is formed from glass, and transparent resin materials such as transparent epoxy resin and transparent acrylic resin. Although not shown in the figures, the width of the translucent portion TR in the direction along the Y axis may be the same as the length of the supply portion Pb1 in the direction along the Y axis in a plan view, or it may be shorter than the length of the supply portion Pb1 in the direction along the Y axis. As for the manufacturing method of the flow channel plate Su1, for example, the translucent portion TR and a non-translucent resin may be integrated by insert molding, or the translucent portion TR may be bonded to the non-translucent resin with some adhesive.

[0089] The flow path plate Su1 is positioned in the Z1 direction with respect to the center C1 of the liquid injection head 30 on the Z axis as shown in Figure 6. The center C1 is the midpoint between the end of the liquid injection head 30 in the Z1 direction and the end in the Z2 direction. Furthermore, the flow path plate Su1 defines the end face of the flow path structure 33 in the direction along the Z axis. The Z1 direction is an example of a "direction opposite to the injection direction".

[0090] As can be seen from Figure 13, in plan view, the translucent portion TR is divided into an overlapping region SPX1 that overlaps with partition wall WX1, an overlapping region SPX2 that overlaps with partition wall WX2, and a non-overlapping region IPX that does not overlap with either partition wall WX1 or WX2. The non-overlapping region IPX can also be said to be the region that overlaps with the supply portion Pb1 in plan view. Partition wall WX1 is a partition wall that defines the end of the supply portion Pb1 in the X1 direction of the flow path plate Su2. Partition wall WX2 is a partition wall that defines the end of the flow path plate Su2 in the X2 direction. Note that the plan view is an example of "viewing in the stacking direction of the first flow path member and the second flow path member".

[0091] In order to directly confirm the degree of deterioration of the adhesive portion GL12, it is preferable that the translucent portion TR be made visible from outside the flow channel structure 33. Specifically, the superimposed region SPX1 is bonded to the surface SZ1 of the partition wall WX1 facing the Z1 direction by the adhesive portion GL12. The superimposed region SPX2 is bonded to the surface SZ2 of the partition wall WX2 facing the Z2 direction by the adhesive portion GL12.

[0092] The translucent portion TR has markings used as a scale to indicate the degree of deterioration of the adhesive portion GL12. Specifically, the superimposed region SPX1 has a first scale mark MR11 and a second scale mark MR12 between the first position PS11, which defines the supply portion Pb1, and the second position PS12, which does not define the supply portion Pb1, at both ends along the X axis. The first position PS11 is the position of the wall surface SX1 of the partition wall WX1 facing the X2 direction in the direction along the X axis. The second scale mark MR12 is located between the second position PS12 and the first scale mark MR11. Similarly, the superimposed region SPX2 has a first scale mark MR21 and a second scale mark MR22 between the first position PS21, which defines the supply portion Pb1, and the second position PS22, which does not define the supply portion Pb1, at both ends along the X axis. The first position PS21 is the position of the wall surface SX2 of the partition wall WX2 facing the X1 direction in the direction along the X axis. The second scale mark MR22 is located between the second position PS22 and the first scale mark MR21. In the following description, the first scale mark MR11, the second scale mark MR12, the first scale mark MR21, and the second scale mark MR12 may be collectively referred to as "scale marks". The first scale marks MR11 and MR21 are examples of "first marks", and the second scale marks MR12 and MR22 are examples of "second marks".

[0093] If the translucent portion TR is made of glass or a transparent resin material, the scale markings can be formed, for example, by laser etching. The scale markings may be points of a size that are visible from outside the flow channel structure 33, or they may be line segments of a thickness that are visible from outside the flow channel structure 33, for example, along the extending direction of the supply portion Pb1. The line segments along the extending direction of the supply portion Pb1 may be solid or dashed.

[0094] The intervals between the scale marks may or may not be equal. If the scale marks are equally spaced, the shortest distance from the first position PS11 to the first scale mark MR11, the shortest distance from the first scale mark MR11 to the second scale mark MR12, and the distance from the second scale mark MR12 to the second position PS12 are approximately equal.

[0095] To make the degree of deterioration of the adhesive portion GL12 more visible, the adhesive portion GL12 may have the property of changing color when it comes into contact with the ink in the supply portion Pb1. There are two types of discoloration when it comes into contact with ink, as shown below. The first type of discoloration is one in which the pigment of the adhesive changes when it comes into contact with ink. For example, the adhesive forming the adhesive portion GL12 may contain anthocyanin pigment. The color of anthocyanin pigment is red in acidic conditions and blue in alkaline conditions. Therefore, in the first type of discoloration, when manufacturing the liquid spray head 30, the head manufacturer forms the adhesive portion GL12 so that it is alkaline if the liquid pH of the ink is acidic. On the other hand, if the liquid pH of the ink is alkaline, the adhesive portion GL12 is formed so that it is acidic. As a result, when the adhesive portion GL12 comes into contact with the ink, the anthocyanin pigment changes color, and the adhesive portion GL12 has the property of changing color when it comes into contact with ink. The pigments that change color depending on the pH are not limited to anthocyanin pigments; flavonoid pigments may also be used.

[0096] The second mode of discoloration is one in which the adhesive portion GL12 is transparent or translucent, and ink containing a colorant penetrates into the inside of the adhesive portion GL12, causing the adhesive portion GL12 to discolor due to the colorant contained in the ink.

[0097] The rate at which the adhesive portion GL12 discolors upon contact with the ink in the supply portion Pb1 is preferably such that the discoloration occurs gradually upon contact with the ink.

[0098] However, the adhesive portion GL12 does not need to discolor even when in contact with ink. Even if the adhesive portion GL12 does not discolor, user U may determine the timing for replacing the liquid spray head 30 based on the disappearance of the traces of the adhesive portion GL12.

[0099] To allow user U to see the adhesive portion GL12, a through hole or transparent member is provided in the Z1 direction partition of the cover member 31 in the portion that overlaps with the adhesive portion GL12 when viewed along the Z axis, so that the adhesive portion GL12 can be seen from outside the liquid spray head 30 through the light-transmitting portion TR.

[0100] 1-9. Summary of the First Embodiment In the first embodiment described above, the liquid spray head 30 includes a nozzle Nz for spraying ink, flow path plates Su1 and Su2 constituting a supply section Pb1 communicating with the nozzle Nz, and an adhesive section GL12 that liquid-tightly connects the flow path plates Su1 and Su2 to constitute the supply section Pb1. The flow path plate Su1 has a translucent section TR that allows light to be seen from outside the flow path plate Su1 to check the degree of deterioration of the adhesive section GL12. According to the first embodiment, the user U can check the condition of the adhesive portion GL12 through the light-transmitting portion TR, and thus check the degree of deterioration of the adhesive portion GL12. The user U can know the point at which deterioration of the adhesive portion GL12 is detected as an appropriate time to replace the liquid spray head 30. Furthermore, by checking the degree of deterioration of the adhesive portion GL12, the liquid spray head 30 can be replaced at the appropriate time. In addition, according to this embodiment, signs of ink leakage from the liquid spray head 30 can be detected without damaging the liquid spray head 30.

[0101] Furthermore, the light-transmitting portion TR has portions that are bonded to the adhesive portion GL12, specifically, superimposed regions SPX1 and SPX2. According to the first embodiment, the superimposed regions SPX1 and SPX2 allow for direct observation of the deterioration of the adhesive portion GL12 due to the use of the liquid spray head 30, enabling the liquid spray head 30 to be replaced at an appropriate time.

[0102] Furthermore, when viewed in the Z2 direction, which is the stacking direction of the flow path plates Su1 and Su2, the translucent portion TR has a first scale mark MR11 between a first position PS11, which is the end position defining the flow path of the adhesive portion GL12, and a second position PS12, which is the end position not defining the flow path of the adhesive portion GL12. As the adhesive portion GL12 deteriorates, the end defining the flow path of the adhesive portion GL12 gradually approaches the second position PS12. Therefore, when the end defining the flow path of the adhesive portion GL12 coincides with the first scale mark MR11, it is possible to know that it is time to replace the liquid spray head 30. Thus, according to the first embodiment, the user U can use the first scale mark MR11 to determine the timing for replacing the liquid spray head 30.

[0103] Furthermore, when viewed in the Z2 direction, the translucent portion TR has a second scale mark MR12 between the second position PS12 and the first scale mark MR11. According to the first embodiment, user U can know the lifespan of the liquid spray head 30 in stages. Specifically, user U can use the liquid spray head 30 until just before it fails, while ensuring time to prepare a replacement liquid spray head 30 by the second scale mark MR12, as indicated by the first scale mark MR11. For example, when the end defining the flow path of the adhesive portion GL12 coincides with the first scale mark MR11, user U orders a liquid spray head 30 from the head manufacturer. When the end defining the flow path of the adhesive portion GL12 coincides with the first scale mark MR11, user U replaces the liquid spray head 30 with a new liquid spray head 30 obtained from the head manufacturer. In the first embodiment, the translucent portion TR has the second scale mark MR12, but it does not have to have the second scale mark MR12.

[0104] Furthermore, the adhesive portion GL12 may have the property of changing color when it comes into contact with the ink in the supply portion Pb1. According to the first embodiment, compared to an embodiment in which the adhesive portion GL12 does not have the property of discoloring due to contact with the ink in the supply portion Pb1, the user U can more easily check the degree of deterioration of the adhesive portion GL12.

[0105] Furthermore, the flow path plate Su1 is positioned in the Z1 direction with respect to the center C1 of the liquid injection head 30 on the Z axis, which is along the Z2 direction, the injection direction in which the nozzle Nz ejects ink. A support 241 is located in the Z2 direction relative to the flange portion 324 of the liquid injection head 30. In the embodiment where the flow channel plate Su1 having the translucent portion TR is positioned in the Z2 direction relative to the center C1, there is a risk that the user U will not be able to see the translucent portion TR unless the liquid injection head 30 is removed from the support 241. Therefore, according to the first embodiment, it becomes easier to check the degree of deterioration of the adhesive portion GL12 compared to the embodiment where the flow channel plate Su1 is positioned in the Z2 direction relative to the center C1.

[0106] Furthermore, the liquid injection head 30 defines a supply section Pb1 and includes a laminate 333 in which a plurality of flow path plates Su, including flow path plates Su1 and Su2, are stacked in a direction along the Z axis, with flow path plate Su1 defining the end face of the laminate 333 in a direction along the Z axis. In an embodiment where the flow channel plate Su1 having a translucent portion TR does not define an end face in the direction along the Z-axis of the laminate 333, it is necessary to visually inspect the adhesive portion GL12 from a direction perpendicular to the Z-axis. As can be seen from Figure 13, since the adhesive portion GL12 is provided along the XY plane, it is difficult to check the degree of deterioration of the adhesive portion GL12 from a direction perpendicular to the Z-axis. Therefore, according to the first embodiment, it becomes easier to check the degree of deterioration of the adhesive portion GL12 compared to an embodiment where the flow channel plate Su1 does not define an end face in the direction along the Z-axis of the laminate 333.

[0107] 2. Second Embodiment In the second embodiment, the two flow path plates Su are not bonded together, and a dummy bonding portion GLD is provided solely for the purpose of checking the degree of deterioration of the bonding portion GL12.

[0108] 2-1. Translucent part TRa in the second embodiment Figure 14 is a diagram illustrating the translucent portion TRa in the second embodiment. In the second embodiment, the liquid injection head 30a has a flow channel plate Su1a instead of the flow channel plate Su1. The flow channel plate Su1a has a translucent portion TRa instead of the translucent portion TR. A dummy adhesive portion GLD is bonded to the translucent portion TRa. Note that the dummy adhesive portion GLD is an example of the "second adhesive portion".

[0109] The translucent portion TRa has a surface TZ2 that defines the supply portion Pb1 of the flow channel plate Su1. A dummy adhesive portion GLD is bonded to surface TZ2. In the example in Figure 14, the dummy adhesive portion GLD is bonded to surface TZ2 such that it covers a portion of surface TZ2. In a plan view, the ratio of the area of ​​the dummy adhesive portion GLD to the area of ​​surface TZ2 is preferably 50% or less, and more preferably 30% or less. In the example in Figure 14, two dummy adhesive portions GLD are bonded to surface TZ2. The number of dummy adhesive portions GLD may be one or three or more. When two or more dummy adhesive portions GLD are bonded to surface TZ2, the ratio of the area of ​​the dummy adhesive portions GLD to the area of ​​surface TZ2 is the ratio of the total area of ​​all dummy adhesive portions GLD bonded to surface TZ2 to the area of ​​surface TZ2. As can be seen from Figure 14, the dummy adhesive GLD is not intended to bond the two flow channel plates Su together, but rather to directly check the degree of deterioration of the dummy adhesive GLD from outside the flow channel structure 33.

[0110] The thickness WD of the dummy adhesive section GLD along the Z-axis is shorter than the distance LSP. The distance LSP is the minimum distance from the first position PS11 to the second position PS12.

[0111] The adhesive portion GL12 and the dummy adhesive portion GLD may be formed with the same type of adhesive, or with different types of adhesive. There are two embodiments for using different types of adhesive, as shown below. Hereinafter, the first embodiment may be referred to as "first embodiment relating to adhesive," and the second embodiment may be referred to as "second embodiment relating to adhesive."

[0112] In the first embodiment of the adhesive, the liquid resistance of the dummy adhesive GLD is lower than that of the adhesive GL12. However, it is preferable that the liquid resistance of the dummy adhesive GLD is slightly lower than that of the adhesive GL12. For example, by changing the ratio of the main component to the hardener in the dummy adhesive GLD compared to the ratio of the main component to the hardener in the adhesive GL12, it is possible to create a dummy adhesive GLD with slightly reduced liquid resistance.

[0113] In a second embodiment relating to the adhesive, the dummy adhesive portion GLD has the property of discoloring upon contact with the ink in the supply portion Pb1, while the adhesive portion GL12 does not have the property of discoloring upon contact with the ink in the supply portion Pb1. The discoloration property of the dummy adhesive portion GLD may be the first discoloration mode described above, or the second discoloration mode.

[0114] Similar to the first embodiment, in order to allow the user U to see the dummy adhesive portion GLD, a through hole or transparent member is provided in the portion of the partition wall of the cover member 31 in the Z1 direction that overlaps with the dummy adhesive portion GLD when viewed along the Z axis, so that the dummy adhesive portion GLD is visible from outside the liquid spray head 30a through the light-transmitting portion TRa.

[0115] 2-2. Summary of the Second Embodiment As described above, in the liquid injection head 30a of the second embodiment, the light-transmitting portion TRa has a surface TZ2 that defines the supply portion Pb1 of the flow path plate Su1a, and a dummy adhesive portion GLD is bonded to surface TZ2. According to the second embodiment, user U can indirectly confirm the deterioration state of the adhesive portion GL12 by checking the remaining state of the dummy adhesive portion GLD. Furthermore, in the first embodiment, through holes or transparent members must be provided only in the Z1 direction partition wall of the cover member 31 where the flow path plate Su1 is bonded. On the other hand, in the second embodiment, through holes or transparent members can be provided in the Z1 direction partition wall of the cover member 31 in locations other than where the flow path plate Su1 and flow path plate Su2 are bonded, thereby improving the design flexibility of the liquid injection head 30a.

[0116] Furthermore, in the initial state of the liquid injection head 30a, the dummy adhesive portion GLD is positioned so as to cover a part of the surface TZ2. According to the second embodiment, the deterioration state of the adhesive portion GL12 can be indirectly confirmed by checking whether or not a dummy adhesive portion GLD is present.

[0117] Furthermore, the adhesive portion GL12 and the dummy adhesive portion GLD may be formed using the same type of adhesive. Since the adhesive forming the adhesive portion GL12 and the adhesive forming the dummy adhesive portion GLD are of the same type, the deterioration conditions of the adhesive portion GL12 and the dummy adhesive portion GLD can be made identical for various inks. As a result of being able to make the deterioration conditions identical, in the first embodiment, compared to the embodiment in which the adhesives are of different types, the degree of deterioration of the adhesive portion GL12 and the dummy adhesive portion GLD when in contact with ink is said to be similar. Therefore, if the dummy adhesive portion GLD deteriorates, there is a high probability that the adhesive portion GL12 has also deteriorated. Thus, according to the second embodiment, by forming the adhesive portion GL12 and the dummy adhesive portion GLD with different types of adhesives, the accuracy of estimating the deterioration state of the adhesive portion GL12 can be improved.

[0118] Furthermore, the thickness WD of the dummy adhesive section GLD is shorter than the distance LSP. As described above, it is necessary to detect signs of ink leakage from the liquid spray head 30a before ink actually leaks from the liquid spray head 30a. Therefore, from the standpoint of detecting signs of ink leakage, the timing at which the dummy adhesive part GLD disappears from the surface TZ2 must be earlier than the timing at which ink leaks from the adhesive part GL12. In the case where the adhesive part GL12 and the dummy adhesive part GLD are of the same type and the thickness WD is longer than the distance LSP, even if the length of ink penetration into the adhesive part GL12 and the length of ink penetration into the dummy adhesive part GLD are the same, there is a risk that ink may leak from the adhesive part GL12 before the dummy adhesive part GLD disappears from the surface TZ2, because the distance LSP is shorter than the thickness WD. As described above, according to the second embodiment, the dummy adhesive part GLD disappears from the surface TZ2 before ink leaks from the adhesive part GL12, so signs of ink leakage from the liquid spray head 30a can be detected before ink actually leaks from the liquid spray head 30a.

[0119] Furthermore, in the first embodiment relating to the adhesive, the liquid resistance of the dummy adhesive portion GLD is lower than that of the adhesive portion GL12. As described above, the timing at which the dummy adhesive portion GLD disappears from surface TZ2 must be earlier than the timing at which ink leaks from the adhesive portion GL12. Because the liquid resistance of the dummy adhesive portion GLD is lower than that of the adhesive portion GL12, the timing at which the dummy adhesive portion GLD disappears from surface TZ2 can be set earlier than the timing at which ink leaks from the adhesive portion GL12. Therefore, according to the second embodiment, signs of ink leakage from the liquid spray head 30a can be detected before ink actually leaks from the liquid spray head 30a.

[0120] Furthermore, in a second embodiment relating to the adhesive, the dummy adhesive portion GLD has the property of changing color upon contact with the ink in the supply portion Pb1. According to the second embodiment, compared to the embodiment in which the dummy adhesive part GLD does not discolor even when it comes into contact with the ink in the supply part Pb1, the user U can more easily check the degree of deterioration of the adhesive part GL12.

[0121] 3. Variant Each of the embodiments exemplified above can be modified in various ways. Specific examples of modifications that can be applied to each of the embodiments described above are given below. Two or more embodiments arbitrarily selected from the following examples can be merged as appropriate, provided they do not contradict each other.

[0122] 3-1. First variation In the first embodiment, the partition wall WX1 defining the end of the supply section Pb1 in the X1 direction and the partition wall WX2 defining the end of the supply section Pb1 in the X2 direction were part of the flow path plate Su2, but are not limited to this.

[0123] Figure 15 is a diagram illustrating the translucent portion TRb in the first modified example. In the first modified example, the liquid injection head 30b has a flow channel plate Su1b instead of flow channel plate Su1, and a flow channel plate Su2b instead of flow channel plate Su2. Figure 15 shows the area near the supply portion Pb1 in the cross-section when the liquid injection head 30b is broken along the line aa shown in Figure 10. As can be seen from Figure 15, in the first modified example, the surface of the flow channel plate Su1b facing the Z2 direction is indented in the Z1 direction, thereby defining the ends of the supply portion Pb1 in the X1 direction, the X2 direction and the Z1 direction.

[0124] The flow channel plate Su1b has a translucent portion TRb instead of a translucent portion TR. As can be seen from Figure 15, in plan view, the translucent portion TRb has an overlapping region SPX1b instead of an overlapping region SPX1, and an overlapping region SPX2b instead of an overlapping region SPX2. In plan view, the overlapping region SPX1b overlaps with the partition wall WX1b that defines the X1-direction end of the supply portion Pb1 in the flow channel plate Su1b. In plan view, the overlapping region SPX2b overlaps with the partition wall WX2b that defines the X2-direction end of the supply portion Pb1 in the flow channel plate Su1b. The overlapping region SPX1b is bonded to the Z1-direction oriented surface SZ1b of the flow channel plate Su2b by the adhesive portion GL12b in the first modified example. The overlapping region SPX2 is bonded to surface SZ1b by the adhesive portion GL12b.

[0125] Although Figure 15 shows a first modified example based on the first embodiment, it is also possible to apply the first modified example to the second embodiment. Similarly, the second, third, and fifth modified examples described later can also be applied to the second embodiment.

[0126] 3-2. Second Variation In the first modified example, both the partition wall WX1 defining the end of the supply section Pb1 in the X1 direction and the partition wall WX2 defining the end of the supply section Pb1 in the X2 direction were part of the flow path plate Su2, but are not limited to this.

[0127] Figure 16 is a diagram illustrating the translucent portion TRc in the second modified example. In the second modified example, the liquid injection head 30c has a flow channel plate Su1c instead of flow channel plate Su1, and a flow channel plate Su2c instead of flow channel plate Su2. Figure 16 shows the area near the supply portion Pb1 in the cross-section when the liquid injection head 30c is broken along the line aa shown in Figure 10. As can be seen from Figure 16, in the second modified example, the surface of the flow channel plate Su1c facing the Z2 direction is indented in the Z1 direction, and the surface of the flow channel plate Su1c facing the Z1 direction is indented in the Z2 direction, and the supply portion Pb1 is formed by the communication of these two indented spaces.

[0128] The flow channel plate Su1c has a translucent portion TRc instead of a translucent portion TR. As can be seen from Figure 16, in a plan view, the translucent portion TRc has an overlapping region SPX1c instead of an overlapping region SPX1, and an overlapping region SPX2c instead of an overlapping region SPX2. In a plan view, the overlapping region SPX1c overlaps with the partition wall WX1c1 that defines the X1 end of the supply portion Pb1 in the flow channel plate Su1c, and the partition wall WX1c2 that defines the X1 end of the supply portion Pb1 in the flow channel plate Su2c. In a plan view, the overlapping region SPX2c overlaps with the partition wall WX2c1 that defines the X2 end of the supply portion Pb1 in the flow channel plate Su1c, and the partition wall WX2c2 that defines the X2 end of the supply portion Pb1 in the flow channel plate Su2c.

[0129] The superimposed region SPX1c is bonded to the Z1-facing surface SZ1c of the partition wall WX1c2 of the flow channel plate Su2b by the adhesive portion GL12c in the second modified example. The superimposed region SPX2c is bonded to the Z1-facing surface SZ2c of the partition wall WX2c2 of the flow channel plate Su2c by the adhesive portion GL12c in the second modified example.

[0130] 3-3. Third Variation In each of the embodiments described above, the adhesive portion GL12 extends in a direction perpendicular to the Z-axis, but it may also extend in a direction parallel to the Z-axis.

[0131] Figure 17 is a diagram illustrating the translucent portion TRd in the third modified example. In the third modified example, the liquid injection head 30d has a flow path plate Su1d instead of flow path plate Su1, and a flow path plate Su2d instead of flow path plate Su2. Figure 16 shows a cross-section of the liquid injection head 30d when it is broken along the line aa shown in Figure 10, near the supply portion Pb1. As can be seen from Figure 17, in the third modified example, the supply portion Pb1 is defined by the wall surface SX1d of the lower protrusion TX1d facing in the X2 direction, the wall surface SX2d of the lower protrusion TX2d facing in the X1 direction, the surface SZ1d of the flow path plate Su2d facing in the Z1 direction, and the surface SZ2d of the flow path plate Su1d facing in the Z2 direction. The lower protrusions TX1d and TX2d protrude from the flow path plate Su2d in the Z1 direction.

[0132] As shown in Figure 17, the flow channel plate Su1d is provided with upper protrusions PX1d and PX2d that project in the Z2 direction. In the third modified example, the flow channel plates Su1d and Su2d are bonded together by adhesive parts GL12d1 and GL12d2 instead of adhesive part GL12. Adhesive parts GL12d1 and GL12d2 are sometimes collectively referred to as adhesive part GL12d.

[0133] Adhesive part GL12d1 adheres the upper protrusion PX1d and the lower protrusion TX1d. Furthermore, adhesive part GL12d1 adheres the surface of the upper protrusion PX1d facing in the Z2 direction to the region of surface SZ1d located in the X1 direction relative to the supply part Pb1 in a plan view. Ink enters adhesive part GL12d1 from point PK1 on the base side of the upper protrusion PX1d. Adhesive part GL12d2 adheres the upper protrusion PX2d and the lower protrusion TX2d. Furthermore, adhesive part GL12d2 adheres the surface of the upper protrusion PX2d facing in the Z2 direction to the region of surface SZ1d located in the X2 direction relative to the supply part Pb1 in a plan view. Ink enters adhesive part GL12d1 from point PK2 on the base side of the upper protrusion PX2d.

[0134] Viewed along the X-axis, the upper projection PX1d overlaps with the lower projection TX1d, and the upper projection PX2d overlaps with the lower projection TX2d. The upper projection PX1d is provided with a first scale mark MR11d and a second scale mark MR12d. Viewed along the X-axis, the first scale mark MR11d is located between point PK1 and the second scale mark MR12d. The upper projection PX2d is provided with a first scale mark MR21d and a second scale mark MR22d. Viewed along the X-axis, the first scale mark MR21d is located between point PK2 and the second scale mark MR22d.

[0135] Similar to the first embodiment, in order for the user U to be able to see the upper protrusions PX1d and PX2d, a through hole or transparent member is provided in the portion of the partition wall of the cover member 31 in the direction along the X axis in the third modified example that overlaps with the upper protrusions PX1d and PX2d when viewed in the direction along the X axis.

[0136] 3-4. Fourth variation In each of the embodiments described above, in a plan view, the portion of the flow path plate Su1 that overlaps with the supply portion Pb1 is also a translucent portion TR, but this is not limited to this.

[0137] Figure 18 is a diagram illustrating the translucent sections TRe1 and TRe2 in the fourth modified example. In the fourth modified example, the liquid injection head 30e has a flow channel plate Su1e instead of the flow channel plate Su1. Figure 18 shows a cross-section near the supply section Pb1 when the liquid injection head 30e is broken along the line aa shown in Figure 10.

[0138] The flow channel plate Su1b has a light-shielding section SH1, light-transmitting sections TRe1 and TRe2 instead of a light-transmitting section TR. In a plan view, the light-shielding section SH1 overlaps the supply section Pb1, while the light-transmitting sections TRe1 and TRe2 do not overlap the supply section Pb1. The light-shielding section SH1 does not transmit ultraviolet light. Because it does not transmit ultraviolet light, in the fourth modified example, it becomes possible to use UV ink.

[0139] 3-5. Fifth variation In each of the embodiments described above, the flow path plate Su1, which is an example of the "first flow path member," is provided with a light-transmitting portion TR, but is not limited to this.

[0140] Figure 19 is a diagram illustrating the translucent portion in the fifth modified example. In the fifth modified example, the liquid injection head 30f has a flow channel plate Su1f instead of the flow channel plate Su1, and further has a translucent member GS. In the fifth modified example, the entire translucent member GS corresponds to the "translucent portion". Figure 19 shows a cross-section of the liquid injection head 30f when it is broken along the line bb shown in Figure 10, as viewed in the X2 direction.

[0141] As shown in Figure 19, the flow path plate Su1f has an opening AP1 that opens in the Z1 direction. The light-transmitting member GS is bonded to the flow path plate Su1f by an adhesive portion GLS arranged around the opening AP1, thereby closing the opening AP1. In the Z2 direction, the area MGS of the opening AP1 is less than half the area MPb that the flow path plate Su1f defines the supply portion Pb1. Furthermore, the light-transmitting member GS is smaller than the flow path plate Su1f in the Z2 direction. In the fifth modified example, the light-transmitting member GS is an example of the "first flow path member", the flow path plate Su1f is an example of the "second flow path member", the adhesive portion GLS is an example of the "first adhesive portion", the Z1 direction is an example of the "first direction", and the Z2 direction is an example of the "second direction".

[0142] The light-transmitting member GS is a plate-like material with a substantially constant thickness. In this specification, a plate-like material with a substantially constant thickness means that the shortest thickness relative to the longest thickness is 0.8 or more, and preferably 0.9 or more. Similar to the light-transmitting part TR, the light-transmitting member GS is formed from glass, and transparent resin materials such as transparent epoxy resin and transparent acrylic resin. However, if the light-transmitting member GS is formed from glass, it is easy to achieve a substantially constant thickness.

[0143] In the fifth modified example described above, the flow path plate Su1f has an opening AP1 that opens in the Z1 direction, and the light-transmitting member GS is bonded to the flow path plate Su1f such that it closes the opening AP1 with adhesive portion GLS arranged around the opening AP1. When viewed in the second direction opposite to the first direction, the area MGS of the opening AP1 is less than half the area MPb in which the flow path plate Su1f defines the supply portion Pb1, and when viewed in the Z2 direction, the light-transmitting member GS is smaller than the flow path plate Su1f. According to the fifth modification, the translucent member GS makes it easy to focus on the area to be observed, thus making the adhesive portion GLS easier to see. Furthermore, since the translucent member GS can be miniaturized, the manufacturing cost of the liquid injection head 30f can be reduced, and the weight of the liquid injection head 30f can also be reduced. In addition, since the shape of the flow channel plate Su1f can be simplified, a highly liquid-resistant material such as glass can be used as the "first flow channel member".

[0144] The light-transmitting member GS is bonded to the flow channel plate Su1f by adhesive portions GLS arranged around the opening AP1 of the flow channel plate Su1f, thereby closing the opening AP1, and is in the form of a plate with a substantially constant thickness. According to the fifth modification, it is possible to easily form the light-transmitting member GS using a material such as glass.

[0145] Although not shown in the illustration, scale markings may be provided in the portion where the translucent member GS and the adhesive portion GLS overlap in a plan view.

[0146] Furthermore, in the fifth modification, the Z1 direction is an example of a "first direction" and the Z2 direction is an example of a "second direction," but it is not limited to these. For example, the opening AP1 may be in a direction having a component in the Z1 direction. A direction having a component in the Z1 direction is, for example, a direction that intersects the Z axis at an angle greater than 0 degrees and less than 90 degrees.

[0147] 3-6. Sixth Variation In the second embodiment, in the initial state of the liquid spray head 30a, the dummy adhesive portion GLD is positioned to cover a portion of the surface TZ2 that defines the supply portion Pb1 within the light-transmitting portion TRa, but the dummy adhesive portion GLD may be positioned to cover the entire surface TZ2.

[0148] Figure 20 is a diagram illustrating the light-transmitting portion in the sixth modified example. In the sixth modified example, the liquid injection head 30g has a flow channel plate Su1g instead of the flow channel plate Su1f, and a light-transmitting member GSg instead of the light-transmitting member GS. In the sixth modified example, the entire light-transmitting member GSg corresponds to the "light-transmitting portion".

[0149] As shown in Figure 19, the light-transmitting member GSg has a projection PT1 that protrudes in the Z2 direction. The light-transmitting member GSg is bonded to the flow path plate Su1g by adhesive portion GLSg positioned around the opening AP1, thereby closing the opening AP1. In plan view, the projection PT1 is fitted into the opening AP1. Furthermore, the Z2-direction surface TZ2g of the projection PT1 defines the supply portion Pb1. A dummy adhesive portion GLDg is positioned to completely cover the surface TZ2g. In the sixth modified example, adhesive portion GLSg is an example of a "first adhesive portion", dummy adhesive portion GLDg is an example of a "second adhesive portion", and surface TZ2g is an example of a "surface".

[0150] In the liquid spray head 30g of the seventh modified example, the dummy adhesive portion GLDg is bonded to the surface TZ2g such that it completely covers the surface TZ2g. As described above, according to the seventh modification, the deterioration state of the adhesive GLSg can be indirectly confirmed by checking whether or not a dummy adhesive GLD exists. [Explanation of Symbols]

[0151] 3…Head module, 21…Control circuit, 30,30a,30b,30c,30d,30e,30f,30g…Liquid injection head, 31…Cover member, 32…Holder member, 33…Flow channel structure, 40…Nozzle plate, 42…Communicating plate, 43…Pressure chamber substrate, 44…Diaphragm, 100…Inkjet printer, 200…Processing device, 333…Laminate, 361,371…Opening, AP1…Opening, C1…Center, CM…Control module, Ca,Cb…Pressure chamber, E,Ea…Drive element, GL,GL12,GL12b,GL12c,GL12d,GL12d1,G L12d2, GL23, GL34, GL45, GL56, GL57…Adhesive part, GLD, GLDg…Dummy adhesive part, GLS, GLSg…Adhesive part, GS, GSG…Transparent material, IPX…Non-overlapping area, LSP…Distance, La…First nozzle row, Lb…Second nozzle row, MGS, MPb…Area, MR11, MR11d…First scale mark, MR12, MR12d…Second scale mark, MR21, MR21d…First scale mark, MR22, MR22d…Second scale mark, Nz…Nozzle, PP…Medium, PS11…First position, PS12…Second position, PS21…First position, PS22…Second 2 positions, PT1...protruding part, PX1d,PX2d...upper protruding part, R1a,R1b...in-head supply channel, R2a,R2b...in-head discharge channel, R3a,R3b...first connecting channel, R4a,R4b...second connecting channel, Ra...first liquid storage chamber, Rb...second liquid storage chamber, Rn...in-head channel, S1a...in-structure supply channel, S1b...in-structure supply channel, S2a...in-structure discharge channel, S2b...in-structure discharge channel, SF...channel, SH1...light shielding part, SPX1,SPX1b,SPX1c,SPX2,SPX2b,SPX2c...overlapping region, SX1,SX1d,SX2,SX2 d...wall surface, SZ1, SZ1b, SZ1c, SZ1d, SZ2, SZ2c, SZ2d...surface, Sn...channel within the structure, Su, Su1, Su1a, Su1b, Su1c, Su1d, Su1e, Su1f, Su1g, Su2, Su2b, Su2c, Su2d, Su3, Su4, Su5...channel plate, TR, TRa, TRb, TRc, TRd, TRe1, TRe2...translucent part, TX1d, TX2d...lower protrusion, TZ2, TZ2f, TZ2g...surface, WD...thickness, WX1, WX1b, WX1c1, WX1c2, WX2, WX2b, WX2c1, WX2c2...partition wall.

Claims

1. A nozzle that sprays liquid, A first flow channel member and a second flow channel member constitute a flow channel that communicates with the nozzle, A first adhesive portion is provided to liquid-tightly connect the first flow path member and the second flow path member in order to form the aforementioned flow path, Equipped with, The first flow channel member has a light-transmitting portion that allows for confirmation of the degree of deterioration of the first adhesive portion from outside the first flow channel member. A liquid spray head characterized by the following features.

2. The light-transmitting portion has a portion that is adhered to the first adhesive portion. The liquid spray head according to feature 1.

3. Viewed in the stacking direction of the first flow channel member and the second flow channel member, the light-transmitting portion has a first mark between a first position which is the end position defining the flow channel of the first adhesive portion and a second position which is the end position not defining the flow channel of the first adhesive portion. The liquid spray head according to feature 2.

4. Viewed in the stacking direction, the light-transmitting portion has a second mark between the second position and the first mark. The liquid spray head according to feature 3.

5. The first adhesive portion has the property of changing color upon contact with the liquid in the flow path. The liquid spray head according to feature 2.

6. It is equipped with a second adhesive part, The light-transmitting portion has a surface that defines the flow path of the first flow path member, The second adhesive portion is adhered to the aforementioned surface. The liquid spray head according to feature 1.

7. The second adhesive portion is bonded to the surface such that it completely covers the surface. The liquid spray head according to feature 6.

8. The second adhesive portion is bonded to the surface such that it covers a part of the surface. The liquid spray head according to feature 6.

9. The first adhesive portion and the second adhesive portion are formed with the same type of adhesive. The liquid spray head according to feature 6.

10. The thickness of the second adhesive portion is shorter than the minimum distance between the first position, which is the end of the first adhesive portion that defines the flow path, and the second position, which is the end of the first adhesive portion that does not define the flow path. The liquid spray head according to feature 9.

11. The liquid resistance of the second adhesive portion is lower than that of the first adhesive portion. The liquid spray head according to feature 6.

12. The second adhesive portion has the property of changing color upon contact with the liquid in the flow path. The liquid spray head according to feature 6.

13. The first flow channel member is positioned in a direction opposite to the injection direction with respect to the center of the liquid injection head on an axis along the injection direction in which the nozzle ejects the liquid, The liquid spray head according to feature 1.

14. The laminate comprises a plurality of flow path members, including the first flow path member and the second flow path member, stacked in the stacking direction, defining the flow path, The first flow channel member defines the end face of the laminate in the stacking direction, The liquid spray head according to feature 1.

15. The second flow channel member has an opening that opens in the first direction, The first flow channel member is bonded to the second flow channel member by a first adhesive portion arranged around the opening, such that it closes the opening. Viewed in a second direction opposite to the first direction, the area of ​​the opening is less than or equal to half the area in which the second flow path member defines the flow path. The first flow channel member is smaller than the second flow channel member when viewed in the second direction. The liquid spray head according to feature 1.

16. The first flow channel member is bonded to the second flow channel member by a first adhesive portion arranged around the opening of the second flow channel member, such that the opening is closed, and is in the form of a plate with substantially constant thickness. The liquid spray head according to feature 1.

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