Liquid injection head and liquid injection device

Abstract

Knowing the right time to replace the liquid spray head. [Solution] The liquid spray head comprises a first flow path member that defines a portion of a flow path communicating with a plurality of nozzles, a second flow path member that defines a portion of the flow path, a first adhesive portion for liquid-tightly connecting a portion of the flow path of the first flow path member and a portion of the flow path of the second flow path member, and a second adhesive portion that defines the inner wall of the flow path and defines a detection space separated from the flow path, which is a space for detecting the degree of deterioration of the first adhesive portion.

Description

Technical Field

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[0001] The present invention relates to a liquid injection head and a liquid injection device.

Background Art

[0002] Conventionally, liquid injection heads that inject liquids such as ink from nozzles have become widespread. For example, in Patent Document 1, it is disclosed that a plurality of flow path members constituting the flow path of a liquid injection 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 may leak out of the flow path member from the joining portion. However, in the conventional technology described above, there is a problem that the user of the liquid injection head cannot determine when to replace the liquid injection head.

Means for Solving the Problems

[0005] A liquid injection head according to a preferred aspect of the present disclosure includes a plurality of nozzles that inject a liquid, a first flow path member that defines a part of a flow path communicating with the plurality of nozzles, a second flow path member that defines a part of the flow path, a first adhesive portion for hermetically connecting a part of the flow path of the first flow path member and a part of the flow path of the second flow path member, and an adhesive portion that defines an inner wall of the flow path, the adhesive portion defining a detection space that is a space for detecting the degree of deterioration of the first adhesive portion and is partitioned from the flow path.

[0006] A liquid spraying device according to a preferred embodiment of the present disclosure comprises the above-described liquid spraying head, an acquisition unit for acquiring information regarding the presence or absence of liquid in the detection space, and an estimation unit for estimating the degree of deterioration of the first adhesive portion based on the information acquired by the acquisition unit. [Brief explanation of the drawing]

[0007] [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 block diagram showing an example of the electrical configuration of the liquid injection head 30. [Figure 14] A diagram showing a timing chart to explain the operation of inkjet printer 100 during the recording period Tu. [Figure 15]Figure for explaining the detection space FA in the first embodiment. [Figure 16] Figure showing the functions of the inkjet system SYS. [Figure 17] Figure showing a flowchart indicating the operation of the inkjet system SYS. [Figure 18] Block diagram showing a configuration example of the inkjet printer 100a in the second embodiment. [Figure 19] Figure for explaining the detection space FAa. [Figure 20] Figure for explaining the detection space FAa. [Figure 21] Figure showing a flowchart indicating the operation of the inkjet system SYS in the second embodiment. [Figure 22] Block diagram showing a configuration example of the inkjet printer 100b in the third embodiment. [Figure 23] Figure for explaining the detection space FAb. [Figure 24] Figure showing a flowchart indicating the operation of the inkjet system SYS in the third embodiment. [Figure 25] Block diagram showing a configuration example of the inkjet printer 100c in the fourth embodiment. [Figure 26] Figure for explaining the detection space FAc. <000009​​​​​​​​​​​​​​​​​​ [Figure 33] A diagram illustrating the dummy individual channel RJDf in the first modified example. [Modes for carrying out the invention]

[0008] The embodiments for implementing this disclosure will be described below with reference to the drawings. However, the dimensions and scale of each part in each drawing have been appropriately altered from those of the actual parts. Furthermore, the embodiments described below are preferred examples of this disclosure and are subject to various technically preferred limitations. However, the scope of this disclosure is not limited to these embodiments unless otherwise stated in the following description.

[0009] For the sake of explanation, in the following, one direction along the X-axis from an arbitrary point will be referred to as the X1 direction, and the opposite direction will be referred to as the X2 direction. The X1 and X2 directions will be collectively referred to as the directions along the X-axis. Similarly, two opposite directions along the Y-axis from an arbitrary point will be referred to as the Y1 and Y2 directions, and two opposite directions along the Z-axis from an arbitrary point will be referred to as the Z1 and Z2 directions. The Y1 and Y2 directions will be collectively referred to as the directions along the Y-axis. The Z1 and Z2 directions will be collectively referred to as the directions along the Z-axis. The directions along the X-axis and the directions along the Y-axis are mutually orthogonal. The directions along the X-axis and the directions along the Z-axis are mutually orthogonal. The directions along the Y-axis and the directions along the Z-axis are mutually orthogonal. The XY plane, which includes the X and Y axes, corresponds to the horizontal plane. The Z-axis is an axis that runs vertically, with Z1 corresponding to the upward vertical direction and Z2 corresponding to the downward vertical direction. Viewing along the Z-axis is sometimes referred to as a "planar view."

[0010] 1. First Embodiment 1-1. Overview of the SYS Inkjet System Figure 1 is a schematic diagram showing an example configuration of the inkjet system SYS according to the first embodiment. The inkjet system SYS is a system that provides a service of forming an image on a medium PP, which will be described later, using an inkjet method. The inkjet system SYS includes an inkjet printer 100 and a processing device 200.

[0011] Here, the inkjet printer 100 is a device provided by the manufacturer of the inkjet printer 100. The inkjet printer 100 is a liquid ejection device that ejects ink, which is an example of a liquid. The manufacturer of the inkjet printer 100 is the company that manufactures the inkjet printer 100. The manufacturer of the inkjet printer 100 may be referred to as the "printer manufacturer." The liquid ejection head 30 incorporated into the inkjet printer 100 is provided by the manufacturer of the liquid ejection head 30. The manufacturer of the liquid ejection head 30 is the company that manufactures the liquid ejection head 30. Hereafter, the manufacturer of the liquid ejection head 30 may be referred to as the "head manufacturer." The printer manufacturer receives the liquid ejection head 30 from the head manufacturer and manufactures the inkjet printer 100 by incorporating the provided liquid ejection head 30 into the inkjet printer 100. The inkjet printer 100 is an example of a "liquid ejection device."

[0012] Figure 1 shows a user U who uses the inkjet printer 100. User U is, for example, an employee belonging to the printer manufacturer who uses the inkjet printer 100. Also, for example, a third party who receives the inkjet printer 100 from the printer manufacturer and uses it is also a user U. In addition to the inkjet printer 100, user U also uses the processing unit 200.

[0013] The inkjet printer 100 receives image data (Img) from the processing unit 200. The inkjet printer 100 forms an image based on the image data (Img) onto the PP medium. Hereinafter, the process of forming an image onto the PP medium may be referred to as the "printing process."

[0014] The inkjet printer 100 has one head module 3, each having one liquid ejection head 30.

[0015] 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.

[0016] 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.

[0017] 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 location where a sealing failure has occurred.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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, a maintenance mechanism 27, a communication device 28, and a generation circuit 29.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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 signals Sk1, Sk2, Sk3, print signal SI, waveform specification signal dCom, and request signal RI as signals to control the operation of each part of the inkjet printer 100.

[0039] 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. Control signal Sk3 is a signal for controlling the maintenance mechanism 27. 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.

[0040] The generation circuit 29 is a circuit that generates residual vibration information (NEI) which is acquired for purposes such as identifying injection abnormalities in the liquid injection head 30. The generation circuit 29 will be described later with reference to Figure 16.

[0041] The inkjet printer 100 performs a cleaning process to restore the liquid jetting abnormality of the liquid jetting head 30 using a maintenance mechanism 27. The cleaning process includes a flushing process to discharge ink from the nozzle Nz (described later), a wiping process to wipe away foreign matter such as paper dust attached near the nozzle Nz using a wiper 272, and a pumping process to suck up ink and air bubbles from inside the nozzle Nz using a tube pump. The flushing process is a process that forcibly removes thickened ink and air bubbles mixed in the ink by repeatedly driving a piezoelectric element E (described later) with a drive signal Com for the flushing process. The maintenance mechanism 27 includes a cap 271 to cover the liquid jetting head 30 so that the nozzle Nz is sealed, a wiper 272, a tube pump (not shown) for sucking up ink and air bubbles, and an ink receiving unit (not shown) for receiving the discharged ink when the ink is discharged. The maintenance mechanism 27 is located in an area that does not overlap with the media PP when viewed in the Z-axis direction.

[0042] As shown in Figure 3, the liquid spray head 30 is provided with a detection space FA used to detect signs of ink leakage from the liquid spray head 30. The detection space FA will be described later with reference to Figure 18.

[0043] 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.

[0044] 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 and 331b, and discharge connection parts 332a and 332b. The elements of the liquid injection head 30 will be described below with reference to Figures 5 and 6.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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 recess 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 324 for fixing the holder member 32 to the support 241.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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. Note that the flow path SF is an example of a "flow path communicating with the nozzle".

[0053] 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.

[0054] 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 filter sections Fa and Fb, which have filters for collecting foreign matter or air bubbles mixed in the ink.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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 2N nozzles Nz, as shown in Figure 6. N is an integer of 2 or more. Each nozzle Nz is a through-hole that sprays ink in the Z2 direction. Specifically, each head unit Hn has N nozzles Nz that spray first ink and N nozzles Nz that spray second ink. In addition, each head unit Hn defines the internal supply channels R1a, R1b and internal discharge channels R2a, R2b.

[0059] 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.

[0060] The head unit Hn has a case 335 that defines the internal flow path Rn within the head.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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).

[0069] 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).

[0070] 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.

[0071] 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, 2N piezoelectric elements E, a protective section 46, a compliance substrate 45, and the case 335 described above. Note that the piezoelectric elements E are an example of "driving elements".

[0072] 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.

[0073] As shown in Figure 9, the 2N 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 N 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 containing N nozzles Nz belonging to the first nozzle row La, and a second liquid injection unit Qb containing N 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.

[0074] 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.

[0075] Furthermore, in the following description, a nozzle Nz assigned to the first nozzle row La may be referred to as nozzle Nz[an1], and a nozzle Nz assigned to the second nozzle row Lb may be referred to as nozzle Nz[bn2]. n1 and n2 are integers between 1 and N, inclusive. Also, below, nozzles [a1] to nozzle Nz[aN] and nozzle Nz[b1] to nozzle Nz[bN] may be referred to simply as nozzle Nz without distinction. Furthermore, elements related to nozzle Nz[p1n1] may be referred to with the prefix [p1n1]. p1 is either a or b. For example, a pressure chamber C communicating with nozzle Nz[p1n1] may be referred to as pressure chamber C[p1n1], and a piezoelectric element E that applies pressure to pressure chamber C[p1n1] may be referred to as piezoelectric element E[p1n1].

[0076] The first liquid injection unit Qa has N individual flow channels RJa, each communicating with one of the N nozzles Nz, and a first liquid storage chamber Ra, which is connected in common to the N individual flow channels RJa. Each individual flow channel RJa is formed from a second communication channel R4a, a pressure chamber Ca, and a first communication channel R3a. Ink flows into the individual flow channel RJa from the opening 37Ka, which is the Z2 end of the second communication channel R4a. The first liquid storage chamber Ra and the second liquid storage chamber Rb are examples of "common liquid chambers". When the first liquid storage chamber Ra corresponds to a "common liquid chamber", the N individual flow channels RJa correspond to "multiple individual flow channels", and when the second liquid storage chamber Rb corresponds to a "common liquid chamber", the N individual flow channels RJb correspond to "multiple individual flow channels".

[0077] 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.

[0078] The pressure chamber substrate 43 is provided with 2N pressure chambers Ca. Each pressure chamber Ca is a space that communicates with the 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 piezoelectric element Ea is formed on the surface of the diaphragm 44 opposite to each pressure chamber Ca. The N piezoelectric elements Ea are arranged in a one-to-one correspondence with the N nozzles Nz. The piezoelectric elements Ea generate energy for ejecting ink. Specifically, when the drive signal is applied, the piezoelectric elements Ea change the volume of the pressure chamber Ca, causing ink to be ejected from the nozzle Nz.

[0079] The piezoelectric element E is a laminate (not shown) with a piezoelectric material interposed between an upper electrode to which an offset potential VBS is supplied and a lower electrode to which a drive signal Com is supplied. The piezoelectric element E is, for example, the portion where the lower electrode, upper electrode, and piezoelectric material overlap when viewed from the Z1 direction. A pressure chamber Ca is provided in the Z2 direction of the piezoelectric element E. In the first embodiment, the offset potential VBS is supplied to the upper electrode and the drive signal Com is supplied to the lower electrode, but it is also possible that the drive signal Com is supplied to the upper electrode and the offset potential VBS is supplied to the lower electrode.

[0080] In the first embodiment, the lower electrodes are individual electrodes arranged spaced apart from each other for each piezoelectric element E. On the other hand, the upper electrodes are a strip-shaped common electrode that extends along the Y-axis so as to be continuous across N piezoelectric elements E.

[0081] The piezoelectric material is composed of a piezoelectric material such as lead zirconate titanate (Pb(Zr,Ti)O3) and, for example, is a strip-shaped material extending along the Y-axis so as to be continuous across N piezoelectric elements E. However, the piezoelectric material may be a single unit across the N piezoelectric elements Ea. In this case, the piezoelectric material is provided with through-holes extending along the X-axis in regions corresponding to the gaps between adjacent pressure chambers Ca in a plan view. When the diaphragm 44 vibrates in conjunction with the deformation of the piezoelectric elements Ea, the pressure in the pressure chamber Ca fluctuates, causing ink to be ejected from the nozzle Nz.

[0082] Let's return to the explanation in Figure 8. A protective section 46 is placed on the diaphragm 44. A flexible substrate 51 is also 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 piezoelectric 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 for driving each piezoelectric element Ea, to each piezoelectric element Ea.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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 plates 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.

[0094] 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.

[0095] To detect signs of ink leakage from the liquid spray head 30 to the outside through the flow path, this disclosure uses a detection space FA and residual vibrations acquired for purposes such as identifying spraying abnormalities of the nozzle Nz to detect signs of ink leakage from the liquid spray head 30. Residual vibrations represent vibrations remaining in the pressure chamber C after the piezoelectric element E has been driven. The method for acquiring residual vibration information NEI, which indicates residual vibrations, will be described below using the electrical configuration and operation of the liquid spray head 30.

[0096] 1-8. Electrical configuration of the liquid injection head 30 The configuration of the liquid injection head 30 will be described below with reference to Figure 13.

[0097] Figure 13 is a block diagram showing an example of the electrical configuration of the liquid injection head 30. Figure 13 shows the head unit Hn provided on the liquid injection head 30.

[0098] The drive circuit 50 includes a switching circuit 52 and a detection circuit 55. The switching circuit 52, under the control of the control circuit 21, switches whether or not to supply a drive signal Com output from the drive signal generation circuit 114 to each of the multiple piezoelectric elements E of the head unit Hn. The switching circuit 52 also switches whether or not to electrically connect each piezoelectric element E to the detection circuit 55. In this embodiment, it is assumed that the drive signal Com includes drive signals Com-A and Com-B. Furthermore, the signal actually supplied to the piezoelectric element E from drive signals Com-A and Com-B may be described as the supplied drive signal Vin. The switching circuit 52 includes, for example, a group of switches such as a transmission gate for the switching. The detection circuit 55 outputs a residual vibration signal NES, which indicates the vibration remaining in the pressure chamber C described later, to the generation circuit 29 after the piezoelectric element E has been driven. More specifically, the detection circuit 55 generates the residual vibration signal NES based on the detection signal Vout detected from the piezoelectric element E driven by the drive signal Com.

[0099] In addition to the head unit Hn, the liquid injection head 30 includes internal wiring LHa to which the drive signal Com-A is supplied from the drive signal generation circuit 114, internal wiring LHb to which the drive signal Com-B is supplied from the drive signal generation circuit 114, internal wiring LHs for supplying the detection signal Vout detected from the piezoelectric element E to the detection circuit 55, and internal wiring LHd to which the offset potential VBS is supplied.

[0100] As shown in Figure 13, the switching circuit 52 comprises 2N switches SWa[a1] to SWa[bN], 2N switches SWb[a1] to SWb[bN], 2N switches SWs[a1] to SWs[bN], and a connection state specification circuit 53 that specifies the connection state of each switch. For example, transmission gates can be used as each switch. The connection status specification circuit 53 generates connection status specification signals SLa[a1]~SLa[bN] that specify the on / off state of switches SWa[a1]~SWa[bN], connection status specification signals SLb[a1]~SLb[bN] that specify the on / off state of switches SWb[a1]~SWb[bN], and connection status specification signals SLs[a1]~SLs[bN] that specify the on / off state of switches SWs[a1]~SWs[bN], based on at least some of the print signal SI, latch signal LAT, and period specification signal Tsig supplied from the control circuit 21.

[0101] Switch SWa[p1n1] switches between conduction and non-conductivity between the internal wiring LHa and the lower electrode [p1n1] of the piezoelectric element E[p1n1], according to the connection status signal SLa[p1n1]. For example, switch SWa[p1n1] turns on when the connection status signal SLa[p1n1] is high level and turns off when it is low level. Switch SWb[p1n1] switches between conduction and non-conductivity between the internal wiring LHb and the lower electrode [p1n1] of the piezoelectric element E[p1n1], according to the connection status specification signal SLb[p1n1]. For example, switch SWb[p1n1] turns on when the connection status specification signal SLb[p1n1] is high level and turns off when it is low level. The switch SWs[p1n1] switches between conduction and non-conductivity between the internal wiring LHs and the lower electrode [p1n1] of the piezoelectric element E[p1n1], according to the connection status specification signal SLs[p1n1]. For example, the switch SWs[p1n1] turns on when the connection status specification signal SLs[p1n1] is high level and turns off when it is low level.

[0102] The detection circuit 55 receives the detection signal Vout[p1n1] output from the piezoelectric element E[p1n1] via internal wiring LHs. The detection circuit 55 then generates a residual vibration signal NES based on the detection signal Vout[p1n1]. The residual vibration signal NES is an analog signal.

[0103] The detection circuit 55 may include, for example, a negative feedback amplifier for amplifying the detection signal Vout, a low-pass filter for attenuating the high-frequency components of the detection signal Vout, and a voltage follower that converts impedance to output a low-impedance residual vibration signal NES.

[0104] The generation circuit 29 generates residual vibration information NEI based on the residual vibration signal NES. The residual vibration information NEI is a digital signal. For example, the generation circuit 29 samples the residual vibration signal NES at regular intervals and generates residual vibration information NEI by associating time information, which indicates the time of sampling with respect to an arbitrary starting point, with a value indicating the potential obtained from the sampling.

[0105] 1-9. Operation of the liquid spray head 30 The operation of the liquid spray head 30 will be described below with reference to Figure 14. In this embodiment, the operating period of the inkjet printer 100 includes one or more recording periods Tu. In this embodiment, the inkjet printer 100 is assumed to perform either driving each piezoelectric element E in the printing process or driving each piezoelectric element E for acquiring residual vibration information NEI during each recording period Tu. However, this disclosure is not limited to this embodiment, and it may be possible to perform both driving each piezoelectric element E in the printing process and driving each piezoelectric element E for acquiring residual vibration information NEI during each recording period Tu. Hereinafter, the process of acquiring residual vibration information NEI may be referred to as the residual vibration acquisition process. Generally, an inkjet printer 100 forms an image based on image data Img by ejecting ink from each nozzle Nz one or more times over multiple continuous or intermittent recording periods Tu.

[0106] Figure 14 is a timing chart illustrating the operation of the inkjet printer 100 during the recording period Tu. As shown in Figure 14, the control circuit 21 outputs a latch signal LAT having a pulse PlsL. The control circuit 21 then defines the recording period Tu as the period from the rising edge of pulse PlsL to the rising edge of the next pulse PlsL.

[0107] The printing signal SI includes individual designation signals Sd[a1] to Sd[bN] that specify the mode of driving the piezoelectric elements E[a1] to E[bN] during each recording period Tu. When at least one of the printing process and the residual vibration acquisition process is performed during the recording period Tu, the control circuit 21 supplies the printing signal SI, including the individual designation signals Sd[a1] to Sd[bN], to the connection state designation circuit 53 in synchronization with the clock signal CL prior to the start of the recording period Tu, as shown in Figure 14. In this case, the connection state designation circuit 53 generates connection state designation signals SLa[p1n1], SLb[p1n1], and SLs[p1n1] during the recording period Tu, based on the individual designation signal Sd[p1n1].

[0108] In this embodiment, the individual designation signal Sd[p1n1] is a signal that, for each recording period Tu, specifies one of three drive modes for the piezoelectric element E[p1n1]: ink ejection, non-ejection of ink, and drive as the target of operation for residual vibration acquisition processing.

[0109] As shown in Figure 14, the drive signal generation circuit 114 outputs a drive signal Com-A having an injection waveform PX. The injection waveform PX has a minimum potential VLX and a maximum potential VHX. The potential of the injection waveform PX at the start and end is set to the reference potential V0.

[0110] Then, when the individual designation signal Sd[n1] specifies ink ejection to the piezoelectric element E[n1], the connection state designation circuit 53 sets the connection state designation signal SLa[n1] to a high level during the recording period Tu, and sets the connection state designation signals SLb[n1] and SLs[n1] to low levels during the recording period Tu. In this case, the nozzle Nz[n1] ejects ink during the recording period Tu, and dots are formed on the medium PP.

[0111] As shown in Figure 14, the drive signal generation circuit 114 outputs a drive signal Com-B having a test waveform PS provided during the recording period Tu. In this embodiment, the test waveform PS is determined such that the potential difference between the highest potential VHS and the lowest potential VLS of the test waveform PS is smaller than the potential difference between the highest potential VHX and the lowest potential VLX of the injection waveform PX. Specifically, when supplying the drive signal Com-B having the test waveform PS to the piezoelectric element E[n1], the test waveform PS is determined such that the piezoelectric element E[n1] is driven to the extent that ink is not ejected from the nozzle Nz[n1]. The start and end potentials of the test waveform PS are set to the reference potential V0.

[0112] Furthermore, the control circuit 21 outputs a period specification signal Tsig having pulses PlsT1 and PlsT2. As a result, the control circuit 21 divides the recording period Tu into three control periods: TSS1, from the start of pulse PlsL to the start of pulse PlsT1; TSS2, from the start of pulse PlsT1 to the start of pulse PlsT2; and TSS3, from the start of pulse PlsT2 to the start of the next pulse PlsL.

[0113] Then, when the individual designation signal Sd[n1] designates the nozzle Nz[n1] as the target for operation as a residual vibration acquisition process, the connection state designation circuit 53 sets the connection state designation signal SLa[n1] to a low level during the recording period Tu, sets the connection state designation signal SLb[n1] to a high level during the control periods TSS1 and TSS3 and to a low level during the control period TSS2, and sets the connection state designation signal SLs[n1] to a low level during the control periods TSS1 and TSS3 and to a high level during the control period TSS2. In this case, the piezoelectric element E[n1] is driven by the drive signal Com-B of the test waveform PS during the control period TSS1. As a result, vibration occurs in the pressure chamber C[n1], and this vibration persists during the control period TSS2. During the control period TSS2, the lower electrode of the piezoelectric element E[n1] changes its potential in accordance with the residual vibration occurring in the pressure chamber C[n1]. In other words, during the control period TSS2, the lower electrode of the piezoelectric element E[n1] exhibits a potential corresponding to the electromotive force of the piezoelectric element E[n1] caused by the residual vibration occurring in the pressure chamber C[n1]. The potential of this lower electrode can then be detected as a detection signal Vout during the control period TSS2.

[0114] 1-10. About the detection space FA The control circuit 21 can identify spraying abnormalities in the liquid spray head 30 by analyzing the residual vibration information NEI. For example, if the spraying state of nozzle Nz is abnormal due to air bubbles being mixed into nozzle Nz, the frequency of residual vibration will be higher compared to when there are no air bubbles in nozzle Nz. Also, generally, if the spraying state of nozzle Nz is abnormal due to foreign matter such as paper dust adhering near nozzle Nz, the frequency of residual vibration will be lower compared to when there is no foreign matter adhering. Therefore, the inkjet printer 100 can select an appropriate cleaning process by analyzing the type of spraying abnormality using residual vibration information NEI.

[0115] The inventors discovered that the characteristics of residual vibration differ depending on whether or not ink is present in the pressure chamber C. Specifically, the inventors found that when there is no ink in the pressure chamber C, the period until the residual vibration decays is shorter and the amplitude of the second and subsequent peaks of the residual vibration is smaller compared to when there is ink in the pressure chamber C. Therefore, in this embodiment, a mechanism for acquiring residual vibration information NEI is used to use at least a part of one or more individual flow paths RJ out of 2N individual flow paths RJ as a detection space FA, and the detection space FA is separated from the flow path SF by a fragile adhesive part GLW that is intentionally more fragile than the adhesive part GL. If ink leaks from the fragile adhesive part GLW and ink is present in the detection space FA, the control circuit 21 can detect that ink has leaked from the fragile adhesive part GLW using the residual vibration information NEI. That is, the detection space FA is not part of the flow path SF in the initial state of the liquid spray head 30, but becomes part of the flow path SF after ink leaks from the fragile adhesive part GLW. In this specification, the initial state of the liquid spray head 30 refers to the state after the liquid spray head 30 has been manufactured but before it has been filled with ink. Alternatively, the initial state of the liquid spray head 30 can also be described as the state in which the adhesive portion GL has never come into contact with ink. If ink leaks from the fragile adhesive portion GLW, it can be estimated that the adhesive portion GL has deteriorated and that ink may soon leak from the adhesive portion GL by analyzing the residual vibration information NEI obtained from the piezoelectric element E that applies pressure to the pressure chamber C of the individual flow path RJ used as the detection space FA.

[0116] For the sake of simplicity, in the first embodiment, unless otherwise specified, it is assumed that all of the individual channel RJs are used as the detection space FA. Any of the 2N individual channel RJs may be used as the detection space FA, but it is preferable that the individual channel RJs located at the end in the Y1 direction or at the end in the Y2 direction are used. Furthermore, of the 2N individual channel RJs, either the individual channel RJ communicating with the nozzle Nz divided into the first nozzle row La and the individual channel RJ communicating with the nozzle Nz divided into the second nozzle row Lb may be used as the detection space FA, or both may be used as the detection space FA. In the following, for the sake of simplicity, an example in which individual channel RJ[aN] is used as the detection space FA will be used.

[0117] Figure 15 is a diagram illustrating the detection space FA in the first embodiment. In Figure 15, the individual channel RJ[aN] used as the detection space FA is shown in an enlarged view. Hereafter, for the sake of simplicity, the individual channel RJ used as the detection space FA may be referred to as the dummy individual channel RJD. Similarly, the pressure chamber C included in the dummy individual channel RJD may be referred to as the dummy pressure chamber CD, the piezoelectric element E that applies pressure inside the dummy pressure chamber CD may be referred to as the dummy piezoelectric element ED, and the nozzle Nz communicating with the dummy individual channel RJD may be referred to as the dummy nozzle NzD. In the example of Figure 15, the pressure chamber Ca[aN] is the dummy pressure chamber CD, the piezoelectric element Ea[aN] is the dummy piezoelectric element ED, and the nozzle Nz[aN] is the dummy nozzle NzD.

[0118] The dummy individual channel RJD, dummy piezoelectric element ED, and dummy nozzle NzD, used as the detection space FA, do not directly contribute to forming an image on the medium PP. Not directly contributing to image formation means they are not used to spray ink onto the medium PP to form dots that constitute part of an image. The dummy individual channel RJD is not a sealed space because it is in communication with the dummy nozzle NzD.

[0119] The dummy individual channel RJD is partitioned from the first liquid storage chamber Ra by a fragile adhesive section GLW. The fragile adhesive section GLW is provided so as to block the opening 37Ka, i.e., at the Z2 end of the second communication channel R4a.

[0120] Preferably, the fragile adhesive portion GLW is provided in such a way that it is intentionally more prone to deterioration than the most easily deteriorated adhesive portion GL among the multiple adhesive portions GL in the liquid spray head 30. The most easily deteriorated adhesive portion GL among the multiple adhesive portions GL in the liquid spray head 30 is the adhesive portion GL that has the shortest distance from the position defining the flow path SF in the initial state of the liquid spray head 30 to the position opposite to the end of the adhesive portion GL that defines the flow path SF, assuming that the ink conditions in contact with the multiple adhesive portions GL in the liquid spray head 30 are the same. Hereinafter, the shortest distance from the part of the adhesive portion GL or fragile adhesive portion GLW that defines the flow path SF to the part opposite to the end of the flow path SF in the initial state of the liquid spray head 30 may be referred to as the "ink penetration distance". In this embodiment, the explanation will proceed assuming that the most easily deteriorated adhesive portion GL is adhesive portion GL57. However, if the condition of the ink in contact with multiple adhesive parts GL within the liquid spray head 30 differs from that of the other, the adhesive part GL that is most susceptible to deterioration may be the adhesive part GL located in a high-flow area within the flow path SF, or it may be the adhesive part GL located in a high-temperature area within the flow path SF. High-temperature areas within the flow path SF include the vicinity of the piezoelectric element E, and the vicinity of a heater (not shown) that is provided when an ink that needs to be used at high temperatures, such as UV ink, is used.

[0121] In the first embodiment, the adhesive portion GL57 is an example of the "first adhesive portion," the flow path plate Su5 is an example of the "first flow path member," and the case 335 is an example of the "second flow path member." The fragile adhesive portion GLW is an example of the "second adhesive portion." However, the set of the "first flow path member" and the "second flow path member" is not limited to the set of the flow path plate Su5 and the case 335, but may be any two members that constitute the liquid injection head 30, which form part of the flow path SF and are bonded together with some kind of adhesive. Specifically, the set of two flow path members may be a set of two adjacent flow path plates Su within the flow path structure 33, and a set 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.

[0122] There are two embodiments of intentionally making the fragile adhesive portion GLW more prone to deterioration than the adhesive portion GL57, as shown below. In the first embodiment of the fragile adhesive portion GLW, the adhesive forming the fragile adhesive portion GLW and the adhesive forming the adhesive portion GL57 are of the same type, and the ink penetration distance LGW of the fragile adhesive portion GLW is shorter than the ink penetration distance L57 of the adhesive portion GL57, as shown in Figure 7. The ink penetration distance LGW is the length of the fragile adhesive portion GLW in the direction along the Z axis in the initial state of the liquid spray head 30. In other words, the ink penetration distance LGW is the shortest distance from the end face in the Z2 direction where the fragile adhesive portion GLW defines the first liquid storage chamber Ra to the end face in the Z1 direction where the fragile adhesive portion GLW defines the detection space FA. The ink penetration distance L57 is the length of the adhesive portion GL57 in the direction along the X axis in the initial state of the liquid spray head 30. In other words, the ink penetration distance L57 is the shortest distance from the end face in the X1 direction that defines the first liquid storage chamber Ra of the adhesive portion GL57 to the end face opposite to the end face in the X1 direction that defines the first liquid storage chamber Ra.

[0123] In a second embodiment of the fragile adhesive section GLW, the liquid resistance of the fragile adhesive section GLW is lower than that of the adhesive section GL57. However, it is preferable that the liquid resistance of the fragile adhesive section GLW is slightly lower than that of the adhesive section GL57. For example, by changing the ratio of the main component to the hardener in the fragile adhesive section GLW compared to the ratio of the main component to the hardener in the adhesive section GL57, it is possible to create a fragile adhesive section GLW with slightly reduced liquid resistance. Alternatively, at the time of manufacturing the liquid spray head 30, it is possible to apply heat locally to the fragile adhesive section GLW using a laser or the like to partially advance the curing reaction, thereby lowering the final degree of curing of the fragile adhesive section GLW.

[0124] The fragile adhesive portion GLW may be provided in locations other than the opening 37Ka. For example, it may be provided at the Z1 end of the second communication channel R4a, or it may be provided in the middle of the second communication channel R4a. The configuration in which the fragile adhesive portion GLW is provided at the Z1 end of the second communication channel R4a, and the configuration in which it is provided in the middle of the second communication channel R4a, are examples of configurations in which a part of the individual channel RJ is used as the detection space FA. In the configuration in which a part of the individual channel RJ is used as the detection space FA, air bubbles may accumulate in the channels of the individual channel RJ that are not used as the detection space FA, and there is a risk that the contact of ink with the fragile adhesive portion GLW may be hindered by the air bubbles. As a result, in the configuration in which the entire individual channel RJ is used as the detection space FA, the liquid contact period of the fragile adhesive portion GLW becomes closer to the liquid contact period of the adhesive portion GL57, compared to the configuration in which a part of the individual channel RJ is used as the detection space FA, and the accuracy of estimating the deterioration of the adhesive portion GL57 can be improved.

[0125] Furthermore, in the example shown in Figure 15, the dummy nozzle NzD is in communication with the dummy individual channel RJD, but the dummy nozzle NzD does not necessarily have to be provided. However, by providing the dummy nozzle NzD, if ink enters the dummy individual channel RJD, the air and ink in the dummy individual channel RJD are rapidly replaced via the dummy nozzle NzD. Therefore, the configuration in which the dummy nozzle NzD is in communication with the dummy individual channel RJD allows for the rapid detection of signs of ink leakage from the liquid spray head 30 when ink enters from the fragile adhesive portion GLW, compared to the configuration without the dummy nozzle NzD.

[0126] 1-11. Function of the First Embodiment The residual vibration information NEI obtained from the dummy piezoelectric element ED allows for the estimation of the deterioration state of the adhesive portion GL57. Furthermore, it is preferable to replace the liquid ejection head 30 before ink leaks from it. Therefore, the inkjet system SYS provides a function that prompts the user U to replace the liquid ejection head 30 if it is estimated that the adhesive portion GL57 is in a deteriorated state.

[0127] Figure 16 is a diagram showing the functions of the inkjet system SYS. Figure 17 is a flowchart showing the operation of the inkjet system SYS. The control circuit 21 functions as an acquisition unit 71, an estimation unit 73, and a notification unit 75 by executing the read control program PM2.

[0128] The series of processes shown in Figure 17 are performed periodically. For example, the inkjet system SYS performs the series of processes shown in Figure 17 daily, weekly, or monthly. However, the series of processes shown in Figure 17 may be performed irregularly. For example, when the inkjet system SYS receives image data Img from the processing unit 200, it may perform the series of processes shown in Figure 17 before the printing process, or it may perform the series of processes shown in Figure 17 at the instruction of user U.

[0129] Even if the fragile adhesive section GLW is not deteriorated, ink may be forced from the dummy nozzle NzD into the dummy individual channel RJD, and the wiping process performed before and after the printing process may cause the air in the dummy individual channel RJD to be replaced with ink. To discharge the ink from the dummy individual channel RJD while the fragile adhesive section GLW is not deteriorated, it is preferable to perform a cleaning process before executing the series of processes shown in Figure 17.

[0130] In step SC2, the control circuit 21 performs residual vibration acquisition processing. Specifically, the control circuit 21 outputs a waveform specification signal dCom to the drive signal generation circuit 114 to generate a drive signal Com-B including the inspection waveform PS, and transmits a print signal SI to the liquid spray head 30, which includes an individual specification signal Sd indicating that the drive signal Com-B should be supplied to the dummy piezoelectric element ED. After the processing of step SC2 is completed, the control circuit 21 waits for a response from the generation circuit 29.

[0131] In step SH2, the liquid spray head 30 supplies a drive signal Com-B, including a test waveform PS, to the dummy piezoelectric element ED, in accordance with the print signal SI from the control circuit 21. Then, in step SH4, the liquid spray head 30 outputs a residual vibration signal NES to the generation circuit 29. After the processing in step SH4 is completed, the liquid spray head 30 completes the series of processes shown in Figure 17.

[0132] When the generation circuit 29 receives the residual vibration signal NES from the liquid injection head 30, in step SR2, the generation circuit 29 generates residual vibration information NEI based on the residual vibration signal NES and transmits the residual vibration information NEI to the control circuit 21. After the processing of step SR2 is completed, the generation circuit 29 terminates the series of processes shown in Figure 17.

[0133] In step SC4, the control circuit 21 functions as an acquisition unit 71 to acquire residual vibration information NEI from the generation circuit 29. The acquired residual vibration information NEI can be said to be information regarding the presence or absence of ink in the dummy individual channel RJD, which is the detection space FA.

[0134] Next, in step SC6, the control circuit 21 functions as an estimation unit 73 to estimate the degree of deterioration of the adhesive portion GL57 based on the residual vibration information NEI. Specifically, in order to estimate the degree of deterioration of the adhesive portion GL57, the memory circuit 22 stores a period threshold indicating the period until the residual vibration attenuates when it can be assumed that ink is present in the dummy individual flow path RJD, and an amplitude threshold indicating the amplitude at the second peak of the residual vibration. The period until the residual vibration attenuates is, for example, the period from the start time of the residual vibration until the value of the amplitude at the second and subsequent peaks of the residual vibration falls below a predetermined value, such as one-tenth or less, compared to the amplitude at the first peak of the residual vibration. The control circuit 21 identifies the period until the residual vibration attenuates and the amplitude at the second peak of the residual vibration from the residual vibration information NEI. Furthermore, if the specified period is shorter than the period threshold and the specified amplitude is smaller than the amplitude threshold, the control circuit 21 estimates that the adhesive part GL57 is degraded because ink has leaked from the fragile adhesive part GLW and ink is present in the dummy individual channel RJD.

[0135] After the processing in step SC6 is completed, in step SC8, the control circuit 21 determines, based on the estimation result, whether or not the user U should be notified. More specifically, if the control circuit 21 estimates that the adhesive portion GL57 is degraded, it determines that the user U should be notified.

[0136] If the determination result in step SC8 is positive, the control circuit 21 functions as a notification unit 75 in step SC10 to generate notification information CI based on the estimation result and notifies the user U of the generated notification information CI. Specifically, the control circuit 21 transmits the notification information CI to the processing unit 200, causing the processing unit 200 to notify the user U of the notification information CI. The notification information CI is information that prompts the replacement of the liquid spray head 30 which shows signs of ink leakage. For example, let's assume that the estimation result is that the adhesive part GL57 of the liquid spray head 30 is deteriorated, that is, that there are signs of ink leakage from the liquid spray head 30. Under this premise, the notification information CI is a string of characters that reads, "There are signs that the liquid spray head is malfunctioning. There are signs that ink is leaking from this liquid spray head. Please replace the liquid spray head." However, the notification information CI is not limited to a string of characters. For example, the notification information CI may be information showing an image in which an enhanced image is superimposed on an image showing the head module 3, highlighting the liquid spray head 30 that shows signs of ink leakage. The enhanced image may be, for example, an image in which the color of the liquid spray head 30 showing signs of ink leakage is different from the color of the liquid spray head 30 that does not show signs of ink leakage, or an image with a callout pointing to the liquid spray head 30 showing signs of ink leakage, with the text "We recommend replacing this liquid spray head." inside the callout.

[0137] Furthermore, the estimation unit 73 may estimate the lifespan of the liquid spray head 30 based on the degree of deterioration of the adhesive portion GL57 and the period from the date the liquid spray head 30 was put into use to the current date. For example, the memory circuit 22 stores information indicating the date the liquid spray head 30 was put into use, information indicating the first period from the date the liquid spray head 30 was put into use until ink leaks from the fragile adhesive portion GLW, obtained by the head manufacturer through experiments, etc., and information indicating the second period from the date the liquid spray head 30 was put into use until ink leaks from the adhesive portion GL57. The estimation unit 73 then assumes that ink leakage from the fragile adhesive portion GLW of the liquid spray head 30 has been detected. The estimation unit 73 calculates the lifespan of the liquid spray head 30 using the following formula (1). Lifespan of liquid spray head 30 = (Current date - Date when liquid spray head 30 was first used) × (Second period / First period) + Current date (1)

[0138] The notification unit 75 includes lifespan information, which is estimated by the estimation unit 73, in the notification information CI and notifies the user U. The lifespan information is, for example, a string of characters such as, "The expected date on which the liquid spray head 30 will fail is yyyy / mm / dd." where yyyy is a four-digit number, mm is an integer from 1 to 12, and dd is an integer from 1 to 31. The notification unit 75 may also notify the user U of the notification information CI when it detects that ink has leaked from the fragile adhesive part GLW, or it may notify the user of the notification information CI a predetermined number of days before the date indicated in the lifespan information.

[0139] After the processing in step SC10 is completed, the control circuit 21 terminates the series of processes shown in Figure 17. Also, if the determination result in step SC8 is negative, the control circuit 21 terminates the series of processes shown in Figure 17.

[0140] When the processing unit 200 receives notification information CI, the control circuit 210 of the processing unit 200 notifies the user U of the notification information CI in step SS2. Specifically, the control circuit 210 causes the display device 270 to display the string or image indicated by the notification information CI.

[0141] In Figures 16 and 17, the control circuit 21 functions as the estimation unit 73 and the notification unit 75, but this is not limited to this configuration. For example, the control circuit 21 may transmit residual vibration information NEI to the processing unit 200, and the control circuit 210 of the processing unit 200 may function as the estimation unit 73 and the notification unit 75.

[0142] 1-12. Summary of the First Embodiment In the following, the first embodiment is summarized as follows, with the "first flow channel member" being the flow channel plate Su5, the "second flow channel member" being the case 335, the "first adhesive part" being the adhesive part GL57, the "common liquid chamber" being the first liquid storage chamber Ra, and the "multiple individual flow channels" being N individual flow channels RJa.

[0143] The liquid spray head 30 in the first embodiment includes 2N nozzles Nz for spraying ink, a flow path plate Su5 that defines a part of the flow path SF communicating with the 2N nozzles Nz, a case 335 that defines a part of the flow path SF, an adhesive portion GL57 for liquid-tightly connecting a part of the flow path SF of the flow path plate Su5 and a part of the flow path SF of the case 335, and an adhesive portion GL that defines the inner wall of the flow path SF, and a fragile adhesive portion GLW that defines a detection space FA separated from the flow path SF, which is a space for detecting the degree of deterioration of the adhesive portion GL57. According to the first embodiment, the degree of deterioration of the adhesive portion GL57 can be estimated by detecting that the fragile adhesive portion GLW has deteriorated due to contact with liquid and that ink has entered the detection space FA. The user U can know the time when deterioration of the adhesive portion GL57 is detected as an appropriate time to replace the liquid spray head 30. Furthermore, according to the first embodiment, the degree of deterioration of the adhesive portion GL57 can be estimated with greater accuracy for various inks compared to the method of predicting the degree of deterioration of the adhesive portion GL57 by counting the liquid flow time.

[0144] Furthermore, in the first aspect of the fragile adhesive portion GLW, the adhesive forming the fragile adhesive portion GLW and the adhesive forming the adhesive portion GL57 are of the same type. Since the adhesive forming the fragile adhesive portion GLW and the adhesive forming the adhesive portion GL57 are of the same type, the degradation conditions of the fragile adhesive portion GLW and the adhesive portion GL57 can be made identical for various inks. As a result of being able to make the degradation conditions identical, according to the first embodiment, compared to the embodiment in which the adhesives are of different types, the rate of degradation of the fragile adhesive portion GLW and the adhesive portion GL57 when in contact with ink can be made more similar, and the accuracy of estimating the degree of degradation of the adhesive portion GL57 can be improved.

[0145] Furthermore, in the first embodiment of the fragile adhesive portion GLW, the ink penetration distance LGW, which is the shortest distance from the portion defining the flow path SF of the fragile adhesive portion GLW to the portion defining the detection space FA, is shorter than the ink penetration distance L57, which is the shortest distance from the portion defining the flow path SF to the end of the adhesive portion GL57 opposite to the portion defining the flow path SF. According to the first embodiment, compared to an embodiment in which the ink penetration distance LGW is longer than the ink penetration distance L57, it is possible to detect signs of ink leakage from the adhesive portion GL57 before the point in time when ink actually leaks from the adhesive portion GL57.

[0146] Furthermore, in a second embodiment of the weak adhesive portion GLW, the liquid resistance of the weak adhesive portion GLW is lower than that of the adhesive portion GL57. According to the first embodiment, signs of ink leakage from the adhesive portion GL57 can be detected before ink actually leaks from the adhesive portion GL57.

[0147] Furthermore, the flow path SF includes N individual flow paths RJa that communicate with each of the N nozzles Nz, and a first liquid storage chamber Ra that is commonly connected to the N individual flow paths RJa. The fragile adhesive section GLW partitions at least a portion of the dummy individual flow path RJD as a detection space FA relative to the first liquid storage chamber Ra. According to the first embodiment, since it is sufficient to use at least a portion of one or more individual channel RJ out of the N individual channel RJa as the detection space FA, the detection space FA can be formed simply by providing a fragile adhesive portion GLW.

[0148] Furthermore, the liquid injection head 30 forms an image by spraying ink onto the medium PP, and further comprises a dummy piezoelectric element ED that does not directly contribute to image formation, and the dummy individual flow path RJD includes a dummy pressure chamber CD into which pressure is applied by the dummy piezoelectric element ED. According to the first embodiment, since the mechanism for acquiring residual vibration information NEI, which is provided to perform an appropriate cleaning process, can detect signs of ink leakage from the adhesive portion GL57, there is no need to provide a new sensor to detect signs of ink leakage from the adhesive portion GL57.

[0149] The inkjet printer 100 also includes a liquid jet head 30 and a control circuit 21. The control circuit 21 functions as an acquisition unit 71 that acquires residual vibration information NEI, which is information regarding the presence or absence of ink in the detection space FA, and an estimation unit 73 that estimates the degree of deterioration of the adhesive part GL57 based on the residual vibration information NEI acquired by the acquisition unit 71. According to the first embodiment, the degree of deterioration of the adhesive portion GL57 can be estimated. Furthermore, according to this embodiment, signs of ink leakage from the liquid spray head 30 can be detected without damaging the liquid spray head 30.

[0150] Furthermore, the control circuit 21 also functions as a notification unit 75 that prompts the replacement of the liquid spray head 30 when the estimation unit 73 estimates that the adhesive portion GL57 is deteriorating. According to the first embodiment, user U can replace the liquid spray head 30 before ink leaks from it by replacing the liquid spray head 30 in accordance with the instruction to replace the liquid spray head 30.

[0151] 2. Second Embodiment In the first embodiment, a mechanism for acquiring residual vibration information NEI was used, and a dummy individual channel RJD was provided to estimate whether or not the adhesive portion GL was deteriorating. However, the embodiment is not limited to this, and a detection space FA for estimating whether or not the adhesive portion GL is deteriorating may be provided separately from the dummy individual channel RJD. The second embodiment will be described below.

[0152] Figure 18 is a block diagram showing an example configuration of the inkjet printer 100a in the second embodiment. The inkjet printer 100a has a liquid jet head 30a instead of a liquid jet head 30, a control circuit 21a instead of a control circuit 21, a memory circuit 22a instead of a memory circuit 22, and a measurement circuit 80 instead of a generation circuit 29. The liquid jet head 30a has a detection space FAa instead of a detection space FA. A detection mechanism 60 is provided near the detection space FAa. The detection space FAa will be explained using Figures 19 and 20.

[0153] 2-1. Detection space FAa in the second embodiment Figures 19 and 20 are diagrams illustrating the detection space FAa. Figures 19 and 20 show an example in which the liquid injection head 30 shown in Figure 12 is replaced with a liquid injection head 30a, and the detection space FAa is provided within the region RG1 shown in Figure 12. Region RG1 includes a supply channel Sh1 which is part of the internal supply channel S1b and is formed by channel plates Su4 and Su5. Furthermore, in the following figures, the channel structure 33 and the shape of the channel inside the channel structure 33 are shown in a simplified manner to avoid complexity in the drawings. Figure 19 shows an enlarged view of region RG1 of the liquid injection head 30a. Figure 20 shows a cross-section when the liquid injection head 30a is broken along the line aa shown in Figure 19.

[0154] As shown in Figure 19, the supply channel Sh1 has a vertical channel Sh11 extending along the Z axis, a horizontal channel Sh12 extending perpendicular to the Z axis, and a vertical channel Sh13 extending along the Z axis. In Figure 20, the position of the vertical channel Sh11 is shown to illustrate the positional relationship. The Z2 end of the vertical channel Sh11 communicates with the Y2 end of the horizontal channel Sh12. The Y1 end of the horizontal channel Sh12 communicates with the Z1 end of the vertical channel Sh13.

[0155] The liquid injection head 30a has a flow path plate Su5a instead of the flow path plate Su5. In the flow path plate Su5a, a recess RC1 is provided on the bottom surface SZ1 of the horizontal flow path Sh12. The opening of the recess RC1 opens in the Z1 direction. The Z1 direction is opposite to the direction in which the nozzle Nz opens. In the second embodiment, the detection space FAa is defined by closing the opening of the recess RC1 with the fragile adhesive portion GLWa in the second embodiment. In the second embodiment, in order to make the thickness of the fragile adhesive portion GLWa thin, a filter member Fc is provided so as to cover the opening of the recess RC1. The fragile adhesive portion GLWa is formed so as to cover the filter member Fc. In the initial state of the liquid injection head 30a, since the opening of the recess RC1 is covered by the fragile adhesive portion GLWa, the detection space FAa is a sealed space. Note that in Figure 20, the outline of the filter member Fc is shown with a dashed line to show the inside of the detection space FAa. Furthermore, in Figure 20, to avoid complicating the drawing, only the outline of the fragile adhesive portion GLWa is shown with a dashed line. The filter member Fc makes it possible to form a thin fragile adhesive portion GLWa. The filter member Fc is integrated with the flow path plate Su5a, for example, by insert molding. However, the filter member Fc does not necessarily have to be provided in the opening of the recess RC1.

[0156] As shown in Figure 18, a detection mechanism 60 is provided near the detection space FAa to determine whether or not ink is present in the detection space FA. The detection mechanism 60 includes a detection wire 61, a detection wire 62, an internal member wiring 63, an internal member wiring 64, and a detection conductor 65. Based on the magnitude of the current in the detection conductor 65, it is possible to detect signs of ink leakage from the adhesive portion GL57. In the second embodiment, it is assumed that the ink is conductive. A conductive ink is, for example, a water-based ink containing an electrolyte. However, the conductive ink is not limited to a water-based ink containing an electrolyte, but may also be a UV ink containing an electrolyte.

[0157] The detection wire 65 is positioned on the bottom surface of the detection space FAa. The detection wire 65 is U-shaped. The internal wiring 63 and internal wiring 64 penetrate the flow path plate Su5a in a direction along the X axis from the wall surface defining the X2 direction of the detection space FAa. The X1 end of the internal wiring 63 is connected to one end of the detection wire 65. The X1 end of the internal wiring 64 is connected to the other end of the detection wire 65. The X2 end of the internal wiring 63 is connected to the detection wiring 61. The X2 end of the internal wiring 64 is connected to the detection wiring 62. The detection wiring 61 and detection wiring 62 are connected to the circuit board 383u or 383v along the side wall of the flow path structure 33. The detection wiring 61 and detection wiring 62 are connected to the measurement circuit 80 via the circuit board 383u or 383v. The detection wire 65 is an example of a "wire for detecting the degree of deterioration of the first adhesive part provided in the detection space."

[0158] A method for detecting whether or not ink is present in the detection space FAa using the detection mechanism 60 will be described. The measurement circuit 80 determines whether or not ink is present in the detection space FAa based on the magnitude of the current between detection wires 61 and 62. Compared to the initial state of the liquid spray head 30a, where no ink is present in the detection space FAa, when the fragile adhesive part GLWa deteriorates and ink is present in the detection space FAa, a part of the detection conductor 65 is short-circuited by the ink, and the resistance between detection wires 61 and 62 decreases. Therefore, the current value between detection wires 61 and 62 when ink is present in the detection space FAa becomes larger than the current value between detection wires 61 and 62 when no ink is present in the detection space FAa. Therefore, as a measurement process, the measurement circuit 80 measures the current value between detection wires 61 and 62. The measurement circuit 80 then generates measurement information JI indicating the measured current value and transmits the measurement information JI to the control circuit 21a. The measurement information JI indicating the current value between detection wires 61 and 62 can be said to be information regarding the presence or absence of ink in the detection space FAa.

[0159] 2-2. Operation of the second embodiment Figure 21 is a flowchart showing the operation of the inkjet system SYS in the second embodiment. The control circuit 21a functions as an acquisition unit 71a, an estimation unit 73a, and a notification unit 75 by executing the control program PM2a read from the memory circuit 22a. Only the differences from Figure 17 will be explained below.

[0160] In step SC2a, the control circuit 21a transmits the request signal RI to the measurement circuit 80. After the processing of step SC2a is completed, the control circuit 21a waits for a response from the measurement circuit 80.

[0161] When the measurement circuit 80 receives the request signal RI, the measurement circuit 80 performs the measurement process in step SM2. After the processing in step SM2 is completed, the measurement circuit 80 transmits measurement information JI, which indicates the measurement result, to the control circuit 21 in step SM4. After the processing in step SM4 is completed, the measurement circuit 80 terminates the series of processes shown in Figure 21.

[0162] In step SC4a, the control circuit 21a functions as an acquisition unit 71a to acquire measurement information JI from the measurement circuit 80. Next, in step SC6a, the control circuit 21a functions as an estimation unit 73a to estimate the degree of deterioration of the adhesive part GL57 based on the measurement information JI. Specifically, in order to estimate the degree of deterioration of the adhesive part GL57, the memory circuit 22 stores a threshold value for the current value when it can be considered that ink is present in the detection space FAa. Then, if the current value between the detection wiring 61 and 62 is greater than the threshold value, the control circuit 21a estimates that ink is present in the detection space FAa and therefore the adhesive part GL57 is deteriorated.

[0163] 2-3. Summary of the Second Embodiment As described above, according to the second embodiment, the ink flowing through the supply channel Sh1 is conductive, and a detection wire 65 for detecting the degree of deterioration of the adhesive portion GL57 is arranged in the detection space FAa. According to the second embodiment, the degree of deterioration of the adhesive portion GL57 can be estimated by utilizing the fact that the electrical resistance of the detection wire 65 changes when the ink comes into contact with the detection wire 65.

[0164] Furthermore, the detection space FAa in the second embodiment is a sealed space. In the first embodiment, if the detection space FA is not a sealed space, and the fragile adhesive portion GLW deteriorates and ink is present in the detection space FA, there is a risk that ink may leak out of the liquid spray head 30 from the detection space FA before the ink leaks out of the adhesive portion GL. Therefore, according to the second embodiment, even if the fragile adhesive portion GLW deteriorates and ink is present in the detection space FAa, it is possible to suppress the leakage of ink from the detection space FAa to the liquid spray head 30a.

[0165] Furthermore, the detection space FAa is defined by closing the opening of the recess RC1, which is provided on the bottom surface SZ1 that defines the supply channel Sh1, with the fragile adhesive portion GLWa, and the opening of the recess RC1 opens in the opposite direction to the direction in which the nozzle Nz opens. In the embodiment where the detection space FAa is provided on the surface facing the bottom surface SZ1, there is a risk that the air present in the detection space FAa in the initial state of the liquid spray head 30 will not be discharged into the supply channel Sh1, and the ink will not come into contact with the detection wire 65. On the other hand, in the second embodiment, since the fragile adhesive portion GLWa is provided so as to block the recess RC1 formed in the bottom surface SZ1, if the fragile adhesive portion GLWa breaks, the air present in the detection space FAa will be more easily discharged by buoyancy, and the ink will be more easily brought into contact with the detection wire 65. This makes it possible to suppress false detections in which ink is present in the detection space FAa but is not detected as being present.

[0166] However, the detection space FAa was formed by closing the opening of a recess RC1 provided on the bottom surface SZ1 with a fragile adhesive portion GLWa, but is not limited to this. For example, the detection space FAa may be formed by providing a recess on the side or top surface defining the supply channel Sh1, and closing the opening of this recess with a fragile adhesive portion GLWa.

[0167] Furthermore, in the second embodiment, the control circuit 21a functions as an acquisition unit 71a that acquires measurement information JI, which is information regarding the presence or absence of ink in the detection space FAa, and an estimation unit 73a that estimates the degree of deterioration of the adhesive part GL57 based on the measurement information JI acquired by the acquisition unit 71a. In addition, the control circuit 21a may also function as a notification unit 75. According to the second embodiment, the user U can be notified of signs of ink leakage from the liquid spray head 30a by utilizing the fact that the resistance of the detection wire 65 changes when ink comes into contact with the detection wire 65.

[0168] 3. Third Embodiment In the third embodiment, the ink within the detection space FA is configured to be directly visible. The third embodiment will be described below.

[0169] 3-1. Configuration and Operation of the Third Embodiment Figure 22 is a block diagram showing an example configuration of the inkjet printer 100b in the third embodiment. The inkjet printer 100b has a liquid jet head 30b instead of a liquid jet head 30, a control circuit 21b instead of a control circuit 21, a storage circuit 22b instead of a storage circuit 22, and an imaging device 90 instead of a generation circuit 29. The liquid jet head 30b is provided with a detection space FAb instead of a detection space FA. The detection space FAb will be explained with reference to Figure 23.

[0170] Figure 23 is a diagram illustrating the detection space FAb. In Figure 23, the liquid injection head 30a shown in Figure 19 is replaced with a liquid injection head 30b, and a cross-section is shown when the liquid injection head 30b is fractured along the line bb shown in Figure 19.

[0171] The liquid injection head 30b has a flow path plate Su4b instead of the flow path plate Su4. As shown in Figure 23, the detection space FAb is defined by the flow path plates Su4b and Su5. The detection space FAb is defined by closing the opening of the recess RCX2, which is provided on the side surface SX2 in the X2 direction of the horizontal flow path Sh12, with the fragile adhesive portion GLWb in the third embodiment. As in the second embodiment, a filter member may be provided to cover the opening of the recess RCX2, and the fragile adhesive portion GLWb may be formed to cover this filter member.

[0172] The X2 end of the flow channel plate Su4b is formed by a light-transmitting member TR. In this specification, "light-transmitting" means a member with a thickness of 10 mm or less and a visible light transmittance of 50% or more. However, a high transmittance is preferable; specifically, a member with a thickness of 10 mm or less with a visible light transmittance of 70% or more is preferable, and 90% or more is even preferable. The light-transmitting member is formed from glass, and transparent resin materials such as transparent epoxy resin and transparent acrylic resin. As for the manufacturing method of the flow channel plate Su4b, for example, the light-transmitting member TR and a non-light-transmitting resin may be integrated by insert molding, or the light-transmitting member TR may be bonded to the non-light-transmitting resin with some adhesive. As shown in Figure 23, the X2 direction of the detection space FAb is defined by the light-transmitting member TR. The light-transmitting member TR is an example of a "member that defines a part of the detection space".

[0173] In the initial state of the liquid spray head 30b, as shown in Figure 23, the fragile adhesive portion GLWb closes the opening of the recess RCX2. Therefore, in the initial state of the liquid spray head 30b, the detection space FAb is filled with air and no ink is present. Thus, in the initial state of the liquid spray head 30b, the detection space FAb is a sealed space. When the fragile adhesive portion GLWb deteriorates, ink enters the detection space FAb. Therefore, by observing the detection mechanism 60Ab through the light-transmitting member TR and confirming whether or not ink is present in the detection space FAb, the degree of deterioration of the adhesive portion GL57 can be estimated.

[0174] Furthermore, if the fragile adhesive portion GLWb deteriorates and ink enters the detection space FAb, there is a risk that the air present in the detection space FAb will form bubbles and enter the horizontal channel Sh12. However, by performing a pumping process, which is a type of cleaning process, the bubbles that have entered the horizontal channel Sh12 can be removed.

[0175] The explanation returns to Figure 22. The imaging device 90 images the detection space FAb. The imaging device 90 has an imaging optical system and an image sensor. The imaging optical system is an optical system that includes at least one imaging lens and may include various optical elements such as prisms, or it may include zoom lenses, focus lenses, etc. From the viewpoint of making it easy to image the detection surface with the image sensor, the imaging optical system is preferably configured to include a wide-angle lens or a fisheye lens. The image sensor is composed of, for example, a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary MOS) image sensor. The image sensor takes an image via the imaging optical system and transmits image information GI indicating the captured image to the control circuit 21b.

[0176] In order for the imaging device 90 to image the detection space FAb, a through hole or transparent member is provided in the portion of the side wall of the cover member 31 in the X2 direction that overlaps with the detection space FAb when viewed along the X axis, so that the detection space FAb is visible from outside the liquid spray head 30b. Furthermore, the imaging device 90 may have a light source that illuminates the detection space FAb in order to make the image of the detection space FAb clearer.

[0177] The memory circuit 22b stores the control program PM2b in place of the control program PM2. As shown in Figure 22, the control circuit 21b functions as an acquisition unit 71b, an estimation unit 73b, and a notification unit 75 by executing the read control program PM2b.

[0178] 3-2. Operation of the Third Embodiment Figure 24 is a flowchart showing the operation of the inkjet system SYS in the third embodiment. Only the differences from the flowchart shown in Figure 21 are described below.

[0179] In step SC2b, the control circuit 21b transmits the request signal RI to the imaging device 90. After the processing in step SC2b is completed, the control circuit 21b waits for a response from the imaging device 90.

[0180] When the imaging device 90 receives the request signal RI, in step SK2, the imaging device 90 images the detection space FAb. Then, in step SK4, the imaging device 90 transmits image information GI, which shows the image of the detection space FAb, to the control circuit 21b. After the processing in step SK4 is completed, the imaging device 90 terminates the series of processes shown in Figure 24.

[0181] In step SC4b, the control circuit 21b functions as an acquisition unit 71b to acquire image information GI from the imaging device 90. Next, in step SC6b, the control circuit 21b functions as an estimation unit 73b to estimate the degree of deterioration of the adhesive part GL57 based on the image information GI. Specifically, the memory circuit 22b stores pre-deterioration image information, which shows an image of the detection space FAb taken when no ink is present in the detection space FAb, and post-deterioration image information, which shows an image of the detection space FAb taken when ink is present in the detection space FAb. The estimation unit 73b determines whether the image taken of the detection space FAb is closer to the image shown by the pre-deterioration image information or the image shown by the post-deterioration image information. If the image shown by the image information GI is determined to be closer to the image shown by the pre-deterioration image information, the estimation unit 73b estimates that the adhesive part GL57 has not deteriorated. On the other hand, if the image information GI determines that the image is similar to the image information after degradation, the estimation unit 73b estimates that the adhesive part GL57 is degraded. The pre-degradation image information and the post-degradation image information are stored in the memory circuit 22b in advance by the head manufacturer based on experiments.

[0182] In the third embodiment, the image information GI can be said to be information regarding the presence or absence of ink in the detection space FAb.

[0183] 3-3. Summary of the Third Embodiment As described above, according to the third embodiment, the light-transmitting member TR, which is a member that defines a part of the detection space FAb, is light-transmitting. According to the third embodiment, by making the detection space FAb visible from the outside, if ink leaks from the fragile adhesive part GLWb, the ink in the detection space FAb can be visually inspected, and the degree of deterioration of the adhesive part GL57 can be estimated.

[0184] Furthermore, in the third embodiment, the control circuit 21b functions as an acquisition unit 71b that acquires image information GI, which is information regarding the presence or absence of ink in the detection space FAb, and an estimation unit 73b that estimates the degree of deterioration of the adhesive part GL57 based on the image information GI acquired by the acquisition unit 71b. In addition, the control circuit 21b may also function as a notification unit 75. According to the second embodiment, by utilizing the fact that ink becomes present in the detection space FAb when ink leaks from the fragile adhesive portion GLWb, the user U can also be notified that there are signs of ink leakage from the liquid spray head 30b.

[0185] In the second embodiment, the inkjet printer 100b does not need to have an imaging device 90. The user U can detect signs of ink leakage from the liquid ejection head 30b by directly visually inspecting the detection space FAb of the liquid ejection head 30b. The liquid ejection head 30b may also have both a detection space FAb for visual inspection by the user U and a detection space FAb for imaging by the imaging device 90.

[0186] 4. Fourth Embodiment In the fourth embodiment, when ink enters the detection space FA, the pressure loss in the flow path SF changes, and by focusing on this, it is estimated whether or not the adhesive portion GL has deteriorated. The fourth embodiment will be described below.

[0187] 4-1. Configuration and Operation of the Fourth Embodiment Figure 25 is a block diagram showing an example configuration of the inkjet printer 100c in the fourth embodiment. The inkjet printer 100c has a liquid jet head 30c instead of a liquid jet head 30, a control circuit 21c instead of a control circuit 21, a memory circuit 22c instead of a memory circuit 22, and a flow meter 95 instead of a generation circuit 29. The liquid jet head 30c is provided with a detection space FAc instead of a detection space FA. The detection space FAc will be explained using Figure 26.

[0188] 4-2. Detection space FAc in the fourth embodiment Figure 26 is a diagram illustrating the detection space FAc. Figure 26 shows a cross-section of the supply section Pb1 within region RG2 shown in Figure 10 inside the liquid injection head 30c when it is fractured by a plane parallel to the XY plane.

[0189] The liquid injection head 30c has a flow path plate Su2c instead of a flow path plate Su2. As can be seen from Figures 10 and 26, the flow path plates Su1 and Su2c define the detection space FAc. The detection space FAc is a bypass flow path that branches off from the first connection CN1 of the supply unit Pb1 and rejoins the supply unit Pb1 at a second connection CN2 which is different from the first connection CN1 of the supply unit Pb1. The detection space FAc is located in the X2 direction relative to the supply unit Pb1. In the fourth embodiment, the supply unit Pb1 is an example of a "flow path".

[0190] The detection space FAc is defined by closing the first connection portion CN1 and the second connection portion CN2 with the fragile adhesive portion GLWc in the fourth embodiment. Similar to the second embodiment, a filter member may be provided to cover the first connection portion CN1 and the second connection portion CN2, and the fragile adhesive portion GLWc may be formed to cover this filter member.

[0191] In the initial state of the liquid spray head 30c, as shown in Figure 26, the fragile adhesive portion GLWc blocks the first connection portion CN1 and the second connection portion CN2. Therefore, in the initial state of the liquid spray head 30c, the detection space FAc is filled with air and no ink is present. Thus, in the initial state of the liquid spray head 30c, the detection space FAc is a sealed space. As the printing process is repeated, foreign matter is collected in the filter portion Fa, causing the flow resistance to continuously increase. When the fragile adhesive portion GLWc deteriorates and ink enters the detection space FAc, the detection space FAc functions as a bypass flow path. When the detection space FAc functions as a bypass flow path, the flow resistance decreases. Then, by repeating the printing process again, the flow resistance increases. Generally, when the flow resistance increases, the flow rate decreases. Therefore, in the fourth embodiment, the flow rate can be periodically measured by the flow meter 95, and the presence of ink in the detection space FAc can be detected by detecting that the flow rate has increased, i.e., that the flow resistance has decreased.

[0192] Let's return to the explanation in Figure 25. The flow meter 95 measures the flow rate of the flow path SF. For example, the flow meter 95 is installed between the supply tube Ta_in or between the discharge tube Ta_out. Also, in the example in Figure 25, the flow meter 95 is installed outside the liquid injection head 30c, but the flow meter 95 may also be installed inside the liquid injection head 30c. The flow meter 95 generates flow information QI indicating the measured flow rate and transmits the flow information QI to the control circuit 21c. The flow information QI can be said to be information regarding the presence or absence of ink in the detection space Fac.

[0193] 4-3. Operation of the fourth embodiment Figure 27 is a flowchart showing the operation of the inkjet system SYS in the fourth embodiment. The control circuit 21c functions as an acquisition unit 71c, an estimation unit 73c, and a notification unit 75 by executing the control program PM2c read from the memory circuit 22c. Below, only the differences from the flowchart shown in Figure 17 will be described.

[0194] In step SC2c, the control circuit 21c transmits the request signal RI to the flowmeter 95. After the processing of step SC2c is completed, the control circuit 21c waits for a response from the flowmeter 95.

[0195] When the flow meter 95 receives the request signal RI, the flow meter 95 measures the flow rate in the flow path SF in step SQ2. Then, in step SQ4, the flow meter 95 transmits the flow rate information QI to the control circuit 21c. After the processing in step SQ4 is completed, the flow meter 95 terminates the series of processes shown in Figure 27.

[0196] In step SC4c, the control circuit 21c functions as an acquisition unit 71c to acquire flow rate information QI from the flow meter 95. Next, in step SC6c, the control circuit 21c functions as an estimation unit 73c to estimate the degree of deterioration of the adhesive part GL57 based on the flow rate information QI. Specifically, the estimation unit 73c stores the flow rate information QI acquired by the acquisition unit 71c in the memory circuit 22c. For the sake of simplicity, the previously stored flow rate value stored in the memory circuit 22c may be referred to as the "previous flow rate value," and the flow rate value included in the flow rate information QI acquired by the acquisition unit 71c may be referred to as the "current flow rate value." The estimation unit 73c determines whether the current flow rate value is greater than or equal to the previous flow rate value plus a predetermined value. If the current flow rate value is less than the previous flow rate value plus a predetermined value, the estimation unit 73c estimates that the adhesive part GL57 is not deteriorated. On the other hand, if the current flow rate is greater than or equal to the previous flow rate plus a predetermined value, the estimation unit 73c estimates that the adhesive portion GL57 is deteriorating. The predetermined value is based on the value at which the flow rate increases when the detection space FAc functions as a bypass flow path. The predetermined value is stored in the memory circuit 22c in advance by the head maker based on experiments or experience.

[0197] In the fourth embodiment, the flow rate information QI can be said to be information regarding the presence or absence of ink in the detection space FAb.

[0198] 4-4. Summary of the Fourth Embodiment In the fourth embodiment described above, the detection space FAc is a bypass channel that branches off from the first connection part CN1 of the supply part Pb1 and rejoins the supply part Pb1 at a second connection part CN2 which is different from the first connection part CN1 of the supply part Pb1, and the fragile adhesive part GLWc blocks the first connection part CN1 and the second connection part CN2. According to the fourth embodiment, signs of ink leakage from the adhesive portion GL57 can be detected using the flow resistance, which changes based on the opening of the detection space FAc, which serves as a bypass flow path. Furthermore, according to the fourth embodiment, since the change in flow resistance can be detected by the flow meter 95, it is not necessary to install a new sensor near the detection space FAc to detect signs of ink leakage from the adhesive portion GL57.

[0199] Furthermore, in the third embodiment, the control circuit 21b functions as an acquisition unit 71b that acquires image information GI, which is information regarding the presence or absence of ink in the detection space FAb, and an estimation unit 73b that estimates the degree of deterioration of the adhesive part GL57 based on the image information GI acquired by the acquisition unit 71b. In addition, the control circuit 21b may also function as a notification unit 75.

[0200] In the fourth embodiment, the detection space FAc becomes a bypass flow path when it is opened. However, it does not have to be a bypass flow path; for example, as in the third embodiment, it may be formed by closing the opening of a recess provided on the side of the supply unit Pb1 with a fragile adhesive part GLW. However, in order for the flow meter 95 to detect changes in flow path resistance, it is necessary to set a space of a certain size or larger as the detection space FA, and it may be difficult to close a space of a certain size or larger with a fragile adhesive part GLW. On the other hand, if the detection space FAc is a bypass flow path, a space of a certain size or larger can be formed as the detection space FAc by closing the inlet and outlet of the bypass flow path with a fragile adhesive part GLW. Also, in the third embodiment, the detection space FA was formed by closing the opening of a recess provided on the side of the supply unit Pb1 with a fragile adhesive part GLW. However, as in the fourth embodiment, the detection space FAb may be formed so that it becomes a bypass flow path when it is opened.

[0201] In the fourth embodiment, the inkjet printer 100c had a flow meter 95, but it may have a pressure gauge instead of the flow meter 95. A pressure gauge can also detect changes in flow resistance.

[0202] 5. Fifth Embodiment In the fifth embodiment, a portion of the annular adhesive portion GL for the channel seal, which suppresses ink leakage from the channel SF to the outside, is formed as a fragile adhesive portion GLW. Furthermore, in the fifth embodiment, signs of ink leakage from the liquid spray head 30 can be detected in multiple stages. The fifth embodiment will be described below.

[0203] Figure 28 is a block diagram showing an example configuration of the inkjet printer 100d in the fifth embodiment. The inkjet printer 100d has a liquid jet head 30d instead of a liquid jet head 30a, a control circuit 21d instead of a control circuit 21a, a storage circuit 22c instead of a storage circuit 22a, and a measurement circuit 80d instead of a measurement circuit 80. The liquid jet head 30d is provided with a detection space FAd instead of a detection space FAa. The detection space FAd will be explained using Figures 28 and 29.

[0204] 5-1. Detection space FAd in the fifth embodiment Figures 29 and 30 are diagrams illustrating the detection space FAd. Figures 29 and 30 show an example in which the liquid injection head 30 shown in Figure 12 is replaced with a liquid injection head 30d, and the detection space FAd is provided within the region RG1 shown in Figure 12. Figure 29 shows an enlarged view of the region RG1 of the liquid injection head 30d. Figure 30 shows a cross-section when the liquid injection head 30d is broken along the cc line shown in Figure 29.

[0205] In the fifth embodiment, the detection space FAd has a first detection space FAd1 and a second detection space FAd2. Near the detection space FAd, as shown in Figure 27, a detection mechanism 60d is provided for determining whether or not ink is present in the detection space FAd. The detection mechanism 60d has a detection mechanism 60d1 used for determining whether or not ink is present in the first detection space FAd1, and a detection mechanism 60d2 used for determining whether or not ink is present in the second detection space FAd2. In the following description, the subscript 1 is added to the symbols of elements related to the detection mechanism 60d1, and the subscript 2 is added to the symbols of elements related to the detection mechanism 60d2. In a plan view, the elements related to the detection mechanism 60d2 have a structure that is almost identical when the elements related to the detection mechanism 60d1 are moved in the Y1 direction. Therefore, in the following description, the elements related to the detection mechanism 60d1 will be described in detail, and the descriptions of the elements related to the detection mechanism 60d2 will be omitted as appropriate.

[0206] The detection mechanism 60d1 includes detection wiring 61d1, 62d1, lead wiring 63d1, 64d1, and detection lead wire 65d1. Based on the magnitude of the current in the detection lead wire 65d1, it is possible to detect signs of ink leakage from the adhesive portion GL57. In the fifth embodiment, as in the second embodiment, it is assumed that the ink is conductive.

[0207] The lead wires 63d1, 64d1, and 65d1 are arranged on the surface SZ51 of the flow path plate Su5 facing the Z1 direction. In a plan view, the detection wire 65d1 is located within the first detection space FAd1, while the lead wires 63d1 and 64d1 are located outside the first detection space FAd1. The detection wire 65d1 is U-shaped. The lead wires 63d1 and 64d1 are arranged along the X axis. The X1 end of the lead wire 63d1 is connected to one end of the detection wire 65d1. The X1 end of the lead wire 64d1 is connected to the other end of the detection wire 65d1. The X2 end of the lead wire 63d1 is connected to the detection wire 61d1. The X2 end of the lead wire 64d1 is connected to the detection wire 62d1. The detection wires 61d1 and 62d1 are connected to the measurement circuit 80d via wiring components not shown.

[0208] The liquid injection head 30d has a flow path plate Su4d instead of the flow path plate Su4. In the flow path plate Su4d, a first detection space FAd1 and a second detection space FAd2 are formed by cutting out the surface SZ42 of the flow path plate Su4d facing the Z2 direction in the Z1 direction.

[0209] The horizontal channel Sh12 is surrounded by the adhesive portion GL45d in the fifth embodiment. In plan view, the shape of the adhesive portion GL45d is annular. In plan view, a portion of the adhesive portion GL45d is composed of the adhesive portion GLd, and the remainder of the adhesive portion GL45d is composed of the fragile adhesive portion GLWd. The fifth embodiment is a configuration for detecting signs of ink leakage from the adhesive portion GLd. In the examples of Figures 29 and 30, the X2, X1, and Y2 directions of the horizontal channel Sh12 are defined by the adhesive portion GLd, and the Y1 direction of the horizontal channel Sh12 is defined by the fragile adhesive portion GLWd.

[0210] In the examples in Figures 29 and 30, the embodiment for intentionally making the fragile adhesive portion GLWd more prone to deterioration than the adhesive portion GLd is the same as the first embodiment of the fragile adhesive portion GLW described in the first embodiment. However, in the fifth embodiment, in order to detect signs of ink leakage from the liquid spray head 30d in multiple stages, it is necessary that ink be present in the first detection space FAd1 and further in the second detection space FAd2 before ink leaks from the adhesive portion GLd. Therefore, the adhesive forming the fragile adhesive portion GLWd and the adhesive forming the adhesive portion GLd are of the same type, and the sum of the shortest distance LGWd1 and the shortest distance LGWd2 is shorter than the ink penetration distance Ld of the adhesive portion GLd. The shortest distance LGWd1 is the shortest distance from the portion where the fragile adhesive portion GLWd defines the horizontal flow path Sh12 to the Y2 end of the first detection space FAd1. The shortest distance LGWd2 is the shortest distance from the Y1 direction end of the first detection space FAd1 to the Y2 direction end of the second detection space FAd2. However, as an embodiment to intentionally make the fragile adhesive part GLWd more prone to deterioration than the adhesive part GLd, it is also possible to adopt an embodiment similar to the second embodiment of the fragile adhesive part GLW described in the first embodiment. In the fifth embodiment, the flow path plate Su4 corresponds to the "first flow path member", the flow path plate Su5 corresponds to the "second flow path member", the horizontal flow path Sh12 corresponds to "part of the flow path", the adhesive part GLd corresponds to the "first adhesive part", and the fragile adhesive part GLWd corresponds to the "second adhesive part".

[0211] The explanation returns to Figure 28. As part of the measurement process in the fifth embodiment, the measurement circuit 80d measures the current value between detection wiring 61d1 and 61d2 of the detection mechanism 60d1 and the current value between detection wiring 61d1 and 61d2 of the detection mechanism 60d2. The measurement circuit 80d transmits measurement information JId, which indicates the measurement result, to the control circuit 21d.

[0212] 5-2. Operation of the Fifth Embodiment Figure 31 is a flowchart showing the operation of the inkjet system SYS in the fifth embodiment. The control circuit 21d functions as an acquisition unit 71d, an estimation unit 73d, and a notification unit 75d by executing the control program PM2d read from the memory circuit 22d. Only the differences from Figure 21 will be explained below.

[0213] In step SC2d, the control circuit 21d transmits the request signal RI to the measurement circuit 80d. After the processing of step SC2d is completed, the control circuit 21d waits for a response from the measurement circuit 80d.

[0214] When the measurement circuit 80d receives the request signal RI, the measurement circuit 80d executes the measurement process according to the fifth embodiment in step SM2d. After the processing in step SM2d is completed, the measurement circuit 80d transmits measurement information JId, which indicates the measurement result, to the control circuit 21d in step SM4d. After the processing in step SM4d is completed, the measurement circuit 80d terminates the series of processes shown in Figure 31.

[0215] In step SC4d, the control circuit 21d functions as an acquisition unit 71d to acquire measurement information JId from the measurement circuit 80. Next, in step SC6d, the control circuit 21d functions as an estimation unit 73d to estimate the degree of deterioration of the adhesive part GLd based on the measurement information JId. In order to estimate the degree of deterioration of the adhesive part GLd, the memory circuit 22 stores a threshold value for the current value at which ink can be considered to be present in the detection space FAd. In the fifth embodiment, the estimation unit 73d estimates the degree of deterioration of the adhesive part GLd in three stages. The estimation unit 73d generates stage information indicating one of the three stages that indicate the degree of deterioration of the adhesive part GLd. The stage information is one of the following: first stage information indicating that the adhesive part GLd has not deteriorated, second stage information indicating that the adhesive part GLd has deteriorated, and third stage information indicating that the adhesive part GLd has deteriorated and ink will soon leak. The estimation unit 73d generates first-stage information if the current value between detection wirings 61d1 and 62d1 is below a threshold. The estimation unit 73d also generates second-stage information if the current value between detection wirings 61d1 and 62d1 is greater than a threshold, and the current value between detection wirings 61d2 and 62d2 is below a threshold. The estimation unit 73d also generates third-stage information if the current value between detection wirings 61d2 and 62d2 is greater than a threshold. The estimation unit 73d estimates the degree of deterioration of the adhesive GLd and generates stage information.

[0216] After the processing in step SC6d is completed, in step SC8d, the control circuit 21d determines, based on the estimation result, whether or not the user U should be notified. More specifically, the control circuit 21d determines that the user U should be notified if the stage information contains second-stage information or third-stage information.

[0217] If the determination result in step SC8d is positive, the control circuit 21d functions as a notification unit 75d in step SC10d to generate notification information CId based on the estimation result and notifies the user U of the generated notification information CId. Specifically, the control circuit 21d transmits the notification information CId to the processing unit 200, causing the processing unit 200 to notify the user U of the notification information CId. The notification information CId is information indicating the degree of signs of ink leakage from the liquid spray head 30d. For example, if the liquid spray head 30d is associated with the second stage information, the notification information CId is the first sign string, "There are signs of ink leakage from the liquid spray head. Please consider replacing the liquid spray head." Also, if the liquid spray head 30d is associated with the third stage information, the notification information CId is the second sign string, "The signs of ink leakage from the liquid spray head have increased. We recommend replacing the liquid spray head."

[0218] 5-3. Summary of the Fifth Embodiment In the fifth embodiment described above, when viewed in the direction along the Z-axis, which is the stacking direction of the flow path plates Su4 and Su5, the supply flow path Sh1 is surrounded by an annular adhesive portion GL45d, and when viewed in the direction along the Z-axis, a part of the adhesive portion GL45d is made up of adhesive portion GLd, and the remainder of the adhesive portion GL45d is made up of fragile adhesive portion GLWd. According to the fifth embodiment, it is possible to form a thinner fragile adhesive portion GLWd compared to the fragile adhesive portion GLW of the first to fourth embodiments. Specifically, the fragile adhesive portion GLW of the first to fifth embodiments is layered, with one surface of the fragile adhesive portion GLW of the first to fourth embodiments defining a part of the flow path SF, and the other surface defining the detection space FA. That is, almost the entire area of ​​both surfaces of the fragile adhesive portion GLW of the first to fourth embodiments is not in contact with the flow path members that constitute the flow path SF in the liquid injection head 30. Therefore, in order to easily form a thin fragile adhesive portion GLW, it is necessary to provide a filter member Fc, as in the second embodiment. On the other hand, both surfaces of the fragile adhesive portion GLWd in the fifth embodiment are in contact with the flow path members that constitute the flow path SF, and it is possible to form a thin fragile adhesive portion GLW without providing a filter member Fc.

[0219] Furthermore, in the fifth embodiment, signs of ink leakage from the liquid spray head 30d can be detected in multiple stages. User U can take action according to the notification information CId. Specifically, user U can use the liquid spray head 30d until just before it fails, while ensuring time to prepare a replacement liquid spray head 30d. For example, if the first sign string is notified to user U as notification information CId, user U orders a liquid spray head 30d from the head manufacturer. Then, if the second sign string is notified to user U as notification information CId, user U replaces the liquid spray head 30d with the liquid spray head 30d obtained from the head manufacturer.

[0220] Furthermore, in each of the embodiments from the first to the fourth, it is possible to detect signs of ink leakage from the liquid spray head 30 in multiple stages. For example, in the first embodiment, by providing a plurality of dummy individual flow paths RJD and varying the thickness of the fragile adhesive portion GLW that defines each dummy individual flow path RJD, it is possible to detect signs of ink leakage from the liquid spray head 30 in multiple stages. Similarly, in the second embodiment, by providing a plurality of detection spaces FAa within the liquid spray head 30a and varying the thickness of the fragile adhesive portion GLWa that closes each detection space FAa, it is possible to detect signs of ink leakage from the liquid spray head 30a in multiple stages. The third and fourth embodiments are similar to the second embodiment.

[0221] 6. Variations 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.

[0222] 6-1. First Variation In each of the embodiments described above, the first ink supplied to the liquid spray head 30 flows in the following order: the internal supply channel S1a, the internal supply channel R1a, the first liquid storage chamber Ra, the internal discharge channel R2a, and the internal discharge channel S2a, and is discharged from the liquid spray head 30. That is, in each of the embodiments described above, the individual channel RJ is not included in the path through which the ink circulates. However, this disclosure can also be applied in embodiments in which the individual channel RJ is included in the path through which the ink circulates. The first modified example will be described below.

[0223] Figure 32 is a cross-sectional view of the head unit Hnf in the first modified example when it is broken. The head unit Hn has N nozzles Nz for ejecting first ink and N nozzles Nz for ejecting second ink, but the head unit Hnf has Nf nozzles Nz for ejecting first ink. Nf is an integer of 1 or more. The head unit Hnf has a liquid ejection section Qf for ejecting first ink. The head unit Hnf has a nozzle plate 40f instead of a nozzle plate 40 and a communication plate 42f instead of a communication plate 42.

[0224] The nozzle plate 40f has Nf nozzles Nz formed on it. The Nf nozzles Nzf on the nozzle plate 40f are arranged along one nozzle row along the Y axis. The communication plate 42f is further provided with a nozzle channel RN that connects the first communication channel R3a and the first communication channel R3b. The nozzle channel RN is a space that extends along the X axis. One nozzle channel RN has one nozzle Nz.

[0225] The ink supplied to the first liquid storage chamber Ra is discharged to the second liquid storage chamber Rb via N individual channels RJf. In the following description, to distinguish the N individual channels RJf, they may be referred to as individual channel RJf[n1], where n1 is an integer between 1 and N. Elements related to individual channel RJf[n1] may also be referred to with [n1]. In the first modified example, the N individual channels RJf include Nf individual channels RJf that directly contribute to forming an image on the medium PP, and one or more dummy individual channels RJDf used as a detection space FA. The dummy individual channels RJDf will be described later in Figure 33. The number of nozzles Nz, Nf, is the number of individual channels RJf minus the number of dummy individual channels RJDf. Each of the N individual flow channels RJf is formed from a second connecting flow channel R4a, a pressure chamber Ca, a first connecting flow channel R3a, a nozzle flow channel RN, a first connecting flow channel R3b, a pressure chamber Cb, and a second connecting flow channel R4b.

[0226] Figure 33 is a diagram illustrating the dummy individual channel RJDf in the first modified example. In Figure 33, out of the N individual channels RJf, the Nth individual channel RJf[N] used as the detection space FAf, i.e., the dummy individual channel RJDf, in the first modified example is shown. In the example of Figure 33, pressure chambers Ca[N] and Cb[N] are dummy pressure chambers CD, and piezoelectric elements Ea[N] and Eb[N] are dummy piezoelectric elements ED.

[0227] The dummy individual channel RJD is partitioned from the first liquid storage chamber Ra by a fragile adhesive section GLWfa and from the second liquid storage chamber Rb by a fragile adhesive section GLWfb. The fragile adhesive section GLWfa is provided so as to block the opening 37Ka, i.e., at the Z2 end of the second communication channel R4a. The fragile adhesive section GLWfb is provided so as to block the opening 37Kb, i.e., at the Z2 end of the second communication channel R4b. In the following description, the fragile adhesive sections GLWfa and GLWfb may be referred to simply as fragile adhesive section GLWf without distinction.

[0228] As can be seen from Figure 33, the dummy individual channel RJDf does not have a dummy nozzle NzD. Therefore, the dummy individual channel RJDf is a sealed space. Because the dummy individual channel RJDf does not have a dummy nozzle NzD, it is possible to prevent ink from being forced from the dummy nozzle NzD into the dummy individual channel RJDf even though the fragile adhesive portion GLWf has not deteriorated. Therefore, according to the first modified example, the dummy individual channel RJDf can improve the accuracy of estimating the deterioration of the adhesive portion GL57 compared to the embodiment that has a dummy nozzle NzD.

[0229] In the first modified example, the dummy individual channel RJDf has two dummy pressure chambers CD, but it may have only one dummy pressure chamber CD. Also, in the first modified example, it is stated that the dummy individual channel RJDf does not have a dummy nozzle NzD, but the dummy individual channel RJDf may have a dummy nozzle NzD.

[0230] 6-2. Second Variation In the first embodiment, residual vibration information NEI was used to detect signs of ink leakage from the liquid spray head 30, but the invention is not limited to this. For example, the inkjet printer 100 may use an imaging device to detect whether an ink level, i.e., a meniscus, has formed on the dummy nozzle NzD. If a meniscus has formed on the dummy nozzle NzD, the inkjet printer 100 detects that there are signs of ink leakage from the liquid spray head 30. The inkjet printer 100 may also use an imaging device to detect whether or not ink has been ejected from the dummy nozzle NzD when a drive signal Com is supplied to the dummy piezoelectric element ED. In the third modification, the invention can also be applied to the case in the first modification where the dummy individual flow path RJDf has a dummy nozzle NzD. In the third modification, the invention can also be applied to the second modification and a heating element may be used.

[0231] 6-3. Third Variation In the second embodiment and the second modified example based on the second embodiment, the presence or absence of ink in the detection space FAa was detected using a detection wire 65 arranged in the detection space FAa, but the invention is not limited to this. For example, the detection space FAb may have a light-emitting unit on one of its bottom and top surfaces and a light-receiving unit on the other, and the presence or absence of ink in the detection space FAa may be detected based on whether or not the light-receiving unit receives light emitted by the light-emitting unit. The ink in the third modified example is assumed to have light-shielding properties. The light-emitting unit is composed of a light-emitting element such as an LED (Light Emitting Diode) that irradiates light in the natural light range. The light-receiving unit is composed of a light-receiving element such as a photodiode that has light-receiving sensitivity to light in the natural light range.

[0232] 6-4. Fourth Variation In each of the embodiments described above, the liquid spray head 30 may have a detection space FA corresponding to each of two or more adhesive portions GL. For example, the liquid spray head 30 may have a dummy individual flow path RJD, which is the detection space FA of the first embodiment, as a detection space FA for detecting signs of ink leakage from the adhesive portion GL in the head unit Hn, and a detection space FAa of the second embodiment for detecting signs of ink leakage from the adhesive portion GL in the flow path structure 33. In the fourth modified example, the estimation unit 73 estimates the degree of deterioration of the adhesive portion GL in the head unit Hn and the degree of deterioration of the adhesive portion GL in the flow path structure 33. In the fourth modified example, the notification unit 75 notifies the user U of a string of characters indicating the location of signs of ink leakage in the liquid spray head 30 as notification information CI. For example, if it is estimated that the adhesive portion GL in the flow path structure 33 has deteriorated, the notification information CI would be "There are signs of ink leakage in the flow path structure."

[0233] Furthermore, by providing detection spaces FA in the liquid spray head 30 that correspond to each of two or more adhesive parts GL, the head manufacturer may replace the part that shows signs of ink leakage. For example, suppose that detection spaces FA are provided that correspond to the adhesive parts GL in the flow path structure 33 within the liquid spray head 30 and the adhesive parts GL in each head unit Hn, and the notification unit 75 notifies the user U that the adhesive part GL in one of the head units Hn is deteriorating. In this case, the head manufacturer can extend the life of the liquid spray head 30 by replacing the head unit Hn in which the deterioration of the adhesive part GL was detected.

[0234] 6-5. Fifth Variation In each of the embodiments described above, the control circuit 21 functions as an acquisition unit 71, an estimation unit 73, and a notification unit 75, but it may also function as an acquisition unit 71 and an estimation unit 73, and not as a notification unit 75. For example, when a service support person from the head manufacturer visits the printer manufacturer or user U and performs the series of processes shown in Figure 17, the control circuit 21 may not function as a notification unit 75. The service support person provides appropriate support based on the estimation result estimated by the estimation unit 73. For example, if the estimation result indicates that there are signs of ink leakage at the adhesive part GL57, the service support person may suggest to user U that the liquid jet head 30 be replaced. [Explanation of symbols]

[0235] 3...Head module, 21,21a,21b,21c,21d...Control circuit, 22,22a,22b,22c,22d...Memory circuit, 30,30a,30b,30c,30d...Liquid injection head, 40,40f...Nozzle plate, 42,42f...Communication plate, 43...Pressure chamber substrate, 44...Vibrator, 50...Drive circuit, 55...Detection circuit, 60,60Ab,60d,60d1,60d2...Detection mechanism, 61,61d1,61d2,62,62d1,62d2...Detection wiring, 63...Internal wiring of component, 63d1...Output wiring, 64...Internal wiring of component, 64d1...Output wiring, 6 5,65d1…Detection wire, 71,71a,71b,71c,71d…Acquisition unit, 73,73a,73b,73c,73d…Estimation unit, 75,75d…Notification unit, 80,80d…Measurement circuit, 90…Imaging device, 95…Flow meter, 100,100a,100b,100c,100d…Inkjet printer, 113…Power supply circuit, 114…Drive signal generation circuit, 200…Processing device, 210…Control circuit, 242…Endless belt, 260…Input device, 270…Display device, 271…Cap, 272…Wiper, 290…Bus, 333…Laminate, C…Pressure chamber, CD …dummy pressure chamber, CI, CId…notification information, Ca, Cb…pressure chamber, E…piezoelectric element, ED…dummy piezoelectric element, Ea, Eb…piezoelectric element, FA, FAa, FAb, Fac, Fad…detection space, Fad1…first detection space, Fad2…second detection space, Faf…detection space, GI…image information, GL, GL12, GL23, GL34, GL45, GL45d, GL56, GL57…adhesive part, GLW, GLWa, GLWb, GLWc, GLWd, GLWf, GLWfa, GLWfb…weak adhesive part, GLd…adhesive part, JI, JId…measurement information, L57, Ld…i Ink penetration distance, LGW... Ink penetration distance, LGWd1, LGWd2... Shortest distance, LHa, LHb, LHd, LHs... Internal wiring, NEI... Residual vibration information, NES... Residual vibration signal, Nz, Nzf... Nozzle, NzD... Dummy nozzle, PP... Medium, PS... Inspection waveform, QI... Flow rate information, R1a, R1b... In-head supply channel, R2a, R2b... In-head discharge channel, R3a, R3b... First communication channel, R4a, R4b... Second communication channel, RC1, RCX2... Recess, RG1, RG2... Area, RI... Request signal, RJ, RJa, RJb, RJf... Individual channel, RJD,RJDf...Dummy individual channel, RN...Nozzle 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, S2a_out...Discharge port, S2b...In-structure discharge channel, S2b_out...Discharge port, SF...Channel, SI...Printing signal, SLa,SLb,SLs...Connection status specification signal, SWa,SWb,S Ws…Switch, SX2…Side, SZ1…Bottom, SZ42, SZ51…Surface, Sd…Individual designation signal, Sh1…Supply channel, Sh11…Vertical channel, Sh12…Horizontal channel, Sh13…Vertical channel, Sn…In-structure channel, Su, Su1, Su2, Su2c, Su3, Su4, Su4b, Su4d, Su5, Su5a…Channel plate, TR…Transparent member, Vout…Detection signal, dCom…Waveform designation signal.

Claims

1. Multiple nozzles for spraying liquid, A first flow path member that defines a portion of the flow path communicating with the plurality of nozzles, A second flow channel member that defines a part of the aforementioned flow channel, A first adhesive portion for liquid-tightly connecting a part of the flow path of the first flow path member and a part of the flow path of the second flow path member, An adhesive portion defining the inner wall of the flow channel, comprising a second adhesive portion defining a detection space separated from the flow channel, which is a space for detecting the degree of deterioration of the first adhesive portion, A liquid spray head characterized by having the following features.

2. The adhesive forming the second adhesive portion and the adhesive forming the first adhesive portion are of the same type. The liquid spray head according to feature 1.

3. The shortest distance from the portion defining the flow path of the second adhesive portion to the portion defining the detection space is shorter than the shortest distance from the portion defining the flow path of the first adhesive portion to the end opposite to the portion defining the flow path. The liquid spray head according to feature 2.

4. The liquid resistance of the second adhesive portion is lower than that of the first adhesive portion. The liquid spray head according to feature 1.

5. A wire for detecting the degree of deterioration of the first adhesive portion is arranged within the detection space. The liquid spray head according to feature 1.

6. The flow path includes a plurality of individual flow paths communicating with each of the plurality of nozzles, and a common liquid chamber connected to the plurality of individual flow paths in common. The second adhesive portion partitions at least a portion of the dummy individual flow path as the detection space with respect to the common liquid chamber. The liquid spray head according to feature 1.

7. The liquid spray head forms an image by spraying liquid onto a medium. The system further comprises a dummy piezoelectric element that does not directly contribute to forming the aforementioned image, The dummy individual channel includes a dummy pressure chamber to which pressure is applied by the dummy piezoelectric element. The liquid spray head according to feature 6.

8. The detection space is a sealed space. The liquid spray head according to feature 1.

9. The detection space is defined by closing the opening of a recess provided on the bottom surface that defines the flow path with the second adhesive portion. The opening of the recess opens in the direction opposite to the direction in which the nozzle opens. The liquid spray head according to feature 8.

10. Viewed in the stacking direction of the first channel member and the second channel member, a portion of the channel is surrounded by an annular adhesive portion. Viewed in the stacking direction, a portion of the annular adhesive portion is formed by the first adhesive portion, and the remaining portion of the annular adhesive portion is formed by the second adhesive portion. The liquid spray head according to feature 8.

11. The member that defines a part of the detection space is translucent, The liquid spray head according to feature 8.

12. The detection space is a bypass channel that branches off from the first connection point of the channel and rejoins the channel at a second connection point different from the first connection point of the channel. The second adhesive portion closes the first connection portion and the second connection portion. The liquid spray head according to feature 8.

13. A liquid spray head according to any one of claims 1 to 12, An acquisition unit that acquires information regarding the presence or absence of liquid in the detection space, An estimation unit estimates the degree of deterioration of the first adhesive portion based on the information acquired by the acquisition unit, A liquid injection device characterized by being equipped with the following features.

14. The system further includes a notification unit that prompts the replacement of the liquid spray head when the estimation unit estimates that the first adhesive portion is deteriorated. The liquid injection device according to feature 13.

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