Liquid ejection head and liquid ejection apparatus

Abstract

To provide a liquid ejection head capable of suppressing occurrence of ejection failure.SOLUTION: The liquid ejection head includes a first substrate having an ejection orifice from which a liquid is ejected, a liquid chamber communicating with the ejection orifice and having a communication port 15, and an energy generating element 13 overlapping with the ejection orifice in a first direction and generating energy for ejecting the liquid in the liquid chamber from the ejection orifice, a second substrate having a flow path communicating with the communication port 15 of the liquid chamber and joined to the first substrate, and a detection wiring 301 provided between the energy generating element 13 and the communication port 15 in a second direction intersecting the first direction and configured to detect that the liquid has entered.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection head and a liquid ejection apparatus. [Background technology]

[0002] Conventionally, a liquid ejection device is known that includes a liquid ejection head that ejects a liquid such as ink to record an image on a recording medium. In the liquid ejection head, multiple substrates are bonded together with an adhesive to form an ink flow path that spans the substrates. Repeated ejection operations using a liquid ejection head with such a configuration over a long period of time can cause the bond between the substrates to change, resulting in peeling at the interface between the substrate and the adhesive. This can lead to ink seeping in from the flow path, damaging the ejection elements and electrical wiring arranged on the substrate, potentially resulting in ejection defects.

[0003] Patent Document 1 discloses a configuration in which, in order to prevent ink from entering, a metal structure is provided in a position surrounding a communication port that serves as a flow path, and an annular wall portion that further protrudes upward is provided. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6213335 Summary of the Invention [Problem to be solved by the invention]

[0005] However, no matter what the configuration, it is difficult to completely prevent ink from seeping in. In the configuration described above, if ink seeps in through the joint, there is a risk of ejection failure occurring.

[0006] The present invention has been made in view of the above-mentioned problems, and has an object to provide a liquid ejection head that can suppress the occurrence of ejection defects. [Means for solving the problem]

[0007] In order to achieve the above object, the liquid ejection head of the present invention comprises: a discharge port through which the liquid is discharged; a first substrate having a liquid chamber communicating with the ejection port, the liquid chamber having a communication port through which liquid supplied to the liquid chamber passes, and an energy generating element that generates energy for ejecting the liquid in the liquid chamber from the ejection port, the energy generating element being arranged at a position overlapping the ejection port when viewed in a first direction; a second substrate having a flow path communicating with the communication port of the liquid chamber and bonded to the first substrate; a detection wiring provided between the energy generating element and the communication port in a second direction intersecting the first direction, for detecting the intrusion of a liquid; The present invention is characterized by comprising: [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a liquid ejection head that can suppress the occurrence of ejection defects. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view showing a schematic configuration of a liquid ejection device according to an embodiment. [Figure 2] 1 is a perspective view showing a schematic configuration of a liquid ejection head according to an embodiment. [Figure 3] FIG. 2 is a block diagram showing the configuration of a control system of the liquid ejection device according to the embodiment. [Figure 4] FIG. 2 is a cross-sectional view of a substrate for a liquid ejection head according to the embodiment. [Figure 5] FIG. 2 is a plan view of an element substrate according to the first embodiment. [Figure 6] FIG. 1 is a cross-sectional view of a substrate for a liquid ejection head according to a first embodiment. [Figure 7] FIG. 10 is a plan view of an element substrate according to a modified example. [Figure 8] FIG. 10 is a plan view of an element substrate according to a second embodiment. [Figure 9] FIG. 10 is a cross-sectional view of a liquid ejection head substrate according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the components described in the following embodiments are merely examples, and the configuration and various conditions of the device to which the present invention is applied can be modified or changed as appropriate without departing from the spirit of the present invention, and the present invention is not limited to the following embodiments. For example, the dimensions, materials, shapes, and relative positions of the components described in the following embodiments can be modified as appropriate depending on the configuration and various conditions of the device to which the present invention is applied, and unless otherwise specified, the present invention is not limited to the following embodiments.

[0011] In this specification, "printing" (sometimes called "printing," "recording," or "printing") refers not only to the formation of meaningful information such as characters and figures, but also to the formation of meaningful or insignificant information. Furthermore, it broadly refers to the formation of images, designs, patterns, etc. on a recording medium, or the processing of a medium by discharging a liquid, regardless of whether the information is visible to humans or not.

[0012] <Embodiment> As an embodiment, an example will be described in which the present invention is applied to a liquid ejection device that ejects ink as a recording liquid onto a recording medium such as paper to record an image, and a liquid ejection head provided in the liquid ejection device. However, the present invention can also be applied to liquid ejection heads that eject liquids other than ink, and other liquid ejection devices.

[0013] (Liquid discharge device) A liquid ejection apparatus 500 according to an embodiment will be described. Fig. 1 is a perspective view showing a schematic configuration of the liquid ejection apparatus 500. Fig. 2 is a perspective view showing a schematic configuration of a liquid ejection head 42 provided in the liquid ejection apparatus 500. Fig. 3 is a block diagram showing the configuration of a control system for the liquid ejection apparatus 500.

[0014] The liquid ejection device 500 is a recording device that includes a liquid ejection head 42 that ejects liquid (ink) toward a recording medium P, and a carriage 41 to which the liquid ejection head 42 is detachably attached. The carriage 41 moves in a scanning direction A while being supported by a guide shaft 502. As the carriage 41 moves, the liquid ejection head 42 also moves in the scanning direction A together with the carriage 41.

[0015] The liquid ejection device 500 includes a transport unit that transports the recording medium P in a transport direction B that intersects with the scanning direction A. The transport unit is composed of transport members such as a transport roller 411 and a transport roller 511. The transport rollers 411 and 511 are rotated by a transport motor 70 to transport the recording medium P in the transport direction B. In this embodiment, the scanning direction A and the transport direction B are substantially perpendicular to each other.

[0016] In the liquid ejection device 500, the control unit 52 drives the carriage motor 24 to perform a recording operation in which ink is ejected onto the recording medium P in accordance with the recording data. As a result, one band of image is recorded on the recording medium P. Thereafter, the control unit 52 drives the transport motor 70 to perform a transport operation in which the recording medium P is transported in the transport direction B by a distance equivalent to one band. In this way, the liquid ejection device 500 forms a recorded image on the recording medium P by repeatedly alternately performing the recording operation and the transport operation.

[0017] The liquid ejection device 500 also includes a recovery unit 34 for performing maintenance on the liquid ejection head 42 at a home position where the liquid ejection head 42 is located at one end in the scanning direction A. The recovery unit 34 includes a cap member 36 for protecting the liquid ejection head 42, and a pump 38 that generates negative pressure within the cap member 36 by suction. Four liquid ejection heads 42 are arranged on the carriage 41, and each is configured to be able to eject cyan, magenta, yellow, and black ink. A liquid ejection head substrate 1 and an electrical wiring member 44 for supplying recording data, power, and the like are attached to the liquid ejection head 42.

[0018] (Control system) Next, a control system of the liquid ejection device 500 will be described with reference to FIG. 3. The liquid ejection device 500 is connected to a separately provided host device 50 via an interface (hereinafter referred to as I / F) 48. The liquid ejection device 500 transmits and receives various information to and from the host device 50 via this I / F 48. Specifically, the liquid ejection device 500 receives recording commands and image data from the host device 50 and transmits status information of the liquid ejection device 50 to the host device 50 via the I / F 48. The host device 50 may be a general-purpose personal computer or any known device such as a digital camera, scanner, or mobile terminal. When a recording command is generated in the host device 50, the recording command is input to the liquid ejection device 500 via the I / F 48 together with image data.

[0019] The overall operation of the liquid ejection device 500 is controlled by a control unit 52. The control unit 52 includes an MPU 54, a ROM 56, a DRAM 58, an EEPROM 60, and a gate array (hereinafter referred to as a GA) 62. The EEPROM 60 is a memory for recording various information required for the liquid ejection device 500 when the power is turned on again, even if the power is turned off. The GA 62 also controls data transfer between the I / F 48 under instructions from the MPU 54.

[0020] The MPU 54 performs various processes using the DRAM 58 as a work area in accordance with the programs and parameters stored in the ROM 56. For example, the MPU 54 drives the carriage motor 24 via a CR motor driver 64 connected to the control unit 52 to move the carriage 41 in the scanning direction A. During the recording operation, recording data is transferred from the DRAM 58 to the liquid ejection head 42 via a head driver 66 connected to the control unit 52, and one band of image is recorded on the liquid ejection head 42.

[0021] Furthermore, every time one band of image is recorded, the MPU 54 drives the conveying motor 70 via the LF motor driver 68 connected to the control unit 52, and causes the conveying rollers 411, 511 to convey the recording medium P a predetermined distance in the conveying direction B. The liquid ejection device 500 alternately repeats the recording operation under the control of the carriage motor 24 and liquid ejection head 42 by the MPU 54 and the conveying operation under the control of the conveying rollers 411, 511, to record the image data received from the host device 50 on the recording medium P.

[0022] Furthermore, the MPU 54 drives a recovery motor 74 via a recovery motor driver 72 connected to the control unit 52, at a timing such as after recording of one page of image has been completed, to perform suction recovery processing on the liquid ejection head 42. That is, the recovery motor 74 includes a motor that drives the pump 38 and a motor that drives (e.g., raises and lowers) the cap member 36.

[0023] Furthermore, the MPU 54 adjusts the potential of the detection wiring provided in the liquid ejection head 42 via the electric field adjuster 76 connected to the control unit 52. Furthermore, the measurement unit 82 adjusts the potential of the detection wiring provided in the liquid ejection head 42. In step 52, the resistance value of the wiring circuit for ink intrusion detection is measured, and the measurement result is output to the control unit 52. The detection wiring for ink intrusion detection will be described later.

[0024] Various parameters used by the MPU 54 to perform various controls are stored in the ROM 56. Examples of such parameters include the shape of the voltage pulse applied to the piezoelectric element of the liquid ejection head 42, the transport speed of the recording medium P, and the movement speed of the carriage 41.

[0025] (liquid ejection head) Next, the configuration of the liquid ejection head 42 will be described. Fig. 4 is a cross-sectional view of the liquid ejection head substrate 1 of the liquid ejection head 42 according to the embodiment. The liquid ejection head substrate 1 is configured by laminating an element substrate 8 (first substrate), a flow path forming substrate 6 (second substrate), and a nozzle substrate 3 (third substrate). When the liquid ejection head 42 is in an in-use position, the nozzle substrate 3, element substrate 8, and flow path forming substrate 6 are laminated in this order from the bottom up.

[0026] In the following description, the stacking direction of the element substrate 8, the flow path forming substrate 6, and the nozzle substrate 3 is referred to as the first direction D1. A predetermined direction intersecting the first direction D1 is referred to as the second direction D2, and a direction intersecting the first direction D1 and the second direction D2 is referred to as the third direction D3. In the embodiment, the first direction D1, the second direction D2, and the third direction D3 are perpendicular to one another. FIG. 4 shows a cross section of the liquid ejection head substrate 1 as viewed in the third direction D3. In the following description, the positional relationship of each component will be described based on an attitude in which the first direction D1 is parallel to the vertical direction, the flow path forming substrate 6 is positioned above the element substrate 8, and the nozzle substrate 3 is positioned below the element substrate 8, as shown in FIG.

[0027] The nozzle substrate 3 is formed with ejection ports 4 through which ink is ejected. A plurality of ejection ports 4 are formed in the nozzle substrate 3, and function as nozzles for ejecting ink toward the recording medium P. The direction in which ink is ejected from the ejection ports 4 is approximately parallel to the first direction D1.

[0028] A pressure chamber 11 is formed in the element substrate 8. The pressure chamber 11 is a liquid chamber (flow path) that communicates with the ejection port 4 and through which ink ejected from the ejection port 4 passes.

[0029] The flow channel forming substrate 6 is formed with a common flow channel 9, individual flow channels 10, and cavities 12. The individual flow channels 10 are flow channels that communicate with the pressure chambers 11, and the common flow channel 9 is a flow channel that communicates with the individual flow channels 10. The cavity 12 is a space in which a piezoelectric element 13 is disposed, and is provided at a position that overlaps with the individual flow channels 10 when viewed in the second direction D2.

[0030] The liquid ejection head substrate 1 is formed with a liquid flow path that is made up of a common flow path 9, individual flow paths 10, pressure chambers 11, and ejection ports 4. Ink supplied from a liquid storage section or the like passes through the common flow path 9, individual flow paths 10, and pressure chambers 11 in this order inside the liquid ejection head 42, and is ejected from the ejection ports 4.

[0031] A diaphragm 7 is provided on the element substrate 8. The diaphragm 7 is an insulating film made of an elastic material such as silicon oxide. The diaphragm 7 is provided on the outermost surface of the element substrate 8 and is bonded to the flow path forming substrate 6. The diaphragm 7, together with the pressure chamber wall 14 of the element substrate 8, constitutes the inner wall surface of the pressure chamber 11. In other words, the diaphragm 7 has a surface facing the inside of the pressure chamber 11 and a surface facing the outside of the element substrate 8 (the flow path forming substrate 6 side). The surface of the diaphragm 7 facing the flow path forming substrate 6 side is the outermost surface of the element substrate 8 and is the bonding surface that is bonded to the flow path forming substrate 6.

[0032] Piezoelectric elements 13 corresponding to the pressure chambers 11 are provided on the surface of the vibration plate 7 facing the flow path forming substrate 6. When the element substrate 8 and the flow path forming substrate 6 are bonded together, the piezoelectric elements 13 are disposed inside cavities 12 formed in the flow path forming substrate 6.

[0033] When power is applied, the piezoelectric element 13 deforms so as to bend toward the inside of the pressure chamber 11. As the piezoelectric element 13 deforms, the vibration plate 7 deforms integrally with the piezoelectric element 13, thereby reducing the volume of the pressure chamber 11 and applying pressure to the ink within the pressure chamber 11. When pressure is applied to the ink within the pressure chamber 11, some of the ink is ejected from the ejection port 4 as droplets (ink droplets). In other words, the piezoelectric element 13 is an energy generating element for ejecting ink within the pressure chamber 11 (liquid chamber) from the ejection port 4. The piezoelectric element 13 is provided corresponding to the ejection port 4 and is positioned so as to overlap with the ejection port 4 when viewed in the first direction D1.

[0034] Communication ports 15 for connecting the pressure chambers 11 to the individual flow channels 10 are formed on the surface of the element substrate 8 on which the piezoelectric elements 13 are formed, i.e., on the surface of the vibration plate 7. The element substrate 8 and the flow channel forming substrate 6 are aligned and bonded with an adhesive so that the communication ports 15 of the element substrate 8 communicate with the individual flow channels 10 of the flow channel forming substrate 6. At this time, the outer edge of the communication ports 15 is bonded to the flow channel forming substrate 6.

[0035] The communication port 15 is an opening (flow path) formed in the vibration plate 7, and other members such as the pressure chamber wall 14 do not form the wall portion of the communication port 15. The vibration plate 7 is generally made thin to increase displacement efficiency, so it has low mechanical strength and is easily damaged by external forces. An example of an external force is deformation of the vibration plate 7 due to driving of the piezoelectric element 13. If the vibration plate 7 is damaged, ink will enter the inside of the element substrate 8 through the communication port 15.

[0036] Alternatively, a potential may be applied due to a sudden leak in the flow path forming substrate 6 or element substrate 8. Generally, a protective film is formed on the inner walls of the ink flow paths, but if there is a defect in the ink flow path protective film, ink may enter and an electrochemical reaction may occur, causing an anodic reaction in the layer around the communication opening, resulting in oxidation or dissolution.

[0037] If the joints around the communication opening 15 are damaged or dissolved due to the events described above, the ink will penetrate into the inside of the element substrate 8 and come into contact with the piezoelectric elements 13 formed on the element substrate 8 and the drive wiring for driving the piezoelectric elements 13. This will cause corrosion due to an electrochemical reaction, resulting in ejection defects.

[0038] The piezoelectric elements 13 and drive wiring formed on the element substrate 8 are covered with a protective film. However, the piezoelectric elements 13 and drive wiring are formed on the bonding surface of the element substrate 8 with the flow path forming substrate 6, and it is not anticipated that ink will infiltrate into the cavities 12, etc. in the first place. Therefore, there is a risk that the protective film alone will not be sufficient to protect the piezoelectric elements 13 and drive wiring from ink that invades in an unexpected event.

[0039] To prepare for such a situation, it is preferable to be able to detect ink intrusion onto the element substrate 8 before the ink reaches the piezoelectric elements 13 or the drive wiring. Below, configurations for detecting ink intrusion that can be applied to the embodiments will be described in several examples.

[0040] <First Example> A first embodiment having an ink intrusion detection configuration will be described using Figures 5 and 6. Figure 5 is a plan view showing the periphery of a portion of a piezoelectric element 13 on an element substrate 8 according to the first embodiment, as viewed in a first direction D1. Note that in Figure 5, some components such as a protective film are omitted in order to clearly show the positional relationship of components such as wiring. Also, in Figure 5, the position of a cavity 12 in a flow path forming substrate 6 is indicated by a dotted line.

[0041] The element substrate 8 is provided with piezoelectric elements 13, the number of which corresponds to the number of ejection ports 4 of the nozzle substrate 3. When viewed in the first direction D1, a communication port 15 opens at a position aligned in the second direction D2 relative to each piezoelectric element 13. The cross-sectional shape of the communication port 15 (the shape when viewed in the first direction D1) is a rectangle with the second direction D2 as the longitudinal direction. Figure 5 shows three piezoelectric elements 13 and three communication ports 15 aligned in the third direction D3.

[0042] A first drive wiring 112 and a second drive wiring 113 are connected to the piezoelectric element 13 as drive wirings for driving the piezoelectric element 13. When viewed in the first direction D1, the piezoelectric element 13 has a rectangular shape with long sides parallel to the second direction D2 and short sides parallel to the third direction D3. The first drive wiring 112 is connected to an end of the piezoelectric element 13 that is closer to the communication opening 15 in the longitudinal direction. The second drive wiring 113 is connected to an end of the piezoelectric element 13 that is farther from the communication opening 15 in the longitudinal direction.

[0043] A first drive wiring 112 or a second drive wiring 113 extends between two piezoelectric elements 13 adjacent to each other in the third direction D3. Fig. 5 illustrates not only the drive wiring connected to the illustrated piezoelectric elements 13 but also drive wiring connected to piezoelectric elements 13 not shown. These drive wirings extend so as to pass between two communication ports 15 adjacent to each other in the third direction D3.

[0044] In this way, the piezoelectric element 13 and the first drive wiring 112 are adjacent to the communication opening 15 in the second direction D2, and the first drive wiring 112 and the second drive wiring 113 are adjacent to the communication opening 15 in the third direction D3. If ink infiltrates through the communication opening 15 into the wiring arranged around the communication opening 15 or the piezoelectric element 13, this could lead to ejection defects. Therefore, in the first embodiment, a detection wiring is provided around the communication opening 15 to detect the infiltration of ink.

[0045] In the first embodiment, the liquid ejection head substrate 1 includes first detection wiring 301 and second detection wiring 302 as detection wirings for detecting ink intrusion. The first detection wiring 301 and second detection wiring 302 are arranged parallel to each other at a predetermined distance. In the first embodiment, the first detection wiring 301 and second detection wiring 302 pass around the periphery of the multiple communication ports 15 while maintaining a parallel positional relationship, and are each connected to separate electrode pads. In other words, the first detection wiring 301 and second detection wiring 302 are electrically insulated from each other.

[0046] The liquid ejection head 42 also includes a measurement unit 82 as a measuring device capable of measuring the resistance value of a circuit including the first detection wiring 301 and the second detection wiring 302. The measurement unit 82 is connected to each of the first detection wiring 301 and the second detection wiring 302 via electrode pads. The measurement unit 82 may be provided on the main body side of the liquid ejection device 500, rather than on the liquid ejection head 42. In the first embodiment, the measurement unit 82 measures the resistance value between the first detection wiring 301 and the second detection wiring 302.

[0047] When ink has not entered between the first detection wiring 301 and the second detection wiring 302, the first detection wiring 301 and the second detection wiring 302 are in an open state. Therefore, the resistance value measured by the measurement unit 82 via the electrode pad is sufficiently large. This resistance value is used as the reference resistance value.

[0048] On the other hand, if ink has entered between the first detection wiring 301 and the second detection wiring 302, the resistance value will be lower than the reference resistance value. Therefore, according to the configuration of the first embodiment, the resistance value between the first detection wiring 301 and the second detection wiring 302 is continuously measured, and if the resistance value decreases, it can be determined that ink has entered the element substrate 8.

[0049] That is, according to this embodiment, the ink intrusion can be detected at the moment when the ink comes into contact with the detection wiring, and the ejection operation can be stopped and the user can be requested to replace the head before an ejection failure occurs.

[0050] A switch 83 is also provided in the circuit configured by the first detection wiring 301, the second detection wiring 302, and the measurement unit 82. The switch 83 may be configured to be open while the liquid ejection head 42 is printing and to be closed when measuring the resistance value. Alternatively, the switch 83 may be configured to be always closed, and the measurement unit 82 may always measure the resistance value.

[0051] The determination unit that determines that ink has infiltrated may be the control unit 52 of the liquid ejection device 500, or may be provided separately in the liquid ejection head 42. The determination unit may determine that ink has infiltrated when the resistance value acquired by the measurement unit 82 falls below a reference resistance value, or may determine that ink has infiltrated when the resistance value falls below a predetermined threshold value.

[0052] Fig. 6 is a view of the liquid ejection head substrate 1 taken along the line AA (a cross section perpendicular to the third direction D3) in Fig. 5. Fig. 6 shows the flow path forming substrate 6, and the vibration plate 7 and piezoelectric element 13 of the element substrate 8, of the liquid ejection head substrate 1.

[0053] The piezoelectric element 13 is composed of a lower electrode 106 in contact with the diaphragm 7, a piezoelectric film 107 disposed on the lower electrode 106, and an upper electrode 108 disposed on the piezoelectric film 107. The piezoelectric film 107 and the upper electrode 108 are patterned into a rectangular shape that is long in the second direction D2. Furthermore, the piezoelectric element 13 is covered with an insulating layer 109 for the purpose of moisture prevention and insulation.

[0054] In order to apply a voltage to the upper electrode 108 and the lower electrode 106, two openings, opening 110 and opening 111, are provided in the insulating layer 109. The lower electrode 106 is an electrode layer to which a first drive wiring 112 is connected via the opening 110. The upper electrode 108 is an electrode layer to which a second drive wiring 113 is electrically connected via the opening 111. The first drive wiring 112 and the second drive wiring 113 are each connected to a mounting terminal (not shown). Furthermore, the piezoelectric element 13, the first drive wiring 112, and the second drive wiring 113 are covered on top of the insulating layer 109 with a protective layer 114 for the purpose of moisture prevention and insulation. In other words, the protective layer 114 is stacked on top of the insulating layer 109, and the insulating layer 109 is covered with the protective layer 114.

[0055] The communication opening 15 formed at the interface between the element substrate 8 and the flow path forming substrate 6 is a location that is likely to be the starting point for ink penetration. Therefore, it is desirable to arrange the detection wiring for ink detection around it. In the first embodiment, the first detection wiring 301 and the second detection wiring 302 are arranged to surround the rectangular communication opening 15 except for a portion when viewed in the first direction D1. A gap E of the communication opening 15 that is not surrounded by the detection wiring is provided on the opposite side of the communication opening 15 from the piezoelectric element 13 in the second direction D2, i.e., in a portion corresponding to the side farther from the piezoelectric element 13. The detection wiring arranged to surround one communication opening 15 extends to similarly surround that communication opening 15 and the communication opening 15 adjacent to it in the third direction D3.

[0056] Furthermore, when viewed in the first direction D1, individual flow paths 10 are formed at positions overlapping with the communication openings 15. The first detection wiring 301 and the second detection wiring 302 are disposed on the vibration plate 7 on which the communication openings 15 are formed, and the individual flow paths 10 are also disposed above the communication openings 15. In other words, when viewed in the first direction D1, the first detection wiring 301 and the second detection wiring 302 surround the individual flow paths 10 except for a portion thereof.

[0057] In the first embodiment, a part of the communication opening 15 is not surrounded by the detection wiring. The entire periphery of communication opening 15 may be surrounded by the detection wiring. To achieve a configuration in which the entire periphery of communication opening 15 is surrounded, for example, the detection wiring arranged around communication opening 15 and the connection wiring extending in third direction D3 and connecting the detection wirings to each other may be formed in different layers. More specifically, the connection wiring may be formed in a layer below protective layer 114, and a portion of protective layer 114 may be opened so that the connection wiring is connected to first detection wiring 301 and second detection wiring 302 through the opening.

[0058] Furthermore, the detection wiring does not necessarily have to be arranged to surround the communication opening 15. If the only purpose is to prevent ink from entering the piezoelectric element 13, the first detection wiring 301 and the second detection wiring 302 may be provided between the piezoelectric element 13 and the communication opening 15 in the second direction D2. In other words, if the ink entry path is limited, the detection wiring may be arranged between the piezoelectric element 13 and the communication opening 15 somewhere along the entry path. Furthermore, to prevent ink from entering the drive wiring, the detection wiring may be arranged between the drive wiring and the communication opening 15.

[0059] Furthermore, in the first embodiment, the first detection wiring 301 and the second detection wiring 302 are formed on the protective layer 114, i.e., on the bonding surface with the flow path forming substrate 6, but the present invention is not limited to this configuration. In other words, the detection wirings only need to be disposed in positions where they can detect the intrusion of ink before the ink reaches the piezoelectric elements 13 or the drive wirings. Specifically, for example, the detection wirings may be formed between the protective layer 114 and the insulating layer 109, or between the vibration plate 7 and the insulating layer 109.

[0060] In the first embodiment, because ink penetration is detected by resistance changes, the first detection wiring 301 and the second detection wiring 302 must be made of a material that does not undergo a resistance change even when the wiring itself comes into contact with ink. For example, a corrosion-resistant material that does not dissolve when it comes into contact with ink or other liquids is preferable, and specifically, noble metals such as Ta, Nb, Au, Ir, and Pt are preferably used, but are not limited to these. Furthermore, the first detection wiring 301 and the second detection wiring 302 may be made of different materials as long as they satisfy the above conditions.

[0061] Furthermore, in the first embodiment, a pair of first detection wiring 301 and second detection wiring 302 is provided, but it is also possible to provide more first detection wiring 301 and second detection wiring 302. Fig. 7 is a plan view showing the periphery of a part of a piezoelectric element 13 of an element substrate 8 according to a modified example, when the element substrate 8 is viewed in the first direction D1.

[0062] In this modified example, different first detection wirings 301 and second detection wirings 302 are arranged around two communication ports 15 sandwiching the second drive wiring 113. By providing multiple first detection wirings 301 and second detection wirings 302 in this manner, ink intrusion can be detected for each block, i.e., for each predetermined range. With this configuration, when ink intrusion is detected in a certain block, the ejection in that block is stopped and the ejection signal is changed to compensate for the ink intrusion in another block, allowing printing to continue. In other words, by providing multiple detection wirings corresponding to each of the multiple piezoelectric elements 13 and multiple measurement units 82 corresponding to each of the multiple detection wirings, when ink intrusion is detected, printing operations can be continued while suppressing the occurrence of printing defects due to ejection defects.

[0063] As described above, according to the configuration of the first embodiment, it is possible to detect the intrusion of ink into the element substrate 8, thereby suppressing the occurrence of ejection defects and preventing the deterioration of the quality of the product.

[0064] <Second Example> A second embodiment having an ink intrusion detection configuration will be described with reference to Figures 8 and 9. Figure 8 is a plan view showing the periphery of a piezoelectric element 13 of a part of an element substrate 8 according to the second embodiment. 8 is a view of the plate 8 as viewed in the first direction D1. Note that in FIG. 8, some components such as protective films are omitted in order to clearly show the positional relationships of the wiring and other components. Also in FIG. 8, the position of the cavity 12 in the flow path forming substrate 6 is indicated by a dotted line. FIG. 9 is a view of the liquid ejection head substrate 1 as viewed at cross section BB in FIG. 8 (cross section perpendicular to the third direction D3). FIG. 8 shows the flow path forming substrate 6 and the vibration plate 7 and piezoelectric element 13 of the element substrate 8, which are included in the liquid ejection head substrate 1.

[0065] In the second embodiment, a single detection wire 303 is provided instead of the first detection wire 301 and the second detection wire 302 of the first embodiment. The detection wire 303 is made of a metal material that dissolves when it comes into contact with a liquid (ink).

[0066] The detection wiring 303 is arranged to surround the rectangular communication opening 15 except for a portion thereof when viewed in the first direction D1. A gap E of the communication opening 15 that is not surrounded by the detection wiring 303 is provided on the opposite side of the communication opening 15 from the piezoelectric element 13 in the second direction D2, i.e., on a portion corresponding to the side farthest from the piezoelectric element 13. The detection wiring arranged to surround one communication opening 15 further extends to similarly surround that communication opening 15 and the communication opening 15 adjacent to that communication opening 15 in the third direction D3. In other words, the detection wiring 303 is arranged to surround the peripheries of multiple communication openings 15.

[0067] Both ends of the detection wiring 303 are connected to separate electrode pads, and a measuring unit 82 capable of measuring the resistance of the detection wiring 303 is connected to the detection wiring 303 via the electrode pads.

[0068] The reference resistance value is the resistance value measured through the electrode pad when the detection wiring 303 is not in contact with ink. When ink has not penetrated into the element substrate 8 and the detection wiring 303 is not in contact with ink, the value acquired by the measurement unit 82 is the reference resistance value.

[0069] On the other hand, when ink comes into contact with the detection wiring 303, the detection wiring 303 dissolves and the cross-sectional area of ​​the conductive portion decreases, causing the resistance value acquired by the measurement unit 82 to increase above the reference resistance value. Therefore, according to the configuration of the second embodiment, the resistance value of the detection wiring 303 is continuously measured, and if the resistance value increases, it can be determined that ink has infiltrated into the element substrate 8.

[0070] The material of the detection wiring 303 is selected from materials that are relatively susceptible to corrosion by ink. To detect ink penetration early, it is better to select a material that is more soluble. Specifically, metal materials that dissolve when they come into contact with ink, such as aluminum, tungsten, and zinc, can be used.

[0071] If the dissolution rate of the detection wiring 303 is slow, the timing of detection may be delayed. Therefore, in order to increase the dissolution rate upon contact with ink, a positive potential may be constantly applied to the detection wiring 303 itself to actively cause anodic dissolution.

[0072] Furthermore, in the second embodiment, both ends of the detection wiring 303 are connected to electrode pads, but in addition, the detection wiring 303 may be connected to an electrode pad at a location along the line so that the resistance value can be measured for each predetermined range. In this way, by configuring the resistance value for each predetermined range to be measured, the location where ink has entered can be identified. Then, ejection at the ink entry location is stopped, and the ejection signal is changed so that the ink is compensated for by another block, allowing printing to continue.

[0073] Next, a verification example will be described in which a liquid ejection head 42 was actually manufactured for each of the above-described embodiments, an evaluation test was carried out on the liquid ejection head 42, and the effects were verified.

[0074] <First verification example> First, as a first verification example, the first detection wiring 301 and the second detection wiring 302 of the first embodiment were formed using Au to a thickness of 2 μm and patterned. The first detection wiring 301 and the second detection wiring 302 were formed on the protective layer 114. As shown in FIG. 5, the first detection wiring 301 and the second detection wiring 302 were routed so as to surround all of the communication ports 15 while maintaining a parallel state. The distance between the first detection wiring 301 and the second detection wiring 302 was 5 μm. The ends of each wiring were connected to electrode pads, allowing the resistance between the first detection wiring 301 and the second detection wiring 302 to be measured by the measuring unit 82. Then, by forming other necessary terminals, etc., the liquid ejection head 42 of Example 1 was fabricated.

[0075] (Print durability evaluation test) The following describes a printing durability evaluation test performed on the liquid ejection head 42 according to the first verification example. First, the switch 83 was closed, and the resistance value between the first detection wiring 301 and the second detection wiring 302 was measured by the measuring unit 82. It was confirmed that the resistance value was the reference resistance value and that the wiring was open.

[0076] Thereafter, the liquid ejection head 42 was made to perform an ejection operation (1×10^12) times. A water-based magenta ink was used. During the ejection operation, the temperature of the liquid ejection head 42 was adjusted to 30°C. After the ejection operation, the switch 83 was closed, and the resistance value between the first detection wiring 301 and the second detection wiring 302 was measured by the measuring unit 82. As a result, it was confirmed that the obtained resistance value was the reference resistance value and that the wiring was open.

[0077] After that, the discharge operation was performed (1 x 10^12) times and the resistance value was measured repeatedly. When the resistance value was measured after the cumulative discharge operation (5 x 10^12) was completed, it was 10 MΩ at 5 V, indicating continuity.

[0078] When liquid ejection head substrate 1 of liquid ejection head 42 in this state was observed with an IR microscope, it was found that ink had entered through some of communication holes 15, filling the space between first detection wiring 301 and second detection wiring 302. When a printing evaluation was performed using liquid ejection head 42 in this state, no problems were found in the printing quality.

[0079] After that, an additional (1 x 10^12) ejection operation was performed and the resistance value was measured, which showed that the resistance value had further decreased to 5 kΩ at 5 V. When a print evaluation was performed using the liquid ejection head 42 in this state, faintness was observed in some of the print, resulting in a decrease in print quality.

[0080] When the liquid ejection head substrate 1 of the liquid ejection head 42 in this state was observed with an IR microscope, it was found that the ink had reached the drive wiring section beyond the first detection wiring 301 and the second detection wiring 302, and that part of the drive wiring had been damaged. After that, the flow path forming substrate 6 was peeled off from the element substrate 8, and the surface of the element substrate 8 was observed in more detail with an optical microscope, and it was found that the vibration plate 7 was cracked around the communication port 15.

[0081] Therefore, according to the configuration of the first verification example, when the measuring unit 82 measures a resistance value of 10 MΩ, it is possible to detect that ink has entered the element substrate 8 and replace the liquid ejection head 42 before a deterioration in print quality occurs, thereby preventing the creation of useless products with reduced print quality.

[0082] <Second verification example> Next, as a second verification example, the detection wiring 303 of the second embodiment was formed with AlCu to a thickness of 600 μm and patterned. 8, the detection wiring 303 was routed so as to surround all of the communication ports 15. Both ends of the detection wiring 303 were connected to electrode pads, and the resistance value thereof could be measured by the measuring unit 82. Then, by forming other necessary terminals, etc., the liquid ejection head 42 was produced.

[0083] (Printing evaluation test) A printing durability evaluation test conducted on the liquid ejection head 42 according to the second verification example will now be described. First, the switch 83 was closed, and the resistance of the detection wiring 303 was measured by the measurement unit 82. The initial measurement value plus the measurement tolerance was taken as the upper limit Rt of the reference resistance value.

[0084] Thereafter, the liquid ejection head 42 was made to perform an ejection operation (1 x 10^12) times. A water-based primer ink was used as the ink. During the ejection operation, the temperature of the liquid ejection head 42 was adjusted to 30°C. After the ejection operation, the switch 83 was closed, and the resistance of the circuit including the detection wiring 303 was measured by the measuring unit 82. As a result, it was confirmed that the obtained resistance value was equal to or less than the upper limit value Rt.

[0085] After that, the discharge operation was performed (1 x 10^12) times and the resistance value was measured repeatedly and alternately.When the resistance value was measured after the cumulative discharge operation (4 x 10^12) was completed, the resistance value was 1.3 times the upper limit value Rt.

[0086] When the liquid ejection head substrate 1 of the liquid ejection head 42 in this state was observed with an IR microscope, it was found that ink had entered through some of the communication holes 15 and had corroded the detection wiring 303. When a print evaluation was performed on the head in this state, no problems were found in the print quality.

[0087] After that, an additional (1 x 10^12) ejection operation was performed and the resistance value was measured, and the resistance value further increased to five times the upper limit value Rt. When a print evaluation was performed using the liquid ejection head 42 in this state, faintness was observed in some parts of the print, resulting in a decrease in print quality.

[0088] When the liquid ejection head substrate 1 of the liquid ejection head 42 in this state was observed with an IR microscope, it was found that the ink had reached the drive wiring portion beyond the detection wiring 303, and that part of the drive wiring had been damaged. After that, when it was observed in more detail, it was found that the bottom surface of the flow path forming substrate 6 had oxidized, and that lifting had occurred at the interface with the element substrate 8.

[0089] Therefore, according to the configuration of the second verification example, when the measuring unit 82 measures a resistance value five times the upper limit value Rt, it is possible to detect that ink has entered the element substrate 8 and replace the liquid ejection head 42 before a deterioration in print quality occurs due to ejection defects. This in turn makes it possible to prevent the creation of useless products with reduced print quality.

[0090] The disclosure of this embodiment includes the following configuration. (Configuration 1) a discharge port through which the liquid is discharged; a first substrate having a liquid chamber communicating with the ejection port, the liquid chamber having a communication port through which liquid supplied to the liquid chamber passes, and an energy generating element that generates energy for ejecting the liquid in the liquid chamber from the ejection port, the energy generating element being arranged at a position overlapping the ejection port when viewed in a first direction; a second substrate having a flow path communicating with the communication port of the liquid chamber and bonded to the first substrate; a detection wiring provided between the energy generating element and the communication port in a second direction intersecting the first direction, for detecting the intrusion of a liquid; A liquid ejection head comprising: (Configuration 2) 2. The liquid ejection head according to configuration 1, wherein the detection wiring is arranged to surround the periphery of the communication port except for a portion thereof when viewed in the first direction. (Configuration 3) A liquid ejection head according to configuration 2, wherein a gap portion of the communication port that is not surrounded by the detection wiring is arranged on the opposite side of the communication port from the energy generating element in the second direction. (Configuration 4) A liquid ejection head described in any one of configurations 1 to 3, further comprising, when the detection wiring is a first detection wiring, a second detection wiring that is arranged parallel to the first detection wiring in the second direction at least between the energy generating element and the communication port and is electrically insulated from the first detection wiring. (Configuration 5) 5. The liquid ejection head according to any one of configurations 1 to 4, further comprising: a plurality of the energy generating elements; and the detection wirings corresponding to the plurality of the energy generating elements. (Configuration 6) Further, a driving wiring connected to the energy generating element is provided, 6. The liquid ejection head according to any one of configurations 1 to 5, wherein the detection wiring is arranged between the drive wiring and the communication port in the second direction. (Configuration 7) 7. The liquid ejection head according to any one of configurations 1 to 6, wherein the detection wiring is disposed on the outermost surface of the first substrate. (Configuration 8) the first substrate has an insulating layer covering the energy generating element and a protective layer covering the insulating layer, 7. The liquid ejection head according to any one of configurations 1 to 6, wherein the detection wiring is formed between the insulating layer and the protective layer. (Configuration 9) the first substrate has a diaphragm on which the energy generating element is disposed and an insulating layer that covers the energy generating element, 7. The liquid ejection head according to any one of configurations 1 to 6, wherein the detection wiring is formed between the vibration plate and the insulating layer. (Configuration 10) the first substrate is provided with a plurality of the energy generating elements and a plurality of the communication ports aligned in a third direction intersecting the first direction and the second direction, 10. The liquid ejection head according to any one of configurations 1 to 9, wherein the detection wiring is arranged between the plurality of energy generating elements and the plurality of communication ports in the second direction. (Configuration 11) 11. The liquid ejection head according to any one of configurations 1 to 10, wherein an outer edge of the communication port is bonded to the first substrate. (Configuration 12) 12. The liquid ejection head according to any one of configurations 1 to 11, further comprising a third substrate joined to the first substrate, the third substrate having a plurality of the ejection ports formed therein. (Configuration 13) the energy generating element has a rectangular shape when viewed in the first direction, 13. The liquid ejection head according to any one of configurations 1 to 12, wherein the second direction is parallel to the longitudinal direction of the energy generating elements. (Configuration 14) The energy generating element is a piezoelectric element disposed on the outermost surface of the first substrate. 14. The liquid ejection head according to any one of claims 1 to 13. (Configuration 15) a discharge port through which the liquid is discharged; a first substrate having a liquid chamber communicating with the ejection port, the liquid chamber having a communication port through which liquid supplied to the liquid chamber passes, and an energy generating element that generates energy for ejecting the liquid in the liquid chamber from the ejection port, the energy generating element being arranged at a position overlapping the ejection port when viewed in a first direction; a second substrate having a flow path communicating with the communication port of the liquid chamber and bonded to the first substrate; a detection wiring provided at least between the energy generating element and the communication port in a second direction intersecting the first direction, for detecting the intrusion of a liquid; a measurement unit that measures a resistance value of a circuit including the detection wiring; A liquid ejection device comprising: (Configuration 16) When the detection wiring is a first detection wiring, the device further includes a second detection wiring that is arranged alongside the first detection wiring in the second direction at least between the energy generating element and the communication port and is electrically insulated from the first detection wiring, the material of the detection wiring is a corrosion-resistant metal material that does not dissolve even when it comes into contact with ink, 16. The liquid ejection device according to configuration 15, wherein the measurement unit measures a resistance value between the first detection wiring and the second detection wiring. (Configuration 17) the sensing wiring is made of a metal material that corrodes when it comes into contact with ink, 16. The liquid ejection device according to configuration 15, wherein the measurement unit measures a resistance value of the detection wiring. [Explanation of symbols]

[0091] 4...discharge port, 6...flow path forming substrate (second substrate), 8...element substrate (first substrate), 10...individual flow path (flow path), 11...pressure chamber (liquid chamber), 13...piezoelectric element (energy generating element), 15...communication port, 82...measuring unit, 301...first detection wiring (detection wiring), 302...second detection wiring (detection wiring), 500...liquid discharge device

Claims

1. a discharge port through which the liquid is discharged; a first substrate having a liquid chamber communicating with the ejection port, the liquid chamber having a communication port through which liquid supplied to the liquid chamber passes, and an energy generating element that generates energy for ejecting the liquid in the liquid chamber from the ejection port, the energy generating element being arranged at a position overlapping the ejection port when viewed in a first direction; a second substrate having a flow path communicating with the communication port of the liquid chamber and bonded to the first substrate; a detection wiring provided between the energy generating element and the communication port in a second direction intersecting the first direction, the detection wiring configured to detect the intrusion of a liquid; A liquid ejection head comprising:

2. The liquid ejection head according to claim 1 , wherein the detection wiring is arranged so as to surround the periphery of the communication port except for a portion thereof when viewed in the first direction.

3. The liquid ejection head according to claim 2 , wherein a gap portion of the communication port that is not surrounded by the detection wiring is disposed on the opposite side of the communication port from the energy generating element in the second direction.

4. A liquid ejection head as described in claim 1, further comprising a second detection wiring, when the detection wiring is a first detection wiring, arranged parallel to the first detection wiring in the second direction at least between the energy generating element and the communication port, and electrically insulated from the first detection wiring.

5. The liquid ejection head according to claim 1 , further comprising a plurality of the energy generating elements, and the detection wirings corresponding to the plurality of the energy generating elements.

6. Further, a driving wiring connected to the energy generating element is provided, The liquid ejection head according to claim 1 , wherein the detection wiring is disposed between the drive wiring and the communication port in the second direction.

7. The liquid ejection head according to claim 1 , wherein the detection wiring is disposed on the outermost surface of the first substrate.

8. the first substrate has an insulating layer covering the energy generating element and a protective layer covering the insulating layer, The liquid ejection head according to claim 1 , wherein the detection wiring is formed between the insulating layer and the protective layer.

9. the first substrate has a diaphragm on which the energy generating element is disposed and an insulating layer that covers the energy generating element; The liquid ejection head according to claim 1 , wherein the detection wiring is formed between the vibration plate and the insulating layer.

10. the first substrate is provided with a plurality of the energy generating elements and a plurality of the communication ports aligned in a third direction intersecting the first direction and the second direction, The liquid ejection head according to claim 1 , wherein the detection wiring is arranged between the plurality of energy generating elements and the plurality of communication ports in the second direction.

11. The liquid ejection head according to claim 1 , wherein an outer edge of the communication port is bonded to the first substrate.

12. The liquid ejection head according to claim 1 , further comprising a third substrate bonded to the first substrate and having a plurality of the ejection ports formed therein.

13. the energy generating element has a rectangular shape when viewed in the first direction, The liquid ejection head according to claim 1 , wherein the second direction is parallel to the longitudinal direction of the energy generating elements.

14. 14. The liquid ejection head according to claim 1, wherein the energy generating element is a piezoelectric element disposed on the outermost surface of the first substrate.

15. a discharge port through which the liquid is discharged; a first substrate having a liquid chamber communicating with the ejection port, the liquid chamber having a communication port through which liquid supplied to the liquid chamber passes, and an energy generating element that generates energy for ejecting the liquid in the liquid chamber from the ejection port, the energy generating element being arranged at a position overlapping the ejection port when viewed in a first direction; a second substrate having a flow path communicating with the communication port of the liquid chamber and bonded to the first substrate; a detection wiring provided at least between the energy generating element and the communication port in a second direction intersecting the first direction, for detecting the intrusion of a liquid; a measurement unit that measures a resistance value of a circuit including the detection wiring; A liquid ejection device comprising:

16. When the detection wiring is a first detection wiring, the device further includes a second detection wiring that is arranged alongside the first detection wiring in the second direction at least between the energy generating element and the communication port and is electrically insulated from the first detection wiring, the material of the detection wiring is a corrosion-resistant metal material that does not dissolve even when it comes into contact with ink, The liquid ejection device according to claim 15 , wherein the measurement unit measures a resistance value between the first detection wiring and the second detection wiring.

17. the sensing wiring is made of a metal material that corrodes when it comes into contact with ink, The liquid ejection device according to claim 15 , wherein the measurement unit measures the resistance value of the detection wiring.

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