JP2008221652A - Method for inspecting liquid jet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for inspecting a liquid jet head capable of identifying an occurrence position of a malfunction and specifying the cause thereof. <P>SOLUTION: When a piezoelectric element 300 is formed on a fluid channel forming substrate 10, a first independent electrode layer 100A which is electrically independent from a lower electrode film 60 and the upper electrode film 80 of the piezoelectric element is formed beforehand on a diaphragm at least at the periphery of an opening section. In the condition that first and second liquid channels of the liquid jet head are filled with a conductive liquid, the conductivity inspection process of inspecting the conductive condition between the conductive liquid and each of the lower electrode film of the piezoelectric element and the first independent electrode layer, is carried out. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for inspecting a liquid ejecting head that ejects droplets from nozzles, and more particularly, to a method for inspecting an ink jet recording head that ejects ink droplets.

  As a typical example of the liquid ejecting head, for example, it has a plurality of pressure generation chambers communicating with nozzle openings for ejecting ink droplets and a reservoir communicating with the plurality of pressure generation chambers, and is supplied from the reservoir to the pressure generation chamber An ink jet recording head in which the applied ink is pressurized by a piezoelectric element and ejected from a nozzle opening is exemplified. Specifically, a flow path formed with a plurality of pressure generation chambers, an ink supply path that communicates with each of the plurality of pressure generation chambers, and a communication portion that communicates with each pressure generation chamber via the ink supply path. A substrate, a piezoelectric element formed on one side of the flow path forming substrate, and a sealing substrate (bonding substrate) having a piezoelectric element holding portion bonded to the flow path forming substrate and protecting the piezoelectric element. In some cases, a reservoir portion that constitutes a reservoir together with the communication portion is provided so as to penetrate the sealing substrate (see, for example, Patent Document 1).

  In such an ink jet recording head, in the manufacturing process, a conductive liquid, for example, ink is filled from the reservoir to the pressure generating chamber, and the gap between the lower electrode film constituting the piezoelectric element and the conductive liquid is filled. An inspection process for detecting the continuity state is performed. That is, in this inspection process, it is inspected for the leakage of the conductive liquid. And in this inspection process, what is in a conductive state is determined to be a defective product in which the diaphragm is cracked and discarded, and what is in an insulating state is determined to be a non-defective product.

JP 2004-262225 A

  However, the leakage of the conductive liquid is not only due to the crack of the diaphragm in the region where the lower electrode film is formed, but also due to the crack of the diaphragm in the region where the lower electrode film is not formed, There is a leakage from the reservoir due to a defect in the adhesive bonding the substrates, and it is not possible to reliably detect these defects only by detecting the conduction state between the lower electrode film and the conductive liquid. There is. Moreover, even if the lower electrode film is formed on the entire surface of the flow path forming substrate, it is possible to specify the position where the defect occurs and the cause thereof only by determining the conduction state between the lower electrode film and the conductive liquid. There is a problem that it is impossible to take appropriate measures against the occurrence of defects.

  Such a problem exists not only in an ink jet recording head but also in a liquid ejecting head that ejects liquid other than ink.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a liquid ejecting head inspection method capable of specifying the occurrence position of a defect and the cause thereof.

The present invention that solves the above-described problems includes a flow path forming substrate having a first liquid flow path including a pressure generation chamber that communicates with a nozzle that discharges droplets, and a diaphragm on one surface side of the flow path forming substrate. A piezoelectric element composed of a lower electrode film, a piezoelectric layer, and an upper electrode film provided through an opening, and an opening provided in the diaphragm and bonded to one surface side of the flow path forming substrate by the adhesive. A method for inspecting a liquid jet head having a bonding substrate having a second liquid channel communicating with one liquid channel, wherein the piezoelectric element is formed when the piezoelectric element is formed on the channel forming substrate. A first independent electrode layer that is electrically independent of the lower electrode film and the upper electrode film is formed on at least a peripheral portion of the opening on the diaphragm, and the first of the liquid jet head is formed. And in the state where the second liquid channel is filled with the conductive liquid, A method for inspecting a liquid ejecting head, comprising conducting a continuity inspection step of detecting a continuity state between a lower electrode film of a piezoelectric element, the first independent electrode layer, and the conductive liquid. .
In the present invention, the occurrence position and the cause of the defect in the continuity inspection process, specifically, whether the vibration plate is cracked or the adhesion failure of the adhesive bonding the bonded substrate is easily and accurately specified. be able to. Therefore, it is possible to take appropriate measures against the occurrence of defects.

  Here, the liquid ejecting head includes a nozzle forming member made of a conductive material and bonded to the other surface side of the flow path forming substrate. In the continuity inspection step, the lower electrode film and It is preferable to detect a conduction state between the first independent electrode layer and the nozzle forming member. Thereby, the conduction state between the lower electrode film and the independent electrode layer and the conductive liquid can be detected relatively easily.

  When forming the piezoelectric element on the flow path forming substrate, a second independent electrode layer that is electrically independent from the lower electrode film, the upper electrode film, and the first independent electrode layer, It is further provided in a region facing the first liquid flow path between the first independent electrode layer and the lower electrode film, and in the conduction detection step, the second independent electrode layer and the conductive liquid are provided. It is preferable to further detect a conduction state between the two. As a result, it is possible to more accurately identify the occurrence position of the defect and the cause thereof.

  Furthermore, it is preferable to form the width of the portion along the opening of the first independent electrode layer as thin as possible. As a result, it is possible to more accurately identify the occurrence position of the defect and the cause thereof.

Hereinafter, the present invention will be described in detail based on an embodiment.
FIG. 1 is an exploded perspective view showing an outline of an ink jet recording head according to an embodiment of the present invention, FIG. 2 is a plan view and a sectional view taken along line AA ′ of FIG. 1, and FIG. It is a top view which shows the pattern of an electrode film and an independent electrode layer.

  As shown in the drawing, a flow path forming substrate 10 constituting an ink jet recording head, which is an example of a liquid ejecting head, is composed of a silicon single crystal substrate having a plane orientation (110) in this embodiment, and one surface thereof is made of carbon dioxide. An elastic film 50 made of silicon is formed, and a first ink flow path including the pressure generating chamber 12 is formed. First, the flow path forming substrate 10 is provided with two rows in which a plurality of pressure generating chambers 12 partitioned by the partition wall 11 are arranged in parallel along the width direction. In addition, an ink supply path 13 and a communication path 14 that are partitioned by partition walls 11 and communicated with the pressure generation chambers 12 are provided outside the row of the pressure generation chambers 12 of the flow path forming substrate 10. Furthermore, a communication portion 15 that communicates with each communication path 14 is provided outside the communication path 14. The communication portion 15 communicates with a reservoir portion of a protective substrate, which will be described later, and constitutes a part of a reservoir common to the pressure generation chambers 12 in each row.

  The ink supply path 13 is formed so as to have a narrower cross-sectional area than the pressure generation chamber 12, and maintains a constant flow path resistance of ink flowing into the pressure generation chamber 12 from the communication portion 15. For example, in the present embodiment, the ink supply path 13 is formed with a width smaller than the width of the pressure generating chamber 12 by narrowing the width of the flow path from one side. Each communication path 14 is formed by extending the partition walls 11 on both sides in the width direction of the pressure generating chamber 12 to the communication part 15 side to partition the space between the ink supply path 13 and the communication part 15.

  In this embodiment, the ink supply path is formed by narrowing the width of the flow path from one side. However, the ink supply path may be formed by narrowing the width of the flow path from both sides.

  As a material for the flow path forming substrate 10, a silicon single crystal substrate is used in the present embodiment. However, the material is not limited to this, and glass ceramics, stainless steel, etc. may be used.

  A nozzle plate (a kind of nozzle forming member) in which a nozzle opening 21 communicating with the vicinity of the end of each pressure generating chamber 12 on the side opposite to the ink supply path 13 is formed on the opening surface side of the flow path forming substrate 10. 20 is fixed through an adhesive, a heat welding film, or the like. Examples of the material of the nozzle plate 20 include glass ceramics, a silicon single crystal substrate, and stainless steel (SUS). In the present embodiment, stainless steel is used.

  On the other hand, the elastic film 50 is formed on the side opposite to the opening surface of the flow path forming substrate 10 as described above, and the insulator film 51 is formed on the elastic film 50. Furthermore, a piezoelectric element 300 including a lower electrode film 60, a piezoelectric layer 70, and an upper electrode film 80 is formed on the insulator film 51. In general, one of the electrodes of the piezoelectric element 300 is used as a common electrode, and the other electrode is patterned together with the piezoelectric layer 70 for each pressure generating chamber 12 to form individual electrodes. In the present embodiment, the lower electrode film 60 is used as a common electrode of the piezoelectric element 300 and the upper electrode film 80 is used as an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for convenience of a drive circuit and wiring. In the above-described example, the elastic film 50, the insulator film 51, and the lower electrode film 60 substantially function as a diaphragm, but only the elastic film 50 and the insulator film 51 may function as a diaphragm. Alternatively, only the lower electrode film 60 may function as a diaphragm without providing the elastic film 50 and the insulator film 51.

  On the flow path forming substrate 10, a protective substrate 30, which is a bonding substrate having a piezoelectric element holding portion 31 for protecting the piezoelectric element 300, is bonded by an adhesive 35. In the present embodiment, the piezoelectric element holding portion 31 is provided for each row of the pressure generating chambers 12. In addition, although these piezoelectric element holding | maintenance parts 31 may be sealed, they do not need to be sealed. In addition, on the outside of each piezoelectric element holding portion 31 of the protective substrate 30, a reservoir portion 32 that is a second ink flow path is formed. Each of these reservoir sections 32 communicates with each communication section 15 of the flow path forming substrate 10 through an opening 55 provided through the elastic film 50 and the insulator film 51, and each pressure generation chamber for each column. 12 constitutes a common reservoir 150. Further, a connection hole 33 that penetrates the protective substrate 30 in the thickness direction is provided between the piezoelectric element holding portions 31 of the protective substrate 30, that is, in the central portion of the protective substrate 30.

  On the protective substrate 30, a compliance substrate 40 including a sealing film 41 made of a material having low rigidity and flexibility and a fixing plate 42 made of a hard material such as metal is joined. A region of the fixing plate 42 facing the reservoir 150 is an opening 43 that is completely removed in the thickness direction, and one surface of the reservoir 150 is sealed only by the sealing film 41.

  Here, lead electrodes 90 made of, for example, gold (Au) are connected to the upper electrode film 80 which is an individual electrode of each piezoelectric element 300. The lead electrode 90 is drawn from the vicinity of the end of each piezoelectric element 300 opposite to the ink supply path 13 in the longitudinal direction, and extends on the insulator film 51 to the vicinity of the center of the flow path forming substrate 10. ing. That is, the lead electrode 90 extends from the inside of the piezoelectric element holding portion 31 to a region facing the connection hole 33. In addition, the lower electrode film 60 that is a common electrode of the piezoelectric element 300 is continuously extended in a region facing the pressure generation chambers 12 in the parallel direction of the pressure generation chambers 12. The lower electrode film 60 extends outside the row of the pressure generation chambers 12 to a region facing the connection hole 33 provided in the protective substrate 30, similarly to the lead electrode 90. The lead electrode 90 and the lower electrode film 60 extended in this way are mounted on the protective substrate 30 by a connection wiring made of a bonding wire extended in the connection hole 33, although not shown. Connected to the driving IC.

  The independent electrode layer 100 (first independent electrode layer 100A) independent of the upper electrode film 80 and the lower electrode film 60 of the piezoelectric element 300 is formed on the insulator film 51 in the region outside the row of the pressure generating chambers 12. , A second independent electrode layer 100B) is provided (see FIG. 3). The independent electrode layer 100 is basically provided in a bonding region to which the protective substrate 30 is bonded, and is covered with an adhesive 35. In addition, being independent of the upper electrode film 80 and the lower electrode film 60 of the piezoelectric element 300 means a state in which the upper electrode film 80 and the lower electrode film 60 and the independent electrode layer 100 are not electrically connected. . Of course, the independent electrode layer 100 is provided independently of the lead electrode 90 drawn from the upper electrode film 80.

  More specifically, the elastic film 50 and the insulator film 51 in the region facing the communication portion 15 of the flow path forming substrate 10 are arranged on the peripheral portion of the opening 55 that allows the communication portion 15 and the reservoir portion 32 to communicate with each other. The independent electrode layer 100A is provided. The first independent electrode layer 100 </ b> A is provided close to the end face of the opening 55, but is provided so that the end face of the first independent electrode layer 100 </ b> A does not coincide with the end face of the opening 55.

  On the insulator film 51 in the region facing the ink supply path 13 and the communication path 14, that is, on the insulator film 51 in the region between the first independent electrode layer 100A and the lower electrode film 60, the second An independent electrode layer 100B is further provided. The second independent electrode layer 100B is electrically independent of the lower electrode film 60 and the upper electrode film 80, and is also electrically independent of the first independent electrode layer 100A.

  The first and second independent electrode layers 100A and 100B are covered with the adhesive 35 as described above, but the protective substrate 30 is formed in a region outside the row of the pressure generating chambers 12 like the lower electrode film 60. The front end portion is exposed to the inside of the connection hole 33.

  Further, in the present embodiment, the first and second independent electrode layers 100A and 100B are made of the same layer as the lower electrode film 60, and are formed at the same time when the lower electrode film 60 is patterned. The first and second independent electrode layers 100A and 100B are not necessarily formed of the same layer as the lower electrode film 60. For example, the first and second independent electrode layers 100A and 100B may be formed of the same layer as the lead electrode 90. The lower electrode film 60 and the lead electrode 90 may be provided separately.

  Such an ink jet recording head of this embodiment takes in ink from an external ink supply means (not shown), fills the interior from the reservoir 150 to the nozzle opening 21, and then follows a recording signal from a drive circuit (not shown). The piezoelectric film 300 is driven by applying a voltage between the lower electrode film 60 and the upper electrode film 80 corresponding to the pressure generation chamber 12 via the external wiring, thereby forming the elastic film 50 constituting the diaphragm. In addition, by bending and deforming the insulator film 51, the pressure in each pressure generation chamber 12 is increased, and ink droplets are ejected from the nozzle openings 21.

  Hereinafter, for an example of the manufacturing method and the inspection method of the ink jet recording head according to this embodiment, refer to cross-sectional views showing a part in the longitudinal direction of the pressure generating chamber 12 of the flow path forming substrate of FIGS. To explain. 4 to 6 are diagrams showing a manufacturing process of the recording head, and FIG. 7 is a diagram showing a continuity inspection process of the recording head.

  First, as shown in FIG. 4A, a silicon dioxide film 52 that constitutes an elastic film 50 is formed on the surface of a flow path forming substrate wafer 110 that is a silicon wafer and in which a plurality of flow path forming substrates 10 are integrally formed. Form. Next, as shown in FIG. 4B, an insulator film 51 made of an oxide film made of a material different from that of the elastic film 50 is formed on the elastic film 50.

  Next, as shown in FIG. 4C, a first metal film 160 is formed on the entire surface of the insulator film 51, and the first metal film 160 is patterned to form the lower electrode film 60, the first Then, the second independent electrode layers 100A and 100B are formed. Next, as shown in FIG. 3D, for example, a piezoelectric material layer 170 made of lead zirconate titanate (PZT) or the like and a second metal film 180 are formed on the entire surface of the flow path forming substrate wafer 110. Then, the piezoelectric material layer 170 and the second metal film 180 are patterned in a region facing each pressure generating chamber 12 to form the piezoelectric element 300 including the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80. Form.

  Next, as shown in FIG. 4E, a third metal film 190 is formed over the entire surface of the flow path forming substrate wafer 110, and this metal film 190 is patterned for each piezoelectric element 300. Thus, the lead electrode 90 is formed.

  Next, a protective substrate wafer 130 made of a silicon wafer on which a plurality of protective substrates 30 are integrally formed, as shown in FIG. Bonded with an epoxy adhesive.

  Next, as shown in FIG. 5 (b), after the flow path forming substrate wafer 110 is thinned to a certain thickness, as shown in FIG. 6 (a), on the flow path forming substrate wafer 110, for example, A protective film 53 is newly formed and patterned into a predetermined shape. Then, as shown in FIG. 6B, the flow path forming substrate wafer 110 is anisotropically etched (wet etching) using the protective film 53 as a mask, and the pressure generating chamber 12 is applied to the flow path forming substrate wafer 110. The ink supply path 13, the communication path 14, and the communication part 15 are formed. That is, the flow path forming substrate wafer 110 is etched by using an etchant such as an aqueous potassium hydroxide (KOH) solution until the elastic film 50 is exposed. Etc. are formed simultaneously. Further, the elastic film 50 and the insulator film 51 are removed to form an opening 55, and the communication part 15 and the reservoir part 32 are communicated.

  Thereafter, unnecessary portions of the outer peripheral edge portions of the flow path forming substrate wafer 110 and the protective substrate wafer 130 are removed by cutting, for example, by dicing. The nozzle plate 20 having the nozzle openings 21 is bonded to the surface of the flow path forming substrate wafer 110 opposite to the protective substrate wafer 130, and the compliance substrate 40 is bonded to the protective substrate wafer 130. To do. Then, the flow path forming substrate wafer 110, the protective substrate wafer 130 and the like are divided into one chip size flow path forming substrate 10 and the like (see FIG. 2).

  In this state, a continuity inspection process is performed next. Specifically, as shown in FIG. 7, the ink flow path, that is, the reservoir 150 to the pressure generating chamber 12 is filled with a conductive liquid, for example, ink, and in this state, the lower electrode film 60 and the first independent electrode are filled. The conductive state between the layer 100A and the second independent electrode layer 100B and the conductive liquid is detected. In the present embodiment, since the nozzle plate 20 is made of a conductive material, a conductive state is established between the lower electrode film 60, the first and second independent electrode layers 100A and 100B, and the nozzle plate 20. It was made to detect. The detection method of the conduction state is not particularly limited. For example, a predetermined probe pin 200 is connected to the lower electrode film 60 exposed in the connection hole 33, the first and second independent electrode layers 100A and 100B, and the nozzle plate 20. And the resistance value between the probe pins 200 may be measured. Based on the measurement result, whether the lower electrode film 60 exposed in the connection hole 33, the first and second independent electrode layers 100A and 100B, and the nozzle plate 20 are in a conductive state or an insulating state is determined. Only the ink jet recording head that has been determined and determined to be in an insulated state is regarded as a non-defective product, that is, a product.

  As described above, in the present embodiment, when the ink jet recording head is manufactured, the independent electrode layer 100 (first and second independent electrode layers 100A and 100B) independent of the lower electrode film 60 constituting the piezoelectric element 300 is used. And a conduction state between the lower electrode film 60 and the independent electrode layer 100 and the nozzle plate 20 is detected in the conduction inspection step. Thereby, for example, it is possible to easily and reliably detect a manufacturing failure due to a crack in the elastic film 50 and the insulator film 51 constituting the diaphragm, an adhesion failure of the adhesive 35, or the like. If the elastic film 50 and the insulator film 51 are cracked or if the adhesive 35 is poorly bonded, the ink leaks and the lower electrode film 60, the first and second independent electrode layers 100A and 100B, The nozzle plate 20 is in a conductive state. For this reason, by performing the continuity inspection process, the occurrence of such a defect can be detected easily and reliably, and the occurrence of an initial defect during user use can be greatly reduced.

  Further, by detecting the conduction state between the independent electrode layer 100 and the nozzle plate 20 as well as the conduction state between the lower electrode film 60 and the nozzle plate 20, it is possible to identify the position and cause of the failure. Specifically, the position of occurrence of a defect is determined to some extent depending on whether the nozzle plate 20 and the lower electrode film 60, the first independent electrode layer 100A, or the second independent electrode layer 100B are in a conductive state. Can be identified. Furthermore, if the lower electrode film 60 or the second independent electrode layer 100B and the nozzle plate 20 are in a conductive state, it can be determined that the diaphragm is cracked, while the first independent electrode layer 100A. And the nozzle plate 20 can be determined to be due to poor adhesion of the adhesive 35. In this way, by specifying the position and cause of the failure, it is possible to take appropriate measures against the failure that has occurred.

  From the viewpoint of specifying the cause of occurrence in this way, it is preferable to form the width of the portion along the opening 55 of the first independent electrode layer 100A as narrow as possible. In particular, the width W (see FIG. 2) of the first independent electrode layer 100A in the portion adjacent to the second independent electrode layer 100B, that is, the region facing the communication path 14, is made as thin as possible. Is preferred. Thereby, it is possible to more accurately determine whether the cause of the failure is a crack in the diaphragm or an adhesion failure.

(Other embodiments)
As mentioned above, although embodiment of this invention was described, of course, this invention is not limited to this embodiment. For example, in the above-described embodiment, the conduction state between the lower electrode film 60, the first and second independent electrode layers 100A and 100B, and the nozzle plate 20 is detected. The conductive state between the electrode film 60, the first and second independent electrode layers 100A and 100B, and the conductive liquid (ink) may be directly detected. In the above-described embodiment, the second independent electrode layer 100B is provided between the lower electrode film 60 and the first independent electrode layer 100A. However, the second independent electrode layer 100B is provided. The second independent electrode layer 100 </ b> B only needs to be electrically independent of the upper electrode film 80, and may be formed continuously from the lower electrode film 60.

  In the above-described embodiment, an ink jet recording head has been described as an example of a liquid ejecting head. However, the present invention is widely intended for all liquid ejecting heads and ejects liquids other than ink. Of course, the present invention can also be applied to the case of inspecting the liquid jet head. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like.

FIG. 2 is an exploded perspective view illustrating an outline of the recording head according to the first embodiment. 2A and 2B are a plan view and a cross-sectional view of the recording head according to the first embodiment. 3 is a plan view showing a lower electrode film and an independent electrode layer according to Embodiment 1. FIG. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. 5 is a cross-sectional view illustrating a manufacturing process of the recording head according to Embodiment 1. FIG. FIG. 3 is a cross-sectional view illustrating a continuity inspection process of the recording head according to the first embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Flow path formation board | substrate, 12 Pressure generation chamber, 13 Ink supply path, 14 Communication path, 15 Communication part, 20 Nozzle plate, 21 Nozzle opening, 30 Protection board, 31 Piezoelectric element holding part, 32 Reservoir part, 33 Connection hole, 35 adhesive, 40 compliance substrate, 50 elastic film, 51 insulator film, 55 opening, 60 lower electrode film, 70 piezoelectric layer, 80 upper electrode film, 90 lead electrode, 100 independent electrode layer, 300 piezoelectric element

Claims (4)

A flow path forming substrate having a first liquid flow path including a pressure generating chamber communicating with a nozzle for discharging droplets, a lower electrode film provided on one surface side of the flow path forming substrate via a vibration plate, and piezoelectric A piezoelectric element composed of a body layer and an upper electrode film, and a first element connected to the one surface side of the flow path forming substrate by an adhesive and communicated with the first liquid flow path through an opening provided in the diaphragm. An inspection method for a liquid jet head having a bonding substrate having two liquid flow paths,
When forming the piezoelectric element on the flow path forming substrate, at least the first independent electrode layer electrically independent from the lower electrode film and the upper electrode film of the piezoelectric element is provided on the diaphragm. Formed on the periphery of the opening,
Between the lower electrode film and the first independent electrode layer of the piezoelectric element and the conductive liquid in a state where the first and second liquid flow paths of the liquid jet head are filled with the conductive liquid. A method for inspecting a liquid ejecting head, comprising performing a continuity inspection step of detecting a continuity state in each. The liquid ejecting head includes a nozzle forming member made of a conductive material and joined to the other surface side of the flow path forming substrate.
2. The liquid ejecting head according to claim 1, wherein in the continuity inspection step, a continuity state between the lower electrode film and the first independent electrode layer and the nozzle forming member is detected. Inspection method. When forming the piezoelectric element on the flow path forming substrate, a second independent electrode layer that is electrically independent from the lower electrode film, the upper electrode film, and the first independent electrode layer, Further provided in a region facing the first liquid flow path between one independent electrode layer and the lower electrode film,
3. The liquid ejecting head according to claim 1, wherein in the conduction detecting step, a conduction state between the second independent electrode layer and the conductive liquid is further detected. Inspection method.   The method for inspecting a liquid jet head according to claim 3, wherein a width of a portion along the opening of the first independent electrode layer is formed as thin as possible.

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