JP2019006107A - Liquid discharge head and liquid discharge device - Google Patents

Abstract

To provide a liquid discharge head which can detect dissolution of a substrate caused by liquid, and can thereby suppress erroneous operation of the liquid discharge head.SOLUTION: A liquid discharge head has: a substrate 100 including an insulation film; an energy generation element 301 being arranged on the substrate 100, and generating energy which is used for discharging liquid; a flow passage 302 which is formed while penetrating the substrate 100, and communicates with a discharge port for discharging the liquid; and a wiring layer 303 which is formed on the insulation film of the substrate 100, and used for driving the energy generation element, being the wiring layer 303 which is arranged with an interval from a wall 304 forming the flow passage 302, and arranged while surrounding the flow passage 302 when viewing the substrate 100 in a plan view.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a liquid discharge head and a liquid discharge apparatus.

  2. Description of the Related Art Conventionally, as a liquid discharge method for a liquid discharge head, a thermal method is known in which bubbles are generated in a liquid by heat energy generated by a heating element, and the liquid is discharged using the bubbles. The thermal type liquid discharge head includes a substrate on which a heating element is provided, and a flow path forming member that is bonded to the substrate and includes a discharge port for discharging liquid. A flow path that communicates with the discharge port is formed between the substrate and the flow path forming member, and a supply path that penetrates the substrate and communicates with the flow path is formed on the substrate. The heating element is provided at a position corresponding to the discharge port of the substrate.

In a thermal-type liquid discharge head that discharges ink as a liquid, a protective film or an insulating film is generally provided at a contact point with ink for the purpose of protection and insulation from the ink. However, these protective films and insulating films may be dissolved by ink. For this reason, if a wiring or circuit protected by such a protective film or insulating film is exposed to come into contact with ink and a leakage current flows through the ink, the liquid discharge head may malfunction. Therefore, it is necessary to take measures to suppress malfunction of the liquid discharge head against dissolution of the protective film and insulating film by ink.
Patent Document 1 describes a configuration in which a plurality of wiring layers are formed in a ring shape so as to surround a supply path inside a substrate (interlayer insulating film). The plurality of wiring layers are stacked in the thickness direction of the substrate, and are electrically connected to each other and the substrate through interlayer vias. For this reason, even if some or all of the plurality of wiring layers are exposed to the supply path due to dissolution of the substrate (interlayer insulating film) and come into contact with the ink, and a leak path occurs between the ink and the ink, the current flowing into the wiring layer Will escape to the substrate (ground potential). As a result, it is possible to suppress the leakage current from flowing to other wirings and circuits, and to suppress the influence that the liquid discharge head causes a malfunction.

US Pat. No. 7,594,713

However, in the above-described configuration, the plurality of wiring layers are wiring layers that are electrically independent from the wiring for driving an energy generating element such as a heater, and normally no potential is applied to the wiring layers. For this reason, when the insulating film is dissolved, the current that flows from the ink to the substrate through the wiring layer is small, so that it is difficult to detect it, and therefore, it is difficult to detect the dissolution by the ink. For this reason, there is a possibility that the melting proceeds from between the interlayer vias and the wiring layer itself is melted. In this case, there is a possibility that the liquid discharge head malfunctions.
SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid discharge head and a liquid discharge apparatus that can detect dissolution of a substrate by a liquid and thereby prevent malfunction.

In order to achieve the above-described object, a liquid discharge head according to the present invention includes a substrate including an insulating film, an energy generating element that is provided on the substrate and generates energy used to discharge liquid, and penetrates the substrate. And a wiring layer formed in the insulating film of the substrate and used for driving the energy generating element, the wall forming the flow path. And a wiring layer disposed so as to surround the flow path when the substrate is viewed in plan view.
The liquid ejection apparatus of the present invention includes the above-described liquid ejection head and a leak detection mechanism that is electrically connected to the wiring layer and detects a leakage current flowing from the wiring layer.
According to such a liquid discharge head and a liquid discharge device, when the insulating film is dissolved by the liquid through the flow path, and the wiring layer is exposed to the flow path and contacts the liquid, the liquid ( Leakage current flows to (low potential). This leakage current can be easily detected by connecting a leakage detection mechanism to the wiring layer. For this reason, it is possible to stop the liquid discharge operation or replace the liquid discharge head when the leakage current is detected, and to prevent the liquid discharge head from causing a malfunction. .

As described above, according to the present invention, it is possible to detect the dissolution of the substrate by the liquid, and thereby to prevent malfunction of the liquid discharge head and the liquid discharge apparatus.

FIG. 3 is a plan view illustrating a configuration example of a liquid ejection head according to the first embodiment. 1 is a block diagram illustrating a circuit configuration example of a liquid ejection device according to a first embodiment. It is a top view which shows the wiring layout of the board | substrate concerning 1st Embodiment. It is sectional drawing which shows the structural example of the board | substrate which concerns on 1st Embodiment. It is sectional drawing which shows the structural example of the board | substrate which concerns on 2nd Embodiment. It is sectional drawing which shows the structural example of the board | substrate concerning 3rd Embodiment. It is sectional drawing which shows the structural example of the board | substrate concerning 3rd Embodiment. It is a schematic block diagram which shows an inkjet recording device. It is a perspective view which shows an inkjet recording head.

  Embodiments of the present invention will be described below with reference to the drawings. In this specification, a liquid discharge head that discharges ink and records an image on a recording medium will be described as an example of the liquid discharge head of the present invention. However, the present invention can also be applied to a liquid discharge head that discharges other liquids. It is. In addition, a thermal method is used in which a heating element is used as a recording element (energy generating element) and bubbles are generated to discharge a liquid. However, a recording element substrate employing a piezo method and other various liquid discharge methods is employed. The present invention can also be applied. The present invention can also be used as a recording element substrate of an industrial recording apparatus such as biochip fabrication, electronic circuit printing, and resist coating for forming a circuit pattern of a semiconductor wafer.

(First embodiment)
FIG. 1 is a plan view showing a configuration example of a liquid discharge head according to the first embodiment of the present invention. The liquid discharge head 10 includes a substrate 100 including a base material made of silicon, and a flow path forming member (not shown) having a plurality of discharge ports for discharging liquid is bonded to the substrate 100. Yes. A plurality of flow paths communicating with the plurality of discharge ports are formed between the substrate 100 and the flow path forming member, and a plurality of supply paths penetrating the substrate 100 and communicating with the plurality of flow paths are formed on the substrate 100. Is formed. On the surface of the substrate 100, a supply port array 101 including openings (supply ports) of a plurality of supply paths is formed. Between the two supply port arrays 101, a heater array 102 is formed in which a plurality of heating elements (heaters) as energy generating elements that generate energy used for discharging liquid are arranged. A drive element section 103 and a heater selection circuit section 104 are provided adjacent to the two supply port arrays 101 and the heater array 102. The drive element unit 103 and the heater selection circuit unit 104 are respectively composed of a plurality of drive elements and a plurality of heater selection circuits provided corresponding to the plurality of heaters. At the end of the substrate 100, a recording data supply circuit 105 and a pad row 106 for electrical connection with the outside are provided. The heater selection circuit unit 104 outputs a drive signal based on the print data from the print data supply circuit 105, and the drive element unit 103 prints the print data from the print data supply circuit 105 and the drive signal from the heater selection circuit unit 104. Based on the above, the corresponding heater is driven. Thereby, ink is ejected from the corresponding ejection port. The outer shape of the substrate 100 is not limited to the illustrated parallelogram, and may be a rectangle or other shapes.
The liquid discharge head 10 is supplied from the supply port to the heater by using one of the two supply port rows 101 provided on both sides of the heater row 102 as a collection port row for collecting liquid. An ink circulation configuration in which the ink is collected from the collection port may be employed.

FIG. 2 is a block diagram illustrating a circuit configuration example of a liquid ejection apparatus including the liquid ejection head according to the present embodiment.
The liquid ejection head 200 includes a plurality of heater units 203 each including a heater and a driving element that drives the heaters, a plurality of heater selection circuits 206 corresponding to the plurality of heater units 203, and a recording data supply circuit 207. Is provided. The plurality of heater sections 203 are connected to a heater power supply wiring 201 that supplies a power supply potential to the heater and a heater ground wiring 202 that supplies a reference potential to the heater. The plurality of heater selection circuits 206 are connected to a logic power supply wiring 204 that supplies a power supply potential to a logic circuit including the heater selection circuit 206 and a logic ground wiring 205 that supplies a reference potential to the logic circuit. The recording data supply circuit 207 is connected to the plurality of heater units 203 and the plurality of heater selection circuits 206.
In the main body 208 of the liquid ejection apparatus, the heater power supply wiring 201 is connected to the heater power supply 209 via the leak detection mechanism 210, and the logic power supply wiring 204 is connected to the logic power supply 211 via the leak detection mechanism 212. . In the main body 208, the heater ground wiring 202 is connected to the ground wiring 214 via the leak detection mechanism 215, and the ground wiring 214 is connected to the ground wiring 213 connected to the ground power source. The logic ground wiring 205 is connected to the ground wiring 213. In the illustrated example, three types of power supplies are shown. However, the number of power supplies is not limited to this, and leak detection mechanisms are also arranged corresponding to all power supplies. It may be arranged only in.

FIG. 3 is a plan view showing an example of the layout of the heater power supply wiring or the heater ground wiring formed on the substrate of the present embodiment.
The substrate 100 is provided with a plurality of heaters 301, a plurality of supply paths 302, and a conductive layer 303 (wiring layer) that is a heater power supply wiring or a heater ground wiring. As described later, the substrate 100 includes a silicon base material and an insulating film formed thereon. The conductive layer 303 is a so-called solid layer provided inside the insulating film, and is arranged at a predetermined interval from the wall surface 304 forming each supply path 302 as shown in the figure, so that the substrate 100 is viewed in plan view. Then, it arrange | positions so that the supply path 302 may be surrounded. As a result, the wiring area of the conductive layer 303 is increased to reduce the wiring resistance against the increasing tendency of the heater driving current accompanying the increase in the substrate area, the higher density of the heater 301, and the higher potential of the heater power supply in recent years. Can be suppressed. As a result, it is possible to suppress the influence due to the variation in the ejection energy and realize good image formation. A protective film may be formed on the wall surface 304 of the supply path 302.

Further, when the conductive layer 303 is disposed as described above, the protective film and the insulating film are dissolved by the ink through the supply path 302, and the wall surface 304 of the supply path 302 is retracted to expose the conductive layer 303 to the supply path 302. Or the heater ground wiring contacts the ink. For example, when the heater power supply wiring comes into contact with the ink, a leakage path from the heater power supply wiring to the silicon substrate or other wiring is generated through the ink, and a leakage current flows. Further, when the protective film on the heater is connected to, for example, a ground potential or a certain potential, a leak path also occurs from the ink to the protective film.
On the other hand, since a large current for driving the heater flows, the heater ground wiring is often at a potential higher than the ground potential of the silicon substrate. For this reason, when the heater ground wiring comes into contact with ink, a leakage current may flow from the heater ground wiring to the silicon substrate (ground potential) through the ink.
In the present embodiment, even when such a leakage current occurs, the power leakage detection mechanism is provided corresponding to each power supply as described above, so that the current or voltage is detected using this power leakage detection mechanism. The occurrence of a leakage current can be detected based on the change in. Thereby, dissolution of the protective film or insulating film by ink can be detected as a power supply leak. Therefore, it is possible to stop the liquid discharge operation or replace the liquid discharge head when a power supply leak is detected. As a result, it is possible to prevent the liquid discharge head from causing a malfunction. It becomes possible. In particular, the heater power supply wiring is a wiring for supplying a power supply potential to the heater, and a higher potential (for example, about 32 V) is applied to heater wiring, logic power supply wiring, and logic ground wiring, which are other wiring layers. For this reason, since the leak current generated when the heater power supply wiring contacts the ink is large, the leak can be detected with high sensitivity. Therefore, a configuration in which a power supply leak detection mechanism is provided for the heater power supply wiring is more preferable. If the ink is in contact with the silicon base material and connected to the ground potential, for example, even if a leak path from the heater power supply wiring occurs, the leak current flows to the silicon base material. Can be minimized.

  In order to detect dissolution by ink through the supply path 302, for example, a configuration in which a linear wiring is arranged around the supply path 302 to detect a change in resistance value, disconnection, or leakage current is also conceivable. However, in such a configuration, the end portions of the wiring cannot be connected to secure a current path, so that there is a place where the wiring is not always arranged around the supply path 302, and ink is generated at that place. If dissolution occurs, it cannot be detected. On the other hand, in this embodiment, since the conductive layer 303 is disposed so as to surround the entire circumference of the supply path 302 when the substrate 100 is viewed in plan, it is possible to more reliably detect dissolution by ink. .

  FIG. 4A and FIG. 4B are schematic cross-sectional views along the line AA in FIG. 3 and show a configuration example of the substrate of the present embodiment. 4A corresponds to the case where the heater power supply wiring is arranged around the supply path 302, and FIG. 4B corresponds to the case where the heater ground wiring is arranged.

As shown in FIGS. 4A and 4B, the substrate 100 includes a silicon base material 401, an interlayer insulating film 402, and four wiring layers 403 to 406. The interlayer insulating film 402 is formed on the silicon base material 401, and the four wiring layers 403 to 406 are formed apart from each other in the thickness direction of the substrate 100 with the interlayer insulating film 402 interposed therebetween. A protective film 407 is formed on the interlayer insulating film 402.
The first wiring layer 403 is a wiring layer including at least one of a logic signal wiring, a logic power supply wiring, and a logic ground wiring for transmitting a logic signal to a logic circuit such as a heater selection circuit or a recording data supply circuit. Similar to the first wiring layer 403, the second wiring layer 404 is a wiring layer including at least one of a logic signal wiring, a logic power supply wiring, and a logic ground wiring. Note that the first wiring layer 403 and the second wiring layer 404 may be layers having the same function. For example, each of the first wiring layer 403 and the second wiring layer 404 includes any of a logic signal wiring, a logic power supply wiring, and a logic ground wiring. You can leave. Alternatively, the first wiring layer 403 and the second wiring layer 404 may be layers having different functions. For example, the first wiring layer 403 includes logic signal wiring, and the second wiring layer 404 includes Logic power supply wiring and logic ground wiring may be included. The third wiring layer 405 is a solid wiring that is a heater power supply wiring, and the fourth wiring layer 406 is a solid wiring that is a heater ground wiring. Here, the solid wiring is a wiring provided so as to be electrically connected to the plurality of heater arrays 102 in common, and a wide wiring area is ensured over the surface of the substrate 100. It is the structure which can suppress.
In the configuration example shown in FIGS. 4A and 4B, the leakage current is detected using the third wiring layer 405 or the fourth wiring layer 406, and thus the first wiring layer 403 and the first wiring layer 403 The second wiring layer 404 may not be provided so as to surround the supply path 302. The first wiring layer 403 and the second wiring layer 404 are arranged by routing a plurality of wirings having different functions such as a logic signal wiring, a logic power supply wiring, and a logic ground wiring. Therefore, normally, the first wiring layer 403 and the second wiring layer 404 are not solid wirings, and their wiring resistances are higher than those of the third wiring layer 405 and the fourth wiring layer 406.

In the configuration example shown in FIG. 4A, among the four wiring layers 403 to 406, the third wiring layer 405 that is the heater power supply wiring is arranged closest to the wall surface 304 of the supply path 302. Therefore, dissolution of the interlayer insulating film 402 by ink through the supply path 302 can be detected as a heater power supply leak. In this configuration example, since the heater power supply is a high potential power supply (for example, about 32 V), it becomes easy to detect a current change due to a leak current, and the occurrence of a power supply leak can be detected with higher sensitivity. That is, from the viewpoint of detection sensitivity of the occurrence of power supply leakage, the configuration in which the third wiring layer 405 that is the heater power supply wiring is provided closer to the wall surface 304 of the supply path 302 as compared with the other wiring layers as described above. Is preferred.
In the configuration example shown in FIG. 4B, among the four wiring layers 403 to 406, the fourth wiring layer 406 that is a heater ground wiring is arranged closest to the wall surface 304 of the supply path 302. Therefore, when the potential of the heater ground wiring (reference potential) is higher than the ground potential, dissolution of the interlayer insulating film 402 by ink through the supply path 302 can be detected as a leakage of the ground power supply. In this configuration example, since a leak current flows from the heater ground wiring, the influence of the leak current can be minimized.

  Of the four wiring layers 403 to 406, which wiring layer is used as a layer including which wiring is not limited to the above-described example, and is arbitrary. For example, the four wiring layers 403 to 403 Any of 406 may constitute the heater power supply wiring. Further, the number of wiring layers is not limited to four, and may be five or more. In that case, it is arbitrary which wiring layer includes which wiring.

(Second Embodiment)
FIG. 5A and FIG. 5B are diagrams corresponding to the schematic cross-sectional view along the line AA in FIG. 3, showing a configuration example of the substrate according to the second embodiment of the present invention.
Wirings arranged around the supply path 302 to detect dissolution of the interlayer insulating film 402 by ink are not limited to heater power supply wiring or heater ground wiring, and may be logic power supply wiring. That is, the dissolution of the interlayer insulating film 402 by the ink through the supply path 302 may be detected as a leakage of the logic power source. In the present embodiment, of the four wiring layers 403 to 406, the first wiring layer 403 or the second wiring layer 404 including the logic power supply wiring is disposed closest to the wall surface 304 of the supply path 302. This is different from the first embodiment. Other configurations are the same as those of the first embodiment, and only differences from the first embodiment will be described below.

In the configuration example shown in FIG. 5A, the first wiring layer 403 is disposed closest to the wall surface 304 of the supply path 302. As described above, the first wiring layer 403 is a wiring layer including at least one of a logic signal wiring, a logic power supply wiring, and a logic ground wiring. Here, the first wiring layer 403 includes at least a logic power supply wiring. In addition, the wiring layer disposed closest to the wall surface 304 of the supply path 302 in the first wiring layer 403 is a logic power supply wiring. Therefore, when the dissolution of the interlayer insulating film 402 by the ink through the supply path 302 proceeds and the ink contacts the first wiring layer 403, the above-described dissolution by the ink through the supply path 302 is performed on the same principle as in the case of the heater power supply. Can be detected as a leakage of the logic power supply. At this time, since the potential of the logic power supply is lower than that of the heater power supply (for example, about 3.3 V), the leakage current from the logic power supply is relatively small, so that the influence of the leakage current can be minimized. it can. Furthermore, the detection of leakage of the logic power supply is advantageous in that monitoring during image formation is easier than in the case of a heater power supply through which current flows during image formation.
In the configuration example shown in FIG. 5B, the second wiring layer 404 is disposed closest to the wall surface 304 of the supply path 302. As in the configuration example shown in FIG. The second wiring layer 404 includes at least logic power supply wiring. In addition, the wiring layer arranged closest to the wall surface 304 of the supply path 302 in the second wiring layer 404 is a logic power supply wiring. Therefore, similarly to the configuration example shown in FIG. 5A, the dissolution of the interlayer insulating film 402 by the ink through the supply path 302 can be detected as a leakage of the logic power supply.

(Third embodiment)
6 (a), 6 (b), 7 (a), and 7 (b) show a configuration example of the substrate according to the third embodiment of the present invention, taken along line AA in FIG. It is a figure corresponding to the schematic sectional drawing in alignment with.
This embodiment is different from the first embodiment in that two of the four wiring layers 403 to 406 are disposed closer to the wall surface 304 of the supply path 302 than the other wiring layers. Is different. Other configurations are the same as those of the first and second embodiments, and only differences from the first and second embodiments will be described below.

In the configuration example shown in FIG. 6A, a third wiring layer 405 that is a heater power supply wiring and a fourth wiring layer 406 that is a heater ground wiring are arranged close to the wall surface 304 of the supply path 302. The third wiring layer 405 and the fourth wiring layer 406 are disposed so as to surround the supply path 302 when the substrate 100 is viewed in plan. Accordingly, when dissolution of the interlayer insulating film 402 by the ink through the supply path 302 proceeds, one or both of the third wiring layer 405 and the fourth wiring layer 406 first come into contact with the ink. Therefore, the dissolution of the interlayer insulating film 402 by the ink can be detected by one or both of the leak of the heater power supply and the leak of the ground power supply, and the detection accuracy of the dissolution by the ink can be further improved. In addition, when both the third wiring layer 405 and the fourth wiring layer 406 are in contact with ink, the leakage current is changed from the third wiring layer 405 which is a heater power wiring having a high potential to the fourth wiring which is a heater ground wiring. A current flows to the wiring layer 406 and then flows to the silicon base material 401. As described above, the configuration example of FIG. 6A is a third wiring layer having a large potential difference compared to the configuration example of FIG. 4A in which only the heater power supply wiring is close to the wall surface 304 of the supply path 302. Leakage current can flow from 405 to the fourth wiring layer 406. Therefore, it becomes possible to detect the leak current with higher sensitivity. In addition, since the leakage current flows from the fourth wiring layer 406 to the silicon base material 401, heat generation due to the leakage current and influence on other circuits can be suppressed. Here, as described above, the fourth wiring layer 406 that is the heater ground wiring is configured as a solid wiring, and is wired more than the first wiring layer 403 and the second wiring layer 404 that are wiring connected to the logic circuit. Resistance is low. For this reason, also from the viewpoint of suppressing the heat generation due to the leakage current and the influence on other circuits, the third wiring layer 405 that is the heater power supply wiring and the fourth wiring layer 406 that is the heater ground wiring are included in the supply path 302. A configuration provided close to the wall surface 304 is preferable. In this configuration, since the third wiring layer 405 and the fourth wiring layer 406 are both close to the wall surface 304 of the supply path 302 and have a large area, the wiring resistance can be kept low. Therefore, it is possible to further suppress the influence on the image formation due to the variation in ejection energy.
Note that in the configuration example illustrated in FIG. 6A, the first wiring layer 403 and the second wiring layer 404 may not be provided so as to surround the supply path 302.

  In the configuration example shown in FIG. 6B, a first wiring layer 403 including at least a logic power supply wiring and a second wiring layer 404 including at least a logic power supply wiring are arranged in proximity to the wall surface 304 of the supply path 302. Yes. Therefore, also in this case, if one of the first wiring layer 403 and the second wiring layer 404 is in contact with ink, the dissolution of the interlayer insulating film 402 by the ink through the supply path 302 is detected as a leakage of the logic power supply. can do. Therefore, the detection accuracy of dissolution by ink can be further improved. In the configuration example shown in FIG. 6B, one of the first wiring layer 403 and the second wiring layer 404 may include at least a logic power supply wiring, and the other may include at least a logic ground wiring. Also in this case, when both the first wiring layer 403 and the second wiring layer 404 are in contact with ink, a leak current flows between the first wiring layer 403 and the second wiring layer 404 through the ink. It becomes possible to detect the dissolution of the interlayer insulating film 402 by the ink.

In the configuration example shown in FIG. 7A, the third wiring layer 405 and the first wiring layer 403 are arranged close to the wall surface 304 of the supply path 302, but the first wiring layer 403 is at least a logic. Includes ground wiring. Further, in the configuration example shown in FIG. 7B, the third wiring layer 405 and the second wiring layer 404 are arranged close to the wall surface 304 of the supply path 302, but are shown in FIG. 7A. Similar to the configuration example, the second wiring layer 404 includes at least a logic ground wiring. Therefore, in the configuration example shown in FIGS. 7A and 7B, when both of the two wiring layers are in contact with ink, the leakage current flows from the heater power supply wiring to the logic ground wiring through the ink, and the influence thereof. Can be suppressed.
In the configuration example shown in FIGS. 7A and 7B, a fourth wiring layer 406 (heater ground wiring) is connected to the supply path 302 instead of the third wiring layer 405 (heater power wiring). It may be arranged close to the wall surface 304. Also in this case, if both of the two wiring layers are in contact with ink, a leakage path to the logic ground wiring through the ink can be generated, and the influence of the leakage current can be suppressed.
In the configuration in which the two wiring layers are arranged closer to the wall surface 304 of the supply path 302 than the other wiring layers as in the present embodiment, one of the two wiring layers is a heater power supply wiring or the like. A wiring for supplying a power supply potential, such as a logic power supply wiring. The other wiring layer of the two wiring layers is a wiring for supplying a reference potential such as a heater ground wiring or a logic ground wiring, and is connected to the silicon substrate 401. One wiring layer has a higher potential than the other wiring layer, and a leakage current flows from the ground wiring to the silicon substrate 401, so that the influence of the leakage current can be suppressed.

In the above-described embodiment, there is a case where wiring (power supply wiring, ground wiring, logic power supply wiring) used for driving a heating element (heater) is used to detect dissolution of the protective film or insulating film by ink. Explained with an example. By detecting the leakage current using such a wiring, the leakage current can be detected without providing a dedicated wiring or pad for detecting the leakage current. In order to detect leakage with high sensitivity, it is preferable to detect leakage current using wiring to which a potential of 3.0 V or higher is applied, such as heater power wiring and logic power wiring. In order to detect leakage with higher sensitivity, it is more preferable to detect leakage current using a wiring to which a potential of 20 V or more is applied, such as a heater power supply wiring.
The configuration in which the conductive layer connected to the leak detection mechanism surrounds the supply path 302 when the substrate 100 is viewed in plan has been described. However, in addition to the supply path 302, a recovery path for collecting ink is provided. If present, it may be provided so as to surround the recovery path. In other words, the conductive layer only needs to be provided so as to surround the flow path that penetrates the substrate 100 such as the supply path 302 and the recovery path.

(Inkjet recording device)
An ink jet recording apparatus 1000 (hereinafter, also referred to as “recording apparatus”) that performs recording by ejecting ink will be described with reference to FIG. The recording apparatus 1000 includes a transport unit 1 that transports the recording medium 2, and a line-type liquid ejection head unit 3 that is disposed substantially orthogonal to the transport direction of the recording medium 2. Is a line type recording apparatus that performs continuous recording in one pass while continuously or intermittently transporting the recording medium. The recording medium 2 is not limited to cut paper but may be continuous roll paper. The liquid discharge head unit 3 is capable of full color printing with four colors of ink of cyan (C) / magenta (M) / yellow (Y) / black (K). In addition, the liquid discharge head unit 3 is electrically connected to a control unit of the recording apparatus 1000 for transmitting electric power and discharge control signals to the liquid discharge head unit 3.

(Liquid discharge head unit)
FIG. 9 is a perspective view of the liquid discharge head unit 3 according to the present embodiment. The liquid discharge head unit 3 has a recording element substrate (liquid discharge head) 10 that can discharge four color inks of C / M / Y / K by a single recording element substrate (liquid discharge head) 10 on a straight line 15. This is a line-type liquid discharge head unit arranged in an array (arranged inline).
As shown in FIG. 9, the liquid discharge head unit 3 includes a recording element substrate (liquid discharge head) 10, a flexible wiring board 40, and an electric wiring board 90. The electrical wiring board 90 includes a signal input terminal 91 and a power supply terminal 92. The signal input terminal 91 and the power supply terminal 92 are electrically connected to the control unit of the recording apparatus 1000, and an ejection driving signal and power necessary for ejection are supplied to the recording element substrate (liquid ejection head) via these terminals. ) 10.

  The present embodiment is a so-called line-type head unit having a length corresponding to the width of the recording medium 2, but is a so-called serial type liquid discharge unit that performs recording while scanning the recording medium 2. The present invention can also be applied to a head unit. As the serial type liquid discharge head unit, for example, there is a configuration in which a recording element substrate for black ink and a recording element substrate for color ink are mounted.

100 Substrate 200 Liquid discharge head 302 Supply path (flow path)
303 Conductive layer (wiring layer)

Claims (20)

A substrate including an insulating film;
An energy generating element that is provided on the substrate and generates energy used for discharging a liquid;
A flow path formed through the substrate and communicating with a discharge port for discharging a liquid;
A wiring layer formed inside the insulating film of the substrate and used for driving the energy generating element, arranged at a distance from a wall forming the flow path, and when the substrate is viewed in plan view A wiring layer disposed around the flow path;
A liquid discharge head.   The liquid ejection head according to claim 1, wherein the wiring layer is connected to a leak detection mechanism that detects a leakage current flowing from the wiring layer.   The liquid discharge head according to claim 1, wherein the wiring layer is a power supply wiring that supplies a power supply potential to the energy generating element.   The liquid ejection head according to claim 1, wherein the wiring layer is a power supply wiring that supplies a power supply potential to a logic circuit for driving the energy generating element. Another wiring layer formed inside the insulating film and spaced apart in the thickness direction of the wiring layer and the substrate and used to drive the energy generating element, and spaced from a wall forming the flow path And further having other wiring layers arranged
The liquid ejection head according to claim 1, wherein the wiring layer is disposed closer to a wall forming the flow path than the other wiring layer.   The liquid ejection head according to claim 5, wherein the wiring layer is a power supply wiring for supplying a power supply potential to the energy generating element.   3. The liquid ejection head according to claim 1, further comprising two wiring layers formed in the insulating film so as to be separated from each other in the thickness direction of the substrate.   The liquid ejection head according to claim 7, wherein one of the two wiring layers has a higher potential than the other of the two wiring layers. A wall that is formed inside the insulating film and spaced apart in the thickness direction of the two wiring layers and the substrate and is used to drive the energy generating element, and forms the flow path Having other wiring layers spaced from
9. The liquid ejection head according to claim 7, wherein the two wiring layers are disposed closer to a wall forming the flow path than the other wiring layers.   One of the two wiring layers constitutes a power supply wiring for supplying a power supply potential to the energy generating element, and the other of the two wiring layers provides a ground wiring for supplying a reference potential to the energy generating element. The liquid discharge head according to claim 9, comprising:   The other wiring layer includes a logic signal wiring for transmitting a signal to a logic circuit for driving the energy generating element, a power wiring for supplying a power potential to the logic circuit, and a ground for supplying a reference potential to the logic circuit. The liquid discharge head according to claim 10, comprising at least one of wiring.   One of the two wiring layers constitutes a power supply wiring for supplying a power supply potential to the energy generating element, and the other of the two wiring layers has a reference potential for a logic circuit for driving the energy generating element. The liquid discharge head according to claim 9, comprising a ground wiring for supplying the liquid.   One of the two wiring layers constitutes a power supply wiring for supplying a power supply potential to a logic circuit for driving the energy generating element, and the other of the two wiring layers drives the energy generating element. The liquid discharge head according to claim 9, comprising a ground wiring for supplying a reference potential to a logic circuit for the same.   The liquid ejection head according to claim 1, wherein a potential of 3.0 V or more is applied to the wiring layer.   The liquid discharge head according to claim 1, wherein the liquid supplied to the flow path is connected to a ground potential. A substrate including an insulating film;
An energy generating element that is provided on the substrate and generates energy used for discharging a liquid;
A flow path formed through the substrate and communicating with a discharge port for discharging a liquid;
A wiring layer formed inside the insulating film of the substrate and used for driving the energy generating element, arranged at a distance from a wall forming the flow path, and when the substrate is viewed in plan view A wiring layer disposed around the flow path;
A liquid ejection head having
A leakage detection mechanism that is electrically connected to the wiring layer and detects a leakage current flowing from the wiring layer;
A liquid ejection apparatus having   The liquid ejection apparatus according to claim 16, wherein the wiring layer is a power supply wiring that supplies a power supply potential to the energy generating element.   17. The liquid ejection apparatus according to claim 16, comprising two wiring layers formed in the insulating film so as to be separated from each other in the thickness direction of the substrate. A wall that is formed inside the insulating film and spaced apart in the thickness direction of the two wiring layers and the substrate and is used to drive the energy generating element, and forms the flow path Having other wiring layers spaced from
The liquid ejection apparatus according to claim 18, wherein the two wiring layers are arranged closer to a wall forming the flow path than the other wiring layers. One of the two wiring layers constitutes a power supply wiring for supplying a power supply potential to the energy generating element, and the other of the two wiring layers provides a ground wiring for supplying a reference potential to the energy generating element. The liquid ejection apparatus according to claim 19, comprising:

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