Liquid ejection head and manufacturing method thereof

Abstract

To provide a liquid discharge head in which a height of a sealant surface is adequately adjusted, and a manufacturing method of the same.SOLUTION: A producing method of a liquid discharge head includes: a process of preparing a structure which has a support member having a substrate installation surface, an element substrate arranged on the substrate installation surface and having a discharge port for discharging a liquid, a wiring substrate which is arranged on the substrate installation surface, is electrically connected to the element substrate, and has a height from the substrate installation surface lower than the element substrate, and a cover which is arranged on the substrate installation surface so as to surround a periphery of the element substrate and cover the wiring substrate when viewing the substrate installation surface from a direction vertical to the substrate installation surface; and a process of pouring a sealant in a gap between the element substrate and the cover. The element substrate includes a recessed part for crossing between an exposed surface exposed from the cover and an end surface, and detects an inflow of the sealant into the recessed part, and finishes injection of the sealant.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection head and a method for manufacturing the same. [Background technology]

[0002] In recent years, various silicon devices have been applied to various devices such as liquid ejection heads such as inkjet recording heads, thermal sensors, pressure sensors, acceleration sensors, etc. In the manufacture of these various silicon devices, micromachining technology, a type of fine processing technology, is used to meet various demands such as higher density, higher precision, cost reduction, and faster tact times.

[0003] A liquid ejection head has an element substrate in which ejection ports for ejecting liquid are formed, and a wiring substrate electrically connected to the element substrate. The element substrate has a silicon substrate, and the edge surfaces of the element substrate are bare silicon. The edge surfaces (silicon) of the element substrate are at risk of being eroded by high-pH liquids, so they need to be sealed (protected) with a sealant. Furthermore, to ensure the electrical reliability of the connection between the element substrate and the wiring substrate, the connection surface also needs to be sealed with a sealant.

[0004] Patent Document 1 discloses an ink jet print head having a sealant guide groove on the outside of the ejection port, one side of the sealant guide groove being open in the ejection direction. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-95959 Summary of the Invention [Problem to be solved by the invention]

[0006] When liquid is ejected from a liquid ejection head, the liquid adheres to the ejection port surface due to the influence of minute droplets (mist) that are generated along with the ejected droplets. If the liquid adhering to the ejection port surface gets into the ejection port, it may affect ejection, so it is preferable to remove the liquid adhering to the ejection port surface. As an example, the liquid adhering to the ejection surface is sucked up by a vacuum while being wiped with a wiper (vacuum wiping). If the height of the sealant surface is higher than the height of the element substrate surface, gaps will be created, a vacuum will not be generated by the vacuum, and wiping will not be effective. If the height of the sealant surface is too low compared to the height of the element substrate surface, gaps will be created, a vacuum will not be generated by the vacuum, and wiping will not be effective.

[0007] However, in conventional liquid ejection heads such as the inkjet printer head disclosed in Patent Document 1, the height of the sealant surface may be higher or lower than the height of the element substrate surface.

[0008] An object of the present invention is to provide a liquid ejection head in which the height of the sealant surface is appropriately adjusted, and a method for manufacturing the same. [Means for solving the problem]

[0009] A method for producing a liquid ejection head according to the present invention includes: a support member having a substrate mounting surface; an element substrate provided on the substrate mounting surface and having ejection ports for ejecting liquid; a wiring board provided on the substrate mounting surface and electrically connected to the element substrate, the wiring board having a height from the substrate mounting surface that is lower than that of the element substrate; and a wiring board having a height from the substrate mounting surface that is lower than that of the element substrate when the substrate mounting surface is viewed from a direction perpendicular to the substrate mounting surface. the step of preparing a structure having a cover provided on the substrate mounting surface so as to surround the periphery of the element substrate and cover the wiring substrate, and the step of injecting a sealant into the gap between the element substrate and the cover, wherein the element substrate has a recess formed therein spanning the exposed surface exposed from the cover and the end surface, and the flow of the sealant into the recess is detected and the injection of the sealant is terminated.

[0010] The liquid ejection head of the present invention comprises a support member having a substrate mounting surface, an element substrate provided on the substrate mounting surface and having an ejection port for ejecting liquid, a wiring board provided on the substrate mounting surface and electrically connected to the element substrate, the wiring board being lower in height from the substrate mounting surface than the element substrate, a cover provided on the substrate mounting surface so as to surround the periphery of the element substrate and cover the wiring board when the substrate mounting surface is viewed from a direction perpendicular to the substrate mounting surface, and a sealant filling the gap between the element substrate and the cover, wherein a recess is formed in the element substrate spanning the exposed surface exposed from the cover and the end face, and the sealant is filled up to the position of the recess. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a liquid ejection head in which the height of the sealant surface is appropriately adjusted, and a method for manufacturing the same. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a plan view showing an example of a liquid ejection head (after sealing) according to the present embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing an example of a liquid ejection head according to the present embodiment (after sealing). [Figure 3] FIG. 2 is a plan view showing an example of a liquid ejection head (before sealing) according to the present embodiment. [Figure 4] 5A to 5C are diagrams illustrating an example of a method for injecting a first sealant according to the present embodiment. [Figure 5] 10A to 10C are diagrams illustrating another example of a method for injecting the first sealant according to the present embodiment. [Figure 6] 10A to 10C are diagrams illustrating another example of a method for injecting the first sealant according to the present embodiment. [Figure 7] FIG. 10 is a cross-sectional view showing another example of the liquid ejection head according to the present embodiment. [Figure 8] FIG. 10 is a cross-sectional view showing another example of the liquid ejection head according to the present embodiment. [Figure 9] FIG. 10 is a perspective view showing another example of the liquid ejection head according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIGS. 1 and 3 are plan views of a liquid ejection head 1 (top views of the liquid ejection head 1 viewed from a direction perpendicular to the substrate mounting surface of a support member 6), and FIG. 2 is a cross-sectional view of the AA portion of FIG. 1 (cross-sectional view of the liquid ejection head 1 viewed from a direction parallel to the substrate mounting surface of the support member 6). The liquid ejection head 1 is used in a liquid recording device that ejects liquid (ink) onto a recording medium such as paper, such as a printhead (inkjet recording head) of an inkjet printer. The liquid ejection head 1 includes a support member 6 having a substrate mounting surface, an element substrate 2 provided on the substrate mounting surface, a wiring substrate 5 provided on the substrate mounting surface, and a cover 7 provided on the substrate mounting surface. The element substrate 2 and the wiring substrate 5 are electrically connected, and the connection is sealed with a first sealant 8 and a second sealant 9. The periphery (edges) of the element substrate 2 are also sealed with the first sealant 8. 1 and 2 show the state after sealing with the first sealant 8 and the second sealant 9, and Fig. 3 shows the state before sealing with the first sealant 8 and the second sealant 9. Hereinafter, for each component provided on the support member 6, the surface facing the substrate mounting surface of the support member 6 will be referred to as the "bottom surface (rear surface)" and the surface opposite the back surface will be referred to as the "top surface (front surface)."

[0014] The support member 6 is a member that supports the element substrate 2 and the wiring substrate 5, and for example, the element substrate 2 and the wiring substrate 5 are fixed (bonded) to the substrate mounting surface of the support member 6 with an adhesive 10. As long as the element substrate 2 and the wiring substrate 5 can be provided on the substrate mounting surface, there are no particular limitations on the size, shape, material, etc. of the support member 6. For example, the material of the support member 6 includes resin, ceramic, metal, etc. A variety of materials can be selected. In this embodiment, a thermosetting adhesive is used to fix the element substrate 2 and the wiring substrate 5 to the support member 6. Therefore, it is preferable to use a support member made of alumina, which has excellent heat resistance, as the support member 6.

[0015] The cover 7 is a protective member for protecting the wiring substrate 5 bonded to the support member 6. When the substrate mounting surface of the support member 6 is viewed from a direction perpendicular to the substrate mounting surface, the cover 7 is provided to surround the element substrate 2 and cover the wiring substrate 5. A first sealant 8 is poured into the gap between the element substrate 2 (the end surface of the element substrate 2) and the cover 7. The size, shape, material, and the like of the cover 7 are not particularly limited as long as the cover 7 can protect the wiring substrate 5. However, to reliably cover the periphery of the element substrate 2 with the first sealant 8, it is preferable that the height of the upper surface of the cover 7 (height from the substrate mounting surface of the support member 6) be higher than the height of the upper surface of the element substrate 2. When the substrate mounting surface of the support member 6 is flat, it is preferable that the thickness of the cover 7 be greater than the thickness of the element substrate 2. The "height" can also be interpreted as "the position of the support member 6 in a direction perpendicular to the substrate mounting surface, etc.", and the "thickness" can also be interpreted as "the size of the support member 6 in a direction perpendicular to the substrate mounting surface, etc." The material of the cover 7 can be selected from various materials including resin, ceramic, metal, etc. In this embodiment, the cover 7 is fixed to the wiring board 5 and the support member 6 using a thermosetting adhesive. Therefore, it is preferable to use an alumina support member as the cover 7.

[0016] The element substrate 2 includes a silicon substrate (not shown), a plurality of electrode terminals 3 arranged on the upper surface of the silicon substrate, energy generating elements (not shown) that generate energy for discharging the liquid, and a resin layer 4 having discharge ports for discharging the liquid. The silicon substrate has a thickness of, for example, approximately 0.6 mm to 1.0 mm. The element substrate 2 also has electrical wiring (not shown) that electrically connects each of the electrode terminals 3 to the energy generating elements. The element substrate 2 has an installation surface (lower surface) that faces the substrate installation surface of the support member 6, and an exposed surface (upper surface) that is the surface opposite the installation surface and is exposed from the cover 7. The exposed surface is the mounting surface of the element substrate 2 (the surface on which various elements are formed). The element substrate 2 has a sealant detection groove 11 (recess) at the boundary between the exposed surface and an end surface of the support member 6 that is perpendicular to the substrate installation surface. The sealant detection groove 11 is intended to detect the timing when the injection (application) of the first sealant 8 should be terminated, and is formed across the exposed surface and the end surface so as to have a portion that opens at the exposed surface (exposed surface opening) and a portion that opens at the end surface (end surface opening).

[0017] The energy generating elements convert power supplied from the electrode terminals 3 via electrical wiring into thermal energy. When the thermal energy generated by the energy generating elements is applied to a liquid such as ink, the liquid is ejected from ejection ports formed in the resin layer 4. The electrical wiring in the element substrate 2 is formed on a silicon substrate using, for example, a film formation technique. The element substrate 2 includes a plurality of ejection ports corresponding to the energy generating elements, a plurality of liquid flow paths each communicating with the plurality of ejection ports, and a liquid supply path for supplying liquid to the plurality of liquid flow paths. The liquid supply path is formed by a hole that penetrates from the top surface to the bottom surface of the silicon substrate. The plurality of ejection ports and the plurality of liquid flow paths are formed on the silicon substrate using photolithography technology.

[0018] A plurality of electrode terminals 3 connected to the electrical wiring are arranged along one side of the upper surface of the element substrate 2 to form a terminal row. From the viewpoints of planarity and resistance when transmitting electrical signals, the electrode terminals 3 are preferably gold-plated terminals. Although not shown, in this embodiment, a plurality of ejection ports and energy generating elements are arranged along the plurality of electrode terminals 3 on the element substrate 2.

[0019] The sealant detection groove 11 can be formed by a physical method using a blade, a scribing tool, a laser, or the like, or by a chemical method using dry etching or wet etching with a resist as a mask. They may be formed together when forming the substrate 2, or may be formed individually after the element substrates 2 are separated from the silicon wafer into chips.

[0020] The wiring board 5 is formed by sandwiching a conductive copper foil printed wiring between two thin, flexible insulating films and laminating them together. The height of the upper surface of the wiring board 5 is lower than the height of the upper surface of the element substrate 2. In this embodiment, the wiring board 5 is thinner than the element substrate 2. For example, a flexible substrate having a thickness of 0.1 mm to 0.3 mm can be used as the wiring board 5. By making one of the two films to be laminated smaller than the other, the ends of the copper foil printed wiring are exposed when the two films are laminated together. The exposed ends of the copper foil printed wiring are used as connection terminals and are connected to the multiple electrode terminals 3 of the element substrate 2 by wire bonding. This electrically connects the element substrate 2 and the wiring board 5.

[0021] After preparing a structure as shown in FIG. 3 (liquid ejection head 1 before the periphery of the element substrate 2 is sealed with the first sealant 8), the periphery of the element substrate 2 is sealed with the first sealant 8. A method of sealing the periphery of the element substrate 2 with the first sealant 8 will be described. FIG. 4(a) is a plan view showing the liquid ejection head 1 before the periphery of the element substrate 2 is sealed with the first sealant 8. The liquid ejection head 1 in FIG. 4(a) is obtained by bonding the element substrate 2 and the wiring board 5 to the support member 6, electrically connecting the element substrate 2 and the wiring board 5 bonded to the support member 6 by wire bonding, and then bonding the cover 7 to the wiring board 5 and the support member 6.

[0022] The first sealant 8 is preferably a curable liquid resin, such as an epoxy resin, an acrylic resin, an epoxy acrylate resin, an imide resin, or an amide resin. The first sealant 8 may be cured by any of several methods, including two-component curing (mixing a curing agent), thermal curing (heat curing), or UV curing (UV curing). Furthermore, the first sealant 8 preferably has a suitable fluidity so that it can fill the space below the wires (not shown) between the element substrate 2 and the wiring substrate 5 and uniformly seal the periphery of the element substrate 2. For example, the viscosity of the first sealant 8 is preferably 3 Pa·s or more and 320 Pa·s or less, and more preferably 3 Pa·s or more and 40 Pa·s or less. A sealant with a high viscosity may be used as the first sealant 8. In this case, the viscosity of the first sealant 8 may be reduced by increasing the temperature of the first sealant 8.

[0023] A simple method for filling the space below the wires between the element substrate 2 and the wiring substrate 5 and the space around the element substrate 2 with the first sealant 8 is injection (application) by a dispense method. Specifically, as shown in FIG. 4(a), a point on the periphery of the element substrate 2 is determined as an injection position 12, and the first sealant 8 is injected from the injection position 12 into the space between the element substrate 2 and the cover 7. Then, as shown in FIGS. 4(b) to 4(d), the first sealant 8 gradually fills the space around the element substrate 2. Then, as shown in FIG. 4(e), the first sealant 8 flows into the sealant detection groove 11 on the opposite side of the element substrate 2 from the injection position 12. The flow of the first sealant 8 into the sealant detection groove 11 (the first sealant 8 flowing into the sealant detection groove 11) is detected, and the injection of the first sealant 8 is terminated. The flow of the first sealant 8 into the sealant detection groove 11 may be detected, for example, by analyzing a binarized image captured by a camera, or may be physically detected by a sensor inserted into the sealant detection groove 11. By recessing the sealant detection groove 11 from the edge face of the element substrate 2, the first sealant 8 can flow into the sealant detection groove 11 when the height of the surface of the first sealant 8 exceeds the height of the bottom face of the sealant detection groove 11. By recessing the sealant detection groove 11 from the exposed face of the element substrate 2 as well, the flow of the first sealant 8 into the sealant detection groove 11 can be confirmed from outside the structure as shown in FIG. 3. The bottom face of the sealant detection groove 11 is a face adjacent to the edge face of the element substrate 2 or a face facing the same direction as the edge face, for example, a face substantially parallel to the substrate installation surface of the support member 6.

[0024] The method of injecting the first sealant 8 may be a method in which the first sealant 8 is injected without moving the injection position 12 (a method in which the dispense nozzle of the first sealant 8 is not moved) as shown in Figures 4(a) to 4(e), or may not be such a method. For example, as shown in Figures 5(a) to 5(e), the first sealant 8 may be injected while moving the injection position 12 along the periphery of the element substrate 2 (a method in which the dispense nozzle of the first sealant 8 is moved).

[0025] Furthermore, the method for determining the injection position 12 is not particularly limited. Consider a case where a single injection position 12 is determined and the first sealant 8 is injected without moving the injection position 12. In this case, it is preferable to determine the injection position 12 near a position that is point-symmetrical to the sealant detection groove 11 with respect to the center of the element substrate 2 when the substrate mounting surface of the support member 6 is viewed from a direction perpendicular to the substrate mounting surface. In FIG. 4(a), the injection position 12 is determined in this manner. This allows the height of the surface of the first sealant 8 to be higher than the height of the bottom surface of the sealant detection groove 11 over the entire periphery of the element substrate 2. Next, consider a case where a single injection position 12 (starting point) is determined and the first sealant 8 is injected while moving the injection position 12. In this case, it is preferable to determine the starting point of the injection position 12 so that the end point of the injection position 12 is near the position of the sealant detection groove 11 when the substrate mounting surface of the support member 6 is viewed from a direction perpendicular to the substrate mounting surface. In FIG. 5(a), the injection position 12 is determined in this manner. This also makes it possible to make the surface of the first sealant 8 higher than the sealant detection groove 11 over the entire periphery of the element substrate 2.

[0026] Furthermore, the number of injection positions 12 and the number of sealant detection grooves 11 are not particularly limited. For example, as shown in FIGS. 6(a) to 6(e), the first sealant 8 may be injected from two injection positions 12a and 12b. When a plurality of sealant detection grooves 11 are formed, for example, the injection of the first sealant 8 is terminated upon detecting the flow of the first sealant 8 into all of the sealant detection grooves 11. In FIGS. 6(a) to 6(e), four sealant detection grooves 11a to 11d are formed, and the injection of the first sealant 8 is terminated upon detecting the flow of the first sealant 8 into all of the sealant detection grooves 11a to 11d. Although the injection position 12 is not moved in FIGS. 6(a) to 6(e), the injection position 12 may be moved whether the first sealant 8 is injected from a plurality of injection positions 12 or a plurality of sealant detection grooves 11 are formed.

[0027] Furthermore, the shape of the sealant detection groove 11 is not particularly limited. When multiple sealant detection grooves 11 are formed, the depths of the multiple sealant detection grooves 11 from the exposed surface of the element substrate 2 (in the direction perpendicular to the substrate installation surface of the support member 6) may be the same or may be different, as shown in FIG. 7 . However, to effectively perform vacuum wiping, the distance from the exposed surface of the element substrate 2 to the surface of the first sealant 8 is preferably 0.2 mm or less. Therefore, the depth of the sealant detection groove 11 (depth from the exposed surface of the element substrate 2) is preferably 0.2 mm or less. When multiple sealant detection grooves 11 are formed, it is preferable that the depths of all the sealant detection grooves 11 are 0.2 mm or less. This not only enables effective vacuum wiping, but also ensures that the edge of the element substrate 2 is sufficiently sealed (even if there is a portion of the edge of the element substrate 2 that is not sealed with sealant, that portion will be extremely small).

[0028] For example, when two sealant detection grooves 11 with different depths are formed as shown in Fig. 7, the depth of one sealant detection groove 11 may be set to 0.2 mm or the like, and the depth of the other sealant detection groove 11 may be set to 0.1 mm or the like. In Figs. 6(a) to 6(e), the depths of sealant detection grooves 11c and 11d are set to be greater than the depths of sealant detection grooves 11a and 11b. Therefore, the timing at which the first sealant 8 flows into sealant detection grooves 11c and 11d is later than the timing at which the first sealant 8 flows into sealant detection grooves 11a and 11b.

[0029] By forming a plurality of sealant detection grooves 11 with different depths, it is possible to define the upper and lower limits of the height of the surface of the first sealant 8. For example, at least one of the plurality of sealant detection grooves 11 When the flow of the first sealant 8 into the deepest sealant detection groove 11 is detected and the injection of the first sealant 8 is terminated, the surface height of the first sealant 8 becomes the lower limit height. When the flow of the first sealant 8 into the shallowest sealant detection groove 11 is detected and the injection of the first sealant 8 is terminated, the surface height of the first sealant 8 becomes the upper limit height. When the flow of the first sealant 8 into the sealant detection groove 11 of an intermediate depth is detected and the injection of the first sealant 8 is terminated, the surface height of the first sealant 8 becomes the intermediate height.

[0030] As shown in FIGS. 8 and 9, a stepped sealant detection groove 11 may be formed. The sealant detection groove 11 in FIGS. 8 and 9 includes a first bottom surface adjacent to the edge surface of the element substrate 2 and a second bottom surface adjacent to the first bottom surface but shallower than the first bottom surface. The second bottom surface may or may not be adjacent to the edge surface of the element substrate 2. In FIG. 8, the second bottom surface is not adjacent to the edge surface of the element substrate 2, while in FIG. 9, the second bottom surface is adjacent to the edge surface of the element substrate 2. In this case, upper and lower limits of the surface height of the first sealant 8 can be defined. For example, the injection of the first sealant 8 is terminated upon detecting that the first sealant 8 has flowed into the sealant detection groove 11 beyond at least the first bottom surface. If the injection of the first sealant 8 is terminated upon detecting that the first sealant 8 has flowed into the sealant detection groove 11 beyond only the deepest first bottom surface, the surface height of the first sealant 8 will be the lower limit. When the injection of the first sealant 8 is terminated upon detection that the first sealant 8 has flowed into the sealant detection groove 11 beyond the second bottom surface, which is shallower than the first bottom surface, the surface height of the first sealant 8 becomes higher than the lower limit height. When the injection of the first sealant 8 is terminated upon detection that the first sealant 8 has flowed into the sealant detection groove 11 beyond the shallowest bottom surface, the surface height of the first sealant 8 becomes the upper limit height. When the injection of the first sealant 8 is terminated upon detection that the first sealant 8 has flowed into the sealant detection groove 11 beyond the intermediate depth bottom surface, the surface height of the first sealant 8 becomes the intermediate height.

[0031] Furthermore, depending on the type of the first sealant 8, the thickness of the element substrate 2, and the like, the injection of the first sealant 8 may be stopped at the timing when the first sealant 8 has spread around the entire periphery of the element substrate 2. Therefore, in order to be able to detect such timing, instead of the sealant detection groove 11, another recess such as a notch extending from the upper surface to the lower surface of the element substrate 2 may be formed on the end surface of the element substrate 2.

[0032] After the first sealant 8 is injected (applied), a second sealant 9 is applied to the connection portion between the element substrate 2 and the wiring substrate 5 (the portion including the electrode terminals 3 of the element substrate 2, the connection terminals of the wiring substrate 5, and the wires connecting them). The second sealant 9 may be the same as the first sealant 8, or may have a different composition or viscosity from the first sealant 8. Even when a sealant different from the first sealant 8 is used as the second sealant 9, the second sealant 9 can be made of a liquid epoxy resin, acrylic resin, epoxy acrylate resin, imide resin, amide resin, or the like, similar to the first sealant 8. The viscosity of the second sealant 9 is preferably 100 Pa·s or more and 500 Pa·s or less. If the viscosity of the second sealant 9 is 100 Pa·s or more and 500 Pa·s or less, the second sealant 9 can be prevented from flowing off the wires.

[0033] As described above, according to this embodiment, the sealant detection groove 11 (recess) spanning the exposed surface and the end surface is formed in the element substrate 2, and the flow of the first sealant 8 into the sealant detection groove 11 is detected to terminate the injection of the first sealant 8. This makes it possible to manufacture a liquid ejection head in which the height of the sealant surface is appropriately adjusted.

[0034] Examples of the present invention will be described in detail below, but the present invention is not limited to these examples in any way.

[0035] Example 1 In Example 1, a liquid ejection head was fabricated by the following method. First, a plurality of energy A silicon substrate (silicon wafer) was prepared on which a laser-generating element and multiple drive circuits were formed, and on which silicon oxide and silicon nitride membrane films were formed. Resin and resist were then applied to the silicon substrate, followed by exposure and development. Dry etching was performed using the resist (resist pattern) as a mask, forming multiple liquid supply channels and multiple sealant detection grooves in the silicon substrate. The resin layer was then formed into a dry film, which was then transferred to the silicon substrate and patterned to form multiple liquid flow paths and multiple discharge ports. This resulted in a silicon substrate on which multiple element substrates were formed. The silicon substrate was then cut and separated into chips using a dicing sorter to obtain element substrates. The silicon substrate may also be chipped using a laser sorter or the like. A flexible substrate was also obtained as a wiring substrate using a known method. The element substrate and wiring substrate were fixed to an alumina support member with an adhesive, and the element substrate and wiring substrate were electrically connected by wire bonding. A cover was then fixed with an adhesive, resulting in a structure with a space between the element substrate and the cover. An epoxy resin with a viscosity of 40 Pa·s was injected into this space as the first sealant, from a position symmetrical to the sealant detection groove relative to the center of the element substrate 2. The sealant detection groove was photographed from above with a camera and binarized. The flow of the first sealant into the sealant detection groove was detected based on the binarized image, and the injection of the first sealant was stopped when this flow was detected. A second sealant with a viscosity of 320 Pa·s was then applied to the wire connecting the element substrate and the wiring board. The resulting structure was then bonded to a resin tank to obtain a liquid ejection head. In this liquid ejection head, the height of the surface of the first sealant around the periphery of the element substrate was 0.15 mm above the top surface of the element substrate, which was within the appropriate range.

[0036] Example 2 In Example 2, sealant detection grooves were formed in two locations. The first sealant was injected while the dispensing nozzle for the first sealant was scanned in one direction along the periphery of the element substrate. Other than these, the method was the same as Example 1. In the liquid ejection head obtained by the method of Example 2, the height of the surface of the first sealant around the periphery of the element substrate was 0.10 mm above the upper surface of the element substrate, which was appropriate.

[0037] Example 3 In Example 3, sealant detection grooves were formed in four locations with different depths. The first sealant was injected while the dispensing nozzle for the first sealant was scanned in one direction along the periphery of the element substrate. Other than these, the method was the same as Example 1. In the liquid ejection head obtained by the method of Example 3, the height of the surface of the first sealant around the periphery of the element substrate was 0.10 mm above the top surface of the element substrate, which was within an appropriate range.

[0038] Example 4 In Example 4, a sealant with a viscosity of 3 Pa s was used as the first sealant. Other than this, the procedure was the same as in Example 1. In the liquid ejection head obtained by the method of Example 4, the height of the surface of the first sealant around the periphery of the element substrate was 0.10 mm above the upper surface of the element substrate, which was within an appropriate range.

[0039] (Comparative Example) In the comparative example, no sealant detection groove was provided. The injection of the first sealant was stopped at any timing. Other than these, the procedure was the same as in Example 1. In the liquid ejection head obtained by the method of the comparative example, the height of the surface of the first sealant around the element substrate was 0.30 mm from the top surface of the element substrate. Because the height of the surface of the first sealant was too low (the amount of first sealant was insufficient), additional first sealant was injected, and as a result, the height of the surface of the first sealant became higher than the top surface of the element substrate. Specifically, the first sealant overflowed from the space between the element substrate and the cover and entered the ejection port, making it impossible to eject liquid. [Explanation of symbols]

[0040] 1: Liquid ejection head 2: Element substrate 5: Wiring substrate 6: Support member 7: Cover 8: First sealant 11: Sealant detection groove

Claims

1. a support member having a substrate mounting surface; an element substrate provided on the substrate mounting surface and having a discharge port for discharging a liquid; a wiring board provided on the board installation surface, electrically connected to the element board, and lower in height from the board installation surface than the element board; and a cover provided on the substrate mounting surface so as to surround the periphery of the element substrate and cover the wiring substrate when the substrate mounting surface is viewed from a direction perpendicular to the substrate mounting surface; providing a structure having: injecting a sealant into a gap between the element substrate and the cover; and a recessed portion is formed in the element substrate, the recessed portion spanning an exposed surface exposed from the cover and an end surface; The flow of the sealant into the recess is detected, and the injection of the sealant is terminated. A method for manufacturing a liquid ejection head, comprising:

2. The height of the surface of the cover opposite to the surface facing the substrate mounting surface is higher than the height of the element substrate from the substrate mounting surface. The method for manufacturing a liquid ejection head according to claim 1 .

3. When the substrate mounting surface is viewed from a direction perpendicular to the substrate mounting surface, the sealant is injected at a position near a point symmetrical to the recess with respect to the center of the element substrate. The method for manufacturing a liquid ejection head according to claim 1 or 2.

4. The sealant is injected while moving the injection position along the periphery of the element substrate, with the injection position being set to an end point near the position of the recess when the substrate mounting surface is viewed in a direction perpendicular to the substrate mounting surface. The method for manufacturing a liquid ejection head according to claim 1 or 2.

5. a plurality of recesses are formed in the element substrate, The flow of the sealant into the recesses is detected, and the injection of the sealant is terminated. The method for manufacturing a liquid ejection head according to claim 1 or 2.

6. a plurality of recesses are formed in the element substrate, the plurality of recesses have different depths from the exposed surface, The flow of the sealant into at least one of the recesses is detected, and the injection of the sealant is terminated. The method for manufacturing a liquid ejection head according to claim 1 or 2.

7. the recess includes a first bottom surface adjacent to the end surface and a second bottom surface adjacent to the first bottom surface and shallower than the first bottom surface; and detecting that the sealant has flowed into the recess beyond at least the first bottom surface, and then terminating the injection of the sealant. The method for manufacturing a liquid ejection head according to any one of claims 1 to 4.

8. The depth of the recess from the exposed surface is 0.2 mm or less. The method for manufacturing a liquid ejection head according to any one of claims 1 to 7.

9. a support member having a substrate mounting surface; an element substrate provided on the substrate mounting surface and having a discharge port for discharging a liquid; a wiring board provided on the board installation surface, electrically connected to the element board, and lower in height from the board installation surface than the element board; a cover provided on the substrate mounting surface so as to surround the periphery of the element substrate and cover the wiring substrate when the substrate mounting surface is viewed in a direction perpendicular to the substrate mounting surface; a sealant that fills the gap between the element substrate and the cover; and a recessed portion is formed in the element substrate, the recessed portion spanning an exposed surface exposed from the cover and an end surface; The sealant is filled up to the position of the recess. A liquid ejection head characterized by:

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