Liquid ejection head and manufacturing method thereof

Abstract

A liquid ejection head is provided that is equipped with a damper portion that has high damping performance and high durability. [Solution] A liquid ejection head comprising a plurality of ejection ports for ejecting liquid, a plurality of pressure chambers each connected to the plurality of ejection ports, a plurality of pressure generating means provided in each of the plurality of pressure chambers for generating pressure for ejecting liquid from the ejection ports, a common flow path connected to all of the pressure chambers, a flexible member that forms part of the wall of the common flow path and is deformable in response to pressure fluctuations generated in the plurality of pressure chambers, and a hollow damper chamber arranged in a position opposite the common flow path via the flexible member, wherein the breaking strength of the flexible member at the periphery of the damper chamber is higher than the breaking strength at the center of the damper chamber.

Description

[Technical Field]

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

[0002] Some liquid ejection heads that eject ink are configured to eject ink droplets from ejection ports by applying pressure to ink in a pressure chamber using a drive unit.

[0003] When pressure fluctuations occur due to the ejection of ink droplets, these pressure fluctuations may propagate to other pressure chambers via a flow path shared by multiple ejection ports, which may result in ejection failure due to so-called crosstalk.

[0004] In response to this, Patent Document 1 discloses a configuration in which a damper chamber is provided adjacent to the supply / return circulation flow path, and a flexible partition wall is provided between this flow path and the damper chamber. With this configuration, the partition wall deforms, making it possible to suppress pressure fluctuations of the ink inside the flow path. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-9224 Summary of the Invention [Problem to be solved by the invention]

[0006] The partition wall described in Patent Document 1 is required to have high durability as well as flexibility to function as a damper. However, if flexibility is prioritized, the fixed portion of the partition wall is likely to peel off when the partition wall is deformed. On the other hand, if robustness of the fixed portion is prioritized, there is a risk that the damping performance will be reduced. In other words, with the configuration disclosed in Patent Document 1, it was sometimes difficult to achieve both high damping performance and high durability.

[0007] An object of the present disclosure is to provide a liquid ejection head equipped with a damper portion that has high damping performance and high durability. [Means for solving the problem]

[0008] According to the present invention, a liquid ejection head is provided which comprises a plurality of ejection ports for ejecting liquid, a plurality of pressure chambers each connected to the plurality of ejection ports, a plurality of pressure generating means provided in each of the plurality of pressure chambers for generating pressure for ejecting liquid from the ejection ports, a common flow path which is connected to all of the pressure chambers, a flexible member which forms part of the wall surface of the common flow path and is deformable in response to pressure fluctuations generated in the plurality of pressure chambers, and a hollow damper chamber which is arranged in a position opposite the common flow path via the flexible member, wherein the breaking strength of the flexible member at the peripheral portion of the damper chamber is higher than the breaking strength at the center of the damper chamber. [Effects of the Invention]

[0009] According to the present invention, high damping performance and high durability of the flexible member are possible. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view of a liquid ejection head according to the present disclosure. [Figure 2] 1A and 1B are a top view and a cross-sectional view illustrating the structure of a typical damper portion. [Figure 3] 1A and 1B are a top view and a cross-sectional view of a damper portion according to a first embodiment of the present invention. [Figure 4] FIG. 6 is a schematic cross-sectional view of a damper portion according to a second embodiment of the present disclosure. [Figure 5] FIG. 10 is a schematic cross-sectional view showing a modified example of the damper portion according to the second embodiment of the present disclosure. [Figure 6] 10A and 10B are a top view and a cross-sectional view showing a damper portion according to a third embodiment of the present disclosure. [Figure 7] FIG. 10 is a schematic cross-sectional view showing a damper portion according to a fourth embodiment of the present disclosure. [Figure 8] 10A and 10B are a top view and a cross-sectional view showing a damper portion according to a fifth embodiment of the present disclosure. [Figure 9] 5A to 5C are diagrams illustrating a method for manufacturing the damper portion according to the first embodiment. [Figure 10] 10A to 10C are diagrams illustrating a method for manufacturing a damper portion according to a second embodiment. [Figure 11] 10A to 10C are diagrams illustrating a manufacturing method of a modified example of the damper portion according to the second embodiment. [Figure 12] 10A to 10C are diagrams illustrating a method for manufacturing a damper portion according to a third embodiment. [Figure 13] 10A to 10C are diagrams illustrating a method for manufacturing a damper portion according to a fourth embodiment. [Figure 14] 10A to 10C are diagrams illustrating a method for manufacturing a damper portion according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] The configuration, operation, and effects of the liquid ejection head according to the present invention will be described below by taking preferred embodiments as examples. Specific expressions may be used to fully explain the present invention, but they are not intended to limit the scope of the present invention.

[0012] (Liquid discharge device) 1 is a schematic cross-sectional view of a liquid ejection head 1000 of the present invention. In the figure, the X direction is the direction in which the ejection ports are arranged and corresponds to the longitudinal direction of the liquid ejection head. The Y direction is the direction in which the ejection port rows are arranged and corresponds to the width direction of the liquid ejection head. The Z direction is the liquid ejection direction.

[0013] The liquid ejection head 1000 includes a first flow path member 1, a second flow path member 2, a third flow path member 3, and a fourth flow path member 4. A flexible member 5 is provided between the first flow path member 1 and the second flow path member 2. A first flow path 10 is provided through the first flow path member 1 and the flexible member 5. The second flow path member 2 is provided with a common liquid chamber 210 (common flow path) communicating with the first flow path 10, a second flow path 20, and an accommodation space 200 accommodating a piezoelectric element 301. The third flow path member 3 is provided with a third flow path 30 communicating with the second flow path 20. The third flow path member 3 includes wiring for driving the piezoelectric element 301, etc. The fourth flow path member 4 is provided with a pressure chamber 300 and an ejection port 40 for ejecting ink. The pressure chamber 300 and the piezoelectric element 301 are provided at positions corresponding to the ejection port 40, and ink is ejected from the ejection port 40 by driving the piezoelectric element 301.

[0014] The liquid ejection head 1000 of this embodiment is an ink circulation type liquid ejection head. Liquid flows from the first flow path 10 into the common liquid supply chamber 210, passes through the second and third flow paths 20 and 30, and is transported to the pressure chambers 300 of the fourth flow path member 4. The liquid is then ejected from the ejection ports 40 by driving the piezoelectric elements 301. Liquid that is not ejected passes through the third and second recovery flow paths 30 and 20, is transported to the common recovery liquid chamber 210, and is discharged to the outside through the first recovery flow path 10. A plurality of ejection ports 40 are arranged in the X direction, and each ejection port 40 is associated with one piezoelectric element 301 and one pressure chamber 300. In the liquid ejection head 1000 of this embodiment, two such ejection port arrays are arranged in the Y direction. The common liquid chamber 210 is provided to be in common communication with the plurality of ejection ports 40 and pressure chambers 300 arranged in the X direction. In this embodiment, the common liquid supply chamber 210 is provided for each ejection port array, and the common liquid recovery chamber 210 is provided so as to be shared by two ejection port arrays.

[0015] When the piezoelectric element 301 is driven, a pressure wave is generated around the piezoelectric element 301. This pressure wave propagates through the third flow path 30 and the second flow path 20, which are connected to the pressure chamber 300, to the common liquid chamber 210, which is located directly above the second flow path 20. At this time, the flexible member 5, which forms part of the wall surface of the common liquid chamber 210, is pushed toward the damper chamber 100 by the pressure wave and deforms, thereby attenuating the pressure wave. Hereinafter, in this disclosure, the pair of damper chambers 100 and the flexible member 5 will be collectively referred to as a damper section. One damper section collectively receives pressure waves generated in multiple pressure chambers 300.

[0016] The flexible member 5 mounted on conventional liquid ejection heads is often formed of a uniform material and a uniform thickness. In this case, the thinner the flexible member 5, the greater the amount of deformation when pressure is transmitted to the flexible member 5, and therefore the greater the expected pressure fluctuation suppression effect. However, because the flexible member 5 repeatedly deforms over a long period of time, the parts in contact with the corners of the damper chamber 100 wear and become more susceptible to tearing. If the flexible member 5 tears, not only does the pressure fluctuation suppression effect decrease, but liquid inside the flow path also enters the damper chamber 100, causing unstable ejection performance. On the other hand, if the thickness of the flexible member 5 is increased to reduce the risk of tearing over long periods of use, the amount of deformation when pressure is transmitted to the flexible member decreases, resulting in a reduced pressure fluctuation suppression effect. Thus, achieving a consistent level of pressure fluctuation suppression while maintaining high durability of the flexible member is a challenge.

[0017] 2(a) to 2(c) are enlarged schematic diagrams showing a conventional general damper section. Fig. 2(a) is a top view of the first flow path member 1 of the portion corresponding to the damper section, Fig. 2(b) is a cross-sectional view taken along line IIb-IIb in Fig. 2(a), and Fig. 2(c) is a cross-sectional view taken along line IIc-IIc in Fig. 2(c).

[0018] The flexible member 5 formed between the first flow path member 1 and the second flow path member 2 is preferably made of a photosensitive resin that cures through a chemical reaction. Such a member facilitates patterning and facilitates manufacturing of a liquid ejection head. Negative-type photosensitive resins are more preferable than positive-type photosensitive resins because they are more likely to have high chemical resistance. Materials that can be used for the flexible member 5 include epoxy, acrylic, urethane, silicone, benzocyclobutene, polyimide, polyamide, polyamideimide, cyanoacrylate, phenol, melamine, styrene, cyclized rubber, and mixtures thereof. Among these, resins primarily composed of epoxy, silicone, benzocyclobutene, or polyimide are preferred, as they have excellent chemical resistance. Silicones are not particularly limited, but condensation-type silicones and addition-type silicones can be used. Addition-type silicones, which exhibit minimal shrinkage upon cure, are particularly preferred. For example, epoxy-modified silicones, acrylic-modified silicones, methyl-based silicones, phenyl-based silicones, methylphenyl-based silicones, alkyd-modified silicones, polyester-modified silicones, and mixtures thereof can be used. The benzocyclobutene is not particularly limited, but the CYCLOTENE series manufactured by Dow Corp. can be used. The polyimide is not particularly limited, but a thermoplastic polyimide in the form of a film can be used, or a polyamic acid can be used as a precursor.

[0019] As shown in FIGS. 2(b) and 2(c), in the present disclosure, the area near the corner of the damper chamber 100 that comes into contact with the flexible member 5 is referred to as the peripheral portion 101 of the damper chamber, and the area further inward is referred to as the central portion 102. The flexible member 5 is pushed toward the damper chamber 100 (in the -Z direction) by pressure waves generated when the piezoelectric element 301 is driven. Because the flexible member 5 repeatedly undergoes this displacement motion, the portions located at the corners of the damper chamber 100 are more susceptible to wear than other portions. For this reason, there is a concern that the flexible member 5 at the peripheral portion 101 will wear down, causing cracks and leading to tearing.

[0020] Therefore, in the present disclosure, the breaking strength at the peripheral portion 101 of the damper chamber 100 is made higher than the breaking strength at the central portion 102 of the damper chamber 100. Thereby, the time until the flexible member 5 breaks can be extended, and the long life of the liquid ejection head can be realized. In order to make the breaking strength of the peripheral portion 101 of the damper chamber higher than that of the central portion 102, the conventional breaking strength can be maintained for the central portion 102. Therefore, appropriate flexibility, that is, high damping performance can be realized.

[0021] (First Embodiment) Figs. 3(a) to 3(c) are schematic views showing an enlarged damper portion of the present embodiment. Fig. 3(a) is a top view of the first flow path member 1 of a portion corresponding to the damper portion, Fig. 3(b) is a cross-sectional view taken along line IIIb-IIIb of Fig. 3(a), and Fig. 3(c) is a cross-sectional view taken along line IIIc-IIIc of Fig. 3(a).

[0022] In the present embodiment, by making the thickness of the flexible member 5 at the peripheral portion 101 thicker than that at the central portion 102, the breaking strength at the peripheral portion 101 of the damper chamber 100 is made higher than that at the central portion 102. Here, the "breaking strength" in the present disclosure indicates the strength defined in JIS K 6251.

[0023] The thicker the thickness of the flexible member 5, the higher the breaking strength, and it becomes possible to withstand the displacement operation repeatedly performed by the pressure wave. On the other hand, due to the thick film thickness, the flexible member 5 becomes difficult to deform and cannot sufficiently attenuate the pressure. Therefore, in the present embodiment, the film thickness is selectively formed between the peripheral portion 101 and the central portion 102.

[0024] In the flexible member 5 of the present embodiment, when the film thickness of the peripheral portion 101 is b and the film thickness of the central portion 102 is a, it is formed such that the relationship between these film thicknesses is a < b.

[0025] As a preliminary study, the inventors confirmed the displacement amount in the thickness direction of the flexible member 5 when the flexible member 5 is deformed by the pressure wave generated during the driving of the piezoelectric element. As a result, the displacement amount was 0.1 μm or less. In this case, if the peripheral portion 101 is 0.1 μm or more thicker than the film thickness of the central portion 102, the displacement amount of the central portion 102 can be suppressed within the range of the thickness of the entire flexible member 5, and the load applied to the peripheral portion 101 that abuts on the first flow path member 1 can be suppressed. Therefore, it becomes possible to realize a flexible member with higher durability than that formed with a uniform film thickness.

[0026] Further, the inventors confirmed that if the film thickness a of the flexible member in the central portion 102 is 2.0 μm or more, the vibration in the liquid chamber due to the pressure wave is sufficiently suppressed, there is no crosstalk, and the flexible member 5 does not break at the center of the damper chamber. Furthermore, it was confirmed that the film thickness b of the peripheral portion 101 of the flexible member can be formed up to a maximum of 35.0 μm. According to this, the film thickness a of the flexible member 5 is preferably in the range of 2.0 to 5.0 μm, and the film thickness b of the flexible member 5 is preferably in the range of 2.1 to 35.0 μm. Thereby, a damper portion having high damping performance and high durability can be realized. However, the above numerical values are merely examples. If the film thickness a of the flexible member in the central portion 102 and the film thickness of the peripheral portion 101 satisfy the relationship a < b, the breaking strength at the peripheral portion 101 becomes higher than that of the central portion 102, and high damping performance and high durability can be realized.

[0027] (Second Embodiment) FIG. 4 is a schematic cross-sectional view of a damper portion according to a second embodiment of the present disclosure. In this embodiment as well as in the first embodiment, the thickness at the peripheral edge portion 101 of the flexible member 5 is made thicker than that at the central portion 102. However, different from the first embodiment, three recesses are formed in the central portion 102 of the flexible member 5. When the average film thickness of the central portion 102 of the damper chamber 100 is a' and the average film thickness of the peripheral edge portion 101 of the damper chamber 100 is b', they are formed such that the relationship between these film thicknesses is a' < b'. Even with such a configuration, the breaking strength at the peripheral edge portion 101 of the damper chamber 100 can be made higher than that at the central portion 102 of the damper chamber 100, and a damper having high damping performance and high durability can be realized.

[0028] <Modification example> FIG. 5 is a schematic cross-sectional view showing a modification example of the damper portion according to the second embodiment.

[0029] As shown in FIG. 5, the film thickness of the peripheral edge portion 101 of the damper chamber 100 is not made uniform, and in the portion of the peripheral edge portion 101 that does not contact the first flow path member 1, the thickness is tapered and made thinner toward the central portion 102. Even with such a configuration, the relationship of a' < b' is satisfied, and the breaking strength at the peripheral edge portion 101 of the damper chamber 100 can be made higher than that at the central portion 102 of the damper chamber 100. As a result, a damper having high damping performance and high durability can be realized.

[0030] Note that, regarding the depth and width of the recess in FIG. 4, the angle of the taper and the region where the taper is provided in FIG. 5, it is possible to control the pressure suppression effect and the durability of the flexible member by arbitrarily adjusting them. That is, depending on whether the common liquid chamber 210 is for supply or recovery, the number of corresponding piezoelectric elements 301, the type of liquid, etc., the depth and width of the recess in FIG. 4, the angle of the taper and the region where the taper is provided in FIG. 5 may be made different.

[0031] In this embodiment, the average film thickness a' of the flexible member 5 is preferably in the range of 2.0 to 5.0 μm, and the average film thickness b' is preferably in the range of 2.1 to 35.0 μm. This makes it possible to realize a damper portion with high damping performance and high durability.

[0032] (Third embodiment) 6(a) to 6(c) are schematic diagrams showing a damper portion according to a third embodiment of the present disclosure.

[0033] As shown in FIGS. 6(b) and 6(c), the flexible member of this embodiment is composed of two different materials: a first flexible member 51 and a second flexible member 52. The peripheral portion 101 is formed from the first flexible member 51 and the second flexible member 52, and the central portion 102 is formed from the second flexible member 52. The second flexible member 52 has a uniform thickness throughout the damper section. This allows the rupture strength of the peripheral portion 101 of the damper chamber 100 to be higher than that of the central portion 102 of the damper chamber 100, thereby achieving high damping performance and durability. Appropriate materials can be selected for the first flexible member 51 and the second flexible member 52. However, it is preferable to select a material for the first flexible member 51 that has a higher rupture strength than that of the second flexible member 52.

[0034] Epoxy, acrylic, urethane, silicone, benzocyclobutene, polyimide, polyamide, polyamideimide, cyanoacrylate, phenol, melamine, styrene, cyclized rubber, or a mixture thereof can be used for first flexible member 51. Epoxy, acrylic, urethane, silicone, benzocyclobutene, polyimide, polyamide, polyamideimide, cyanoacrylate, phenol, melamine, styrene, cyclized rubber, or a mixture thereof can be used for second flexible member 52. Of these, resins primarily composed of epoxy, silicone, benzocyclobutene, or polyimide, which have excellent chemical resistance, are preferred for both first flexible member 51 and second flexible member 21.

[0035] The thicker the flexible member, the higher its breaking strength and the more it can withstand repeated displacement caused by pressure waves. On the other hand, a thick film makes the flexible member 51 difficult to deform, which may result in the flexible member 5 being unable to sufficiently attenuate pressure. Therefore, it is preferable to appropriately adjust the thicknesses of the first flexible member 51 and the second flexible member 21.

[0036] According to the inventors' investigations, it has been confirmed that, also in this embodiment, the film thickness a of the flexible member is preferably in the range of 2.0 to 5.0 μm, and the film thickness b is preferably in the range of 2.1 to 35.0 μm. By adjusting the thicknesses of the first flexible member 51 and the second flexible member 21 so as to achieve film thicknesses within these ranges, it is possible to realize a damper section with high damping performance and high durability.

[0037] In the above description, the flexible member 5 is made of two materials, the first flexible member 51 and the second flexible member 52, but it may be made of three or more materials.

[0038] (Fourth embodiment) FIG. 7 is a schematic cross-sectional view showing a damper portion according to the fourth embodiment of the present disclosure.

[0039] In this embodiment, as in the third embodiment, the flexible member includes a first flexible member 51 and a second flexible member 52. However, the first flexible member 51 according to the fourth embodiment is partially in contact with the inner wall of the damper chamber 100, as shown in FIG. 7. This increases the contact area between the first flexible member 51 and the first flow path member 1, and makes it possible to distribute the pressure applied to the contact portion with the first flow path member 1 when the flexible member 5 is displaced. This prevents the load from concentrating locally on the flexible member 5, suppresses wear on the surface of the flexible member due to repeated displacement operations, and extends the life of the damper section.

[0040] In this embodiment, the first flexible member 51 may also serve as an adhesive. In this case, the thickness (ba) of the first flexible member 51 is preferably in the range of 0.1 to 30.0 μm. The width of the thick portion of the peripheral edge portion 101 is preferably in the range of 0.1 to 20 μm. The adhesive that protrudes into the damper chamber during the bonding process between the pre-cured adhesive and the second flexible member 52 should ultimately form the first flexible member 51 with a width of 0.1 to 20 μm. With this configuration, the second flexible member 52 does not come into direct contact with the corners of the first flow path member 1 that form the damper chamber 100 during displacement of the flexible member, thereby reducing the risk of tearing the second flexible member 52.

[0041] (Fifth embodiment) 8(a) to 8(c) are schematic diagrams showing a damper portion according to a fifth embodiment of the present disclosure.

[0042] 8(b) and 8(c), the flexible member of this embodiment is formed of two materials in a planar direction perpendicular to the thickness direction: a third flexible member 54 disposed in a peripheral portion 101, and a fourth flexible member 55 disposed in a central portion 102. The breaking strength of the third flexible member 54 is set higher than that of the fourth flexible member 55. This makes the breaking strength of the peripheral portion 101 of the damper chamber 100 higher than that of the central portion 102 of the damper chamber 100, thereby achieving a damper section with high damping performance and high durability.

[0043] By selecting appropriate materials for the third flexible member 54 and the fourth flexible member 55, it is possible to further enhance the damping effect and durability. By selecting appropriate materials for the third flexible member 54 and the fourth flexible member 55 and adjusting the film thickness and the extent to which the third flexible member 54 protrudes into the damper chamber, it is possible to achieve both durability and damping performance of the flexible members. In the figure, the third flexible member 54 and the fourth flexible member 55 are shown to have the same film thickness, but if the film thickness of the third flexible member 54 is made larger than that of the fourth flexible member 55, higher damping performance and higher durability can be expected.

[0044] In the above description, the flexible member 5 is made of two materials, the third flexible member 54 and the fourth flexible member 55, but it may be made of three or more materials.

[0045] (Manufacturing method of the damper part) <Example of the first embodiment> In the liquid ejection head of the first embodiment, the first flow path member 1 was made of silicon, the second flow path member 2 was made of silicon, and the flexible member 5 was made of benzocyclobutene.

[0046] 9(a) to 9(e) are diagrams showing a method for manufacturing the damper portion according to the first embodiment. The damper portion is formed as a part of the liquid ejection head 1000 when manufacturing the liquid ejection head 1000. The steps shown in Fig. 9 show part of the manufacturing process of the liquid ejection head 1000, focusing on the damper portion.

[0047] However, the description with reference to Figures 9(a) to 9(e) is merely a technically preferred example, and the technical scope of the present disclosure is not particularly limited.

[0048] First, a 625 μm silicon substrate was prepared, and a positive resist was exposed to light and developed on both sides of the silicon substrate. After that, a first flow path member 1 having a recess that would become a damper chamber 100 was formed by dry etching, as shown in FIG. 9(a).

[0049] 9(b), the flexible member 5 before hardening and having a thickness of 2 μm was made into a dry film and transferred to the outer circumferential surface 12 of the first flow path member. In this example, benzocyclobutene, which is a thermosetting resin, was applied as the flexible member 5.

[0050] Next, benzocyclobutene was applied to a smooth support substrate 90 to a thickness of 3 μm. The support substrate 90 used here was made of silicon, similar to the first flow path member 1. Then, as shown in FIG. 9(c), the support substrate 90 and the first flow path member 1 were attached together with the surface coated with benzocyclobutene facing the uncured thermosetting resin, and bonded under pressure.

[0051] Next, the substrate was heated in an oven at 250°C. As a result, the material applied to the first flow path member 1 side and the material applied to the support substrate 90 side were bonded together as shown in Fig. 9(d), and a flexible member 5 was formed between the first flow path member 1 and the support substrate 90. Furthermore, as shown in Fig. 9(e), the support substrate 90 was completely removed by polishing and dry etching until the surface of the flexible member 5 was exposed.

[0052] <Example of the second embodiment> 10(a) to 10(f) are diagrams showing a method for manufacturing the damper portion shown in FIG. 4 according to the second embodiment.

[0053] The process up to attaching the material that will become part of the flexible member 5 to the first flow path member 1 is the same as that shown in Figures 9(a) and (b), and therefore a description thereof will be omitted here. Note that the description with reference to Figures 10(a) to (e) is merely a technically preferred example. In particular, the technical scope of the present disclosure is not limited thereto.

[0054] As shown in Fig. 10(a), similarly to the first embodiment, benzocyclobutene was applied to a support substrate 90 to a thickness of 3 µm. Thereafter, as shown in Fig. 10(b), patterning and dry etching were repeated multiple times to form an uneven shape in the benzocyclobutene layer.

[0055] 10(c), the surface coated with benzocyclobutene was placed facing the uncured thermosetting resin coated on the first flow path member 1. Then, as shown in FIG. 10(d), the support substrate 90 and the first flow path member 1 were attached to each other and bonded under pressure.

[0056] Next, the substrate was heated in an oven at 250°C. As a result, the material applied to the first flow path member 1 side and the material applied to the support substrate 90 side were bonded and hardened, as shown in Fig. 10(e). Furthermore, the support substrate 90 was completely removed by polishing and dry etching until the surface of the flexible member 5 was exposed, as shown in Fig. 10(f).

[0057] 11(a) to 11(e) are diagrams showing a method for manufacturing the damper portion of the second embodiment shown in Fig. 5. As with the damper portion shown in Fig. 5, a structure having a tapered shape on the surface of the flexible member 5 can also be formed by following the same processing procedure as described above.

[0058] <Example of the third embodiment> 12(a) to 12(d) are diagrams showing a method for manufacturing a damper portion according to the third embodiment.

[0059] However, the description with reference to Figures 12(a) to 12(d) is merely a technically preferred example, and the technical scope of the present disclosure is not particularly limited.

[0060] First, a 625 μm silicon substrate was prepared, and a positive resist was exposed to light and developed on both sides of the silicon substrate. After that, a first flow path member 1 having a recess that would become a damper chamber 100 was formed by dry etching, as shown in FIG. 12(a).

[0061] Next, as shown in FIG. 12(b), a 2 μm thick dry film of uncured adhesive was transferred to the outer circumferential surface of the first flow path member. In this example, a thermosetting resin made of a material other than benzocyclobutene was applied as the adhesive. This adhesive becomes the first flexible member 51.

[0062] Next, similarly to the first embodiment, a support substrate 90 was prepared by applying benzocyclobutene to a thickness of 3 μm. This benzocyclobutene layer became the second flexible member 52. Then, as shown in FIG. 12(c), the support substrate 90 was attached to the first flow path member 1 with the surface on which the benzocyclobutene was applied facing the uncured adhesive, and they were bonded while applying pressure.

[0063] Next, the first flexible member 51 and the second flexible member 52 were cured by heating in an oven at 250°C. Furthermore, the support substrate 90 was completely removed by polishing and dry etching until the surface of the flexible member 5 was exposed as shown in Fig. 12(d).

[0064] <Example of the fourth embodiment> 13(a) to 13(c) are diagrams showing a method for manufacturing a damper portion according to the fourth embodiment.

[0065] However, the description with reference to Figures 13(a) to 13(c) is merely a technically preferred example, and the technical scope of the present disclosure is not particularly limited.

[0066] 12(a) to 12(d), the manufacturing method is almost the same as that of the third embodiment described with reference to Fig. 12. However, in this embodiment, after the first flow path member 1 is formed by exposing and developing a positive resist on the first flow path member 1 and dry etching, the inner wall of the damper chamber 100 is subjected to plasma ashing to improve wettability.

[0067] 13(a), the support substrate 90 was brought into contact with the first flow path member 1 with the surface on which the second flexible member 52 was applied facing the uncured first flexible member 51. Furthermore, the two were bonded together while applying pressure, and the uncured first flexible member 51 was brought into contact with the inner wall of the damper chamber 100 as shown in FIG.

[0068] Next, the first flexible member 51 and the second flexible member 52 were cured by heating in an oven at 250° C. Furthermore, the support substrate 90 was completely removed by polishing and dry etching until the surface of the flexible member 5 was exposed, as shown in FIG.

[0069] When the damper portion was checked after hardening, it was found that first flexible member 51 had reached a height of 30 μm in the vertical direction from the interface with second flexible member 52.

[0070] <Example of the fifth embodiment> 14(a) to 14(e) are diagrams showing a method for manufacturing a damper portion according to the fifth embodiment.

[0071] However, the description with reference to Figures 14(a) to 14(e) is merely a technically preferred example, and the technical scope of the present disclosure is not particularly limited.

[0072] 12(a) and 12(b), the process up to attaching the material that will become part of the flexible member 5 to the first flow path member 1 will not be described here. In this example, the material applied to the first flow path member 1 becomes the third flexible member 54. In this example, a thermosetting resin was applied as the third flexible member 54.

[0073] 14(a), a support substrate 90 was prepared by applying a fourth flexible member 55. Here, the fourth flexible member 55 was made of benzocyclobutene and had a thickness of 3 μm.

[0074] 14(b), patterning and dry etching were performed to remove the outer peripheral region of fourth flexible member 55 until the surface of support substrate 90 was exposed. The size (width) of the outer peripheral region to be removed was set to a size that would prevent third flexible member 54 and fourth flexible member 55 from moving in the bonding direction (Z direction) in the bonding step described next.

[0075] Next, as shown in Fig. 14(c), the first flow path member coated with the third flexible member 54 and the support substrate 90 having the fourth flexible member 55 were placed opposite each other. These were then attached and bonded together under pressure. At this time, as shown in Fig. 14(d), the bonding pressure causes the third flexible member 54 to expand in the planar direction and come into contact with the side surface of the fourth flexible member 55.

[0076] Next, the third flexible member 54 and the fourth flexible member 55 were hardened by heating in an oven at 250°C. Furthermore, the support substrate 90 was completely removed by polishing and dry etching until the surface of the flexible member 5 was exposed, as shown in Fig. 14(e).

[0077] By fabricating the liquid ejection head as described above, it is possible to manufacture a liquid ejection head provided with a damper portion that is capable of high damping performance and high durability.

[0078] (Other embodiments) While the above description has been given taking a circulation-type liquid ejection head as illustrated in FIG. 1 as an example, the liquid ejection head of the present disclosure is not limited to this. A non-circulation-type liquid ejection head having a common liquid chamber and flow path for supply only may also be used. Furthermore, in the above embodiment, a piezoelectric element 301 is used to eject ink, but the present disclosure is not limited to this, and a heater that generates bubbles by film boiling may also be used.

[0079] Furthermore, the present disclosure includes configurations typified by the following liquid ejection head examples.

[0080] <Configuration 1> a plurality of discharge ports for discharging liquid; a plurality of pressure chambers respectively communicating with the plurality of ejection ports; a plurality of pressure generating means provided in the plurality of pressure chambers, respectively, for generating pressure for ejecting liquid from the ejection port; a common flow channel that is in communication with the plurality of pressure chambers; a flexible member that forms a part of a wall surface of the common flow channel and is deformable in response to pressure fluctuations occurring in the plurality of pressure chambers; a hollow damper chamber disposed at a position facing the common flow path with the flexible member interposed therebetween; A liquid ejection head comprising: The liquid ejection head is characterized in that the breaking strength of the flexible member at the periphery of the damper chamber is higher than the breaking strength at the center of the damper chamber.

[0081] <Configuration 2> 2. The liquid ejection head according to claim 1, wherein the flexible member has a thickness greater at the peripheral portion than at the central portion.

[0082] <Configuration 3> 2. The liquid ejection head according to configuration 1, wherein the thickness of the flexible member is not uniform at the peripheral portion or the central portion, and the average film thickness at the peripheral portion is greater than the average film thickness at the central portion.

[0083] <Configuration 4> 4. The liquid ejection head according to configuration 3, wherein the flexible member is tapered from the central portion toward the peripheral portion.

[0084] <Configuration 5> 4. The liquid ejection head according to configuration 3, wherein a recess is formed in the central portion of the flexible member.

[0085] <Configuration 6> 3. The liquid ejection head according to configuration 1 or 2, wherein the central portion of the flexible member is formed by a first flexible member, and the peripheral portion is formed by overlapping the first flexible member and a second flexible member.

[0086] <Configuration 7> 7. The liquid ejection head according to configuration 6, wherein the first flexible member has a breaking strength higher than the breaking strength of the second flexible member.

[0087] <Configuration 8> 7. The liquid ejection head according to configuration 6, wherein the first flexible member is in contact with a portion of the inner wall of the damper chamber.

[0088] <Configuration 9> The liquid ejection head according to configuration 1, wherein the central portion is formed by a third flexible member, and the peripheral portion is formed by a fourth flexible member having a breaking strength higher than that of the third flexible member.

[0089] <Configuration 10> A liquid ejection head described in any one of configurations 1 to 9, wherein the flexible member is made of one of epoxy, acrylic, urethane, silicone, benzocyclobutene, polyimide, polyamide, polyamideimide, cyanoacrylate, phenol, melamine, styrene, and cyclized rubber, or a mixture of two or more thereof.

[0090] <Configuration 11> A method for manufacturing a damper portion for a liquid ejection head, comprising: a first application step of applying a first material to a peripheral portion of a flow path member having a recess, the peripheral portion surrounding the recess; a second coating step of coating a second material on the surface of the flat support substrate; a bonding step of bonding the first material and the second material together by placing the surface of the flow path member on which the first material is applied and the surface of the support substrate on which the second material is applied face to face; a curing step of curing the first material and the second material by heating; 10. A method for manufacturing a damper portion for a liquid ejection head, comprising:

[0091] <Configuration 12> 12. The method for manufacturing a damper portion for a liquid ejection head according to Configuration 11, further comprising a removing step of removing the support substrate after the hardening step.

[0092] <Configuration 13> 13. The method for manufacturing a damper portion for a liquid ejection head according to aspect 11 or 12, wherein the first material and the second material are the same material.

[0093] <Configuration 14> 13. The method for manufacturing a damper portion for a liquid ejection head according to aspect 11 or 12, wherein the first material and the second material are different materials.

[0094] <Configuration 15> 15. The method for manufacturing a damper portion for a liquid ejection head according to claim 14, wherein the first material has a breaking strength higher than the second material after hardening.

[0095] <Configuration 16> 16. The method of manufacturing a damper portion for a liquid ejection head according to any one of configurations 11 to 15, wherein after the second application step, a recess is formed on the surface to which the second material is applied.

[0096] <Configuration 17> 17. The method for manufacturing a damper portion for a liquid ejection head according to any one of configurations 11 to 16, wherein a part of the first material before hardening moves to the inside of the recess in the bonding step.

[0097] <Configuration 18> the method further includes, after the second application step, removing from the support substrate a region of the second material applied to the support substrate that corresponds to the peripheral edge portion, 13. The method for manufacturing a liquid ejection head according to configuration 11 or 12, wherein in the bonding step, the first material and the second material are bonded in a direction intersecting a direction in which the flow path member and the support substrate face each other.

[0098] <Configuration 19> 19. The method for manufacturing a damper portion for a liquid ejection head according to claim 11, wherein the flow path member is made of silicon.

[0099] <Configuration 20> A method for manufacturing a damper portion for a liquid ejection head described in any one of configurations 11 to 19, wherein the first material and the second material are each one of epoxy, acrylic, urethane, silicone, benzocyclobutene, polyimide, polyamide, polyamideimide, cyanoacrylate, phenol, melamine, styrene, and cyclized rubber, or a mixture of two or more thereof. [Explanation of symbols]

[0100] 5 Flexible member 40 outlet 100 damper chamber 101 Damper chamber periphery 102 Damper room center 210 common liquid chamber 300 pressure chamber 301 Piezoelectric element

Claims

1. a plurality of discharge ports for discharging liquid; a plurality of pressure chambers respectively communicating with the plurality of ejection ports; a plurality of pressure generating means provided in the plurality of pressure chambers, respectively, for generating pressure for ejecting liquid from the ejection port; a common flow channel that is in communication with the plurality of pressure chambers; a flexible member that forms a part of a wall surface of the common flow channel and is deformable in response to pressure fluctuations occurring in the plurality of pressure chambers; a hollow damper chamber disposed at a position facing the common flow path with the flexible member interposed therebetween; A liquid ejection head comprising: The liquid ejection head is characterized in that the breaking strength of the flexible member at the periphery of the damper chamber is higher than the breaking strength at the center of the damper chamber.

2. 2. The liquid ejection head according to claim 1, wherein the flexible member has a thickness greater at the peripheral edge than at the central portion.

3. 2. The liquid ejection head according to claim 1, wherein the thickness of the flexible member is not uniform at the peripheral portion or the central portion, and the average film thickness at the peripheral portion is greater than the average film thickness at the central portion.

4. 4. The liquid ejection head according to claim 3, wherein the flexible member is tapered from the central portion toward the peripheral edge portion.

5. 4. The liquid ejection head according to claim 3, wherein a recess is formed in the central portion of the flexible member.

6. 2. The liquid ejection head according to claim 1, wherein the central portion of the flexible member is formed by a first flexible member, and the peripheral portion is formed by overlapping the first flexible member and a second flexible member.

7. The liquid ejection head according to claim 6 , wherein the first flexible member has a breaking strength higher than that of the second flexible member.

8. The liquid ejection head according to claim 6 , wherein the first flexible member is in contact with a portion of an inner wall of the damper chamber.

9. 2. The liquid ejection head according to claim 1, wherein the central portion is formed by a third flexible member, and the peripheral portion is formed by a fourth flexible member having a breaking strength higher than that of the third flexible member.

10. 2. A liquid ejection head according to claim 1, wherein the flexible member is made of any one of epoxy, acrylic, urethane, silicone, benzocyclobutene, polyimide, polyamide, polyamideimide, cyanoacrylate, phenol, melamine, styrene, and cyclized rubber, or a mixture of two or more thereof.

11. A method for manufacturing a damper portion for a liquid ejection head, comprising: a first application step of applying a first material to a peripheral portion of a flow path member having a recess, the peripheral portion surrounding the recess; a second coating step of coating a second material on the surface of the flat support substrate; a bonding step of bonding the first material and the second material together by placing a surface of the flow path member on which the first material is applied and a surface of the support substrate on which the second material is applied face to face; a curing step of curing the first material and the second material by heating; 10. A method for manufacturing a damper portion for a liquid ejection head, comprising:

12. The method for manufacturing a damper portion for a liquid ejection head according to claim 11, further comprising a removing step of removing the support substrate after the hardening step.

13. The method for manufacturing a damper portion for a liquid ejection head according to claim 11, wherein the first material and the second material are the same material.

14. The method for manufacturing a damper portion for a liquid ejection head according to claim 11, wherein the first material and the second material are different materials.

15. The method for manufacturing a damper portion for a liquid ejection head according to claim 14, wherein the first material has a breaking strength after hardening that is higher than the breaking strength of the second material after hardening.

16. The method for manufacturing a damper portion for a liquid ejection head according to claim 11, wherein after the second application step, a recess is formed on the surface to which the second material is applied.

17. The method for manufacturing a damper portion for a liquid ejection head according to claim 11, wherein a part of the first material before hardening moves to the inside of the recess in the bonding step.

18. the method further includes, after the second application step, removing from the support substrate a region of the second material applied to the support substrate that corresponds to the peripheral edge portion, The method for manufacturing a damper portion for a liquid ejection head according to claim 11 , wherein in the bonding step, the first material and the second material are bonded in a direction intersecting a direction in which the flow path member and the support substrate face each other.

19. The method for manufacturing a damper portion for a liquid ejection head according to claim 11, wherein the flow path member is made of silicon.

20. 12. A method for manufacturing a damper portion for a liquid ejection head as described in claim 11, wherein the first material and the second material are each one of epoxy, acrylic, urethane, silicone, benzocyclobutene, polyimide, polyamide, polyamideimide, cyanoacrylate, phenol, melamine, styrene, and cyclized rubber, or a mixture of two or more thereof.

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