Liquid discharge head, and method for manufacturing liquid discharge head

Abstract

To provide a liquid discharge head which suppresses deterioration of discharge controllability.SOLUTION: A liquid discharge head used in a liquid discharge head discharging liquid includes a nozzle discharging liquid, pressure generation means for generating pressure for discharging the liquid from the nozzle, a pressure chamber where the pressure generation means is formed, a liquid flow channel communicating with the nozzle, a space 7 formed adjacent to the liquid flow channel so as to be separated from the liquid flow channel, a base 51 constituting a wall part forming the liquid flow channel and a wall part forming the space 7, and a flexible member 6 which is fixed to the base 51, is deflected according to pressure fluctuation generated in the pressure chamber across the space 7 between the liquid flow channel and the flexible member 6 and is made of a resin. An inorganic film 5 is provided on the surface of the flexible member 6.SELECTED DRAWING: Figure 10

Description

Technical Field

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

Background Art

[0002] In a liquid ejection head that generates pressure fluctuations in a pressure generation chamber filled with a liquid and ejects the liquid from a nozzle, in order to avoid the pressure fluctuations from propagating to another adjacent pressure generation chamber and deteriorating the ejection controllability, a head configuration is known in which a unit member that suppresses pressure fluctuations, called a damper, is disposed in a liquid flow path. Patent Document 1 discloses a configuration in which, in a configuration where a damper is joined to a substrate using an adhesive, a member is disposed at the joint portion to prevent the protruding adhesive from adhering to the damper and to suppress variations in the fluctuation suppression effect.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When joining a damper to a substrate using an adhesive, heat treatment is required to cure the adhesive. During this heat treatment, due to the difference in linear expansion between the damper and peripheral members such as the substrate, the damper may bend (warp) toward the adjacent fluctuation suppression space side. When the damper is joined to the substrate in a bent state, the amount of deformation of the damper is limited when pressure fluctuations occur, so that the fluctuation suppression effect itself decreases, the damper performance is not fully exhibited, and the ejection controllability may deteriorate.

[0005] In order to solve the above problems, an object of the present invention is to provide a liquid ejection head that suppresses deterioration of ejection controllability.

Means for Solving the Problems

[0006] To achieve the above object, the liquid ejection head of the present invention is a liquid ejection head that ejects liquid, a nozzle through which the liquid is ejected, and pressure generating means for generating a pressure for ejecting the liquid from the nozzle, a pressure chamber formed inside the pressure generating means, a liquid flow path communicating with the nozzle, a space formed adjacent to the liquid flow path and separated from the liquid flow path, a base body constituting a wall portion forming the liquid flow path and a wall portion forming the space, a resin-made flexible member fixed to the base body, separating the liquid flow path and the space, and deflecting in response to pressure fluctuations generated in the pressure chamber, and an inorganic film is provided on the surface of the flexible member. Further, to achieve the above object, a method for manufacturing a liquid ejection head of the present invention is a method for manufacturing a liquid ejection head including a nozzle through which liquid is ejected, pressure generating means for generating a pressure for ejecting the liquid from the nozzle, a pressure chamber formed inside the pressure generating means, a liquid flow path communicating with the nozzle, a space formed adjacent to the liquid flow path and separated from the liquid flow path, a base body constituting a wall portion forming the liquid flow path and a wall portion forming the space, a resin-made flexible member fixed to the base body, separating the liquid flow path and the space, and deflecting in response to pressure fluctuations generated in the pressure chamber, and an inorganic film provided on the surface of the flexible member comprising: a step of applying an adhesive to the surface of the base body, a step of attaching the flexible member to the surface of the base body to which the adhesive has been applied, a step of heat-treating the adhesive to cure it, a step of forming the inorganic film on the surface of the flexible member, and is characterized by including these steps.

Advantages of the Invention

[0007] According to the present invention, a liquid ejection head capable of suppressing deterioration of ejection controllability can be provided.

Brief Description of the Drawings

[0008]

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Embodiments for Carrying Out the Invention

[0009] Hereinafter, with reference to the drawings, embodiments for carrying out the present invention will be exemplarily and in detail described based on examples. Note that the dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions. That is, the scope of the present invention is not intended to be limited to the following embodiments.

[0010] FIG. 18 is a schematic perspective view for explaining an example of a liquid ejection head to which the present disclosure is applicable. The liquid ejection head 100 has a plurality of substrates 1 for a liquid ejection head having nozzles 2 disposed in a liquid ejection head main body 100a. The ink to be ejected is supplied from a liquid tank (not shown) to the substrate 1 for a liquid ejection head through a common supply port (not shown) of the liquid ejection head main body 100a.

[0011] The configuration of the substrate for a liquid ejection head of the present invention and its manufacturing method will be described with reference to FIG. 1. FIG. 1 is a schematic cross-sectional view of a substrate for a liquid ejection head. Generally, the substrate 1 for a liquid ejection head constitutes a part of the liquid ejection head and mainly has a function of distributing the liquid supplied from the outside to each individual nozzle and ejecting the liquid from a plurality of nozzles (not shown). The substrate 1 for a liquid ejection head to which the present invention is applied has nozzles 2 for ejecting liquid and liquid flow paths 11 connected to the nozzles 2. FIG. 1 shows a cross-section of a region where two nozzles 2 are disposed as a cross-section of the substrate 1 for a liquid ejection head.

[0012] The liquid flow path 11 is composed of elements such as a pressure chamber 3 equipped with a pressure generating means 4, individual supply ports 8, a common flow path 9, a liquid supply port 10, etc. Its arrangement location, dimensions, and path can take various configurations according to the manufacturing method and the required discharge performance. For example, it is also possible to have a path of the liquid flow path such that the liquid supplied from the outside of the substrate for the liquid discharge head is transported to near the nozzle and the liquid that has not been discharged returns to the outside again. A flexible member 6 for suppressing pressure fluctuations is formed together with the adjacent space 7 in the middle of the liquid flow path 11.

[0013] As the pressure generating means 4, for example, a diaphragm formed by laminating piezoelectric elements, a heating resistor, etc. can be used. The pressure generating means 4 is formed in the pressure chamber 3 and generates the pressure for discharging a liquid such as ink from the nozzle 2.

[0014] The individual supply ports 8 are connected to the individually controlled pressure chambers 3, but a configuration in which a plurality of individual supply ports 8 are connected to one pressure chamber 3 or, conversely, a configuration in which one individual supply port 8 is connected to a plurality of pressure chambers 3 may also be possible.

[0015] The common flow path 9 is connected to a plurality of individual supply ports 8 and functions as a reservoir for distributing the liquid.

[0016] The flexible member 6 is provided in the middle of the liquid flow path 11, forms a part of the side wall of the liquid flow path 11, and is formed to be in contact with the liquid. A space 7 serving as a space for displacement is adjacent to the flexible member 6, and no liquid flows into here. The flexible member 6 bends at parts other than the fixed part according to the pressure fluctuations generated in the pressure chamber 3. The flexible member 6 is a member for absorbing the pressure fluctuations generated in the pressure chamber 3 by its flexibility, suppressing the pressure propagation to the nearby pressure chambers 3, and stabilizing the discharge performance. It is also possible to provide a configuration in which an air communication port is provided in the space 7 so that the inside is in a vacuum state and the displacement of the flexible member 6 is not restricted.

[0017] The flexible member 6 can be applied with films made of various flexible materials such as organic films, inorganic films, and metal films. Preferably, an organic resin film having both flexibility and resistance to liquids is used. Examples of the organic resin film applicable to the flexible member 6 include polyimide, polyamide, and polyphenylene sulfide. The thickness of the flexible member 6 may be appropriately set with reference to the elastic modulus in consideration of the viscosity and density of the liquid for suppressing pressure fluctuations, the liquid ejection frequency, the distance from the pressure chamber 3, and the like. Generally, in the application of the liquid ejection head substrate 1, the thickness of the flexible member 6 is formed in the range of from submicrons to about several tens of microns.

[0018] Referring to FIG. 2, a method for manufacturing the liquid ejection head substrate 1 will be described. FIG. 2 is an exploded perspective view of the liquid ejection head substrate 1. As shown in FIG. 2, the liquid ejection head substrate 1 is manufactured by bonding a plurality of substrates via an adhesive. The substrates constituting the liquid ejection head substrate 1 include, for example, a nozzle substrate 20, a pressure generating substrate 30, a flow path substrate 40, and a compliance substrate 50. FIG. 2 shows the liquid ejection head substrate 1 having the nozzle substrate 20, the pressure generating substrate 30, the flow path substrate 40, and the compliance substrate 50 in this order, that is, the liquid ejection head substrate 1 configured by arranging these substrates in this order. Unless otherwise specified, the liquid ejection head substrate 1 in each of the embodiments and examples described below has such a configuration.

[0019] Next, the configuration and manufacturing method of the compliance substrate 50, which is a component of the liquid ejection head substrate 1, will be described separately for a comparative example and a plurality of embodiments according to the present invention. First, the comparative example will be described, and then the first to ninth embodiments will be described. In the description of the configuration of each embodiment, the same components as those in the previously described embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

[0020] <Comparative Example> With reference to FIGS. 3(a) to 3(d), a method for manufacturing the compliance substrate 50 according to the comparative example will be described. FIGS. 3(a) to 3(d) are explanatory diagrams of the method for manufacturing the compliance substrate 50 according to the comparative example. In FIGS. 3(a) to 3(d) and the figures described below, a state in which two spaces 7 and two liquid supply ports 10 are provided is shown, but the number and size of each component are not limited to those shown in the figures. The compliance substrate 50 is a composite substrate of a base substrate 51 processed with spaces 7, liquid supply ports 10, etc. and a flexible member 6. The flexible member 6 is attached to the base substrate 51 as a base and then fixed to manufacture it.

[0021] FIG. 3(a) shows a state in which a plurality of spaces 7 and liquid supply ports 10 are formed in the base substrate 51. For example, a silicon substrate is used for the base substrate 51. The spaces 7 and the liquid supply ports 10 are formed in the base substrate 51 by a processing method such as chemical processing like etching or laser processing on the base substrate 51. In other words, the base substrate 51 functions as a flow path forming member and a space forming member that constitute the liquid flow path 11 (common flow path 9 and liquid supply port 10) and the wall portion of the space 7. The space 7 is formed to open on the adhesion surface 51a of the base substrate 51 to which the adhesive 61 described later is applied. The adhesion surface 51a is a fixing surface for fixing the flexible member 6. The liquid supply port 10 is formed to penetrate from the adhesion surface 51a of the base substrate 51 to the surface opposite to the adhesion surface 51a.

[0022] FIG. 3(b) shows a state in which the adhesive 61 is applied on the base substrate 51. The adhesive 61 for fixing the flexible member 6 is applied to the adhesion surface 51a of the processed base substrate 51.

[0023] FIG. 3(c) shows a state in which the flexible member 6 is fixed on the base substrate 51. In the following description, the surface to be fixed (adhered surface) fixed to the adhesion surface 51a of the base substrate 51 of the flexible member 6 will be described as the first surface 6a, and the surface opposite to the first surface 6a will be described as the second surface 6b. In a state where the compliance substrate 50 is adhered to the flow path substrate 40 and the substrate 1 for the liquid ejection head is completed, the first surface 6a faces the space 7 side, and the second surface 6b faces the common flow path 9 side (liquid flow path 11 side).

[0024] After the adhesive 61 is applied to the base substrate 51, next, the film-like flexible member 6 is attached onto the base substrate 51 by roller pressing or the like. Thereafter, heat treatment (curing) is performed to cure the adhesive 61 and fix the flexible member 6 to the base substrate 51. The temperature of the heat treatment varies depending on the material of the adhesive and the heat-resistant temperature of the flexible member 6. For example, heating at several hundred degrees promotes the polymerization reaction between the adhesive molecules to cure them. After the fixing step of the flexible member 6, the space 7 becomes a space surrounded and closed by the flexible member 6 and the base substrate 51. Also, the opening on the adhesive surface 51a side of the liquid supply port 10 is closed by the flexible member 6.

[0025] FIG. 3(d) shows a state in which an opening 6c is formed in the flexible member 6. After the flexible member 6 is fixed on the base substrate 51, an opening 6c serving as a passage for the liquid is formed in the flexible member 6. The opening 6c is formed at a position connected to the liquid supply port 10. That is, when viewed in a direction perpendicular to the adhesive surface 51a, the opening 6c is formed at a position overlapping the liquid supply port 10. For example, after a pattern is formed by photolithography, etching is performed to form the opening 6c.

[0026] In the compliance substrate 50 manufactured in this way, the flexible member 6 may be formed in a bent state so as to protrude toward the space 7 side. FIG. 3(c) shows a state in which the flexible member 6 fixed on the base substrate 51 is bent. The bending of the flexible member 6 mainly occurs during curing and is considered to be caused by internal stress due to the microscopic structure of each component and thermal stress due to the thermal expansion coefficient of each component. More specifically, it is considered that the difference in thermal expansion between the flexible member 6 and the base substrate 51 serving as the base is one of the causes. That is, when the flexible member 6 and the base substrate 51 thermally expand during curing and in that state, one side of the flexible member 6 is fixed to the base substrate 51, and then when cooled, a difference occurs in the amount of shrinkage between the surface of the flexible member 6 fixed to the base substrate 51 and the surface not fixed. Then, stress is generated in the flexible member 6, and it is considered that the stress is one of the causes of the bending. It is considered that the difference in thermal expansion between the flexible member 6 and the base substrate 51 serving as the base is one of the causes. That is, when the flexible member 6 and the base substrate 51 thermally expand during curing and in that state, one side of the flexible member 6 is fixed to the base substrate 51, and then when cooled, a difference occurs in the amount of shrinkage between the surface of the flexible member 6 fixed to the base substrate 51 and the surface not fixed. Then, stress is generated in the flexible member 6, and it is considered that the stress is one of the causes of the bending.

[0027] In a laminate of dissimilar materials having different coefficients of thermal expansion, generally, a stress that causes warping occurs such that the side of the material with the smaller coefficient of thermal expansion bulges. Therefore, for example, when a silicon substrate is used as the base substrate 51 and an organic resin is used as the flexible member 6, generally, the coefficient of thermal expansion of the flexible member > the coefficient of thermal expansion of the silicon substrate. In such a case, the flexible member 6 warps and bends so as to bulge toward the space 7 side. When the liquid ejection head substrate 1 is manufactured in such a warped state of the flexible member 6, the displacement of the flexible member 6 toward the space 7 side is restricted when absorbing pressure fluctuations, and the suppression function is also restricted. Therefore, in the configuration of the comparative example, when pressure fluctuations occur in the common flow path 9 in the pressure generation chamber, the pressure fluctuations may propagate to another common flow path 9 or the like, and the ejection controllability of the liquid ejection head substrate 1 may deteriorate.

[0028] <First Embodiment> Next, with reference to FIGS. 4(a) to (e), the compliance substrate 50 according to the first embodiment will be described. FIGS. 4(a) to (e) are explanatory views of a manufacturing method of the compliance substrate 50 according to the first embodiment. In the first embodiment, the surface member 5 is formed on the flexible member 6 of the compliance substrate 50. Any material such as an organic material, an inorganic material, or a metal material can be applied to the surface member 5. However, in the case of a material such as an inorganic material that may inhibit the flexibility of the flexible member 6 depending on its thickness, it is preferable to make a thin film that does not interfere with the flexibility by making the film thickness as thin as possible within a range where the bending can be relaxed, preferably on the order of submicrons. The configuration disclosed in Japanese Patent No. 7131260 is a configuration in which a thick member having no flexibility (or very little flexibility) is laminated to prevent the adhesive from protruding from the flexible film. It is a configuration fundamentally different from the liquid ejection head substrate 1 according to the first embodiment, which has a film-like member that moves following the flexible member.

[0029] Figs. 4(a) to (e) show a method for manufacturing the compliance substrate 50 according to the first embodiment. Fig. 4(a) shows a state where the space 7 and the liquid supply port 10 are formed in the base substrate 51. Fig. 4(b) shows a state where the adhesive 61 is applied on the base substrate 51. Fig. 4(c) shows a state where the flexible member 6 is fixed on the base substrate 51. Fig. 4(d) shows a state where the opening 6c is formed in the flexible member 6. The manufacturing processes shown in these figures are the same processes as Figs. 3(a) to (d) according to the comparative example. As shown in Fig. 4(c) and Fig. 4(d), after the fixing process of the flexible member 6 to the base substrate 51 and before the forming process of the surface member 5 described later, the flexible member 6 is fixed to the base substrate 51 in a state of being bent toward the space 7 side.

[0030] Fig. 4(e) shows a state where the surface member 5 is formed on the surface of the flexible member 6. The surface member 5 is a film-like member that reduces the deflection of the flexible member 6 so as to generate a stress that causes the surface member 5 to warp in the direction opposite to the deflection of the flexible member 6. In the first embodiment, the surface member 5 is formed on the surface of the flexible member 6 and on the inner peripheral surface of the liquid supply port 10 so as to cover the entire compliance substrate 50. More specifically, the surface member 5 is formed so as to cover the exposed surfaces of the base substrate 51 and the flexible member 6 in the compliance substrate 50. That is, the surface member 5 is not formed on the first surface 6a facing the space 7 side of the flexible member 6, but is formed on the second surface 6b opposite to the first surface 6a. By forming the surface member 5, the deflection that protrudes toward the space 7 side of the flexible member 6 in a state where the pressure generating means 4 is not generating pressure is reduced, and the flexible member 6 approaches a straight state. In this way, by reducing the deflection of the flexible member 6 in the unused state of the liquid ejection head substrate 1, a decrease in the pressure fluctuation absorption effect by the flexible member 6 is suppressed, and a deterioration in the ejection controllability of the liquid ejection head substrate 1 is suppressed.

[0031] In order to reduce (correct) the deflection of the flexible member 6 bent toward the space 7 in the first embodiment, a material having a smaller coefficient of thermal expansion than the flexible member 6 serving as a base is used for the surface member 5. Since the internal stress of the thin film varies depending on the composition and thickness, and also varies depending on the film formation conditions such as the film formation method and pressure, it is preferable to select the film formation method and film formation conditions of the surface member so as to obtain a stress in an appropriate direction. Generally, in the case of a metal thin film, it is known that sputtering method, ion plating method, etc. exhibit compressive stress, and evaporation, Chemical Vapor Deposition (CVD) method, etc. exhibit tensile stress.

[0032] As shown in FIG. 4(e), when forming the surface member 5 so as to cover the entire compliance substrate 50, a method such as Atomic Layer Deposition (ALD) can be used. For example, it is preferable to form an inorganic oxide thin film exhibiting compressive stress on the flexible member 6 serving as a base to a thickness of about several hundred nm by the ALD method. Further, it is preferable to use a material exhibiting flexibility such as an organic resin for the flexible member 6, and its coefficient of thermal expansion can generally be selected in the range from about several ppm to about several hundred ppm. Therefore, it is preferable that the surface member 5 be a material having a smaller coefficient of thermal expansion than the flexible member 6 serving as a base, for example, an inorganic thin film or the like, and a material having a coefficient of thermal expansion in the range from about several ppm to about several tens of ppm. In particular, when an organic resin is used for the flexible member 6, it is desirable to use an inorganic film for the surface member 5 from the viewpoint of the difference in the coefficient of thermal expansion.

[0033] As shown in Fig. 1, the flexible member 6 constitutes a part of the side wall of the liquid flow path 11. Therefore, since the surface member 5 is exposed to the side of the liquid flow path 11, it is preferable that the surface member 5 has resistance to liquids. By preventing the surface member 5 from easily dissolving, the deflection of the flexible member 6 can be suppressed over a long period. Also, in some cases, a protective film resistant to liquids may be required for the portion of the side wall of the liquid flow path 11 that is composed of members other than the flexible member 6. In such a case, by selecting a film-forming method capable of conformal film formation such as the ALD method or the CVD method, a protective film can be formed in a batch not only on the surface of the flexible member 6 but also on the surface of the liquid flow path 11 at the same time, and the number of steps can be reduced. As such a material having solubility resistance, for example, tantalum oxide, titanium oxide, and silicon carbide can be suitably used as the surface member 5. In addition, an insulating film such as silicon oxide or silicon nitride can also be suitably used for the surface member 5.

[0034] <Second Embodiment> Next, with reference to Fig. 5, the compliance substrate 50 according to the second embodiment will be described. Fig. 5 is a schematic cross-sectional view of the compliance substrate 50 according to the second embodiment. In the second embodiment, the surface member 5 formed on the surface of the flexible member 6 of the compliance substrate 50 is a laminated member composed of a plurality of materials.

[0035] The surface member 5 according to the second embodiment is a film-like member composed of a first surface layer 52 that contacts the flexible member 6 and a second surface layer 53 that is formed on the first surface layer 52 and contacts the liquid in the liquid flow path 11. The first surface layer 52 is specialized in the function of reducing the deflection of the flexible member 6 due to its internal stress, and is a layer adjacent to the space 7. The second surface layer 53 is specialized in the protective film function, is a layer adjacent to the liquid flow path 11, and contains components different from those of the first surface layer 52. By configuring the surface member 5 in a two-layer structure in this way, it becomes possible to separately control the functions required for the surface member 5 in each layer, and a design that maximizes the effects of the surface member 5 becomes possible. For example, by forming the first surface layer 52 of tantalum oxide and the second surface layer 53 of silicon carbide, the functions of reducing the deflection and the protective film function of the surface member 5 can be maximized. By configuring the surface member 5 with a plurality of layers in this way, the deterioration of the discharge controllability of the substrate 1 for the liquid discharge head can be more effectively suppressed.

[0036] Note that the above configuration is merely an example, and the present invention is not limited to the above configuration. For example, it can be a three-layer configuration provided with an intermediate layer for improving the adhesion between the first surface layer 52 and the second surface layer 53, or a four or more layer configuration.

[0037] <Third Embodiment> Next, referring to FIG. 6, the compliance substrate 50 according to the third embodiment will be described. FIG. 6 is a schematic cross-sectional view of the compliance substrate 50 according to the third embodiment. In the third embodiment, the surface member 5 is a laminated member made of a plurality of materials. Also, in the second embodiment, the thickness of the surface member 5 is uniform throughout, but in the third embodiment, the thickness of the surface member 5 is different between the portion formed on the flexible member 6 side of the compliance substrate 50 and the portion formed on the opposite side. Hereinafter, the portion formed on the flexible member 6 side of the first surface layer 52 is referred to as the upper first surface layer 52a, and the portion formed on the side opposite to the flexible member 6 is referred to as the lower first surface layer 52b. Similarly, the portion formed on the flexible member 6 side of the second surface layer 53 is referred to as the upper second surface layer 53a, and the portion formed on the side opposite to the flexible member 6 is referred to as the lower second surface layer 53b. That is, the upper first surface layer 52a is formed on the flexible member 6, and the lower first surface layer 52b is formed on the base substrate 51. Here, the upper and lower do not represent the posture during the use of the liquid ejection head, but are used for convenience in the up and down directions in FIG. 6.

[0038] When the surface member 5 is formed by selecting a film formation method such as the ALD method that can coat well even inside a three-dimensional structure, the thickness on the flexible member 6 side surface and the other surface of the compliance substrate 50 is about the same as in the second embodiment. However, since the internal stress of the thin film varies depending on the substrate, when the front and back of the substrate are formed of different materials, if the surface member 5 is formed with a uniform thickness throughout, the warping of the entire substrate may change. Therefore, the surface member 5 according to the third embodiment is configured such that the layer thickness is different between the upper first surface layer 52a and the lower first surface layer 52b, and the layer thickness is different between the upper second surface layer 53a and the lower second surface layer 53b. Thus, according to the configuration in which the thickness of the surface member 5 is changed between the flexible member 6 side and the opposite side, the balance of the stress generated on each surface can be controlled. As a result, the warping of the entire compliance substrate 50 can be controlled, and the deterioration of the ejection controllability of the liquid ejection head substrate 1 can be suppressed.

[0039] <Fourth Embodiment> Next, with reference to FIGS. 7(a) and 7(b), the compliance substrate 50 according to the fourth embodiment will be described. FIGS. 7(a) and 7(b) are explanatory views of the compliance substrate 50 according to the fourth embodiment. FIG. 7(a) is a plan view of the compliance substrate 50 according to the fourth embodiment, and is a view of the compliance substrate 50 seen in the stacking direction. Note that the stacking direction is the stacking direction of the liquid ejection head substrate 1 and the compliance substrate 50, and is a direction perpendicular to the adhesion surface 51a of the base substrate 51. FIG. 7(b) is a cross-sectional view taken along line A-A in FIG. 7(a), and shows a schematic cross-sectional view of the compliance substrate 50 according to the fourth embodiment. In the fourth embodiment, the surface member 5 is formed only on a part of the flexible member 6.

[0040] In FIG. 7(a), the outer shape of the space 7 is indicated by a dotted line. In the fourth embodiment, when viewed in the stacking direction, one surface member 5 is formed so as to overlap the space 7 so as to fit inside one space 7. When viewed in the stacking direction, the surface member 5 is formed smaller than the space 7 and is not formed at a position overlapping the adhesion surface 51a of the base substrate 51. That is, in the fourth embodiment, the surface member 5 is formed only at a location adjacent to the space 7 in the stacking direction of the flexible member 6 and where deflection occurs.

[0041] The surface member 5 does not necessarily need to be formed continuously in one piece in the plane direction of the flexible member 6. One advantage when the surface member 5 is patterned in the plane direction and a plurality of them are formed discontinuously is that if film peeling of the surface member 5 occurs at a certain location, it can be limited to local film peeling without causing chain-like peeling of the surrounding film starting from that location. As shown in FIGS. 7(a) and 7(b), by forming the surface member 5 only at a location separating the space 7, which is a deflected portion of the flexible member 6, from the liquid flow path 11, both the effects of correcting deflection and preventing the spread of film peeling can be obtained, and deterioration of the ejection controllability of the liquid ejection head substrate 1 can be suppressed.

[0042] <Fifth Embodiment> Next, with reference to FIGS. 8(a) and 8(b), the compliance substrate 50 according to the fifth embodiment will be described. FIGS. 8(a) and 8(b) are explanatory views of the compliance substrate 50 according to the fifth embodiment. FIG. 8(a) is a plan view of the compliance substrate 50 according to the fifth embodiment, and is a view of the compliance substrate 50 seen in the stacking direction. FIG. 8(b) is a cross-sectional view taken along line B-B of FIG. 8(a), and shows a schematic cross-sectional view of the compliance substrate 50 according to the fifth embodiment. In the fifth embodiment, the surface member 5 is formed only on a part of the flexible member 6.

[0043] In FIG. 8(a), the outer shape of the space 7 is indicated by a dotted line. In the fifth embodiment, when viewed in the stacking direction, the three surface members 5 are formed so as to overlap the space 7 so as to fit inside one space 7. That is, when viewed in the stacking direction, each surface member 5 is formed smaller than the space 7 and is not formed at a position overlapping the adhesive surface 51a of the base substrate 51. Further, the three surface members 5 are arranged side by side in the short direction orthogonal to the longitudinal direction of the space 7 with a space therebetween. That is, also in the fifth embodiment, the surface member 5 is formed only at a location adjacent to the space 7 of the flexible member 6 in the stacking direction and where deflection occurs.

[0044] By adopting a pattern in which the surface member 5 formed only on the deflected portion of the flexible member 6 is further divided in the plane direction as in the configuration of the fifth embodiment, the resistance to film peeling is further improved. Also, in long-term head driving, the effect of suppressing pressure fluctuations can be stably obtained, and the deterioration of the discharge controllability of the substrate 1 for a liquid ejection head can be suppressed in the long term.

[0045] <Sixth Embodiment> Next, with reference to FIGS. 9(a) and 9(b), the compliance substrate 50 according to the sixth embodiment will be described. FIGS. 9(a) and 9(b) are explanatory views of the compliance substrate 50 according to the sixth embodiment. FIG. 9(a) is a plan view of the compliance substrate 50 according to the fifth embodiment, and is a view of the compliance substrate 50 seen in the stacking direction. FIG. 9(b) is a cross-sectional view taken along line C-C of FIG. 9(a), and shows a schematic cross-sectional view of the compliance substrate 50 according to the sixth embodiment. In the sixth embodiment, the surface member 5 is formed only on a part of the flexible member 6.

[0046] In FIG. 9(a), the outer shape of the space 7 is indicated by a dotted line. In the sixth embodiment, when viewed in the stacking direction, the surface member 5 is formed at a position overlapping the adhesion surface 51a of the base substrate 51 and not overlapping the space 7 or the liquid supply port 10. That is, in the sixth embodiment, the surface member 5 is formed only at a portion adhered to the adhesion surface 51a of the flexible member 6 and at a portion where the flexible member 6 does not bend.

[0047] Even if the surface member 5 is not formed at the bent portion of the flexible member 6 in contact with the space 7 as in the configuration of the sixth embodiment and the surface member 5 is formed in other regions, it is possible to indirectly reduce the bending. Such a configuration is preferable because there is no concern that the flexibility is inhibited since the surface member 5 is not directly formed on the active portion that absorbs the pressure fluctuation of the flexible member 6, and there is no concern about performance change due to film peeling. The reason why the bending can be reduced by indirectly forming the surface member 5 is as follows. As described above, the bending is caused in part by the stress resulting from the difference in thermal expansion and contraction between the flexible member 6 and the base substrate 51. Due to the stress, the entire substrate warps, while the flexible member 6 in the portion that is tented (covering) the space 7 has no support from the base of the base substrate 51, so it bends on the spot to relieve the stress. That is, the total stress is distributed between the warp and the bend of the substrate, and if the warp of the substrate can be reduced, the bend can be reduced as a result. Therefore, by forming the surface member 5 in a region other than the bent portion to reduce the warp of the substrate, it is possible to indirectly reduce the bend of the flexible member 6. The flexible member 6 relieves the stress by bending on the spot because there is no support from the base of the base substrate 51. That is, the total stress is distributed between the warp and the bend of the substrate, and if the warp of the substrate can be reduced, the bend can be reduced as a result. Therefore, by forming the surface member 5 in a region other than the bent portion to reduce the warp of the substrate, it is possible to indirectly reduce the bend of the flexible member 6.

[0048] <Seventh Embodiment> Next, with reference to FIGS. 10(a) to 10(f), the compliance substrate 50 according to the seventh embodiment will be described. FIGS. 10(a) to 10(f) are explanatory views of a manufacturing method of the compliance substrate 50 according to the seventh embodiment. In the seventh embodiment, the surface member 5 is formed on the surface on the space 7 side on the flexible member 6.

[0049] FIG. 10(a) shows a base substrate 51 provided with an air communication port 12 connected to the space 7. The air communication port 12 penetrates from the space 7 to the surface on the side opposite to the adhesive surface 51a to which the flexible member 6 of the base substrate 51 is adhered. By providing the air communication port 12, the internal pressure of the space 7 is released to the atmosphere. Therefore, the air communication port 12 is arranged for the purpose of eliminating the pressure difference inside and outside the space 7 at the manufacturing stage to improve productivity, improving the mobility of the flexible member 6, and the like.

[0050] As shown in FIGS. 10(b) to 10(d), after joining the flexible member 6 to the base substrate 51 via the adhesive 61, the flexible member 6 is communicated with the liquid supply port 10 by dry etching or the like. FIG. 10(b) shows a state where the adhesive 61 is applied on the base substrate 51. FIG. 10(c) shows a state where the flexible member 6 is fixed on the base substrate 51. FIG. 10(d) shows a state where an opening 6c is formed in the flexible member 6. The manufacturing processes shown in these figures are the same processes as FIGS. 4(a) to 4(d) according to the first embodiment.

[0051] FIG. 10(e) shows a state in which the surface member 5 is formed on the surface of the flexible member 6. The surface member 5 can be formed by depositing it on the base substrate 51 using a vapor deposition method such as a vapor deposition method, a sputtering method, or a CVD method. At this time, the surface member 5 is also deposited on the surface of the flexible member 6 on the space 7 side through the air communication port 12. Preferably, a deposition method excellent in film formation on a three-dimensional surface such as an ALD method or a Molecular Layer Deposition (MLD) method can be used. According to such a deposition method, the surface member 5 can be uniformly deposited regardless of the opening size of the air communication port 12.

[0052] As shown in FIG. 10(e), depending on the deposition method, the surface member 5 may be deposited on both sides of the flexible member 6. In the seventh embodiment, the surface member 5 formed on the surface on the side opposite to the space 7 side and on the side of the liquid flow path 11 is removed in a later process. However, in the application of the present invention, the surface member 5 formed on the surface on the space 7 side does not necessarily have to be removed. The surface member 5 deposited on the surface on the side opposite to the space 7 may be left deposited without being removed, or a part may be left in the film thickness direction (lamination direction) or the plane direction without being completely removed, and it can be used as an adjustment allowance for controlling the amount of deflection.

[0053] By going through the above-described steps, a compliance substrate 50 in which the surface member 5 is disposed on the surface of the flexible member 6 on the space 7 side and the deflection is suppressed can be obtained. In the seventh embodiment, the arrangement relationship between the surface member 5 and the flexible member 6 is reversed as compared with the first embodiment shown in FIGS. 4(a) to (e). Therefore, in order to reduce the deflection of the flexible member 6 generated during manufacturing, it is also necessary to reverse the magnitude relationship between the thermal expansion coefficients of the surface member 5 and the flexible member 6. That is, a material is selected so that the thermal expansion coefficient of the surface member 5 is larger than that of the flexible member 6. For example, for the flexible member 6, about 10 ppm or less When using the low thermal expansion organic resin film, as the surface member 5, for example, by using a metal thin film having a thermal expansion coefficient of about several tens of ppm or a polymer thin film of about several hundreds of ppm, the deflection of the flexible member 6 can be suppressed.

[0054] <Eighth Embodiment> Next, with reference to FIGS. 15(a) to (e), the substrate 1 for a liquid ejection head according to the eighth embodiment will be described. FIGS. 15(a) to (e) are explanatory views of the manufacturing method of the substrate 1 for a liquid ejection head according to the eighth embodiment. In the eighth embodiment, the surface member 5 is continuously formed on the surface of the flexible member 6 and the surface of the substrate 1 for a liquid ejection head. The materials applicable to the surface member 5 and the preferable thickness are the same as those described in the section of the first embodiment.

[0055] FIGS. 15(a) to (e) show the manufacturing method of the substrate 1 for a liquid ejection head according to the eighth embodiment. FIG. 15(a) is in the same form as the compliance substrate 50 described in the section of the first embodiment. FIG. 15(b) shows a state where the flow path substrate 40 is formed on the compliance substrate 50. FIG. 15(c) shows a state where the pressure generation substrate 30 is further formed. FIG. 15(d) shows a state where the nozzle substrate 20 is further formed.

[0056] The flow path substrate 40, the pressure generation substrate 30, and the nozzle substrate 20 are laminated in this order by bonding. The bonding can be performed regardless of the form of the substrate, such as in wafer form or chip form, and the method of directly bonding the substrate surfaces to each other or the bonding via an adhesive layer such as a metal film, an organic resin, or an inorganic film can be used. FIG. 15(e) shows a state where the surface member 5 is formed on the surfaces of the substrate 1 for a liquid ejection head and the flexible member 6. By forming the surface member 5 after bonding the compliance substrate 50, the flow path substrate 40, the pressure generation substrate 30, and the nozzle substrate 20, the surface member 5 is continuously formed on the surfaces of the flexible member 6 and the substrate 1 for a liquid ejection head.

[0057] By adopting such a manufacturing method, the surface member 5 can continuously cover the entire surface of the flexible member 6, including the nozzles 2, pressure chambers 3, and liquid flow paths (individual supply ports 8 and common flow paths 9) that constitute the liquid ejection head substrate 1, that is, the liquid path including the liquid flow paths (individual supply ports 8 and common flow paths 9), pressure chambers 3, and nozzles 2, all at once. As a result, all the portions in contact with the liquid, including the bonding interfaces between the substrates and the adhesive layers, can be covered with the surface member 5, and the protectiveness against the liquid can be improved. By forming the surface member 5 over the entire liquid ejection head substrate 1 in this way, it is possible to reduce the deflection of the flexible member 6 and protect the liquid ejection head substrate 1 from the liquid at the same time, and the manufacturing cost can be reduced. The film formation method of the surface member 5 in this case is not limited, but in the liquid ejection head substrate 1 in which the liquid flow paths, nozzles, pressure chambers, etc. are complexly arranged, for example, a method excellent in conformal film formation inside a three-dimensional structure such as the ALD method can be preferably used.

[0058] <Embodiment 9> Embodiment 9 will be described with reference to FIG. 16. FIG. 16 is a schematic cross-sectional view of a liquid ejection head substrate according to Embodiment 9. In Embodiment 9, the base substrate 51 of the compliance substrate 50 is provided on the nozzle substrate 20 side with respect to the pressure generation substrate 30. That is, the liquid ejection head substrate 1 according to Embodiment 9 has the nozzle substrate 20, the compliance substrate 50, the pressure generation substrate 30, and the flow path substrate 40 in this order. The materials applicable to the surface member 5 and the preferred thickness are the same as those described in the section of Embodiment 1.

[0059] In this embodiment, as an example, the flow path substrate 40 and the pressure generation substrate 30 are formed of a silicon substrate, and the base substrate 51 is formed of stainless steel (SUS). The present invention can be preferably used even for a liquid ejection head using a liquid ejection head substrate having a laminated structure as shown in FIG. 16.

[0060] Next, regarding some of the above-described embodiments, the configuration of the actually manufactured substrate 1 for a liquid ejection head and the ejection evaluation using the substrate 1 for a liquid ejection head will be described.

[0061] <Example 1> Example 1 will be described with reference to FIGS. 11 and 12. FIG. 11 is a schematic cross-sectional view of the substrate 1 for a liquid ejection head according to Example 1. In Example 1, as in the first embodiment, the surface member 5 is provided on the entire surface of the flexible member 6 on the liquid flow path 11 side. FIG. 12 is a schematic cross-sectional view of the substrate 1 for a liquid ejection head according to the comparative example. In the comparative example, the surface member 5 is not provided. The substrate 1 for a liquid ejection head according to Example 1 is configured by arranging a compliance substrate 50, a flow path substrate 40, a pressure generation substrate 30, and a nozzle substrate 20 in this order.

[0062] In Example 1, a silicon substrate was used for the base substrate 51 of the compliance substrate 50, a polyimide film was used as the flexible member 6, and a titanium oxide thin film was used for the surface member 5. In Example 1, the thermal expansion coefficient of the base substrate 51, which is a silicon substrate, is less than approximately 5 ppm / K, and the thermal expansion coefficient of the flexible member 6, which is a polyimide film, is approximately 10 to 50 ppm / K. Further, the thermal expansion coefficient of the surface member 5, which is a titanium oxide thin film, is approximately 10 ppm / K.

[0063] In manufacturing the substrate 1 for a liquid ejection head according to Example 1, first, a resist pattern was drawn on the silicon substrate by photolithography, and then dry etching was performed to form the space 7 and the liquid supply port 10, thereby manufacturing the base substrate 51. Next, an adhesive mainly composed of an organic resin was applied to the adhesion surface 51a on which the space 7 of the base substrate 51 was formed, and a polyimide film with a thickness of 3 μm was attached to the adhesion surface 51a. Next, a heat treatment at 200°C was performed to cure the adhesive and fix the polyimide film to the base substrate 51. After fixing, the polyimide film was bent about 2 μm toward the space 7 side.

[0064] After a polyimide film, which is a flexible member 6, is attached to the base substrate 51, in order to remove the polyimide film in the portion corresponding to the liquid supply port 10, pattern formation using photoresist and etching were performed to penetrate the liquid supply port 10. Next, a titanium oxide thin film was formed to a thickness of 100 nm by ALD as the surface member 5, and the compliance substrate 50 was produced. In this state, the deflection of the polyimide film toward the space 7 was about 0.3 μm, which was reduced compared to the 2-μm deflection after fixation. The compliance substrate 50 produced in this way was joined to the nozzle substrate 20, pressure generation substrate 30, and flow path substrate 40 prepared separately to produce the liquid discharge head substrate 1.

[0065] The manufacturing method of the liquid discharge head substrate 1 according to the comparative example is the same as that of Example 1 except that the surface member 5 is not formed. Therefore, as shown in FIG. 12, in the liquid discharge head substrate 1 according to the comparative example, the surface member 5 is not formed on the surface of the flexible member 6 or the base substrate 51. And the amount of deflection of the flexible member 6 toward the space 7 in the state where the pressure generation means 4 in the comparative example is not generating pressure is larger than that of the liquid discharge head substrate 1 according to Example 1.

[0066] Using the liquid discharge head substrate 1 of Example 1 produced as described above and the liquid discharge head substrate 1 of the comparative example, discharge evaluation was performed. In the discharge evaluation, liquid was discharged using each liquid discharge head substrate 1, and its behavior was observed. In the liquid discharge head substrate 1 according to the comparative example, changes in the flying speed and volume of the liquid considered to be crosstalk occurred between the nozzles 2 adjacent to each other. On the other hand, in the liquid discharge head substrate 1 according to Example 1, crosstalk did not occur under the same driving conditions, and an improvement in the effect of suppressing pressure fluctuations by the flexible member 6 was observed.

[0067] <Example 2> Example 2 will be described with reference to FIG. 13. FIG. 13 is a schematic cross-sectional view of the substrate 1 for a liquid ejection head according to Example 2. In Example 2, as in the fifth embodiment, the surface member 5 is provided only on a part of the surface of the flexible member 6 on the liquid flow path 11 side. And a plurality of surface members 5 are provided adjacent to each other at intervals in a direction parallel to the bonding surface 51a (see FIG. 10(a)) of the base substrate 51.

[0068] In manufacturing the substrate 1 for a liquid ejection head according to Example 2, first, a compliance substrate 50 is manufactured in the same manner as in Example 1. Next, a dry film resist is attached to the surface on the polyimide film side, a resist pattern is drawn by photolithography, and then wet etching is performed to pattern the titanium oxide thin film. The pattern is in a strip shape, and a titanium oxide thin film is formed in the region of the polyimide film at a position overlapping with the space 7 when the compliance substrate 50 is viewed in plan. Through these steps, the titanium oxide thin film is formed so that a plurality of surface members 5 are arranged at intervals in a direction parallel to the bonding surface 51a of the base substrate 51. The deflection of the polyimide film toward the space 7 in this state was about 0.5 μm, which was reduced compared to the deflection of 2 μm after fixing.

[0069] Using the substrate 1 for a liquid ejection head of Example 2 manufactured as described above, ejection evaluation was performed in the same manner as in Example 1. Also in the substrate 1 for a liquid ejection head of Example 2, crosstalk did not occur as in Example 1, and the effect of suppressing pressure fluctuations was improved. Further, even in long-term continuous ejection, the ejection variation between nozzles was small, and the effect of suppressing the film peeling of the titanium oxide thin film which is the surface member 5 was obtained.

[0070] <Example 3> Example 3 will be described with reference to FIG. 14. FIG. 14 is a schematic cross-sectional view of the substrate 1 for a liquid ejection head according to Example 3. In Example 3, as in the seventh embodiment, the surface member 5 is provided on the surface of the flexible member 6 on the space 7 side.

[0071] In Example 3, a silicon substrate was used for the base substrate 51 of the compliance substrate 50, a polyimide film was used as the flexible member 6, and a polyurethane resin was used for the surface member 5. In Example 3, the coefficient of thermal expansion of the base substrate 51, which is a silicon substrate, is less than approximately 5 ppm / K, and the coefficient of thermal expansion of the flexible member 6, which is a polyimide film, is approximately 10 to 50 ppm / K. Also, the coefficient of thermal expansion of the surface member 5, which is a titanium oxide thin film, is approximately 100 to 200 ppm / K.

[0072] In fabricating the substrate 1 for a liquid ejection head according to Example 3, first, a resist pattern was drawn on the silicon substrate by photolithography, and then dry etching was performed to form the space 7, the liquid supply port 10, and the air communication port 12, thereby fabricating the base substrate 51. Next, an adhesive mainly composed of an organic resin was applied to the adhesion surface 51a where the space 7 of the base substrate 51 was formed, and a polyimide film with a thickness of 3 μm was attached to the adhesion surface 51a. Next, a heat treatment at 200 °C was performed to cure the adhesive and fix the polyimide film to the base substrate 51. After fixation, the polyimide film was bent about 1 μm toward the space 7 side.

[0073] After the polyimide film, which is the flexible member 6, was attached to the base substrate 51, in order to remove the polyimide film in the portion corresponding to the liquid supply port 10, pattern formation by photoresist and etching were performed to penetrate the liquid supply port 10. Next, as the surface member 5, a polyurethane resin was deposited by vapor deposition polymerization on the surface on the space 7 side of the polyimide film from the air communication port 12 side to form a film with a thickness of 1 μm, thereby fabricating the compliance substrate 50. In this state, the bending of the polyimide film toward the space 7 side was about 0.2 μm, which was reduced compared to the bending of 1 μm after fixation.

[0074] Using the substrate 1 for a liquid ejection head of Example 3 fabricated as described above, ejection evaluation was performed in the same manner as in Example 1. Also in the substrate 1 for a liquid ejection head of Example 3, crosstalk did not occur as in Example 1, and the effect of suppressing pressure fluctuations was improved.

[0075] <Example 4> Embodiment 4 will be described with reference to FIG. 17. FIG. 17 is a schematic cross-sectional view of the substrate 1 for a liquid ejection head according to Embodiment 4. In Embodiment 4, similar to the eighth embodiment, the surface member 5 is formed so as to continuously cover the surface of the flexible member 6, the surface of the substrate 1 for a liquid ejection head, and the inner wall surface of the flow path.

[0076] In Embodiment 4, a space 7 is formed on the surface side of the substrate 1 for a liquid ejection head where the nozzles 2 are formed, and the positional relationship with the flexible member 6 in the cross-sectional direction of the substrate 1 for a liquid ejection head is different from that in Embodiments 1 to 3. Further, the substrate 1 for a liquid ejection head according to Embodiment 4 is configured by arranging a nozzle substrate 20, a compliance substrate 50, a pressure generation substrate 30, and a flow path substrate 40 in this order.

[0077] In manufacturing the substrate 1 for a liquid ejection head according to Embodiment 4, first, a base substrate 51 was manufactured in the same manner as in Embodiment 1, and after attaching a flexible member 6 such as a polyimide film, it was patterned. Thereby, the compliance substrate 50 before forming the surface member 5 was manufactured. Next, by sequentially bonding the separately prepared pressure generation substrate 30, flow path substrate 40, and nozzle substrate 20, the substrate 1 for a liquid ejection head before forming the surface member 5 was formed. Finally, by forming the surface member 5, the substrate 1 for a liquid ejection head having the schematic cross-sectional view shown in FIG. 17 was manufactured.

[0078] Using the substrate 1 for a liquid ejection head of Embodiment 4 manufactured as described above, ejection evaluation was performed in the same manner as in Embodiment 1. Also in the substrate 1 for a liquid ejection head of Embodiment 4, crosstalk did not occur in the same manner as in Embodiment 1, and the effect of suppressing pressure fluctuations was improved. Further, when the substrate 1 for a liquid ejection head was immersed in a liquid and a heat cycle test (0.15 MPa, 120 °C, 30 cycles) was performed under pressure, no peeling of the substrate or significant dissolution inside the flow path was confirmed, and it was found that the protective effect of the surface member 5 continuously covering the substrate 1 for a liquid ejection head was high.

[0079] In addition, each of the above-described embodiments was configured on the premise that the flexible member 6 bends toward the space 7 side. However, the present invention is also applicable to a configuration in which the flexible member 6 bends toward the liquid flow path 11 side. For example, when an inorganic film or a metal film having a smaller coefficient of thermal expansion than the organic resin is used for the flexible member 6 and a substrate having a large coefficient of thermal expansion of an amorphous material such as an organic resin substrate or a glass substrate is used for the base substrate 51, the coefficient of thermal expansion of the flexible member 6 can be smaller than that of the base substrate 51. When the coefficient of thermal expansion of the flexible member 6 is smaller than that of the base substrate 51, the flexible member 6 may bend toward the liquid flow path 11 side after the heat treatment of the adhesive 61. In such a case, by providing the surface member 5 having a larger coefficient of thermal expansion than the flexible member 6 on the surface of the flexible member 6 on the liquid flow path 11 side, or by providing the surface member 5 having a smaller coefficient of thermal expansion than the flexible member 6 on the surface of the flexible member 6 on the space 7 side, the bending of the flexible member 6 can be reduced.

[0080] In addition, the configurations of the above-described embodiments can be combined as appropriate. For example, a plurality of surface members 5 may be arranged and formed over the entire surface of the flexible member 6 on the liquid flow path 11 side as in the first embodiment, or as in the fourth or fifth embodiment. Further, for example, the surface member 5 composed of a plurality of layers as in the second or third embodiment may be formed on the surface of the flexible member 6 on the space 7 side as in the seventh embodiment.

[0081] The disclosure of the present embodiment includes the following configurations and methods. (Configuration 1) A liquid discharge head for discharging a liquid, a nozzle from which the liquid is discharged, and pressure generating means for generating pressure for discharging the liquid from the nozzle, a pressure chamber formed inside the pressure generating means, a liquid flow path communicating with the nozzle, a space formed adjacent to the liquid flow path and separated from the liquid flow path, a base body constituting a wall portion forming the liquid flow path and a wall portion forming the space, A resin flexible member that is fixed to the substrate, separates the liquid flow path from the space, and bends in response to pressure fluctuations generated in the pressure chamber. Comprising A liquid ejection head, characterized in that an inorganic film is provided on the surface of the flexible member. (Configuration 2) The liquid ejection head according to Configuration 1, wherein the inorganic film is configured to reduce the deflection of the flexible member in a state where the pressure generating means is not generating pressure. (Configuration 3) The liquid ejection head according to Configuration 1 or 2, wherein the inorganic film is formed on the surface of the flexible member facing the liquid flow path side. (Configuration 4) The thermal expansion coefficient of the flexible member is larger than that of the substrate, The liquid ejection head according to Configuration 3, wherein the thermal expansion coefficient of the inorganic film is smaller than that of the flexible member. (Configuration 5) The liquid ejection head according to Configuration 1 or 2, wherein the inorganic film is formed on the surface of the flexible member facing the space side. (Configuration 6) The thermal expansion coefficient of the flexible member is smaller than that of the substrate, The liquid ejection head according to Configuration 5, wherein the thermal expansion coefficient of the inorganic film is larger than that of the flexible member. (Configuration 7) The liquid ejection head according to any one of Configurations 1 to 6, wherein the thickness of the inorganic film is thinner than the thickness of the flexible member. (Configuration 8) The liquid ejection head according to any one of Configurations 1 to 7, wherein the flexible member is provided at a position that overlaps the space and does not overlap the fixing surface when viewed in a direction perpendicular to the fixing surface of the substrate for fixing the flexible member. (Configuration 9) The liquid ejection head according to Configuration 8, wherein a plurality of the flexible members are arranged adjacent to each other at intervals in a direction parallel to the fixing surface. (Configuration 10) The flexible member is provided at a position that overlaps with the fixing surface and does not overlap with the space when viewed in a direction perpendicular to the fixing surface of the base body to which the flexible member is fixed, according to any one of Configurations 1 to 9 of the liquid ejection head. (Configuration 11) The inorganic film contains at least one of titanium oxide, tantalum oxide, and silicon carbide, according to any one of Configurations 1 to 10 of the liquid ejection head. (Configuration 12) The inorganic film has a first surface layer adjacent to the space and a second surface layer that contains a component different from that of the first surface layer and is adjacent to the liquid flow path, according to any one of Configurations 1 to 11 of the liquid ejection head. (Configuration 13) The first surface layer contains tantalum oxide, and the second surface layer contains silicon carbide, according to the liquid ejection head of Configuration 12. (Configuration 14) The inorganic film is also provided on the surface of the base body opposite to the fixing surface for fixing the flexible member, according to any one of Configurations 1 to 13 of the liquid ejection head. (Configuration 15) The thickness of the portion of the inorganic film provided on the surface of the flexible member is different from the thickness of the portion on the surface of the base body opposite to the fixing surface, according to the liquid ejection head of Configuration 14. (Configuration 16) The base body is formed of a silicon substrate, according to any one of Configurations 1 to 15 of the liquid ejection head. (Configuration 17) The nozzle substrate including the nozzle, the pressure chamber substrate including the pressure chamber, and the flow path substrate including the liquid flow path communicating with the pressure chamber are provided in this order, and the inorganic film is provided so as to continuously cover the liquid path including the liquid flow path, the pressure chamber, and the nozzle, according to any one of Configurations 1 to 16 of the liquid ejection head. (Method 1) A nozzle from which a liquid is discharged, pressure generating means for generating a pressure for discharging the liquid from the nozzle, a pressure chamber formed inside the pressure generating means, a liquid flow path communicating with the nozzle, a space formed adjacent to the liquid flow path and separated from the liquid flow path, a base body constituting a wall portion forming the liquid flow path and a wall portion forming the space, a resin-made flexible member fixed to the base body, separating the liquid flow path and the space, and flexing in response to pressure fluctuations generated in the pressure chamber, and an inorganic film provided on the surface of the flexible member. A method for manufacturing a liquid discharge head, comprising: a step of applying an adhesive to the surface of the base body; a step of attaching the flexible member to the surface of the base body to which the adhesive has been applied; a step of heat-treating the adhesive to cure it; a step of forming the inorganic film on the surface of the flexible member; A method for manufacturing a liquid discharge head, including the above steps. (Method 2) The manufacturing method of the liquid discharge head according to Method 1, wherein the inorganic film is formed so as to cover the exposed surfaces of the base body and the flexible member. (Method 3) The thermal expansion coefficient of the flexible member is larger than that of the base body, and the thermal expansion coefficient of the inorganic film is smaller than that of the flexible member. The manufacturing method of the liquid discharge head according to Method 1 or 2, wherein the inorganic film is formed on the surface opposite to the fixed surface of the flexible member fixed to the base body. (Method 4) The thermal expansion coefficient of the flexible member is larger than that of the base body, and the thermal expansion coefficient of the inorganic film is larger than that of the flexible member. The inorganic film is formed on the fixed surface of the flexible member fixed to the base body and on the surface opposite to the fixed surface. The manufacturing method of the liquid discharge head according to Method 1 or 2, including a step of removing the inorganic film formed on the fixed surface. (Method 5) In the step of forming the inorganic film on the surface of the flexible member, the inorganic film is simultaneously formed on at least one surface of the nozzle, the liquid flow path, the pressure chamber, and the pressure generating means. A method for manufacturing a liquid ejection head according to any one of Methods 1 to 4.

Explanation of Signs

[0082] 1... Substrate for liquid ejection head, 2... Nozzle, 3... Pressure chamber, 4... Pressure generating means, 5... Surface member (inorganic film), 6... Flexible member, 7... Space, 11... Liquid flow path

Claims

1. A liquid ejection head that ejects liquid, A nozzle for discharging liquid; a pressure generating means for generating a pressure for discharging liquid from the nozzle; a pressure chamber formed therein with the pressure generating means; A liquid flow path communicating with the nozzle; a space formed adjacent to the liquid flow path and separated from the liquid flow path; a base body constituting a wall portion that forms the liquid flow path and a wall portion that forms the space; a flexible member made of resin, the flexible member being fixed to the base, separating the liquid flow path from the space, and bending in response to pressure fluctuations occurring in the pressure chamber; Equipped with The liquid ejection head according to claim 1, wherein an inorganic film is provided on a surface of the flexible member.

2. 2. The liquid ejection head according to claim 1, wherein the inorganic film is configured to reduce bending of the flexible member when the pressure generating means is not generating pressure.

3. The liquid ejection head according to claim 1 , wherein the inorganic film is formed on a surface of the flexible member facing the liquid flow path.

4. The thermal expansion coefficient of the flexible member is greater than the thermal expansion coefficient of the base body; The liquid ejection head according to claim 3 , wherein the thermal expansion coefficient of the inorganic film is smaller than the thermal expansion coefficient of the flexible member.

5. The liquid ejection head according to claim 1 , wherein the inorganic film is formed on a surface of the flexible member facing the space.

6. The thermal expansion coefficient of the flexible member is smaller than the thermal expansion coefficient of the base body, The liquid ejection head according to claim 5 , wherein the thermal expansion coefficient of the inorganic film is greater than the thermal expansion coefficient of the flexible member.

7. The liquid ejection head according to claim 1 , wherein the inorganic film has a thickness smaller than a thickness of the flexible member.

8. The liquid ejection head according to claim 1 , wherein the flexible member is provided at a position that overlaps with the space and does not overlap with the fixing surface when viewed in a direction perpendicular to a fixing surface of the base that fixes the flexible member.

9. The liquid ejection head according to claim 8 , wherein the flexible members are arranged adjacent to each other at intervals in a direction parallel to the fixing surface.

10. The liquid ejection head according to claim 1 , wherein the flexible member is provided at a position that overlaps with the fixing surface but does not overlap with the space when viewed in a direction perpendicular to a fixing surface of the base to which the flexible member is fixed.

11. The liquid ejection head according to claim 1 , wherein the inorganic film contains at least one of titanium oxide, tantalum oxide, and silicon carbide.

12. The inorganic film includes a first surface layer adjacent to the space and a component different from that of the first surface layer.

2. The liquid ejection head according to claim 1, further comprising a second surface layer adjacent to the liquid flow path.

13. the first surface layer comprises tantalum oxide; The liquid ejection head according to claim 12 , wherein the second surface layer comprises silicon carbide.

14. 2. The liquid ejection head according to claim 1, wherein the inorganic film is also provided on a surface of the base opposite to a fixing surface for fixing the flexible member.

15. The liquid ejection head according to claim 14 , wherein a thickness of the inorganic film at a portion provided on the surface of the flexible member is different from a thickness of a portion of the inorganic film on a surface opposite to the fixing surface.

16. The liquid ejection head according to claim 1 , wherein the base body is formed of a silicon substrate.

17. 2. The liquid ejection head according to claim 1, comprising, in that order, a nozzle substrate having the nozzles, a pressure chamber substrate having the pressure chambers, and a flow path substrate having the liquid flow paths communicating with the pressure chambers, and the inorganic film is provided so as to continuously cover a liquid path including the liquid flow paths, the pressure chambers, and the nozzles.

18. a liquid ejection head including a nozzle for ejecting liquid, a pressure generating means for generating a pressure for ejecting liquid from the nozzle, a pressure chamber in which the pressure generating means is formed, a liquid flow path communicating with the nozzle, a space formed adjacent to the liquid flow path and separated from the liquid flow path, a base constituting a wall portion forming the liquid flow path and a wall portion forming the space, a flexible member made of resin that is fixed to the base, separates the liquid flow path from the space, and bends in response to pressure fluctuations generated in the pressure chamber, and an inorganic film provided on a surface of the flexible member, applying an adhesive to a surface of the substrate; attaching the flexible member to the surface of the base on which the adhesive has been applied; A step of curing the adhesive by heat treatment; forming the inorganic film on a surface of the flexible member; A method for manufacturing a liquid ejection head, comprising:

19. The method for manufacturing a liquid ejection head according to claim 18 , wherein the inorganic film is formed so as to cover the exposed surfaces of the base body and the flexible member.

20. the thermal expansion coefficient of the flexible member is greater than the thermal expansion coefficient of the base body, and the thermal expansion coefficient of the inorganic film is smaller than the thermal expansion coefficient of the flexible member; The method for manufacturing a liquid ejection head according to claim 18 , wherein the inorganic film is formed on a surface of the flexible member opposite to a fixed surface that is fixed to the base body.

21. the thermal expansion coefficient of the flexible member is greater than that of the base body, and the thermal expansion coefficient of the inorganic film is greater than that of the flexible member; the inorganic film is formed on a fixed surface of the flexible member that is fixed to the base body and on a surface opposite to the fixed surface, The method for manufacturing a liquid ejection head according to claim 18 , further comprising the step of removing the inorganic film formed on the fixed surface.

22. 20. The method for manufacturing a liquid ejection head according to claim 18, wherein in the step of forming the inorganic film on the surface of the flexible member, the inorganic film is also formed on a surface of at least one of the nozzle, the liquid flow path, the pressure chamber, and the pressure generating means at the same time.

Images