Liquid discharge head and manufacturing method of liquid discharge head

Abstract

To provide a liquid discharge head that facilitates insulation protection of electrode wiring and a manufacturing method of the liquid discharge head.SOLUTION: A liquid discharge head includes a substrate, an actuator, a cover member, an insulation material, and an insulation film. The substrate has an electrode on a surface. The actuator is provided on the surface of the substrate and has a plurality of pressure chambers communicating with a nozzle for discharging liquid. The cover member is joined to a side surface section of the actuator and has a throttle opening having larger fluid resistance than that in the pressure chamber at a position facing the plurality of pressure chambers. The insulation material is filled in a gap formed between the surface of the substrate and the cover member. The insulation film covers the electrode on the substrate.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] FIELD Embodiments of the present invention relate to a liquid ejection head and a method for manufacturing a liquid ejection head. [Background technology]

[0002] High productivity is required for liquid ejection heads such as inkjet heads, making higher speeds and droplet volumes essential. For example, shear-mode shared-wall inkjet heads use shear modes that allow for large displacement. The high rigidity and high power of the pressure chambers formed by the piezoelectric element make them suitable for ejecting high-viscosity inks and large droplets. However, because the same drive column is shared by two pressure chambers, they are based on a so-called three-cycle drive, which limits the simultaneous drive capacity to one-third. To achieve higher speeds, independent drive heads have been developed, in which dummy pressure chambers are used on both sides of the drive pressure chamber and each pressure chamber is driven by two independent drive columns. For example, multiple grooves are formed in the piezoelectric element, and the entrances and exits of every other groove are blocked with photosensitive resin. The blocked grooves serve as air chambers (dummy chambers), while the grooves with open entrances and exits that connect to the common chamber serve as pressure chambers.

[0003] In an inkjet head, after an ink droplet is ejected, ink is replenished from the common liquid chamber, but this overshoot at the nozzle causes a meniscus to bulge. The smaller the fluid resistance between the common liquid chamber and the nozzle, the greater the overshoot. Unless this overshoot subsides, the same ejection quality cannot be achieved. To increase speed, it is also important to quickly resolve the meniscus bulge. Furthermore, the larger the ink droplet, the more pronounced the meniscus bulge. To address this issue, increasing the fluid resistance at the pressure chamber inlet is effective. One effective way to increase fluid resistance is to reduce the cross-section of the pressure chamber (in the direction in which the ink is replenished). However, in a shear-mode, shared-wall inkjet head, forming a photosensitive resin resistor at the pressure chamber inlet / outlet makes it difficult to ensure accurate throttling. Alternatively, a ceramic plate-shaped cover member can be bonded and processed to the pressure chamber inlet / outlet.

[0004] When a cover member is bonded, a gap may form between the cover member and the substrate. In this case, when an insulating film made of adhesive is sprayed onto the electrode-forming surface of the substrate by a spray or the like, the cover member acts as a canopy, making it difficult to insulate and protect the electrode wiring directly below the cover member. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-189031 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the present invention is to provide a liquid ejection head that facilitates insulation protection of electrode wiring, and a method for manufacturing the liquid ejection head. [Means for solving the problem]

[0007] A liquid ejection head according to one embodiment includes a substrate, an actuator, a cover member, an insulating material, and an insulating film. The substrate has electrodes on its surface. The actuator is provided on the surface of the substrate and has a plurality of pressure chambers that communicate with nozzles that eject liquid. The cover member is bonded to a side portion of the actuator and has aperture openings facing the plurality of pressure chambers that have a higher fluid resistance than the interior of the pressure chambers. The insulating material fills a gap formed between the surface of the substrate and the cover member. The insulating film covers the electrodes on the substrate. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing an inkjet head according to an embodiment. [Figure 2] FIG. 2 is a plan view showing the configuration of an inkjet head according to the embodiment. [Figure 3]FIG. 2 is a plan view showing a configuration of a part of the actuator base of the inkjet head. [Figure 4] FIG. 2 is a bottom view showing the configuration of the actuator base of the inkjet head. [Figure 5] FIG. 2 is a cross-sectional view showing a configuration of a part of the inkjet head. [Figure 6] FIG. 2 is a perspective view showing the configuration of an actuator base of the inkjet head. [Figure 7] FIG. 2 is a cross-sectional view showing the configuration of an actuator base of the inkjet head. [Figure 8] 3A to 3C are explanatory diagrams showing a method of manufacturing the inkjet head. [Figure 9] FIG. 2 is an explanatory diagram showing the configuration of an actuator base of the inkjet head. [Figure 10] FIG. 10 is an explanatory diagram of an inkjet head according to Test Example 1 and Test Example 2. [Figure 11] 10 is a graph showing the ejection speed of the inkjet head according to Test Example 1. [Figure 12] 10 is a graph showing the ejection speed of an inkjet head according to Test Example 2. [Figure 13] 10 is a graph showing meniscus recovery characteristics of inkjet heads according to Test Examples 1 and 2. [Figure 14] FIG. 1 is a schematic diagram showing an inkjet printer according to an embodiment. [Figure 15] FIG. 10 is a cross-sectional view showing the configuration of an actuator base of an inkjet head according to a second embodiment. [Figure 16] FIG. 2 is an explanatory diagram showing the configuration of a substrate and an actuator of the inkjet head. DETAILED DESCRIPTION OF THE INVENTION

[0009] The structure of an inkjet head 10, which is a liquid ejection head according to the first embodiment, will be described below with reference to FIGS. 1 to 6. FIG. 1 is a perspective view of an inkjet head according to the first embodiment. FIG. 2 shows a head unit 130 including a pair of inkjet heads 10. FIG. 3 is a plan view showing the structure of a substrate 21 and an actuator 22, and FIG. 4 is a bottom view of an actuator base 11. FIG. 5 is a cross-sectional view showing the structure of a portion of an inkjet head. FIGS. 6 and 7 are a perspective view and a cross-sectional view showing the structure of an actuator base. In FIG. 6, the pattern wiring 211 is omitted. FIG. 8 is an explanatory diagram of a manufacturing process for an inkjet head. FIG. 9 is an explanatory diagram showing the structure of the actuator base 11, and is a cross-sectional photograph showing the state before the insulating film 212 is formed.

[0010] In the drawing, X, Y, and Z respectively represent a first direction, a second direction, and a third direction that are perpendicular to one another. In this embodiment, the directions are described based on the orientation of the inkjet head 10, where the row direction of the nozzles 28 and the pressure chambers 31 is the X axis, the extension direction of the pressure chambers 31 is the Y axis, and the ejection direction of the liquid is the Z axis, but the present invention is not limited to this.

[0011] As shown in Figures 1 to 7, the inkjet head 10 is a so-called side-shooter, share-mode, share-wall inkjet head. For example, as shown in Figure 2, two inkjet heads 10, each with a pair of actuators, may be combined to form a four-row integrated head unit. The inkjet head 10 is a device for ejecting ink and is mounted inside an inkjet printer, for example. Figure 1 and other figures show only one head body of the inkjet head 10. For example, the inkjet head 10 is an independently driven inkjet head in which pressure chambers 31 and dummy chambers 32 are alternately arranged. The dummy chambers 32 are air chambers to which ink is not supplied and do not have nozzles 28.

[0012] The inkjet head 10 includes an actuator base 11, a nozzle plate 12, and a frame 13. The actuator base 11 is an example of a substrate. An ink chamber 27 is formed inside the inkjet head 10 to which ink, which is an example of a liquid, is supplied.

[0013] Furthermore, the inkjet head 10 includes components such as a circuit board 17 that controls the inkjet head 10 and a manifold 18 that forms part of the path between the inkjet head 10 and an ink tank.

[0014] The actuator base 11 includes a substrate 21, a pair of actuators 22, and a cover member 24.

[0015] The substrate 21 is formed in a rectangular plate shape from ceramics such as alumina. The substrate 21 has a flat mounting surface. A pair of actuators 22 are bonded to the mounting surface of the substrate 21. A supply hole 25 and a discharge hole 26 are formed in the substrate 21.

[0016] Pattern wiring 211 (electrode wiring) constituting electrodes is formed on the substrate 21 of the actuator base 11. The pattern wiring 211 is formed of, for example, a nickel thin film. The pattern wiring 211 has individual wiring 2111 and common wiring 2112, and is configured in a predetermined pattern shape connected to the electrode layer 34 formed on the actuator 22. For example, the individual wiring 2111 of the pattern wiring 211 is formed on the surface of the substrate 21 in an area outside two rows of actuators 22 arranged opposite each other in the extension direction. The common wiring 2112 is formed, for example, in an area inside a pair of actuators 22 arranged opposite each other in the extension direction, inside the supply hole 25, on the back surface of the substrate 21, etc.

[0017] Moreover, an insulating film 212 is formed on the substrate 21 of the actuator base 11. The insulating film 212 is formed, for example, on the pattern wiring 211 on the substrate 21. As an example, an adhesive is applied by spray coating or the like to form the insulating film 212.

[0018] The supply hole 25 is a through-hole that extends in the longitudinal direction of the actuators 22, between the pair of actuators 22, at the center of the substrate 21. The supply hole 25 communicates with the ink supply portion of the manifold 18. The supply hole 25 is connected to an ink tank via the ink supply portion. The supply hole 25 supplies ink from the ink tank to the ink chamber 27.

[0019] The discharge holes 26 are outlets for discharging ink. The discharge holes 26 are through-holes that penetrate the substrate 21, and a plurality of, for example, four, discharge holes 26 are provided. The discharge holes 26 communicate with the ink discharge portion of the manifold 18, and discharge the ink from the ink chambers 27.

[0020] A pair of actuators 22 is adhered to the mounting surface of the substrate 21. The pair of actuators 22 are arranged in two rows on the substrate 21 with a supply hole 25 sandwiched between them. Each actuator 22 is formed of two plate-shaped piezoelectric elements made of, for example, lead zirconate titanate (PZT). The two piezoelectric elements are bonded together so that their polarization directions are opposite to each other in the thickness direction. The actuators 22 are adhered to the mounting surface of the substrate 21 with, for example, a thermosetting epoxy adhesive.

[0021] The actuators 22 correspond to the two rows of nozzles 28 and are arranged in parallel inside the ink chamber 27. The actuators 22 divide the ink chamber 27 into a first common chamber 271 and two second common chambers 272.

[0022] The actuator 22 is formed to have a trapezoidal cross section. The longitudinal direction of the side surface 221 of the actuator 22 extends along the column direction, and has an inclined surface that is inclined with respect to the extension direction and the ejection direction. That is, the cross section of the actuator 22 perpendicular to the column direction is configured to have a trapezoidal shape. The top portion 222 of the actuator 22 is bonded to the nozzle plate 12. The actuator 22 includes a plurality of pressure chambers 31 and a plurality of dummy chambers 32. The actuator 22 has a plurality of side wall portions 33, and grooves that form the pressure chambers 31 and dummy chambers 32 are formed between the side wall portions 33. In other words, the side wall portions 33 are formed as drive elements between the grooves that form the pressure chambers 31 and dummy chambers 32.

[0023] 1 to 6, the bottom surface of the groove and the main surface of the substrate 21 are connected by inclined side surfaces 221. The pressure chambers 31 and dummy chambers 32 are arranged alternately. The pressure chambers 31 and dummy chambers 32 each extend in a direction intersecting the longitudinal direction of the actuator 22, and multiple pressure chambers 31 and dummy chambers 32 are arranged side by side in a first direction (X-axis in the drawings), which is the longitudinal direction of the actuator 22.

[0024] The shape of the pressure chamber 31 may be different from the shape of the dummy chamber 32. The side wall portion 33 is formed between the pressure chamber 31 and the dummy chamber 32, and changes the volume of the pressure chamber 31 by deforming in response to a drive signal.

[0025] The multiple pressure chambers 31 communicate with multiple nozzles 28 in the nozzle plate 12 joined to the top portion 222. Both ends of the pressure chambers 31 in the second direction communicate with the ink chambers 27. That is, one end opens to a first common chamber 271 of the ink chambers 27, and the other end opens to a second common chamber 272 of the ink chambers 27. Therefore, ink flows in from one end of the pressure chambers 31 and flows out from the other end. The pressure chambers 31 have throttling portions 240 whose openings at both ends in the second direction are partially blocked by the cover member 24, thereby increasing the flow path resistance. The throttling portions 240 increase the fluid resistance, for example, by reducing the cross-sectional area of ​​the flow path of the pressure chambers 31 perpendicular to the second direction compared to the inside of the pressure chambers 31. The throttling portions 240 are configured, for example, so that the width dimension in a direction intersecting the second direction, which is the extension direction of the pressure chambers 31, such as the first direction or the third direction, is narrowed at the inlets and outlets at both ends of the pressure chambers 31. For example, the throttle portion 240 is provided with a cover member 24 that closes the flow path of the pressure chamber 31, so that part of the flow path between the pressure chamber 31 and the ink chamber 27 is closed.

[0026] The dummy chamber 32 is closed on one side in the third direction by the nozzle plate 12 joined to the top portion 222, and is closed on both sides in the second direction by the cover member 24.

[0027] The cover member 24 has a cover plate 241 with a predetermined thickness. The cover plate 241 is attached to the side surface of the actuator 22. The cover plate 241 is formed with a plurality of throttle holes 242 as throttle openings that penetrate in the thickness direction. The cover members 24 are provided on both ends of the actuator 22 in the second direction, and close the openings of the dummy chambers 32 and also close part of the openings of the pressure chambers.

[0028] The grooves that form the pressure chambers 31 communicate with the first common chamber 271 and the second common chamber 272 via throttle holes 242 formed in the cover member 24. The throttle holes 242 are openings that are smaller than the cross-sectional area of ​​the pressure chambers, and as an example are configured as slit-shaped grooves that open to the nozzle plate 12 side.

[0029] The cover member 24 forms a throttle portion 240 having a greater fluid resistance than the pressure chamber 31 by closing a part of the opening that communicates with the first common chamber 271 and the second common chamber 272, which are common chambers at both ends of the pressure chamber 31.

[0030] The cover member 24 is joined to the inclined side surface 221 of the actuator 22. One edge of the cover member 24 may be joined to the substrate 21.

[0031] The cover member 24 is, for example, a plate material having a rectangular cross section, and one main surface of the plate material is attached so as to follow the side surface portion 221, which is an inclined surface, and a portion of the nozzle plate 12 side is removed by cutting or the like, so that the cover member 24 has, for example, a trapezoidal cross section with one side being inclined. Therefore, an end surface 244 on the substrate 21 side of the cover member 24 attached to the inclined side surface portion 221 of the actuator 22 is inclined with respect to the main surface of the substrate 21, and a gap G is formed between the end surface 244 on the substrate 21 side of the cover member 24 and the upper surface of the substrate 21. For example, the end surface 244 is inclined so that the outer side in the extension direction is away from the substrate 21, and the gap G is configured in a shape that widens outward in the extension direction.

[0032] The gap G is filled with adhesive BA. For example, the dimensions of the gap G are set to a dimensional condition that allows the adhesive BA to be drawn into the gap G by capillary action according to the physical properties of the adhesive BA, such as the viscosity, and that allows the filled adhesive BA to be held in the gap G until it hardens.

[0033] The adhesive BA is an insulating material and is formed, for example, from the same material as the insulating film 212 formed on the substrate 21. The adhesive BA is continuous with the insulating film 212 on the substrate 21 and forms a protective layer that protects the pattern wiring 211.

[0034] If the fluid resistance of the throttle portion 240 is made too large, the supply of ink to the pressure chamber 31 after the ink droplet is ejected will be slow, hindering higher speeds. The rise of the meniscus will differ depending on the ink viscosity, ejection volume, drive frequency, etc. Therefore, the thickness of the cover member 24 and the dimensions and position of the throttle hole 242 of the throttle portion 240 are set to provide a flow path resistance that corresponds to the ink supply conditions and the characteristics of the rise of the meniscus.

[0035] Both ends of the multiple dummy chambers 32 are closed by, for example, cover members 24. That is, cover members 24 are respectively arranged between the first common chamber 271 of the ink chamber 27 and the inlet of the dummy chamber 32, and between the outlet of the dummy chamber 32 and the second common chamber 272, and both ends of the dummy chamber 32 are separated from the ink chamber 27. For this reason, the dummy chamber 32 forms an air chamber into which ink does not flow.

[0036] An electrode layer 34 is provided in each of the pressure chambers 31 and dummy chambers 32 of the actuator base 11. The electrode layer 34 is formed, for example, from a nickel thin film. The electrode layer 34 extends from the bottom of the groove onto the substrate 21 and is connected to the pattern wiring 211. For example, the electrode layer 34 of the pressure chamber 31 is connected to the individual wiring 2111 on the mounting surface of the actuator base 11 and forms an individual electrode. The electrode layer 34 of the dummy chamber 32 is connected to the common wiring 2112 on the mounting surface of the actuator base 11 and forms a common electrode.

[0037] The nozzle plate 12 is formed of, for example, a rectangular film made of polyimide. The nozzle plate 12 faces the mounting surface of the actuator base 11. The nozzle plate 12 has a plurality of nozzles 28 formed therein, which penetrate the nozzle plate 12 in the thickness direction.

[0038] The nozzles 28 are provided in the same number as the pressure chambers 31 and are arranged opposite each pressure chamber 31. The nozzles 28 are aligned along the first direction and arranged in two rows corresponding to the pair of actuators 22. Each nozzle 28 is configured in a cylindrical shape with its axis extending in the third direction. For example, the nozzles 28 may have a constant diameter or may have a shape that narrows toward the center or tip. The nozzles 28 are arranged opposite to the midpoints of the pressure chambers 31 formed in the pair of actuators 22 in the extension direction and are each connected to the pressure chambers 31. One nozzle 28 is arranged in the longitudinal center of each pressure chamber 31.

[0039] The frame 13 is formed into a rectangular frame shape from, for example, a nickel alloy. The frame 13 is interposed between the mounting surface of the actuator base 11 and the nozzle plate 12. The frame 13 is bonded to both the mounting surface of the actuator base 11 and the nozzle plate 12. In other words, the nozzle plate 12 is attached to the actuator base 11 via the frame 13.

[0040] The manifold 18 is joined to the actuator base 11 on the side opposite to the nozzle plate 12. Inside the manifold 18, an ink supply portion, which is a flow path communicating with the supply hole 25, and an ink discharge portion, which is a flow path communicating with the discharge hole 26, are formed.

[0041] The circuit board 17 is a film carrier package (FCP). The circuit board 17 has a flexible resin film 51 on which a plurality of wirings are formed, and an IC 52 connected to the plurality of wirings of the film 51. The IC 52 is electrically connected to the electrode layer 34 via the wirings of the film 51 and the pattern wiring 211.

[0042] An ink chamber 27 is formed inside the inkjet head 10 configured as described above and is surrounded by the actuator base 11, the nozzle plate 12, and the frame 13. That is, the ink chamber 27 is formed between the actuator base 11 and the nozzle plate 12. For example, the ink chamber 27 is divided into three sections in the second direction by the two actuators 22, and has two second common chambers 272 as common chambers into which the discharge holes 26 open, and a first common chamber 271 as common chamber into which the supply hole 25 opens. The first common chamber 271 and the second common chamber 272 are in communication with a plurality of pressure chambers 31.

[0043] In the inkjet head 10 configured as described above, ink circulates between the ink tank and the ink chamber 27 through the supply hole, pressure chamber, and discharge hole. For example, in response to a signal input from the control unit of the inkjet printer, the drive IC 52 applies a drive voltage to the electrode layer 34 via the wiring of the film 51, thereby generating a potential difference between the electrode layer 34 of the pressure chamber 31 and the electrode layer 34 of the dummy chamber 32, thereby selectively deforming the side wall 33 in a shear mode. The volume of the pressure chamber 31 is changed by deforming the side wall 33 formed between the pressure chamber 31 and the dummy chamber 32 in response to the drive signal.

[0044] When the side wall portion 33 undergoes shear mode deformation, the volume of the predetermined pressure chamber 31 increases and the pressure decreases. As a result, ink in the ink chamber 27 flows into the pressure chamber 31.

[0045] With the volume of the pressure chamber 31 increased, the IC 52 applies a drive voltage of reverse potential to the electrode layer 34. This causes the side wall portion 33 to undergo shear mode deformation, reducing the volume of the pressure chamber 31 and increasing the pressure. This pressurizes the ink in the pressure chamber 31 and causes it to be ejected from the nozzle 28.

[0046] The method for manufacturing the inkjet head 10 will now be described. First, a plurality of piezoelectric members are attached to a plate-shaped substrate 21 with adhesive or the like, and then grooves are formed by machining using a dicing saw, slicer, or the like to form an actuator base 11 having a predetermined outer shape. Note that, for example, a block-shaped base member having a thickness equivalent to that of multiple sheets may be formed in advance and then divided to manufacture a plurality of actuator bases 11 of the predetermined shape.

[0047] Next, an electrode layer 34 and pattern wiring 211 are formed on the inner surfaces of the grooves that form the pressure chambers 31 and dummy chambers 32 and on the surface of the substrate 21. As a result, as shown in FIG. 8, the electrode layer 34 and pattern wiring 211 are formed in predetermined locations, and the actuators 22 that form the pressure chambers 31 and dummy chambers 32 are formed. Then, as shown in FIG. 6, a plate-shaped cover member 24 having multiple throttle holes 242 formed therein is bonded to the side surfaces 221 on both sides of the actuator 22 where the pressure chambers 31 and dummy chambers 32 open. For example, the cover member 24 is obtained by forming multiple throttle holes 242 that are narrower than the interiors of the pressure chambers 31 in a cover plate 241 that is formed in advance from an insulating material. The cover plate 241 is a molded part that is formed in a plate shape from a ceramic material such as zirconia or alumina, and slits that become the throttle holes 242, which have a flow path resistance greater than that of the ink chambers, are formed in the cover plate 241 by laser processing or machining.

[0048] As described above, by attaching the cover member 24, which has a plate-like shape and has a throttling hole 242 in advance, the opening of the dummy chamber 32 is covered, the opening of the pressure chamber 31 is partially covered, and the dummy chamber 32 is connected to the common chambers 271 and 272 by the throttling hole 242, which has a flow path cross-sectional area smaller than that of the inside of the pressure chamber 31.

[0049] The cover member 24 is formed by, for example, attaching a plate-like member having a rectangular cross section so that one main surface thereof fits along the inclined side surface portion 221, and then removing a portion of the cover member 24 on the nozzle plate 12 side by cutting or the like. Therefore, an end surface 244 on the substrate 21 side of the cover member 24 attached to the inclined side surface 221 of the actuator 22 is inclined with respect to the main surface of the substrate 21, and a gap G is formed between the end surface 244 on the substrate 21 side of the cover member 24 and the upper surface of the substrate 21. For example, the outer side of the end surface 244 in the extension direction is inclined so as to move away from the substrate 21, and the gap G is configured in a shape that widens outward in the extension direction.

[0050] Next, the gap G is filled with adhesive BA, an insulating material. Specifically, the adhesive BA is applied to a predetermined location slightly outside the gap G, and then left to stand for a predetermined time, allowing the adhesive BA to be drawn into the gap G by capillary action. For example, if the adhesive BA is applied over the entire surface, air bubbles will be trapped in the gap G, so the adhesive is supplied at intervals to allow the air bubbles to escape. For example, as shown in Figure 6, the adhesive is supplied by spot application at multiple supply points PA. For each gap G that is long in the X direction, for example, the supply points PA are arranged in multiple locations, for example, six locations, in each row within the gap G or near the entrance to the gap G.

[0051] 7 and 9, the adhesive BA is filled into gaps G formed in at least the portions of the substrate 21 where the individual electrodes are formed. For example, the adhesive BA may be filled into both gaps G on both sides of the actuator 22, or may be filled into only the gap G on one side where the individual electrodes are formed. Then, the adhesive BA is left to stand for a while until the adhesive fills due to capillary action, and then thermally cured to bake the adhesive BA in the gaps G.

[0052] Next, an insulating material, adhesive BA, is sprayed onto the electrode wiring 211 on the substrate 21 in an area outside the gap G to form an insulating film 212. Specifically, the adhesive BA is applied onto the electrode wiring 211 using a spray or the like, and then baked by thermal hardening. At this time, the insulating film 212 is continuous with the adhesive BA filled in the gap G, so that the electrode wiring 211 on the substrate 21, including the gap G, is protected by the insulating film 212 and adhesive BA. Note that the insulating film 212 may enter the gap G.

[0053] Furthermore, the actuator base 11 is assembled to the manifold 18, and the frame 13 is attached to one surface of the substrate 21 of the actuator base 11 with an adhesive sheet made of thermoplastic resin.

[0054] The assembled frame 13, the top 222 of the side wall portion 33 of the actuator 22, and the surface of the cover member 24 facing the nozzle plate 12 are polished to be flush with each other. The nozzle plate 12 is then attached by bonding to the polished surfaces of the top 222 of the side wall portion 33, the frame 13, and the cover member 24. At this time, the nozzles 28 are positioned so that they face the pressure chambers 31. Furthermore, as shown in FIG. 1, the driving IC chip 52 and the circuit board 17 are connected to the pattern wiring 211 formed on the main surface of the substrate 21 via a flexible printed circuit board, thereby completing the inkjet head 10.

[0055] An example of an inkjet printer 100 equipped with an inkjet head 10 will be described below with reference to Fig. 14. The inkjet printer 100 includes a housing 111, a medium supply unit 112, an image forming unit 113, a medium discharge unit 114, a conveying device 115, and a control unit 116.

[0056] The inkjet printer 100 is a liquid ejection device that performs an image formation process on a sheet of paper P by ejecting a liquid such as ink while transporting the sheet of paper P as a recording medium, which is the object of ejection, along a predetermined transport path A that runs from a medium supply section 112 through an image forming section 113 to a medium ejection section 114.

[0057] The housing 111 forms the outer shell of the inkjet printer 100. The housing 111 has an outlet at a predetermined location for discharging the paper P to the outside.

[0058] The medium supply unit 112 includes a plurality of paper feed cassettes, and is configured to be able to hold a stack of multiple sheets of paper P of various sizes.

[0059] The medium discharge unit 114 includes a paper discharge tray configured to be able to hold the paper P discharged from the discharge port.

[0060] The image forming section 113 includes a support section 117 that supports the paper P, and a plurality of head units 130 that are disposed above the support section 117 and face each other.

[0061] The support section 117 includes a conveyor belt 118 that is looped in a predetermined area where image formation is performed, a support plate 119 that supports the conveyor belt 118 from the back side, and a plurality of belt rollers 120 that are provided on the back side of the conveyor belt 118.

[0062] During image formation, the support unit 117 supports the paper P on a holding surface, which is the upper surface of the conveyor belt 118, and conveys the paper P downstream by moving the conveyor belt 118 at a predetermined timing by the rotation of the belt roller 120.

[0063] The head unit 130 includes a plurality of inkjet heads 10, ink tanks 132 as liquid tanks mounted on each inkjet head 10, a connection flow path 133 connecting the inkjet heads 10 and the ink tanks 132, and a circulation pump 134 as a circulation unit. The head unit 130 is a circulation type head unit that constantly circulates liquid in the ink tanks 132 and the pressure chambers 31, dummy chambers 32, and ink chambers 27 built inside the inkjet heads 10.

[0064] In this embodiment, the system includes inkjet heads 10 of four colors, cyan, magenta, yellow, and black, and ink tanks 132 that store ink of each color. The ink tanks 132 are connected to the inkjet heads 10 by connection flow paths 133. The connection flow paths 133 include a supply flow path that is connected to the supply port of the inkjet head 10, and a recovery flow path that is connected to the discharge port of the inkjet head 10.

[0065] A negative pressure control device such as a pump (not shown) is connected to the ink tank 132. The negative pressure control device controls the negative pressure inside the ink tank 132 in accordance with the head value between the inkjet head 10 and the ink tank 132, thereby causing the ink supplied to each nozzle 28 of the inkjet head 10 to form a meniscus of a predetermined shape.

[0066] The circulation pump 134 is a liquid feed pump configured, for example, as a piezoelectric pump. The circulation pump 134 is provided in the supply flow path. The circulation pump 134 is connected to a drive circuit of the control unit 116 by wiring, and is configured to be controllable by a CPU (Central Processing Unit). The circulation pump 134 circulates the liquid in the circulation flow path including the inkjet head 10 and the ink tank 132.

[0067] The conveying device 115 conveys the paper P along a conveying path A that runs from the medium supply unit 112 through the image forming unit 113 to the medium discharge unit 114. The conveying device 115 includes a plurality of guide plate pairs 121 and a plurality of conveying rollers 122 that are arranged along the conveying path A.

[0068] Each of the guide plate pairs 121 includes a pair of plate members arranged opposite each other with the paper P being conveyed therebetween, and guides the paper P along the conveying path A.

[0069] The conveying rollers 122 are driven to rotate under the control of the control unit 116, thereby sending the paper P downstream along the conveying path A. Sensors for detecting the conveying status of the paper are arranged at various points along the conveying path A.

[0070] The control unit 116 includes a control circuit such as a CPU which is a controller, a ROM (Read Only Memory) which stores various programs, a RAM (Random Access Memory) which temporarily stores various variable data and image data, and an interface unit which inputs data from the outside and outputs data to the outside.

[0071] In the inkjet printer 100 configured as described above, when the control unit 116 detects a print instruction entered by a user operating the operation input unit via an interface, for example, it drives the transport device 115 to transport the paper P and outputs a print signal to the head unit 130 at a predetermined timing, thereby driving the inkjet head 10. For the ejection operation, the inkjet head 10 sends a drive signal to the IC in response to an image signal corresponding to image data, applies a drive voltage to the electrode layer 34 of the actuator 22 via wiring, and selectively drives the side wall portion 33 of the actuator 22 to eject ink from the nozzles 28, thereby forming an image on the paper P held on the transport belt 118. For the liquid ejection operation, the control unit 116 drives the circulation pump 134 to circulate liquid through a circulation flow path that passes through the ink tank 132 and the inkjet head 10. By the circulation operation, the ink in the ink tank 132 is supplied from the supply hole 25 to the first common chamber 271 of the ink chamber 27 through the ink supply portion of the manifold 18 by driving the circulation pump 134. This ink is supplied to the multiple pressure chambers 31 and multiple dummy chambers 32 of the pair of actuators 22. The ink flows into the second common chamber 272 of the ink chamber 27 through the pressure chambers 31 and dummy chambers 32. This ink is discharged from the discharge hole 26 to the ink tank 132 through the ink discharge portion of the manifold 18.

[0072] According to the above-described embodiment, a protective layer can be formed by drawing the adhesive BA by capillary action into the gap G below the cover member 24 disposed on the side wall of the actuator 22. That is, for example, when an insulating film made of adhesive is sprayed onto the electrode-forming surface of the head substrate by a spray or the like, the cover plate 241 acts as a canopy and the pattern wiring, which is the electrode wiring, cannot be insulated and protected in the gap G, but insulation can be easily ensured by drawing the dimensions of the gap G by capillary action.

[0073] Furthermore, by making the gap G large enough to draw in and retain adhesive through capillary reduction, an insulating section can be reliably formed and the pattern wiring can be insulated and protected. Therefore, when conductive ink is filled into the head 10 and voltage is applied, the conductive material in the ink can be prevented from precipitating on the pattern wiring, causing the pattern wiring to short-circuit.

[0074] Furthermore, the above-described embodiment can provide an inkjet head with high frequency characteristics. That is, in the inkjet head 10 according to the above embodiment, by providing the cover member 24 on the pressure chamber 31, the inlet and outlet of the pressure chamber 31 have higher flow path resistance than the interior of the pressure chamber 31, the first common chamber 271, and the second common chamber 272. As a specific example, the openings that open to the first common chamber 271 and the second common chamber 272, which are common chambers of the pressure chamber 31, are smaller than the flow path cross-sectional area of ​​the pressure chamber 31. This reduces the rise of the meniscus when liquid is ejected from the inkjet head 10. This speeds up the recovery of the meniscus, reducing the impact on the next droplet and improving ejection stability.

[0075] Figure 10 shows Test Example 1 for an inkjet head 110 equipped with a throttling (throttle section 240), and Test Example 2 for an inkjet head 1010 equipped with no throttling. Figure 11 shows the frequency characteristics of the inkjet head 110 equipped with a throttling according to Test Example 1, and Figure 12 shows the frequency characteristics of the inkjet head 1010 equipped with no throttling as Comparative Example 2. Figures 11 and 12 each show the relationship between nozzle ejection speed and frequency for 1 drop and 3 drops, respectively.

[0076] The inkjet heads 110 and 1010 according to Test Examples 1 and 2 are side shooter inkjet heads in which both sides of the pressure chambers 31 in the second direction, which is the extension direction, are connected to a common chamber, and the nozzles 28 open midway in the extension direction of the pressure chambers 31. The inkjet heads 110 and 1010 according to Test Examples 1 and 2 are provided with a plurality of pressure chambers 31, each having an electrode layer 34 formed on its inner wall surface, and a plurality of dummy chambers 32, arranged alternately, and both ends of the dummy chambers 32 in the extension direction are closed by cover members 24.

[0077] As shown in FIG. 12, the inkjet head 1010 according to Test Example 2 has a flat ejection speed in the low-frequency range but tends to decrease as the frequency increases, resulting in a difference in ejection speed between the low-frequency range and the high-frequency range. For the inkjet head 1010 according to Test Example 2, the ejection speed is flat up to 25 kHz, but tends to decrease as the frequency increases above 25 kHz. For the inkjet head 1010 according to Test Example 2, the ejection speed is flat up to 15 kHz, but tends to decrease as the frequency increases above 15 kHz. Therefore, the impact position varies depending on the print pattern. Such a large difference in ejection speed makes it difficult to drive at high speeds because it takes time for the meniscus to settle, resulting in a decrease in print quality.

[0078] 11, in the inkjet head 110 having the throttle portion 240, the ejection speed tends to be flat for both 1 drop and 3 drops. This is because the fluid resistance between the nozzles increases due to the common liquid, and the rise of the meniscus decreases.

[0079] FIG. 13 also shows the results of a simulation of meniscus recovery for Test Example 1, in which a pressure chamber is provided with a throttle, and Test Example 2, in which a throttle is not provided. As shown in FIG. 13, when the nozzle meniscus is low-frequency, there is sufficient time between the ejection of an ink droplet and the ejection of the next droplet, allowing stable ejection after waiting for the meniscus to recover, regardless of whether a throttle is provided. On the other hand, when the nozzle is high-frequency, the time between the ejection of a dot (ink droplet) and the ejection of the next droplet is short, so the ejection of the next droplet begins before the meniscus recovers. Therefore, in the inkjet head 1010 without a throttle, the meniscus rises significantly after ejection, preventing it from recovering in time for the next droplet to be ejected, resulting in a slower ejection speed. In contrast, when a throttle is provided, the meniscus rises less, allowing the meniscus to recover more quickly, reducing the impact on the next droplet. Therefore, these simulation results suggest that providing a throttle between the pressure chamber 31 and the common chamber improves the ejection stability of the inkjet head 110.

[0080] Furthermore, in the above embodiment, by attaching the cover member 24 with a pre-formed throttle opening to the actuator 22, the number of assembly steps is reduced and a precise throttle opening can be easily formed.

[0081] [Second embodiment] The configuration of an inkjet head 20, which is a liquid ejection head according to the second embodiment, will be described below with reference to Figures 1 to 5, 15, and 16. Figure 15 is a cross-sectional view showing the configuration of an actuator base 11 of the inkjet head 20 according to the second embodiment, and Figure 16 is a cross-sectional view showing the configuration of a substrate 21 and an actuator 22.

[0082] The inkjet head 20 of this embodiment is configured such that a portion of the cover member 24 is embedded in the substrate 21, and differs from the inkjet head 10 of the first embodiment in that the substrate 21 has a groove in which the end of the cover member 24 is disposed. However, other than the arrangement of the cover member 24 and the substrate 21, the configuration is the same as that of the inkjet head 10 of the first embodiment.

[0083] As shown in FIGS. 1 to 5, the inkjet head 20 includes an actuator base 11, a nozzle plate 12, and a frame 13.

[0084] The actuator base 11 includes a substrate 21, a pair of actuators 22, and a cover member 24.

[0085] The substrate 21 is formed in a rectangular plate shape from ceramics such as alumina. The substrate 21 has a flat mounting surface. A pair of actuators 22 are bonded to the mounting surface of the substrate 21. The substrate 21 also has a supply hole 25 and a discharge hole 26 formed therein.

[0086] Accommodating grooves 213 are formed in the portions of the substrate 21 where the actuator 22 is mounted and in portions facing both side edges of the actuator 22. The accommodating grooves 213 are recesses that extend in the X direction and follow the outline of the edge portions of the cover plate 241. For example, the accommodating grooves 213 are V-shaped grooves, and the groove bottoms are configured at 90 degrees following the shape of the corner portions 246 of the cover plate 241. The corner portions 246 of the cover plate 241 are embedded in the accommodating grooves 213.

[0087] Furthermore, pattern wiring 211 is formed on the substrate 21. The pattern wiring 211 is formed in a predetermined region including the V-shaped groove bottom surface of the accommodation groove 213 of the substrate 21. The pattern wiring 211 has individual wiring 2111 and common wiring 2112, and is configured in a predetermined pattern shape connected to the electrode layer 34 formed on the actuator 22.

[0088] The actuator 22 is formed to have a trapezoidal cross section. A side surface 221 of the actuator 22 has an inclined surface that is inclined with respect to the second direction and the third direction. That is, the cross section of the actuator 22 that is perpendicular to the second direction is configured to have a trapezoidal shape. A top portion 222 of the actuator 22 is bonded to the nozzle plate 12. The actuator 22 includes a plurality of pressure chambers 31 and a plurality of dummy chambers 32. The actuator 22 has a plurality of side wall portions 33, and grooves that form the pressure chambers 31 and dummy chambers 32 are formed between the side wall portions 33. In other words, the side wall portions 33 are formed as drive elements between the grooves that form the pressure chambers 31 and dummy chambers 32.

[0089] The cover member 24 has a cover plate 241 with a predetermined thickness. The cover plate 241 is configured in a shape corresponding to the inclined side surface portion 221 of the actuator, for example, a rectangular shape extending in the first direction. The cover plate 241 is formed with throttle holes 242 as a plurality of throttle openings that penetrate in the thickness direction. The cover members 24 are provided on both ends of the actuator 22 in the second direction, and close the openings of the dummy chambers 32 and also close part of the openings of the pressure chambers.

[0090] The grooves that form the pressure chambers 31 communicate with the first common chamber 271 and the second common chamber 272 via throttle holes 242 formed in the cover member 24. The throttle holes 242 are openings that are smaller than the cross-sectional area of ​​the pressure chambers, and as an example are configured as slit-shaped grooves that open to the nozzle plate 12 side.

[0091] The cover member 24 forms a throttle portion 240 having a greater fluid resistance than the pressure chamber 31 by closing a part of the opening that communicates with the first common chamber 271 and the second common chamber 272, which are common chambers at both ends of the pressure chamber 31.

[0092] The cover member 24 is joined to the inclined side surface portion 221 of the actuator 22. A portion of the edge portion of the cover member 24 on the substrate 21 side is embedded in the accommodation groove 213 of the substrate 21. At least one corner portion 246 of the cover plate 241 is accommodated in the accommodation groove 213, and in this embodiment, the entire surface of the end face 244 on the substrate 21 side is disposed in the accommodation groove 213. Therefore, the outer main surface of the cover plate 241 and the mounting surface of the substrate 21 form an outer surface that is continuous at an obtuse angle.

[0093] For example, the cover member 24 is formed by attaching one main surface of a plate material having a rectangular cross section along the side surface portion 221, which is an inclined surface, and removing a portion of the nozzle plate 12 side by cutting or the like, to form a trapezoidal cross section with a slope on one side. In this embodiment, an end surface 244 of the cover plate 241 on the substrate 21 side is embedded in the accommodation groove 213 from one corner portion 246 to the other corner portion 247, so that an outer main surface 245 of the cover plate 241 and the upper surface of the substrate 21 form a continuous outer surface.

[0094] In this embodiment, an insulating film 212 may be formed on the substrate 21 of the actuator base 11. The insulating film 212 is formed, for example, on the pattern wiring 211 on the substrate 21. As an example, an adhesive is applied by spray coating or the like to form the insulating film 212.

[0095] The method of manufacturing the inkjet head 20 will now be described. First, a plurality of piezoelectric members are attached to a plate-shaped substrate 21 with adhesive or the like, and then machining is performed using a dicing saw, slicer, or the like to form grooves to form the actuators 22, and a housing groove 213 is formed in the substrate 21, thereby forming an actuator base 11 having a predetermined outer shape. Note that, for example, a block-shaped base member having a thickness equivalent to that of multiple plates may be formed in advance and then divided to manufacture a plurality of actuator bases 11 of the predetermined shape.

[0096] Next, an electrode layer 34 and pattern wiring 211 are formed on the inner surfaces of the grooves that form the pressure chambers 31 and dummy chambers 32 and on the surface of the substrate 21. As a result of the above, the electrode layer 34 and pattern wiring 211 are formed in predetermined locations, and the actuators 22 that form the pressure chambers 31 and dummy chambers 32 are formed. A plate-shaped cover member 24 having multiple throttle holes 242 formed therein is adhered to the side surfaces 221 on both sides of the actuator 22 where the pressure chambers 31 and dummy chambers 32 open. For example, the cover member 24 is obtained by forming multiple throttle holes 242 that are narrower than the interiors of the pressure chambers 31 in a cover plate 241 that is formed in advance in a plate shape from an insulating material. The cover plate 241 is a mold part formed in a plate shape from a ceramic material such as zirconia or alumina, and slits that become the throttle holes 242, which have a flow path resistance greater than that of the ink chambers, are formed in the cover plate 241 by laser processing or machining.

[0097] As described above, by attaching the cover member 24, which has a plate-like shape and has a throttling hole 242 in advance, the opening of the dummy chamber 32 is covered, the opening of the pressure chamber 31 is partially covered, and the dummy chamber 32 is connected to the common chambers 271 and 272 by the throttling hole 242, which has a flow path cross-sectional area smaller than that of the inside of the pressure chamber 31.

[0098] At this time, positioning can be easily achieved by placing the corner portion 246 of the cover plate 241 in the accommodation groove 213.

[0099] Next, adhesive BA, which is an insulating material, is sprayed onto the pattern wiring 211 on the substrate 21 to form an insulating film 212. Specifically, adhesive BA is applied onto the pattern wiring 211 using a spray or the like, and then baked.

[0100] Furthermore, the actuator base 11 is assembled to the manifold 18, and the frame 13 is attached to one surface of the substrate 21 of the actuator base 11 with an adhesive sheet made of thermoplastic resin.

[0101] The assembled frame 13, the top 222 of the side wall portion 33 of the actuator 22, and the surface of the cover member 24 facing the nozzle plate 12 are polished to be flush with each other. The nozzle plate 12 is then attached by bonding to the polished surfaces of the top 222 of the side wall portion 33, the frame 13, and the cover member 24. At this time, the nozzles 28 are positioned so that they face the pressure chambers 31. Furthermore, as shown in FIG. 1, the driving IC chip 52 and the circuit board 17 are connected to the pattern wiring 211 formed on the main surface of the substrate 21 via a flexible printed circuit board, thereby completing the inkjet head 20.

[0102] According to the inkjet head 20 of this embodiment, the substrate 21 is formed with an accommodation groove 213 that accommodates at least one corner portion 246 of the cover plate 241, thereby making it possible to make the outer main surface 245 of the cover member 24 continuous with the upper surface of the substrate 21. In other words, it is possible to prevent gaps or recesses from being formed between the substrate 21 and the cover plate 241. Therefore, the insulating film 212 formed by spray coating can insulate and protect the electrodes, preventing short-circuiting of the electrodes.

[0103] Furthermore, since the accommodation groove 213 is formed, the positioning of the cover plate 241 becomes easy, and the positioning accuracy of the member can be improved.

[0104] The present invention is not limited to the above-described embodiment, and in the implementation stage, the components can be modified and embodied without departing from the spirit of the invention.

[0105] For example, in the above embodiment, the cover member 24 is illustrated as having a plurality of throttle holes 242 formed in the cover plate 241, but the present invention is not limited to this. For example, the cover member 24 may be configured as a throttle section 240 that has higher fluid resistance than the pressure chamber 31. For example, in another embodiment, the throttle opening may be formed by a plurality of holes.

[0106] Furthermore, the number of nozzle rows is not limited to that in the above embodiment, and the configuration may include one row, or three or more rows.

[0107] Furthermore, the actuator 22 may be a single piezoelectric element instead of two piezoelectric elements. The dummy chamber 32 may be connected to the common chambers, i.e., the first common chamber 271 and the second common chamber 272. The supply side and the discharge side may be reversed, or may be configured to be switchable.

[0108] Furthermore, in the above embodiment, as an example, a circulation-type inkjet head is exemplified, in which one side of the pressure chamber 31 is the supply side and the other side is the discharge side, and fluid flows in from one side of the pressure chamber and flows out from the other side. However, the present invention is not limited to this. For example, a common chamber on both sides of the pressure chamber 31 may be the supply side, and fluid may flow in from both sides. That is, a configuration may be possible in which fluid flows in from both sides of the pressure chamber 31 and flows out from the nozzle 28 located in the center of the pressure chamber 31. Even in this case, by providing a throttle portion 240 at the inlet portion on both sides of the pressure chamber 31, fluid resistance can be increased and ejection efficiency can be improved.

[0109] For example, the liquid to be ejected is not limited to ink for printing, but may be a device that ejects a liquid containing conductive particles for forming pattern wiring on a printed wiring board.

[0110] For example, in the second embodiment, an example was shown in which the entire end face 244 was disposed in the housing groove 213, but this is not limiting. For example, a portion may be disposed on the substrate 21. Even in this case, the gap is smaller than when the housing groove 213 is not present, and therefore, depending on the dimensions, an insulating film for protecting the electrode can be formed.

[0111] Furthermore, in the above embodiment, the inkjet head is used in a liquid ejection device such as an inkjet printer, but the invention is not limited to this and can also be used in, for example, 3D printers, industrial manufacturing machines, and medical applications, allowing for reductions in size, weight, and cost.

[0112] According to at least one of the embodiments described above, it is possible to provide a liquid ejection head manufacturing method, a liquid ejection head, and a liquid ejection apparatus that facilitate insulation protection of electrode wiring.

[0113] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0114] 10...inkjet head, 11...actuator base, 12...nozzle plate, 13...frame, 17...circuit board, 18...manifold, 21...substrate, 22...actuator, 24...cover member (wall portion), 25...supply hole, 26...discharge hole, 27...ink chamber, 31...pressure chamber, 32...dummy chamber, 33...side wall portion, 34...electrode layer, 51...film, 52...driving IC chip, 100...inkjet printer, 111...casing, 112...medium supply unit, 113...image forming unit, 11 4...medium discharge section, 115...conveying device, 116...control section, 117...support section, 118...conveying belt, 119...support plate, 120...belt roller, 121...pair of guide plates, 122...conveying roller, 130...head unit, 132...ink tank, 133...connecting flow path, 134...circulation pump, 211...pattern wiring, 221...side section, 222...top, 240...throttling section, 241...cover plate, 242...throttling hole (throttle opening), 271...first common chamber, 272...second common chamber.

Claims

1. a substrate having an electrode on its surface; an actuator provided on the surface of the substrate and having a plurality of pressure chambers communicating with nozzles that eject liquid; a cover member joined to a side surface of the actuator, the cover member having throttle openings at positions facing the pressure chambers and having a higher fluid resistance than the interiors of the pressure chambers; an insulating material filled in a gap formed between the surface of the substrate and the cover member; an insulating film covering the electrodes on the substrate; A liquid ejection head comprising:

2. a side surface of the actuator inclined with respect to a surface of the substrate; the cover member is a plate-shaped member, The liquid ejection head according to claim 1 , wherein the insulating material is filled in the gaps formed in at least the portions of the substrate where the individual electrodes are formed.

3. a cover member having a throttle opening with a higher fluid resistance than the interior of the pressure chambers at a position facing the ends of the pressure chambers on a side surface of the actuator, the actuator being disposed on a substrate on which electrodes are formed, and having a plurality of pressure chambers communicating with nozzles that eject liquid; filling a gap formed between the substrate and the cover member with an insulating material; A method for manufacturing a liquid ejection head, comprising:

4. supplying an insulating material into or near a gap formed between the substrate and the cover member, and allowing a predetermined time to pass, thereby filling the gap with the insulating material; After the gap is filled with the insulating material, an insulating film is formed by supplying the insulating material onto the substrate on which the electrodes are formed. The method for manufacturing a liquid ejection head according to claim 3 .

5. A substrate; an actuator provided on the surface of the substrate and having a plurality of pressure chambers communicating with nozzles that eject liquid; a cover member joined to a side surface of the actuator, the cover member having openings at positions facing the pressure chambers, the openings having a higher fluid resistance than the interiors of the pressure chambers; a receiving groove in which an end portion of the cover member is placed is formed in a surface of the substrate at a position facing both side portions of the actuator; Liquid ejection head.

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