Liquid ejection head and recording device

Abstract

To provide a liquid head that is able to decrease a driving voltage for obtaining a proper amount of displacement of a vibration plate and that is suitable for sucking or wiping liquid.SOLUTION: A liquid ejection head 100 includes a first substrate 2 and a second substrate 3. An ejection port 6 for ejecting liquid is provided in a flat first surface 5a of the first substrate 2. A driving element is provided on a second surface of the substrate 2. A second substrate 3 is bonded to the second surface 5b of the first substrate 2 and forms a pressure chamber 8 to which liquid is supplied. In the first substrate 2, a portion forming the pressure chamber 8 forms a vibration plate 7, and the liquid in the pressure chamber 8 is ejected from the ejection port 6 by displacement of the vibration plate 7. The second surface 5b of the first substrate 2 has an uneven shape including the driving element. In the vibration plate 7, rigidity of a second region surrounding a first region is lower than rigidity of the first region in which the ejection port 6 is provided.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a liquid ejection head capable of ejecting liquid such as ink, and a recording apparatus. [Background technology]

[0002] In recent years, liquid ejection heads with ejection ports arranged at high density are required for inkjet recording devices in order to meet the demands of high-definition images and high-speed recording. In response to such demands, among liquid ejection heads using piezoelectric elements, bend-mode liquid ejection heads are widely used because it is relatively easy to arrange the piezoelectric elements at high density and with high precision. In bend-mode liquid ejection heads, the inner walls of the pressure chambers are formed by a laminated structure consisting of a piezoelectric element and a vibration plate, and pressure is generated in the pressure chambers by applying a voltage to deform the piezoelectric element in an in-plane direction and deform (bend) the vibration plate in an out-of-plane direction.

[0003] Patent Document 1 and Patent Document 2 disclose a bend mode type liquid ejection head. In the liquid ejection head disclosed in Patent Document 1, a substrate on which an ejection port (nozzle) is formed is disposed so as to block a pressure chamber, and the area of ​​the substrate that is not fixed to the wall of the pressure chamber becomes a vibration plate. An electrode and a piezoelectric element are formed on the surface of the substrate that constitutes this vibration plate, and liquid is ejected from the ejection port by deformation of the piezoelectric element.

[0004] Patent Document 2 also shows a nozzle plate in which a first electrode, a piezoelectric element, and a second electrode are formed on a substrate on which ejection ports (nozzles) are formed, and a metal material is formed on the second electrode so as to cover the entire substrate. A bend mode type liquid ejection head is formed by bonding the metal material side of this nozzle plate to one side of a base material on which openings that become pressure chambers are formed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2014-172323 A [Patent Document 2] JP 2012-71587 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the configuration of Patent Document 1, electrodes and piezoelectric elements are formed on the surface opposite to the pressure chamber in which the nozzle is formed, resulting in unevenness on the surface of the substrate. For this reason, a protective film and a water-repellent film are formed to fill in the unevenness, and the surface of the substrate is formed into a flat surface shape. This makes it possible to bring the cap member into close contact with the surface of the substrate, enabling a suction operation to suck ink from the surface side of the substrate. In addition, it becomes possible to properly perform a wiping operation to wipe off ink and dust attached to the surface of the substrate with a wiper. However, when a protective film and a water-repellent film are formed on the surface of the diaphragm, the diaphragm becomes thicker and is less likely to be displaced. On the other hand, in Patent Document 2, although unevenness does not occur on the surface of the diaphragm, the diaphragm becomes hard and the amount of displacement becomes smaller because the entire diaphragm is covered with a metal material.

[0007] As described above, the techniques described in Patent Documents 1 and 2 are configured such that the diaphragm is difficult to displace, and in order to obtain a sufficient amount of displacement in the diaphragm, it is necessary to apply a large drive voltage to the piezoelectric element.

[0008] The present disclosure aims to provide a liquid head that makes it possible to reduce the drive voltage required to obtain an appropriate amount of displacement in the vibration plate, and that is suitable for suctioning liquid and wiping operations, and a recording device using the same. [Means for solving the problem]

[0009] The present disclosure provides a liquid ejection head comprising: a first substrate having an ejection port for ejecting liquid provided on a flat first surface and having a driving element provided on a second surface opposite the first surface; and a second substrate joined to the second surface of the first substrate and forming a pressure chamber configured to be supplied with liquid between the second surface of the first substrate, wherein a portion of the first substrate forming the pressure chamber forms a vibration plate that is displaced by the driving element, and the vibration plate is displaced to eject liquid in the pressure chamber from the ejection port, wherein the second surface of the first substrate has an uneven shape including the driving element, and the vibration plate has a lower rigidity in a second region surrounding the first region than in a first region in which the ejection port is provided. Effect of the Invention

[0010] According to the present disclosure, it is possible to reduce the driving voltage required to obtain an appropriate amount of displacement in the vibration plate, and it is also possible to provide a liquid head that is suitable for suctioning liquid and wiping operations, and a recording device equipped with the same. [Brief description of the drawings]

[0011] [Figure 1] 1A and 1B are a schematic diagram and a block diagram showing a control configuration of an inkjet recording apparatus. [Diagram 2] 1 is a perspective view showing an overall configuration of a liquid ejection head according to an embodiment. [Diagram 3] FIG. 2 is an exploded perspective view showing an enlarged view of a portion of a substrate of the liquid ejection head. [Figure 4] 4 is a cross-sectional view taken along line IVa-IVa in FIG. 3 and a plan view of a region F shown in FIG. [Diagram 5] 4 is an enlarged cross-sectional view showing a portion of a substrate in a first comparative example. FIG. [Figure 6] FIG. 11 is an enlarged cross-sectional view showing a portion of a substrate in a second comparative example. [Figure 7] 5 is an enlarged cross-sectional view showing a part of a substrate in a modified example of the first embodiment. FIG. [Figure 8]FIG. 8 is a diagram showing the displacement volume of a compression chamber per unit voltage of each of the substrates in FIGS. 4 to 7. [Figure 9] FIG. 11 is an exploded perspective view showing an enlarged view of a portion of a substrate in a second embodiment. [Figure 10] 10 is a cross-sectional view taken along line XX in FIG. 9. [Figure 11] FIG. 11 is an enlarged cross-sectional view showing a part of a substrate in a modified example of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the present invention according to the claims, and not all of the combinations of features described in the present embodiments are necessarily essential to the solutions of the present disclosure. In addition, the following describes an inkjet head that ejects ink as a liquid among liquid ejection heads to form an image, but the liquid ejection head of the present disclosure can also be applied to ejecting liquids other than ink.

[0013] (First embodiment) FIG. 1A is a schematic diagram of an inkjet recording apparatus 700 (hereinafter, simply referred to as the recording apparatus 700) in this embodiment. As shown in FIG. 1A, a sheet-like recording medium 703 is conveyed in the X direction by a conveying means 702, and passes under a recording unit 701 at a predetermined speed. The recording unit 701 is mainly composed of a liquid ejection head 100, which will be described later. The liquid ejection head 100 has a plurality of ejection ports that eject ink, which is a liquid containing coloring material, as droplets, arranged in a range corresponding to the width of the recording medium along a direction (Y direction) that intersects (orthogonal in this embodiment) the conveying direction of the recording medium. When the recording medium 703 passes under the liquid ejection head 100, ejection elements, which will be described later and are provided corresponding to each ejection port of the liquid ejection head 100, are driven according to ejection data, and ink is ejected from the ejection ports in the Z direction toward the recording medium to record an image. In this manner, the printing apparatus 700 in this embodiment is a full-line type printing apparatus that performs printing by ejecting ink from an array of ejection ports arranged along the width direction (Y direction) of the printing medium 703 while continuously transporting the printing medium 703.

[0014] FIG. 1B is a block diagram showing the control configuration of the printing apparatus in this embodiment and the second embodiment described later. The printing apparatus 700 includes a CPU 500, a ROM 501, and a RAM 502. The CPU 500 uses the RAM 502 as a work area according to a program stored in the ROM 501 and controls each part of the printing apparatus 700 in an integrated manner. For example, the CPU 500 performs a predetermined image processing on image data received from an externally connected host device 600 according to a program and parameters stored in the ROM 501, and generates ejection data for driving a driving element of the liquid ejection head 100. The CPU 500 drives the liquid ejection head 100 according to the ejection data, and ejects ink at a predetermined frequency. The CPU 500 also drives a conveying motor 503 provided on a conveying means 702 at a speed corresponding to the ejection frequency of the ejection operation by the liquid ejection head 100, and conveys the recording medium 703 in the X direction. As a result, an image corresponding to the image data received from the host device 600 is recorded on the recording medium 703.

[0015] The liquid sending unit 504 is a unit for supplying liquid (ink) to the liquid ejection head 100. The liquid sending unit 504 controls a pressure control unit and a switching mechanism provided therein under the management of the CPU 500, and controls the flow of ink in an ink flow path including the liquid ejection head 100. The liquid sending unit 504 may function as a liquid supply unit that supplies ink to the liquid ejection head 100, or may have a function as a liquid circulation unit that circulates ink in an ink circulation path including the liquid ejection head 100. When the liquid sending unit 504 has a function as a liquid circulation unit (circulation means), the liquid sending unit 504 supplies ink to the liquid ejection head 100 and collects ink from the liquid ejection head 100.

[0016] The recovery unit 505 is a unit that performs processing for maintaining and recovering the discharge performance of the liquid (ink) in the liquid discharge head 100, and is controlled by the CPU 500. The recovery unit 505 includes a suction means that forcibly sucks the liquid from the discharge ports of the liquid discharge head 100 that discharge the liquid, and a wiping means that performs a wiping operation to wipe off foreign matter such as minute droplets and dust attached to the surface of the liquid discharge head 100. The suction means includes a cap member that is provided so as to be able to be in close contact with or separate from the surface of the liquid discharge head, and a negative pressure generating means that is connected to the cap member. By driving the negative pressure generating means while the cap member is in close contact with the surface of the discharge head 100, a suction operation can be performed to forcibly suck in the gas and liquid in the liquid discharge head 100 from the discharge ports. This suction operation is performed in a filling operation that fills the pressure chambers and discharge ports of the liquid discharge head 100 with liquid, a suction recovery operation that discharges the thickened liquid (ink) generated in the discharge ports and replaces it with a liquid (ink) suitable for discharge, and the like. The wiping means is composed of a wiper that moves while in contact with the surface of the liquid ejection head 100, and a wiper drive means that moves the wiper. By using the wiper drive means to move the wiper while in contact with the surface of the liquid ejection head 100, it becomes possible to wipe away foreign matter adhering to the surface of the liquid ejection head 100.

[0017] 2 is a perspective view showing the overall configuration of the liquid ejection head 100. The liquid ejection head 100 includes a substrate 1, an electric wiring substrate 102 electrically connected to the substrate 1 via a flexible wiring substrate 101, a power supply terminal 103 for controlling the ejection of ink (liquid), and an input terminal 104 to which a control signal or the like is input. As a method of supplying ink to the liquid ejection head 100, for example, a method of supplying ink from an ink tank provided on the upstream side of the liquid ejection head 100 to a pressure chamber in the liquid ejection head 100 using capillary action or a pump. In addition, there is also a method of supplying ink to a pressure chamber of the liquid ejection head 100 by providing ink tanks in each of the flow paths on the upstream side and the downstream side of the liquid ejection head 100 and flowing ink from one ink tank to the other ink tank.

[0018] In the liquid ejection head 100, a plurality of substrates 1 are arranged along the Y direction. A plurality of ejection ports are arranged at high density on each substrate 1, and the ejection ports are configured to obtain a recording width of 20 mm in the Y direction. The liquid ejection head 100 in this embodiment is a long full-line type inkjet head in which a plurality of substrates 1 are arranged along the Y direction to accommodate recording media such as A4 size. By arranging the plurality of substrates 1, an ejection port row that is longer than the width of an A4 size recording medium is formed in the liquid ejection head 100 along the Y direction.

[0019] Here, the configuration of the substrate 1 constituting the liquid ejection head 100 in this embodiment will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is an exploded perspective view showing an enlarged portion of the substrate 1 constituting the liquid ejection head 100. Fig. 4(a) is a cross-sectional view of the substrate 1 shown in Fig. 3 taken along line IVa-IVa, and Fig. 4(b) is a plan view of an area F surrounded by a dashed line in the substrate in Fig. 3(a) as viewed from the surface 5a (first surface) of the first substrate 2. For convenience of illustration, Fig. 4(b) shows a planar shape of the substrate 1 shown in Fig. 4(a) excluding the base substrate 15.

[0020] For simplicity, Fig. 3 shows a configuration in which five ejection ports 6 are arranged on the substrate 1 along the Y direction. However, in reality, 120 ejection ports 6 are arranged at intervals of 150 dpi (169.3 um) in the Y direction, and eight ejection port rows consisting of these ejection ports are arranged at intervals of 1000 um in the X direction. By shifting each of the eight ejection port rows by 1200 dpi (21.2 um) in the Y direction, the ejection ports 6 can be arranged at a high density in the Y direction. However, the arrangement of the ejection ports 6 is not limited to this.

[0021] The configuration of the substrate 1 will be described with reference to Figures 3 and 4. The substrate 1 includes a first substrate 2, a second substrate 3, and a third substrate 4. These three substrates 2, 3, and 4 are bonded together by an adhesive 10 in a stacked state as shown in Figure 4. In Figures 3 and 4, the upper surface of each of the substrates 2, 3, and 4 is also referred to as the front surface, and the lower surface is also referred to as the back surface.

[0022] As shown in FIG. 3, the first substrate 2 has ejection ports 6 formed therethrough. The second substrate 3 has recesses (first recesses) 8a for forming pressure chambers 8 (see FIG. 4) at positions corresponding to the ejection ports 6, and the recesses 8a have first openings (pressure chamber openings) 9 formed therein so as to penetrate the second substrate 3. By bonding the front surface of the second substrate 3 to the rear surface of the first substrate 2 with an adhesive 10, a space is formed between the first substrate 2 and the second substrate 3 as shown in FIG. 4(a), and this space becomes the pressure chamber 8. In the example shown in FIG. 3 and FIG. 4, five ejection ports 6 are formed in the first substrate 2, and thus five pressure chambers 8 are formed corresponding to the ejection ports 6, and each pressure chamber 8 is connected to each ejection port 6. The portion where the first substrate 2 and the second substrate 3 are bonded becomes a partition wall of the pressure chamber 8, and the inner region surrounded by this partition wall, i.e., the region constituting the upper inner wall of the pressure chamber 8, constitutes a displaceable vibration plate 7.

[0023] The third substrate 4 is formed with a recess (second recess) 50a for forming a first common flow path 50 (see FIG. 4) that can communicate with the first openings 9 formed in each recess 8a of the second substrate 3. By bonding the front surface of the third substrate 4 and the rear surface of the second substrate with an adhesive 10, a first common flow path (first flow path) 50 that communicates with all the first openings formed in the second substrate 3 is formed as shown in FIG. 4. In addition, a second opening (first flow path opening) 51 is formed at one end of the recess 50a, and a third opening (second flow path opening) 52 is formed at the other end so as to penetrate the third substrate 4 as a flow path opening. The second opening 51 and the third opening 52 are connected to an external liquid supply unit 504, and ink supplied from the liquid supply unit 504 is supplied to the first common flow path 50 through the second opening 51 and the third opening 52.

[0024] Here, the cross-sectional structure and planar shape of the substrate 1 will be described with reference to the cross-sectional view of Fig. 4(a) and the plan view of Fig. 4(b). As shown in Fig. 4(a), the first substrate 2 has a first electrode 16, a piezoelectric film 17, a second electrode 18, a first insulating film 19, a first protective film 20, and a base substrate 15. Furthermore, the first substrate 2 is formed with an ejection port 6 penetrating the substrate 2, and a step 27 communicating with the ejection port 6 by an annular recess surrounding the ejection port 6.

[0025] The base substrate 15 is formed of silicon 13, an insulating film 12 provided on the surface of the silicon 13, and an insulating film 14 provided on the back surface opposite to the surface of the silicon 13. The surface of the insulating film 12 of the base substrate 15, that is, the surface on which the opening edge of the ejection port (the front edge of the ejection port 6 in the ink ejection direction) is formed, forms the surface 5a (first surface) of the first substrate 2. The surface 5a of the first substrate 2 has a flat surface shape. Since the surface 5a of the base substrate 15 is exposed to liquid and the outside air, it is preferable that the insulating films 12 and 14 are films that maintain insulation between the silicon 13 and the outside. However, when a water-based solution is not used or when the base substrate 15 is not exposed to the outside air, the base substrate 15 may be configured not to have the insulating film 12. In addition, since the first electrode 16 is formed on the back surface side of the base substrate 15 (the -Z direction side in FIG. 4(a)), it is preferable to form the insulating film 14 on the base substrate 15. In the present embodiment, the base substrate 15 has a structure in which the silicon 13 is sandwiched between the insulating films 12 and 14 made of SiO2, but the base substrate 15 may be formed of only the insulating films 12 and 14. The base substrate 15 may also be formed using other materials such as SiO2, Al2O3, HfO2, and DLC. The insulating film 14 can also be used as an etching stop layer when forming the first electrode 16, so it is preferable to include it in the base substrate 15. It is preferable to use a base substrate 15 according to the desired characteristics and the desired manufacturing method.

[0026] A first electrode 16, which is a common electrode, is formed on the back surface (lower surface) of the base substrate 15. Pt is used for this first electrode 16. A piezoelectric film 17 made of lead zirconate titanate is formed on the lower side of the first electrode 16. When forming the piezoelectric film 17, sintering is performed at high temperature, so lead may diffuse into surrounding films. In order to prevent lead diffusion, it is preferable to form a ZrO or TiO2 film as a lead diffusion prevention film between the insulating film 14 and the first electrode 16, and when a TiO2 film is formed, a Ti film may be formed as an adhesion improving layer between the insulating film 14 and the first electrode 16. Other materials such as lead titanate, zinc oxide, and aluminum nitride may also be used for the piezoelectric film 17.

[0027] A second electrode 18 made of TiW, which is an individual electrode, is formed on the back side (lower side) of the piezoelectric film 17. The material of the second electrode 18 may be other materials such as Pt, Ru, Ir, etc. After forming a film of TiW to become the second electrode 18, the second electrode 18 and the piezoelectric film 17 can be formed into a desired shape by performing resist coating, patterning by photolithography, and etching. Then, the first electrode 16 can be formed into a desired shape by performing resist coating, patterning by photolithography, and etching. By repeating the same process, the discharge port 6 can be formed. A first insulating film 19 made of SiO2 is formed on the back side (lower side) of the second electrode 18 to insulate the first electrode 16 and the second electrode 18. The first insulating film 19 may be made of other materials such as Al2O3 and SiN, and also functions as a surface protection film for the piezoelectric film 17 and the discharge port 6.

[0028] In addition, a first contact hole 21 and a second contact hole 22 are formed in a part of the first insulating film 19 for connecting an electrical wiring that electrically connects the first electrode 16 and the second electrode 18. An electrical wiring layer made of AlCu is formed on the back surface side (lower surface side) of the first insulating film 19. In the electrical wiring layer, a first electrical wiring 23, a second electrical wiring 24, a first electrode PAD25 (FIG. 4(b)), and a second electrode PAD26 are formed. The first electrical wiring 23 electrically connects the first electrode 16 and the first electrode PAD25 through the first contact hole 21. The second electrical wiring 24 electrically connects the second electrode 18 and the second electrode PAD26 through the second contact hole 22. A Ti film may be formed between the first insulating film 19 and the electrical wiring layer to improve adhesion. The electrical wiring layer may be formed of other materials.

[0029] A first protective film 20 made of a SiN film is formed on the back side (lower side) of the electrical wiring layer. The first protective film 20 may be formed using other materials such as SiO2, Al2O3, HfO2, DLC, etc., as long as the material maintains the insulating and moisture-proof properties of the electrical wiring layer. However, when a water-based solution is not used or when the vibration plate 7 is not exposed to the outside air, the first protective film 20 may not be provided, or the first protective film 20 may be formed only on a part of the vibration plate 7 to make the vibration plate 7 easily deformable. In the first substrate 2 configured as described above, the first electrode 16, the piezoelectric film 17, and the second electrode 18 provided on the lower surface side of the vibration plate 7 are collectively referred to as the driving element. The back surface 5b (second surface) of the first substrate 2 including the driving element has an uneven shape. The back surface 5b of the first substrate 2 forms the inner wall of the pressure chamber 8.

[0030] As described above, the first substrate 2 is formed with a step 27 communicating with the discharge port 6. As shown in FIG. 4(b), the step 27 is formed in an area larger than the diameter of the discharge port 6 so as to surround the discharge port 6 when viewed from the XY plane. In the example shown in FIG. 4(b), the planar shape of the step 27 is rectangular, but is not limited thereto. The planar shape of the step 27 may be circular or polygonal. For example, the step 27 may be formed so that the length in the X direction is about twice the diameter of the discharge port 6 and the length in the Y direction is about four times the diameter of the discharge port 6, and the discharge port 6 is at the center of the planar shape of the step 27.

[0031] The second substrate 3 is formed of a Si substrate. As described above, a recess 8a is formed on the surface side (upper surface side in the figure) of the second substrate 3 to form a pressure chamber 8 between the first substrate 2 and the second substrate 3. A first opening 9 is formed in the recess 8a so as to penetrate the recess 8a of the second substrate 3. The recess 8a and the first opening 9 can be formed by applying a resist and performing patterning and etching using photolithography. The material of the second substrate 3 may be other materials such as ceramics, resin, metal, etc. The surface of the second substrate 3 and the surface (second surface) of the first substrate 2 are bonded with an adhesive 10 to form the pressure chamber 8. Then, the region of the first substrate 2 inside the bonding surface between the first substrate 2 and the second substrate 3 becomes the vibration plate 7 that constitutes a part of the inner wall of the pressure chamber 8 (the upper wall in FIG. 4). In this embodiment, BCB is used as the adhesive 10, but other materials such as epoxy-based or silicon-based polymer-based materials may be used, or direct bonding of Si may be used. When using a water-based solution, it is preferable to use a water-resistant material for the adhesive 10.

[0032] In this embodiment, the second substrate 3 is bonded to a portion of the first substrate 2 that is thin. As described above, the rear surface 5b of the first substrate 2 has an uneven shape due to the driving elements, and the thickness of the portion where the driving elements are formed is greater than the thickness of the other portions. Hereinafter, the region where the driving elements are formed (first region) is referred to as a thick portion, and the region where the driving elements are not formed is referred to as a thin portion. The second substrate 3 is bonded to the thin portion of the first substrate 2. Therefore, in the diaphragm 7, the annular outer peripheral portion 28 (second region) from the joint between the first substrate 2 and the second substrate 3 to the driving elements is a thin portion. The thin portion has a lower rigidity (elastic coefficient) than the thick portion. Therefore, when the outer peripheral portion 28 of the diaphragm 7 is a thin portion as in this embodiment, it is possible to increase the amount of displacement of the diaphragm 7 compared to when the outer peripheral portion of the diaphragm 7 is a thick portion.

[0033] The third substrate 4 is formed of a Si substrate. A recess 50a for forming the first common flow path 50 is formed on the front surface side (upper surface side in FIG. 3 and FIG. 4(a)) of the third substrate 4. A second opening 51 and a third opening 52 (see FIG. 3) are formed inside the recess 50a so as to penetrate the recess 50a of the third substrate 4. The recess 50a, the second opening 51, and the third opening 52 can be formed by carrying out resist coating, photolithographic patterning, and etching, similar to the recess 8a and the first opening 9 of the second substrate 3. In addition, other materials such as ceramics, resin, and metal may be used as the material of the third substrate 4. The first common flow path 50 can be formed by bonding the surface of the second substrate 3 opposite to the surface on which the pressure chamber 8 is formed (lower surface in FIG. 4(a)) and the surface of the third substrate 4 on which the recess 50a is formed (upper surface in FIG. 4(a)) with an adhesive 10.

[0034] Each of the second opening 51 and the third opening 52 formed in the first common flow path 50 is connected to a liquid sending unit 504 (see FIG. 3). In this embodiment, the liquid sending unit 504 functions as a liquid supply unit (liquid supply means) that supplies liquid to the liquid ejection head 100. Therefore, by connecting the first common flow path 50 and the liquid sending unit 504, it is possible to supply liquid from the liquid sending unit 504 to the substrate 1.

[0035] The first electrode PAD25 and the second electrode PAD26 formed on the first substrate 2 are connected to a flexible wiring substrate 101 (see FIG. 2). This allows electrical signals and power required for ejecting liquid sent from the recording device 700 to be supplied to the substrate 1. When using a water-based solution in the second substrate 3 and the third substrate 4, it is preferable to provide a surface protection layer such as SiC, Al2O3, SiN, or SiO2 on the wall surfaces in contact with the solution.

[0036] Here, the supply and ejection of liquid (ink) in the substrate 1 having the above configuration will be described. When liquid is supplied from the liquid supply unit 504 to the second opening 51 and the third opening 52, the liquid is supplied from each of the first openings 9 to each of the pressure chambers 8 via the first common flow path (flow path) 50. Here, a suction operation is performed to fill each ejection port 6 with the liquid supplied to each of the pressure chambers 8. The suction operation is performed using a suction means provided in the recording device 700. The suction means is composed of a cap member that can be in close contact with the surface of the first substrate 2 of the liquid ejection head 100, and a negative pressure generating means connected to the cap member. The cap member is brought into close contact with the surface of the substrate 1, and negative pressure is applied to the space formed by the cap member and the surface of the substrate 1 by the negative pressure generating means connected to the cap member, thereby sucking in the gas and ink in the ejection port 6 and the pressure chamber 8. As a result, the liquid in the pressure chamber 8 is sucked into the ejection port 6 through the step 27, and the ejection port 6 is filled with ink. When the driving of the negative pressure generating means is stopped to stop the suction of the liquid, a meniscus is formed at the ejection port 6 due to the surface tension of the liquid, and the liquid ejection head 100 enters a state in which it is possible to eject the liquid. During this suction operation, if the surface 5a of the substrate 1 is uneven, the cap member will not be in close contact with the surface 5a of the substrate 1, and external air will enter through the unevenness of the surface 5a, making it impossible to adequately suck in the air and liquid within the ejection port 6 and the pressure chamber 8. In the configuration of this embodiment, the surface 5a of the substrate 1 is flat, so that the air and liquid within the ejection port 6 and the pressure chamber 8 can be appropriately sucked in.

[0037] After the above-mentioned suction operation, when a voltage is applied to the second electrode 18 to drive the piezoelectric film 17, the vibration plate 7 deforms so as to bend inwardly into the pressure chamber 8, and the volume of the pressure chamber 8 changes (decreases). The pressure generated by this change in volume causes the liquid supplied to the pressure chamber 8 and the liquid filling the discharge port 6 to be discharged to the outside. Thereafter, the vibration plate 7 that has been bent inwardly into the pressure chamber 8 returns to its original state, and liquid is supplied from the second opening 51 and the third opening 52, allowing a meniscus to be formed at the discharge port 6.

[0038] The driving of the piezoelectric film 17 can be controlled by the direction and magnitude of the applied voltage. For example, by first bending the vibration plate 7 in a direction that expands the volume of the pressure chamber 8, and then bending it in a direction that reduces the volume of the pressure chamber 8, the volume of the pressure chamber 8 can be changed significantly, and the pressure change for ejection can be increased. In this way, by controlling the change in the volume of the pressure chamber 8, the ejection amount and ejection speed of the liquid can be controlled.

[0039] When the liquid is continuously discharged, foreign matter such as minute droplets and dust may adhere to the surface 5a of the substrate 1, preventing normal discharge from the discharge port 6. For this reason, in the recording device 700, in addition to the liquid suction operation using the cap member described above, a wiping operation is performed to wipe away the droplets and dust using a wiper as a wiping means provided in the recording device 700. At this time, if there are irregularities on the surface of the substrate 1, it may not be possible to perform a sufficient wiping operation. However, since the surface 5a of the substrate 1 in this embodiment is formed flat, foreign matter such as droplets and dust can be properly wiped away.

[0040] Furthermore, in the substrate 1 of this embodiment, a step 27 that communicates with the ejection port 6 is formed on the lower surface (second surface) of the first substrate 2. By forming the step 27, the pressure generated when the pressure chamber 8 contracts is more likely to escape in the direction of the step 27, improving the straightness of the ejected liquid.

[0041] Furthermore, the substrate 1 of this embodiment has a configuration in which the thickness of the vibration plate 7 is locally thinned. That is, the outer peripheral portion 28 of the substrate 1 is formed to be thinner than the region in which the driving element located inside is formed. In this way, by forming the outer peripheral portion 28 of the vibration plate 7 from a thin portion, the outer peripheral portion 28 has a lower rigidity than other portions, and the vibration plate 7 is easily displaced by driving the piezoelectric film 17. For this reason, it is possible to ensure a sufficient amount of displacement of the vibration plate 7 by applying a low applied voltage to the piezoelectric film 17, and it is possible to eject an appropriate amount of ink from the ejection port.

[0042] In this embodiment, the liquid is supplied from both the second opening 51 and the third opening 52 by the liquid supply unit 504, but the present invention is not limited to this. It is also possible to use one of the second opening 51 and the third opening 52 as a liquid supply port and the other opening as a liquid recovery port. In this case, a circulation unit having a function as a liquid supply means for supplying liquid to the liquid ejection head 100 and a function as a liquid recovery means for recovering liquid from the liquid ejection head 100 is used as the liquid supply unit 504. The ink supply side of the circulation unit is connected to one opening, and the ink recovery side is connected to the other opening. This allows ink to be supplied to the ejection port 6 while flowing from one opening to the other opening of the first common flow path 50. That is, it is possible to perform an ejection operation by the liquid ejection head 100 while circulating ink between the liquid supply unit 504 and the liquid ejection head 100. By circulating the ink in this manner, it is possible to remove air bubbles and the like that exist within the pressure chambers 8 and the first common flow path 50, making it possible to maintain the ejection performance of the liquid ejection head 100 in a more optimal state.

[0043] Here, an example is shown in which the rigidity of the diaphragm 7 is approximated as the deflection of a flat plate based on the specific configuration of the substrate 1 in this embodiment. A similar approximate calculation is also performed for a first comparative example having a configuration in which a film is formed on the surface of the substrate as in Patent Document 1, and the substrate 1 in this embodiment is compared with the first comparative example.

[0044] Equation 1 is an approximation for finding the position λ of the neutral plane of the substrate, Equation 2 is a calculation formula for the apparent Young's modulus E of the diaphragm, and Equation 3 is an approximation for the deflection amount u of the diaphragm. In each equation, Ei is the Young's modulus of each layer, ti is the thickness of each layer, W is the width of diaphragm 7, hi is the distance in the thickness direction when surface 5a of the substrate is set to 0, h is the thickness of diaphragm 7, and p is the pressure applied to the diaphragm.

[0045]

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[0046]

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[0047]

number

[0048] The film thickness and Young's modulus of the first substrate 2 constituting the substrate 1 are as follows. The insulating film 12 made of SiO2 has a thickness of 1 um and a Young's modulus of 70 GPa. The silicon 13 has a thickness of 2 um and a Young's modulus of 210 GPa. The insulating film 14 made of SiO2 has a thickness of 0.5 um and a Young's modulus of 70 GPa. The first electrode 16 made of Pt has a thickness of 0.13 um and a Young's modulus of 168 GPa. The lead diffusion prevention film made of TiO2 between the insulating film 14 and the first electrode 16 has a thickness of 0.05 um and a Young's modulus of 168 GPa. The adhesion improvement layer made of Ti between the lead diffusion prevention film and the first electrode 16 has a thickness of 0.05 um and a Young's modulus of 116 GPa. The piezoelectric film 17 has a thickness of 2 um and a Young's modulus of 53 GPa. The second electrode 18 made of TiW has a thickness of 0.1 um and a Young's modulus of 345 GPa. The first insulating film 19 made of SiO2 has a thickness of 0.4 um and a Young's modulus of 70 GPa. The first protective film 20 made of SiN has a thickness of 0.2 um and a Young's modulus of 270 GPa. The size of the diaphragm 7 is 90 um in width and 500 um in length.

[0049] On the other hand, FIG. 5 shows the configuration of the substrate 1A in the first comparative example of this embodiment. The substrate 1A in this first comparative example has a configuration in which a protective film 32 made of polyimide is formed so as to cover the unevenness formed on the surface of the substrate, as in Patent Document 1. The substrate 1A in the first comparative example includes a first substrate 2A, a second substrate 3, and a third substrate 4, as in this embodiment. The laminated structure of the first substrate 2A is the same as the first substrate 2 in this embodiment, except that the protective film 32 is provided. However, in the first comparative example, the orientation of the front and back surfaces of the first substrate 2A is opposite to the orientation of the front and back surfaces of the first substrate 2 in the first embodiment. That is, in the first substrate 2A in the first comparative example, the outer surface 15a of the base substrate 15 forms the inner wall of the pressure chamber 8, and the surface having an uneven shape including the driving element is located on the front surface side of the substrate 1A (the upper surface side of FIG. 5). The uneven shape formed on the front surface side of this first substrate 2A is covered with a protective film 32 made of polyimide, and the surface 5a of the first substrate 2A is formed into a flat surface shape. The protective film 32 made of polyimide has a thickness of 4 um and a Young's modulus of 4 GPa.

[0050] Here, the position λ of the neutral plane of each of the substrate 1 and the substrate 1A and the distance between the piezoelectric film 17 are calculated. The position λ of the neutral plane and the position of the piezoelectric film 17 indicate the distance in the Z direction from the outer surface of the base substrate 15 (the upper surface in FIG. 4(a)) when the outer surface is set as the reference position in the Z direction (Z=0). In the substrates 1 and 1A, the distance from the outer surface of the base substrate 15, which is the reference position, to the piezoelectric film 17 is 3.73 um in both cases. The position λ of the neutral plane of each of the substrates 1 and 1A can be obtained by Equation 1. As a result of the calculation by Equation 1, the position λ of the neutral plane of the substrate 1 in this embodiment is -2.98 um. Therefore, the distance in the Z direction between the neutral plane and the piezoelectric film 17 is 0.75 um, and the apparent thickness of the vibration plate 7 of the substrate 1 is 5.96 um (=2.98 um×2). In contrast, the neutral plane of the substrate 1A of the first comparative example is -3.08 um, the distance in the Z direction between the neutral plane and the piezoelectric film is 0.64 um, and the apparent thickness of the diaphragm 7 on the substrate 1A is 6.16 um (= 3.08 um × 2). Thus, the substrate 1 in this embodiment has a thinner apparent thickness of the diaphragm 7, making it more likely to bend. The apparent Young's modulus E, which indicates the rigidity of the diaphragm 7 of each of the substrates 1 and 1A, can be calculated by Equation 2 using the position λ of the neutral plane obtained by Equation 1, the thickness h of the diaphragm 7, etc.

[0051] Next, the amount of deflection u of the diaphragm 7 of each of the substrates 1 and 1A is calculated. The amount of deflection u is calculated by Equation 3 using the thickness h of the diaphragm 7, the apparent Young's modulus E obtained by Equation 2, and the pressure p applied to the diaphragm 7. When the pressure p applied to the diaphragm 7 is 1 MPa, the amount of deflection of the diaphragm 7 in the substrate 1 of this embodiment is 65.7 um in absolute value. In contrast, the amount of deflection of the diaphragm 7A in the substrate 1A of the first comparison is 54.8 um in absolute value. Therefore, the diaphragm 7 in this embodiment is preferable because it is larger than the amount of deflection of the diaphragm 7A in the first comparative example. In order to obtain the same amount of deflection as the substrate 1 of this embodiment with the substrate 1A of the first comparative example, it is necessary to increase the driving voltage or increase the width and length of the diaphragm 7. Increasing the driving voltage is not preferable because it increases the load on the driving circuit. In addition, increasing the width and length of the diaphragm 7 causes a decrease in the resolution of the formed image and an increase in the size of the substrate 1A, which causes a decrease in performance as a recording device, an increase in manufacturing costs, and a decrease in design freedom.

[0052] As described above, in the substrate 1 in this embodiment, the surface 5a is formed flat by the base substrate 15, so that it is possible to properly perform the suction of liquid and the wiping operation without providing a protective film for flattening the surface 5a of the substrate 1. In addition, it is possible to properly displace the diaphragm 7 with a lower driving voltage.

[0053] Next, the effect of forming the outer peripheral portion 28 of the diaphragm 7 thin for the substrate 1 will be described in comparison with comparative examples of this embodiment. Note that Fig. 5 shows the above-mentioned first comparative example, Fig. 6 shows the second comparative example, and Fig. 7 shows the third comparative example.

[0054] As described above, the substrate 1A of the first comparative example shown in FIG. 5 is formed by adding a polyimide protective film 32 based on the configuration of the first substrate 2 of this embodiment to form a flat surface 5a of the substrate 1A, and has a vibration plate 7A having a configuration simulating the configuration of Patent Document 1. The substrate 1B of the second comparative example shown in FIG. 6 includes a base substrate 15 similar to that of this embodiment, and a vibration plate 7B having a piezoelectric film 17, a first electrode 16, and a second electrode 18 similar to that of this embodiment. However, the first substrate 2B of the second comparative example differs from the first substrate 2 of this embodiment in the following points. That is, when forming the first substrate 2B of the second comparative example, the first insulating film 19 is formed after the ejection port 6 is formed, and resist coating, patterning by photolithography, and etching are performed so that a part of the second electrode 18 is exposed. Thereafter, the second electric wiring 24 is formed, and further, a Ni film 33 is formed by electroforming so as to cover the second electrode 18 and the second electric wiring 24. The Ni film has a thickness of 0.2 um and a Young's modulus of 199 GPa. In this manner, the vibration plate 7B of the substrate 1B shown in the second comparative example has a Ni film formed on the lower surface side of the piezoelectric film 17, and has a configuration simulating the substrate shown in Patent Document 2.

[0055] 7 has a configuration in which a driving element having the same layer structure as the driving element of this embodiment is provided over the entire back surface (lower surface in FIG. 7) of a base substrate 15. That is, a diaphragm 7C of a first substrate 2C in the substrate 1C shown in the third comparative example does not have a thin outer peripheral portion 28 as in the substrate 1 of this embodiment.

[0056] A three-dimensional model structure was created for each of these substrates 1, 1A, 1B, and 1C, and a voltage was applied to the first electrode 16 and the second electrode 18 to perform structural analysis using the finite element method. After calculation, the displacement volume (pL / V) of the pressure chamber 8 per unit voltage was calculated, and the value normalized by the configuration of the substrate 1 of this embodiment shown in Fig. 4 is shown in Fig. 8. Since the value of the displacement volume (pL / V) of the pressure chamber 8 per unit voltage is proportional to the ejection amount, a larger displacement volume of the pressure chamber 8 is preferable because the same ejection amount can be obtained at a lower voltage.

[0057] As shown in FIG. 8, when the displacement volume of the pressure chamber 8 in the substrate 1 of the present embodiment shown in FIG. 4 is set to "1", the ratio of the displacement volume of the pressure chamber 8 in the substrate 1A simulating Patent Document 1 shown in FIG. 5 is 0.43. Therefore, in order to obtain the same ejection amount as the substrate 1 using the substrate 1A, it is necessary to apply a driving voltage that is more than twice as large. Also, the ratio of the displacement volume of the pressure chamber 8 in the substrate 1B simulating Patent Document 2 shown in FIG. 6 is 0.03. Furthermore, the ratio of the displacement volume of the pressure chamber 8 in the substrate 1C shown in FIG. 7 in which the outer periphery 28 of the vibration plate 7C is not thinned is 0.09. Therefore, it is understood that it is necessary to apply a higher driving voltage to the substrates 1B and 1C than to the substrate 1A. Thus, according to the first substrate 2 of the present embodiment in which the outer periphery 28 of the vibration plate is formed by a thin portion, it is possible to drive the vibration plate 7 with a lower driving voltage.

[0058] As described above, in the substrate 1 of this embodiment, the surface 5a is formed flat, so that sufficient liquid suction and wiping operations can be performed. Furthermore, since the vibration plate 7 has a configuration that allows it to bend easily, it is possible to obtain an appropriate amount of displacement of the vibration plate 7 with a low voltage.

[0059] Second embodiment Next, a second embodiment of the present disclosure will be described. Fig. 9 is a schematic diagram showing an enlarged view of a part of the substrate 11 constituting the liquid ejection head in this embodiment, and Fig. 10 is a cross-sectional view taken along line XX in Fig. 9. For simplification, Fig. 9 shows a configuration in which five ejection ports 6 are arranged in the Y direction on the substrate 11.

[0060] As shown in Fig. 9, the substrate 11 in this embodiment is composed of a first substrate 2, a second substrate 31, and a third substrate 41, and these substrates 2, 31, and 41 are made of the same materials and by the same method as those shown in the first embodiment. The difference from the first embodiment is the structure of the second substrate 31 and the third substrate 41, and the first substrate 2 is the same as that shown in the first embodiment. In Figs. 9 and 10, the same reference numerals are used for the same or corresponding parts as those in the first embodiment.

[0061] In addition to the pressure chambers 8 and the first openings (first pressure chamber openings) 9, the second substrate 31 is formed with a fourth opening (second pressure chamber opening) 29 penetrating the second substrate 31 in a recess (first recess) 8a for forming the pressure chambers 8. The third substrate 41 is formed with a recess 50a for forming a first common flow path (first flow path) 50, and a second opening (first flow path opening) 51 penetrating the third substrate 41 in the recess 50a. The third substrate 41 is further formed with a recess (third recess) 53a for forming a second common flow path (second flow path) 53, and a fifth opening (second flow path opening) 54 penetrating the third substrate 41 in the recess 53a. The back surface (lower surface in FIGS. 9 and 10) of the second substrate 31 and the surface (upper surface in FIGS. 9 and 10) of the third substrate 41 are joined with an adhesive 10 to form the first common flow path 50 and the second common flow path 53.

[0062] In the substrate 11 of the present embodiment having the above configuration, the second opening 51 and the fifth opening 54 formed in the third substrate 41 are connected to a liquid circulation unit 504 as a liquid sending unit. That is, either the second opening 51 or the fifth opening 54 is connected to a supply port of the liquid circulation unit 504, and the other is connected to a recovery port of the liquid circulation unit 504. In this example, the second opening 51 is connected to a liquid supply port of the liquid circulation unit 504, and the fifth opening 54 is connected to a liquid recovery port of the liquid circulation unit 504. This makes it possible to supply liquid from the liquid circulation unit 504 to the substrate 11 and recover liquid from the substrate 11. When using an aqueous solution in the second substrate 31 and the third substrate 41, it is preferable to provide a surface protection layer such as SiC, Al2O3, SiN, or SiO2 on the wall surface in contact with the solution. Furthermore, the first electrode PAD25 (see Figure 4 (b)) and the second electrode PAD26 formed on the first substrate 2 are connected to a flexible wiring board 101, so that an electrical signal required for ejecting liquid can be applied to the substrate 1.

[0063] Here, the supply and ejection of liquid (ink) in this embodiment will be described. When liquid is supplied from the liquid circulation unit 504 to the second opening 51, the liquid is supplied from each of the first openings 9 to each of the pressure chambers 8 via the first common flow path 50. Then, the liquid (ink) that has flowed into the pressure chambers 8 flows into the second common flow path 53 via the fourth opening 29, and then flows out of the substrate 1 from the fifth opening 54 and is collected in the liquid circulation unit 504. Next, when the above-mentioned cap member is tightly attached to the flat surface of the substrate 11 and negative pressure is applied to the inside of the cap member by the negative pressure generating means, the liquid supplied to the pressure chambers 8 moves to the ejection port 6 via the step 27, and the ejection port 6 is filled with ink. When the suction of the liquid is stopped here, a meniscus is formed at the ejection port 6 due to the surface tension of the liquid. In this state, when a voltage is applied between the first electrode 16 and the second electrode 18 to drive the piezoelectric film 17, a change in the volume of the pressure chamber occurs as in the first embodiment, and liquid is ejected from the nozzle 6, the nozzle 6 is filled with ink, and a meniscus is formed in sequence.

[0064] As described above, in this embodiment, liquid circulates between the liquid circulation unit 504 and the substrate 11, and the liquid in the pressure chamber 8 constantly flows from the first opening 9 to the fourth opening 29. However, a step 27 is formed in the vibration plate 7 of the first substrate 2 that constitutes the inner wall of the pressure chamber 8 in an area surrounding the ejection port 6. For this reason, the liquid flowing in the pressure chamber 8 enters the area where the step 27 is formed, and further enters the vicinity of the meniscus formation position of the ejection port 6, and then flows out into the pressure chamber 8, thus performing so-called internal ejection port circulation.

[0065] On the other hand, in an inkjet recording device that does not circulate ink, the evaporation of the solvent component from the discharge port 6 progresses during standby time when the ink is not discharged, and the pigment, dye, and other components contained in the liquid are likely to adhere to the inner wall and surface of the discharge port 6. Therefore, when discharge is resumed, discharge defects such as distortion and non-discharge of the discharged liquid due to the increase in viscosity of the ink are likely to occur. In contrast, in this embodiment, even during standby time when discharge is not performed, the liquid is circulated between the liquid discharge head 100 and the liquid circulation unit 504, and the liquid flowing in the pressure chamber 8 is caused to flow to the vicinity of the meniscus formation position of the discharge port 6 by the step 27. Therefore, the viscosity of the liquid is unlikely to increase, and it is possible to suppress the occurrence of discharge defects. As described in the first embodiment, in this embodiment as well, the step 27 can improve the straightness of the discharged liquid, making it possible to maintain good discharge performance for a long period of time.

[0066] It is preferable to change the thickness of the ejection port 6 in the ejection direction while adjusting the balance with the size of the ejection port 6 so as to obtain a desired droplet volume. In this embodiment, the step 27 is formed by an annular recess formed in a portion of the first substrate 2 other than the base substrate 15, but when the thickness of the ejection port 6 is to be increased, the ejection port 6 may be formed including a layer of the first substrate 2 other than the base substrate 15. A specific description will be given below with reference to FIG. 11.

[0067] FIG. 11 is a cross-sectional view showing a substrate 11A in a modified example of this embodiment. The discharge port 6 of the substrate 11A shown in FIG. 11 penetrates the base substrate 15, the first electrode 16, the piezoelectric film 17, the second electrode 18, the first insulating film 19, and the first protective film 20. The first protective film 20 is not necessary if the solution is not water-based. A ring-shaped convex portion is formed on the surface of the first protective film 20 on the pressure chamber 8 side (the lower surface in FIG. 11) using a material with a low Young's modulus such as resin, for example, polyimide, and a step 55 communicating with the discharge port 6 is formed by this. This step 55 can improve the linearity of the discharged droplet even when the thickness of the discharge port 6 is increased, and can lead the liquid flowing in the pressure chamber 8 to the discharge port 6, thereby realizing circulation within the discharge port. Furthermore, since the step 55 is provided locally on the vibration plate 7, the change in the displacement of the vibration plate 7 caused by the formation of this step 55 is very small and does not cause any problem.

[0068] As described above, according to this embodiment and its modified examples, as in the first embodiment, it is possible to properly perform the liquid suction operation and the wiping operation, and to obtain a proper displacement of the vibration plate. Furthermore, according to this embodiment and its modified examples, it is possible to properly circulate the liquid inside the nozzle by the steps 27 and 55 while smoothly supplying and recovering the liquid to the pressure chamber 8. Therefore, it is possible to suppress the occurrence of ejection defects due to evaporation of the ink solvent component from the ejection port 6, and it is possible to improve the straightness of the ejected liquid by the steps 27 or 55, and it is possible to maintain good liquid ejection performance for a long period of time.

[0069] [Other embodiments] In the above embodiment, a full-line type recording apparatus and a liquid ejection head applied thereto are described as examples, but the present disclosure is not limited thereto. The present disclosure can also be applied to a serial type recording apparatus that performs recording while moving a liquid ejection head in the main scanning direction and a liquid ejection head used therein.

[0070] The present disclosure includes the following configurations.

[0071] (Configuration 1) a first substrate having a flat first surface on which ejection ports for ejecting liquid are provided and a second surface on the opposite side to the first surface on which driving elements are provided; a second substrate bonded to the second surface of the first substrate and forming a pressure chamber between the second surface of the first substrate and the second substrate, the pressure chamber being configured to receive a liquid; a liquid ejection head configured such that a portion of the first substrate that forms the pressure chamber forms a vibration plate that is displaced by the drive element, and liquid in the pressure chamber is ejected from the ejection port by the displacement of the vibration plate, the second surface of the first substrate has an uneven shape including the driving element, The liquid ejection head is characterized in that the vibration plate has a second region surrounding a first region in which the ejection ports are provided, the second region having a lower rigidity than the first region.

[0072] (Configuration 2) 2. The liquid ejection head according to configuration 1, wherein the second region is formed to have a smaller thickness than the first region.

[0073] (Configuration 3) 3. The liquid ejection head according to configuration 1 or 2, wherein the first substrate is composed of a base substrate that forms the first surface and a drive element provided on the base substrate.

[0074] (Configuration 4) The first region is formed to include the base substrate, 4. The liquid ejection head according to configuration 3, wherein the second region is formed to include the base substrate and the drive element.

[0075] (Configuration 5) A liquid ejection head described in any one of configurations 1 to 4, characterized in that the driving element has a piezoelectric film, a first electrode provided on one surface of the piezoelectric film, a second electrode provided on the other surface of the piezoelectric film opposite the one surface, and an insulating film provided on the second electrode.

[0076] (Configuration 6) a first recess for forming the pressure chamber is formed on one surface of the second substrate; A liquid ejection head described in any one of configurations 1 to 5, characterized in that the pressure chamber is formed by the first recess and the vibration plate by bonding the one surface of the second substrate to the second surface of the first substrate.

[0077] (Configuration 7) 7. The liquid ejection head according to configuration 6, wherein the second substrate has a pressure chamber opening formed therein, the pressure chamber opening penetrating the second substrate and communicating with the pressure chamber.

[0078] (Configuration 8) Further comprising a third substrate bonded to the other surface of the second substrate opposite to the one surface, a flow path communicating with the pressure chamber opening is formed between the third substrate and the second substrate; The liquid ejection head according to configuration 7, wherein the third substrate is formed with a flow path opening that penetrates the third substrate and communicates with the flow path.

[0079] (Configuration 9) the flow path opening includes a first flow path opening and a second flow path opening connected to a liquid supply means; 9. The liquid ejection head according to configuration 8, wherein the liquid supplied to the flow path from the first flow path opening and the second flow path opening is supplied to the pressure chamber and the ejection port from the pressure chamber opening.

[0080] (Configuration 10) the flow path opening includes a first flow path opening connected to a liquid supply means and a second flow path opening connected to a liquid recovery means; the liquid supplied from the first flow path opening to the flow path is supplied to the second flow path opening, and is supplied from the pressure chamber opening to the ejection port via the pressure chamber, 9. The liquid ejection head according to configuration 8, wherein the liquid supplied to the second flow path opening flows out into the liquid recovery means.

[0081] (Configuration 11) the pressure chamber opening includes a first pressure chamber opening and a second pressure chamber opening, the flow path includes a first flow path communicating with the first pressure chamber opening and a second flow path communicating with the second pressure chamber opening, the flow path opening includes a first flow path opening communicating with the first flow path and connected to a liquid supply means, and a second flow path opening communicating with the second flow path and connected to a liquid recovery means, the liquid supplied from the first flow path opening to the first flow path is supplied to the pressure chamber via the first pressure chamber opening, and then is supplied to the second pressure chamber opening, while being supplied to the second pressure chamber opening via the ejection port; 9. The liquid ejection head according to configuration 8, wherein the liquid supplied to the second pressure chamber opening passes through the second flow path and flows out from the second flow path opening to the liquid recovery means.

[0082] (Configuration 12) A second recess for forming a first flow path is formed on one surface of the third substrate, the first flow path is formed by bonding the other surface of the second substrate and the one surface of the third substrate; The liquid ejection head according to configuration 9 or 10, wherein the first flow path opening and the second flow path opening penetrating the third substrate are formed in the second recess.

[0083] (Configuration 13) a second recess for forming the first flow path and a third recess for forming the second flow path are formed on one surface of the third substrate; the first flow path and the second flow path are formed by bonding the other surface of the second substrate and the one surface of the third substrate, the first flow path opening penetrating the third substrate is formed in the second recess, 12. The liquid ejection head according to configuration 11, wherein the third recess has the second flow path opening formed therein, the second flow path opening penetrating the third substrate.

[0084] (Configuration 14) a step is formed on the second surface of the first substrate so as to surround the ejection port and communicate with the ejection port; 14. The liquid ejection head according to any one of configurations 1 to 13, wherein the step is formed in an area smaller than an area in which the drive elements are formed.

[0085] (Configuration 15) 15. A liquid ejection head according to configuration 14, wherein the step is defined by an annular recess formed on the second surface.

[0086] (Configuration 16) 15. A liquid ejection head according to configuration 14, wherein the step is formed by an annular convex portion formed on the second surface.

[0087] (Configuration 17) 17. The liquid ejection head according to any one of configurations 1 to 16, wherein a protective film is formed on a portion that comes into contact with the liquid or the outside air.

[0088] (Configuration 18) A liquid ejection head according to any one of configurations 1 to 17, a conveying means for conveying a recording medium to the liquid ejection head; a liquid supplying means for supplying liquid to the liquid ejection head, a liquid ejection head that ejects the liquid supplied from the liquid supply means onto the recording medium, thereby forming an image on the recording medium;

[0089] (Configuration 19) 19. The recording apparatus according to configuration 18, further comprising a liquid recovery means for recovering the liquid supplied to the liquid ejection head. [Explanation of symbols]

[0090] 1 Board 2 First board 3 Second board 5a surface 5b Back 6 Outlet 7 Vibration plate 8. Pressure Chamber 15 Base board 100 Liquid ejection head 700 Recording Device

Claims

1. a first substrate having a flat first surface on which ejection ports for ejecting liquid are provided and a second surface on which drive elements are provided opposite to the first surface; a second substrate bonded to the second surface of the first substrate and forming a pressure chamber configured to receive a liquid between the second surface of the first substrate and the second substrate; a liquid ejection head configured such that a portion of the first substrate that forms the pressure chamber forms a vibration plate that is displaced by the drive element, and the liquid in the pressure chamber is ejected from the ejection port by the displacement of the vibration plate, the second surface of the first substrate has an uneven shape including the driving element, The liquid ejection head is characterized in that the vibration plate has a second region surrounding a first region in which the ejection ports are provided, and the second region has a lower rigidity than the first region.

2. 2. The liquid ejection head according to claim 1, wherein the second region is formed to have a thickness thinner than that of the first region.

3. 3. The liquid ejection head according to claim 1, wherein the first substrate is composed of a base substrate that forms the first surface, and a driving element provided on the base substrate.

4. the first region is formed to include the base substrate and the driving element, 4. The liquid ejection head according to claim 3, wherein the second region is formed to include the base substrate.

5. The liquid ejection head described in claim 1, characterized in that the driving element has a piezoelectric film, a first electrode provided on one surface of the piezoelectric film, a second electrode provided on the other surface opposite to the one surface of the piezoelectric film, and an insulating film provided on the second electrode.

6. a first recess for forming the pressure chamber is formed on one surface of the second substrate; The liquid ejection head according to claim 1 , wherein the pressure chamber is formed by the first recess and the vibration plate by bonding the one surface of the second substrate to the second surface of the first substrate.

7. 7. The liquid ejection head according to claim 6, wherein a pressure chamber opening that penetrates the second substrate and communicates with the pressure chamber is formed in the second substrate.

8. further comprising a third substrate bonded to the other surface of the second substrate opposite to the one surface, a flow path communicating with the pressure chamber opening is formed between the third substrate and the second substrate; 8. The liquid ejection head according to claim 7, wherein a flow path opening that penetrates the third substrate and communicates with the flow path is formed in the third substrate.

9. the flow path openings include a first flow path opening and a second flow path opening connected to a liquid supply means; 9. The liquid ejection head according to claim 8, wherein the liquid supplied to the flow path from the first flow path opening and the second flow path opening is supplied to the pressure chamber and the ejection port from the pressure chamber opening.

10. the flow path openings include a first flow path opening connected to a liquid supply means and a second flow path opening connected to a liquid recovery means; the liquid supplied from the first flow path opening to the flow path is supplied to the second flow path opening, and is supplied from the pressure chamber opening to the ejection port via the pressure chamber, 9. The liquid ejection head according to claim 8, wherein the liquid supplied to the second flow path opening flows out into the liquid recovery means.

11. the pressure chamber openings include a first pressure chamber opening and a second pressure chamber opening; the flow path includes a first flow path communicating with the first pressure chamber opening and a second flow path communicating with the second pressure chamber opening; the flow path openings include a first flow path opening that communicates with the first flow path and is connected to a liquid supply means, and a second flow path opening that communicates with the second flow path and is connected to a liquid recovery means, the liquid supplied from the first flow path opening to the first flow path is supplied to the pressure chamber via the first pressure chamber opening, and then supplied to the second pressure chamber opening, and is also supplied to the second pressure chamber opening via the ejection port; 9. A liquid ejection head according to claim 8, wherein the liquid supplied to the second pressure chamber opening passes through the second flow path and flows out from the second flow path opening to the liquid recovery means.

12. a second recess for forming a first flow path is formed on one surface of the third substrate; the first flow path is formed by bonding the other surface of the second substrate and the one surface of the third substrate, 11. The liquid ejection head according to claim 9, wherein the first flow path opening and the second flow path opening penetrating the third substrate are formed in the second recess.

13. a second recess for forming the first flow path and a third recess for forming the second flow path are formed on one surface of the third substrate; the first flow path and the second flow path are formed by bonding the other surface of the second substrate and the one surface of the third substrate, the first flow path opening penetrating the third substrate is formed in the second recess; The liquid ejection head according to claim 11, wherein the second flow path opening penetrating the third substrate is formed in the third recess.

14. a step that is in communication with the ejection port and surrounds the ejection port on the second surface of the first substrate; 2. The liquid ejection head according to claim 1, wherein the step is formed in an area smaller than an area in which the driving elements are formed.

15. 15. The liquid ejection head according to claim 14, wherein the step is formed by an annular recess formed on the second surface.

16. 15. The liquid ejection head according to claim 14, wherein the step is formed by an annular convex portion formed on the second surface.

17. 2. The liquid ejection head according to claim 1, wherein a protective film is formed on a portion that comes into contact with the liquid or the outside air.

18. The concave-convex shape is a shape formed by arranging the drive element so as to protrude into the pressure chamber, In the diaphragm, the first region is a region surrounding the ejection port, and the drive element is provided so as to protrude toward the inside of the pressure chamber, 2. The liquid ejection head according to claim 1, wherein the second region surrounds the first region and is a region in which the driving element is not provided.

19. The diaphragm further includes a third region in addition to the first region and the second region, the first region is a region surrounding the ejection port, and in which the drive element is disposed so as to protrude into the pressure chamber, the second region is a region surrounding the first region and provided with wiring for supplying power to the driving element, The third region is a region that surrounds the second region and is bonded to the second substrate.

2. The liquid ejection head according to claim 1.

20. The liquid ejection head according to claim 1; a conveying means for conveying a recording medium relative to the liquid ejection head; a liquid supply means for supplying liquid to the liquid ejection head, a liquid ejection head for ejecting the liquid supplied from the liquid supply means onto the recording medium, thereby forming an image on the recording medium;

21. 21. The recording apparatus according to claim 20, further comprising a liquid recovery unit that recovers the liquid supplied to the liquid ejection head.

22. the liquid supply means and the liquid recovery means are constituted by a circulation means, 22. The recording apparatus according to claim 21, wherein the liquid is circulated between the circulation means and the liquid ejection head.

23. a suction means that is in close contact with a first surface of the first substrate of the liquid ejection head and that sucks liquid from the ejection openings; 23. The recording apparatus according to claim 20, further comprising a wiping device that wipes the first surface of the first substrate of the liquid ejection head.

Images