Liquid dispensing 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 a liquid such as ink and a recording apparatus. [Background Art]

[0002] In recent years, in inkjet recording apparatuses, due to the demands for high-definition images and high-speed recording, liquid ejection heads in which ejection ports are arranged at high density have been required. Among liquid ejection heads using piezoelectric elements that meet such demands, bend-mode liquid ejection heads are widely used because it is relatively easy to arrange piezoelectric elements with high density and high precision. A bend-mode liquid ejection head forms an inner wall of a pressure chamber with a laminated structure consisting of a piezoelectric element and a diaphragm, and deforms the piezoelectric element in an in-plane direction by applying a voltage, thereby deforming (bending) the diaphragm in an out-of-plane direction to generate pressure in the pressure chamber.

[0003] Patent Literature 1 and Patent Literature 2 disclose bend-mode liquid ejection heads. In the liquid ejection head disclosed in Patent Literature 1, a substrate having ejection ports (nozzles) formed therein is arranged so as to close the pressure chamber, and a region of the substrate that is not fixed by the walls of the pressure chamber serves as a diaphragm. An electrode and a piezoelectric element are formed on the surface of the substrate constituting the diaphragm, and liquid is ejected from the ejection ports by the deformation of the piezoelectric element.

[0004] Further, Patent Literature 2 discloses that in a substrate having ejection ports (nozzles) formed therein, a first electrode, a piezoelectric element, and a second electrode are formed on the substrate, and further a nozzle plate formed of a metal material covering the entire substrate on the second electrode is provided. A bend-mode liquid ejection head is formed by joining the surface of the nozzle plate on the metal material side to one side of a base material provided with an opening that serves as a pressure chamber. [Prior Art Documents] [Patent Literatures]

[0005] [Patent Literature 1] Japanese Patent Publication No. 2014-172323 [Patent Document 2] Japanese Patent Publication No. 2012-71587 [Overview of the project] [Problems that the invention aims to solve]

[0006] In the configuration of Patent Document 1, electrodes and piezoelectric elements are formed on the surface opposite to the pressure chamber where the nozzle is formed, resulting in irregularities on the substrate surface. Therefore, a protective film or water-repellent film is formed to fill these irregularities, creating a flat surface shape on the substrate. This makes it possible to bring the cap member into close contact with the substrate surface, enabling a suction operation to draw ink from the surface side of the substrate. It also enables proper wiping operations to remove ink and dust adhering to the substrate surface with a wiper. However, forming a protective film or water-repellent film on the diaphragm surface makes the diaphragm thicker and less prone to displacement. On the other hand, in Patent Document 2, although no irregularities are created on the diaphragm surface, the entire diaphragm is covered with a metal material, making the diaphragm harder and reducing the amount of displacement.

[0007] Thus, in the technologies described in Patent Documents 1 and 2, the diaphragm is configured to be difficult to displace, and in order to obtain a sufficient amount of displacement of the diaphragm, it is necessary to apply a large driving voltage to the piezoelectric element.

[0008] This disclosure aims to provide a liquid head suitable for liquid suction and wiping operations, as well as a recording device using the same, which makes it possible to reduce the drive voltage required to obtain an appropriate displacement amount for the diaphragm. [Means for solving the problem]

[0009] This disclosure relates to a liquid discharge head comprising: a first substrate having a discharge port for discharging liquid on a flat first surface and a drive element on a second surface opposite to the first surface; and a second substrate joined to the second surface of the first substrate and forming a pressure chamber configured to supply liquid between the first substrate and the second surface, wherein the portion of the first substrate forming the pressure chamber forms a diaphragm that is displaced by the drive element, and the liquid in the pressure chamber is discharged from the discharge port as the diaphragm is displaced, before The diaphragm is located at the outlet It has a first region surrounding the drive element and a second region surrounding the first region, the first region including the drive element, the second surface in the first region protrudes further into the pressure chamber than the second surface in the second region, and the rigidity of the second region is greater than the rigidity of the first region. It is characterized by being low. [Effects of the Invention]

[0010] According to this disclosure, it becomes possible to reduce the drive voltage required to obtain an appropriate displacement amount for the diaphragm, and to provide a liquid head suitable for liquid suction and wiping operations, as well as a recording device equipped therewith. [Brief explanation of the drawing]

[0011] [Figure 1] This is a block diagram showing a schematic representation and control configuration of an inkjet recording device. [Figure 2] This is a perspective view showing the overall configuration of the liquid dispensing head in the embodiment. [Figure 3] This is an exploded perspective view showing a magnified portion of the circuit board of the liquid dispensing head. [Figure 4] Figure 3 shows a cross-sectional view along the line IVa-IVa and a plan view of region F shown in Figure 3. [Figure 5] This is a cross-sectional view showing an enlarged portion of the substrate in the first comparative example. [Figure 6] This is a cross-sectional view showing an enlarged portion of the substrate in the second comparative example. [Figure 7] This is a cross-sectional view showing an enlarged portion of the substrate in a modified example of the first embodiment. [Figure 8] Figures 4 to 7 show the displacement volume of the compression chamber per unit voltage for each substrate. [Figure 9]It is an exploded perspective view showing an enlarged part of a substrate according to a second embodiment. [Figure 10] It is a cross-sectional view taken along line X-X in FIG. 9. [Figure 11] It is an enlarged cross-sectional view showing a part of a substrate according to a modification of the second embodiment. DESCRIPTION OF EMBODIMENTS

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The following embodiments do not limit the present invention according to the claims, and not all combinations of features described in the present embodiment are necessarily essential to the solution of the present disclosure. Further, although an inkjet head that forms an image by ejecting ink as a liquid among liquid ejection heads will be described below, the liquid ejection head of the present disclosure is also applicable to those that eject liquids other than ink.

[0013] (First Embodiment) FIG. 1(a) is a schematic configuration diagram of an inkjet recording apparatus 700 (hereinafter, also simply referred to as recording apparatus 700) according to the present embodiment. As shown in FIG. 1(a), a sheet-shaped recording medium 703 is conveyed in the X direction by a conveying means 702, and passes below a recording unit 701 at a predetermined speed. The recording unit 701 is mainly configured of a liquid ejection head 100 described later. In the liquid ejection head 100, a plurality of ejection ports that eject ink, which is a liquid containing a color material, as droplets are arranged in a range corresponding to the width of the recording medium along a direction (Y direction) intersecting (orthogonal in the present embodiment) the conveying direction of the recording medium. When the recording medium 703 passes below the liquid ejection head 100, ejection elements described later provided corresponding to each ejection port of the liquid ejection head 100 are driven according to ejection data, and eject ink in the Z direction from the ejection ports toward the recording medium to record an image. As described above, the recording apparatus 700 according to the present embodiment is a full-line type recording apparatus that performs recording by ejecting ink from ejection port arrays arranged along the width direction (Y direction) of the recording medium 703 while continuously conveying the recording medium 703.

[0014] FIG. 1(b) is a block diagram showing a control configuration of the recording apparatus in the present embodiment and a second embodiment described later. The recording apparatus 700 includes a CPU 500, a ROM 501, and a RAM 502. The CPU 500 comprehensively controls each part of the recording apparatus 700 while using the RAM 502 as a work area according to a program stored in the ROM 501. For example, the CPU 500 performs predetermined image processing on image data received from an externally connected host device 600 in accordance with programs and parameters stored in the ROM 501, and generates ejection data for driving driving elements of the liquid ejection head 100. The CPU 500 drives the liquid ejection head 100 in accordance with the ejection data to eject ink at a predetermined frequency. In addition, the CPU 500 drives a conveyance motor 503 provided in a conveyance means 702 at a speed corresponding to the ejection frequency of the ejection operation by the liquid ejection head 100, and conveys a 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] In addition, the liquid feeding unit 504 is a unit for supplying liquid (ink) to the liquid ejection head 100. Under the management of the CPU 500, the liquid feeding unit 504 controls an internally provided pressure control unit, a switching mechanism, and the like, and controls the flow of ink in an ink flow path including the liquid ejection head 100. The liquid feeding 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 feeding unit 504 has a function as a liquid circulation unit (circulation means), the liquid feeding unit 504 performs supply of ink to the liquid ejection head 100 and collection of ink from the liquid ejection head 100.

[0016] Furthermore, the recovery unit 505 is a unit that performs processing to maintain and restore the liquid (ink) ejection performance of the liquid ejection head 100, and is controlled by the CPU 500. The recovery unit 505 includes a suction means for forcibly sucking liquid from the ejection port of the liquid ejection head 100, and a wiping means for performing a wiping operation to remove foreign matter such as minute liquid droplets and dust adhering to the surface of the liquid ejection head 100. The suction means includes a cap member provided so as to be able to be closely attached to and separated from the surface of the liquid ejection head, and a negative pressure generating means connected to the cap member. By driving the negative pressure generating means with the cap member in close contact with the surface of the ejection head 100, a suction operation can be performed to forcibly suck gas and liquid from the ejection port inside the liquid ejection head 100. This suction operation is performed in filling operations to fill the pressure chamber and ejection port of the liquid ejection head 100 with liquid, and in suction recovery operations to discharge viscous liquid (ink) etc. that has formed in the ejection port and replace it with liquid (ink) suitable for ejection. Furthermore, the wiping means consists of a wiper that moves while in contact with the surface of the liquid discharge head 100, and a wiper driving means that moves the wiper. By moving the wiper while it is in contact with the surface of the liquid discharge head 100 using the wiper driving means, it becomes possible to wipe away foreign matter adhering to the surface of the liquid discharge head 100.

[0017] Figure 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 electrical wiring board 102 electrically connected to the substrate 1 via a flexible wiring board 101, a power supply terminal 103 for controlling the ejection of ink (liquid), and an input terminal 104 into which control signals and the like are input. As for the method of supplying ink to the liquid ejection head 100, for example, there is a method of supplying ink from an ink tank provided upstream of the liquid ejection head 100 to the pressure chamber inside the liquid ejection head 100 using capillary action or a pump. There is also a method of supplying ink to the pressure chamber of the liquid ejection head 100 by providing ink tanks in both the upstream and downstream flow paths of the liquid ejection head 100 and flowing ink from one ink tank to the other.

[0018] The liquid ejection head 100 has multiple substrates 1 arranged along the Y direction. Multiple ejection ports are densely arranged on each substrate 1, and these ejection ports are configured to provide 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 multiple substrates 1 are arranged along the Y direction to accommodate recording media such as A4 size. By arranging multiple substrates 1, the liquid ejection head 100 forms a row of ejection ports along the Y direction that is longer than the width of an A4 size recording media.

[0019] Here, the configuration of the substrate 1 constituting the liquid discharge head 100 in this embodiment will be explained based on Figures 3 and 4. Figure 3 is an exploded perspective view showing an enlarged portion of the substrate 1 constituting the liquid discharge head 100. Figure 4(a) is a cross-sectional view of the substrate 1 shown in Figure 3 along the line IVa-IVa, and Figure 4(b) is a plan view of the region F enclosed by the dashed line in the substrate of Figure 3(a) as seen from the surface 5a (first surface) of the first substrate 2. Note that in Figure 4(b), for illustrative purposes, the planar shape of the substrate 1 shown in Figure 4(a) excluding the base substrate 15 is shown.

[0020] Figure 3 shows a simplified configuration where five ejection ports 6 are arranged along the Y direction on the substrate 1. However, in reality, 120 ejection ports 6 are arranged in the Y direction at 150 dpi (169.3 μm) intervals, and eight rows of these ejection ports are arranged in the X direction at 1000 μm intervals. By shifting each of the eight rows of ejection ports by 1200 dpi (21.2 μm) in the Y direction, the ejection ports 6 can be arranged at a high density in the Y direction. Note that 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 comprises a first substrate 2, a second substrate 3, and a third substrate 4. These three substrates 2, 3, and 4 are joined together with adhesive 10 in a sequentially stacked state, as shown in Figure 4. In Figures 3 and 4, the upper surface of each substrate 2, 3, and 4 is also referred to as the front surface, and the lower surface as the back surface.

[0022] As shown in Figure 3, the first substrate 2 has discharge ports 6 formed so as to penetrate the substrate 2. The second substrate 3 has recesses (first recesses) 8a formed at positions corresponding to each discharge port 6 to form pressure chambers 8 (see Figure 4), and a first opening (pressure chamber opening) 9 is formed in the recesses 8a so as to penetrate the second substrate 3. By joining the surface of the second substrate 3 and the back surface of the first substrate 2 with adhesive 10, a space is formed between the first substrate 2 and the second substrate 3, as shown in Figure 4(a), and this space becomes the pressure chamber 8. In the example shown in Figures 3 and 4, since five discharge ports 6 are formed in the first substrate 2, five pressure chambers 8 are formed corresponding to each discharge port 6, and each pressure chamber 8 is in communication with each discharge port 6. Furthermore, the part where the first substrate 2 and the second substrate 3 are joined becomes a partition wall of the pressure chamber 8, and the inner region enclosed by this partition wall, that is, the region that constitutes the upper inner wall of the pressure chamber 8, constitutes a displaceable diaphragm 7.

[0023] The third substrate 4 has a recess (second recess) 50a formed therein for forming a first common channel 50 (see Figure 4) that can communicate with the first openings 9 formed in each recess 8a of the second substrate 3. By joining the surface of the third substrate 4 and the back surface of the second substrate with adhesive 10, a first common channel (first channel) 50 that communicates with all the first openings formed in the second substrate 3 is formed, as shown in Figure 4. In addition, a second opening (first channel opening) 51 is formed at one end of the recess 50a, and a third opening (second channel opening) 52 is formed at the other end, both of which penetrate the third substrate 4 as channel openings. 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 channel 50 via 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 in Figure 4(a) and the plan view in Figure 4(b). As shown in Figure 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 has an outlet 6 that penetrates the substrate 2 and a step 27 that communicates with the outlet 6, formed by an annular recess surrounding the outlet 6.

[0025] The base substrate 15 is formed from 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 discharge port (the front edge of the discharge port 6 in the ink discharge 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 be films that maintain insulation between the silicon 13 and the outside. However, if an aqueous solution is not used or if it is not exposed to the outside air, the base substrate 15 may be configured without the insulating film 12. Also, since the first electrode 16 is formed on the back side of the base substrate 15 (the -Z direction side in Figure 4(a)), it is preferable to form the insulating film 14 on the base substrate 15. In this embodiment, the base substrate 15 has a structure in which silicon 13 is sandwiched between SiO2 insulating films 12 and 14, but the base substrate 15 may also be constructed using only the insulating films 12 and 14. Furthermore, the base substrate 15 may be formed using other materials such as SiO2, Al2O3, HfO2, or 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 that suits the desired characteristics and manufacturing method.

[0026] A common electrode, the first electrode 16, is formed on the back side (bottom side) 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 underside of the first electrode 16. When forming the piezoelectric film 17, sintering is performed at a high temperature, which can cause lead to diffuse into the surrounding film. 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. When forming a TiO2 film, a Ti film may be formed between it and the first electrode 16 as an adhesion-improving layer. 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 and acting as an individual electrode, is formed on the back side (bottom side) of the piezoelectric film 17. The material of the second electrode 18 may be other materials such as Pt, Ru, or Ir. After forming the TiW that will become the second electrode 18, the second electrode 18 and the piezoelectric film 17 can be formed into the desired shape by applying a resist and performing patterning and etching using a photolithograph. Subsequently, the first electrode 16 can be formed into the desired shape by applying a resist and performing patterning and etching using a photolithograph. By repeating the same process, the discharge port 6 can be formed. On the back side (bottom side) of the second electrode 18, a first insulating film 19 made of SiO2 is formed 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 or SiN, and also functions as a surface protective film for the piezoelectric film 17 and the discharge port 6.

[0028] Furthermore, a first contact hole 21 and a second contact hole 22 are formed in a part of the first insulating film 19 for connecting 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 side (bottom side) of the first insulating film 19. The electrical wiring layer has a first electrical wiring 23, a second electrical wiring 24, a first electrode PAD 25 (Figure 4(b)), and a second electrode PAD 26 formed thereon. The first electrical wiring 23 electrically connects the first electrode 16 and the first electrode PAD 25 via the first contact hole 21. The second electrical wiring 24 electrically connects the second electrode 18 and the second electrode PAD 26 via 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. Alternatively, the electrical wiring layer may be formed from other materials.

[0029] A first protective film 20 made of a SiN film is formed on the back side (bottom 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 they maintain the insulating and moisture-resistant properties of the electrical wiring layer. However, if an aqueous solution is not used or if the surface is not exposed to the outside air, the first protective film 20 may not be present, or the first protective film 20 may be formed only on a part of the diaphragm 7 to make the diaphragm 7 more easily deformable. In the first substrate 2 configured as described above, the first electrode 16, piezoelectric film 17, and second electrode 18 provided on the bottom side of the diaphragm 7 are collectively referred to as the driving element. The back surface 5b (second surface) of the first substrate 2, including this driving element, has an uneven shape. This 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 has a step 27 that communicates with the discharge port 6. As shown in Figure 4(b), this step 27 is formed in a region 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 Figure 4(b), the planar shape of the step 27 is rectangular, but it is not limited to this. The planar shape of the step 27 can be circular or polygonal. For example, the length in the X direction may be twice the diameter of the discharge port 6, and the length in the Y direction may be about four times the diameter of the discharge port 6, so that the discharge port 6 is at the center of the planar shape of the step 27.

[0031] The second substrate 3 is formed from a Si substrate. On the surface side (top side in the figure) of this second substrate 3, as described above, a recess 8a is formed to form a pressure chamber 8 between it and the first substrate 2. Within this recess 8a, a first opening 9 is formed so as to penetrate the recess 8a of the second substrate 3. The recess 8a and the first opening 9 can be formed by resist coating and patterning and etching by photolithography. The material of the second substrate 3 may be other materials such as ceramics, resin, or metal. Back side A pressure chamber 8 is formed by joining the surface (second surface) of the first substrate 2 with adhesive 10. The region of the first substrate 2 inside the joining surface of the first substrate 2 and the second substrate 3 becomes the diaphragm 7 which constitutes part of the inner wall (upper wall in Figure 4) of the pressure chamber 8. In this embodiment, BCB is used as the adhesive 10, but other materials such as epoxy or silicon polymer materials may be used, or direct bonding of Si may be used. When using an aqueous 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 thinner portion of the first substrate 2. As described above, the back 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) will be referred to as the thick portion, and the region where the driving elements are not formed will be referred to as the thin portion. The second substrate 3 is bonded to this 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 the thin portion. The thin portion has lower rigidity (elastic modulus) compared to the thick portion. For this reason, when the outer peripheral portion 28 of the diaphragm 7 is made into a thin portion, as in this embodiment, it becomes possible to increase the displacement of the diaphragm 7 compared to when the outer peripheral portion of the diaphragm 7 is made into a thick portion.

[0033] The third substrate 4 is formed from a Si substrate. A recess 50a for forming the first common channel 50 is formed on the surface side of the third substrate 4 (the top surface in Figures 3 and 4(a)). Inside this recess 50a, a second opening 51 and a third opening 52 (see Figure 3) are formed 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 resist coating, photolithography, and etching, similar to the recess 8a and the first opening 9 of the second substrate 3. The material of the third substrate 4 may also be other materials such as ceramics, resin, or metal. The first common channel 50 can be formed by joining the surface of the second substrate 3 opposite to the surface where the pressure chamber 8 is formed (the bottom surface in Figure 4(a)) and the surface of the third substrate 4 where the recess 50a is formed (the top surface in Figure 4(a)) with adhesive 10.

[0034] The second opening 51 and the third opening 52, each formed in the first common channel 50, are connected to a liquid supply unit 504 (see Figure 3). In this embodiment, the liquid supply unit 504 functions as a liquid supply unit (liquid supply means) that supplies liquid to the liquid discharge head 100. Therefore, by connecting the first common channel 50 and the liquid supply unit 504, liquid can be supplied from the liquid supply unit 504 to the substrate 1.

[0035] Furthermore, the first electrode PAD25 and the second electrode PAD26 formed on the first substrate 2 are connected to the flexible wiring board 101 (see Figure 2). This allows the electrical signals and power necessary for liquid discharge, sent from the recording device 700, to be supplied to the substrate 1. In addition, when using an aqueous solution on the second substrate 3 and the third substrate 4, it is preferable to provide a surface protective layer such as SiC, Al2O3, SiN, or SiO2 on the wall surface that comes into contact with the solution.

[0036] Here, the supply and discharge 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 first opening 9 to each pressure chamber 8 via the first common flow path (flow path) 50. Here, a suction operation is performed to fill each discharge port 6 with the liquid supplied to each pressure chamber 8. The suction operation is performed using a suction means provided in the recording device 700. The suction means consists of a cap member that can be closely attached to the surface of the first substrate 2 of the liquid discharge head 100, and a negative pressure generating means connected to the cap member. By bringing the cap member into close contact with the surface of the substrate 1 and applying negative pressure in the space formed between the cap member and the surface of the substrate 1 by the negative pressure generating means connected to the cap member, gas and ink in the discharge port 6 and pressure chamber 8 are sucked out. As a result, the liquid in the pressure chamber 8 is sucked through the step 27 to the discharge port 6, and ink is filled into the discharge port 6. Here, when the drive of the negative pressure generating means is stopped and the suction of the liquid is stopped, a meniscus is formed at the discharge port 6 due to the surface tension of the liquid, and the liquid discharge head 100 becomes capable of discharging the liquid. In this suction operation, if there are irregularities on the surface 5a of the substrate 1, the cap member will not be in close contact with the surface 5a of the substrate 1, and outside air will enter through the irregularities on the surface 5a, making it impossible to adequately suction the air and liquid in the discharge port 6 and pressure chamber 8. In the configuration of this embodiment, since the surface 5a of the substrate 1 is flat, the air and liquid in the discharge port 6 and pressure chamber 8 can be properly suctioned.

[0037] After the suction operation described above, when a voltage is applied to the second electrode 18 to drive the piezoelectric film 17, the diaphragm 7 deforms so as to bend inward into the pressure chamber 8, and the volume of the pressure chamber 8 changes (decreases). The pressure generated by this volume change causes the liquid supplied into the pressure chamber 8 and the liquid filled in the discharge port 6 to be discharged to the outside. After this, as the diaphragm 7, which has bent inward into the pressure chamber 8, returns to its original state, liquid is supplied from the second opening 51 and the third opening 52, and a meniscus can 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 diaphragm 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 discharge can be increased. In this way, the amount of liquid discharged and the discharge speed can be controlled by controlling the change in the volume of the pressure chamber 8.

[0039] If liquid is continuously discharged, foreign matter such as tiny droplets and dust may adhere to the surface 5a of the substrate 1, making it impossible to discharge the liquid normally from the discharge port 6. For this reason, in addition to the liquid suction operation using the cap member described above, the recording device 700 performs a wiping operation to remove droplets and dust using a wiper provided as a wiping means in the recording device 700. In this case, 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 this embodiment, the substrate 1 has a step 27 formed on the lower surface (second surface) of the first substrate 2 that communicates with the discharge port 6. Because the step 27 is formed, the pressure generated when the pressure chamber 8 contracts can easily escape in the direction of the step 27, thereby improving the straightness of the discharged liquid.

[0041] Furthermore, the substrate 1 of this embodiment has a configuration in which the thickness of the diaphragm 7 is locally thinned. That is, the outer peripheral portion 28 of the substrate 1 is formed to be thinner than the region where the drive element located inside it is formed. In this way, by forming the outer peripheral portion 28 of the diaphragm 7 with a thin portion, the outer peripheral portion 28 has lower rigidity compared to other parts, making it easier for the diaphragm 7 to be displaced by the driving of the piezoelectric film 17. Therefore, by applying a low voltage to the piezoelectric film 17, it becomes possible to ensure a sufficient amount of displacement of the diaphragm 7, and it becomes possible to discharge the appropriate amount of ink from the discharge port.

[0042] In this embodiment, the case in which liquid is supplied from both the second opening 51 and the third opening 52 by the liquid supply unit 504 has been described, but the embodiment is not limited to this. It is also possible to use one of the second opening 51 and the third opening 52 as the liquid supply port and the other opening as the liquid recovery port. In this case, the liquid supply unit 504 is a circulation unit that has the function of a liquid supply means for supplying liquid to the liquid discharge head 100 and a liquid recovery means for recovering liquid from the liquid discharge head 100. 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 makes it possible to supply ink to the discharge port 6 while the ink flows from one opening to the other in the first common flow path 50. In other words, it becomes possible to circulate ink between the liquid supply unit 504 and the liquid discharge head 100 while the discharge operation by the liquid discharge head 100 is performed. By circulating the ink in this manner, it becomes possible to remove air bubbles and other contaminants present in the pressure chamber 8 and the first common flow path 50, thereby maintaining the liquid discharge performance of the liquid discharge head 100 in a more optimal state.

[0043] Here, we show an example of an approximate calculation of the rigidity of the diaphragm 7 as the deflection of a flat plate, based on the specific configuration of the substrate 1 in this embodiment. We also perform a similar approximate calculation for the first comparative example, which has a configuration in which a film is formed on the surface of the substrate, as in Patent Document 1, and compare the substrate 1 in this embodiment with the first comparative example.

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

[0045]

number

[0046]

number

[0047]

number

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

[0049] On the other hand, Figure 5 shows the configuration of substrate 1A in the first comparative example of this embodiment. Substrate 1A in this first comparative example has a configuration in which a protective film 32 made of polyimide is formed to cover the irregularities formed on the surface of the substrate, similar to Patent Document 1. Substrate 1A in the first comparative example comprises a first substrate 2A, a second substrate 3, and a third substrate 4, similar to this embodiment. The laminated structure of the first substrate 2A is the same as that of 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 reversed compared 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 of the first comparative example, the outer surface 15a of the base substrate 15 constitutes the inner wall of the pressure chamber 8, and the surface having an irregular shape including the drive element is located on the surface side of substrate 1A (the upper surface side in Figure 5). The irregular shape formed on the surface side of the first substrate 2A is covered by the protective film 32 made of polyimide, forming the surface 5a of the first substrate 2A into a flat surface shape. The protective film 32 formed of polyimide has a thickness of 4 μm and a Young's modulus of 4 GPa.

[0050] Here, we calculate the position λ of the neutral plane of substrate 1 and substrate 1A, and the distance to the piezoelectric film 17. Note that the position λ of the neutral plane and the position of the piezoelectric film 17 represent the distance in the Z direction from the outer surface (top surface in Figure 4(a)) of the base substrate 15, with the outer surface being the reference position in the Z direction (Z=0). In 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 μm in both cases. Furthermore, the position λ of the neutral plane of each substrate 1 and substrate 1A can be determined by Equation 1. As a result of the calculation using Equation 1, the position λ of the neutral plane in substrate 1 in this embodiment is -2.98 μm. Therefore, the distance in the Z direction between the neutral plane and the piezoelectric film 17 is 0.75 μm, and the apparent thickness of the diaphragm 7 on substrate 1 is 5.96 μm (= 2.98 μm × 2). In contrast, the neutral plane of substrate 1A in the first comparative example is -3.08 μm, the distance in the Z direction between the neutral plane and the piezoelectric film is 0.64 μm, and the apparent thickness of the diaphragm 7 on substrate 1A is 6.16 μm (= 3.08 μm × 2). Thus, the apparent thickness of the diaphragm 7 in substrate 1 of this embodiment is thinner and it is more flexible. The apparent Young's modulus E, which indicates the rigidity of the diaphragm 7 of each substrate 1 and 1A, can be calculated using Equation 2, using the neutral plane position λ and the thickness h of the diaphragm 7 obtained by Equation 1.

[0051] Next, the amount of deflection u of the diaphragm 7 of substrates 1 and 1A is calculated. This amount of deflection u is calculated using Equation 3, with respect to 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 substrate 1 of this embodiment is 65.7 μm in absolute value. In contrast, the amount of deflection of the diaphragm 7A in substrate 1A of the first comparison is 54.8 μm in absolute value. Therefore, the diaphragm 7 in this embodiment is preferable because its deflection is greater than that of the diaphragm 7A in the first comparative example. In order to obtain the same amount of deflection as substrate 1 of this embodiment using substrate 1A of the first comparative example, it would be necessary to increase the drive voltage or increase the width and length of the diaphragm 7. Increasing the drive voltage is undesirable because it increases the load on the drive circuit. Increasing the width and length of the diaphragm 7 would result in a decrease in the resolution of the formed image and an increase in the size of substrate 1A, leading to a decrease in the performance of the recording device, an increase in manufacturing costs, and a decrease in design flexibility.

[0052] As described above, in this embodiment, since the surface 5a of the substrate 1 is formed flat by the base substrate 15, it becomes possible to properly perform liquid suction and wiping operations without providing a protective film to flatten the surface 5a of the substrate 1. Furthermore, it becomes possible to properly displace the diaphragm 7 with a lower drive voltage.

[0053] Next, the effects of forming the outer peripheral portion 28 of the diaphragm 7 thinly on the substrate 1 will be explained in comparison with the comparative examples of this embodiment. Figure 5 shows the first comparative example, Figure 6 shows the second comparative example, and Figure 7 shows the third comparative example.

[0054] As described above, the substrate 1A of the first comparative example shown in Figure 5 is formed by adding a polyimide protective film 32 to the configuration of the first substrate 2 of this embodiment to create a flat surface 5a of the substrate 1A, and has a diaphragm 7A with a configuration that mimics the configuration of Patent Document 1. The substrate 1B of the second comparative example shown in Figure 6 comprises a base substrate 15 similar to that of this embodiment, and a diaphragm 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 respects. That is, when forming the first substrate 2B of the second comparative example, after forming the discharge port 6, a first insulating film 19 is deposited, and resist coating, photolithography, and etching are performed so that a part of the second electrode 18 is exposed. After that, the second electrical wiring 24 is formed, and furthermore, a Ni film 33 is formed by electroforming to cover the second electrode 18 and the second electrical wiring 24. The thickness of the Ni film is 0.2 μm, and the Young's modulus is 199 GPa. Thus, the diaphragm 7B of the substrate 1B shown in the second comparative example has a Ni film formed on the lower side of the piezoelectric film 17, and has a configuration that mimics the substrate shown in Patent Document 2.

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

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

[0057] As shown in Figure 8, when the displacement volume of the pressure chamber 8 in the substrate 1 of this embodiment shown in Figure 4 is set to "1", the ratio of the displacement volume of the pressure chamber 8 in the substrate 1A, which simulates Patent Document 1 shown in Figure 5, is 0.43. Therefore, it can be seen that in order to obtain the same discharge volume as substrate 1 with substrate 1A, it is necessary to apply more than twice the driving voltage. Furthermore, the ratio of the displacement volume of the pressure chamber 8 in the substrate 1B, which simulates Patent Document 2 shown in Figure 6, is 0.03. Moreover, the ratio of the displacement volume of the pressure chamber 8 in the substrate 1C shown in Figure 7, where the outer peripheral portion 28 of the diaphragm 7C is not thinned, is 0.09. Therefore, it can be seen that in substrates 1B and 1C, it is also necessary to apply a higher driving voltage than in substrate 1A. Thus, according to the first substrate 2 of this embodiment, in which the outer peripheral portion 28 of the diaphragm is formed by a thinned portion, it becomes possible to drive the diaphragm 7 with a lower driving voltage.

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

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

[0060] As shown in Figure 9, the substrate 11 in this embodiment is composed of a first substrate 2, a second substrate 31, and a third substrate 41. These substrates 2, 31, and 41 are made of the same materials and methods as those shown in the first embodiment described above. The differences from the first embodiment are in the structure of the second substrate 31 and the third substrate 41, while the first substrate 2 is the same as that shown in the first embodiment. In Figures 9 and 10, the same or equivalent parts as in the first embodiment are denoted by the same reference numerals.

[0061] The second substrate 31 has a pressure chamber 8 and a first opening (first pressure chamber opening) 9, as well as a fourth opening (second pressure chamber opening) 29 formed in a recess (first recess) 8a for forming the pressure chamber 8, which penetrates the second substrate 31. The third substrate 41 has a recess 50a for forming a first common channel (first channel) 50, and a second opening (first channel opening) 51 that penetrates the third substrate 41 within this recess 50a. Furthermore, the third substrate 41 has a recess (third recess) 53a for forming a second common channel (second channel) 53, and a fifth opening (second channel opening) 54 that penetrates the third substrate 41 within the recess 53a. The first common channel 50 and the second common channel 53 are formed by joining the back surface of the second substrate 31 (bottom surface in Figures 9 and 10) and the front surface of the third substrate 41 (top surface in Figures 9 and 10) with adhesive 10.

[0062] In the substrate 11 of this embodiment having the above configuration, the second opening 51 and the fifth opening 54 formed on the third substrate 41 are connected to a liquid circulation unit 504 which serves as a liquid supply unit. That is, one of the second opening 51 and the fifth opening 54 is connected to the supply port of the liquid circulation unit 504, and the other is connected to the recovery port of the liquid circulation unit 504. In this example, the second opening 51 is connected to the liquid supply port of the liquid circulation unit 504, and the fifth opening 54 is connected to the 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 to recover liquid from the substrate 11. When using an aqueous solution on the second substrate 31 and the third substrate 41, it is preferable to provide a surface protective layer such as SiC, Al2O3, SiN, or SiO2 on the wall surface that comes into 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 the flexible wiring board 101, thereby enabling the application of electrical signals necessary for liquid discharge to the substrate 1.

[0063] Here, the supply and discharge 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 to each pressure chamber 8 from each first opening 9 via the first common flow path 50. The liquid (ink) that has flowed into the pressure chamber 8 then flows into the second common flow path 53 via the fourth opening 29, and then flows out to the outside of the substrate 1 from the fifth opening 54 and is collected by the liquid circulation unit 504. Next, the aforementioned cap member is brought into close contact with 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 chamber 8 moves to the discharge port 6 via the step 27, and ink is filled into the discharge port 6. When the suction of the liquid is stopped at this point, a meniscus is formed at the discharge 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, similar to the first embodiment, and liquid is discharged from the discharge port 6, ink is filled into the discharge port 6, 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 is constantly flowing from the first opening 9 to the fourth opening 29. However, a step 27 is formed in the area surrounding the discharge port 6 on the diaphragm 7 of the first substrate 2 which constitutes the inner wall of the pressure chamber 8. Therefore, the liquid flowing in the pressure chamber 8 enters the area where the step 27 is formed, and after penetrating further to the vicinity of the meniscus formation position of the discharge port 6, it flows out into the pressure chamber 8, resulting in so-called internal circulation of the discharge port.

[0065] On the other hand, in inkjet recording devices that do not circulate ink, during the standby time when ink is not being ejected, the solvent components evaporate from the ejection port 6, and the pigments, dyes, and other components contained in the liquid tend to adhere to the inner wall and surface of the ejection port 6. As a result, when ejection is resumed, ejection defects such as unevenness or failure to eject the ejected liquid are likely to occur due to the increased viscosity of the ink. In contrast, in this embodiment, even during the standby time when ejection is not being performed, the liquid is circulated between the liquid ejection head 100 and the liquid circulation unit 504, and the liquid flowing in the pressure chamber 8 is guided by the step 27 to the vicinity of the meniscus formation position of the ejection port 6. As a result, the viscosity of the liquid is less likely to increase, and the occurrence of ejection defects can be suppressed. Furthermore, as described in the first embodiment, in this embodiment as well, the step 27 can improve the straightness of the ejected liquid, making it possible to maintain good ejection performance over a long period of time.

[0066] Furthermore, it is preferable to adjust the thickness of the discharge port 6 in the discharge direction while balancing it with the size of the discharge port 6 to achieve the desired droplet volume. In this embodiment, a step 27 is formed by an annular recess formed in the part of the first substrate 2 other than the base substrate 15, but if the thickness of the discharge port 6 is to be increased, the discharge port 6 may be formed including the layers of the first substrate 2 other than the base substrate 15. The following will be explained in detail with reference to Figure 11.

[0067] Figure 11 is a cross-sectional view showing a modified substrate 11A of this embodiment. The discharge port 6 of the substrate 11A shown in Figure 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 aqueous. An annular protrusion is formed on the pressure chamber 8 side surface of the first protective film 20 (the bottom surface in Figure 11) using a low Young's modulus material such as resin, for example, polyimide, thereby forming a step 55 that communicates with the discharge port 6. This step 55 improves the straightness of the discharged droplets even when the thickness of the discharge port 6 is increased, and also guides the liquid flowing in the pressure chamber 8 to the discharge port 6, enabling circulation within the discharge port. Furthermore, since the step 55 is provided locally on the diaphragm 7, the change in displacement of the diaphragm 7 due to the formation of this step 55 is very small and does not pose a problem.

[0068] As described above, according to this embodiment and its modifications, it is possible to perform liquid suction and wiping operations appropriately, as in the first embodiment, and to obtain an appropriate amount of displacement of the diaphragm. Furthermore, according to this embodiment and its modifications, it is possible to smoothly supply and collect liquid to the pressure chamber 8, while properly circulating the liquid inside the nozzle by the steps 27 and 55. As a result, it is possible to suppress the occurrence of discharge failures due to evaporation of the solvent component of the ink from the discharge port 6, and to improve the straightness of the discharged liquid by the steps 27 or 55, thereby maintaining good liquid discharge performance over a long period of time.

[0069] [Other embodiments] In the embodiments described above, a full-line recording device and a liquid ejection head applied thereto were used as examples, but the disclosure is not limited thereto. The disclosure is also applicable to a serial recording device and a liquid ejection head used therein, which perform recording while moving the liquid ejection head in the main scanning direction.

[0070] Furthermore, this disclosure includes the following components.

[0071] (Composition 1) A first substrate having a discharge port for discharging liquid on a flat first surface, and a drive element on a second surface opposite to the first surface, The first substrate is bonded to the second surface of the first substrate, and a second substrate is formed between the first substrate and the second surface of the first substrate, forming a pressure chamber configured to supply liquid. The liquid discharge head is configured such that the portion of the first substrate forming the pressure chamber has a diaphragm that is displaced by the drive element, and the liquid in the pressure chamber is discharged from the discharge port as the diaphragm is displaced, The second surface of the first substrate has an uneven shape including the drive element, The diaphragm is characterized in that the rigidity of the second region surrounding the first region is lower than the rigidity of the first region in which the discharge port is provided.

[0072] (Configuration 2) The liquid dispensing head according to configuration 1, characterized in that the second region is formed with a thinner film thickness than the first region.

[0073] (Composition 3) The liquid discharge head according to configuration 1 or 2, characterized in that the first substrate comprises a base substrate forming the first surface and a drive element provided on the base substrate.

[0074] (Composition 4) The first region is formed including the base substrate, The liquid discharge head according to configuration 3, characterized in that the second region includes the base substrate and the drive element.

[0075] (Composition 5) The liquid dispensing head according to any one of configurations 1 to 4, characterized in that the driving element comprises a piezoelectric film, a first electrode provided on one side of the piezoelectric film, a second electrode provided on the other side of the piezoelectric film opposite to the first side, and an insulating film provided on the second electrode.

[0076] (Composition 6) A first recess for forming the pressure chamber is formed on one side of the second substrate. A liquid discharge head according to any one of configurations 1 to 5, characterized in that the pressure chamber is formed by the first recess and the diaphragm through the joining of one surface of the second substrate and the second surface of the first substrate.

[0077] (Composition 7) The liquid discharge head according to configuration 6, characterized in that the second substrate has a pressure chamber opening that penetrates the second substrate and communicates with the pressure chamber.

[0078] (Composition 8) The present invention further comprises a third substrate bonded to the other side of the second substrate opposite to the one side thereof, A flow path communicating with the pressure chamber opening is formed between the third substrate and the second substrate. The liquid discharge head according to configuration 7, characterized in that the third substrate has a flow channel opening formed therein that penetrates the third substrate and communicates with the flow channel.

[0079] (Composition 9) The flow channel opening includes a first flow channel opening and a second flow channel opening connected to a liquid supply means, The liquid discharge head according to configuration 8, characterized in that 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 discharge port from the pressure chamber opening.

[0080] (Composition 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 to the flow path from the first flow path opening is supplied to the second flow path opening, while the liquid supplied to the discharge port is supplied from the pressure chamber opening through the pressure chamber. The liquid discharge head according to configuration 8, characterized in that the liquid supplied to the second flow channel opening flows out to the liquid recovery means.

[0081] (Composition 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 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 to the first flow path from the first flow path opening is supplied to the pressure chamber via the first pressure chamber opening, and then supplied to the second pressure chamber opening, while the liquid supplied to the second pressure chamber opening via the discharge port, The liquid discharge head according to configuration 8, characterized in that the liquid supplied to the second pressure chamber opening flows out from the second flow path opening to the liquid recovery means via the second flow path.

[0082] (Composition 12) A second recess for forming a first channel is formed on one side of the third substrate. The first channel is formed by joining the other surface of the second substrate and the one surface of the third substrate. The liquid discharge head according to configuration 9 or 10, characterized in that the second recess has the first flow channel opening and the second flow channel opening that penetrate the third substrate.

[0083] (Composition 13) A second recess for forming the first channel and a third recess for forming the second channel are formed on one surface of the third substrate. The first channel and the second channel are formed by joining the other surface of the second substrate and the one surface of the third substrate. The second recess has the first flow channel opening that penetrates the third substrate. The liquid discharge head according to configuration 11, characterized in that the third recess has the second flow channel opening that penetrates the third substrate.

[0084] (Composition 14) The first substrate has a step formed on the second surface that communicates with the discharge port so as to surround the discharge port. The liquid discharge head according to any one of configurations 1 to 13, characterized in that the step is formed in a region smaller than the region in which the drive element is formed.

[0085] (Composition 15) The liquid dispensing head according to configuration 14, characterized in that the step is formed by an annular recess formed on the second surface.

[0086] (Composition 16) The liquid dispensing head according to configuration 14, characterized in that the step is formed by an annular protrusion formed on the second surface.

[0087] (Composition 17) A liquid dispensing head according to any one of configurations 1 to 16, characterized in that a protective film is formed on the part that comes into contact with the liquid or the outside air.

[0088] (Composition 18) A liquid dispensing head as described in any of configurations 1 to 17, A conveying means for conveying a recording medium to the liquid discharge head, The system includes a liquid supply means for supplying liquid to the liquid discharge head, A recording apparatus characterized by forming an image on the recording medium by discharging the liquid supplied from the liquid supply means onto the recording medium from the discharge port of the liquid discharge head.

[0089] (Composition 19) The recording device according to configuration 18, further comprising a liquid recovery means for recovering the liquid supplied to the liquid discharge head. [Explanation of Symbols]

[0090] 1 circuit board 2. First substrate 3. Second board 5a surface 5b Reverse side 6 Outlet 7 Vibration plate 8. Pressure chamber 15 Base board 100 liquid dispensing heads 700 Recording device

Claims

1. A first substrate having a discharge port for discharging liquid on a flat first surface, and a drive element on a second surface opposite to the first surface, The first substrate is bonded to the second surface of the first substrate, and a second substrate is formed between it and the second surface of the first substrate, which is configured to supply liquid to a pressure chamber. The liquid discharge head is configured such that the portion of the first substrate forming the pressure chamber has a diaphragm that is displaced by the drive element, and the liquid in the pressure chamber is discharged from the discharge port when the diaphragm is displaced, The diaphragm has a first region surrounding the discharge port and a second region surrounding the first region. The first region includes the drive element, The second surface in the first region protrudes further into the pressure chamber than the second surface in the second region, A liquid dispensing head characterized in that the rigidity of the second region is lower than that of the first region.

2. The liquid dispensing head according to claim 1, characterized in that the second region is formed with a thinner film thickness than the first region.

3. The liquid dispensing head according to claim 1 or 2, characterized in that the first substrate comprises a base substrate forming the first surface and a drive element provided on the base substrate.

4. The first region is formed including the base substrate and the driving element, The liquid dispensing head according to claim 3, characterized in that the second region includes the base substrate.

5. The liquid dispensing head according to claim 1, characterized in that the driving element comprises 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 to the first surface, and an insulating film provided on the second electrode.

6. A first recess for forming the pressure chamber is formed on one side of the second substrate. The liquid discharge head according to claim 1, characterized in that the pressure chamber is formed by the first recess and the diaphragm through the joining of one surface of the second substrate and the second surface of the first substrate.

7. The liquid discharge head according to claim 6, characterized in that the second substrate has a pressure chamber opening that penetrates the second substrate and communicates with the pressure chamber.

8. The present invention further comprises a third substrate bonded to the other side of the second substrate opposite to the one side thereof, A flow path communicating with the pressure chamber opening is formed between the third substrate and the second substrate. The liquid discharge head according to claim 7, characterized in that the third substrate has a flow channel opening formed therein that penetrates the third substrate and communicates with the flow channel.

9. The flow channel opening includes a first flow channel opening and a second flow channel opening connected to a liquid supply means, The liquid discharge head according to claim 8, characterized in that 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 discharge port from the pressure chamber opening.

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 to the flow path from the first flow path opening is supplied to the second flow path opening, while the liquid supplied to the discharge port is supplied from the pressure chamber opening through the pressure chamber. The liquid discharge head according to claim 8, characterized in that the liquid supplied to the second flow channel opening flows out to the liquid recovery means.

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 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 to the first flow path from the first flow path opening is supplied to the pressure chamber via the first pressure chamber opening, and then supplied to the second pressure chamber opening, while the liquid supplied to the second pressure chamber opening via the discharge port, The liquid discharge head according to claim 8, characterized in that the liquid supplied to the second pressure chamber opening flows out from the second flow path opening to the liquid recovery means via the second flow path.

12. A second recess for forming the flow channel is formed on one surface of the third substrate. The flow path is formed by joining the other surface of the second substrate and the one surface of the third substrate. The liquid discharge head according to claim 9 or 10, characterized in that the second recess has a first flow channel opening and a second flow channel opening that penetrate the third substrate.

13. A second recess for forming the first channel and a third recess for forming the second channel are formed on one surface of the third substrate. The first channel and the second channel are formed by joining the other surface of the second substrate and the one surface of the third substrate. The second recess has the first flow channel opening that penetrates the third substrate. The liquid discharge head according to claim 11, characterized in that the third recess has a second flow channel opening that penetrates the third substrate.

14. The first substrate has a step formed on the second surface that surrounds the discharge port and communicates with the discharge port, The liquid discharge head according to claim 1, characterized in that the step is formed in a region smaller than the region in which the drive element is formed.

15. The liquid dispensing head according to claim 14, characterized in that the step is formed by an annular recess formed on the second surface.

16. The liquid dispensing head according to claim 14, characterized in that the step is formed by an annular protrusion formed on the second surface.

17. The liquid dispensing head according to claim 1, characterized in that a protective film is formed on the part that comes into contact with the liquid or the outside air.

18. The liquid discharge head according to claim 1, characterized in that the second region is a region in which the drive element is not provided.

19. The diaphragm further includes a third region in addition to the first and second regions, The second region is a region in which wiring for supplying power to the drive element is provided. The third region is the region that surrounds the second region and is bonded to the second substrate. The liquid dispensing head according to feature 1.

20. The liquid dispensing head according to claim 1, A conveying means for conveying a recording medium to the liquid discharge head, The system includes a liquid supply means for supplying liquid to the liquid discharge head, A recording apparatus characterized by forming an image on the recording medium by discharging the liquid supplied from the liquid supply means onto the recording medium from the discharge port of the liquid discharge head.

21. The recording device according to claim 20, further comprising a liquid recovery means for recovering the liquid supplied to the liquid discharge head.

22. The liquid supply means and the liquid recovery means are configured by a circulation means. The recording device according to claim 21, characterized in that liquid is circulated between the circulation means and the liquid discharge head.

23. A suction means is in close contact with the first surface of the first substrate of the liquid discharge head and sucks liquid from the discharge port, The recording apparatus according to any one of claims 20 to 22, further comprising a wiping means for wiping the first surface of the first substrate of the liquid discharge head.

Images