JP2016093978A - Liquid ejection head and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfy the need of increasing a contraction amount of a pressure chamber for ejection performance improvement and a voltage reduction in a liquid ejection head in which high density two-dimensional arrangement of a discharge port and the pressure chamber is allowed.SOLUTION: In the liquid ejection head, a metal film 502 serving as a support member is provided inside of an air chamber 702 adjacent to a side wall of the pressure chamber 701 to suppress swelling of an outer periphery of the pressure chamber 701 in application of a voltage, thereby increasing the contraction amount of the pressure chamber 701.SELECTED DRAWING: Figure 10

Description

  The present invention relates to a liquid ejection head that ejects liquid from an ejection port using a piezoelectric element, and a manufacturing method thereof.

  2. Related Art Inkjet recording apparatuses that record an image by discharging a liquid such as ink onto a recording medium are known. In general, a liquid discharge head that discharges liquid is mounted on the recording apparatus. As an example of a mechanism for discharging a liquid by a liquid discharge head, a mechanism is known in which a volume of a pressure chamber in which the liquid is stored is contracted by a piezoelectric element. In this mechanism, the pressure chamber is contracted by deforming the piezoelectric element by applying a voltage, and the liquid in the pressure chamber is discharged from a discharge port formed at one end of the pressure chamber.

As one of the liquid discharge heads using such a piezoelectric element, one or two wall surfaces of the pressure chamber are constituted by piezoelectric elements, and the pressure chamber is contracted by shearing deformation of the piezoelectric element by applying a voltage. “Share mode type” is known.
On the other hand, in an inkjet apparatus for industrial use, there is a demand for using a highly viscous liquid. In order to eject a highly viscous liquid, a large ejection force is required for the liquid ejection head. In response to this demand, a liquid ejection head called a “Gould type” has been proposed in which a pressure chamber is constituted by a cylindrical piezoelectric member having a circular or rectangular cross-sectional shape.

  In the Gould type liquid discharge head, the piezoelectric member is contracted in the circumferential direction with respect to the center of the pressure chamber by voltage application, and is expanded in the radial direction. That is, the inner periphery of the piezoelectric member constituting the cylindrical pressure chamber shrinks and the outer periphery expands. The Gould type liquid discharge head has all the wall surfaces of the pressure chamber deformed, and the deformation contributes to the liquid discharge force. Compared to the shear mode type in which one or two wall surfaces are formed of piezoelectric elements, A large liquid ejection force can be obtained.

In a Gould type liquid discharge head, in order to record a higher resolution image, it is necessary to arrange a plurality of discharge ports at a higher density. Accordingly, it is necessary to arrange the pressure chambers corresponding to the respective discharge ports at high density.
Therefore, Patent Document 1 discloses a manufacturing method of a Gould type liquid discharge head in which a plurality of discharge ports and pressure chambers are arranged at high density by laminating a plate of piezoelectric material in which a plurality of grooves are formed. Yes.

  Further, although it is a bend mode type patent instead of a Gould type, Patent Document 2 proposes a method in which the contraction amount of the pressure chamber can be increased so that a larger discharge force is generated. In this method, a plurality of grooves are formed in a substrate of piezoelectric material, an electrode film is formed inside the grooves, and then an insulating film is placed on the surface of the substrate on which the grooves are formed to form a pressure chamber. Then, the substrate between the pressure chambers is slit so that the pressure chambers and the slits are alternately arranged, and the conductive paint is formed on the slits, thereby increasing the contraction amount of the pressure chambers by the bimorph effect. It is possible.

JP 2012-144038 A JP-A-9-39244 (paragraphs [0072] to [0091])

  In the Gould-type liquid ejection head disclosed in Patent Document 1, a plurality of piezoelectric material plates having a plurality of grooves formed on the upper surface thereof in a substantially parallel manner are stacked and joined on the upper side to thereby form a plurality of grooves on each piezoelectric material plate. Becomes a plurality of cylindrical portions. The plurality of cylindrical portions for each piezoelectric material plate are used as alternately arranged pressure chambers and air chambers, and the air chambers are positioned outside each of the plurality of side walls constituting the pressure chambers. Yes. Therefore, the piezoelectric member interposed between the pressure chamber and the air chamber is not pressed from either chamber side. On the other hand, since the side walls of the pressure chambers are connected to each other, a binding force is generated at the connecting portion. Due to such a configuration, when a voltage is applied to the side wall of the pressure chamber made of a piezoelectric member, there is a problem that the outer circumference of the pressure chamber is likely to bulge and the pressure chamber is not easily contracted.

  On the other hand, the liquid discharge head disclosed in Patent Document 2 has a configuration in which a pressure chamber is formed by placing an insulating film on the surface of a substrate on which a groove is formed. In this configuration, when the substrates are stacked in order to two-dimensionally arrange the pressure chambers at high density, the insulating film on the substrate becomes an obstacle to the stacking. Further, when the substrates are stacked with the insulating film attached, the structure around the pressure chamber is constrained by the insulating film, and the pressure chamber is unlikely to contract.

  Accordingly, an object of the present invention has been made in view of the above-described problems. The discharge ports can be arranged at high density, the pressure chamber has high rigidity, and large liquid discharge is achieved by suppressing the expansion of the outer periphery of the pressure chamber. It is an object of the present invention to provide a liquid discharge head capable of obtaining force.

One aspect of the present invention includes a discharge port for discharging a liquid and a pressure chamber for storing the liquid discharged from the discharge port, and a side wall constituting the pressure chamber in the liquid supply direction is a piezoelectric element. It is a liquid discharge head comprised by these. In the liquid discharge head of this aspect, the present invention includes a plurality of pressure chambers and a plurality of openings arranged around the side walls of each pressure chamber in a cross section intersecting the liquid supply direction of the liquid discharge head. And an electrode is provided on at least a part of the inner surface of the opening, and a support member for supporting the side wall is provided inside the opening.
Another aspect of the present invention is a method for manufacturing a liquid discharge head, comprising preparing a plurality of substrates made of a piezoelectric body and forming a plurality of grooves in parallel on the surface of each substrate, A step of forming electrodes on the inner surface of the groove, a step of filling a support member for supporting the side wall of the groove every other groove, and the support member of the plurality of grooves is not filled And a step of laminating a plurality of substrates so that the groove serves as a pressure chamber.

  According to the present invention, in a piezoelectric body including a plurality of pressure chambers and a plurality of openings (air chambers) arranged around the side walls of each pressure chamber, the inside of the opening adjacent to the side walls of the pressure chambers. By providing the support member on the surface, it is possible to suppress the expansion of the outer periphery of the pressure chamber when a voltage is applied, and to increase the contraction amount of the pressure chamber. As a result, a liquid discharge head having good discharge performance can be provided.

1 is an overall configuration diagram of a liquid ejection head according to an embodiment. It is a flowchart which shows the manufacturing process of an inkjet head. It is a figure which shows the structure of a piezoelectric substrate. It is a figure explaining the processing procedure of a piezoelectric substrate. It is a figure explaining electrode formation by lift-off. It is a figure explaining the polarization process of a piezoelectric substrate. It is a figure explaining support member formation in an air chamber. It is a block diagram of the piezoelectric block body by which the piezoelectric substrate was laminated | stacked. It is a figure explaining the method to cut | disconnect the side surface of a piezoelectric block body, and isolate | separate into a chip | tip. It is a figure explaining contraction of a pressure chamber. It is a figure explaining the support member formation in the air chamber of 2nd embodiment. It is a figure explaining the support member formation in the air chamber of 3rd embodiment. It is a figure explaining the support member formation in the air chamber of 4th embodiment. It is a figure explaining the support member formation in the air chamber of 5th embodiment. It is a block diagram of the piezoelectric block body by which the piezoelectric substrate of 5th embodiment was laminated | stacked.

Embodiments of a liquid discharge head to which the present invention can be applied will be described below with reference to the drawings. In addition, this invention is not limited by embodiment described below.
[First embodiment]
(Configuration of liquid discharge head)
FIG. 1 is a perspective view and a side view showing the entire configuration of the liquid ejection head according to the first embodiment of the present invention, and shows an exploded state for easy understanding of the configuration. The liquid discharge head includes an orifice plate (also referred to as discharge port plate) 101, a piezoelectric block body 103, a rear diaphragm plate 104, and a common liquid chamber 106.

  The nozzle plate 101 is made of silicon, polyimide, or the like, and the nozzle plate 101 has an ejection port 102 through which liquid is ejected. The piezoelectric block body 103 is formed by laminating a plurality of piezoelectric substrates each having a groove formed therein, and a pressure chamber in which an electrode is formed and filled with a liquid, and an opening (both air chamber) in which the electrode is formed. And) are provided. The piezoelectric block body 103 is provided with a common electrode wiring cable 109 such as FPC in order to draw out the common electrode of the piezoelectric block body 103. The rear throttle plate 104 is made of a silicon substrate or the like, a throttle hole 105 for preventing the pressure generated in the pressure chamber from escaping to the common liquid chamber 106 side, wiring for drawing out individual electrodes on the inner wall of the pressure chamber 106, Is formed. An individual electrode wiring cable 110 such as an FPC is connected to a wiring for drawing out the individual electrode formed on the rear diaphragm plate 104. The liquid 107 such as ink is supplied from the liquid supply port 108 into the common liquid chamber 106.

Below, the manufacturing method of the liquid discharge head of this embodiment is demonstrated. An outline of the manufacturing method is shown in the flowchart of FIG. In the present embodiment, a liquid discharge head capable of recording an image with a resolution equivalent to 1200 dpi (dot per inch) will be described as an example. However, even when the recording resolution is different, the dimensions of the grooves and the number of stacked piezoelectric substrates are changed. Thus, it can be manufactured in the same process.
"Configuration of piezoelectric block body 103"
In the liquid discharge head according to the present embodiment, the discharge ports 102 are arranged two-dimensionally obliquely with respect to the longitudinal direction of the nozzle plate 101 (FIG. 1). The liquid discharge head forms an image on a recording medium (for example, paper or resin sheet) conveyed in the direction in which the piezoelectric substrates of the piezoelectric block body 103 are laminated.

FIG. 3 is a diagram for explaining the piezoelectric substrate 301 constituting the piezoelectric block body 103. As shown in FIG. 3A, the piezoelectric substrate 301 is a piezoelectric plate having a first main surface S1 and a second main surface S2, and a large number of first grooves 302 are formed on the first main surface S1. And second grooves 303 are alternately formed. The first groove 302 constitutes a pressure chamber, and the second groove 303 constitutes an air chamber. In the drawing, the pressure chamber portion is indicated by “P” and the air chamber portion is indicated by “A”.
FIG. 3B is a cross-sectional view showing the shape of the groove and the electrode of the piezoelectric substrate 301. On the inner surface of the groove and the back side of the surface where the groove is processed, a strip-shaped electrode is formed in parallel to the groove. ing. Specifically, an individual electrode 304 (first in-groove electrode) is formed on the inner surface of the first groove 302 constituting the pressure chamber, and is opposed to the second groove 303 on the second main surface S2. An individual electrode 307 (first back electrode) is formed at the position. The individual electrode 307 is defined at the same potential as the individual electrode 304. A common electrode 305 (second in-groove electrode) is formed on the inner surface of the second groove 303, and the individual electrode 306 (second back surface) is formed at a position facing the first groove 302 of the second main surface S2. Electrode). The common electrode 305 is defined at the same potential as the common electrode 306.
The optimum cross-sectional shape of the pressure chamber and the thickness of the side wall of the piezoelectric body around the pressure chamber are obtained by simulation in accordance with the characteristics of the liquid to be discharged, and the dimensions of each part of the piezoelectric substrate 301 are determined so as to realize this. It is decided. The thickness of the piezoelectric substrate 301 is about 0.305 mm. The depth L1 of the groove is 0.12 mm, the widths W1 and W3 of the first groove 302 constituting the pressure chamber and the second groove 303 constituting the air chamber are both 0.06 mm, and the width of the side wall around the pressure chamber is The thicknesses W2 and W4 are both 0.0669 mm.
The interval between the first grooves 302 constituting the pressure chamber is set to n times (n is an integer) the recording dot lattice size corresponding to a resolution of 1200 dpi = 21.15 μm. Necessary resolution can be realized by stacking n layers (n is a natural number) of piezoelectric substrates 301 while sequentially shifting the lattice dimensions by lattice dimensions. In the embodiment, n = 12.

“Processing of piezoelectric substrate 301 (see FIG. 2)”
FIG. 4 is a perspective view for explaining a process for forming grooves and forming electrodes on the piezoelectric substrate 301. For the sake of easy understanding, the width and interval of the grooves and the width and interval of the electrodes are enlarged to several times the actual size. An example of the piezoelectric substrate 301 is a 57 mm × 74 mm × about 0.305 mm PZT (lead zirconate titanate) substrate.

(Back electrode formation: Fig. 2)
First, in the step of FIG. 4A, a flat piezoelectric substrate 301 having a desired thickness and shape is prepared.
In the step of FIG. 4B, the back surface alignment mark 401 made of a metal film, the individual electrode 307, and the common electrode 306 are simultaneously formed on the second main surface S2 (back surface) of the piezoelectric substrate 301. The pattern of the individual electrode 307 and the common electrode 306 is formed in parallel to the longitudinal direction of the groove formed on the first main surface S1 (front surface). Further, in order to apply a voltage to all the electrodes at the time of polarization processing, all the common electrodes 306 are connected by the electrode 402 at the end, and all the individual electrodes 307 are connected by the electrode 403 at the opposite end.
The patterning of the back surface alignment mark 401 and both electrodes can be realized by a method such as lift-off or etching using photolithography of a photoresist, or a method of removing unnecessary portions by laser, dicing, milling, or the like. In this step, since there is no unevenness on the surface of the substrate, a uniform resist film can be formed even by resist application by ordinary spin coating.
Next, the resist is patterned by exposure and development. The resist is patterned by photolithography so that the resist remains in a portion where the electrode pattern is not left by lift-off. Next, a metal layer to be an electrode is formed on the entire surface including the resist pattern by vapor deposition. Vapor deposition is excellent in the ease of patterning by lift-off. Next, by removing the resist, the metal film formed on the resist is peeled off together with the resist, and a desired metal film pattern is finally obtained.
In order to form an electrode, Cr is formed to a thickness of about 20 nm and Pd is formed to a thickness of about 50 nm, and patterning is performed. Further, Ni plating is formed to a thickness of about 1000 nm using Pd as a seed layer, and Ni on the surface is replaced with Au. The plating method is thin because the film thickness at the time of lift-off is thin, so that burrs are less likely to remain and the patterning property is improved, and since Au is used only on the surface, the cost is low.

(Surface alignment mark formation: Fig. 2)
In the step of FIG. 4C, the groove is processed on the groove forming surface (first main surface S1) of the piezoelectric substrate 301, and the surface alignment mark 404 is formed. The surface alignment mark 404 is made of a metal film and is used for alignment at the time of groove processing and lamination. The patterning method and the metal film forming method are the same as those for the individual electrode 307 and the common electrode 306.

(Pressure chamber grooving: Fig. 2)
The groove processing is performed by positioning the groove on the basis of the alignment mark 404 on the surface formed in the previous step. Specifically, in the step of FIG. 4D, a plurality of first grooves 302 are formed in parallel on the flat piezoelectric substrate 301. The first groove 302 formed in the piezoelectric substrate 301 constitutes a part of the pressure chamber of the liquid discharge head described above. In the present embodiment, when cutting, the superabrasive wheel is pulled up on the piezoelectric substrate 301 to form a groove in which one of the two side surfaces facing the groove forming direction does not open. Specifically, as shown in FIG. 4D, the first groove 302 passes through the first end face 405 and does not pass through the second end face 406. By forming grooves on both outer sides in addition to the grooves serving as pressure chambers, it can function as an adhesive escape groove in a subsequent piezoelectric substrate bonding step (not shown in FIG. 4).

(Opening (air chamber) groove processing: Fig. 2)
4E, a plurality of second grooves 303 are formed in parallel on the piezoelectric substrate 301 on which the first grooves 302 are formed. The second groove 303 formed in the piezoelectric substrate 301 constitutes a part of the air chamber of the liquid discharge head described above. The second groove 303 is formed between the adjacent first grooves 302. The second groove 303 also becomes a groove in which one of the two side surfaces facing the groove forming direction is not opened by pulling up the superabrasive wheel halfway on the piezoelectric substrate during the cutting process. However, the opening of one end in the longitudinal direction of the second groove 303 is opposite to the direction of the end of the first groove 302 that is open. Specifically, as shown in FIG. 4E, the second groove 303 penetrates the second end surface 406 and does not penetrate the first end surface 405.

(Surface electrode formation: FIG. 2)
In the step of FIG. 4F, the individual electrode 304 is formed on the inner surface of the formed first groove 302, and the common electrode 305 is formed on the inner surface of the second groove 303. The patterning of the electrode can be formed by lift-off, laser or polishing patterning, or the like. As an example, FIG. 5 shows an electrode patterning method by lift-off. 5A to 5D are cross-sectional views taken along the line AA ′ of FIG. These cross-sectional views show cross sections intersecting with the liquid supply direction in the liquid discharge head. FIG. 5E is a BB ′ cross section of FIG. Since unevenness is generated on the substrate surface by the groove processing, it is difficult to form a uniform resist film by a coating method using a normal spin coater. Therefore, film resist laminating and application by a spray coater are preferably used. Since it is difficult to uniformly expose the inside of the groove, it is preferable to use a negative type resist that only needs to expose the outside of the groove.

First, the film resist 501 is laminated on the piezoelectric substrate 301 in the step of FIG. Since the piezoelectric substrate 301 is a sintered body, voids of about 10 μm are scattered. Therefore, if the film resist 501 is too thin, a pattern defect will occur in the film portion above the void. Therefore, it is preferable to use a film resist 501 having a sufficient thickness, for example, 40 μm or more.
Next, in the process of FIG. 5B, patterning of the film resist 501 is performed by exposure and development. A resist pattern is formed by photolithography so that the resist remains in a portion where the electrode pattern is not left by lift-off. At this time, it is preferable that the pattern width of the resist is slightly smaller than the wall width so that the metal layer is formed on the entire side wall of the groove in the subsequent step. In the step of FIG. 5C, a metal layer to be an electrode is formed on the entire surface including the resist pattern by sputtering or vapor deposition. Sputtering is excellent in film formation on the groove side wall, and vapor deposition is excellent in the ease of patterning by lift-off.
Then, by removing the resist in the step of FIG. 5D, the metal film formed on the resist is peeled off together with the resist, and a desired metal film pattern is finally obtained. As the electrode underlayer, for example, Cr can be formed to a thickness of about 20 nm, and Au can be formed to a thickness of about 1000 nm as the electrode layer. Alternatively, Cr can be formed as a base layer with a thickness of about 20 nm, and Pd can be formed with a thickness of about 50 nm, followed by patterning, and Ni plating with Pd as a seed layer can be formed with a thickness of about 1000 nm. In particular, the latter plating method is thin because the film thickness at the time of lift-off is thin, so that burrs are hardly left and the patterning property is improved, and Au is used only on the surface, so that the cost is low.
When using laser or polishing, a metal film is first formed on the entire surface by sputtering, vapor deposition, electroless plating, or the like. Then, an unnecessary portion of the formed metal film, that is, the metal film on the upper surface portion of the groove forming surface is removed by laser or polishing, whereby a desired electrode pattern can be obtained.
All the individual electrodes 304 and the individual electrodes 307 are in a conductive state via a metal film formed on the first end face 405. In addition, all the common electrodes 305 and the common electrode 306 are in a conductive state through a metal film formed on the second end face 406.

(Polarization: Fig. 2)
As shown in FIG. 6A, the piezoelectric substrate 301 is polarized by applying the common electrodes 305 and 306 to the ground potential and applying a positive voltage to the individual electrodes 304 and 307. FIG. 6B shows an electric field applied to the piezoelectric substrate 301. The polarization is performed by applying a high electric field of about 1 to 2 kV / mm to the piezoelectric body for a predetermined time while being heated to about 100 to 150 ° C.
The distance between the electrodes on the side walls is as narrow as 0.0669 mm or less, and when a high electric field of 1 to 2 kV / mm is applied in the air, there is a high possibility of causing air discharge or creeping discharge. For this reason, it is desirable to perform the polarization treatment in an oil having high insulation properties such as silicone oil (dielectric breakdown voltage: 10 kV / mm or more). Silicone oil can be removed after polarization by a hydrocarbon solvent such as xylene, benzene or toluene, or a chlorinated hydrocarbon solvent such as methylene chloride, 1.1.1.1-trichloroethane or chlorobenzene.
After polarization, an aging process is performed as necessary. Specifically, the piezoelectric characteristics are stabilized by holding the piezoelectric substrate 301 that has been subjected to the polarization treatment in a heated state for a certain period of time. Aging is performed, for example, by leaving the piezoelectric substrate 301 subjected to the polarization treatment in an oven at 100 ° C. for 10 hours.

(Forming a support member in the air chamber groove)
FIG. 7 is a diagram illustrating a process of filling the support member into the groove 303 serving as an air chamber. 7A to 7D are cross-sectional views taken along line AA ′ in FIG.
First, similarly to FIG. 5A, the film resist 501 is laminated on the piezoelectric substrate 301 in the step of FIG. Next, in the process of FIG. 7B, patterning of the film resist 501 is performed by exposure and development. A resist pattern is formed by photolithography so that the film resist 501 covering the groove 302 forming the pressure chamber remains. In the step of FIG. 7C, sputtering, vapor deposition, electroless plating or the like is performed on the entire surface of the piezoelectric substrate, and the groove 303 is filled with a metal material, and at the same time, a metal film 502 is formed. Here, the amount of metal embedded in the groove 303 may not be perfect. 7D, excess metal on the surface of the piezoelectric substrate 301 is removed by polishing or laser irradiation.

“Assembly of piezoelectric block 103 (see FIG. 2)”
A plurality of piezoelectric substrates 301 processed as described above are prepared and stacked, and the piezoelectric block body 103 is formed.
The positional relationship when the piezoelectric substrates 301 are bonded together and the positional relationship between the pressure chamber 701 and the air chamber 702 formed by bonding will be described with reference to FIG. The air chamber 702 is embedded with metal.
In this embodiment, the liquid ejection head is configured by laminating 12 layers of the piezoelectric substrate 301 by setting the pitch in the x direction of the first groove 302 to 12 times the recording dot lattice dimension, so that the piezoelectric substrate 301 adjacent in the y direction is formed. The first grooves 302 are stacked while being shifted by L2 = 0.1269 mm in the x direction. By laminating in this way, the pressure chamber 701 formed by the first groove 302 becomes near the center of the air chamber 702 formed by the second groove 303 of the piezoelectric substrate 301 adjacent in the y direction.
When the piezoelectric block body 103 is formed, as shown in FIG. 8B, n + 1 = 13 piezoelectric substrates 301 are stacked, and an air chamber 702 and a piezoelectric substrate 301-1 are formed below the first piezoelectric substrate 301-1. There is a method in which a lower reinforcing plate 703 formed with a groove is joined, and an upper reinforcing plate 704 without a groove is joined on the 13th layer piezoelectric substrate 301-13. In this case, the 13th piezoelectric substrate 301-13 uses only the air chamber 702 and the pressure chamber 701 is not driven.
In addition, as shown in FIG. 8 (c), n = 12 piezoelectric substrates 301 are laminated, and a lower reinforcement is formed by forming a groove to be an air chamber 702 under the first piezoelectric substrate 301-1 of the laminated body. The plates 703 are joined, and a 0.185 mm electrode is formed on the piezoelectric substrate 301 of the 12th layer, and a polarized piezoelectric element 705 without groove processing is laminated. Further, there is a method of joining an upper reinforcing plate 706 in which a groove to be an air chamber 702 is formed on the piezoelectric element 705. In this case, reinforcing plates 701 and 706 having the same shape with grooves formed in the uppermost and lowermost portions of the piezoelectric block body 103 can be used upside down. The non-driven pressure chambers formed above and below the piezoelectric block body 103 can be used as a recovery channel 707 for circulating the liquid.
Note that the number following the reference numeral 301 in the figure via a hyphen indicates the number of layers of the plurality of layers of the piezoelectric substrate 301.

(Lamination of piezoelectric substrate: Fig. 2)
For bonding of the piezoelectric substrate 301, for example, an epoxy-based adhesive can be used. At this time, it is necessary to appropriately control the amount of the adhesive in order to prevent the groove from being filled with the adhesive. As a method for applying the adhesive, a thin uniform adhesive layer was formed on another flat substrate by spin coating or screen printing, and the surface to be bonded to the piezoelectric substrate 301 was pressed against the flat substrate. Thereafter, a thin and uniform adhesive layer can be formed on the piezoelectric substrate 301 by separating from the flat substrate. After applying the adhesive, the piezoelectric substrate 301 is positioned and pressed and bonded in a state where there is a minute interval. As a measure of the thickness of the adhesive, it is appropriate that the thickness of the adhesive layer before bonding is about 4 μm and the thickness after bonding is about 2 μm.
In order to suppress the intrusion of the adhesive into the pressure chamber 701 and the air chamber 702, grooves are formed outside the plurality of rows of the first grooves 302 and the plurality of rows of the second grooves 303 so as to release the adhesive. It is also effective to use.
At the time of stacking, camera alignment is performed. As marks used for alignment, chip edges, grooves, back and front alignment marks patterned during electrode formation, and the like can be used. As described above, a plurality of piezoelectric substrates 301 are stacked and bonded to form a stacked body, and then a reinforcing plate is bonded so as to sandwich the stacked body from above and below, whereby the piezoelectric block body 103 is manufactured. The reinforcing plate does not need to be a piezoelectric body, but is preferably formed of a material having a thermal expansion coefficient close to that of the piezoelectric substrate 301 when heating is required during bonding.

  By laminating the piezoelectric substrate 301, the bottom surface of the second groove 303 constituting the air chamber is joined to the first groove 302 to form a closed pressure chamber 701. Individual electrodes 304 and 307 are formed. On the second groove 303, the back surface of the bottom of the first groove 302 constituting the pressure chamber is joined to form a closed air chamber 702, and common electrodes 305 and 306 are formed on the inner surface thereof. . The individual electrodes 304 and 307 are conductive at the wiring portion at the end of the piezoelectric block body 103, and are not necessarily conductive by this bonding. For this reason, the width of the individual electrode 307 and the width of the first groove 302 need not be the same. The width of the individual electrode 307 may be slightly narrower than the width of the first groove 302, but the width of the individual electrode 307 is preferably wider in consideration of misalignment during bonding. Similarly, the width of the common electrode 306 may be somewhat narrower than the width of the second groove 303, but it is preferable that the width of the common electrode 306 is wider in consideration of misalignment during bonding.

(Side cut: Fig. 2)
As described above, since the piezoelectric block body 103 is formed by laminating the piezoelectric substrate 301 while shifting, the side surfaces are not flat. Therefore, in order to flatten the side surfaces, both side surfaces are cut out as shown in FIG. Cutting is generally used as a cutting method.

(Chip separation: Fig. 2)
After cutting off both side surfaces of the piezoelectric block body 103, as shown in FIG. 9B, the piezoelectric block body 103 is cut into a plurality of chips having the required pressure chamber length. Cutting is generally used as a cutting method. The longer the pressure chamber length, the greater the volume change of the pressure chamber when the drive voltage is applied and the greater the ejection force, but the lower the pressure responsiveness to the drive voltage waveform, the lower the viscosity of the liquid to be ejected and the ejection liquid. The optimum value is determined by the drop volume. In this embodiment, since the small droplets are ejected, priority is given to responsiveness, and the piezoelectric block body 103 is cut so that the length of the pressure chamber is 3 mm. When the viscosity of the liquid is high and priority is given to the discharge force, it is preferable to lengthen the length of the pressure chamber to 4 to 10 mm.
By separating both ends of the piezoelectric block body 103 in the length direction of the pressure chamber, an end electrode 403 (FIG. 4) connecting the individual electrodes on the back surface for polarization and a first end surface 405 (FIG. 4). ) And the non-grooved portion formed by pulling up the superabrasive wheel when the first groove 302 is formed are separated from each other. Similarly, by raising the superabrasive wheel during the formation of the end electrode 402 connecting the common electrodes on the back surface, the metal film formed on the second end surface 406, and the second groove 304. The generated groove-unformed part is cut off. As a result, the pressure chamber 701 and the air chamber 702 become through holes that open at both ends of the piezoelectric block body 103 described above. At this stage, a pressure chamber having a first groove inner electrode and a first back electrode formed on the inner surface and having a liquid inlet opening and an outlet opening is formed. Similarly, an air chamber in which the second groove inner electrode and the second back electrode are formed on the inner surface is formed.

(End face polishing: Fig. 2)
The both end surfaces of the piezoelectric block body 103 where the pressure chamber 701 and the air chamber 702 are exposed are flattened by polishing. A grindstone can be used for polishing. For the subsequent electrode formation step, the surface roughness is preferably about 0.4 μm arithmetic mean roughness Ra. Further, in order to attach the nozzle plate 101 and the rear diaphragm plate 106 to both end faces of the piezoelectric block body 103 with high accuracy, the flatness of each end face is preferably within 10 μm and the parallelism between the end faces is preferably within 30 μm.

(Electrode formation / adhesion: Fig. 2)
Next, electrodes are formed on the front end face of the piezoelectric block body 103 to draw out the wirings of the common electrodes 305 and 306 provided in the air chamber 702.
Next, rear end surface electrodes are formed on the rear end surface of the piezoelectric block body 103 to draw out the wirings of the individual electrodes 304 and 307 provided in each pressure chamber 701. Since there are irregularities such as the pressure chamber 701 and the air chamber 702, the electrode patterning on the rear end surface is formed by lift-off using a film resist laminate in the same manner as the front end surface. In electrode patterning, a film resist 501 is laminated, and then the periphery of the pressure chamber 701 is exposed by exposure and development. The subsequent electrode generation is the same as the formation of the electrode on the surface of the piezoelectric substrate 301 and the formation of the front end face electrode 712.
The nozzle plate 101 is bonded to the front end surface of the completed piezoelectric block body 103, and the rear diaphragm plate 106 is bonded to the rear end surface, thereby completing the liquid discharge head.

(Liquid discharge drive)
When the piezoelectric block body 103 is deformed by the piezoelectric effect, the pressure chamber 701 contracts, and the liquid stored in the pressure chamber 701 is discharged from the discharge port 102. FIG. 10A shows a state where the drive voltage is applied. The indication “+” in the pressure chamber 701 indicates that a positive drive voltage is applied to the individual electrodes 304 and 307 in the pressure chamber 701. Similarly, “GND” in the air chamber 702 indicates that 0 V of the ground potential is applied to the common electrodes 305 and 306 in the air chamber 701.
FIG. 10B is an enlarged view of the broken line frame in FIG. 10A and shows a state in which the pressure chamber 701 is deformed by application of the drive voltage. In the liquid discharge head manufactured as described above, the metal functions as a support member that supports the side wall of the pressure chamber 701 from the outside by filling the air chamber 702 with metal. As a result, when the side wall of the pressure chamber 701 is expanded and contracted by applying a driving voltage between the individual electrode and the common electrode, as shown by the broken line in FIG. The side wall made of the piezoelectric substrate is restrained and deformed so as to be biased in the direction in which the pressure chamber 701 contracts. As a result, the amount of displacement for contracting the pressure chamber 701 can be increased. In order to facilitate understanding, the displacement amount magnification is increased.

Table 1 shows a comparison table of the simulation results of the pressure chamber shrinkage due to the difference in the filling amount of the members filled in the air chamber 702. This comparison table shows that the air chamber 702 is filled 100% with the filling member (FIG. 10B), 92% filled (FIG. 10C), and 50% filled (FIG. 10B). This is a result of comparing the amount of contraction of the pressure chamber 701 in d)). The shrinkage increase rates of the pressure chamber when compared with the case where the air chamber 702 is not filled were 0.4%, 3.0%, and 6.2%, respectively. It can be seen that the shrinkage amount of the pressure chamber is larger when the filling rate is lower, that is, when there is a gap. Therefore, the lower the filling rate, the higher the effect of suppressing the expansion of the outer periphery of the pressure chamber 701 and not hindering the contraction of the pressure chamber 701 in the circumferential direction. For this reason, it can be said that the filling rate in the air chamber 702 is preferably not 100%.
As described above, by filling the air chamber 702 with the support member, it is possible to suppress swelling of the outer periphery of the pressure chamber 701 when a voltage is applied between the individual electrode and the common electrode. A large contraction amount of the chamber 701 can be expressed, and a large discharge force can be realized.
Note that the Young's modulus of the support member provided in the pressure chamber 701 is desirably 10 GPa or more.

[Second Embodiment]
The configuration of the liquid ejection head according to the second embodiment of the present invention will be described.
The difference from the first embodiment is a step of filling the support member into the groove 303 which becomes the air chamber 702, and the step will be described. Since other parts are the same as those of the first embodiment, a description thereof will be omitted.
(Forming a support member in the air chamber groove)
In FIG. 11, the figure explaining the process of filling a groove | channel used as an air chamber with a supporting member in 2nd embodiment is shown. 11A to 11C are AA ′ cross-sections of FIG.
In the step of FIG. 11A, the resist ink 503 is dispensed. Therefore, the resist ink 503 is filled up in the groove 302 forming the pressure chamber 701 so that the resist ink 503 is halved in the groove 303 forming the air chamber 702. Next, in the step of FIG. 11B, the metal film 502 is formed on the entire surface of the piezoelectric substrate by sputtering, vapor deposition, electroless plating or the like, and at the same time, the metal film 502 is embedded in the groove 303. Then, in the step of FIG. 11C, excess metal on the surface of the piezoelectric substrate is removed by polishing or laser irradiation, and the resist 503 in the groove 302 serving as a pressure chamber is removed.
As described above, the groove 303 forming the air chamber is filled with metal. Similar to the first embodiment, in the liquid discharge head formed by stacking the piezoelectric substrates subjected to the filling process in this way, the displacement amount for contracting the pressure chamber can be increased, and as a result, a large discharge force is output. it can.

[Third embodiment]
The configuration of the liquid ejection head according to the third embodiment of the present invention will be described.
The difference from the first embodiment is a step of filling the support member into the groove 303 which becomes the air chamber 702, and the step will be described. Since other parts are the same as those of the first embodiment, a description thereof will be omitted.
(Forming a support member in the air chamber groove)
FIG. 12 is a diagram illustrating a process of filling a support member into the groove 303 serving as an air chamber in the third embodiment. 12A to 12C are cross-sectional views taken along line AA ′ of FIG.
In the step of FIG. 12A, the resist ink 503 is dispensed. Therefore, the resist ink 503 is filled in the groove 302 forming the pressure chamber so that the resist ink 503 is about one third in the groove 303 forming the air chamber. Next, in the step of FIG. 12B, the metal film 502 is formed on the entire surface of the piezoelectric substrate by sputtering, vapor deposition, electroless plating or the like, and at the same time, the metal film 502 is embedded in the groove 303. Then, in the step of FIG. 12C, excess metal on the surface of the piezoelectric substrate is removed by polishing or laser irradiation, and the resist 503 in the groove 302 serving as a pressure chamber is removed.
As described above, the groove 303 forming the air chamber is filled with metal. Similar to the first embodiment, in the liquid discharge head formed by stacking the piezoelectric substrates subjected to the filling process in this way, the displacement amount for contracting the pressure chamber can be increased, and as a result, a large discharge force is output. it can.

[Fourth embodiment]
The configuration of the liquid discharge head according to the fourth embodiment of the present invention will be described.
The difference from the first embodiment is a step of filling the support member into the groove 303 which becomes the air chamber 702, and the step will be described. Since other parts are the same as those of the first embodiment, a description thereof will be omitted.
(Forming a support member in the air chamber groove)
FIG. 13 is a diagram illustrating a process of filling the support member into the groove 303 serving as an air chamber in the fourth embodiment. FIGS. 13A and 13B are cross sections taken along the line AA ′ of FIG.
In the step of FIG. 13A, the water glass 504 is dispensed so that the water glass 504 is about half in the groove 303 forming the air chamber. Next, in the step of FIG. 13B, a strong acid such as hydrochloric acid is injected into the groove 303 into which the water glass 504 has been injected to gel the water glass 504. Then, the gelled water glass 505 is cured by heating. The heating process may be performed after stacking the filled piezoelectric substrates.
As described above, glass is filled in the groove 303 forming the air chamber. Similar to the first embodiment, in the liquid discharge head formed by stacking the piezoelectric substrates subjected to the filling process in this way, the displacement amount for contracting the pressure chamber can be increased, and as a result, a large discharge force is output. it can.

[Fifth embodiment]
A configuration of the liquid discharge head according to the fifth embodiment of the present invention will be described.
The difference from the first embodiment is the step of forming the support member in the groove forming the air chamber, and the step will be described. Since other parts are the same as those of the first embodiment, a description thereof will be omitted.
(Forming a support member in the air chamber groove)
In FIG. 14, the figure explaining the process of filling the groove | channel 303 used as an air chamber with a supporting member in 5th embodiment is shown. A part of the process is shown in perspective view in FIGS. 14A to 14C, and the rest of the process is shown in FIGS. 14D to 14F in the AA ′ cross section in FIG. .
In the process of FIG. 14A, sputtering, vapor deposition, electroless plating, etc. are performed on both surfaces of each of the two first piezoelectric substrates 601 and one metal substrate 603 (for example, Cu) dissolved in the etching solution. Then, a metal film 604 (for example, Au) that does not dissolve in the etching solution is formed.
Next, in the process of FIG. 14B, one sheet of the metal substrate 603 on which the metal film 604 is formed is sandwiched between the two piezoelectric substrates 601 on which the metal film 604 is formed. A metal substrate 603 and two piezoelectric substrates 601 are stacked and bonded. The laminated substrate 605 laminated in this way is cut into strips as in the step shown in FIG.
Further, in the process of FIG. 14D, the etchant is slightly immersed in the two cut surfaces of the laminate 606 in which the multilayer substrate 605 is formed in a strip shape, and the metal substrate 603 on the cut surface is slightly dissolved. Next, in the step of FIG. 14E, electrode patterning is performed on both surfaces of the second piezoelectric substrate 602 as in the step of FIG. 4B. Then, in the process of FIG. 14F, for example, a plurality of strip-like laminates 606 are fitted and positioned in an assembly jig (not shown) and bonded to the second piezoelectric substrate 602 coated with an adhesive. .
A plurality of piezoelectric substrates 301 manufactured as described above (a plurality of strip-shaped laminated bodies 606 arranged in parallel on the second piezoelectric substrate 602) are stacked, as shown in FIG. A piezoelectric block body 103 is formed. The configuration is the same as that of FIG. 8C except for the shape of the filling material filled in the air chamber.
In such a manufacturing method, since the upper and lower electrodes in the pressure chamber 701 and the upper and lower electrodes in the air chamber 702 can be lengthened, the driving force of the upper and lower walls of the pressure chamber 701 is increased. be able to. That is, since the strip-shaped laminate 606 and the second piezoelectric substrate 602 that are separately manufactured are bonded to each other, the width of the electrodes 607 on both surfaces of the second piezoelectric substrate 602 is changed to change the inside of each of the chambers 701 and 702. The upper and lower electrodes can be made longer.
Further, as shown in FIG. 15B, the upper and lower electrodes in the pressure chamber 701 and the air chamber 702 are not formed, but the electrode in the pressure chamber 701 is used as a common electrode, and the electrode in the air chamber 702 is used. It is also possible to drive only the left and right side walls of the pressure chamber 701 by using a configuration in which individual electrodes are provided. As a result, since there is no potential difference between the common electrode in the pressure chamber 701 and the ink, corrosion of the electrode due to the ink can be reduced.
As described above, the support member is formed in the groove 303 forming the air chamber. Similar to the first embodiment, in the liquid discharge head formed by stacking the piezoelectric substrates subjected to the filling process in this way, the displacement amount for contracting the pressure chamber can be increased, and as a result, a large discharge force is output. it can.
“Industrial Applicability”
The present invention is applicable to a printing apparatus, a coating apparatus, or a modeling apparatus that discharges droplets.

102 Discharge port 301 Piezoelectric substrate 302 First groove 303 Second groove 502 Metal film (support member)
505 Gelled water glass (support member)
603 Metal substrate (support member)
701 Pressure chamber 702 Air chamber

Claims (10)

A discharge port for discharging the liquid and a pressure chamber for storing the liquid discharged from the discharge port are provided, and a side wall constituting the pressure chamber in the liquid supply direction is formed of a piezoelectric body. A liquid discharge head,
With respect to the cross section of the liquid discharge head that intersects the supply direction, the liquid discharge head includes a plurality of the pressure chambers and a plurality of openings disposed around the side walls of each of the pressure chambers. With electrodes,
A liquid ejection head, wherein a support member that supports the side wall is provided inside the opening. The liquid discharge head according to claim 1,
The liquid ejection head, wherein the pressure chambers and the openings are alternately arranged in each of a first direction and a second direction intersecting the first direction with respect to the cross section. The liquid discharge head according to claim 1 or 2,
A plurality of substrates made of piezoelectric bodies, in which first grooves constituting a part of the pressure chamber and second grooves constituting a part of the opening are alternately formed in parallel on one surface. Laminated liquid ejection heads. The liquid ejection head according to claim 3,
The substrate includes a first piezoelectric substrate and a plurality of stacked bodies arranged in parallel on the first piezoelectric substrate, and each of the stacked bodies includes a metal substrate serving as the support member, A liquid ejection head, comprising: a second piezoelectric substrate serving as the side wall disposed with the metal substrate interposed therebetween. The liquid discharge head according to any one of claims 1 to 4,
A first electrode is provided on the inner side surface of the pressure chamber, and a second electrode is provided on the inner side surface of the opening, in a direction connecting the first electrode and the second electrode. A liquid ejection head, which is polarized and extends and contracts when the voltage is applied between the first electrode and the second electrode. The liquid discharge head according to any one of claims 1 to 5,
The liquid discharge head, wherein the support member is formed from the side wall of the opening to a wall facing the side wall. The liquid discharge head according to claim 6,
A liquid discharge head, wherein a gap is formed inside the opening. The liquid discharge head according to any one of claims 1 to 7,
A liquid ejection head, wherein the support member has a Young's modulus of 10 GPa or more. The liquid discharge head according to any one of claims 1 to 8,
The liquid discharge head according to claim 1, wherein the support member is a filling material filled in the opening. A discharge port for discharging the liquid and a pressure chamber for storing the liquid discharged from the discharge port are provided, and a side wall constituting the pressure chamber in the liquid supply direction is formed of a piezoelectric body. A method of manufacturing a liquid ejection head, comprising:
Preparing a plurality of substrates made of piezoelectric bodies, and forming a plurality of grooves in parallel on the surface of each substrate;
Forming an electrode on the inner surface of each groove;
Filling every other one of the plurality of grooves with a support member that supports the side walls of the grooves;
Laminating the plurality of substrates so that a groove that is not filled with the support member among the plurality of grooves becomes the pressure chamber.