JP2007181971A - Liquid jet head and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently eject a liquid droplet in a simple structure. <P>SOLUTION: There is disclosed a liquid jet head that ejects a droplet of a liquid from an ejection hole of a nozzle communicating with a pressure chamber by transmitting displacement of a piezoelectric element to a liquid in the pressure chamber. The liquid jet head comprises a nozzle plate made of a resin or a glass in which the volume resistivity of the nozzle is not less than 10<SP>15</SP>Ωm, and a body plate in which a pressure chamber groove to be the pressure chamber communicating with the nozzle formed on the nozzle plate is made of Si or quarts. A first face of the piezoelectric element forms a part of the wall of the pressure chamber contacting the liquid in the pressure chamber. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid discharge head and a method for manufacturing the liquid discharge head.

  The ink jet recording system is one of non-impact recording systems, which can perform high-speed recording and can record on various recording media, and can obtain high-definition images. Because of these advantages, the inkjet recording system has rapidly become widespread while expanding its use in recent years as a recording means for copying machines, photographs, various printing, industrial high-definition patterning as well as printers as computer peripherals. ing.

  A recording head for performing such ink jet recording includes a nozzle for causing a liquid such as ink to fly, and an energy generating means for applying energy for discharging to the liquid such as an ink in a pressure chamber communicating with the nozzle. ing. A liquid discharge head using a piezoelectric element (piezo element), which is an electromechanical conversion element as energy generating means, controls the meniscus of the nozzle tip by the propagation of pressure waves generated by the piezoelectric element and discharges a droplet. Thus, there is known one having a diaphragm for propagating the mechanical energy of such a piezoelectric element to a liquid (see, for example, Patent Document 1).

  Between the diaphragm and the piezoelectric element, an electrode for applying a voltage for deforming the piezoelectric element to generate a pressure wave is disposed. Therefore, there is a problem in that the drive efficiency of the piezoelectric element is reduced because the electrodes and the diaphragm are interposed before the deformation of the piezoelectric element propagates to the liquid to be discharged.

As a method for improving the driving efficiency of the piezoelectric element, in an ink jet printer head including a plurality of ink chambers, a jet port communicating with the ink chambers, and a diaphragm for applying pressure to each ink chamber, The diaphragm is made of a conductive inorganic material, a piezoelectric element is bonded to the diaphragm, and a driving electrode is formed on the piezoelectric element, and a driving voltage is applied between the diaphragm and the driving electrode. There is a method to do (see Patent Document 2).
Japanese Patent No. 3218664 Japanese Patent Laid-Open No. 10-305574

  In Patent Document 1, as a diaphragm, Pyrex (registered trademark) glass having a thickness of 20 μm to 100 μm or 42 alloy (Fe—Ni alloy) formed with a thin film of Si oxide is cited as an example. A piezoelectric element having an electrode is bonded to these diaphragms.

  Further, in Patent Document 2, the vibration element formed before the propagation of the deformation of the piezoelectric element to the liquid to be ejected functions as a piezoelectric element driving electrode. Although it is not necessary to provide this electrode separately, there is a diaphragm formed of a conductive inorganic material.

  The thinner the diaphragm, the more efficiently the deformation of the piezoelectric element can be transmitted to the liquid. Therefore, when the deformation amount of the diaphragm is the same, the driving voltage of the piezoelectric element is lowered. It is fully expected that the responsiveness of the deformation of the piezoelectric element to the application of the driving voltage is improved.

  The present invention provides a liquid discharge head that has a simpler structure and can discharge liquid droplets more efficiently, and a method of manufacturing the liquid discharge head.

  Said subject is solved by the following structures.

1. In a liquid discharge head that discharges liquid droplets from a discharge hole of a nozzle communicating with the pressure chamber by transmitting the displacement of the piezoelectric element to the liquid in the pressure chamber.
A nozzle plate formed of a resin or glass having a volume resistivity of 10 ¹⁵ Ω · m or more;
A body plate in which a pressure chamber groove serving as the pressure chamber communicating with the nozzle formed in the nozzle plate is formed of Si or quartz;
The liquid discharge head according to claim 1, wherein the first surface of the piezoelectric element forms a part of a wall of the pressure chamber in contact with the liquid in the pressure chamber.

  2. 2. The liquid according to 1, wherein the piezoelectric element has one electrode only on the second surface of the piezoelectric element, and includes at least one of Ti and Zr, Pb, and oxygen. Discharge head.

  3. 3. The liquid discharge head according to 1 or 2, wherein the liquid is conductive.

  4). 4. The liquid discharge head according to claim 1, wherein a liquid repellent treatment is performed on an outermost surface of the nozzle where the discharge hole is present.

  5. An electrostatic voltage applying means for generating an electrostatic attraction force by forming an electric field between the liquid in the nozzle and a substrate provided opposite to the surface on which the discharge hole exists; The liquid discharge head according to any one of 1 to 4, wherein:

6). A nozzle that discharges liquid as droplets from the discharge hole, a pressure chamber that discharges from the discharge hole of the nozzle that communicates droplets by pressure change, and pressure generation means that causes a pressure change in the pressure chamber,
A nozzle plate on which the nozzles are formed;
In the method of manufacturing a liquid discharge head, in which the nozzle plate covers and a body plate in which a pressure chamber groove serving as the pressure chamber is formed is joined.
Forming a SiO ₂ film on the opposite surface of the body plate on which the pressure chamber groove is formed;
Forming a first electrode film made of at least one of Pt and Pd preferentially oriented in (100) on the SiO ₂ film;
Forming a piezoelectric film serving as the pressure generating means on the first electrode film using a sputtering method;
Forming a second electrode film on the piezoelectric film;
Removing the member constituting the body plate at the bottom of the pressure chamber groove until reaching the SiO ₂ film;
Removing the SiO ₂ film at the bottom of the pressure chamber groove until reaching the first electrode film;
Removing the first electrode film at the bottom of the pressure chamber groove until reaching the piezoelectric film;
A method for manufacturing a liquid discharge head, comprising:

7). A nozzle that discharges liquid as droplets from a discharge hole, a pressure chamber that discharges from a discharge hole of a nozzle that communicates droplets by pressure change, and pressure generation means that causes a pressure change in the pressure chamber,
A nozzle plate on which the nozzles are formed;
In the method of manufacturing a liquid discharge head, in which the nozzle plate covers and a body plate in which a pressure chamber groove serving as the pressure chamber is formed is joined.
Forming a third electrode film made of at least one of Pt, Ti, Pd, and Zr on a surface of the body plate opposite to a surface on which the pressure chamber groove is formed;
Forming a piezoelectric film serving as the pressure generating means on the third electrode film;
Forming a fourth electrode film on the piezoelectric film;
Performing a polarization treatment of the piezoelectric film by applying a DC voltage between the third electrode film and the fourth electrode film while heating the piezoelectric film;
Removing the member forming the body plate at the bottom of the pressure chamber groove until reaching the third electrode film;
Removing the third electrode film at the bottom of the pressure chamber groove until reaching the piezoelectric film;
A method for manufacturing a liquid discharge head, comprising:

  8). 8. The method of manufacturing a liquid discharge head according to 6 or 7, wherein the body plate is made of Si or quartz.

9. The method of manufacturing a liquid discharge head according to any one of 6 to 8, wherein the nozzle plate is made of a resin or glass having a volume resistivity of 10 ¹⁵ Ω · m or more.

  10. 10. The method of manufacturing a liquid discharge head according to any one of 6 to 9, wherein the piezoelectric film is formed of a material containing at least one of Ti and Zr, Pb, and oxygen.

  11. 11. The method of manufacturing a liquid discharge head according to claim 6, further comprising a step of performing a liquid repellent treatment on an outermost surface of the nozzle where the discharge hole is present.

  12 A liquid discharge head manufactured by the method for manufacturing a liquid discharge head according to any one of 6 to 11.

  13. An electrostatic voltage applying means for generating an electrostatic attraction force by forming an electric field between the liquid in the nozzle and a substrate provided opposite to the surface on which the discharge hole exists; 13. The liquid discharge head according to 12, wherein

  According to the first aspect of the present invention, the first surface of the piezoelectric element is applied to the liquid discharged in the pressure chamber of the body plate formed of Si or quartz that can be easily processed with high accuracy. Can be touched directly. Therefore, the deformation of the piezoelectric element is transmitted to the liquid that is present in the pressure chamber processed with high accuracy and becomes a liquid droplet ejected from the nozzle without any intervening therebetween. Therefore, it is possible to provide a liquid discharge head that has a simpler structure and can discharge droplets more efficiently.

Furthermore, the nozzle plate on which nozzles having discharge holes for discharging liquid as droplets are made of resin or glass having a volume resistivity of 10 ¹⁵ Ω · m or more, so an electric field is applied to the liquid in the pressure chamber. As a result, the electric field strength at the tip of the meniscus formed at the tip of the nozzle with the liquid discharged by deformation of the piezoelectric element can be made large enough to stably discharge the droplet. It can be used as an electrosuction liquid discharge head.

  According to the sixth, seventh, and twelfth aspects of the invention, the bottom of the pressure chamber groove formed in the body plate of the liquid discharge head is directed to the surface opposite to the surface on which the pressure chamber groove of the body plate is formed. There will be a sequentially polarized piezoelectric film, second electrode film, or fourth electrode film. Since the polarized piezoelectric film functions as a piezoelectric element, the bottom surface portion forming the pressure chamber becomes a piezoelectric element, and this piezoelectric element can directly touch the liquid in the pressure chamber. Therefore, the deformation of the piezoelectric element is transmitted to the liquid that is a droplet discharged from the nozzle without any intervening therebetween. Accordingly, it is possible to provide a method of manufacturing a liquid discharge head that has a simpler structure and can discharge liquid droplets more efficiently, and a liquid discharge head manufactured by this manufacturing method.

  Hereinafter, embodiments of a liquid discharge head according to the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating an overall configuration of a liquid ejection apparatus 1 that uses a liquid ejection head 2 (cross-sectional view) as an example of the present embodiment. The liquid discharge head 2 can be applied to various liquid discharge devices such as a so-called serial method or line method.

  The liquid ejecting apparatus 1 includes a liquid ejecting head 2 on which a nozzle 10 for ejecting a droplet D of a chargeable liquid L such as ink is formed, an operation control unit 4, and an opposing surface facing the nozzle 10 of the liquid ejecting head 2. And a counter electrode 3 that has a surface and supports a substrate K that receives the landing of the droplet D on the opposite surface.

  A nozzle plate 11 having a plurality of nozzles 10 is provided on the side of the liquid ejection head 2 facing the counter electrode 3. The liquid discharge head 2 is configured as a head having a flat discharge surface in which the nozzle 10 does not protrude from the discharge surface 12 facing the counter electrode 3 of the nozzle plate 11 or the nozzle 10 protrudes only about 30 μm. In addition, the nozzle 10 may have a polygonal shape, a star shape, or the like instead of being formed into a circular cross-sectional shape. The diameter when the cross-sectional shape is not a circle is the diameter when the cross-sectional area of the target cross-section is replaced with a circle having the same area.

  Each nozzle 10 is formed by being drilled in a nozzle plate 11, and is a through-hole having a discharge hole 13 on a discharge surface 12 of the nozzle plate 11. Here, the nozzle diameter indicates the diameter of the discharge hole 13 of the nozzle 10, and the diameter when the opening shape of the discharge hole is not a circle is the same as the above, but the opening area of the target opening surface is a circle having the same area. The diameter when replaced.

The nozzle plate 11 is a glass having a volume resistivity will be described later, and 10 ¹⁵ Ω · m or more (hereinafter, referred to as a high-resistance glass.) Or a volume resistivity of 10 ¹⁵ Ω · m or more and a resin (hereinafter, a high-resistance resin It is preferable to form the above. As the high resistance glass, for example, quartz, synthetic quartz, high purity glass, or the like may be selected as appropriate. As the high resistance resin, for example, PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PI (polyimide), or the like may be selected as appropriate. It ’s fine.

  A method of preparing the nozzle plate 11 by providing a nozzle on high resistance glass is not particularly limited. For example, a high resistance glass substrate is used and a carbon fluoride gas or a hydrogen fluoride carbon gas is used as a reaction gas. There is a method of performing a dry etching process. Further, a method for producing a nozzle plate by providing a nozzle in a high-resistance resin is not particularly limited, and examples thereof include a resin molding method and a method using a known photolithography technique for a coated resin film.

  In the present embodiment, the inner peripheral surface 17 of the nozzle 10 of the nozzle plate 11 and the bottom surface of the pressure chamber 20 that follows the nozzle 10 are charged by applying a voltage to the liquid L made of a conductive material such as NiP, for example. Accordingly, a charging electrode 16 is provided as an electrostatic voltage applying means for generating an electrostatic attraction force described later. The charging electrode 16 is in contact with the liquid L in the nozzle.

  The charging electrode 16 is connected to an electrostatic voltage power source 18 by a wiring (not shown). When an electrostatic voltage is applied from the electrostatic voltage power source 18 to the charging electrode 16, the liquid L in all the nozzles 10 is discharged. Simultaneously charged, an electrostatic attraction force can be generated between the liquid ejection head 2 and the counter electrode 3, particularly between the liquid L and the substrate K.

  A body plate 19 is provided on the surface of the nozzle plate 11 opposite to the discharge surface 12. A substantially cylindrical space having an inner diameter larger than the opening of the nozzle 10 is formed in the portion of the body plate 19 facing the opening end of each nozzle 10 on the opposite side of the surface where the discharge hole 13 is provided in the nozzle plate 11. Each space is a pressure chamber 20 for temporarily storing the liquid L to be discharged.

In addition, since the body plate 19 can use a processing method according to the semiconductor manufacturing process, it can easily perform highly accurate processing, and can reduce the crosstalk between a plurality of pressure chambers. It is preferably formed from quartz. A pressure chamber 20, a common channel, and a channel connecting the common channel and the pressure chamber 20 are provided using a known photolithography technique (resist coating, exposure, development) and an etching method using a Si substrate or a quartz substrate. be able to. As an etching method in the case of using Si, for example, there is a dry etching method in which the reaction gas is CF _4, and in the case of using quartz, as in the case of the nozzle plate, a carbon fluoride gas or a hydrogen fluoride carbon gas is used. There is a dry etching method using as a reaction gas.

  A common pipe (not shown) is connected to a supply pipe (not shown) for supplying the liquid L from an external liquid tank (not shown), and is supplied by a supply pump (not shown) provided in the supply pipe or depending on the position of the liquid tank. A predetermined supply pressure is applied to the liquid L such as the flow path, the pressure chamber 20 and the nozzle 10 by the differential pressure.

  Here, a piezoelectric element 22 as a piezoelectric element actuator having a thickness of about 1 μm to several tens of μm is formed at the bottom of the pressure chamber 20 and can be deformed so as to generate pressure in the liquid L. .

  The piezoelectric element 22 is provided with the electrode 107 only on one surface, and the other surface is in contact with the liquid L in the pressure chamber 20. The charging electrode 16 is also provided in contact with the liquid L. Here, by making the liquid L conductive, the driving voltage applied by the driving voltage power source 23 for driving the piezo element 22 can be applied between the electrode 107 and the charging electrode 16. Only one of the electrodes 107 can be provided on the element 22.

  Therefore, since the piezo element 22 has the electrode 107 only on one surface, it can be easily deformed even at a low driving voltage, and the deformation in the nozzle 10 is not interposed between them. A pressure can be generated in the liquid L so that the meniscus of the liquid L can be more efficiently formed in the discharge hole 13 of the nozzle 10, and as a result, droplets can be discharged more efficiently. The piezo element 22 will be described in further detail below.

  The drive voltage power supply 23 and the electrostatic voltage power supply 18 that applies an electrostatic voltage to the charging electrode 16 are connected to the operation control means 4, respectively, and are controlled by the operation control means 4.

  The operation control means 4 is composed of a computer in which a CPU 25, a ROM 26, a RAM 27, etc. are connected by a BUS (not shown). The CPU 25 is based on a power control program stored in the ROM 26 and each of the electrostatic voltage power supply 18 and each of them. The drive voltage power supply 23 is driven to discharge the liquid L from the discharge hole 13 of the nozzle 10.

  A liquid repellent layer 28 is provided on the entire discharge surface 12 of the nozzle unit 11 to prevent the liquid L from seeping out from the discharge holes 13. By providing the liquid repellent layer 28, the liquid L is prevented from seeping out from the discharge hole 13, and the liquid meniscus formed in the discharge hole 13 portion of the nozzle 10 is hardly spread on the discharge surface around the discharge hole 13. As a result, it is possible to effectively prevent a reduction in electric field concentration at the meniscus tip.

  For the liquid repellent layer 28, for example, a material having water repellency is used if the liquid L is aqueous, and a material having oil repellency is used if the liquid L is oily. Fluorine resins such as hexafluoropropylene), PTFE (polytetrafluoroethylene), fluorine siloxane, fluoroalkylsilane, and amorphous perfluoro resin are often used, and a film is formed on the discharge surface 12 by a method such as coating or vapor deposition. Has been. The liquid repellent layer 28 may be formed directly on the ejection surface 12 of the nozzle plate 11 or may be formed via an intermediate layer in order to improve the adhesion of the liquid repellent layer 28.

  In the liquid discharge direction of the liquid L of the liquid discharge head 2, a flat counter electrode 3 that supports the substrate K is disposed in parallel to the discharge surface 12 of the liquid discharge head 2 at a predetermined distance. The predetermined distance between the counter electrode 3 and the liquid ejection head 2 is appropriately set within a range of about 0.1 to 3 mm.

  In the liquid ejection apparatus 1 using the liquid ejection head 2 of the present embodiment, the counter electrode 3 is grounded and is always maintained at the ground potential. Therefore, when an electrostatic voltage is applied from the electrostatic voltage power source 18 to the charging electrode 16, an electric field is generated between the liquid L in the ejection hole 13 of the nozzle 10 and the opposing surface of the counter electrode 3 facing the liquid ejection head 2. Has come to occur. When the charged droplet D lands on the substrate K, the counter electrode 3 releases the electric charge by grounding.

  The counter electrode 3 or the liquid ejection head 2 is provided with positioning means (not shown) for positioning the liquid ejection head 2 and the substrate K by relatively moving them. The droplets D discharged from each nozzle 10 can be landed on the surface of the substrate K at an arbitrary position.

  The liquid L ejected by the liquid ejecting apparatus 1 is a conductive liquid, and includes an inorganic liquid, an organic liquid, and a conductive paste containing a large amount of a substance having high electrical conductivity (such as silver powder). Is not particularly limited, except that the above-described high electrical conductivity substance dissolved or dispersed in the inorganic or organic liquid is a coarse particle that causes clogging in the nozzle 10. .

  Here, the piezoelectric element 22 formed at the bottom of the pressure chamber 20 of the liquid discharge head 2 will be described in detail below.

FIG. 2 is an enlarged view showing one pressure chamber 20 in FIG. The side with the pressure chamber 20 of body plate 19, has a SiO ₂ film 101, on the SiO ₂ film 101 having a Pt (platinum) film 103 around the opening of the pressure chamber 20, the A piezoelectric body 105 covering the space of the pressure chamber 20 is provided on the Pt film 103, and an electrode 107 is further provided on the piezoelectric body 105. The formation of such a piezo element 22 on the body plate 19 will be described below.

  As a first embodiment, a method of forming a piezo element without performing a polarization process on the bottom of a pressure chamber will be described with reference to FIG.

  FIG. 3 schematically shows a process of forming a piezo element on the body plate, paying attention to one piezo element. First, using a Si substrate, using a known photolithography technique (resist application, exposure, development) and etching method, a pressure chamber 300, a common channel (not shown), a channel connecting the common channel and the pressure chamber 300, and the like A body plate 301 is formed (FIG. 3A).

Next, an SiO ₂ layer 302 having a thickness of about 0.1 μm to 2 μm is formed on the back surface 301a of the bottom surface of the pressure chamber 300 (FIG. 3B). The method for forming the SiO ₂ layer 302 is not particularly limited, and examples thereof include TEOS (tetraethoxysilane) treatment and thermal oxidation treatment. The SiO ₂ layer 302 may be formed, for example, during the process of forming the pressure chamber 300 and the flow path communicating therewith, without providing the SiO ₂ layer forming process such as the TEOS process as an independent process. There is also. Therefore, the SiO ₂ layer forming step may not be provided as an independent step as necessary.

Next, a Pt (platinum) or Pd (palladium) film 303 preferentially oriented to (100) is formed on the SiO ₂ layer 302 in a region where a piezoelectric element is provided (FIG. 3C). Hereinafter, this film will be described as a Pt film as an example. The Pt (platinum) film 303 preferentially oriented to (100) is formed by a thin film manufacturing apparatus (Japanese Patent Laid-Open No. 6-108242) using a sputtering method disclosed by the present inventors. When the Pt film 303 is formed in the region where the piezo element is provided using this thin film manufacturing apparatus, for example, a deposition mask or the like is preferably used so that the Pt film is not formed in an unnecessary region.

Next, a piezoelectric film 304 serving as a piezoelectric element is formed on the Pt film preferentially oriented to the above (100) (FIG. 3D). This piezoelectric film preferably contains at least one of Ti (titanium) and Zr (zirconium), Pb (lead), and oxygen. The method for forming the piezoelectric film 304 is not particularly limited, and an RF magnetron sputtering method known as a known method for forming a piezoelectric film may be used. The target used to form the piezoelectric film 304 by this RF magnetron sputtering method is a mixture of, for example, PbZr _0.52 Ti _0.48 O ₃ (lead zirconate titanate, 90% by mass) and PbO (lead oxide, 10% by volume). What is being done is mentioned. The temperature of the Si substrate during the formation of the piezoelectric film 304 is preferably about 550 ° C., and the film formation rate is preferably a relatively low film formation rate of about 0.01 μm / min. The orientation of the piezoelectric film 304 formed by the above method can be confirmed by using an X-ray diffraction powder method. This piezoelectric film 304 has a perovskite structure and has a polarization axis. A c-axis oriented epitaxial film is preferentially oriented in the direction perpendicular to the substrate surface. Therefore, it can function as a piezoelectric element without requiring a polarization process.

  Next, a metal film 305 to be an electrode of the piezo element is provided (FIG. 3E). The material for the metal film 305 is not particularly limited as long as it can be used as an electrode, and examples thereof include Pt, Au, and Al. The metal film 305 made of these may be formed directly on the piezoelectric film 304, or an intermediate layer such as Cr (chromium) may be used to improve the adhesion of the metal film 305 to the piezoelectric film 304. May be provided.

Next, the bottom surface of the pressure chamber groove 300 of the body plate 301 is dug until reaching the piezoelectric film 304 (FIG. 3F). First, Si on the bottom surface of the pressure chamber groove 300 is removed until reaching the SiO ₂ layer formed on the back surface. The removal method may be a known method and is not particularly limited. For example, there is an anisotropic dry etching method using ICP (Inductive Coupled Plasma). This removal method is preferable because SiO ₂ can hardly be removed, and etching is stopped after Si removal, so that the removal conditions can be easily set.

Next, the SiO ₂ layer 302 is removed until it reaches the Pt film 303 (FIG. 3G). The method for removing the SiO ₂ layer may be a known method and is not particularly limited. For example, there is a dry etching method using CF ₄ as a reaction gas. Since this removal method hardly removes the Pt film, the etching is stopped after the removal of SiO ₂ , so that the removal conditions can be easily set.

  Further, the Pt film is removed until it reaches the piezoelectric film 304 (FIG. 3 (h)). A method for removing the Pt layer may be a known method and is not particularly limited. For example, there is a plasma treatment method using Ar (argon). Since this plasma treatment is a method that can also remove the piezoelectric film, it is preferable to determine in advance conditions for removing the Pt film that does not cause a defect in the piezoelectric film by experiments or the like.

  When the removal of the Pt film is completed, the formation of the piezoelectric element composed of the piezoelectric film 304 and the electrode 305 on the body plate 301 is completed.

In the Si, SiO _2, and Pt removal processes described above, particularly in the Si removal process, the surface of the body plate 301 on which the pressure chamber groove 300 other than the bottom surface of the pressure chamber groove 300 is formed is also etched. It will be. Therefore, it is only necessary to form a flow channel groove such as the pressure chamber groove 300 in consideration of the removal process, for example, a thickness of the mask at the time of forming the flow channel groove in consideration of the removal process, and remove the mask after removing Si. .

  Next, the liquid ejection head 320 can be completed by joining a nozzle plate 310 having a nozzle prepared separately so as to cover the pressure chamber 300 of the body plate 301.

The nozzle plate 310 may be made of a high resistance glass using, for example, a dry etching method in which a reactive gas is CF ₄ .

  In addition, a charging electrode 314 made of a conductive material such as NiP, Pt, or Au is provided on the inner peripheral surface of the nozzle 312 of the nozzle plate 310 and a portion covering the pressure chamber following the nozzle 312 (FIG. 3 (i)). . The method for providing the charging electrode 314 is not particularly limited, and a known vacuum deposition method, sputtering method, or the like may be used. Further, the conductive material is not limited to the above example, and a material that does not cause corrosion or the like by being in contact with the liquid used for ejection may be selected as appropriate.

  In FIG. 3, a liquid repellent layer 316 is provided on the discharge surface where the nozzle discharge holes 312 are provided.

  This completes the liquid ejection head in the first embodiment.

  As a second embodiment, a method of forming a piezo element by performing a polarization process on the bottom of a pressure chamber will be described with reference to FIG.

  FIG. 4 schematically shows a process of forming a piezo element on a body plate using a sol-gel PZT liquid, paying attention to one piezo element. First, using a Si substrate, using a known photolithography technique (resist application, exposure, development) and an etching method, a pressure chamber 400, a common flow path (not shown), a flow path connecting the common flow path and the pressure chamber 400, and the like. The body plate 401 provided is formed (FIG. 4A).

  A metal film 403 is formed in a region where the piezoelectric element on the opposite surface 401a of the pressure chamber 400 is provided (FIG. 4B). The metal film 403 is preferably Pt, Ti, Pb, Zr and In. This is because it is necessary to be a material that can withstand heat treatment at 500 ° C. or higher for sintering the piezoelectric body to be performed later and does not react with the laminated piezoelectric film. The formation method of this metal film 403 is not specifically limited, For example, well-known methods, such as sputtering method, may be sufficient, and the orientation of the formed metal film is not especially required.

  Next, a film for lift-off, for example, an Al film 402 ′ having a thickness of about 1 μm is formed in a region other than where the metal film 403 is formed (FIG. 4D). This formation method may be formed by performing a known photolithography process and an etching process after the Al film 402 is formed by, for example, a known vacuum deposition (FIG. 4C), and is not particularly limited. Thus, on the back surface of the bottom surface of the pressure chamber groove 400 of the body plate 401, either the metal film 403 or the Al film 402 'is formed.

  Next, a sol PZT liquid, for example, PZT alcoholate (trade name, Inostek) is applied on the Al film 402 ′ and the metal film 403 to form the piezoelectric film 404a (FIG. 4E). . Specifically, for example, a 1 μm-thick piezoelectric film is formed by application by spin coating, and then dried and pre-sintered. The piezoelectric film preferably contains at least one of Ti (titanium) and Zr (zirconium), Pb (lead), and oxygen.

  Next, by performing Al etching, the metal film 403 and the piezoelectric film 404b on the metal film 403 are left on the body plate 401, and the piezoelectric film on the Al film 402 ′ and the Al film 402 ′ is removed (FIG. 4). (F)). After the formation of the Al film 402 and the formation of a 1 μm-thick film by application of a sol PZT solution, the steps of drying and pre-sintering (from FIG. 4C to FIG. 4F) are repeated to obtain the piezoelectric film. Is laminated to obtain a desired thickness of the piezoelectric film. Thereafter, the piezoelectric film 404c can be formed by performing a heat treatment at 500 ° C. or higher for the main sintering. At this time, the piezoelectric film 404c is in a polycrystalline state in which the orientation is not sufficiently aligned.

  Here, the piezoelectric film is formed in the second embodiment by applying a sol PZT solution, but the same RF magnetron sputtering method as in the first embodiment may be used. However, the piezoelectric film formed by the RF magnetron sputtering method has a perovskite structure, and does not become a c-axis oriented epitaxial film in which the polarization axis is preferentially oriented in the direction perpendicular to the substrate surface. The polarization process described in the above is required.

  Next, a metal film 405 serving as an electrode of the piezoelectric element is provided (FIG. 4G). The material for the metal film 405 is not particularly limited as long as it can be used as an electrode, and examples thereof include Pt, Au, and Al. The metal film 405 made of these materials may be formed directly on the piezoelectric film 404c, or an intermediate layer, for example, Cr may be provided to improve the adhesion of the metal film 405 to the piezoelectric film 404c. Also good.

  Next, a piezoelectric material is applied by applying a DC voltage of about 50 V to 100 V between the metal film 403 and the metal film 405 for about 1 hour while heating the portion of the piezoelectric film 404 c at about 200 ° C. to 300 ° C. The membrane is polarized (FIG. 4 (h)). These heating temperature, voltage, and treatment time may be determined in advance through experiments and the like in consideration of the material, thickness, and the like that are the objects of polarization treatment. It can be confirmed by X-ray diffraction that the piezoelectric film after the polarization treatment is preferentially oriented to the c-axis of the perovskite structure. Therefore, the piezoelectric film 404c can function as a piezoelectric element.

  Thereafter (FIGS. 4I to 4L), the liquid ejection head 420 can be completed by performing the same steps as those in the first embodiment.

  This completes the liquid ejection head in the second embodiment.

  In the first and second embodiments, the body plate is made of Si and the nozzle plate is made of high-resistance glass. However, the body plate is made of quartz and the nozzle When the plate is formed from a high-resistance resin or when the combination is changed, the liquid discharge head can be manufactured in the same manner as described above.

The inventors configured the electric field strength of the electric field between the electrodes to be a practical value of 1.5 kV / mm using the liquid discharge experimental apparatus S ′ shown in FIG. In experiments conducted by forming the nozzle plate 11 ′ and based on the following experimental conditions, there were cases where the droplet D ′ was ejected from the nozzle 10 ′ and was not ejected.
[Experimental conditions]
Distance between discharge surface 12 'of nozzle plate 11' and facing surface of counter electrode 3 ': 1.0 mm
Nozzle plate 11 'thickness: 125 μm
Nozzle diameter: 10 μm
Electrostatic voltage: 1.5 kV
Drive voltage: 20V
The nozzle 10 ′ of the experimental liquid discharge head A ′ used in the liquid discharge experiment has a taper angle of 4 °. The taper angle indicates an angle that spreads in a direction away from the discharge surface 12 ′ from a perpendicular to the discharge surface 12 ′ in the cross section of the nozzle 10 ′. The taper angle has a small influence on the ejection, and it is obtained from simulations described later that the dependence on the conditions for ejecting the droplets stably is not large.

  Here, the principle of liquid ejection in the liquid ejection head will be described with reference to FIG. In the experimental liquid ejection head A ′, an electrostatic voltage is applied from the electrostatic voltage power source 63 ′ to the charging electrode 16 ′ as electrostatic voltage application means, and is opposed to the liquid L ′ in the ejection hole 13 ′ of the nozzle 10 ′. An electric field is generated between the facing surface of the electrode 3 ′ facing the experimental liquid ejection head A ′. Further, a driving voltage is applied from the driving voltage power supply 61 ′ to the piezoelectric element 22 ′ as pressure generating means to deform the piezoelectric element 22 ′, and thereby the discharge hole 13 ′ of the nozzle 10 ′ is generated by the pressure generated in the liquid L ′. To form a meniscus of liquid L ′.

  When the insulating property of the nozzle 10 ′ is increased, the equipotential lines are arranged in the nozzle 10 ′ in a direction substantially perpendicular to the ejection surface 12 ′, as shown by the equipotential lines by simulation in FIG. A strong electric field is generated toward the meniscus portion.

  In particular, as can be seen from the fact that the equipotential lines are dense at the tip of the meniscus in FIG. 6, a very strong electric field concentration occurs at the tip of the meniscus. For this reason, the meniscus is torn off by the electrostatic force of the electric field and separated from the liquid L ′ in the nozzle to form a droplet D ′. Further, the droplet D ′ is accelerated by the electrostatic force, and is attracted and landed on the base material K ′ supported by the counter electrode 3 ′. At that time, since the droplet D 'attempts to land closer by the action of electrostatic force, the angle at the time of landing on the substrate K' is stabilized and accurately performed.

  As described above, if the discharge principle of the liquid L ′ in the experimental liquid discharge head A ′ is used, the experimental liquid discharge head A ′ having a flat discharge surface also uses the nozzle 10 ′ portion having high insulation. By generating a potential difference in the vertical direction with respect to the discharge surface 12 ′, strong electric field concentration can be generated, and an accurate and stable discharge state of the liquid L ′ can be formed.

In the experiment using the liquid discharge experimental device S ′, the electric field strength at the tip of the meniscus was obtained for all cases where the droplet D ′ was stably discharged from the nozzle. Actually, since it is difficult to directly measure the electric field strength at the tip of the meniscus, the electric field simulation software “PHOTO-VOLT” (trade name, manufactured by Photon Co., Ltd.) was used for calculation. The electric field strength here refers to the electric field strength 300 seconds after voltage application in the current distribution analysis mode. As a result, in all cases, the electric field strength at the meniscus tip was 1.5 × 10 ⁷ V / m or more. In this experiment, even when the droplet D ′ was not stably ejected from the nozzle, the electric field strength at the meniscus tip was calculated by the same simulation as described above. As a result, it was less than 1.5 × 10 ⁷ V / m.

Further, as a result of calculating the electric field strength at the meniscus tip by inputting the same parameters as the above experimental conditions into the software, as shown in FIG. 7, the electric field strength is the volume resistance of the insulator used for the nozzle plate 11 ′. It turned out to be strongly dependent on the rate. Moreover, in order to stably discharge the droplet D ′ from the nozzle 10 ′, it is obtained from the above experiment that the electric field strength at the tip of the meniscus needs to be 1.5 × 10 ⁷ V / m or more. Therefore, as apparent from FIG. 7, it was found that the volume resistivity of the nozzle plate 11 ′ should be 10 ¹⁵ Ω · m or more.

The characteristic dependence of the electric field strength at the tip of the meniscus on the volume resistivity of the nozzle plate 11 ′ as shown in FIG. 7 can be obtained in the same way even when simulation is performed with various nozzle diameters. In all cases, it is known that the electric field strength at the meniscus tip is 1.5 × 10 ⁷ V / m or more when the volume resistivity is 10 ¹⁵ Ω · m or more.

Therefore, in the liquid discharge head 2 shown in FIG. 1, the nozzle plate 11 is preferably made of resin or glass having a volume resistivity of 10 ¹⁵ Ω · m or more. By using such a resin or glass, the electric field strength at the tip of the meniscus of the droplet formed in the discharge hole 13 becomes 1.5 × 10 ⁷ V / m or more, so that the liquid can be discharged stably. It will be able to be. In addition, when the resin of the nozzle plate 11 absorbs a conductive liquid, the electrical conductivity of the nozzle plate 11 increases, and as a result, the volume resistivity may decrease. In such a case, a liquid absorption preventing layer may be provided on the surface of the nozzle plate 11 that contacts the liquid to be discharged. Specific examples of the glass having a volume resistivity of 10 ¹⁵ Ω · m or more include quartz, synthetic quartz, and high-purity glass.

  Furthermore, when the nozzle 10 ′ of the nozzle plate 11 ′ shown in FIG. 5 has a through hole shape without a taper that has the same diameter as the discharge hole 13 shown in FIG. 2, the thickness of the nozzle plate 11 ′ is 10 μm. FIG. 8 shows a simulation result of the electric field strength at the tip of the meniscus when the nozzle diameter is changed as parameters of 20 μm, 50 μm, and 100 μm.

From FIG. 8, it can be seen that the electric field strength at the tip of the meniscus increases as the nozzle diameter decreases and the thickness of the nozzle plate increases. In order to stably discharge the droplets D ′ from the nozzle 10 ′, the electric field strength at the meniscus tip must be 1.5 × 10 ⁷ V / m or more. In the case of 10 μm, droplets can be stably discharged by setting the nozzle diameter to less than 4 μm. Further, for example, when the nozzle plate thickness is 20 μm, the nozzle diameter is less than 6 μm, when the nozzle plate thickness is 50 μm, the nozzle diameter is less than 11 μm, and when the nozzle plate thickness is 100 μm, the nozzle diameter is When the thickness is less than 24 μm, the droplets can be stably discharged.

In this way, the thickness of the nozzle plate made of resin or glass having a volume resistivity of 10 ¹⁵ Ω · m or more is set to a value appropriately determined from a desired nozzle diameter with reference to FIG. 8 or using the simulation for obtaining FIG. By doing so, it is possible to obtain a liquid discharge head capable of stably discharging droplets.

  In this embodiment, the meniscus formed by deformation of the piezo element 22 is separated by electrostatic attraction force into droplets, accelerated by an electric field due to electrostatic voltage, and landed on the substrate K. In addition to this, for example, it is possible to apply a driving voltage that is strong enough to cause the liquid L to form droplets only by the pressure due to the deformation of the piezoelectric element 22.

  Examples will be described below.

Using a known photolithography technique (resist coating, exposure, development) and a dry etching method using CF ₄ as a reactive gas on the discharge surface of a nozzle plate made of quartz (thickness: 100 μm) with 32 nozzles having a nozzle diameter of 10 μm. Formed. Further, as the charging electrode 314, a NiP film having a thickness of about 0.5 μm was formed on the inner peripheral surface of the nozzle 310 and the bottom of the pressure chamber by using the RF magnetron sputtering method.

  In addition, the pressure chamber groove, the common flow channel groove, and the flow channel groove connecting the common flow channel groove and the pressure chamber groove in the body plate are formed using a known photolithography technique (resist coating, exposure, Development) and an anisotropic dry etching technique using ICP.

  In the liquid discharge experiment, a conductive liquid containing 3% by mass of a dye (CI Acid Red 1) in ethanol was used.

  The same nozzle plate, body plate, and discharge liquid were used in Examples 1 and 2 and Reference Example 1 below.

The anisotropic dry etching technique has a structure with a high aspect ratio (the ratio between the depth and width of the processed recess, and a high aspect ratio indicates a state where the depth of the groove is deep and the width is narrow). In order to protect the sidewalls of the recesses processed by etching during etching, a cycle for generating chemical species (radicals, ions, etc.) that cause an etching reaction and the sidewalls are protected. This is an etching process in which a cycle for depositing a protective film is alternately performed. By using this anisotropic dry etching technique, the side wall of the recess formed in the silicon substrate can be processed perpendicular to the substrate surface. In this embodiment, SF ₆ was used as an etching gas for forming grooves and holes, and C ₄ F ₈ was used as a deposition gas for the sidewall protective film.

Example 1
An example of the formation of the piezoelectric element on the body plate was performed along the process shown in FIG. A pressure chamber groove 300 made of Si, a flow path groove, and a back surface 301a of the pressure chamber groove 300 of the body plate 301 including a common flow path groove are interposed through a SiO ₂ film 302 having a thickness of about 0.3 μm formed by TEOS processing. Then, a Pt film 303 preferentially oriented to (100) was formed to a thickness of about 0.3 μm in a region where a piezoelectric body was to be formed using a stainless deposition mask (FIG. 3C). As a method of manufacturing the (100) preferential alignment film of the Pt film 303, Japanese Patent Laid-Open No. 6-108242 filed by the present inventors was used. A PZT (lead zirconate titanate) film 304 was formed on the Pt film 303 by RF magnetron sputtering (FIG. 3D). The film forming conditions are shown below.
・ Achieved vacuum: 6.67 × 10 ⁻⁵ Pa
・ Discharge vacuum degree: 6.67 × 10 ⁻¹ Pa
・ Gas: Argon atmosphere of oxygen 20 volume% ・ Substrate temperature: 550 ° C.
・ Target: PbZr _0.48 Ti _0.52 O ₃ (90%) + PbO (10%) mixed ・ Film formation rate: 0.01 μm / min The formation of the piezoelectric film 304 uses an adhesion mask in the same manner as the formation of the Pt film 303 This is dealt with by covering so that the piezoelectric film is not formed in unnecessary areas. When the obtained piezoelectric film 304 was evaluated by X-ray diffraction, it was an epitaxial film preferentially oriented on the C axis of the perovskite structure.

  On the piezoelectric film 304, Cr is deposited on the piezoelectric film 304 by 0.03 μm and Au by 0.3 μm by RF magnetron sputtering using an adhesion mask in the same manner as described above. An independent electrode 305 of the piezoelectric body was formed (FIG. 3E).

Next, Si is removed from the bottom (thickness: 15 μm) of the pressure chamber groove 300 of the body plate 301 by anisotropic etching using ICP (FIG. 3F), and dry etching using the reactive gas CF ₄ is performed. The SiO ₂ film is removed by treatment (FIG. 3G), Pt is removed by Ar plasma treatment (RF power: 500 W, treatment pressure: 6.67 Pa) (FIG. 3H), and the pressure chamber groove 300c is removed. The piezoelectric film 304 was exposed at the bottom. In particular, when removing Si, portions other than the bottom of the pressure chamber groove 300c of the body plate 301 are also etched, so that a flow path groove or the like was formed in consideration of this.

  A nozzle plate 310 is bonded to the body plate 301a with an adhesive (FIG. 3 (i)), and a water-repellent treatment (evaporation of Evaporation maintenance WR1 manufactured by Merck Japan) is performed on the surface of the nozzle plate to provide a liquid-repellent film 316. Thus, the liquid discharge head 320 was completed (FIG. 3 (j)).

  Next, the piezoelectric element electrode 305 and the charging electrode 314 of the liquid discharge head 320 are connected to the electrostatic voltage power supply 18 and the drive voltage power supply 23 including the operation control means 4 shown in FIG. The distance between the surface and the counter electrode was set to 1 mm. Since the discharge liquid is conductive, the liquid in the pressure chamber can function as a common electrode of the piezoelectric element. The drive voltage power supply 23 is connected between the charging electrode 314 and the piezoelectric element electrode 305 in a state where 1.5 kV is applied between the charging electrode 314 and the counter electrode 3 of the liquid discharge head 320 by the electrostatic voltage power supply 18. When a 20 kHz rectangular wave of 40 V was applied and driven, it was confirmed that the liquid was discharged well from each nozzle.

(Example 2)
An example of the formation of the piezoelectric element on the body plate was performed along the process shown in FIG. A region in which a piezoelectric film is formed using a Ti film 403 on a back surface 401a of a pressure chamber groove 400 of a body plate 401 composed of a pressure chamber groove 400, a flow channel groove, and an ink chamber made of Si, using a stainless deposition mask. A film having a thickness of 0.3 μm was formed (FIG. 4B). The Ti film 403 was formed by performing normal DC magnetron sputtering in an Ar atmosphere at a substrate temperature of 250 ° C.

  On top of this, an Al film 402 having a thickness of 2 μm used for lift-off for forming a piezoelectric body is produced by a DC magnetron sputtering method (FIG. 4C), and is formed on the Ti film 403 by a photolithography process and an etching process. The Al film was removed (FIG. 4D).

A sol PZT alcoholate (Inostek: PZT alcoholate for thick film) 404a to be a piezoelectric body is applied on the Ti film 403 and Al film 402 ′ of the body plate 401 by a spin coating method so as to have a thickness of 1 μm. Dry calcination (gelation) was performed at 120 ° C. for 5 minutes (in the air) and at 500 ° C. for 30 minutes (in the air) (FIG. 4E). Next, it was immersed in an Al etching solution (Hanai Chemical Co., Ltd., aluminum etchant solution), and unnecessary PZT was removed together with the Al film (FIG. 4F). This was repeated 10 times to form a PZT film b by stacking to a total thickness of 10 μm, followed by heat treatment at 675 ° C. for 5 hours (oxygen atmosphere: 1.01 × 10 ⁵ Pa). The obtained piezoelectric film 404c was a polycrystalline film of PbZr _0.48 Ti _0.52 O ₃ as evaluated by X-ray diffraction.

  On this piezoelectric film 404c, 0.03 μm of Cr and 0.3 μm of Au were deposited by RF magnetron sputtering through an adhesion mask, and an independent electrode 405 of each piezoelectric body was formed (FIG. 4). (G)).

  Next, a polarization treatment was performed by applying a DC voltage of 70 V between the Ti film 403 and the electrode 405 using a DC voltage source 450 for 1 hour while heating at about 250 ° C. (FIG. 4 ( h)).

  Next, Si is removed from the bottom (thickness: 15 μm) of the pressure chamber groove 400 of the body plate 401 by an anisotropic etching process using ICP (FIG. 4I), and an Ar plasma process (RF power: 500 W) is performed. Pt was removed at a processing pressure of 6.67 Pa (FIG. 4J), and the piezoelectric body 404 was exposed at the bottom of the pressure chamber groove 400c. In particular, when removing Si, portions other than the bottom of the pressure chamber of the body plate are also etched, so that a flow channel and the like were formed in consideration of this.

  A nozzle plate 410 is bonded to the body plate 401 with an adhesive (FIG. 4 (k)), and a liquid repellent film 416 is provided on the surface of the nozzle plate by a water repellent treatment (Merck Japan, Evaporation Substance WR1). A liquid discharge head 420 was completed (FIG. 4L).

  Next, the piezoelectric element electrode 405 and the charging electrode 414 of the ejection head 420 are connected to the electrostatic voltage power source 18 and the drive voltage power source 23 including the operation control means 4 shown in FIG. And the counter electrode were set to have a distance of 1 mm. Since the discharge liquid is conductive, the liquid in the pressure chamber can function as a common electrode of the piezoelectric element. In the state where 1.5 kV is applied between the charging electrode 414 and the counter electrode 3 of the liquid discharge head 420 by the electrostatic voltage power source 18, the driving voltage power source 23 applies 20 kHz between the charging electrode 414 and the electrode 405. When the rectangular wave was driven by applying 40 V, it was confirmed that the liquid was satisfactorily discharged from each nozzle.

(Reference Example 1)
With reference to the Pyrex (registered trademark) glass having a thickness of 20 μm to 100 μm as a vibration plate in Patent Document 1, the bottom portion (thickness: 15 μm) of the pressure chamber groove of the body plate in Example 1 is formed using an ICP. When Si was removed by the isotropic etching process, a liquid ejection head was produced that was exactly the same except that 5 μm was removed because Si having a thickness of 10 μm was used as the diaphragm.

  When this liquid discharge head was subjected to a discharge experiment under the same conditions as in Example 1, an applied voltage of 60 V was required to discharge the liquid in the same state. Further, when the drive application voltage of the liquid discharge head of Example 1 and the liquid discharge head of Reference Example 1 is set to the same 40 V and the frequency of the applied rectangular wave is changed and discharged, the reference example 1 starts from around 15 kHz. As a result, it was confirmed that the amount of liquid droplets discharged from the liquid discharge head was uneven or decreased compared to the amount of liquid droplets discharged from the liquid discharge head of Example 1.

1 is a diagram illustrating an overall configuration of an example of a liquid ejection apparatus having a liquid ejection head that is an example of the present embodiment. It is a figure which expands and shows typically the piezoelectric element peripheral part in FIG. It is a figure which shows typically an example which forms a piezo element in a body plate. It is a figure which shows typically an example which forms a piezo element in a body plate. It is a figure which shows the liquid discharge head for experiment used in order to examine the discharge conditions of a liquid. It is a schematic diagram which shows the electric potential distribution of the discharge hole vicinity of the nozzle by simulation. It is a figure which shows the relationship between the volume resistivity of a nozzle plate, and the electric field strength of a meniscus front-end | tip part. It is a figure which shows the relationship between a nozzle diameter and the electric field strength of a meniscus front-end | tip using the thickness of a nozzle plate as a parameter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid discharge apparatus 2 Liquid discharge head 3 Counter electrode 4 Operation control means 10 Nozzle 11 Nozzle plate 12 Discharge surface 13 Discharge hole 16 Electrode for charging 18 Electrostatic voltage power supply 19 Body plate 20 Pressure chamber 22 Piezo element 23 Drive voltage power supply 28 Repellent Liquid layer 101 SiO2 film 103 Pt film 105 Piezoelectric body 107 Electrode L Liquid D Droplet

Claims (13)

In a liquid discharge head that discharges liquid droplets from a discharge hole of a nozzle communicating with the pressure chamber by transmitting the displacement of the piezoelectric element to the liquid in the pressure chamber.
A nozzle plate formed of a resin or glass having a volume resistivity of 10 ¹⁵ Ω · m or more;
A body plate in which a pressure chamber groove serving as the pressure chamber communicating with the nozzle formed in the nozzle plate is formed of Si or quartz;
The liquid discharge head according to claim 1, wherein the first surface of the piezoelectric element forms a part of a wall of the pressure chamber in contact with the liquid in the pressure chamber. The piezoelectric element has one electrode only on the second surface of the piezoelectric element, and includes at least one of Ti and Zr, Pb, and oxygen. Liquid discharge head. The liquid discharge head according to claim 1, wherein the liquid is conductive. 4. The liquid discharge head according to claim 1, wherein an outermost surface of the nozzle where the discharge hole is present is subjected to a liquid repellent treatment. 5. An electrostatic voltage applying means for generating an electrostatic attraction force by forming an electric field between the liquid in the nozzle and a substrate provided opposite to the surface on which the discharge hole exists; The liquid discharge head according to claim 1, wherein the liquid discharge head is a liquid discharge head. A nozzle that discharges liquid as droplets from the discharge hole, a pressure chamber that discharges from the discharge hole of the nozzle that communicates droplets by pressure change, and pressure generation means that causes a pressure change in the pressure chamber,
A nozzle plate on which the nozzles are formed;
In the method of manufacturing a liquid discharge head, in which the nozzle plate covers and a body plate in which a pressure chamber groove serving as the pressure chamber is formed is joined.
Forming a SiO ₂ film on the opposite surface of the body plate on which the pressure chamber groove is formed;
Forming a first electrode film made of at least one of Pt and Pd preferentially oriented in (100) on the SiO ₂ film;
Forming a piezoelectric film serving as the pressure generating means on the first electrode film using a sputtering method;
Forming a second electrode film on the piezoelectric film;
Removing the member constituting the body plate at the bottom of the pressure chamber groove until reaching the SiO ₂ film;
Removing the SiO ₂ film at the bottom of the pressure chamber groove until reaching the first electrode film;
Removing the first electrode film at the bottom of the pressure chamber groove until reaching the piezoelectric film;
A method for manufacturing a liquid discharge head, comprising: A nozzle that discharges liquid as droplets from a discharge hole, a pressure chamber that discharges from a discharge hole of a nozzle that communicates droplets by pressure change, and pressure generation means that causes a pressure change in the pressure chamber,
A nozzle plate on which the nozzles are formed;
In the method of manufacturing a liquid discharge head, in which the nozzle plate covers and a body plate in which a pressure chamber groove serving as the pressure chamber is formed is joined.
Forming a third electrode film made of at least one of Pt, Ti, Pd, and Zr on a surface of the body plate opposite to a surface on which the pressure chamber groove is formed;
Forming a piezoelectric film serving as the pressure generating means on the third electrode film;
Forming a fourth electrode film on the piezoelectric film;
Performing a polarization treatment of the piezoelectric film by applying a DC voltage between the third electrode film and the fourth electrode film while heating the piezoelectric film;
Removing the member forming the body plate at the bottom of the pressure chamber groove until reaching the third electrode film;
Removing the third electrode film at the bottom of the pressure chamber groove until reaching the piezoelectric film;
A method for manufacturing a liquid discharge head, comprising: 8. The method of manufacturing a liquid discharge head according to claim 6, wherein the body plate is made of Si or quartz. The method of manufacturing a liquid discharge head according to claim 6, wherein the nozzle plate is made of a resin or glass having a volume resistivity of 10 ¹⁵ Ω · m or more. 10. The method of manufacturing a liquid ejection head according to claim 6, wherein the piezoelectric film is formed of a material containing at least one of Ti and Zr, Pb, and oxygen. . The method for manufacturing a liquid discharge head according to claim 6, further comprising a step of performing a liquid repellent treatment on an outermost surface where the discharge hole of the nozzle is present. A liquid discharge head manufactured by the method for manufacturing a liquid discharge head according to claim 6. An electrostatic voltage applying means for generating an electrostatic attraction force by forming an electric field between the liquid in the nozzle and a substrate provided opposite to the surface on which the discharge hole exists; The liquid discharge head according to claim 12.

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