JP2008087444A - Manufacturing method for liquid droplet jet apparatus, and liquid droplet jet apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a liquid droplet jet apparatus which can carry out high-density recording by precisely controlling a nozzle piezoelectric element gap and more improving the stability of printing, and which is employed in ink jetting or the like that uses a hot melt ink, and to provide the liquid droplet jet apparatus. <P>SOLUTION: The manufacturing method for the liquid droplet jet apparatus which has both a nozzle forming member 1 with a plurality of nozzle openings 10, and a plurality of piezoelectric elements set in the ink and opposed to each of the nozzle openings 10 with the nozzle piezoelectric element gap 14 of a predetermined interval kept to the nozzle forming member 1 includes at least the process of forming the nozzle openings 10 in the nozzle forming member 1, the process of forming a sacrifice layer 3 on the nozzle forming member 1, the process of forming piezoelectric elements formed on the sacrifice layer 3 with fixing ends 12 joined onto the nozzle forming member 1, and the process of forming the nozzle piezoelectric element gap 14 by etching the sacrifice layer 3 away. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a manufacturing method of a droplet ejecting apparatus used for an ink jet printer head and the like, and a droplet ejecting apparatus. In particular, the present invention relates to a method for manufacturing a droplet ejecting apparatus that discharges hot melt ink using a piezoelectric element, and a droplet ejecting apparatus.

  In recent years, inkjet printers have become widespread as printers that perform high-quality printing. Such an ink jet printer is expected to have an extremely wide range of applications such as printing, industrial chemicals, and application of pattern materials as well as printing applications. Ink jet printers are typically classified into a piezoelectric type using a piezoelectric element and a thermal type using heating by a heater, both of which are being developed for higher performance.

  An apparatus using hot melt ink is known as an example of a piezoelectric ink jet printer. A hot melt ink is an ink that is a solid or high-viscosity liquid at room temperature and becomes a low-viscosity liquid at a predetermined temperature higher than normal temperature. As an example of such an apparatus, there is an apparatus disclosed in Japanese Patent Publication No. 2692121, and FIG. 11 shows an apparatus configuration. 11, 201 is a nozzle forming member, 204 is a first electrode layer, 205 is a piezoelectric layer, 206 is a second electrode layer, 210 is a nozzle opening, 211 is a piezoelectric element, 212 is a fixed end, 213 is a free end, 214 is a nozzle piezoelectric element gap, 220 is ink, 221 is an ink tank, 222 is an ink supply section, 223 is an ink introduction guide, 224 is an ink introduction path, 225 is a housing, 226 is a filter, and 227 is an ink heating mechanism (posistor). ) 228 and 229 are atmospheric communication portions, 230 is an open end, 231 is a wiring, 232 is an ink droplet, and 233 is a spacer. As shown in the figure, heating means for heating and melting hot melt ink to a predetermined temperature, a nozzle forming member having a plurality of nozzle openings, and each nozzle opening facing each of the nozzle openings with a predetermined interval. It has a plurality of electromechanical conversion means (piezoelectric elements) provided in the ink. According to the above-mentioned conventional apparatus, high-quality printing can be performed on plain paper, and the discharge of bubbles generated due to volume shrinkage when the ink is solidified at room temperature, which is a problem of hot melt ink, is stable. The ink can be ejected stably and can be used preferably in a recording apparatus.

In addition, as an example of an apparatus using such hot melt ink, other ink flow (pressure chamber) provided for each nozzle as disclosed in Japanese Patent Application Laid-Open No. 2000-071452 or Japanese Patent Application Laid-Open No. 2000-127380. In other words, a device has been proposed in which pressure is applied from a piezoelectric element via a vibration plate and droplets are ejected from a nozzle.
Japanese Patent Registration No. 2692121 JP 2000-071452 A JP 2000-127380 A

  In the conventional ink jet recording apparatus, it is necessary to precisely control the interval between the nozzle and the piezoelectric element (hereinafter referred to as nozzle piezoelectric element gap) in order to ensure printing stability. In the prior art, the nozzle piezoelectric element gap is controlled by a spacer made of a thin metal plate provided between the fixed end of the piezoelectric element and the nozzle forming member.

  However, according to the configuration of the conventional example, in order to precisely control the nozzle piezoelectric element gap, it is necessary to control the spacer thickness, thickness unevenness, and deformation very precisely. In addition, high accuracy is required in the joining process of the spacer, the piezoelectric element, the nozzle forming member, and the frame. Further, the gap is controlled only on the fixed end side, and the error generated on the fixed end side is enlarged on the free end side where the nozzle piezoelectric element gap is formed. For the above reasons, it has been difficult to stably control and manufacture the nozzle piezoelectric element gap. For this reason, it is difficult to perform ejection with uniform characteristics from a plurality of nozzles, and it has been difficult to provide a recording apparatus that ensures printing stability.

  In particular, in recent years, recording apparatuses have been required to have higher density due to the demand for high-definition recording, and piezoelectric elements have also been required to be finer and thinner with higher integration. At the same time, the nozzle aperture is also required to be miniaturized, and the nozzle length is shortened in response to the miniaturization (high definition) of the nozzle aperture. Therefore, it is necessary to use a very thin nozzle forming member. In addition, with the miniaturization of piezoelectric elements, high precision is required for alignment with nozzle apertures, but such thin film piezoelectric elements and thin nozzle forming members are fragile and difficult to handle, and both are highly aligned via spacers. Difficulty is involved in processing such as bonding with accuracy. Therefore, application to the above conventional example is difficult, and it is difficult to cope with high density.

  In addition, the apparatus disclosed in Japanese Patent Laid-Open No. 2000-071452 or Japanese Patent Laid-Open No. 2000-127380 has a pressure chamber separated by a partition for each nozzle. In such a configuration, the integration density of the nozzles is limited by the width of the partition walls, so there is a limit to the high density.

  The present invention has been made in view of the above-described problems of the prior art, and its purpose is to precisely control the nozzle piezoelectric element gap to improve printing stability and perform high density recording. An object is to provide a method for manufacturing an ejection device and a droplet ejection device.

  The present invention includes a nozzle forming member having a plurality of nozzle openings and a plurality of piezoelectric elements provided in the ink so as to face each of the nozzle openings, and the nozzle forming member and the piezoelectric elements are predetermined. A method of manufacturing a droplet ejecting apparatus having a configuration in which nozzle piezoelectric element gaps are arranged at intervals, and at least a step of forming nozzle holes in a nozzle forming member, and etching removal in a subsequent step on the nozzle forming member A step of forming a sacrificial layer for forming a nozzle piezoelectric element gap, a step of forming a piezoelectric element formed on the sacrificial layer and having a fixed end bonded to the nozzle forming member, and etching the sacrificial layer. A method for manufacturing a droplet ejecting apparatus, comprising a step of forming a nozzle piezoelectric element gap.

  As the nozzle forming member of the present invention, any material can be used as long as it has sufficient resistance to the ink to be used and can perform processing such as forming a desired nozzle opening. First, a semiconductor material is preferably used as the nozzle forming member of the present invention. Since semiconductor materials are used in large-scale integrated circuits and the like, highly fine processing technology has been established, and processing required for the present invention can be easily performed. Among semiconductor materials, a silicon single crystal is particularly preferable. A silicon single crystal can be easily formed with a nozzle whose shape is controlled with high accuracy by appropriately selecting the crystal plane, etching conditions, and mask opening shape by anisotropic etching. An SOI substrate is also suitable. A conductive material is secondly used as the nozzle forming member of the present invention. The conductive material is formed by bonding the fixed end on the nozzle forming member, so that the potential of the nozzle forming member and the electrode of the piezoelectric element can be made equal. Therefore, it is possible to manufacture the droplet ejecting apparatus with higher yield. The sacrificial layer can be formed easily by a method such as plating or electrodeposition in the sacrificial layer forming step described later. Among the conductive materials, metal materials are particularly preferable. As the metal, stainless steel, nickel, chromium, and the like can be used with almost no limitation. These metal materials can easily produce a thin nozzle forming member by rolling or polishing, and can easily form fine nozzle openings by electric discharge machining or the like. Further, as an example of the nozzle forming member of the present invention, a third example is an insulating material. Since the insulating material has a low thermal conductivity and high heat retention, there is an advantage that the temperature of the melted hot melt ink is reduced due to heat radiation at a location where it is in contact with the air, such as around the nozzle, and stable ejection is possible. A preferable insulating material is a photosensitive resin, and nozzle openings can be easily formed by pattern irradiation such as ultraviolet rays. Another preferable insulating material is a glass material.

  In the present invention, it is necessary to use a nozzle forming member having a thickness corresponding to the nozzle length, and the nozzle length is shortened corresponding to the finer (higher definition) of the nozzle opening, so that it is extremely thin. It is necessary to use something. Therefore, the thickness of the nozzle forming member is preferably 1 μm to 50 μm. In the present invention, when processing such a sacrificial layer and a piezoelectric element, and formation of a nozzle hole is performed on such a thin nozzle forming member, the processing is performed after reinforcement as necessary. As a reinforcing method, there is a method of joining a reinforcing material. As the reinforcing material, a part of a casing (hereinafter referred to as a casing member) constituting an ink-jet ink tank or the like is used in a later process, which is later reinforced. There is no need to separate the materials, which is preferable. As a still more preferable form, a part of the nozzle forming member having a thickness that is easy to handle is processed by etching or cutting to form a recess to form a membrane, and a sacrificial layer and a sacrificial layer are formed on the membrane thus formed. Examples of the method include forming a piezoelectric element and forming a nozzle hole. By doing so, it becomes a configuration that does not have a joint portion as compared with the case where a reinforcing material is separately joined to a thin plate of the nozzle forming member, and in particular, a temperature shock in forming a piezoelectric element that requires a high temperature process. Alternatively, it is possible to prevent peeling of the junction due to the intrusion of an etching solution in a chemical process such as sacrificial layer etching, and to provide a manufacturing method with higher yield. In the present invention, the sacrificial layer and the piezoelectric element may be formed on any surface of the membrane formed on the nozzle forming member, but preferably the sacrificial layer and the piezoelectric element are formed inside the concave portion on the membrane, It is suitable for high-definition recording because the distance between the nozzle opening and the recording paper can be shortened by adopting a configuration in which droplets are discharged from the nozzle opening from the side opposite to the concave portion of the membrane. . When forming an element or the like on the bottom of the recess, processing is performed using a photoresist that can form a mask with a high aspect ratio, for example, SU-8 (MicroChem Corporation). In such a manufacturing method, it is also preferable to use an SOI substrate as the nozzle forming member. It can be produced by controlling the membrane thickness more accurately by using the oxide layer inside the substrate as an etching stop.

  In the step of forming the nozzle hole in the nozzle forming member of the present invention, any machining method such as mechanical cutting, electric discharge machining, etching, or molding using a mold is used. In the present invention, the step of forming the nozzle holes may be performed at any stage of the steps described in claim 1. For example, a method of forming a hole by forming a sacrificial layer on the surface of the nozzle forming member and then aligning from the back surface can be used. In the present invention, since it is necessary to accurately position and form the piezoelectric element with respect to the nozzle opening, a method of performing alignment on the same surface of the nozzle forming member is more preferably used. In the present invention, for example, the following steps may be mentioned.

  (1) A mask layer is formed on the nozzle forming member.

  (2) A fine mask opening is formed in the mask layer.

  (3) The nozzle forming member is etched from the mask opening to form an etching hole.

  Through the steps (1) to (3), the nozzle hole may be formed by penetrating the etching hole to the back surface of the nozzle forming member. Alternatively, by the steps (1) to (3), an etching hole is formed at a depth up to the middle of the thickness of the nozzle forming member, and the nozzle forming member is later polished from the back surface to form nozzle openings as necessary. May be. In the step of etching the nozzle forming member from the mask opening in (3), an approximately semispherical etching hole can be formed using isotropic etching, but the hole shape is controlled using anisotropic etching. It can also be formed. The process when anisotropic etching is used will be described in more detail by giving an example. As an example, a (100) -oriented Si single crystal wafer is used as a nozzle forming member, silicon nitride is used as a mask layer, the mask opening has a rectangular shape at least capable of entering an etching solution, and a KOH aqueous solution or a TMAH aqueous solution is used as the etching solution. Is used to anisotropically etch the (100) -oriented Si single crystal wafer, which is the nozzle forming member 1, to form an anisotropic etching hole in which one side is larger than the mask opening and is etched into an inverted quadrangular pyramid shape. Is possible. This is because, in anisotropic etching using the above etching solution, the etching rate of the (111) plane is very slow relative to the etching rate of the (110) plane or (100) plane, and therefore normally one side is almost the same as the mask opening. An anisotropic etching hole etched into an equal inverted quadrangular pyramid is formed, but the etching rate of the (111) plane can be increased to some extent by selecting the concentration and temperature of the etching solution (Sensors and Actuators A, 34 (1992) 51), it is possible to form an etching hole having the above shape. In addition, by appropriately selecting the etching time, the size and depth of the anisotropic etching hole can be made arbitrarily arbitrary. According to the above process, the mask layer remains in the form of a membrane having an opening. Therefore, a sacrificial layer can be deposited on the mask layer so as to close the mask opening, and a piezoelectric element can be formed on the sacrificial layer. The sacrificial layer is formed so as to close the mask opening by appropriately selecting the film thickness and the deposition method. Mask opening diameter. Specific examples of the material, film thickness, and deposition method of the sacrificial layer are shown in the examples. According to such a process, it becomes possible to align the nozzle opening and the production of the piezoelectric element on the same surface of the nozzle forming member, so that the nozzle can be formed with accurate alignment.

  Further, in the step of forming the nozzle opening in the nozzle forming member of the present invention, after forming a hole having a depth to the middle with respect to the thickness of the nozzle forming member, the nozzle forming member is polished from the back side of the hole. A nozzle opening may be formed at the bottom of the hole.

In the present invention, the aperture area of the nozzle is preferably 1 × 10 ⁻¹¹ m ^{2 to} 1 × 10 ⁻⁹ m ² . By setting it within the above range, it is possible to form a liquid droplet ejecting apparatus that can stably discharge micro liquid droplets even with a small piezoelectric displacement element.

Moreover, in this invention, it is also preferable to form an air | atmosphere communication part in the said nozzle formation member. In terms of the manufacturing method, such an air communication part is a through-hole of a nozzle forming member similar to the nozzle opening and can be formed simultaneously with the nozzle formation. A droplet ejecting apparatus can be provided at low cost. A preferable position for forming the atmosphere communication portion is a portion facing each piezoelectric element of the nozzle forming member, and preferably on the fixed end side of the piezoelectric element with respect to the nozzle opening. In this way, a meniscus (open end) can be formed in the very vicinity of the atmosphere communication portion, and the meniscus position can be set on the fixed end side of the piezoelectric element with extremely high accuracy. Compared with the case where the ink is provided at a distant position, the state of the ink around the minute piezoelectric element can be controlled with high accuracy, and more stable ejection characteristics can be obtained. Further, it is preferable that the opening area of the air communication portion is larger than the opening area of the nozzle opening and is approximately 5 × 10 ⁻¹¹ m ^{2 to} 5 × 10 ⁻⁷ m ² .

  In addition, the sacrificial layer used in the present invention can be dissolved and removed by etching. At that time, the nozzle forming member, the material constituting the piezoelectric element, or a sufficient etching rate ratio to the protective layer formed thereon If it is obtained, it can be used. Such a sacrificial layer is appropriately patterned, and unnecessary portions such as a portion to be a fixed end of the piezoelectric element described later are removed. As an example of a material preferably used as the sacrificial layer material of the present invention, first, an organic material is cited. The organic material is preferably a photosensitive resin such as a photoresist, and can be easily patterned by pattern irradiation such as ultraviolet rays, and the piezoelectric element is easily etched with an organic solvent such as acetone, which is hardly etched. preferable. Secondly, inorganic materials are preferably used as the sacrificial layer material of the present invention. MgO is mentioned as a preferable inorganic material. In the present invention, since the piezoelectric element is formed on the sacrificial layer, MgO suitable for forming a thin film of a perovskite oxide piezoelectric material having particularly high electromechanical conversion characteristics among various piezoelectric materials described later is particularly preferably used. Since a piezoelectric element having good characteristics can be formed on the layer, a droplet discharge device having stable discharge characteristics can be manufactured. In addition, silicon oxide or polysilicon which is used as a sacrificial layer material in a technical field such as micromechanics and whose manufacturing method and etching technology have been developed is also preferably used. A metal material that can be easily formed by plating or the like is also preferable.

  In the present invention, the thickness of the sacrificial layer is determined as the desired nozzle piezoelectric element gap thickness. For this reason, the method for forming the sacrificial layer is appropriately selected from those having good controllability of the film thickness. Examples of suitable ones include deposition of a sacrificial layer material from the gas phase, such as sputtering, CVD, and vacuum deposition. According to these methods, a sacrificial layer whose thickness is controlled with an error of 1 nm or less is formed. In addition, since the nozzle piezoelectric element gap can be formed with extremely high accuracy, a droplet ejecting apparatus having stable ejection characteristics can be manufactured. Another suitable example is the deposition of a sacrificial layer material from a liquid phase such as electroplating, electroless plating, electrodeposition, electrophoresis, etc. These methods can be selectively grown and can be easily deposited on the necessary portions on the nozzle forming member. Moreover, the sacrificial layer material may be applied, and even a relatively thick layer within the range of the sacrificial layer of the present invention can be easily formed by appropriately selecting the viscosity of the coating solution and the coating method.

  The thickness of the sacrificial layer is preferably 1 μm to 50 μm. By setting it within the above range, it is possible to form a liquid droplet ejecting apparatus that can stably discharge micro liquid droplets even with a small piezoelectric displacement element.

  Subsequently, after forming the piezoelectric element on the sacrificial layer, the mask layer and the sacrificial layer are removed by etching.

  As the piezoelectric element, any material, form, and element configuration can be selected as long as they can be arranged facing the nozzle aperture and can be displaced sufficiently to eject ink.

  The piezoelectric material used for the piezoelectric element is not particularly limited as long as a desired driving characteristic can be obtained. Examples include perovskite materials such as PZT materials, ZnO, and the like. Further, a PZT-based alignment film (Jpn. J. Appl. Phys. Vol. 32 (1993) pp. 4057) formed by changing the composition in the film thickness direction is also preferably used in the present invention. The electrode layer is appropriately selected from materials having high conductivity and capable of withstanding heating in the piezoelectric thin film manufacturing process. Preferred examples include noble metal materials such as Pt, Au, Pd, Ir, Rh, Ru. Moreover, these alloys and laminated films can also be used. The method for forming the electrode layer and the piezoelectric layer is appropriately selected from methods that can be formed by sufficiently covering the step at the end of the sacrificial layer. Preferable examples include a deposition method such as a sol-gel method by coating and baking, and a deposition method from a gas phase such as an MO-CVD method or a sputtering method. In the present invention, the piezoelectric element is formed in a form in which a fixed end is bonded onto a nozzle forming member. In the present invention, the fixed end of the piezoelectric element and the nozzle forming member are preferably joined directly by deposition of a film, but may be laminated and joined via an appropriate joining layer.

  As a configuration of the piezoelectric element, a cantilever type element is preferably used in the present invention. As an element structure, electrodes are provided on both surfaces of a thin plate of piezoelectric material, for example, the electrode thicknesses on both surfaces are made different, or a vibration plate material is separately formed on one surface to cause displacement in the bending direction. The configuration. Such a piezoelectric element can obtain a large displacement of the free end with respect to the fixed end, and can stably eject ink. Such a piezoelectric element is formed by depositing upper and lower electrode layers, a piezoelectric layer, and the like and appropriately patterning them. The thickness of the piezoelectric element is appropriately designed in consideration of a necessary displacement amount and a generated force, but is preferably 1 μm to 50 μm, and can be stably combined with the minute nozzle opening to stably generate a minute liquid. A droplet ejecting apparatus capable of ejecting droplets can be formed.

  After the piezoelectric element is formed as a pattern, the sacrificial layer is removed. The sacrificial layer is removed by immersing the element in an etching solution. When the sacrificial layer is removed, when the piezoelectric element portion and the casing member are attacked by the etching solution used, a portion requiring protection is protected with a protective film such as a photoresist. Note that the protective film is removed after the sacrificial layer removing step. The sacrificial layer is removed by etching with an etchant, and the free end of the piezoelectric element pattern is released from the nozzle forming member except for the fixed end of the piezoelectric element pattern, and the fixed end of the piezoelectric element is fixed to the nozzle forming member. The nozzle has a configuration having a nozzle piezoelectric element gap.

  Further, in the sacrificial layer removal step, it is preferable to perform etching removal of the sacrificial layer by introducing an etching solution from a nozzle opening or an air communication portion. At this time, if necessary, a sealing material is used to protect the piezoelectric element pattern and the like. Compared with the case where etching is performed by immersing the entire element in an etching solution, the time for the etching solution to contact the piezoelectric element can be reduced, and the protective film formed on the piezoelectric element is deteriorated or etched from a pinhole. It is possible to reduce the deterioration and destruction of the piezoelectric element due to the penetration of the liquid, and to manufacture the droplet ejecting apparatus with a higher yield.

  By the method described above, a plurality of piezoelectric elements are formed on a nozzle forming member having nozzle openings so as to face each of the nozzle openings with a predetermined nozzle piezoelectric element gap.

  Further, in the present invention, for the nozzle forming member in which such nozzle openings and piezoelectric elements are formed, a casing constituting an ink tank and an ink supply unit, a heating mechanism for heating ink, and a piezoelectric element A liquid droplet ejecting apparatus is manufactured by bonding a wiring for supplying a driving voltage to the substrate. The droplet ejecting apparatus of the present invention is manufactured by the above process, and has a configuration in which the fixed end of the piezoelectric element is fixed to the nozzle forming member and has a nozzle piezoelectric element gap corresponding to the sacrificial layer thickness. Further, the droplet ejecting apparatus of the present invention is provided with a mechanism for applying individually controlled driving voltages to the piezoelectric elements.

  As described above, according to the present invention, the nozzle piezoelectric element gap is accurately arranged at a desired value, variation thereof is small, and discharge with a uniform characteristic can be performed from a plurality of nozzles, and sufficient printing stability is ensured. The liquid droplet ejecting apparatus can be provided.

  As described above, according to the present invention, it is possible to provide a manufacturing method of a droplet ejecting apparatus and a droplet ejecting apparatus capable of precisely controlling a nozzle piezoelectric element gap to further improve printing stability and perform high density recording. Can do.

  Hereinafter, the present invention will be described in more detail with reference to examples.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a process diagram of a method for producing a nozzle piezoelectric element gap portion of a droplet ejecting apparatus of the present embodiment, and FIG. 2 is a sectional view of the droplet ejecting apparatus of the present embodiment.

  First, the manufacturing method of the nozzle piezoelectric element gap part of the droplet ejecting apparatus of the present embodiment will be described with reference to FIG.

  In FIG. 1, 1 is a nozzle forming member, 2 is a first mask layer, 3 is a sacrificial layer, 4 is a first electrode layer, 5 is a piezoelectric layer, 6 is a second electrode layer, 7 is a housing member, and 8 is a housing member. The second mask layer, 9 is a mask opening, 10 is a nozzle opening, 11 is a piezoelectric element, 12 is a fixed end, 13 is a free end, and 14 is a nozzle piezoelectric element gap.

  First, as shown in FIG. 1A, a first mask layer 2 was formed on a nozzle forming member 1, and a sacrificial layer 3 was further formed on a part thereof. As the nozzle forming member 1, a Si single crystal wafer having a thickness of 300 μm and a (110) plane orientation was used. Further, a 300 nm silicon nitride film was deposited by LP-CVD to form a first mask layer 2 on the surface. Subsequently, a silicon oxide film having a thickness of 10 μm was deposited by high-frequency sputtering, and unnecessary portions were removed by etching to form a sacrificial layer 3.

Subsequently, as shown in FIG. 1B, a first electrode layer 4, a piezoelectric layer 5, and a second electrode layer 6 were sequentially deposited. The first electrode layer 4 was formed by depositing Ti in a thickness of 5 nm and Pt in a thickness of 100 nm by high frequency sputtering. The piezoelectric layer 5 was formed by depositing ZnO with a thickness of 8 μm by high frequency sputtering. The film formation conditions of the piezoelectric layer 5 are ZnO as a target, 10% O ₂ added to Ar as a sputtering gas, a total pressure of 2 Pa, a substrate temperature of 200 ° C., and a high frequency output of 4 W / cm ^{2 with} respect to the target. Applied. The second electrode layer 6 was formed by depositing 500 nm of Pt by high frequency sputtering.

  Subsequently, as shown in FIG. 1C, the first electrode layer 4, the piezoelectric layer 5, and the second electrode layer 6 were patterned by photolithography and etching to form a piezoelectric element pattern. Etching was performed by dry etching using plasma with Ar gas for the first electrode layer 4 and the second electrode layer 6, and wet etching using an acidic aqueous solution for the piezoelectric layer 5. The piezoelectric element pattern was a rectangular cantilever type having a length of 500 μm and a width of 100 μm. In addition, although not shown, the silicon mask was exposed by removing a joint portion of the first mask layer 2 with a casing member described later.

  Subsequently, as shown in FIG. 1 (d), a casing member 7 constituting a part of the casing described later was joined to the nozzle forming member 1. As the casing member 7, Pyrex (registered trademark) glass (registered trademark of Corning, # 7740) processed by cutting or the like was used. For bonding, the silicon exposed surface of the nozzle forming member 1 and the casing member 7 were cleaned and overlapped, heated to 200 ° C., a voltage of 200 V was applied between them, and further pressed to perform anodic bonding.

  Subsequently, as shown in FIG. 1 (e), the nozzle forming member 1 was polished from the back surface of the surface on which the piezoelectric element pattern was formed, and thinned to a thickness of 30 μm. The thinning process was performed by lapping using a lapping machine and an abrasive, and the surface was flattened by removing irregularities and undulations. Further, during polishing, the abrasive particle size was made minute in steps, and finally the polished surface was mirror-finished using colloidal silica.

  Subsequently, as shown in FIG. 1 (f), a second mask layer 8 was formed on the polished surface of the nozzle forming member 1. As the second mask layer 8, a silicon nitride film having a thickness of 300 nm was formed by plasma CVD.

  Subsequently, as shown in FIG. 1G, a mask opening 9 was formed in the second mask layer 8. The mask opening 9 was a square having a side of 25 μm. The mask openings 9 were all formed at positions facing the free end portion of the piezoelectric element portion.

  Subsequently, as shown in FIG. 1 (h), the nozzle forming member 1 is anisotropically etched from the mask opening 9 using a KOH aqueous solution, and the opening portion of the first mask layer 2 is also etched away to open the nozzle. Hole 10 was formed. The (110) -oriented silicon single crystal used as the nozzle forming member 1 in this example is anisotropically etched in a direction substantially perpendicular to the surface so that the cross section is 25 μm × 25 μm and the length is 30 μm. The nozzle opening 10 having the shape shown in the figure was formed.

  Subsequently, as shown in FIG. 1 (i), the sacrificial layer 3 is etched with an aqueous HF solution after protecting the parts requiring protection such as the piezoelectric element portion and the housing member with a protective film made of a photoresist (not shown). The piezoelectric element 11 was formed in a form having a gap of the nozzle piezoelectric element gap 13 by removing from the nozzle forming member 1 up to the free end 13 except for the fixed end 12 of the piezoelectric element pattern. The piezoelectric element 11 was formed with a length from the fixed end to the free end of 500 μm and a width of 100 μm, and the interval between the nozzle piezoelectric element gaps 14 was 10 μm. A plurality of piezoelectric elements 11 were formed so that the interval was 50 μm. The protective film was removed after this step.

  In this example, 200 sets of piezoelectric elements and mask openings were formed in parallel with the above dimensions and intervals.

  With the manufacturing method described above, the nozzle piezoelectric element gap portion of the droplet ejecting apparatus of this example was manufactured.

  When the gap between the nozzle piezoelectric element gaps 13 of the nozzle piezoelectric element gap produced as described above was measured using a laser microscope, all the elements could be formed within ± 0.5 microns with respect to 10 μm.

  According to the manufacturing method of the present embodiment described above, the nozzle piezoelectric element gap was precisely controlled, and it was possible to produce a plurality of elements with extremely small spacing variations.

  FIG. 2 shows a droplet ejecting apparatus using a nozzle piezoelectric element gap portion of the droplet ejecting apparatus manufactured by the manufacturing method of the present embodiment. In FIG. 2, 101 is a nozzle forming member, 104 is a first electrode layer, 105 is a piezoelectric layer, 106 is a second electrode layer, 107 is a housing member, 110 is a nozzle opening, 111 is a piezoelectric element, and 112 is a fixed end. 113 is a free end, 114 is a nozzle piezoelectric element gap, 120 is ink, 121 is an ink tank, 122 is an ink supply unit, 123 is an ink introduction guide 124 is an ink introduction path, 125 is a housing, 126 is a filter, and 127 is Ink heating mechanism, 128 and 129 are air communication portions, 130 is an open end, 131 is a wiring, and 132 is an ink droplet. Further, the droplet ejecting apparatus of the present embodiment is provided with a mechanism for applying individually controlled driving voltages to the piezoelectric elements.

  In the droplet ejecting apparatus of this embodiment, ink droplets are ejected as follows. First, power is supplied to the ink heating mechanism 126 from a power source (not shown) to raise the temperature of the ink supply unit 122 and the ink tank 121 to the ink melting temperature. By doing so, the ink 120 in the ink supply unit 122 was dissolved, passed through the filter 126, and flowed into the ink tank 121. The ink 120 that has flowed up rises in a narrow gap formed between the nozzle forming member 101, the piezoelectric element 111, and the ink introduction guide 124 by capillary action, and near the open end 130 of the ink introduction path. Will be introduced. Further, a drive voltage is individually applied to the piezoelectric element 111 from the wiring 131 to displace the free end 113 of the piezoelectric element in the left-right direction in the figure, thereby applying pressure to the ink 120 in the vicinity of the nozzle piezoelectric element gap and opening the nozzle. The ink droplets were ejected from the holes 110 as ink droplets 132.

  In the liquid droplet ejecting apparatus of this example, it was possible to perform ejection with uniform characteristics from a plurality of nozzles. That is, according to this example, it was possible to provide a liquid droplet ejecting apparatus that ensured sufficient printing stability.

  A second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a process diagram of a manufacturing method of the nozzle piezoelectric element gap portion of the droplet ejecting apparatus of this embodiment, and FIG. 4 is a sectional view of the droplet ejecting apparatus of the present embodiment.

  First, the manufacturing method of the nozzle piezoelectric element gap part of the droplet ejecting apparatus of the present embodiment will be described with reference to FIG.

  In FIG. 3, 1 is a nozzle forming member, 3 is a sacrificial layer, 4 is a first electrode layer, 5 is a piezoelectric layer, 6 is a second electrode layer, 7 is a casing member, 10 is a nozzle opening, and 11 is a piezoelectric element. , 12 is a fixed end, 13 is a free end, and 14 is a nozzle piezoelectric element gap.

  First, as shown in FIG. 3A, a sacrificial layer 3 was partially formed on the nozzle forming member 1. As the nozzle forming member 1, Ti having a thickness of 200 nm was deposited by high frequency sputtering on a mirror-polished SUS304 plate having a thickness of 50 μm. Unnecessary portions were masked with a mask made of an insulator (not shown), and then 10 μm of Au was deposited by electroless plating, and the masking (not shown) was removed to form a sacrificial layer 3. The plating bath was a solution in which sulfite was dissolved as a gold salt and ascorbic acid was dissolved as a reducing agent, and the solution temperature was 60 ° C.

Subsequently, as shown in FIG. 3B, the first electrode layer 4, the piezoelectric layer 5, and the second electrode layer 6 were sequentially deposited. The first electrode layer 4 was formed by depositing Ti in a thickness of 5 nm and Pt in a thickness of 100 nm by high frequency sputtering. The piezoelectric layer 5 was formed by depositing ZnO to a thickness of 10 μm by high frequency sputtering. The film formation conditions of the piezoelectric layer 5 are ZnO as a target, 10% O ₂ added to Ar as a sputtering gas, a total pressure of 2 Pa, a substrate temperature of 200 ° C., and a high frequency output of 4 W / cm ^{2 with} respect to the target. Applied. The second electrode layer 6 was formed by depositing 1 μm of Pt by high frequency sputtering.

  Subsequently, as shown in FIG. 3C, the first electrode layer 4, the piezoelectric layer 5, and the second electrode layer 6 were patterned by photolithography and etching to form a piezoelectric element pattern. Etching was performed by dry etching using plasma with Ar gas for the first electrode layer 4 and the second electrode layer 6, and wet etching using an acidic aqueous solution for the piezoelectric layer 5. The piezoelectric element pattern was a rectangular cantilever type having a length of 700 μm and a width of 150 μm.

  Subsequently, as shown in FIG. 3 (d), a casing member 7 constituting a part of the casing described later was joined to the nozzle forming member 1. As the casing member 7, Pyrex (registered trademark) glass (registered trademark of Corning, # 7740) processed by cutting or the like was used. For the joining, the nozzle forming member 1 and the housing member 7 were cleaned, and an epoxy adhesive was applied, superimposed, heated to 100 ° C. and pressed to adhere.

  Subsequently, as shown in FIG. 3 (e), the nozzle forming member 1 was subjected to electric discharge machining to form a nozzle hole 10 so that the cross section had a circular shape with a diameter of 15 μm and a length of 50 μm.

  Subsequently, as shown in FIG. 3 (f), the parts requiring protection such as the piezoelectric element portion and the housing member are protected by a protective film made of a photoresist (not shown), and then the sacrifice layer 3 is dissolved in KI and iodine. Etching with an aqueous solution was performed, and the piezoelectric element pattern was released from the nozzle forming member 1 except for the fixed end 12 of the piezoelectric element pattern, and the piezoelectric element 11 was formed with a gap between the nozzle piezoelectric element gaps 13. . The piezoelectric element 11 was formed with a length from the fixed end to the free end of 700 μm and a width of 150 μm, and the interval between the nozzle piezoelectric element gaps 14 was 10 μm. A plurality of piezoelectric elements 11 were formed so that the interval was 50 μm. The protective film was removed after this step.

  In this example, 200 sets of piezoelectric elements and mask openings were formed in parallel with the above dimensions and intervals.

  With the manufacturing method described above, the nozzle piezoelectric element gap portion of the droplet ejecting apparatus of this example was manufactured.

  When the gap between the nozzle piezoelectric element gaps 13 of the nozzle piezoelectric element gap produced as described above was measured using a laser microscope, all the elements could be formed within ± 0.5 microns with respect to 10 μm.

  According to the manufacturing method of the present embodiment described above, the nozzle piezoelectric element gap was precisely controlled, and it was possible to produce a plurality of elements with extremely small spacing variations.

  Further, in this embodiment, by using a conductive material as the nozzle forming member, the piezoelectric element is formed by bonding a fixed end on the nozzle forming member, so that the potential of the nozzle forming member and the electrode of the piezoelectric element is increased. Since the potential could be kept constant, no sticking due to electrostatic force was observed in the manufacturing process, and the droplet ejection device could be manufactured with a higher yield.

  FIG. 4 shows a droplet ejecting apparatus using the nozzle piezoelectric element gap portion of the droplet ejecting apparatus manufactured by the manufacturing method of the present embodiment. In this embodiment, the configuration of the droplet ejecting apparatus excluding the nozzle piezoelectric element gap is the same as that of the first embodiment.

  In the liquid droplet ejecting apparatus of the present example as well as Example 1, it was possible to perform ejection with uniform characteristics from a plurality of nozzles. That is, according to this example, it was possible to provide a liquid droplet ejecting apparatus that ensured sufficient printing stability.

  A third embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a process diagram of a manufacturing method of the nozzle piezoelectric element gap portion of the droplet ejecting apparatus of this embodiment, and FIG. 4 is a sectional view of the droplet ejecting apparatus of the present embodiment.

  First, the manufacturing method of the nozzle piezoelectric element gap part of the droplet ejecting apparatus of the present embodiment will be described with reference to FIG.

  In FIG. 3, 1 is a nozzle forming member, 3 is a sacrificial layer, 4 is a first electrode layer, 5 is a piezoelectric layer, 6 is a second electrode layer, 7 is a casing member, 10 is a nozzle opening, and 11 is a piezoelectric element. , 12 is a fixed end, 13 is a free end, and 14 is a nozzle piezoelectric element gap.

  First, as shown in FIG. 3A, a sacrificial layer 3 was partially formed on the nozzle forming member 1. As the nozzle forming member 1, Ti having a thickness of 200 nm was deposited by high frequency sputtering on a mirror-polished SUS304 plate having a thickness of 50 μm. The sacrificial layer 3 was formed by applying a photosensitive resin to a thickness of 10 μm and then processing by ultraviolet pattern irradiation and development to remove unnecessary portions to form the sacrificial layer 3.

Subsequently, as shown in FIG. 3B, the first electrode layer 4, the piezoelectric layer 5, and the second electrode layer 6 were sequentially deposited. The first electrode layer 4 was formed by depositing Ti in a thickness of 5 nm and Pt in a thickness of 100 nm by high frequency sputtering. The piezoelectric layer 5 was deposited with 10 μm of AlN by cluster ion beam evaporation. The piezoelectric layer 5 was formed at a substrate temperature of 150 ° C. in a nitrogen gas atmosphere using Al as an evaporation source and added with O ₃ . The second electrode layer 6 was formed by depositing 1 μm of Pt by high frequency sputtering.

  Subsequently, as shown in FIG. 3C, the first electrode layer 4, the piezoelectric layer 5, and the second electrode layer 6 were patterned by photolithography and etching to form a piezoelectric element pattern. Etching was performed by dry etching using plasma with Ar gas for the first electrode layer 4 and the second electrode layer 6, and wet etching using an acidic aqueous solution for the piezoelectric layer 5. The piezoelectric element pattern was a rectangular cantilever type having a length of 700 μm and a width of 150 μm.

  Subsequently, as shown in FIG. 3 (d), a casing member 7 constituting a part of the casing described later was joined to the nozzle forming member 1. As the casing member 7, Pyrex (registered trademark) glass (registered trademark of Corning, # 7740) processed by cutting or the like was used. For the joining, the nozzle forming member 1 and the housing member 7 were cleaned, and an epoxy adhesive was applied, superimposed, heated to 100 ° C. and pressed to adhere.

  Subsequently, as shown in FIG. 3 (e), the nozzle forming member 1 was subjected to electric discharge machining to form a nozzle hole 10 so that the cross section had a circular shape with a diameter of 15 μm and a length of 50 μm.

  Subsequently, as shown in FIG. 3F, the sacrificial layer 3 is removed by etching with an organic solvent, and the piezoelectric element pattern is released from the nozzle forming member 1 to the free end 13 except for the fixed end 12 of the piezoelectric element pattern. Was formed in a form having a gap of the nozzle piezoelectric element gap 13. The piezoelectric element 11 was formed with a length from the fixed end to the free end of 700 μm and a width of 150 μm, and the interval between the nozzle piezoelectric element gaps 14 was 10 μm. A plurality of piezoelectric elements 11 were formed so that the interval was 50 μm.

  In this example, 200 sets of piezoelectric elements and mask openings were formed in parallel with the above dimensions and intervals.

  With the manufacturing method described above, the nozzle piezoelectric element gap portion of the droplet ejecting apparatus of this example was manufactured.

  When the gap between the nozzle piezoelectric element gaps 13 of the nozzle piezoelectric element gap produced as described above was measured using a laser microscope, all the elements could be formed within ± 0.5 microns with respect to 10 μm.

  According to the manufacturing method of the present embodiment described above, the nozzle piezoelectric element gap was precisely controlled, and it was possible to produce a plurality of elements with extremely small spacing variations.

  Further, in this embodiment, by using a conductive material as the nozzle forming member, the piezoelectric element is formed by bonding a fixed end on the nozzle forming member, so that the potential of the nozzle forming member and the electrode of the piezoelectric element is increased. Since the potential could be kept constant, no sticking due to electrostatic force was observed in the manufacturing process, and the droplet ejection device could be manufactured with a higher yield.

  FIG. 4 shows a droplet ejecting apparatus using the nozzle piezoelectric element gap portion of the droplet ejecting apparatus manufactured by the manufacturing method of the present embodiment. In this embodiment, the configuration of the droplet ejecting apparatus excluding the nozzle piezoelectric element gap is the same as that of the first embodiment.

  In the liquid droplet ejecting apparatus of the present example as well as Example 1, it was possible to perform ejection with uniform characteristics from a plurality of nozzles. That is, according to this example, it was possible to provide a liquid droplet ejecting apparatus that ensured sufficient printing stability.

  A fourth embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a process diagram of a method for producing a nozzle piezoelectric element gap portion of the droplet ejecting apparatus of this embodiment, and FIG. 6 is a sectional view of the droplet ejecting apparatus of this embodiment.

  First, the manufacturing method of the nozzle piezoelectric element gap part of the droplet ejecting apparatus of the present embodiment will be described with reference to FIG. In FIG. 5, 1 is a nozzle forming member, 2 is a first mask layer, 3 is a sacrificial layer, 4 is a first electrode layer, 5 is a piezoelectric layer, 6 is a second electrode layer, 7 is a housing member, and 9 is a housing member. Mask openings, 10 are nozzle openings, 11 are piezoelectric elements, 12 are fixed ends, 13 are free ends, 14 are nozzle piezoelectric element gaps, 15 are anisotropic etching holes, and 16 is a sacrificial layer material.

  First, as shown in FIG. 5A, the first mask layer 2 was formed on the nozzle forming member 1. As the nozzle forming member 1, a Si single crystal wafer having a thickness of 300 μm and a (100) plane orientation was used. Further, a 300 nm silicon nitride film was deposited by LP-CVD to form a first mask layer 2 on the surface.

  Subsequently, as shown in FIG. 5B, a mask opening 9 was formed in the first mask layer 2. The mask opening was a rectangle with a side of 3 μm.

  Subsequently, as shown in FIG. 5C, the nozzle forming member 1 was anisotropically etched from the mask opening 9 using an aqueous TMAH solution as an etching solution to form an anisotropic etching hole 15. In this step, the etchant that has entered through the mask opening 9 anisotropically etches the (100) plane Si single crystal wafer, which is the nozzle forming member 1, and is etched into an inverted square pyramid as shown in the figure. An isotropic etching hole 15 was formed. In this step, the first mask layer 2 is left in the form of a membrane having an opening. The etching time was selected so that the anisotropic etching hole 15 was formed to have a side of 30 μm and a depth of about 20 μm. In the anisotropic etching of this example, the TMAH concentration is 10 wt. %, And the liquid temperature was 60 ° C.

Subsequently, as shown in FIG. 5D, a sacrificial layer 3 was formed on a part of the nozzle forming member 1. In this example, as the sacrificial layer, 7 μm of MgO was deposited by high frequency sputtering, and unnecessary portions were removed by etching to form the sacrificial layer 3. In the film formation, a target obtained by firing MgO is used, and a gas in which Ar and O ₂ are mixed in a ratio of 5: 2 is applied so that the high frequency power is 2.0 W / cm ² with respect to the target. The temperature was 250 ° C. In this embodiment, when the sacrificial layer is formed, the substrate is rotated and the substrate is disposed at a position where the sputtered particles are incident from an oblique direction from the target, and a thin film is deposited in a direction covering the opening of the mask opening 9. Then, the opening was formed to have a substantially flat surface together with the block. At this time, a small amount of the sacrificial layer material 16 entered from the mask opening 9 and deposited in the anisotropic etching hole 15.

Subsequently, as shown in FIG. 5E, the first electrode layer 4, the piezoelectric layer 5, and the second electrode layer 6 were sequentially deposited. The first electrode layer 4 was formed by depositing Ti in a thickness of 5 nm and Pt in a thickness of 100 nm by high frequency sputtering. The piezoelectric layer 5 was formed by depositing ₃ μm of Pb (Zr _x Ti _(1-x) ) O ₃ . The conditions for forming the piezoelectric layer 5 are as follows: a target obtained by mixing and firing Pb _1.1 Zr _0.5 Ti _0.5 O _{x in} a ratio of 5: 1 Ar and O ₂ , The high frequency power was applied to 1.5 W / cm ² and the substrate temperature was 620 ° C. The second electrode layer 6 was formed by depositing 500 nm of Pt by high frequency sputtering.

  Subsequently, as shown in FIG. 5 (f), the first electrode layer 4, the piezoelectric layer 5, and the second electrode layer 6 were patterned by photolithography and etching to form a piezoelectric element pattern. Etching was performed by dry etching using plasma with Ar gas for the first electrode layer 4 and the second electrode layer 6, and wet etching using an acidic aqueous solution for the piezoelectric layer 5. The piezoelectric element pattern was a rectangular cantilever type having a length of 200 μm and a width of 50 μm. In addition, although not shown, the silicon mask was exposed by removing a joint portion of the first mask layer 2 with a casing member described later.

  Subsequently, as shown in FIG. 5G, a case member 7 constituting a part of the case described later was joined to the nozzle forming member 1. As the casing member 7, Pyrex (registered trademark) glass (registered trademark of Corning, # 7740) processed by cutting or the like was used. For bonding, the silicon exposed surface of the nozzle forming member 1 and the casing member 7 were cleaned and overlapped, heated to 200 ° C., a voltage of 200 V was applied between them, and further pressed to perform anodic bonding.

  Subsequently, as shown in FIG. 5 (h), the nozzle forming member 1 was polished from the back surface of the surface on which the piezoelectric element pattern was formed, and thinned to a thickness of 15 μm. The thinning process was performed by lapping using a lapping machine and an abrasive, and the surface was flattened by removing irregularities and undulations. Further, during polishing, the abrasive particle size was made minute in steps, and finally the polished surface was mirror-finished using colloidal silica. In addition, an opening was formed in the back surface of the nozzle forming member 1 by this polishing process, and the nozzle hole 10 was formed. The diameter of the nozzle hole 10 was 10 μm.

  Subsequently, as shown in FIG. 5 (i), the parts requiring protection such as the piezoelectric element portion and the housing member are protected by a protective film made of a photoresist (not shown), and then the first aqueous solution is used with a phosphoric acid aqueous solution. The mask layer 2 and the sacrificial layer 3 made of MgO are removed by etching, and the piezoelectric element 11 is released from the nozzle forming member 1 to the free end 13 except for the fixed end 12 of the piezoelectric element pattern. It was formed in the form with The piezoelectric element 11 was formed with a length from the fixed end to the free end of 200 μm and a width of 50 μm, and the interval between the nozzle piezoelectric element gaps 13 was 7 μm. A plurality of piezoelectric elements 12 were formed so that the interval was 30 μm. The protective film was removed after this step. In addition, the sacrificial layer material 16 deposited in the anisotropic etching hole 15 in the step of FIG. 5D is etched away together with the sacrificial layer 3 and the first mask layer 2 in this step.

  In this example, 200 sets of piezoelectric elements and mask openings were formed in parallel with the above dimensions and intervals.

  With the manufacturing method described above, the nozzle piezoelectric element gap portion of the droplet ejecting apparatus of this example was manufactured.

  When the gap between the nozzle piezoelectric element gaps 13 of the nozzle piezoelectric element gap produced as described above was measured using a laser microscope, all the elements could be formed within ± 0.5 microns with respect to 7 μm.

  According to the manufacturing method of the present embodiment described above, the nozzle piezoelectric element gap was precisely controlled, and it was possible to produce a plurality of elements with extremely small spacing variations.

  Furthermore, according to the manufacturing method of the droplet ejecting apparatus of the present embodiment, it is possible to align the nozzle hole and the piezoelectric element on the same surface of the nozzle forming member, and form the nozzle hole with high accuracy. I was able to. For this reason, in comparison with Example 1, although the piezoelectric element and the nozzle aperture were made minute, no element defect or characteristic variation due to misalignment was observed, and the device could be manufactured satisfactorily. did it.

  FIG. 6 shows a droplet ejecting apparatus using the nozzle piezoelectric element gap portion of the droplet ejecting apparatus manufactured by the manufacturing method of this example. In this embodiment, the configuration of the droplet ejecting apparatus excluding the nozzle piezoelectric element gap is the same as that of the first embodiment.

  In the liquid droplet ejecting apparatus of this example, it was possible to perform ejection with uniform characteristics from a plurality of nozzles. That is, according to this example, it was possible to provide a liquid droplet ejecting apparatus that ensured sufficient printing stability.

  A fifth embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a process diagram of a method for producing the nozzle piezoelectric element gap portion of the droplet ejecting apparatus of the present embodiment, and FIG. 8 is a sectional view of the droplet ejecting apparatus of the present embodiment.

  First, the manufacturing method of the nozzle piezoelectric element gap part of the droplet ejecting apparatus of the present embodiment will be described with reference to FIG. In FIG. 7, 1 is a nozzle forming member, 2 is a first mask layer, 3 is a sacrificial layer, 4 is a first electrode layer, 5 is a piezoelectric layer, 6 is a second electrode layer, 9 is a mask opening, and 10 is a nozzle. An aperture, 11 is a piezoelectric element, 12 is a fixed end, 13 is a free end, 14 is a nozzle piezoelectric element gap, 15 is an anisotropic etching hole, 16 is a sacrificial layer material, 17 is a recess, and 18 is a membrane.

  First, as shown in FIG. 7A, a (100) plane Si single crystal wafer on which a thermal oxide film (not shown) is deposited as a nozzle forming member 1 is used as a nozzle forming member 1 and processed by ordinary anisotropic etching. Thus, a recess 17 was formed in a part. Etching conditions were controlled so that the recess 17 had a depth of 150 μm, and a membrane 18 made of Si having a thickness of 20 μm was formed at the bottom.

  Subsequently, as shown in FIG. 7B, a silicon nitride film was further deposited by 300 nm by LP-CVD to form the first mask layer 2 on the entire surface including the concave portion 17 of the nozzle forming member 1.

  Subsequently, as shown in FIG. 7C, a mask opening 9 was formed in the first mask layer 2. The mask opening 9 was formed using a FIB (focused ion beam) etching apparatus, and the mask opening was a rectangle having a side of 3 μm.

  Subsequently, as shown in FIG. 7D, the nozzle forming member 1 was anisotropically etched from the mask opening 9 to form anisotropic etching holes. Although this step was performed in the same manner as in Example 2, by controlling the etching time, an anisotropic etching hole was penetrated to the back surface of the nozzle forming member to form an opening on the back surface, and the nozzle hole 10 was formed. . The diameter of the nozzle hole 10 was 10 μm. In this step, anisotropic etching was performed in a state where the silicon exposed portion of the nozzle forming member was protected by a protective film (not shown), and the protective film was removed after completion.

  Subsequently, as shown in FIG. 7 (e), a sacrificial layer 3 was formed on a part of the inside of the concave portion on the membrane of the nozzle forming member 1. As the sacrificial layer, 7 μm of MgO was deposited by high frequency sputtering, and unnecessary portions were removed by etching to form the sacrificial layer 3. During film formation, the substrate is rotated in the same manner as in Example 3, and the substrate is disposed at a position where the sputtered particles are incident from the target in an oblique direction, and a thin film is deposited in a direction to close the opening of the mask opening 9. The opening was formed so as to have a substantially flat surface together with the block. At this time, a small amount of the sacrificial layer material 16 entered from the mask opening 9 and deposited in the nozzle opening 10. Unnecessary portions are removed by a combination of photolithography and etching. In this embodiment, since the bottom portion of the recess 17 is processed, SU-8 (Micro Chem Corporation) is used as a photoresist as a mask. Etching was performed by forming a resist pattern having a large ratio. Hereinafter, the photolithography process related to the processing of the bottom of the recess 17 in this example was performed in the same manner.

Subsequently, as shown in FIG. 7F, the first electrode layer 4, the piezoelectric layer 5, and the second electrode layer 6 were sequentially deposited. The first electrode layer 4 was formed by depositing Ti in a thickness of 5 nm and Pt in a thickness of 100 nm by high frequency sputtering. The piezoelectric layer 5 was formed by depositing ₃ μm of Pb (Zr _x Ti _(1-x) ) O ₃ . The conditions for forming the piezoelectric layer 5 are as follows: a target obtained by mixing and firing Pb _1.1 Zr _0.5 Ti _0.5 O _{x in} a ratio of 5: 1 Ar and O ₂ , The high frequency power was applied to 1.5 W / cm ² and the substrate temperature was 620 ° C. The second electrode layer 6 was formed by depositing 500 nm of Pt by high frequency sputtering.

  Subsequently, as shown in FIG. 7G, the first electrode layer 4, the piezoelectric layer 5, and the second electrode layer 6 were patterned by photolithography and etching to form a piezoelectric element pattern. Etching was performed by dry etching using plasma with Ar gas for the first electrode layer 4 and the second electrode layer 6, and wet etching using an acidic aqueous solution for the piezoelectric layer 5. The piezoelectric element pattern was a rectangular cantilever type having a length of 200 μm and a width of 50 μm.

  Subsequently, as shown in FIG. 7 (h), a portion requiring protection such as the piezoelectric element portion is protected by a protective film made of a photoresist (not shown), and then the first mask layer is formed using a phosphoric acid aqueous solution as an etching solution. The sacrificial layer 3 made of 2 and MgO is removed by etching, and the free end 13 is released from the nozzle forming member 1 except for the fixed end 12 of the piezoelectric element pattern so that the piezoelectric element 11 has a gap of the nozzle piezoelectric element gap 14. Formed in the shape. In the present embodiment, this step is performed by etching the recess 17 formed in the nozzle forming member 1 with a sealing material (not shown) to protect the piezoelectric element pattern and the sacrificial layer from the nozzle opening. The sacrificial layer was removed by etching. The piezoelectric element 11 was formed with a length from the fixed end to the free end of 200 μm and a width of 50 μm, and the interval between the nozzle piezoelectric element gaps 13 was 7 μm. A plurality of piezoelectric elements 12 were formed so that the interval was 30 μm. The protective film was removed after this step. In addition, the sacrificial layer material 16 deposited in the anisotropic etching hole 15 in the step of FIG. 7D was removed by etching together with the sacrificial layer 3 and the first mask layer 2 in this step.

  In this example, 200 sets of piezoelectric elements and mask openings were formed in parallel with the above dimensions and intervals.

  With the manufacturing method described above, the nozzle piezoelectric element gap portion of the droplet ejecting apparatus of this example was manufactured.

  When the gap between the nozzle piezoelectric element gaps 13 of the nozzle piezoelectric element gap produced as described above was measured using a laser microscope, all the elements could be formed within ± 0.5 microns with respect to 7 μm.

  According to the manufacturing method of the present embodiment described above, the nozzle piezoelectric element gap was precisely controlled, and it was possible to produce a plurality of elements with extremely small spacing variations.

  Furthermore, it becomes a structure which does not have a joining location compared with the case where a reinforcing material is joined separately with respect to the thin plate of the nozzle forming member shown in Example 1 to Example 3, and avoids problems such as peeling of the joining location. Thus, a manufacturing method with a higher yield could be provided.

  FIG. 8 shows a droplet ejecting apparatus using the nozzle piezoelectric element gap portion of the droplet ejecting apparatus manufactured by the manufacturing method of the present embodiment. In this embodiment, the configuration of the droplet ejecting apparatus excluding the nozzle piezoelectric element gap is the same as that of the first embodiment.

  In the liquid droplet ejecting apparatus of this example, it was possible to perform ejection with uniform characteristics from a plurality of nozzles. That is, according to this example, it was possible to provide a liquid droplet ejecting apparatus that ensured sufficient printing stability.

  Furthermore, according to the liquid droplet ejecting apparatus of the present embodiment, the sacrificial layer and the piezoelectric element are formed inside the concave portion of the membrane so that the droplet discharge side of the nozzle opening is opposite to the concave portion of the membrane. Therefore, the distance between the nozzle hole and the recording paper can be shortened, and a droplet ejecting apparatus suitable for high-definition recording can be produced.

  A sixth embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a process diagram of a method for producing the nozzle piezoelectric element gap portion of the droplet ejecting apparatus of the present embodiment, and FIG. 10 is a sectional view of the droplet ejecting apparatus of the present embodiment.

  First, the manufacturing method of the nozzle piezoelectric element gap part of the droplet ejecting apparatus of the present embodiment will be described with reference to FIG. In FIG. 9, 1 is a nozzle forming member, 2 is a first mask layer, 3 is a sacrificial layer, 4 is a first electrode layer, 5 is a piezoelectric layer, 6 is a second electrode layer, 9 is a mask opening, and 10 is a nozzle. Aperture, 11 is a piezoelectric element, 12 is a fixed end, 13 is a free end, 14 is a nozzle piezoelectric element gap, 15 is an anisotropic etching hole, 16 is a sacrificial layer material, 17 is a recess, 18 is a membrane, 19 is the atmosphere A communication portion mask opening 20 is an air communication portion.

  First, as shown in FIG. 9A, a Si single crystal wafer having a (100) plane orientation was used as the nozzle forming member 1, and this was processed by ordinary anisotropic etching to form a recess 17 in part. Etching conditions were controlled so that the recess 17 had a depth of 150 μm, and a membrane 18 made of Si having a thickness of 20 μm was formed at the bottom.

  Subsequently, as shown in FIG. 9B, a 300 nm silicon nitride film was further deposited by LP-CVD to form the first mask layer 2 on the entire surface including the recess 17 of the nozzle forming member 1.

  Subsequently, as shown in FIG. 9C, a mask opening 9 and an air communication portion mask opening 19 were formed in the first mask layer 2. The mask opening 9 and the atmosphere communication portion mask opening 19 are formed by using a FIB (focused ion beam) etching apparatus. The mask opening 9 has a rectangular shape with a side of 2 μm, and the air communication portion mask opening 19 has a rectangular shape with a side of 5 μm. .

  Subsequently, as shown in FIG. 9D, the nozzle forming member 1 was anisotropically etched from the mask opening 9 and the air communication portion mask opening 19 to form anisotropic etching holes. This step was performed in the same manner as in Example 2. However, by controlling the etching time, an anisotropic etching hole was penetrated to the back surface of the nozzle forming member to form an opening on the back surface. A communication part 19 was formed. The nozzle opening 10 was a rectangle having a side of 7 μm, and the air communication part 19 was a rectangle having a side of 10 μm.

  Subsequently, as shown in FIG. 9 (e), a sacrificial layer 3 was formed on a part of the nozzle forming member 1. In this example, 10 μm of MgO was deposited as a sacrificial layer by a high frequency sputtering method, and unnecessary portions were removed by etching to form the sacrificial layer 3. At the time of film formation, the substrate is rotated in the same manner as in Example 3, and the substrate is arranged at a position where the sputtered particles are incident from an oblique direction from the target, and the openings of the mask opening 9 and the atmospheric communication portion mask opening 19 are formed. A thin film was deposited in a direction to block the opening, and the opening was formed to have a substantially flat surface together with the blocking. At this time, a small amount of the sacrificial layer material 16 entered from the mask opening 9 and the atmospheric communication portion mask opening 19 and deposited in the nozzle opening 10 and the atmospheric communication portion 20. Unnecessary portions are removed by a combination of photolithography and etching. In this embodiment, since the bottom of the recess 17 is processed, SU-8 (MicroChem Corporation) is used as a photoresist as a mask. Etching was performed by forming a resist pattern having a large ratio. Hereinafter, the photolithography process related to the processing of the bottom of the recess 17 in this example was performed in the same manner.

Subsequently, as shown in FIG. 9F, the first electrode layer 4, the piezoelectric layer 5, and the second electrode layer 6 were sequentially deposited. The first electrode layer 4 was formed by depositing Ti in a thickness of 5 nm and Pt in a thickness of 100 nm by high frequency sputtering. The piezoelectric layer 5 was formed by depositing ₃ μm of Pb (Zr _x Ti _(1-x) ) O ₃ . The conditions for forming the piezoelectric layer 5 are as follows: a target obtained by mixing and firing Pb _1.1 Zr _0.5 Ti _0.5 O _{x in} a ratio of 5: 1 Ar and O ₂ , The high frequency power was applied to 1.5 W / cm ² and the substrate temperature was 620 ° C. The second electrode layer 6 was formed by depositing 500 nm of Pt by high frequency sputtering.

  Subsequently, as shown in FIG. 9G, the first electrode layer 4, the piezoelectric layer 5, and the second electrode layer 6 were patterned by photolithography and etching to form a piezoelectric element pattern. Etching was performed by dry etching using plasma with Ar gas for the first electrode layer 4 and the second electrode layer 6, and wet etching using an acidic aqueous solution for the piezoelectric layer 5. The piezoelectric element pattern was a rectangular cantilever type having a length of 200 μm and a width of 50 μm.

  Subsequently, as shown in FIG. 9 (h), the first mask layer is protected by using a phosphoric acid aqueous solution as an etching solution after protecting a portion requiring protection such as a piezoelectric element portion with a protective film made of a photoresist (not shown). The sacrificial layer 3 made of 2 and MgO is removed by etching, and the free end 13 is released from the nozzle forming member 1 except for the fixed end 12 of the piezoelectric element pattern so that the piezoelectric element 11 has a gap of the nozzle piezoelectric element gap 14. Formed in the shape. In this embodiment, this step is performed by sealing the recess 17 formed in the nozzle forming member 1 with a sealing material (not shown) to protect the piezoelectric element pattern and the sacrificial layer. Etching solution was introduced from the communicating portion to remove the sacrificial layer by etching. The piezoelectric element 11 was formed with a length from the fixed end to the free end of 200 μm and a width of 50 μm, and the interval between the nozzle piezoelectric element gaps 13 was 10 μm. A plurality of piezoelectric elements 12 were formed so that the interval was 30 μm. The protective film was removed after this step. Further, the sacrificial layer material 16 deposited in the anisotropic etching hole in the step of FIG. 9D was removed by etching together with the sacrificial layer 3 and the first mask layer 2 in this step. In this example, 200 sets of piezoelectric elements and mask openings were formed in parallel with the above dimensions and intervals.

  With the manufacturing method described above, the nozzle piezoelectric element gap portion of the droplet ejecting apparatus of this example was manufactured.

  When the gap between the nozzle piezoelectric element gaps 13 of the nozzle piezoelectric element gap produced as described above was measured using a laser microscope, all the elements could be formed within ± 0.5 microns with respect to 7 μm.

  According to the manufacturing method of the present embodiment described above, the nozzle piezoelectric element gap was precisely controlled, and it was possible to produce a plurality of elements with extremely small spacing variations.

  Furthermore, compared to the case where a reinforcing material is separately joined to the thin plate of the nozzle forming member shown in Example 1 and Example 2, it has a configuration having no joint part, and avoids problems such as peeling of the joint part. Thus, a manufacturing method with higher yield can be provided.

  Furthermore, in the etching removal process of the sacrificial layer, the sacrificial layer was etched and removed by introducing an etching solution from the nozzle opening and the air communication portion, so that the entire device was immersed in the etching solution and etched. Compared with other examples, the time for the etching solution to contact the piezoelectric element can be reduced, and the deterioration of the protective film formed on the piezoelectric element or the deterioration or destruction of the piezoelectric element due to the penetration of the etching solution from the pinhole. The droplet ejection device could be manufactured with a higher yield.

  FIG. 10 shows a droplet ejecting apparatus using the nozzle piezoelectric element gap portion of the droplet ejecting apparatus manufactured by the manufacturing method of this example. In this embodiment, the configuration of the droplet ejecting apparatus excluding the nozzle piezoelectric element gap is the same as that of the first embodiment.

  In the liquid droplet ejecting apparatus of this example, it was possible to perform ejection with uniform characteristics from a plurality of nozzles. That is, according to this example, it was possible to provide a liquid droplet ejecting apparatus that ensured sufficient printing stability.

  Furthermore, according to the liquid droplet ejecting apparatus of the present embodiment, the sacrificial layer and the piezoelectric element are formed inside the concave portion on the membrane so that the liquid droplet ejection side of the nozzle opening is opposite to the concave portion of the membrane. Therefore, the distance between the nozzle hole and the recording paper can be shortened, and a droplet ejecting apparatus suitable for high-definition recording could be manufactured.

  Furthermore, according to the droplet ejecting apparatus of the present embodiment, since the atmosphere communicating portion can be formed simultaneously with the nozzle formation, the number of steps is reduced as a whole droplet ejecting apparatus, and the droplet ejecting apparatus can be manufactured at a lower cost. I was able to provide it. Further, the meniscus is formed in the very vicinity of the air communication part by providing the air communication part on the fixed end side of the piezoelectric element with respect to the nozzle opening, the part facing the piezoelectric element of the nozzle forming member. Since the position can be set on the fixed end side of the piezoelectric element with extremely high accuracy, the state of the ink around the piezoelectric element can be controlled with high accuracy, and more stable ejection characteristics can be obtained.

Process drawing of the manufacturing method of the nozzle piezoelectric element gap part of the droplet ejecting apparatus of the first embodiment Droplet ejecting apparatus of first embodiment Process drawing of manufacturing method of nozzle piezoelectric element gap portion of droplet ejecting apparatus of second and third embodiments Droplet ejecting apparatus of second and third embodiments Process drawing of the manufacturing method of the nozzle piezoelectric element gap part of the droplet ejecting apparatus of the fourth embodiment Droplet ejecting apparatus of the fourth embodiment Process drawing of the manufacturing method of the nozzle piezoelectric element gap part of the droplet ejecting apparatus of the fifth embodiment Droplet ejecting apparatus of fifth embodiment Process drawing of the manufacturing method of the nozzle piezoelectric element gap part of the droplet ejecting apparatus of the sixth embodiment Droplet ejecting apparatus of sixth embodiment Conventional droplet ejection device

Explanation of symbols

1, 101, 201 Nozzle forming member 2 First mask layer 3 Sacrificial layer 4, 104, 204 First electrode layer 5, 105, 205 Piezoelectric layer 6, 106, 206 Second electrode layer 7, 107, 207 Housing member 8 Second mask layer 9 Mask opening 10, 110, 210 Nozzle opening 11, 111, 211 Piezoelectric element 12, 112, 212 Fixed end 13, 113, 213 Free end 14, 114, 214 Nozzle piezoelectric element gap 15 Anisotropic Etching hole 16 Sacrificial layer material 17 Recess 18 Membrane 19 Atmospheric communication part mask opening 20 Atmospheric communication part 120, 220 Ink 121, 221 Ink tank 122, 222 Ink supply part 123, 223 Ink introduction guide 124, 224 Ink introduction path 125, 225 Case 126, 226 Filter 127, 227 Ink heating mechanism 128, 129, 228, 229 Atmospheric communication portion 130, 230 Open end 131, 231 Wiring 132, 232 Ink droplet 233 Spacer

Claims (39)

A nozzle forming member having a plurality of nozzle openings, and a plurality of piezoelectric elements provided in the ink so as to face each of the nozzle openings, the nozzle piezoelectric member having a predetermined interval between the nozzle forming member and the piezoelectric elements. A method of manufacturing a droplet ejecting apparatus having a configuration arranged with an element gap, at least,
(1) A step of forming nozzle holes in the nozzle forming member (2) A step of forming a sacrificial layer on the nozzle forming member for forming a nozzle piezoelectric element gap by etching removal in a later step (3) The sacrifice A step of forming a piezoelectric element formed on a layer and having a fixed end bonded on a nozzle forming member. (4) A droplet comprising a step of etching away the sacrificial layer to form a nozzle piezoelectric element gap. Manufacturing method of injection device. Forming a nozzle hole in the nozzle forming member,
(1) Step of forming a mask layer on the nozzle forming member (2) Step of forming a minute mask opening in the mask layer (3) At least a step of etching the nozzle forming member from the mask opening to form an etching hole 2. The method for manufacturing a droplet ejecting apparatus according to claim 1, wherein a step of forming a sacrificial layer and a piezoelectric element on the mask layer is performed after an approximate step.   2. The nozzle forming member according to claim 1, wherein a part of the nozzle forming member is processed by etching or cutting to form a recess and a membrane, and a sacrificial layer, a piezoelectric element, and a nozzle hole are formed on the membrane. A method for manufacturing a droplet ejecting apparatus.   4. The method for manufacturing a droplet ejecting apparatus according to claim 3, wherein the sacrificial layer and the piezoelectric element are formed inside the concave portion on the membrane.   2. The droplet ejecting apparatus according to claim 1, wherein in the step of etching away the sacrificial layer to form a nozzle piezoelectric element gap, the sacrificial layer is etched away by introducing an etchant from the nozzle opening. Manufacturing method.   2. The method for manufacturing a droplet ejecting apparatus according to claim 1, further comprising a step of forming an air communication portion on the nozzle forming member.   7. The liquid droplet according to claim 6, wherein the atmosphere communication portion is a portion facing the piezoelectric element of the nozzle forming member and is formed on the fixed end side of the piezoelectric element with respect to the nozzle opening. Manufacturing method of injection device.   8. The sacrificial layer is etched away by introducing an etchant from the atmosphere communicating portion in the step of forming the nozzle piezoelectric element gap by etching away the sacrificial layer. A method for manufacturing a droplet ejecting apparatus.   2. The method for manufacturing a droplet ejecting apparatus according to claim 1, wherein the sacrificial layer is formed by depositing a sacrificial layer material from a gas phase.   2. The method for manufacturing a droplet ejecting apparatus according to claim 1, wherein the sacrificial layer is formed by depositing a sacrificial layer material from a liquid phase.   2. The method for manufacturing a droplet ejecting apparatus according to claim 1, wherein the sacrificial layer is formed by applying a sacrificial layer material.   2. The method of manufacturing a droplet ejecting apparatus according to claim 1, wherein the sacrificial layer has a thickness of 1 μm to 50 μm.   The method for manufacturing a droplet ejecting apparatus according to claim 1, wherein an organic material is used as the sacrificial layer material.   14. The method for manufacturing a droplet ejecting apparatus according to claim 13, wherein the organic material used as the sacrificial layer material is a photosensitive resin.   The method for manufacturing a droplet ejecting apparatus according to claim 1, wherein an inorganic material is used as the sacrificial layer material.   The method for manufacturing a droplet jetting device according to claim 15, wherein the inorganic material used as the sacrificial layer material is MgO.   The method for manufacturing a droplet ejecting apparatus according to claim 15, wherein the inorganic material used as the sacrificial layer material is silicon oxide.   16. The method for manufacturing a droplet ejecting apparatus according to claim 15, wherein the inorganic material used as the sacrificial layer material is polysilicon.   16. The method for manufacturing a droplet ejecting apparatus according to claim 15, wherein the inorganic material used as the sacrificial layer material is a metal.   A nozzle forming member having a plurality of nozzle openings, and a plurality of piezoelectric elements provided in the ink so as to face each of the nozzle openings, the nozzle piezoelectric member having a predetermined interval between the nozzle forming member and the piezoelectric elements. A droplet ejecting apparatus having a configuration arranged with an element gap, wherein a fixed end of a piezoelectric element is fixed to a nozzle forming member, and a nozzle piezoelectric element having a sacrificial layer thickness between the free end of the piezoelectric element and the nozzle forming member A droplet ejecting apparatus having a structure having an element gap.   21. The droplet ejecting apparatus according to claim 20, wherein the nozzle forming member has a thickness of 1 μm to 50 μm.   21. The droplet ejecting apparatus according to claim 20, wherein a semiconductor material is used as the nozzle forming member.   The liquid droplet ejecting apparatus according to claim 22, wherein the semiconductor material used as the nozzle forming member is a silicon single crystal.   21. The droplet ejecting apparatus according to claim 20, wherein a conductive material is used as the nozzle forming member.   The liquid droplet ejecting apparatus according to claim 24, wherein the conductive material used as the nozzle forming member is a metal.   21. The droplet ejecting apparatus according to claim 20, wherein an insulating material is used as the nozzle forming member.   27. The droplet ejecting apparatus according to claim 26, wherein the insulating material used as the nozzle forming member is a photosensitive resin.   27. The droplet ejecting apparatus according to claim 26, wherein the insulating material used as the nozzle forming member is a glass material. 21. The droplet ejecting apparatus according to claim 20, wherein an aperture area of the nozzle is 1 × 10 ⁻¹¹ m ^{2 to} 1 × 10 ⁻⁹ m ² .   21. The droplet ejecting apparatus according to claim 20, wherein the piezoelectric element has a thickness of 1 μm to 50 μm.   21. The droplet ejecting apparatus according to claim 20, wherein a perovskite oxide piezoelectric material is used as a piezoelectric layer material used for the piezoelectric element.   21. The droplet ejecting apparatus according to claim 20, wherein an interval between the nozzle piezoelectric element gaps is 1 μm to 50 μm.   21. The liquid according to claim 20, wherein a part of the nozzle forming member is processed by etching or cutting to form a recess and a membrane, and a sacrificial layer, a piezoelectric element, and a nozzle hole are formed on the membrane. Drop ejector.   34. The droplet ejecting apparatus according to claim 33, wherein the sacrificial layer and the piezoelectric element are formed inside the recess on the membrane.   21. The liquid droplet ejecting apparatus according to claim 20, wherein the nozzle forming member has an air communication part.   36. The droplet ejecting apparatus according to claim 35, wherein the atmosphere communication portion is a portion facing the piezoelectric element of the nozzle forming member and provided on the fixed end side of the piezoelectric element with respect to the nozzle opening. .   36. The droplet ejecting apparatus according to claim 35, wherein an opening area of the atmosphere communicating portion is larger than an opening area of the nozzle opening. 36. The droplet ejecting apparatus according to claim 35, wherein an opening area of the atmosphere communication portion is 5 × 10 ⁻¹¹ m ^{2 to} 5 × 10 ⁻⁷ m ² .   21. The droplet ejecting apparatus according to claim 20, further comprising a mechanism that applies individually controlled driving voltages to the piezoelectric elements.

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