JP2006076180A - Inkjet printer head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet printer head which is excellent in erosion resistance and long term reliability, and is suitable for jetting various types of inks such as an acid based ink, an alkali based ink, and solvent based ink. <P>SOLUTION: This inkjet printer head is constituted in a manner to jet an ink by the action of vibration plates made of a piezoelectric body. For the inkjet printer head, a plate-like spacer is inserted between the two vibration plates made of the piezoelectric body, and also, a liquid passage and a liquid feeding path are defined by the vibration plates and the spacer 200, and the vibration plates and the spacer which are bonded to each other are made a basic unit. A plurality of the basic units are stacked to form a stacked piezoelectric body. The stacked piezoelectric body is further bonded to a nozzle plate 300, on which a jetting hole communicating with the liquid passage is formed. At the bonded sections of the spacer, the vibration plates, and the nozzle plate, a metal layer is respectively formed to coat them, so that they are bonded to each other by metal bonding. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a structure of an ink jet printer head capable of ejecting a relatively high viscosity ink at high speed and efficiently, and in particular, a structure of an ink jet printer head capable of ejecting various inks such as acid, alcohol and alkali. About.

Various types of ink jet printers, so-called ink jet printers, have been proposed. As one of these, a bubble jet (thermal) has a structure in which a heater disposed in the vicinity of a nozzle is instantaneously heated, ink in the vicinity of the heated heater is bumped, and ink droplets are ejected from the nozzle by the pressure. There is a method.
In addition, a piezoelectric (piezoelectric element) method has a structure in which when a voltage is applied to a piezoelectric element, the piezoelectric element expands and contracts, and the diaphragm vibrates accordingly, thereby ejecting ink droplets from the nozzle. (For example, refer to Patent Document 1).
This piezo-type ink jet printer head has a configuration in which a vibration plate made of a piezoelectric element that expands and contracts when a voltage is applied is joined to the ink ejection port on the opposite side or the side surface. Accordingly, ink droplets can be ejected from the ink ejection ports. In such a type, a piezoelectric element and a substrate on which ink ejection ports are formed are usually joined by an adhesive.

JP 56-89956 A

However, the conventional ink jet printer head employing the piezo method has a problem that the ink composition to be used is limited. That is, there is a problem that only ink that does not dissolve or swell the adhesive that adheres the piezoelectric element and the substrate on which the ink ejection port is formed can be used.
For example, if the adhesive dissolves, the adhesive surface peels off and ink leakage occurs, resulting in insufficient pressure transmission to the ink, making it impossible to eject ink, or ink Adhesive components are mixed therein, causing problems such as ink not having the desired color. Therefore, even if it is used for an ink jet printer head, the range of use is limited and lacks versatility.
Accordingly, a main object of the present invention is to provide an inkjet printer head having excellent corrosion resistance and high long-term reliability.
Another object of the present invention is to provide an ink jet printer head adapted to eject various types of ink such as acid, alcohol, organic solvent and alkali.

As a result of diligent research to achieve the above-mentioned object, the present inventors have completed the present invention having the following contents.
That is, the present invention
In an inkjet printer head configured to eject ink by the action of a diaphragm made of a piezoelectric body,
A plate-like spacer having a groove for forming an ink flow path and an opening for forming an ink supply path continuous therewith, and having a metal layer on at least the surface;
An insulating film that has an opening that communicates with the ink supply path forming opening of the spacer, and that is provided with an electrode corresponding to the groove for forming the ink flow path of the spacer on at least one surface, and the insulating film A diaphragm made of a piezoelectric body further provided with a metal layer;
A nozzle plate having an injection hole at a position corresponding to the ink flow path forming groove of the spacer and having a metal layer provided at a joint portion between the spacer and the vibration plate;
The vibration plate and the spacer are alternately laminated to form a laminated piezoelectric body in which an ink flow path and an ink supply path are formed, and the nozzle plate is disposed on the ink ejection side of the laminated piezoelectric body, and the vibration An ink jet printer head characterized in that a plate, a spacer, and a nozzle plate are joined to each other through their metal layers.

In the present invention, the spacer laminated alternately with the diaphragm can be provided with a metal layer on the entire surface including the wall portion of the ink channel forming groove and the wall portion of the ink supply channel forming opening.
In the present invention, the spacers alternately stacked with the diaphragm can be made of a material mainly made of Si or SiO ₂ .
In the present invention, the laminated piezoelectric body can be configured such that a spacer is sandwiched between diaphragms.
Furthermore, in the present invention, the metal layers respectively formed on the diaphragm, the spacer, and the nozzle plate are formed from the same metal, and can be formed from gold or copper.

  According to the ink jet printer head of the present invention, since the diaphragm, the spacer, and the nozzle plate are joined by metal joining without using an adhesive, excellent corrosion resistance and long-term reliability can be obtained. At the same time, it can be adapted to the ejection of various types of inks such as acid, alcohol, organic solvent, and alkali without considering the characteristics of the ink used.

Hereinafter, specific embodiments of an inkjet printer head according to the present invention will be described with reference to the accompanying drawings.
The ink jet printer head according to the present invention is characterized in that a plate-like spacer is interposed between two diaphragms made of a piezoelectric material, and a liquid channel and a liquid supply channel are defined by the diaphragm and the spacer. A unit obtained by joining spacers to each other as a basic unit, a plurality of these units are laminated to form a laminated piezoelectric body, and a nozzle plate having an injection hole communicating with the liquid flow path is further joined to the laminated piezoelectric body. In this configuration, the metal layer is formed on the joining portion of the spacer, the diaphragm, and the nozzle plate, and is joined to each other by metal joining.

According to the above configuration, the external formability is excellent, and the degree of freedom in forming the electrode position is increased, so that the degree of freedom in design is increased, and even when the ink droplets contain acid or alkali, the same applies. It can be sprayed.
In the present invention, the material for forming the diaphragm is preferably formed of a piezoelectric ceramic containing PZT (Pb (Zr, Ti) O ₃ ) as a main component. As these piezoelectric ceramics, materials having a large piezoelectric constant and electromechanical coupling coefficient, a high Curie point, a low dielectric constant, and a small dielectric and mechanical loss are preferable.

The Pb (Zr, Ti) O ₃ ceramic is specifically described, for example, Pb (Mg _1/3 Nb _2/3 ) O ₃ —PbZrO ₃ —PbTiO ₃ , Pb (Y _1/3 Nb _1/3 ). O ₃ —PbZrO ₃ —PbTiO ₃ , Pb (Mn _1/3 Nb _1/3 ) O ₃ —PbZrO ₃ —PbTiO ₃ , Pb (Co _1/3 Nb _1/3 ) O ₃ —PbZrO ₃ —PbTiO ₃ Can be mentioned.

Other than these, for example, a composition in which a piezoelectric material such as Sr (K _0.25 · Nb _0.75 ) O ₃ or Sr (W _0.25 · Nb _0.75 ) O ₃ is dissolved in PZT is known. These piezoelectric materials have a high Curie point and are used in products such as sensors.

  As shown in FIG. 1, the piezoelectric body 10 used in the present invention is formed into a plate shape as will be described later, and the spacer 200 is in contact with both surfaces of the spacer 200 that is also formed into a plate shape. Are arranged so as to block the ink flow path forming kerf 32 provided in the ink flow path, and are joined to the spacer 200. That is, the ink flow path 33 is formed by a region surrounded by the upper wall and the bottom wall of the ink flow path forming groove 32 of the spacer 200 and the surface of each piezoelectric body 10 facing each other.

As shown in FIGS. 2 and 3, one electrode 14 for applying voltage is provided on the opposing surface of each piezoelectric body 10 at a position along the ink flow path 32, and on the opposite side of each piezoelectric body. The other electrode 14 for applying voltage is also provided on the surface.
These voltage application electrodes 14 preferably have approximately half the width of the ink flow path 33 and are disposed along the ink flow path 33. This is because the deformation efficiency of the piezoelectric body is the best.

  As shown in FIG. 4, the voltage application electrode 14 is connected to an arbitrary portion of the piezoelectric body 10, for example, an upper end portion of the piezoelectric body, via a conductor path 18 extending from the electrode 14 along the ink flow path 33. Is electrically connected to the extraction electrode (power feeding pad) 16 provided in

By applying a voltage to the electrode 14, the piezoelectric body is deformed and the volume of the ink flow path 33 is changed. When the volume of the ink flow path 33 is reduced, ink in the ink flow path is ejected, and when the flow path volume is increased, new ink is supplied from an ink tank (not shown). It has become so.
As the driving mode of the piezoelectric body in the present _invention, it is possible to drive _{d 33 mode, d 31 mode,} either _{d 15} mode. That is, by using these modes, ejection of droplets such as ink is not hindered, and variations in droplet ejection speed and size do not occur. In addition, two or more modes among these modes can be mixed and used.

Each piezoelectric body 10 has an opening 12 that communicates with the ink supply path forming opening 34 of the spacer 200 so that the ink supply path is formed when the piezoelectric bodies 10 are stacked with the spacer 200 interposed therebetween. It has become.
Further, each piezoelectric body 10 is provided with an insulating protective film 20 that covers a portion of the conductor path 18 such as the voltage application electrode 14 and the power supply pad 16 except for the power supply pad 16, and will be described later. A bonding metal layer 22 is provided in a portion corresponding to the bonding portion between the spacer 200 and the nozzle plate 300.

The insulating protective film 20 is formed of an inorganic film such as Si ₃ N ₄ or SiO ₂ or an organic film such as an epoxy resin or PI, and is provided on the piezoelectric body by a method such as sputtering, CVD, or coating.
The thickness of the insulating protective film 20 is preferably about 0.05 to 5 μm. If the thickness is less than 0.05 μm, sufficient insulation cannot be ensured. On the other hand, if the thickness exceeds 5 μm, the film stress is increased in the inorganic film, and cracks are likely to occur. This is because the displacement is absorbed and the pressure cannot be sufficiently transmitted to the ink.

In the present invention, the spacer 200 sandwiched between the pair of vibration plates 100 made of the piezoelectric body 10 is preferably formed in a plate shape using an insulating resin, metal, ceramics, inorganic material, or the like.
These materials may be used alone or in a composite in which two or more kinds of materials are combined.
Examples of the insulating resin include thermoplastic resins, thermosetting resins, photosensitive resins, and composite resins thereof.
Examples of the thermoplastic resin include ABS resin, polyimide, polyamide, and polyester.

As said thermosetting resin, an epoxy resin, a phenol resin, a polyimide resin, an acrylic resin etc. are used, for example.
In addition, as the metal, for example, copper, nickel, zinc, aluminum, SUS, Kovar, 42 alloy, iron, titanium, chromium or the like, or an alloy thereof can be used.
As the ceramic, for example, glass ceramic, alumina, mullite, aluminum nitride, silicon carbide, or the like can be used.
Furthermore, as the inorganic material, for example, Si, SiO ₂ , carbon (including carbide) can be used.

The basic characteristics required for the material used for the spacer 200 in the present invention are that at least the liquid channel forming kerf 32 and the liquid supply port forming opening 34 can be formed, and that the flatness is excellent, That is, a metal layer can be formed on the surface layer.
Among these materials forming the spacer 200, in particular, it is preferable to use Si or SiO _2. This is because these materials can easily maintain the flatness of the substrate, and the difference in thermal expansion coefficient from the piezoelectric body is small, so that problems such as deformation do not occur. Furthermore, it is possible to easily form a protective film such as an oxide film, and is excellent in external formability by etching or the like.
The spacer 200 according to the present invention is made of the material as described above, so that vibrations generated by the two diaphragms 100 bonded to both surfaces thereof are transferred to the liquid in the liquid flow path 33 formed in the spacer 200. Can communicate effectively.

In the present invention, metal layers 22 and 38 are respectively formed on the joint surface between the vibration plate 100 and the spacer 200, and the metal layer is also formed on the joint surface between the vibration plate 100 and the spacer 200 and the nozzle plate 300. Is formed.
As these metal layers, metals such as gold, copper, nickel, titanium, zinc, and aluminum are formed as a single layer or a plurality of layers of two or more layers, or solder or brazing materials (silver brazing, gold brazing, etc.) ).
This is because these metals can be bonded to each other even at a relatively low temperature and have excellent adhesion.
As the method for forming the metal layer, it is desirable to use a chemical formation method such as electrolytic plating or electroless plating, or a physical formation method such as sputtering, vapor deposition, or CVD, and a plurality of metal layers are formed. If so, they may be formed by the same forming method or by different forming methods.
Such a metal layer is formed not only on the spacer 200 but also on the diaphragm 100 and the nozzle plate 300 made of the piezoelectric body 10, at least on the surfaces to be joined to each other.
That is, it is configured such that a joining portion of the diaphragm 100, the spacer 200, and the nozzle plate 300 made of the piezoelectric body 10 is covered with a metal film, and the joining portions are heated and pressurized to be joined to each other and adhered to each other. ing.

The metal film that covers the bonding surfaces of the diaphragm 100, the spacer 200, and the nozzle plate 300 made of the piezoelectric body 10 is preferably formed of the same metal, and as such a metal, either gold or copper is used. It is preferable to use it.
The reason is that since the thermal expansion coefficients at the respective joint surfaces are the same, peeling and peeling caused by stress such as thermal expansion in the vicinity of the joint surfaces can be prevented.
The thickness of the metal layer is preferably about 0.01 to 3 μm. The reason is that if the thickness is less than 0.01 μm, bonding may not be possible. On the other hand, if the thickness exceeds 3 μm, breakage, cracks, etc. are likely to occur in the formed metal film, resulting in a decrease in bonding strength. It is to do.

In addition, it is desirable to previously wash the metal surfaces to be joined. That is, an oxide film, a nitride film, or the like may be formed on the metal surface before bonding, or may be contaminated with oil components or the like. May decrease. Therefore, it is desirable to remove the oxide film, the nitride film, etc. in advance to remove the contaminants.
It is preferable that the metal bonding is performed under the conditions of temperature: 50 to 300 ° C., pressure: 0.01 to 100 MPa, and bonding time: 0.5 minutes or more. The reason is that the metal film is not activated at a temperature lower than 50 ° C., so that strong metal bonding may not be possible. Conversely, if the temperature exceeds 300 ° C., the oxidation of the metal film proceeds and the bonding strength is increased. This is because it lowers. If it is between 50-300 degreeC, it is because joining between metals can be performed and joining strength can also be stabilized.

Further, when the pressure is less than 0.01 MPa, metal bonding cannot be performed. On the other hand, if the pressure exceeds 100 MPa, the metal film formed at the bonding site is broken, and the strength of the metal bonding is lowered.
Furthermore, if the bonding time is less than 0.5 minutes, the time is too short and soaking does not proceed, so that stable metal bonding cannot be performed.

  In the present invention, the final bonding may be performed after temporary bonding is performed at a temperature and pressure conditions lower than the above-described temperature and pressure. In addition, when laminating three or more layers of diaphragms, they may be collectively laminated and then joined together, or may be sequentially laminated such that individual metal joints are further laminated. Good.

  Moreover, in the metal joining with the same metal of gold-gold, it is desirable to carry out under the conditions of temperature: 50 to 250 ° C., pressure: 10 to 100 MPa, joining time: 1 minute or more. A lamination method or a sequential lamination method may be used.

Moreover, in the metal joining by the same metal of copper-copper, it is desirable to carry out under the conditions of temperature: 80 to 150 ° C., pressure: 0.01 to 35 MPa, and joining time: 0.5 minutes or more. The batch stacking method or the sequential stacking method may be used.
However, in the case of performing metal bonding with copper-copper, adhesion strength is improved when the oxide film (copper oxide such as CuO) on the bonding surface is removed in advance by acid treatment and then bonded.

In the ink jet according to the present invention, the diaphragm 100 made of the piezoelectric body 10, the spacer 200, and the nozzle plate 300 are integrated with each other by metal bonding without using an adhesive as in the prior art. Limitations due to ink properties (acid, alkali, solvent content, etc.) are greatly reduced.
That is, unlike the prior art, the adhesive intervening on the joint surface of the diaphragm 100 is not dissolved, and components such as the adhesive are not mixed in the ink. It will not cause alteration or discoloration.
Therefore, in the ink jet according to the present invention, it is possible to use various types of inks each having acid, alkali, alcohol or solvent as main components.

As the ink having the acid as a main component, an ink having an acid solution as a main component such as acetic acid, butyric acid, hydrochloric acid, and nitric acid can be used.
Further, as the ink mainly composed of alkali, inks mainly composed of alkaline solutions such as NaOH and KOH can be used.
Further, as the ink mainly containing alcohol, inks mainly containing alcohols such as methanol, ethanol, isopropyl alcohol, and butanol can be used.
Further, as the ink having a solvent as a main component, an ink having a solvent as a main component such as acetates, glycol ethers and ketones can be used.
Specific examples of the solvent include toluene, xylene, ethyl acetate, butyl acetate, normal brovir acetate, acetone, MEK (methyl ethyl ketone), swazole, sorbeso, eticello, buticello, celloace, hexane, and anone.
Since such an ink is not mixed with an adhesive or the like as in the prior art, the ink jet of the present invention can eject a desired type of ink.
Hereinafter, the ink jet printer head of the present invention will be described in more detail based on examples.

(A) Manufacturing process of piezoelectric body Lead zirconium titanate (hereinafter referred to as “PZT”) as a piezoelectric material was manufactured by the following processes.
(1) Raw material blending First, the molar fractions and additive amounts of a plurality of ceramic materials used for PZT production are converted into the weight ratio of the raw materials and weighed and blended.
PbO (or Pb ₃ O ₂ ), ZrO ₂ , and TiO ₂ constituting Pb (Zr, Ti) O ₂ are made into powder, and other additive components are also made into powder, and their prescribed amounts are prepared.
The purity of these raw material powders is preferably 98% or more, and it is preferable to know in advance the types of impurities contained in the raw material used, the particle size distribution, and the like.

(2) Mixed pulverization The raw material and pure water prepared in (1) above were added to a ball mill, and mixed and pulverized under the conditions of a rotational speed of 150 to 650 rpm and a mixing time of 12 to 24 hours.
The mixing and pulverizing steps are performed so that the prepared raw materials and pure water are uniformly mixed and pulverized. This is because the non-uniformity has a great influence on the reactivity at the time of pre-baking and the piezoelectric characteristics in the final product.
(3) Temporary calcination The raw material mixed and pulverized in (2) above is dried at a temperature of 80 to 150 ° C. for about 30 to 240 minutes, and after removing excess moisture in advance, the temperature is 800 to 900 ° C. for an hour. Pre-baking is performed in about 30 to 60 minutes, and a solid phase reaction is performed in advance in a powder state.
(4) Mixed pulverization The raw material preliminarily calcined in (3) and pure water were added to a ball mill, and mixed and pulverized under the conditions of a rotational speed of 150 to 650 rpm and a mixing time of 12 to 36 hours.

(5) Binder formulation A binder (binder) was uniformly added to the mixture obtained in the above (4) to obtain a pre-molding stage.
As the binder, an acrylic binder, PVA, PVB, or the like can be used.
The weight ratio of the binder is preferably 0.5% or less.
If the weight ratio exceeds 0.5%, molding can be facilitated and mechanical strength can be obtained, but electrical characteristics and piezoelectricity are deteriorated. Moreover, it is because the reduction | restoration of an oxide becomes easy to be accelerated | stimulated.
(6) Molding A raw material powder having a particle size of 0.05 to 10 μm was molded into a molded body having a predetermined shape.
(7) Firing The molded body obtained in (6) above has a temperature of 900 to 1300 ° C. and a holding time:
Calcination is performed for 30 minutes to 3 hours.
(8) Polishing, cutting, and surface finishing In order to obtain a predetermined size for the sintered piezoelectric material, polishing, cutting, and surface finishing are performed.

(9) Electrode baking This is a step of forming an electrode for use as a polarization treatment or a piezoelectric body. As an example, there is a method in which a silver paste is applied to a piezoelectric material and baked at 500 to 800 ° C. In addition, the electrode may be formed by electroless plating, vacuum deposition, or sputtering. In addition to silver, metals such as gold, nickel, copper, titanium, zinc, and aluminum can be formed of a single layer or a plurality of layers of two or more layers.
The thickness of the electrode is desirably 0.1 to 5 μm. The reason is that if the thickness is less than 0.1 μm, the resistance is high and polarization is difficult, whereas if the thickness exceeds 5 μm, it is uneconomical.
(10) Polarization treatment Since a sintered piezoelectric material such as PZT is isotropic and does not have piezoelectricity, in order to impart piezoelectricity thereto, a direct current electric current exceeding the coercive electric field of the piezoelectric material is provided. A polarization process is performed by applying a field and aligning the direction of spontaneous polarization to give a polarity.
For example, in insulating oil at around 80 to 150 ° C., polarization is performed while applying a direct current electric field of 1 to 5 kv / min and holding for several tens of minutes. Through this polarization step, the piezoelectric material becomes a piezoelectric body having piezoelectricity. In this embodiment, the polarization direction of the piezoelectric body is a direction perpendicular to the electric field direction (share mode).

(B) Diaphragm manufacturing process
(1) Processing of plate-like body PZT as the piezoelectric material manufactured in (A) is processed into a plate shape having a thickness of 80 to 90 μm, and the plate-like body is further processed to a predetermined size, for example, 5 mm. The piezoelectric element plate 10 was cut by × 7 mm.
The piezoelectric element plate 10 is drilled using a processing tool such as a drill to form an ink supply port 12 having an opening diameter of 1 mm (see FIG. 6A). Thereafter, the surface of the piezoelectric element plate 10 was polished and smoothed. As an example of polishing, rough polishing (particle name: GC # 4000) and mirror polishing (colloidal silica) were performed in two stages, and the thickness of the piezoelectric element plate 10 was smoothed. Accordingly, the thickness of the piezoelectric element plate 10 is 70 μm, and the average roughness (Ra: JIS) of the surface thereof.
B0601) was made 0.1 μm or less.

(2) Conductor layer formation A dry film resist layer (product name: SPG-152, manufactured by Asahi Kasei Electronics Co., Ltd.) was formed on the entire surface of the piezoelectric element plate 10 prepared by the step (1). This resist layer may be formed by applying a resist solution without using a dry film.
A mask on which a conductive layer pattern 18 including a voltage applying electrode 14 for forming an electric field on the piezoelectric element plate 10 and a power supply pad 16 for connecting the electrode to the outside is drawn is placed on the dry film resist layer. Then, the resist is exposed at an exposure amount of 80 mj / cm ² and then developed with an aqueous alkali solution containing sodium or the like, whereby a resist having a non-resist forming portion corresponding to a mask pattern on the piezoelectric element plate 10. A layer was formed.
A conductive layer pattern 18 having a two-layer structure is formed by forming a titanium layer on the resist non-formation portion of the resist layer by a physical method such as vapor deposition or sputtering, and further forming a gold layer on the titanium layer. Were formed on the front and back surfaces of the piezoelectric element plate 10 (see FIG. 6B).
In the case of forming the conductive layer pattern 18 by sputtering, for example, using a sputtering apparatus (manufactured by Shibaura Seisakusho Co., Ltd., product name: CFS-4ES-231), the degree of vacuum: 5.0 × 10 ⁻⁴ Pa, power Sputtering is performed under the conditions of amount: 100 W and sputtering time: 18 minutes to form a titanium layer having a thickness of 0.03 to 0.06 μm.
Then, on the titanium layer, using the same sputtering apparatus, the thickness is 0.05 to 0.00 under the conditions of vacuum degree: 5.0 × 10 ⁻⁴ Pa, electric energy: 200 W, and sputtering time of 5 minutes. A 3 μm gold layer is formed to form a conductive layer pattern 18 having a three-layer structure of titanium-tantalum-gold.
Thereafter, using a 10% aqueous sodium hydroxide solution, the resist layer and the metal layer on the resist layer surface are peeled off and removed by a lift-off method, so that the voltage application electrode 14 and the power supply pad 16 are formed on both surfaces of the piezoelectric element plate 10. A conductor layer pattern 18 was formed.

(3) Insulating protective film formation A transfer sheet made of a polyimide resin, in which a portion corresponding to the power supply pad 16 has been cut out in advance on the piezoelectric element plate formed in the step (2), is formed at a temperature of 150 to 250 ° C. and a pressure of 1 The insulating protective layer 20 was formed in a state where only the power supply pad 16 was exposed in the conductor layer pattern 18 on the piezoelectric element plate 10 by thermocompression bonding under a condition of 0.5 kg / cm ² (see FIG. 6C).
(4) Formation of bonding metal layer On the piezoelectric element plate 10 on which the insulating protective film 20 is formed in the above (3), a mask having a portion corresponding to the power supply pad 16 is placed to cover the power supply pad 16. And the metal layer 22 for joining was formed in such a covering state (refer FIG.6 (d)). The mask is removed after the metal layer 22 is formed on the piezoelectric element plate 10. The power supply pad 16 can be covered without forming a mask by forming the metal layer 22 in a state where the power supply pad 16 is covered and protected with a resist layer, and then chemically removing the resist layer.
The metal layer 22 is, for example, a sputtering apparatus (product name: CFS-4ES-231 manufactured by Shibaura Seisakusho Co., Ltd.) in a state where a mask having a portion corresponding to the power supply pad 16 is placed on the piezoelectric element plate 10. Is used to perform sputtering treatment under conditions of vacuum degree: 5.0 × 10 ⁻⁴ Pa, electric energy: 100 W, sputtering time: 18 minutes, and a thickness of 0.03 to 0.06 μm on the polyimide layer. The titanium layer was formed.
Similarly, a gold layer having a thickness of 1.0 μm was formed on the titanium layer under the conditions of vacuum degree: 5.0 × 10 ⁻⁴ Pa, electric energy: 200 W, sputtering time: 30 minutes, The mask covering the power supply pad 16 was removed.
As a result, a metal layer 22 having a titanium-gold two-layer structure was formed on the entire surface other than the power supply pad 16.

(C) Spacer manufacturing process
(1) Mask layer formation First, a silicon wafer having a diameter of 4 inches and a thickness of 70 μm is prepared (see FIG. 7A).
A dry film resist layer (product name: SPG-152 manufactured by Asahi Kasei Co., Ltd.) is formed on the entire surface of the silicon wafer. The resist layer may be formed by applying a resist solution without using a dry film.
A mask on which a portion 36 containing the ink flow path 32, the ink supply port 34, and the power supply pad 16 is drawn is placed on the dry film resist layer and exposed at an exposure amount of 80 mj / cm ² . By developing with an alkaline aqueous solution containing sodium or the like, an ink flow path 32, an ink supply port 34, a power supply pad accommodating portion 36, and a resist non-formation portion corresponding to the outer shape of the piece were formed on the plate-like silicon 30.

(2) Etching of plate-like silicon The plate-like silicon 30 having the resist layer formed in the step (1) was dry-etched with a fluorine-based gas or a halogen-based gas.
This dry etching process is performed using, for example, a dry etching apparatus (manufactured by Tokyo Electron Ltd.), under conditions of RF power: 600 W, gas flow rate SF ₆ / O ₂ = 130/10 sccm, etching time: 40 minutes. By irradiating a gas such as a fluorine-based gas toward the resist non-forming portion of the layer, the ink flow path 32, the ink supply port 34, and the power supply pad accommodating portion 36 are formed on the plate-like silicon 30 (FIG. 7 ( b)).
Further, instead of dry etching, a wet etching process may be performed using a sulfuric acid-based, hydrochloric acid-based, or HF-based etchant, or an etching process based on a composite process thereof may be performed.
After the etching was completed, the resist layer was removed and removed with a 10% aqueous sodium hydroxide solution.

(3) Formation of bonding metal layer A bonding metal layer 38 was formed on the silicon substrate obtained in the step (2) (see FIG. 7C).
The metal layer for bonding 38 is, for example, using a sputtering apparatus (manufactured by Shibaura Seisakusho, product name: CFS-4ES-231), with a degree of vacuum of 5.0 × 10 ⁻⁴ Pa, an electric energy of 100 W, and a sputtering time. Under the condition of 18 minutes, a titanium layer having a thickness of 0.03 to 0.06 μm was formed, and on the titanium layer, 5.0 × 10 ⁻⁴ Pa, electric energy using the same sputtering apparatus. : A gold layer having a thickness of 1.0 μm was formed under the conditions of 200 W and a sputtering time of 30 minutes to coat a titanium-gold two-layer metal film on the entire surface of the silicon plate.

(D) Manufacturing process of nozzle plate
(1) Mask layer formation First, a silicon wafer having a diameter of 4 inches and a thickness of 70 μm is prepared.
Next, a dry film resist (manufactured by Asahi Kasei Electronics Co., Ltd., product name: SPG-152) is attached to the entire surface of one side of the silicon wafer 50 to form a resist layer. The resist layer may be formed by applying a resist solution without using a dry film.
Next, a mask in which openings having a diameter of 30 to 50 μm are drawn at a pitch of 150 μm is placed on the dry film resist layer, exposed at an exposure amount of 80 mj / cm ² , and then an alkaline aqueous solution containing sodium or the like. The resist non-formation part corresponding to a mask pattern was formed on the silicon | silicone by developing using.

(2) Etching of base material The plate-like silicon 50 having the resist layer formed in the step (1) was subjected to a dry etching process using a fluorine-based gas or a halogen-based gas.
The etching process is performed using, for example, a dry etching apparatus (manufactured by Tokyo Electron), RF power: 600 W, gas flow rate: SF ₆ / O ₂ = 130/10 sccm, etching time: 40 minutes. By irradiating a gas such as a fluorine-based gas toward the resist non-formation portion, droplet ejection holes 40 in which holes having an opening diameter of 30 to 50 μm are arranged at a pitch of 150 μm are formed (see FIG. 8).
Further, instead of the dry etching process, a wet etching process may be performed using a sulfuric acid-based, hydrochloric acid-based, or HF-based etchant solution. You may perform the etching process by those composite processes.
By performing a peeling process on the silicon subjected to the etching process, the mask layer formed on the plate-like silicon was removed. Depending on the type of ink used, the surface of silicon may be subjected to lyophilic or liquid repellent treatment with an inorganic film such as SiC, SiO ₂ or DLC, or an organic film such as silicone or Teflon.

(E) Lamination process (1) Lamination of diaphragm and spacer Diaphragm 100 produced in steps (1) to (4) of (B) and (1) to (3) of (C) The spacers 200 manufactured in the process are alternately stacked. At that time, the outermost layer is laminated so as to be the diaphragm 100 made of the piezoelectric element 10 (see FIG. 4).
Thereafter, alignment is performed so that the ink supply port 12 of the vibration plate 100 and the ink supply port 34 of the spacer 200 are matched, and then thermocompression bonding is performed under conditions of pressure: 10 to 100 MPa and temperature: 50 to 250 ° C. The laminated piezoelectric body 400 having a configuration in which the plurality of diaphragms 100 made of the piezoelectric elements 10 are arranged to face each other with the spacers 200 interposed therebetween is formed by holding the layers for about 1 minute or longer (see FIG. 5).

(2) Nozzle plate bonding The nozzle plate 300 manufactured in the above (C) was bonded to the laminated piezoelectric body 400 manufactured in the above (1) by the following steps (a) to (c).
(a) First, the surface to be the bonding surface of the nozzle plate 300 was polished to flatten the bonding surface. As the polishing method, it is desirable to use an abrasive such as colloidal silica, SiC, or diamond.
In this example, polishing was performed using diamond abrasive grains (Buhler, product name: Meta Diamond Suspension), followed by finish polishing with colloidal silica (Fujimi Incorporated, product name: COMPOL). .
(b) After the finish polishing, the surface other than the joint surface of the nozzle plate 300 with the laminated piezoelectric body 400 is masked with a resist or the like, and further, a sputtering apparatus (product name: CFS-4ES-231 manufactured by Shibaura Seisakusho Co., Ltd.) Then, sputtering is performed under the conditions of vacuum degree: 5.0 × 10 ⁻⁴ Pa, electric energy: 100 W, sputtering time: 18 minutes, and a titanium layer having a thickness of 0.03 to 0.06 μm is formed. On the titanium layer, a gold layer having a thickness of 1.0 μm under the conditions of vacuum degree: 5.0 × 10 ⁻⁴ Pa, electric energy: 200 W, sputtering time: 30 minutes using the same sputtering apparatus. Formed.
As a result, a metal layer (not shown) of a titanium-gold two-layer structure was coated over the entire joining surface of the nozzle plate 300.
(c) After the bonding surface of the nozzle plate 300 on which the metal layer is formed in the step (b) is brought into contact with the laminated piezoelectric body 400 in which the vibration plate 100 and the spacer 200 are laminated, and aligned. A printer head laminated body in which the nozzle plate 300 is bonded to the laminated piezoelectric body 400 was manufactured by thermocompression bonding under conditions of pressure: 10 to 100 MPa and temperature: 50 to 250 ° C. for about 1 minute or more.

  A printer head was manufactured in the same manner as in Example 1 except that the spacer was formed of a resin material (acrylic resin).

  A printer head was manufactured in the same manner as in Example 1 except that the spacer was formed of ceramics (aluminum nitride).

  A printer head was manufactured in the same manner as in Example 1 except that the spacer was formed of a metal material (SUS304).

  A printer head was manufactured in the same manner as in Example 1 except that the metal layer formed on the surfaces of the spacer, the vibration plate, and the nozzle plate joined to each other had a copper-copper two-layer structure.

Comparative Example 1

  A printer head was manufactured in the same manner as in Example 1 except that the diaphragm, spacer, and nozzle plate were bonded with an epoxy adhesive instead of gold / gold bonding.

The printer heads manufactured according to Examples 1 to 5 and Comparative Example 1 as described above were subjected to the following ink ejection test.
(1) using ink composed mainly of an ink jet test acid, ink containing solvent, and an ink mainly composed of alkali, 1 cycle: 300 [mu] m, the voltage application time: 30 .mu.s, voltage _V P-P: a 40V Each injection test was performed using a rectangular pulse. The results are shown in Table 1.
The number of injections until the injection speed decreased by 10% was compared, and the upper limit of the number of injections was set to 2 billion.

  From the above test results, each of Examples 1 to 5 according to the present invention has extremely excellent corrosion resistance and long-term reliability as compared with Comparative Example 1, and is suitable for various types of ink ejection. I found out.

  As described above, the present invention has excellent corrosion resistance and long-term reliability, and is particularly suitable for ejecting various types of inks such as acids, alcohols, organic solvents, and alkalis. An inkjet printer head is provided.

FIG. 3 is an exploded perspective view of a main part of the printer head according to the present invention. FIG. 2 is an exploded cross-sectional view of a main part of the printer head according to the present invention. FIG. 3 is a cross-sectional view of a main part of the printer head according to the present invention. The perspective view which shows the unit laminated body of the printer head concerning this invention The schematic perspective view which shows the state which laminated | stacked many unit laminated bodies shown in FIG. (a)-(c) is a figure which shows a part of process of manufacturing the diaphragm of the printer head concerning this invention. (a)-(d) is a figure which shows a part of process of manufacturing the spacer of the printer head concerning this invention. Schematic showing a nozzle plate of a printer head according to the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Piezoelectric element board 12 Ink supply port 14 Voltage application electrode 16 Power supply pad 18 Conductive layer pattern 20 Insulating protective layer 22 Joining metal layer 30 Plate-like silicon 32 Ink channel formation groove 33 Ink channel 34 Ink supply port 36 Power supply Pad accommodating portion 38 Metal layer 40 for bonding Plate-like silicon 42 Droplet injection hole 100 Diaphragm 200 Spacer 300 Nozzle plate 400 Multilayer piezoelectric body

Claims (6)

In an inkjet printer head configured to eject ink by the action of a diaphragm made of a piezoelectric body,
A plate-like spacer having a groove for forming an ink flow path and an opening for forming an ink supply path continuous therewith, and having a metal layer on at least the surface;
An insulating film that has an opening that communicates with the ink supply path forming opening of the spacer, and that is provided with an electrode corresponding to the groove for forming the ink flow path of the spacer on at least one surface, and the insulating film A diaphragm made of a piezoelectric body further provided with a metal layer;
A nozzle plate having an injection hole at a position corresponding to the ink flow path forming groove of the spacer and having a metal layer provided at a joint portion between the spacer and the vibration plate;
The vibration plate and the spacer are alternately laminated to form a laminated piezoelectric body in which an ink flow path and an ink supply path are formed, and the nozzle plate is disposed on the ink ejection side of the laminated piezoelectric body, and the vibration An ink jet printer head characterized in that a plate, a spacer, and a nozzle plate are bonded to each other through their metal layers. 2. The ink jet printer head according to claim 1, wherein the spacer is provided with a metal layer on an entire surface including a wall portion of the ink channel forming groove and an ink supply channel forming opening wall portion. The spacer, the ink jet printer head according to claim 1 or 2, characterized in that it is composed of a material consisting mainly Si or SiO _2. The ink jet printer head according to any one of claims 1 to 3, wherein the laminated piezoelectric body has a basic unit in which two diaphragms are sandwiched via a spacer. The ink jet printer head according to any one of claims 1 to 4, wherein the metal layer is made of the same metal. The ink jet printer head according to claim 5, wherein the metal layer is made of gold or copper.

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