JP2008229941A - Method for depositing liquid repellent film on nozzle plate, and manufacturing method for liquid droplet jetting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To deposit a liquid repellent film on a nozzle plate having a high wear-resistance. <P>SOLUTION: For an inkjet printer, five plates, an oscillating plate 30, and plates 10 to 13, which constitute a flow passage unit 4, are stacked and bonded. Then, a piezo-electric layer 31 is formed on the top surface of the oscillating plate 30. A heat treatment is applied to the piezo-electric layer 31 by heating the piezo-electric layer 31, the metal plate 30 and the plates 10 to 13 to a specified temperature (600 to 900°C) or higher under a lead atmosphere. At this time, the heat-treatment is simultaneously applied under the lead atmosphere, and a chrome oxide which is grown on a liquid droplet jetting surface 22 reacts with the lead in the atmosphere, so that the liquid repellent film 23 containing iron, chrome and lead is deposited. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for forming a liquid repellent film on a nozzle plate and a method for manufacturing a droplet ejecting apparatus.

  As a droplet ejecting apparatus that ejects droplets, for example, an inkjet head is known. In general, the ink jet head has a nozzle plate in which a plurality of fine nozzles for ejecting ink are formed at minute intervals.

  When ink adheres to the periphery of the droplet ejection surface of the nozzle plate in which the ejection ports of the plurality of nozzles are formed, the ink ejected after that causes surface tension or viscosity of the ink adhered to the droplet ejection surface. The injection trajectory may be bent and injected under the influence of the above. As a result, there is a problem in that ink cannot be ejected to a predetermined droplet ejection target position. Therefore, a liquid repellent film that prevents ink from adhering to the droplet ejection surface has been conventionally formed.

  As a method of forming a liquid repellent film on such a nozzle plate, Patent Document 1 discloses that a fluorine resin containing polytetrafluoroethylene (PTFE) or the like is applied to a nozzle plate made of a synthetic resin of polyimide. A method for forming a liquid film is known.

Japanese Patent Laid-Open No. 10-278278 (FIG. 1)

  By the way, an ink jet printer equipped with such an ink jet head is generally provided with a wiper made of an elastic member such as rubber, and the liquid droplet is ejected by rubbing (wiping) the droplet ejection surface with the wiper. It is configured to remove ink adhering to the ejection surface.

  However, since the liquid repellent film described in Patent Document 1 described above is made of a synthetic resin material, the wear resistance is low, and the liquid repellent film is worn away as wiping is repeated, resulting in a decrease in liquid repellency.

  Accordingly, an object of the present invention is to provide a method for forming a liquid-repellent film of a nozzle plate having high wear resistance and a method for manufacturing a droplet ejecting apparatus.

  The method for forming a liquid-repellent film on a nozzle plate according to the present invention is a method of forming a liquid-repellent film on a droplet ejection surface of a nozzle plate made of stainless steel having a plurality of nozzles, on which ejection ports of the plurality of nozzles are arranged. The nozzle plate is heated to a temperature higher than a predetermined crystal formation temperature in a lead atmosphere, so that the droplet ejection surface of the nozzle plate is made of a metal oxide crystal containing at least iron, chromium, and lead. A liquid repellent film is formed.

  In the method for forming a liquid repellent film for a nozzle plate according to the present invention, the nozzle plate is heated to a temperature higher than a predetermined crystal formation temperature in a lead atmosphere, whereby a metal oxide containing iron, chromium, and lead is formed on the droplet ejection surface. Crystals of the product are generated. By forming such a metal oxide liquid repellent film on the droplet ejection surface, the contact angle of the liquid on the droplet ejection surface is increased, and further, unevenness is generated by crystal growth. Increase is possible. That is, the liquid repellency of the droplet ejection surface is increased. Thus, since it is a liquid repellent film comprised by the metal oxide, compared with the liquid repellent film comprised by the resin material, the liquid repellent film excellent in abrasion resistance is obtained.

  At this time, in the present invention, the crystal formation temperature is preferably 600 to 900 ° C. As described above, by heating at 600 to 900 ° C. which is the crystal formation temperature, the crystal can be sufficiently grown and unevenness can be generated.

  In addition, a method for manufacturing a droplet ejecting apparatus according to the present invention includes a stainless steel nozzle plate having a plurality of nozzles, and a flow channel unit for manufacturing a channel unit having a liquid channel communicating with the plurality of nozzles. A path unit manufacturing process, and an actuator manufacturing process for manufacturing a piezoelectric actuator that is disposed on one surface of the flow path unit and applies an injection pressure to the liquid in the liquid flow path. A piezoelectric layer forming step of forming a piezoelectric layer made of a piezoelectric material containing a lead component so as to be integrated with the flow path unit; and a heat treatment step of heating the piezoelectric layer to a predetermined heat treatment temperature or more, In the heat treatment step, the integrated flow path unit and the piezoelectric layer are heated in a lead atmosphere, thereby simultaneously performing the heat treatment of the piezoelectric layer. The nozzle plate, the liquid droplet jetting surface in which ejecting ports are arranged in the plurality of nozzles, forming at least iron, chromium, and liquid-repellent film made of a crystalline metal oxide containing lead.

  According to the method for manufacturing a droplet ejecting apparatus of the present invention, the nozzle plate is heated to a temperature equal to or higher than a predetermined heat treatment temperature in a lead atmosphere, whereby a metal oxide containing iron, chromium, and lead is formed on the droplet ejecting surface. To produce crystals. By forming such a metal oxide liquid repellent film on the droplet ejection surface, the contact angle of the liquid on the droplet ejection surface is increased, and further, unevenness is generated by crystal growth. Increase is possible. That is, the liquid repellency of the droplet ejection surface is increased. Thus, since it is a liquid repellent film comprised by the metal oxide, compared with the liquid repellent film comprised by the resin material, the liquid repellent film excellent in abrasion resistance is obtained. Further, by heating in a lead atmosphere, the piezoelectric layer can be heat-treated while suppressing a decrease in the lead component of the piezoelectric material, and at the same time, a liquid repellent film can be formed on the nozzle plate.

  Further, in the flow channel unit manufacturing process, the nozzle plate and one or more metal plates forming the liquid flow channel are stacked, and the nozzle plate is pressurized while being heated to a predetermined bonding temperature or higher. And the metal plate are preferably joined by metal diffusion bonding. According to this configuration, the flow path unit can be easily manufactured by joining the nozzle plate and the metal plate by metal diffusion bonding.

  According to the present invention, the nozzle plate is heated to a predetermined crystal formation temperature or higher in a lead atmosphere, thereby generating a metal oxide crystal containing iron, chromium, and lead on the droplet ejection surface. By forming such a metal oxide liquid repellent film on the droplet ejection surface, the contact angle of the liquid on the droplet ejection surface is increased, and further, unevenness is generated by crystal growth. Increase is possible. That is, the liquid repellency of the droplet ejection surface is increased. Thus, since it is a liquid repellent film comprised by the metal oxide, compared with the liquid repellent film comprised by the resin material, the liquid repellent film excellent in abrasion resistance is obtained.

  An embodiment of the present invention will be described. In the present embodiment, an ink jet head (liquid droplet ejecting apparatus) that applies a jet pressure to ink and jets ink droplets from a nozzle onto a recording sheet by the jet pressure to record a desired image or character. It is an example which applied this invention to.

  First, an ink jet printer provided with the ink jet head of this embodiment will be briefly described. As shown in FIG. 1, an inkjet printer 100 includes a carriage 2 that can move in the left-right direction in FIG. 1, a serial type inkjet head 1 that is provided on the carriage 2 and that ejects ink onto recording paper P, A conveyance roller 3 for conveying the recording paper P forward in FIG. 1 is provided. The inkjet head 1 moves in the left-right direction (scanning direction) integrally with the carriage 2 and ejects ink onto the recording paper P from the nozzles 20 (see FIGS. 2 to 4) arranged on the lower surface thereof. Record the desired characters and images. Further, the recording paper P on which an image or the like is recorded by the ink jet head 1 is discharged forward (paper feeding direction) by the transport roller 3.

  Next, the inkjet head 1 will be described. As shown in FIGS. 2 to 4, the inkjet head 1 includes the pressure chamber 14, the flow path unit 4 in which the ink flow path 21 (liquid flow path) communicating with the nozzle 20 is formed, and the pressure chamber 14. And a piezoelectric actuator 5 that applies an ejection pressure to the ink.

  First, the flow path unit 4 will be described. As shown in FIG. 4, the flow path unit 4 includes a cavity plate 10, a base plate 11, a manifold plate 12, and a nozzle plate 13, and these four plates 10 to 13 are joined in a stacked state. These four plates 10 to 13 are stainless steel plates, and the ink flow paths 21 such as the nozzle 20, the pressure chamber 14, and the manifold 17 described later can be easily formed by etching. . On the surface of this stainless steel, the contained chromium is combined with oxygen to form a dense chromium oxide film, which is superior in corrosion resistance compared to other metal materials such as iron. Since the flow path unit 4 is always in contact with ink containing water as a main component, such a plate made of stainless steel having excellent corrosion resistance is preferably used.

  As shown in FIGS. 2 to 4, among the four plates 10 to 13, the uppermost cavity plate 10 has a plurality of pressure chambers 14 arranged along a plane passing through the cavity plate 10. The plurality of pressure chambers 14 are defined by partition walls 10a. The plurality of pressure chambers 14 are respectively covered with a diaphragm 30 and a base plate 11 described later from above and below. The plurality of pressure chambers 14 are arranged in two rows in the paper feeding direction (up and down direction in FIG. 2). Further, each pressure chamber 14 is formed in a substantially elliptical shape that is long in the scanning direction (left-right direction in FIG. 2) in plan view.

  As shown in FIGS. 3 and 4, communication holes 15 and 16 are formed at positions where the base plate 11 overlaps both end portions of the pressure chamber 14 in a plan view, respectively. The manifold plate 12 is formed with two manifolds 17 extending in the paper feeding direction so as to overlap with the communication hole 15 side portions of the pressure chambers 14 arranged in two rows in a plan view. These two manifolds 17 communicate with an ink supply port 18 (see FIG. 2) formed in a vibration plate 30 described later, and ink is supplied from an ink tank (not shown) to the manifold 17 via the ink supply port 18. The Furthermore, a plurality of communication holes 19 that are continuous with the plurality of communication holes 16 are also formed at positions where the manifold plate 12 overlaps the ends of the plurality of pressure chambers 14 opposite to the manifold 17 in plan view.

  Further, a plurality of nozzles 20 are formed at positions where the nozzle plate 13 respectively overlaps the plurality of communication holes 19 in plan view. As shown in FIG. 2, the plurality of nozzles 20 are arranged so as to overlap with the end portions on the opposite side of the manifold 17 of the plurality of pressure chambers 14 arranged in two rows along the paper feeding direction. The nozzle row is configured. As shown in FIG. 4, the lower surface of the nozzle plate 13 is a droplet ejection surface 22 on which ejection ports of a plurality of nozzles 20 are arranged.

  As shown in FIG. 4, the manifold 17 communicates with the pressure chamber 14 through the communication hole 15, and the pressure chamber 14 communicates with the nozzle 20 through the communication holes 16 and 19. As described above, a plurality of individual ink flow paths 21 extending from the manifold 17 to the nozzles 20 through the pressure chambers 14 are formed in the flow path unit 4.

  At this time, the ejection port of the nozzle 20 is disposed, and the droplet ejection surface 22 that ejects ink droplets from the ejection port is a main component of stainless steel so that the ink does not get wet and remains around the ejection port. A liquid repellent film 23 made of a metal oxide crystal containing lead in addition to iron and chromium is formed. This is because when ink remains around the ejection port of the droplet ejection surface 22, the ink ejected thereafter is affected by the surface tension or viscosity of the ink remaining around the ejection port of the droplet ejection surface 22. The jet trajectory is bent and jetted. Therefore, a liquid repellent film 23 is formed in order to prevent ink from remaining on the droplet ejection surface 22. The liquid repellent film 23 made of this metal oxide is superior in wear resistance as compared with the liquid repellent film made of a resin material.

  The liquid repellent film 23 is required to have a high liquid repellency so that the ink is wet and the ink does not remain on the droplet ejection surface 22. The liquid repellency is expressed by the contact angle of the droplet with respect to the droplet ejection surface 22. The contact angle is an angle θ shown in FIG. 5, and the larger the contact angle θ, the higher the liquid repellency. This contact angle θ is determined by the composition of the material constituting the liquid repellent film 23 on the droplet ejection surface 22. Further, when the contact angle θ is 90 degrees or more, the contact angle θ is further increased as the unevenness (surface roughness) of the droplet ejection surface 22 is increased. In other words, when the contact angle θ is less than 90 degrees, the contact angle θ decreases as the unevenness of the droplet ejection surface 22 increases.

  Next, the piezoelectric actuator 5 will be described. As shown in FIGS. 2 to 4, the piezoelectric actuator 5 includes a diaphragm 30 disposed on the upper surface of the cavity plate 10 having a plurality of pressure chambers 14, and straddles the piezoelectric chambers 14 on the upper surface of the diaphragm 30. And a plurality of individual electrodes 32 disposed on the upper surface of the piezoelectric layer 31.

  The diaphragm 30 is a substantially rectangular metal plate in plan view, and is made of, for example, an iron-based alloy such as stainless steel, a copper-based alloy, a nickel-based alloy, or a titanium-based alloy. The vibration plate 30 is joined to a partition wall portion 10 a disposed so as to surround the plurality of pressure chambers 14 while being disposed on the upper surface of the cavity plate 10 so as to cover the plurality of pressure chambers 14. Further, the upper surface of the vibration plate 30 made of metal and having conductivity also serves as a common electrode that sandwiches the piezoelectric layer 31 with the plurality of individual electrodes 32 and generates an electric field in the thickness direction in the piezoelectric layer 31. . Therefore, a common electrode is not required separately from the diaphragm 30, and the configuration of the piezoelectric actuator 5 is simplified correspondingly. Further, the diaphragm 30 as the common electrode is always held at the ground potential.

  On the upper surface of the vibration plate 30, a piezoelectric layer 31 made of a piezoelectric material mainly composed of lead zirconate titanate (PZT), which is a solid solution and is a ferroelectric substance, is formed of lead titanate and lead zirconate. Yes. The piezoelectric layer 31 is continuously formed so as to cover the plurality of pressure chambers 14.

  On the upper surface of the piezoelectric layer 31, a plurality of individual electrodes 32 having a substantially elliptical planar shape that is slightly smaller than the pressure chamber 14 are formed corresponding to the plurality of pressure chambers 14, respectively. These individual electrodes 32 are respectively arranged in a central portion (drive unit) away from the peripheral edge of the pressure chamber 14 in a region facing the corresponding pressure chamber 14. The individual electrode 32 is made of a conductive material such as gold, silver, palladium, platinum, or titanium.

  Further, a plurality of terminal portions 35 extend from the ends of the plurality of individual electrodes 32 arranged in two rows on the side of the communication hole 15 (outside in the left-right direction in FIG. 2) beyond the periphery of the pressure chamber 14. It is pulled out to the area. In addition, contacts of a flexible wiring member such as a flexible printed circuit (FPC) (not shown) are joined to the plurality of terminal portions 35, and the plurality of individual electrodes 32 include the wiring member and the plurality of terminals. The driver ICs (not shown) are electrically connected to each other through the terminal portion 35. When the piezoelectric actuator 5 is driven, a predetermined drive voltage is applied from the driver IC to the individual electrode 32 corresponding to the desired nozzle 20 that ejects ink.

  Next, the operation of the piezoelectric actuator 5 during ink ejection will be described. When a driving voltage is selectively applied from the driver IC to the plurality of individual electrodes 32, the individual electrodes 32 on the upper side of the piezoelectric layer 31 to which the driving voltage is applied and the lower side of the piezoelectric layer 31 held at the ground potential. Since the potentials of the diaphragm 30 serving as the common electrode are different from each other, an electric field in the thickness direction is generated in the piezoelectric layer 31 of the drive unit sandwiched between the individual electrode 32 and the diaphragm 30. When the polarization direction of the piezoelectric layer 31 is the same as the electric field direction, the piezoelectric layer 31 extends in the thickness direction, which is the polarization direction, and contracts in the horizontal direction. A region of the plate 30 facing the pressure chamber 14 is displaced toward the pressure chamber 14, and the diaphragm 30 is deformed so as to be convex toward the pressure chamber 14. At this time, since the volume of the pressure chamber 14 is reduced, an ejection pressure is applied to the ink inside the pressure chamber 14, and ink droplets are ejected from the nozzle 20 communicating with the pressure chamber 14.

  Next, a method for manufacturing the ink jet head 1 of the present embodiment will be described with reference to FIG. First, as shown in FIG. 6A, holes constituting the ink flow path 21 such as the nozzle 20, the pressure chamber 14, and the manifold 17 are formed in the metal plates 10 to 13 constituting the flow path unit 4. Since these plates 10 to 13 are made of a metal material, the holes constituting the ink flow path 21 can be easily formed by etching.

  Then, five plates of the diaphragm 30 and the plates 10 to 13 constituting the flow path unit 4 are stacked and joined (flow path unit manufacturing process). In this bonding step, for example, the five plates can be bonded by metal diffusion bonding by pressing the stacked plates while heating them to a predetermined temperature (for example, 1000 ° C.) or higher. Alternatively, the five plates may be joined with a ceramic adhesive having high heat resistance.

  Next, as shown in FIG. 6B, the piezoelectric layer 31 is formed on the upper surface of the vibration plate 30 so as to be integrated with the flow path unit 4 (piezoelectric layer forming step). Here, the piezoelectric layer 31 can be formed by an aerosol deposition method (AD method), a sputtering method, a chemical vapor deposition method (CVD method), a hydrogen synthesis method, or the like. For example, in the case of the AD method, the piezoelectric layer 31 can be formed by causing particles of a piezoelectric material such as PZT to collide with the upper surface of the vibration plate 30 at high speed and deposit them.

  By the way, when the piezoelectric layer 31 is formed by the AD method or the like, if the particles are refined or have lattice defects in the piezoelectric layer 31, the piezoelectric characteristics necessary for deforming the diaphragm 30 as it is. Cannot be obtained. Therefore, in such a case, the piezoelectric layer 31, the metal plate 30, and the plates 10 to 13 are used to improve the piezoelectric characteristics by growing the particle crystal of the piezoelectric material and repairing the lattice crystal in the crystal. The piezoelectric layer 31 is subjected to heat treatment (annealing) by heating to a predetermined annealing temperature or higher (600 to 900 ° C.).

  In this heat treatment, the diffusion of the lead component contained in the piezoelectric layer 31 is promoted, and the lead component contained in the piezoelectric layer 31 is reduced as it is. Therefore, by performing heat treatment of the piezoelectric layer 31 in a lead atmosphere, diffusion of the lead component contained in the piezoelectric layer 31 is prevented, and reduction of the lead component contained in the piezoelectric layer 31 is suppressed. For example, the laminated body of the piezoelectric layer 31 and the flow path unit 4 and the lead solid are accommodated in the same furnace and heated to perform heat treatment in a lead atmosphere.

  At the same time, the nozzle plate 13 of the flow path unit 4 together with the piezoelectric layer 31 is also housed in a furnace in a lead atmosphere and heated at 600 to 900 ° C. As a result, iron, chromium, oxygen, and the like contained in the stainless steel react with lead, and a liquid repellent film 23 made of a metal oxide crystal containing iron, chromium, and lead is formed on the droplet ejection surface 22. By adding a lead component to iron, chromium, oxygen, and the like contained in this stainless steel, the liquid repellency of the liquid repellent film 23 formed on the droplet ejection surface 22 is increased. Furthermore, by heating at 600 to 900 ° C., the crystal growth of the metal oxide is promoted and the unevenness of the droplet ejection surface 22 is increased, so that the liquid repellent film 23 formed on the droplet ejection surface 22 is repelled. Liquidity is further increased.

  Then, as shown in FIG. 6C, a plurality of individual electrodes 32 are formed in regions on the upper surface of the piezoelectric layer 31 that respectively overlap with the central portions of the plurality of pressure chambers 14. The plurality of individual electrodes 32 can be formed by screen printing, vapor deposition, sputtering, or the like.

  Next, in order to verify the effects of the present invention, specific examples and comparative examples will be described together. In the examples and comparative examples described below, the stainless steel is heated in a lead atmosphere at a heat treatment temperature of 850 ° C. for 15 minutes (Example) and the stainless steel is heated in an air atmosphere at a heat treatment temperature of 850 ° C. for 15 minutes. (Comparative example) and two samples were produced respectively. And contact angle (theta) in the case where pure water was made to adhere to the surface of the produced sample was measured 3 times. For stainless steel, SUS430 containing iron as a main component and containing 16 to 18% chromium and 0.6% or less nickel was used. Table 1 shows the contact angle θ measured from the manufactured samples of the example and the comparative example.

  As shown in Table 1, the contact angle on the surface of the sample of the example is larger than the contact angle on the surface of the sample of the comparative example.

  At this time, the image which image | photographed the surface of the sample of an Example and a comparative example with the electron microscope is shown to Fig.7 (a), (b). The size of the particles generated on the surface of the sample of the example (see FIG. 7A) is considerably larger than the size of the particles generated on the surface of the sample of the comparative example (see FIG. 7B). It has become. Further, the particles generated on the surfaces of the samples of this example and the comparative example were analyzed with an X-ray analyzer (not shown). As a result, as shown in FIG. 8A, the particles generated on the surface of the sample of the example are mainly composed of oxygen, lead, chromium and iron, and the particles generated on the surface of the sample of the comparative example are As shown in FIG. 8B, oxygen, chromium and iron are the main components.

  This is considered due to the following reasons. A lead component is added to iron, chromium, oxygen, and the like contained in stainless steel, and a metal oxide crystal containing iron, chromium, and lead is generated, thereby increasing the contact angle θ on the surface of the sample.

  Furthermore, by heating at 850 ° C., crystal growth of the metal oxide containing iron, chromium and lead was promoted, and the contact angle θ on the surface of the sample was further increased.

  Here, a lead component is added to iron, chromium, oxygen, etc. contained in stainless steel, and a metal oxide crystal containing iron, chromium, and lead is generated, thereby increasing the contact angle θ of the surface of the sample. This is also considered for the following reasons. When the contact angle θ is 90 degrees or more, the contact angle θ is further increased as the unevenness of the surface of the sample is increased. In other words, since the contact angle is less than 90 degrees on the surface of the metal oxide crystal that does not contain lead in the comparative example, the contact angle decreases when the surface roughness of the sample increases due to crystal growth. It should end up. However, on the surface of a sample made of a metal oxide crystal containing lead in the example, the contact angle increases as the surface roughness of the sample increases due to crystal growth. From this, lead components are added to iron, chromium, oxygen, etc. contained in stainless steel, and metal oxide crystals containing iron, chromium, and lead are generated, so that the contact angle θ is 90 ° C. or more, and heat treatment is performed. It can be considered that the contact angle is further increased by promoting crystal growth and increasing the irregularities on the surface of the sample.

  According to the method for forming the liquid repellent film of the nozzle plate 13 described above, the following effects can be obtained. By forming the liquid repellent film 23 made of a metal oxide containing iron, chromium and lead on the droplet ejection surface 22, the contact angle of the ink with respect to the droplet ejection surface 22 increases. Further, the crystal grows by the heat treatment, so that the particles become larger and the unevenness becomes rough, so that the contact angle can be further increased. That is, the liquid repellency of the droplet ejection surface 22 is increased. Thereby, compared with the liquid repellent film comprised with the resin material, the liquid repellent film excellent in abrasion resistance is obtained.

  In addition, according to the manufacturing method of the droplet ejecting apparatus of the present invention, the piezoelectric layer 31 is heat-treated while suppressing the reduction of the lead component of the piezoelectric material by heating in the lead atmosphere, and at the same time, the nozzle The liquid repellent film 23 of the plate 13 can also be formed.

  Furthermore, the flow path unit 4 can be easily manufactured by joining the nozzle plate 13 and the metal plates 10 to 12 by metal diffusion bonding.

Next, modified embodiments obtained by adding various modifications to the embodiment will be described. However, components having the same configuration as in the above embodiment are given the same reference numerals and description thereof is omitted as appropriate.
1] At the same time as annealing the piezoelectric layer, the liquid repellent film is not formed on the droplet ejection surface of the nozzle plate by the heat treatment temperature, but before the piezoelectric layer is formed, the droplet ejection surface is formed in a lead atmosphere. A step of heating the liquid repellent film to a temperature (600 ° C. to 900 ° C.) to form the liquid repellent film on the droplet ejection surface of the nozzle plate may be provided. Also, the annealing treatment of the piezoelectric layer is not always required, and depending on the method of forming the piezoelectric layer, the desired piezoelectric characteristics can be ensured, so that the annealing treatment may be unnecessary. In addition, the piezoelectric layer can be formed by bonding a piezoelectric sheet obtained by firing a green sheet made of a piezoelectric material to the diaphragm. In this case, heat treatment after bonding to the diaphragm is performed. Is unnecessary. Therefore, regardless of whether or not the piezoelectric layer is annealed, the liquid repellent film is heated to a temperature (600 ° C. to 900 ° C.) at which the liquid repellent film is formed on the droplet ejection surface of the nozzle plate in a lead atmosphere. You may perform the process to form separately.

1 is a schematic configuration diagram of an inkjet printer according to an embodiment. It is a top view of an inkjet head. FIG. 3 is a partially enlarged view of FIG. 2. It is the IV-IV sectional view taken on the line of FIG. It is explanatory drawing of the contact angle with respect to a plane. It is a figure which shows the first half process of the manufacturing method of an inkjet head, (a) shows a flow-path unit manufacturing process, (b) shows an actuator manufacture formation process, (c) shows an individual electrode formation process, respectively. It is an enlarged view of the surface particle | grains of a liquid ejection surface, (a) shows the particle | grains which have iron, chromium, and lead as a main component, (b) shows the particle | grains which have iron and chromium as a main component, respectively. It is a figure which shows the component contained in the surface particle | grains of a liquid injection surface, Comprising: The particle | grains which have iron, chromium, and a lead as a main component, (b) shows the particle | grains which have iron and chromium as a main component, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet head 4 Channel unit 5 Piezoelectric actuator 13 Nozzle plate 20 Nozzle 21 Channel unit 22 Droplet ejection surface 23 Liquid repellent film 31 Piezoelectric layer 100 Inkjet printer

Claims (4)

A method of forming a liquid repellent film on a droplet ejection surface of a nozzle plate made of stainless steel having a plurality of nozzles, on which ejection ports of the plurality of nozzles are arranged,
The nozzle plate is heated to a predetermined crystal formation temperature or higher in a lead atmosphere, whereby a liquid repellent made of a metal oxide crystal containing at least iron, chromium, and lead is formed on the droplet ejection surface of the nozzle plate. A method for forming a liquid repellent film on a nozzle plate, comprising forming a film.   The method for forming a liquid-repellent film on a nozzle plate according to claim 1, wherein the crystal generation temperature is 600 to 900 ° C. A flow path unit manufacturing process for manufacturing a flow path unit, including a nozzle plate made of stainless steel having a plurality of nozzles and having a liquid flow path communicating with the plurality of nozzles;
An actuator manufacturing step for manufacturing a piezoelectric actuator, which is disposed on one surface of the flow path unit and applies an injection pressure to the liquid in the liquid flow path,
The actuator manufacturing process includes:
A piezoelectric layer forming step of forming a piezoelectric layer made of a piezoelectric material containing a lead component so as to be integrated with the flow path unit;
A heat treatment step of heating the piezoelectric layer to a predetermined heat treatment temperature or higher,
In the heat treatment step, the flow path unit and the piezoelectric layer integrated with each other are heated in a lead atmosphere so that the piezoelectric layer is heat-treated, and at the same time, the nozzle nozzles of the nozzle nozzles A method of manufacturing a droplet ejecting apparatus, comprising: forming a liquid repellent film made of a metal oxide crystal containing at least iron, chromium, and lead on a droplet ejecting surface on which is disposed. In the flow path unit manufacturing step, the nozzle plate and one or more metal plates forming the liquid flow path are stacked and pressed while being heated to a predetermined bonding temperature or higher, whereby the nozzle plate and the The method for manufacturing a droplet ejecting apparatus according to claim 3, wherein the metal plate is joined by metal diffusion joining.