JP2007237717A - Method for manufacturing liquid droplet ejecting head and liquid droplet ejector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a droplet ejecting head capable of improving a yield by enhancing the adhesion between a diaphragm and a piezoelectric element, and to provide a droplet ejector. <P>SOLUTION: The method for manufacturing a droplet ejecting head comprises a diaphragm 55 which is formed a metal oxide layer 65 at least on one side of a surface, a lower electrode 4 arranged on the metal oxide layer 65 of the diaphragm 55, and a piezoelectric element 54 in which a piezoelectric layer 5 is pinched between the lower electrode 4 and a upper electrode 6. The surface of the metal oxide layer 65 is surface-treated for reduction and metalization. In addition, the lower electrode 4 is formed on the metal oxide layer 65 which is metalized by the surface treatment. Furthermore, the piezoelectric element 54 including the lower electrode 4 is formed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a droplet discharge head and a droplet discharge device.

  A droplet discharge method (inkjet method) has been proposed for image formation and microdevice manufacturing. This droplet discharge method is a method of forming a desired wiring pattern on a substrate by discharging a functional liquid containing a material for forming wirings in a semiconductor device into droplets from a droplet discharge head.

Such a droplet discharge head includes a nozzle that discharges ink droplets, a cavity that communicates with the nozzle, a diaphragm that forms a wall surface of the cavity, and a piezoelectric element that is formed on the diaphragm. And what drives the said piezoelectric element and displaces a diaphragm and discharges an ink drop from a nozzle is known (for example, refer patent document 1). The piezoelectric element has a structure in which a ferroelectric thin film made of a ferroelectric material such as lead zirconate titanate (PZT) is sandwiched between the lower electrode and the upper electrode and the pair of electrodes. . In general, a diaphragm of a droplet discharge head is configured by covering an elastic film made of silicon dioxide (SiO ₂ ) with a metal oxide such as zirconium oxide (ZrO ₂ ).

By the way, the lower electrode constituting the piezoelectric element has low adhesion with the metal oxide, and therefore, peeling easily occurs at the interface between the diaphragm and the piezoelectric element. In view of this, the adhesion between the diaphragm and the piezoelectric element is improved by providing Ti as an adhesion layer between the lower electrode constituting the piezoelectric element and the diaphragm.
JP 2006-19592 A

  However, even when the piezoelectric element is formed on the metal oxide through the adhesion layer made of Ti, peeling occurs at the interface between the metal oxide and the Ti layer during the interface manufacturing process, and the piezoelectric element is removed from the diaphragm. It is difficult to say that sufficient adhesion is obtained between the diaphragm and the piezoelectric element because the yield is lowered by peeling and the reliability of the completed droplet discharge head cannot be obtained.

  The present invention has been made in view of such circumstances, and provides a manufacturing method of a droplet discharge head and a droplet discharge device that can improve the yield by improving the adhesion between the diaphragm and the piezoelectric element. With the goal.

  The method for manufacturing a droplet discharge head according to the present invention includes a vibration plate in which a metal oxide layer is formed on at least one surface, a lower electrode provided on the metal oxide layer of the vibration plate, and the lower electrode. And a piezoelectric element in which a piezoelectric layer is sandwiched between an upper electrode and a top electrode, and a step of performing a surface treatment for reducing and metallizing the surface of the metal oxide layer in a method of manufacturing a droplet discharge head And a step of forming the lower electrode on the metal oxide layer metallized by the surface treatment, and a step of forming the piezoelectric element including the lower electrode.

  According to the method for manufacturing a droplet discharge head of the present invention, after the surface of the metal oxide layer is reduced and metallized by a surface treatment process, a lower electrode is formed on the metallized metal oxide layer. Since no metal oxide exists at the interface between the lower electrode and the diaphragm and the metals are in contact with each other, the adhesion between the lower electrode and the diaphragm can be improved. Therefore, the connection reliability at the interface between the lower electrode and the diaphragm is improved, so that peeling at the interface is prevented in the manufacturing process after the piezoelectric element is formed. Yield can be improved.

In the method of manufacturing a droplet discharge head, it is preferable that plasma treatment is performed as a surface treatment under a treatment gas atmosphere containing at least hydrogen on the surface of the metal oxide layer.
In this case, the surface of the metal oxide layer chemically reacts with hydrogen contained in the processing gas, whereby oxygen is reduced, and the surface of the metal oxide layer can be reliably metallized.

In the method of manufacturing a droplet discharge head, it is preferable that the surface treatment step and the lower electrode formation step are continuously performed in an inert atmosphere in the same treatment chamber.
In this way, since the surface treatment and the lower electrode formation process are continuously performed in an inert atmosphere under an inert atmosphere, the metallization is performed when the lower electrode is formed on the metal oxide layer. The surface of the metal oxide layer can be prevented from being exposed to the atmosphere. Therefore, adhesion of impurities to the metallized surface and contamination and oxidation of the surface are prevented, thereby preventing a decrease in adhesion at the interface between the lower electrode and the diaphragm, and connection reliability at the interface Can be further improved.

In the method of manufacturing a droplet discharge head, when the diaphragm is mainly composed of silicon oxide and the piezoelectric layer is formed of lead zirconate titanate, ZrO ₂ is used as the metal oxide. It is preferable to use it.

Here, when the diaphragm is composed mainly of silicon oxide, lead glass is generated when lead contained in lead zirconate titanate that can form the piezoelectric layer diffuses into the silicon oxide, and the diaphragm It becomes very brittle and causes a problem that the mechanical strength is reduced.
Therefore, if the present invention is adopted, lead contained in lead zirconate titanate is absorbed in ZrO ₂ (metal oxide film), so that the above-described problems due to lead diffusion can be prevented, and the droplet discharge head More reliable.

  A droplet discharge apparatus according to the present invention includes a droplet discharge head manufactured by the above-described method for manufacturing a droplet discharge head.

  According to the droplet discharge device of the present invention, since the droplet discharge head 50 having high adhesion between the diaphragm and the piezoelectric element is provided as described above, the droplet discharge device itself has a discharge performance. Good, high performance and high reliability.

Hereinafter, an embodiment of the present invention will be described. In the following description, various structures are illustrated using drawings, but the structures shown in these drawings may be shown with different dimensions from the actual structures in order to show the characteristic parts in an easy-to-understand manner. is there.
First, an ink jet recording head (droplet discharge head) obtained by this manufacturing method will be described prior to the method of manufacturing a droplet discharge head according to the present embodiment.

(Configuration of droplet discharge head)
1 is an exploded perspective view of a droplet discharge head, FIG. 2 is a side sectional view showing a schematic configuration of the droplet discharge head, and FIG. 3 shows a configuration of a piezoelectric element in the droplet discharge head. It is an enlarged view shown. Note that FIG. 1 is shown upside down from a normally used state. In these drawings, reference numeral 50 denotes a droplet discharge head (hereinafter referred to as a head). As shown in FIG. 1, the head 50 includes a head main body and a piezoelectric element 54 provided on the head main body. The head 50 is used as a so-called ink jet recording head, and is used in an ink jet printer which is an embodiment of a droplet discharge device described later.

  That is, the head 50 includes a nozzle plate 51, an ink chamber substrate 52, a vibration plate 55, and a piezoelectric element 54 bonded to the vibration plate 55 as shown in FIG. It is housed and configured. The base 56 is formed of, for example, various resin materials, various metal materials, and the like, and the ink chamber substrate 52 is fixed and supported on the base 56 as shown in FIG.

  As shown in FIGS. 1 and 2, a plurality of cavities (ink cavities) 521 and ink are formed from side walls (partition walls) 522, nozzle plates 51, and vibration plates 55 formed by patterning the ink chamber substrate 52. A reservoir 523 that temporarily stores ink supplied from a cartridge (not shown) and a supply port 524 that supplies ink from the reservoir 523 to each cavity 521 are partitioned.

  Further, as a base material (substrate) constituting the ink chamber substrate 52, a silicon single crystal substrate having a plane orientation (110) is used as will be described later. In addition, since such a plane orientation enables easy and reliable anisotropic etching, the workability and reliability of the reservoir 523 and each of the cavities 521 are high.

As shown in FIG. 3, the piezoelectric element 54 has a structure in which a piezoelectric layer 5 made of lead zirconate titanate (PZT) is sandwiched between a lower electrode 4 and an upper electrode 6.
The lower electrode 4 is formed by sequentially stacking platinum (Pt) and iridium (Ir), and the upper electrode 6 is made of a conductive material such as platinum (Pt), iridium (Ir), aluminum ( Al) or the like can be employed, and iridium is used in this embodiment.

The diaphragm 55 has a configuration in which a metal oxide layer is formed on at least one surface. Specifically, in the present embodiment, the diaphragm 55 is provided on the elastic film 45 made of silicon dioxide (SiO ₂ ) having a thickness of about 1.0 μm, and has a thickness of about 0.00 mm. A metal oxide layer 65 made of 4 μm zirconium oxide (ZrO ₂ ) is laminated. The metal oxide layer 65 functions as an insulator film.

  The diaphragm 55 is disposed on one surface of the ink chamber substrate 52. In addition, a plurality of piezoelectric elements 54 are provided on the diaphragm 55. By the way, the surface of the diaphragm 55 is subjected to a surface treatment which will be described later, whereby the adhesion between the diaphragm 55 and the lower electrode 4 is enhanced. As the surface treatment, a Zr layer is exposed on the surface of the diaphragm 55 by performing plasma treatment on the surface of the diaphragm 55 using a processing gas containing at least hydrogen.

The lower electrode 4 is formed on the diaphragm 55 subjected to such surface treatment. Here, the lower electrode 4 is formed by laminating a Pt layer and an Ir layer as described above. That is, Zr and Pt are laminated at the interface between the lower electrode 4 and the diaphragm 55. Therefore, no metal oxide (ZrO ₂ ) is present at the interface, and the metals are laminated, so that high adhesion can be obtained between the diaphragm 55 and the lower electrode 4. Therefore, peeling of the piezoelectric element 54 from the vibration plate 55 is prevented, so that the reliability of the droplet discharge head 50 itself is high.

  Each piezoelectric element 54 is disposed corresponding to a substantially central portion of each cavity 521. Each of the piezoelectric elements 54 is electrically connected to a piezoelectric element drive circuit described later, and is configured to operate (vibrate, deform) based on a signal from the piezoelectric element drive circuit. That is, each piezoelectric element 54 functions as a vibration source (head actuator), and the diaphragm 55 vibrates (deflects) due to the vibration (deflection) of the piezoelectric element 54, and the internal pressure of the cavity 521. It functions to raise the momentary.

  Further, a communication hole 531 is formed at a predetermined position of the diaphragm 55 so as to penetrate in the thickness direction of the diaphragm 55 as shown in FIG. The communication holes 531 supply ink from an ink cartridge described later to the reservoir 523.

  The nozzle plate 51 is composed of, for example, a stainless steel rolling plate or the like, and has a large number of nozzles 511 for ejecting ink droplets formed in a line. The pitch between these nozzles 511 is appropriately set according to the printing accuracy.

  The cavities 521 are disposed corresponding to the nozzles 511 as shown in FIG. 1, and the volumes of the cavities 521 are variable by the vibration of the diaphragm 55. Ink droplets are discharged from 511.

  The average thickness of the ink chamber substrate 52, that is, the thickness including the cavity 521 is not particularly limited, but is preferably about 10 to 1000 μm, and more preferably about 100 to 500 μm. Further, the volume of the cavity 521 is not particularly limited, but is preferably about 0.1 to 100 nL, and more preferably about 0.1 to 10 nL.

Next, a case where ink droplets are ejected from the head 50 having such a configuration will be described.
The head 50 is in a state where a predetermined ejection signal is not input via the piezoelectric element driving circuit, that is, in a state where no voltage is applied between the lower electrode 4 and the upper electrode 6 of the piezoelectric element 54. Deformation does not occur in the piezoelectric layer 5. For this reason, the diaphragm 55 is not deformed, and the cavity 521 is not changed in volume. Accordingly, no ink droplet is ejected from the nozzle 511.

  On the other hand, a state in which a predetermined ejection signal is input through the piezoelectric element drive circuit, that is, a state in which a constant voltage (for example, about 30 V) is applied between the lower electrode 4 and the upper electrode 6 of the piezoelectric element 54. Then, the piezoelectric layer 5 is bent and deformed in the minor axis direction. Thereby, the diaphragm 55 bends, for example, about 500 nm, and the volume change of the cavity 521 occurs. At this time, the pressure in the cavity 521 increases instantaneously, and ink droplets can be ejected from the nozzle 511.

  That is, when a voltage is applied, the crystal lattice of the piezoelectric layer 5 is stretched in a direction perpendicular to the plane, but is simultaneously compressed in a direction parallel to the plane. In this state, a tensile stress is applied to the piezoelectric layer 5 in the plane. Therefore, the diaphragm 55 is deflected and bent by this stress. The larger the displacement amount (absolute value) of the piezoelectric layer 5 in the minor axis direction of the cavity 521, the larger the deflection amount of the vibration plate 55, and more efficiently eject ink droplets. Here, “efficient” means that the same amount of ink droplets can be ejected with a smaller voltage.

When the ejection of one ink is completed in this way, the piezoelectric element drive circuit stops applying the voltage between the lower electrode 4 and the upper electrode 6. As a result, the piezoelectric element 54 returns to its original shape, and the volume of the cavity 521 increases. At this time, the pressure (pressure in the positive direction) from the ink cartridge 631 described later toward the nozzle 511 is applied to the ink. For this reason, air is prevented from entering the ink chamber 521 from the nozzle 511, and an amount of ink corresponding to the ink discharge amount is supplied from the ink cartridge 631 to the cavity 521 through the reservoir 523. According to the droplet discharge head 50, since the adhesiveness between the piezoelectric element 54 and the diaphragm 55 is high and difficult to peel off, the above-described ink discharge can be performed over a long period of time. .
In this way, arbitrary (desired) characters, figures, and the like can be obtained by sequentially inputting ejection signals to the piezoelectric elements 54 at positions where ink droplets are to be ejected via the piezoelectric element drive circuit. Can be printed.

(Method for manufacturing droplet discharge head)
Subsequently, as an embodiment of the method for manufacturing a droplet discharge head according to the present invention, a process for manufacturing the droplet discharge head 50 will be described with reference to the drawings.
First, the base material to be the ink chamber substrate 52, that is, the substrate 2 made of the above-described (110) -oriented silicon single crystal substrate (Si substrate) is prepared. Then, as shown in FIG. 4A, the diaphragm 55 is bonded onto the substrate 2. As described above, the diaphragm 55 is formed by laminating the elastic film 45 made of silicon dioxide and the metal oxide layer 65 made of zirconium oxide. In addition, the elastic film 45 side of the diaphragm 55 is bonded to the substrate 2.

Subsequently, a surface treatment is performed on the surface of the diaphragm 55 opposite to the surface bonded to the substrate 2, that is, the metal oxide layer 65. Specifically, in the present embodiment, as the surface treatment, the diaphragm 55 is subjected to plasma treatment in an atmosphere using argon (Ar) added with hydrogen (H ₂ ) as a treatment gas.

At this time, the hydrogen _{(H 2)} is a process gas of the plasma treatment, the metal oxide layer reduction reaction comprised the metal oxide layer 65 from the ZrO ₂ occurs oxygen from the _{(ZrO 2) 55 (O 2} ) Is reduced. Therefore, the treated surface 55a subjected to the plasma treatment is in a state where ZrO ₂ is metallized and Zr is exposed.

Next, the piezoelectric element 54 is formed on the diaphragm 55.
First, as shown in FIG. 4B, the lower electrode 4 is formed on the metal oxide layer 65 metallized by the plasma treatment. Specifically, the precursor layer 4A of the lower electrode 4 is formed on the diaphragm 55 subjected to such plasma treatment by a known method such as sputtering. Since the lower electrode 4 is formed by laminating the Pt layer 4a and the Ir layer 4b, the Pt layer 4a is laminated on the processing surface 55a. At this time, since the Zr layer 65a is exposed on the processing surface 55a, metals (Zr and Pt) are laminated at the interface between the lower electrode 4 and the metal oxide layer 65. ing. Thus, the adhesion between the diaphragm 55 and the lower electrode 4 can be improved by stacking metals without the presence of metal oxide (ZrO ₂ ) at the interface.

  The step of forming the precursor layer 4A of the lower electrode 4 is desirably performed continuously in an inert atmosphere in a chamber (processing chamber) in which the above-described plasma processing (surface processing) is performed. In this way, it is possible to prevent the processing surface 55a from being exposed to the atmosphere, and thus it is possible to prevent the adhesion with the Pt layer from being deteriorated due to contamination, oxidation, adhesion of impurities, or the like of the processing surface 55a.

Hereinafter, a process of forming the piezoelectric element 54 including the lower electrode 4 will be described.
As shown in FIG. 4C, a precursor layer 5A of a piezoelectric layer 5 made of lead zirconate titanate (PZT) is formed on the precursor layer 4A of the lower electrode 4. Here, in the present embodiment, a so-called MOD (Metal-Organic Decomposition) method for obtaining a precursor layer 5A made of a metal oxide by applying and drying a solution in which a metal organic substance is dissolved, and further baking it at a high temperature. 5A is used to form the precursor layer 5A. Note that Ti may be provided as an adhesion layer between the lower electrode 4 and the piezoelectric layer 5. Moreover, the manufacturing method of the piezoelectric layer 70 is not limited to the MOD method described above, and for example, a sol-gel method or the like may be used.

  In addition, as a material of the piezoelectric layer 70, besides a ferroelectric piezoelectric material such as lead zirconate titanate, a relaxor ferroelectric material in which a metal such as niobium, nickel, magnesium, bismuth, or ytterbium is added thereto, or the like. It may be used.

Subsequently, the precursor layer 6A of the upper electrode 6 is formed on the precursor layer 5A of the piezoelectric layer 5 by a known method such as a sputtering method in the same manner as the precursor layer 4A of the lower electrode 4.
As the precursor layer 6A, a conductive material such as platinum (Pt), iridium (Ir), aluminum (Al), or the like can be used. Note that when aluminum is used, iridium or the like is laminated thereon to prevent electric corrosion.
Through the above steps, a laminated body 54 a constituting the piezoelectric element 54 is formed on the diaphragm 55.

  Thereafter, the laminated body 54a is patterned so as to correspond to the individual cavities 521 to be formed, so that the number of piezoelectric elements 54 corresponding to the number of cavities 521 shown in FIG. 1 is formed.

  Next, the substrate 2 serving as a base material to be the ink chamber substrate 52 is patterned, and recesses to be the cavities 521 are formed at positions corresponding to the piezoelectric elements 54, and recesses to be the reservoir 523 and the supply port 524 at predetermined positions. Form. In this embodiment, the substrate 2 constituting the ink chamber substrate 52 is made of, for example, a silicon single crystal having a plane orientation (110). Since the substrate 2 having such a plane orientation (110) is suitable for anisotropic etching, the ink chamber substrate 52 can be formed easily and reliably.

  Specifically, a mask layer is formed in accordance with the position where the cavity 521, the reservoir 523 and the supply port 524 are to be formed. For example, a high amount of potassium hydroxide, tetramethylammonium hydroxide, etc. Wet etching is performed with a concentrated aqueous alkali solution.

  In this way, the ink chamber substrate 52 can be formed by etching and removing the substrate 2 in the thickness direction until the vibration plate 55 is exposed. At this time, the portion left unetched becomes the side wall 522. The method for patterning the substrate 2 is not limited to the wet etching described above. For example, parallel plate type reactive ion etching, inductive coupling type, electron cyclotron resonance type, helicon wave excitation type, magnetron type Also, dry etching such as a plasma etching method or an ion beam etching method can be employed.

Next, the nozzle plate 51 on which the plurality of nozzles 511 are formed is joined in a state in which the nozzles 511 are aligned so as to correspond to the recesses that serve as the cavities 521. Thereby, a plurality of cavities 521, a reservoir 523, and a plurality of supply ports 524 are formed. For the bonding of the nozzle plate 51, for example, an adhesive method using an adhesive or a fusion method can be used.
Thereafter, the ink chamber substrate 52 is attached to the substrate 56, whereby the droplet discharge head 50 is manufactured.

In the above embodiment, the separately prepared diaphragm 55 is bonded to the substrate 2. However, for example, the diaphragm may be formed integrally with the substrate 2. In this case, the silicon substrate is thermally oxidized to form a silicon dioxide (SiO ₂ ) layer functioning as the elastic film 45, and zirconium oxide (ZrO ₂ ) is formed as a metal oxide layer on the silicon dioxide layer. Form. Then, similarly to the above embodiment, etching is performed so as to expose the elastic film 45 from the back surface (the surface on which the silicon dioxide layer is not formed) of the substrate 2, thereby forming a cavity 521 and a reservoir 523, and vibration. The plate can be formed integrally with the substrate 2.

According to such a manufacturing method of the droplet discharge head 50, as described above, the plasma treatment is performed on the metal oxide layer 65 made of ZrO _{2 in the} atmosphere of the processing gas containing hydrogen, so that the surface is reduced and the metal is reduced. As a result, the Zr layer 65a is exposed. Since the Pt layer constituting the lower electrode 4 is laminated on the Zr layer 65a, the metals (Pt and Zr) are in contact with each other at the interface between the lower electrode 4 and the metal oxide layer 65. High adhesion can be obtained. Therefore, the connection reliability between the lower electrode 4 and the diaphragm 55 is improved, and peeling that occurs at the interface during the manufacturing process of the droplet discharge head 50 can be prevented, and as a result, the yield can be improved.

In the above-described method for improving the adhesion between the diaphragm 55 and the lower electrode 4, at least one surface side is plated on a base substrate formed of a metal oxide such as SiO ₂ or TiO _2. It can also be applied to cases.
Specifically, as a pretreatment for the plating treatment, plasma treatment is performed on the surface of the metal oxide layer in the base substrate using the above-described argon to which hydrogen is added as a treatment gas. By such plasma treatment, the surface of the metal oxide layer can be metallized. Subsequently, a plating process is performed on the surface of the base substrate on which the plasma process has been performed. In this way, plating is formed on the surface metallized by the plasma treatment, so that the adhesion between the base substrate and the plating film can be improved.

  Alternatively, the above plasma treatment is performed on the base substrate made of a metal material, thereby removing the metal oxide film and impurities formed on the surface, and exposing the metal surface on the surface of the base substrate. Subsequently, a plating process is performed on the surface of the base substrate on which the plasma process has been performed. In this way, plating can be formed on the metal material exposed on the surface by the plasma treatment, so that the adhesion between the base substrate and the plating film can be improved.

(Droplet discharge device)
Next, an ink jet printer as an embodiment of a droplet discharge device including the droplet discharge head 50 will be described. The ink jet printer includes not only those that print on paper or the like but also industrially used droplet discharge devices.

FIG. 5 is a schematic configuration diagram of the ink jet printer. Reference numeral 60 in FIG. 5 denotes an ink jet printer. In the following description, the upper side in FIG. 5 is referred to as “upper part” and the lower side is referred to as “lower part”.
The ink jet printer 60 includes an apparatus main body 620. The ink jet printer 60 has a tray 621 for placing the recording paper P on the upper rear side, a discharge port 622 for discharging the recording paper P on the lower front side, and an operation panel on the upper surface. 670.

The operation panel 670 is composed of, for example, a liquid crystal display, an organic EL display, an LED lamp, and the like. A display unit (not shown) for displaying an error message and the like, and an operation unit (not shown) including various switches and the like. Z)).
Inside the apparatus main body 620, there are mainly a printing apparatus 640 provided with a reciprocating head unit 630, a paper feeding apparatus 650 for feeding the recording paper P one by one to the printing apparatus 640, the printing apparatus 640 and the paper feeding apparatus. A control unit 660 for controlling the 650 is provided.

  Under the control of the control unit 660, the paper feeding device 650 intermittently feeds the recording paper P one by one. The recording paper P that is intermittently fed passes near the lower portion of the head unit 630. At this time, the head unit 630 reciprocates in a direction substantially perpendicular to the feeding direction of the recording paper P, and printing on the recording paper P is performed. That is, the reciprocation of the head unit 630 and the intermittent feeding of the recording paper P are the main scanning and the sub-scanning in printing, and ink jet printing is performed.

The printing apparatus 640 includes a head unit 630, a carriage motor 641 serving as a drive source for the head unit 630, and a reciprocating mechanism 642 that reciprocates the head unit 630 in response to the rotation of the carriage motor 641. .
The head unit 630 includes the droplet discharge head 50 including a large number of nozzles 511, an ink cartridge 631 that supplies ink to the droplet discharge head 50, and the droplet discharge head 50 and the ink cartridge 631. A carriage 632.

  Note that full-color printing can be performed by using an ink cartridge 631 filled with ink of four colors of yellow, cyan, magenta, and black (black). In this case, the head unit 630 is provided with the droplet discharge heads 50 corresponding to the respective colors.

The reciprocating mechanism 642 includes a carriage guide shaft 643 whose both ends are supported by a frame (not shown), and a timing belt 644 extending in parallel with the carriage guide shaft 643.
The carriage 632 is supported by the carriage guide shaft 643 so as to be able to reciprocate and is fixed to a part of the timing belt 644.
When the timing belt 644 travels forward and backward through a pulley by the operation of the carriage motor 641, the head unit 630 reciprocates while being guided by the carriage guide shaft 643. During this reciprocation, ink is appropriately discharged from the droplet discharge head 50 and printing on the recording paper P is performed.

The sheet feeding device 650 includes a sheet feeding motor 651 as a driving source and a sheet feeding roller 652 that rotates by the operation of the sheet feeding motor 651.
The paper feed roller 652 is composed of a driven roller 652a and a drive roller 652b that are vertically opposed to each other with a feeding path (recording paper P) of the recording paper P interposed therebetween. The drive roller 652b is a paper feed motor 651. It is connected to. With such a configuration, the paper feed roller 652 can feed a large number of recording sheets P installed on the tray 621 one by one toward the printing apparatus 640. Instead of the tray 621, a configuration in which a paper feed cassette that stores the recording paper P can be detachably mounted may be employed.

The control unit 660 performs printing by controlling the printing device 640, the paper feeding device 650, and the like based on print data input from a host computer such as a personal computer or a digital camera.
Although not shown in the figure, the control unit 660 mainly includes a memory that stores a control program for controlling each unit, a piezoelectric element drive that drives a piezoelectric element (vibration source) 54 to control ink ejection timing. A circuit for driving the print device 640 (carriage motor 641), a drive circuit for driving the paper feed device 650 (paper feed motor 651), a communication circuit for obtaining print data from the host computer, And a CPU that performs various controls in each unit.

In addition, for example, various sensors that can detect the printing environment such as the remaining amount of ink in the ink cartridge 631, the position of the head unit 630, temperature, and humidity are electrically connected to the CPU.
The control unit 660 obtains print data via the communication circuit and stores it in the memory. The CPU processes the print data and outputs a drive signal to each drive circuit based on the process data and input data from various sensors. The piezoelectric element 54, the printing device 640, and the paper feeding device 650 are operated by this drive signal. Thus, desired printing is performed on the recording paper P.

In such an ink jet printer 60, as described above, since the adhesiveness between the vibration plate 55 and the piezoelectric element 54 is high and the droplet discharge head 50 is provided with high reliability, the ink jet printer itself is also provided. High performance and high reliability with good discharge performance.
Note that the ink jet printer of the present invention can also be a droplet discharge device used industrially as described above. In this case, as the ink (liquid material) to be ejected, various functional materials are adjusted to an appropriate viscosity with a solvent or a dispersion medium and used.

It is a disassembled perspective view of a droplet discharge head. It is a sectional side view showing a schematic structure of a droplet discharge head. It is an enlarged view showing a configuration of a piezoelectric element in a droplet discharge head. It is a figure explaining the process of manufacturing a droplet discharge head. It is a schematic block diagram of an inkjet printer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 4 ... Lower electrode, 5 ... Piezoelectric layer, 6 ... Upper electrode, 50 ... Droplet discharge head, 54 ... Piezoelectric element, 50 ... Droplet discharge head, 55 ... Vibration plate, 60 ... Inkjet printer (droplet discharge device) ), 65 ... Metal oxide layer

Claims (5)

A diaphragm having a metal oxide layer formed on at least one surface thereof, a lower electrode provided on the metal oxide layer of the diaphragm, and a piezoelectric layer sandwiched between the lower electrode and the upper electrode In a manufacturing method of a droplet discharge head comprising:
A step of performing a surface treatment for reducing and metallizing the surface of the metal oxide layer, a step of forming the lower electrode on the metal oxide layer metallized by the surface treatment, and the lower electrode And a step of forming the piezoelectric element. A method of manufacturing a droplet discharge head, comprising:   2. The method of manufacturing a droplet discharge head according to claim 1, wherein plasma treatment is performed as a surface treatment in a treatment gas atmosphere containing at least hydrogen on the surface of the metal oxide layer.   3. The method of manufacturing a droplet discharge head according to claim 1, wherein the step of performing the surface treatment and the step of forming the lower electrode are continuously performed under an inert atmosphere in the same processing chamber. Method. 4. The method according to claim 1, wherein when the diaphragm is composed mainly of silicon oxide and the piezoelectric layer is formed of lead zirconate titanate, ZrO ₂ is used as the metal oxide. A method for manufacturing a droplet discharge head according to claim 1. A droplet discharge apparatus comprising the droplet discharge head manufactured by the method for manufacturing a droplet discharge head according to claim 1.

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