JP2001260356A - Actuator device, manufacturing method therefor, ink-jet type recording head and ink-jet type recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an actuator device, a manufacturing method therefor, an ink-jet type recording head and an ink-jet type recording apparatus in which a breakdown of piezoelectric elements is prevented. SOLUTION: This actuator device includes piezoelectric elements 300 each comprising a lower electrode 60 set via an insulating layer 50 to the side of one face of a substrate 10 where cavities 12 are defined, a piezoelectric layer 70 set on the lower electrode 60 and an upper electrode 80 set to a front face of the piezoelectric layer 70. A concentration of an alkali metal or an alkaline earth metal element present at least at a surface layer of a region of an outer peripheral face of the piezoelectric element 300 where the piezoelectric layer 70 is exposed is set to be 1×1011 atoms/cm2 or smaller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator device having a piezoelectric element for displacing a piezoelectric material layer by applying a voltage thereto, and a method of manufacturing the same. The present invention relates to an ink jet recording head and an ink jet recording apparatus in which a part of a chamber is constituted by a vibration plate, a piezoelectric element is formed on the surface of the vibration plate, and ink droplets are ejected by displacement of the piezoelectric element.

[0002]

2. Description of the Related Art A part of a pressure generating chamber communicating with a nozzle opening for discharging ink droplets is constituted by a vibrating plate, and the vibrating plate is deformed by a piezoelectric element to pressurize the ink in the pressure generating chamber to pass the nozzle opening. Two types of ink jet recording heads that eject ink droplets have been put into practical use, one using a longitudinal vibration mode piezoelectric actuator in which a piezoelectric element expands and contracts in the axial direction, and the other using a flexural vibration mode piezoelectric actuator. ing.

In the former method, the volume of the pressure generating chamber can be changed by bringing the end face of the piezoelectric element into contact with the diaphragm, so that a head suitable for high-density printing can be manufactured. There is a problem in that a difficult process of cutting into a comb shape in accordance with the arrangement pitch of the openings and an operation of positioning and fixing the cut piezoelectric element in the pressure generating chamber are required, and the manufacturing process is complicated.

On the other hand, in the latter, a piezoelectric element can be formed on a diaphragm by a relatively simple process of sticking a green sheet of a piezoelectric material according to the shape of a pressure generating chamber and firing the green sheet. In addition, there is a problem that a certain area is required due to the use of flexural vibration, and that high-density arrangement is difficult.

On the other hand, in order to solve the latter disadvantage of the recording head, a uniform piezoelectric material layer is formed by a film forming technique over the entire surface of the diaphragm as disclosed in Japanese Patent Application Laid-Open No. 5-286131. A proposal has been made in which the piezoelectric material layer is cut into a shape corresponding to the pressure generating chambers by a lithography method, and a piezoelectric element is formed so as to be independent for each pressure generating chamber.

This eliminates the need for attaching the piezoelectric element to the vibration plate, which not only allows the piezoelectric element to be manufactured by a precise and simple method such as lithography, but also reduces the thickness of the piezoelectric element. There is an advantage that it can be made thin and can be driven at high speed.

[0007]

However, a piezoelectric element manufactured by such a thin film technique and a lithography method has a problem that dielectric breakdown occurs when a voltage is applied to the piezoelectric element and driving is repeated. This dielectric breakdown
This is likely to occur at the boundary between the piezoelectric layer and the upper electrode film or the lower electrode film, particularly in a region facing the vicinity of the end of the pressure generating chamber.

[0008] Such a problem exists not only in an ink jet recording head but also in an actuator device having a piezoelectric element on one side of a substrate via a diaphragm.

In view of such circumstances, it is an object of the present invention to provide an actuator device that prevents dielectric breakdown of a piezoelectric element, a method of manufacturing the same, and an ink jet recording head and an ink jet recording device.

[0010]

According to a first aspect of the present invention, there is provided a lower electrode provided with an insulating layer on one side of a substrate defining a cavity, and a lower electrode provided on the lower electrode. In an actuator device including a provided piezoelectric layer and a piezoelectric element including an upper electrode provided on the surface of the piezoelectric layer, at least a surface layer of a peripheral surface of the piezoelectric element where the piezoelectric layer is exposed is provided. Each concentration of the alkali metal or alkaline earth metal element present is 1 × 10 ¹¹ a
The present invention provides an actuator device characterized in that the ratio is not more than toms / cm ² .

In the first aspect, since the concentration of the alkali metal or alkaline earth metal element contained in the piezoelectric layer is sufficiently suppressed, dielectric breakdown of the piezoelectric layer is prevented.

A second aspect of the present invention is the actuator device according to the first aspect, wherein the alkali metal or alkaline earth metal element is selected from the group consisting of sodium, potassium, magnesium and calcium. It is in.

In the second aspect, the dielectric breakdown of the piezoelectric layer is more reliably prevented by suppressing the concentration of the specific metal element existing in the surface layer of the piezoelectric layer.

A third aspect of the present invention is the actuator device according to the first or second aspect, wherein the cavity is formed by etching the substrate with an alkaline solution.

According to the third aspect, the cavity can be formed relatively easily and with high precision.

In a fourth aspect of the present invention, the first or second
In the above aspect, the cavity may be removed by an organic etching solution.

According to the fourth aspect, the pressure generating chamber can be formed while the concentration of the predetermined metal contained in the piezoelectric layer is relatively easily and reliably reduced.

According to a fifth aspect of the present invention, a nozzle forming member having a nozzle opening communicating with the cavity is joined to the other surface of the substrate constituting the actuator device according to any one of the first to fourth aspects. The ink jet recording head is characterized in that:

According to the fifth aspect, it is possible to realize an ink jet type recording head capable of performing good ink ejection from the nozzle opening by driving the piezoelectric element.

According to a sixth aspect of the present invention, in the fifth aspect, the cavity is formed in a silicon single crystal substrate by anisotropic etching, and each layer of the piezoelectric element is formed by film formation and lithography. An ink jet recording head is characterized in that:

In the sixth aspect, an ink jet recording head having high-density nozzle openings can be manufactured in a large amount and relatively easily.

According to a seventh aspect of the present invention, there is provided an ink jet recording apparatus comprising the ink jet recording head according to the fifth or sixth aspect.

According to the seventh aspect, it is possible to realize an ink jet recording apparatus having improved head durability and reliability.

According to an eighth aspect of the present invention, a lower electrode provided on one side of a substrate defining a cavity via an insulating layer, a piezoelectric layer provided on the lower electrode, and the piezoelectric layer Forming a piezoelectric element by sequentially laminating and patterning a lower electrode, a piezoelectric layer, and an upper electrode on the substrate and forming the piezoelectric element on the substrate, in a method of manufacturing an actuator device including a piezoelectric element including an upper electrode provided on a surface of the substrate. Forming a protective film on the surface of the piezoelectric element, forming the cavity in the substrate by etching with an alkaline solution, removing the protective film and cleaning the surface of the piezoelectric element with a predetermined cleaning liquid. And a method of manufacturing the actuator device.

In the eighth aspect, by cleaning the surface of the piezoelectric element, the concentration of the predetermined metal element existing on the surface of the piezoelectric layer is reduced, and dielectric breakdown of the piezoelectric layer is prevented.

A ninth aspect of the present invention is the ninth aspect, wherein:
In the step of cleaning the surface of the piezoelectric element,
The area of the outer peripheral surface of the element where the piezoelectric layer is exposed is reduced.
Alkali metal or alkaline earth metal both present in the surface layer
Each concentration of 1 × 10 ¹¹atoms / cm^TwoLess than
Method for manufacturing an actuator device
It is in.

According to the ninth aspect, the piezoelectric layer
The concentration of a specific metal element is 1 × 10 ¹¹atoms / cm
^TwoBy setting the following, dielectric breakdown of the piezoelectric layer can be more reliably
It is really prevented.

A tenth aspect of the present invention is the actuator device according to the ninth aspect, wherein the alkali metal or alkaline earth metal is selected from the group consisting of sodium, potassium, magnesium and calcium. In the manufacturing method.

In the tenth aspect, the dielectric breakdown of the piezoelectric layer is more reliably prevented by removing the specific metal element contained in the piezoelectric layer.

An eleventh aspect of the present invention is the method for manufacturing an actuator device according to the ninth or tenth aspect, wherein the predetermined cleaning liquid is an acidic solution or pure water.

In the eleventh aspect, by using the predetermined cleaning liquid, the alkali metal or alkaline earth metal element contained in the piezoelectric layer can be reliably removed.

A twelfth aspect of the present invention is the method for manufacturing an actuator device according to the eleventh aspect, wherein the acidic solution is hydrochloric acid or nitric acid.

In the twelfth aspect, by using a predetermined acidic solution, the alkali metal or alkaline earth metal element contained in the piezoelectric layer can be more reliably removed.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments.

(Embodiment 1) FIG. 1 is an exploded perspective view showing an ink jet recording head according to Embodiment 1 of the present invention. FIG. 2 is a plan view and a cross section of one of the pressure generating chambers in the longitudinal direction. It is a figure showing a structure.

As shown in the figure, the flow path forming substrate 10 is made of a silicon single crystal substrate having a plane orientation (110) in this embodiment. As the flow path forming substrate 10, usually 150 to 3
A thickness of about 00 μm is used.
Those having a thickness of about 0 to 280 μm, more preferably about 220 μm are suitable. This is because the arrangement density can be increased while maintaining the rigidity of the partition wall between the adjacent pressure generating chambers.

One surface of the flow path forming substrate 10 is an opening surface, and the other surface is formed with a 0.1 to 2 μm-thick elastic film 50 made of silicon dioxide previously formed by thermal oxidation.

On the other hand, a silicon single crystal substrate is anisotropically etched on the opening surface of the flow path forming substrate
A nozzle opening 11 and a pressure generating chamber 12 are formed.

Here, in the anisotropic etching, when a silicon single crystal substrate is immersed in an alkaline solution such as KOH, it is gradually eroded and the first (111) plane perpendicular to the (110) plane and the first (111) plane. A second (1) which forms an angle of about 70 degrees with the (111) plane and forms an angle of about 35 degrees with the (110) plane.
11) plane, and the etching rate of the (111) plane is about 1/1 compared to the etching rate of the (110) plane.
This is performed using the property of being 80.
By such anisotropic etching, two first (11
Precision processing can be performed based on depth processing of a parallelogram formed by the 1) plane and two oblique second (111) planes, and the pressure generating chambers 12 can be arranged at high density. it can.

In this embodiment, the long side of each pressure generating chamber 12 is formed by the first (111) plane, and the short side is formed by the second (111) plane. The pressure generating chamber 12 is provided on the flow path forming substrate 1.
It is formed by etching until it reaches the elastic film 50 almost through 0. The amount of the elastic film 50 that is attacked by the alkaline solution for etching the silicon single crystal substrate is extremely small.

On the other hand, each nozzle opening 11 communicating with one end of each pressure generating chamber 12 is formed narrower and shallower than the pressure generating chamber 12. That is, the nozzle opening 11 is formed by partially etching (half-etching) the silicon single crystal substrate in the thickness direction. In addition,
Half etching is performed by adjusting the etching time.

Here, the size of the pressure generating chamber 12 for applying the ink droplet ejection pressure to the ink and the size of the nozzle opening 11 for ejecting the ink droplet depend on the amount of the ejected ink droplet, the ejection speed, and the ejection frequency. Optimized. For example,
When recording 360 ink droplets per inch, the nozzle openings 11 need to be formed with a groove width of several tens of μm with high accuracy.

Further, each pressure generating chamber 12 and a common ink chamber 31 described later are connected to each pressure generating chamber 1 of the sealing plate 20 described later.
The ink is supplied from a common ink chamber 31 through the ink supply communication port 21 formed at a position corresponding to one end of the pressure generation chamber 12. Distributed to

The sealing plate 20 is provided with an ink supply communication port 21 corresponding to each of the pressure generating chambers 12 described above, and has a thickness of, for example, 0.1 to 1 mm and a linear expansion coefficient of 300 ° C. or less. , For example, 2.5-4.5 [× 10 ⁻⁶ / ° C.]. In addition, the ink supply communication port 21
Each of the pressure generating chambers 1 is, as shown in FIGS.
It may be one slit hole 21A crossing the vicinity of the second ink supply side end or a plurality of slit holes 21B. The sealing plate 20 is provided on one side with the flow path forming substrate 10.
, And also serves as a reinforcing plate for protecting the silicon single crystal substrate from impacts and external forces. Also, sealing plate 2
0 forms one wall surface of the common ink chamber 31 on the other surface.

The common ink chamber forming substrate 30 forms the peripheral wall of the common ink chamber 31, and is formed by punching a stainless steel plate having an appropriate thickness according to the number of nozzles and the ink droplet ejection frequency. . In the present embodiment, the thickness of the common ink chamber forming substrate 30 is 0.2 mm.

The ink chamber side plate 40 is made of a stainless steel substrate, and one surface of the ink chamber side plate 40 constitutes one wall surface of the common ink chamber 31. In the ink chamber side plate 40, a thin wall 41 is formed by forming a concave portion 40a by half etching on a part of the other surface, and an ink introduction port 42 for receiving ink supply from the outside is punched and formed. ing. The thin wall 41 is for absorbing pressure generated at the time of ink droplet ejection toward the side opposite to the nozzle opening 11, and is unnecessary for the other pressure generating chambers 12 via the common ink chamber 31. Prevents positive or negative pressure from being applied.
In the present embodiment, the ink chamber side plate 40 is made 0.2 mm in consideration of rigidity required at the time of connection between the ink introduction port 42 and an external ink supply means, and a part of the thickness is 0.02 mm.
The thickness of the ink chamber side plate 40 may be 0.02 mm from the beginning in order to omit the formation of the thin wall 41 by half etching.

On the other hand, the thickness of the elastic film 50 on the side opposite to the opening surface of the flow path forming substrate 10 is, for example, about 0.2 to 0.2.
The lower electrode film 60 having a thickness of about 1 μm
The piezoelectric layer 70 and the upper electrode film 80 having a thickness of, for example, about 0.1 μm are laminated and formed by a process described later, thereby forming the piezoelectric element 300. Here, the piezoelectric element 300
Denotes a portion including the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80. Generally, one of the electrodes of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 7 are used as a common electrode.
0 is patterned for each pressure generating chamber 12.
Here, a portion which is constituted by one of the patterned electrodes and the piezoelectric layer 70 and in which a piezoelectric strain is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion 320. In the present embodiment, the lower electrode film 60 is used as a common electrode of the piezoelectric element 300, and the upper electrode film 80 is used as an individual electrode of the piezoelectric element 300. However, there is no problem even if the upper electrode film 80 is reversed for convenience of a drive circuit and wiring. In any case, the piezoelectric active portion is formed for each pressure generating chamber. Also,
Here, a combination of the piezoelectric element 300 and an elastic film whose displacement is generated by driving the piezoelectric element 300 is referred to as a piezoelectric actuator. In the example described above, the elastic film 50 and the lower electrode film 60 function as a diaphragm, but the lower electrode film may also serve as the elastic film.

FIG. 4 is a plan view and a cross-sectional view showing a main part of the ink jet recording head of this embodiment.

As shown in FIG. 4, the lower electrode film 60 constituting the piezoelectric element 300 has a plurality of pressure generating chambers 12 arranged in parallel.
And is patterned in the vicinity of one longitudinal end of the pressure generating chamber 12. Also,
Outside the end of the lower electrode film 60, a lower electrode film 61 for wiring that is discontinuous from the lower electrode film 60 is provided from a region facing the pressure generating chamber 12 to the peripheral wall.

On the other hand, the piezoelectric layer 70 and the upper electrode film 80
Basically, a piezoelectric active portion 320 is provided in a region facing the pressure generating chamber 12. Further, one end in the longitudinal direction of the upper electrode film 80 and the piezoelectric layer 70 extends to the lower electrode film 61 for wiring, and the upper electrode film 80 and the lower electrode film 61 for wiring are connected via the lead electrode 90. Have been. Although not shown, one end of the lower electrode film 61 for the wiring is connected to an external wiring to constitute a part of the wiring of the piezoelectric active portion 320.

Here, a process of forming the piezoelectric element 300 and the like on the flow path forming substrate 10 made of a silicon single crystal substrate will be described with reference to FIGS. FIG.
6 is a longitudinal sectional view of the pressure generating chamber 12, and FIGS. 6 and 7 are sectional views of the pressure generating chamber 12 in the width direction.

First, as shown in FIG. 5 (a), a wafer of a silicon single crystal
Thermal oxidation is performed in a diffusion furnace at 0 ° C. to form an elastic film 50 made of silicon dioxide.

Next, as shown in FIG. 5B, a lower electrode film 60 is formed by sputtering. As a material of the lower electrode film 60, platinum or the like is preferable. This is because a piezoelectric layer 70 described later formed by a sputtering method or a sol-gel method is formed.
Is from 600 to 600 ° C. in an air atmosphere or an oxygen atmosphere after film formation.
This is because it is necessary to perform crystallization by firing at a temperature of about 1000 ° C. That is, the material of the lower electrode film 60 must be able to maintain conductivity under such a high temperature and oxidizing atmosphere. In particular, when the piezoelectric layer 70 is made of lead zirconate titanate (PZT), It is desirable that the change in conductivity due to the diffusion of lead oxide is small, and for these reasons, platinum is preferred.

Next, as shown in FIG. 5C, the lower electrode film 60 is patterned into a predetermined shape. That is, the lower electrode film 60 is patterned in a region opposed to the vicinity of one end in the longitudinal direction of the pressure generation chamber 12, and for each pressure generation chamber 12,
The lower electrode film 61 for wiring, which is provided from the vicinity of one end in the longitudinal direction to a region facing the peripheral wall, and is a part of a wiring connecting the upper electrode film 80 of the piezoelectric active portion 320 and an external wiring.
To form

Next, as shown in FIG. 5D, a piezoelectric layer 70 is formed. In this embodiment, a so-called sol in which a metal organic substance is dissolved and dispersed in a catalyst is applied, dried and gelled,
The piezoelectric layer 70 made of a metal oxide is obtained by firing at a higher temperature, that is, by using a so-called sol-gel method. As a material of the piezoelectric layer 70, a lead zirconate titanate (PZT) -based material is suitable when used in an ink jet recording head. Note that this piezoelectric layer 70
The film forming method is not particularly limited, and may be formed by, for example, a sputtering method.

Further, after forming a precursor film of lead zirconate titanate by a sol-gel method, a sputtering method or the like,
A method of growing crystals at a low temperature by a high-pressure treatment method in an alkaline aqueous solution may be used.

Next, as shown in FIG. 5E, an upper electrode film 80 is formed. The upper electrode film 80 only needs to be a material having high conductivity, and can use many metals such as aluminum, gold, nickel, and platinum, and a conductive oxide. In the present embodiment, platinum is formed by sputtering.

Next, as shown in FIG. 6A, the piezoelectric layer 70 and the upper electrode film 80 are collectively etched to pattern the piezoelectric active portion 320 in a region facing each pressure generating chamber 12. Do.

Next, as shown in FIG. 6B, for example, a conductor such as Cr-Au is formed on the entire surface and then patterned to form a wiring with the upper electrode film 80 of each piezoelectric active part 320. Lead electrode 9 connecting to lower electrode 61
0 is formed.

Next, as shown in FIG. 6C, a protective film 100 made of, for example, parylene is formed on the surface of the piezoelectric active portion 320. The protective film 100 is used for the piezoelectric element 30 during etching with an alkaline solution in the following steps.
0, in particular, to prevent the piezoelectric layer 70 from being destroyed.

Next, as shown in FIG. 7A, the silicon single crystal substrate is subjected to anisotropic etching with the above-described alkaline solution such as KOH to form the pressure generating chambers 12 and the like. As shown in FIG. 7, the protective film 100 is removed by, for example, dry etching.

Thereafter, in this embodiment, the piezoelectric element 300
Is cleaned by using a predetermined cleaning liquid, so that the ionization tendency existing on at least the surface layer of the surface of the piezoelectric layer 70 constituting the piezoelectric element 300, that is, the exposed portion of the piezoelectric layer 70 on the outer peripheral surface of the piezoelectric element 300 is obtained. , Specifically, an alkali metal or alkaline earth metal element is removed. At this time, the concentration of each alkali metal or alkaline earth metal element present in the piezoelectric layer was set to 1 × 10 ¹¹ a
toms / cm ² or less, preferably 1 × 10 ¹⁰ atoms
s / cm ² or less.

Here, examples of the alkali metal and alkaline earth metal elements include sodium, potassium, magnesium, calcium, lithium, rubidium and cesium.

As a cleaning solution used for such cleaning, for example, hydrochloric acid (HCl) or nitric acid (HN)
It is preferable to use an acidic solution such as O ₃ ) or pure water.

In the present embodiment, the piezoelectric element 300 is washed with a hydrochloric acid solution to remove at least the sodium, potassium, magnesium, and calcium metal elements present in the piezoelectric layer 70, and the concentration of each metal element is reduced to 1 × 1.
0 ¹¹ atoms / cm ² or less.

As described above, the dielectric breakdown of the piezoelectric layer 70 can be prevented by removing the alkali metal or alkaline earth metal element present in the piezoelectric layer 70 to a predetermined concentration or less.

Here, the inventor has found that the above-described alkali metal or alkaline earth metal element or the like is segregated in a place where the piezoelectric layer 70 of the piezoelectric element 300 causes dielectric breakdown. That is, the inventors have found that the alkali metal or alkaline earth metal element segregated in the piezoelectric layer is one of the causes of dielectric breakdown. From this, as described above, the alkali metal or alkaline earth metal element contained in the piezoelectric layer 70 is removed, and the concentration of each metal element is reduced to a predetermined concentration, specifically, 1 × 10 ¹¹ atoms / cm ² or less. Preferably, the dielectric breakdown of the piezoelectric layer 70 is prevented by setting it to 1 × 10 ¹⁰ atoms / cm ² or less.

It is considered that one of the main causes of segregation of the metal element in the piezoelectric layer 70 is due to the patterning of the pressure generating chamber 12 by an alkaline solution such as KOH. That is, when forming the pressure generating chamber 12 with an alkaline solution,
It is considered that the above-described metal element adheres to the protective film 100, and when the protective film 100 is removed, the metal element adhered to the protective film 100 is re-adhered to the piezoelectric layer 70.

For this reason, in this embodiment, the protective film 100
After removing, the piezoelectric element 300 was cleaned,
The cleaning is not limited to this, and the cleaning may be performed at any timing as long as the pressure generating chamber 12 is formed. For example, after forming the pressure generating chamber 12, the surface of the protective film 100 may be washed to remove each metal element as described above. In this case, when removing the protective film 100 as described above, the metal element does not re-attach to the piezoelectric layer 70 and the concentration of the alkali metal or alkaline earth metal element existing in the piezoelectric layer 70 is reduced. Can be set to 1 × 10 ¹¹ atoms / cm ² or less.

By the series of film formation and anisotropic etching described above, a large number of chips are simultaneously formed on one wafer, and after the process is completed, a flow path of one chip size as shown in FIG. It is divided for each forming substrate 10. Further, the divided flow path forming substrate 10 is sequentially adhered and integrated with the sealing plate 20, the common ink chamber forming substrate 30, and the ink chamber side plate 40 to form an ink jet recording head.

The ink-jet head thus configured takes in ink from an ink inlet 42 connected to an external ink supply means (not shown), fills the interior from the common ink chamber 31 to the nozzle opening 11 with ink, and
By applying a voltage between the lower electrode film 60 and the upper electrode film 80 according to a recording signal from an external drive circuit (not shown), the elastic film 50, the lower electrode film 60, and the piezoelectric layer 70 are flexibly deformed. The pressure in the pressure generating chamber 12 increases, and ink droplets are ejected from the nozzle opening 11.

(Other Embodiments) The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments.

For example, in the above-described embodiment, the pressure generating chamber 12 is formed with an alkaline solution such as KOH, and then the piezoelectric element 300 is washed to reduce the concentration of the metal element contained in the piezoelectric layer 70. However, the pressure generating chamber 12 may be formed by etching with an organic etching solution such as TMAH (tetramethylammonium hydroxide). In this case, when forming the pressure generating chamber 12, the alkali metal or alkaline earth metal element does not adhere to the protective film 100 or the like as described above. Therefore, these alkali metal or alkaline earth metal elements are
There is no segregation to zero.

In any case, if the concentration of the alkali metal or alkaline earth metal element present in the piezoelectric layer 70 of the piezoelectric element 300 is set to 1 × 10 ¹¹ atoms / cm ² or less,
The dielectric breakdown of the piezoelectric layer 70 caused by these metal elements can be prevented.

Further, for example, a sealing member for sealing the piezoelectric element 300 may be provided so as to block the piezoelectric element 300 from the external environment. Thus, since a change in the external environment such as humidity does not affect the piezoelectric layer 70, dielectric breakdown of the piezoelectric layer 70 can be more reliably prevented.

For example, in addition to the sealing plate 20 described above,
The common ink chamber forming substrate 30 may be made of glass ceramic, and further, the thin film 41 may be made of glass ceramic as a separate member, and the material, structure, and the like can be freely changed.

Further, in the above-described embodiment, the nozzle openings 11 are formed on the end surface of the flow path forming substrate 10, but may be formed so as to protrude in a direction perpendicular to the surface.

FIG. 8 is an exploded perspective view of the embodiment constructed as described above, and FIG. 9 is a sectional view of the flow path. In this embodiment, the nozzle opening 11 is formed in the nozzle substrate 120 opposite to the piezoelectric element, and the nozzle communication port 22 for communicating the nozzle opening 11 with the pressure generating chamber 12 is provided in the sealing plate 2.
0, it is arranged to penetrate the common ink chamber forming substrate 30, the thin plate 41A, and the ink chamber side plate 40A.

In this embodiment, the thin plate 41
A is basically the same as the above-described embodiment except that the ink chamber side plate 40A and the ink chamber side plate 40A are separate members, and the opening is formed in the ink chamber side plate 40A. Is omitted.

Further, needless to say, the present invention can be similarly applied to an ink jet recording head of a type in which a common ink chamber is formed in a flow path forming substrate.

As described above, the present invention can be applied to ink-jet recording heads having various structures, as long as the gist of the present invention is not contradicted.

The ink jet recording head of each of these embodiments constitutes a part of a recording head unit having an ink flow path communicating with an ink cartridge and the like, and is mounted on an ink jet recording apparatus. FIG.
FIG. 1 is a schematic view showing an example of the ink jet recording apparatus.

As shown in FIG. 10, recording head units 1A and 1B having an ink jet recording head are
Cartridges 2A and 2B constituting ink supply means are detachably provided. A carriage 3 on which the recording head units 1A and 1B are mounted is provided on a carriage shaft 5 attached to the apparatus main body 4 so as to be movable in the axial direction. I have. The recording head units 1A and 1B are, for example,
Each of them ejects a black ink composition and a color ink composition.

The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and a timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted moves along the carriage shaft 5. Moved. On the other hand, a platen 8 is provided on the apparatus main body 4 along the carriage shaft 5, and a recording sheet S, which is a recording medium such as paper fed by a paper feed roller (not shown), is wound around the platen 8. It is designed to be transported.

[0085]

As described above, in this embodiment, the concentration of the alkali metal or alkaline earth metal element present in the piezoelectric layer constituting the piezoelectric element is set to 1 × 10 ¹¹ atoms / cm ^2.
Because of the following, dielectric breakdown of the piezoelectric layer can be prevented, and durability and reliability of the head can be improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an ink jet recording head according to an embodiment of the present invention.

FIG. 2 is a plan view and a cross-sectional view of the inkjet recording head according to the first embodiment of the present invention, showing the same.

FIG. 3 is a perspective view showing a modification of the sealing plate.

FIG. 4 is a plan view and a cross-sectional view of a main part of the inkjet recording head according to the first embodiment of the invention.

FIG. 5 is a cross-sectional view illustrating a thin-film manufacturing process according to the first embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating a thin-film manufacturing process according to the first embodiment of the present invention.

FIG. 7 is a cross-sectional view illustrating a thin-film manufacturing process according to the first embodiment of the present invention.

FIG. 8 is an exploded perspective view of an ink jet recording head according to another embodiment of the present invention.

FIG. 9 is a cross-sectional view illustrating an ink jet recording head according to another embodiment of the present invention.

FIG. 10 is a schematic diagram of an ink jet recording apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Flow path forming substrate 12 Pressure generating chamber 50 Elastic film 60 Lower electrode film 70 Piezoelectric layer 80 Upper electrode film 300 Piezoelectric element 320 Piezoelectric active part

Claims (12)

[Claims] 1. A lower electrode provided on one surface side of a substrate defining a cavity via an insulating layer, a piezoelectric layer provided on the lower electrode, and an upper surface provided on a surface of the piezoelectric layer. In an actuator device including a piezoelectric element composed of an electrode, the concentration of each of the alkali metal or alkaline earth metal element present in at least the surface layer of the outer peripheral surface of the piezoelectric element where the piezoelectric layer is exposed is 1 × 10 ¹¹ atom
s / cm ² or less. 2. The actuator device according to claim 1, wherein the alkali metal or alkaline earth metal element is selected from the group consisting of sodium, potassium, magnesium and calcium. 3. The actuator device according to claim 1, wherein the cavity is formed by etching the substrate with an alkaline solution. 4. The actuator device according to claim 1, wherein the cavity is removed by an organic etching solution. 5. An ink jet printer, wherein a nozzle forming member having a nozzle opening communicating with the cavity is joined to the other surface of the substrate constituting the actuator device according to claim 1. Type recording head. 6. The method according to claim 5, wherein the cavity is formed in the silicon single crystal substrate by anisotropic etching.
An ink jet recording head, wherein each layer of the piezoelectric element is formed by film formation and lithography. 7. An ink jet recording apparatus comprising the ink jet recording head according to claim 5. 8. A lower electrode provided on one surface side of a substrate defining a cavity with an insulating layer interposed therebetween, a piezoelectric layer provided on the lower electrode, and an upper surface provided on a surface of the piezoelectric layer. A method of manufacturing an actuator device including a piezoelectric element including an electrode, a step of sequentially laminating and patterning a lower electrode, a piezoelectric layer, and an upper electrode on the substrate to form the piezoelectric element; Forming a cavity on the substrate by etching with an alkaline solution, and removing the protective film and cleaning the surface of the piezoelectric element with a predetermined cleaning liquid. Manufacturing method of an actuator device. 9. The method according to claim 8, wherein in the step of cleaning the surface of the piezoelectric element, an alkali metal or an alkaline earth metal present on at least a surface layer of the outer peripheral surface of the piezoelectric element where the piezoelectric layer is exposed. Each concentration of 1 ×
A method for manufacturing an actuator device, wherein the pressure is set to 10 ¹¹ atoms / cm ² or less. 10. The method according to claim 9, wherein said alkali metal or alkaline earth metal is selected from the group consisting of sodium, potassium, magnesium and calcium. 11. The method according to claim 9, wherein the predetermined cleaning liquid is an acidic solution or pure water. 12. The method according to claim 11, wherein the acidic solution is hydrochloric acid or nitric acid.