JP2007036141A - Piezoelectric element, piezoelectric actuator, ink jet recording head and ink jet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric element employing a piezoelectric film having proper piezoelectric characteristics, and to provide a piezoelectric actuator, an ink jet recording head and an ink jet printer. <P>SOLUTION: This piezoelectric element includes a piezoelectric film made of a perovskite oxide. In the perovskite oxide, where ions preferentially positioned in an A site, are referred to as "A-site" ions and ions positioned in a B site are referred to as "B-site" ions, the A-site ions are mutually substituted by the B-site ions. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a piezoelectric element, a piezoelectric actuator, an ink jet recording head, and an ink jet printer.

Inkjet printers are known as printers that enable high image quality and high-speed printing. The ink jet printer includes an ink jet recording head having a cavity whose internal volume changes, and performs printing by ejecting ink droplets from the nozzle while scanning the head. As a head actuator in such an ink jet recording head for an ink jet printer, a piezoelectric element using a piezoelectric film represented by PZT (Pb (Zr, Ti) O ₃ ) has been conventionally used (for example, Patent Document 1).
JP 2001-223404 A

  An object of the present invention is to provide a piezoelectric film having good piezoelectric characteristics. Another object of the present invention is to provide a piezoelectric element, a piezoelectric actuator, an ink jet recording head, and an ink jet printer using the piezoelectric film.

The piezoelectric element according to the present invention is
Including a piezoelectric film made of a perovskite oxide,
In the perovskite oxide, when an ion preferentially located at the A site is an A site ion and an ion preferentially located at the B site is a B site ion, the A site ion is the B site ion. Are mutually replaced.

In the piezoelectric element according to the present invention,
The valence of the A site ion may be equal to the valence of the B site ion.

In the piezoelectric element according to the present invention,
The ionic radius ratio of A site ions and B site ions can be 2 to 2.5.

In the piezoelectric element according to the present invention,
The A site ion can be a lead ion (Pb ²⁺ ).

In the piezoelectric element according to the present invention,
The perovskite oxide may be Pb (Mg, Nb) O ₃ —xPbTiO ₃ .

In the piezoelectric element according to the present invention,
The A site ion is a lead ion (Pb ²⁺ ),
The B site ion may be a magnesium ion (Mg ²⁺ ).

  The piezoelectric actuator according to the present invention can have the above-described piezoelectric element.

  The ink jet recording head according to the present invention can have the above-described piezoelectric element.

  The ink jet printer according to the present invention can have the ink jet recording head described above.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

1. Structure of Piezoelectric Film The piezoelectric film according to the present embodiment is made of a perovskite oxide. The perovskite type has a crystal structure as shown in FIGS. 1 (a) and 1 (b), and the position indicated by A in FIGS. 1 (a) and 1 (b) is shown at A site and B. The position is called B site, and the position indicated by O is called O site. In the present embodiment, ions preferentially located at the A site are referred to as A site ions, and ions preferentially located at the B site are referred to as B site ions. For example, in Pb (Mg, Nb) O ₃ −xPbTiO ₃ (hereinafter referred to as PMN-PT), the A site ion is Pb ²⁺ and the B site ion is Mg ²⁺ and Nb ⁵⁺ . Note that O ²⁻ is located at the O site. The perovskite oxide that constitutes the piezoelectric film includes a simple perovskite oxide and a composite perovskite oxide. The piezoelectric film can be made of a relaxor material.

In the piezoelectric film according to the present embodiment, A site ions and B site ions are mutually substituted. For example, when PMN-PT is used as the piezoelectric film, the crystal system is square when the B-site ion composition is adjusted to a morphotropic phase boundary (hereinafter referred to as MPB) (x≈0.35). Although it is a crystal or rhombohedral crystal, when Pb ²⁺ and Mg ²⁺ are mutually substituted, the crystal system becomes monoclinic or orthorhombic with less symmetry.

  Thus, by mutual substitution of the A site ion and the B site ion, the crystal symmetry of the perovskite oxide can be lowered, and the polarization inversion can be facilitated. Thereby, the piezoelectric characteristics of the piezoelectric film can be improved.

Moreover, it is preferable that the valence of the B site ion to be mutually substituted is equal to the valence of the A site ion. For example, when PMN-PT is used as the piezoelectric film, Mg ²⁺ is preferable to Nb ⁵⁺ as the B site ion for mutual substitution.

Moreover, it is preferable that the ionic radius ratio of the A site ion and B site ion to be mutually substituted is 2.0 to 2.5. Specifically, the case where the ionic radius of the A site ion is 2.0 to 2.5 times the ionic radius of the B site ion will be described. For example, when the piezoelectric film is made of a crystal in which the A site ion is Pb ²⁺ , such as PZT (Pb (Zr, Ti) O ₃ ) or PMN-PT, the ionic radius of Pb ²⁺ (12 coordination) (Shannon's) Since the ion radius) is 1.49 Å, the ionic radius of the mutually substituted B site ions can be 0.60 to 0.75 Å. Therefore, ^{Pb 2+} is, ^{Mg 2+} (6 coordination) (ionic radius 0.72 Å), ^{Zn 2+} (ionic radius 0.745Å), ^{Nb 2+} (ionic radius 0.71 Å), ^{Co 2+} (ionic radius 0.65A) , Cr ²⁺ (ion radius 0.73Å), Mn ²⁺ (ion radius 0.67Å), Fe ²⁺ (ion radius 0.61Å), Cu ²⁺ (ion radius 0.73Å), and the like.

  As a result, the crystal structure can be greatly changed, and the crystal symmetry of the perovskite oxide can be significantly reduced. Thereby, the piezoelectric characteristics of the piezoelectric film can be further improved.

  Note that the mutual substitution between the A site ion and the B site ion can be 2 at% or more of the entire crystal. As a result, the crystal symmetry of the perovskite oxide can be significantly reduced. Thereby, the piezoelectric characteristics of the piezoelectric film can be further improved.

  The piezoelectric film has a layered multi-domain structure and a mosaic structure of, for example, 10 nm or more. A multi-domain structure refers to a single crystal in which domains having different orientations are mixed. Here, the orientation may be different for all of the a-axis, b-axis, and c-axis, or any one or two axes may be different. Thereby, the stress of a piezoelectric film can be relieved and crack resistance can be improved. A mosaic structure means that domains adjacent to each other have slightly different orientations (1 degree or less). When the piezoelectric film has a mosaic structure, the stress of the piezoelectric film can be relaxed and the crack resistance can be improved.

2. Experimental Example 2.1. Sample preparation
A (001) -oriented PMN-xPT (x = 32, 37 at%) single crystal was produced by the Bridgman method. Ag was formed as an evaluation electrode and subjected to polarization treatment with an electric field of 1 kV / mm.

The Bridgman method is a method of growing a crystal while gradually lowering a crucible enclosing a single crystal raw material, and mononucleating using a temperature gradient generated at a heater end portion. Pt crucible was filled with PbO, MgO, Nb ₂ O ₅ , TiO ₂ (each purity 99.99% or more) powder of PMN-PT at a ratio of each condition, and the crucible was placed in the furnace at 1380 ° C. or higher. Dissolve. After holding for about 10 hours, it was lowered at a speed of 0.1 to 1 mm / h to obtain a (001) -oriented PMN-xPT single crystal.

  A single crystal with x = 32 at% is designated as PMN-32PT, and a single crystal with x = 37 at% is designated as PMN-37PT.

2.2. Evaluation Method and Evaluation Results The following evaluations were performed on the obtained samples.

2.2.1. Quantitative analysis Quantitative analysis was performed with an electron probe microanalyzer (EPMA) and an inductively coupled plasma emission analyzer (ICP-AES) using PMN-32PT and PMN-37PT single crystals. As a pretreatment for ICP-AES, a sample was hydrolyzed with nitric acid, hydrofluoric acid and perchloric acid, heated and dissolved with dilute nitric acid and dilute hydrofluoric acid, and filtered. The filtrate was made up to volume with dilute nitric acid. The insoluble matter was decomposed by heating with nitric acid and sulfuric acid, and heated and dissolved with dilute nitric acid and dilute hydrofluoric acid to obtain a constant volume. The chemical formulas of PMN-32PT and PMN-37PT were determined using the results of quantitative analysis.

The chemical formula based on the B site of PMN-32PT is
(1-0.32) [Pb _0.99 (Mg _0.33 Nb _0.67 ) O _3.16 ] -0.32 Pb _0.99 TiO _3.16
Met.

The chemical formula of PMN-37PT is
(1-0.37) _{[Pb 1.00 (Mg 0.33 Nb 0.67)} O 3.02 ] _-0.37Pb 1.00 _{TiO 3.02}
Met.

2.2.2. Angle-resolved electron channeling X-ray spectroscopy (ALCHEMI-HARECXS)
Angle-resolved electron channeling X-ray spectroscopy is a technique in which a sample is irradiated with an electron beam from a plurality of incident directions and a crystal structure is analyzed using characteristic X-rays generated from the sample. In this measurement method, when a sample is irradiated with an electron beam and strong diffraction occurs in the sample, the incident electrons repeatedly scatter between transmitted waves and diffracted waves inside the sample, and the amplitude maximum is applied to a specific part of the crystal. Branches into several Bloch wave components. The excitation amplitude of each Bloch wave component depends on the incident direction of the electron beam. When a certain Bloch wave component is excited strongly, the incident electrons cause channeling that concentrates on a specific part of the crystal. The characteristic X-ray signal from the elements present in is enhanced. By this measurement, information on the types and amounts of elements located at specific crystal sites can be obtained.

  PMN-32PT was analyzed by angle-resolved electron channeling X-ray spectroscopy. The experiment was performed on 111 and 130 system reflection rows.

  The 111 system reflection column is a surface on which the A-O site and the B site can be separated, and the 130 system reflection column is a surface on which the A-B site and the O site can be separately observed.

  In the 111 system, the characteristic X-ray intensity change of each constituent element when continuously inclined from −3 g to 2 g black condition, and in the 130 system from −2 g to 2 g black condition was continuously observed, and FIG. ) And the profile shown in FIG.

  FIG. 2 (a) shows the ALCHEMI-HARECXS experimental profile of PMN-32PT with 111-line reflection train. FIG. 2B shows the theoretical value of the ALCHEMI-HARECXS profile of the 111 system reflection train.

In the experiment, the sample is tilted so as to be the [112] zone axis from [110], which is the sample preparation direction, and the sample is tilted to the [−110] direction therefrom, and only the g = 111 system reflection row is excited. It was. And the characteristic X-ray intensity change of each constituent element when making it incline continuously from -3g to 2g black conditions was observed continuously, and the profile was obtained. For comparison, Pb ²⁺ , Mg ²⁺ , Nb ⁵⁺ , Ti ⁴⁺ , and O ²⁻ occupy A, B, B, B, and O sites, respectively, based on the dynamic diffraction theory considering inner-shell electron excitation. FIG. 2 (b) shows a HARECXS theoretical profile assuming an ideal ion arrangement (no spontaneous displacement, no defect, sample thickness 150 nm). The HARECXS theoretical profile indicates the X-ray generation cross section (probability of generation) per atom of each normalized site. In order to simplify the calculation, the crystal structure is a cubic crystal (lattice constant: 4.018Å).

In FIG. 2 (a), the characteristic X-ray intensity varies greatly depending on the diffraction conditions, and in the range of −1 <k / g111 <1 with the symmetrical excitation condition in between, the values from Pb ²⁺ and O ²⁻ The signal was strong, and on the contrary, the signals of Nb ⁵⁺ and Ti ⁴⁺ were weakened, and it was confirmed that this intensity relationship was reversed on the higher-order reflection side. These trends are consistent with the theoretical intensity profile shown in FIG. 2 (b), the A-O site located is ^{Pb 2+} and O ^{2 over, the Nb 5+} and ^{Ti 4+} are located in the B-site Is qualitatively understood. Further, it was confirmed that Mg ²⁺ was deficient or substituted because the diffraction condition was weakly dependent and the behavior was clearly different from the theoretical intensity profile.

Next, FIG. 3A shows an ALCHEMI-HARECXS profile of the 130 system reflection row. In the experiment, the sample was tilted from the [−310] zone axis, which is the sample preparation direction, to the [001] direction, and only the g = 130 system reflection train was excited. And the characteristic X-ray intensity change of each constituent element when making it incline continuously from -2g to 2g black conditions was observed continuously, and the profile was obtained. For comparison, an ideal ion arrangement in which Pb ²⁺ , Mg ²⁺ , Nb ⁵⁺ , Ti ⁴⁺ , and O ²⁻ occupy A, B, B, B, and O sites (no spontaneous displacement, no defect, sample thickness of 100 nm, respectively) FIG. 3 (b) shows a HARECXS theoretical profile that assumes).

In FIG. 3A, the characteristic X-ray intensity greatly changes depending on the diffraction conditions, and Pb ²⁺ , Mg ²⁺ , Nb ^{5+ in} the range of −1 <k / g130 <1 with the symmetric excitation condition interposed. , Ti ⁴⁺ signal is strong, and this intensity relationship is reversed on the higher-order reflection side. On the other hand, it can be seen that the O ²⁻ signal shows almost no dependence on the diffraction conditions. These tendencies agree with the theoretical intensity profile shown in FIG. 3 (b), where Pb ²⁺ , Mg ²⁺ , Nb ⁵⁺ , Ti ⁴⁺ are located at the AB site, and O ²⁻ is located at the O site. It is understood qualitatively.

FIG. 4B is a HARECXS theoretical profile when Mg ²⁺ and Pb ²⁺ are mutually substituted. FIG. 4 (a) shows the ALCHEMI-HARECXS experimental profile as in FIG. 2 (a). Specifically, FIG. 4B shows that about 45% (about 2 at%) of Mg ²⁺ (total amount of 4.32 at%) is transferred to the A site, and about 10% of the equivalent amount of Pb ²⁺ (total amount of 19.15 at%) ( (About 2 at%) is a HARECXS theoretical profile when B site is substituted. Since FIG. 4B substantially coincides with FIG. 4A, it was confirmed that the A site ion and the B site ion were mutually substituted in PMN-32PT.

  FIG. 3 (a) shows the ALCHEMI-HARECXS profile of the PMN-32PT of the 130 system reflection train. FIG.3 (b) shows the theoretical value of the ALCHEMI-HARECXS profile of 130 system | strain reflective row | line | column.

  Similarly, it was confirmed that the A-site ion and the B-site ion were mutually substituted in the PMN-32PT for the 130 system reflection row.

In addition, depending on the ion species located at each site of the perovskite structure, the method of taking a crystal system is different, and there is Tolerance factor (t) as a guide. Radius _r A of the A ion radius _r B of B ions, when the radius _{r O} in the O ions,
t = (r _A + r _O ) / √2 (r _B + r _O )
The following relational expression is obtained. In PMN-32PT, if the t value is calculated from the lattice occupancy at each site, t≈0.91, whereas in the state where there is no substitution of Pb ²⁺ and Mg ²⁺ , t≈0.97, and it is understood that distortion occurs due to substitution. Is done. Further, the decrease in crystal symmetry was linked to the magnitude of the tilt of the oxygen octahedron, and it was confirmed from the B site ion displacement and the Tolerance factor that the symmetry decreased due to substitution.

2.2.3. Domain structure analysis Domain structure analysis of PMN-32PT was performed by a high resolution energy filter TEM (Transmission Electron Microscopy) method.

  FIG. 5 shows [110] incident EF-TEM bright-field images of PMN-32PT and PMN-37PT single crystals polarized in the [001] direction with an electric field of 1 kV / mm, and (100), (110) , (111) Reflected excitation dark field image (where the white contrast portion is reflected and excited). Single crystals tend to align the direction of spontaneous polarization relatively uniformly compared to ceramics, but each composition has a domain wall that fluctuates along the [001] polarization orientation, and is 10 nm or more mirror-symmetrically. A width-like fine multi-domain structure could be confirmed.

  FIG. 6 shows limited field electron diffraction patterns of [100], [110], and [111] incidence obtained from the φ0.95 μm region of PMN-32PT and PMN-37PT. In all cases, only the basic lattice reflection appeared, and no superlattice reflection was observed. The multi-domain region is also composed of a single crystal diffraction pattern, but a slight split was observed in higher-order reflection. Therefore, the identification of the crystal system was attempted as follows using the split of higher-order reflection.

  FIG. 7 shows restricted field electron diffraction patterns of high-order reflection of [110] and [111] incidence obtained from the φ0.25 μm region of PMN-32PT and PMN-37PT. FIG. 8 shows the results of an electron diffraction simulation modeling the reflection split of PMN-32PT and PMN-37PT. At the [110] incidence of PMN-32PT, a split along the 001 system train was observed by 00-4 reflection of the 001 system train, and a split along the 001 system train was observed by -440 reflection of the 110 system train. In addition, splitting was observed with -12-1 reflection from [111] incidence in the same region. Furthermore, in another field of view, three splits along the 001 series were observed with [110] incident 004 reflection. This means that the three axial lengths of the unit cell are different from each other, and the crystal system is considered to belong to symmetry below orthorhombic. According to the structure model assuming a monoclinic system, the positional relationship of the split is a combination of two types of domains of [110] + [101] ([111] + [− 111]), that is, a mixture of orientations ( b, c axis mixed).

  In the [110] incidence of PMN-37PT, three splits were observed in the 00-6 series of 00-6 reflections, and three splits were also observed in the 110 series of -330 reflections. Of these, two splits have the same axial length, and the remainder has a shorter axial length. In addition, three splits were observed with -440 reflection from [111] incidence in the same region. Furthermore, when the field of view was moved while observing the electron diffraction pattern, it was confirmed that the diffraction pattern rotated slightly and had a mosaic structure. According to the structural model assuming a tetragonal system, the positional relationship between these splits is that [10-1] and [110] are slightly rotated in the clockwise and counterclockwise directions by the same angle (hereinafter referred to as [10-1] + [110] ± rotation, [111] + [-1-1-1] ± rotation), a combination of three types of domains, that is, mixed orientation (a = b, c-axis mixed) and mosaic structure (c-axis is The introduction of a slight rotation in the clockwise / counterclockwise direction was confirmed.

2.2.4. Hysteresis Characteristics FIG. 9 shows a butterfly curve showing the hysteresis characteristics of PMN-32PT. According to this, it was confirmed that there was a slight shift from the engineered domain because of some hysteresis. When the crystal system is monoclinic, the linear axis connecting the tetragonal polarization axis [001] and the orthorhombic polarization axis [101], or the tetragonal polarization axis [001] and the rhombohedral polarization axis [111]. ], The hysteresis increases as the deviation from the orthorhombic or rhombohedral crystal increases. The hysteresis characteristics shown in FIG. 9 confirmed that the monoclinic structure approximated to orthorhombic or rhombohedral.

3. Application example 3.1. Inkjet recording head Next, an inkjet recording head using a piezoelectric element will be described. FIG. 10 is a side sectional view showing a schematic configuration of an ink jet recording head using a piezoelectric element, and FIG. 11 is an exploded perspective view of the ink jet recording head. In addition, FIG. 11 is shown upside down from the state normally used.

  As shown in FIG. 10, the ink jet recording head (hereinafter also referred to as “head”) 50 includes a head main body 57 and a piezoelectric portion 54 provided on the head main body 57. 10 corresponds to the piezoelectric element according to the present embodiment. In the ink jet recording head according to the present embodiment, the piezoelectric element can function as a piezoelectric actuator. A piezoelectric actuator is an element having a function of moving a certain substance. The piezoelectric element includes, for example, a lower electrode 4, a piezoelectric film 5 formed above the lower electrode 4, and an upper electrode 6 formed above the piezoelectric film 5.

  As shown in FIG. 11, the head 50 includes a nozzle plate 51, an ink chamber substrate 52, an elastic film 55, and a piezoelectric portion (vibration source) 54 bonded to the elastic film 55, and these are housed in a base 56. Has been configured. The head 50 constitutes an on-demand piezo jet head.

  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.

  An ink chamber substrate 52 is fixed (fixed) to the nozzle plate 51. The ink chamber substrate 52 is formed by the substrate 2 described above. The ink chamber substrate 52 has a plurality of cavities (ink cavities) 521, a reservoir 523, and supply ports 524 formed by a nozzle plate 51, side walls (partition walls) 522, and an elastic film 55 described later. It is. The reservoir 523 temporarily stores ink supplied from the ink cartridge 631 (see FIG. 14). Ink is supplied from the reservoir 523 to each cavity 521 through the supply port 524.

  The cavities 521 are disposed corresponding to the respective nozzles 511 as shown in FIGS. The cavities 521 each have a variable volume due to vibration of an elastic film 55 described later. The cavity 521 is configured to eject ink by this volume change.

  An elastic film 55 is disposed on the side of the ink chamber substrate 52 opposite to the nozzle plate 51. Further, a plurality of piezoelectric portions 54 are provided on the side of the elastic film 55 opposite to the ink chamber substrate 52. As shown in FIG. 11, a communication hole 531 is formed at a predetermined position of the elastic film 55 so as to penetrate in the thickness direction of the elastic film 55. Ink is supplied from an ink cartridge 631 to be described later to the reservoir 523 through the communication hole 531.

  As described above, each piezoelectric portion 54 is configured such that the piezoelectric film 5 is interposed between the lower electrode 4 and the upper electrode 6. Each piezoelectric portion 54 is electrically connected to a piezoelectric element driving circuit described later, and is configured to operate (vibrate, deform) based on a signal from the piezoelectric element driving circuit. That is, each piezoelectric part 54 functions as a vibration source (head actuator). The elastic film 55 vibrates (deflection) due to vibration (deflection) of the piezoelectric portion 54 and functions to instantaneously increase the internal pressure of the cavity 521.

  The base 56 is made of, for example, various resin materials, various metal materials, or the like. As shown in FIG. 11, the ink chamber substrate 52 is fixed and supported on the base 56.

3.2. Operation of Inkjet Recording Head Next, the operation of the inkjet recording head 50 in the present embodiment will be described. In the head 50 according to the present embodiment, a voltage is not applied between the lower electrode 4 and the upper electrode 6 of the piezoelectric portion 54 in a state where a predetermined ejection signal is not input via the piezoelectric element driving circuit. In the state, the piezoelectric film 5 is not deformed as shown in FIG. For this reason, the elastic film 55 is not deformed and the volume of the cavity 521 is not changed. Accordingly, no ink droplet is ejected from the nozzle 511.

  On the other hand, in a state where a predetermined ejection signal is input via the piezoelectric element driving circuit, that is, in a state where a constant voltage (for example, about 30 V) is applied between the lower electrode 4 and the upper electrode 6 of the piezoelectric portion 54, As shown in FIG. 13, the piezoelectric film 5 is bent and deformed in the short axis direction. As a result, the elastic film 55 bends by, for example, about 500 nm, and the volume of the cavity 521 changes. At this time, the pressure in the cavity 521 increases instantaneously, and an ink droplet is ejected from the nozzle 511.

That is, when a voltage is applied, the crystal lattice of the piezoelectric film 5 is stretched in a direction perpendicular to the surface, but is simultaneously compressed in a direction parallel to the surface. In this state, a tensile stress is acting in the plane for the piezoelectric film 5. Therefore, the elastic film 55 is deflected and bent by this stress. The greater the displacement amount (absolute value) of the piezoelectric film 5 in the minor axis direction of the cavity 521, the greater the deflection amount of the elastic film 55, making it possible to eject ink droplets more efficiently. . In the present embodiment, as described above, the piezoelectric constant (d ₃₁ ) of the piezoelectric film 5 of the piezoelectric portion 54 (piezoelectric element) is high, so that a greater deformation is made with respect to the applied voltage. . Thereby, the amount of deflection of the elastic film 55 is increased, and ink droplets can be ejected more efficiently.

  Here, “efficient” means that the same amount of ink droplets can be ejected with a smaller voltage. That is, the driver circuit can be simplified and the power consumption can be reduced at the same time, so that the pitch of the nozzles 511 can be formed with higher density. Alternatively, since the length of the long axis of the cavity 521 can be shortened, the entire head can be reduced in size.

  When the ejection of one ink is completed, the piezoelectric element driving circuit stops applying the voltage between the lower electrode 4 and the upper electrode 6. Thereby, the piezoelectric part 54 returns to the original shape shown in FIG. 12, 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 cavity 521 from the nozzle 511, and an amount of ink corresponding to the ink ejection amount is supplied from the ink cartridge 631 to the cavity 521 through the reservoir 523.

  In this way, arbitrary (desired) characters and figures are printed by sequentially inputting ejection signals via the piezoelectric element driving circuit to the piezoelectric unit 54 at the position where ink droplets are to be ejected. be able to.

3.3. Method for Manufacturing Inkjet Recording Head Next, an example of a method for manufacturing the inkjet recording head 50 in the present embodiment will be described.

  First, a base material (substrate) to be the ink chamber substrate 52 is prepared. Next, an elastic film 55 is formed on the substrate. Next, the lower electrode 4, the piezoelectric film 5, and the upper electrode 6 are sequentially formed on the elastic film.

  Next, the upper electrode 6, the piezoelectric film 5, and the lower electrode 4 are patterned to correspond to the individual cavities 521 as shown in FIGS. 12 and 13, and as shown in FIG. The number of piezoelectric portions 54 corresponding to the number is formed.

  Next, the base material to be the ink chamber substrate 52 is processed (patterned) to form recesses to be the cavities 521 at positions corresponding to the piezoelectric portions 54, and recesses to be the reservoirs 523 and the supply ports 524 at predetermined positions. To do.

  The ink chamber substrate 52 is formed by removing the base material by etching until the elastic film 55 is exposed in the thickness direction. At this time, a portion left without being etched becomes the side wall 522.

  Next, the nozzle plate 51 on which the plurality of nozzles 511 are formed is aligned so that each nozzle 511 corresponds to a concave portion that becomes each cavity 521, and bonded in that state. Thereby, a plurality of cavities 521, a reservoir 523, and a plurality of supply ports 524 are formed. For the joining of the nozzle plate 51, for example, an adhesive method using an adhesive or a fusion method may be used. Next, the ink chamber substrate 52 is attached to the base 56.

  Through the above steps, the ink jet recording head 50 according to the present embodiment can be manufactured.

3.4. Action / Effect According to the ink jet recording head 50 according to the present embodiment, as described above, since the piezoelectric portion 54 has good piezoelectric characteristics, it is possible to efficiently eject ink. The density of the nozzles 511 can be increased. Therefore, high-density printing and high-speed printing are possible. Furthermore, the entire head can be reduced in size.

3.5. Inkjet Printer Next, an inkjet printer provided with the above-described inkjet recording head 50 will be described. FIG. 14 is a schematic configuration diagram showing an embodiment in which the inkjet printer 600 of the present invention is applied to a general printer that prints on paper or the like. In the following description, the upper side in FIG. 14 is referred to as “upper part” and the lower side is referred to as “lower part”.

  The ink jet printer 600 includes an apparatus main body 620, has a tray 621 for placing the recording paper P on the upper rear side, has a discharge port 622 for discharging the recording paper P on the lower front, and has an operation panel 670 on the upper surface. Have

  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.

  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 receives the rotation of the carriage motor 641 to reciprocate the head unit 630.

  The head unit 630 includes an ink jet recording head 50 provided with the above-described many nozzles 511, an ink cartridge 631 for supplying ink to the ink jet recording head 50, an ink jet recording head 50, and an ink cartridge 631 at a lower portion thereof. And a carriage 632 mounted thereon.

  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 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 ink jet recording head 50 and printing on the recording paper P is performed.

  The sheet feeding device 650 includes a sheet feeding motor 651 serving as a driving source thereof, and a sheet feeding roller 652 that rotates by the operation of the sheet feeding motor 651. The paper feed roller 652 includes a driven roller 652 a and a drive roller 652 b that are opposed to each other across the feeding path (recording paper P) of the recording paper P, and the driving roller 652 b is connected to the paper feeding motor 651. Has been.

  According to the ink jet printer 600 according to the present embodiment, as described above, since the ink jet recording head 50 having high performance and high nozzle density is provided, high density printing and high speed printing are possible. .

  The ink jet printer 600 of the present invention can also be used as an industrially used droplet discharge device. In that case, as the ink to be ejected (liquid material), various functional materials can be used by adjusting them to an appropriate viscosity with a solvent or a dispersion medium.

  As described above, the embodiments of the present invention have been described in detail. However, those skilled in the art can easily understand that many modifications can be made without departing from the novel matters and effects of the present invention. . Accordingly, all such modifications are intended to be included in the scope of the present invention.

The figure for demonstrating the crystal structure of a perovskite type oxide. FIG. 2 (a) shows the ALCHEMI-HARECXS experimental profile of PMN-32PT with 111-line reflection train. FIG. 2 (b) shows the HARECX theoretical profile of PMN-32PT with 111 system reflection rows. FIG. 3 (a) shows the ALCHEMI-HARECXS experimental profile of PMN-32PT with 130 system reflection rows. FIG. 3 (b) shows a HARECXS theoretical profile of PMN-32PT with 130 system reflection rows. FIG. 4 (a) shows the ALCHEMI-HARECXS experimental profile of PMN-32PT with 111 system reflection rows. FIG. 2 (b) shows a HARECXS theoretical profile of PMN-32PT of 111-line reflection train when A site ion and B site ion are mutually substituted. [110] incident EF-TEM bright field images of PMN-32PT and PMN-37PT single crystals polarized in the [001] direction with an electric field of 1 kV / mm, and (100), (110), (111) It is a figure which shows a reflection excitation dark field image. It is a figure which shows the limited field electron diffraction pattern of (100), (110), and (111) incidence obtained from the (phi) 0.95 micrometer area | region of PMN-32PT and PMN-37PT. It is a figure which shows the restricted field electron diffraction pattern of (110) and (111) incidence obtained from the (phi) 0.25 micrometer area | region of PMN-32PT and PMN-37PT. It is a figure which shows the electron diffraction simulation result which modeled the split of reflection of PMN-32PT and PMN-37PT. It is a figure which shows the hysteresis characteristic of PMN-32PT. 1 is a schematic configuration diagram of an ink jet recording head according to an embodiment. 1 is an exploded perspective view schematically illustrating a configuration of an ink jet recording head according to an embodiment. FIG. 4 is a diagram for explaining the operation of an ink jet recording head. FIG. 4 is a diagram for explaining the operation of an ink jet recording head. 1 is a schematic configuration diagram of an ink jet printer according to an embodiment.

Explanation of symbols

4 Lower electrode, 5 Piezoelectric film, 6 Upper electrode, 50 Inkjet recording head, 51 Nozzle plate, 52 Ink chamber substrate, 54 Piezoelectric section, 55 Elastic plate, 56 Base, 57 Head body, 511 Nozzle, 521 Cavity, 522 Side wall, 523 reservoir, 524 supply port, 531 communication hole, 600 inkjet printer, 620 device main body, 621 tray, 622 discharge port, 630 head unit, 631 ink cartridge, 632 carriage, 640 printing device, 641 carriage motor, 642 reciprocation Moving mechanism, 643 carriage guide shaft, 644 timing belt, 650 sheet feeding device, 651 sheet feeding motor, 652 sheet feeding roller, 660 control unit, 670 operation panel

Claims (9)

Including a piezoelectric film made of a perovskite oxide,
In the perovskite oxide, when the ion preferentially located at the A site is the A site ion and the ion preferentially located at the B site is the B site ion, the A site ion is the B site ion. Piezoelectric elements that are mutually replaced. In claim 1,
The piezoelectric element in which the valence of the A site ion is equal to the valence of the B site ion. In claim 1 or 2,
A piezoelectric element having an ion radius ratio of A site ions to B site ions of 2.0 to 2.5. In any of claims 1 to 3,
The A-site ion is a lead ion (Pb ²⁺ ), a piezoelectric element. In any of claims 1 to 4,
The piezoelectric element, wherein the perovskite oxide is Pb (Mg, Nb) O ₃ —xPbTiO ₃ . In claim 5,
The A site ion is a lead ion (Pb ²⁺ ),
The piezoelectric element, wherein the B site ions are magnesium ions (Mg ²⁺ ).   A piezoelectric actuator comprising the piezoelectric element according to claim 1.   An ink jet recording head comprising the piezoelectric element according to claim 1.   An ink jet printer comprising the ink jet recording head according to claim 9.