JP2004304027A - Piezoelectric actuator, ink jet recording head, method for adjusting piezoelectric characteristic and method for adjusting ink discharge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric actuator, an ink jet recording head, a method for adjusting the piezoelectric characteristics and a method for adjusting the ink discharge for quickly and accurately and easily grasping the piezoelectric characteristics of a piezoelectric displacement position without damaging the surface electrode. <P>SOLUTION: This piezoelectric actuator 7 is configured by laminating a common electrode 6 and a piezoelectric ceramic layer 2 on a diaphragm in this order, and laminating the surface electrodes 3 on the surface of the piezoelectric ceramic layer 2 to form a piezoelectric displacement part 8, and forming the electrodes 5 for inspection on the piezoelectric ceramic layer 2. Also, an ink jet recording head 10 is configured by mounting the piezoelectric actuator 7 on a channel member 11 on which a plurality of ink channels having ink discharge holes are arrayed by arranging the positions of the ink channels and the surface electrodes 3. In this invention, capacitance between the electrodes 5 for inspection and the common electrode 6 is measured, and a voltage to be applied to a gap between the surface electrodes 3 and the common electrode 6 is controlled based on this so that the piezoelectric characteristics and ink discharge can be adjusted. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a piezoelectric actuator used for positioning or pressing various devices by generating a minute displacement, an ink jet recording head having the same, a method for adjusting piezoelectric characteristics, and a method for adjusting an ink ejection amount. is there.
[0002]
[Prior art]
Conventionally, products using piezoelectric ceramics include, for example, piezoelectric actuators, filters, piezoelectric resonators (including oscillators), ultrasonic vibrators, ultrasonic motors, and piezoelectric sensors.
[0003]
Among these, the piezoelectric actuator has a very high response speed to an electric signal of the order of 10 ⁻⁶ seconds, and is therefore used as an actuator for positioning an XY stage of a semiconductor manufacturing apparatus or an actuator used for an ink jet recording head of a printer. Applied.
[0004]
In the ink jet recording head, for example, as shown in FIG. 3, a plurality of ink flow paths 33a are arranged in parallel, and a piezoelectric actuator 34 is provided on a flow path member 33 in which a partition wall 33b is formed as a wall separating each ink flow path 33a. It has a provided structure (see Patent Document 1).
[0005]
In the piezoelectric actuator 34, a piezoelectric ceramic layer 35 is stacked on a conductive common electrode 36 also serving as a diaphragm, and a plurality of surface electrodes 37 are arranged on the surface of the piezoelectric ceramic layer 35 to form a piezoelectric displacement portion 38. It is a plurality formed. The piezoelectric actuator 34 is stacked on the flow path member 33 such that the surface electrode 37 is located on the ink flow path 33a.
[0006]
The above-described ink jet recording head applies a voltage between the common electrode 36 and a predetermined surface electrode 37 to displace the piezoelectric ceramic layer 35 immediately below the surface electrode 37, thereby causing the ink in the ink flow path 33a to be displaced. To discharge ink droplets from the ink discharge holes 33 c opened in the bottom surface of the flow path member 33.
[0007]
However, in such an ink jet recording head, variations in piezoelectric characteristics may occur between the piezoelectric actuators, resulting in variations in the ink discharge amount. This variation in the ink ejection amount causes a variation in the dot size at the time of printing, resulting in a reduction in print quality such as blurred images.
[0008]
On the other hand, Patent Literature 2 and Patent Literature 3 propose that the effective electrode area is controlled by trimming the electrode, and the ink ejection amount is adjusted to reduce variations in the ink ejection amount. However, the piezoelectric actuators described in Patent Literature 2 and Patent Literature 3 have a problem that much time is required for trimming. In addition, when the integration degree of the piezoelectric actuator is increased, the size of the electrodes is also reduced, so that the pad area with which the trimming probe contacts cannot be secured, and there is a problem that fine adjustment of trimming becomes difficult.
[0009]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 11-34321
[Patent Document 2]
JP-A-61-118261 [Patent Document 3]
Japanese Patent Application Laid-Open No. 2002-307696
[Problems to be solved by the invention]
By the way, in order to adjust the dispersion of the piezoelectric characteristics occurring between the piezoelectric actuators to an appropriate value, before mounting the piezoelectric actuator on the flow path member, the capacitances of a plurality of piezoelectric displacement parts are directly measured and the piezoelectric characteristics of the piezoelectric actuator are measured. Is inspected, and if there is a variation in the piezoelectric characteristics between the piezoelectric actuators, the voltage applied between the surface electrode and the common electrode is controlled based on the inspection result to obtain a variation in the piezoelectric characteristics and the ink ejection amount. Can be reduced.
[0011]
However, when directly measuring the capacitance of the piezoelectric displacement unit, there is a risk that the surface electrode may be damaged by attaching a measurement probe to the surface electrode. Further, since a plurality of piezoelectric displacement parts are formed in the piezoelectric actuator mounted on the ink jet recording head, there is a problem that it takes much time to measure the capacitance of each piezoelectric displacement part. Further, in a piezoelectric actuator having a high degree of integration, there is a problem that it is difficult to accurately attach a measurement probe to the surface electrode because the surface electrode is miniaturized.
[0012]
Accordingly, a main object of the present invention is to provide a piezoelectric actuator capable of accurately and easily grasping the piezoelectric characteristics of a piezoelectric displacement portion without damaging a surface electrode, and to provide an ink jet recording head including the same. .
[0013]
It is another object of the present invention to accurately and easily grasp the piezoelectric characteristics of a piezoelectric displacement portion in a short time without damaging a surface electrode even in a piezoelectric actuator having a plurality of piezoelectric displacement portions. And an ink jet recording head provided with the same.
[0014]
Still another object of the present invention is to provide a piezoelectric actuator capable of accurately attaching a measurement probe to an electrode even if the piezoelectric actuator has a high degree of integration, and an ink jet recording head provided with the piezoelectric actuator.
[0015]
It is still another object of the present invention to provide a method for adjusting the piezoelectric characteristics and a method for adjusting the ink ejection amount, which can accurately and easily adjust the piezoelectric characteristics of the piezoelectric displacement unit.
[0016]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above problems, and as a result, the capacitance value between the surface electrode and the common electrode is different from the inspection electrode provided on the surface of the piezoelectric ceramic layer separately from the surface electrode. It has been found that the common electrode has a high correlation with the capacitance value between the common electrodes. Based on this finding, the present inventors have further studied and found that even if the measurement probe is not directly measured by attaching the measurement probe to the surface electrode and directly measuring the capacitance between the surface electrode and the common electrode, the inspection is performed. The present inventors have found a new fact that the piezoelectric characteristics of the piezoelectric actuator can be accurately and easily grasped by measuring the capacitance between the electrodes for use and the common electrode, and have completed the present invention.
[0017]
That is, the piezoelectric actuator of the present invention has the following configuration.
(1) A piezoelectric actuator in which a common electrode and a piezoelectric ceramic layer are laminated on a diaphragm in this order, and further a surface electrode is laminated on a part of the surface of the piezoelectric ceramic layer to form a piezoelectric displacement portion. A piezoelectric actuator, wherein an inspection electrode for inspecting piezoelectric characteristics of the piezoelectric displacement portion is provided on a surface of a piezoelectric ceramic layer.
(2) The piezoelectric actuator according to (1), wherein a plurality of the surface electrodes are formed on a surface of the piezoelectric ceramic layer.
(3) The piezoelectric actuator according to (1) or (2), wherein a surface area of the inspection electrode is larger than a surface area of the surface electrode.
(4) The piezoelectric actuator according to any one of (1) to (3), wherein a mark indicating an inspection result of the piezoelectric characteristic is attached to a surface of the piezoelectric ceramic layer.
(5) The piezoelectric actuator according to (4), wherein the inspection electrodes are provided at a plurality of mutually separated locations on the surface of the piezoelectric ceramic layer.
(6) The piezoelectric actuator according to (5), wherein the inspection electrodes are provided at four corners of the rectangular piezoelectric ceramic layer.
(7) The piezoelectric actuator according to any one of (1) to (6), wherein the thickness of the piezoelectric ceramic layer is 100 μm or less.
[0018]
The piezoelectric actuator of the present invention is particularly suitable for an ink jet recording head. That is, the inkjet recording head of the present invention has the following configuration.
(8) The piezoelectric actuator according to any one of (1) to (7), wherein a plurality of the surface electrodes are formed on the surface of the piezoelectric ceramic layer, a flow in which a plurality of ink channels having ink ejection holes are arranged. An ink jet recording head, wherein a position of an ink flow path and the surface electrode is aligned on a path member.
[0019]
The method for adjusting the piezoelectric characteristics and the method for adjusting the ink ejection amount according to the present invention have the following configurations.
(9) A method for adjusting the piezoelectric characteristics of the piezoelectric actuator according to any one of (1) to (7), wherein a method is provided between the inspection electrode and the common electrode facing each other via the piezoelectric ceramic layer. A method for adjusting piezoelectric characteristics, comprising measuring capacitance and controlling a voltage applied between the surface electrode and the common electrode based on the inspection result to adjust the piezoelectric characteristics.
(10) The method for adjusting an ink ejection amount in an ink jet recording head according to (8), wherein a capacitance between the inspection electrode and the common electrode facing each other via the piezoelectric ceramic layer is measured. A method for controlling the voltage applied between the surface electrode and the common electrode based on the inspection result to adjust the piezoelectric characteristics to thereby adjust the ink discharge amount.
[0020]
According to the piezoelectric actuator described in (1), it is not necessary to attach a measurement probe to the surface electrode, and the piezoelectric characteristics of the piezoelectric actuator can be grasped using the inspection electrode. Can be prevented from sticking.
[0021]
According to the piezoelectric actuator described in the above (2), even in the case of a highly integrated piezoelectric actuator having a plurality of surface electrodes formed thereon, the capacitance values of the plurality of piezoelectric displacement portions are set on the surface of the piezoelectric ceramic layer. Since there is a high correlation with the capacitance value between the provided inspection electrode and the common electrode, the capacitance between the inspection electrode and the common electrode can be measured without directly measuring the capacitance of the plurality of piezoelectric displacement portions. By measuring the capacitance, the piezoelectric characteristics of the piezoelectric actuator can be accurately and easily grasped in a short time without damaging the surface electrode.
[0022]
According to the piezoelectric actuator described in (3), since the inspection electrode having a larger surface area than the surface electrode is provided, even if the integration degree of the piezoelectric actuator is high, the measurement probe can be accurately attached to the inspection electrode. Can be. Thus, the piezoelectric characteristics of the piezoelectric actuator can be accurately inspected.
[0023]
According to the piezoelectric actuator described in the above (4), after the piezoelectric characteristics are inspected using the inspection electrode, a mark indicating the inspection result is attached to the surface of the piezoelectric ceramic layer, so that the mark is It can be used as a guide when adjusting the characteristics.
[0024]
According to the piezoelectric actuator described in the above (5), since the inspection electrodes are provided at a plurality of positions separated from each other on the surface of the piezoelectric ceramic layer, the inspection accuracy of the piezoelectric characteristics is further improved.
[0025]
According to the piezoelectric actuator described in the above (6), by arranging the inspection electrodes in the four corners of the piezoelectric ceramic layer, that is, in the dead space of the piezoelectric ceramic layer, the arrangement of the surface electrodes is not hindered and the size and size of the piezoelectric actuator can be reduced. There is no adverse effect on high integration, and the space can be used effectively. Also, if there is a large amount of blank space other than the portion where the surface electrodes are arranged, warpage tends to occur after firing, but by arranging the inspection electrodes in the four corner blanks, warpage can be suppressed. Also, the dimensional accuracy of the piezoelectric actuator is improved.
[0026]
According to the piezoelectric actuator described in (7), the piezoelectric actuator can be reduced in size and thickness, and a large displacement can be obtained with a small voltage. Also, by applying this piezoelectric actuator to an ink jet recording head, a high resolution ink jet printer can be obtained.
[0027]
According to the ink jet recording head described in (8), since the piezoelectric actuator whose variation in the piezoelectric characteristics is grasped by the inspection is provided, it is possible to adjust the ink ejection amount based on the inspection result.
[0028]
According to the method for adjusting the piezoelectric characteristics described in (9) and the method for adjusting the ink ejection amount described in (10), the piezoelectric characteristics and the ink ejection amount can be adjusted accurately and easily without damaging the surface electrode. be able to. Further, according to the adjustment method, it is possible to easily adjust the piezoelectric characteristics and the ink ejection amount in a short time.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a piezoelectric actuator and an inkjet recording head according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing an ink jet recording head provided with the piezoelectric actuator of the present embodiment, and FIG. 2 is a sectional view showing the ink jet recording head.
[0030]
As shown in FIGS. 1 and 2, the piezoelectric actuator 7 includes a common electrode 6 and a piezoelectric ceramic layer 2 b laminated in this order on a vibration plate 2 a, and the surface electrode 3 is formed on a part of the surface of the piezoelectric ceramic layer 2 b. A plurality of piezoelectric displacement parts 8 are formed by two-dimensionally arranging a plurality of parts at intervals. The plurality of surface electrodes 3 are each independently connected to an external electronic control circuit. The common electrode 6 is connected to the extraction electrode 4 via a via electrode (not shown) so that the potential is stabilized. The extraction electrode 4 is connected to the ground potential. The piezoelectric displacement section 8 is displaced by applying a voltage between the surface electrode 3 and the common electrode 6.
[0031]
The ink jet recording head 10 laminates the piezoelectric actuator 7 on the flow path member 11 in which the plurality of ink flow paths 11a having the ink discharge holes 11b are arranged by aligning the positions of the ink flow path 11a and the surface electrode 3. It was done. Each ink channel 11a is separated by a partition 11c.
[0032]
An inspection electrode 5 for inspecting the piezoelectric characteristics of the piezoelectric displacement section 8 is provided on the piezoelectric ceramic layer 2b. The inspection electrodes 5 are arranged at four corners on the rectangular piezoelectric ceramic layer 2b. The surface area of the inspection electrode 5 is preferably larger than the surface area of the surface electrode 3, and is preferably about 2 to 5 times larger.
[0033]
In the piezoelectric actuator 10 of the present invention, after the capacitance between the inspection electrode 5 and the common electrode 6 is measured, a mark 9 indicating the inspection result is provided on the piezoelectric ceramic layer 2b. The mark 9 is provided with an inspection result inspected by the four inspection electrodes 5. The inspection result attached to the mark 9 is not particularly limited as long as the inspection result can be discriminated. For example, the measured capacitance value may be attached as it is, and a symbol that is ranked according to the inspection result may be used. (For example, A, B, C,...). In addition, as the inspection result attached to the mark 9, the inspection results inspected by the four inspection electrodes 5 may be respectively applied separately, but the four measured capacitance values are averaged, and the average value is obtained. Alternatively, a symbol ranked according to the average value may be given. The means for providing the mark 9 on the piezoelectric ceramic layer 2b can be printed with, for example, UV ink.
[0034]
Based on the inspection result given to the mark 9, the voltage applied between the surface electrode 3 and the common electrode 6 is controlled by, for example, IC control or the like, so that the piezoelectric characteristics can be adjusted for each piezoelectric actuator 7. . Thereby, the ink ejection amount of the inkjet recording head 10 can be adjusted.
[0035]
As a material of the piezoelectric ceramic layer 2b, for example, at least one selected from the group consisting of lead zirconate titanate (PZT type), lead magnesium niobate (PMN type), and lead nickel niobate (PNN type) is used as a main component. Piezoelectric ceramics are preferred. The thickness of the piezoelectric ceramic layer 2b is not particularly limited, but is preferably 100 μm or less, preferably 50 μm or less, and more preferably 10 to 30 μm.
[0036]
The vibration plate 2a may have a high insulating property, but is preferably a piezoelectric material, particularly preferably a material having substantially the same coefficient of thermal expansion as the piezoelectric ceramic layer 2b, and substantially the same as the piezoelectric ceramic layer 2b. More preferably, the composition is Thereby, simultaneous firing becomes possible, and it becomes easy to prevent warpage and distortion from occurring due to thermal stress generated during firing due to a difference in thermal expansion. Further, the diaphragm 2a may be a single layer, but is preferably a laminate in order to control the thickness and suppress the variation in composition and characteristics after sintering. The thickness of the diaphragm 2a is not particularly limited, but is preferably 100 μm or less, preferably 50 μm or less, and more preferably 10 to 30 μm. The total thickness of the piezoelectric actuator 7 is 200 μm or less, preferably 100 μm or less, and more preferably 30 to 60 μm.
[0037]
Further, the porosity of the diaphragm 2a and the piezoelectric ceramic layer 2b is preferably 1% or less, particularly 0.8% or less, and more preferably 0.5% or less, so that penetration of a liquid such as ink can be effectively prevented. This is preferable because ink leakage can be reduced.
[0038]
The material of the common electrode 6 is preferably Ag, Pd, Pt, Rh, Au, or a single or a combination of two or more Ni-based materials, and more preferably an Ag-Pd-based alloy. The piezoelectric ceramic layer 2a and the common electrode 6 are formed by simultaneous firing. The thickness of the common electrode 6 is preferably such that it has conductivity and does not hinder the displacement, and is 0.5 to 8 μm, preferably 1 to 3 μm.
[0039]
As the material of the surface electrode 3 and the inspection electrode 5, for example, the same metal as the above-mentioned common electrode 6 can be used, but it is particularly preferable to use Au which is excellent in electric resistance and corrosion resistance. The thickness of the surface electrode 3 and the inspection electrode 5 is 1 to 10 μm, preferably 2 to 5 μm. In particular, it is preferable that the surface electrode 3 and the inspection electrode 5 have the same material and thickness in terms of improving inspection accuracy. As the material of the extraction electrode 4, the same metal as that of the above-described surface electrode 3 can be used.
[0040]
Next, a method for manufacturing the piezoelectric actuator 7 will be described.
(A) First, after forming a required number of green sheets using the above-described piezoelectric ceramic powder, through holes are formed in the green sheets.
(B) Next, a conductor serving as a via electrode is filled in the green sheet having the through holes formed thereon by screen printing, and a common electrode pattern is formed on substantially the entire surface of the green sheet.
(C) Next, a green sheet is laminated on the green sheet on which the via electrode pattern and the common electrode pattern are formed so as to sandwich the common electrode pattern to form a laminate.
(D) Further, after cutting the laminate into a predetermined shape, the laminate is fired at about 900 to 1100 ° C. to form a piezoelectric actuator body.
(E) Finally, a conductive paste is printed on the surface of the piezoelectric actuator body to form an inspection electrode pattern, a surface electrode pattern, and an extraction electrode pattern at predetermined positions, and baked at about 600 to 850 ° C. Thereby, the piezoelectric actuator 7 can be obtained. In addition, the surface electrode, the extraction electrode, and the inspection electrode can be simultaneously fired with the piezoelectric ceramic layer, the common electrode, and the diaphragm.
[0041]
Next, a method for manufacturing the inkjet recording head 10 will be described.
The flow path member 11 is obtained by a rolling method or the like, and the ink discharge holes 11b and the ink flow paths 11a are provided in a predetermined shape by etching. The flow path member 11 is desirably formed of at least one selected from the group of Fe—Cr, Fe—Ni, and WC—TiC, and is preferably made of a material having excellent corrosion resistance to ink. Desirably, the Fe-Cr system is more preferable.
[0042]
The piezoelectric actuator 7 and the flow path member 11 can be laminated and bonded via an adhesive layer, for example. As the adhesive layer, a well-known adhesive layer can be used. However, in order not to affect the piezoelectric actuator 7 and the flow path member 11, an epoxy resin, a phenol resin, and a polyphenylene ether having a thermosetting temperature of 130 to 250 ° C. It is preferable to use at least one thermosetting resin-based adhesive selected from the group of resins. By heating to the thermosetting temperature using such an adhesive layer, the piezoelectric actuator 7 and the flow path member 11 can be heated and joined, whereby the ink jet recording head 10 can be obtained.
[0043]
In the above embodiment, the piezoelectric actuator mounted on the ink jet recording head having a plurality of piezoelectric displacement portions has been described as an example. However, the present invention is directed to positioning of various devices by generating minute displacement. The present invention can be applied to various piezoelectric actuators used for pressure and pressure.
[0044]
Further, in the above embodiment, the case where the test electrodes are provided at the four corners using the rectangular piezoelectric ceramic layer has been described, but the shape of the piezoelectric ceramic layer, and the arrangement location and number of the test electrodes are particularly limited. Not something.
[0045]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
Example 1
Two PZT green sheets having a thickness of 50 μm after firing were prepared. A surface electrode pattern and a common electrode pattern both made of Ag-Pd paste were formed on each green sheet by screen printing. The green sheet on which the surface electrode pattern was formed was previously perforated and filled with a conductor so that the extraction electrode and the common electrode could be electrically connected. Further, an inspection electrode pattern of an Ag-Pd paste was printed and formed at the four corners of the green sheet on which the surface electrode was formed such that the surface area of each inspection electrode pattern was three times the surface electrode pattern. The two green sheets were laminated and fired at 1100 ° C., thereby obtaining a piezoelectric actuator as shown in FIGS.
[0046]
In the obtained piezoelectric actuator, the capacitance value between each surface electrode and the common electrode was measured, and the average value was calculated. Similarly, the capacitance value between each test electrode and the common electrode was measured, and the average value was calculated. As a result, it was found that the average value of the capacitance between the surface electrode and the common electrode had a high correlation with the average value of the capacitance between the inspection electrode and the common electrode.
[0047]
Next, after the above-described piezoelectric actuator was laminated and adhered on the flow path member to produce an ink jet recording head as shown in FIGS. 1 and 2, the correlation between the ink ejection amount and the capacitance value was examined. As a result, it was found that there is also a high correlation between the average value of the capacitance between the inspection electrode and the common electrode and the ink ejection amount. Therefore, it was found that the variation in the piezoelectric characteristics of the piezoelectric actuator and the variation in the ink ejection amount of the inkjet recording head can be inspected by the capacitance value between the inspection electrode and the common electrode.
[0048]
Example 2
The inspection results obtained in Example 1 were classified into ranks, and marks indicating the corresponding ranks were printed on the piezoelectric ceramic layer of the piezoelectric actuator obtained in Example 1 using UV ink. Next, the printed mark was read by a CCD camera, and based on the read data, the voltage applied between the surface electrode and the common electrode was adjusted to one of the following AC to adjust the piezoelectric characteristics. . Next, the adjusted voltage was applied to measure the ink ejection amount of the inkjet recording head.
<Rank classification>
A: 18V driveable capacity B: 20V driveable capacity C: 22V driveable capacity
Comparative Example In the same manner as in Example 2, except that the piezoelectric characteristics were not adjusted based on the inspection results obtained in Example 1 and a voltage used when it was assumed that the piezoelectric characteristics were appropriate was applied. The ink ejection amount was measured.
[0050]
In the comparative example, the ink ejection amount varied from the proper value by about 15%, whereas in the second embodiment, the ink ejection amount almost equal to the proper value was obtained.
[0051]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the piezoelectric actuator of this invention, it is not necessary to attach a probe for a measurement to a surface electrode, it can grasp | ascertain the piezoelectric characteristic of a piezoelectric actuator using an electrode for a test | inspection, Therefore, it is possible to obtain a high quality piezoelectric actuator.
[0052]
According to the present invention, even in a highly integrated piezoelectric actuator in which a plurality of surface electrodes are formed, the piezoelectric characteristics of the piezoelectric actuator can be accurately and easily grasped in a short time without damaging the surface electrodes. This has the effect.
[0053]
When the surface area of the electrode for inspection in the present invention is larger than the surface area of the surface electrode, the probe for measurement can be accurately attached to the electrode for inspection. There is an effect that inspection can be performed.
[0054]
When a mark indicating the inspection result of the piezoelectric characteristic is attached to the surface of the piezoelectric ceramic layer in the present invention, the mark can be used as a guide when adjusting the piezoelectric characteristic, so that the mark can be accurately and easily made. There is an effect that variation in piezoelectric characteristics can be adjusted.
[0055]
In the present invention, when the inspection electrodes are provided at a plurality of mutually separated locations on the surface of the piezoelectric ceramic layer, the inspection accuracy of the piezoelectric characteristics is further improved, so that the variation in the piezoelectric characteristics can be further reduced. effective.
[0056]
When the test electrodes are provided at the four corners of the rectangular piezoelectric ceramic layer according to the present invention, the arrangement of the surface electrodes is not hindered, and there is no adverse effect on miniaturization and high integration. In addition, it is possible to effectively use a space, suppress occurrence of warpage, and improve the dimensional accuracy of the piezoelectric actuator.
[0057]
When the thickness of the piezoelectric ceramic layer in the present invention is 100 μm or less, there is an effect that the size and thickness of the piezoelectric actuator can be reduced and a large displacement can be obtained with a small voltage. Further, by applying this piezoelectric actuator to an ink jet recording head, a high resolution ink jet printer can be obtained.
[0058]
ADVANTAGE OF THE INVENTION According to the inkjet recording head of this invention, there exists an effect that the dispersion | variation of an ink discharge amount can be adjusted accurately and easily.
[0059]
According to the adjustment method of the present invention, it is possible to adjust the piezoelectric characteristics and the ink ejection amount without damaging the surface electrode, and thus it is possible to improve the quality of the piezoelectric actuator and the ink jet recording head. Further, according to the adjustment method, it is possible to adjust the piezoelectric characteristics and the ink discharge amount accurately and easily in a short time, so that there is an effect that the manufacturing cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an ink jet recording head provided with a piezoelectric actuator of the present invention.
FIG. 2 is a sectional view showing an ink jet recording head provided with the piezoelectric actuator of the present invention.
FIG. 3 is a sectional view showing a conventional ink jet recording head.
[Explanation of symbols]
2a Vibration plate 2b Piezoelectric ceramic layer 3 Surface electrode 5 Inspection electrode 6 Common electrode 7 Piezoelectric actuator 8 Piezoelectric displacement part 9 Mark 10 Ink jet recording head 11 Flow path member 11a Ink flow path 11b Ink ejection hole 11c Partition wall

Claims (10)

A piezoelectric actuator in which a common electrode and a piezoelectric ceramic layer are laminated in this order on a vibration plate, and further a surface electrode is laminated on a part of the surface of the piezoelectric ceramic layer to form a piezoelectric displacement portion. A piezoelectric actuator, characterized in that an inspection electrode for inspecting the piezoelectric characteristics of the piezoelectric displacement section is provided on the surface of the piezoelectric actuator. The piezoelectric actuator according to claim 1, wherein a plurality of the surface electrodes are formed on a surface of the piezoelectric ceramic layer. The piezoelectric actuator according to claim 1, wherein a surface area of the inspection electrode is larger than a surface area of the surface electrode. The piezoelectric actuator according to any one of claims 1 to 3, wherein a mark indicating a test result of the piezoelectric characteristic is provided on a surface of the piezoelectric ceramic layer. The piezoelectric actuator according to claim 4, wherein the inspection electrodes are provided at a plurality of mutually separated locations on the surface of the piezoelectric ceramic layer. 6. The piezoelectric actuator according to claim 5, wherein the inspection electrodes are provided at four corners of the rectangular piezoelectric ceramic layer. The piezoelectric actuator according to claim 1, wherein the thickness of the piezoelectric ceramic layer is 100 μm or less. The piezoelectric actuator according to any one of claims 1 to 7, wherein a plurality of the surface electrodes are formed on the surface of the piezoelectric ceramic layer, on a flow path member on which a plurality of ink flow paths having ink ejection holes are arranged. An ink jet recording head, wherein the ink flow path and the front surface electrode are mounted so as to be aligned. A method for adjusting piezoelectric characteristics of the piezoelectric actuator according to any one of claims 1 to 7, wherein a capacitance between the inspection electrode and the common electrode facing each other via the piezoelectric ceramic layer is measured. And adjusting a piezoelectric characteristic by controlling a voltage applied between the surface electrode and the common electrode based on the inspection result. 9. The method for adjusting an ink ejection amount in an ink jet recording head according to claim 8, wherein a capacitance between the inspection electrode and the common electrode facing each other via the piezoelectric ceramic layer is measured. A method of controlling a voltage applied between the surface electrode and the common electrode to adjust a piezoelectric characteristic to thereby adjust an ink ejection amount.

Images