JP2000263777A - Laminated piezoelectric element and printer apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated piezoelectric element which accurately and correctly shifts and a printer apparatus which can discharge a correct amount of ink with use of the laminated piezoelectric element. SOLUTION: A laminated piezoelectric layer 10 having a piezoelectric substrate 20 and an internal electrode 30 alternately layered includes a first laminated piezoelectric area 10a which shifts in a predetermined direction A when a first voltage is impressed from outside and, a second laminated piezoelectric area 10b which shifts in a direction to negate a ringing component included in a shift amount of the first laminated piezoelectric area 10a when a second voltage corresponding to the ringing component included in the shift amount of the first laminated piezoelectric area 10a is impressed from outside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated piezoelectric element for controlling the amount of displacement of the laminated piezoelectric element and a printer using the same.

[0002]

2. Description of the Related Art FIG. 7 is a structural view showing an example of a conventional laminated piezoelectric element. A conventional laminated piezoelectric element 1 will be described with reference to FIG. The laminated piezoelectric element 1 in FIG. 7A has a piezoelectric substrate 2, internal electrodes 3, external terminals 4, 5, and the like.
The piezoelectric substrates 2 and the internal electrodes 3 are alternately stacked, and external terminals 4 and 5 are formed on both ends of the stacked piezoelectric substrates 2. The external terminal 4 is connected only to the plurality of first internal electrodes 3a, and the external terminal 5 is connected only to the plurality of second internal electrodes 3b. When the pulse voltage V is applied to the external terminals 4 and 5, the internal electrodes 3a and 3a having different polarities are provided.
b are alternately stacked.

As shown in FIG. 7B, when the external terminal 4 is connected to the positive terminal of a voltage supply unit (not shown) and the external terminal 5 is connected to the negative terminal of the voltage supply unit,
Forms a positive electrode region 1a, an inactive region 1b, and a negative electrode region 1c. The laminated piezoelectric element 1 is displaced in the direction of arrow A1 when a positive voltage is applied from the external terminal 4, and is displaced in the direction of arrow A2 when a negative voltage is applied. Note that inactive region 1
b is a region that does not displace even when either the positive voltage or the negative voltage is applied to the external terminal 4.

FIG. 8 is a circuit diagram for operating the laminated piezoelectric element 1, and an operation example of the laminated piezoelectric element 1 will be described with reference to FIGS. 7 and 8. FIG. In FIG. 8, the external terminal 4 is connected to the voltage supply unit 6, and the external terminal 5 is grounded. When the voltage supply unit 6 applies the pulse voltage V to the laminated piezoelectric element 1, the laminated piezoelectric element 1 shown in FIG. 6 is proportional to the magnitude of the pulse voltage V in the direction of arrow A in FIG. Is displaced.

[0005]

Incidentally, in order to perform printing at high speed, it is necessary to increase the speed at which ink is discharged, that is, the driving speed of the laminated piezoelectric element 10. To do so, it is necessary to drive the laminated piezoelectric element 10 with a pulse voltage V having a high frequency. However, when a high-frequency (resonant frequency) pulse voltage V is supplied to the laminated piezoelectric element 1, there is a problem that a ringing component Rp is generated in the displacement of the laminated piezoelectric element 1, as shown in FIG.

[0009] Specifically, FIG. 9 shows a difference in displacement amount (displacement amount-frequency characteristic) when a pulse voltage V having a different frequency is applied to the laminated piezoelectric element 1 with the same voltage magnitude. FIG. In FIG. 9, the resonance frequency of the laminated piezoelectric element 1 is, for example, 100 (kHz).
It is assumed that the resonance frequency is set in FIG.
This changes depending on the length L of the laminated piezoelectric element 1 shown in FIG. 9, it can be seen that as the frequency of the pulse voltage V approaches the resonance frequency (for example, 100 (kHz)), the displacement of the laminated piezoelectric element 1 increases. When the multilayer piezoelectric element 10 is driven by a high-frequency voltage near the resonance frequency, the displacement of the multilayer piezoelectric element 1 suddenly changes, so that the multilayer piezoelectric element 1 undergoes transient vibration (ringing).

If the ringing component Rp is included in the displacement of the laminated piezoelectric element 1, when the pulse voltage V rises, the displacement of the laminated piezoelectric element 1 becomes larger than a predetermined amount (overshoot), and the pulse voltage V becomes zero. Then, there is a problem that the displacement amount of the laminated piezoelectric element 1 becomes smaller than a predetermined amount (undershoot). When the laminated piezoelectric element 1 is used as an actuator for ejecting ink in an ink jet printer, for example, if the amount of displacement of the laminated piezoelectric element 1 includes the ringing component Rp, the ink ejected from the nozzle is There is a problem that the amount becomes larger (or smaller) than a predetermined amount, and a desired print result cannot be obtained. Therefore, when printing is performed using the laminated piezoelectric element 1, there is a problem that it is difficult to perform high-speed and clean printing.

Accordingly, the present invention solves the above-mentioned problems, and provides a laminated piezoelectric element capable of accurately and accurately displacing, and a printer apparatus capable of discharging an accurate amount of ink at high speed using the laminated piezoelectric element. It is intended to be.

[0009]

According to the first aspect of the present invention, there is provided a laminated piezoelectric element in which piezoelectric substrates and internal electrodes are alternately laminated, by applying a first voltage from the outside, The first laminated piezoelectric region is displaced in a predetermined direction, and a second voltage corresponding to a ringing component included in the displacement amount of the first laminated piezoelectric region is applied from the outside, whereby the first laminated piezoelectric region is displaced. This is achieved by a laminated piezoelectric element having a second laminated piezoelectric region that is displaced in a direction to cancel the ringing component included in the displacement amount.

According to another aspect of the present invention, there is provided an ink storage unit for storing ink, a nozzle for discharging ink supplied from the ink storage unit to an object,
A piezoelectric substrate in which piezoelectric substrates and electrodes are alternately laminated, and a laminated piezoelectric element that applies pressure to the ink containing section and ejects the ink from the nozzles; When a voltage is applied, the first laminated piezoelectric region displaced in a predetermined direction and a second voltage corresponding to a ringing component included in the amount of displacement of the first laminated piezoelectric region are externally applied. The present invention is achieved by a printer device having a second laminated piezoelectric region that is displaced in a direction to cancel a ringing component included in the displacement amount of the first laminated piezoelectric region.

According to the first and fifth aspects of the present invention, the laminated piezoelectric element is formed by the first laminated piezoelectric region displaced by the first voltage and the second laminated piezoelectric region displaced by the second voltage. I have. The second voltage is a voltage corresponding to a ringing component included in the displacement amount of the first laminated piezoelectric region, and the second laminated region is displaced in a direction to cancel the ringing component generated in the first laminated piezoelectric region. I do. Thus, even when the ringing component is included in the first multilayered piezoelectric region, the ringing component is canceled by the displacement amount of the second multilayered piezoelectric region. Output.

[0012]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that the embodiments described below are preferred specific examples of the present invention,
Although various technically preferable limits are given, the scope of the present invention is not limited to these modes unless otherwise specified in the following description.

FIG. 1 is a block diagram showing a preferred embodiment of the printer of the present invention. The printer 100 will be described with reference to FIG. Printer device 1 of FIG.
Reference numeral 00 denotes an inkjet printer, which includes an object feeding mechanism 110, a printer head moving unit 120, a printer head 130, and the like. Object feed mechanism 110
Are the object holder 111, the motor 112, the belt 113
And so on. The object holding unit 111 is formed, for example, in a cylindrical shape, and holds paper W as an object to be printed on the outer peripheral surface. The object holder 111 is mechanically connected to a motor 112 via a belt 113. When the motor 112 is driven, the object holding unit 111
Rotates in the direction of arrow R, and feeds the paper W in the direction of arrow R.

A printer head moving unit 120 and a printer head 130 are arranged on the outer peripheral surface side of the object holding unit 111. The printer head moving unit 120 includes a head holding unit 121, a motor 122, a guide 123, and the like. The head holding unit 121 is held by the guide 123. The head holding unit 121 moves in the arrow M direction along the guide 123 by driving of the motor 122.

A printer head 130 is arranged on the head holding section 121. FIG. 2 shows the printer head 13.
0, and the printer head 130 will be described with reference to FIG. Printer head 13 in FIG.
0 indicates two ink storage units 131a and 131, respectively.
b, conduits 132a, 132b, nozzles 133a, 133
b, including the laminated piezoelectric elements 10 and 10 as actuators. The ink storage section 131a stores, for example, an ink stock solution 140a of any one of the colors cyan, yellow and magenta.
The diluting liquid 140b for diluting the ink stock liquid 140a is stored in 31b.

The nozzles 133a and 133b are connected to the ink storage units 131a and 131b via conduits 132a and 132b.
And are connected respectively. Nozzles 133a, 133b
Are for discharging the stock ink 140a and the diluent 140b to the paper W, respectively. Also, the conduit 132a,
The laminated piezoelectric elements 10 and 10 are arranged below the 132b via the diaphragm 150, respectively. Multilayer piezoelectric element 1
0 and 10 are respectively connected to the voltage supply unit 80,
When the pulse voltage V is supplied from the voltage supply unit 80, the pulse voltage V is displaced by a predetermined amount in the direction of the arrow A according to the magnitude. That is, the laminated piezoelectric elements 10 and 10 are respectively
They are separately provided in order to adjust the discharge amounts of the diluent 40a and the diluent 140b.

Next, an example of the operation of the printer 100 will be described with reference to FIGS. First, in FIG. 1, the paper W is positioned at a predetermined position by the object feeding mechanism 110, and the printer head 130 is moved to the head moving unit 1.
20 moves the paper W to a predetermined position. And paper W
The amounts of the ink 140 and the diluent 140b shown in FIG.

Next, the voltage supply unit 80 applies the undiluted ink 140 to be ejected to the laminated piezoelectric elements 10 and 10, respectively.
a and a first voltage V1 of a magnitude corresponding to the diluent 140b
And a second voltage V2 described later is applied. Multilayer piezoelectric element 1
0 and 10 are displaced in the directions of arrows A based on the first voltage V1 and the second voltage V2, respectively, and apply pressure to the ink storage units 131a and 131b via the diaphragm 150.
Then, the undiluted ink 140a and the diluent 140b stored in the ink storage units 131a and 131b are supplied to the nozzle 1
33a and 133b, a predetermined amount is ejected, and the ink stock solution 14 is discharged.
The ink 140 obtained by mixing 0a and the diluent 140b is ejected to a predetermined position on the paper W, and printing is performed.

From the nozzles 133a and 133b, the ink 14
The ejection of 0 is performed by the operation of the head holding unit 120 in FIG.
For example, the operation is performed while the printer head 130 moves in the direction of arrow M. Thereby, printing is performed for a predetermined line on the paper W. Then, when printing for a predetermined line is completed, the object holding unit 111 is rotated in the direction of arrow R by the operation of the motor 112, and the paper W is fed by the predetermined line. After that, the printer head 130 further prints a predetermined line. By repeating this operation, printing for one page is performed.

FIG. 3 is a structural view showing a preferred embodiment of the laminated piezoelectric element of the present invention. The piezoelectric substrate element 10 will be described with reference to FIG. Piezoelectric substrate element 10 of FIG.
Has a piezoelectric substrate 20, internal electrodes 30, external terminals 40, and the like. The laminated piezoelectric element 10 shown in FIG. 3A has an operation in which, for example, an internal electrode 30 is formed on a piezoelectric substrate 20, the piezoelectric substrate 20 is disposed thereon, and the internal electrode 30 is further formed thereon. By repeating, the piezoelectric substrate 2
0 and the internal electrodes 30 are alternately stacked as shown. Here, the piezoelectric substrate 20 is mainly made of, for example, zirconate titanate, and is made of cobalt niobate zirconate titanate, bismuth niobate zirconate titanate, or barium titanate. The internal electrode 30 is made of, for example, platinum or palladium.

The internal electrode 30 includes a first internal electrode 31 and a second internal electrode 31.
It comprises an internal electrode 32 and a third internal electrode 33. First
The internal electrode 31 is formed on one end side 20a of the piezoelectric substrate 20, and the second internal electrode 32 is formed on the same plane as the first internal electrode 31 and on the other end side 20b of the piezoelectric substrate 20. . Then, the first internal electrode 31 and the second internal electrode 3
2 is electrically insulated. Also, the third internal electrode 33
Is a central area of the piezoelectric substrate 20 and overlaps with the first internal electrode 31 and the second internal electrode 32.
Is formed to exist. Then, the first internal electrode 31, the second internal electrode 32, and the third internal electrode 33
They are alternately stacked via the piezoelectric substrate 20. As a result, the piezoelectric substrate 20, the first internal electrode 31, and the third internal electrode 33 form the first laminated piezoelectric region 10a, and the piezoelectric substrate 2
0, the second internal electrode 32 and the third internal electrode 33 form the second laminated piezoelectric region 10b.

For example, one end 20 of the piezoelectric substrate 20
An external terminal 41 electrically connected only to the first internal electrode 31 is formed at a. For example, the other end 20b of the piezoelectric substrate 20 is electrically connected only to the second internal electrode 32 at the other end 20b. A second external terminal 42 is formed. further,
For example, a third external terminal 43 electrically connected to only the third internal electrode 33 is formed in a region between the first external terminal 41 and the second external terminal 42 in the stacked piezoelectric substrates 20. . First external terminal 41 and third external terminal 43
When a first voltage V1 described later is applied, the first laminated region 10a is displaced by a predetermined amount in the direction of arrow A, and a second voltage V2 described later is applied to the second external terminal 42 and the third external terminal 43. Then, the second laminated piezoelectric region 10b is displaced in the direction of arrow A by a predetermined amount.

Specifically, it is assumed that the first external terminal 41 and the second external terminal 42 are connected to the positive electrode side, and the third external terminal 43 is connected to the ground (earth) or the negative electrode side. At this time,
As shown in FIG. 3B, the first laminated piezoelectric region 10a includes a positive electrode region 11, an inactive region 12, and a negative electrode region 13.
Is formed. On the other hand, a negative electrode region 13, a positive electrode region 14, and an inactive region 15 are formed in the second laminated piezoelectric region 10b. When the first positive voltage V1 is applied from the first external terminal 41, the first laminated piezoelectric region 10a is displaced in the direction of arrow A1, and returns to the direction of arrow A2 when the first voltage V1 becomes zero. The second laminated piezoelectric region 10b is displaced in the direction of arrow A2 when the positive second voltage V2 is applied from the second external terminal 42, and returns in the direction of arrow A1 when the second voltage V2 becomes zero. The inactive region 12 (14) applies the first voltage V1 (second voltage V1) to the first external terminal 41 (second external terminal 42).
This area is not displaced even when 2) is applied.

FIG. 4 is a circuit diagram for operating the laminated piezoelectric element 10, and a driving circuit 200 for the laminated piezoelectric element 10 will be described with reference to FIG. 4 includes a voltage supply unit 80, a subtractor 81, a high-pass filter (hereinafter, referred to as “HPF”) 82, a DC offset voltage source 83, and the like. The voltage supply unit 80
It outputs a first voltage V1 for displacing the laminated piezoelectric region 10a, and includes a first external terminal 41 and an HPF 8
2 are electrically connected.

The subtractor 81 outputs a second voltage V2 for displacing the second laminated piezoelectric region 10b, and is electrically connected to the second external terminal 42. A direct current (DC) offset voltage source 83 is connected to the plus terminal on the input side of the subtractor 81, and the HP terminal is connected to the minus terminal.
F82 is connected. The HPF 82 has a function of passing only the ringing voltage Vr when the first voltage V1 and the ringing voltage Vr are input as described later.
The DC offset voltage source 83 is connected to the second laminated piezoelectric region 10b.
A predetermined offset voltage Vf is always applied to the second laminated piezoelectric region 10b so that a negative voltage is not applied to the second laminated piezoelectric region 10b. Therefore, the second laminated piezoelectric region 10b is displaced by a predetermined amount in the initial state. The third external terminal 43 is grounded (connected to the negative electrode side).

FIG. 5 is a graph showing a waveform diagram and the like when the laminated piezoelectric element 10 is displaced. An operation example of the laminated piezoelectric element 10 will be described with reference to FIGS. First, the voltage supply unit 80 of FIG.
In contrast, the first pulse voltage shown in FIG.
Supply voltage V1. The frequency of the first voltage V1 is set near the resonance frequency (high frequency) of the first laminated piezoelectric region 10a. Then, the first laminated piezoelectric region 10
In FIG. 5A, the displacement is made by a displacement including the ringing component Rp as shown in FIG. At this time, the first laminated piezoelectric region 10a generates a ringing voltage Vr by the ringing component Rp.

Then, the first voltage V1 and the ringing voltage V
r is input to an HPF (high pass filter) 84.
The HPF 84 cuts off the first voltage V1 component as a low frequency component and passes only the ringing voltage Vr as a high frequency component. The ringing voltage Vr is subtracted from the subtractor 8
1 is input to the minus terminal. Here, when the ringing voltage Vr is input to the minus terminal of the subtractor 81, the second voltage V2 becomes a voltage including an antiphase component of the ringing voltage Vr. Then, the subtracter 81 subtracts the ringing voltage Vr from the offset voltage Vf, and outputs the subtracted second voltage V2 (= Vf-Vr).

The second voltage V2 output from the subtractor 81
Is applied to the second laminated piezoelectric region 10b, and the second laminated piezoelectric region 10b is displaced by the second voltage V2 in the opposite phase direction (-Rp) to the ringing component Rp as shown in FIG. 5C. Then, the ringing component Rp generated in the first laminated piezoelectric region 10a is canceled by the displacement of the second laminated piezoelectric region 10b, and the same voltage corresponding to the applied first voltage V1 as shown in FIG. Is displaced by the displacement amount of.

According to the above embodiment, the two first piezoelectric elements 10 that can be displaced independently can be
The laminated piezoelectric region 10a and the second laminated piezoelectric region 10b are formed, and the second laminated piezoelectric region 10b is displaced in a direction to cancel the ringing component Rp of the first laminated piezoelectric region 10a. Therefore, the displacement amount of the multilayer piezoelectric element 10 as a whole corresponds to the pulse voltage V that does not include the ringing component, and the displacement amount of the multilayer piezoelectric element 10 can be accurately controlled.

When the laminated piezoelectric element 10 functions as an actuator of the ink jet printer 100, the ringing component Rp
Thus, it is possible to prevent extra ink from being ejected. Therefore, it is possible to increase the printing speed of the ink jet printer and obtain a clear printing result.

The embodiment of the present invention is not limited to the above embodiment. For example, in FIG. 2, the printer head 130 having two nozzles and the like for each color has been described. However, the actuator of the printer apparatus having a printer head having only one nozzle and the like for each color as shown in FIG. A piezoelectric element 10 can be used.

In FIG. 3, the first laminated piezoelectric region 1
0a and the second laminated piezoelectric region 10b are integrally formed, but as shown in FIG. 6, the two laminated piezoelectric devices 300 and 400 manufactured separately are combined to form the first laminated piezoelectric device 300. Laminated piezoelectric region 10a, laminated piezoelectric element 400
May function as the second laminated piezoelectric region 10b.

Further, referring to FIG.
By setting the polarization directions of the piezoelectric substrates 320 and 420 constituting the driving circuits 0 and 400 to be opposite to each other, the driving circuit 2 of FIG.
00 can be simplified. Specifically, the piezoelectric substrate 3
The polarization direction of the piezoelectric substrate 420 is changed to the direction of the arrow Z1.
Are formed so that the polarization direction of the arrow is in the direction of arrow Z2. Then, when the positive first voltage V1 is applied to the first external terminal 41, the laminated piezoelectric element 300 is displaced in the direction of arrow A1, and when the negative first voltage V1 is applied, the laminated piezoelectric element 300 is displaced in the direction of arrow A2. . On the other hand, when the positive second voltage V2 is applied to the second external terminal 42, the laminated piezoelectric element 400 is displaced in the direction of arrow A2, and when the negative second voltage V2 is applied, the laminated piezoelectric element 400 is displaced in the direction of arrow A2. I do. Accordingly, when the ringing voltage Vr that has passed through the HPF 82 is directly applied to the multilayered piezoelectric element 400, the multilayered piezoelectric element 400 is displaced in the opposite phase direction (−Rp) to the ringing component Rp. Therefore, FIG.
, And the DC offset voltage source 83 becomes unnecessary.

[0034]

As described above, according to the present invention,
It is possible to provide a laminated piezoelectric element that displaces accurately and accurately, and a printer device that can discharge an accurate amount of ink using the laminated piezoelectric element.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a preferred embodiment of a printer device of the present invention.

FIG. 2 is a configuration diagram illustrating a structure of a printer head in the printer of FIG. 1;

FIG. 3 is a configuration diagram showing a preferred embodiment of a laminated piezoelectric element of the present invention.

FIG. 4 is a diagram showing a drive circuit configured to operate the laminated piezoelectric element of the present invention.

FIG. 5 shows a first voltage and a first voltage in the multilayer piezoelectric element of the present invention.
FIG. 9 is a graph showing the displacement of a laminated piezoelectric region, the displacement of a second laminated piezoelectric region, and the displacement of a laminated piezoelectric element.

FIG. 6 is a configuration diagram showing another embodiment of the laminated piezoelectric element of the present invention.

FIG. 7 is a configuration diagram showing an example of a conventional laminated piezoelectric element.

FIG. 8 is a diagram showing a drive circuit for operating a conventional laminated piezoelectric element.

FIG. 9 is a graph showing the relationship between the amount of displacement and the frequency of a pulse voltage in a conventional laminated piezoelectric element.

FIG. 10 is a graph showing the amount of displacement of a conventional laminated piezoelectric element.

[Explanation of symbols]

10: laminated piezoelectric element, 20: piezoelectric substrate, 30
..Internal electrode, 31 first internal electrode, 32 second internal electrode, 33 third internal electrode, 40 external terminal, 41 first external terminal, 42 ..Second external terminal, 43... Third external terminal, 80... Voltage supply unit,
100 printer device, 110 target object feeding mechanism, 120 head moving unit, 130 printer head, 131a, 131b ink storage unit, 13
3a, 133b: nozzle, 200: drive circuit,
V1 ... first voltage, V2 ... second voltage, Rp ...
Ringing component.

Claims (5)

[Claims] 1. A laminated piezoelectric element in which piezoelectric substrates and internal electrodes are alternately laminated, wherein the first laminated piezoelectric region displaced in a predetermined direction by applying a first voltage from the outside, When a second voltage corresponding to a ringing component included in the displacement amount of the first laminated piezoelectric region is applied, the second laminated piezoelectric member is displaced in a direction to cancel the ringing component included in the displacement amount of the first laminated piezoelectric region. And a region. 2. The internal electrode, wherein: a first internal electrode formed at one end on the piezoelectric substrate; and an electrically insulated from the first internal electrode, the other end on the piezoelectric substrate. A second electrode, which is electrically insulated from the first internal electrode and the second internal electrode, and is a central region on the piezoelectric substrate, wherein the first internal electrode and the second A third internal electrode provided in a region overlapping with a region where the two electrodes are formed, wherein the first laminated piezoelectric region includes the piezoelectric substrate, the first internal electrode, and the third internal electrode. The second laminated piezoelectric region is formed by laminating the piezoelectric substrate and the second laminated piezoelectric region.
The multilayer piezoelectric element according to claim 1, wherein the internal electrode and the third internal electrode are formed by lamination. 3. The multilayer piezoelectric element according to claim 1, wherein the first internal electrode and the second internal electrode are electrically connected to a positive electrode, and the third internal electrode is grounded. 4. A polarization direction of a first piezoelectric substrate constituting the first laminated piezoelectric region is formed to be opposite to a polarization direction of a second piezoelectric substrate constituting the second laminated piezoelectric region. The multilayer piezoelectric element according to claim 1, wherein 5. An ink storage section for storing ink, a nozzle for discharging ink supplied from the ink storage section to an object, and a piezoelectric substrate and an electrode are alternately stacked,
A multilayer piezoelectric element that applies pressure to the ink storage section to eject the ink from the nozzle, wherein the multilayer piezoelectric element is displaced in a predetermined direction when a first voltage is applied from the outside. When the second voltage corresponding to the ringing component included in the displacement amount of the first laminated piezoelectric region is applied from the outside to the first laminated piezoelectric region, the displacement is included in the displacement amount of the first laminated piezoelectric region. A second laminated piezoelectric region that is displaced in a direction to cancel a ringing component.