JP4457516B2 - Droplet ejector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a droplet ejecting apparatus including a piezoelectric material plate for deforming at least a part of a wall surface of a liquid chamber.
[0002]
[Prior art]
As an ink jet head used in an ink jet type printer, one using a piezoelectric element is known. In such an ink jet head, a plate-like member (piezoelectric material plate) made of a piezoelectric material is used for a wall portion covering the ink pressure chamber. By applying a driving voltage to the piezoelectric material plate, the wall portion is deformed to induce pressure on the ink in the ink pressure chamber. As a result, ink is ejected from nozzles continuous to the ink pressure chamber.
[0003]
As a mode for driving and deforming such a piezoelectric material plate, there are usually a direct mode and a shear mode. In the direct mode, the direction of the electric field accompanying the application of the drive voltage matches the deformation direction of the piezoelectric material plate, and in the shear mode, the direction of the electric field is different from the deformation direction of the piezoelectric material plate.
[0004]
Among these modes, in the direct mode, the direction of the electric field when the drive voltage is applied matches the polarization direction of the piezoelectric material plate. For this reason, problems such as performance deterioration of the ink jet head due to weakening of polarization due to repeated application of the drive voltage do not occur. Also, there is a manufacturing advantage that the electrode itself for applying the drive voltage can be used when the piezoelectric material plate is polarized.
[0005]
[Problems to be solved by the invention]
However, in order to give a sufficient amount of deformation to eject ink to the wall of the ink pressure chamber, that is, the piezoelectric material plate, a high voltage is required for the drive voltage, and there is a problem that energy efficiency is poor.
[0006]
An object of the present invention is to provide a liquid droplet ejecting apparatus that can impart a sufficient amount of deformation to a piezoelectric material plate even when the driving voltage is low, and has good energy efficiency.
[0007]
[Means for Solving the Problems]
  The droplet ejecting apparatus of the present invention includes a piezoelectric material plate (1) for deforming at least a part of the wall surface of the liquid chamber (5), and the piezoelectric material plate (1) is deformed in a direct mode.ByIn a liquid droplet ejecting apparatus that ejects liquid droplets from a liquid chamber (5), the piezoelectric material plate (1)polarizationThe direction is inclined with respect to the surface direction of the piezoelectric material plate (1), and the voltage is applied to the piezoelectric material plate.Direction of polarizationPiezoelectric material plate (1)By deformation ofInject dropletsThe polarization direction of the piezoelectric material plate (1) and the direction of the electric field applied to the piezoelectric material plate (1) are substantially the same.It is characterized by that.
[0008]
  According to this droplet ejecting apparatus, the piezoelectric material platepolarizationSince the direction is inclined with respect to the surface direction of the piezoelectric material plate,Compared to the amount of deformation of the piezoelectric material plateSince the displacement width of the wall surface driven by the piezoelectric material plate can be increased,Even if the same drive voltage is appliedThus, it is possible to obtain a droplet ejecting apparatus with good energy efficiency.
  In this case, a common electrode can be used as an electrode used for polarization and an electrode used for driving. Furthermore, the applied electric field works efficiently due to the displacement of the piezoelectric material plate in the direct mode.
[0009]
  The droplet ejection device according to claim 2 is the droplet ejection device according to claim 1, wherein the piezoelectric material plate (1) includes a constant potential first electrode (2) and the piezoelectric material plate. And a second electrode (3) to which a voltage for deforming (1) is applied. The first electrode (2) and the second electrode (2) are viewed from a direction orthogonal to the plane direction. The electrode (3) is displacedIt is characterized by that.
[0013]
The polarization direction may be inclined at an angle range of 10 to 70 degrees with respect to the surface direction of the piezoelectric material plate (1).
[0014]
In this case, the displacement width of the wall surface driven by the piezoelectric material plate can be sufficiently increased compared to the deformation amount of the piezoelectric material plate.
[0015]
The piezoelectric material plate (1) has a pair of regions across substantially the center of the liquid chamber (5), and the deformation of each region when a voltage is applied may be in opposite directions.
[0016]
In this case, the displacement of the piezoelectric material plate can be increased even with the same driving voltage.
[0019]
Electrodes (2, 3) for applying an electric field to the piezoelectric material plate may be provided inside the piezoelectric material plate (1).
[0020]
In this case, it is possible to prevent the electrode from deteriorating due to the electrode coming into contact with the liquid in the liquid chamber.
[0021]
The piezoelectric material plate (1) may be configured by laminating a plurality of sheet-like piezoelectric materials (1a).
[0022]
In this case, an electrode can be easily formed inside the piezoelectric material plate.
[0023]
The electrodes (2, 3) may be formed on the surface of the piezoelectric material plate (1).
[0024]
In this case, the electrodes (2, 3) can be easily formed by using a printing method or the like.
[0025]
In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated embodiment.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
-First embodiment-
Hereinafter, a first embodiment in which a liquid droplet ejecting apparatus of the present invention is applied to an ink jet head will be described with reference to FIGS.
[0027]
FIG. 1 is a cross-sectional view showing a liquid droplet ejecting apparatus according to the first embodiment, FIG. 2 is a cross-sectional view showing a state where ink is filled in the liquid chamber of the liquid droplet ejecting apparatus according to the first embodiment, and FIG. FIG. 4 is a cross-sectional view showing a state where a drive voltage is applied, and FIG. 5 is a cross-sectional view showing a state where the application of the drive voltage is stopped.
[0028]
As shown in FIGS. 1 to 3, the droplet ejecting apparatus 100 according to the first embodiment is configured by stacking a plurality of (six in this example) green sheets (sheet-like piezoelectric material) 1 a. The material plate 1, the first electrode 2 provided inside the piezoelectric material plate 1, the second electrode 3 provided inside the piezoelectric material plate 1, and a plurality of through holes corresponding to the liquid chamber 5 Along with the formed first liquid chamber plate 6 and the piezoelectric material plate 1, a plurality of through holes corresponding to the liquid chamber 5 of the first liquid chamber plate 6 are closed to form the liquid chamber 5, A second liquid chamber plate 7 in which a through hole as an ink supply path 5b to the liquid chamber 5 and a through hole as an onk discharge path are formed corresponding to predetermined positions of the liquid chamber 4, and each liquid And a nozzle plate 9 in which a plurality of nozzles 8 corresponding to the chamber 5 are formed.
[0029]
As shown in FIGS. 1 to 3, the piezoelectric material plate 1, the first liquid chamber plate 6, the second liquid chamber plate 7, and the nozzle plate 9 are sequentially laminated to form a plurality of liquid chambers 5 having nozzles 8. Are formed in an array. The piezoelectric material plate 1 closes the through hole of the first liquid chamber plate 6 and constitutes a part of the wall surface of the liquid chamber 5. The piezoelectric material plate 1 is supported by the first liquid chamber plate 6 and deforms with the support position as a fulcrum.
[0030]
When a voltage is applied between the first electrode and the second electrode of the piezoelectric material plate 1 and the piezoelectric material plate 1 is deformed, a part of the ink stored in the liquid chamber 5 is transferred to the second liquid chamber. The ink is supplied to the nozzle 8 of the nozzle plate 9 through the through hole as the ink discharge path 5 a of the plate 7, and ink is ejected from the nozzle 8. On the other hand, an amount of ink corresponding to the amount of ejected ink is replenished to the liquid chamber 5 through a through hole serving as an ink supply path 5 b of the second liquid chamber plate 7.
[0031]
The first electrode 2 is provided corresponding to each liquid chamber 5 and is located at a support position of the piezoelectric material plate 1 supported by the liquid chamber plate 6. The first electrode 2 is configured by electrically connecting three-layer electrode patterns formed in the middle of the green sheet 1a. As shown in FIG. 1 and the like, the electrode pattern of the first electrode 2 is formed so that the area of the electrode pattern gradually decreases in the thickness direction of the piezoelectric material plate 1 from the lower side to the upper side in FIG.
[0032]
The second electrode 3 is provided corresponding to each liquid chamber 5, and is located at a substantially central portion of each liquid chamber 5. The second electrode 3 is configured by electrically connecting three-layer electrode patterns formed in the middle of the green sheet 1a. As shown in FIG. 1 and the like, the electrode pattern of the second electrode 3 is formed so that the area thereof increases sequentially from the lower side to the upper side in FIG. Further, the first electrode 2 is located generally on the lower side in FIG. 1, whereas the second electrode 3 is located on the upper side in FIG. 1 as a whole.
[0033]
In addition, the structure which mutually connects the electrode pattern which comprises the 1st electrode 2 and the 2nd electrode 3, and the structure which draws out each electrode can be selected arbitrarily.
[0034]
1 to 3, an arrow (indicated by a symbol “A” in FIG. 1) drawn inside the piezoelectric material plate 1 indicates the polarization direction of the piezoelectric material plate 1. As shown in each figure, the piezoelectric material plate 1 is polarized in a direction connecting the first electrode 2 and the second electrode 3.
[0035]
Next, the operation of ejecting droplets will be described with reference to FIGS.
[0036]
As shown in FIG. 2, the liquid chamber 5 is first filled with ink. At this time, both the first electrode 2 and the second electrode 3 are connected to the ground (0 V). Next, as shown in FIG. 4, a positive voltage is applied to the second electrode 3 while the first electrode 2 is connected to the ground. At this time, since the direction of the electric field generated between the first electrode 2 and the second electrode 3 coincides with the polarization direction of the piezoelectric material plate 1, the piezoelectric material plate 1 is polarized in a direct mode in the polarization direction. Deforms to extend in the direction. As shown in FIG. 4, as the piezoelectric material plate 1 is deformed, the region where the second electrode 3 is formed moves upward in FIG. 4, thereby increasing the volume of the liquid chamber 5 and increasing the volume. The amount of ink corresponding to is supplied from an ink tank which is an ink supply tank (not shown). Here, the deformation direction of the piezoelectric material plate 1 is opposite to each other across the substantial center of the liquid chamber 5 in which the second electrode 3 is formed.
[0037]
Next, when the potential of the second electrode 3 is returned to the ground (0 V) while the first electrode 2 is connected to the ground, the shape of the piezoelectric material plate 1 returns to the same state as in FIG. 2, and is shown in FIG. As described above, a predetermined amount of ink 10 is ejected from the liquid chamber 5 through the nozzle 8.
[0038]
As shown in FIGS. 1 to 5, in the liquid droplet ejecting apparatus 100 of the first embodiment, the polarization direction of the piezoelectric material plate 1, that is, the expansion and contraction direction of the piezoelectric material plate is the surface direction of the piezoelectric material plate 1 (FIGS. It is slightly inclined with respect to the left and right direction in FIG. Therefore, the displacement of the piezoelectric material plate 1 in the polarization direction can be easily transmitted as a change in the volume of the liquid chamber 5, and the piezoelectric material plate 1 is deformed in the polarization direction of the piezoelectric material plate 1 with reference to FIGS. The displacement width in the up and down direction, that is, the volume change of the liquid chamber 5 increases. Therefore, the amount of deformation in the polarization direction of the piezoelectric material plate 1 necessary for giving a constant volume change to the liquid chamber 5 can be reduced, and the required drive voltage can be reduced. As a result, in the droplet ejecting apparatus 100 of the first embodiment, it is possible to reduce the cost of the apparatus by reducing the driving voltage, and to improve the energy efficiency by reducing the energy required for ink ejection. be able to.
[0039]
Note that the displacement width can be sufficiently increased by setting the inclination of the expansion / contraction direction of the piezoelectric material plate 1 with respect to the surface direction of the piezoelectric material plate 1 in the range of 10 degrees to 70 degrees.
[0040]
Hereinafter, with reference to FIG. 1 and FIG. 3, the manufacturing method of the droplet ejecting apparatus 100 of the first embodiment will be described.
[0041]
The piezoelectric material plate 1 can be manufactured by laminating and baking a plurality of sheet-like piezoelectric materials. At this time, by printing the material (conductive paste) of the first electrode 2 and the second electrode 3 on the green sheet in a predetermined pattern, the first electrode 2 is simultaneously formed with the firing of the green sheet. And the 2nd electrode 3 is formed.
[0042]
Next, the piezoelectric material plate 1 is polarized by applying a DC voltage between the first electrode 2 and the second electrode 3. Specifically, the first electrode 2 is connected to a negative potential, the second electrode 3 is connected to a positive potential, and an electric field is generated between the first electrode 2 and the second electrode 3. 1 and polarization in the direction of the arrow shown in FIG.
[0043]
As shown in FIGS. 1 and 3, the first electrode 2 and the second electrode 3 are provided at positions shifted in the vertical direction in each figure as a whole, so that the polarization direction is the surface of the piezoelectric material plate 1. The direction is slightly inclined with respect to the direction. Further, since the electrode used for polarization and the electrode used for driving the piezoelectric material plate 1 are common, the direction of the electric field coincides with the polarization direction when the piezoelectric material plate 1 is driven.
[0044]
Next, the piezoelectric material plate 1, the first liquid chamber plate 6, the second liquid chamber plate 7, and the nozzle plate 9 are sequentially stacked, whereby the droplet ejecting apparatus 100 of the first embodiment is manufactured.
[0045]
Note that the order of the step of polarizing the piezoelectric material plate 1 and the step of laminating the piezoelectric material 1, the first liquid chamber plate 6, the second liquid chamber plate 7, and the nozzle plate 9 may be interchanged.
[0046]
-Second Embodiment-
Hereinafter, a second embodiment in which the liquid droplet ejecting apparatus of the present invention is applied to an ink jet head will be described with reference to FIG. In FIG. 6, the same elements as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
[0047]
In the droplet ejecting apparatus 200 according to the second embodiment, the first electrode 22 is provided corresponding to each liquid chamber 5 and is located at a support position of the piezoelectric material plate 21 supported by the liquid chamber plate 6. The first electrode 22 is configured by electrically connecting three-layer electrode patterns formed in the middle of the green sheet 1a. The electrode pattern of the first electrode 22 is formed so that its area increases sequentially from the lower side to the upper side in FIG. 6 with respect to the thickness direction of the piezoelectric material plate 21.
[0048]
In the liquid droplet ejecting apparatus 200 of the second embodiment, the second electrode 23 is provided corresponding to each liquid chamber 5, and is positioned at a substantially central portion of each liquid chamber 5. The second electrode 23 is configured by electrically connecting three-layer electrode patterns formed in the middle of the green sheet 1a. The electrode pattern of the second electrode 23 is formed so that the area of the electrode pattern gradually decreases from the lower side to the upper side in FIG. 6 with respect to the thickness direction of the piezoelectric material plate 21. Further, the first electrode 22 as a whole is located near the upper side of the piezoelectric material plate 21 in FIG. 6, whereas the second electrode 23 is located as a whole near the lower side of the piezoelectric material plate 21 in FIG. is doing.
[0049]
In addition, the structure which connects the electrode pattern which comprises the 1st electrode 22 and the 2nd electrode 23 mutually, and the structure which draws out each electrode can be selected arbitrarily.
[0050]
In FIG. 6, an arrow drawn inside the piezoelectric material plate 21 indicates the polarization direction of the piezoelectric material plate 21. As shown in FIG. 6, the piezoelectric material plate 21 is polarized in a direction connecting the first electrode 22 and the second electrode 23.
[0051]
Next, an operation for ejecting droplets will be described.
[0052]
First, the liquid chamber 5 is filled with ink, and as shown in FIG. 6, a positive voltage is applied to the second electrode 23 while the first electrode 22 is connected to the ground. At this time, since the direction of the electric field generated between the first electrode 22 and the second electrode 23 coincides with the polarization direction of the piezoelectric material plate 21, the piezoelectric material plate 21 extends in the direct mode in the polarization direction. It deforms as follows. As shown in FIG. 6, as the piezoelectric material plate 21 is deformed, the region where the second electrode 23 is formed moves downward in FIG. 6, and the volume of the liquid chamber 5 decreases. Therefore, as shown in FIG. 6, a predetermined amount of ink 10 is ejected from the liquid chamber 5 through the nozzle 8. Here, the deformation direction of the piezoelectric material plate 21 is opposite to each other across the substantial center of the liquid chamber 5 in which the second electrode 23 is formed.
[0053]
Further, by stopping the application of the voltage to the second electrode 23, the piezoelectric material plate 21 returns to the original state, and ink corresponding to the volume change amount of the liquid chamber 5 by the piezoelectric material plate 21 at this time is obtained. Replenished from the ink supply device 116.
[0054]
In the droplet ejecting apparatus 200 of the second embodiment, the polarization direction of the piezoelectric material plate 21, that is, the expansion / contraction direction of the piezoelectric material plate is slightly inclined with respect to the surface direction of the piezoelectric material plate 21. For this reason, the displacement width of the piezoelectric material plate 21 in the vertical direction in FIG. 6 is larger than the deformation amount of the piezoelectric material plate 21 in the polarization direction. Therefore, it is possible to reduce the amount of deformation of the piezoelectric material plate 21 in the polarization direction necessary for giving a constant volume change to the liquid chamber 5, and to reduce the necessary driving voltage. As a result, in the droplet ejecting apparatus 200 of the second embodiment, it is possible to reduce the cost of the apparatus by reducing the driving voltage, and to improve the energy efficiency by reducing the energy required for ink ejection. be able to.
[0055]
In manufacturing the droplet ejecting apparatus 200 according to the second embodiment, the same steps as those in the first embodiment can be used, and thus the description thereof is omitted.
[0056]
-Third embodiment-
Hereinafter, with reference to FIG. 7, a third embodiment in which the liquid droplet ejecting apparatus of the present invention is applied to an ink jet head will be described. In FIG. 7, the same elements as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
[0057]
In the droplet ejecting apparatus 300 of the third embodiment, the first electrode 32 is provided corresponding to each liquid chamber 5, and is positioned at the support position of the piezoelectric material plate 31 supported by the liquid chamber plate 6. The first electrode 32 is configured by electrically connecting two electrode patterns having the same pattern formed in the middle of the green sheet 1a.
[0058]
The second electrode 33 is provided corresponding to each liquid chamber 5, and is located at a substantially central portion of each liquid chamber 5. The second electrode 33 is configured by electrically connecting two electrode patterns having the same pattern formed in the middle of the green sheet 1a.
[0059]
The first electrode 32 is located generally on the lower side of the piezoelectric material plate 31 in FIG. 7, whereas the second electrode 33 is located on the entire upper side of the piezoelectric material plate 31 in FIG. Yes. However, as in the first embodiment, there is no change in the area of each electrode in the thickness direction of the piezoelectric material plate 31.
[0060]
In addition, the structure which connects the electrode pattern which comprises the 1st electrode 32 and the 2nd electrode 33 mutually, and the structure which draws out each electrode can be selected arbitrarily.
[0061]
In FIG. 7, an arrow drawn inside the piezoelectric material plate 31 indicates the polarization direction of the piezoelectric material plate 31. As shown in FIG. 7, the piezoelectric material plate 31 is polarized in a direction connecting the first electrode 32 and the second electrode 33.
[0062]
Next, an operation for ejecting droplets will be described.
[0063]
First, the liquid chamber 5 is filled with ink, and as shown in FIG. 7, a positive voltage is applied to the second electrode 33 while the first electrode 32 is connected to the ground. At this time, since the direction of the electric field generated between the first electrode 32 and the second electrode 33 coincides with the polarization direction of the piezoelectric material plate 31, the piezoelectric material plate 31 is polarized in the direct mode in the polarization direction. Deforms to extend in the direction. As shown in FIG. 7, as the piezoelectric material plate 31 is deformed, the region where the second electrode 33 is formed moves upward in FIG. 4, thereby increasing the volume of the liquid chamber 5 and increasing the ink supply device. The ink corresponding to the increase amount of the volume of the liquid chamber 5 is supplied from 116. Here, the deformation direction of the piezoelectric material plate 31 is opposite to each other across the substantial center of the liquid chamber 5 where the second electrode 33 is formed.
[0064]
Next, when the potential of the second electrode 33 is returned to the ground (0 V) while the first electrode 32 is connected to the ground, the shape of the piezoelectric material plate 31 returns to the initial flat state, A predetermined amount of ink is ejected from the liquid chamber 5.
[0065]
In the droplet ejecting apparatus 300 of the third embodiment, the polarization direction of the piezoelectric material plate 31, that is, the expansion / contraction direction of the piezoelectric material plate is slightly inclined with respect to the surface direction of the piezoelectric material plate 31. For this reason, the displacement width of the piezoelectric material plate 31 in the vertical direction in FIG. 7 is larger than the deformation amount of the piezoelectric material plate 31 in the polarization direction. Therefore, the amount of deformation in the polarization direction of the piezoelectric material plate 31 necessary for giving a constant volume change to the liquid chamber 5 can be reduced, and the required drive voltage can be reduced. As a result, in the droplet ejecting apparatus 300 of the third embodiment, it is possible to reduce the cost of the apparatus by reducing the driving voltage, and to improve the energy efficiency by reducing the energy required for ink ejection. be able to.
[0066]
In manufacturing the droplet ejecting apparatus 300 according to the third embodiment, the same steps as those in the first embodiment can be used, and thus the description thereof is omitted.
[0067]
-Fourth Embodiment-
Hereinafter, a fourth embodiment in which the liquid droplet ejecting apparatus of the invention is applied to an ink jet head will be described with reference to FIG. In FIG. 8, the same elements as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
[0068]
In the liquid droplet ejecting apparatus 400 of the fourth embodiment, the first electrode 42 is provided corresponding to each liquid chamber 5 and is located at a support position of the piezoelectric material plate 41 supported by the liquid chamber plate 6. The first electrode 42 is configured by electrically connecting two-layer electrode patterns formed in the middle of the green sheet 1a. The electrode pattern of the first electrode 42 is formed so that its area increases sequentially from the lower side to the upper side in FIG. 8 with respect to the thickness direction of the piezoelectric material plate 41.
[0069]
In the liquid droplet ejecting apparatus 400 of the fourth embodiment, the second electrode 43 is provided corresponding to each liquid chamber 5, and is positioned at a substantially central portion of each liquid chamber 5. The second electrode 43 is configured by electrically connecting three-layer electrode patterns formed in the middle of the green sheet 1a. The electrode pattern of the second electrode 43 is formed so that the area of the second electrode 43 gradually decreases in the thickness direction of the piezoelectric material plate 41 from the lower side to the upper side in FIG. Further, the first electrode 42 as a whole is located closer to the upper side of the piezoelectric material plate 41 in FIG. 8, whereas the second electrode 43 as a whole is located closer to the lower side of the piezoelectric material plate 41 in FIG. is doing.
[0070]
In addition, the structure which connects the electrode pattern which comprises the 1st electrode 42 and the 2nd electrode 43 mutually, and the structure which draws out each electrode can be selected arbitrarily.
[0071]
In FIG. 8, an arrow drawn inside the piezoelectric material plate 41 indicates the polarization direction of the piezoelectric material plate 41. As shown in FIG. 8, the piezoelectric material plate 41 is polarized in a direction connecting the first electrode 42 and the second electrode 43.
[0072]
As shown in FIG. 8, in the droplet ejecting apparatus 400 of the fourth embodiment, a notch 41a is formed in a part of the piezoelectric material plate 41 in the region where the second electrode 43 is formed. By forming such a notch 41a, the piezoelectric material plate 41 can be easily bent, and the volume change amount of the liquid chamber 5 when a driving voltage is applied can be increased.
[0073]
Next, an operation for ejecting droplets will be described.
[0074]
First, the liquid chamber 5 is filled with ink, and as shown in FIG. 8, a positive voltage is applied to the second electrode 43 while the first electrode 42 is connected to the ground. At this time, since the direction of the electric field generated between the first electrode 42 and the second electrode 43 coincides with the polarization direction of the piezoelectric material plate 41, the piezoelectric material plate 41 is deformed in the direct mode in the polarization direction. To do. As shown in FIG. 8, as the piezoelectric material plate 41 is deformed, the area in which the second electrode 43 is formed moves downward in FIG. 8, thereby reducing the volume of the liquid chamber 5. Therefore, as shown in FIG. 8, a predetermined amount of ink 10 is ejected from the liquid chamber 5 through the nozzle 8. Here, the deformation direction of the piezoelectric material plate 41 is opposite to each other across the substantial center of the liquid chamber 5 where the second electrode 43 is formed.
[0075]
In the droplet ejecting apparatus 400 of the fourth embodiment, the polarization direction of the piezoelectric material plate 41, that is, the expansion / contraction direction of the piezoelectric material plate 41 is slightly inclined with respect to the surface direction of the piezoelectric material plate 41, and the piezoelectric material A portion that does not contribute to the deformation of the plate 41 is cut away. For this reason, the displacement width of the piezoelectric material plate 41 in the vertical direction in FIG. 8 is larger than the deformation amount of the piezoelectric material plate 41 in the polarization direction. Therefore, the amount of deformation in the polarization direction of the piezoelectric material plate 41 required for giving a constant volume change to the liquid chamber 5 can be reduced, and the required driving voltage can be further reduced. As a result, in the droplet ejecting apparatus 400 of the fourth embodiment, it is possible to reduce the cost of the apparatus by reducing the driving voltage, and to improve the energy efficiency by reducing the energy required for ink ejection. be able to.
[0076]
In manufacturing the droplet ejecting apparatus 400 of the fourth embodiment, the same process as that of the first embodiment can be used. In order to form the notch 41a, an opening is formed in the green sheet 1a in advance according to the shape of the notch 41a, and such green sheets may be laminated and fired. Of course, the green sheets may be laminated without an opening, and then the notch 41a may be formed by machining or laser processing.
[0077]
-Fifth embodiment-
Hereinafter, a fifth embodiment in which the liquid droplet ejecting apparatus of the invention is applied to an ink jet head will be described with reference to FIG. In FIG. 9, the same elements as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
[0078]
As shown in FIG. 9, in the droplet ejecting apparatus 500 of the fifth embodiment, the first electrode 52 and the second electrode 53 correspond to each liquid chamber 5 on the surface of the piezoelectric material plate 51. Is provided. The piezoelectric material plate 51 is formed by integrally sintering a piezoelectric material.
[0079]
The first electrode 52 is provided between the first liquid chamber plate 6 and the piezoelectric material plate 51, and the piezoelectric material plate 51 is supported by the first liquid chamber plate 6 via the first electrode 52. . On the other hand, the second electrode 53 is located at a substantially central portion of each liquid chamber 5.
[0080]
In addition, the structure which pulls out the 1st electrode 52 and the 2nd electrode 53 can be selected arbitrarily.
[0081]
In FIG. 9, an arrow drawn inside the piezoelectric material plate 51 indicates the polarization direction of the piezoelectric material plate 51. As shown in FIG. 9, the piezoelectric material plate 51 is polarized in a direction connecting the first electrode 52 and the second electrode 53.
[0082]
Next, an operation for ejecting droplets will be described.
[0083]
First, ink is filled into the liquid chamber 5, and as shown in FIG. 9, a positive voltage is applied to the second electrode 53 while the first electrode 52 is connected to the ground. At this time, since the direction of the electric field generated between the first electrode 52 and the second electrode 53 coincides with the polarization direction of the piezoelectric material plate 51, the piezoelectric material plate 51 is in direct mode in the polarization direction. Deform. As shown in FIG. 9, as the piezoelectric material plate 51 is deformed, the region in which the second electrode 53 is formed moves upward in FIG. 9, thereby increasing the volume of the liquid chamber 5 and increasing the ink supply device. The ink corresponding to the volume increase amount of the liquid chamber 5 is supplied from 116. Here, the deformation direction of the piezoelectric material plate 51 is opposite to each other across the substantial center of the liquid chamber 5 where the second electrode 53 is formed.
[0084]
Next, when the potential of the second electrode 53 is returned to the ground (0 V) while the first electrode 52 is connected to the ground, the shape of the piezoelectric material plate 51 returns to the initial flat state, A predetermined amount of ink is ejected from the liquid chamber 5.
[0085]
In the droplet ejecting apparatus 500 of the fifth embodiment, the polarization direction of the piezoelectric material plate 51, that is, the expansion / contraction direction of the piezoelectric material plate is slightly inclined with respect to the surface direction of the piezoelectric material plate 51. For this reason, the displacement width of the piezoelectric material plate 51 in the vertical direction in FIG. 9 is larger than the deformation amount of the piezoelectric material plate 51 in the polarization direction. Therefore, it is possible to reduce the amount of deformation of the piezoelectric material plate 51 in the polarization direction necessary for giving a constant volume change to the liquid chamber 5, and to reduce the necessary driving voltage. As a result, in the droplet ejecting apparatus 500 of the fifth embodiment, it is possible to reduce the cost of the apparatus by lowering the driving voltage, and to improve the energy efficiency by reducing the energy required for ink ejection. be able to.
[0086]
Note that the first electrode 52 and the second electrode 53 in the droplet ejecting apparatus 500 of the fifth embodiment print the material of the first electrode 52 and the second electrode 53 on the surface of the piezoelectric material plate 51. It can be formed by patterning into a predetermined shape using a vapor deposition method. Of these, the first electrode 52 may be formed not on the surface of the piezoelectric material plate 51 but on the first liquid chamber plate.
[0087]
-Sixth Embodiment-
Hereinafter, with reference to FIG. 10, a sixth embodiment in which the liquid droplet ejecting apparatus of the invention is applied to an ink jet head will be described. In FIG. 10, the same elements as those of the fifth embodiment are denoted by the same reference numerals, and the description thereof is omitted.
[0088]
As shown in FIG. 10, in the droplet ejecting apparatus 600 of the sixth embodiment, the piezoelectric material plate 61 is formed by integrally sintering a piezoelectric material.
[0089]
As shown in FIG. 10, in the droplet ejecting apparatus 600 of the sixth embodiment, a first electrode 62 and a second electrode 63 are provided corresponding to each liquid chamber 5. The first electrode 62 includes a lead portion 62 a formed on the surface of the piezoelectric material plate 61 and a housing portion 62 b connected to the lead portion 62 a and housed inside the piezoelectric material plate 61. The second electrode 63 includes a lead part 63 a formed on the surface of the piezoelectric material plate 61 and a housing part 63 b connected to the lead part 63 a and housed inside the piezoelectric material plate 61.
[0090]
The lead portion 62a of the first electrode 62 is provided between the first liquid chamber plate 6 and the piezoelectric material plate 61, and the piezoelectric material plate 61 is supported by the first liquid chamber plate 6 via the lead portion 62a. Is done. On the other hand, the second electrode 63 is located at a substantially central portion of each liquid chamber 5.
[0091]
In addition, the structure which pulls out the 1st electrode 62 and the 2nd electrode 63 can be selected arbitrarily.
[0092]
In FIG. 10, an arrow drawn inside the piezoelectric material plate 61 indicates the polarization direction of the piezoelectric material plate 61. As shown in FIG. 10, the piezoelectric material plate 61 is polarized in a direction connecting the first electrode 62 and the second electrode 63.
[0093]
Next, an operation for ejecting droplets will be described.
[0094]
First, ink is filled into the liquid chamber 5, and as shown in FIG. 10, a positive voltage is applied to the second electrode 63 while the first electrode 62 is connected to the ground. At this time, since the direction of the electric field generated between the first electrode 62 and the second electrode 63 coincides with the polarization direction of the piezoelectric material plate 61, the piezoelectric material plate 61 is in direct mode in the polarization direction. Deforms to stretch. As shown in FIG. 10, as the piezoelectric material plate 61 is deformed, the region in which the second electrode 63 is formed moves upward in FIG. 10 to increase the volume of the liquid chamber 5 and supply ink. Is done. Here, the deformation direction of the piezoelectric material plate 61 is opposite to each other across substantially the center of the liquid chamber 5 in which the second electrode 63 is formed.
[0095]
Next, when the potential of the second electrode 63 is returned to the ground (0 V) while the first electrode 62 is connected to the ground, the shape of the piezoelectric material plate 61 returns to the initial flat state, A predetermined amount of ink is ejected from the liquid chamber 5.
[0096]
In the droplet ejecting apparatus 600 of the sixth embodiment, the polarization direction of the piezoelectric material plate 61, that is, the expansion / contraction direction of the piezoelectric material plate is slightly inclined with respect to the surface direction of the piezoelectric material plate 61. For this reason, the displacement width of the piezoelectric material plate 61 in the vertical direction in FIG. 10 is larger than the deformation amount of the piezoelectric material plate 61 in the polarization direction. Therefore, the amount of deformation in the polarization direction of the piezoelectric material plate 61 necessary for giving a constant volume change to the liquid chamber 5 can be reduced, and the required drive voltage can be reduced. As a result, in the droplet ejecting apparatus 600 of the sixth embodiment, it is possible to reduce the cost of the apparatus by reducing the driving voltage, and to improve the energy efficiency by reducing the energy required for ink ejection. be able to.
[0097]
Note that the accommodating portion 62b of the first electrode 62 and the accommodating portion 63b of the second electrode 63 in the droplet ejecting apparatus 600 of the sixth embodiment form, for example, a notch in the piezoelectric material plate 61. It can be formed by filling the notch with an electrode material. Further, the lead portion 62a of the first electrode 62 and the lead portion 63a of the second electrode 63 can be formed by patterning an electrode material on the surface of the piezoelectric material plate 61 into a predetermined shape using printing or vapor deposition.
[0098]
-Seventh embodiment-
Hereinafter, with reference to FIG. 11, a seventh embodiment in which the liquid droplet ejecting apparatus of the invention is applied to an ink jet head will be described. In FIG. 11, the same elements as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
[0099]
In the liquid droplet ejecting apparatus 700 of the seventh embodiment, in addition to the first electrode 2 and the second electrode 3 similar to the liquid droplet ejecting apparatus 100 of the first embodiment, the liquid ejecting apparatus 700 corresponds to each liquid chamber 5. A third electrode 74 is provided. As shown in FIG. 11, the third electrode 74 is configured by electrically connecting five layers of electrode patterns formed in the middle of the green sheet 1a. These electrode patterns are sequentially shifted in the plane direction of the piezoelectric material plate 71, and equivalently, the third electrode 74 is disposed between the first electrode 2 and the second electrode 3 in the plane direction of the piezoelectric material plate 71. It becomes the state arrange | positioned diagonally with respect to.
[0100]
In addition, the structure which mutually connects the electrode pattern which comprises the 1st electrode 2, the 2nd electrode 3, and the 3rd electrode 74, and the structure which draws out each electrode can be selected arbitrarily.
[0101]
In FIG. 11, an arrow drawn inside the piezoelectric material plate 71 indicates the polarization direction of the piezoelectric material plate 71. As shown in FIG. 11, the piezoelectric material plate 71 is polarized in a direction connecting the first electrode 2 and the second electrode 3, and the polarization direction is reversed with the third electrode 74 as a boundary.
[0102]
Next, an operation for ejecting droplets will be described.
[0103]
First, the liquid chamber 5 is filled with ink, and as shown in FIG. 11, a positive voltage is applied to the third electrode 74 while the first electrode 2 and the second electrode 3 are connected to the ground. At this time, the direction of the electric field generated between the first electrode 2 and the third electrode 74 and between the second electrode 3 and the third electrode 74 and the polarization direction of the piezoelectric material plate 71 are Since they match, the piezoelectric material plate 71 is deformed in the direct direction in the polarization direction. As shown in FIG. 11, as the piezoelectric material plate 71 is deformed, the area in which the second electrode 3 is formed moves upward in FIG. 11, thereby increasing the volume of the liquid chamber 5. Here, the deformation direction of the piezoelectric material plate 71 is opposite to each other across the substantial center of the liquid chamber 5 in which the second electrode 3 is formed.
[0104]
Next, when the potential of the third electrode 74 is returned to the ground (0 V) while the first electrode 2 and the second electrode 3 are connected to the ground, the shape of the piezoelectric material plate 71 returns to the initial planar shape, A predetermined amount of ink is ejected from the liquid chamber 5 through the nozzle 8.
[0105]
In the droplet ejecting apparatus 700 of the seventh embodiment, the polarization direction of the piezoelectric material plate 71, that is, the expansion / contraction direction of the piezoelectric material plate is slightly inclined with respect to the surface direction of the piezoelectric material plate 71. For this reason, the displacement width of the piezoelectric material plate 71 in the vertical direction in FIG. 11 is larger than the deformation amount of the piezoelectric material plate 71 in the polarization direction. Therefore, the amount of deformation in the polarization direction of the piezoelectric material plate 71 required for giving a constant volume change to the liquid chamber 5 can be reduced, and the required drive voltage can be reduced. As a result, in the droplet ejecting apparatus 700 of the seventh embodiment, it is possible to reduce the cost of the apparatus by reducing the driving voltage, and to improve the energy efficiency by reducing the energy required for ink ejection. be able to.
[0106]
Further, in the droplet ejecting apparatus 700 of the seventh embodiment, the third electrode 74 is inserted between the first electrode 2 and the second electrode 3, so that the apparatus 100 of the first embodiment and In comparison, the same electric field strength can be obtained with a lower driving voltage. Therefore, the drive voltage can be further reduced.
[0107]
In manufacturing the droplet ejecting apparatus 700 according to the seventh embodiment, the same steps as those in the first embodiment can be used, and thus the description thereof is omitted.
[0108]
-Eighth embodiment-
Hereinafter, with reference to FIG. 12 and FIG. 13, an eighth embodiment in which the liquid droplet ejecting apparatus of the invention is applied to an ink jet head will be described.
[0109]
12 and 13 are cross-sectional views showing the droplet ejecting apparatus according to the eighth embodiment. FIG. 12 is a view showing a state where a drive voltage is applied, and FIG. 13 is a view showing a state where no drive voltage is applied. .
[0110]
As shown in FIGS. 12 and 13, the droplet ejecting apparatus 800 according to the first embodiment is configured by stacking a plurality of (six in this example) green sheets (sheet-like piezoelectric material) 1 a. The material plate 81, the first electrode 82 provided inside the piezoelectric material plate 81, the second electrode 83 provided inside the piezoelectric material plate 81, and the first electrode provided inside the piezoelectric material plate 81 The third liquid electrode 84, the first liquid chamber plate 86 in which a plurality of through holes corresponding to the liquid chamber 85 are formed, and the second liquid in which a through hole having a smaller diameter than the first liquid chamber plate 6 is formed. A chamber plate 87 and a nozzle plate 89 in which a plurality of nozzles 88 corresponding to the liquid chambers 85 are formed are provided.
[0111]
As shown in FIGS. 12 and 13, the piezoelectric material plate 81, the first liquid chamber plate 86, the second liquid chamber plate 87, and the nozzle plate 89 are sequentially stacked, so that a plurality of liquid chambers 85 including the nozzles 88 are provided. Are formed in an array. The piezoelectric material plate 81 is supported by the first liquid chamber plate 86, and the support position is deformed with the support position as a fulcrum.
[0112]
The first electrode 82 is provided corresponding to each liquid chamber 85 and is located at a support position of the piezoelectric material plate 81 supported by the liquid chamber plate 86. The first electrode 82 is configured by electrically connecting three-layer electrode patterns formed in the middle of the green sheet 1a. As shown in FIGS. 12 and 13, the first electrode 82 is formed by overlapping the same electrode pattern in the thickness direction of the piezoelectric material plate 81.
[0113]
The second electrode 83 is provided corresponding to each liquid chamber 85 and is located at a substantially central portion of each liquid chamber 85. The second electrode 83 is configured by electrically connecting three-layer electrode patterns formed in the middle of the green sheet 1a. As shown in FIGS. 12 and 13, the second electrode 83 is formed by overlapping the same electrode pattern in the thickness direction of the piezoelectric material plate 81.
[0114]
In addition, the first electrode 82 is located generally below the piezoelectric material plate 81 in FIG. 11, while the second electrode 83 is located generally above the piezoelectric material plate 81 in FIG. is doing.
[0115]
The third electrode 84 is provided corresponding to each liquid chamber 85 and is disposed between the first electrode 82 and the second electrode 83. The third electrode 84 is configured by electrically connecting five layers of electrode patterns formed in the middle of the green sheet 1a. As shown in FIGS. 12 and 13, the third electrode 84 is formed by overlapping the same electrode pattern in the thickness direction of the piezoelectric material plate 81.
[0116]
In addition, the structure which connects the electrode pattern which comprises the 1st electrode 82, the 2nd electrode 83, and the 3rd electrode 84 mutually, and the structure which draws out each electrode can be selected arbitrarily.
[0117]
In FIG. 12, an arrow (corresponding to an arrow indicated by a symbol “A” in FIG. 1) drawn inside the piezoelectric material plate 81 indicates the polarization direction of the piezoelectric material plate 81. As shown in each drawing, the piezoelectric material plate 81 is polarized in a direction connecting the first electrode 82 and the third electrode 84 and between the second electrode 83 and the third electrode 84. Yes.
[0118]
Next, an operation for ejecting droplets will be described with reference to FIGS.
[0119]
First, ink is filled into the liquid chamber 85, and as shown in FIG. 12, a positive voltage is applied to the third electrode 84 while the first electrode 82 and the second electrode 83 are connected to the ground. At this time, the direction of the electric field generated between the first electrode 82 and the third electrode 84 and between the second electrode 83 and the third electrode 84 and the polarization direction of the piezoelectric material plate 81 are Since they coincide with each other, the piezoelectric material plate 81 is deformed so that any region extends in the direct mode in the polarization direction. As shown in FIG. 12, with the deformation of the piezoelectric material plate 81, the region in which the second electrode 83 is formed moves upward in FIG. 12, so that the volume of the liquid chamber 5 increases. Here, the deformation direction of the piezoelectric material plate 81 is opposite to each other across substantially the center of the liquid chamber 5 where the second electrode 83 is formed.
[0120]
Next, when the potential of the third electrode 84 is returned to the ground (0 V) while the first electrode 82 and the second electrode 83 are connected to the ground, the piezoelectric material plate 81 is planar as shown in FIG. Then, a predetermined amount of ink 10 is ejected from the liquid chamber 85 through the nozzle 88.
[0121]
As shown in FIGS. 12 and 13, in the droplet ejecting apparatus 800 of the eighth embodiment, the polarization direction of the piezoelectric material plate 81, that is, the expansion and contraction direction of the piezoelectric material plate 81 is substantially the whole piezoelectric material plate 81. It is slightly inclined with respect to the surface direction (the left-right direction in FIGS. 12 and 13). For this reason, the displacement width of the piezoelectric material plate 81 in the vertical direction in FIGS. 12 and 13 is larger than the deformation amount of the piezoelectric material plate 81 in the polarization direction. Therefore, it is possible to reduce the amount of deformation of the piezoelectric material plate 81 in the polarization direction necessary for giving a constant volume change to the liquid chamber 5, and to reduce the necessary driving voltage. As a result, according to the droplet ejecting apparatus 800 of the eighth embodiment, the cost of the apparatus can be reduced by reducing the driving voltage, and the energy efficiency is improved by reducing the energy required for ink ejection. be able to.
[0122]
Hereinafter, a manufacturing method of the droplet ejecting apparatus 800 according to the eighth embodiment will be described.
[0123]
The piezoelectric material plate 81 can be manufactured by laminating and baking a plurality of sheet-like piezoelectric materials, which are green sheets 1a. At this time, the material of the first electrode 2 and the second electrode 3 (conductive paste material) is printed in a green sheet shape with a predetermined pattern, so that the first sheet 1a is fired simultaneously with the first sheet. An electrode 82, a second electrode 83, and a third electrode 84 are formed.
[0124]
Next, the piezoelectric material plate 81 is polarized by applying a DC voltage between the first electrode 82 and the third electrode 84 and between the second electrode 83 and the third electrode 84. . Specifically, the first electrode 82 and the second electrode 83 are connected to a negative potential, the third electrode 83 is connected to a positive potential, and between the first electrode 82 and the third electrode 84, and By generating an electric field between the second electrode 83 and the third electrode 84, it is polarized in the direction of the arrows shown in FIGS.
[0125]
As shown in FIGS. 12 and 13, the first electrode 82 and the second electrode 83 are provided at positions shifted in the vertical direction in each figure as a whole, and the third electrode 84 is the first electrode. Since it is located between the second electrode 83 and the second electrode 83, the polarization direction is slightly inclined with respect to the surface direction of the piezoelectric material plate 81. Further, since the electrode used for polarization and the electrode used for driving the piezoelectric material plate 81 are common, the direction of the electric field coincides with the polarization direction when the piezoelectric material plate 81 is driven.
[0126]
Next, the piezoelectric material plate 81, the first liquid chamber plate 86, the second liquid chamber plate 87, and the nozzle plate 89 are sequentially stacked, whereby the droplet ejecting apparatus 800 of the eighth embodiment is manufactured.
[0127]
Note that the order of the step of polarizing the piezoelectric material plate 81 and the step of laminating the piezoelectric material plate 81, the first liquid chamber plate 86, the second liquid chamber plate 87, and the nozzle plate 89 may be interchanged.
[0128]
In the first to eighth embodiments, a part of the wall surface of the liquid chamber is constituted by the piezoelectric material plate itself, but the wall surface of the liquid chamber is constituted by another member, and the wall surface is formed by the piezoelectric material plate. You may drive using the deformation | transformation of.
[0129]
-Inkjet printer-
Hereinafter, with reference to FIG. 14, an ink jet printer equipped with the droplet ejecting apparatus of the present invention will be described. FIG. 14 is a perspective view showing a main part of the ink jet printer.
[0130]
A platen 110 shown in FIG. 14 functions as a sheet conveying means for conveying a sheet as a recording medium, is rotatably attached to a frame 113 by a shaft 112, and is driven by a motor 114. The motor 114 serves as a driving means for the platen 110, and the driving force is transmitted to the platen 110 through several gears as shown in FIG. A sheet 111 is set on the platen 110, and an ink jet print head is provided facing the platen 110. The droplet ejecting apparatus 100 or the like as an ink jet print head includes an ink tank filled with ink and serving as an ink supply tank, and an ink supply path for supplying ink from the ink tank to the droplet ejecting apparatus 100. It is placed on a carriage 118 together with an ink supply device 116 composed of a connecting portion that connects a droplet ejecting device and an ink tank. The carriage 118 is slidably supported by two guide rods 120 disposed in parallel to the axis of the platen 110, and a timing belt 124 wound around a pair of pulleys 122 is coupled to the pulley 122. Together with the motor 123 that transmits the driving force, it constitutes a carriage conveying means. Then, one pulley 122 is rotated by a motor 123, and the timing belt 124 is sent to be moved along the platen 110 to the carriage 118.
[0131]
The droplet ejecting apparatus of the present invention is not limited to application to an ink jet printer, and can be applied to various printing apparatuses and various coating apparatuses.
[0132]
Further, the ink jet print head placed on the carriage may be formed integrally with the droplet ejecting device 100, the ink tank, and the connecting portion including the ink supply path, or may be detachable from each other. . Further, only the droplet ejecting device 100 may be placed on the carriage, or the droplet ejecting device 100 and the connecting portion may be placed.
[0133]
In short, the droplet ejecting apparatus according to each claim of the present invention includes a carriage on which a print head is mounted, a paper transport unit that transports paper, and transports the carriage in a direction that intersects the paper transport direction of the paper transport unit. It can be employed as a print head of an ink jet printer comprising a carriage conveying means.
[0134]
In addition, it is necessary to provide an ink tank for storing ink in order to supply ink to the print head. This ink tank is mounted on the carriage in a detachable and replaceable manner. This replacement mode is a mode in which only the ink tank is replaced when the print head is fixed to the carriage so as not to be replaced. In the case of this replacement mode, since the droplet ejecting apparatus is continuously used even after the ink tank is replaced, the durability of the droplet ejecting apparatus must be high. On the other hand, the droplet ejecting device and the ink tank are integrated as an ink unit, and a drive signal transmitted connector portion that exposes each nozzle driving signal line is provided in the ink unit, and the head of the printer control device is provided on the carriage. A drive signal transmission connector portion that exposes a signal line for outputting a drive signal is provided, and when the ink unit is mounted on the carriage, each signal line of the drive signal transmitted connector portion is a signal of the drive signal transmission connector portion of the carriage. It is also possible to adopt a form in which each nozzle is driven by a head drive signal from a printer control device connected to a line. When this ink unit is used, the ink unit is replaced when the ink is completely consumed. For this reason, the droplet ejecting device only needs to operate reliably with respect to the amount of ink in the ink tank of the ink unit. Therefore, the durability of the droplet ejecting device is small compared to the case where the ink tank is replaced. Cost can be small. Further, when embodied as an ink unit, the structure of the ink supply path between the ink tank and the droplet ejecting device can be simplified, so the structure of the ink unit can be simplified and inexpensive.
[0135]
When the ink tank is made replaceable, the ink supply path between the droplet ejecting device and the ink tank will be exposed to outside air at the time of replacement. If the ink unit is embodied in the above-described integrated structure, such a problem does not occur.
[0136]
In addition to the type that drives the platen, as the sheet conveying means, a flat platen is fixed on the conveying path, and a pair of conveying rollers are provided upstream and downstream of the platen, and these two pairs of conveying rollers are used. It may be of a type that conveys paper. The print head described above is a type of print head conveyed by a carriage, but may be of a type that can simultaneously print the entire width of the paper.
[0137]
【The invention's effect】
As described above, according to the droplet ejecting apparatus of the present invention, since the expansion / contraction direction of the piezoelectric material plate is inclined with respect to the surface direction of the piezoelectric material plate, the piezoelectric material plate is compared with the deformation amount of the piezoelectric material plate. Since the displacement width of the wall surface driven by the material plate can be increased, the driving voltage can be lowered, and a droplet ejecting apparatus with good energy efficiency can be obtained. Further, according to the liquid droplet ejecting apparatus of the present invention, since the polarization direction of the piezoelectric material plate is inclined with respect to the surface direction of the piezoelectric material plate, the piezoelectric material plate is driven by the amount of deformation of the piezoelectric material plate. Since the displacement width of the wall surface can be increased, the driving voltage can be reduced, and a droplet ejecting apparatus with good energy efficiency can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a liquid droplet ejecting apparatus according to a first embodiment.
FIG. 2 is a cross-sectional view illustrating a state in which ink is filled in a liquid chamber of the liquid droplet ejecting apparatus according to the first embodiment.
3 is a cross-sectional view taken along line III-III in FIG.
FIG. 4 is a cross-sectional view showing a state where a driving voltage is applied.
FIG. 5 is a cross-sectional view showing a state where application of a drive voltage is stopped.
FIG. 6 is a cross-sectional view illustrating a droplet ejecting apparatus according to a second embodiment.
FIG. 7 is a cross-sectional view illustrating a liquid droplet ejecting apparatus according to a third embodiment.
FIG. 8 is a cross-sectional view showing a droplet ejecting apparatus according to a fourth embodiment.
FIG. 9 is a cross-sectional view illustrating a droplet ejecting apparatus according to a fifth embodiment.
FIG. 10 is a sectional view showing a droplet ejecting apparatus according to a sixth embodiment.
FIG. 11 is a sectional view showing a droplet ejecting apparatus according to a seventh embodiment.
FIG. 12 is a cross-sectional view showing a liquid droplet ejecting apparatus according to an eighth embodiment.
FIG. 13 is a sectional view showing a droplet ejecting apparatus according to an eighth embodiment.
FIG. 14 is a perspective view showing a main part of the ink jet printer.
[Explanation of symbols]
1 Piezoelectric material plate
1a Sheet-shaped piezoelectric material
2 First electrode (electrode)
3 Second electrode (electrode)
5 Liquid chamber

Claims (7)

In a liquid droplet ejecting apparatus that includes a piezoelectric material plate for deforming at least a part of the wall surface of the liquid chamber, and ejects liquid droplets from the liquid chamber by deformation of the piezoelectric material plate in a direct mode.
The polarization direction of the piezoelectric material plate is inclined with respect to the surface direction of the piezoelectric material plate, and the droplets are ejected by deformation of the piezoelectric material plate in the polarization direction by applying a voltage to the piezoelectric material plate. Is configured as
2. A droplet ejecting apparatus according to claim 1, wherein a polarization direction of the piezoelectric material plate is substantially the same as an electric field applied to the piezoelectric material plate . The piezoelectric material plate is provided with a first electrode having a constant potential and a second electrode to which a voltage for deforming the piezoelectric material plate is applied,
2. The droplet ejecting apparatus according to claim 1 , wherein the first electrode and the second electrode are shifted from each other when viewed from a direction orthogonal to the surface direction . 2. The piezoelectric material plate has a pair of regions sandwiching substantially the center of the liquid chamber, and the deformation of each region when the voltage is applied is in directions opposite to each other. Or the droplet ejecting apparatus according to 2. 4. The droplet ejecting apparatus according to claim 1, wherein the polarization direction is inclined within an angle range of 10 to 70 degrees with respect to a surface direction of the piezoelectric material plate. The electrodes for applying an electric field to piezoelectric material plate, the droplet ejecting apparatus according to any one of claims 1 to 4, characterized in that provided inside the piezoelectric material plate. The droplet ejecting apparatus according to claim 1, wherein the electrode is formed on a surface of the piezoelectric material plate. 7. The droplet ejecting apparatus according to claim 5, wherein the piezoelectric material plate is configured by laminating a plurality of sheet-like piezoelectric materials.

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