JP2002292865A - Liquid drop ejector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid drop ejector having a high energy efficiency in which a sufficient deformation can be imparted to a piezoelectric material plate even if the driving voltage is low. SOLUTION: The liquid drop ejector comprises a piezoelectric material plate 1 for deforming at least a part of the wall face of liquid chambers 5 and ejects liquid drops from the liquid chambers 5 utilizing deformation of the piezoelectric material plate 1 under direct mode wherein the elongating/contracting direction of the piezoelectric material plate 1 is inclined against the plane direction thereof and liquid drops are ejected by applying a voltage to the piezoelectric material plate 1 and deforming it in the elongating/contracting direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid droplet ejecting apparatus having a piezoelectric material plate for deforming at least a part of a wall of a liquid chamber.

[0002]

2. Description of the Related Art As an ink jet head used in an ink jet type printer, one using a piezoelectric element is known. In such an inkjet head, a plate-shaped member (piezoelectric material plate) made of a piezoelectric material is used for a wall covering the ink pressure chamber. By applying a drive voltage to the piezoelectric material plate, the wall is deformed, and pressure is induced in the ink in the ink pressure chamber. Thus, ink is ejected from nozzles that are continuous with the ink pressure chamber.

[0003] As modes for driving and deforming the piezoelectric material plate, there are usually a direct mode and a shear mode. In the direct mode, the direction of the electric field due to the application of the driving voltage matches the deformation direction of the piezoelectric material plate. In the share mode, the direction of the electric field differs from the deformation direction of the piezoelectric material plate.

[0004] Among these modes, in the direct mode, the direction of the electric field when a driving voltage is applied and the direction of polarization of the piezoelectric material plate coincide with each other. For this reason, problems such as performance degradation of the ink-jet head due to weakening of polarization due to repeated application of the drive voltage do not occur. There is also an advantage in manufacturing that the electrode itself to which a drive voltage is applied can be used when polarizing the piezoelectric material plate.

[0005]

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 the energy is high. There is a problem of inefficiency.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a droplet ejecting apparatus which can impart a sufficient amount of deformation to a piezoelectric material plate even when a driving voltage is low, and has good energy efficiency.

[0007]

The droplet ejecting apparatus of the present invention includes a piezoelectric material plate (1) for deforming at least a part of a wall surface of a liquid chamber (5). In a droplet ejecting apparatus that ejects droplets from a liquid chamber (5) using deformation in a direct mode, the direction of expansion and contraction of a piezoelectric material plate (1) is inclined with respect to the surface direction of the piezoelectric material plate (1). The method is characterized in that the piezoelectric material plate (1) is deformed in the direction of expansion and contraction by applying a voltage to the piezoelectric material plate (1) to eject droplets.

According to this liquid droplet ejecting apparatus, since the direction of expansion and contraction of the piezoelectric material plate is inclined with respect to the surface direction of the piezoelectric material plate, the volume of the liquid chamber can be easily changed with little energy loss. Since the displacement width of the wall surface driven by the piezoelectric material plate can be increased even with the amount of deformation of the piezoelectric material plate, the drive voltage can be reduced, and a droplet ejecting apparatus with good energy efficiency can be obtained.

The direction of expansion and contraction may be inclined at an angle of 10 to 70 degrees with respect to the plane direction of the piezoelectric material plate (1).

In this case, the displacement width of the wall surface driven by the piezoelectric material plate can be sufficiently increased as compared with the amount of deformation of the piezoelectric material plate.

The liquid 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. In the liquid droplet ejecting apparatus for ejecting liquid droplets from the liquid chamber (5), the polarization direction of the piezoelectric material plate (1) is inclined with respect to the surface direction of the piezoelectric material plate (1), and the voltage applied to the piezoelectric material plate is changed. Droplets are ejected by the deformation of the piezoelectric material plate (1) in the polarization direction due to the application of the liquid crystal.

According to this droplet ejecting apparatus, 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 piezoelectric material plate in comparison with the deformation amount of the piezoelectric material plate. Can increase the displacement width of the wall
Even if the same driving voltage is applied, a droplet ejecting apparatus having good energy efficiency can be obtained.

The polarization direction may be inclined at an angle of 10 to 70 degrees with respect to the plane direction of the piezoelectric material plate (1).

In this case, the displacement width of the wall surface driven by the piezoelectric material plate can be sufficiently increased as compared with the amount of deformation of the piezoelectric material plate.

The piezoelectric material plate (1) has a pair of regions sandwiching substantially the center of the liquid chamber (5), and when each of the regions is deformed when a voltage is applied, even if the directions are opposite to each other. Good.

In this case, the displacement of the piezoelectric material plate can be increased even with the same driving voltage.

The direction of polarization of the piezoelectric material plate (1) may be substantially the same as the direction of the electric field applied to the piezoelectric material plate (1).

In this case, a common electrode can be used as the electrode used for polarization and the electrode used for driving. Further, the applied electric field works effectively for displacement of the piezoelectric material plate in the direct mode.

Electrodes (2, 3) for applying an electric field to the piezoelectric material plate may be provided inside the piezoelectric material plate (1).

In this case, it is possible to prevent the electrode from being deteriorated due to the electrode coming into contact with the liquid in the liquid chamber.

The piezoelectric material plate (1) may be constituted by laminating a plurality of sheet-like piezoelectric materials (1a).

In this case, the electrodes can be easily formed inside the piezoelectric material plate.

The electrodes (2, 3) may be formed on the surface of the piezoelectric material plate (1).

In this case, the electrodes (2, 3) can be easily formed by using a printing method or the like.

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 PREFERRED EMBODIMENTS First Embodiment A first embodiment in which a liquid droplet ejecting apparatus according to the present invention is applied to an ink jet head will be described below with reference to FIGS.

FIG. 1 is a cross-sectional view showing a liquid droplet ejecting apparatus according to the first embodiment, and FIG. 2 is a cross-sectional view showing a state where ink is filled in a liquid chamber of the liquid droplet ejecting apparatus according to the first embodiment. 3 of FIG. 2
FIG. 4 is a cross-sectional view taken along the line III-III, FIG. 4 is a cross-sectional view showing a state where the driving voltage is applied, and FIG. 5 is a cross-sectional view showing a state where the application of the driving voltage is stopped.

As shown in FIGS. 1 to 3, the droplet jetting device 100 according to the first embodiment is configured by laminating a plurality of (six in this example) green sheets (sheet-like piezoelectric materials) 1a. Piezoelectric material plate 1, a first electrode 2 provided inside the piezoelectric material plate 1, a second electrode 3 provided inside the piezoelectric material plate 1, and a plurality of The liquid chamber 5 is formed by closing the openings of the plurality of through holes corresponding to the liquid chambers 5 of the first liquid chamber plate 6 together with the first liquid chamber plate 6 having the through holes and the piezoelectric material plate 1. The second liquid chamber plate 7 has a through hole as an ink supply path 5b to the liquid chamber 5 and a through hole as an ink discharge path formed at a predetermined position of the liquid chamber 4. Plate 9 in which a plurality of nozzles 8 corresponding to each liquid chamber 5 are formed
And

As shown in FIGS. 1 to 3, the piezoelectric material plate 1,
By sequentially laminating the first liquid chamber plate 6, the second liquid chamber plate 7, and the nozzle plate 9, a plurality of liquid chambers 5 having the nozzles 8 are arranged and formed. The piezoelectric material plate 1 forms a part of the wall of the liquid chamber 5 by closing the through hole of the first liquid chamber plate 6. The piezoelectric material plate 1 is supported by the first liquid chamber plate 6, and is deformed with its supporting position as a fulcrum.

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 supplied to the nozzle 8 of the nozzle plate 9 through a through hole as the ink discharge passage 5a of the second liquid chamber plate 7, and the ink is discharged from the nozzle 8. . On the other hand, an amount of ink corresponding to the amount of the ejected ink is supplied to the liquid chamber 5 through the through-hole as the ink supply path 5b of the second liquid chamber plate 7.

The first electrodes 2 are provided corresponding to the respective liquid chambers 5 and are located at the positions where the piezoelectric material plates 1 supported by the liquid chamber plates 6 are supported. The first electrode 2 is a green sheet 1a
Are formed by electrically connecting three layers of electrode patterns formed in the middle of the above. As shown in FIG. 1 and the like, the electrode pattern of the first electrode 2 is shown in FIG.
Are formed so that the area thereof is gradually reduced from below to above.

The second electrodes 3 are provided corresponding to the respective liquid chambers 5 and are located at substantially the center of the respective liquid chambers 5. Second electrode 3
Is formed by electrically connecting three layers of 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 is gradually increased from the bottom to the top in FIG. Further, the first electrode 2 is generally located at a lower position in FIG. 1, while the second electrode 3 is generally located at an upper position in FIG.

The configuration in which the electrode patterns constituting the first electrode 2 and the second electrode 3 are connected to each other and the configuration in which each electrode is drawn out can be arbitrarily selected.

Arrows drawn inside the piezoelectric material plate 1 in FIGS. 1 to 3 (arrows indicated by the symbol "A" in FIG. 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.

Next, referring to FIGS. 2, 4 and 5,
The operation of ejecting a droplet will be described.

As shown in FIG. 2, first, the inside of the liquid chamber 5 is filled with ink. At this time, the first electrode 2 and the second electrode 2
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 matches the polarization direction of the piezoelectric material plate 1, the piezoelectric material plate 1 is polarized in a direct mode in the polarization direction. Deform to stretch in the direction. As shown in FIG. 4, as the piezoelectric material plate 1 is deformed, the area where the second electrode 3 is formed moves upward in FIG. 4, so that the volume of the liquid chamber 5 increases and the increased volume increases. Is supplied from an ink tank which is an ink supply tank (not shown). Here, the deformation directions of the piezoelectric material plate 1 are opposite to each other across the substantially center of the liquid chamber 5 in which the second electrode 3 is formed.

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. As shown in FIG. 5, a predetermined amount of ink 10 is ejected from the liquid chamber 5 through the nozzle 8.

As shown in FIGS. 1 to 5, in the liquid droplet ejecting apparatus 100 according to the first embodiment, the polarization direction of the piezoelectric material plate 1,
That is, the direction of expansion and contraction of the piezoelectric material plate is slightly inclined with respect to the surface direction of the piezoelectric material plate 1 (the left-right direction in FIGS. 1 to 5). Therefore, the displacement of the piezoelectric material plate 1 in the polarization direction is easily transmitted as a change in the volume of the liquid chamber 5, and the piezoelectric material plate 1
Of the piezoelectric material plate 1 with respect to the amount of deformation of
The vertical displacement width in FIG. 5, that is, the change in the volume of the liquid chamber 5 becomes large. Therefore, it is possible to reduce the amount of deformation of the piezoelectric material plate 1 in the polarization direction required to give a constant volume change to the liquid chamber 5, and to reduce the required drive voltage. As a result, in the droplet ejecting apparatus 100 of the first embodiment, the drive voltage is reduced, so that the cost of the apparatus can be reduced, and the energy required for ejecting ink is reduced to improve the energy efficiency. be able to.

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 plane direction of the piezoelectric material plate 1 in the range of 10 to 70 degrees.

Hereinafter, a method of manufacturing the droplet ejecting apparatus 100 according to the first embodiment will be described with reference to FIGS.

The piezoelectric material plate 1 can be manufactured by laminating and firing a plurality of sheet-shaped green sheets, which are 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 fired simultaneously with the firing of the green sheet. And the second
Is formed.

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 set to a negative potential,
Of the first electrode 2 and the second electrode 3
By generating an electric field between the electrodes 3, the electrodes 3 are polarized in the directions of the arrows shown in FIGS.

As shown in FIGS. 1 and 3, since the first electrode 2 and the second electrode 3 are provided at positions shifted in the vertical direction in each figure as a whole, the polarization direction is the piezoelectric material plate. 1 is slightly inclined with respect to the plane direction. In addition, since the electrode used for polarization and the electrode used for driving the piezoelectric material plate 1 are common, when the piezoelectric material plate 1 is driven, the direction of the electric field matches the polarization direction.

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 laminated to manufacture the droplet ejecting apparatus 100 of the first embodiment. Is done.

The step of polarizing the piezoelectric material plate 1 includes:
The order of 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.

Second Embodiment Hereinafter, a second embodiment in which the 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 in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the liquid droplet ejecting apparatus 200 according to the second embodiment, the first electrodes 22 are provided corresponding to the respective liquid chambers 5 and are located at the supporting positions of the piezoelectric material plates 21 supported by the liquid chamber plates 6. I do. The first electrode 22 is configured by electrically connecting three electrode patterns formed in the middle of the green sheet 1a. The electrode pattern of the first electrode 22 is formed so that the area thereof is gradually increased from the bottom in FIG. 6 to the top in the thickness direction of the piezoelectric material plate 21.

In the droplet ejecting apparatus 200 of the second embodiment, the second electrodes 23 are provided corresponding to the respective liquid chambers 5 and are located at substantially the center of each liquid chamber 5. The second electrode 23 is configured by electrically connecting three layers of electrode patterns formed in the middle of the green sheet 1a. The electrode pattern of the second electrode 23 corresponds to the thickness direction of the piezoelectric material plate 21 in FIG.
Are formed so that the area thereof is gradually reduced from below to above. In addition, the first electrode 22 is generally located closer to the upper side of the piezoelectric material plate 21 in FIG. 6, while the second electrode 23 is generally located closer to the lower side of the piezoelectric material plate 21 in FIG. are doing.

The first electrode 22 and the second electrode 2
The configuration in which the electrode patterns constituting the electrode pattern 3 are connected to each other and the configuration in which each electrode is drawn out can be arbitrarily selected.

In FIG. 6, the 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.

Next, the operation of ejecting droplets will be described.

First, the inside of 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 matches the polarization direction of the piezoelectric material plate 21, the piezoelectric material plate 21 extends in the polarization direction in the direct mode. To be deformed. 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 is reduced. Therefore, as shown in FIG. 6, a predetermined amount of ink 10 is ejected from the liquid chamber 5 via the nozzle 8. Here, the directions of deformation of the piezoelectric material plates 21 are opposite to each other across the substantially center of the liquid chamber 5 in which the second electrode 23 is formed.

By stopping the application of the voltage to the second electrode 23, the piezoelectric material plate 21 returns to the original state, and the volume of the liquid chamber 5 due to the piezoelectric material plate 21 at this time is changed. The supplied ink is supplied from the ink supply device 116.

In the liquid droplet ejecting apparatus 200 of the second embodiment, the polarization direction of the piezoelectric material plate 21, that is, the direction of expansion and contraction 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 amount of deformation 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 required to give a constant volume change to the liquid chamber 5, and to reduce the required driving voltage. As a result, in the droplet ejecting apparatus 200 according to the second embodiment, the driving voltage decreases,
The cost of the apparatus can be reduced, and the energy required for discharging the ink can be reduced to improve the energy efficiency.

The droplet ejecting apparatus 20 of the second embodiment
In manufacturing 0, the same steps as those in the first embodiment can be used, and the description thereof is omitted.

Third Embodiment Hereinafter, a third embodiment in which the droplet ejecting apparatus of the present invention is applied to an ink jet head will be described with reference to FIG. In FIG. 7, the same elements as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the liquid droplet ejecting apparatus 300 according to the third embodiment, the first electrodes 32 are provided corresponding to the respective liquid chambers 5 and are located at the supporting positions of the piezoelectric material plate 31 supported by the liquid chamber plate 6. I do. The first electrode 32 is formed by electrically connecting two electrode patterns of the same pattern formed in the middle of the green sheet 1a.

The second electrodes 33 are provided corresponding to the respective liquid chambers 5, and are located at substantially the center portions of the respective liquid chambers 5. The second electrode 33 is configured by electrically connecting two electrode patterns of the same pattern formed in the middle of the green sheet 1a.

While the first electrode 32 as a whole is located below the piezoelectric material plate 31 in FIG.
The second electrode 33 as a whole is the piezoelectric material plate 3 in FIG.
1 is located above. However, there is no change in the area of each electrode in the thickness direction of the piezoelectric material plate 31 as in the first embodiment.

The first electrode 32 and the second electrode 3
The configuration in which the electrode patterns constituting the electrode pattern 3 are connected to each other and the configuration in which each electrode is drawn out can be arbitrarily selected.

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.

Next, the operation of ejecting a droplet will be described.

First, the liquid chamber 5 is filled with ink, and a positive voltage is applied to the second electrode 33 while the first electrode 32 is connected to the ground, as shown in FIG. At this time, since the direction of the electric field generated between the first electrode 32 and the second electrode 33 matches the polarization direction of the piezoelectric material plate 31, the piezoelectric material plate 31 is polarized in the polarization direction in the direct mode. Deform to stretch in the direction. As shown in FIG. 7, with the deformation of the piezoelectric material plate 31, the second electrode 33
By moving the region in which is formed upward in FIG. 4, the volume of the liquid chamber 5 increases, and ink corresponding to the increase in the volume of the liquid chamber 5 is supplied from the ink supply device 116. Here, the deformation direction of the piezoelectric material plate 31 is the second direction.
The directions are opposite to each other across the substantially center of the liquid chamber 5 in which the electrodes 33 are formed.

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, and the nozzle 8 A predetermined amount of ink is ejected from the liquid chamber 5 via.

In the liquid droplet ejecting apparatus 300 according to the third embodiment, the polarization direction of the piezoelectric material plate 31, that is, the direction of expansion and contraction of the piezoelectric material plate is slightly inclined with respect to the surface direction of the piezoelectric material plate 31. Therefore, 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, it is possible to reduce the amount of deformation of the piezoelectric material plate 31 in the polarization direction necessary for giving a constant volume change to the liquid chamber 5, and it is possible to reduce the required driving voltage. As a result, in the droplet ejection device 300 of the third embodiment, the driving voltage is reduced,
The cost of the apparatus can be reduced, and the energy required for discharging the ink can be reduced to improve the energy efficiency.

The droplet ejecting apparatus 30 of the third embodiment
In manufacturing 0, the same steps as those in the first embodiment can be used, and the description thereof is omitted.

Fourth Embodiment A fourth embodiment in which the droplet ejecting apparatus of the present invention is applied to an ink jet head will be described below with reference to FIG. In FIG. 8, the same elements as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the liquid droplet ejecting apparatus 400 according to the fourth embodiment, the first electrodes 42 are provided corresponding to the respective liquid chambers 5 and are located at the supporting positions of the piezoelectric material plate 41 supported by the liquid chamber plate 6. I do. The first electrode 42 is configured by electrically connecting two layers of electrode patterns formed in the middle of the green sheet 1a. The electrode pattern of the first electrode 42 is formed so that the area thereof is gradually increased from the lower side to the upper side in FIG. 8 with respect to the thickness direction of the piezoelectric material plate 41.

In the liquid droplet ejecting apparatus 400 of the fourth embodiment, the second electrodes 43 are provided corresponding to the respective liquid chambers 5 and are located at substantially the center of each liquid chamber 5. The second electrode 43 is configured by electrically connecting three electrode patterns formed in the middle of the green sheet 1a. The electrode pattern of the second electrode 43 corresponds to the thickness direction of the piezoelectric material plate 41 in FIG.
Are formed so that the area thereof is gradually reduced from below to above. Further, while the first electrode 42 is generally located above the piezoelectric material plate 41 in FIG. 8, the second electrode 43 is generally located below the piezoelectric material plate 41 in FIG. are doing.

The first electrode 42 and the second electrode 4
The configuration in which the electrode patterns constituting the electrode pattern 3 are connected to each other and the configuration in which each electrode is drawn out can be arbitrarily selected.

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.

As shown in FIG. 8, in the droplet ejecting apparatus 400 according to the fourth embodiment, a notch 41 a is formed in a part of the piezoelectric material plate 41 in a region where the second electrode 43 is formed. I have. By forming such a notch 41a, the piezoelectric material plate 41 is easily bent, and the amount of change in volume of the liquid chamber 5 when a drive voltage is applied can be increased.

Next, the operation of ejecting a droplet will be described.

First, the interior of the liquid chamber 5 is filled with ink, and a positive voltage is applied to the second electrode 43 while the first electrode 42 is connected to the ground, as shown in FIG. At this time, since the direction of the electric field generated between the first electrode 42 and the second electrode 43 matches the polarization direction of the piezoelectric material plate 41, the piezoelectric material plate 41 is deformed in the polarization direction in the direct mode. I do. As shown in FIG. 8, due to the deformation of the piezoelectric material plate 41, the region where the second electrode 43 is formed
By moving downward, the volume of the liquid chamber 5 decreases. 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 directions of deformation of the piezoelectric material plates 41 are opposite to each other across the substantially center of the liquid chamber 5 in which the second electrode 43 is formed.

In the liquid droplet ejecting apparatus 400 of the fourth embodiment, the polarization direction of the piezoelectric material plate 41, that is, the piezoelectric material plate 4
The direction of expansion and contraction of 1 is slightly inclined with respect to the surface direction of the piezoelectric material plate 41, and a portion that does not contribute to the deformation of the piezoelectric material plate 41 is cut out. Therefore, the displacement width of the piezoelectric material plate 41 in the vertical direction in FIG. 8 is larger than the amount of deformation of the piezoelectric material plate 41 in the polarization direction. Therefore, it is possible to reduce the amount of deformation of the piezoelectric material plate 41 in the polarization direction necessary for giving a constant volume change to the liquid chamber 5,
The required drive voltage can be further reduced. As a result, in the liquid droplet ejecting apparatus 400 of the fourth embodiment, the drive voltage is reduced, so that the cost of the apparatus can be reduced, and the energy required for discharging ink is reduced to improve the energy efficiency. be able to.

The droplet ejecting apparatus 40 of the fourth embodiment
In manufacturing 0, the same steps as in the first embodiment can be used. In order to form the notch 41a,
An opening may be 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 notches 41a may be formed by laminating the green sheets in a state where there is no opening, and thereafter performing mechanical processing or laser processing.

Fifth Embodiment Hereinafter, a fifth embodiment in which the droplet ejecting apparatus of the present invention is applied to an ink jet head will be described with reference to FIG. In FIG. 9, the same elements as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 9, in the liquid droplet ejecting apparatus 500 of the fifth embodiment, the first electrode 52 and the second electrode 53 correspond to the respective liquid chambers 5 and the piezoelectric material plates 51 respectively.
Is provided on the surface. The piezoelectric material plate 51 is formed by integrally sintering a piezoelectric material.

The first electrode 52 is connected to 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 substantially at the center of each liquid chamber 5.

The first electrode 52 and the second electrode 5
3 can be arbitrarily selected.

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.

Next, the operation of ejecting a droplet will be described.

First, the liquid chamber 5 is filled with ink, and a positive voltage is applied to the second electrode 53 while the first electrode 52 is connected to the ground, as shown in FIG. At this time, since the direction of the electric field generated between the first electrode 52 and the second electrode 53 matches 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 where the second electrode 53 is formed moves upward in FIG. 9, so that the volume of the liquid chamber 5 increases and the ink supply device From 116, ink corresponding to the volume increase of the liquid chamber 5 is supplied. Here, the directions of deformation of the piezoelectric material plates 51 are opposite to each other across the substantially center of the liquid chamber 5 in which the second electrode 53 is formed.

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, and the nozzle 8 A predetermined amount of ink is ejected from the liquid chamber 5 via.

In the liquid droplet ejecting apparatus 500 of the fifth embodiment, the polarization direction of the piezoelectric material plate 51, that is, the expansion and contraction direction of the piezoelectric material plate is slightly inclined with respect to the surface direction of the piezoelectric material plate 51. Therefore, the displacement width of the piezoelectric material plate 51 in the vertical direction in FIG. 9 is larger than the amount of deformation 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 it is possible to reduce the required driving voltage. As a result, in the droplet ejection device 500 of the fifth embodiment, the drive voltage is reduced,
The cost of the apparatus can be reduced, and the energy required for discharging the ink can be reduced to improve the energy efficiency.

The droplet jetting device 50 of the fifth embodiment
The first electrode 52 and the second electrode 53 at 0 are formed by patterning the material of the first electrode 52 and the second electrode 53 on the surface of the piezoelectric material plate 51 into a predetermined shape by printing or vapor deposition. Can be formed. Among these, the first electrode 52 is not formed on the surface of the piezoelectric material plate 51,
It may be formed on the first liquid chamber plate.

Sixth Embodiment Hereinafter, a sixth embodiment in which the droplet ejecting apparatus of the present invention is applied to an ink jet head will be described with reference to FIG. In FIG. 10, the same elements as those in the fifth embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 10, in the liquid droplet ejecting apparatus 600 according to the sixth embodiment, the piezoelectric material plate 61 is formed by integrally sintering a piezoelectric material.

As shown in FIG. 10, in the liquid 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 is connected to a lead-out portion 62 a formed on the surface of the piezoelectric material plate 61 and to the lead-out portion 62 a.
And an accommodating portion 62b accommodated in the inside. The second electrode 63 is a lead-out portion 63 formed on the surface of the piezoelectric material plate 61.
a, and an accommodating portion 63b connected to the drawer portion 63a and accommodated inside the piezoelectric material plate 61.

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 connected to the first liquid chamber plate via the lead portion 62a. 6 supported. On the other hand, the second electrode 63 is located substantially at the center of each liquid chamber 5.

The first electrode 62 and the second electrode 6
3 can be arbitrarily selected.

In FIG. 10, the arrow drawn inside the piezoelectric material plate 61 indicates the polarization direction of the piezoelectric material plate 61. Figure 1
As shown in FIG. 0, the piezoelectric material plate 61 is polarized in a direction connecting the first electrode 62 and the second electrode 63.

Next, the operation of ejecting a droplet will be described.

First, the inside of the liquid chamber 5 is filled with ink, and a positive voltage is applied to the second electrode 63 while the first electrode 62 is connected to the ground as shown in FIG. At this time, since the direction of the electric field generated between the first electrode 62 and the second electrode 63 matches the polarization direction of the piezoelectric material plate 61, the piezoelectric material plate 61 is in a direct mode in the polarization direction. Deform to stretch. As shown in FIG. 10, as the piezoelectric material plate 61 is deformed, the area where the second electrode 63 is formed moves upward in FIG. 10, thereby increasing the volume of the liquid chamber 5 and supplying ink. Is done. Here, the deformation directions of the piezoelectric material plate 61 are opposite to each other across the substantially center of the liquid chamber 5 in which the second electrode 63 is formed.

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, and the nozzle 8 A predetermined amount of ink is ejected from the liquid chamber 5 via.

In the liquid droplet ejecting apparatus 600 according to the sixth embodiment, the polarization direction of the piezoelectric material plate 61, that is, the expansion and contraction direction of the piezoelectric material plate is slightly inclined with respect to the surface direction of the piezoelectric material plate 61. Therefore, the displacement width of the piezoelectric material plate 61 in the vertical direction in FIG. 10 is larger than the amount of deformation of the piezoelectric material plate 61 in the polarization direction. Therefore, it is possible to reduce the amount of deformation of the piezoelectric material plate 61 in the polarization direction required for giving a constant volume change to the liquid chamber 5, and to reduce the required driving voltage. As a result, in the droplet ejecting apparatus 600 of the sixth embodiment, the drive voltage can be reduced, and the cost of the apparatus can be reduced.
Energy required for ink ejection can be reduced to improve energy efficiency.

The droplet ejection device 60 according to the sixth embodiment
The housing portion 62b of the first electrode 62 and the housing portion 63b of the second electrode 63 at 0 can be formed, for example, by forming a cutout in the piezoelectric material plate 61 and filling the cutout with an electrode material. In addition, the extraction portion 62 of the first electrode 62
The lead portion a 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 by printing or vapor deposition.

Seventh Embodiment A seventh embodiment in which the droplet ejecting apparatus of the present invention is applied to an ink jet head will be described below with reference to FIG. In FIG. 11, the same elements as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

In the droplet ejecting apparatus 700 of the seventh embodiment, the same first droplet ejecting apparatus 100 as the droplet ejecting apparatus 100 of the first embodiment is used.
In addition to the second electrode 3 and the second electrode 3, a third electrode 74 is provided corresponding to each liquid chamber 5. As shown in FIG. 11, the third electrode 74 is configured by electrically connecting five 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 the first electrode pattern.
Between the second electrode 3 and the second electrode 3 is disposed obliquely with respect to the surface direction of the piezoelectric material plate 71.

The configuration in which the electrode patterns constituting the first electrode 2, the second electrode 3, and the third electrode 74 are connected to each other and the configuration in which each electrode is drawn out can be arbitrarily selected.

In FIG. 11, an arrow drawn inside the piezoelectric material plate 71 indicates the polarization direction of the piezoelectric material plate 71. Figure 1
As shown in FIG. 1, the piezoelectric material plate 71 is connected to the first electrode 2 and the second electrode 2.
Is polarized in a direction connecting the electrode 3 with the third direction.
Are inverted with the electrode 74 as a boundary.

Next, the operation of ejecting a droplet will be described.

First, ink is filled in the liquid chamber 5, 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. Apply. At this time, the direction of the electric field generated between the first electrode 2 and the third electrode 74, between the second electrode 3 and the third electrode 74, and the polarization direction of the piezoelectric material plate 71 Since they match, the piezoelectric material plate 71 is deformed in the polarization mode in the direct mode. As shown in FIG. 11, as the piezoelectric material plate 71 is deformed, the area where the second electrode 3 is formed moves upward in FIG. 11, so that the volume of the liquid chamber 5 increases. Here, the directions of deformation of the piezoelectric material plates 71 are opposite to each other across the substantially center of the liquid chamber 5 in which the second electrode 3 is formed.

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 is changed to the initial planar shape. Then, a predetermined amount of ink is ejected from the liquid chamber 5 through the nozzle 8.

In the droplet jetting device 700 of the seventh embodiment, the polarization direction of the piezoelectric material plate 71, that is, the direction of expansion and contraction of the piezoelectric material plate is slightly inclined with respect to the surface direction of the piezoelectric material plate 71. Therefore, the displacement width of the piezoelectric material plate 71 in the vertical direction in FIG. 11 is larger than the amount of deformation of the piezoelectric material plate 71 in the polarization direction. Therefore, it is possible to reduce the amount of deformation of the piezoelectric material plate 71 in the polarization direction required to give a constant volume change to the liquid chamber 5, and to reduce the required drive voltage. As a result, in the droplet ejection device 700 of the seventh embodiment, the drive voltage can be reduced, and the cost of the device can be reduced.
Energy required for ink ejection can be reduced to improve energy efficiency.

Further, the droplet ejecting apparatus 70 according to the seventh embodiment
At 0, since the third electrode 74 is inserted between the first electrode 2 and the second electrode 3, the device 1 of the first embodiment
As compared with 00, the same electric field strength can be obtained with a lower driving voltage. Therefore, the drive voltage can be further reduced.

Incidentally, the droplet jetting device 70 of the seventh embodiment
In manufacturing 0, the same steps as those in the first embodiment can be used, and the description thereof is omitted.

-Eighth Embodiment- An eighth embodiment in which the droplet ejecting apparatus of the present invention is applied to an ink jet head will be described below with reference to FIGS.

FIGS. 12 and 13 are sectional views showing a droplet ejecting apparatus according to the eighth embodiment. FIG. 12 shows a state where a driving voltage is applied, and FIG. 13 shows a state where no driving voltage is applied. FIG.

As shown in FIGS. 12 and 13, the droplet ejecting apparatus 800 according to the first embodiment is configured by laminating a plurality of (six in this example) green sheets (sheet-like piezoelectric materials) 1a. Piezoelectric material plate 81, a first electrode 82 provided inside the piezoelectric material plate 81, a second electrode 83 provided inside the piezoelectric material plate 81, and a piezoelectric material plate 81 provided inside the piezoelectric material plate 81. Third electrode 84 and a first liquid chamber plate 86 in which a plurality of through holes corresponding to liquid chamber 85 are formed.
And a second liquid chamber plate 87 in which a through hole smaller in diameter than the first liquid chamber plate 6 is formed, and a nozzle plate 89 in which a plurality of nozzles 88 corresponding to each liquid chamber 85 are formed.

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 laminated to provide a plurality of nozzles 88. Liquid chambers 85 are arranged and formed. The piezoelectric material plate 81 is supported by the first liquid chamber plate 86, and is deformed with its supporting position as a fulcrum.

The first electrodes 82 are provided corresponding to the respective liquid chambers 85 and are located at the positions where the piezoelectric material plates 81 supported by the liquid chamber plates 86 are supported. The first electrode 82 is formed by electrically connecting three 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 electrode patterns of the same pattern in the thickness direction of the piezoelectric material plate 81.

The second electrodes 83 are provided corresponding to the respective liquid chambers 85, and are located at substantially the center portions of the respective liquid chambers 85. The second electrode 83 is configured by electrically connecting three layers of electrode patterns formed in the middle of the green sheet 1a. FIG.
As shown in FIG. 13, the second electrode 83 is formed by overlapping electrode patterns of the same pattern in the thickness direction of the piezoelectric material plate 81.

The first electrode 82 as a whole is shown in FIG.
11, the second electrode 83 is generally located above the piezoelectric material plate 81 in FIG.

The third electrodes 84 are provided corresponding to the respective liquid chambers 85, and are arranged between the first electrode 82 and the second electrode 83. The third electrode 84 is formed 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 pattern of electrode patterns in the thickness direction of the piezoelectric material plate 81.

The configuration in which the electrode patterns constituting the first electrode 82, the second electrode 83, and the third electrode 84 are connected to each other and the configuration in which each electrode is drawn out can be arbitrarily selected.

The arrow drawn inside the piezoelectric material plate 81 in FIG. 12 (corresponding to the arrow indicated by the symbol “A” in FIG. 1) indicates the polarization direction of the piezoelectric material plate 81. As shown in each drawing, the piezoelectric material plate 81 is provided between the first electrode 82 and the third electrode 84, and between the second electrode 83 and the third electrode 84.
It is polarized in the direction connecting between

Next, with reference to FIG. 12 and FIG. 13, the operation of ejecting a droplet will be described.

First, the inside of the liquid chamber 85 is filled with ink.
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, 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 match, so that the piezoelectric material plate 81 is deformed so as to extend in any direction in the polarization direction in the direct mode. As shown in FIG. 12, as the piezoelectric material plate 81 is deformed, the area where 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 the second electrode 8.
The directions are opposite to each other across the substantially center of the liquid chamber 5 where the liquid chamber 3 is formed.

Next, the first electrode 82 and the second electrode 8
When the potential of the third electrode 84 is returned to the ground (0 V) while the third electrode 84 is connected to the ground, the piezoelectric material plate 81 returns to the original flat state as shown in FIG.
A predetermined amount of the ink 10 is ejected from the liquid chamber 85 via.

As shown in FIGS. 12 and 13, in the liquid 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 substantially equal to the piezoelectric direction. It is slightly inclined with respect to the plane direction of the material plate 81 (the left-right direction in FIGS. 12 and 13). Therefore, the vertical displacement width of the piezoelectric material plate 81 in FIGS. 12 and 13 is larger than the amount of deformation 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 required for giving a constant volume change to the liquid chamber 5, and to reduce the required driving voltage. As a result, in the droplet ejecting apparatus 800 of the eighth embodiment, the drive voltage is reduced, so that the cost of the apparatus can be reduced, and the energy required for ink ejection is reduced to improve the energy efficiency. be able to.

Hereinafter, the droplet ejecting apparatus 80 according to the eighth embodiment will be described.
0 will be described.

The piezoelectric material plate 81 can be manufactured by laminating and firing a plurality of sheet-like green sheets 1a, which are piezoelectric materials. At this time, the first electrode 2
By printing the material of the second electrode 3 (conductive paste material) in a green sheet shape in a predetermined pattern, the first electrode 82 and the second electrode 83 are simultaneously fired with the green sheet 1a. And a third electrode 84 are formed.

Next, 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, the piezoelectric material plate 81 Perform polarization. Specifically, by connecting the first electrode 82 and the second electrode 83 to a negative potential and connecting the third electrode 83 to a positive potential,
By generating an electric field between the first electrode 82 and the third electrode 84 and between the second electrode 83 and the third electrode 84, the electric field is polarized in the directions of arrows shown in FIGS. Let it.

As shown in FIGS. 12 and 13, the first electrode 82 and the second electrode 83 are provided as a whole at positions deviated in the vertical direction in each figure, and the third electrode 84
Is located between the first electrode 82 and the second electrode 83, the polarization direction is slightly inclined with respect to the surface direction of the piezoelectric material plate 81. An electrode used for polarization;
Since the electrode used to drive the piezoelectric material plate 81 is common,
At the time of driving the piezoelectric material plate 81, the direction of the electric field and the polarization direction match.

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 laminated to produce the droplet ejecting apparatus 800 according to the eighth embodiment. Is done.

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 are interchangeable. Good.

In the first to eighth embodiments, a part of the wall surface of the liquid chamber is constituted by the piezoelectric material plate itself. However, the wall surface of the liquid chamber is constituted by another member, and the wall surface is formed by another member. The driving may be performed by utilizing the deformation of the piezoelectric material plate.

-Ink Jet Printer- An ink jet printer equipped with the droplet ejecting apparatus of the present invention will be described below with reference to FIG. FIG.
FIG. 2 is a perspective view showing a main part of the ink jet printer.

A platen 110 shown in FIG. 14 functions as a sheet conveying means for conveying a sheet as a recording medium.
12, rotatably attached to a frame 113, and is driven by a motor 114. This motor 1
Numeral 14 functions as a driving means of the platen 110, and its driving force is transmitted to the platen 110 via several gears as shown in FIG. The paper 11 is placed on the platen 110.
1 is set, and an ink jet print head is provided to face the platen 110. The liquid droplet ejecting apparatus 100 and the like as an ink jet print head include an ink tank filled with ink and serving as an ink supply tank, and an ink supply path for supplying ink to the liquid droplet ejecting apparatus 100 from the ink tank. It is mounted on a carriage 118 together with an ink supply device 116 composed of a connecting portion connecting the droplet ejecting device and the 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 thereto.
The carriage 22 and the motor 123 for transmitting the driving force constitute a carriage conveying means. And one pulley 1
The motor 22 rotates the motor 22, and the timing belt 124 is fed to move the carriage 22 to the carriage 118 along the platen 110.

The liquid droplet ejecting apparatus of the present invention is not limited to application to an ink jet printer, but can be applied to various printing apparatuses and various coating apparatuses.

The ink jet print head mounted on the carriage is detachably formed even when the liquid ejecting device 100, the ink tank, and the connecting portion including the ink supply path are integrally formed. You may. Further, the configuration may be such that only the droplet ejecting device 100 is mounted on the carriage, or the droplet ejecting device 100 and the connecting portion are mounted.

In short, the droplet ejecting apparatus according to the present invention comprises a carriage on which a print head is mounted, a sheet conveying means for conveying a sheet, and a sheet conveying means for intersecting the sheet conveying direction of the sheet conveying means. The present invention can be employed as a print head of an ink-jet printer including a carriage conveying means for conveying a carriage.

In order to supply ink to the print head, it is necessary to provide an ink tank for storing ink. This ink tank is detachably mounted on the carriage. In this replacement mode, when the print head is fixed to the carriage so as not to be replaced, only the ink tank is replaced. In the case of this replacement mode, the droplet ejecting apparatus is used continuously even after the ink tank is replaced, so that the durability of the droplet ejecting apparatus must be high. On the other hand, the droplet ejecting apparatus and the ink tank are integrated as an ink unit, and the ink unit is provided with a drive signal transmitting connector portion exposing a signal line for driving each nozzle, and the carriage has a head of the printer control device. A drive signal transmission connector portion exposing 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 transmission connector portion is connected to each signal of the drive signal transmission connector portion of the carriage. It is also possible to adopt a mode in which each nozzle is connected to a line and each nozzle is driven by a head drive signal from a printer control device. In the case of this ink unit, if the ink is consumed, the ink unit must be replaced. Therefore, the droplet ejecting device only needs to operate reliably with respect to the amount of ink in the ink tank of the ink unit. The cost is 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 that the structure of the ink unit can be simplified and inexpensive.

When the ink tank is replaceable, the ink supply path between the droplet ejecting device and the ink tank comes into contact with the outside air at the time of replacement, and the outside air is mixed at the time of replacement and the ink discharge capability is impaired. However, such a problem does not occur if the ink unit is embodied in the above-described integral structure.

As the sheet conveying means, in addition to the type for driving the platen, a flat platen is fixed on the conveying path, and a pair of conveying rollers are provided upstream and downstream of the platen, respectively. A type in which a sheet is transported by a transport roller may be used. Further, the print head described above is a print head of a type conveyed by a carriage, but may be of a type capable of simultaneously printing over the entire width of a sheet.

[0137]

As described above, according to the droplet ejecting apparatus of the present invention, since the direction of expansion and contraction of the piezoelectric material plate is inclined with respect to the surface direction of the piezoelectric material plate, the amount of deformation of the piezoelectric material plate is increased. Since the displacement width of the wall surface driven by the piezoelectric material plate can be increased as compared with the above, the driving voltage can be reduced, and a droplet ejecting apparatus with good energy efficiency can be obtained. Further, according to the 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 piezoelectric material plate in comparison with the deformation amount 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 droplet ejecting apparatus according to a first embodiment.

FIG. 2 is a cross-sectional view illustrating a state where ink is filled in a liquid chamber of the droplet ejecting apparatus according to the first embodiment.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a cross-sectional view showing a state where a driving voltage is applied.

FIG. 5 is a cross-sectional view illustrating a state in which application of a driving 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 droplet ejecting apparatus according to a third embodiment.

FIG. 8 is a cross-sectional view illustrating a droplet ejecting apparatus according to a fourth embodiment.

FIG. 9 is a sectional view showing 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 sectional view showing a 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 inkjet printer.

[Explanation of symbols]

 Reference Signs List 1 piezoelectric material plate 1a sheet-like piezoelectric material 2 first electrode (electrode) 3 second electrode (electrode) 5 liquid chamber

Claims (9)

[Claims] 1. A liquid droplet ejecting apparatus, comprising: a piezoelectric material plate for deforming at least a part of a wall surface of a liquid chamber, and ejecting liquid droplets from the liquid chamber by using the deformation of the piezoelectric material plate in a direct mode. In the device, the expansion and contraction direction of the piezoelectric material plate is inclined with respect to the surface direction of the piezoelectric material plate, and the liquid is applied by applying a voltage to the piezoelectric material plate to deform the piezoelectric material plate in the expansion and contraction direction. A droplet ejecting device for ejecting droplets. 2. The droplet ejecting apparatus according to claim 1, wherein the expansion and contraction direction is inclined at an angle of 10 to 70 degrees with respect to a plane direction of the piezoelectric material plate. 3. A droplet ejecting apparatus, comprising: a piezoelectric material plate for deforming at least a part of a wall surface of a liquid chamber, and ejecting liquid droplets from the liquid chamber by deforming 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 droplet is ejected by the deformation of the piezoelectric material plate in the polarization direction due to the application of a voltage to the piezoelectric material plate. A droplet ejecting apparatus characterized by the above-mentioned. 4. The liquid droplet ejecting apparatus according to claim 3, wherein the polarization direction is inclined at an angle of 10 to 70 degrees with respect to a plane direction of the piezoelectric material plate. 5. 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 a direction opposite to each other. The droplet ejecting apparatus according to any one of claims 1 to 4, wherein 6. The droplet ejecting apparatus according to claim 1, wherein a direction of polarization of the piezoelectric material plate and a direction of an electric field applied to the piezoelectric material plate are substantially the same. . 7. The droplet ejecting apparatus according to claim 1, wherein an electrode for applying an electric field to the piezoelectric material plate is provided inside the piezoelectric material plate. 8. The droplet ejecting apparatus according to claim 1, wherein the piezoelectric material plate is formed by laminating a plurality of sheet-shaped piezoelectric materials. 9. The apparatus according to claim 8, wherein the electrode is formed on a surface of the piezoelectric material plate.