JPH0664164A - Ink jet head - Google Patents

Abstract

PURPOSE:To improve ink ejection capacity that utilizes extensional deformation in thickness mode for a piezoelectric ink jet head, and to miniaturize its structure while improving quality and density of printing that is made therewith. CONSTITUTION:This apparatus is an ink jet head that is constructed by interposing a substrate 100 made of piezoelectric material between a first lateral plate 120 and a second lateral plate 130 and by attaching the same under pressure to both the lateral plates. Dummy chambers 103 and pressure chambers 104 are formed alternately to the substrate 100. Driving electrodes 110 for giving flexural deformation to the pressure chambers 104 are provided respectively to the surface and the undersurface of the substrate 100, and ink passage grooves 122 and nozzles 123 are respectively formed to the first lateral plate 120. An ink pool 131 is provided to the second lateral plate 130. The pressure chambers 104 are filled with the ink from the ink pool 131, and in execution of printing, voltage is applied to the driving electrodes 110, making the pressure chambers 104 flexurally deformed, and thereby the ink in the pressure chambers are ejected from the nozzles 123 through the ink passage grooves 122.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer, and more particularly, to a structure of a piezoelectric ink jet head which utilizes the expansion and contraction phenomenon of a piezoelectric material due to a thickness mode to flexural deformation.

[0002]

2. Description of the Related Art An on-demand type system in which a part of a pressure chamber filled with ink is deformed by an electromechanical conversion means of a thickness mode piezoelectric material and the volume of the pressure chamber is drastically reduced to eject ink. A technique relating to the print head is disclosed in, for example, Japanese Patent Publication No. 53-12138.

A technique relating to a shear-mode print head in which a partition wall of a channel-shaped pressure chamber filled with ink is deformed by utilizing the deformation of the piezoelectric element in the shear mode, and ink is ejected by the pressure rise of the pressure chamber caused by the deformation. Are described, for example, in Japanese Patent Laid-Open No. 63-252750.

[0004]

As a prior art of an on-demand type ink jet head using a piezoelectric element, there is a structure described in Japanese Patent Publication No. 53-12138. This technique will be described with reference to FIG. 8 (side view). In the figure, the print head 818 is the base member 8
36, a pressure chamber 837, an ink inlet passage 838, and an outlet passage 839 are formed, a nozzle 852 is formed at the end of the outlet passage, and a pressure chamber that is in continuous communication with the nozzle and an ink reservoir (not shown) is separated from the ink reservoir. Filled with ink
At least a part of the wall of the pressure chamber is converted into an electromechanical converting means 841.
It is a structure that is deformed by.

When not in operation, the static pressure of the ink in the ink reservoir and the surface tension of the ink in the nozzle keep the ink in an equilibrium state. When an electric pulse is applied to the electromechanical conversion means from the electrode wires 848 and 849, the operation of the electromechanical conversion means causes the wall of the pressure chamber to be displaced inward as shown by 847, thereby rapidly reducing the volume of the pressure chamber. Then, a part of the ink inside the pressure chamber is ejected from the nozzle as one ink droplet 822. After the ink droplets are ejected, the volume of the pressure chamber is restored to the initial equilibrium state, and the application of the next electric pulse is waited for.

In the structure according to this technique, the pressure chambers need to be arranged on the same plane in order to form a multi-nozzle print head, and the arrangement pitch of the nozzles for ejecting ink is basically the arrangement pitch of the pressure chambers. Will be decided by. It is technically difficult to obtain a head with high resolution and high print quality by making the nozzle pitch finer, and it is possible to some extent by devising the arrangement of the pressure chambers in a staggered pattern or arranging on a circular arc. Since the difference in pitch is large, the number of nozzles that can be realized is limited and the number of nozzles that can be realized is limited. As the electromechanical converting means, generally, two piezoelectric elements, which are polarized in mutually opposite directions, are laminated, or one of them is replaced by a metal plate. Since the pressure chambers must be assembled one by one, and fine and precise work is required, quality stability and cost problems remain and they are not suitable for mass production.

In order to eliminate this defect, Japanese Patent Laid-Open No. 63-
There has been proposed a print head of a system in which a partition of a pressure chamber is deformed by utilizing a shear mode of a piezoelectric element as described in Japanese Patent No. 252750. An example of this head has a structure as shown in FIG. 9, and a print head 910 can be obtained by quoting the description given in JP-A-63-252750.
Is made of a piezoelectric material polarized in a direction perpendicular to the plane and is composed of a number of parallel ink channels 902.
2 includes ink 904, one nozzle 9 for each flow path
It has a nozzle plate 905 made of 06 at the end.
Channel 902 has a rectangular cross section and is separated by electrically actuated, deformable sidewalls 911 that extend perpendicular to the plane containing the channel axis. The side wall 911 extends over the entire length of the flow path, and electrodes are formed on both side surfaces.
Deformation in a shear mode is possible perpendicular to the channel axis, and the ink pressure in the channel is changed so that ink droplets are ejected from the nozzle. The flow channel 902 is connected to a lateral flow channel 913 connected to an ink reservoir (not shown) by a pipe 914 at an end apart from the nozzle. The printhead 910 has a bottom 920 with electrical connections (not shown) that deform the sidewalls 911.
It is made in the upper LSI chip 916. Ink drops 90
7 is discharged according to a request from the flow path 902, and is attached to the print line 908 on the print surface 909.

In the above-mentioned head, the head itself is finer in the size of print dots and the print resolution is improved as compared with the system of the previous example.
Although it has an advantage that it is suitable for cost reduction, it has a drawback that it has a weaker ink ejection capability than other structures. That is, since the amount of change in volume is obtained by multiplying the minute amount of shear deformation of the side wall by the length of the flow path, a long flow path must be formed in order to eject the required volume of ink droplets. As a result, the flow path resistance to the ink rises, and the ink ejection capability deteriorates. Further, when the pitch of the flow path is narrowed to improve the printing resolution, the width of the flow path and the side wall becomes narrower, the flow path resistance to the ink increases, and the rigidity of the side wall decreases, and the ink ejection capability remarkably decreases. There was a drawback.

The present invention is a print head in which the ink discharge capability is improved by converting the expansion and contraction of the thickness mode of the piezoelectric element into the flexural deformation of the partition of the pressure chamber, and operating the print head. It is an object of the present invention to realize a low-priced inkjet printer system that enables fine pitches and to improve printing quality.

[0010]

In order to solve the above-mentioned problems, a print head of an ink jet printer of the present invention comprises (1) a piezoelectric material having windows forming a plurality of pressure chambers and partition walls dividing the windows. A substrate having a flow path groove for guiding ink from the plurality of pressure chambers and a nozzle for discharging ink by opening the first side plate in close contact with one surface of the substrate; A second side plate which is in close contact with the other surface of the substrate and which has a groove communicating with the chamber for supplying ink, and a pair of opposed surfaces of the plurality of partition walls for piezoelectric driving. By attaching electrodes and applying a drive voltage, the partition walls are flexibly deformed to change the volume of the pressure chamber, and the ink filled in the pressure chamber is ejected from the nozzle. (2) Ejection for ejecting ink Adjacent to the pressure chamber An ink jet head characterized in that a dummy chamber that does not discharge ink is arranged at least on one side of the discharge pressure chamber, and a partition that divides the discharge pressure chamber and the dummy chamber is deformed. .

(3) As a structure for deforming the partition walls, electrodes for piezoelectric drive are attached to a pair of opposing surfaces of the plurality of partition walls, and a driving voltage is applied to the electrodes, whereby both ends of the partition walls are deformed. Direction in a thickness mode to constrain both ends of the partition wall so that the side wall parallel to the surface of the partition wall is shorter than the side perpendicular to it, so that the partition wall is always covered with the surface of the substrate. The volume of the pressure chamber is changed by flexural deformation in the direction (4), both ends of the partition wall are constrained, and the surface of the partition wall on the discharge pressure chamber side and the surface on the dummy chamber side have different shapes. With such a configuration, the ink jet head is characterized in that the partition is constantly bent and deformed in the pressure chamber direction to change the volume of the pressure chamber, and the ink filled in the pressure chamber is ejected from the nozzle.

[0012]

[Action]

(1) In the inkjet head of the present invention, a flat plate is brought into close contact with both surfaces of a substrate of a piezoelectric material having a window divided by a large number of partitions arranged in parallel to press the ink into the space formed by the windows and the partitions. The pressure chambers and the dummy chambers are formed by sequentially forming dummy chambers on both sides or one side of the pressure chambers to prevent pressure interference between the pressure chambers and the pressure chambers adjacent to the pressure chambers. This is a structure in which the partition between the chamber and the chamber is deformed to change the volume of the pressure chamber, and the ink filled in the pressure chamber is ejected from the nozzle through the ink flow path formed on the piezoelectric material substrate or one flat plate. Therefore, according to the structure of the present invention, the nozzle pitch can be set according to the arrangement of the pressure chambers and the dummy chambers. For this reason, in the conventional head that uses the deformation of the thickness mode to change the volume of the pressure chambers, the area of the pressure chambers is too large compared to the nozzle pitch and the arrangement of the pressure chambers becomes too wide, resulting in a nozzle pitch Or, there was a constraint condition that the nozzle pitch and the number were restricted without matching with the number, but with the inkjet head of the present invention, this constraint condition is greatly improved, and a high density inkjet head is provided. be able to.

(2) Further, when a pair of electrodes are attached to opposite surfaces of a partition wall made of a piezoelectric material and a drive voltage is applied, distortion occurs due to expansion and contraction of the thickness mode in the longitudinal direction, but both ends of the partition wall are constrained. If so, the partition wall is flexibly deformed and is bent toward the pressure chamber side or the dummy chamber side. At this time, the amount of bending deformation reaches several times to several tens of times the amount of expansion and contraction (where both ends of the partition are free) depending on the shape and the constraint conditions of both ends.

(3) Here, the process of converting the stress due to the expansion and contraction of the thickness mode in the longitudinal direction of the partition wall of the piezoelectric material into the flexural deformation will be described. In FIG. 10, only the partition wall portion of the piezoelectric member is taken out and the prism 201 is taken out. Coordinate axis x
Taking the polarization direction 202 parallel to the coordinate axis z, the electrodes 204 and 205 are attached to the surface of the prism 201 parallel to the xy plane, and the voltage V is applied between the electrodes 204 and 205 so that the electric field direction 203 coincides with the polarization direction 202. Is applied, the prism 201 causes extension strain s (206) in the x and −x directions. The strain s is represented by s = d ₃₁ × E = d ₃₁ × V / h, where d ₃₁ is the piezoelectric constant of the piezoelectric material. h is the distance between the electrodes. Now, FIG.
When the prism 201 is completely restrained by the plane 208 parallel to the yz plane in the longitudinal direction as shown in (a), the distortion generated in the prism causes the flexural deformation 209. When the approximation calculation is performed using the diagram shown in FIG. 11B, the deformation amount Δy is Δy = (k × tan θ) / 2θ˜ (Δk × k / 2) ^1/2 Δk = d ₃₁ × k × V / h k is the length of the prism, Δk is the amount of extension, V is the applied voltage,
h is the distance between the electrodes. k = 2 (mm), h = 0.
1 (mm), d ₃₁ = 200 × 10 ⁻¹² (m / V), V
When a trial calculation is performed using a typical numerical value of = 20 (V), the amount of extension deformation Δk and the amount of deflection deformation Δy are Δk = 0.08 (μm) and Δy = 8.9 (μm), respectively, and the extension deformation is deflected. When converted into deformation, the amount of deformation can be expanded about 100 times.

In the present invention, since the partition walls are driven by utilizing the effect of expanding the deformation amount generated in the process of converting from expansion and contraction into flexural deformation, the partition walls on both sides of the conventional groove are deformed by the shear mode to form the groove. It is possible to significantly increase the ejection capacity, as compared with the structure in which the volume is changed to eject ink. This is because the expansion of the amount of deformation of the partition wall reduces the size of the entire head including the length of the pressure chamber, enabling a nozzle array of small size and high density, and providing an inkjet head of high print quality and low price. You can In addition, the surplus discharge capacity can further lower the drive voltage, which enables low voltage and low power consumption of the drive circuit and high density integrated circuit, which contributes to downsizing and cost reduction.

(4) In the present invention, a series of compartments having dummy chambers that do not eject ink are arranged on both sides or one side of the pressure chambers that eject ink, and the partition walls between adjacent pressure chambers are deformed. Instead, the partition that is in contact with the pressure chamber and the dummy chamber is always deformed in a certain direction to change the volume of the pressure chamber and eject the ink in the pressure chamber. No pressure interference with the pressure chamber. That is, when the dummy chambers are provided on both sides of the pressure chamber, the nozzle pitch equivalent to that of the head using the conventional shearing mode can be reduced to 3/4 that of the conventional one when the dummy chamber is provided on only one side.

[0017]

First Embodiment (1) A first embodiment of the present invention will be described below with reference to the drawings. The present embodiment is an embodiment of a print head of the type in which the partition of the pressure chamber is deformed by utilizing the conversion of strain due to the thickness mode of the piezoelectric element into flexural deformation. FIG. 1 is an external view of the inkjet head of the present invention. The print head 1, the nozzle 2, the ink droplet 3, the drive electrode lead wire 4, the coupler 5, the ink tube 6, and the recording paper 7.
The print head 1 has a central substrate 100 having a pressure chamber that generates a pressure for ejecting ink, and a first side plate 12 having a groove that is in contact with one surface of the substrate and that guides the ink to the nozzles 2.
0, the second side plate 130 that is in contact with the other surface and has a groove for supplying ink, and is composed of three flat plates. By closely contacting these three flat plates, a pressure chamber, an ink flow path, an ink reservoir, etc. Is formed, and the space is filled with ink.

(2) In FIG. 2, the substrate 100 made of a piezoelectric material.
The number of windows 102 is twice as many as the number of ink nozzles plus one, and their long sides are arranged adjacent to each other.
The first side plate 120 is on one surface and the second side plate 1 is on the other surface.
Close to thirty. Each window 102 has a first side plate 12
0, the second side plate 130 forms an empty chamber, but the windows at both ends are dummy chambers, and the dummy chambers 104 and the pressure chambers 10 are alternately arranged.
The partition walls 105 are arranged so as to be 3.

(3) The first side plate 120 is formed with an ink flow path groove 122 for guiding ink to the end surface of the first side plate 120 on the surface in contact with the substrate 100. One end 122 of the ink flow path groove 122 is formed.
a opens in the vicinity of one end 103a of the pressure chamber 103,
A channel having a nozzle 123 that opens to the outside from the pressure chamber 103 by being in contact with the substrate 100 is formed. Second
The side plate 130 has all the pressure chambers 103 and the dummy chambers 104.
An ink reservoir 131 having an opening communicating with the ends 103b and 104b of the through hole 132, the coupler 13
3. Connected to an external ink tank (not shown) through an ink tube (not shown). Although not shown, the ink is filled not only through the ink tank, the ink tube, the coupler and the ink reservoir but also through the pressure chamber and the dummy chamber to the nozzle at the tip of the ink flow path groove. The nozzle 12 that is the opening of the ink flow path groove 122 of the first side plate 120
End surface 129 with 3 and the end surface 1 on the nozzle side of the substrate 100
09 and the end surface 139 of the second side plate 130 are aligned and polished to stabilize the ejection direction of the ink ejected from the smooth nozzle and the flat nozzle 123.

(4) As shown in FIG. 3A, the partition wall 105 has a cross-section 141 having a side 142 parallel to the surface of the substrate 100 in order to restrict the direction of the flexural deformation to the surface direction of the substrate 100. It is shorter than the side 143 perpendicular to it, and in order to restrict the deformation to the pressure chamber side from the dummy chamber, the partition wall 105 is formed asymmetrically as shown in FIG. The surface 105a of the above is convex, and the surface 105b on the dummy chamber side is concave. A partition wall having such a shape is an example of flexural deformation that occurs in only one direction parallel to the surface.However, when extension stress is applied to the partition wall, flexural deformation always occurs in a certain direction, and the deformation stress is overcome. It goes without saying that another shape may be used as long as it does not break.

(5) FIG. 4 for flexurally deforming the partition wall
The partition wall 105 on one surface of the substrate 100 as shown in FIG.
The drive electrodes 110a and 110b are formed on the upper side of the pressure chamber by sandwiching them to form a drive electrode 110, and the drive electrode 110 is connected to an external drive circuit (not shown) via the on-board wiring 112. To be done. Further, as shown in FIG. 4B, the common electrode 111 is formed on the partition wall 105 on the other side of the substrate 100, and the common electrode 111 is formed on the substrate wiring 1.
It is connected via 13 to a common terminal of an external drive circuit (not shown). When a voltage is applied between the drive electrode 110 and the common electrode 111, the partition wall 105 tries to extend in the longitudinal direction but both ends are constrained, so that the partition wall 105 is flexibly deformed in the direction perpendicular to the longitudinal direction, and the volume of the pressure chamber is rapidly increased. Since the ink is reduced, the ink flows through the ink flow path groove 122 shown in FIG. 2 and is ejected from the nozzle 123 which is the opening. In order to fix the substrate 100, the first side plate 120, and the second side plate 130 closely, the partition wall 1
Except for the part 05, it is bonded with a strong adhesive. However, since the partition 105 is slightly deformed, a flexible adhesive should be used, or ink should not leak to the adjacent pressure chamber or dummy chamber. It is also possible to simply attach a membrane for the purpose of sealing. In addition, in the present embodiment, the example in which the substrate 100 is made of an integral piezoelectric material flat plate is described, but only the partition wall is made of the piezoelectric material and the other parts are bonded by using another member. Needless to say, the same effect can be obtained by assembling the substrate.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings. The structure of the print head in this embodiment is such that the dummy substrate is partially omitted and the arrangement of the pressure chamber and the dummy chamber and the structure of the ink nozzle are changed as shown in FIG. Since the structure sandwiched between the first side plate and the second side plate is basically the same as that described in the first embodiment, only the points different from the first embodiment will be described. FIG. 5 shows the arrangement of the pressure chambers 103 and the dummy chambers 104 on the substrate 100. The arrangement is such that the dummy chambers, the pressure chambers, and the pressure chambers are repeated, and finally the dummy chambers end. FIG. 6 (a) is an installation view of the drive electrode, and FIG. 6 (b)
[Fig. 3] is an installation view of a common electrode on the opposite surface. A drive electrode 153 is installed on one surface of the partition wall 151 between the dummy chamber and the pressure chamber, the drive electrode 153 is connected to an external drive circuit via the on-board wiring 155, and a common electrode is provided on the other surface. 154 is installed, and the common electrode 154 is connected to the common terminal of the drive circuit via the on-board wiring 156. No drive electrode is installed on the partition wall 152 between the adjacent pressure chambers. In this arrangement, the partition wall 15 between the dummy chamber and the pressure chamber
Although the pressure is generated only by the deformation of No. 1, the partition wall 152 between the adjacent pressure chambers is not deformed, but the deformation amount of the partition wall, that is, the volume change amount of the pressure chamber is large as described in the operation principle in the section of the action, which is sufficient. Ink can be ejected.

FIG. 7 shows the ink flow path groove 1 on the first side plate 120.
It is a layout drawing of 61 and 162. Ink channel grooves 161, 1
62 is the same as in the first embodiment in that it opens in the pressure chambers 103, but since the pitches of the pressure chambers 103 are not equal, the nozzles 163 are dummy so that the nozzles 163 have a constant pitch regardless of the position of the pressure chambers 103. Ink channel groove 161, on the chamber side,
It is necessary to transform the middle of 162. The total number of windows in the head having such a configuration is 1.5 times the number of pressure chambers plus one, and the same number of pressure chambers is formed with two-thirds the number of windows as in the first embodiment. It is possible to install four-thirds the pressure chamber in the same area. The print density can be improved as compared with the first embodiment.

As described in the above two embodiments, since the ink jet head having the structure of the present invention has a large deformation of the partition wall as described in the section of the operation, the length of the pressure chamber can be reduced. Therefore, it greatly contributes to miniaturization,
Since the dummy chamber is installed between the pressure chambers, the print quality can be improved without causing mutual interference between the adjacent pressure chambers. Further, the structure of the present invention is such that the three flat plates of the substrate 100, the first side plate 120, and the second side plate 130 are closely contacted on their surfaces,
Since the structure is fixed, the assembling process is simple, and the first side plate 120 and the second side plate 130 may be made of any material as long as it is an insulating material that allows easy processing of the ink flow channel 122 and the ink reservoir 131. Therefore, an industrial plastic material can be used, and the plastic material can be manufactured in a precision molding die to produce a large amount of high-precision, low-cost parts, and thus a low-cost print head can be provided.

[0025]

【The invention's effect】

(1) If the expansion deformation of the thickness mode of the piezoelectric material of the present invention is converted into the flexural deformation, there is an effect of amplifying the deformation amount,
Since the ink ejection pressure is increased, the degree of freedom in driving conditions is improved, and in addition, the pressure chamber can be downsized and the density can be increased. (2) According to the structure of the present invention, since the pressure chambers and the dummy chambers are arranged according to the pitch of the nozzles of the print head, the printing density can be increased, and a printer system with a high printing density is provided. can do. (3) According to the structure of the present invention, since the pressure chambers and the dummy chambers can be arranged in accordance with the pitch of the nozzles of the print head, mutual interference between adjacent pressure chambers is eliminated, and high quality and high print quality are achieved. Printing can be provided. (4) According to the structure of the present invention, two flat plates are closely fixed from both sides to the center of the substrate made of a piezoelectric material, so that the manufacturing of the print head of the piezoelectric ink jet printer can be simplified and the cost of the printer system can be reduced. Contribute to

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an inkjet head of the present invention.

FIG. 2 is an exploded perspective view showing the structure of the first embodiment of the present invention.

FIG. 3A is a perspective view showing a cross section of a partition wall according to the first embodiment of the present invention. FIG. 3B is a plan view of the substrate showing the structure of the partition wall according to the first embodiment of the present invention.

FIG. 4A is a plan view showing an arrangement of a substrate and drive electrodes on a partition wall according to the first embodiment of the present invention. FIG. 3B is a plan view showing the arrangement of the common electrode on the substrate and the partition wall according to the first embodiment of the present invention.

FIG. 5 is a plan view showing an arrangement of pressure chambers and dummy chambers on a substrate according to a second embodiment of the present invention.

FIG. 6A is a plan view showing an arrangement of a substrate and drive electrodes on a partition wall according to a second embodiment of the present invention. FIG. 6B is a plan view showing the arrangement of the common electrode on the substrate and the partition wall according to the second embodiment of the present invention.

FIG. 7 is a plan view showing the arrangement of ink flow channel grooves on the first side plate of the second embodiment of the present invention.

FIG. 8 is a side sectional view showing a structure of a first conventional example.

FIG. 9 is a perspective view showing a structure of a second conventional example.

FIG. 10 is an explanatory diagram of an operation principle of extensional deformation of a piezoelectric material.

FIG. 11A is an explanatory diagram of conversion from extensional deformation of a piezoelectric material to flexural deformation. (B) is an explanatory view for an approximate calculation of the flexural deformation of the piezoelectric material.

[Explanation of symbols]

 1 Print Head 2 Nozzle 3 Ink Drop 4 Drive Electrode Lead Line 5 Coupler 6 Ink Tube 7 Recording Paper 100 Substrate 102 Window 103 Pressure Chamber 104 Dummy Chamber 105 Partition Wall 110 Drive Electrode 111 Common Electrode 112 Substrate Wiring 113 Substrate Wiring 120 1st Side plate 122 Ink channel groove 123 Nozzle 130 Second side plate 131 Ink reservoir 132 Through hole 133 Coupler 153 Drive electrode 154 Common electrode 155 Substrate wiring 156 Substrate wiring 161 Ink channel groove 162 Ink channel groove 163 Nozzle 201 Prismatic column 202 Polarization Direction 203 Electric field direction 204 Electrode 205 Electrode 206 Strain 209 Flexible deformation

Claims (4)

[Claims] 1. A flow channel groove for guiding ink from the plurality of pressure chambers and an opening for ejecting the ink to a substrate having windows for forming the plurality of pressure chambers and partition walls made of a piezoelectric material for partitioning the windows. A first side plate having a nozzle in close contact with one surface of the substrate and an ink reservoir communicating with the plurality of pressure chambers for supplying ink in close contact with the other surface of the substrate. A second side plate is attached, electrodes for piezoelectric drive are attached to a pair of opposing surfaces of the plurality of partition walls, and the partition walls are flexibly deformed by applying a drive voltage to change the volume of the pressure chamber. An ink jet head having a structure in which the ink filled in the pressure chamber is ejected from a nozzle. 2. A dummy chamber, which is adjacent to the pressure chamber that ejects ink and does not eject ink, is arranged on the substrate at least on one side of the pressure chamber, and the pressure chamber and the dummy chamber are arranged. The ink jet head according to claim 1, wherein the partition wall that divides the ink is deformed. 3. A piezoelectric driving electrode is attached to a pair of opposing surfaces of the plurality of partition walls, and a driving voltage is applied to the electrodes to expand and deform in the thickness mode in both end directions of the partition wall, thereby By constraining both ends and making the cross-sectional shape of the partition wall parallel to the surface of the substrate shorter than the side perpendicular to it, the partition wall is always flexibly deformed in the surface direction of the substrate, whereby the volume of the pressure chamber is increased. 2. The structure in which the ink filled in the pressure chamber is discharged from the nozzle by changing
Alternatively, the inkjet head according to claim 2. 4. A piezoelectric driving electrode is attached to a pair of opposing surfaces of the partition wall, and by applying a driving voltage to the electrode, the partition wall is stretched and deformed in a thickness mode in both end directions,
By constraining both ends of the partition wall so that the surface of the partition wall on the pressure chamber side and the surface on the dummy chamber side are different from each other, the partition wall is always flexed and deformed in the direction of the pressure chamber to thereby deform the pressure chamber. The ink jet head according to claim 1 or 2, wherein the ink filled in the pressure chamber is ejected from a nozzle by changing the volume of the ink.