JP5107323B2 - Inkjet head and actuator for inkjet head - Google Patents

Description

  The present invention relates to an inkjet head having a plurality of nozzles for ejecting ink and an actuator for the inkjet head.

  For example, an ink jet head using a piezoelectric actuator as a drive element is disclosed. In this ink jet head, a piezoelectric actuator is formed by processing a plurality of grooves on a rod-shaped PZT plate, and a pressure chamber is formed by this piezoelectric actuator. In addition, a nozzle plate exists at a position facing the pressure chamber, and ink pressurized in the pressure chamber is ejected from the nozzles of the nozzle plate (see, for example, Patent Document 1).

  The piezoelectric actuator serving as the pressure chamber is formed, for example, by machining a groove by means such as cutting using a disk-shaped diamond blade. This groove is formed, for example, about half the size of the PZT plate in the height direction.

  By the way, in recent years, there is an increasing demand for higher resolution of such an ink jet head, and in order to further increase the resolution, it is necessary to form pressure chambers and nozzles at higher density in the ink jet head. For this reason, it is necessary to use a thinner diamond blade to form the groove, but there is a limit to making the diamond blade thinner. Further, it is necessary to strictly control the depth of the groove within a predetermined range, which hinders improvement in product yield.

  An object of the present invention is to provide an ink jet head and an ink jet head actuator capable of realizing high resolution nozzles with a simple structure.

An inkjet head according to an aspect of the present invention includes two piezoelectric members each having a plurality of partitioning pieces protruding in a comb-like shape and arranged to face each other, the plurality of partitioning pieces of one of the piezoelectric members, and the other The plurality of partition pieces of the piezoelectric member are arranged so as to overlap each other , and an electrode is formed at an end surface in the ink discharge direction on the piezoelectric member and at a position avoiding the side wall of the partition piece .

  According to the present invention, it is possible to realize high resolution nozzles with a simple structure.

1 is a perspective view showing an ink jet head according to a first embodiment. Sectional drawing along F2-F2 line of the inkjet head shown in FIG. FIG. 2 is an exploded perspective view of the inkjet head shown in FIG. 1. FIG. 4 is a perspective view showing a piezoelectric member of the ink jet head shown in FIG. 3. FIG. 5 is a cross-sectional view taken along line F5-F5 of the inkjet head shown in FIG. FIG. 2 is a perspective view showing a part of a manufacturing process of the inkjet head shown in FIG. 1. FIG. 2 is a cross-sectional view showing a drive substrate of the inkjet head shown in FIG. 1 cut in the horizontal direction. The perspective view which decomposes | disassembles and shows the inkjet head which concerns on 2nd Embodiment. Sectional drawing along the vertical direction of the inkjet head shown in FIG. Sectional drawing which cut | disconnected and showed the drive board | substrate of the inkjet head shown in FIG. Sectional drawing of the inkjet head concerning 3rd Embodiment.

[First embodiment]
Hereinafter, a first embodiment of an inkjet head will be described with reference to FIGS. 1 to 7. In the figure, arrows X, Y, and Z indicate three directions orthogonal to each other. In each drawing, the configuration is appropriately enlarged, reduced, or omitted for explanation.

  The ink jet head of this embodiment is a so-called share mode shared wall type ink jet head, and is an ink circulation type in which ink is circulated constantly in a pressure chamber built therein.

  As shown in FIGS. 1 to 3, the inkjet head 11 includes a nozzle plate 13 having a plurality of nozzles 12, a plurality of pressure chambers 14 provided so as to correspond to the plurality of nozzles 12, and a plurality of pressure chambers 14, respectively. The common liquid chambers 15 communicating with each other, the ink inflow portion 16 for supplying ink to each pressure chamber 14 via the common liquid chamber 15, and collecting the ink from each pressure chamber 14 via the common liquid chamber 15. An ink outflow portion 17, a substrate 18 on which the ink inflow portion 16, the ink outflow portion 17 and the common liquid chamber 15 are respectively formed, and a printed circuit board 21 provided so as to be sandwiched between the central portions of the substrate 18. I have. The ink inflow portion 16 and the ink outflow portion 17 are provided at positions immediately above the pressure chamber 14.

  The ink inflow portion 16 includes a cylindrical inflow pin 22 and a slit-shaped inflow port 23 formed in the substrate 18. Further, the ink outflow portion 17 has a cylindrical outflow pin 24 and a slit-shaped outflow port 25 formed in the substrate 18.

  The inkjet head 11 is further provided in a pair on a partition piece 26 that partitions the pressure chambers 14, a frame portion 27 that surrounds the pressure chamber 14 and the partition piece 26, and upper and lower surfaces of the partition piece 26. The electrode 28 is provided. The partition piece 26 functions as a drive unit (inkjet head actuator) that applies pressure to the ink in the pressure chamber 14 and ejects ink from the nozzles 12. The inkjet head 11 has a protective film (not shown) that covers the inner surface of the pressure chamber 14 and protects the piezoelectric member 31 and the electrode 28.

  The printed circuit board 21 is provided on the printed wiring board 32, a plurality of driver ICs 33 that are provided on the printed wiring board 32 and drive the operation of the partition piece 26, and are provided on the printed wiring board 32 and are provided with the driver IC 33 and the electrodes 28. And a plurality of wirings 34 for connecting the two. The wiring 34 on the printed circuit board 21 is formed on the printed wiring board 32 so as to correspond to the partition piece 26 on a one-to-one basis. The printed circuit board 21 further has an electrical connection portion (not shown) formed continuously with the wiring 34. The electrical connection portion is provided at, for example, an end portion of the printed wiring board 32 and is used for electrical connection with the electrodes 28 on the upper and lower surfaces of the partition piece 26.

  As shown in FIGS. 3 to 5 and 7, the pressure chamber 14 is provided at a position between the two piezoelectric members 31 arranged to face each other. The piezoelectric member 31 has a comb shape as a whole, and the partition pieces 26 are arranged in a comb-teeth shape.

  The piezoelectric member 31 includes a base portion 35, a plurality of partition pieces 26 protruding from the base portion 35, a plurality of groove portions 36 provided between the partition pieces 26, and a tip portion 26A provided at the tip of the partition piece 26. Have. A predetermined gap D is provided between the distal end portions 26 </ b> A of the plurality of partition pieces 26 of one piezoelectric member 31 and the base portion 35 of the other piezoelectric member 31.

  The piezoelectric member 31 further has a hook-like portion 41, and the hook-like portion 41 protrudes from both end portions in the longitudinal direction L of the base portion 35 at positions outside the plurality of partition pieces 26. The base portion 35 and the hook portion 41 of the piezoelectric member 31 constitute a frame portion 27 that surrounds the pressure chamber 14 and the partition piece 26.

  The plurality of partition pieces 26 of one piezoelectric member 31 and the plurality of partition pieces 26 of the other piezoelectric member 31 are staggered. More specifically, as shown in FIGS. 3 and 7, the piezoelectric members 31 are arranged so as to partially overlap each other in the width direction W orthogonal to the longitudinal direction L thereof. Further, as shown in FIG. 4, the width 3 d of the groove 36 is, for example, about three times the width d of the partition piece 26.

  The piezoelectric member 31 of this embodiment is formed by, for example, laminating two plate-like or sheet-like piezoelectric plates 31a and 31b made of PZT (lead zirconate titanate) in a thickness direction. That is, it is composed of a piezoelectric plate 31a constituting the upper upper half 42a and a piezoelectric plate 31b constituting the lower lower half 42b. In the upper half 42a and the lower half 42b, as shown by arrows, the polarization axis intersects the ink discharge direction and is parallel to the nozzle surface, and the polarization axes are opposite (reverse) directions on the upper side and the lower side. Facing.

Here, PZT is used as the piezoelectric member, but a piezoelectric single crystal material such as LiNbO3 or LiTaO3, or a lead-free piezoelectric material such as KNbO3 may be used.

  With reference to FIG. 5, the operation of the inkjet head 11 of the present embodiment will be described. When the user instructs the printing apparatus equipped with the inkjet head 11 to start printing in a state where the pressure chamber 14 is filled with ink, the control unit of the printing apparatus sends a print signal to the driver IC 33 to the inkjet head 11. Output. Upon receiving the print signal, the driver IC 33 applies a drive pulse voltage to the electrode 28. Thereby, the pair of left and right partitioning pieces 26 are separated from each other so as to bend by performing shear mode deformation. Then, these are returned to the initial positions, and further deformed so as to approach each other as shown by a two-dot chain line in FIG. 5, thereby increasing the pressure in the pressure chamber 14 from the nozzle 12 to the Z axis in the figure. Ink droplets are ejected vigorously in the ink ejection direction along.

  Then, with reference to FIG. 6, the manufacturing process of the inkjet head 11 of this embodiment is demonstrated. First, a plurality of plate-like piezoelectric members 31 are arranged in the thickness direction (Z-axis direction). Then, using a diamond blade, the plurality of piezoelectric members 31 are simultaneously cut to form the grooves 36 collectively. The width of the groove 36 is three times the width of the partition piece 26 formed at the same time.

  For example, the upper and lower surfaces of the piezoelectric member 31 are plated to form the electrodes 28. Since the electrodes 28 may be formed on the upper and lower surfaces that are both end surfaces of the partitioning piece 26 in the ink ejection direction, the electrodes 28 are easier to form than when formed on the side wall of the partitioning piece 26.

  Furthermore, a protective film that covers the inner surface of the pressure chamber 14 is formed to reduce the occurrence of defects in the formation of the electrode 28 and the protective film.

  Further, as a manufacturing method, the electrodes 28 may be formed on the upper and lower surfaces of the piezoelectric member 31 before machining, and may be formed into a shape having a plurality of partition pieces 26 by machining after the electrodes 28 are formed.

  In this way, two piezoelectric members 31 on which the electrodes 28 and the protective film are formed are opposed to each other so that the partition pieces 26 are alternately arranged. At this time, the pair of piezoelectric members 31 are abutted and bonded via the hook-like portion 41. As a result, the drive substrate 43 in which the two piezoelectric members 31 are integrated is formed. The nozzle plate 13 is bonded to one surface of the drive substrate 43. Further, the printed circuit board 21 on which the driver IC 33 is mounted and the wiring 34 is formed is bonded to the other surface of the drive substrate 43. The printed circuit board 21 is bonded to the drive substrate 43 so that the position of the electrical connection portion matches the position of the electrode 28. A substrate 18 in which the ink inflow portion 16, the ink outflow portion 17, and the common liquid chamber 15 are formed is bonded to the drive substrate 43. For example, laser processing is performed on the nozzle plate 13 to form a plurality of nozzles 12, thereby completing the inkjet head 11.

  According to the first embodiment, the inkjet head 11 includes a nozzle plate 13 having a plurality of nozzles 12, a plurality of pressure chambers 14 provided corresponding to the plurality of nozzles 12, and ink that sends ink to the pressure chambers 14. An inflow portion 16, an ink outflow portion 17 that collects ink from the pressure chamber 14, and a partition piece 26 that partitions the plurality of pressure chambers 14 and applies pressure to the ink in the pressure chamber 14 to eject ink from the nozzle 12. The pressure chamber 14 is formed at a position between two piezoelectric members 31 having a plurality of partitioning pieces 26 in a comb-like shape, and the plurality of partitioning pieces 26 of the one piezoelectric member 31 are formed. The plurality of partition pieces 26 of the other piezoelectric member 31 are arranged so as to overlap each other, and an electrode 28 is formed on the end surface of the piezoelectric member 31 in the ink discharge direction.

  According to this configuration, the partition piece 26 of the other piezoelectric member 31 can be disposed between the partition pieces 26 of the one piezoelectric member 31. As a result, the pressure chambers 14 and the nozzles 12 can be arranged at a pitch approximately twice as fine without changing the width of the groove portion between the partition pieces 26. For this reason, the resolution of the inkjet head 11 can be increased with a simple structure. Further, it is not necessary to extremely reduce the width dimension of the partition piece 26 in order to increase the resolution of the inkjet head. For this reason, sufficient rigidity can be ensured for the partitioning piece 26, non-ejection in which ink is not ejected well due to insufficient rigidity, or erroneous ejection in which ink is erroneously ejected by nozzles that are not driven due to insufficient rigidity. Can be prevented.

  The piezoelectric member 31 also serves as a frame portion 27 that surrounds the pressure chamber 14 and the partition piece 26. According to this structure, compared with the case where the frame part 27 is formed separately from the partition piece 26, the structure can be simplified and the number of assembly steps can be reduced.

  The ink inflow portion 16 and the ink outflow portion 17 are provided immediately above the pressure chamber 14. According to this configuration, the ink inflow portion 16 and the ink outflow portion 17 can be arranged in a compact manner, and the entire inkjet head 11 can be reduced in size.

  The piezoelectric member 31 includes a base portion 35 that supports the plurality of partition pieces 26, and a tip end portion 26 </ b> A provided at the tips of the plurality of partition pieces 26, and tip portions 26 </ b> A of the plurality of partition pieces 26 of one piezoelectric member 31. And a base 35 of the other piezoelectric member 31 is provided with a predetermined gap D. In general, when ink is continuously ejected at a high speed with one nozzle, there may be a situation in which the supply of ink to the nozzle and the pressure chamber is not in time. According to the above configuration, since the adjacent pressure chambers 14 communicate with each other via the gap D, ink circulation is improved between the pressure chambers 14. For example, the single nozzle 12 continuously inks at high speed. Can be prevented from running out of ink at the nozzle and the pressure chamber.

  Even if the gap D is provided as in the present embodiment, the discharge pressure does not decrease in the pressure chamber 14. As shown in FIG. 7, the acoustic impedance is different between the pressure chamber 14 and the region where the gap D is provided, and at the boundary B between the pressure chamber 14 and the region where the gap D is provided. This is because the pressure vibration wave transmitted through the ink is reflected toward the pressure chamber 14. For this reason, in the inkjet head 11 of this embodiment, it is not necessary to provide a partition plate in this boundary B, and the structure can be simplified correspondingly.

  Furthermore, according to the configuration of the present embodiment, the electrode 28 is formed on the upper and lower surfaces which are the end surfaces of the piezoelectric member 31 in the ink discharge direction (Z direction), thereby reducing the area where the electrode 28 is exposed in the pressure chamber 14. can do. For this reason, it is possible to simplify the protection process for covering the inner surface of the pressure chamber 14, and it is possible to apply ink having low insulating properties.

  Further, since the electrodes 28 are formed on the upper and lower surfaces which are the main surfaces of the piezoelectric member 31, it is possible to form the electrodes 28 before the process of forming the partition pieces 26. Therefore, it is only necessary to form the electrode 28 by patterning the plate-like piezoelectric member 31 as a base material instead of patterning it into a processed one, so that the electrode 28 can be easily formed without using a special machine. it can.

[Second Embodiment]
Next, a second embodiment of the inkjet head will be described with reference to FIGS. The inkjet head 51 of the second embodiment is different from that of the first embodiment in that the partition piece 52 of one piezoelectric member 31 is in contact with the base 35 of the other piezoelectric member 31, but the other parts Is common to the first embodiment. For this reason, mainly different parts will be described, and common parts will be denoted by common reference numerals and description thereof will be omitted.

  The inkjet head 51 of the second embodiment has the same appearance as that shown in FIG. That is, as shown in FIGS. 8 to 10, the inkjet head 51 includes a nozzle plate 13, a plurality of pressure chambers 14, a common liquid chamber 15, an ink inflow portion 16, an ink outflow portion 17, and an ink inflow portion. 16, a substrate 18, and a printed circuit board 21.

  The inkjet head 51 further includes a partition piece 52 that is a drive unit that applies pressure to the ink in the pressure chamber 14 to eject the ink from the nozzles 12, and a frame portion 27 that surrounds the pressure chamber 14 and the partition piece 52. And electrodes 28 provided on the upper and lower surfaces of the partition piece 52 and a protective film (not shown) that covers the inner surface of the pressure chamber 14.

  The pressure chamber 14 is formed at a position between the two piezoelectric members 31 in which the partition pieces 52 are arranged in a comb-teeth shape. The piezoelectric member 31 includes a base portion 35, a plurality of partition pieces 52 protruding from the base portion 35, a plurality of groove portions 36 provided between the partition pieces 52, a tip portion 52A provided at the tip of the partition piece 52, and a base portion. And a hook-like portion 41 projecting from both ends of the longitudinal direction L of 35. The front end portions 52 </ b> A of the plurality of partition pieces 52 of one piezoelectric member 31 are abutted against the base portion 35 of the other piezoelectric member 31.

  The plurality of partition pieces 52 of one piezoelectric member 31 and the plurality of partition pieces 52 of the other piezoelectric member 31 are staggered, and are disposed so as to overlap each other in the width direction W. Further, the width of the groove 36 is, for example, three times the width of the partition piece 52.

  The piezoelectric member 31 of this embodiment is formed by, for example, laminating two plate-like or sheet-like piezoelectric plates 31a and 31b made of PZT (lead zirconate titanate) in a thickness direction. That is, it is composed of a piezoelectric plate 31a constituting the upper upper half 42a and a piezoelectric plate 31b constituting the lower lower half 42b. In the upper half 42a and the lower half 42b, as shown by arrows, the polarization axis intersects the ink discharge direction and is parallel to the nozzle surface, and the polarization axes are opposite (reverse) directions on the upper side and the lower side. Facing.

Here, PZT is used as the piezoelectric member, but a piezoelectric single crystal material such as LiNbO3 or LiTaO3, or a lead-free piezoelectric material such as KNbO3 may be used.

  With reference to FIG. 8, the operation of the inkjet head 51 of this embodiment will be described. Upon receiving a print signal from the control unit of the printing apparatus, the driver IC 33 applies a drive pulse voltage to the electrode 28. Thereby, as shown by a two-dot chain line in FIG. 8, the pair of left and right partition pieces 52 are separated from each other so as to be curved by performing shear mode deformation. Then, by returning these to the initial position and increasing the pressure in the pressure chamber 14, ink droplets are ejected vigorously from the lower nozzle 12.

  According to the second embodiment, the piezoelectric member 31 includes a base portion 35 that supports the plurality of partition pieces 52 and a tip portion 52 </ b> A that is provided at the tips of the plurality of partition pieces 52. The front end portions 52 </ b> A of the plurality of partition pieces 52 are in contact with the base portion 35 of the other piezoelectric member 31. According to this configuration, the effective width of the pressure chamber 14 can be ensured wider in the inkjet head 51 having the same size as the inkjet head 11 of the first embodiment provided with the gap D. For this reason, the dimension of the width direction W can be made small compared with the inkjet head 11 of 1st Embodiment, and the inkjet head 51 can be reduced in size.

[Third embodiment]
Next, a third embodiment of the inkjet head will be described with reference to FIG. In the inkjet head 61 of the third embodiment, the piezoelectric member 31 is configured by stacking two piezoelectric plates 31a and 31b in the thickness direction (Z direction in the figure) between the electrodes 28 with an electrode 28 therebetween. Although the polarization axis is different from that of the first embodiment in that it is directed in the same direction, other parts are common to the first embodiment. For this reason, mainly different parts will be described, and common parts will be denoted by common reference numerals and description thereof will be omitted.

  In the ink jet head 61 according to the third embodiment, as in the ink jet head 11, the pressure chamber 14 is provided at a position between the two piezoelectric members 31 arranged to face each other. The piezoelectric member 31 has a comb-like shape as a whole, and the partition pieces 26 are arranged in a comb-teeth shape. The plurality of partition pieces 26 of one piezoelectric member 31 and the plurality of partition pieces 26 of the other piezoelectric member 31 are staggered.

  The piezoelectric member 31 of the present embodiment includes, for example, two plate-like or sheet-like piezoelectric plates 31a and 31b made of PZT (lead zirconate titanate) and stacked in the thickness direction with an electrode 28 interposed therebetween. It is formed by bonding. That is, the electrode 28 is disposed at the center in the thickness direction between the piezoelectric plate 31a constituting the upper upper half 42a and the piezoelectric plate 31b constituting the lower lower half 42b. In the upper half 42a and the lower half 42b, as indicated by arrows, the polarization axis intersects the ink ejection direction and is parallel to the nozzle surface, and the polarization axis is directed in the same direction on the upper side and the lower side. Yes. Other configurations are the same as those of the inkjet head 11 according to the first embodiment. Here, PZT is used as the piezoelectric member, but a piezoelectric single crystal material such as LiNbO3 or LiTaO3, or a lead-free piezoelectric material such as KNbO3 may be used.

  In the inkjet head 61 configured as described above, when the user instructs the printing apparatus equipped with the inkjet head 61 to start printing with the pressure chamber 14 filled with ink, the control unit of the printing apparatus A print signal is output to the driver IC 33 to the inkjet head 61. Upon receiving the print signal, the driver IC 33 applies a drive pulse voltage to the electrode 28. Thereby, the pair of left and right partitioning pieces 26 are separated from each other so as to bend by performing shear mode deformation. Then, these are returned to the initial positions, and further deformed so as to approach each other as indicated by a two-dot chain line in FIG. 11, thereby increasing the pressure in the pressure chamber 14, and extending from the nozzle 12 along the Z axis in the figure. Ink droplets are ejected vigorously in the ink ejection direction.

  In the inkjet head 61 according to the present embodiment, the same effects as those of the first embodiment can be obtained. Further, by arranging the electrode 28 at the center of the piezoelectric member 31 in the thickness direction and aligning the polarization directions of the upper half 42a and the lower half 42b, the voltage required for the operation can be kept low. That is, since the voltage required for the operation is determined by the physical size of the distance of the electrode 28, when the electrode 28 is formed on the upper and lower surfaces, the voltage is determined according to the dimension in the thickness direction of the piezoelectric member 31, In this embodiment, by further disposing the electrode 28 between the two piezoelectric plates 31a and 31b, the distance between the electrodes 28 can be shortened by half and the required voltage can be halved.

Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage . In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some constituent elements may be deleted from all the constituent elements shown in the embodiments, or constituent elements over different embodiments may be appropriately combined.
Hereinafter, the invention described in the scope of claims of the present application will be appended.
(1)
A nozzle plate having a plurality of nozzles;
A plurality of pressure chambers provided corresponding to the plurality of nozzles;
An ink inflow portion for sending ink to the plurality of pressure chambers; an ink outflow portion for collecting ink from the plurality of pressure chambers;
A partition piece for partitioning the plurality of pressure chambers and applying pressure to the ink in the pressure chamber to eject ink from the nozzle;
Comprising
The pressure chamber is formed at a position between two piezoelectric members each having a plurality of the partition pieces in a comb-like shape so as to face each other, and the plurality of partition pieces of one piezoelectric member and the other piezoelectric member The plurality of partition pieces are arranged to overlap each other,
An ink-jet head, wherein an electrode is formed on an end face of the piezoelectric member in an ink discharge direction.
(2)
The piezoelectric member has a plane along which the polarization axis intersects the ink ejection direction, and the direction of the polarization axis is reversed between one side and the other side of the ink ejection direction,
The inkjet head according to (1), wherein electrodes are formed on both end faces of the piezoelectric member in the ink discharge direction.
(3)
The piezoelectric member has a pair of piezoelectric bodies whose polarization axes are oriented in the same direction along a plane intersecting the ink ejection direction,
The inkjet head according to (1), wherein electrodes are formed between both end surfaces of the piezoelectric member in the ink discharge direction and between the pair of piezoelectric bodies.
(4)
The piezoelectric member serves as a frame portion surrounding the pressure chamber and the partition piece, and the ink inflow portion and the ink outflow portion are provided directly above the pressure chamber. The inkjet head according to any one of (3).
(5)
The piezoelectric member includes a base portion that supports the plurality of partition pieces, and a tip portion that is provided at the tips of the plurality of partition pieces,
The inkjet head according to (4), wherein a predetermined gap is provided between tip portions of the plurality of partition pieces of one of the piezoelectric members and a base portion of the other piezoelectric member.
(6)
The piezoelectric member includes a base portion that supports the plurality of partition pieces, and a tip portion that is provided at the tips of the plurality of partition pieces,
The inkjet head according to (4), wherein tip ends of the plurality of partition pieces of one of the piezoelectric members are in contact with a base portion of the other piezoelectric member.
(7)
It has two piezoelectric members each having a plurality of partitioning pieces projecting in a comb-like shape and arranged to face each other,
The plurality of partition pieces of one of the piezoelectric members and the plurality of partition pieces of the other piezoelectric member are arranged to overlap each other,
An actuator for an ink jet head, wherein an electrode is formed on an end face of the piezoelectric member in an ink discharge direction.
(8)
The piezoelectric member has a pair of piezoelectric bodies whose polarization axes are oriented in the same direction along a plane intersecting the ink ejection direction,
The inkjet head actuator according to (7), wherein electrodes are formed between both end surfaces of the piezoelectric member in the ink discharge direction and the pair of piezoelectric bodies.
(9)
8. The piezoelectric member serves as a frame portion that surrounds the pressure chamber and the partition piece, and the ink inflow portion and the ink outflow portion are provided immediately above the pressure chamber. Actuator for inkjet head.

DESCRIPTION OF SYMBOLS 11 ... Inkjet head, 12 ... Nozzle, 13 ... Nozzle plate, 14 ... Pressure chamber, 2
6 ... partition piece, 26A ... tip part, 27 ... frame part, 31 ... piezoelectric member, 31a, 31b ... piezoelectric plate, D ... gap, 51 ... inkjet head, 52 ... partition piece, 52A ... tip part.

JP-T-2002-529289

Claims (9)

A nozzle plate having a plurality of nozzles;
A plurality of pressure chambers provided corresponding to the plurality of nozzles;
An ink inflow portion for sending ink to the plurality of pressure chambers; an ink outflow portion for collecting ink from the plurality of pressure chambers;
A partition piece for partitioning the plurality of pressure chambers and applying pressure to the ink in the pressure chamber to eject ink from the nozzle;
Comprising
The pressure chamber is formed at a position between two piezoelectric members each having a plurality of the partition pieces in a comb-like shape so as to face each other, and the plurality of partition pieces of the one piezoelectric member and the other piezoelectric member The plurality of partition pieces are arranged to overlap each other,
Wherein the end face of the ink ejection direction on the piezoelectric member and ink jet head is characterized in that electrodes in a position to avoid the side wall of the partition member is formed. The piezoelectric member has a plane along which the polarization axis intersects the ink ejection direction, and the direction of the polarization axis is reversed between one side and the other side of the ink ejection direction,
2. The ink jet head according to claim 1, wherein electrodes are formed on both end faces of the piezoelectric member in the ink discharge direction. The piezoelectric member has a pair of piezoelectric bodies whose polarization axes are oriented in the same direction along a plane intersecting the ink ejection direction,
The inkjet head according to claim 1, wherein electrodes are formed between both end surfaces of the piezoelectric member in an ink discharge direction and between the pair of piezoelectric bodies.   The piezoelectric member also serves as a frame portion surrounding the pressure chamber and the partition piece, and the ink inflow portion and the ink outflow portion are provided directly above the pressure chamber. The inkjet head according to any one of 3. The piezoelectric member includes a base portion that supports the plurality of partition pieces, and a tip portion that is provided at the tips of the plurality of partition pieces,
The inkjet head according to claim 4, wherein a predetermined gap is provided between tip portions of the plurality of partition pieces of one of the piezoelectric members and a base portion of the other piezoelectric member. The piezoelectric member includes a base portion that supports the plurality of partition pieces, and a tip portion that is provided at the tips of the plurality of partition pieces,
The inkjet head according to claim 4, wherein tip ends of the plurality of partition pieces of one of the piezoelectric members abut against a base of the other piezoelectric member. Each has a plurality of partitioning pieces projecting in a comb-like shape, and has two piezoelectric members arranged to face each other,
The plurality of partition pieces of one of the piezoelectric members and the plurality of partition pieces of the other piezoelectric member are arranged to overlap each other,
Wherein the end face of the ink ejection direction on the piezoelectric member, and an actuator for an ink jet head, characterized in that the electrodes in a position to avoid the side wall of the partition member is formed. The piezoelectric member has a pair of piezoelectric bodies whose polarization axes are oriented in the same direction along a plane intersecting the ink ejection direction,
8. The inkjet head actuator according to claim 7, wherein electrodes are formed between both end faces of the piezoelectric member in the ink discharge direction and between the pair of piezoelectric bodies.   8. The piezoelectric member serves as a frame portion that surrounds the pressure chamber and the partition piece, and the ink inflow portion and the ink outflow portion are provided immediately above the pressure chamber. Actuator for inkjet head.

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