JP2004082623A - Liquid ejection head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid ejection head in which rigidity of a bulkhead sectioning pressure generating chambers at a high density can be enhanced. <P>SOLUTION: The liquid ejection head comprises a substrate 10 having a plurality of recesses for forming a plurality of pressure generating chambers 12 on one side face, and a resilient film 50 covering the recesses in the substrate and having one side face for forming the pressure generating chambers. A plurality of piezoelectric oscillators are formed in the regions corresponding to respective pressure generating chambers on the other side of the resilient film. Each piezoelectric oscillator has a lower electrode layer 60, a piezoelectric layer 70 and an upper electrode layer 80. Furthermore, an intermediary lining part 330 including at least one of the piezoelectric layer 70 and the upper electrode layer 80 is formed in each region on the other side face of the resilient film corresponding to the bulkhead 11 between adjacent pressure generating chambers. On one side face of a lining member 110, a recess 112 covering each piezoelectric oscillator is provided so that variation thereof is not impeded and the partition wall 111 between the recesses of the lining member is arranged to abut against the intermediary lining part 330. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid ejecting head that discharges a liquid droplet from a nozzle opening by expanding and contracting a part of a pressure generating chamber communicating with a nozzle opening by an actuator that bends and vibrates.
[0002]
[Prior art]
The liquid ejecting head has a piezoelectric vibration type that pressurizes a liquid such as ink by mechanically deforming the pressure generating chamber, and a heating element is provided in the pressure generating chamber, and the pressure of the bubbles generated by the heat of the heating element is used to form the ink. There are two types, such as a bubble jet type for pressurizing a liquid such as the above.
[0003]
The piezoelectric vibration type liquid ejecting head further includes a longitudinal vibration type liquid ejecting head using a piezoelectric vibrator displaced in the longitudinal direction and a flexible liquid ejecting head using a flexurally displaced piezoelectric vibrator. Classified into types.
[0004]
The vertical vibration type liquid ejecting head can drive at high speed and eject liquid droplets at a high density. However, when manufacturing a vertical vibration type liquid jet head, machining of the piezoelectric vibrator involves a cutting operation. Further, when the piezoelectric vibrator is fixed to the pressure generating chamber, a three-dimensional assembling operation is required, so that there is a problem that the number of manufacturing steps is increased.
[0005]
On the other hand, a flexible liquid jet head uses a silicon single crystal substrate as a base material, forms channels such as pressure generating chambers and reservoirs by anisotropic etching, and uses a piezoelectric vibrator as a piezoelectric material. Since the elastic film can be formed extremely thin and the pressure generating chamber and the piezoelectric vibrator can be formed with high precision by the method of forming the film by the film forming technology such as the sputtering, the opening area of the pressure generating chamber is made as small as possible and the liquid is formed. It is possible to improve the droplet ejection density.
[0006]
However, when trying to increase the nozzle array density in the flexible liquid jet head, the wall thickness of the partition that partitions the pressure generating chamber must be reduced, and the rigidity of the partition that partitions the pressure generating chamber decreases, and There are problems such as occurrence of talk and defective ejection of ink droplets.
[0007]
The invention described in Japanese Patent Application Laid-Open No. 11-291497 discloses an ink jet recording head and an ink jet recording head that can increase the rigidity of the partition that partitions the pressure generating chamber without increasing the thickness of the partition that partitions the pressure generating chamber. The present invention provides an expression recording device.
[0008]
Specifically, in the invention described in Japanese Patent Application Laid-Open No. H11-291497, as shown in FIG. 11, the flow path forming substrate 510 is joined to the piezoelectric vibrator 700 side from a space that does not hinder its movement. A backing member 610 having a partition wall 611 for partitioning the concave portion 612 is fixed to the flow path forming substrate 510 such that the partition wall 611 faces the partition wall 511 of the flow path forming substrate 510, and the piezoelectric member at the time of discharging ink droplets. The displacement of the body active part is also received by the partition wall 611 of the backing material 610, and the deflection of the partition wall 511 of the flow path forming substrate 510 is suppressed.
[0009]
[Problems to be solved by the invention]
The invention described in JP-A-11-291497 has an effect of remarkably suppressing the deflection of the partition wall 511 of the flow path forming substrate 510, and is an extremely useful technique.
[0010]
However, in recent years, it has been required to further increase the recording density (nozzle array density). In that case, the arrangement of the nozzles and the arrangement of the pressure generating chambers are further increased.
[0011]
When the arrangement of the pressure generating chambers is high, it becomes difficult to position the partition wall 611 of the backing material 610 so as to face the partition 511 of the flow path forming substrate 510. In a state where the facing relationship between the partition wall 611 of the backing material 610 and the partition 511 of the flow path forming substrate 510 is not ensured, the deflection of the partition 511 of the flow path forming substrate 510 may not be sufficiently suppressed. Further, when a displacement between the partition wall 611 of the backing material 610 and the partition wall 511 of the flow path forming substrate 510 occurs, the deformation of the elastic film by the piezoelectric vibrator may be hindered.
[0012]
The present invention has been made in view of such a point, and in a case where pressure generating chambers are arranged at higher density, an ink jet recording head capable of increasing the rigidity of a partition partitioning the pressure generating chambers In general, it is an object to provide a liquid jet head.
[0013]
[Means for Solving the Problems]
The present invention provides a substrate having a plurality of concave portions for forming a plurality of pressure generating chambers on one side, an elastic film having one side forming a pressure generating chamber covering the concave portion of the substrate, and another side of the elastic film. A plurality of piezoelectric vibrators formed in a region corresponding to each pressure generating chamber, and each piezoelectric vibrator has a lower electrode layer, a piezoelectric layer, and an upper electrode layer, and is adjacent to each other. In each region on the other side surface of the elastic film corresponding to the partition wall between the pressure generating chambers, a backing mediating portion including at least one of the piezoelectric layer and the upper electrode layer is formed, and each of the backing mediating portions is not hindered from changing the piezoelectric vibrator. The liquid ejecting head is characterized in that a backing member having a concave portion covering the piezoelectric vibrator on one side surface is arranged such that a partition wall between the concave portions of the backing member comes into contact with the intermediate backing portion.
[0014]
According to the present invention, the displacement of the piezoelectric vibrator is effectively received by the partition wall of the backing member, and the deflection of the partition wall of the substrate is suppressed, while the vibration characteristic of the elastic film facing each pressure generating chamber is reduced. It is not changed by the partition wall. In particular, even when the pressure generating chambers are arranged at a higher density, the partition wall of the backing member is opposed to the partition wall of the substrate via the backing mediation part, so that the placement error of the partition wall of the backing member is reduced. Can significantly reduce the effect on the rigidity reinforcement of the partition walls.
[0015]
Specifically, when the width of the pressure generating chamber is about 70 μm and the width of the partition between the pressure generating chambers is about 15 μm, the invention described in Japanese Patent Application Laid-Open No. If there is an error in the positional relationship between the material and the partition wall, the effect of suppressing the deflection of the partition wall of the substrate is greatly reduced. Further, in the invention described in Japanese Patent Application Laid-Open No. 11-291497, the variation in the width of the partition wall of the backing material tends to be linked to the variation in the effect of suppressing the deflection of the partition wall.
[0016]
However, according to the feature of the present invention, even if there is a small error in the arrangement of the partition wall of the backing member with respect to the partition wall of the substrate, the partition wall of the backing member can have a sufficient deflection suppressing effect via the backing mediating portion. And crosstalk between the pressure generating chambers can be significantly prevented.
[0017]
In addition, it is preferable that the partition wall of the backing member is adhered to the backing mediating portion. Alternatively, it is preferable that the partition wall of the backing member is fixed to the backing mediation portion by the bending force of the backing member itself.
[0018]
Preferably, the backing mediator includes both a piezoelectric layer and an upper electrode layer individually formed corresponding to each partition between the pressure generating chambers.
[0019]
More preferably, the lower electrode layer of each piezoelectric vibrator is formed in common, while the piezoelectric layer and upper electrode layer of each piezoelectric vibrator are formed separately for each pressure generating chamber, and Has a piezoelectric layer and an upper electrode layer which are individually formed corresponding to each partition between the lower electrode layer and the pressure generating chamber of each piezoelectric vibrator.
[0020]
More preferably, each piezoelectric vibrator has an insulator layer above the upper electrode layer, and each backing mediator also has an insulator layer above the upper electrode layer. Furthermore, each piezoelectric vibrator may have a lead electrode layer above the insulator layer, and each backing mediator may have a lead electrode layer above the insulator layer.
[0021]
Also, preferably, the partition wall of the backing member has a communication portion that connects the concave portions of the adjacent backing members. In this case, the pressure fluctuation in each recess is reduced.
[0022]
Preferably, the width of the concave portion of the backing member is smaller than the width of the pressure generating chamber. In this case, the rigidity of the backing member itself can be increased as compared with the invention described in JP-A-11-291497. Accordingly, the handling of the backing member is facilitated, and the step of bonding the nozzle plate or the like to the substrate to which the backing member is fixed is further facilitated.
[0023]
Preferably, the depth of the concave portion of the backing member is not less than 5 μm and not more than の of the width of the pressure generating chamber. In this case, the rigidity of the backing member can be sufficiently ensured, and there is no possibility that the backing member contacts the piezoelectric vibrator.
[0024]
Further, preferably, the concave portion of the backing member is sealed with a dry fluid sealed therein. In this case, the durability of the piezoelectric vibrator is improved.
[0025]
Preferably, the substrate and the backing member are made of the same material. In this case, deformation due to joining of the backing member or the like is prevented.
[0026]
Preferably, the substrate is formed of a silicon single crystal substrate, the pressure generating chamber is formed by anisotropic etching, and the lower electrode layer, the piezoelectric layer, and the upper electrode layer are formed by film formation and lithography. In this case, the formation of the piezoelectric vibrator and the formation of the backing mediation portion can be easily performed simultaneously.
[0027]
According to another aspect of the invention, there is provided a liquid ejecting apparatus including: a liquid ejecting head having any of the features described above; and a control unit that drives a piezoelectric vibrator of the liquid ejecting head.
[0028]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0029]
FIG. 1 is an exploded perspective view showing an ink jet recording head according to a first embodiment of the liquid ejecting head of the present invention. FIG. 2 is a diagram showing a cross-sectional structure in a longitudinal direction and a width direction of the pressure generating chamber.
[0030]
As shown in FIGS. 1 and 2, the flow path forming substrate 10 is formed of a silicon single crystal substrate having a plane orientation (110) in the present embodiment. As the flow path forming substrate 10, a substrate having a thickness of about 50 to 300 μm is generally used according to the nozzle array density. When the nozzle array density is 360 dpi, the thickness of the flow path forming substrate 10 is preferably about 50 to 100 μm, and more preferably about 70 μm. This is because the arrangement density can be increased while maintaining the rigidity of the partition wall between the adjacent pressure generating chambers.
[0031]
One surface of the flow path forming substrate 10 is an opening surface, and the other surface is formed with a 0.5 to 2 μm thick elastic film 50 made of silicon dioxide formed in advance by thermal oxidation.
[0032]
On the other hand, two rows of pressure generating chambers 12 divided by a plurality of partition walls 11 are formed on the opening surface of the flow path forming substrate 10 by anisotropic etching of a silicon single crystal substrate. A reservoir 14 arranged in a substantially U-shape so as to surround three sides of a row 13 of the generation chambers 12 and an ink supply port 15 for communicating each pressure generation chamber 12 and the reservoir 14 with a constant fluid resistance are formed. I have. In addition, an ink introduction hole 16 for supplying ink to the reservoir 14 from the outside is formed at a substantially central portion of the reservoir 14.
[0033]
Here, in the anisotropic etching, when the silicon single crystal substrate is immersed in an alkaline solution such as KOH, it is gradually eroded, and the first (111) plane perpendicular to the (110) plane and the first (111) plane are formed. A second (111) plane that forms an angle of about 70 degrees with the (111) plane and forms an angle of about 35 degrees with the (110) plane appears, and is compared with the etching rate of the (110) plane by (111). The etching is performed using the property that the etching rate of the surface is about 1/180. By such anisotropic etching, precision processing can be performed based on depth processing of a parallelogram formed by two first (111) surfaces and two oblique second (111) surfaces. , The pressure generating chambers 12 can be arranged at a high density.
[0034]
In the present embodiment, the long side of each pressure generating chamber 12 is formed by the first (111) plane, and the short side is formed by the second (111) plane. The pressure generating chamber 12 is formed by etching until it reaches the elastic film 50 substantially through the flow path forming substrate 10. Here, the amount of the elastic film 50 that is attacked by the alkaline solution for etching the silicon single crystal substrate is extremely small. Each ink supply port 15 communicating with one end of each pressure generating chamber 12 is formed shallower than the pressure generating chamber 12. That is, the ink supply port 15 is formed by partially etching (half-etching) the silicon single crystal substrate in the thickness direction. Note that the half etching is performed by adjusting the etching time.
[0035]
A nozzle plate 18 having a nozzle opening 17 communicating with the ink supply port 15 of each pressure generating chamber 12 on the side opposite to the ink supply port 15 is provided on the opening side of the flow path forming substrate 10 with an adhesive, a heat-sealing film, or the like. Is fixed through. The nozzle plate 18 has a thickness of, for example, 0.05 to 1 mm, a coefficient of linear expansion of 300 ° C. or less, for example, 2.5 to 4.5 [× 10 ^-6 / ° C] or non-rust steel. The nozzle plate 18 entirely covers one surface of the flow path forming substrate 10 on one surface, and also serves as a reinforcing plate for protecting the silicon single crystal substrate from impact and external force.
[0036]
Here, the size of the pressure generating chamber 12 that applies the ink droplet ejection pressure to the ink and the size of the nozzle opening 17 that ejects the ink droplet are optimized according to the amount of the ejected ink droplet, the ejection speed, and the ejection frequency. You. For example, when recording 360 ink droplets per inch, the nozzle openings 17 need to be formed with a diameter of 10 to 30 μm with high accuracy.
[0037]
On the other hand, the lower electrode film 60 having a thickness of, for example, about 0.5 μm and the piezoelectric film having a thickness of, for example, about 1 μm are formed on the elastic film 50 on the side opposite to the opening surface of the flow path forming substrate 10. A piezoelectric vibrator (piezoelectric element) 300 is formed by laminating a layer 70 and an upper electrode film 80 having a thickness of, for example, about 0.1 μm by a process described later. Here, the piezoelectric vibrator 300 refers to a portion including the lower electrode film 60, the piezoelectric film 70, and the upper electrode film 80.
[0038]
Generally, one of the electrodes of the piezoelectric vibrator 300 is used as a common electrode, and the other electrode and the piezoelectric film 70 are patterned for each of the pressure generating chambers 12. A portion which is constituted by one of the patterned electrodes and the piezoelectric film 70 and in which a piezoelectric strain is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion 320. In the present embodiment, the lower electrode film 60 is a common electrode of the piezoelectric vibrator 300, and the upper electrode film 80 is an individual electrode of the piezoelectric vibrator 300. However, there is no problem even if this is reversed for the sake of the drive circuit and wiring. In any case, the piezoelectric active portion is formed for each pressure generating chamber. In the example described above, the elastic film 50 and the lower electrode film 60 function as a diaphragm, but the lower electrode film may also serve as the elastic film.
[0039]
In the present embodiment, the piezoelectric film 70 and the upper electrode film 80 are patterned in a region facing the pressure generating chamber 12 to constitute the piezoelectric active portion 320, and constitute the piezoelectric active portion 320. The piezoelectric film 70 and the upper electrode film 80 are continuously extended to a region facing the ink supply port 15. In addition, a lead electrode 100 is connected to the upper electrode film 80 in a region facing the reservoir 14 via a contact hole 90a described later.
[0040]
In the present embodiment, the piezoelectric film 70 and the upper electrode film 80 are also patterned in a region of the pressure generating chamber 12 that faces the partition 11, and the piezoelectric film 70 and the upper electrode film 80 are also connected to the ink supply port. It extends continuously to a region facing the 15 partition walls. However, a contact hole 90a, which will be described later, is not provided on the upper electrode film 80 patterned in a region of the pressure generating chamber 12 facing the partition 11, so that the upper electrode film 80 (and the piezoelectric film 70) is made of a piezoelectric material. Does not constitute a body active part.
[0041]
Here, a process of forming the piezoelectric film 70 and the like on the flow path forming substrate 10 made of a silicon single crystal substrate will be described with reference to FIGS.
[0042]
As shown in FIG. 3A, first, a silicon single crystal substrate wafer serving as the flow path forming substrate 10 is thermally oxidized in a diffusion furnace at about 1100 ° C. to form an elastic film 50 made of silicon dioxide.
[0043]
Further, a film of insulating zirconia or the like may be formed on the elastic film 50 to be a part of the elastic film 50.
[0044]
Next, as shown in FIG. 3B, the lower electrode film 60 is formed by sputtering. Pt, Ir, and the like are preferable as the material of the lower electrode film 60. This is because the piezoelectric film 70 described later, which is formed by sputtering or a sol-gel method, needs to be crystallized by firing at a temperature of about 600 to 1000 ° C. in an air atmosphere or an oxygen atmosphere after the film formation. It is. That is, the material of the lower electrode film 60 must be able to maintain conductivity at such a high temperature and in an oxidizing atmosphere. In particular, when PZT is used for the piezoelectric film 70, the conductivity of the material by diffusion of PbO is increased. It is desirable that there is little change in sex, and Pt is preferred for these reasons.
[0045]
Next, as shown in FIG. 3C, a piezoelectric film 70 is formed. Sputtering can be used to form the piezoelectric film 70. In this embodiment, however, a so-called sol in which a metal organic substance is dissolved and dispersed in a solvent is applied, dried, gelled, and further fired at a high temperature. A so-called sol-gel method is used to obtain a piezoelectric film 70 made of a metal oxide. As a material for the piezoelectric film 70, a lead zirconate titanate (PZT) -based material is suitable when used in an ink jet recording head.
[0046]
Next, as shown in FIG. 3D, an upper electrode film 80 is formed. The upper electrode film 80 only needs to be a material having high conductivity, and many metals such as Al, Au, Ni, Pt, Ir, and Cu, and a conductive oxide can be used. In this embodiment, Pt is formed by sputtering.
[0047]
Next, as shown in FIG. 3 (e), a piezoelectric vibrator is disposed at a substantially central position of each pressure generating chamber 12, and at the same time, a backing mediation is made at a position facing the partition wall of each pressure generating chamber 12. The upper electrode film 80 and the piezoelectric film 70 are patterned so as to arrange the portions.
[0048]
FIG. 3E shows a case where the piezoelectric film 70 is patterned with the same pattern as the upper electrode film 80. However, as described above, the piezoelectric film 70 does not necessarily need to be patterned. This is because when a voltage is applied using the pattern of the upper electrode film 80 as an individual electrode, an electric field is applied only between each upper electrode film 80 and the lower electrode film 60 which is a common electrode, and the other portions are not applied. This has no effect. However, in this case, it is necessary to apply a large voltage to obtain the same excluded volume. Therefore, it is preferable that the piezoelectric film 70 is also patterned.
[0049]
After that, the lower electrode film 60 may be patterned to remove unnecessary portions, for example, the vicinity of the inside of the edge on both sides in the width direction of the pressure generating chamber 12. The removal of the lower electrode film 60 is not necessarily performed, and when it is removed, the thickness may be reduced without removing all.
[0050]
Here, the patterning is performed by forming a resist pattern and then performing etching or the like.
[0051]
The resist pattern is formed by applying a negative resist by spin coating or the like, and performing exposure, development, and baking using a mask having a predetermined shape. Of course, a positive resist may be used instead of the negative resist.
[0052]
The etching is performed using a dry etching device, for example, an ion milling device. After the etching, the resist pattern is removed using an ashing device or the like.
[0053]
As the dry etching method, a reactive etching method or the like may be used in addition to the ion milling method. It is also possible to use wet etching instead of dry etching, but it is preferable to use dry etching because patterning accuracy is somewhat inferior to dry etching and the material of the upper electrode film 80 is limited. .
[0054]
Next, as shown in FIG. 4A, an insulator layer 90 is formed so as to cover the periphery of the upper electrode film 80 and the side surfaces of the piezoelectric film 70. In this embodiment, a negative photosensitive polyimide is used as a material of the insulator layer 90.
[0055]
Next, as shown in FIG. 4B, by patterning the insulator layer 90, a contact hole is formed in a portion facing the ink supply port 15 above the upper electrode 80 provided facing the pressure generating chamber 12. 90a is formed. The contact hole 90 a is for connecting a lead electrode 100 described later and the upper electrode film 80.
[0056]
Next, for example, a conductor such as Cr-Au is formed on the entire surface, and then patterned to form a portion facing the ink supply port 15 above the upper electrode 80 provided facing the pressure generating chamber 12. The lead electrode 100 is formed.
[0057]
Needless to say, the lead electrode can also be formed on the entire insulator layer 90 above the upper electrode film 80 provided so as to face the partition 11 of the pressure generating chamber 12. Alternatively, after removing the insulator layer 90 above the upper electrode film 80 provided to face the partition 11 of the pressure generating chamber 12 by patterning the insulator layer 90, the insulating layer 90 is opposed to the partition 11 of the pressure generating chamber 12. A lead electrode may be formed above the provided upper electrode film 80. In these cases, the backing mediator also includes the lead electrode.
[0058]
The above is the film forming process. After forming the film in this manner, as shown in FIG. 4C, the silicon single crystal substrate is anisotropically etched with the above-described alkali solution to form the pressure generating chamber 12 and the like.
[0059]
In the present embodiment, a backing material 110 is provided on the piezoelectric film active portion side of the elastic film 50. On the elastic film 50 side of this backing material 110, a space g having the same pitch as the partition wall 11 that partitions the pressure generating chamber 12 and not contacting the upper electrode film 80 provided opposite to the pressure generating chamber 12 is secured. It has a partition wall 111 that partitions a recess 112 that can be formed.
[0060]
The partition wall 111 is fixed by an adhesive or the like on the insulator layer 90 (or on the lead electrode 100) on the piezoelectric film 70 and the upper electrode film 80 provided to face the partition 11 of the flow path forming substrate 10. Have been. The backing member 110 may be fixed using the bending of the backing material 110 itself without using an adhesive. For example, when the nozzle plate 18 is adhered to the flow path forming substrate 10 and the flow path forming substrate 10 is bent so as to be concave toward the nozzle plate 18 side, the flow path formation after the nozzle plate 18 is bonded is formed. A flexing force acts on the substrate 10 so as to be concave toward the backing material 110 side. The bending force causes the backing material 110 to bend, and as a result, the backing material 110 can be firmly fixed to the flow path forming substrate 10.
[0061]
Further, one end of the recess 112 may be provided with an opening 113 for drawing out a cable or the like.
[0062]
The size of the concave portion 112 defined in the partition wall 111 of the backing material 110 is not particularly limited as long as it has a size that does not hinder the driving of the piezoelectric active portion. In the present embodiment, the width W1 of the concave portion 112 is selected to be smaller than the width W2 of the pressure generating chamber 12, but does not contact the elastic film 50 in a region facing the pressure generating chamber 12. Therefore, the rigidity of the elastic film 50 is not increased. Further, since the width W1 of the concave portion 112 is selected to be smaller than the width W2 of the pressure generating chamber 12, the partition wall 111 is formed by the piezoelectric film 70, the upper electrode film 80, and the insulator layer 90 (and / or Alternatively, it can be easily positioned so as to surely face the partition 11 through the lead electrode 100). If the depth of the concave portion 112 is 5 μm or more and 以下 or less of the width W2 of the pressure generating chamber 12, the rigidity of the backing material 110 is not reduced and the concave portion 112 and the piezoelectric vibrator 320 are in contact with each other. There is no danger. In the present embodiment, the depth of the concave portion 112 is set to 30 μm.
[0063]
In the above-described series of film formation and anisotropic etching, a large number of chips are simultaneously formed on one wafer, and after the process is completed, the flow path forming substrate 10 having one chip size as shown in FIG. Divide each time. The divided flow path forming substrate 10 is sequentially bonded to the nozzle plate 18 and the backing material 110 to form an ink jet recording head. However, as described above, the backing material 110 may be fixed by a method other than bonding. Thereafter, the ink jet recording head is fixed to the holder 105, mounted on a carriage, and incorporated into the ink jet recording apparatus.
[0064]
With such a configuration, the flexural deformation of the elastic film 50 is caused by partitioning the pressure generating chamber 12 for discharging ink droplets, the piezoelectric film 70 facing the partition 11, the upper electrode film 80, and the insulating layer 90. And the partition wall 111 of the backing material 110, and is limited to the region of the pressure generating chamber 12. This prevents the stress acting on the pressure generating chamber 12 during the ejection of ink droplets from propagating to the partition 11 that partitions the other pressure generating chambers 12, thereby preventing the occurrence of crosstalk.
[0065]
Thus, for example, the flow path forming substrate 10 having a thickness of 15 μm and a depth of 70 μm of the partition wall 11 that partitions the pressure generating chamber 12 using the silicon single crystal substrate, and a thickness of 200 μm, a thickness of 25 μm, When a backing material 110 having a partition wall 111 having a thickness of 30 μm was formed and ink droplets were ejected, the relative displacement due to the deflection at the center of the partition wall 11 defining the pressure generating chamber 12 was 4.3.
[0066]
On the other hand, when the ink droplets were ejected without fixing the backing material 110, the relative displacement due to the deflection at the center of the partition 11 dividing the pressure generating chamber 12 was 4.7.
[0067]
From this, it is clear that according to the embodiment in which the backing material 110 is fixed, the displacement amount of the partition 11 of the pressure generating chamber 12 at the time of discharging the ink droplet is reduced by about 10%.
[0068]
In addition, since the backing material 110 is made of the same material as that of the flow path forming substrate 10, the backing material 110 is caused by the difference in thermal expansion with the nozzle plate 18 made of a different material without causing the bending due to the difference in thermal expansion. In addition, deformation of the entire recording head can be suppressed as compared with a conventional recording head that does not use the backing material 110.
[0069]
The ink jet head thus configured takes in ink from an ink inlet 16 connected to an external ink supply means (not shown), fills the inside with ink from the reservoir 14 to the nozzle opening 17, and then supplies an external drive circuit (not shown). Voltage is applied between the lower electrode film 60 and the upper electrode film 80 via the lead electrode 100 in accordance with the recording signal from the lead electrode 100, and the elastic film 50 and the piezoelectric film 70 are flexibly deformed. The pressure inside increases, and ink droplets are ejected from the nozzle opening 17.
[0070]
Next, FIG. 5 is a diagram showing a cross-sectional structure in a longitudinal direction and a width direction of a pressure generating chamber in an ink jet recording head according to a second embodiment of the present invention.
[0071]
In this embodiment, as shown in FIG. 5, the depth d of the concave portion 112 of the backing material 110 is increased, and the silicone having a low moisture content is provided on the inner side of the concave portion 112 so as not to contact the upper electrode film 80. It is the same as the first embodiment except that the porous material 114 impregnated with oil or the like is loaded, and the opening 113 is sealed with an adhesive 115 by filling with a dry inert gas.
[0072]
According to the present embodiment, the infiltration of air in the external environment can be prevented, the piezoelectric film 70 can be isolated from moisture, and deterioration due to moisture absorption and a decrease in dielectric strength can be prevented.
[0073]
FIG. 6 is an exploded perspective view of an ink jet recording head according to a third embodiment of the present invention, and FIG. 7 is a diagram showing a cross-sectional structure of the pressure generating chamber in the longitudinal direction and the width direction of the present embodiment. It is.
[0074]
In the present embodiment, as shown in the figure, the backing material is constituted by a first backing material 120 and a second backing material 130 fixed to the first backing material 120.
[0075]
In the first backing material 120, a through groove for forming a recess 122 having a space that does not hinder the driving of the piezoelectric active portion is formed in a region facing each pressure generating chamber 12, and is opposite to the through groove. The side is sealed with a second backing material 130. Each of the recesses 122 is partitioned by a partition wall 121, and adjacent recesses 122 are formed at an end of the partition wall 121 on the opposite side to the flow path forming substrate 10 and substantially at the center of the pressure generating chamber 12 in the longitudinal direction. Is provided, and thereby all the recesses 122 are communicated.
[0076]
The material of the first backing material 120 and the second backing material 130 is not particularly limited, but a silicon single crystal substrate, glass ceramic, or the like, which is the same material as the flow path forming substrate 10, can be used.
[0077]
The other basic structure is the same as in each of the above embodiments.
[0078]
With such a configuration, similarly to the above-described embodiments, the stress acting on the pressure generating chamber is prevented from propagating to the partition, and the occurrence of crosstalk is prevented. Further, in the present embodiment, since the piezoelectric active portion is sealed in the concave portion 122 and completely shut off from the outside, it is possible to prevent a malfunction due to the external environment. Further, since each of the recesses 122 is communicated with each other via the communication portion 123, it is possible to absorb pressure fluctuations in each of the recesses 122.
[0079]
In addition, the position where the communication part 123 for communicating each concave part 122 is provided is not limited to the present embodiment, and may be provided at any place of the partition wall 121. However, from the viewpoint of preventing crosstalk, it is preferable that the joint between the insulator layer 90 (or the lead electrode layer 100) at the position facing the partition 11 and the partition wall 121 be as large as possible. It is preferable that the partition wall 121 be formed so as not to face the opposing surface of the insulator layer 90 in the portion.
[0080]
Further, in the present embodiment, the backing material is made of two members in order to facilitate the formation of the communication portion 123, but is not limited to this. For example, both may be formed integrally. Moreover, you may make it comprise a backing material by three or more members.
[0081]
The embodiment of the present invention has been described above, but the basic configuration of the ink jet recording head is not limited to the above-described one.
[0082]
For example, the shape of the backing material is not limited to the above-described embodiment. As shown in FIG. 8, as shown in FIG. 8, a step is provided on the side serving as an end and extended to form a fixing portion 114 for fixing a cable or the like. You may do so.
[0083]
Further, in each of the above-described embodiments, the reservoir 14 is formed together with the pressure generating chambers 12 in the flow path forming substrate 10, but a member forming the common ink chamber may be provided so as to overlap the flow path forming substrate 10. .
[0084]
FIG. 9 shows a partial cross section of the ink jet recording head thus configured. In such an embodiment, the sealing plate 160, the common ink chamber forming plate 170, the thin plate 180, and the ink chamber side plate 190 are provided between the nozzle substrate 18A in which the nozzle openings 17A are formed and the flow path forming substrate 10A. Are provided, and a nozzle communication port 31 that communicates with the pressure generating chamber 12A and the nozzle opening 17A is provided so as to penetrate them. That is, the common ink chamber 32 is defined by the sealing plate 160, the common ink chamber forming plate 170, and the thin plate 180, and each of the pressure generating chambers 12 </ b> A and the common ink chamber 32 The communication is made through a communication hole 33. The sealing plate 160 is also provided with an ink introduction hole 34 for introducing ink from outside into the supply ink chamber 32. Further, a penetrating portion 35 is formed in the ink chamber side plate 190 located between the thin plate 180 and the nozzle substrate 18A at a position facing each of the supply ink chambers 32, and a nozzle opening generated when ink droplets are ejected is formed. The thin wall 180 is allowed to absorb the pressure toward the side opposite to the pressure 17A, so that an unnecessary positive or negative pressure is applied to the other pressure generating chambers via the common ink chamber 32. Can be prevented from being added. Note that the thin plate 180 and the ink chamber side plate 190 may be formed integrally.
[0085]
In this type of ink jet recording head as well, the partition wall of the backing material as described above is arranged in a region opposite to the opening surface of the flow path forming substrate 10A and facing the partition that partitions the pressure generating chamber. By doing so, the deflection of the flow path forming substrate can be suppressed.
[0086]
Further, each of the above embodiments is a thin film type ink jet recording head which can be manufactured by applying a film forming and lithography process, but is not limited to this. For example, various structures such as a structure in which a pressure generating chamber is formed by laminating substrates, a structure in which a piezoelectric film is formed by pasting a green sheet or screen printing, or a structure in which a piezoelectric film is formed by crystal growth. The present invention can be applied to an ink jet recording head.
[0087]
Further, in each of the above-described embodiments, the connection portion between the upper electrode film and the lead electrode may be provided at any position, and may be at any end or the center of the pressure generating chamber.
[0088]
Further, the example in which the insulator layer is provided between the piezoelectric vibrator and the lead electrode has been described. However, the present invention is not limited to this. For example, without providing the insulator layer, an anisotropic conductive film may be formed on each upper electrode. A configuration may be adopted in which this anisotropic conductive film is thermally welded and connected to a lead electrode, or connected using various bonding techniques such as wire bonding.
[0089]
As described above, the present invention can be applied to ink jet recording heads having various structures, as long as the gist of the present invention is not contradicted.
[0090]
Further, the ink jet recording head of each of the embodiments constitutes a part of a recording head unit having an ink flow path communicating with an ink cartridge and the like, and is mounted on the ink jet recording apparatus. FIG. 10 is a schematic diagram showing an example of the ink jet recording apparatus.
[0091]
As shown in FIG. 10, the recording head units 1A and 1B having the ink jet recording heads are provided with detachable cartridges 2A and 2B constituting ink supply means, and a carriage 3 on which the recording head units 1A and 1B are mounted. Is provided on a carriage shaft 5 attached to the apparatus main body 4 so as to be movable in the axial direction. The recording head units 1A and 1B discharge, for example, a black ink composition and a color ink composition, respectively. Each piezoelectric vibrator of the recording head units 1A and 1B is independently driven by the control unit 9.
[0092]
Then, the driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears (not shown) and the timing belt 7, so that the carriage 3 on which the recording head units 1A and 1B are mounted is moved along the carriage shaft 5. You. On the other hand, the apparatus main body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S, which is a recording medium such as paper fed by a paper feed roller (not shown), is wound around the platen 8. It is designed to be transported.
[0093]
Although the above description has been made with respect to an ink jet recording head and an ink jet recording apparatus, the present invention is broadly applied to a liquid ejecting head and a liquid ejecting apparatus in general. As an example of the liquid, in addition to ink, glue, nail polish, chemicals, and the like can be used. Further, the present invention can be applied to an apparatus for manufacturing a color filter in a display such as a liquid crystal.
[0094]
【The invention's effect】
As described above, according to the present invention, the displacement of the piezoelectric vibrator is effectively received by the partition wall of the backing member, and the deflection of the partition wall of the substrate is suppressed. Also, the rigidity of the diaphragm opposed to the above is not increased. In particular, even when the pressure generating chambers are arranged at a higher density, the partition wall of the backing member is opposed to the partition wall of the substrate via the backing mediation part, so that the placement error of the partition wall of the backing member is reduced. Can significantly reduce the effect on the rigidity reinforcement of the partition walls.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an ink jet recording head according to a first embodiment of the present invention.
FIG. 2A is a longitudinal sectional view of a pressure generation chamber of the ink jet recording head according to the first embodiment of the present invention, and FIG. 2B is an arrangement of the pressure generation chamber. It is sectional drawing in a direction.
FIG. 3 is a view showing a thin film manufacturing process according to the first embodiment of the present invention.
FIG. 4 is a diagram showing a thin film manufacturing process according to the first embodiment of the present invention.
FIG. 5A is a longitudinal sectional view of a pressure generating chamber of an ink jet recording head according to a second embodiment of the present invention, and FIG. 5B is an arrangement of the pressure generating chamber. It is sectional drawing in a direction.
FIG. 6 is an exploded perspective view of an ink jet recording head according to a third embodiment of the present invention.
FIG. 7A is a longitudinal sectional view of a pressure generating chamber of an ink jet recording head according to a third embodiment of the present invention, and FIG. 7B is an arrangement of the pressure generating chamber. It is sectional drawing in a direction.
FIG. 8 is a perspective view of a backing material according to another embodiment of the present invention.
FIG. 9 is a cross-sectional view of an ink jet recording head according to another embodiment of the present invention.
FIG. 10 is a schematic diagram of an ink jet recording apparatus according to one embodiment of the present invention.
FIG. 11A is a longitudinal sectional view of a pressure generating chamber of an ink jet recording head described in JP-A-11-291497, and FIG. 11B is an arrangement of the pressure generating chamber. It is sectional drawing in a direction.
[Explanation of symbols]
1A, 2A recording head unit
2A, 2B cartridge
3 carriage
4 Inkjet recording device body
5 Carriage shaft
6 Drive motor
7 Timing belt
8 Platen
9 Control unit
10. Flow path forming substrate
11 Partition wall
12 Pressure generating chamber
14 Reservoir
15 Ink supply port
17 Nozzle opening
18 Nozzle plate
50 elastic membrane
60 Lower electrode film
70 Piezoelectric film
80 Upper electrode film
90 Insulator layer
90a contact hole
100 Lead electrode
110 Backing member
111 partition wall
112 recess
113 opening
114 Porous material
115 adhesive
120 first backing member
121 partition wall
122 recess
123 communication section
130 Second Backing Member
300 Piezoelectric vibrator
320 Piezoelectric active part
330 Backing Mediation Department

Claims (14)

A substrate having a plurality of recesses for forming a plurality of pressure generating chambers on one side,
An elastic film having one side surface forming a pressure generating chamber covering the concave portion of the substrate,
On the other side of the elastic film, a plurality of piezoelectric vibrators formed in a region corresponding to each pressure generating chamber,
With
Each piezoelectric vibrator has a lower electrode layer, a piezoelectric layer, and an upper electrode layer,
In each region on the other side of the elastic film corresponding to the partition wall between the adjacent pressure generating chambers, a backing mediating portion including at least one of the piezoelectric layer and the upper electrode layer is formed,
A backing member having a concave portion on one side covering each piezoelectric vibrator so as not to hinder the fluctuation of each piezoelectric vibrator is arranged such that a partition wall between the concave portions of the backing member abuts on the backing mediating portion. A liquid jet head. The liquid jet head according to claim 1, wherein the partition wall of the backing member is adhered to the backing mediation portion. The liquid ejecting head according to claim 1, wherein the partition wall of the backing member is fixed to the backing mediation portion by a bending force of the backing member itself. 4. The liquid ejecting apparatus according to claim 1, wherein the backing mediating portion includes both a piezoelectric layer and an upper electrode layer individually formed corresponding to each partition between the pressure generating chambers. head. The lower electrode layer of each piezoelectric vibrator is formed in common, while the piezoelectric layer and upper electrode layer of each piezoelectric vibrator are individually formed for each pressure generating chamber,
The backing mediator has a piezoelectric layer and an upper electrode layer which are individually formed corresponding to the lower electrode layer of each piezoelectric vibrator and each partition between the pressure generating chambers. 5. The liquid jet head according to 4. Each piezoelectric vibrator has an insulator layer above the upper electrode layer,
The liquid ejecting head according to claim 5, wherein each of the backing mediating portions also has an insulator layer above the upper electrode layer. Each piezoelectric vibrator has a lead electrode layer above the insulator layer,
7. The liquid jet head according to claim 6, wherein each of the backing mediating portions also has a lead electrode layer above the insulator layer. The liquid jet head according to any one of claims 1 to 7, wherein the partition wall of the backing member has a communicating portion that communicates a recess of an adjacent backing member. 9. The liquid jet head according to claim 1, wherein the width of the concave portion of the backing member is smaller than the width of the pressure generating chamber. 10. The liquid jet head according to claim 1, wherein the depth of the concave portion of the backing member is not less than 5 μm and not more than １ ／ of the width of the pressure generating chamber. The liquid jet head according to any one of claims 1 to 10, wherein the concave portion of the backing member is sealed by being filled with a drying fluid. The liquid ejecting head according to claim 1, wherein the substrate and the backing member are made of the same material. The substrate is made of a silicon single crystal substrate,
The pressure generating chamber is formed by anisotropic etching,
13. The liquid ejecting head according to claim 1, wherein the lower electrode layer, the piezoelectric layer, and the upper electrode layer are formed by film formation and a lithography method. A liquid jet head according to claim 1,
A control unit for driving the piezoelectric vibrator of the liquid jet head,
A liquid ejecting apparatus comprising:

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