JP4120761B2 - Inkjet recording head and inkjet recording apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
According to the present invention, a part of a pressure generating chamber communicating with a nozzle opening for ejecting ink droplets is constituted by a diaphragm, and a piezoelectric element is formed on the surface of the diaphragm, and ink droplets are ejected by displacement of the piezoelectric element. The present invention relates to an ink jet recording head and an ink jet recording apparatus.
[0002]
[Prior art]
A part of the pressure generation chamber communicating with the nozzle opening for discharging ink droplets is constituted by a vibration plate, and the vibration plate is deformed by a piezoelectric element to pressurize the ink in the pressure generation chamber to discharge ink droplets from the nozzle opening. Two types of ink jet recording heads have been put into practical use: those using a longitudinal vibration mode piezoelectric actuator that extends and contracts in the axial direction of the piezoelectric element, and those using a flexural vibration mode piezoelectric actuator.
[0003]
The former can change the volume of the pressure generation chamber by bringing the end face of the piezoelectric element into contact with the vibration plate, and it is possible to manufacture a head suitable for high-density printing, while the piezoelectric element is arranged in an array of nozzle openings. There is a problem that the manufacturing process is complicated because a difficult process of matching the pitch into a comb-like shape and an operation of positioning and fixing the cut piezoelectric element in the pressure generating chamber are necessary.
[0004]
On the other hand, the latter can flexibly vibrate, although a piezoelectric element can be built on the diaphragm by a relatively simple process of sticking a green sheet of piezoelectric material according to the shape of the pressure generation chamber and firing it. There is a problem that a certain amount of area is required for the use of, and high-density arrangement is difficult.
[0005]
On the other hand, in order to eliminate the inconvenience of the latter recording head, a uniform piezoelectric material layer is formed by a film forming technique over the entire surface of the diaphragm as seen in Japanese Patent Laid-Open No. 5-286131. A material in which a piezoelectric layer is formed so that a material layer is cut into a shape corresponding to a pressure generation chamber by a lithography method and is independent for each pressure generation chamber has been proposed.
[0006]
This eliminates the need to affix the piezoelectric element to the diaphragm, so that not only can the piezoelectric element be created by a precise and simple technique called lithography, but also the thickness of the piezoelectric actuator can be reduced. There is an advantage that high-speed driving is possible.
[0007]
On the other hand, when the piezoelectric element is configured by sputtering of the piezoelectric material in this way, when driven at substantially the same voltage as that formed by firing the green sheet, a high electric field is applied by the thin amount of the piezoelectric element, When moisture is absorbed, there is a problem that the leakage current between the drive electrodes is likely to increase, which eventually leads to dielectric breakdown.
[0008]
In order to solve such a problem, a structure has been proposed in which a sealing substrate having a sealing portion for sealing a piezoelectric element is bonded to a flow path forming substrate in which a pressure generating chamber is formed.
[0009]
[Problems to be solved by the invention]
However, such an ink jet recording head has a problem that the sealing strength is lowered because the sealing substrate is bonded onto the flow path forming substrate on which the piezoelectric elements are patterned. That is, by patterning the piezoelectric element, a step is formed at the joint portion between the flow path forming substrate and the sealing substrate, and thus there is a problem that the sealing substrate cannot be satisfactorily adhered.
[0010]
Furthermore, when the sealing substrate is bonded onto the lead electrode extended from the piezoelectric element, there is a possibility that the adhesive for bonding the flow path forming substrate and the sealing substrate may flow out onto the lead electrode. There is a problem that the mounting strength of the external wiring for driving the lead electrode and the piezoelectric element or the connection wiring connected to the driving circuit is lowered by the adhesive.
[0011]
In view of such circumstances, it is an object of the present invention to provide an ink jet recording head and an ink jet recording apparatus that can satisfactorily join a flow path forming substrate and a sealing substrate.
[0012]
[Means for Solving the Problems]
According to a first aspect of the present invention for solving the above problem, a flow path forming substrate in which a pressure generating chamber communicating with a nozzle opening for discharging ink is defined, and a vibration plate is provided on one side of the flow path forming substrate. In the ink jet recording head comprising a lower electrode, a piezoelectric layer, and a piezoelectric element comprising an upper electrode, a space is formed in a region facing the piezoelectric element on the surface of the flow path forming substrate on the piezoelectric element side. A reservoir forming substrate having a sealing portion that seals the space in a state of securing the space and having a reservoir portion that constitutes at least a part of a common ink chamber of each pressure generating chamber, and the piezoelectric element includes the sealing portion The region where the reservoir forming substrate of the flow path forming substrate is joined to the outside of the flow path forming substrate is a layer that constitutes the piezoelectric element and is a discontinuous layer from the piezoelectric element. Previous to upper layer The upper electrode contact layer having the same height is provided between the piezoelectric element has a discontinuous discontinuous on the electrode film, said containing the discontinuous upper electrode film, wherein the reservoir forming substrate constituting the bonding layer An ink jet recording head characterized by being bonded to an upper electrode film that constitutes an upper electrode of a portion that constitutes a piezoelectric element but is not substantially driven.
[0013]
In the first aspect, since the reservoir forming substrate is bonded to the upper electrode film, the bonding strength is improved and the sealing portion can be reliably sealed. The reservoir forming substrate is bonded to the flow path forming substrate through the bonding layer. In addition, a part of the reservoir forming substrate is bonded to the flow path forming substrate via the piezoelectric element. In addition, the bonding layer can be easily formed, and the height of the bonding layer can be easily adjusted.
[0018]
According to a second aspect of the present invention, there is provided a piezoelectric active portion in which the piezoelectric element is a substantial driving portion and a piezoelectric non-active portion that is at least substantially not driven but has at least a piezoelectric layer continuous from the piezoelectric active portion. It has the door, and the piezoelectric inactive part is in the ink jet recording head of the first aspect, characterized in that is extended from an inside of the sealing portion to the outside of the sealing portion.
[0019]
In the second aspect, since the piezoelectric element in the region to which the reservoir forming substrate is bonded is not driven, the bonded state of the reservoir forming substrate can be favorably maintained.
[0020]
According to a third aspect of the present invention, the region where the reservoir forming substrate of the piezoelectric inactive portion is joined is composed of a lower electrode film constituting a lower electrode of the piezoelectric active portion, and the lower electrode is A discontinuous lower electrode film is provided in the ink jet recording head according to the second aspect.
[0021]
In the third aspect, it is easy to adjust the height of the upper electrode film in the region to which the reservoir forming substrate is bonded.
[0022]
A fourth aspect of the present invention, any one end lead electrodes connected to the external wiring, the first 1 to 3, characterized in that it is electrically connected to the piezoelectric element on the outside of the sealing portion The ink jet recording head according to one embodiment is provided.
[0023]
In the fourth aspect, since the lead electrode is not formed in the region where the reservoir forming substrate is bonded, the bonding strength of the reservoir forming substrate is improved. Further, when the reservoir forming substrate is bonded with an adhesive, the adhesive does not protrude onto the lead electrode, and the wiring can be firmly connected to the lead electrode by wire bonding.
[0024]
A fifth aspect of the present invention is the ink jet recording head according to any one of the first to fourth aspects, wherein the bonding layer is provided independently between the piezoelectric elements. .
[0025]
In the fifth aspect, since the level difference between the surfaces to which the reservoir forming substrate is bonded is substantially eliminated and becomes substantially flat, the reservoir forming substrate can be bonded well.
[0036]
A sixth aspect of the present invention is an ink jet recording apparatus comprising the ink jet recording head according to any one of the first to fifth aspects.
[0037]
In the sixth aspect, it is possible to realize an ink jet recording apparatus that prevents destruction of the head and has improved durability and reliability.
[0038]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments.
[0039]
(Embodiment 1)
FIG. 1 is an exploded perspective view showing an ink jet recording head according to Embodiment 1 of the present invention, and FIG. 2 is a plan view of FIG. 3 is a cross-sectional view taken along the line BB ′ and the line CC ′ of the plan view of FIG.
[0040]
As shown in the drawing, the flow path forming substrate 10 is composed of a silicon single crystal substrate having a plane orientation (110) in this embodiment. As the flow path forming substrate 10, one having a thickness of about 150 to 300 μm is usually used, preferably about 180 to 280 μm, more preferably about 220 μm. This is because the arrangement density can be increased while maintaining the rigidity of the partition between adjacent pressure generating chambers.
[0041]
One surface of the flow path forming substrate 10 is an opening surface, and an elastic film 50 having a thickness of 1 to 2 μm made of silicon dioxide previously formed by thermal oxidation is formed on the other surface.
[0042]
On the other hand, pressure generation chambers 12 partitioned by a plurality of partition walls 11 are arranged in parallel in the width direction on the opening surface of the flow path forming substrate 10 by anisotropic etching of the silicon single crystal substrate. Are formed with a communicating portion 13 that forms part of a reservoir 100 that communicates with a reservoir portion 31 of a reservoir forming substrate 30 (to be described later) and serves as a common ink chamber for each pressure generating chamber 12. It communicates with one end in the longitudinal direction via an ink supply path 14.
[0043]
Here, the anisotropic etching is performed by utilizing the difference in etching rate of the silicon single crystal substrate. For example, in this embodiment, when a silicon single crystal substrate is immersed in an alkaline solution such as KOH, the first (111) plane perpendicular to the (110) plane is gradually eroded, and the first (111) plane. And a second (111) plane that forms an angle of about 70 degrees with the (110) plane and an angle of about 35 degrees appears, and the (111) plane is compared with the etching rate of the (110) plane. This is performed using the property that the etching rate is about 1/180. By this anisotropic etching, precision processing can be performed based on the parallelogram depth processing formed by two first (111) surfaces and two oblique second (111) surfaces. The pressure generating chambers 12 can be arranged with high density.
[0044]
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 generation chamber 12 is formed by etching until it substantially passes through the flow path forming substrate 10 and reaches the elastic film 50. Here, the amount of the elastic film 50 that is affected by the alkaline solution for etching the silicon single crystal substrate is extremely small. In addition, each ink supply path 14 communicating with one end of each pressure generation chamber 12 is formed shallower than the pressure generation chamber 12, and the flow path resistance of the ink flowing into the pressure generation chamber 12 is kept constant. That is, the ink supply path 14 is formed by etching the silicon single crystal substrate halfway in the thickness direction (half etching). Half etching is performed by adjusting the etching time.
[0045]
Further, a nozzle plate 20 having a nozzle opening 21 communicating with the side opposite to the ink supply path 14 of each pressure generating chamber 12 on the opening surface side of the flow path forming substrate 10 is an adhesive, a heat-welded film, or the like. It is fixed through. The nozzle plate 20 has a thickness of, for example, 0.1 to 1 mm and a linear expansion coefficient of 300 ° C. or less, for example, 2.5 to 4.5 [× 10 ⁻⁶ / ° C.], or Made of non-rust steel. The nozzle plate 20 entirely covers one surface of the flow path forming substrate 10 on one surface, and also serves as a reinforcing plate that protects the silicon single crystal substrate from impact and external force. Further, the nozzle plate 20 may be formed of a material having substantially the same thermal expansion coefficient as that of the flow path forming substrate 10. In this case, since the deformation by heat of the flow path forming substrate 10 and the nozzle plate 20 is substantially the same, it can be easily joined using a thermosetting adhesive or the like.
[0046]
Here, the size of the pressure generation chamber 12 that applies ink droplet discharge pressure to the ink and the size of the nozzle opening 21 that discharges the ink droplet are optimized according to the amount of ink droplet to be discharged, the discharge speed, and the discharge frequency. The For example, when recording 360 ink droplets per inch, the nozzle opening 21 needs to be accurately formed with a diameter of several tens of μm.
[0047]
On the other hand, on the elastic film 50 opposite to the opening surface of the flow path forming substrate 10, a lower electrode film 60 having a thickness of, for example, about 0.2 μm and a piezoelectric layer having a thickness of, for example, about 1 μm. 70 and an upper electrode film 80 having a thickness of, for example, about 0.1 μm are laminated by a process described later to constitute the piezoelectric element 300. Here, the piezoelectric element 300 refers to a portion including the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80. In general, one electrode of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each pressure generating chamber 12. In this case, a portion that is configured by any one of the patterned electrodes and the piezoelectric layer 70 and in which piezoelectric distortion is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion 320. In this embodiment, the lower electrode film 60 is a common electrode of the piezoelectric element 300, and the upper electrode film 80 is an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for the convenience of the drive circuit and wiring. In either case, a piezoelectric active part is formed for each pressure generating chamber. Further, here, the piezoelectric element 300 and the vibration plate that is displaced by driving the piezoelectric element 300 are collectively referred to as a piezoelectric actuator.
[0048]
In addition, a lead electrode 90 made of, for example, gold (Au) or the like extends from the upper electrode film 80 to the elastic film 50 in the vicinity of one end in the longitudinal direction of the piezoelectric element 300. It is electrically connected to a drive circuit 110 described later via wiring.
[0049]
On the flow path forming substrate 10 on which the piezoelectric element 300 is formed, a reservoir forming substrate 30 having a reservoir portion 31 constituting at least a part of the reservoir 100 is joined. In this embodiment, the reservoir portion 31 is formed across the reservoir forming substrate 30 in the thickness direction and across the width direction of the pressure generating chamber 12, and as described above, the communication portion of the flow path forming substrate 10 is formed. The reservoir 100 is connected to the pressure generation chamber 12 and serves as a common ink chamber for the pressure generation chambers 12.
[0050]
Further, in a region facing the piezoelectric element 300 of the reservoir forming substrate 30, a piezoelectric element holding portion 32 capable of sealing the space is provided in a state where a space that does not hinder the movement of the piezoelectric element 300 is secured. The element 300 is sealed in the piezoelectric element holding portion 32. In the present embodiment, the piezoelectric element holding portion 32 is provided for each row of the piezoelectric elements 300. Of course, the piezoelectric element holding portion 32 is provided integrally over the rows of the plurality of piezoelectric elements 300. You may do it.
[0051]
As such a reservoir forming substrate 30, it is preferable to use a material substantially the same as the coefficient of thermal expansion of the flow path forming substrate 10, for example, glass, a ceramic material, etc. In this embodiment, the flow path forming substrate 10 is used. It was formed using a silicon single crystal substrate of the same material. Thereby, even if it is adhesion | attachment at high temperature using a thermosetting adhesive agent, both can be adhere | attached reliably.
[0052]
A drive circuit 110 such as a semiconductor integrated circuit (IC) for driving each piezoelectric element 300 is mounted on a region corresponding to the piezoelectric element holding portion 32 of the reservoir forming substrate 30. The drive circuit 110 is connected by a connection wiring 120 made of a bonding wire or the like extending through a through portion 33 provided in a region between the piezoelectric element holding portion 32 and the reservoir portion 31 of the reservoir forming substrate 30. The lead electrodes 90 are electrically connected to each other.
[0053]
Here, each piezoelectric element 300 is continuously extended from the inside of the piezoelectric element holding portion 32 of the reservoir forming substrate 30 to a region facing the through portion 33, and the lead electrode 90 is formed in the through portion 33. It is extended.
[0054]
In the present embodiment, the piezoelectric element 300 includes a piezoelectric active part 320 that is provided in a region corresponding to the pressure generation chamber 12 and serves as a substantial driving part, and a piezoelectric layer continuous from the piezoelectric active part 320. The piezoelectric non-active portion 330 is provided at least but not substantially driven, and the piezoelectric non-active portion 330 extends from the inside of the piezoelectric element holding portion 32 to the inside of the through portion 33.
[0055]
In the present embodiment, the piezoelectric inactive portion 330 is a piezoelectric body in a region where the piezoelectric layer 70 and the upper electrode film 80 are continuously extended from the piezoelectric active portion 320 and the reservoir forming substrate 30 is joined. Below the layer 70, a discontinuous lower electrode film 61 made of the same layer as the lower electrode film 60 constituting the piezoelectric active part 320 and discontinuous with the lower electrode film 60 is provided.
[0056]
Further, the region other than the region where the piezoelectric element 300 of the flow path forming substrate 10 is formed, that is, the region where the reservoir forming substrate 30 of the flow path forming substrate 10 is bonded is the same as the upper electrode film 80 of the piezoelectric element 300. The bonding layer 130 is formed of a single layer and has a discontinuous upper electrode film 81 that is discontinuous with the upper electrode film 80.
[0057]
Further, in the present embodiment, the bonding layer 130 constitutes the piezoelectric element 300 and is formed as a discontinuous layer with the piezoelectric element 300. That is, the bonding layer 130 of the present embodiment is composed of the discontinuous lower electrode film 61 and the same layer as the piezoelectric layer 70 of the piezoelectric element 300 and the discontinuous piezoelectric layer 71 discontinuous with the piezoelectric layer 70. The discontinuous upper electrode film 81 is formed at substantially the same height as the piezoelectric element 300.
[0058]
The reservoir forming substrate 30 is bonded to the upper electrode film 80 constituting the piezoelectric inactive portion 330 and the discontinuous upper electrode film 81 of the bonding layer 130 with an adhesive or the like. As described above, the upper electrode film 80 and the discontinuous upper electrode film 81 have substantially the same height, and there is substantially no step on the surface to which the reservoir forming substrate 30 is bonded. Good bonding can be achieved.
[0059]
Further, in the present embodiment, such a bonding layer 130 is also provided independently between the piezoelectric inactive portions 330 (see FIG. 3B). As a result, even in the region where the piezoelectric element 300 is formed, the region where the reservoir forming substrate 30 is bonded is substantially flat and substantially flat.
[0060]
Therefore, the reservoir forming substrate 30 can be more satisfactorily bonded to the flow path forming substrate 10, and the piezoelectric element holding portion 32 can also be reliably sealed. That is, since the piezoelectric element 300 and the bonding layer 130 have substantially the same height, and all the regions where the reservoir forming substrate 30 of the flow path forming substrate 10 is bonded are substantially flat, Can be easily made uniform in the in-plane direction, and both can be bonded well.
[0061]
As a result, it is possible to reliably prevent moisture in the atmosphere from entering the piezoelectric element holding portion 32 and to prevent the piezoelectric element 300 from being damaged due to moisture.
[0062]
Furthermore, in the present embodiment, since the lead electrode 90 is extended in the through portion 33 outside the piezoelectric element holding portion 32, an adhesive for bonding the flow path forming substrate 10 and the reservoir forming substrate 30 together. However, since it does not protrude onto the lead electrode 90, the connection wiring 120 can be satisfactorily connected to the lead electrode 90 by wire bonding.
[0063]
In the present embodiment, the bonding layer 130 is formed of a layer constituting the piezoelectric element 300, but the bonding layer 130 is a discontinuous upper electrode that is discontinuous with the upper electrode film 80 of the piezoelectric element 300 on the uppermost layer. It is only necessary to have the film 81, and other layers may of course be formed of layers other than the layers constituting the piezoelectric element 300.
[0064]
In addition, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded onto the reservoir forming substrate 30. Here, the sealing film 41 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film having a thickness of 6 μm), and the sealing film 41 seals one surface of the reservoir portion 31. It has been stopped. The fixing plate 42 is made of a hard material such as metal (for example, stainless steel (SUS) having a thickness of 30 μm). Since the region of the fixing plate 42 facing the reservoir 100 is an opening 43 that is completely removed in the thickness direction, one surface of the reservoir 100 is sealed only with a flexible sealing film 41. Thus, the flexible portion 34 is deformable by a change in internal pressure.
[0065]
In such an ink jet recording head of this embodiment, after taking ink from an external ink supply means (not shown) and filling the interior from the reservoir 100 to the nozzle opening 21, according to the recording signal from the drive circuit 110, A voltage is applied between each of the lower electrode film 60 and the upper electrode film 80 corresponding to the pressure generation chamber 12 to cause the elastic film 50, the lower electrode film 60, and the piezoelectric layer 70 to bend and deform, thereby generating each pressure. The pressure in the chamber 12 increases and ink droplets are ejected from the nozzle openings 21.
[0066]
The manufacturing method of the ink jet recording head of the present embodiment described above is not particularly limited, but an example thereof will be described with reference to FIGS. 4 to 6 are cross-sectional views showing a part of the pressure generating chamber 12 in the longitudinal direction.
[0067]
First, as shown in FIG. 4A, an elastic film 50 made of silicon dioxide is formed by thermally oxidizing a silicon single crystal substrate wafer to be the flow path forming substrate 10 in a diffusion furnace at about 1100 ° C.
[0068]
Next, as shown in FIG. 4B, after the lower electrode film 60 is formed on the entire surface of the elastic film 50 by sputtering, the lower electrode film 60 is patterned in a region corresponding to the piezoelectric element 300 and the reservoir forming substrate 30. A discontinuous lower electrode film 61 that is discontinuous with the lower electrode film 60 that constitutes the piezoelectric element 300 is formed in a region where the electrodes are joined. As a material of the lower electrode film 60 (discontinuous lower electrode film 61), platinum (Pt) or the like is suitable. This is because a piezoelectric layer 70 described later formed by sputtering or 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. Because. 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, particularly when lead zirconate titanate (PZT) is used as the piezoelectric layer 70. It is desirable that the change in conductivity due to diffusion of lead oxide is small, and platinum is preferable for these reasons.
[0069]
Next, as shown in FIG. 4C, the piezoelectric layer 70 is formed. The piezoelectric layer 70 preferably has crystals oriented. For example, in the present embodiment, a so-called sol-gel method is obtained in which a so-called sol in which a metal organic material is dissolved and dispersed in a catalyst is applied and dried to be gelled, and further baked at a high temperature to obtain a piezoelectric layer 70 made of metal oxide Thus, the piezoelectric layer 70 in which the crystals are oriented is obtained. As a material of the piezoelectric layer 70, a lead zirconate titanate-based material is suitable when used for an ink jet recording head. In addition, the film-forming method of this piezoelectric material layer 70 is not specifically limited, For example, you may form by sputtering method.
[0070]
Furthermore, after forming a lead zirconate titanate precursor film by a sol-gel method or a sputtering method, a method of crystal growth at a low temperature by a high-pressure treatment method in an alkaline aqueous solution may be used.
[0071]
In any case, the piezoelectric layer 70 thus formed has crystals preferentially oriented unlike the bulk piezoelectric body, and in this embodiment, the piezoelectric layer 70 is formed in a columnar shape. Has been. Note that the preferential orientation refers to a state in which the orientation direction of the crystal is not disordered and a specific crystal plane is oriented in a substantially constant direction. A columnar thin film refers to a state in which substantially cylindrical crystals are aggregated over the surface direction with the central axis substantially coincided with the thickness direction to form a thin film. Of course, it may be a thin film formed of preferentially oriented granular crystals. Note that the thickness of the piezoelectric layer manufactured in this way in the thin film process is generally 0.2 to 5 μm.
[0072]
Next, as shown in FIG. 4D, the upper electrode film 80 is formed by sputtering or the like. The upper electrode film 80 is preferably made of a material having high conductivity and good adhesion to the reservoir forming substrate 30 made of a silicon single crystal substrate. For this reason, for example, ruthenium, ruthenium oxide, platinum, iridium, or the like is preferably used as the material of the upper electrode film 80. In this embodiment, ruthenium oxide is used.
[0073]
Next, as shown in FIG. 5A, only the piezoelectric layer 70 and the upper electrode film 80 are etched to form the piezoelectric element 300, and the discontinuous piezoelectric layer 71 and the discontinuous lower electrode film 61 are formed on the discontinuous lower electrode film 61. The discontinuous upper electrode film 81 is patterned to form the bonding layer 130.
[0074]
Next, as shown in FIG. 5B, lead electrodes 90 are formed. Specifically, for example, a lead electrode 90 made of gold (Au) or the like is formed over the entire surface of the flow path forming substrate 10 and patterned for each piezoelectric element 300.
[0075]
The above is the film forming process. After forming the film in this manner, the above-described anisotropic etching of the silicon single crystal substrate with the alkaline solution is performed, and as shown in FIG. 5C, the pressure generating chamber 12, the communication portion 13, and the ink supply path 14 etc. are formed.
[0076]
Thereafter, as shown in FIG. 6A, the reservoir forming substrate 30 is bonded to the bonding layer 130 and the piezoelectric element 300 (piezoelectric inactive portion 330) provided on the flow path forming substrate 10 by an adhesive.
[0077]
In this manner, the reservoir forming substrate 30 and the piezoelectric element 300 are bonded to each other, that is, by bonding to the upper electrode film 80 and the discontinuous upper electrode film 81, the reservoir forming substrate 30 and the flow path are formed. The substrate 10 can be bonded well. In particular, in the present embodiment, since the height of the piezoelectric element 300 and the bonding layer 130 is substantially the same, the surface to which the reservoir forming substrate 30 is bonded becomes substantially flat, and the reservoir forming substrate 30 is bonded more satisfactorily. can do.
[0078]
After that, as shown in FIG. 6B, the nozzle plate 20 having the nozzle openings 21 formed on the surface of the flow path forming substrate 10 opposite to the reservoir forming substrate 30 is joined and the reservoir is formed. The compliance substrate 40 is bonded onto the substrate 30. Although not shown, the drive circuit 110 is mounted on the reservoir forming substrate 30, and the connection wiring 120 that connects the drive circuit 110 and the lead electrode 90 is formed by wire bonding, so that the ink jet recording according to the present embodiment is performed. The head is used (see FIG. 2B).
[0079]
As described above, since the lead electrode 90 is formed in the through portion 33 outside the piezoelectric element holding portion 32, the adhesive for bonding the flow path forming substrate 10 and the reservoir forming substrate 30 is the lead electrode 90. It doesn't protrude to the top. Therefore, the bonding strength between the connection wiring 120 and the lead electrode 90 is improved, and an ink jet recording head with improved durability and reliability can be realized.
[0080]
In practice, a large number of chips are simultaneously formed on a single wafer by the above-described series of film formation and anisotropic etching, and after the process is completed, a single chip-sized flow path is formed as shown in FIG. Divide each substrate 10. Then, the reservoir forming substrate 30 and the compliance substrate 40 are sequentially bonded and integrated with the divided flow path forming substrate 10 to form an ink jet recording head.
[0081]
(Other embodiments)
Although one embodiment of the present invention has been described above, the basic configuration of the ink jet recording head is not limited to that described above.
[0082]
For example, in the above-described embodiment, the thin film type ink jet recording head manufactured by applying the film forming and lithography processes is taken as an example. However, the present invention is not limited to this. For example, a green sheet is pasted. The present invention can also be applied to a thick film type ink jet recording head formed by such a method.
[0083]
In addition, the ink jet recording heads of these embodiments constitute a part of a recording head unit having an ink flow path communicating with an ink cartridge or the like, and are mounted on the ink jet recording apparatus. FIG. 7 is a schematic view showing an example of the ink jet recording apparatus.
[0084]
As shown in FIG. 7, in the recording head units 1A and 1B having the ink jet recording head, cartridges 2A and 2B constituting ink supply means are detachably provided, 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 body 4 so as to be movable in the axial direction. The recording head units 1A and 1B, for example, are configured to eject a black ink composition and a color ink composition, respectively.
[0085]
The driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted is moved along the carriage shaft 5. The On the other hand, the apparatus 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 conveyed on the platen 8. It is like that.
[0086]
【The invention's effect】
As described above, in the present invention, since the sealing substrate is bonded to the upper electrode film constituting the upper electrode of the piezoelectric element, the bonding strength between the sealing substrate and the flow path forming substrate is improved and the sealing is performed. The part can be reliably sealed. Therefore, moisture in the atmosphere does not enter the sealing portion, and destruction of the piezoelectric element due to moisture in the atmosphere can be reliably prevented.
[Brief description of the drawings]
FIG. 1 is a perspective view schematically showing an ink jet recording head according to a first embodiment of the invention.
2A and 2B are a plan view and a cross-sectional view illustrating the ink jet recording head according to the first embodiment of the invention.
FIG. 3 is a cross-sectional view illustrating the ink jet recording head according to the first embodiment of the invention.
FIG. 4 is a cross-sectional view showing a manufacturing process of the ink jet recording head according to the first embodiment of the invention.
FIG. 5 is a cross-sectional view showing a manufacturing process of the ink jet recording head according to the first embodiment of the invention.
FIG. 6 is a cross-sectional view illustrating a manufacturing process of the ink jet recording head according to the first embodiment of the invention.
FIG. 7 is a schematic view of an ink jet recording apparatus according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Flow path formation board | substrate 12 Pressure generation chamber 20 Nozzle plate 21 Nozzle opening 30 Reservoir formation board 31 Reservoir part 32 Piezoelectric element holding part 40 Compliance board | substrate 60 Lower electrode film 61 Discontinuous lower electrode film 70 Piezoelectric layer 71 Discontinuous piezoelectric body layer 80 Upper electrode film 81 Discontinuous upper electrode film 100 Reservoir 110 Drive circuit 120 Connection wiring 130 Bonding layer 300 Piezoelectric element 320 Piezoelectric active part 330 Piezoelectric inactive part

Claims (6)

A flow path forming substrate in which a pressure generation chamber communicating with a nozzle opening for ejecting ink is defined, and a lower electrode, a piezoelectric layer, and an upper electrode provided on one side of the flow path forming substrate via a vibration plate In an inkjet recording head comprising the piezoelectric element,
The surface on the piezoelectric element side of the flow path forming substrate has a sealing portion for sealing the space in a state where a space is secured in a region facing the piezoelectric element, and at least one of the common ink chambers of the pressure generation chambers. Comprising a reservoir forming substrate having a reservoir portion constituting a portion, wherein the piezoelectric element is continuously extended to the outside of the sealing portion,
The region where the reservoir forming substrate of the flow path forming substrate is joined is a layer constituting the piezoelectric element, and is a layer discontinuous from the piezoelectric element, and is discontinuous from the upper electrode in the uppermost layer. A discontinuous upper electrode film is provided with a bonding layer having the same height as the piezoelectric element ,
The reservoir forming substrate is joined to an upper electrode film constituting the upper electrode constituting the piezoelectric element including the discontinuous upper electrode film constituting the joining layer but not being substantially driven. Inkjet recording head.   The piezoelectric element has a piezoelectric active part that is a substantial driving part, and a piezoelectric non-active part that has at least a piezoelectric layer continuous from the piezoelectric active part but is not substantially driven, and this piezoelectric body 2. The ink jet recording head according to claim 1, wherein an inactive portion extends from the inside of the sealing portion to the outside of the sealing portion.   The region where the reservoir forming substrate of the piezoelectric inactive part is joined is composed of a lower electrode film constituting the lower electrode of the piezoelectric active part, and a discontinuous lower electrode film that is discontinuous with the lower electrode. The ink jet recording head according to claim 2, wherein the ink jet recording head is provided.   4. The ink jet type according to claim 1, wherein a lead electrode having one end connected to an external wiring is electrically connected to the piezoelectric element outside the sealing portion. 5. Recording head.   The ink jet recording head according to claim 1, wherein the bonding layer is provided independently between the piezoelectric elements.   An ink jet recording apparatus comprising the ink jet recording head according to claim 1.

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