JP3786178B2 - Inkjet recording head, method for manufacturing the same, and inkjet recording apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is an inkjet in which 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 provided through the diaphragm, and ink droplets are ejected by displacement of the piezoelectric element. The present invention relates to a recording head, a manufacturing method thereof, 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]
[Problems to be solved by the invention]
However, in the above-described ink jet recording head, the pressure generating chambers are formed so as to penetrate the flow path forming substrate. Therefore, when the arrangement density of the pressure generating chambers is increased, the thickness of the partition walls defining the pressure generating chambers is reduced. There is a problem that crosstalk occurs between adjacent pressure generation chambers.
[0007]
In order to solve such a problem, it is desirable to reduce the thickness of the flow path forming substrate, but there is a problem that the rigidity of the flow path forming substrate itself is reduced and cracks and the like are derived in the manufacturing process.
[0008]
Further, in such an ink jet recording head, a nozzle plate having a plurality of nozzle openings for ejecting ink droplets is used, and a flow path is provided so that the nozzle plate communicates with the nozzle opening and the pressure generating chamber. It is bonded to the formation substrate with an adhesive or the like. For this reason, when the pressure generating chambers are arranged at a high density, the adhesive area between the nozzle plate and the flow path forming substrate becomes small, so that the adhesive may flow excessively into the pressure generating chambers, resulting in characteristic deterioration.
[0009]
In view of such circumstances, the present invention provides an ink jet recording head that can reduce the thickness of a flow path forming substrate, prevent breakage, and maintain good ink discharge characteristics, a manufacturing method thereof, and an ink jet recording apparatus. The task is to do.
[0010]
[Means for Solving the Problems]
According to a first aspect of the present invention for solving the above problems, a nozzle plate having a nozzle opening, a flow path forming substrate in which a pressure generating chamber communicating with the nozzle opening is defined, and the flow path forming substrate. In the ink jet recording head comprising a lower electrode provided in a region corresponding to the pressure generating chamber via a vibration plate, a piezoelectric element composed of a piezoelectric layer and an upper electrode, the nozzle plate and the flow path forming substrate Are made of single crystal silicon, and these are bonded via a silicon oxide film without using an adhesive.
[0011]
In the first aspect, the flow path forming substrate and the nozzle plate are well bonded by the silicon oxide film to form an integral structure, and the rigidity of the flow path forming substrate is improved and the ink ejection characteristics are well maintained.
[0012]
According to a second aspect of the present invention, there is provided the ink jet recording head according to the first aspect, wherein the silicon oxide film is continuously formed on an inner surface of the pressure generating chamber and the nozzle opening.
[0013]
In the second aspect, as a result of joining the flow path forming substrate and the nozzle plate with the silicon oxide film formed by thermal oxidation, the silicon oxide film is formed on the inner surfaces of the pressure generating chamber and the nozzle opening.
[0014]
According to a third aspect of the present invention, in the first or second aspect, the silicon oxide film includes a plurality of protrusions projecting from one joint surface of the flow path forming substrate or the nozzle plate to the other joint surface. The protrusion is embedded in an ink jet recording head.
[0015]
In the third aspect, as a result of joining the flow path forming substrate and the nozzle plate with the silicon oxide film with the protrusion interposed therebetween, the protrusion is embedded in the silicon oxide film.
[0016]
According to a fourth aspect of the present invention, in any one of the first to third aspects, the pressure generating chamber is formed on a silicon single crystal substrate by anisotropic etching, and each layer constituting the piezoelectric element is formed and lithographically formed. The ink jet recording head is formed by a method.
[0017]
In the fourth aspect, the pressure generation chamber can be formed with high accuracy and high density relatively easily.
[0018]
A fifth 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 fourth aspects.
[0019]
In the fifth aspect, it is possible to realize an ink jet recording apparatus that always has good ink ejection characteristics and improved reliability.
[0020]
According to a sixth aspect of the present invention, there is provided a nozzle plate made of single crystal silicon and having a nozzle opening, a flow path forming substrate made of single crystal silicon and having a pressure generation chamber communicating with the nozzle opening, In a manufacturing method of an ink jet recording head comprising a piezoelectric element formed in a region corresponding to the pressure generation chamber via a vibration plate constituting a part of the pressure generation chamber, on one surface of the flow path forming substrate A first step of forming an elastic film constituting at least a part of the diaphragm; a second step of forming the pressure generating chamber by etching from the other surface side of the flow path forming substrate; and the flow In a state where the opening surface side of the path forming substrate and the nozzle plate are spaced apart from each other by a predetermined distance, the flow path forming substrate and the nozzle plate are thermally oxidized to join both with a silicon oxide film. And extent, in the manufacturing method of the ink jet recording head characterized in that it comprises a fourth step of forming the piezoelectric element.
[0021]
In the sixth aspect, the flow path forming substrate and the nozzle plate can be easily and satisfactorily joined with the silicon oxide film.
[0022]
According to a seventh aspect of the present invention, in the sixth aspect, the third step includes a plurality of protrusions projecting at a certain height on at least one of the joining surfaces of the flow path forming substrate and the nozzle plate. Including a step of forming a protrusion, and the protrusion is brought into contact with the other bonding surface so that a space is secured between the flow path forming substrate and the nozzle plate, and both are thermally oxidized and bonded together. The present invention is directed to a method for manufacturing an ink jet recording head.
[0023]
In the seventh aspect, both are bonded by the silicon oxide film formed on each bonding surface of the flow path forming substrate and the nozzle plate.
[0024]
According to an eighth aspect of the present invention, in the sixth aspect, in the third step, the silicon oxide film integrally formed on the surface of either the flow path forming substrate or the nozzle plate is the other step. An ink jet recording head manufacturing method is characterized in that both are bonded by thermal oxidation in a state where the bonding surfaces are in contact with each other.
[0025]
In the eighth aspect, a silicon oxide film is formed on the other bonding surface, and both are bonded.
[0026]
According to a ninth aspect of the present invention, in the eighth aspect, in the second step, the flow path forming substrate is etched using the silicon oxide film formed on the surface of the flow path forming substrate as a mask. In the third step, there is provided an ink jet recording head manufacturing method, wherein the nozzle plate is thermally oxidized in a state where the bonding surface of the nozzle plate is in contact with a silicon oxide film used as a mask to bond the two.
[0027]
In the ninth aspect, since the flow path forming substrate and the nozzle plate are bonded using the silicon oxide film used as a mask for forming the pressure generating chamber, the manufacturing process is simplified.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments.
[0029]
(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 and a cross-sectional view of FIG.
[0030]
As shown in the figure, the flow path forming substrate 10 is composed of a silicon single crystal substrate having a plane orientation (110) in the present embodiment, and the flow path forming substrate 10 is anisotropically etched from one surface thereof. Pressure generating chambers 12 partitioned by a plurality of partition walls 11 are arranged side by side in the width direction. Further, a communication portion 13 serving as a relay chamber between the reservoirs of the reservoir forming substrate, which will be described later, is formed outside the pressure generation chamber 12 in the longitudinal direction. 14 to communicate with each other.
[0031]
Further, on the other surface of the flow path forming substrate 10, for example, a first elastic film 50 made of a silicon oxide film (SiO ₂ ) and a second elastic film made of, for example, zirconium oxide (ZrO ₂ ) or the like. 51 is formed.
[0032]
Here, in the anisotropic etching, when the 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) The second (111) plane that forms an angle of about 70 degrees with the (110) plane and the angle of about 35 degrees with the (110) plane appears, and is compared with the etching rate of the (110) plane (111) This is performed by utilizing the property that the etching rate of the surface 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.
[0033]
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 first elastic film 50. Here, the amount of the first elastic film 50 eroded 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.
[0034]
Note that the thickness of the flow path forming substrate 10 is selected in accordance with the density at which the pressure generating chambers 12 are disposed. For example, when the pressure generating chamber 12 is arranged so as to obtain a resolution of about 180 dpi, the thickness of the flow path forming substrate 10 is preferably about 180 to 280 μm, more preferably about 220 μm. For example, when the pressure generating chamber 12 is arranged so as to obtain a resolution of about 360 dpi, the thickness of the flow path forming substrate 10 is preferably set to 100 μm or less. This is because the arrangement density can be increased while maintaining the rigidity of the partition between adjacent pressure generating chambers.
[0035]
Further, a nozzle plate 20 in which a nozzle opening 21 communicating with the opposite side to the ink supply path 14 of each pressure generating chamber 12 is bonded to the other surface side of the flow path forming substrate 10 is joined by an adhesive. . The nozzle plate 20 is made of a silicon single crystal substrate, and the nozzle openings 21 are formed by dry etching the silicon single crystal substrate. In the present embodiment, the nozzle opening 21 includes a nozzle portion 21a that ejects ink droplets, and a nozzle communication portion 21b that is formed with a larger diameter than the nozzle portion 21a and communicates the nozzle portion 21a and the pressure generation chamber 12. Consists of.
[0036]
Here, the size of the nozzle portion 21a of the nozzle opening 21 and the size of the pressure generating chamber 12 are optimized according to the amount of ink droplets to be ejected, the ejection speed, the ejection frequency, and the like. For example, when 360 ink droplets are recorded per inch, the nozzle portion 21a needs to be accurately formed with a diameter of several tens of μm.
[0037]
Here, the nozzle plate 20 and the flow path forming substrate 10 are bonded via the silicon oxide film 100 in the present embodiment. That is, the nozzle plate 20 and the flow path forming substrate 10 are integrated with the silicon oxide film 100 instead of being bonded using an adhesive. Further, in the present embodiment, a protrusion 55 protruding from the bonding surface of the flow path forming substrate 10 to the bonding surface of the nozzle plate is embedded in the silicon oxide film. A method for joining the flow path forming substrate 10 and the nozzle plate 20 will be described in detail later.
[0038]
Further, the silicon oxide film 100 is continuously formed on the inner surface of each pressure generating chamber 12 formed on the flow path forming substrate 10, the inner surface of the nozzle opening 21 formed in the nozzle plate 20, and the surface of the nozzle plate 20. Has been.
[0039]
On the other hand, on the second elastic film 51 provided on the flow path forming substrate 10, a lower electrode film 60 having a thickness of, for example, about 0.2 μm and a thickness of, for example, about 0.5 to 3 μm. The piezoelectric layer 70 and the 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.
[0040]
The upper electrode film 80 that is an individual electrode of each piezoelectric element 300 is connected to an external wiring (not shown) via a lead electrode 90 that extends from the longitudinal end of the piezoelectric element 300 on the peripheral wall.
[0041]
Here, a method of manufacturing such an ink jet recording head will be described with reference to FIGS. 3 and 4 are cross-sectional views of the pressure generation chamber 12 in the width direction.
[0042]
First, as shown in FIG. 3A, the first elastic film 50 is formed on one surface of the flow path forming substrate 10, and the protective film 52 is formed on the other surface. That is, the first elastic film 50 and the protective film 52 made of silicon oxide are respectively formed on the surface of the flow path forming substrate 10 by thermally oxidizing the silicon single crystal substrate to be the flow path forming substrate 10 in a diffusion furnace at about 1100 ° C. Is formed.
[0043]
Next, as shown in FIG. 3B, after forming a zirconium layer on the first elastic film 50, for example, a second elastic film made of zirconium oxide is thermally oxidized in a diffusion furnace at 500 to 1200 ° C. 51 is formed.
[0044]
Next, as shown in FIG. 3C, the protective film 52 is patterned to form an opening 52a in a region where the pressure generating chamber 12, the communication portion 13, and the ink supply path 14 are formed. The flow path forming substrate 10 is etched through the part 52 a to form the pressure generation chamber 12, the communication part 13, and the ink supply path 14.
[0045]
Next, as shown in FIG. 4A, the protective film 52 is further patterned to form a plurality of protrusions 55 on the surface of the flow path forming substrate 10. These protrusions 55 are for holding a space between the flow path forming substrate 10 and the nozzle plate 20 in a process to be described later. Is not particularly limited, but preferably has substantially the same height. Further, the number and positions of the projections 55 are not particularly limited, but it is preferable to provide the projections 55 on the entire surface of the flow path forming substrate 10 at substantially constant intervals.
[0046]
Next, as shown in FIG. 4B, the two are joined by thermally oxidizing the flow path forming substrate 10 and the nozzle plate 20 with a predetermined gap therebetween. Specifically, the protrusion 55 formed on the surface of the flow path forming substrate 10 is brought into contact with the surface of the nozzle plate 20, and a space is secured between the flow path forming substrate 10 and the nozzle plate 20, The flow path forming substrate 10 and the nozzle plate 20 are thermally oxidized by heating to about 1100 ° C. As a result, the silicon oxide film 100 is formed on the respective surfaces of the flow path forming substrate 10 and the nozzle plate 20, and the silicon oxide film 100 is integrated to join the two. That is, the flow path forming substrate 10 and the nozzle plate 20 have an integral structure.
[0047]
At this time, the silicon oxide film 100 is continuously formed on the inner surface of the pressure generating chamber 12, the inner surface of the nozzle opening 21, and the surface of the nozzle plate 20 at the same time.
[0048]
Here, in this embodiment, since the protrusions 55 are formed on the entire surface of the flow path forming substrate 10 at substantially constant intervals, the flow of the protrusions 55 by bringing them into contact with the surface of the nozzle plate 20. A space is defined between the path forming substrate 10 and the nozzle plate 20 with a substantially uniform width. Therefore, by thermally oxidizing the flow path forming substrate 10 and the nozzle plate 20, the silicon oxide film 100 is uniformly formed, and the flow path forming substrate 10 and the nozzle plate 20 are favorably bonded.
[0049]
In the present embodiment, since the flow path forming substrate 10 and the nozzle plate 20 are joined by the silicon oxide film 100 without using an adhesive, the adhesive does not flow into the pressure generating chamber 12 or the like. It is possible to prevent deterioration of characteristics due to nozzle clogging and vibration plate restraint.
[0050]
Further, since no adhesive is used, for example, it is possible to cope with a high temperature process such as firing of the piezoelectric layer 70 described later. Therefore, the flow path forming substrate 10 and the nozzle plate 20 can be joined before the piezoelectric element 300 is formed. Thereby, since the rigidity of the flow path forming substrate 10 is improved, it is possible to prevent the flow path forming substrate 10 from being cracked during the manufacturing process. Further, even when the flow path forming substrate 10 having a relatively thin thickness is used, the rigidity is improved by joining the nozzle plate 20, so that the generation of cracks and the like can be prevented and the handling becomes easy.
[0051]
Furthermore, since the silicon oxide film 100 is continuously formed on the inner surface of the pressure generating chamber 12 and the like when the flow path forming substrate 10 and the nozzle plate 20 are joined, Hydrophilicity is improved and ink ejection characteristics are improved.
[0052]
In addition, since the nozzle plate 20 is formed of the same material as the flow path forming substrate 10, warpage and reaction may occur in a heat process at the time of bonding to the flow path forming substrate 10 and a heat process in a subsequent process at the time of mounting. In other words, the flow path forming substrate 10 or the nozzle plate 20 is not cracked.
[0053]
In the present embodiment, the plurality of protrusions 55 are provided on the joint surface of the flow path forming substrate 10. However, the present invention is not limited to this, and may of course be provided on the joint surface of the nozzle plate 20. .
[0054]
In the present embodiment, the silicon oxide films formed on the surfaces of the flow path forming substrate 10 and the nozzle plate 20 are thermally oxidized in a state in which a predetermined space is held by the protrusions 55 and the both are thermally oxidized. Although both are joined by 100, the joining method of these flow path formation board | substrates 10 and the nozzle plate 20 is not limited to this. For example, the nozzle plate 20 is in contact with the protective film 52 made of silicon oxide formed on the flow path forming substrate 10, that is, between the flow path forming substrate 10 and the nozzle plate 20 via the protective film 55. Both can be satisfactorily bonded by heating to about 1600 ° C. with a predetermined interval. Needless to say, a silicon oxide film may be separately provided on the surface of the nozzle plate 20.
[0055]
In addition, after joining the flow path forming substrate 10 and the nozzle plate 20 in this way, piezoelectric elements corresponding to the pressure generating chambers 12 are provided on the side opposite to the joint surface of the flow path forming substrate 10 with the nozzle plate 20. Element 300 is formed.
[0056]
Specifically, first, as shown in FIG. 4C, after forming the lower electrode film 60 on the entire surface of the second elastic film 51 by sputtering, the lower electrode film 60 is patterned to form the entire pattern. As a material of the lower electrode film 60, 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.
[0057]
Next, as shown in FIG. 5A, a piezoelectric layer 70 is formed. The piezoelectric layer 70 preferably has crystals oriented. For example, in this 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, dried, gelled, and fired at a high temperature to obtain a piezoelectric layer 70 made of a 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.
[0058]
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.
[0059]
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.
[0060]
Next, as shown in FIG. 5B, an upper electrode film 80 is formed. The upper electrode film 80 only needs to be a highly conductive material, and many metals such as aluminum, gold, nickel, and platinum, conductive oxides, and the like can be used. In this embodiment, the platinum film is formed by sputtering.
[0061]
Next, as shown in FIG. 5C, the piezoelectric element 300 is patterned by etching only the piezoelectric layer 70 and the upper electrode film 80.
[0062]
After that, for example, a metal layer made of gold (Au) or the like is formed over the entire surface of the flow path forming substrate 10, and the lead electrode 90 is formed by patterning for each piezoelectric element 300.
[0063]
In practice, a large number of chips are simultaneously formed on a single wafer by such a series of film formation and anisotropic etching, and after the completion of the process, the flow of one chip size as shown in FIG. Divide each path forming substrate 10. Then, a reservoir forming substrate 30 and a compliance substrate 40 (to be described later) are sequentially bonded and integrated with the divided flow path forming substrate 10 to form an ink jet recording head.
[0064]
That is, as shown in FIGS. 1 and 2, a reservoir forming substrate 30 having a reservoir 31 is joined to the piezoelectric element 300 side of the flow path forming substrate 10 in which the pressure generating chambers 12 and the like are formed. In this embodiment, the reservoir 31 is formed across the reservoir forming substrate 30 in the thickness direction and across the width direction of the pressure generating chamber 12. The reservoir portion 31 is in communication with the communication portion 13 of the flow path forming substrate 10 through a through hole 57 provided through the first and second elastic films 50 and 51 and the lower electrode film 60. .
[0065]
In addition, in a region facing the piezoelectric element 300 of the reservoir forming substrate 30, a piezoelectric element holding portion 33 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. . At least the piezoelectric active part 320 of the piezoelectric element 300 is sealed in the piezoelectric element holding part 33 to prevent the piezoelectric element 300 from being destroyed due to an external environment such as moisture in the atmosphere.
[0066]
As the reservoir forming substrate 30, for example, it is preferable to use a material substantially the same as the coefficient of thermal expansion of the flow path forming substrate 10 such as glass or ceramic material. In this embodiment, the same material as the flow path forming substrate 10 is used. It was formed using a silicon single crystal substrate. Thereby, like the case of the above-mentioned nozzle plate 20, even if it is the adhesion | attachment at high temperature using a thermosetting adhesive agent, both can be adhere | attached reliably. Therefore, the manufacturing process can be simplified.
[0067]
Further, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded to 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 unit 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 31 is an opening 43 that is completely removed in the thickness direction, one surface of the reservoir 31 is sealed only with a flexible sealing film 41. Thus, the flexible portion 32 is deformable by a change in internal pressure.
[0068]
An ink introduction port 35 for supplying ink to the reservoir 31 is formed on the compliance substrate 40 on the outer side of the central portion in the longitudinal direction of the reservoir 31. Further, the reservoir forming substrate 30 is provided with an ink introduction path 36 that allows the ink introduction port 35 and the side wall of the reservoir 31 to communicate with each other.
[0069]
The ink jet recording head configured in this manner takes in ink from an ink introduction port 35 connected to an external ink supply means (not shown), fills the interior from the reservoir 31 to the nozzle opening 21, and then fills the inside with an external (not shown). In accordance with a recording signal from the drive circuit, a voltage is applied between the upper electrode film 80 and the lower electrode film 60, and the first and second elastic films 50 and 52, the lower electrode film 60, and the piezoelectric layer 70 are bent and deformed. By doing so, the pressure in the pressure generating chamber 12 increases, and ink droplets are ejected from the nozzle openings 21.
[0070]
(Other embodiments)
While the embodiments of the present invention have been described above, the basic configuration of the ink jet recording head is not limited to that described above.
[0071]
For example, in the above-described embodiment, the first and second elastic films 50 and 51 are provided on the flow path forming substrate 10. However, the present invention is not limited to this, for example, the first elastic film 50 or the first elastic film 50 or 51. Only one of the two elastic films 51 may be provided.
[0072]
In addition, for example, the above-described embodiment has exemplified a thin film type ink jet recording head that can be manufactured by applying a film forming and lithography process. However, the present invention is not limited to this example. Various types of structures, such as those that form pressure generation chambers, those that form a piezoelectric layer by attaching a green sheet or screen printing, or those that form a piezoelectric layer by crystal growth such as a hydrothermal method. The present invention can be applied to an ink jet recording head.
[0073]
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.
[0074]
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. 6 is a schematic view showing an example of the ink jet recording apparatus.
[0075]
As shown in FIG. 6, 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.
[0076]
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 3. The platen 8 can be rotated by a driving force of a paper feed motor (not shown), and a recording sheet S that is a recording medium such as paper fed by a paper feed roller is wound around the platen 8 and conveyed. It has become so.
[0077]
【The invention's effect】
As described above, in the present invention, since the flow path forming substrate and the nozzle plate are bonded via the silicon oxide film without using the adhesive, the piezoelectric element that requires a high temperature process in the manufacturing process. Before the forming step, the flow path forming substrate and the nozzle plate can be joined to form an integral structure. Thereby, even when a relatively thin channel forming substrate is used, the rigidity of the channel forming substrate is maintained, and damage in the manufacturing process can be prevented. In addition, since the rigidity of the partition wall is improved by using a relatively thin channel forming substrate, crosstalk can be prevented even if the pressure generating chambers are arranged at a relatively high density.
[0078]
Furthermore, since no adhesive is used to join the flow path forming substrate and the nozzle plate, there is no deterioration in characteristics due to the adhesive flowing into the pressure generating chamber or the like, and an ink jet recording head with improved reliability is realized. Can do.
[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 invention.
FIG. 2 is a diagram illustrating the ink jet recording head according to the first embodiment of the invention, and is a cross-sectional view of FIG.
FIG. 3 is a cross-sectional view showing a manufacturing process of 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 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 11 Partition 12 Pressure generation chamber 20 Nozzle plate 21 Nozzle opening 50 1st elastic film 51 2nd elastic film 60 Lower electrode film 70 Piezoelectric layer 80 Upper electrode film 90 Lead electrode 100 Silicon oxide film 300 Piezoelectric element

Claims (7)

A nozzle plate having a nozzle opening, a flow path forming substrate in which a pressure generating chamber communicating with the nozzle opening is defined, and a region corresponding to the pressure generating chamber of the flow path forming substrate via a vibration plate Ink jet recording head comprising a lower electrode, a piezoelectric layer and a piezoelectric element comprising an upper electrode,
The nozzle plate and the flow path forming substrate are made of single crystal silicon, and these are bonded via a silicon oxide film without using an adhesive, and the silicon oxide film includes the flow path forming substrate or the An ink jet recording head, wherein a plurality of protrusions protruding from any one of the joint surfaces of the nozzle plate to the other joint surface are embedded.   2. The ink jet recording head according to claim 1, wherein the silicon oxide film is continuously formed on inner surfaces of the pressure generating chamber and the nozzle opening.   3. The ink jet type according to claim 1, wherein the pressure generating chamber is formed on a silicon single crystal substrate by anisotropic etching, and each layer constituting the piezoelectric element is formed by film formation and lithography. Recording head.   An ink jet recording apparatus comprising the ink jet recording head according to claim 1. A nozzle plate made of single crystal silicon and having a nozzle opening formed therein, a flow path forming substrate made of single crystal silicon and having a pressure generation chamber communicating with the nozzle opening, and a part of the pressure generation chamber are configured. In a method for manufacturing an ink jet recording head comprising a piezoelectric element formed in a region corresponding to the pressure generating chamber via a vibration plate,
A first step of forming an elastic film constituting at least a part of the vibration plate on one surface of the flow path forming substrate, and the pressure generating chamber is formed by etching from the other surface side of the flow path forming substrate. A second step of performing thermal oxidation of the flow path forming substrate and the nozzle plate with a predetermined gap between the opening surface side of the flow path forming substrate and the nozzle plate to form a silicon oxide film And a fourth step of forming the piezoelectric element, and the third step is performed on at least one of the bonding surfaces of the flow path forming substrate and the nozzle plate. Including a step of forming a plurality of protrusions protruding at a constant height, and a space is secured between the flow path forming substrate and the nozzle plate by bringing the protrusions into contact with the other joint surface. Heat both in state Method for manufacturing an ink jet recording head, which comprises turned into and joined.   6. The method according to claim 5, wherein in the third step, heat is applied in a state where the other bonding surface is in contact with a silicon oxide film integrally formed on one surface of either the flow path forming substrate or the nozzle plate. A method of manufacturing an ink jet recording head, which comprises oxidizing and bonding the two.   7. The method according to claim 6, wherein in the second step, the flow path forming substrate is etched using a silicon oxide film formed on the surface of the flow path forming substrate as a mask. In the third step, the nozzle plate is etched. A method of manufacturing an ink jet recording head, characterized in that a thermal oxidation is performed in a state where a bonding surface is in contact with a silicon oxide film used as a mask to bond the two together.

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