JP2002225268A - Ink-jet recording head, its manufacturing method, and ink-jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet recording head in which an ink discharge characteristic is improved, its manufacturing method, and an ink-jet recorder. SOLUTION: The ink-jet recording head is equipped with a fluid passage forming substrate 10 consisting of a silicon single crystal substrate in which a pressure generation chamber 12 communicating with a nozzle opening 21 is partitioned, a lower substrate 60 set through a diaphragm 50 on one face side of the fluid passage forming substrate 10, and a piezoelectric element 300 comprising a piezoelectric layer 70 and an upper electrode 80. At least at an angle part of an inside face of the pressure generation chamber 12, a protection layer 110 is set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure generating chamber which communicates with a nozzle opening for discharging ink droplets, which is constituted by a vibrating plate. TECHNICAL FIELD The present invention relates to an ink-jet recording head for ejecting ink droplets by a method, a method for manufacturing the same, and an ink-jet recording apparatus.

[0002]

2. Description of the Related Art A part of a pressure generating chamber communicating with a nozzle opening for discharging ink droplets is constituted by a vibrating plate, and the vibrating plate is deformed by a piezoelectric element to pressurize the ink in the pressure generating chamber and to form an ink through the nozzle opening. Ink jet recording heads that eject droplets use a longitudinal vibration mode piezoelectric actuator in which piezoelectric elements expand and contract in the axial direction, and a flexural vibration mode piezoelectric actuator.
The types have been put to practical use.

In the former method, the volume of the pressure generating chamber can be changed by bringing the end face of the piezoelectric element into contact with the diaphragm, so that a head suitable for high-density printing can be manufactured. There is a problem in that a difficult process of cutting into a comb shape in accordance with the arrangement pitch of the openings and an operation of positioning and fixing the cut piezoelectric element in the pressure generating chamber are required, and the manufacturing process is complicated.

On the other hand, in the latter, a piezoelectric element can be formed on a diaphragm by a relatively simple process of sticking a green sheet of a piezoelectric material according to the shape of a pressure generating chamber and firing the green sheet. In addition, there is a problem that a certain area is required due to the use of flexural vibration, and that high-density arrangement is difficult.

On the other hand, in order to solve the latter disadvantage of the recording head, a uniform piezoelectric material layer is formed by a film forming technique over the entire surface of the diaphragm as disclosed in Japanese Patent Application Laid-Open No. 5-286131. A proposal has been made in which the piezoelectric material layer is cut into a shape corresponding to the pressure generating chambers by a lithography method, and a piezoelectric element is formed so as to be independent for each pressure generating chamber.

This eliminates the need for attaching the piezoelectric element to the vibration plate, which not only allows the piezoelectric element to be manufactured by a precise and simple method such as lithography, but also reduces the thickness of the piezoelectric element. There is an advantage that it can be made thin and can be driven at high speed.

In such an ink jet recording head, the flow path forming substrate on which the piezoelectric element is formed and the nozzle plate having the nozzle openings are bonded via an adhesive.

The bonding of the nozzle plate with the adhesive is performed, for example, by transferring and applying an adhesive to the opening surface of the flow path forming substrate where the pressure generating chamber is opened, and pressing the nozzle plate against the flow path forming substrate at a predetermined pressure. This is performed by curing the adhesive in a state where the adhesive is pressed.

[0009]

However, the higher the density of the nozzle openings, that is, the higher the density of the pressure generating chamber, the thinner the partition walls defining the pressure generating chamber and the lower the rigidity. For this reason, when the nozzle plate is pressure-bonded, the partition walls are deformed in the direction in which the pressure generating chambers are juxtaposed, and the width of the pressure generating chambers becomes non-uniform.

In view of such circumstances, an object of the present invention is to provide an ink jet recording head having improved ink ejection characteristics, a method of manufacturing the same, and an ink jet recording apparatus.

[0011]

According to a first aspect of the present invention, there is provided a flow path forming substrate comprising a silicon single crystal substrate in which a pressure generating chamber communicating with a nozzle opening is defined. In an ink jet recording head including a lower electrode, a piezoelectric layer, and a piezoelectric element including an upper electrode via a vibration plate on one surface side of a path forming substrate, a protective layer is provided on at least a corner of the inner surface of the pressure generating chamber. An ink jet recording head comprising:

According to the first aspect, it is possible to prevent the deformation of the partition walls and improve the ink ejection characteristics.

A second aspect of the present invention is the ink jet recording head according to the first aspect, wherein the protective layer is provided over the entire inner surface of the pressure generating chamber.

According to the second aspect, it is possible to prevent the deformation of the partition wall and improve the ink ejection characteristics.

According to a third aspect of the present invention, there is provided an ink jet recording head according to the first or second aspect, wherein the protective layer is formed of a metal having a melting point of 600 to 700 ° C.

In the third aspect, the protection layer is melt-formed at a predetermined temperature, so that the breakage of the piezoelectric layer can be reliably prevented. Further, the bonding substrate can be bonded to the flow path forming substrate by anodic bonding.

According to a fourth aspect of the present invention, there is provided an ink jet recording head according to the third aspect, wherein the metal is selected from the group consisting of aluminum, antimony and magnesium.

In the fourth aspect, by using a predetermined material for the protective layer, the protective layer can be easily and reliably formed by melting.

According to a fifth aspect of the present invention, there is provided an ink jet recording head according to the first or second aspect, wherein the protective layer is formed of a thermoplastic resin.

In the fifth aspect, by using a thermoplastic resin for the protective layer, the protective layer can be easily and reliably melt-formed.

According to a sixth aspect of the present invention, there is provided an ink jet recording head according to any one of the first to fifth aspects, wherein the protective layer has hydrophilicity.

In the sixth aspect, the hydrophilicity of the pressure generating chamber is improved, and the ink ejection characteristics are improved.

According to a seventh aspect of the present invention, there is provided an ink jet recording apparatus including the ink jet recording head according to any one of the first to sixth aspects.

According to the seventh aspect, an ink jet recording apparatus having improved ink ejection characteristics can be realized.

According to an eighth aspect of the present invention, there is provided a flow path forming substrate in which a pressure generating chamber communicating with a nozzle opening is defined, and a film forming and lithography method on one side of the flow path forming substrate via a diaphragm. A lower electrode composed of a thin film formed by a method, a piezoelectric element composed of a piezoelectric layer and an upper electrode, and a bonding substrate defining a part of the pressure generating chamber on the other surface of the flow path forming substrate. In the method of manufacturing an ink jet recording head, a step of filling the pressure generating chamber with a filler,
A method of manufacturing an ink jet recording head, comprising: a step of bonding the bonding substrate to the other surface of the flow path forming substrate; and a step of removing the filler.

In the eighth aspect, since the joining substrate is joined to the flow path forming substrate in a state where the pressure generating chamber is filled with the filler, the partition does not deform at the time of joining.

According to a ninth aspect of the present invention, in the eighth aspect, the step of removing the filler comprises the step of:
Alternatively, there is provided a method of manufacturing an ink jet recording head, wherein the filler is removed from an ink supply path for supplying ink to the pressure generating chamber.

In the ninth aspect, the filler can be easily and reliably removed from the nozzle opening or the ink supply path.

A tenth aspect of the present invention is the ink jet recording head according to the eighth or ninth aspect, wherein in the step of filling the filler, the filler is melted, filled and cured. Manufacturing method.

According to the tenth aspect, it is possible to reliably prevent deformation of the partition wall when the joining substrate and the flow path forming substrate are joined.

According to an eleventh aspect of the present invention, in any one of the eighth to tenth aspects, the step of removing the filler comprises:
A method for manufacturing an ink jet recording head, characterized in that the filler is melted and removed.

In the eleventh aspect, the filler can be easily and reliably removed by melting the filler.

A twelfth aspect of the present invention is the method according to any one of the eighth to eleventh aspects, wherein the filler has a melting point of 600 to 700.
A method of manufacturing an ink jet recording head, wherein the method is a metal having a temperature of ° C.

In the twelfth aspect, by using a filler having a melting point of a predetermined temperature, it is possible to prevent breakage of the piezoelectric layer and to form the filler by melting.

A thirteenth aspect of the present invention is the method for manufacturing an ink jet recording head according to the twelfth aspect, wherein the metal is selected from the group consisting of aluminum, antimony and magnesium.

In the thirteenth aspect, by using a predetermined material for the filler, the pressure generating chamber can be easily and reliably filled.

A fourteenth aspect of the present invention is the method according to any one of the eighth to thirteenth aspects, wherein the bonding substrate is a silicon single crystal substrate or a glass substrate, and the bonding substrate is bonded to the flow path forming substrate. Then, there is provided a method for manufacturing an ink jet recording head, wherein the two are joined by anodic bonding.

In the fourteenth aspect, the bonding substrate can be easily and reliably bonded to the flow path forming substrate by anodic bonding.

A fifteenth aspect of the present invention is the method for manufacturing an ink jet recording head according to any one of the eighth to eleventh aspects, wherein the filler is a thermoplastic resin.

In the fifteenth aspect, the rigidity of the partition is reliably increased by using a predetermined material for the filler.
The pressure generating chamber can be easily and reliably filled with the filler.

According to a sixteenth aspect of the present invention, in the fifteenth aspect, in the step of bonding the bonding substrate to the flow path forming substrate, the two are bonded via a thermosetting adhesive. In a method for manufacturing an ink jet recording head.

In the sixteenth aspect, the bonding substrate can be easily and reliably bonded to the flow path forming substrate by the adhesive.

A seventeenth aspect of the present invention is the method for manufacturing an ink jet recording head according to the eighth or ninth aspect, wherein the filler has a smaller particle diameter than the nozzle opening.

In the seventeenth aspect, the filler can be easily and reliably removed from the nozzle opening.

An eighteenth aspect of the present invention is the ink jet recording head according to the eighth or ninth aspect, wherein in the step of removing the filler, the filler is dissolved and removed with a solvent. In the manufacturing method.

In the eighteenth aspect, the filler can be easily and reliably removed by the solvent.

According to a nineteenth aspect of the present invention, in any one of the eighth to eighteenth aspects, the step of removing the filler comprises:
A method of manufacturing an ink jet recording head, wherein the method is performed by applying pressure or sucking the filler into the pressure generating chamber.

In the nineteenth aspect, the filler can be removed in a short time and reliably.

[0049]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments.

(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 (a) is a longitudinal direction of a pressure generating chamber of the ink jet recording head. It is sectional drawing, (b) is AA 'sectional drawing of (a).

As shown in the figure, the flow path forming substrate 10 is a silicon single crystal substrate having a plane orientation (110) in this embodiment. One surface of the flow path forming substrate 10 is an opening surface,
On the other surface, an elastic film 50 having a thickness of 0.1 to 2 μm and made of silicon dioxide formed in advance by thermal oxidation is formed.

In the flow path forming substrate 10, pressure generating chambers 12 formed by anisotropic etching and divided by a plurality of partition walls 11 are arranged in parallel in the width direction. On the outside in the longitudinal direction, a communication portion 13 which forms a part of a reservoir 100 which communicates with a reservoir portion of a reservoir forming substrate, which will be described later, and serves as a common ink chamber for each pressure generating chamber 12.
Are formed, and are communicated with one end in the longitudinal direction of each pressure generating chamber 12 via the ink supply path 14.

Further, protective layers 110 are formed at least at the corners in the pressure generating chamber 12. Here, the corner is a region where three or two surfaces of the inner surface of the pressure generating chamber 12 intersect, and the protective layer 110 may be provided at least at the corner where the three surfaces intersect. This protective layer 1
Details of 10 will be described later.

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 The second (11) which forms an angle of about 70 degrees with the (111) plane and forms an angle of about 35 degrees with the above (110).
1) plane appears, and the etching rate of the (111) plane is about 1/18 as compared with the etching rate of the (110) plane.
This is performed using the property of being 0. By such anisotropic etching, two first (111)
Precision processing can be performed based on the depth processing of a parallelogram formed by two surfaces and two oblique second (111) surfaces, and the pressure generating chambers 12 can be arranged at high density.

In this 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 provided on the flow path forming substrate 1.
It is formed by etching until it reaches the elastic film 50 almost through 0. Here, the elastic film 50 is
The amount attacked by the alkaline solution for etching the silicon single crystal substrate is extremely small. Further, each ink supply path 14 communicating with one end of each pressure generating chamber 12 is
It is formed shallower. That is, the ink supply path 14
Is formed by etching (half-etching) the silicon single crystal substrate halfway in the thickness direction. Note that the half etching is performed by adjusting the etching time.

The thickness of such a flow path forming substrate 10 may be determined by selecting an optimum thickness in accordance with the arrangement density of the pressure generating chambers 12. For example, if the arrangement density is about 180 per inch, , The thickness of the flow path forming substrate 10 is 220 μm
However, for example, in the case of arranging at a relatively high density of 200 or more per inch, the thickness of the flow path forming substrate 10 is preferably set to be relatively thin at 100 μm or less. This is because the partition 11 between the adjacent pressure generating chambers 12
This is because the arrangement density can be increased while maintaining the rigidity.

On the opening side of the flow path forming substrate 10,
A nozzle plate 20 having a nozzle opening 21 communicating therewith on the side opposite to the ink supply port 14 of each pressure generating chamber 12 is joined. The nozzle plate 20 has a thickness of, for example, at 0.1 to 1 mm, in the linear expansion coefficient of 300 ° C. or less, for example, ^{2.5~4.5 [× 10 - 6 / ℃} ] glass is, a single crystal Silicon, stainless steel or stainless steel (SU
S). The nozzle plate 20 entirely covers one surface of the flow path forming substrate 10 on one side, and also serves as a reinforcing plate for protecting the flow path forming substrate 10 made of a silicon single crystal substrate from impact or external force.

Here, the size of the pressure generating chamber 12 for applying the ink droplet ejection pressure to the ink and the size of the nozzle opening 21 for ejecting the ink droplet depend on the amount of the ejected ink droplet, the ejection speed, and the ejection frequency. Optimized. For example,
When recording 360 ink droplets per inch, the nozzle openings 21 need to be formed with a diameter of several tens of μm with high accuracy.

The flow path forming substrate 10 and the nozzle plate 2
Examples of the bonding method with 0 include bonding with an adhesive, anodic bonding, and the like. In the present embodiment, the nozzle plate 2
The nozzle plate 20 and the flow path forming substrate 10 were bonded by anodic bonding using a glass substrate as the sample No. 0.

More specifically, the anodic bonding refers to a flow path forming substrate 10 made of a silicon single crystal substrate whose opposite surfaces are polished to a mirror surface, and a nozzle plate 20 made of a glass substrate.
And the whole is heated to near 450 ° C.
A voltage of 000 V is applied to both ends. At this time, even at a temperature equal to or lower than the melting point of the glass, the positive Na ⁺ ions easily move in the glass, and are attracted to the negative electric field to reach the glass surface. On the other hand, a large amount of negative ions remaining in the glass form a space charge layer on the interface with the silicon single crystal substrate,
A strong suction force is generated between the silicon single crystal substrate and the glass substrate, and the flow path forming substrate 10 and the nozzle plate 20 are anodically bonded.

The nozzle plate 20 and the flow path forming substrate 1
As described in detail later, 0 is bonded in a state where the pressure generating chamber 12 is filled with the filler. The filler filled in the pressure generating chamber 12 is melted and removed after both are joined. At this time, the filler remains in at least the corners of the pressure generating chamber 12, and the remaining filler becomes the protective layer 110.

The material of the protective layer 110, that is, the filler is not particularly limited as long as it is higher than the bonding temperature between the nozzle plate 20 and the flow path forming substrate 10 and has a melting point that prevents the piezoelectric layer from being broken. In this embodiment, since the nozzle plate 20 and the flow path forming substrate 10 are joined by anodic bonding using a glass substrate for the nozzle plate 20, the melting point is higher than the heating temperature (450 ° C.) of anodic joining. Temperature at which the piezoelectric layer is not destroyed, that is, 600 ° C.
Metals at 700 ° C., such as aluminum, antimony and magnesium can be used. In this embodiment, aluminum having a melting point of 660 ° C. is used as the protective layer 110 (filler).

As described above, the protective layer 11 is provided in the pressure generating chamber 12.
By providing 0, the hydrophilicity of the inner surface of the pressure generating chamber 12 can be improved, and bubbles in the ink can be prevented from accumulating at corners and the like. For this reason, it is possible to improve the ink ejection characteristics by preventing printing defects and the like.

If the protective layer 110 is provided over the entire inner surface of the pressure generating chamber 12, the pressure generating chamber 12
The ink ejection characteristics can be further improved by improving the hydrophilicity of the inner surface of the ink.

On the other hand, the lower electrode film 60 having a thickness of, for example, about 0.2 μm and the piezoelectric layer 70 having a thickness of, for example, about 1 μm are formed on the elastic film 50 provided on the flow path forming substrate 10. When,
The upper electrode film 80 having a thickness of, for example, about 0.1 μm is laminated and formed by a process described later, and forms the piezoelectric element 300. Here, the piezoelectric element 300 includes the lower electrode film 60,
A portion including the piezoelectric layer 70 and the upper electrode film 80. Generally, one of the electrodes of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are connected to each of the pressure generating chambers 1.
It is structured by patterning every two. Here, a portion which is constituted by one of the patterned electrodes and the piezoelectric layer 70 and in which a piezoelectric strain is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion. In the present embodiment, the lower electrode film 60 is a common electrode of the piezoelectric element 300, and the upper electrode film 8
Although 0 is used as the individual electrode of the piezoelectric element 300, there is no problem even if this is reversed for convenience of a drive circuit and wiring. In any case, the piezoelectric active portion is formed for each pressure generating chamber. Also, here, the piezoelectric element 300
The diaphragm and the vibration plate that is displaced by driving the piezoelectric element 300 are collectively referred to as a piezoelectric actuator. 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.

The upper electrode film 80, which is an individual electrode of the piezoelectric element 300, is connected to an external wiring (not shown) via a lead electrode 90 extending from the vicinity of one end in the longitudinal direction of the piezoelectric element 300 on the elastic film 50. Have been.

Further, the piezoelectric element 30 of the flow path forming substrate 10
On the 0 side, a reservoir forming substrate 30 having a reservoir portion 31 constituting at least a part of the reservoir 100 is joined. In the present embodiment, the reservoir section 31 penetrates the reservoir forming substrate 30 in the thickness direction, and
2 and is communicated with the communicating portion 13 of the flow path forming substrate 10 as described above, and each of the pressure generating chambers 1 is formed.
The two reservoirs 100 serve as a common ink chamber.

As such a reservoir forming substrate 30, it is preferable to use a material having substantially the same thermal expansion coefficient as that of the flow path forming substrate 10, for example, glass, ceramic material or the like. It was formed using a silicon single crystal substrate of the same material as that of No. 10. Thereby, even if both are bonded at a high temperature using a thermosetting adhesive, both can be bonded reliably. Therefore, the manufacturing process can be simplified.

The piezoelectric element 3 of the reservoir forming substrate 30
A piezoelectric element holding portion 32 capable of sealing the space is provided in a region opposed to the piezoelectric element 300 while securing a space that does not hinder the movement of the piezoelectric element 300. Sealed inside. In the present embodiment, the piezoelectric element holding section 32 is formed to have a size that covers the plurality of piezoelectric elements 300 arranged in parallel.

Further, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is joined 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).
One surface of the reservoir 31 is sealed by the sealing film 41. The fixing plate 42 is made of a hard material such as a metal (for example, stainless steel (SUS) having a thickness of 30 μm).
Etc.). The area of the fixing plate 42 facing the reservoir 100 is the opening 4 completely removed in the thickness direction.
Therefore, one surface of the reservoir 100 is sealed with only the sealing film 41 having flexibility, thereby forming a flexible portion 45 that can be deformed by a change in internal pressure.

Further, an ink introduction port 44 for supplying ink to the reservoir 100 is formed on the compliance substrate 40 substantially outside the central portion in the longitudinal direction of the reservoir 100. Further, the reservoir forming substrate 30 is provided with an ink introduction path 36 that communicates the ink introduction port 44 with the side wall of the reservoir 100.

The ink jet recording head according to this embodiment takes in ink from the ink inlet 44 connected to external ink supply means (not shown), and
After the inside is filled with ink from 00 to the nozzle opening 21, each lower electrode film 60 corresponding to the pressure generating chamber 12 is formed according to a recording signal from an external driving circuit (not shown).
By applying a voltage between the upper electrode film 80 and the elastic film 50, the lower electrode film 60 and the piezoelectric layer 70 are flexed and deformed, the pressure in each pressure generating chamber 12 increases, and the nozzle opening 2
An ink droplet is ejected from 1.

Here, a method for manufacturing such an ink jet recording head will be described in detail. FIG. 3 and FIG. 4 are cross-sectional views in the direction in which the pressure generating chambers are arranged, showing the method for manufacturing the ink jet recording head.

First, as shown in FIG. 3A, a wafer of a silicon single crystal substrate to be
Thermal oxidation is performed in a diffusion furnace at 0 ° C. to form an elastic film 50 made of silicon dioxide.

Next, as shown in FIG. 3B, the lower electrode film 60 is formed over the entire surface of the flow path forming substrate 10 on the pressure generating chamber 12 side by sputtering, and is patterned into a predetermined shape. As a material of the lower electrode film 60, platinum,
Iridium and the like are preferred. This is because a piezoelectric layer 70 described later, which is formed by a sputtering method or a sol-gel method, has a thickness of 600 to 1000 in an air atmosphere or an oxygen atmosphere after the film formation.
This is because it is necessary to crystallize by firing at a temperature of about ° C. That is, the material of the lower electrode film 60 must be able to maintain conductivity under such high temperature and oxidizing atmosphere.
In particular, as the piezoelectric layer 70, lead zirconate titanate (PZ
When T) is used, it is desirable that the change in conductivity due to the diffusion of lead oxide is small, and for these reasons, platinum and iridium are preferred.

Next, as shown in FIG. 3C, a piezoelectric layer 70 and an upper electrode film 80 are formed, and only the piezoelectric layer 70 and the upper electrode film 80 are etched to pattern the piezoelectric element 300. .

In the present embodiment, for example, in this embodiment, a so-called sol in which a metal organic material is dissolved and dispersed in a catalyst is applied, dried and gelled, and further baked at a high temperature to form a piezoelectric material made of a metal oxide. The layer 70 was formed by using a so-called sol-gel method. As a material for the piezoelectric layer 70, a PZT-based material is suitable when used in an ink jet recording head. The method for forming the piezoelectric layer 70 is not particularly limited. For example, the piezoelectric layer 70 may be formed by a spin coating method such as a sputtering method or a MOD method (organic metal thermal coating decomposition method).

Further, a method of forming a precursor film of lead zirconate titanate by a sol-gel method, a sputtering method, a MOD method, or the like, and then crystallizing the film at a low temperature by a high pressure treatment in an alkaline aqueous solution may be used. Good.

Further, the upper electrode film 80 only needs to be a material having high conductivity, and many metals such as aluminum, gold, nickel and platinum, and conductive oxides can be used. In the present embodiment, platinum is formed by sputtering.

Next, as shown in FIG. 3D, a lead electrode 90 is formed over the entire surface of the flow path forming substrate 10 and is patterned for each piezoelectric element 300.

The above is the film forming process. After forming the film in this manner, as shown in FIG. 3E, the silicon single crystal substrate is subjected to anisotropic etching with the above-described alkali solution to form the pressure generating chamber 12. Similarly, a communication portion 13 and an ink supply path 14 are formed (not shown).

By a series of film formation and anisotropic etching as described above, a number of chips are simultaneously formed on one wafer, and after the process is completed, a flow path forming substrate of one chip size as shown in FIG. Divide every ten. Then, the nozzle plate 20, the reservoir forming substrate 30, and the compliance substrate 40 are sequentially bonded to and integrated with the divided flow path forming substrate 10 to obtain an ink jet recording head.

Here, a method of joining the flow path forming substrate 10 and the nozzle plate 20 will be described in detail.

First, as shown in FIG. 4A, the pressure generating chamber 12 is filled with a filler 111 with the opening of the pressure generating chamber 12 of the flow path forming substrate 10 facing upward. Note that the shape of the filler 111 is not particularly limited, for example, a chip shape, a granular shape, and the like. In this embodiment, a glass substrate is used for the nozzle plate 20, and the flow path forming substrate 10 and the nozzle plate 20 are joined by anodic joining in a later step.
As 11, granular aluminum having a melting point of 660 ° C. was used.

In the case where non-rusting steel or stainless steel (SUS) is used for the nozzle plate 20, for example,
In a later step, bonding can be performed using an adhesive, for example, a thermosetting adhesive such as an epoxy-based, acrylic-based, urethane-based, or silicon-based adhesive. In the joining with this thermosetting adhesive, the durable temperature of the adhesive is as low as about 200 ° C., and therefore, as a filler, a thermoplastic resin having a melting point lower than the durable temperature (about 200 ° C.), for example, a vinyl chloride resin , Olefin resin (polyethylene, polypropylene), polyamide resin (nylon), fluororesin, polystyrene,
It is preferable to use methacrylic resin, polycarbonate and the like.

Of course, even when a glass substrate or a silicon single crystal substrate is used for the nozzle plate 20, both can be joined with a thermosetting adhesive using a thermoplastic resin as a filler.

Next, as shown in FIG. 4B, the filler 111 in the pressure generating chamber 12 is heated and melted and hardened to form a filling layer 112 on the elastic film 50 side of the pressure generating chamber 12.

As described above, the packed bed 1 is placed in the pressure generating chamber 12.
By providing 12, the rigidity of the partition 11 can be increased. In the present embodiment, the filling layer 112 is formed by melting and curing the filler 111 by heating.
It is not necessary to heat and melt the filler. For example, deformation of the partition 11 can be prevented by densely filling the pressure generating chamber 12 with the granular filler 111. Of course,
The filler 111 may be melted only when it is removed without dissolving it when filling it.

Next, as shown in FIG. 4C, the nozzle plate 20 is joined to the surface of the flow path forming substrate 10 where the pressure generating chamber 12 is open. In the present embodiment, the nozzle plate 20 is bonded by anodic bonding using glass or single crystal silicon. At this time, since the filler 111 of a material having a melting point higher than the anodic bonding heating temperature (approximately 450 ° C.), that is, aluminum having a melting point of 660 ° C. is used as the material of the filling layer 112, the filling layer 112 is not melted. The nozzle plate 20 can be joined with the rigidity of the partition 11 increased. Therefore, even if the nozzle plate 20 is bonded to the flow path forming substrate 10 by applying a load, the partition wall 1
1 can be prevented and the shape of the pressure generating chamber 12 can be made uniform.

Next, as shown in FIG. 4D, the filling layer 112 in the pressure generating chamber 12 is removed. In the present embodiment, the filling layer 112 is discharged from the nozzle opening 21 and removed by heating and melting the filling layer 112.

At this time, for example, the inside of the pressure generating chamber 12 is sucked from the nozzle opening 21 or the ink supply path 14 is sucked.
By pressurizing the inside of the pressure generating chamber 12 by sending air from the side or the like, the filling layer 112 can be removed reliably and in a short time.

When the filler 111 is removed by using a granular member having a smaller diameter than the nozzle opening 21, the filler 111 may be removed by gravity without melting from the nozzle opening 21. Then, the inside of the pressure generating chamber 12 may be suctioned from the nozzle opening 21 to remove the filler. Thereby, the work of melting the filler can be omitted, and the manufacturing process can be simplified.

Further, when melting and removing the filling layer 112,
As described above, the filling layer 112 remains at least at the corners of the inner surface of the pressure generating chamber 12, and the remaining filling layer 1
12 becomes the protective layer 110.

As described above, in the present embodiment, the pressure generating chamber 1
Since the filling layer 112 is provided in the inside 2 and the nozzle plate 20 and the flow path forming substrate 10 are joined, both can be surely joined with the rigidity of the partition wall 11 increased. For this reason, the deformation of the partition 11 can be prevented, the pressure generating chamber 12 can be defined in a uniform shape, and the ink ejection characteristics can be improved.

(Embodiment 2) FIG. 5 is a sectional view showing a manufacturing process of an ink jet recording head according to Embodiment 2.

This embodiment is another example of the manufacturing method.
Specifically, in this example, the filler is melted and removed with a solvent after the flow path forming substrate 10 and the nozzle plate 20 are joined. Note that the manufacturing steps before the joining of the nozzle plate 20 are the same as those in the above-described first embodiment, and thus redundant description will be omitted.

First, as shown in FIG. 5A, the pressure generating chamber 12 of the flow path forming substrate 10 is filled with a filler 111A. The filler 111A is not particularly limited as long as it is a member that can be melted with a solvent. In the present embodiment, granular glass is used.

Next, as shown in FIG. 5B, the nozzle plate 20 is joined to the surface of the flow path forming substrate 10 where the pressure generating chambers 12 open. In the present embodiment, the two are bonded via the thermosetting adhesive 25.

At this time, the nozzle plate 20 must be brought into close contact with the flow path forming substrate 10 by applying a load. However, the rigidity of the partition wall 11 can be improved by densely filling the pressure generating chamber 12 with the filler 111A. Is increased, it is possible to prevent the partition 11 from being deformed by applying a load to the nozzle plate 20. Therefore, the pressure generating chamber 1
2 can be made uniform to improve the ink ejection characteristics.

Next, as shown in FIG. 5C, the filler 111A in the pressure generating chamber 12 is melted by the solvent 120. In the present embodiment, since granular glass is used for the filler 111A, the filler 111A is melted by immersion in a solvent 120 such as hydrofluoric acid.

Next, as shown in FIG. 5D, the flow path forming substrate 10 to which the nozzle plate 20 is bonded is
0, and the molten solvent 120 of the filler 111A
Is removed from the pressure generating chamber 12 through the nozzle opening 21.

[0102] The filler 111
A, the flow path forming substrate 10
And the nozzle plate 20, and the filler 111 A can be removed by the solvent 120. Therefore, the pressure generating chamber 12 can be defined uniformly by preventing the deformation of the partition wall 11, and the ink discharge characteristics can be improved.

When the flow path forming substrate 10 and the nozzle plate 20 are joined by the manufacturing method of the present embodiment, the filler 111A in the pressure generating chamber 12 is completely removed. No protective layer is formed in 12.

(Embodiment 3) FIG. 6 is a sectional view showing a manufacturing process of an ink jet recording head according to Embodiment 3.

The present embodiment is another example of the manufacturing method.
Specifically, in this example, the filler is removed without melting after the flow path forming substrate 10 and the nozzle plate 20 are joined. Note that the manufacturing process up to before the joining of the nozzle plate is the same as that of the first embodiment described above, and a duplicate description will be omitted.

First, as shown in FIG. 6A, the filler 111B is filled in the pressure generating chamber 12 of the flow path forming substrate 10. It is preferable that the filler 111B be filled into the pressure generating chamber 12 as densely as possible, thereby increasing the rigidity of the partition wall 11. In the present embodiment, as the filler 111B, a granular material having a smaller diameter than the opening diameter of the nozzle opening 21, for example, granular glass is used.

Next, as shown in FIG. 6B, the nozzle plate 20 is bonded to the surface of the flow path forming substrate 10 where the pressure generating chambers 12 open. In the present embodiment, both are adhered with the thermosetting adhesive 25 as in the second embodiment.

At this time, similar to the second embodiment,
The nozzle plate 20 must be brought into close contact with the flow path forming substrate 10 by applying a load. However, since the rigidity of the partition walls 11 is increased by densely filling the filler 111B, the load of the nozzle plate 20 is increased. Thereby, deformation of the partition 11 can be prevented. Therefore, the pressure generating chamber 12
Can be made uniform to improve the ink ejection characteristics.

Next, as shown in FIG. 6C, the filler 111B is removed from the nozzle opening 21. In the present embodiment, since the diameter of the filler 111B is smaller than the diameter of the nozzle opening 21, the filler 111B can be removed through the nozzle opening 21. In the removal of the filler 111B, the filler 111 can be easily removed by applying vibration to the flow path forming substrate 10 or sucking the inside of the pressure generating chamber 12 from the nozzle opening 21.

As described above, by using a granular member having a diameter smaller than the diameter of the nozzle opening 21 as the filler 111B, the filler 111B can be more easily removed from the nozzle opening 21.

When the flow path forming substrate 10 and the nozzle plate 20 are joined by the manufacturing method of the present embodiment, the filler 111B in the pressure generating chamber 12 is completely removed. No protective layer is formed in the chamber 12.

(Other Embodiments) One embodiment of the present invention has been described above. However, the basic structure of the ink jet recording head and the method of manufacturing the same are not limited to those described above.

For example, in the first embodiment, the filling layer 112 is formed by melting and filling the filler 111, and then the nozzle plate 20 is joined to melt and remove the filling layer 112. However, the present invention is not limited to this. Instead, for example, the filler 111 may be filled without melting, and after the nozzle plate 20 is joined, the filler 111 may be melted and removed.

Further, for example, in the above-described first to third embodiments, the nozzle plate 20 in which the nozzle openings 21 are formed is used as the bonding substrate. However, the present invention is not limited to this. The pressure generating chamber may be provided at the longitudinal end. FIG. 7 shows such an example.
FIG. 7 is a plan view of the ink jet recording head and a sectional view taken along line BB 'of FIG.

As shown in FIG. 7, the flow path forming substrate 10A has a nozzle opening 21A which communicates with one end of the pressure generating chamber 12 and is formed narrower and shallower than the pressure generating chamber 12. Further, a joining substrate 20A is joined to a surface of the flow path forming substrate 10A where the pressure generating chamber 12 opens.

The joining substrate 20A has a reservoir 100
A, the reservoir forming substrate 30A and the compliance substrate 40A that define
And the reservoir 100A are joined via an ink supply path 14A provided in the joining substrate 20A. Note that an ink introduction path 44A and a flexible portion 45A are formed in the compliance substrate 40A.

Also in the ink jet type recording head having such a configuration, when the bonding substrate 20A is bonded, a filler is provided in the pressure generating chamber 12 to increase the rigidity of the partition 11 and prevent the deformation of the partition 11. As a result, the ink ejection characteristics can be improved. When the filler is removed, the filler can be removed from the nozzle opening 21A or the ink supply path 14A.

The ink jet recording head according to the above-described embodiment constitutes a part of a recording head unit having an ink flow path communicating with an ink cartridge or the like, and is mounted on an ink jet recording apparatus. FIG.
FIG. 2 is a schematic diagram illustrating an example of the ink jet recording apparatus.

As shown in FIG. 8, the recording head units 1A and 1B having ink jet recording heads are provided with detachable cartridges 2A and 2B constituting ink supply means.
The carriage 3 on which B is mounted is provided movably in the axial direction on a carriage shaft 5 attached to the apparatus main body 4. The recording head units 1A and 1B are, for example,
Each of them ejects a black ink composition and a color ink composition.

Then, the driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and a timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted moves along the carriage shaft 5. Moved. On the other hand, the apparatus main 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, which 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.

[0121]

As described above, according to the present invention,
By providing the protective layer at least at the corners of the inner surface of the pressure generating chamber, the hydrophilicity of the inner surface of the pressure generating chamber can be improved, and the ink ejection characteristics can be improved. Further, according to the manufacturing method of the present invention, by increasing the rigidity of the partition wall and joining the joining substrate and the flow path forming substrate, the shape of the pressure generating chamber can be made uniform and the ink ejection characteristics can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of an ink jet recording head according to a first embodiment of the present invention.

FIGS. 2A and 2B are cross-sectional views of an ink jet recording head according to Embodiment 1 of the present invention, in which FIG. 2A is a cross-sectional view of a pressure generating chamber in a longitudinal direction, and FIG. It is.

FIG. 3 is a cross-sectional view in a direction in which pressure generating chambers are arranged, showing a method for manufacturing the ink jet recording head according to Embodiment 1 of the present invention.

FIG. 4 is a cross-sectional view in a direction in which the pressure generating chambers are arranged, illustrating the method for manufacturing the ink jet recording head according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view in a direction in which pressure generating chambers are arranged, showing a method for manufacturing an ink jet recording head according to Embodiment 2 of the present invention.

FIG. 6 is a cross-sectional view in a direction in which pressure generating chambers are arranged, showing a method for manufacturing an ink jet recording head according to Embodiment 3 of the present invention.

FIG. 7 is a plan view showing a modified example of an ink jet recording head according to another embodiment of the present invention, and a sectional view taken along line BB 'of FIG.

FIG. 8 is a schematic diagram of an ink jet recording apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 10, 10A flow path forming substrate 11 partition wall 12, 12A pressure generating chamber 13 communication part 14, 14A ink supply path 20 nozzle plate 20A bonding substrate 21, 21A nozzle opening 30, 30A reservoir forming substrate 40, 40A compliance substrate 50 elastic film 60 Lower electrode film 70 Piezoelectric layer 80 Upper electrode film 90 Lead electrode 100, 100A reservoir 110 Protective layer 111, 111A, 111B Filler 112 Filler layer

Claims (19)

[Claims] 1. A flow path forming substrate formed of a silicon single crystal substrate in which a pressure generating chamber communicating with a nozzle opening is defined, and a lower electrode and a piezoelectric body are provided on one side of the flow path forming substrate via a diaphragm. An ink jet recording head comprising a layer and a piezoelectric element comprising an upper electrode, wherein a protective layer is provided on at least a corner of the inner surface of the pressure generating chamber. 2. The ink jet recording head according to claim 1, wherein the protective layer is provided over the entire inner surface of the pressure generating chamber. 3. The ink jet recording head according to claim 1, wherein the protective layer is formed of a metal having a melting point of 600 to 700 ° C. 4. The ink jet recording head according to claim 3, wherein said metal is selected from the group consisting of aluminum, antimony and magnesium. 5. The ink jet recording head according to claim 1, wherein the protective layer is formed of a thermoplastic resin. 6. The ink jet recording head according to claim 1, wherein the protective layer has hydrophilicity. 7. An ink jet recording apparatus comprising the ink jet recording head according to claim 1. 8. A flow path forming substrate in which a pressure generating chamber communicating with a nozzle opening is defined, and a thin film formed by film formation and lithography on one surface side of the flow path forming substrate via a diaphragm. A method for manufacturing an ink jet recording head, comprising: a lower electrode, a piezoelectric layer, and a piezoelectric element comprising an upper electrode, and a joining substrate defining a part of the pressure generating chamber on the other surface of the flow path forming substrate. In the ink-jet type, comprising a step of filling the pressure generating chamber with a filler, a step of bonding the bonding substrate to the other surface of the flow path forming substrate, and a step of removing the filler. Manufacturing method of recording head. 9. The ink-jet method according to claim 8, wherein in the step of removing the filler, the filler is removed from the nozzle opening or an ink supply path for supplying ink to the pressure generating chamber. Manufacturing method of recording head. 10. The method according to claim 8, wherein in the step of filling the filler, the filler is melted, filled, and cured. 11. The method according to claim 8, wherein in the step of removing the filler, the filler is melted and removed. 12. The method according to claim 8, wherein the filler is a metal having a melting point of 600 to 700 ° C. 13. The method according to claim 12, wherein the metal is selected from the group consisting of aluminum, antimony, and magnesium. 14. The bonding substrate according to claim 8, wherein the bonding substrate is made of a silicon single crystal substrate or a glass substrate, and in the step of bonding the bonding substrate to the flow path forming substrate, both are bonded by anodic bonding. A method of manufacturing an ink jet recording head. 15. The method according to claim 8, wherein the filler is a thermoplastic resin. 16. The method for manufacturing an ink jet recording head according to claim 15, wherein in the step of bonding the bonding substrate to the flow path forming substrate, the two are bonded via a thermosetting adhesive. 17. The method according to claim 8, wherein the filler has a smaller particle size than the nozzle opening. 18. The method according to claim 8, wherein in the step of removing the filler, the filler is dissolved and removed with a solvent. 19. The method of manufacturing an ink jet recording head according to claim 8, wherein the step of removing the filler is performed by pressurizing or suctioning the pressure generating chamber.