JP2000085133A - Manufacture of ink jet type recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an ink jet type recording head, which can uniformalize the characteristics of the head. SOLUTION: In the manufacturing method for an ink jet type recording head, in which each piezoelectric element is formed on a region corresponding to each pressure generating chamber by laminatingly patterning an elastic film 50, a lower electrode layer 60, a piezoelectric body layer 60 and an upper electrode layer 80 on one side of a flow passage forming board 10 and the pressure generating chamber 12 communicating with a nozzle opening is formed by etching the other side of the flow passage forming board 10 respectively, a film stress measuring process for measuring the film stresses of the respective layer on the flow passage forming board 10 and a dimension selecting process for determining the optimum dimensions of the pressure generating chambers 12, ink feeding passages 15 for feeding an ink to the pressure generating chambers 12 and the respective patternings of the respective layers on the basis of the result of the film stress measuring process are equipped after the formation of at least the elastic film 50, the lower electrode layer 60 and the piezoelectric body layer 70 on the flow passage forming board 10, resulting in allowing to nearly uniformalize ink discharging characteristics.

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. The present invention relates to a method of manufacturing an ink jet recording head that discharges ink droplets by using the method.

[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 to pass through the nozzle opening. Two types of ink jet recording heads that eject ink droplets have been commercialized, one using a longitudinal vibration mode piezoelectric actuator that expands and contracts in the axial direction of the piezoelectric element, and the other using a flexural vibration mode piezoelectric actuator. ing.

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.

[0007]

However, in the above-described manufacturing method using the thin film technology and the lithography method,
A pressure generating chamber is formed after patterning of the thin film. At this time, due to the effect of internal stress relaxation of the upper electrode and the piezoelectric layer,
There is a problem in that the diaphragm bends toward the pressure generating chamber, and this deflection remains as initial deformation of the diaphragm.

In particular, when each layer of the piezoelectric element is formed by a sol-gel method or a sputtering method, a firing process at a high temperature is required. Tensile stress occurs. This tensile stress greatly changes the rigidity of the diaphragm. The problem is that slight fluctuations in the manufacturing process change the stress of the film, and the characteristics of the diaphragm and the characteristics of the ink jet recording head differ greatly from manufacturing to manufacturing, resulting in extremely low manufacturing yield. There is.

As the elastic film, in addition to a silicon oxide film, a zirconium oxide film having a high rigidity has been proposed, but the same problem occurs in any case.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a manufacturing method of an eject type recording head capable of making head characteristics uniform.

[0011]

According to a first aspect of the present invention for solving the above-mentioned problems, an elastic film is provided on one surface of a flow path forming substrate.
A lower electrode layer, a piezoelectric layer, and an upper electrode layer are sequentially laminated to form a piezoelectric element in a region corresponding to the pressure generating chamber by patterning each layer, and etching the flow path forming substrate from the other surface side. In a method for manufacturing an ink jet recording head for forming a pressure generating chamber communicating with a nozzle opening, at least the elastic film, the lower electrode layer, and the piezoelectric layer are formed on the flow path forming substrate, and then the flow path forming is performed. A film stress measuring step of measuring a film stress of each layer on the substrate, and an optimal pressure generating chamber and an ink supply path for supplying ink to the pressure generating chamber based on a result of the film stress measuring step, and an optimal patterning of each layer. And a dimension selecting step of determining a dimension.

In the first aspect, the pressure generating chamber, the ink supply path, and the optimal dimensions of the patterning of each layer are determined according to the film stress of each layer on the flow path forming substrate. Can be made substantially uniform, and the production yield can be improved.

According to a second aspect of the present invention, in the first aspect, in the film stress measuring step, the film stress of each of the layers is calculated from a measurement result obtained by measuring an amount of deformation of the flow path forming substrate. And a method of manufacturing an ink jet recording head.

In the second aspect, the film stress of each layer on the flow path forming substrate can be easily calculated.

According to a third aspect of the present invention, in the first or second aspect, in the dimension selecting step, the opening area of the pressure generating chamber is determined to be an optimal size. Manufacturing method.

In the third aspect, by changing the volume of the pressure generating chamber, the ejection characteristics of the ink ejected from the nozzle openings can be easily adjusted to achieve uniformity.

A fourth aspect of the present invention is the method for manufacturing an ink jet recording head according to the third aspect, wherein in the dimension selecting step, the width of the pressure generating chamber is set to an optimal dimension. .

In the fourth aspect, by changing the width of the pressure generating chamber, the volume of the pressure generating chamber is adjusted to achieve uniform discharge characteristics.

According to a fifth aspect of the present invention, in the third or fourth aspect, in the dimension selecting step, the length of the pressure generating chamber in the longitudinal direction is set to an optimum dimension. In the method of manufacturing the head.

In the fifth aspect, the volume of the pressure generating chamber is adjusted by changing the length of the pressure generating chamber,
To achieve uniform discharge characteristics.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, in the dimension selecting step, at least one of a depth and a width of the ink supply path is changed to thereby provide the ink supply path. A method for manufacturing an ink jet recording head, characterized in that the flow path area is optimized.

In the sixth aspect, the discharge characteristics are made uniform by adjusting the flow path resistance of the ink supply path.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, in the dimension selecting step, the thicknesses of the elastic film and the lower electrode layer on both sides in the width direction of the piezoelectric element are optimized. The method for manufacturing an ink jet recording head is characterized in that the dimensions are determined as follows.

According to the seventh aspect, the amount of deformation and the rigidity of the elastic film caused by driving the piezoelectric element can be adjusted.

According to an eighth aspect of the present invention, in any one of the first to seventh aspects, each of the layers constituting the piezoelectric element is formed of a sol-gel.
A method of manufacturing an ink jet recording head, which is formed by a gel method or a sputtering method.

In the eighth aspect, the yield can be effectively improved by deciding the optimum size according to the film stress.

According to a ninth aspect of the present invention, in any one of the first to eighth aspects, the pressure generation chamber is formed on a silicon single crystal substrate by anisotropic etching, and each layer of the piezoelectric element is formed by film formation. A method of manufacturing an ink jet type recording head characterized by being formed by a lithography method.

In the ninth aspect, an ink jet recording head having high-density nozzle openings can be manufactured in a large amount and relatively easily.

According to a tenth aspect of the present invention, in any one of the first to ninth aspects, a reservoir communicating with the pressure generating chamber is defined in the flow path forming substrate, and the nozzle having the nozzle opening is provided. A method for manufacturing an ink jet recording head, wherein a plate is bonded.

According to the tenth aspect, an ink jet recording head that discharges ink from the nozzle openings can be easily realized.

According to an eleventh aspect of the present invention, in any one of the first to tenth aspects, a common ink chamber for supplying ink to the pressure generation chamber, the pressure generation chamber, A method of manufacturing an ink jet type recording head, wherein a flow path unit for forming a flow path communicating with the nozzle opening is joined.

In the eleventh aspect, the ink is supplied from the flow channel unit to the pressure generating chamber, and is discharged from the nozzle opening.

According to a twelfth aspect of the present invention, in the ink jet recording head according to the eleventh aspect, the flow path unit is joined to the flow path forming substrate on the pressure generating chamber opening side. In the manufacturing method.

In the twelfth aspect, the ink from the flow channel unit is supplied from the opening side of the pressure generating chamber.

A thirteenth aspect of the present invention is the manufacturing method of the ink jet recording head according to the eleventh aspect, wherein the flow path unit is joined to the flow path forming substrate on the side where the piezoelectric element is formed. In the way.

In the thirteenth aspect, the ink from the flow channel unit is supplied to the pressure generating chamber via the communication path that opens on the side where the piezoelectric element is formed.

[0037]

FIG. 1 is an assembled perspective view showing an ink jet recording head according to an embodiment of the present invention, and FIGS. 2 (a) and 2 (b) are longitudinal views of one of the pressure generating chambers. It is a figure which shows each cross-section in the direction and the direction which intersects it.

As shown in the figure, the flow path forming substrate 10 is made of a silicon single crystal substrate having a plane orientation (110) in this embodiment. As the flow path forming substrate 10, usually 150 to 3
A thickness of about 00 μm is used.
Those having a thickness of about 0 to 280 μm, more preferably about 220 μm are suitable. This is because the arrangement density can be increased while maintaining the rigidity of the partition wall between the adjacent pressure generating chambers.

One surface of the flow path forming substrate 10 is an opening surface, and the other surface is formed with a 0.1 to 2 μm-thick elastic film 50 made of silicon dioxide previously formed by thermal oxidation.

On the other hand, the opening surface of the flow path forming substrate 10 is anisotropically etched on a silicon single crystal substrate,
Row 1 of pressure generating chambers 12 partitioned by a plurality of partition walls 11
3 are arranged in a substantially U-shape so as to surround three rows of the two rows of pressure generating chambers 12, and each of the pressure generating chambers 1.
An ink supply port 15 for communicating the reservoir 2 with the reservoir 14 at a constant fluid resistance is formed. Note that an ink inlet 16 for supplying ink to the reservoir 14 from the outside is formed at a substantially central portion of the reservoir 14.

Here, in the anisotropic etching, when the silicon single crystal substrate is immersed in an alkaline solution such as KOH, the substrate is gradually eroded, and the first (111) plane perpendicular to the (110) plane and the first (111) plane A second (1) which forms an angle of about 70 degrees with the (111) plane and forms an angle of about 35 degrees with the (110) plane.
11) plane, and the etching rate of the (111) plane is about 1/1 compared to the etching rate of the (110) plane.
This is performed using the property of being 80.
By such anisotropic etching, two first (11
Precision processing can be performed based on depth processing of a parallelogram formed by the 1) plane and two oblique second (111) planes, and the pressure generating chambers 12 can be arranged at high density. it can.

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 port 15 communicating with one end of each pressure generating chamber 12 is connected to one of the pressure generating chambers 12.
It is formed shallower. That is, the ink supply port 15
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.

On the opening side of the flow path forming substrate 10,
A nozzle plate 18 in which a nozzle opening 17 communicating with the ink supply port 15 of each pressure generating chamber 12 on the opposite side is formed is fixed via an adhesive or a heat welding film. The thickness of the nozzle plate 18 is, for example, 0.1 to 1
mm, the coefficient of linear expansion is 300 ° C. or less, for example, 2.5 to
It is made of 4.5 [× 10 ⁻⁶ / ° C.] glass-ceramic or non-rusting steel. The nozzle plate 18 entirely covers one surface of the flow path forming substrate 10 on one surface, and also serves as a reinforcing plate for protecting the silicon single crystal substrate from impact and external force.

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 17 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 17 need to be formed with a diameter of several tens of μm with high accuracy.

On the other hand, on the elastic film 50 on the side opposite to the opening surface of the flow path forming substrate 10, a thickness of, for example, about 0.5 μm
A lower electrode film 60, a piezoelectric film 70 having a thickness of, for example, about 1 μm, and an upper electrode film 80 having a thickness of, for example, about 0.1 μm are formed by lamination in a process to be described later.
0. Here, the piezoelectric element 300 refers to a portion including the lower electrode film 60, the piezoelectric film 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 film 70 are patterned for each pressure generating chamber 12. Here, a portion which is constituted by one of the patterned electrodes and the piezoelectric film 70 and in which a piezoelectric strain is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion 320. In the present embodiment, the lower electrode film 60 is used as a common electrode of the piezoelectric element 300, and the upper electrode film 80 is used as an individual electrode of the piezoelectric element 300. However, there is no problem even if the upper electrode film 80 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 combination of the piezoelectric element 300 and the vibration plate whose displacement is generated by driving the piezoelectric element 300 is referred to as a piezoelectric actuator. In the example described above, the elastic film 50 and the lower electrode film 6
Although 0 functions as a diaphragm, the lower electrode film may also serve as an elastic film.

Here, a process for forming the piezoelectric film 70 and the like on the flow path forming substrate 10 made of a silicon single crystal substrate will be described with reference to FIG.

As shown in FIG. 3A, first, a wafer of a silicon single crystal substrate serving as the flow path forming substrate 10 is
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, a lower electrode film 60 is formed by sputtering. Pt or the like is preferable as the material of the lower electrode film 60. This is because a piezoelectric film 70 to be described later, which is formed by sputtering or a sol-gel method, has a thickness of 600 to 100
This is because it is necessary to perform crystallization by firing at a temperature of about 0 ° C. That is, the material of the lower electrode film 60 must be able to maintain conductivity at such a high temperature and in an oxidizing atmosphere. In particular, when PZT is used for the piezoelectric film 70, the conductivity of the material by diffusion of PbO is increased. It is desirable that there is little change in sex, and Pt is preferred for these reasons.

Next, as shown in FIG. 3C, a piezoelectric film 70 is formed. In this embodiment, a so-called sol in which a metal organic substance is dissolved and dispersed in a solvent is applied, dried, and gelled,
Further, the film was formed using a so-called sol-gel method in which a piezoelectric film 70 made of a metal oxide was obtained by firing at a high temperature. As a material for the piezoelectric film 70, a lead zirconate titanate (PZT) -based material is suitable when used in an ink jet recording head. The piezoelectric film 70
The film forming method is not particularly limited, and may be formed by, for example, a sputtering method.

Next, as shown in FIG. 3D, an upper electrode film 80 is formed. The upper electrode film 80 only needs to be a material having high conductivity, and many metals such as Al, Au, Ni, and Pt, and a conductive oxide can be used. In the present embodiment, P
t was formed by sputtering. By the above-described processes, each layer constituting the piezoelectric element 300 is formed.

Here, in the present embodiment, the optimal size of the opening area of the pressure generating chamber 12 is determined according to at least the film stress of the elastic film 50, the lower electrode film 60, and the piezoelectric film 70.

First, the elastic film 5 is placed on the flow path forming substrate 10.
In a state where the lower electrode film 60, the piezoelectric film 70, and the upper electrode film 80 are formed, the film stresses thereof are measured. As a method of measuring the film stress, for example, as shown in FIG. 4, a deformation amount D ₁ of the flow path forming substrate 10 per a predetermined length L ₁ of the flow path forming substrate (wafer) 10 is measured. It can be calculated from that value. In the present embodiment, the upper electrode film 80
Is formed, the film stress is measured. However, the present invention is not limited to this. The film stress may be measured after at least the piezoelectric film 70 is formed.

Next, the optimum size of the pressure generating chamber 12 is determined based on the calculated film stress. In the present embodiment, by changing the width of the pressure generating chamber 12, the opening area of the pressure generating chamber 12 is optimized.

This is performed in order to adjust the variation in the ink ejection characteristics due to the film stress of each layer formed on the flow path forming substrate. That is, when the pressure generating chamber 12 is formed, this is performed in order to secure the ink amount in the pressure generating chamber 12 in response to the bending deformation of the elastic film in the region facing the pressure generating chamber 12 due to the film stress.

In the film stress measuring step and the dimension selecting step, when the deformation amount D ₁ of the flow path forming substrate 10 is measured in advance, the pressure generation chamber 12 corresponding to the deformation amount D ₁ is actually measured.
The width of the pressure generating chamber 12 is determined by referring to a conversion table or the like in which the size of the pressure generation chamber 12 is determined. For example, in the present embodiment, the width of the pressure generating chamber 12 when the deformation amount of the flow path forming substrate 10 is D ₁ = 30 μm when the predetermined length L ₁ = 30 mm of the flow path forming substrate 10 is a reference. The width of the pressure generating chamber 12 is increased or decreased. That is, in response to the measurement results of the amount of deformation D ₁ to determine the optimum size of the pressure generating chamber 12.

Note that such a flow path forming substrate (wafer)
In No. 10, the direction of the largest deformation is determined by the crystal orientation of the substrate. Therefore, the measurement of the deformation amount D ₁ is preferably measured in the direction of the largest deformation.

In this embodiment, the flow path forming substrate 10
Although the deformation amount D ₁ of the and to calculate the film stress is not limited to this, for example, may be measured directly film stress by X-ray diffraction or the like.

Next, as shown in FIG. 5, the lower electrode film 60, the piezoelectric film 70 and the upper electrode film 80 are patterned.

First, as shown in FIG. 5A, the lower electrode film 60, the piezoelectric film 70 and the upper electrode film 80 are etched together to pattern the entire pattern of the lower electrode film 60. Next, as shown in FIG. 5B, the piezoelectric film 70 and the upper electrode film 80 are etched to pattern the piezoelectric active portion 320.

After patterning the lower electrode film 60 and the like as described above, preferably, at least the periphery of the upper surface of each upper electrode film 80, and the piezoelectric film 70 and the lower electrode film 60 are preferably formed.
Is formed so as to cover the side surfaces of the substrate (see FIG. 2).

Each of the piezoelectric active portions 3 of the insulator layer 90
A contact hole 90a is formed in a part of the portion corresponding to one longitudinal end of the nozzle opening 20 on the side of 20. One end is connected to each upper electrode film 80 through the contact hole 90a, and the other end is formed with a lead electrode 100 extending to a connection terminal portion such as an ACF (anisotropic conductive film).

Such an insulator layer and the lead electrode 100
FIG.

First, as shown in FIG. 6A, an insulator layer 90 is formed so as to cover the periphery of the upper electrode film 80 and the side surfaces of the piezoelectric film 70 and the lower electrode film 60. This insulator layer 9
In this embodiment, 0 is a negative photosensitive polyimide.

Next, as shown in FIG. 6B, by patterning the insulator layer 90, each of the pressure generating chambers 12 is formed.
A contact hole 90 is formed in a portion corresponding to the longitudinal end of the contact hole 90.
a is formed.

Next, for example, a lead electrode 100 is formed by depositing a conductor such as Ti-Au on the entire surface and then patterning it.

The above is the film forming process. After forming the film in this manner, as shown in FIG. 6C, the silicon single crystal substrate is subjected to anisotropic etching with the above-described alkali solution to form the pressure generating chamber 12 and the like. At this time, the pressure generating chambers 12 are formed for each of the flow path forming substrates (wafers) 10 using a mask pattern corresponding to the optimal size of the pressure generating chambers 12 determined as described above.

FIG. 7 is a plan view of a main part of the ink jet recording head according to the first embodiment.

[0068] As shown in FIG. 7, in this embodiment, the pressure generating chamber 12, as width W ₁ than the width W of the pressure generating chamber 12A as a reference, has been modified so that the opening area increases .

Here, the pressure generating chamber 12A serving as a reference is, for example, in this embodiment, as described above, the flow path forming substrate (wafer) 10 having a predetermined length L ₁ = 30 mm. for 10 deformation amount D ₁ = 30 [mu] m of are of a width W of the pressure generating chamber 12A serving as the reference, for example, it is set to 50 [mu] m.

On the other hand, in the present embodiment, when the deformation amount D ₁ of the flow path forming substrate 10 is larger than the reference amount, for example, D ₁ = 40 μm, the pressure generation chamber 12 is set to the width W, for example. ₁ = 52.5 μm.

As described above, when the film stress is large on the tensile side in accordance with the amount of deformation of the flow path forming substrate (wafer) 10, that is, the stress of the film formed on the flow path forming substrate, The size of the pressure generating chamber 12 is determined to be an optimal size so that the rigidity of the piezoelectric actuator is small and the displacement is large. Thereby, the amount of ink in the pressure generating chamber 12 can be secured, and the rigidity of the diaphragm for each head can be made substantially uniform. As a result, the ejection characteristics such as the ink ejection amount and the ink ejection speed by driving the piezoelectric element 300 can be made substantially uniform, and the production yield can be significantly improved.

In the above-described series of film formation and anisotropic etching, a large number of chips are simultaneously formed on one wafer, and after completion of the process, a flow path of one chip size as shown in FIG. It is divided for each forming substrate 10. Also,
The nozzle plate 18 is adhered to the divided flow path forming substrate 10 to form an ink jet recording head. The ink jet recording head thus configured takes in ink from an ink inlet 16 connected to an external ink supply unit (not shown), fills the interior from the reservoir 14 to the nozzle opening 11 with ink, and then fills the inside with ink (not shown). In accordance with a recording signal from an external drive circuit, a voltage is applied between the lower electrode film 60 and the upper electrode film 80 via the lead electrode 100, and the elastic film 50, the lower electrode film 60, and the piezoelectric film 70 are flexibly deformed. By doing so, the pressure in the pressure generating chamber 12 increases, and ink droplets are ejected from the nozzle opening 17.

In this embodiment, the opening area of the pressure generating chamber 12 is optimized by changing the width of the pressure generating chamber 12. However, the present invention is not limited to this. For example, FIG. as shown, as long L ₁ than the length L of the pressure generating chamber 12A of the reference length of the pressure generating chamber 12, it may be the optimum size of the opening area. With such a configuration, the characteristics of the head can be made substantially uniform, as in the above-described embodiment.

(Embodiment 2) FIG. 9 is a sectional view of a main part of an ink jet recording head according to Embodiment 2.

In the present embodiment, for example, when the film stress is larger than the reference value, instead of changing the size of the pressure generating chamber 12, the thickness of the diaphragm on both sides in the width direction of the piezoelectric body active portion 320 is reduced. This is an example in which the rigidity of the diaphragm is reduced.

In this embodiment, as shown in FIG. 9, the pressure generating chamber 12 is formed to have the same size as the reference pressure generating chamber 12A, and the width of the piezoelectric active portion 320 in the width direction is changed according to the film stress. It is the same as the first embodiment except that the thickness t of the lower electrode films 60 on both sides is set to an optimum thickness.

With such a configuration, when the stress of the diaphragm is too large, the rigidity of the diaphragm can be reduced, and the ink discharge characteristics of each head can be made substantially uniform as in the first embodiment. can do.

In this embodiment, the piezoelectric active portion 32
The thickness of the lower electrode film 60 is not limited to a part in the thickness direction of the lower electrode film 60 on both sides in the width direction. Deformation amount D ₁
May be determined in correspondence with. Therefore, for example, if the deformation amount D ₁ is relatively large, the lower electrode film 60 may be completely removed to set t = 0, and
For example, when the deformation amount D ₁ is greater may be removed correspondingly to a part in the thickness direction of the elastic film 50.

(Embodiment 3) FIG. 10 is a sectional view of an essential part of an ink jet recording head according to Embodiment 3.

In this embodiment, as shown in FIG.
Similar to Embodiment 2, when the film stress is larger than the reference value,
The size of the pressure generation chamber 12 is the same as that of the reference pressure generation chamber 12A.
Each pressure generating chamber 12 and the reservoir 14
The ink supply port 15 that communicates with the
Deformation amount D₁Ink supply when is the reference value 15A
It is also shallow. The depth of the ink supply port 15
Adjust the etching time and perform half etching
It may be done by doing.

As a result, the flow path resistance increases at the end of the pressure generating chamber 12 opposite to the nozzle opening, so that even if the piezoelectric element is driven under the same conditions, the amount of ink ejected increases. I do. Therefore, as described above, the pressure generating chamber 1
The discharge performance can also be adjusted by changing the flow path resistance at the end opposite to the nozzle opening of No. 2,
As in the above-described embodiment, the ejection characteristics of each head can be made substantially uniform.

In this embodiment, the ink supply port 15
The flow path resistance is adjusted by changing the depth of the ink supply port. However, the present invention is not limited to this. For example, ink supply ports having different widths may be formed by changing a mask pattern.

(Other Embodiments) The embodiments of the present invention have been described above, but the basic structure of the ink jet recording head is not limited to the above.

Further, for example, in the above-described embodiment, the reservoir 14 is formed together with the pressure generating chamber 12 in the flow path forming substrate 10, but a member forming the common ink chamber is provided so as to overlap the flow path forming substrate 10. You may.

FIG. 11 shows a partial cross section of the ink jet recording head thus constructed. In this embodiment,
Nozzle plate 120A with nozzle openings 11A drilled
Sealing plate 160, common ink chamber forming plate 170, thin plate 180, and ink chamber side plate 1
The nozzle communication port 3 for communicating the pressure generating chamber 12A and the nozzle opening 11A so as to be sandwiched and penetrate therethrough.
1 is arranged. That is, the common ink chamber 32 is defined by the sealing plate 160, the common ink chamber forming plate 170, and the thin plate 180, and each of the pressure generating chambers 12A and the common ink chamber 3
2 is communicated through an ink communication hole 33 formed in the sealing plate 160. The sealing plate 160 is also provided with an ink introduction hole 34 for introducing ink into the supply ink chamber 32 from outside. Also, the ink chamber side plate 19 located between the thin plate 180 and the nozzle plate 120A.
0 is a penetration portion 35 at a position facing each supply ink chamber 32.
Is formed to allow the thin wall 180 to absorb the pressure, which is generated at the time of discharging the ink droplets, toward the side opposite to the nozzle opening 11A, thereby allowing other pressure generating chambers to absorb the pressure. In addition, unnecessary positive or negative pressure can be prevented from being applied via the common ink chamber 32. Note that the thin plate 180 and the ink chamber side plate 190 may be formed integrally.

In each of the embodiments described above, a thin-film type ink jet recording head which can be manufactured by applying a film forming and lithography process is described as an example.
Of course, the present invention is not limited to this. For example, an inkjet type having various structures, such as a type in which a pressure generating chamber is formed by laminating substrates, or a type in which a green sheet is attached or a piezoelectric film is formed by screen printing or the like. The present invention can be applied to a recording head.

Further, the example in which the insulator layer is provided between the piezoelectric element and the lead electrode has been described. However, the present invention is not limited to this. For example, without providing the insulator layer, each of the upper electrodes may be anisotropically conductive. The film may be thermally welded, and the anisotropic conductive film may be connected to a lead electrode, or may be connected using various bonding techniques such as wire bonding.

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.

[0089]

As described above, according to the present invention,
After forming an elastic film, a lower electrode film, a piezoelectric film, and an upper electrode film on the flow path forming substrate, these film stresses are measured, and the size of the pressure generating chamber or the flow path resistance is determined according to the value. Since the adjustment is performed, the amount of deformation of the diaphragm caused by driving the piezoelectric element of each head can be made substantially uniform. Therefore, the ink discharge performance of each head can be made substantially uniform, and the yield can be improved.

[Brief description of the drawings]

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

FIG. 2 is a plan view and a cross-sectional view of the inkjet recording head according to the first embodiment of the present invention, showing the same.

FIG. 3 is a cross-sectional view illustrating a thin-film manufacturing process according to the first embodiment of the present invention.

FIG. 4 is a side view schematically showing a deformed state of a substrate after a thin film is formed according to the embodiment.

FIG. 5 is a cross-sectional view illustrating a thin-film manufacturing process according to the first embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating a thin-film manufacturing process according to the first embodiment of the present invention.

FIG. 7 is a plan view of a main part of the inkjet recording head according to the first embodiment of the invention.

FIG. 8 is a main part plan view showing a modification of the ink jet recording head according to the first embodiment of the present invention.

FIG. 9 is a cross-sectional view of a main part of an ink jet recording head according to a second embodiment of the invention.

FIG. 10 is a sectional view of a main part of an ink jet recording head according to a third embodiment of the invention.

FIG. 11 is a sectional view of a main part of an ink jet recording head according to another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 flow path forming substrate 12 pressure generating chamber 50 elastic film 60 lower electrode film 70 piezoelectric film 80 upper electrode film 90 insulating layer 100 lead electrode 300 piezoelectric element 320 piezoelectric active part

Claims (13)

[Claims] An elastic film, a lower electrode layer, a piezoelectric layer, and an upper electrode layer are sequentially laminated on one surface of a flow path forming substrate, and each layer is patterned to form a piezoelectric element in a region corresponding to the pressure generating chamber. Forming a pressure generating chamber communicating with the nozzle opening by etching the flow path forming substrate from the other surface side, at least the elastic film on the flow path forming substrate, After forming the lower electrode layer and the piezoelectric layer, a film stress measuring step of measuring a film stress of each layer on the flow path forming substrate; and the pressure generating chamber and the pressure generating chamber based on a result of the film stress measuring step. A method for manufacturing an ink jet recording head, comprising: an ink supply path for supplying ink to a chamber; and a dimension selecting step of determining an optimal dimension for patterning each of the layers. 2. The method according to claim 1, wherein in the film stress measuring step, the film stress of each of the layers is calculated from a measurement result obtained by measuring a deformation amount of the flow path forming substrate. . 3. The method according to claim 1, wherein in the dimension selecting step, an opening area of the pressure generating chamber is determined to an optimal size. 4. The method according to claim 3, wherein in the dimension selecting step, the width of the pressure generating chamber is set to an optimal dimension. 5. The method according to claim 3, wherein in the dimension selecting step, a length of the pressure generating chamber in a longitudinal direction is set to an optimal dimension. 6. The method according to claim 1, wherein in the dimension selecting step, at least one of a depth and a width of the ink supply path is changed so that a flow path area of the ink supply path is optimized. A method for manufacturing an ink jet recording head. 7. The method according to claim 1, wherein in the dimension selecting step, the thicknesses of the elastic film and the lower electrode layer on both sides in the width direction of the piezoelectric element are set to optimal dimensions. Of producing an ink jet recording head. 8. A method for manufacturing an ink jet recording head according to claim 1, wherein each layer constituting said piezoelectric element is formed by a sol-gel method or a sputtering method. 9. The pressure generating chamber according to claim 1, wherein the pressure generating chamber is formed on a silicon single crystal substrate by anisotropic etching, and each layer of the piezoelectric element is formed by film formation and lithography. A method for manufacturing an ink jet recording head. 10. The flow path forming substrate according to claim 1, wherein a reservoir communicating with the pressure generating chamber is defined in the flow path forming substrate, and a nozzle plate having the nozzle opening is joined thereto. Of manufacturing an ink jet recording head. 11. The flow channel forming substrate according to claim 1, wherein a common ink chamber for supplying ink to the pressure generating chamber and a flow communicating the pressure generating chamber and the nozzle opening are provided in the flow path forming substrate. A method of manufacturing an ink jet type recording head, wherein a flow path unit forming a path is joined to the flow path unit. 12. The method according to claim 11, wherein the flow path unit is joined to the flow path forming substrate on the pressure generating chamber opening side. 13. The method according to claim 11, wherein the flow path unit is joined to the flow path forming substrate on the side where the piezoelectric element is formed.