JP2003118114A - Ink jet head and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely jet ink droplets and reduce cross talks between ink chambers. SOLUTION: In the multi-nozzle ink jet head having a plurality of nozzles 11 for jetting ink droplets and a plurality of ink chambers 21 formed corresponding to the nozzles 11, a diaphragm 3 is set to each ink chamber 21, and a volume change of the ink chamber by buckling of the diaphragm 3 is utilized to jet ink droplets, whereby the jet efficiency for ink droplets is enhanced. Moreover, grooves are set to boundaries of ink chambers 21, thereby preventing vibration from being transmitted to the adjacent ink chambers 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-demand type ink jet head for ejecting ink droplets to form recording dots on a recording paper and a method for manufacturing the same.

[0002]

2. Description of the Related Art As a recording head (inkjet head) of an inkjet printer, Japanese Patent Laid-Open No. 2-3054
No. 3, the plate-shaped diaphragm is deformed by generating a temperature gradient in the plate-shaped diaphragm of a cantilever beam or a double-supported beam to generate a thermal stress due to a thermal expansion coefficient of a constituent material. There is disclosed a recording head having a structure in which a recording dot is ejected from a nozzle by ejecting an ink droplet with a pressure that occurs occasionally.

In the recording head described in this publication, a cantilevered beam or a doubly supported beam-like vibrating plate is deformed toward the nozzle plate side by thermal strain, and the pressure of the ink chamber is increased to eject ink droplets from the nozzle. It has a structure.

[0004]

However, the recording head having the above-mentioned structure has the following problems.

(1) Since the pressure generating member has a cantilevered structure or a double-supported beam structure and is a structure that stirs ink in the ink chamber, pressure leaks. Therefore, it is difficult to generate a large pressure in the ink chamber, and a large amount of energy is required to eject the ink.

(2) When a multi-nozzle head is constructed, the vibration of the pressure generating member is transmitted to the adjacent channels (ink chambers), which causes a problem of crosstalk.

The present invention has been made in order to solve such a problem. It is possible to reliably eject ink droplets without leaking the pressure in the ink chambers, and moreover, to cross the ink chambers. An object is to provide a multi-nozzle inkjet head capable of reducing talk. Moreover, it aims at providing the manufacturing method which can manufacture easily the inkjet head with stable performance.

[0008]

An ink jet head of the present invention is a nozzle plate having a plurality of nozzles for ejecting ink droplets, a plurality of ink chambers formed corresponding to the nozzles, and each ink chamber. In a multi-nozzle inkjet head having an ink flow path for supplying ink to the ink and an ink supply port for guiding the ink to the ink flow path,
A diaphragm is formed in each ink chamber, and the ink droplets are ejected from the nozzle by the pressure generated by the volume change of the ink chamber due to the buckling deformation of the diaphragm. Is characterized by being provided.

According to the ink jet head of the present invention,
Since the volume change of the ink chamber due to the deformation of the diaphragm is used for ejecting ink droplets, there is no pressure leakage compared with the conventional cantilever beam or double-supported beam fan structure.
Ink droplets can be efficiently ejected. Furthermore, since each pressure chamber is separated by the groove, vibration is not transmitted to the adjacent ink chamber, and crosstalk can be reduced.

In the ink jet head of the present invention,
If the diaphragm itself is buckled and deformed by thermal expansion, the ink droplets can be efficiently ejected with a simple structure, so that the cost can be reduced.

In the ink jet head of the present invention,
If the diaphragm is made of metal, the thermal conductivity and thermal expansion of the diaphragm are increased, so that high efficiency can be realized. Further, in this case, the metal forming the diaphragm is preferably an electrothermal conversion element. When the diaphragm itself is used as the electrothermal conversion element in this manner, it is not necessary to provide the electrothermal conversion element separately from the diaphragm, so that the structure / process can be simplified and the cost can be reduced.

In the ink jet head of the present invention,
If a material with a coefficient of thermal expansion smaller than that of the diaphragm is provided on the surface of the diaphragm opposite to the ink chamber, and the diaphragm is deformed toward the ink chamber when current is supplied, ink droplets are ejected vigorously from the nozzle. be able to.

That is, for a diaphragm made of metal, when the current is supplied (when heated), when the current is cut off (when cooled)
Since the deformation speed is faster than that of the above, by utilizing this point, the diaphragm is deformed toward the ink chamber side when the current is supplied, and the volume of the ink chamber sharply decreases when the current is supplied, causing the ink droplets to drop. It can spurt vigorously from.

In the ink jet head of the present invention,
As a method of supplying current to the electrothermal conversion element that constitutes the diaphragm, that is, the vibrating electrothermal conversion element, the method of connecting the diaphragm to the wiring pattern formed on the substrate having the ink chamber by wire bonding is the most suitable. is there.

In the manufacturing method of the present invention, a nozzle plate having a plurality of nozzles for ejecting ink droplets, a plurality of ink chambers formed corresponding to the nozzles, and ink for supplying ink to each ink chamber are provided. It has a flow path and an ink supply port for guiding ink to the ink flow path, and is configured to eject an ink droplet from a nozzle according to a pressure change of the ink chamber, and a groove is provided at a boundary of each ink chamber. In a process of manufacturing a multi-nozzle inkjet head, at least one through hole is formed in a substrate forming the ink chamber, and the through hole is used as an alignment mark when the nozzle plate is bonded to the substrate. To be

According to the manufacturing method of the present invention, the alignment between the substrate having the ink chambers and the nozzle plate having the nozzles can be performed easily and accurately.

In the manufacturing method of the present invention, if the through hole used for the alignment mark is formed in the step of forming the ink supply port, the process is simplified and the cost can be reduced.

According to the manufacturing method of the present invention, a nozzle plate having a plurality of nozzles for ejecting ink droplets, a plurality of ink chambers formed corresponding to the nozzles, and ink for supplying ink to each ink chamber are provided. In addition to having a flow path and an ink supply port that guides ink to the ink flow path, a diaphragm is formed in each ink chamber, and ink drops due to the pressure generated by the volume change of the ink chamber due to the buckling deformation of the diaphragm. Is configured to eject from the nozzle,
In the process of manufacturing an inkjet head in which a groove is provided at the boundary of each ink chamber, at least one through hole is formed in the substrate forming the ink chamber, and the through hole is adhered to the nozzle plate on the substrate. It is characterized by using it as an alignment mark.

According to the manufacturing method of the present invention, the alignment between the substrate having the ink chamber and the diaphragm and the nozzle plate having the nozzle can be easily and accurately performed.

In the manufacturing method of the present invention, if the ink chambers are formed by anisotropic etching of silicon, a plurality of ink chambers can be made to have the same size, so that it is possible to realize a head having no variation in performance. Further, if the ink flow paths are formed by anisotropic etching of silicon, a plurality of ink flow paths can be made to have the same size, so that it is possible to realize a head with no variation in performance.

Furthermore, if the ink chamber, the ink flow path and the ink supply port are formed by anisotropic etching of one silicon substrate, they can be manufactured in the same process, so that the cost can be reduced.

In the manufacturing method of the present invention, if the ink chamber and the ink flow path are formed by aligning with the through-hole as a reference, highly accurate alignment becomes possible, and high resolution, miniaturization, and Cost reduction is possible.

In the manufacturing method of the present invention, the diaphragm is made of metal, the side wall of the ink chamber other than the diaphragm is made of silicon, and the thermal conductivity is provided at the boundary between the silicon and the diaphragm made of metal. It is also possible to provide a small film. In this way, the diaphragm that buckles and deforms becomes a heat insulating structure,
The heating efficiency can be improved. Further, if a Ta film is provided on the base of the diaphragm, the adhesion between the diaphragm and the side wall of the ink chamber becomes strong and the reliability becomes high.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view (A) and a plan view (B) schematically showing the structure of an embodiment of an ink jet head of the present invention.

Although only the structure for one head is shown in FIG. 1, in practice, a head having such a structure is
A multi-nozzle inkjet head is configured by arranging a plurality of dimensions or by arranging a plurality in a matrix as shown in FIG.

The ink jet head of this embodiment is
This is a thermal distortion drive type recording head used in a general inkjet printer, and includes a nozzle plate 1 and a silicon substrate 2, as shown in FIG. The nozzle plate 1 and the silicon substrate 2 are bonded with an adhesive.

Nozzles 11 for ejecting ink droplets are formed on the nozzle plate 1.

The silicon substrate 2 is provided with an ink chamber 21 having a side wall 21a, an ink channel 22, and an ink supply port 23 for guiding ink to the ink channel 22.

The ink chamber 21 is provided at a position corresponding to each nozzle 11 of the nozzle plate 1, and the center of the nozzle 11 and the center of the ink chamber 21 are substantially coincident with each other.
The ink chamber 21, the ink flow path 22, and the ink supply port 23 are formed by anisotropic etching of silicon, for example.

A deformable diaphragm 3 is provided on the back surface side (end portion of the side wall 21a) of the ink chamber 21. The periphery of the diaphragm 3 is a side wall 21a of the ink chamber 21.
It is fixed to. The diaphragm 3 is composed of a Ni film and is an electrothermal conversion element that causes buckling deformation due to thermal expansion caused by flowing an electric current.

The diaphragm 3 is provided with an electrode pad 6 for supplying a current. The electrode pad 6 of the diaphragm 3 is connected to the electrode pad 7 of a wiring pattern (not shown) formed on the silicon substrate 2 by wire bonding 8.

An alignment mark (through hole) 25 is formed on the silicon substrate 2. An alignment mark 12 is also formed on the nozzle plate 1. These alignment marks 25 and 12 are used for aligning each part when manufacturing the inkjet head.

In this embodiment, the leakage of current from the diaphragm 3 to the side wall 21a is prevented, and
In order to prevent the heat generated in the diaphragm 3 from being transferred to the side wall 21a, an insulating film 5 made of silicon dioxide or the like is provided between the diaphragm 3 and the side wall 21a. Further, a Ta film 4 is provided between the diaphragm 3 and the insulating film 5 in order to increase the adhesion between the diaphragm 3 and the insulating film 5.

Further, a separation groove 24 is formed at the boundary of the ink chamber 21. The separation groove 24 is formed by, for example, anisotropic etching of silicon.

Next, the operation of the ink jet head having the structure shown in FIG. 1 will be described with reference to FIG.

First, when a predetermined current of metal is applied to the diaphragm 3 from the power source 9 through the wire bonding 8,
Joule heat is generated in the diaphragm 3, and the generated heat causes the diaphragm 3 to expand. However, since the periphery of the diaphragm 3 is fixed to the side wall 21a of the ink chamber 21, it suddenly buckles and deforms toward the ink chamber 21 as shown in FIG. 3B. When the diaphragm 3 buckles and deforms in this way, the pressure in the ink chamber 21 rapidly increases, and ink droplets are ejected from the nozzle 11.

Next, when the current is cut off, the diaphragm 3
Returns to the original state, as shown in FIG. In addition,
In order to simplify the description, only the deformable diaphragm 3 is shown in FIG. 3, and the insulating film 5 and the Ta film 4 in FIG. 1 are omitted.

Here, in the ink jet head having the structure shown in FIG. 1, since the insulating film 5 having a low thermal conductivity is provided between the diaphragm 3 and the side wall 21a, the insulating film 5 acts as a heat insulating material. As a result of the reduced heat capacity of the diaphragm 3, it is possible to realize an inkjet head with high efficiency in heating the diaphragm 3.

The insulating film 5 is the thermal oxide film (SiO ₂ ) 1 formed on the back surface of the silicon substrate in the manufacturing process.
It may be 03 (see FIG. 6).

Next, the deformation of the diaphragm will be described with reference to FIG.

FIG. 4 is a diagram showing a temperature curve in the heating / cooling process of the metal with respect to the pulse current supplied to the metal. As is clear from FIG. 4, when the diaphragm is made of metal, the curve during heating is steeper than that during cooling, so the deformation speed of the diaphragm is higher during heating. Therefore, it is better to reduce the volume of the ink chamber during heating than to reduce the volume of the ink chamber during cooling.
Ink droplets can be ejected vigorously.

However, the present invention is not limited to this, and the diaphragm is deformed on the side opposite to the ink chamber (the direction away from the ink chamber) during heating, and when the diaphragm returns to the initial state during cooling, the ink chamber is restored. The ink droplet may be ejected by the pressure generated at the time.

As described above, according to the ink jet head of this embodiment, the ink droplets are ejected from the nozzle 11 by the pressure generated by the volume change of the ink chamber 21 due to the buckling deformation of the diaphragm 3, so that the conventional ink jet head is used. Compared with the structure supported by a cantilever beam or a double-supported beam, pressure does not leak, and ink droplets can be ejected efficiently.

Although the ink chamber 21 vibrates due to the buckling deformation of the diaphragm 3, as shown in FIGS.
Since each ink chamber 21 is separated by the separation groove 24, vibration is not transmitted to the adjacent ink chamber 21 and crosstalk can be reduced.

FIG. 5 is a schematic sectional view of another embodiment of the ink jet head of the present invention.

The ink jet head shown in FIG.
In addition to the above configuration, the back surface of the diaphragm 3 (the ink chamber 21
Is characterized in that another insulating film 10 such as silicon dioxide or glass having a thermal expansion coefficient smaller than that of metal is arranged on the surface opposite to the above.

The thickness of each constituent material in this case is, for example,
The insulating film 5 between the diaphragm 3 and the ink chamber 21 is 50
0 Å, Ta film 4 is 400 Å, diaphragm 3 is 2 μm, and another insulating film 10 is 2 μm.

With such a thickness, the insulating film 5 and T
Since the thickness of the a film 4 is negligibly smaller than the thickness of the insulating film 10 different from the diaphragm 3, deformation due to thermal expansion may be considered in the insulating film 10 different from the diaphragm 3.

In the structure of FIG. 5, by heating the diaphragm 3 by energization, the insulating film 10 different from the diaphragm 3 is heated.
And expand. At this time, the diaphragm 3 (Ni film) has a larger thermal expansion coefficient than the other insulating film 10 (for example, a silicon dioxide film), so that the diaphragm 3 expands more than the other insulating film 10. Therefore, the diaphragm 3 is more rapidly buckled and deformed toward the ink chamber 21 side.

Here, in the above embodiment, the structure is such that the electric current is passed through the diaphragm 3 made of metal (conductor) to generate heat, but the present invention is not limited to this, and the diaphragm made of an insulating material is used. It is also possible to form a heater on the above and generate heat by energizing the heater to buckle and deform the diaphragm.

Next, a method for manufacturing the ink jet head shown in FIG. 1 will be described with reference to FIGS. 6 and 7.

FIG. 6A: Thermal oxide film 1 on both sides as a substrate
The silicon substrate 101 on which 02 and 103 are formed is used.

FIG. 6B: On the thermal oxide film 103 on the back surface of the silicon substrate 101, Ta is deposited by, for example, 1 by sputtering.
A film with a thickness of 00Å is formed, and then Ni is used as the plating base
Is deposited to a thickness of 200Å, for example.

Next, the silicon substrate 101 is dipped in a bath of nickel sulfamate, and the underlying Ni is used as an electrode to carry out electrolytic plating under conditions of a current density of 20 mA / cm ² , pH 4.4 and a temperature of 50 ° C. (thickness). : For example, 5 μm). At this time,
As shown in the stress characteristics (relationship between stress and current density) of the plated film shown in FIG. 8, the stress of the Ni plated film by plating at the current density of 20 mA / cm ² is zero.

After the Ni plating is completed, a photoresist (not shown) is applied on the Ni plated film to form the diaphragm 3
Patterning (exposure and development). Next, Ni
The plating film and the Ta film (underlying Ni) are processed by etching to obtain the diaphragm 3 and the Ta film 4, and then the photoresist is peeled off.

The Ta film 4 is formed to increase the adhesion between the thermal oxide film 103 (insulating film 5) on the back surface of the silicon substrate 101 and the diaphragm 3.

FIG. 6C: After applying a photoresist (not shown) on the thermal oxide film 103, patterning (exposure / development) is performed in a shape corresponding to the alignment mark to be formed. Next, the thermal oxide film 103 is dry-etched by RIE (reactive ion etching) using CF ₄ gas, and then the photoresist is removed.

FIG. 6D: The silicon substrate 101 in the state of FIG. 6C is immersed in a KOH solution for anisotropic etching. By this anisotropic etching, a tapered through hole 104 as shown in the drawing is formed. This through hole 104
The narrow hole on the surface of the is an alignment mark 25, which can be used for alignment in the subsequent processes.

The thermal oxide film 1 is formed on the surface of the through hole 104.
02 remains, but the through-hole 104 has the silicon substrate 10
Since it penetrates through No. 1, the alignment mark 25 can be recognized from the front surface side (the thermal oxide film 102 side) of the silicon substrate 101.

Further, the through hole 104 can be used as the ink supply port 23 for guiding the ink to the ink flow path 22.

FIG. 6E: A photoresist (not shown) is applied on the thermal oxide film 102 on the surface of the silicon substrate 101, and patterning (exposure) is performed in a shape corresponding to the ink chamber 21 and the ink flow path 22 to be formed. ·develop. At this time, the photomask used is the alignment mark 25.
If the alignment is performed with respect to the silicon substrate 101 on the basis of, the alignment can be performed with high accuracy.

Next, a thermal oxide film 102 is formed by using CF ₄ gas.
Is dry-etched by RIE, and then the photoresist is removed.

FIG. 6F: The silicon substrate 101 in the state of FIG. 6E is immersed in a KOH solution to perform anisotropic etching. By this anisotropic etching, as shown in the figure, a tapered groove 105 (ink chamber 21) is formed. At the same time, the ink flow path 22 is formed.

In the above anisotropic etching of the silicon substrate 101, if a silicon substrate having a plane orientation (100) is used, the surface of the taper portion of the groove formed is (11).
1) surface, the relationship between the depth d of the groove and the width x of the pattern is 2d = xtan θ, and the depth of the groove can be freely designed according to the width of the pattern. Where (11
The angle θ between the 1) plane and the (100) plane is 54.7 degrees.

FIG. 7G: A shape corresponding to the thickness of the side wall 2a (partition wall) of the ink chamber 21 to be formed by applying a photoresist (not shown) on the thermal oxide film 103 on the back surface of the silicon substrate 101. Patterning (exposure and development). At this time, if the photomask used is aligned with the alignment mark 25 or an alignment mark (not shown) formed on the back surface of the silicon substrate 101 when the alignment mark 25 is formed,
High-precision alignment is possible.

Next, a thermal oxide film 103 is formed by using CF ₄ gas.
Is dry-etched by RIE (reactive ion etching), and then the photoresist is removed.

7H: The silicon substrate 101 in the state of (G) is immersed in a KOH solution for anisotropic etching. By this anisotropic etching, the tapered groove 106 (separation groove 24) as shown in the drawing is formed. At this time, the side wall 21 of the ink chamber 21 is formed by the groove 106 formed.
The thickness of a is determined. Further, this process (anisotropic etching of the groove 106) can separate the adjacent ink chamber, as shown in FIG. 2, although not shown in FIG.

FIG. 7I: Through the above steps, the ink chamber 21, the ink flow path 22, the ink supply port 23, the separation groove 2 are formed.
4 and the silicon substrate 2 on which the alignment mark 25 is formed, and the nozzle plate 12 on which the plurality of nozzles 11 and the alignment mark 12 are formed in another process.
By aligning the two alignment marks 25 and 12 with each other by using an adhesive (not shown),
The inkjet head is completed.

Finally, as shown in FIG. 1, an electrode pad (bump) is formed on the diaphragm 3 which is an electrothermal converting element.
6 is formed, electrode pads (bumps) 7 are formed on a wiring pattern (not shown) formed on the silicon substrate 2, and these electrode pads 6, 7 are connected by a simple method such as wire bonding 8. Then, the electric current can be supplied to the diaphragm 3.

The method of using the hole at the tip of the through hole 104 produced by the process of FIG. 6D as the alignment mark 25 at the time of adhering the nozzle plate is as shown in FIG.
It is not limited to the diaphragm type ink jet head as shown in FIG.

For example, as shown in FIG. 9, the ink chamber 22
1 has an electrothermal converter 223 disposed therein, and a current is caused to flow through the electrothermal converter 223 to cause film boiling in the ink and eject ink droplets from the nozzle 211, which is a so-called bubble jet (registered trademark) system. It can also be applied to an inkjet head. Also, as shown in FIG. 10, the ink chamber 321 is deformed by the deformation of the laminated piezoelectric material 323.
Ink drops are generated by changing the pressure of the nozzle 31.
It can also be applied to a piezoelectric ink jet head ejecting from 1.

[0073]

As described above, according to the ink jet head of the present invention, the change in the volume of the ink chamber due to the deformation of the diaphragm is utilized for the ejection of the ink droplets. Ink droplets can be efficiently ejected without leaking pressure as compared with the structure in which the beam is agitated. Further, since each pressure chamber is separated by the groove, vibration is not transmitted to the adjacent ink chamber,
Crosstalk can be reduced.

According to the method of manufacturing an ink jet head of the present invention, at least one through hole is formed in the substrate forming the ink chamber, and the through hole is used as an alignment mark when the nozzle plate is bonded to the substrate. Therefore, the substrate having the ink chambers and the nozzle plate having the nozzles can be aligned easily and accurately. Therefore, a low-cost inkjet head with stable performance can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view (A) and a plan view (B) schematically showing an embodiment of an inkjet head of the present invention.

FIG. 2 is a perspective view schematically showing an arrangement of ink chambers.

FIG. 3 is an operation explanatory diagram of the embodiment of the inkjet head of the present invention.

[Fig. 4] Heating of metal when pulse current is applied to the metal
It is a figure which shows the temperature curve of a cooling process.

FIG. 5 is a cross-sectional view schematically showing another embodiment of the inkjet head of the present invention.

FIG. 6 is an explanatory diagram of a method of manufacturing the inkjet head of FIG.

FIG. 7 is an explanatory diagram of the same manufacturing method.

FIG. 8: Stress characteristics of plated film (relationship between stress and current density)
It is a graph which shows.

FIG. 9 is a cross-sectional view schematically showing an example of an inkjet head (bubble jet method) to which the manufacturing method of the present invention can be applied.

FIG. 10 is a cross-sectional view schematically showing an example of an inkjet head (piezoelectric method) to which the manufacturing method of the present invention can be applied.

[Explanation of symbols]

1 nozzle plate 11 nozzles 12 Alignment mark 2 Silicon substrate 21 ink chamber 21a side wall 22 ink flow path 23 Ink supply port 24 separation groove 3 Diaphragm (Ni film) 4 Ta film 5 insulating film 6 electrode pads 7 electrode pad 8 wire bonding 9 power supplies 10 Another insulating film 101 Silicon substrate 102,103 thermal oxide film 104 through hole

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Claims (15)

[Claims] 1. A nozzle plate having a plurality of nozzles for ejecting ink droplets, a plurality of ink chambers formed corresponding to the nozzles, an ink flow path for supplying ink to each ink chamber, and an ink. In a multi-nozzle inkjet head that has an ink supply port that guides ink to the flow path, a diaphragm is formed in each ink chamber, and ink drops are generated by the pressure generated by the volume change of the ink chamber due to the buckling deformation of the diaphragm. An inkjet head characterized in that it is configured to eject from a nozzle and a groove is provided at a boundary of each ink chamber. 2. The diaphragm is configured to buckle and deform due to thermal expansion.
The described inkjet head. 3. The ink jet head according to claim 1, wherein the diaphragm is made of metal. 4. The ink jet head according to claim 3, wherein the metal forming the diaphragm is an electrothermal conversion element. 5. The inkjet according to claim 1, wherein the diaphragm is provided with a material having a thermal expansion coefficient smaller than that of the diaphragm on a surface opposite to the ink chamber. head. 6. The ink jet head according to claim 1, wherein the electrothermal conversion element forming the diaphragm is connected to a wiring pattern formed on the substrate by wire bonding. . 7. A nozzle plate having a plurality of nozzles for ejecting ink droplets, a plurality of ink chambers formed corresponding to the nozzles, an ink flow path for supplying ink to each ink chamber, and an ink. A multi-nozzle inkjet head having an ink supply port for introducing ink to a flow path, configured to eject an ink droplet from a nozzle according to a pressure change in the ink chamber, and having a groove provided at a boundary between the ink chambers. In the step of manufacturing the inkjet head, at least one through hole is formed in the substrate forming the ink chamber, and the through hole is used as an alignment mark when the nozzle plate is bonded to the substrate. Method. 8. The method of manufacturing an ink jet head according to claim 7, wherein the through hole is formed in a step of forming the ink supply port. 9. A nozzle plate having a plurality of nozzles for ejecting ink droplets, a plurality of ink chambers formed corresponding to the nozzles, an ink flow path for supplying ink to each ink chamber, and an ink. An ink supply port that guides ink to the flow path is provided, and a diaphragm is formed in each ink chamber, and ink droplets are ejected from the nozzle by the pressure generated by the volume change of the ink chamber due to the buckling deformation of the diaphragm. In the process of manufacturing a multi-nozzle inkjet head having the above-mentioned configuration and grooves provided at the boundaries of the ink chambers, at least one through hole is formed in the substrate forming the ink chamber, and the through hole is formed. A method for manufacturing an inkjet head, which is used as an alignment mark when a nozzle plate is bonded to a substrate. 10. The method of manufacturing an ink jet head according to claim 9, wherein the ink chamber is formed by anisotropic etching of silicon. 11. The method for manufacturing an inkjet head according to claim 9, wherein the ink flow path is formed by anisotropic etching of silicon. 12. The ink chamber, the ink flow path, and the ink supply port are formed by anisotropic etching of one silicon substrate.
5. The method for manufacturing an inkjet head according to any one of 1. 13. The method of manufacturing an ink jet head according to claim 9, wherein the ink chamber and the ink flow path are formed by aligning with the through hole as a reference. 14. The diaphragm is formed of metal, and a side wall of the ink chamber other than the diaphragm is formed of silicon, and a film having a small thermal conductivity is provided at a boundary between the silicon and the diaphragm formed of metal. The method for manufacturing an inkjet head according to any one of claims 9 to 13, wherein: 15. The method of manufacturing an inkjet head according to claim 9, wherein a Ta film is provided on the base of the diaphragm.