JPH0834117A - Ink jet head, using method and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide an ink jet head which has a response property excellent for heating and cooling, and is suitable for high speed printing. CONSTITUTION:A nozzle plate 111 has a nozzle orifice 111a. At a predetermined distance from the nozzle orifice 111a, an ink supply opening 107 having an opposite opening end is provided on a base plate 105. A central part of a buckling structure 101 is positioned in between the nozzle orifice 111a and the opening of the ink supply opening 107, and both ends of the structure are supported by at least the base plate 105. A compression means gives compressive stress to the inside of the buckling structure 101 by heating. The base plate 105 has a thickness of 20mum or more and the ink supply opening 107 penetrates the base plate 105 in the thickness direction. The opening area of the ink supply opening 107 is 900mum<2> or less at its opening end. The buckling structure 101 is buckled by the compressive stress given by the compression means and the central part of the buckling structure 101 is deformed toward the nozzle orifice 111a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet head, a method of using the same and a method of manufacturing the same. More specifically, the present invention relates to an inkjet head that applies pressure to an ink liquid filled inside to eject the ink liquid from the inside to the outside, a method of using the same, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, an ink jet method is known in which a recording liquid is discharged and ejected to perform recording. This method has various advantages such as low noise and relatively high-speed printing, downsizing of the apparatus, and easy color recording. In such an inkjet head recording method, recording is performed using inkjet recording heads based on various droplet ejection principles.

Several types of ink jet heads have hitherto been used. For example, there are those using a piezoelectric element and those using a bubble jet method.

FIG. 24 is a main sectional view schematically showing the structure of a conventional ink jet head using a piezoelectric element. Referring to FIG. 24, this inkjet head 31
Reference numeral 0 has a container 305 and a laminated piezoelectric element 304.

The container 305 has a space 305a, a nozzle orifice 305b, and an ink supply port 305d. The space 305 a is provided inside the container 305 and can fill the ink 80. Also this space 3
The ink 80 can be supplied to 05a from the ink supply port 305d. A nozzle orifice 305b is provided on the wall portion of the container 305 so that the space 305a communicates with the external space of the container 305.

The laminated piezoelectric element 304 is provided in the space 3 of the container.
A plurality of piezoelectric elements 30 are provided inside 05a.
1 and a pair of electrodes 303. A plurality of piezoelectric elements 301 are laminated, and a pair of electrodes 303 are alternately arranged so as to be sandwiched between the piezoelectric elements 301. Thereby, a voltage is effectively applied to each piezoelectric element 301. Also, a pair of electrodes 30
A power source 307 is connected to the switch 3, and the switch is turned on.
・ Voltage application is switched by switching OFF.

In the operation of the ink jet head 310, a switch is turned on to apply a voltage to the pair of electrodes 303. As a result, each piezoelectric element 301 extends in the longitudinal direction (direction of arrow A ₁ ) and ink 8
Pressure is applied to 0 in the directions of arrows A ₂ and A ₃ , for example.
In particular, the pressure in the direction of the arrow A ₂ causes the ink 80 to be ejected from the nozzle orifice 305b to the outside.
a is formed. Printing is performed on the print surface by the ejected or ejected ink liquid 80a.

FIG. 25 is an exploded perspective view schematically showing the structure of a bubble jet type ink jet head.
Referring to FIG. 25, this inkjet head 410
Has a heater unit 404 and a nozzle unit 405.

The heater section 404 has a heater 401, an electrode 403, and a substrate 411. That is, the electrode 403 and the heater 401 connected to the electrode 403 are formed on the surface of the substrate 411.

The nozzle portion 405 has a nozzle 405a, a nozzle orifice 405b, and an ink supply port 405c. A plurality of nozzles 405a are provided corresponding to the heater 401, and a nozzle orifice 405b is provided corresponding to each nozzle 405a. Further, an ink supply port 4 for supplying ink to each nozzle 405a
05c is provided.

The operating principle of this bubble jet type ink jet head is as follows.

FIGS. 26A to 26E are schematic cross-sectional views of nozzles showing a droplet forming process of a bubble jet type ink jet head in process order.

First, referring to FIG. 26A, an electric current is passed through the heater 401 by energizing an electrode (not shown). As a result, the heater 401 is rapidly heated, and the nuclear bubble 81a is generated on the surface of the heater 401.

Referring to FIG. 26B, since the heater 401 is rapidly heated, the ink 80 reaches the heating limit before the preexisting foam nuclei are activated. This allows
Nuclear bubbles 81a on the surface of the heater 401 are united to obtain a film bubble 81b.

Referring to FIG. 26 (c), the heater 4 is further added.
By heating 01, the film bubble 81b adiabatically expands and grows. The ink 80 receives a pressure corresponding to the volume of growth of the film bubble 81b. This pressure causes the ink 8
0 is pushed out of the orifice 405b. Membrane bubble 81b
The heating of the heater 401 is stopped at the time when the maximum value becomes.

Referring to FIG. 26D, the heating of the heater 401 is stopped, so that the film bubble 81b is absorbed by the surrounding ink 80. Thereby, the membrane bubble 81b
Of the ink is contracted, and the ink 80 is sucked into the nozzle 405a. The suction of the ink 80 causes the orifice 405.
The ink 80a extruded outside b tends to form an ink drop.

Referring to FIG. 26 (e), the film bubble 8 is further added.
The ink droplet 80a is formed when the volume of 1b contracts or the film bubble 81b disappears. This ink liquid 8
Printing or printing is performed on the print surface by the ejection or ejection of 0a.

Further, Japanese Patent Laid-Open No. 30543/1990 discloses an ink jet head which forms an ink droplet by using the displacement of a driving body driven by a temperature change shown in FIG.

Referring to FIG. 27, the ink jet head 510 mainly has a pressure generating member 501, a nozzle plate 511, a spacer 513a, and a housing 515. The nozzle plate 511 and the housing 515 are joined together with the spacer 513a interposed therebetween, thereby forming a space that can fill the ink 80. The pressure generating member 501 is located in this space, and both ends of the pressure generating member 501 are fixed to the spacer 513a with the pattern electrodes 513b interposed therebetween. A nozzle orifice 511a is provided in the nozzle plate 511 so as to face the pressure generating member 501.

In the operation of the ink jet head 510, an electric current is passed through the pattern electrode 513b in the longitudinal direction of the pressure generating member 501. As a result, the temperature of the pressure generating member 501 rises, and thermal strain is generated and displaced.
Due to this displacement, ink droplets are ejected or fly from the nozzle orifice 511a.

[0021]

However, the above-mentioned prior art has the following problems.

First, in the inkjet head 310 shown in FIG. 24, in order to increase the amount of deformation of the piezoelectric element 301, each piezoelectric element 301 must be formed with a large film thickness. Therefore, the piezoelectric element 301 cannot be formed by the thin film forming method, and the piezoelectric element is mechanically processed to form the head. Therefore, the size of the piezoelectric element 304 increases, and the size of the ink chamber 305a that houses it also increases. As a result, in the multi-nozzle head in which the nozzles 305b are integrated, there is a problem that the interval between the nozzles 305b for ejecting ink cannot be reduced.

Further, the opening area S of the ink supply port 305d is
₀ was set relatively high. Therefore, the ink 8
There is a problem that 0 easily flows back in the direction opposite to the nozzle orifice 305b along the direction of the arrow A ₃ and the discharge efficiency is poor.

The bubble-jet type a shown in FIG.
In the ink jet head 410, as shown in FIGS.
In the process shown in, film boiling is performed to obtain clean air bubbles 81b.
It is necessary to cause a rising phenomenon. For this, the heater
It is necessary to rapidly heat 401. Specifically,
C.80 must be heated to about 300.degree.
Therefore, the heater 401 is heated up to around 1000 ° C.
Also, in order to realize high-speed printing, the heater 401 has a short
The heating and cooling must be repeated in time. this
If heating and cooling to high temperature are repeated,
H with excellent heat resistance _FourB_FourAnd other materials for the heater 401
However, thermal fatigue occurs in the heater 401. This
Sea urchin bubble jet inkjet head 410
Then, the heater 401 is easily deteriorated, and
There was a problem that the life of the head was shortened.

Inkjet head 5 shown in FIG. 27
In 10, the compressive force generating member 501 is displaced by heating,
Then, it is cooled and returns to its original shape. That is, in order to continuously repeat the displacement and the return of the compressive force generating member 501, the heating and cooling of the compressive force generating member 501 are repeated. When the compressive force generating member 501 does not immediately radiate heat during this cooling, the compressive force generating member 501
Is hard to be cooled, and the compressive force generating member 5 by heating and cooling is
The response characteristic of the displacement of 01 becomes worse. Therefore, there is a problem that it is not suitable for high-speed printing.

Further, the central portion of the compression force generating member 501 is displaced toward the nozzle orifice 511 side, so that ink droplets are ejected from the nozzle orifice 511a. However, in the inkjet head 510, the central portion of the compressive force generating member 501 may be displaced to the side opposite to the nozzle orifice 511a. In such a case, it may happen that the appropriate ink droplets are not ejected. Therefore,
There was a problem that accurate printing could not be performed.

As described above, it is an object of the present invention to provide an ink jet head having good response characteristics by heating and cooling and suitable for high speed printing.

Another object of the present invention is to prevent backflow of ink to the ink supply port side and improve the efficiency of ink ejection.

Still another object of the present invention is to realize proper ejection of ink liquid and perform accurate printing.

Still another object of the present invention is to provide an ink jet head which has a long life and can obtain a large ejection force while maintaining a small size.

[0031]

According to another aspect of the present invention, there is provided an ink jet head which applies pressure to an ink liquid filled therein to eject the ink liquid from the inside to the outside. It has a substrate, a buckling structure, and a compression means. The nozzle plate has a nozzle orifice. The substrate is provided with an ink supply port having an opening end facing the nozzle orifice at a predetermined distance. The buckling structure body is provided such that its central portion is located between the nozzle orifice and the opening end of the ink supply port, and both end portions are supported by at least the substrate. The compressing means plays a role of applying compressive stress to the inside of the buckling structure body by heating. The buckling structure is buckled by the compressive stress applied by the compressing means, and the central portion of the buckling structure is deformed toward the nozzle orifice side. The opening area of the ink supply port is 900 μm ² or less at the opening end. The substrate has a thickness of 20 μm or less, and the ink supply port extends in the thickness direction of the substrate and penetrates the substrate.

An ink jet head according to a second aspect is an ink jet head that applies pressure to an ink liquid filled inside and ejects the ink liquid from the inside to the outside, and includes a nozzle plate, a substrate, and a buckling structure. It has a body and a compression means. The nozzle plate has a nozzle orifice. The substrate is provided with an ink supply port having an opening end facing the nozzle orifice at a predetermined distance. The buckling structure body is provided such that its central portion is located between the nozzle orifice and the opening of the ink supply port, and both end portions are supported by at least the substrate. The compressing means plays a role of applying compressive stress to the inside of the buckling structure body by heating. The buckling structure is buckled by the compressive stress applied by the compressing means, and the central portion of the buckling structure is deformed toward the nozzle orifice side. The opening area of the ink supply port is 900 μm ² or less at the opening end. The thickness of the substrate is 20 μm or more, and the ink supply port extends in the thickness direction of the substrate and penetrates the substrate. The distance between the buckling structure and the substrate is 5 μm or less. Substrate material is 7
It contains a material having a thermal conductivity of 0 W · m ⁻¹ · K ⁻¹ or more.

In the ink jet head according to the third aspect, it is desirable that the ink supply port penetrates the substrate while maintaining a sectional area substantially the same as the opening area at the opening end.

In the ink jet head according to the fourth aspect, it is desirable that the opening diameter of the ink supply port is 1/3 or less of the length of the buckling portion of the buckling structure.

In the ink jet head according to the present invention, the buckling structure has a front surface facing the nozzle plate and a back surface located behind the front surface, and both end portions of the buckling structure body on the back surface. Is preferably supported on the substrate.

According to a sixth aspect of the invention, in which the ink jet head is used, pressure is applied to the ink liquid filled inside,
A method of using an inkjet head for ejecting an ink liquid from the inside to the outside, the inkjet head including a nozzle plate, a substrate, a buckling structure, and a compression unit. The nozzle plate has a nozzle orifice. The substrate is provided with an ink supply port having an opening end facing the nozzle orifice at a predetermined distance. The buckling structure body is provided such that its central portion is located between the nozzle orifice and the opening of the ink supply port, and both end portions are supported by at least the substrate.
The compressing means plays a role of applying compressive stress to the inside of the buckling structure body by heating. The buckling structure is buckled by the compressive stress applied by the compressing means, and the central portion of the buckling structure is deformed toward the nozzle orifice side. The thickness of the substrate is 2
It is at least 00 μm. The opening area of the ink supply port is 90 μm ² or less at the opening end, and the ink supply port extends in the thickness direction of the substrate and penetrates the substrate while maintaining the opening area at the opening end. The buckling structure is driven under the condition that the power consumption per unit volume of the buckling structure is 4 × 10 ¹³ W / m ³ or more.

According to a seventh aspect of the present invention, there is provided an ink jet head manufacturing method, wherein pressure is applied to the ink liquid filled inside,
A method for manufacturing an inkjet head in which an ink liquid is ejected from the inside to the outside, which includes the following steps.

First, the substrate is prepared to have a thickness of 20 μm or more. The both ends are supported by the main surface of the substrate, the buckling structure is formed so that the central portion is separated from the main surface of the substrate by a predetermined distance, and the central portion of the buckling structure penetrates the substrate in the thickness direction. Is formed so that the opening area at the opening end is 900 μm ² or less. Then, a nozzle plate having a nozzle orifice is formed. Then, the nozzle plate is bonded to the substrate so that the central portion of the buckling structure is located between the nozzle orifice and the opening end of the ink supply port.

[0039]

In the ink jet head according to the first and second aspects of the invention, the ejection speed of the ink droplet is improved by making the path of the ink supply port long and reducing the opening area. In particular, the path length of the ink supply port is 20 μm or more, and the opening area of the ink supply port is 900 μm over the path.
Since it is m ² or less, an ink ejection speed of 2 m / s or more can be realized. Therefore, the design of the gap between the head and the printing paper is facilitated and the printing quality is improved.

The buckling structure is displaced in the thickness direction due to buckling. In this deformation due to buckling, even if the displacement amount in the plane direction is small, the small displacement amount can be converted into a large displacement amount in the thickness direction. Therefore, it is possible to obtain a large displacement amount without increasing the size of the buckling structure, and thereby a large ejection force can be obtained. Further, in order to buckle the buckling structure, the buckling structure may be fixed at both ends in the plane direction, and the structure is very simple. From this point as well, it is easy to reduce the size. Therefore, it is possible to obtain an ink jet head that can obtain a large ejection force while maintaining a small size.

Further, when buckling is performed by heating, for example, it is necessary to heat the buckling structure. However, in this case, it is not necessary to heat the buckling structure to a temperature at which the ink itself is vaporized. That is, it is sufficient to heat the material to a temperature according to the coefficient of thermal expansion of the material. Therefore, it is not necessary to heat the buckling structure to a high temperature unlike the heater of a bubble jet type inkjet head. Therefore, thermal fatigue due to repeated heating and cooling at such a high temperature is less likely to occur, the buckling structure body is less deteriorated, and its life is relatively long. Moreover, since the required amount of heat may be small, the power consumption can be small.

Particularly, in the ink jet head according to the second aspect, the distance between the buckling structure and the substrate, the opening area at the opening end of the ink supply port, and the material of the substrate are limited to predetermined values and materials. For this reason, the heat dissipation of the heated buckling structure is improved, and the responsiveness of the displacement of the buckling structure to heating / cooling is improved. Therefore, the frequency response of the buckling structure can be 2.5 kHz or more.

When the values such as the distance between the buckling structure and the substrate and the materials are other than those mentioned above, the frequency response of the buckling structure becomes smaller than 2.5 kHz, and the printing speed of the printer becomes slow. Not suitable for high speed printing.

In the ink jet head according to the fourth aspect, since the opening diameter of the ink supply port is 1/3 or less of the length of the buckling portion of the buckling structure, the area where the buckling structure and the substrate face each other. Will be set larger. Therefore, the heat of the heated buckling structure is more easily released through the substrate, and the heat dissipation is further improved.

In the ink jet head according to the fifth aspect, both ends of the buckling structure are supported by the substrate on the back surface of the buckling structure facing the nozzle orifice.
Therefore, the central portion of the buckling structure is always displaced toward the nozzle plate due to the action of the moment. Therefore, the driving direction of the buckling structure can be controlled with a simple structure.

In the method of using the inkjet head according to the sixth aspect, the buckling structure is driven under the condition that the power consumption per unit volume of the buckling structure is 4 × 10 ¹³ W / m ³ or more. A sufficient ink ejection speed can be obtained. In particular, if the path length of the ink supply port is set to 20 μm or more and the opening area of the ink supply port is set to 900 μm ² or less over the path, the ink ejection speed of 2 m / s or more can be realized. Therefore, the design of the gap between the head and the printing paper is facilitated and the printing quality is improved.

The ink jet head manufacturing method according to claim 7 has the effects that the buckling structure is excellent in heat dissipation, a large ejection force can be obtained with a small size, and the life is long. The head is obtained.

Further, since it can be formed by using the photolithography technique, the dimensional accuracy of the pattern is high,
The mass production effect is great, and high integration and cost reduction are possible.

[0049]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

[Principle of Recording] First, the principle of recording by the ink jet head of the present invention will be described.

FIG. 1 is a main sectional view schematically showing the construction of an ink jet head of the present invention in a standby state. Further, FIG. 2 is a main cross-sectional view showing a schematic configuration in an operating state of the inkjet head of the present invention.

First, referring to FIG. 1, an ink jet head 50 of the present invention comprises a buckling structure 1, a substrate 5, an insulating member 9, a nozzle plate 11, a spacer 13, a housing 15, and a housing 15. It has a power supply 17.

Both ends of the buckling structure 1 are fixed to one surface of the substrate 5 with an insulating member 9 interposed. The central portion of the buckling structure body 1 is separated from the insulating member 9 by a predetermined distance. Further, both ends of the buckling structure 1 are electrodes 1a and 1b, and a voltage can be applied to the electrodes 1a by a power supply 17. The electrode 1b is grounded. An ink supply port 7 having a circular or square cross section is formed so as to penetrate the substrate 5 and the insulating member 9.

A nozzle plate 11 is attached to the side of the substrate 5 to which the buckling structure 1 is attached with a spacer 13 interposed. A nozzle orifice 11a is formed so as to penetrate the nozzle plate 11. The central portion of the buckling structure 1 is located between the nozzle orifice 11a and the ink supply port 7. A housing 15 is attached to the opposite side of the substrate 5 to which the buckling structure 1 is attached.
An ink flow path 15a for guiding ink is formed in the housing 15.

In the operation of this ink jet head 50
First, the ink 80 is supplied through the ink flow path 15a.
And the buckling structure 1 is immersed in the ink 80.
Become. After that, the power source 17 is applied to the electrode 1a of the buckling structure body 1.
Voltage is applied. As a result, the buckling structure 1 is
A current flows between the pole portions 1a and 1b, so that the buckling structure 1 does not
It is heated by anti-heat generation, and is heated in the longitudinal direction (arrow D₀Direction)
Try to. However, in the longitudinal direction of the buckling structure 1.
Since both ends are fixed to the substrate 5, the buckling structure 1
It cannot extend in its longitudinal direction. Therefore buckling
The structure 1 has an arrow F as its reaction force.₀Compressive force P in the direction₀
Is given and accumulated. This compression force P ₀Buckled structure
Buckling load P of 1_CBuckling structure 1 is shown in FIG.
Buckling deformation occurs, as shown.

Referring to FIG. 2, due to the buckling deformation of buckling structure 1, the central portion of buckling structure 1 is nozzle plate 11
Displace to the side. Therefore, the ink 80 is extruded to the outside through the nozzle orifice 11a, the ink droplet 80a is formed outside the inkjet head 50, and is ejected to the outside. By the ejection of the ink droplet 80a, printing (recording) is performed on the print surface.

[First Embodiment] FIG. 3 is an exploded perspective view schematically showing the structure of an ink jet head according to the first embodiment of the present invention. Moreover, FIG. 4 and FIG.
It is a schematic cross-sectional view taken along a schematic cross-sectional view and a line Y-Y along ₁ -X ₁ line.

Mainly referring to FIG. 3, the ink jet head 150 according to the first embodiment of the present invention includes a pressure generator 110, a nozzle plate 111, and a spacer 113.
And a housing 115.

The nozzle plate 111 is made of, for example, a glass or plastic sheet having a thickness of 0.2 mm. In the nozzle plate 111, a plurality of nozzle orifices 111a penetrating the nozzle plate 111 and arranged in a certain direction are formed in a conical shape or a funnel shape.

The spacer 113 is made of an insulating material such as polyimide. Further, the spacer 113 is provided with a plurality of openings 113a penetrating the spacer 113 and forming a pressure chamber. The plurality of openings 113a are provided corresponding to the nozzle orifice 111a.

The pressure generator 110 comprises the buckling structure body 101.
And a substrate 105 and an insulating member 109.
The substrate 105 is made of, for example, silicon or glass. In addition, the substrate 105
There are provided a plurality of elongated ink supply ports 107 that pass through the nozzles and are arranged in a certain direction. The ink supply port 107 is provided corresponding to the nozzle orifice 107a.

A plurality of buckling structures 101 are arranged on one surface of the substrate 105 with an insulating member 109 interposed therebetween. The buckling structure body 101 is made of, for example, a metal material such as nickel, and is provided so as to correspond to each nozzle orifice 111a.

From each buckling structure 101, the operation electrode 101a and the common electrode 10 are connected for connection with external electric means.
1b is pulled out. A power source (not shown) is connected to each operation electrode 101a via a switch.
The common electrode 101b is grounded.

Both ends of the buckling structure 101 are fixed to the substrate 105 with an insulating member 109 interposed. The insulating member 109 is made of an insulating material such as silicon oxide or alumina.

In the case 115, the concave portion 1 serving as an ink flow path is formed.
15a is provided in a desired shape.

With reference to FIGS. 4 and 5, the nozzle plate 111 described above is joined to the pressure generator 110 with a spacer 113 interposed, for example, by a non-conductive epoxy adhesive 119. At this time, the respective members are arranged so that the buckling structure body 101 is located directly below the respective nozzle orifices 111a with the respective openings 113a interposed. A housing 115 is joined to the pressure generator 110 with, for example, an epoxy adhesive (not shown).

The thickness T ₁ of the substrate 105 and the insulating member 109 is 20 μm or more. In addition, each ink supply port 10
The width W ₁ of the ink supply port 7 is, for example, 30 μm.
The length L _{1 of} 07 is, for example, about 30 μm.

The width W ₁ and the length L ₁ of the ink supply port 107 are not limited to the above values, and the ink supply port 107
The width W ₁ and the length L ₁ may be set so that the opening area (W ₁ × L ₁ ) of is less than 900 μm ² .

The dimensions of each part of the buckling structure 101 are as follows.
For example, the length L _{B of the} buckling portion is 600 μm and the width W _B is 60.
The thickness T _B is 6 μm.

Next, the ink jet head 1 of this embodiment
The operation of 50 will be described. Referring to FIG. 5, a voltage is applied to operating electrode 101a from an external power supply, and a current is passed through buckling structure body 101. Thereby, the buckling structure 10
1 is heated by resistance heat generation and tries to cause thermal expansion in the direction of arrow D ₁ . However, the buckling structure 101 is
Since both ends thereof are fixed, they cannot undergo thermal expansion deformation, and compressive force P in the buckling structure 101 in the direction of arrow F _1.
1 occurs. When the compressive force P ₁ exceeds the buckling load P _C , the buckling structure body 101 undergoes buckling deformation as shown in FIG.

Referring to FIG. 6, due to this buckling deformation, the central portion of buckling structure body 101 is displaced toward nozzle orifice 111a, and ink 80 filled in pressure chamber 113a.
The pressure is propagated to a, and the ink droplet 80a is formed from the nozzle orifice 111a and ejected to the outside.

Next, the ink jet head 1 of this embodiment
A method of manufacturing the pressure generator 110 used in the 50 will be described.

7 to 14 are schematic cross-sectional views showing, in the order of steps, a method of manufacturing a pressure generator used in the ink jet head according to the first embodiment of the present invention. First, referring to FIG. 7, a silicon substrate 1 having a thickness of 20 μm or more.
05 is prepared. Silicon substrate 1 with plane orientation (110)
Thermal oxide films 109a and 109b are formed on both front and back surfaces of No. 05 with a thickness of 1 μm, for example.

For convenience of explanation, the upper side of the substrate 105 in the figure is the front side and the lower side of the figure is the back side.

Next, referring to FIG. 8, a photoresist (not shown) is applied to the back surface of the substrate 105, and is patterned into a desired shape by exposure / development processing. Using this resist pattern as a mask, the thermal oxide film 10 is formed with CHF _3.
9b is etched. As a result, the thermal oxide film 1
An opening 109c is formed in 09b. After that, the resist pattern is removed.

Referring to FIG. 9, an aluminum film 131 having a thickness of, for example, 0.1 μm is formed on the surface of substrate 105 by, for example, a sputtering method. This aluminum film 131
Photoresist (not shown) is applied on top of the
It is patterned into a desired shape by the development processing. Aluminum film 131 using this resist pattern as a mask
The aluminum film 131 is patterned into a desired shape by etching.

Referring to FIG. 10, tantalum film 1 having a thickness of, for example, 0.01 μm is formed on the entire surface of silicon substrate 105.
01 and a nickel film 133 having a thickness of 0.1 μm are sequentially formed by, for example, a sputtering method. Nickel film 133
Is patterned into a desired shape by photolithography and etching.

Referring to FIG. 11, nickel film 133f having a thickness of 6 μm is formed by electrolytic plating using patterned nickel film 133 as an electrode. In this electroplating, nickel sulfamate, for example, is used as an electrolytic bath for nickel plating. After that, the nickel film 133 used as the electrode is removed by dry etching such as ion milling.

Referring to FIG. 12, by this removal, buckling structure body 101 having a two-layer structure of tantalum film 101e and nickel film 101f is formed. In this state, the silicon substrate 105 is dipped in a potassium hydroxide solution.

Referring to FIG. 13, the silicon substrate 1 exposed from the opening 109c of the thermal oxide film 109b is thereby formed.
The area 05 is etched. In this etching,
A plane-oriented (110) silicon substrate is anisotropically etched with a potassium hydroxide solution. That is, the plane orientation (11
When the silicon substrate 105 of 0) is etched, the (111) plane 107a having a slow etching rate remains, and the etching progresses in the direction perpendicular to the surface of the silicon substrate 105. As a result, the silicon substrate 105 is etched while the opening diameter of the opening 109c is substantially maintained, and the ink supply port 107 is formed. As a result, 900 μm
An ink supply port 107 having an opening area of ² or less is obtained. After that, the silicon substrate 105 is dipped in a hydrofluoric acid solution,
The exposed portions of the thermal oxide films 109a and 109b and the aluminum film 131 are removed by etching.

Referring to FIG. 14, the back surface and a part of the front surface of silicon substrate 105 are exposed by this etching. Further, a gap is formed between buckling structure body 101 and thermal oxide film 109. As a result, the pressure generator 110 is completed.

Thereafter, as shown in FIG. 3, the pressure generator 110 is joined to the nozzle plate 111, the spacer 113 and the casing 115 to complete the ink jet head 150.

The buckling structure body 101 shown in FIGS. 3, 4 and 5 is shown as a single-layer structure for convenience of explanation, but as shown in FIG. 14, it has a tantalum film 101e and a nickel film 101f. It may have a layered structure.

Next, the displacement amount and the temperature rise of the central portion of the buckling structure body in the ink jet head of this embodiment were simulated. The simulation result will be described.

Referring to FIGS. 4 and 5, buckling structure 10
The material of No. 1 is a nickel single layer, and the buckling length L _B is 60.
0 μm, width W _B is 60 μm, thickness T _B is 6 μm, and W ₁ and length L ₁ of the ink supply port 107 are each 30 μm.
m and the depth T ₁ was 20 μm. Further, the buckling structure body 101
Energy consumption per unit volume of 8 × 10 ⁸ J /
m ³ , power consumption 4 × 10 ¹³ W / m ³ , pulse width 20
The buckling structure was driven under the condition of μs (20 × 10 ⁻⁶ seconds).

FIG. 15A shows a drive waveform when the buckling structure is driven under the above conditions. Further, FIG. 15 (b)
[Fig. 6] is a graph in which the amount of displacement of the central portion of the buckling structure and the change in temperature rise when the buckling structure is driven under the above conditions are calculated by simulation.

When the response speed is calculated from the rising temperature curve of FIG. 15 (b), the rising response is 20 μs (20 × 1).
0 ^-6 seconds), and the falling response is 140 μs (140 × 1)
0 ^-6 sec), and it is possible to drive the buckling structure at 6 kHz. The reason why the buckling structure can be driven is that the rising response is relatively fast. Further, the rise response is relatively fast because the interval U ₁ between the buckling structure body 101 and the silicon substrate 105 shown in FIG. 5 is small.

Next, the ink jet head 1 of this embodiment.
The ejection speed of 50 ink drops was investigated.

The ejection speed of ink droplets can be calculated by a simulation based on fluid analysis. 16 and 1
7 is a plan view and a cross-sectional view in which the inkjet head 150 of the present embodiment shown in FIGS. 3, 4 and 5 is modeled for fluid analysis. Note that FIG. 17 shows the arrow X in FIG.
It is a schematic cross-sectional view taken along a ₂ -X ₂ line.

With reference to FIGS. 16 and 17, in the simulation by this fluid analysis, the moving speed V ₀ of the buckling structure body is given to the fluid 260 on the surface of the buckling structure body 201, and A so-called wall drive model is used to analyze motion.

In this model, the nozzle orifice 21
The nozzle plate 211 having 1a is connected to the surface of the substrate 205 via a spacer 213. Substrate 2
A case 215 having an ink flow path 215a on the back surface of 05.
Is connected. Further, the buckling structure body 201 includes the substrate 20.
The ink supply port 207 is provided on both sides of the buckling structure body 201.

The shape of the ink supply port 207 of this model is
It is necessary to match the shape of the ink supply port 107 of this embodiment.
However, considering the symmetry of the model, the ink supply port 20
7 was divided into two. Each of these ink supply ports 207
This width is W₁/ 2, length L ₁, Depth T₁And One
That is, the width of the ink supply port 207 in this model is 15
μm, the length is 30 μm, and the depth is 20 μm.

In this model, first, the buckling structure body 20 is
1 is displaced at a velocity of V ₀ . As a result, the pressure generated on the surface of the buckling structure body 201 propagates in the fluid 80 toward the nozzle plate 211 side. Further, a part of the pressure also propagates to the ink flow through the ink supply port 207. By the propagation of this pressure, the ink droplet 80a is ejected at a velocity V from the nozzle orifice 211a due to the pressure propagated to the nozzle plate 211 side.

The ejection speed V of the ink drop 80a in this model can be approximated to the ejection speed V of the ink drop of the ink jet head 150 in the first embodiment of the present invention. When the ejection speed of the ink droplets of this model is calculated using the above fluid analysis simulation, the ejection speed V is 2 m.
/ S. Therefore, the ejection speed of the ink droplet 80a of the inkjet head 150 shown in FIGS. 3, 4, and 5 can be approximated to 2 m / s.

Similarly, in the ink jet head 150 shown in FIGS. 3, 4, and 5, the width W ₁ and the length L ₁ of the ink supply port 107 are each 20 μm and the depth is the same while the size of the buckling structure is unchanged. When the thickness T ₁ is 20 μm and the buckling structure body 101 is driven under the same driving condition, the ink droplet ejection speed V becomes 3 m / s.

With the size of the buckling structure 101 unchanged, the width W ₁ and the length L ₁ of the ink supply port 107 are each 20 μm and the depth T ₁ is 50 μm, and the buckling structure 101 is under the same driving condition. Drive the ink droplet ejection speed V
Is 6 m / s.

From the above results, it can be seen that when the ink supply port is thin and long, the ejection speed of ink drops is improved. This is because when the ink supply port is thin and long, the fluid resistance of the ink that flows back toward the ink reservoir increases, it becomes difficult for the ink to flow back, and the pressure of the ink inside the cavity increases. it is conceivable that.

If the opening area of the opening of the ink supply port is larger than 900 μm ² or the depth T ₁ of the ink supply port 107 is smaller than 20 μm,
It was also confirmed by simulation that the ejection speed of ink droplets was lower than 2 m / s.

That is, in order to obtain the ink droplet ejection speed of 2 m / s or more, the opening area of the opening of the ink supply port 107 is 900 μm ² or less, and the ink supply port 107 is
The depth T ₁ of the metal must be 20 μm or more.

Next, a simulation for improving the heat dissipation of the heated buckling structure 101 will be described.

First, the apparatus shown in FIG. 18 was prepared for the simulation of heat dissipation.

FIG. 18 is a sectional view schematically showing the structure of an apparatus used for heat dissipation simulation. As a boundary condition, when the buckling structure 201 is first heated to 225 ° C., the buckling structure 201 moves to the nozzle plate side by 9
Deform by μm. Therefore, the simulation was performed with a structure in which the buckling structure body 201 was deformed by an average of 4.5 μm. Next, the buckling structure body 201 and the substrate 205 were placed in a container 214 which was 20 μm larger than the outer dimensions thereof, and the inside thereof was filled with ink, and the gap between the surface of the buckling structure body 201 and the liquid surface of the ink was set to 20 μm. The simulation was performed on the assumption that the inner surface of the container 214 and the bottom surface of the substrate 205 are kept at 25 ° C. Arrows indicate the main heat flow.

The changes in the rising response speed (Tr) and the falling response speed (Td) of the buckling structure 201 in the ink jet head 150 shown in FIGS. 4 and 5 are simulated using the apparatus shown in FIG. It was
The results are shown in FIGS. 19, 20 and 21.

During this simulation, the buckling structure 2
Thickness T _B (μm) of 01, buckling structure body 201 and substrate 20
5, the distance U ₁ (μm), and the length L of the ink supply port 107
_{1 (μm),} it was suitably changing the thickness T ₁ (μm) of the substrate 205.

In FIGS. 4 and 5, the buckling structure body 201 has a total length of 900 μm and a buckling portion length L _B of 300.
μm, and the thickness h of the substrate 205 is 500 μm. In addition,
The pulse height is 4.676W.

FIG. 19 shows the thickness T _B of the buckling structure and the rising response speed Tr (marked with Δ) and the falling response speed when the interval U ₁ = 1 μm and the length L ₁ of the ink supply port 107 is 100 μm. It is a graph which shows the relationship with Td (O mark).
The units of the rising and falling response speeds here are
It is represented by sec (second: time), and the shorter the time is, the faster the rising and falling speeds are. Hereinafter, FIGS.
The same applies to 1 and 22.

Referring to FIG. 19, the thickness T _{B of the} buckling structure body
The thinner is, the faster the response speed is for both Tr and Td. However, when the thickness Tb of the buckling structure is smaller than 6 μm, sufficient energy cannot be obtained to eject the ink droplet 80a from the nozzle orifice, and the ink droplet 80a cannot be ejected from the nozzle orifice. . Therefore, the lower limit of the optimum thickness of the buckling structure is 6 μm.

FIG. 20 shows the thickness T of the buckling structure._B= 6μ
m, ink supply port length L₁= 100 μm
Interval U between buckling structure 201 and substrate 205₁And stand up
Response speed Tr (△ mark) and falling response speed Td (○ mark)
It is a graph which shows the relationship with. Referring to FIG. 20, buckling
Distance U between structure 201 and substrate 205₁Is the rising response speed
It does not affect the degree Tr so much. But the falling response
The speed Td is the interval U ₁Becomes smaller and becomes faster.
Therefore, the head is driven at 2.5 kHz, for example.
In case of U₁Must be set to 5 μm or less
It Also, this interval U₁If is set to 1 μm or less,
It can be driven at 3.8 kHz.

FIG. 21 shows the thickness T _B of the buckling structure 101 =
6 μm, and the gap U between the buckling structure 101 and the substrate 105
Ink supply port 107 having a rising response speed Tr (Δ mark) and a falling response speed Td (◯ mark) when ₁ is changed appropriately
3 is a graph showing the dependence of the length L ₁ of the. With reference to FIG. 21, the length L ₁ of the ink supply port 107 has little influence on the rising response speed Tr. However, the falling response speed Td becomes faster as the length L ₁ of the ink supply port 107 becomes smaller. This tendency is the same regardless of the distance U ₁ between any buckling structure and the substrate.

Therefore, the head is, for example, 2.5 kH.
When driving at z, the gap U ₁ between the buckling structure and the substrate
Is set to 10 μm or less, the length L ₁ of the ink supply port 107 needs to be set to 40 μm or less. When the head is driven at 2.5 kHz, if the distance U ₁ between the buckling structure and the substrate is set to 5 μm or less, the length L ₁ of the ink supply port is 100 μm or less, that is, the buckling of the buckling structure. It is necessary to set the length to one third or less of the length of 300 μm.

Although not shown, the length L ₁ of the ink supply port is 40 μm or less, and the gap U between the buckling structure and the substrate is U.
_{If 1} is set to 5 μm or less, the head can be driven at 3.8 kHz.

In FIG. 22, the length L _B of the buckling portion of the buckling structure 101 is 300 μm, and the thickness T _B of the buckling structure 101 is 6 μm.
μm, the distance U ₁ between the buckling structure 101 and the substrate 105 is 2
Substrate 1 with μm and pulse height of 4.676W
5 is a graph showing the relationship between the thickness T _{1 of} 05 and the rising response speed Tr (marked with Δ) and the falling response speed Td (marked with ◯). Referring to FIG. 22, when the substrate thickness T ₁ is 20 μm or more,
The rising response speed Tr and the falling response speed Td are not so affected.

Further, instead of the silicon single crystal, for example,
When glass is used, the thermal conductivity is changed to silicon single crystal.
Compared with glass, the falling response speed Td is slower because the glass is inferior.
It Therefore, the material used for the substrate is silicon single bond.
70 W ・ m like a crystal^-1・ K ^-1Has the above thermal conductivity
Must be a material.

As a result, in order to increase the rising response speed Tr and the falling response speed Td and drive the head at 2.5 kHz, the interval U ₁ between the buckling structure body 101 and the substrate 105 should be 5 μm or less, Length L ₁ of ink supply port 107
Should be narrowed. The material of the substrate 105 may be any material having good thermal conductivity such as silicon single crystal, and may be a material having a thermal conductivity of 70 W · m ⁻¹ · K ⁻¹ or more.

In the ink jet head of this embodiment, the ink supply port 107 has a long path and a small opening area, so that the ink droplet ejection speed is improved. In particular, the path length of the ink supply port 107 is 20 μm or more, and the opening area of the ink supply port 107 is 9 at the opening end.
Since it is less than 00 μm ² , the ink ejection speed is 2 m / s
The above can be realized. Therefore, the design of the gap between the head and the printing paper is facilitated and the printing quality is improved.

The buckling structure body 101 is displaced in the thickness direction due to buckling. In this deformation due to buckling, even if the displacement amount in the plane direction is small, the small displacement amount can be converted into a large displacement amount in the thickness direction. Therefore, a large displacement amount can be obtained without increasing the size of the buckling structure body 101, and a large ejection force can be obtained. Further, in order to buckle the buckling structure body 101, it is sufficient to fix the buckling structure body 101 at both ends in the plane direction, and the structure thereof is very simple. From this point as well, it is easy to reduce the size. Therefore, it is possible to obtain the inkjet head 150 that can obtain a large ejection force while maintaining the size small.

When buckling is performed by heating, for example, it is necessary to heat the buckling structure body 101. However, in this case, it is not necessary to heat the buckling structure body 101 to a temperature at which the ink 80 itself is vaporized. That is, it is sufficient to heat the material to a temperature according to the coefficient of thermal expansion of the material. Therefore, it is not necessary to heat the buckling structure body 101 to a high temperature unlike the heater of a bubble jet type inkjet head. Therefore, thermal fatigue due to repetition of such high temperature heating and cooling is unlikely to occur, the buckling structure body 101 is less deteriorated, and its life is relatively long. Moreover, since the required amount of heat may be small, the power consumption can be small.

The distance U ₁ between the buckling structure 101 and the substrate 105, the opening area at the opening end of the ink supply port 107, and the material of the substrate 105 are limited to predetermined values and materials. For this reason, the heated buckling structure 101 is excellent in heat dissipation, and the responsiveness of displacement of the buckling structure 101 to heating / cooling is improved. Therefore, the buckling structure 10
The frequency response of 1 can be 2.5 kHz or more,
The printing speed of the printer is increased, and high-speed printing can be supported.

Further, since the opening diameter of the ink supply port 107 is 1/3 or less of the length L _B of the buckling portion of the buckling structure body, the area where the buckling structure body 101 and the substrate 105 face each other can be set large. . Thereby, the heat of the heated buckling structure body 101 is more easily released through the substrate 105, and the heat dissipation is further improved.

Further, the ink jet head 15 of the present embodiment.
In 0, both ends of the buckling structure 101 are supported so as to be sandwiched between the substrate 105 and the nozzle plate 111, but as shown in FIGS. 1 and 2, the buckling structure 1 is supported only on the substrate 5. It may be configured as described above. By supporting the buckling structure 1 only on the substrate 5 as shown in FIGS. 1 and 2, the buckling structure 1 is constantly displaced toward the nozzle plate 11 side. Hereinafter, this will be described in detail.

With reference to FIG. 1, both ends of buckling structure 1 are fixed to substrate 5 with insulating member 9 interposed on the back surface of buckling structure 1 facing nozzle orifice 11a. ing. The compressive force P ₀ during the operation of the inkjet head 50 is mainly generated at the joint surface between the insulating member 9 and the buckling structure 1. An axis at which the first moment of area of the buckling structure 1 is zero, a so-called centroid, passes through the center of the cross section of the buckling structure 1 in the longitudinal direction in the figure. Therefore, a deviation occurs between the centroid and the line of action of the compressive force P ₀ . Here, the compressive force P ₀ is applied to the centroid.
The line of action of is on the side opposite to the nozzle plate 11. As a result, a moment is generated in the direction of the arrow M ₀ along with the deviation between the compression force P ₀ and the centroid. This moment acts so that the central portion of the buckling structure 1 is displaced toward the nozzle orifice 11a side. For this reason, the central portion of the buckling structure 1 is always deformed toward the nozzle plate 11 side with the deformation due to buckling.

As a result, an appropriate ink droplet ejection can be realized, and accurate printing can be performed.

In this embodiment, for simplification of description, a multi-nozzle head having four nozzle orifices 111a is shown. However, in the ink jet head of the present invention, the nozzle orifice 1
The number of 11a is not limited to this and can be arbitrarily designed. Also, this nozzle orifice 11
The buckling structure body 101 and the ink supply port 107 may be provided corresponding to the number of 1a.

[Second Embodiment] Next, an ink jet head according to a second embodiment of the present invention will be described.

In the ink jet head 150 shown in FIGS. 4 and 5, the buckling structure body 101 is made of a nickel single layer, and its length L _B is 600 μm and width W _B is 60 μm.
m, the thickness T _B is 6 μm, and the width W of the ink supply port 107 is
₁ and length L ₁ are each 20 μm and depth T ₁ is 50 μm
And Moreover, the energy consumption per unit volume of the buckling structure body 101 is 8 × 10 ⁸ J / m ³ , and the power consumption is 8 × 10 ¹³
Buckling structure 101 with W / m ³ and pulse width of 10 μs
Driven.

FIG. 23A shows a drive waveform when the buckling structure is driven under the above conditions. Also, FIG.
(B) is a graph showing changes over time in the amount of displacement and the temperature rise of the central portion of the buckling structure body when the buckling structure body is driven under the above conditions.

Referring to FIG. 23B, compared with the simulation shown in FIG. 15, the driving pulse width is made shorter and the power consumption is made larger, so that the moving speed of buckling structure body 101 becomes faster. Similarly to the above, when the response speed is calculated from this rising temperature curve, the rising response is 10 μs (10
× 10 ^-6 seconds), falling response 140 μs (140 × 10
^-6 seconds), which enables driving at 6 kHz. The reason for this is that the fall response is relatively fast, as described above, and it is due to the fact that the substrate having high thermal conductivity is arranged in the vicinity of the buckling structure.

Further, similarly to the first embodiment, the moving speed V ₀ of the buckling structure is calculated as 15 m /
s. Therefore, the ejection speed of the ink droplets of the ink jet head having the above dimensions and the like can be approximated to 15 m / s, and the ejection speed is significantly improved.

This is the energy consumption (8 × 10 ⁸ J / m
^{Even if 3} ) is the same as in the first embodiment, since the driving pulse width is small and the power is large, the deformation speed of the buckling structure is high, the ink pressure is high, and the ink drop ejection speed is high. It is considered to be for improvement.

With the size of the above-described buckling structure, the width W ₁ and the length L ₁ of the ink supply port 107 were each 30 μm and the depth T ₁ was 20 μm. Energy consumption per unit volume of the buckling structure 101 is 8 × 10 ⁸ J / m ³ , power consumption is 4 × 10 ¹³ W / m ³ , and pulse width is 20 μs (20 × 10
^{When the} buckling structure body 101 was driven under the condition of ⁻⁶ seconds), the ejection speed of the ink droplet was 2 m / s. This is the ejection speed of ink drops that can be used as an inkjet head.

The width W ₁ and the length L ₁ of the ink supply port are narrowed to 20 μm, and the ink supply port 107
The depth T ₁ of the buckling structure to 50 μm, the energy consumption per unit volume of the buckling structure is not changed, the power consumption is increased to 8 × 10 ¹³ W / m ³ , and the pulse width is shortened to 10 μs. When driven in this manner, the ejection speed of the ink droplets becomes 15 ms /, and the performance of the inkjet head is further improved.

As described above, if the power consumption per unit volume of the buckling structure is not changed and the power consumption is doubled, that is, the pulse width is halved, the ink droplet ejection speed is 2.5. Double. However, if the energy consumption is increased more than necessary, the temperature of the buckling structure increases and deteriorates, resulting in a shorter life. Therefore, the energy consumption is 4 × 10 ⁹ J / m ³ or less per unit volume, preferably 8
It is preferable to drive at × 10 ⁸ J / m ³ or less.

The ink jet head of this embodiment has substantially the same effect as the ink jet head of the first embodiment.

In this embodiment, the material of the buckling structure is not limited to nickel, but any material having a large Young's modulus, a large coefficient of linear expansion and easy film formation may be used. The size of the buckling structure is the length L _B 600 μ mentioned above.
m, a width W _B 60 [mu] m, is not limited to the thickness T _B 6 [mu] m, the degree of integration impaired not required energy is put out size, for example, the length L _B is 300μm or more 900μm or less, the width W _B is 30μm or more 90μm Below, the thickness T _B is 3
It suffices if it is in the range of μm to 9 μm.

Further, in the first and second embodiments, the thermal oxidation film of silicon is used for the insulating member 109, but alumina may be used instead. When alumina is used, since the thermal conductivity is higher than that of the thermal oxide film of silicon, the cooling rate of buckling structure body 101 is increased and the frequency characteristic is improved. The film thickness of the insulating member 109 is preferably thick in order to secure the insulating property, but is preferably thin in order to conduct heat. Therefore, the film thickness is preferably 0.5 μm or more and 1 μm or less.

Further, the distance between the buckling structure 101 and the substrate 105, more precisely, the distance between the buckling structure 101 and the insulating member 109 is
The smaller the size, the faster the cooling rate of buckling structure body 101 and the better the frequency characteristics. On the contrary, if it is too small, the process becomes difficult. Therefore, the distance U ₁ is preferably ₁ μm or less, more preferably about 0.1 μm.

Further, the buckling structure 101 uses tantalum having a small linear expansion coefficient of 0.01 μm on the substrate side so that the buckling structure 101 bends toward the nozzle plate side, and the buckling structure 101 has a large linear expansion coefficient on the nozzle plate side. A two-layer structure of 6 μm nickel may be used. Similarly, the buckling structure 10
The temperature of the substrate is set lower than that of the nozzle plate side due to the heat radiation effect from the substrate so that 1 is bent toward the nozzle plate side.

[0138]

In the ink jet head according to the first and second aspects of the present invention, the ink supply speed is increased because the path of the ink supply port is long and the opening area is small. Therefore, the design of the gap between the head and the printing paper is facilitated and the printing quality is improved.

The buckling structure is buckled by being given a compressive force in its plane direction. In this buckling deformation, a small amount of displacement in the plane direction is converted into a large amount of displacement in the thickness direction of the buckling structure body. Therefore, a large displacement amount can be obtained without increasing the size of the buckling structure.

When the buckling structure body is to be buckled by heating, for example, it is necessary to heat the buckling structure body to a predetermined temperature. However, this heating temperature is sufficient if it is heated to a temperature according to the thermal expansion coefficient of the material forming the buckling structure,
It is not necessary to heat the ink to a temperature high enough to vaporize it. Therefore, deterioration of the buckling structure due to thermal fatigue is suppressed, and the life is relatively long.

Since the heating temperature is low, the amount of heat applied to the buckling structure can be small. Therefore, less power is consumed to drive the head.

In particular, in the ink jet head according to the second aspect, the gap between the buckling structure and the substrate, the opening area at the opening end of the ink supply port, and the material of the substrate are set to predetermined values and materials. Therefore, the heated buckling structure is excellent in heat dissipation, and the responsiveness of displacement of the buckling structure to heating / cooling is improved.

In the ink jet head according to the fourth aspect, since the opening diameter of the ink supply port is 1/3 or less of the length of the buckling portion of the buckling structure, the area where the buckling structure and the substrate face each other. Is set to a large value. Therefore, the heat of the heated buckling structure is more easily released through the substrate, and the heat dissipation is further improved.

In the ink jet head according to the fifth aspect, since both ends of the buckling structure are supported by the substrate on the back surface of the surface facing the nozzle orifice of the buckling structure, due to the action of the moment, The buckling structure is constantly displaced toward the nozzle plate. Therefore, the driving direction of the buckling structure can be controlled with a simple structure.

In the ink jet head according to the sixth aspect, the power consumption per unit volume of the buckling structure body is 4 × 10.
^{Since the} buckling structure is driven under the condition of ¹³ W / m ³ or more,
A sufficient ink ejection speed can be obtained. Therefore, the design of the gap between the head and the printing paper is facilitated and the printing quality is improved.

According to the method for manufacturing an ink jet head described in claim 7, an ink jet head having the effect described in claim 1 can be obtained. Further, since it can be formed by using the photolithography technique, the dimensional accuracy of the pattern is high, the mass production effect is large, and the high integration and the cost reduction can be realized.

[Brief description of drawings]

FIG. 1 is a main sectional view schematically showing a standby state of an inkjet head of the present invention.

FIG. 2 is a main sectional view schematically showing an operating state of the inkjet head of the present invention.

FIG. 3 is an exploded perspective view schematically showing the configuration of the inkjet head according to the first embodiment of the present invention.

FIG. 4 is a schematic sectional view taken along the X ₁ -X ₁ direction of FIG.

5 is a schematic cross-sectional view taken along the line YY of FIG.

FIG. 6 is a main cross-sectional view schematically showing an operating state of the inkjet head according to the first embodiment of the present invention.

FIG. 7 is a schematic cross-sectional view showing a first step of the method for manufacturing the pressure generator used in the ink jet head according to the first embodiment of the present invention.

FIG. 8 is a schematic cross-sectional view showing a second step of the method for manufacturing the pressure generator used for the ink jet head in the first embodiment of the present invention.

FIG. 9 is a schematic cross-sectional view showing a third step of the method for manufacturing the pressure generator used in the ink jet head according to the first embodiment of the present invention.

FIG. 10 is a schematic cross-sectional view showing a fourth step of the method for manufacturing the pressure generator used in the ink jet head according to the first embodiment of the present invention.

FIG. 11 is a schematic cross-sectional view showing a fifth step of the method for manufacturing the pressure generator used in the ink jet head according to the first embodiment of the present invention.

FIG. 12 is a schematic cross-sectional view showing a sixth step of the method for manufacturing the pressure generator used in the inkjet head of the first embodiment of the invention.

FIG. 13 is a schematic cross-sectional view showing a seventh step of the method for manufacturing the pressure generator used for the ink jet head in the first embodiment of the present invention.

FIG. 14 is a schematic cross-sectional view showing an eighth step of the method for manufacturing the pressure generator used in the ink jet head according to the first embodiment of the present invention.

FIG. 15 is a diagram (a) showing a drive waveform for driving the buckling structure, and a graph (b) showing a displacement amount of the central portion of the buckling structure body and a change amount of the temperature rise with time.

FIG. 16 is a plan view schematically showing the configuration of a model used for a fluid analysis simulation.

FIG. 17 is a schematic sectional view taken along line X ₂ -X ₂ in FIG.

FIG. 18 is a cross-sectional view schematically showing a configuration of an apparatus used for a simulation for improving heat dissipation.

FIG. 19 is a graph showing changes in rising response speed and falling response speed with respect to the thickness of a buckling structure.

FIG. 20 is a graph showing changes in rising response speed and falling response speed with respect to a gap between a buckling structure and a substrate.

FIG. 21 is a graph showing changes in rising response speed and falling response speed with respect to the length of the ink supply port.

FIG. 22 is a graph showing changes in rising response speed and falling response speed with respect to the thickness of a substrate.

FIG. 23 is a diagram (a) showing a driving waveform for driving the buckling structure, and a graph (b) showing changes in the displacement amount and the temperature rise of the central portion of the buckling structure with time.

FIG. 24 is a main cross-sectional view schematically showing the configuration of a conventional inkjet head using a piezoelectric element.

FIG. 25 is an exploded perspective view schematically showing the configuration of a conventional bubble-jet type inkjet head.

FIG. 26 is a diagram for explaining a recording principle of a conventional inkjet head of a bubble jet type.

FIG. 27 is a main cross-sectional view schematically showing the configuration of the inkjet head shown in the prior art document.

[Explanation of symbols]

 1, 101 Buckling structure 5, 105 Substrate 7, 107 Ink supply port 11, 111 Nozzle plate 11, 111a Nozzle orifice 15, 115 Housing 17 Power supply

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tetsuya Inui, 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (72) Inventor Shingo Abe 22-22, Nagaike-cho, Abeno-ku, Osaka, Osaka Incorporated (72) Inventor Kenji Ota 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka

Claims (7)

[Claims] 1. An inkjet head for applying pressure to an ink liquid filled inside to eject the ink liquid from the inside to the outside, the nozzle plate having a nozzle orifice, and a predetermined distance from the nozzle orifice. And a substrate provided with an ink supply port having opening ends facing each other, a central portion is located between the nozzle orifice and the opening end of the ink supply port, and both ends are supported by at least the substrate. A buckling structure, and a compressing means for applying a compressive stress to the inside of the buckling structure by heating, the buckling structure buckling due to the compressive stress applied by the compressing means, and the buckling structure The center portion of the ink is deformed toward the nozzle orifice, and the opening area of the ink supply port is 9 at the opening end.
The inkjet head has a thickness of 00 μm ² or less, a thickness of 20 μm or more, and the ink supply port extends in the thickness direction of the substrate and penetrates the substrate. 2. An ink jet head for ejecting an ink liquid from the inside by applying a pressure to the ink liquid filled in the inside, the nozzle plate having a nozzle orifice, and a predetermined distance from the nozzle orifice. And a substrate provided with an ink supply port having opening ends facing each other, a central portion is located between the nozzle orifice and the opening end of the ink supply port, and both ends are supported by at least the substrate. A buckling structure, and a compressing means for applying a compressive stress to the inside of the buckling structure by heating, the buckling structure buckling due to the compressive stress applied by the compressing means, and the buckling structure The center portion of the ink is deformed toward the nozzle orifice, and the opening area of the ink supply port is 9 at the opening end.
00 μm ² or less, the thickness of the substrate is 20 μm or more, the ink supply port extends in the thickness direction of the substrate and penetrates through the substrate, and the gap between the buckling structure body and the substrate is 5 μm. The following is further provided, and the material of the substrate further includes a material having a thermal conductivity of 70 W · m ⁻¹ · K ⁻¹ or more. 3. The ink jet head according to claim 1, wherein the ink supply port penetrates the substrate while maintaining an opening area that is substantially the same as an opening area at the opening end. 4. The ink jet head according to claim 1, wherein the opening diameter of the ink supply port at the opening end is 1/3 or less of the length of the buckling portion of the buckling structure. . 5. The buckling structure has a front surface facing the nozzle plate and a back surface located behind the front surface, and both ends of the buckling structure are supported by the substrate on the back surface. The inkjet head according to any one of claims 1 and 2, wherein: 6. A method of using an inkjet head for applying pressure to an ink liquid filled inside to discharge the ink liquid from the inside to the outside, the inkjet head comprising: a nozzle plate having a nozzle orifice; A substrate provided with an ink supply port having an opening end opposed to the nozzle orifice at a predetermined distance, a central part is located between the nozzle orifice and the opening of the ink supply port, and both ends are At least a buckling structure supported by the substrate, and a compressing means for applying a compressive stress to the inside of the buckling structure by heating, the buckling structure is buckled by the compressive stress applied by the compressing means. And the central portion of the buckling structure is deformed toward the nozzle orifice side, and the thickness of the substrate is 20 μm or more. The opening area of the supply port, in the open end 9
Is less than or equal to 00 μm ² , the ink supply port extends in the thickness direction of the substrate and penetrates through the substrate while maintaining the opening area at the opening end, and the buckling structure is the buckling structure. A method for using an inkjet head, which is driven under the condition that the power consumption per unit volume of the body is 4 × 10 ¹³ W / m ³ or more. 7. A method of manufacturing an inkjet head, wherein pressure is applied to an ink liquid filled inside to discharge the ink liquid from the inside to the outside, the step of preparing a substrate having a thickness of 20 μm or more, and both ends. Part is supported on the main surface of the substrate, a central part forms a buckling structure so as to be separated from the main surface of the substrate by a predetermined distance, and the buckling structure penetrates the substrate in the thickness direction. Forming an ink supply port having an opening end facing the central portion of the nozzle so that the opening area at the opening end is 900 μm ² or less; forming a nozzle plate having a nozzle orifice; Bonding the nozzle plate to the substrate so that the central portion of the body is located between the nozzle orifice and the opening end of the ink supply port.
Inkjet head manufacturing method.