JPH091795A - Ink jet head - Google Patents

Abstract

PURPOSE: To achieve an effective heat radiation and a satisfactory response speed by forming a pressure generating means of a driving body having a central part narrower than both the ends in width, and generating buckling deformation by thermal expansion, a heater layer at the lower part of the driving body, and a diaphragm layer on the upper part thereof. CONSTITUTION: On a silicon single substrate 1, there is provided successively a diaphragm 2, a first insulating layer 3, a heater layer 4, a second insulating layer 5, and a buckling body 6 as a driving body generating buckling deformation from thermal expansion, and further a nozzle plate 7 having a nozzle 12 formed thereon. The buckling body 6 is joined with the diaphragm 2 at the central connection part 10, and secured to the substrate 1 at the securing part 6a, and its root part 6b and central part 6c arc spaced apart from the substrate 1 through the gap 9, and the central part 6c is formed narrower than the securing part 6a and root part 6b in width W. Thus, when the diaphragm 2 or the like is deformed, since the distance between the heater layer 4 and the substrate 1 scarcely vary, the distance is made shorter, the element can be formed with a fast heat-radiation and good response speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head for recording by applying pressure to an ink liquid filled inside to eject ink from the inside to a recording method.

[0002]

2. Description of the Related Art Conventionally, so-called ink jet printers have been developed which perform recording by ejecting liquid ink from minute nozzles. FIG. 7 shows the structure of a head that has been conventionally used as a method for ejecting ink. A part of the pressure generating member is fixed on the substrate,
Part of it is floating. Further, a heat generating member is formed together with the pressure generating member. When the heat generating member is energized, the pressure generating member is heated and deforms in the direction perpendicular to the substrate. Therefore, the pressure of the ink chamber is increased, and the ink can be ejected from the nozzle opening provided in the nozzle plate.

[0003]

However, the conventional head has the following problems. After the pressure generating member is deformed, it is necessary to promptly return to the original state.
This is because the head needs to be driven at high speed in order to increase the printing speed of the printer. In order to return to the original state, the temperature of the heated pressure generating member needs to be rapidly reduced, and heat is radiated through the ink layer.

Here, the process of cooling the pressure generating member is mainly governed by heat conduction. First, the heat of the pressure generating member is transmitted to the surrounding ink and further to the surrounding substrate to be radiated. The heat conductivity of the substrate (solid) is generally higher than that of the liquid, so that the heat dissipation in the substrate is good. That is, when the pressure generating member is deformed and separated from the substrate in FIG. 7, the distance between the pressure generating member and the substrate increases, and the heat dissipation effect deteriorates. Heat is accumulated around the heater by continuously driving the head, and when this heat increases with time, the temperature of the entire head gradually rises,
In severe cases, there is a problem in that the quality of the ink may change and the ink may boil.

In view of these problems, it is an object of the present application to provide an ink jet head that effectively radiates heat and has a good response speed.

[0006]

In order to solve the above problems, in an ink jet head of the present invention, pressure generating means for generating a pressure for ejecting ink onto a substrate and a nozzle at a position facing the pressure generating means are provided. And a nozzle plate having a nozzle plate having a pressure generating means, wherein the pressure generating means has a central portion formed to be narrower in width than both end portions, and causes a buckling deformation due to thermal expansion, and both end portions of the driving body. It is characterized in that it is formed by a heater layer provided under the portion and a diaphragm formed under the driver and the heater layer.

Further, in an ink jet head provided with a pressure generating means for generating a pressure for ejecting ink on a substrate, and a nozzle plate having a nozzle at a position facing the pressure generating means, the pressure generating means Is a diaphragm, a drive member formed in a lower portion of the diaphragm, having a central portion having a narrower width than both end portions, and a buckling deformation caused by thermal expansion. And a formed heater layer.

Further, in an ink jet head provided with a pressure generating means for generating a pressure for ejecting ink onto the substrate, and a nozzle plate having a nozzle at a position facing the pressure generating means, the pressure generating means is provided. Is a diaphragm, a drive member that is formed in the lower portion of the diaphragm, has a central portion that is thinner than both end portions, and causes buckling deformation due to thermal expansion, and a lower portion of both end portions of the drive member. And a heater layer provided.

[0009]

In the ink jet head of the present application, the structure in which the width of the central portion of the driving body is narrowed makes it less likely that both ends thereof will buckle, and only the central portion will buckle. Since the heater layer is formed only on both ends of the driving body, the distance between the heater layer and the substrate can be kept constant even during operation, and the heat dissipation effect is improved.

Further, when the surface of the driving body is covered with the diaphragm, the width of the central portion is narrowed so that only the central portion is deformed so that the distance between the heater layer and the substrate can be kept constant. At the same time, the temperature rise on the surface of the diaphragm can be suppressed.

Further, when the shape of the driving body is thin only in the central portion, the heater layers are arranged at both ends of the driving body, and the diaphragm is formed so as to cover the entire surface of the driving body, the driving is performed. Deformation occurs only in the central part of the body and the distance between the heater layer and the substrate can be kept constant, and at the same time the deformation force increases due to the difference in thickness,
The width of the driver can be reduced.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIG. 1A shows a first embodiment according to the present invention. Diaphragm 2, first on silicon single crystal substrate 1
The insulating layer 3, the heater layer 4, the second insulating layer 5, and the buckling body 6 are sequentially formed, and the nozzle plate 7 having the nozzle 12 is formed thereon. Here, the buckling body refers to a driving body that undergoes buckling deformation due to thermal expansion.

A back surface through hole 8 is formed in the substrate 1, and a gap 9 is formed between the diaphragm 2, the first insulating layer 3 and the buckling member 6. Buckling body 6 and diaphragm 2
Are connected by a central connecting portion 10.

FIG. 1B is a plan view of the head. The fixed portion 6a is a portion of the buckling body 6 that is fixed to the substrate 1, and the root portion 6b and the central portion 6c are separated from the substrate 1 by the gap 9. Central part 6 of buckling body 6
The width c of the c is narrower than that of the fixed portion 6a and the root portion 6b. Further, the heater layer 4 is formed by fixing the buckling member 6 to the fixed portion 6 thereof.
It is formed only from a to the root portion 6b, and the central portion 6
It is not formed in c.

A portion surrounded by the nozzle plate 7 and the diaphragm 2 is an ink chamber 11, and ink is ejected from the nozzle 12 by increasing the pressure of the ink chamber 11.

The feature of this embodiment is that the shape of the buckling body 6 is narrowed only in the central portion, and the heater layer 4 is formed only in the wide root portion and the fixed portion of the buckling body 6. There is something I did.

Next, the operation of this embodiment will be described. FIG. 2 shows the operation of the device of this example. Heater layer 4
When a current is applied to the buckling body 6 to heat it, the buckling body 6 thermally expands and extends in the direction indicated by the arrow A. However, since the width of the central portion 6c of the buckling member 6 is narrower than that of the both end portions, the compressive stress in this portion is larger than that in the root portion 6b, and the buckling stress is increased before the root portion 6b buckles. Buckling occurs at the crossing point.
Therefore, as shown in FIG. 2, only the central portion of the buckling body 6 is deformed, and the root portion 6b is deformed very little. Further, since the diaphragm 2 connected to the diaphragm 2 is connected to the central portion 6c, it is greatly deformed, so that the ink chamber is pressurized to eject the ink.

Next, a second embodiment according to the present invention will be described with reference to FIG.
(A). On the silicon single crystal substrate 13, the first insulating layer 14, the heater layer 15, the second insulating layer 16, the buckling body 17,
The diaphragm 18 is sequentially formed, and the nozzle 2 is formed on the diaphragm 18.
Nozzle plate 19 having 4 is formed.

A back surface through hole 20 is formed in the substrate 13. Further, gaps 21 and 22 are formed between the buckling body 17 and the diaphragm 18, and between the substrate 13 and the first insulating layer 14, respectively. Buckling body 17 and diaphragm 1
8 are connected by a central connecting portion 25.

FIG. 3B is a plan view of the head. The fixed portion 17a of the buckling body 17 is fixed to the substrate 13, but the root portion 17b and the central portion 17c are separated from the substrate 13 by the gap 22. Further, the central portion 17c of the buckling body 17 is formed to be narrower than the root portion 17a and the fixed portion 17b. The heater layer 15 is a buckling member 17
Is formed only from the fixed portion 17a to the root portion 17b, and is not formed in the central portion 17c.

A portion surrounded by the nozzle plate 19 and the diaphragm 18 is an ink chamber 23, and ink is ejected from the nozzle 24 by increasing the pressure of the ink chamber 23.

The characteristic feature of this embodiment is that the buckling member 17 is used.
Is formed in a narrow width only in the central portion 17c, and the heater layer 15 is formed only in the wide root portion 17b and the fixed portion 17a of the buckling body 17, and the diaphragm is formed so as to cover the entire buckling body 17. 18 is placed.

Next, the operation of this embodiment will be described. FIG. 4 shows the operation of the device of this example. Heater layer 1
When a current is passed through 5 to perform heating, the buckling body 17 expands due to thermal expansion and extends in the direction indicated by arrow B. However, since the central portion 17c of the buckling body 17 is formed narrower than both end portions, the compressive stress in this portion is the root portion 17b.
The buckling stress is exceeded before the root portion 17b buckles, and buckling occurs. Therefore, as shown in FIG. 4, only the central portion of the buckling body 17 is deformed, and the root portion 17b is deformed very little. Also the diaphragm 18
Is deformed largely because it is connected to the buckling body 17 at the center. Therefore, there is a function of pressurizing the ink chamber to eject the ink.

Next, a third embodiment according to the present invention is shown in FIG. A first insulating layer 27, a heater layer 28, a second insulating layer 29, a buckling body 30, and a diaphragm 31 are sequentially formed on a silicon single crystal substrate 26, and a nozzle plate 36 having a nozzle 37 is formed thereon. There is.

A back surface through hole 32 is formed in the substrate 26. Further, the substrate 26, the first insulating layer 27, and the buckling member 30.
Gap 33 and 34 are respectively formed between and the diaphragm 31. Buckling body 30 and diaphragm 3
The 1's are joined by a central connecting portion 35. FIG.
(B) is a plan view of the head.

The characteristic feature of this embodiment is that the buckling member 30 is used.
Is formed so that only the central portion has a small thickness, the heater layer 28 is formed only on the root portion and the fixed portion of the buckling body 30, and the diaphragm 31 is arranged so as to cover the entire surface of the buckling body 30. is there. According to this structure, the buckling body buckles due to heating, but since the thickness of the central portion is thin, this portion buckles first, resulting in deformation only in the central portion. The deformation of the part is very small. Further, since the force acting on the central portion becomes larger due to the difference in thickness, it becomes possible to cause the buckling deformation even if the width of the buckling body is further narrowed, and the elements are densely packed as shown in FIG. 5 (b). Can be formed.

Next, a method of manufacturing an ink jet head according to the present invention will be described with reference to FIG. First, as shown in FIG. 6A, thermal oxide films 39 are formed on both surfaces of the silicon single crystal substrate 38. Subsequently, as shown in FIG. 6B, patterning is performed on the back surface to remove the thermal oxide film only in the portion corresponding to the shape 40 of the back surface supply port. Then, as shown in FIG. 6C, the substrate is immersed in an etching solution containing KOH as a main component for anisotropic etching to form a back surface supply port 41. However, at this time, the back surface supply port does not penetrate the substrate 38, and etching is stopped midway so that there is no hole on the surface of the substrate 38.

Next, as shown in FIG. 6D, the sacrificial layer 42 is formed on the surface.
Is formed. As the material of the sacrificial layer, Al, Zn or photoresist can be used. This sacrificial layer is provided to form a step in the circumferential direction of the diaphragm formed next, but it is not always necessary and may be omitted. Next, as shown in FIG. 6E, a metal diaphragm layer 43 is formed on the surface. As the material of the diaphragm, nickel, copper, cobalt or an alloy thereof can be used and can be formed by electroplating. Subsequently, as shown in FIG. 6F, a sacrificial layer 44 is formed on the surface and patterned. As the material of the sacrificial layer, Al, Zn, photoresist or the like can be used. A portion where the sacrificial layer is not provided is provided in the central portion of the sacrificial layer. Next, a heater layer 45 sandwiched between insulating layers is provided as shown in FIG. 6 (g), and a buckling body layer 46 is provided thereon as shown in FIG. 6 (h). The buckling body can be formed by electroplating using nickel, copper, cobalt or an alloy thereof. When forming the buckling body layer, it is possible to form a buckling body layer in a desired pattern by providing a resist pattern in a portion where plating is not performed so that the plating layers are not laminated. At this time, as a planar shape, as shown in FIG. 1, the root portion is formed wider than the central portion. In addition, the heater layer formed in FIG. 6G is formed so as to be located only under the root portion and the fixed portion of the buckling body.

Subsequently, as shown in FIG. 6 (i), the entire substrate is immersed in an etching solution containing KOH as a main component, and a back surface supply port is provided by anisotropic etching. At this time, the back surface supply port is formed by anisotropic etching, and the thermal oxide film is KO.
Since it is hard to be etched by H, anisotropic etching is stopped by the thermal oxide film firstly provided on the silicon substrate.
Next, as shown in FIG. 6J, the thermal oxide film exposed at the back surface supply port is removed by etching. As an etching method, hydrofluoric acid, a buffer solution containing hydrofluoric acid, or dry etching using CF ₄ gas or the like can be performed. Then, the sacrifice layer is removed by etching as shown in FIG. The sacrificial layer between the buckling body and the diaphragm is etched when the etching solution enters from the side surface of the buckling body. Finally, as shown in FIG. 6 (l), the orifice plate 47 is adhered to produce an inkjet head.

[0031]

In the first embodiment, as shown in FIG. 2, even if the central portion 6b of the buckling member 6 and the diaphragm 2 are deformed, the buckling member root portion 6a having the heater layer 4 is hardly deformed. . Therefore, the distance between the heater layer 4 and the substrate 1 hardly changes, and the heat radiation from the heater layer 4 is less likely to be hindered. Since the distance from the substrate 1 can be set to 1 micron or less by forming the sacrificial layer,
It is possible to obtain an element having a high heat dissipation rate and a good response speed.

Further, in the first embodiment, the diaphragm 2
It is not always necessary to fill the back surface supply port 8 on the back side with the liquid. Since the heat radiation from the heater layer 4 is conducted to the substrate 1 through the gap 9, it is not necessary to perform the heat radiation through the central portion of the diaphragm, and there is an air layer having a low thermal conductivity on the back side of the diaphragm 2. This is because it does not matter. This is a great advantage for the operation of the device. This is because when the back surface is filled with a liquid (for example, ink), the ink on the back surface is moved at the same time as the movement of the diaphragm 2, which increases the weight of the movable portion of the element and increases the response frequency of the element. This is the cause of the decrease. However, when the back surface is an air layer as in this embodiment, its mass is so small that it can be ignored as compared with ink of the same volume, and the weight of the movable part can be reduced, so that the response frequency is improved and the response speed is improved. A good element can be obtained.

According to the second embodiment, since the distance between the heater 15 and the substrate 13 does not change, the effect of heat radiation is not hindered, as in the first embodiment. In addition, in Example 2,
In addition to this, since the diaphragm 18 covers the buckling member 17, the heat of the heater 15 is less likely to be transferred to the ink chamber 23, and the quality of the ink in the ink chamber 23 is less likely to change.

According to the third embodiment, the distance between the heater 28 and the substrate 26 does not change, the effect of heat radiation is not hindered, and the diaphragm 31 covers the buckling member 30, so that the heater 28 As in Examples 1 and 2, the heat is less likely to be transferred to the ink chamber and the quality of the ink in the ink chamber is less likely to change. Further, in Example 3, the buckling member 3
Since the thickness of the central portion of 0 is thinned and the force acting on the central portion is increased to easily cause buckling, the element width can be made narrower than in the first and second embodiments. Therefore, the interval between the elements can be reduced, and the elements can be closely arranged to form a head with high resolution.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of an inkjet head of the present invention.

FIG. 2 is a diagram showing a driven state of the inkjet head of FIG.

FIG. 3 is a diagram showing a second embodiment of the inkjet head of the present invention.

FIG. 4 is a diagram showing a driven state of the inkjet head of FIG.

FIG. 5 is a diagram showing a third embodiment of the inkjet head of the present invention.

FIG. 6 is a diagram illustrating a method of manufacturing an inkjet head according to the present invention.

FIG. 7 is a diagram showing a conventional inkjet head.

[Explanation of symbols]

 1 Substrate 2 Diaphragm 3 First Insulating Layer 4 Heater Layer 5 Second Insulating Layer 6 Buckling Element 7 Nozzle Plate 9 Gap 11 Ink Chamber 12 Nozzle

Front page continuation (72) Inventor Yoronari Ishii, 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Shingo Abe, 22-22 Nagaike-cho, Abeno-ku, Osaka, Osaka (72) Inventor Shoji Kimura, 22-22 Nagaikecho, Nagano-cho, Abeno-ku, Osaka, Osaka Prefecture (72) Inventor, Dai Horiko, 22-22, Nagaike-cho, Abeno-ku, Osaka, Osaka (72) Inventor Yutaka Onda 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Prefecture

Claims (3)

[Claims] 1. An ink jet head comprising: a pressure generating means for generating a pressure for ejecting ink onto a substrate; and a nozzle plate having a nozzle at a position facing the pressure generating means. Is a driver whose central portion is formed to have a width narrower than that of both ends, and which causes buckling deformation due to thermal expansion, a heater layer provided below both ends of the driver, the driver and the heater layer. And a diaphragm formed on the lower part of the ink jet head. 2. An ink jet head comprising: a pressure generating means for generating a pressure for ejecting ink onto a substrate; and a nozzle plate having a nozzle at a position opposed to the pressure generating means, wherein the pressure generating means. Is a diaphragm, a drive member formed in a lower portion of the diaphragm, having a central portion having a narrower width than both end portions, and a buckling deformation caused by thermal expansion. And a heater layer formed on the ink jet head. 3. An ink jet head comprising: a pressure generating means for generating a pressure for ejecting ink onto a substrate; and a nozzle plate having a nozzle at a position facing the pressure generating means, wherein the pressure generating means. Is a diaphragm, and a driving member that is formed in a lower portion of the diaphragm and has a structure in which a central portion is thinner than both end portions and causes buckling deformation due to thermal expansion.
An ink jet head formed by a heater layer provided below both ends of the driving body.