JPH08142323A - Ink jet head and manufacture thereof - Google Patents

Abstract

PURPOSE: To provide an ink jet head capable of having a good responsiveness against heating or cooling and of printing at high speed. CONSTITUTION: A nozzle plate 10 having a nozzle opening 11 and a substrate 7 form a part of a circumferential wall of an ink chamber 31. A pressure generation member 20 is provided in the ink chamber 31. A pressure generation member 20 comprises a buckling body 1, a heater layer 3 and a diaphragm 5. The buckling body 1 which is roughly in plate-shaped and of which circumferential section is attached to the substrate 7 can take a non-displacement condition substantially having no-thermal stress or a buckling condition wherein it is buckled by the thermal expansion. The heater layer 3 is provided along a face on a side of the substrate 7 of the buckling body 1. The diaphragm 5 is made of a roughly plate-shaped flexible material and is provided along a face on a side of the nozzle plate 10 of the buckling body 1 in such a manner that at least a circumferential section 5c is attached to a circumferential section 1c of the buckling body 1.

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 ejecting and flying ink liquid. The invention also relates to a manufacturing method thereof.

[0002]

2. Description of the Related Art Ink jet heads based on various droplet ejection principles have been commercialized. For example, one in which ink is ejected from a nozzle hole of an ink chamber by mechanical deformation of a piezoelectric element (piezoelectric element method), ink is boiled by heating with a heater to form bubbles, and pressure changes due to the bubble generation There is a device (bubble jet system) in which ink is ejected from a nozzle.

Under such circumstances, recently, as shown in FIG. 21, a pressure generating member 50 which is heated by electric current and deforms.
An inkjet head 510 using No. 1 has been proposed (Japanese Patent Publication No. 30543/1990). In this inkjet head 510, a pair of electrodes 513b and 513b are provided on both ends of a nozzle plate 511 having a nozzle opening 511a via insulating films 513a and 513a, and a plate-shaped pressure generating member 5 is provided on these electrodes 513b and 513b.
01 is bridged and connected, and a cover member 515 is provided so as to accommodate them. In operation, the ink 80 is supplied from the preliminary ink chamber 532, and the gap 530 between the nozzle plate 511 and the pressure generating member 501 and the back side 531 of the pressure generating member 501 are filled with the ink 80. Then, during the heating period, the pressure generating member 501 is energized to generate heat through the electrodes 513b and 513b. Due to this heat generation, the pressure generating member 501 receives thermal stress due to the thermal expansion coefficient, the central portion is displaced in the direction perpendicular to the plate surface, and pressure is generated in the ink chamber, whereby the ink 80 from the nozzle opening 511a. Are discharged in a granular form. When the cooling period is entered after the heating period is finished, the energization is stopped, and the pressure generating member 501 is cooled and returns to its original shape (position). By repeating such heating period and cooling period,
The displacement and return of the pressure generating member 501 are repeated.

[0004]

However, in the above-mentioned ink jet head 510, the pressure generating member 501 is used.
There is almost no improvement in the heat dissipation of the ink, and in particular, only the ink 80 having a relatively small thermal conductivity is present on the ink preliminary chamber 532 side of the pressure generating member 501. Therefore, the cooling rate of the pressure generating member 501 becomes slow during operation, and as a result, there is a problem that the response characteristics are poor and high-speed printing cannot be performed. In addition, the pressure generating member 501
Since the gap 530 on the nozzle plate side and the space 531 on the back side of the nozzle plate 51 directly communicate with each other, the ink existing in the gap 530 between the nozzle plate 511 and the pressure generating member 501 is generated by the pressure generating member 501 during operation by the nozzle plate 51.
When pressure is applied to one side, the space 5 on the back side of the pressure generating member
It is easy to get around 31. Therefore, there is a problem that the ejection force and the ejection speed of the ink are small.

Therefore, an object of the present invention is to provide an ink jet head having good response characteristics by heating and cooling and capable of high speed printing. Further, it is possible to provide an inkjet head that can prevent ink existing in the gap between the nozzle plate and the pressure generating member from wrapping around to the back side of the pressure generating member and increase the ejection force and ejection speed of the ink. is there. Also,
It is to provide a small-sized and long-life inkjet head. Another object of the present invention is to provide a method for manufacturing an inkjet head, which can easily manufacture the inkjet head as described above in a small size.

[0006]

An ink jet head according to a first aspect of the present invention is provided with an ink chamber including a nozzle plate having a nozzle opening and a substrate facing the nozzle plate in a part of a peripheral wall, and the ink chamber. A pressure generating member facing the nozzle plate, and by generating a pressure in the ink chamber by deformation of the pressure generating member,
An ink jet head for ejecting an ink liquid in the ink chamber to the outside through the nozzle opening, wherein the pressure generating member has a substantially plate shape, and portions of the peripheral edge portion that are at both ends in at least one direction are attached to the substrate. A buckling body that can take a non-displacement state where there is substantially no thermal stress and a buckling state where it buckles due to thermal expansion, and is provided along one surface of this buckling body to generate heat when energized. And a heater layer that operates.

According to another aspect of the present invention, in an ink jet head, an ink chamber including a nozzle plate having a nozzle opening and a substrate facing the nozzle plate in a part of a peripheral wall, and a nozzle plate provided in the ink chamber are provided. An ink jet head comprising: a pressure generating member facing each other, the pressure being generated in the ink chamber by the deformation of the pressure generating member, and the ink liquid in the ink chamber being ejected to the outside through the nozzle opening. The member has a substantially plate-like shape, and portions of the peripheral edge that are at both ends in at least one direction are attached to the substrate, and there is substantially no thermal stress in the non-displacement state and the buckling state in which the member expands due to thermal expansion. And a buckling body that can be made of a substantially plate-shaped flexible material. Periphery is characterized in that a diaphragm is provided in a state of being attached to the periphery of the buckling member.

According to another aspect of the present invention, in an ink jet head, an ink chamber including a nozzle plate having a nozzle opening and a substrate facing the nozzle plate in a part of a peripheral wall thereof is provided in the ink chamber. An ink jet head comprising: a pressure generating member facing each other, the pressure being generated in the ink chamber by the deformation of the pressure generating member, and the ink liquid in the ink chamber being ejected to the outside through the nozzle opening. The member has a substantially plate-like shape, and portions of the peripheral edge that are at both ends in at least one direction are attached to the substrate, and there is substantially no thermal stress in the non-displacement state and the buckling state in which the member expands due to thermal expansion. And a heater layer which is provided along one surface of the buckling body and which generates heat when energized, and a substantially plate-shaped flexible material. And a diaphragm provided along the surface on the nozzle plate side of both surfaces of the buckling body and with the peripheral edge portion attached to the peripheral edge portion of the buckling body. I am trying.

An ink jet head according to a fourth aspect is the ink jet head according to the first or third aspect, wherein the heater layer extends along both of the surfaces of the buckling member on the substrate side. It is characterized by being provided.

An ink jet head according to a fifth aspect is the ink jet head according to any one of the first, third and fourth aspects, wherein the pressure generating member is
It is characterized in that it has a first insulating layer provided between the substrate and the heater layer.

An ink jet head according to a sixth aspect is the ink jet head according to any one of the first, third, fourth and fifth aspects, wherein the pressure generating member is the buckling member and the heater layer. Second provided between and
It is characterized by having an insulating layer.

An ink jet head according to a seventh aspect is the ink jet head according to the second or third aspect, wherein the diaphragm is formed in a substantially disc shape.

An ink jet head according to an eighth aspect is the ink jet head according to any one of the second, third, and seventh aspects, in addition to the peripheral edge portion of the diaphragm, other than the peripheral edge portion of the diaphragm. At least a part is connected to the buckling body.

An ink jet head according to a ninth aspect is the ink jet head according to any one of the second, third, seventh, and eighth aspects, wherein the central portion of the diaphragm is the central portion of the buckling body. It is characterized by being connected to.

An ink jet head according to a tenth aspect of the present invention is the ink jet head according to any one of the second, third, seventh, eighth, and ninth aspects, wherein the peripheral portion and the buckling of the diaphragm are the same. A feature is that a gap is provided between the buckling body and an intermediate portion between the portion connected to the body.

An ink jet head according to an eleventh aspect of the present invention is the ink jet head according to any one of the first to tenth aspects, wherein the pressure generating member is located inside the peripheral portion of the buckling member. A feature is that a gap is provided between the existing portion and the substrate.

According to a twelfth aspect of the present invention, in the ink jet head according to the eleventh aspect, the distance between the substrate and the portion of the pressure generating member is in the range of 0.05 μm to 2.0 μm. It is characterized by being set inside.

An ink jet head according to a thirteenth aspect is the ink jet head according to any one of the first to twelfth aspects, wherein the pressure generating member is located inside the peripheral portion of the buckling member. A slit that penetrates from the surface facing the substrate to the surface of the buckling body on the diaphragm side is provided in the existing portion.

An ink jet head according to a fourteenth aspect is the ink jet head according to the thirteenth aspect, wherein a plurality of the slits are provided and a belt-shaped portion of the buckling member sandwiched by the slits buckles. It is characterized by that.

An ink jet head according to a fifteenth aspect is the ink jet head according to any one of the first to fourteenth aspects, wherein the substrate is penetrated through the substrate to form the pressure generating member. It is characterized in that a refrigerant circulation hole is provided so as to face a portion of the buckling body located inside the peripheral portion.

According to a sixteenth aspect of the present invention, in the ink jet head according to the fifteenth aspect, the coolant circulation hole is located from the side opposite to the pressure generating member of the substrate to the pressure generating member side. The feature is that the dimension becomes gradually smaller toward.

The ink jet head according to a seventeenth aspect is the ink jet head according to the fifteenth or sixteenth aspect, wherein a refrigerant reservoir communicating with the refrigerant circulation hole is provided on a side of the substrate opposite to the pressure generating member. It is characterized by being formed.

According to the eighteenth aspect of the present invention, in the ink jet head manufacturing method, an ink chamber including a nozzle plate having a nozzle opening and a substrate facing the nozzle plate in a part of a peripheral wall, and the ink chamber are provided in the ink chamber. A pressure generating member facing the nozzle plate, wherein the pressure generating member is a plate-shaped buckling body, a heater layer provided on the substrate side of the buckling body, and the nozzle plate of the buckling body. A method for manufacturing an inkjet head having a diaphragm provided on a side thereof, the method comprising: forming a first sacrificial layer having a pattern occupying a predetermined closed region on a surface of a substrate; First above
Forming a first insulating layer made of a material that can be selectively etched with the first sacrificial layer so as to cover the sacrificial layer;
A step of forming a heater layer having a pattern passing through a region occupied by the first sacrificial layer on the first insulating layer; and a material which can be selectively etched with the first sacrificial layer so as to cover the layers. Forming a second insulating layer, and forming a slit along both sides of the heater layer pattern from the surface of the second insulating layer to the surface of the first sacrificial layer; A step of applying a resist and performing photolithography to fill the inside of the slit and form a resist wall protruding by a predetermined height from the surface side of the second insulating layer while maintaining the width of the slit; A step of forming a first metal layer for forming a buckling member on the second insulating layer by a plating method to a predetermined thickness that does not exceed the height of the resist wall; and the first sacrificial layer. Approximately corresponding closed area, Forming a second sacrificial layer made of a material that can be selectively etched with the first metal layer so as to cover a predetermined portion of the surface of the first metal layer and the slit; A step of forming a metal layer made of a material that can be selectively etched with the second sacrificial layer for forming a diaphragm so as to cover each layer, and etching from the back surface side of the substrate,
A hole reaching the first sacrificial layer on the front surface side of the substrate is formed, the first sacrificial layer is selectively etched with respect to the first and second insulating layers through the hole, and then the hole is formed. Removing the resist wall, and further etching and removing the second sacrificial layer selectively with respect to both the first and second metal layers through a slit formed by removing the resist wall; The method is characterized by including a step of patterning the two metal layers to form a diaphragm having a predetermined shape.

[0024]

The ink jet head according to the first aspect is driven as follows. That is, the ink chamber is filled with ink in advance during operation. Then, during the heating period, the heater layer is energized to generate heat. When the buckling body receives the heat of the heater layer, it undergoes thermal expansion from the non-displaced state to the buckled state in which it buckles. As a result, the pressure generating member including the buckling member and the heater layer is deformed as a whole, and pressure is generated in the ink chamber. Due to this pressure, the ink liquid in the ink chamber is ejected to the outside through the nozzle opening of the nozzle plate. When the cooling period starts, the energization of the heater layer is stopped. Then
The buckling body is cooled and returns to the original non-displacement state together with the heater layer. As a result, the pressure generating member returns to its original position as a whole. The heating period and the cooling period are repeated, and the displacement and the return of the pressure generating member are repeated.

In this ink jet head, the substrate exists on the side of the pressure generating member opposite to the nozzle plate (hereinafter referred to as "back side"). As a material of this substrate, in fact, a material having a thermal conductivity higher than that of the ink by one digit or more can be easily selected. In this case, when the cooling period is entered after the heating period ends, the heat of the pressure generating member, particularly the buckling member and the heater layer, is rapidly released to the outside of the ink chamber through the substrate. Therefore, the cooling rate of the pressure generating member is increased. As a result, the response characteristics are improved,
High-speed printing is possible. Moreover, since the buckling body and the heater layer that form the pressure generating member are separate layers, the shape of the heater layer can be formed in an elongated pattern regardless of the shape of the buckling body. In this case, the energization amount for obtaining the necessary heat generation amount is small, and the power consumption is reduced.

The ink jet head according to claim 2 is driven as follows. That is, the ink chamber is filled with ink in advance during operation. Then, during the heating period, the buckling body is energized to generate heat. Due to this heat, the buckling body
The non-displaced state thermally expands and becomes a buckled buckled state. Nozzle plate side surface of the buckling body (hereinafter referred to as "surface")
Since the diaphragm provided along with is made of a flexible material, it flexes and deforms according to the pressing force due to the deformation of the buckling body. That is, the pressure generating member including the buckling member and the diaphragm is deformed as a whole. As a result, pressure is generated in the ink chamber. Due to this pressure, the ink liquid in the ink chamber is ejected to the outside through the nozzle opening of the nozzle plate. When the cooling period starts, the energization of the heater layer is stopped. Then, the buckling body is cooled and returns to the original non-displacement state. Since the diaphragm loses the pressing force from the buckling body, it returns to its original state by its own restoring force. That is, the pressure generating member returns to its original position as a whole. The heating period and the cooling period are repeated, and the displacement and the return of the pressure generating member are repeated.

According to this ink jet head,
Similarly, there is a substrate on the back side of the pressure generating member. As a material of this substrate, in fact, a material having a thermal conductivity higher than that of the ink by one digit or more can be easily selected.
In this case, when the cooling period is entered after the heating period ends, the heat of the pressure generating member, particularly the buckling member, is rapidly released to the outside of the ink chamber through the substrate. Therefore, the cooling rate of the pressure generating member is increased. As a result, the response characteristics are improved and high-speed printing becomes possible. Further, thanks to the diaphragm, the ink existing in the gap between the nozzle plate and the pressure generating member (diaphragm) is prevented from flowing around to the back side of the pressure generating member (diaphragm) during operation.
Therefore, the ejection force and the ejection speed of the ink are increased.
In addition, since the buckling body and the diaphragm that form the pressure generating member are separate bodies, the shape of the buckling body can be formed regardless of the shape of the diaphragm. For example, it becomes possible to provide a slit in the buckling body. In this case, as will be described later, it becomes possible to rapidly cool the buckling body by circulating a refrigerant such as ink through the buckling body on the back side of the diaphragm. Therefore, the response characteristic is further improved, and high-speed printing becomes possible.

The ink jet head according to claim 3 is driven as follows. That is, the ink chamber is filled with ink in advance during operation. Then, during the heating period, the heater layer is energized to generate heat. When the buckling body receives the heat of the heater layer, it undergoes thermal expansion from the non-displaced state to the buckled state in which it buckles. As a result, the pressure generating member including the buckling member, the heater layer, and the diaphragm is deformed as a whole, and pressure is generated in the ink chamber. Due to this pressure, the ink liquid in the ink chamber is ejected to the outside through the nozzle opening of the nozzle plate. When the cooling period starts, the energization of the heater layer is stopped. Then, the buckling body is cooled and returns to the original non-displacement state together with the heater layer. Since the diaphragm loses the pressing force from the buckling body, it returns to its original state by its own restoring force. As a result, the pressure generating member returns to its original position as a whole. The heating period and the cooling period are repeated, and the displacement and the return of the pressure generating member are repeated.

In this ink jet head, the substrate exists on the back side of the pressure generating member as in the first and second aspects. As a material of this substrate, in fact, a material having a thermal conductivity higher than that of the ink by one digit or more can be easily selected. In this case, when the cooling period is entered after the heating period ends, the heat of the pressure generating member, particularly the buckling member and the heater layer, is rapidly released to the outside of the ink chamber through the substrate.
Therefore, the cooling rate of the pressure generating member is increased. As a result, the response characteristics are improved and high-speed printing becomes possible. It should be noted that this situation does not change even if there is some ink layer between the substrate and the pressure generating member. In addition, claim 1
Similarly, since the buckling body forming the pressure generating member and the heater layer are separate layers, the heater layer can be formed in an elongated pattern regardless of the shape of the buckling body. In this case, the energization amount for obtaining the necessary heat generation amount is small, and the power consumption is reduced. Further, similarly to the second aspect, the diaphragm prevents the ink existing in the gap between the nozzle plate and the pressure generating member (diaphragm) from flowing around to the back side of the pressure generating member (diaphragm) during operation. Therefore, the ejection force and the ejection speed of the ink are increased. As a result, practical operating characteristics can be obtained. In addition, since the buckling body and the diaphragm forming the pressure generating member are separate bodies, the shape of the buckling body is
It can be formed independently of the shape of the diaphragm. For example, it becomes possible to provide a slit in the buckling body. In this case, as will be described later, it is possible to rapidly cool the buckling body and the heater layer by circulating a refrigerant such as ink through the buckling body on the back side of the diaphragm. Therefore, the response characteristic is further improved, and high-speed printing becomes possible.

In the ink jet head of the present invention, the heater layer is provided along the surface of the buckling body on the side of the substrate (hereinafter referred to as "rear surface"), so that the heating period ends. After that, in the cooling period, the heater layer, which has a particularly high temperature in the pressure generating member, is rapidly cooled through the substrate. Therefore, the cooling rate of the pressure generating member is further increased. As a result, the response characteristics are further improved,
High-speed printing is possible.

In the ink jet head of the fifth aspect, the pressure generating member has the first insulating layer provided between the substrate and the heater layer, so that there is a gap between the substrate and the heater layer. It is well insulated and the current flowing through the heater layer does not leak to the substrate. Therefore, the energization amount for obtaining the required heat generation amount is small, and the power consumption is reduced.

In the ink jet head of the sixth aspect, the pressure generating member has the second insulating layer provided between the buckling body and the heater layer, so that the buckling body and the heater layer are provided. Is well insulated, and the current flowing through the heater layer does not leak to the buckling body. Therefore, the energization amount for obtaining the required heat generation amount is small, and the power consumption is reduced.

In the ink jet head of the seventh aspect, since the diaphragm is formed in a substantially disc shape, the surface area of the diaphragm is small, but the ink chamber (the gap between the nozzle plate and the pressure generating member) is small. Volume change amount becomes large. This is because no matter how large the surface area of the diaphragm is, the displacement by being pushed by the buckling body is limited to the circular region centered on the position where the buckling body abuts. For example, when the diaphragm is formed in a rectangular plate shape, the vicinity of the rectangular corner portion is not displaced, and the vicinity of the corner portion does not contribute to the volume change of the ink chamber. On the other hand, when the diaphragm is formed in a substantially circular plate shape, the substantially entire surface of the diaphragm contributes to the volume change of the ink chamber. Therefore, as described above, the volume change amount of the ink chamber is large despite the small surface area of the diaphragm. As a result, although the surface area of the diaphragm is small, the ejection force and the ejection speed of the ink are large. Conversely, when the ink ejection force has a margin, the ink jet head can be downsized by reducing the diameter of the diaphragm.

In the ink jet head of the eighth aspect, at least a part of the diaphragm other than the peripheral portion is connected to the buckling member, so that after the heating period ends, the cooling period starts and the buckling member returns to its original position. When the diaphragm is returned to, the diaphragm receives the pulling force from the buckling body in addition to its restoring force. As a result, the diaphragm returns to its original position more quickly. Therefore, the response characteristic of the pressure generating member is improved, and high-speed printing becomes possible.

In the ink jet head of the ninth aspect, since the central portion of the diaphragm is connected to the central portion of the buckling body, the portion (central portion) of the diaphragm that has been displaced most during the heating period. During the cooling period, the buckling body is pulled by the fastest returning portion (central portion). As a result, the diaphragm returns to its original position even faster. Therefore, the response characteristic of the pressure generating member is further improved, and high-speed printing becomes possible.

In the ink jet head of claim 10,
A gap is provided between the buckling body and an intermediate portion between the peripheral portion of the diaphragm and a portion connected to the buckling body. Therefore, on the back side of the diaphragm, it is possible to rapidly cool the buckling body by causing a coolant such as ink to flow through the gap between the diaphragm and the buckling body. Therefore, the response characteristic is further improved, and high-speed printing becomes possible.

In the ink jet head of claim 11,
A gap is provided between the substrate and a portion of the pressure generating member located inside the peripheral portion of the buckling member and the substrate. Therefore, on the back side of the diaphragm, the buckling body and the heater layer can be rapidly cooled by causing a coolant such as ink to flow in the gap between the buckling body and the substrate. Therefore, the response characteristic is further improved, and high-speed printing becomes possible.

According to the ink jet head of claim 12,
Since the distance between the substrate and the portion of the pressure generating member is set within the range of 0.05 μm to 2.0 μm, the gap between the substrate and the pressure generating member can be easily formed. , The response characteristics of the pressure generating member are maintained well. That is, when the distance of the gap is 0.05 μm or more, the sacrificial layer (processing layer) and the material of the pressure generating member are sequentially stacked on the substrate, and the sacrificial layer is removed by an etching solution. The gap can be formed. On the other hand, the gap distance is 0.05
If it is less than μm, it becomes difficult to infiltrate the etching liquid into the gap, and it becomes difficult to form the gap. Also,
When the distance of the gap is 2.0 μm or less, the heat of the pressure generating member, particularly the buckling member and the heater layer, can be rapidly released to the outside of the ink chamber during the cooling period through the substrate. Therefore,
The response characteristics of the pressure generating member are maintained well. On the other hand, when the distance of the gap exceeds 2.0 μm, the effect of heat radiation through the substrate is reduced, and the response characteristic of the pressure generating member is significantly deteriorated.

In the ink jet head of claim 13,
A slit penetrating from a surface facing the substrate to a surface of the buckling body on the diaphragm side is provided in a portion of the pressure generating member that is inside the peripheral portion of the buckling body. Therefore, on the back side of the diaphragm, it is possible to rapidly cool the buckling body by circulating a coolant such as ink through the slit. In particular, when there are gaps between the diaphragm and the buckling member or between the substrate and the pressure generating member, these gaps communicate with each other through the slits, so that the cooling effect is further enhanced. Therefore, the response characteristic is further improved, and high-speed printing becomes possible.

In the ink jet head of claim 14,
A plurality of the slits are provided, and a belt-shaped portion of the buckling body sandwiched by the slits buckles. At this time, for example, by attaching the peripheral portion of the buckling body to the entire circumference of the substrate, the thermal stress of the buckling portion due to repeated heating and cooling can be received in the entire peripheral portion. That is, the thermal stress of the strip-shaped portion sandwiched by the slits is outwardly generated in one direction in the extending direction of the strip-shaped portion. This outward force in one direction is applied to the specific portion of the peripheral portion, but is also received by the portion of the peripheral portion adjacent to the specific portion. Therefore, the thermal stress of the buckling portion is not applied only to a specific portion, and the entire peripheral portion can be relaxed and received. Therefore, the attachment position of the substrate and the buckling body is less likely to be damaged, and the life of the inkjet head is extended.

In the ink jet head of claim 15,
Since the substrate is provided with a refrigerant circulation hole that penetrates the substrate and faces a portion of the pressure generating member located inside the peripheral portion of the buckling body, the refrigerant circulation hole is formed. Through, the coolant such as ink can be supplied from the side of the substrate opposite to the pressure generating member (hereinafter referred to as “back side”) to the pressure generating member side of the substrate (hereinafter referred to as “front side”). The supplied coolant flows between the front side and the back side of the substrate as the pressure generating member is displaced and returned by heating and cooling. Therefore, the pressure generating member can be rapidly cooled. This is especially significant when the diaphragm is provided and ink does not wrap around to the back side of the diaphragm. Further, when there is a gap between the diaphragm and the buckling member, or between the substrate and the pressure generating member, further in the portion of the pressure generating member inside the peripheral portion of the buckling member, When a slit is provided that penetrates from the surface facing the substrate to the surface of the buckling body on the diaphragm side, the refrigerant flows through these gaps and slits, so that the cooling effect is further enhanced. Therefore, the response characteristic is further improved, and high-speed printing becomes possible.

In the ink jet head of claim 16,
Since the hole for refrigerant circulation is gradually reduced in size from the back side of the substrate toward the front side, as compared with the case where the hole for refrigerant circulation is not present, the facing area between the pressure generating member and the substrate surface is It does not decrease much. Therefore, when the cooling period is entered after the end of the heating period, the heat of the pressure generating member, particularly the buckling member, is rapidly released to the outside of the ink chamber through the substrate. Therefore, the cooling rate of the pressure generating member is kept high, and the response characteristic is kept good.

In the ink jet head of claim 17,
Since a coolant reservoir communicating with the coolant circulation hole is formed on the back side of the substrate, a coolant such as ink can be supplied from the coolant reservoir to the front side of the substrate through the coolant circulation hole.

According to the ink jet head manufacturing method of the eighteenth aspect, since the pressure generating member can be manufactured by the semiconductor integrated process, the ink jet head can be manufactured in a small size. Further, the first sacrificial layer and the second sacrificial layer are continuously etched to form two gaps, a gap between the substrate and the pressure generating member and a gap between the buckling body and the diaphragm in the pressure generating member. Then, it can be collectively formed. Therefore, the manufacturing process can be simplified. Moreover, since the two gaps are formed in accordance with the thicknesses of the first sacrificial layer and the second sacrificial layer, the distances between the gaps can be set accurately.

[0045]

EXAMPLES Hereinafter, the ink jet head of the present invention and the method for manufacturing the same will be described in detail with reference to examples.

FIG. 1 shows the overall construction of an ink jet head 90 of one embodiment. The inkjet head 90 includes a substrate 7 including the surface protective film 6. On the front surface side of the substrate 7, the first insulating film 2 as a first insulating layer is formed.
A heater layer 3 and a second insulating film 4 as a second insulating layer.
The buckling body 1 and the diaphragm 5 are provided in this order. The first insulating film 2, the heater layer 3, and the second insulating film 4
And the buckling member 1 and the diaphragm 5, the pressure generating member 20.
Is composed. The diaphragm 5 is provided on the front surface side of the substrate 7.
The nozzle plate 10 is attached via a spacer 8 so as to face the. Electrode pads 1 are provided on both sides of the buckling body 1.
3a and 13b are provided. On the other hand, a casing 9 is provided on the back side of the substrate 7, and the casing 9 forms a coolant reservoir 34 on the back side of the substrate 7.

FIG. 3 is a perspective view of the ink jet head in a disassembled state, and FIG. 4 is a buckling body 1,
The first insulating film 2, the heater layer 3 and the second
The insulating film 4 (not shown in FIG. 3) is shown.
3 and 4, for convenience, the substrate 7, the buckling member 1, the first
Although each of the insulating film 2 and the second insulating film 4 is shown in a rectangular shape, in reality, they can be extended (except the regions of the electrode pads 13a and 13b).

As shown in FIG. 3, the substrate 7 is made of a silicon (Si) plate having a silicon oxide film formed by thermal oxidation as the surface protection film 6 in this example. The thermal conductivity of this substrate 7 is about 70 W · m ⁻¹ · K ⁻¹ . The film thickness of the surface protection film 6 is preferably thick to secure the insulation property, but is preferably thin for heat conduction. In the end, the film thickness of the surface protection film 6 is within the range of 0.5 to 1 μm. Is set to. A coolant circulation hole 16 is formed substantially in the center of the substrate 7. The coolant circulation hole 16 is a hole having a rectangular cross section that penetrates the substrate 7. The dimensions (cross-sectional dimensions) of the sides of the rectangle of the coolant circulation hole 16 are gradually reduced from the back side of the substrate 7 toward the front side. Is set to. The reason for this is that the area where the pressure generating member 20, particularly the buckling member 1 or the heater layer 3, and the surface of the substrate 7 face each other is not reduced as much as possible, as compared with the case where the holes for circulating the refrigerant do not exist. Since the pressure generating member 20 and the substrate 7 are opposed to each other over a wide area in this manner, the heat of the pressure generating member 20, particularly the buckling member 1 and the heater layer 3 during operation is efficiently transferred to the outside of the ink chamber through the substrate 7. It is possible to release.

The buckling member 1 is made of a metallic material (having a thickness T) such as nickel. More specifically, the buckling body 1 is made of tantalum having a small linear expansion coefficient of 0.01 μm on the substrate 7 side so that the buckling body 1 is deformed toward the nozzle plate 10 side when it is about to buckle due to thermal expansion.
It has a two-layer structure in which nickel having a large linear expansion coefficient and a thickness of 6 μm is arranged on the side.

The first insulating film 2 and the second insulating film 4 (FIG. 4) are made of an insulating material such as silicon oxide or alumina. First insulating film 3 and second insulating film 4
Thereby, the current flowing through the heater layer 3 can be prevented from leaking to the substrate 7 and the buckling body 1, and the power consumption can be reduced.

As shown in FIG. 4, the buckling body 1, the first insulating film 2 and the second insulating film 4 are provided with four "V" -shaped slits 40 penetrating these rectangular surfaces. ing.
The four slits 40 are arranged so as to be spaced apart from each other with the bent portion of the "U" facing the central portion. As a result, cross-shaped portions 2a, 4a and 1a are formed in the centers of the first insulating film 2, the second insulating film 4 and the buckling body 1. In particular, each side 1b of the cross portion 1a of the buckling body 1
The end (having a length L and a width W) is supported by the peripheral edge portion 1c of the buckling body 1, and each side 1b of the cross portion 1a actually buckles when heated. According to the shape of the buckling body 1, by attaching the peripheral edge portion 1c to the substrate 7 over the entire circumference, thermal stress of the buckling portion 1b due to repeated heating and cooling can be received by the entire peripheral edge portion 1c. . That is, the thermal stress on each side 1b of the cross portion 1a is generated outward in the longitudinal direction. This thermal stress is applied to a portion of the peripheral edge portion 1c that is connected to each side 1b, but is also received by the portion of the peripheral edge portion 1c adjacent to that position. Therefore, the thermal stress on each side 1b of the cross portion 1a can be relaxed and received by the entire peripheral portion 1c. Therefore, the attachment portion between the substrate 7 and the buckling body 1 is less likely to be damaged, and the life of the inkjet head can be extended.

The heater layer 3 is made of a material such as nickel or nickel-chromium alloy. The heater layer 3 includes strip-shaped electrode portions 3c and 3c extending in parallel along the periphery of the first and second insulating films 2 and 3 and cross portions 2a and 4a of the first and second insulating films 2 and 4. The circular portion 3a sandwiched between the central portions (intersections of the sides 1b) of the
Sandwiched between the sides 1b of the cross portions 2a and 4a of the insulating films 2 and 4,
It has a strip-shaped resistance portion 3b which connects the electrode portions 3c, 3c and the circular portion 3a by meandering in a U-shape. On the electrode portions 3c, 3c, electrode pads 13a, 13b made of the same layer as the buckling body 1 are connected.
As described above, since the buckling body 1 and the heater layer 3 forming the pressure generating member 20 are separate layers, the heater layer 3 should be formed in an elongated pattern regardless of the shape of the buckling body 1. You can Therefore, it is possible to reduce the energization amount for obtaining the required heat generation amount, and it is possible to reduce the power consumption.

As shown in FIG. 3, the diaphragm 5 is made of an elastic material such as nickel and is formed in a substantially disc shape (having a diameter E). Thanks to the diaphragm 5, the ink 15 existing in the gap 31 between the nozzle plate 10 and the pressure generating member 20 shown in FIG. 1 can be prevented from flowing around to the back side of the pressure generating member 20 during operation. Therefore, the ejection force and ejection speed of the ink can be increased, and as a result, practical operating characteristics can be obtained. In particular, since the diaphragm 5 is formed in a substantially disc shape, the volume change amount of the ink chamber (gap) 31 becomes large despite the small surface area of the diaphragm 5. This is because no matter how large the surface area of the diaphragm is, it is pushed and displaced by the buckling body 1 only in the circular region centered on the position where the buckling body 1 abuts. As a result, although the surface area of the diaphragm 5 is small, the ink ejection force and ejection speed can be increased.

The spacer 8 is made of an insulating film material such as polyimide or acrylic photosensitive adhesive having a predetermined thickness. This spacer 8 has a diaphragm 5
A circular through hole 8a is provided in order to form a gap 31 that should be filled with ink between the nozzle plate 10 and the nozzle plate 10. Further, in order to supply the ink into the gap 31,
An ink supply passage 14 is formed which penetrates the spacer insulating film with a predetermined width in the thickness direction and communicates from the film end portion into the through hole 8a.

The nozzle plate 10 has a thickness of 0.2, for example.
mm of glass or plastic sheet material. A nozzle orifice 11 serving as a nozzle opening is formed substantially in the center of the nozzle plate 10. The nozzle orifice 11 is a hole having a circular cross section that penetrates the nozzle plate 10. The inner diameter of the nozzle orifice 11 is set so as to gradually decrease from the back side of the nozzle plate 10 toward the front side.

As shown in FIG. 1, in the completed state, the first
Insulating film 2, heater layer 3, second insulating film 4, and buckling body 1
Are intimately close to each other. Then, only the respective peripheral portions (in FIG. 1, the portions forming both ends of the peripheral portion in one direction are shown) are provided on the substrate 7 (surface protective film 6).
Is attached to the substrate 7 and is supported by the substrate 7. The first insulating film 2, the heater layer 3, the second insulating film 4, and the portion of the buckling body 1 inside the peripheral portion are separated from the substrate 7, and the surface protection film 6 of the substrate 7 and the first insulating film are separated from each other. A gap 32 is formed between the membrane 2 and a portion inside the peripheral portion.
Are formed. The gap 32 communicates with the coolant reservoir 34 through the coolant circulation hole 16. Also, the electrode pad 1
3a and 13b are located outside the spacer 8, that is, outside the ink chamber. The electrode pad 13a is connected to the switch 52 via the wiring 51a. This switch is adapted to switch between the power supply 12 and the ground. The electrode pad 13b is connected to the ground via the wiring 51b.

The central portion 5a and the peripheral portion 5c of the diaphragm 5 are projected or bent toward the buckling body 1, and the central portion 5a is attached to and supported by the central portion 1a of the buckling body 1. The peripheral edge portion 5c of the diaphragm 5 is attached to the peripheral edge portion 1c of the buckling body 1. That is, it is attached to the substrate 7 together with the first insulating film 2, the heater layer 3, the second insulating film 4, and the peripheral portion of the buckling body 1, and is supported by the substrate 7. Intermediate part 5b (center part 5) of diaphragm 5
The portion between a and the peripheral portion 5c) is separated from the buckling body 1, and a gap 33 is formed between the buckling body 1 and the intermediate portion 5b of the diaphragm 5. The gap 33 communicates with the gap 32 between the surface protection film 6 of the substrate 7 and the first insulating film 2 through the slit 40 shown in FIG. 4, and further through the coolant circulation hole 16 with the coolant reservoir 34. It is in communication.
In this way, since the buckling body 1 and the diaphragm 5 that form the pressure generating member 20 are separate bodies, the shape of the buckling body 1 and the shape of the diaphragm 5 are freely restricted without being restricted to each other. Can be designed.

In the ink jet head 90, the ink supply passage 14 connected to the ink chamber (gap) 31.
The refrigerant supply path 35 connected to the refrigerant reservoir 34 is branched from one ink supply path (not shown). Therefore, the ink 15 supplied to the ink chamber 31
Is also supplied to the refrigerant reservoir 34 as a refrigerant. The thermal conductivity of this ink 15 is general,
It is about 0.5 W · m ⁻¹ · K ⁻¹ .

This inkjet head is driven as follows.

In operation, as shown in FIG. 1, the ink 15 is previously supplied to the gap 31 between the nozzle plate 10 and the diaphragm 5 through the ink supply passage 14. Further, the ink 15 as a refrigerant is supplied to the refrigerant reservoir 34 through the refrigerant supply passage 35. The ink 15 supplied to the coolant reservoir 34 is supplied to the gap 32 between the substrate 7 and the second insulating film 2 through the coolant circulation hole 16, and further the slit 40.
(See FIGS. 3 and 4) Through buckling body 1 and diaphragm 5
It is supplied to the gap 33 between. As a result, the entire ink chamber is filled with the ink 15.

Next, the switch 52 is switched to the power source 12 side, a voltage is applied between the electrodes 13a and 13b, and the heater layer 3 is energized to generate heat (heating period). Each side 1b of the cross portion 1a of the buckling body 1 has a strip-shaped resistance portion 3b of the heater layer 3.
In response to the heat of, the non-displaced state thermally expands and tries to extend in the longitudinal direction. However, since both ends (peripheral edges) 1c of the buckling body 1 in the longitudinal direction are fixed to the substrate 7, the buckling body 1 cannot extend in the longitudinal direction. Therefore, the compressive force P ₀ is generated and accumulated inside the buckling body 1 as its reaction. When this compressive force P ₀ exceeds the buckling load, the buckling body 1 buckles, as shown in FIG.
A is in a buckling state in which a is displaced toward the nozzle plate 10.
The displacement to the nozzle plate 10 side is mainly because the buckling body 1 has a two-layer structure in which tantalum is arranged on the substrate 7 side and nickel is arranged on the nozzle plate 10 side. Moreover, the temperature of the substrate 7 side becomes lower than that of the nozzle plate 10 side due to the heat radiation effect of the substrate 7. As a result of buckling of the buckling body 1, the pressure generating member 20 including the buckling body 1, the heater layer 3, and the diaphragm 5 is deformed as a whole, and pressure is generated in the ink chamber (gap) 31. Due to this pressure, the ink chamber 31
The ink liquid 15 inside is ejected to the outside as ink droplets 15a through the nozzle orifice 11 of the nozzle plate 10. By the ejection of the ink droplets 15a, printing is performed on the print surface provided facing the nozzle plate 10.

At the same time that the buckling member 1 and the diaphragm 5 are displaced toward the nozzle plate 10 side, the ink 15 existing in the coolant reservoir 34 passes through the coolant circulation hole 16 between the substrate 7 and the first insulating film 2. Of the buckling body 1 and the diaphragm 5 through the slit 40.

Next, the switch 52 is returned to the ground side to stop energizing the heater layer (cooling period). Then, the buckling body 1 is cooled and tries to return to the original non-displacement state together with the heater layer 3. When the buckling body 1 tries to return to its original position, the diaphragm 5 receives a pulling force from the buckling body 1 in addition to its own restoring force. Particularly, since the central portion 5a of the diaphragm 5 is connected to the central portion 1a of the buckling body 1, the portion (central portion) 5a of the diaphragm 5 that has been displaced most during the heating period is Of these, the portion (center portion) 1a that returns the fastest is pulled. As a result, the diaphragm 5 quickly returns to its original position. As a result, the pressure generating member 20
Returns to its original position as a whole (standby state). The heating period and the cooling period are repeated, and the displacement and the return of the pressure generating member 20 are repeated.

Here, the coolant that has flowed into the gaps 32 and 33 and the slit 40 through the coolant circulation hole 16 as described above moves between the front side and the back side of the substrate 7 as the pressure generating member 20 is displaced and returned by heating and cooling. It flows between and contributes to the release of heat. Moreover, in this ink jet head 90, the substrate 7 exists on the back side of the pressure generating member 20. This board 7
The thermal conductivity of the ink is larger than that of the ink 15 by two digits or more, and is about 70 W · m ⁻¹ · K ⁻¹ . Therefore, when the cooling period is entered after the end of the heating period, the heat of the buckling body 1 and the heater layer 3 is rapidly released to the outside of the ink chamber through the substrate 7 (including the surface protective film 6). Therefore, the pressure generating member 20, particularly the buckling body 1 and the heater layer 3, can be cooled more rapidly. As a result, the response characteristics are improved,
High-speed printing is possible.

Next, the results of examining the performance of the ink jet head 90 by simulation will be described.

(1) First, the ink jet head 9
A simulation was performed on the amount of displacement and the temperature rise of the central portion 5a of the diaphragm 5 at 0.

FIG. 6 shows a schematic structure of the apparatus used for this simulation. In this device, a portion 91 involved in the thermal response characteristic of the inkjet head 90 is housed in a container 99 for giving a boundary condition in this simulation. The size of the container 99 is set to be larger by 20 μm than the outer shape of the portion 91 related to the thermal response characteristic. As the shape of the portion 91 involved in the thermal response characteristic, which serves as a reference for setting the dimensions of the container 99, when the temperature of the buckling body 1 rises by 100 deg, the buckling body 1 is deformed by 9 μm toward the nozzle plate 10 side. A shape in which the central portion 1a of the body 1 is displaced by an average of 4.5 μm is adopted. The temperature rise is set to 100 deg because the energy required for the ink droplet to be ejected by another energy calculation is the “kinetic energy + surface energy” of the ink droplet.
This is because it is set as ten times. The simulation was performed on the assumption that the container 99 was filled with the ink 15 and the inner surface of the container 99 and the back surface of the substrate 7 were kept at 0 ° C. Figure 6
Inside, the arrow from the heater layer 3 to the back side of the substrate 7 indicates the main heat discharge path.

FIG. 5 shows the results of this simulation.
It shows how to set the parameters for the thermal response characteristic part 91. A represents the distance of the gap 32, that is, the distance between the surface protective film 6 of the substrate 7 and the first insulating film 2. B represents the thickness of the first insulating film 2, and C represents the thickness of the second insulating film 4. Further, D represents the distance of the gap 33, that is, the distance between the buckling body 1 and the diaphragm 5.

The length L of each side 1b of the buckling body 1 shown in FIG. 4 (excluding the central intersection of the cross portion 1a) is set to 250 μm. The width W of the buckling body 1 was 92 μm, and the thickness T was 5 μm. Further, in FIG. 4, the number of sides 1b of the buckling body 1 (the number of buckling portions) is four, but this simulation was performed assuming that there are eight radially. The diameter E of the diaphragm was 800 μm, and the thickness of the heater layer 3 was 0.1 μm.

(I) First, the parameter A is 0.5 μm and B
Was 0.5 μm, C was 0.5 μm, and D was 0.5 μm.

As the driving condition, the energy consumption per unit volume of the buckling body 1 is 7.6 × 10 ⁸ J /
m ³ , power consumption per unit volume was set to 4 × 10 ¹³ W / m ³ , and pulse width was set to 19 μs (driving condition 1).

FIG. 7A shows drive waveforms corresponding to the drive condition 1. Further, FIG. 7B shows a time course of the displacement amount ΔZ and the rising temperature ΔT of the central portion 1a of the buckling body 1 under the driving condition 1 by the simulation calculation. In addition, the time course of the temperature rise ΔT _INK of the ink present on the surface of the diaphragm 5 is also shown. When the response speed is calculated from the rising temperature curve ΔT of the buckling body 1, the rising response speed (tr) is 19 μs and the falling response speed (td) is 101 μs. Therefore,
It can be seen that driving at a driving frequency of 8.3 kHz is possible.

The reason why the drive frequency can be increased in this way is that the falling response speed (td) is relatively fast. That is, the heat of the buckling body 1 and the heater 3 is
The ink 15 flowing in and out through the coolant circulation hole 16 between the substrate 2 and the back side of the substrate 7 and the substrate 7 having the surface protective film 6 are quickly discharged to the outside. Further, the substrate 7 having high thermal conductivity is arranged near the buckling body 1. As a result, the falling response speed (td) can be increased and the drive frequency can be increased.

(Ii) Next, under the same driving condition 1, parameter B is 0.5 μm, C is 0.5 μm, and D is 0.5 μm.
The value of A was changed from 0.1 to 2.0 μm.

FIG. 8A shows the change in response speed at this time. The rising response speed (tr) becomes slightly faster as A becomes larger. On the other hand, the falling response speed (td) becomes significantly slower as A increases. As can be seen from FIG. 8A, when A is 2 μm or less, driving at a driving frequency of 5.5 kHz becomes possible. When A is 1 μm or less, the driving frequency is 6.8 kHz.
Can be driven.

The parameter A, that is, the distance of the gap 32 is set practically within the range of 0.05 μm to 2.0 μm. The reason is that the distance of the gap 32 is 0.05.
If it is at least μm, as will be described later, a sacrificial layer (processing layer) and a material of the pressure generating member 20 are sequentially laminated on the substrate 7, and the sacrificial layer is removed by an etching solution to remove the gap. This is because 32 can be easily formed.
On the other hand, if the distance of the gap 32 is less than 0.05 μm, it becomes difficult to infiltrate the etching liquid into the gap 32, and it becomes difficult to form the gap 32. Further, if the distance of the gap 32 exceeds 2.0 μm, as can be seen from this simulation, the effect of heat radiation through the substrate 7 is reduced, and the response characteristic of the pressure generating member 20 is not improved.

(Iii) Next, under the same driving condition 1, the parameter A is 0.5 μm, C is 0.5 μm, and D is 0.5 μm.
While maintaining m, B was changed from 0.1 to 1.0 μm.

FIG. 8B shows the change in response speed at this time. The rising response speed (tr) becomes slightly faster as B becomes larger. On the other hand, the falling response speed (td) becomes significantly slower as B increases. As can be seen from FIG. 8B, when B is 1 μm or less, driving at a driving frequency of 7.6 kHz is possible. When B is 0.5 μm or less, the driving frequency is 8.3 k.
Driving at Hz becomes possible. The parameter B, that is, the thickness of the first insulating film 2 can be actually set to 0.1 μm or less.

(Iv) Next, under the same driving condition 1, parameter A is 0.5 μm, B is 0.5 μm, and D is 0.5 μm.
While maintaining m, C was changed from 0.1 to 1.0 μm.

FIG. 9A shows the change in response speed at this time. The rising response speed (tr) becomes slightly slower as C increases. The falling response speed (td) also becomes slightly slower as C increases. As can be seen from FIG. 9 (a), when C is 1 μm or less,
It becomes possible to drive at a drive frequency of 8 kHz. When C is 0.5 μm or less, driving at a driving frequency of 8.3 kHz becomes possible. The parameter C, that is, the second
The thickness of the insulating film 4 may actually be 0.1 μm or less.

(V) Next, under the same driving condition 1, the parameter A is 0.5 μm, B is 0.5 μm, and C is 0.5 μm.
While maintaining m, D was changed from 0.1 to 2.0 μm.

FIG. 9B shows the change in response speed at this time. The rising response speed (tr) increases as D increases. Also, the fall response speed (t
d) becomes significantly faster as D increases. As can be seen from FIG. 9B, when D is 0.1 μm, driving at a driving frequency of 6.7 kHz is possible. Also, D
Is 0.5 μm, the driving can be performed at a driving frequency of 8.3 kHz. Especially when D is 1.0 μm or more,
Driving at a driving frequency of 10 kHz is possible. The parameter D, that is, the distance of the gap 33 between the buckling body 1 and the diaphragm 5 is actually 1.0 μm as described later.
The above can also be done.

(2) Next, the above ink jet head 9
The ejection speed V of the ink droplet of 0 was examined.

The ejection velocity V of the ink droplet can be calculated by a simulation based on fluid analysis. FIG. 10 is a plan view showing the inkjet head 90 modeled for fluid analysis, and FIG. 11 is a plan view of X ₂ in FIG.
Shows -X ₂ sectional view taken along the line. Note that the nozzle plate is omitted in FIG. 10 for convenience, and only the diaphragm 5 of the pressure generating member 20 is shown in FIG. 11.

In the simulation by the fluid analysis, a so-called wall drive model was used in which the movement velocity V _{0 of the} buckling body is applied to the fluid 15b on the surface of the diaphragm 5 and the movement of the fluid in the ink chamber 31 is analyzed. In this wall drive model, the diaphragm 5 is first displaced at the speed of V ₀ . As a result, the pressure generated on the surface of the diaphragm 5 propagates through the fluid 15 toward the nozzle plate 10.
By the propagation of this pressure, the ink droplet 15a is ejected from the nozzle orifice 11 at the velocity V. It should be noted that part of the pressure is propagated toward the coolant reservoir 34 through the ink supply passage 14 and the coolant supply passage 35 shown in FIG.

The ejection speed V was calculated by changing the length F, width G, and depth H of the ink supply path as parameters. Here, the driving condition 1 in the above (1) is adopted as the driving condition. Regarding the parameters shown in FIG. 5, A is 0.5 μm, B is 0.5 μm, and C is 0.5 μm.
m and D were 0.5 μm.

In FIG. 12A, the parameter G is 40 μm,
The change of the ejection speed V when H is 30 μm and F is changed from 200 μm to 1000 μm is shown. The ejection speed V becomes faster as the length H of the ink supply passage 14 becomes longer.

In FIG. 12B, the parameter F is set to 200 μm.
The change in the ejection speed V when m and H are set to 30 μm and G is changed from 30 μm to 60 μm is shown. The ejection speed V becomes slower as the width G of the ink supply passage 14 becomes wider.

In FIG. 12C, the parameter F is set to 200 μm.
The change in the ejection speed V when m and G are 40 μm and H is changed from 20 μm to 50 μm is shown. The ejection speed V becomes slower as the depth H of the ink supply passage 14 becomes deeper.

That is, as the length F of the ink supply path 14 is longer and the opening area (G × H) is narrower, that is, the resistance when the ink 15 tries to flow back through the ink supply path 14 is larger, the ink The discharge speed V is high. Here, from the result of FIG. 12, the length F of the ink supply path 14 is 200 μm or more, and the opening area (G × H) is 2
If it is less than 000 μm ² , the ink droplet 15a is 6.7 m.
It was found that discharge was performed at a speed of / s or more. In particular, the length F of the ink supply path 14 is 1000 μm, and the opening area (G ×
H) is 1200 μm ² , the ink droplet 15a has 1
Discharge at a speed of 5.6 m / s or more.

(3) Using the apparatus shown in FIG. 6 again, the diaphragm 5 in the ink jet head 90 is
A simulation was performed on the amount of displacement and the temperature rise of the central portion 5a.

Similar to the simulation of (1) (i) above, the length of each side 1b of the buckling body 1 shown in FIG.
L does not include the central intersection portion of a) was 250 μm. The width W of the buckling body 1 is set to 92 μm and the thickness T is set to 5 μm.
m. Further, in FIG. 4, the number of sides 1b of the buckling body 1 (the number of buckling portions) is four, but this simulation was performed assuming that there are eight radially. Further, the diameter E of the diaphragm is 800 μm, and the thickness of the heater layer 3 is 0.1 μm.
μm.

In addition, the parameter A shown in FIG.
μm, B 0.5 μm, C 0.5 μm, D 0.5 μm
m.

As driving conditions, the energy consumption per unit volume of the buckling body 1 is 7.6 × 10 ⁸ J /
m ³ , power consumption per unit volume was 8 × 10 ¹³ W / m ³ , and driving pulse width was set to 9.5 μs (driving condition 2). The drive condition 2 has the same energy consumption per unit volume as the drive condition 1, the power consumption is twice, and the pulse width is 1/2.

FIG. 13A shows drive waveforms corresponding to the drive condition 2. Further, FIG. 13B shows a time course of the displacement amount ΔZ and the rising temperature ΔT of the central portion 1a of the buckling body 1 under the driving condition 2 by the simulation calculation. In addition, the time course of the temperature rise ΔT _INK of the ink present on the surface of the diaphragm 5 is also shown. When the response speed is calculated from the temperature rise curve ΔT of the buckling body 1, the rising response speed (tr) is 9.5 μs and the falling response speed (td) is 101 μs. Therefore, it can be seen that the driving can be performed at the driving frequency of 9.0 kHz. In this driving condition 2, since the driving pulse width is shorter and the power consumption is larger than that of the driving condition 1, the moving speed of the buckling body 1 can be further increased, and the driving frequency can be increased. can do.

(4) Next, the ejection velocity V of the ink droplets of the ink jet head 90 under the driving condition 2 was calculated by a simulation by fluid analysis using the models shown in FIGS. 10 and 11.

Similar to the simulation of (2) above,
The ejection speed V was calculated by changing the length F, width G, and depth H of the ink supply path as parameters. Regarding the parameters shown in FIG. 5, A is 0.5 μm and B is B, respectively.
Was 0.5 μm, C was 0.5 μm, and D was 0.5 μm.

From the results of this simulation, when the length F of the ink supply path 14 is 200 μm or more and the opening area (G × H) is 2000 μm ² or less, the ink droplet 1
It was found that 5a was discharged at a speed of 22.9 m / s or more. In particular, the length F of the ink supply path 14 is 1000 μ
When m and the opening area (G × H) are 1200 μm ² , the ink droplet 15a is ejected at a speed of 31.8 m / s or more.
As described above, by adopting the driving condition 2, the ejection speed of the ink droplet 15a could be significantly improved.

The reason why the discharge speed V can be improved in this way is that the driving condition 2 makes the deformation speed of the buckling body 1 faster than that under the driving condition 1. That is, the driving condition 2 and the driving condition 1 have the same energy consumption per unit volume of the buckling body 1, but the driving condition 2 has a smaller driving pulse width than the driving condition 1 and consumes less energy. The power is large. Therefore, the deformation speed of the buckling body 1 is increased. As a result, the pressure on the ink 15b increases and the ejection speed V of the ink droplet 15a can be improved.

Thus, under the driving conditions, the buckling member 1
If the power consumption is doubled without changing the energy consumption per unit volume of, that is, if the driving pulse width is halved, the ejection speed of the ink droplet 15a can be 1.5 times.

(5) Next, in the simulation by the fluid analysis using the models shown in FIGS. 10 and 11, the power consumption per unit volume of the buckling body 1 in the driving condition is changed over a wide range to The ejection speed V of the ink droplets of the inkjet head 90 was calculated.

Regarding the parameters shown in FIG. 5, A is 0.5 μm, B is 0.5 μm, and C is 0.5 μm.
m and D were 0.5 μm. Also, FIG. 10 and FIG.
For the ink supply path 14 shown in FIG.
00 μm, G 40 μm, and H 30 μm.

FIG. 14 shows the ejection speed V of the ink droplets at this time. As can be seen from FIG. 14, when the power consumption W per unit volume of the buckling body 1 is less than 3 × 10 ¹³ W / m ^3, ink droplets are not ejected (or ejection is unstable), but power consumption is low. When W exceeds a threshold value of about 3 × 10 ¹³ W / m ³ , ejection is started, and the ejection speed V increases as the power consumption W increases. Therefore, in consideration of stable ejection and increase in ejection speed, it is desirable to set the power consumption W per unit volume of the buckling body 1 to 4 × 10 ¹³ W / m ³ or more.

Further, the discharge speed V can be increased by increasing the power consumption W per unit volume of the buckling body 1 in this manner, but if the energy consumption is increased more than necessary in order to increase the power consumption W. The temperature of the buckling body 1 becomes too high and deteriorates, resulting in a shorter life. From this perspective,
The energy consumption per unit volume of the buckling body 1 is preferably 4 × 10 ⁹ J / m ³ or less, more preferably 7.6 × 10 ⁸ J / m ³ or less. .

The material of the buckling body 1 is not limited to the above nickel. The buckling body 1 may be made of any material as long as it has a large Young's modulus, a large linear expansion coefficient, and is easy to form a film. The dimensions of the buckling portion 1b of the buckling body 1 are as follows: length L = 250 μm, W = 92 μm, thickness = T5 μ
It is not limited to m. Further, the number of buckling parts of the buckling body 1 is not limited to four or eight. The number of buckling portions may be two or six. By radially increasing the number of buckling portions, the pressure on the ink can be increased and the ejection speed of the ink droplets can be improved.

The diameter E of the diaphragm is 800 μm.
In addition, the thickness of the heater layer is not limited to 0.1 μm. The size may be such that the required energy can be produced without impairing the degree of integration and the dimensions are easy to manufacture.

Although the surface protection film 6 is a silicon oxide film, alumina may be provided instead. Since alumina has a higher thermal conductivity than the silicon oxide film, the cooling rate of the buckling body 1 can be increased and the response characteristics can be further improved.

The substrate 7 is made of silicon (S
i) Although the plate is used, any material having a thermal conductivity of about 70 W · m ⁻¹ · K ⁻¹ or more may be used, and for example, a glass plate may be used. In that case, the surface protective film 6 can be omitted.

The refrigerant supplied to the refrigerant reservoir 34 is not limited to the ink 15 and may be a liquid or sol substance having a thermal conductivity equal to or higher than that of the ink 15.

In this example, the ink jet head 90 having only one nozzle orifice 11 has been described, but in practice, the nozzle plate 10 has a plurality of nozzle orifices 11 and the pressure generating member 2 facing the nozzle orifices 11.
The ink 15a may be ejected from a plurality of positions on the nozzle plate 10 by arranging 0 and 0.

Next, a method of manufacturing the ink jet head 90 will be described.

15 to 20 show a process of manufacturing the pressure generating member 20, which is a main part of the ink jet head 90. The subdivisions (a), (b),…, in these figures
The left side (X) and the right side (Y) of (q) correspond to the X ₁ -X ₁ line cross section and the Y ₁ -Y ₁ line cross section in FIG. 3, respectively.

(I) First, as shown in FIG. 15 (a), the silicon oxide films 6 and 6B are formed on the front and back surfaces of the silicon substrate 7 at both sides (100) to a predetermined thickness (for example, by thermal oxidation). 1 μm).

(Ii) Next, as shown in FIG. 15B, a photoresist (not shown) is applied to the back surface of the substrate 7 and photolithography is performed to form the coolant circulation hole 16 in the resist. A rectangular opening corresponding to the shape (see FIG. 3) is formed. Then, dry etching is performed using CHF ₃ to form a rectangular opening 6a in the thermal oxide film 6 on the back surface side. Subsequently, the silicon substrate 7 is dipped in a potassium hydroxide solution, and wet etching is performed from the back surface side of the substrate 7 to the front surface side using the thermal oxide film 6 as a mask.
The coolant circulation hole 16 is formed part way. Refrigerant circulation hole 1
The inner wall surface of 6 is a (111) surface with a low etching rate. Then, the resist is peeled off. The reason why the coolant circulation hole 16 is formed halfway at this stage is that a slight etching amount is required when the coolant circulation hole 16 is completed in a later step.

(Iii) Next, as shown in FIG. 15C, on the thermal oxide film 6 on the substrate surface side, for example, by a sputtering method,
An aluminum film 120 having a thickness of 0.5 μm, for example, is formed as the first sacrificial layer. Then, photolithography and etching are performed thereon to process the aluminum film 120 into a pattern corresponding to the gap 32 shown in FIG. Depending on the thickness of the first sacrificial layer 120, the distance of the gap 32 shown in FIG. 1, that is, the distance A between the surface protection film 6 of the substrate 7 and the first insulating film 2 shown in FIG. 5 is determined. .

(Iv) Next, as shown in FIG. 16D, a silicon oxide film 2 having a thickness of 0.5 μm, for example, is formed thereon as the first insulating film 2 by, eg, sputtering.
Then, on the silicon oxide film 2, as a material of the heater layer 3, for example, a thickness of 0.01 μm is formed by, for example, a sputtering method.
A tantalum film having a thickness of m and a nickel film 140 having a thickness of 0.1 μm are formed. Subsequently, photolithography and etching are performed to perform the tantalum film and the nickel film 14
Pattern 0. Thus, the heater layer 3 having a U-shaped meandering pattern is formed on the first insulating film 2. The reason for forming the tantalum film is to increase the adhesion between the silicon oxide film 2 and the nickel film 140.

(V) Next, as shown in FIG. 16E, a silicon oxide film 4 having a thickness of 0.5 μm, for example, is formed thereon as a second insulating film by, eg, sputtering. Subsequently, as shown in FIG. 16F, photolithography and etching are performed to form an electrode extraction port 160 in the silicon oxide film 4.

(Vi) Next, as shown in FIG. 17G, as a part of the material (first metal layer) of the buckling body 1, for example, a thickness of 0.01 μm is formed thereon by, for example, a sputtering method. The tantalum film and the nickel film 170 having a thickness of 0.1 μm are formed. The reason for forming the tantalum film is to increase the adhesion between the silicon oxide film 4 and the nickel film 170.

(Vii) Next, as shown in FIG. 17 (h), a photoresist 180 is applied thereon, and a slit 40 (FIG. 4) to be formed in the silicon oxide films 2 and 4 is formed on the resist 180. An opening having a shape corresponding to the pattern of (see) is formed. Then, etching is performed to form slits 40 in the silicon oxide films 2 and 4.

(Viii) Next, as shown in FIG.
A photoresist 190 is applied on this, and photolithography is performed to remove the resist 190 from the slit 4
The shape corresponding to the 0 pattern is left. That is, the shape of the resist 190 is changed to the slit 4 of the silicon oxide films 2 and 4.
It is filled with 0 and has a shape protruding upward from the surface of the silicon oxide film 4 by a predetermined height (height exceeding the nickel plating film 200 described below) with the same pattern width as the slit 40.

(Ix) Next, as shown in FIG. 18 (j), the remaining portion of the material of the buckling body 1 having a predetermined thickness (for example, 5 μm) is formed on the silicon oxide film 4 by electrolytic plating. A nickel plating film 200 is formed. As the electrolytic plating method, for example, nickel plating using a nickel sulfamate bath with the nickel film 170 as an electrode can be adopted.

Incidentally, on the left side (X) of FIG. 18 (j),
Resist 190, 1 of nickel film 170, 200, etc.
The region sandwiched by 90 constitutes the buckling body 1, and the nickel film 1
Regions outside the resists 190, 190 of 70, 200, etc. form the wirings 51a, 51b shown in FIG.

(X) Next, as shown in FIG. 18 (k), an aluminum film 210 having a thickness of 0.5 μm, for example, is formed as a second sacrificial layer thereon by sputtering, for example.
Then, photolithography is performed and etching is performed using a potassium hydroxide solution as an etching solution to process the aluminum film 210 into a pattern corresponding to the gap 33 shown in FIG. Depending on the thickness of the second sacrificial layer 210, the distance of the gap 33 shown in FIG. 1, that is, FIG.
The distance D between the buckling body 1 and the diaphragm 5 shown therein is determined.

Since the etching of the second sacrificial layer 210 is performed using an alkaline etching solution (potassium hydroxide solution), the resist 190 existing outside the pattern of the second sacrificial layer 210 (see FIG. 18 (j)) is used. The left side (see X)) is removed together with the second sacrificial layer 210. On the other hand, the resist 190 existing in the pattern of the second sacrificial layer 210 remains under the second sacrificial layer 210 as it is, as shown in the right side (Y) of FIG.

(Xi) Next, as shown in FIG. 18L, as a part of the material (second metal layer) of the diaphragm 5, for example, a thickness of 0.01 μm is formed thereon by, for example, a sputtering method.
A tantalum film and a nickel film (not shown) having a thickness of 0.1 μm are formed. Then, a nickel-plated film 220 having a predetermined thickness (for example, 4 μm) is formed as the remaining portion of the material of the diaphragm 5 on this by using the above-mentioned nickel film as an electrode by an electrolytic plating method. As the electrolytic plating method, for example, nickel plating using a nickel sulfamate bath with the above nickel film as an electrode can be adopted. The reason for forming the tantalum film is to increase the adhesion between the nickel film 200 or the aluminum film 210 and the nickel film formed here.

(Xii) Next, as shown in FIG. 19 (m), the substrate 7 in this state is immersed in a potassium hydroxide solution to remove the nickel film 220 on the front surface side of the substrate and the thermal oxide film 6 on the rear surface side of the substrate. Using the as a mask, the silicon substrate 7 is etched. As a result, the coolant circulation hole 16 penetrating from the back surface side to the front surface side of the substrate 7 is completed. The inner peripheral surface of the coolant circulation hole 16 is a (111) surface with a low etching rate. The etching stops at the surface protective film 6 of the substrate 7.

(Xiii) Next, as shown in FIG.
The substrate 7 in this state is dipped in a hydrofluoric acid solution to form the thermal oxide film 6 on the rear surface side of the substrate and the aluminum film 12 as the first sacrificial layer.
0 and are removed by etching. Thereby, the gap 32 is formed between the surface protection film 6 of the substrate 7 and the first insulating film 2. Then, as shown in FIG. 19 (o), the substrate 7 is dipped in the potassium hydroxide solution to remove the resist 190 and the second
The aluminum film 210 as a sacrificial layer is etched and removed. As a result, a gap 33 is formed between the buckling body 1 and the diaphragm 5.

(Xiv) Next, as shown in FIG.
Photoresist 230 is applied to the surface of the substrate, photolithography and etching are performed, and the nickel film 2 is formed.
20 and the like are patterned to form the diaphragm 5.

(Xv) Next, as shown in FIG.
The photoresist 230 is peeled off. As a result, the pressure generating member 20 is completed.

(Xvi) Finally, as shown in FIG. 1, the nozzle plate 10 is attached to the front surface side of the substrate 7 in this state via the spacer 8 and the housing 9 is joined to the back surface side of the substrate 7. The inkjet head 90 is completed. The ink supply passage 14 is formed in the spacer 8, the nozzle orifice 11 is formed in the nozzle plate 10, and the coolant supply passage 35 is formed in the housing 9.

As described above, in this manufacturing method, since the pressure generating member 20 is manufactured by the semiconductor integrated process, the ink jet head 90 can be manufactured in a small size. In addition, the two gaps 32 in the pressure generating member 20,
Since 33 is continuously and collectively formed, the manufacturing process can be simplified. Moreover, since the gaps 32 and 33 are formed according to the thicknesses of the first sacrificial layer 120 and the second sacrificial layer 210, respectively, the distance between the gaps 32 and 33, that is, the surface of the substrate 7 shown in FIG. The distance A between the protective film 6 and the first insulating film 2 and the distance D between the buckling body 1 and the diaphragm 5 can be accurately set. For example, the interval A can be set to 0.1 μm or less and the interval D can be set to 1.0 μm or more. As a result, the response speed of the inkjet head 90 can be improved and high-speed printing can be realized.

[0132]

As is apparent from the above, in the ink jet head according to the first aspect, since the substrate exists on the back side of the pressure generating member, the thermal conductivity of the substrate is higher than that of the ink. By selecting one that is one digit or more larger, the heat of the pressure generating member, particularly the buckling member and the heater layer, can be rapidly released to the outside of the ink chamber through the substrate. Therefore, the cooling rate of the pressure generating member can be increased, and as a result, the response characteristics can be improved and high-speed printing can be performed. Further, since the buckling body and the heater layer that form the pressure generating member are separate layers, the shape of the heater layer can be formed in an elongated pattern regardless of the shape of the buckling body. In this case, reduce the amount of electricity to obtain the required amount of heat,
Power consumption can be reduced.

In the ink jet head according to the second aspect, as in the first aspect, since the substrate exists on the back side of the pressure generating member, the thermal conductivity of the substrate is one digit higher than that of the ink. By selecting the larger one, the heat of the pressure generating member, especially the buckling member, can be rapidly released to the outside of the ink chamber through the substrate. Therefore, the cooling rate of the pressure generating member can be increased,
As a result, the response characteristics can be improved and high-speed printing can be performed. Also, thanks to the diaphragm, it is possible to prevent the ink existing in the gap between the nozzle plate and the pressure generating member (diaphragm) from flowing around to the back side of the pressure generating member (diaphragm) during operation. Therefore, the ejection force and ejection speed of the ink can be increased. In addition, since the buckling body and the diaphragm forming the pressure generating member are separate bodies, the shape of the buckling body can be formed independently of the shape of the diaphragm. For example, the buckling body should be provided with a slit. You can In this case, as described later,
By circulating a refrigerant such as ink through the buckling member on the back side of the diaphragm, the buckling member can be cooled rapidly, and the response characteristics can be improved, and high-speed printing can be performed.

An ink jet head according to claim 3,
Similarly to claims 1 and 2, since the substrate exists on the back side of the pressure generating member, the pressure generation can be performed by selecting a material having a thermal conductivity higher than that of the ink by one digit or more. The heat of the member, particularly the buckling member and the heater layer, can be rapidly released to the outside of the ink chamber through the substrate. Therefore, the cooling rate of the pressure generating member can be increased, and as a result, the response characteristics can be improved and high-speed printing can be performed. Further, similarly to claim 1, since the buckling body and the heater layer forming the pressure generating member are separate layers, the shape of the heater layer is an elongated pattern regardless of the shape of the buckling body. Can be formed. In this case, it is possible to reduce the power consumption by reducing the energization amount for obtaining the required heat generation amount. Further, like the second aspect, the diaphragm prevents the ink existing in the gap between the nozzle plate and the pressure generating member (diaphragm) from flowing around to the back side of the pressure generating member (diaphragm) during operation. Therefore, the ejection force and ejection speed of the ink can be increased. In addition, since the buckling body and the diaphragm forming the pressure generating member are separate bodies, the shape of the buckling body can be formed independently of the shape of the diaphragm. For example, the buckling body should be provided with a slit. You can In this case, as described later,
By circulating a refrigerant such as ink through the buckling body on the back side of the diaphragm, the buckling body and the heater layer can be rapidly cooled, and the response characteristics can be improved and high-speed printing can be performed.

In the ink jet head of the fourth aspect, since the heater layer is provided along the back surface of both surfaces of the buckling member, the heater layer which has a particularly high temperature in the pressure generating member is used as the substrate. Can be cooled rapidly through. Therefore, the cooling rate of the pressure generating member can be further increased, and as a result, the response characteristics can be further improved and high-speed printing can be performed.

In the ink jet head of the fifth aspect, since the pressure generating member has the first insulating layer provided between the substrate and the heater layer, the space between the substrate and the heater layer is provided. Good insulation can be prevented, and current flowing through the heater layer can be prevented from leaking to the substrate. Therefore, it is possible to reduce the power consumption by reducing the amount of energization for obtaining the required amount of heat generation.

In the ink jet head of the sixth aspect, since the pressure generating member has the second insulating layer provided between the buckling body and the heater layer, the buckling body and the heater layer. Can be well insulated from each other and the current flowing through the heater layer can be prevented from leaking to the buckling body. Therefore, it is possible to reduce the power consumption by reducing the amount of energization for obtaining the required amount of heat generation.

In the ink jet head of the seventh aspect, since the diaphragm is formed in a substantially disc shape, the surface area of the diaphragm is small, but the ink chamber (gap between the nozzle plate and the pressure generating member) is small. The volume change amount can be increased. Therefore, although the surface area of the diaphragm is small, the ejection force and the ejection speed of the ink can be increased. Conversely, when the ink ejection force has a margin, the diameter of the diaphragm can be reduced to reduce the size of the inkjet head.

In the ink jet head of the eighth aspect, at least a part of the diaphragm other than the peripheral portion is connected to the buckling member. Therefore, after the heating period ends, the cooling period starts and the buckling member returns to its original position. When returning to the position (1), the diaphragm returns to its original position more quickly due to the restoring force of itself and the pulling force from the buckling body. Therefore, high-speed printing can be performed by improving the response characteristics of the pressure generating member.

In the ink jet head of the ninth aspect, since the central portion of the diaphragm is connected to the central portion of the buckling member, the portion (central portion) of the diaphragm that is displaced most during the heating period is the central portion. During the cooling period, the buckling body is pulled by the fastest returning portion (central portion). As a result, the diaphragm returns to its original position even faster. Therefore, high-speed printing can be performed by further improving the response characteristic of the pressure generating member.

In the ink jet head of claim 10,
Since a gap is provided between the buckling body and an intermediate portion between the peripheral portion of the diaphragm and a portion connected to the buckling body, the diaphragm is provided on the back side of the diaphragm. By circulating a coolant such as ink in the gap between the buckling member and the buckling member, the buckling member can be rapidly cooled. Therefore, the response characteristics can be further improved and high-speed printing can be performed.

According to the ink jet head of claim 11,
Since a gap is provided between the substrate and the portion of the pressure generating member that is located inside the peripheral portion of the buckling body, and between the buckling body and the substrate on the back side of the diaphragm. The buckling body and the heater layer can be rapidly cooled by circulating a coolant such as ink in the gap. Therefore, the response characteristics can be further improved and high-speed printing can be performed.

According to the ink jet head of claim 12,
Since the distance between the substrate and the portion of the pressure generating member is set within the range of 0.05 μm to 2.0 μm, the gap between the substrate and the pressure generating member can be easily formed. Therefore, the response characteristics of the pressure generating member can be favorably maintained. That is, the distance of the gap is 0.
If the thickness is 05 μm or more, a sacrifice layer (processing layer) on the substrate
The gap can be formed by sequentially laminating the material of the pressure generating member and the sacrificial layer with an etching solution. In addition, the distance of the gap is 2.0
When the thickness is not more than μm, the heat of the pressure generating member, particularly the buckling member and the heater layer, can be rapidly released to the outside of the ink chamber through the substrate during the cooling period.

According to the ink jet head of the thirteenth aspect,
In the portion of the pressure generating member that is present inside the peripheral portion of the buckling body, since a slit that penetrates from the surface facing the substrate to the surface of the buckling body on the diaphragm side is provided, On the back side of the diaphragm, the buckling body can be rapidly cooled by circulating a coolant such as ink through the slit. In particular, when there are gaps between the diaphragm and the buckling member or between the substrate and the pressure generating member, these gaps communicate with each other through the slits, so that the cooling effect can be further enhanced. Therefore, the response characteristics can be further improved and high-speed printing can be performed.

In the ink jet head of claim 14,
Since a plurality of slits are provided and the strip-shaped portion of the buckling body sandwiched by the slits is designed to buckle, for example, by attaching the peripheral portion of the buckling body to the substrate over the entire circumference. The thermal stress of the buckling portion due to repeated heating and cooling can be received in the entire peripheral portion. Therefore, the thermal stress of the buckling portion can be prevented from being applied only to a specific portion, and the thermal stress can be relaxed and received by the entire peripheral portion. Therefore, it is possible to prevent the attachment position of the substrate and the buckling member from being damaged, and it is possible to extend the life of the inkjet head.

According to the ink jet head of claim 15,
Since the substrate is provided with a refrigerant circulation hole that penetrates the substrate and faces a portion of the pressure generating member located inside the peripheral portion of the buckling body, the refrigerant circulation hole is formed. Through, the coolant such as ink can be supplied from the back side of the substrate to the front side of the substrate. The supplied coolant flows between the front side and the back side of the substrate as the pressure generating member is displaced and returned by heating and cooling. Therefore, the pressure generating member can be cooled rapidly. This is especially significant when the diaphragm is provided and ink does not wrap around to the back side of the diaphragm. Further, when there is a gap between the diaphragm and the buckling member, or between the substrate and the pressure generating member, further in the portion of the pressure generating member inside the peripheral portion of the buckling member, In the case where a slit penetrating from the surface facing the substrate to the surface of the buckling body on the diaphragm side is provided,
Since the refrigerant flows through these gaps and slits,
Further, the cooling effect can be increased. Therefore, the response characteristics can be further improved and high-speed printing can be performed.

In the ink jet head of claim 16,
Since the hole for refrigerant circulation is gradually reduced in size from the back side of the substrate toward the front side, as compared with the case where the hole for refrigerant circulation is not present, the facing area between the pressure generating member and the substrate surface is It does not decrease much. Therefore, the heat of the pressure generating member, especially the buckling member and the heater layer, can be rapidly released to the outside of the ink chamber through the substrate. Therefore, the cooling rate of the pressure generating member can be kept high,
Good response characteristics can be maintained.

According to the ink jet head of claim 17,
Since a coolant reservoir communicating with the coolant circulation hole is formed on the back side of the substrate, a coolant such as ink can be supplied from the coolant reservoir to the front side of the substrate through the coolant circulation hole.

According to the ink jet head manufacturing method of the eighteenth aspect, since the pressure generating member can be manufactured by the semiconductor integrated process, the ink jet head can be manufactured in a small size. Further, the first sacrificial layer and the second sacrificial layer are continuously etched to form two gaps, a gap between the substrate and the pressure generating member and a gap between the buckling body and the diaphragm in the pressure generating member. Then, it can be collectively formed. Therefore, the manufacturing process can be simplified. Moreover, since the two gaps are formed in accordance with the thicknesses of the first sacrificial layer and the second sacrificial layer, the distance between the gaps can be set with high accuracy.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing the overall configuration of an inkjet head of the present invention.

FIG. 2 is a diagram illustrating the operation of the inkjet head.

FIG. 3 is a perspective view showing the inkjet head in an exploded state.

FIG. 4 is a perspective view showing in detail the buckling body and the heater layer and the like on the back side thereof in FIG.

FIG. 5 is a diagram showing a main part of the inkjet head.

FIG. 6 is a diagram schematically showing a configuration of an apparatus used for heat dissipation simulation.

FIG. 7 is a drive waveform for driving the buckling body under the driving condition 1, the displacement amount ΔZ and the rising temperature Δ of the central portion of the buckling body.
It is a figure which shows the time passage of T.

FIG. 8 is a diagram showing the dependence of the response speed on the distance A between the surface protection film of the substrate and the first insulating film and the dependence of the response speed on the thickness B of the first insulating film.

FIG. 9 is a diagram showing the dependence of the response speed on the thickness C of the second insulating film and the dependence of the response speed on the distance D of the gap between the buckling body and the diaphragm.

FIG. 10 is a plan view schematically showing the configuration of a model used for a fluid analysis simulation.

FIG. 11 is a schematic cross-sectional view taken along line X ₂ -X ₂ of FIG.

FIG. 12 is a diagram showing the dependence of the ink ejection speed on the length F, width G, and depth H of the ink supply path.

FIG. 13 is a diagram showing a drive waveform for driving a buckling body under a driving condition 2 and a time course of a displacement amount ΔZ and a rising temperature ΔT of a central portion of the buckling body.

FIG. 14 is a diagram showing the dependence of the discharge speed V on the power consumption W per unit volume of the buckling body.

FIG. 15 is a process chart for explaining the manufacturing method of the inkjet head according to the embodiment of the present invention.

FIG. 16 is a process chart for explaining the manufacturing method of the inkjet head according to the embodiment of the present invention.

FIG. 17 is a process chart for explaining the manufacturing method of the inkjet head according to the embodiment of the present invention.

FIG. 18 is a process chart for explaining the manufacturing method of the inkjet head according to the embodiment of the present invention.

FIG. 19 is a process drawing for explaining the manufacturing method of the inkjet head according to the embodiment of the present invention.

FIG. 20 is a process drawing for explaining the manufacturing method of the inkjet head according to the embodiment of the present invention.

FIG. 21 is a cross-sectional view showing the configuration of a conventional inkjet head.

[Explanation of symbols]

1 Buckling Body 2 First Insulating Film 3 Heater Layer 4 Second Insulating Film 5 Diaphragm 6 Surface Protective Film 7 Substrate 8 Spacer 9 Housing 10 Nozzle Plate 11 Nozzle Orifice 13a, 13
b Electrode Pad 14 Ink Supply Channel 15 Ink 16 Refrigerant Circulation Hole 31 Ink Chamber 32, 33 Gap 34 Refrigerant Reservoir 90 Inkjet Head 120 First Sacrificial Layer 210 Second
Sacrificial layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yorisei Ishii 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Co., Ltd. Co., Ltd. (72) Inventor Shoji Kimura 22-22 Nagaike-cho, Nagano-cho, Abeno-ku, Osaka, Osaka (72) Yutaka Onda, 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Prefecture

Claims (18)

[Claims] 1. An ink chamber including a nozzle plate having a nozzle opening and a substrate facing the nozzle plate in a part of a peripheral wall, and a pressure generating member provided in the ink chamber and facing the nozzle plate. An ink jet head for generating a pressure in the ink chamber by the deformation of the pressure generating member to eject the ink liquid in the ink chamber to the outside through the nozzle opening, wherein the pressure generating member has a substantially plate shape and a peripheral edge. A buckling body, in which both end portions of at least one direction are attached to the substrate, the buckling body can be in a non-displacement state in which there is substantially no thermal stress, and a buckling state in which the buckling state is caused by thermal expansion; An ink jet head comprising: a heater layer which is provided along one surface of a buckling member and which generates heat when energized. 2. An ink chamber including a nozzle plate having a nozzle opening and a substrate facing the nozzle plate in a part of a peripheral wall, and a pressure generating member provided in the ink chamber and facing the nozzle plate. An ink jet head for generating a pressure in the ink chamber by the deformation of the pressure generating member to eject the ink liquid in the ink chamber to the outside through the nozzle opening, wherein the pressure generating member has a substantially plate shape and a peripheral edge. A buckling member, which is attached to the substrate at least at both ends in at least one direction, and which can take a non-displacement state in which there is substantially no thermal stress and a buckling state in which it buckles due to thermal expansion; It is made of a plate-like flexible material, and is attached to the peripheral edge portion of the buckling body along the surface on the nozzle plate side of both surfaces of the buckling body and the peripheral edge portion. An ink jet head, comprising: a diaphragm provided in a state. 3. An ink chamber including a nozzle plate having a nozzle opening and a substrate facing the nozzle plate in a part of a peripheral wall, and a pressure generating member provided in the ink chamber and facing the nozzle plate. An ink jet head for generating a pressure in the ink chamber by the deformation of the pressure generating member to eject the ink liquid in the ink chamber to the outside through the nozzle opening, wherein the pressure generating member has a substantially plate shape and a peripheral edge. A buckling body, in which both end portions of at least one direction are attached to the substrate, the buckling body can be in a non-displacement state in which there is substantially no thermal stress, and a buckling state in which the buckling state is caused by thermal expansion; A heater layer that is provided along one surface of the buckling body and that generates heat when energized, and is made of a substantially plate-shaped flexible material. Along the surface of the rate-side, and an ink jet head peripheral portion is characterized in that a diaphragm is provided in a state of being attached to the periphery of the buckling member. 4. The ink jet head according to claim 1 or 3, wherein the heater layer is provided along the surface of the buckling body on the side of the substrate. head. 5. The ink jet head according to claim 1, wherein the pressure generating member has a first insulating layer provided between the substrate and the heater layer. An inkjet head characterized in that. 6. The ink jet head according to claim 1, wherein the pressure generating member is provided between the buckling body and the heater layer. An inkjet head having an insulating layer. 7. The inkjet head according to claim 2 or 3, wherein the diaphragm is formed in a substantially disc shape. 8. The inkjet head according to claim 2, wherein, in addition to the peripheral portion of the diaphragm, at least a part other than the peripheral portion of the diaphragm is connected to the buckling body. Inkjet head characterized by being provided. 9. The inkjet head according to claim 2, wherein a central portion of the diaphragm is connected to a central portion of the buckling body. Inkjet head. 10. The ink jet head according to any one of claims 2, 3, 7, 8 and 9, wherein between the peripheral portion of the diaphragm and a portion connected to the buckling body. An ink-jet head, characterized in that a gap is provided between the intermediate portion of and the buckling member. 11. The inkjet head according to claim 1, wherein between the portion of the pressure generating member located inside the peripheral portion of the buckling member and the substrate. An ink jet head having a gap. 12. The ink jet head according to claim 11, wherein a distance between the substrate and the portion of the pressure generating member is set within a range of 0.05 μm to 2.0 μm. Inkjet head to do. 13. The inkjet head according to any one of claims 1 to 12, wherein a portion of the pressure generating member that is located inside the peripheral portion of the buckling member faces the substrate. To the surface of the buckling body on the side of the nozzle plate. 14. The inkjet head according to claim 13, wherein a plurality of the slits are provided, and a belt-shaped portion of the buckling body sandwiched by the slits is buckled. Inkjet head. 15. The inkjet head according to any one of claims 1 to 14, wherein the substrate penetrates the substrate and is located inside the peripheral portion of the buckling member in the pressure generating member. An ink jet head characterized in that a hole for circulating a refrigerant is provided facing a portion existing in the. 16. The ink jet head according to claim 15, wherein the coolant circulation hole has a size gradually decreasing from a side of the substrate opposite to the pressure generating member toward the pressure generating member. An inkjet head characterized in that. 17. The ink jet head according to claim 15 or 16, wherein a coolant reservoir communicating with the coolant circulation hole is formed on a side of the substrate opposite to the pressure generating member. head. 18. An ink chamber including a nozzle plate having a nozzle opening and a substrate facing the nozzle plate in a part of a peripheral wall thereof, and a pressure generating member provided in the ink chamber and facing the nozzle plate, The pressure generating member is an inkjet head having a plate-shaped buckling body, a heater layer provided on the substrate side of the buckling body, and a diaphragm provided on the nozzle plate side of the buckling body. And a step of forming a first sacrificial layer having a pattern occupying a predetermined closed region on a surface of a substrate, the first sacrificial layer being covered so as to cover the first sacrificial layer. Forming a first insulating layer of a sacrificial layer and a material that can be selectively etched; and forming a heater on the first insulating layer having a pattern passing through a region occupied by the first sacrificial layer. A step of forming a heat insulating layer, a step of forming a second insulating layer made of a material that can be selectively etched with the first sacrificial layer so as to cover each of the layers, and along both sides of the pattern of the heater layer. A step of forming a slit from the surface of the second insulating layer to the surface of the first sacrificial layer, and applying resist on the substrate and performing photolithography to fill the inside of the slit and A step of forming a resist wall protruding from the surface side of the second insulating layer by a predetermined height while keeping the width, and a first step for forming a buckling body on the second insulating layer by plating. Forming a metal layer with a predetermined thickness that does not exceed the height of the resist wall; and forming a predetermined portion of the surface of the first metal layer and the slit in a closed region substantially corresponding to the first sacrificial layer. To cover
A step of forming a second sacrificial layer made of a material that can be selectively etched with the first metal layer, and the second sacrificial layer for configuring a diaphragm so as to cover the layers on the surface of the substrate. And a step of forming a metal layer made of a material that can be selectively etched on the entire surface, and etching is performed from the back surface side of the substrate to form a hole reaching the first sacrificial layer on the front surface side of the substrate. The first sacrificial layer is selectively etched and removed with respect to the first and second insulating layers through a hole, the resist wall is subsequently removed, and further, the resist wall is removed and a slit is formed. A step of selectively etching and removing the second sacrificial layer with respect to both the first and second metal layers; and a step of patterning the second metal layer to form a diaphragm having a predetermined shape. A method of manufacturing an ink jet head characterized in that it comprises.