JPH11151815A - Ink-jet type recording head and ink-jet type recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet type recording head which can prevent the peeling and cracking of the end parts of a piezoelectric body active part. SOLUTION: In an ink-jet type recording head having a thin wall part 350 which is thinner than a part corresponding to a piezoelectric body active part 320 in a part along the fringe part of a pressure generation chamber 12 at least on both sides in the width direction of the active part 320, A vibration regulation part 360 for regulating the movement of vibration plates 50, 60 is installed close to the end part of the active part 320 or at least parts on both sides in the width direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a part of a pressure generating chamber which communicates with a nozzle opening for discharging ink droplets, which is constituted by a vibrating plate, and a piezoelectric element is formed on the surface of the vibrating plate. The present invention relates to an ink jet recording head and an ink jet recording apparatus that eject ink droplets by displacement.

[0002]

2. Description of the Related Art A part of a pressure generating chamber communicating with a nozzle opening for discharging ink droplets is constituted by a vibrating plate, and the vibrating plate is deformed by a piezoelectric element to pressurize the ink in the pressure generating chamber to pass through the nozzle opening. Two types of ink jet recording heads that eject ink droplets have been commercialized, one using a longitudinal vibration mode piezoelectric actuator that expands and contracts in the axial direction of the piezoelectric element, and the other using a flexural vibration mode piezoelectric actuator. ing.

In the former method, the volume of the pressure generating chamber can be changed by bringing the end face of the piezoelectric element into contact with the diaphragm, so that a head suitable for high-density printing can be manufactured. There is a problem in that a difficult process of cutting into a comb shape in accordance with the arrangement pitch of the openings and an operation of positioning and fixing the cut piezoelectric element in the pressure generating chamber are required, and the manufacturing process is complicated.

On the other hand, in the latter, a piezoelectric element can be formed on a diaphragm by a relatively simple process of sticking a green sheet of a piezoelectric material according to the shape of a pressure generating chamber and firing the green sheet. In addition, there is a problem that a certain area is required due to the use of flexural vibration, and that high-density arrangement is difficult.

On the other hand, in order to solve the latter disadvantage of the recording head, a uniform piezoelectric material layer is formed by a film forming technique over the entire surface of the diaphragm as disclosed in Japanese Patent Application Laid-Open No. 5-286131. It has been proposed that the piezoelectric material layer is cut into a shape corresponding to the pressure generating chamber by a lithography method and a piezoelectric element is formed so as to be independent for each pressure generating chamber.

[0006] According to this, the operation of attaching the piezoelectric element to the diaphragm becomes unnecessary, and not only can the piezoelectric element be manufactured by a precise and simple method such as lithography, but also the thickness of the piezoelectric element can be reduced. There is an advantage that it can be made thin and can be driven at high speed. In this case, the piezoelectric actuator corresponding to each pressure generating chamber can be driven by providing at least only the upper electrode for each pressure generating chamber while the piezoelectric material layer is provided on the entire surface of the vibration plate.

In a recording head using such a flexure mode piezoelectric actuator, the piezoelectric elements corresponding to the respective pressure generating chambers are generally covered with an insulator layer, and the insulator layers drive the respective piezoelectric elements. Windows (hereinafter, referred to as contact holes) are provided corresponding to the respective pressure generating chambers so as to form a connection portion with a lead electrode for supplying a voltage for the piezoelectric element, and a connection portion between each piezoelectric element and the lead electrode is formed. It is formed in the contact hole.

[0008]

By the way, in the above-mentioned ink jet recording head, in order to improve the displacement efficiency of the diaphragm by driving the piezoelectric actuator, the diaphragm corresponding to both sides of the piezoelectric element is provided. A thinning structure has been proposed. However, when the displacement is increased as described above, there is a problem that the piezoelectric element is cracked or peeled off, particularly in the vicinity of both ends in the longitudinal direction of the pressure generating chamber.

[0009] These problems become particularly problematic when the piezoelectric material layer is formed by a film forming technique. That is, since the piezoelectric material layer formed by the film formation technique is very thin, the rigidity thereof is lower than that of the piezoelectric material layer attached.

In view of such circumstances, an object of the present invention is to provide an ink jet recording head and an ink jet recording apparatus which can prevent peeling and cracking of an end of a piezoelectric active portion.

[0011]

According to a first aspect of the present invention, there is provided a vibration plate constituting a part of a pressure generating chamber communicating with a nozzle opening, and a piezoelectric member formed on the vibration plate. A piezoelectric active portion of the piezoelectric element in a region opposed to the pressure generating chamber, wherein the vibration plate extends along the edge of the pressure generating chamber at least on both sides in the width direction of the piezoelectric active portion. In the ink jet type recording head having a thin portion thinner than the thickness of the portion corresponding to the piezoelectric active portion, at least a portion near the end of the piezoelectric active portion or on both sides in the width direction, An ink jet recording head is provided with a vibration restricting portion for restricting movement.

In the first aspect, since the vibration restricting portion is provided in a part of the piezoelectric active portion, the vibration of the piezoelectric element is partially restricted, and cracking and peeling are prevented.

According to a second aspect of the present invention, in the first aspect, the vibration restricting portion is provided on a longitudinally outer side and on both sides of an end of the piezoelectric active portion. In the head.

[0014] In the second aspect, the vibration of the end of the piezoelectric active portion is regulated, and cracking and peeling at the end are prevented.

According to a third aspect of the present invention, in the first aspect, the vibration restricting portion is provided outside a longitudinal end of an end of the piezoelectric active portion, and the vibration plates on both sides of the vibration restricting portion are provided. Is an ink jet recording head characterized in that it is the thin portion.

In the third aspect, the vibration of the end portion of the piezoelectric active portion is restricted, and cracking and peeling at the end portion are prevented.

According to a fourth aspect of the present invention, in the ink jet recording head according to the first aspect, the vibration restricting portion is provided on a portion on both sides in the width direction of the piezoelectric active portion. It is in.

In the fourth aspect, the vibration is restricted at a part of the central portion of the piezoelectric body active portion, and the crack and peeling at the end portion are prevented.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the vibration restricting portion is a thick portion in which the thickness of the diaphragm is larger than the thin portion. Ink-jet recording head.

In the fifth aspect, the vibration of the piezoelectric element is partially restricted by providing the partial thick portion.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the vibration restricting portion has another layer for restricting vibration of the vibration restricting portion. In the recording head.

In the sixth aspect, the vibration of the piezoelectric element is partially regulated by providing another layer partially.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the vibration restricting portion includes an inactive portion having an inactive piezoelectric layer on the diaphragm. The feature is the ink jet recording head.

In the seventh aspect, the vibration of the piezoelectric element is partially regulated by providing the partially inactive piezoelectric layer.

According to an eighth aspect of the present invention, in the seventh aspect, the inactive portion is formed on a portion of the piezoelectric layer from which the upper electrode is removed or on the piezoelectric layer via an insulating layer. An ink jet recording head is characterized in that it is a portion provided with electrodes.

In the eighth aspect, the vibration of the piezoelectric element is partially restricted by removing the upper electrode or providing the upper electrode via an insulating layer.

According to a ninth aspect of the present invention, in any one of the first to eighth aspects, the piezoelectric active portion is provided apart from a peripheral wall of the pressure generating chamber, and is provided on an upper surface of the piezoelectric active portion. An ink jet recording head has a contact portion for connecting a lead electrode and an upper electrode.

In the ninth aspect, application of a voltage to the piezoelectric active section is performed via the contact section.

According to a tenth aspect of the present invention, in any one of the first to ninth aspects, an insulator layer is formed on an upper surface of the piezoelectric active portion, and a contact for connecting a lead electrode and an upper electrode is provided. The part is formed in a contact hole formed in the insulating part.

In the tenth aspect, the application of the voltage to the piezoelectric active portion is performed through the contact portion formed through the insulator layer.

According to an eleventh aspect of the present invention, in any one of the first to eighth aspects, the piezoelectric layer and the upper electrode constituting the piezoelectric active part are arranged such that the upper electrode extends from the longitudinal end of the piezoelectric active part. An ink jet recording head is provided continuously up to a region facing the peripheral wall of the pressure generating chamber.

In the eleventh aspect, the vibration of the vibration plate is regulated more by the portion where the piezoelectric layer and the upper electrode cross the boundary with the peripheral wall of the pressure generating chamber than by other portions.

According to a twelfth aspect of the present invention, in the eleventh aspect, the vibration restricting portion is provided continuously up to a region where the piezoelectric layer and the upper electrode face the peripheral wall of the pressure generating chamber. The ink jet recording head is provided in a portion.

In the twelfth aspect, the vibration of the diaphragm can be effectively restricted at the portion where the piezoelectric layer and the upper electrode cross the boundary with the peripheral wall of the pressure generating chamber.

According to a thirteenth aspect of the present invention, in any one of the first to twelfth aspects, the pressure generating chamber is formed on a silicon single crystal substrate by anisotropic etching, and each layer of the piezoelectric element is formed by film formation. An ink jet recording head is formed by a lithography method.

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

According to a fourteenth aspect of the present invention, there is provided an ink jet recording apparatus comprising the ink jet recording head according to any one of the first to thirteenth aspects.

According to the fourteenth aspect, it is possible to realize an ink jet recording apparatus in which the durability of the head is improved and the reliability is improved.

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments.

(Embodiment 1) FIG. 1 is an exploded perspective view showing an ink jet recording head according to Embodiment 1 of the present invention, and FIG. 2 is a plan view thereof and a longitudinal section of one pressure generating chamber. It is a figure showing a structure.

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

One surface of the flow path forming substrate 10 is an opening surface, and the other surface is formed with an elastic film 50 having a thickness of 1 to 2 μm and made of silicon dioxide previously formed by thermal oxidation.

On the other hand, the silicon single crystal substrate is anisotropically etched on the opening surface of the flow path forming substrate
A nozzle opening 11 and a pressure generating chamber 12 are formed.

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

In this embodiment, the long side of each pressure generating chamber 12 is formed by the first (111) plane, and the short side is formed by the second (111) plane. The pressure generating chamber 12 is provided on the flow path forming substrate 1.
It is formed by etching until it reaches the elastic film 50 almost through 0. The amount of the elastic film 50 that is attacked by the alkaline solution for etching the silicon single crystal substrate is extremely small.

On the other hand, each nozzle opening 11 communicating with one end of each pressure generating chamber 12 is formed narrower and shallower than the pressure generating chamber 12. That is, the nozzle opening 11 is formed by partially etching (half-etching) the silicon single crystal substrate in the thickness direction. In addition,
Half etching is performed by adjusting the etching time.

Here, the size of the pressure generating chamber 12 for applying the ink droplet ejection pressure to the ink and the size of the nozzle opening 11 for ejecting the ink droplet depend on the amount of the ejected ink droplet, the ejection speed, and the ejection frequency. Optimized. For example,
When recording 360 ink droplets per inch, the nozzle openings 11 need to be formed with a groove width of several tens of μm with high accuracy.

Further, each pressure generating chamber 12 and a common ink chamber 31 described later are connected to each pressure generating chamber 1 of the sealing plate 20 described later.
The ink is supplied from a common ink chamber 31 through the ink supply communication port 21 formed at a position corresponding to one end of the pressure generation chamber 12. Distributed to

The sealing plate 20 is provided with an ink supply communication port 21 corresponding to each of the pressure generating chambers 12 and has a thickness of, for example, 0.1 to 1 mm and a linear expansion coefficient of 300 ° C. or less. , For example, 2.5-4.5 [× 10 ⁻⁶ / ° C.]. In addition, the ink supply communication port 21
Each of the pressure generating chambers 1 is, as shown in FIGS.
It may be one slit hole 21A crossing the vicinity of the second ink supply side end or a plurality of slit holes 21B. The sealing plate 20 entirely covers one surface of the flow path forming substrate 10 on one surface, and also serves as a reinforcing plate for protecting the silicon single crystal substrate from impact and external force. In addition, the sealing plate 20
The other surface constitutes one wall surface of the common ink chamber 31.

The common ink chamber forming substrate 30 forms the peripheral wall of the common ink chamber 31, and is formed by punching a stainless steel plate having an appropriate thickness according to the number of nozzles and the ink droplet ejection frequency. . In the present embodiment, the thickness of the common ink chamber forming substrate 30 is 0.2 mm.

The ink chamber side plate 40 is made of a stainless steel substrate, and one surface of the ink chamber side plate 40 constitutes one wall of the common ink chamber 31. In the ink chamber side plate 40, a thin wall 41 is formed by forming a concave portion 40a by half etching on a part of the other surface, and an ink introduction port 42 for receiving ink supply from the outside is punched and formed. ing. The thin wall 41 is for absorbing pressure generated at the time of ink droplet ejection toward the side opposite to the nozzle opening 11, and is unnecessary for the other pressure generating chambers 12 via the common ink chamber 31. Prevents positive or negative pressure from being applied.
In the present embodiment, the ink chamber side plate 40 is made 0.2 mm in consideration of rigidity required at the time of connection between the ink introduction port 42 and an external ink supply means, and a part of the thickness is 0.02 mm.
The thickness of the ink chamber side plate 40 may be 0.02 mm from the beginning in order to omit the formation of the thin wall 41 by half etching.

On the other hand, a thickness of, for example, about 0.5 μm
A lower electrode film 60, a piezoelectric film 70 having a thickness of, for example, about 1 μm, and an upper electrode film 80 having a thickness of, for example, about 0.1 μm are formed by lamination in a process to be described later.
0. Here, the piezoelectric element 300 refers to a portion including the lower electrode film 60, the piezoelectric film 70, and the upper electrode film 80. Generally, one of the electrodes of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric film 70 are patterned for each pressure generating chamber 12. Here, a portion which is constituted by one of the patterned electrodes and the piezoelectric film 70 and in which a piezoelectric strain is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion 320. In the present embodiment, the lower electrode film 60 is used as a common electrode of the piezoelectric element 300 and the upper electrode film 80 is used as an individual electrode of the piezoelectric element 300. In any case, the piezoelectric active portion is formed for each pressure generating chamber. Also, here
The piezoelectric element 300 and a diaphragm whose displacement is generated by driving the piezoelectric element 300 are referred to as a piezoelectric actuator. In the example described above, the elastic film 50 and the lower electrode film 6
Although 0 functions as a diaphragm, the lower electrode film may also serve as an elastic film.

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

As shown in FIG. 4A, first, a silicon single crystal substrate wafer serving as the flow path forming substrate 10 is
Thermal oxidation is performed in a diffusion furnace at 0 ° C. to form an elastic film 50 made of silicon dioxide.

Next, as shown in FIG. 4B, a lower electrode film 60 is formed by sputtering. Pt or the like is preferable as the material of the lower electrode film 60. This is because a piezoelectric film 70 described later, which is formed by a sputtering method or a sol-gel method,
After film formation, 600 to 10 in an air atmosphere or an oxygen atmosphere
This is because it is necessary to perform crystallization by firing at a temperature of about 00 ° C. That is, the material of the lower electrode film 60 must be able to maintain conductivity at such a high temperature and in an oxidizing atmosphere. In particular, when PZT is used for the piezoelectric film 70, the conductivity of the material by diffusion of PbO is increased. It is desirable that there is little change in sex, and Pt is preferred for these reasons.

Next, as shown in FIG. 4C, a piezoelectric film 70 is formed. The piezoelectric film 70 can be formed by a sputtering method, but in the present embodiment, a so-called sol in which a metal organic substance is dissolved and dispersed in a solvent is applied, dried, gelled, and further baked at a high temperature. A so-called sol-gel method for obtaining a piezoelectric film 70 made of a metal oxide is used. As a material for the piezoelectric film 70, a lead zirconate titanate (PZT) -based material is suitable when used in an ink jet recording head.

Next, as shown in FIG. 4D, an upper electrode film 80 is formed. The upper electrode film 80 only needs to be a material having high conductivity, and many metals such as Al, Au, Ni, and Pt, and a conductive oxide can be used. In the present embodiment, P
t is formed by sputtering.

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

First, as shown in FIG. 5A, the lower electrode film 60, the piezoelectric film 70 and the upper electrode film 80 are etched together to pattern the entire pattern of the lower electrode film 60. Next, as shown in FIG. 5B, only the piezoelectric film 70 and the upper electrode film 80 are etched to form the piezoelectric active portion 32.
0 patterning is performed. Next, as shown in FIG. 5 (c), the piezoelectric active region is a region opposed to both sides in the width direction of each pressure generating chamber 12 (in FIG. 5, the pressure generating chamber 12 has not been formed yet but is indicated by a broken line). By removing portions of the lower electrode film 60 corresponding to the arms of the diaphragm on both sides of the portion 320, a lower electrode film removing portion 350 is formed. Thus, the lower electrode film removing section 3
By providing 50, the amount of displacement due to application of a voltage to the piezoelectric body active section 320 is improved.

As described above, first, the lower electrode film 60
Is formed, and then the piezoelectric active portion 32 is formed.
The patterning is completed by patterning 0 and finally patterning the lower electrode film removing section 350.

The thus formed piezoelectric active part 320
FIG. 6 shows a planar positional relationship with the lower electrode film removing unit 350.

As shown in FIG. 6A, the piezoelectric active portion 320 including the piezoelectric film 70 and the upper electrode film 80 is provided in a region facing the pressure generating chamber 12, and the lower electrode film removing portion 350 is provided. Are provided adjacent to both sides of the piezoelectric active portion 320 in the width direction. The portion where the lower electrode film removing portion 350 is provided is a portion called a so-called arm portion of the diaphragm, and a portion facing the vicinity of an edge along the both sides in the width direction of the pressure generating chamber 12. 6B, the lower electrode films 60 on both sides of the piezoelectric active portion 320 are removed. In the present embodiment, the lower electrode film removing unit 3
Reference numeral 50 is formed excluding portions adjacent to both ends of the piezoelectric active portion 320. Therefore, in a region opposed to both ends in the longitudinal direction of the pressure generating chamber 12, CC ′ in FIG.
As shown in the cross-sectional view, the lower electrode film 60 exists on both sides in the width direction and the outer side in the longitudinal direction of both ends of the piezoelectric active portion 320, and the thickness thereof becomes a relatively thick thick film portion 360, It is a vibration restricting unit that partially restricts the vibration of the diaphragm.

With such a structure, the vibration of the vibration plate due to the voltage application is restricted only in the vicinity of both ends of the piezoelectric active portion 320, and the displacement becomes relatively small. Since the amount of displacement at the end can be suppressed without significantly lowering it, peeling and cracking of the end of the piezoelectric active portion 320 can be prevented. The thick film portion 360 may be provided at one end of the pressure generating chamber 12.

In this embodiment, the lower electrode film removing section 3
Although the lower electrode film 50 is formed by completely removing the lower electrode film 60, as shown in FIG. 6D, the lower electrode film 60 is partially thinned by removing a part of the lower electrode film 60 by half etching or the like. The removing unit 350A may be used. In this case, the lower electrode film 60 may serve as an elastic body and a lower electrode without the elastic film 50.

As described above, after patterning the lower electrode film 60 and the like, preferably, at least the periphery of the upper surface of each upper electrode film 80, and the side surfaces of the piezoelectric film 70 and the lower electrode film 60 are electrically insulated. An insulating layer 90 having a property is formed (see FIG. 1). The insulator layer 90 is formed of a material that can be formed by a film formation method or shaped by etching, for example, silicon oxide, silicon nitride, or an organic material, preferably photosensitive polyimide having low rigidity and excellent electrical insulation. Is preferred.

Then, each piezoelectric active portion 3 of the insulator layer 90
A contact hole 90a that exposes a part of the upper electrode film 80 for connecting to a lead electrode 100 described later is formed in a part of the part that covers the upper surface of the part corresponding to one end of 20. One end is connected to each upper electrode film 80 via the contact hole 90a, and the other end is formed with a lead electrode 100 extending to the connection terminal portion. The lead electrode 100 is formed so as to be as narrow as possible so as to reliably supply a drive signal to the upper electrode film 80.

FIG. 7 shows a process of forming such an insulator layer.
Shown in

First, as shown in FIG. 7A, an insulator layer 90 is formed so as to cover the periphery of the upper electrode film 80 and the side surfaces of the piezoelectric film 70 and the lower electrode film 60. This insulator layer 9
The preferred material of 0 is as described above, but in this embodiment, a negative photosensitive polyimide is used.

Next, as shown in FIG. 7B, by patterning the insulator layer 90, each of the pressure generating chambers 12 is formed.
A contact hole 90a is formed in a portion corresponding to the vicinity of the end on the ink supply side. The contact hole 90
a may be provided at a portion of the pressure generating chamber 12 corresponding to the piezoelectric active portion 320, and may be provided at, for example, a central portion or a nozzle-side end portion.

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

The above is the film forming process. After forming the film in this manner, as shown in FIG. 7C, the silicon single crystal substrate is subjected to anisotropic etching with the above-described alkali solution to form the pressure generating chamber 12 and the like. In addition,
In the series of film formation and anisotropic etching described above, a number of chips are simultaneously formed on one wafer, and after completion of the process, each of the flow path forming substrates 10 having one chip size as shown in FIG. To divide. Further, the divided flow path forming substrate 10 is sequentially adhered and integrated with the sealing plate 20, the common ink chamber forming substrate 30, and the ink chamber side plate 40 to form an ink jet recording head.

The ink-jet head thus configured takes in ink from an ink inlet 42 connected to an external ink supply means (not shown), fills the interior from the common ink chamber 31 to the nozzle opening 11 with ink, and
In accordance with a recording signal from an external drive circuit (not shown), a voltage is applied between the lower electrode film 60 and the upper electrode film 80 via the lead electrode 100, and the elastic film 50, the lower electrode film 60, and the piezoelectric film 70 The pressure generating chamber 1 is deformed by bending.
The pressure in 2 increases, and ink droplets are ejected from nozzle opening 11.

(Embodiment 2) FIG. 8 shows the shapes of a piezoelectric active portion and a pressure generating chamber of an ink jet recording head according to Embodiment 2.

In the above-described embodiment, the piezoelectric active portion 32
0 is formed in a region facing the pressure generating chamber 12 apart from the peripheral wall of the pressure generating chamber 12, but in the present embodiment, the piezoelectric film 70 and the upper electrode film 80 constituting the piezoelectric active portion 320 are The configuration is the same as that of the first embodiment, except that the connecting portion 321 is continuously extended to the peripheral wall. A thick film portion 360A made of a relatively thick lower electrode film 60 is provided on both sides in the width direction of the piezoelectric active portion 320 and the connection portion 321 at the end of the pressure generating chamber 12 near the connection portion 321. ing. In this case, the vicinity of the illustrated region D is a vibration restricting portion. That is, the cross section taken along the line EE ′ and the cross section taken along the line FF ′ are the same as those shown in FIGS. 6B and 6C, respectively, and the lower electrode film removing portions 350 are formed on both sides of the piezoelectric active portion 320. The lower electrode film 60 is formed on both sides of the end portion of the body active portion 320 to form a thick film portion 360A.

In such a configuration, when the piezoelectric element is driven, the inside of the pressure generating chamber 12 and the boundary between the peripheral wall and the pressure generating chamber 12 are gradually bent toward the pressure generating chamber. Stress is reduced, breakage such as cracks is prevented, and durability is improved.

In order to achieve such an effect,
In the present embodiment, the length of the vibration restricting portion, that is, the distance from the end of the lower electrode film removing portion 350 to the end of the pressure generating chamber 12 (region D in the figure) is 1/1 / the width of the pressure generating chamber 12. It is preferably two or more.

(Embodiment 3) FIG. 9 shows the shapes of a piezoelectric active portion and a pressure generating chamber of an ink jet recording head according to Embodiment 3 of the present invention.

The present embodiment is the same as the first embodiment except that the lower electrode film removing portion 350B is formed to extend in the longitudinal direction from both ends of the piezoelectric active portion 320. Therefore, at the end of the pressure generating chamber 12, a portion sandwiched between the lower electrode film removing portions 350B is a thick film portion 360B.

Therefore, by adopting such a structure, the vibration due to the voltage application is restricted only in the vicinity of both ends of the piezoelectric active portion 320 as in the first embodiment, and the displacement amount is relatively small. The amount of displacement at the end can be suppressed without significantly reducing the amount of displacement as a whole, and peeling and cracking of the end of the piezoelectric active portion 320 can be prevented. The thick film portion 360B may be provided at one end of the pressure generating chamber 12.

(Embodiment 4) FIG. 10 shows the shapes of a piezoelectric active portion and a pressure generating chamber of an ink jet recording head according to Embodiment 4 of the present invention.

In this embodiment, unlike the above-described embodiment, the lower electrode film removing portion 350C is provided in a U-shape along three edges except for one end of the pressure generating chamber 12. . Further, from one end where the lower electrode film removing portion 350C is not provided, the piezoelectric film 7 constituting the piezoelectric active portion 320 is formed.
Although the 0 and upper electrode films 80 are continuously extended to the peripheral wall, a portion extending from the vicinity of the peripheral wall to the peripheral wall is not a mere thick film portion but an inactive piezoelectric active portion 325. is there.

Here, as shown in the cross section taken along line HH ′ of FIG.
And the piezoelectric film 70 only, and the upper electrode film 80 is removed. Therefore, even if a voltage is applied to the piezoelectric active portion 320, it is not driven.

With such a structure, the vibration due to the application of the voltage is restricted only in the vicinity of the inactive piezoelectric active portion 325, and the displacement becomes relatively small, so that the displacement as a whole is greatly reduced. Therefore, the amount of displacement at the end can be suppressed, and peeling and cracking of the end of the piezoelectric active portion 320 can be prevented. Note that the inactive piezoelectric active portions 325 may be provided at both ends of the pressure generating chamber 12.

As shown in FIG. 10C, an inactive piezoelectric active portion 325A may be formed by providing an insulating layer 326 between the piezoelectric film 70 and the upper electrode film 80.

(Embodiment 5) FIG. 11 shows the shapes of a piezoelectric active portion and a pressure generating chamber of an ink jet recording head according to Embodiment 5 of the present invention.

In the present embodiment, the thick film portion 360 of the first embodiment is used.
Is the same as that of the first embodiment except that a thick film portion 95 of the insulator layer 90 is provided instead of the thin film portion to serve as a vibration regulating portion.

That is, as shown in the section II ′ of FIG. 11B, the insulator layer 90 having a normal thickness is formed on the upper electrode film 80 except for the both ends of the piezoelectric active portion 320. However, at both ends, J- in FIG.
As shown in the J ′ section, the thick insulator layer 95 is
0.

Therefore, when the piezoelectric active portion 320 is driven by applying a voltage, only the vibration at both ends is regulated, and the displacement becomes relatively small only in the vicinity of this portion. The amount of displacement at the end can be suppressed without greatly lowering the piezoelectric active portion 320.
Can be prevented from being peeled off or cracked at the ends.
The thick insulator layer 95 may be provided only at one end of the pressure generating chamber 12. The thick-film insulator layer 95 only needs to be relatively thicker than other portions. For example, another layer may be provided on the insulator layer 90.

(Embodiment 6) FIG. 12 shows the shapes of a piezoelectric active portion and a pressure generating chamber of an ink jet recording head according to Embodiment 6 of the present invention.

In the present embodiment, the thick film portion 36 of the lower electrode film 60 is used.
Embodiment 1 except that 0C is provided on both sides of a substantially central portion in the longitudinal direction of the piezoelectric active portion 320, and a U-shaped lower electrode film removing portion 350D is formed along the edge of the other pressure generating chamber 12. Is the same as

Therefore, by adopting such a structure, similarly to the first embodiment, the vibration due to the application of the voltage is regulated so as not to be unnecessarily large at the substantially central portion of the piezoelectric active portion 320. The peeling and cracking of the end of the piezoelectric active portion 320 can be prevented without greatly reducing the displacement as described above.

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

For example, in addition to the sealing plate 20 described above, the common ink chamber forming plate 30 may be made of glass ceramic, and the thin film 41 may be made of glass ceramic as a separate member. Changes are free.

In the above-described embodiment, the nozzle openings are formed on the end surface of the flow path forming substrate 10. However, the nozzle openings may be formed so as to be connected in a direction perpendicular to the surface.

FIG. 13 is an exploded perspective view of the embodiment configured as described above, and FIG. 14 is a cross-sectional view of the flow path. In this embodiment, the nozzle openings 11 are bored in the nozzle substrate 120 opposite to the piezoelectric element, and the nozzle communication ports 22 for communicating the nozzle openings 11 and the pressure generating chambers 12 are formed with the sealing plate 20 and the common ink chamber. It is arranged so as to penetrate the forming plate 30, the thin plate 41A, and the ink chamber side plate 40A.

This embodiment is different from the first embodiment in that
A is basically the same as the above-described embodiment except that the ink chamber side plate 40A and the ink chamber side plate 40A are separate members, and the opening is formed in the ink chamber side plate 40. Is omitted.

Here, also in this embodiment, as in the first to sixth embodiments, a vibration restricting portion is provided to partially restrict the vibration of the piezoelectric active portion, and peeling of both ends of the piezoelectric film is prevented. Cracks can be prevented.

Of course, it goes without saying that the above-described embodiments are more effective when implemented in combination as appropriate.

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

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

As described above, the present invention can be applied to ink-jet recording heads having various structures, as long as the gist of the present invention is not contradicted.

The ink jet recording head of each of these embodiments constitutes a part of a recording head unit having an ink flow path communicating with an ink cartridge or the like, and is mounted on an ink jet recording apparatus. FIG.
FIG. 1 is a schematic view showing an example of the ink jet recording apparatus.

As shown in FIG. 15, recording head units 1A and 1B having an ink jet recording head are
Cartridges 2A and 2B constituting ink supply means are provided detachably, and a carriage 3 on which the recording head units 1A and 1B are mounted is provided on a carriage shaft 5 attached to the apparatus main body 4 so as to be movable in the axial direction. I have. The recording head units 1A and 1B are, for example,
Each of them ejects a black ink composition and a color ink composition.

Then, the driving force of the driving motor 6 is transmitted to the carriage 3 via a plurality of gears and a timing belt 7 (not shown), so that the carriage 3 on which the recording head units 1A and 1B are mounted moves along the carriage shaft 5. Moved. On the other hand, the apparatus main body 4 is provided with a platen 8 along the carriage shaft 5, and a recording sheet S, which is a recording medium such as paper fed by a paper feed roller (not shown), is wound around the platen 8. It is designed to be transported.

[0105]

As described above, in the present invention,
By providing a vibration restricting portion that restricts the vibration of a part of the piezoelectric body active portion facing the pressure generating chamber, the vibration is partially restricted, and the piezoelectric body active portion is not greatly reduced without greatly reducing the entire displacement. Cracking or peeling of both ends of the portion can be prevented.

[Brief description of the drawings]

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

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

FIG. 3 is a view showing a modification of the sealing plate of FIG. 1;

FIG. 4 is a diagram showing a thin film manufacturing process according to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating a thin film manufacturing process according to the first embodiment of the present invention.

FIG. 6 is a plan view and a cross-sectional view illustrating a main part of the inkjet recording head according to the first embodiment of the present invention.

FIG. 7 is a view showing a thin film manufacturing process according to the first embodiment of the present invention.

FIG. 8 is a plan view of a main part of an ink jet recording head according to a second embodiment of the invention.

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

FIG. 10 is a plan view and a cross-sectional view of a main part of an inkjet recording head according to a fourth embodiment of the invention.

FIGS. 11A and 11B are a plan view and a cross-sectional view of a main part of an inkjet recording head according to a fifth embodiment of the invention.

FIG. 12 is a main part plan view showing an ink jet recording head according to Embodiment 6 of the present invention.

FIG. 13 is an exploded perspective view of an ink jet recording head according to another embodiment of the present invention.

FIG. 14 is a sectional view showing an ink jet recording head according to another embodiment of the present invention.

FIG. 15 is a schematic diagram of an ink jet recording apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 flow path forming substrate 11 nozzle opening 12 pressure generating chamber 50 elastic film 60 lower electrode film 70 piezoelectric film 80 upper electrode film 90 insulator layer 95 thick insulator layer 100 lead electrode 300 piezoelectric element 320 piezoelectric active part 350, 350A Lower electrode film removal part 360, 360A Thick film part

Claims (14)

[Claims] A pressure generating chamber that communicates with a nozzle opening; and a piezoelectric element formed on the vibration plate, wherein the piezoelectric element is provided in a region facing the pressure generating chamber. A piezoelectric active portion, wherein the vibrating plate is thinner than a portion corresponding to the piezoelectric active portion, at least in a portion along the edge of the pressure generating chamber on both widthwise sides of the piezoelectric active portion. In an ink jet recording head having a thin portion, an ink jet recording head is provided, in which at least a part near the end of the piezoelectric active portion or at both sides in the width direction is provided with a vibration restricting portion that restricts the movement of the diaphragm. Recording head. 2. The vibration control unit according to claim 1,
An ink jet recording head, which is provided on the outer side and both sides in the longitudinal direction of the end of the piezoelectric active portion. 3. The vibration control device according to claim 1, wherein
An ink jet recording head, which is provided on a longitudinally outer side of an end of the piezoelectric active portion, and wherein the diaphragms on both sides of the vibration restricting portion are the thin portions. 4. The apparatus according to claim 1, wherein the vibration restricting section comprises:
An ink jet recording head provided on a part of both sides in the width direction of the piezoelectric active portion. 5. The ink jet recording head according to claim 1, wherein the vibration restricting portion is a thick portion where the thickness of the diaphragm is larger than the thin portion. 6. The ink jet recording head according to claim 1, wherein the vibration restricting portion has another layer that restricts vibration of the vibration restricting portion. 7. The ink jet recording head according to claim 1, wherein the vibration restricting portion includes an inactive portion having an inactive piezoelectric layer on the vibration plate. 8. The inactive portion according to claim 7, wherein the inactive portion is a portion where the upper electrode is removed on the piezoelectric layer or a portion where the upper electrode is provided on the piezoelectric layer via an insulating layer. An ink jet recording head, characterized in that: 9. The piezoelectric active part according to claim 1, wherein the piezoelectric active part is provided apart from a peripheral wall of the pressure generating chamber, and a connection between a lead electrode and an upper electrode is provided on an upper surface of the piezoelectric active part. An ink jet recording head comprising a contact portion for performing the following. 10. The piezoelectric element according to claim 9, wherein an insulating layer is formed on an upper surface of the piezoelectric active portion, and a contact portion for connecting a lead electrode and the upper electrode is a contact hole formed in the insulating portion. An ink jet recording head formed in the inside. 11. The piezoelectric body according to claim 1, wherein the piezoelectric layer and the upper electrode constituting the piezoelectric active portion face the peripheral wall of the pressure generating chamber from a longitudinal end of the piezoelectric active portion. An ink jet recording head provided continuously up to an area. 12. The method according to claim 11, wherein the vibration restricting portion is provided at a portion where the piezoelectric layer and the upper electrode are continuously provided up to a region facing the peripheral wall of the pressure generating chamber. Inkjet recording head. 13. The pressure generating chamber according to claim 1, wherein the pressure generating chamber is formed on a silicon single crystal substrate by anisotropic etching, and each layer of the piezoelectric element is formed by film formation and lithography. An ink jet recording head, comprising: 14. An ink jet recording apparatus comprising the ink jet recording head according to claim 1.