WO2004098894A1

WO2004098894A1 - Fluid jetting head and fluid jetting device

Info

Publication number: WO2004098894A1
Application number: PCT/JP2004/006332
Authority: WO
Inventors: Shiro Yazaki
Original assignee: Seiko Epson Corporation
Priority date: 2003-05-06
Filing date: 2004-04-30
Publication date: 2004-11-18
Also published as: JP4484821B2; JPWO2004098894A1

Abstract

A fluid jetting head capable of preventing crosstalk from occurring and providing stable fluid jetting characteristics and a fluid jetting device, the fluid jetting head wherein partition walls (11) on the lateral both sides of pressure generating chambers (12) are extended near the pressure generating chamber (12) side end part of a reservoir part (32), and fluid supply passages (14) formed to have a width smaller than the width of the pressure generating chambers (12) in communication with the pressure generating chambers (12) and communication passages (100) allowing the fluid supply passages (14) to communicate with a communication part (13) and formed to have a width larger than the width of the fluid supply passages (14) are provided by dividing each of the pressure generating chambers (12) by the partition walls (11) (wall parts 11a). Thus, the occurrence of the crosstalk can be prevented and the stable fluid jetting characteristics can be provided.

Description

Liquid injection head and liquid injection device

Technical field

The present invention relates to a liquid ejecting head and a liquid ejecting apparatus that eject droplets, and more particularly, to an ink jet recording head and an ink jet recording apparatus that eject ink droplets from a nozzle opening. Background art

A part of the pressure generating chamber that communicates with the nozzle opening for discharging ink droplets

An ink jet recording head has been put to practical use in which the diaphragm is deformed by a piezoelectric element to press the ink in the pressure generating chamber to discharge ink droplets from nozzle openings. For example, as such an ink jet recording head, a uniform piezoelectric material layer is formed by a film forming technique over the entire surface of a diaphragm, and this piezoelectric material layer is applied to a pressure generating chamber by a lithographic method. There is a type in which a piezoelectric element is formed so as to be divided into different shapes and independent of each pressure generating chamber. Such a piezoelectric element has a problem that it tends to burst due to an external environment such as moisture (humidity). For example, since the reservoir, which is a common liquid chamber of the pressure generating chamber, is filled with ink containing water, it is necessary to secure a certain distance between the reservoir and the piezoelectric element.

Here, for example, Japanese Patent Application Laid-Open No. 2000-296666 discloses a structure for preventing the destruction of the piezoelectric element, a flow path forming substrate in which a pressure generating chamber is formed, A structure is disclosed in which a reservoir forming substrate having a piezoelectric element holding portion is joined, and the piezoelectric element is sealed in the piezoelectric element holding portion. Specifically, a flow path forming substrate provided with a plurality of pressure generating chambers communicating with the nozzle openings, a piezoelectric element for generating a pressure change in each pressure generating chamber, and a reservoir as a common liquid chamber for the pressure generating chambers And a nozzle plate having a nozzle opening joined to the other surface side of the flow path forming substrate. A piezoelectric element holding portion capable of sealing the space is provided in a region facing the piezoelectric element on the reservoir forming substrate, with a space secured so as not to hinder the movement of the piezoelectric element. ing. An ink supply path for supplying the ink in the reservoir to each of the pressure generating chambers is provided at one longitudinal end of each of the pressure generating chambers.

However, even in the above-described head structure in which the piezoelectric element is formed in the piezoelectric element holding portion, the moisture contained in the ink in the reservoir passes through the joint between the flow path forming substrate and the reservoir forming substrate, and the piezoelectric element is held. There is a possibility that the piezoelectric element may break into the inside of the unit and be destroyed. Therefore, in any case, it is necessary to sufficiently secure the distance between the piezoelectric element and the reservoir, specifically, the length of the joint between the piezoelectric element holding part and the reservoir. On the other hand, in order to improve the ink supply characteristics, it is necessary to shorten the length of the ink supply path. For this reason, if a sufficient connection between the piezoelectric element holding portion and the reservoir is to be ensured, only the flow path forming substrate is formed between the ink supply path and the reservoir in the direction in which the pressure generating chambers are juxtaposed. Is formed.

In the ink jet recording head having such a structure, the ink in the pressure generation chamber flows out to the reservoir side via the ink supply path together with the ink discharge because the pressure is generated in the pressure generation chamber at the time of ink discharge. For this reason, if there is a space between each ink supply path and the reservoir, which is composed only of the flow path forming substrate, the ink flowing out of each pressure generating chamber to the reservoir side will be in the pressure generating chamber in that space. Flow in both directions (the direction in which nozzles and nozzles are arranged) and the longitudinal direction of the pressure generating chamber (the direction orthogonal to the direction in which nozzles are arranged). For this reason, the flow of the ink flowing out of the adjacent pressure generating chambers interferes with each other, so-called crosstalk occurs, and there is a problem that stable ink ejection characteristics cannot be obtained.

If the joint between the piezoelectric element holding portion and the reservoir is shortened in accordance with the length of the ink supply path, the joint area between the flow path forming substrate and the reservoir forming substrate is reduced, and sufficient joining strength is obtained. Can not be obtained. Also, if the ink supply path is made relatively long in order to secure the connection between the piezoelectric element holding section and the reservoir, the cross-sectional area of the ink supply path becomes substantially large, and the meniscus attenuation characteristics deteriorate. Therefore, there is a problem that high-speed driving becomes impossible.

Such problems exist not only in the ink jet recording head for ejecting ink but also in other liquid ejecting heads for ejecting liquids other than ink. Disclosure of the invention

In view of such circumstances, an object of the present invention is to provide a liquid ejecting head and a liquid ejecting apparatus capable of preventing occurrence of crosstalk and obtaining stable liquid ejection characteristics.

According to a first aspect of the present invention for solving the above-mentioned object, there is provided a flow path forming substrate in which a plurality of pressure generating chambers communicating with a nozzle opening are arranged in parallel, and a flow path forming substrate provided through a diaphragm. A piezoelectric element comprising an electrode, a piezoelectric layer, and an upper electrode; and a reservoir which is joined to a surface of the flow path forming substrate on the piezoelectric element side and constitutes a part of a reservoir which is a common liquid chamber of each pressure generating chamber. A reservoir formed substrate provided with a reservoir, wherein the reservoir is composed of the reservoir and a communication portion provided in the flow path substrate, and partitions on both sides in the width direction of the pressure generating chamber are formed in the reservoir. A liquid supply passage communicating with the pressure generation chamber and having a width smaller than the width of the pressure generation chamber by extending to a portion near the end of the pressure generation chamber on the side of the pressure generation chamber; And a liquid supply passage for communicating with the communication portion. And a communication passage having a width larger than the width of the pressure generation chamber.

In the vigorous first aspect, crosstalk is prevented from occurring by separately providing different paths between each liquid supply path and the reservoir, and stable liquid ejection characteristics can be obtained.

A second aspect of the present invention, first in one aspect, the communication path liquid jet head relationship between the width _{W l} and width w ₂ of the pressure generating chamber and satisfies the _{W l ≥w} ₂ of Nime

In the second aspect, desired liquid supply characteristics can be secured. ―

A third aspect of the present invention, in the first or second aspect, wherein the relationship between the width _{W l} and before Symbol width w ₃ of the liquid supply path of the communication passage meet _{W l} ≥ 2 X w ₃ In the liquid jet head. '

In the third aspect, by providing the communication passage having a predetermined size, desired liquid supply characteristics can be secured.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the length of the communication path Is not less than the thickness of the flow path forming substrate. In the fourth aspect that is powerful, by providing a communication path having a predetermined length or more, the occurrence of crosstalk is more effectively prevented.

In a fifth aspect of the present invention, in any one of the first to fourth aspects, a distance between an end of the partition wall on the reservoir section side and the reservoir section is shorter than a thickness of the flow path forming substrate. The liquid ejection head is characterized in that:

In the fifth aspect, since the end of the partition on the side of the reservoir is extended to near the end of the reservoir on the side of the pressure generating chamber, the occurrence of crosstalk is prevented.

A sixth aspect of the present invention is the liquid jet head according to any one of the first to fifth aspects, wherein the piezoelectric element is covered with an insulating film made of an inorganic insulating material.

In the sixth aspect, since the piezoelectric layer is covered with the insulating film made of the inorganic insulating material having a low moisture permeability, the piezoelectric layer (piezoelectric element) due to moisture (moisture) is deteriorated. Destruction) is reliably prevented over a long period of time.

A seventh aspect of the present invention, in the sixth aspect, wherein the insulating film is in the head to the liquid jet, characterized in that it consists of A l ₂ 0 _3.

In the vigorous seventh aspect, since the piezoelectric element is covered with the insulating film made of a metal oxide having a very low moisture permeability, the piezoelectric layer can be reliably prevented from being broken due to the external environment.

According to an eighth aspect of the present invention, in any one of the first to seventh aspects, the reservoir forming substrate can secure a space in a region facing the piezoelectric element to such an extent that the movement of the piezoelectric element is not hindered. The liquid ejecting head is provided with a piezoelectric element holding portion, and a region of the reservoir forming substrate between the piezoelectric element holding portion and the reservoir portion is a joint portion with the flow path forming substrate. .

In the eighth aspect, the partition wall is extended to the vicinity of the boundary between the flow path forming substrate and the reservoir forming substrate on the side of the reservoir section, whereby the rigidity of both substrates is ensured, and the liquid supply path is formed. By separately providing communication paths between the communication part and the communication part, occurrence of crosstalk is prevented.

According to a ninth aspect of the present invention, in the eighth aspect, the partition wall side of the reservoir portion is provided. The end is in the liquid projection head, which is located in a region facing the joining portion.

According to the ninth aspect, it is possible to reliably prevent the end of the partition from protruding into the communication portion, which is an obstacle to forming the reservoir.

A tenth aspect of the present invention is the liquid jet head according to the eighth or ninth aspect, wherein the length of the joining portion is at least 200 μπι.

In the tenth aspect, the length of the joint portion with the reservoir forming substrate on one end side in the longitudinal direction of the pressure generating chamber of the flow channel forming substrate is set to a predetermined amount or more, so that the liquid contained in the reservoir can be included. Moisture that does not substantially permeate into the piezoelectric element holding portion, and the rupture of the piezoelectric element is prevented. In addition, the rigidity between the flow path forming substrate and the reservoir forming substrate is increased.

According to a eleventh aspect of the present invention, in any one of the eighth to tenth aspects, there is provided an atmosphere opening hole having one end communicating with the piezoelectric element holding portion and the other end being open to the atmosphere. The liquid jet head is characterized in that:

In the eleventh aspect, since the piezoelectric element holding portion is opened to the atmosphere through the air opening hole, no dew condensation occurs in the piezoelectric element holding portion, and the piezoelectric element breaks down due to the condensation. It is reliably prevented.

A twenty-second aspect of the present invention is the liquid jet head according to any one of the first to eleventh aspects, wherein the thickness of the flow path formation substrate is 100 πι or less. is there. In the first and second aspects, the pressure generating chambers can be arranged at a relatively high density while maintaining the rigidity of the partition wall between the adjacent pressure generating chambers.

According to a thirteenth aspect of the present invention, in any one of the first to thirteenth aspects, the pressure generation chamber is formed by anisotropic etching on a silicon single crystal substrate. In the head. 'In the thirteenth aspect, a liquid jet head having a high-density nozzle opening can be relatively easily manufactured.

A fifteenth aspect of the present invention is a liquid ejecting apparatus including the liquid ejecting bed according to any one of the first to thirteenth aspects.

In the fourteenth aspect, the liquid discharge characteristics are substantially stable and the reliability is improved. Liquid ejecting apparatus can be realized. Brief description of the drawings.

FIG. 1 is an exploded perspective view of a head according to the first embodiment.

FIG. 2 is a plan view and a cross-sectional view of the head according to the first embodiment.

FIG. 3 is a cross-sectional view illustrating a flow channel structure of the head according to the first embodiment.

FIG. 4 is a sectional view of another head according to the first embodiment.

FIG. 5 is a diagram showing the relationship between the number of simultaneous ejections and the crosstalk rate.

FIG. 6 is a cross-sectional view showing a manufacturing process of the head according to the first embodiment.

FIG. 7 is a sectional view showing a manufacturing process of the head according to the first embodiment.

FIG. 8 is a schematic diagram showing an example of a recording head. BEST MODE FOR CARRYING OUT THE INVENTION

'Hereinafter, the present invention will be described in detail based on embodiments.

(Embodiment 1)

FIG. 1 is an exploded perspective view of an ink jet recording head according to Embodiment 1, and FIG. 2 is a schematic plan view of FIG. 1 and a cross-sectional view taken along line AA ′. As shown in the figure, the flow path forming substrate 10 is composed of a silicon single crystal substrate having a plane orientation (110) in this embodiment, and has elasticity composed of silicon dioxide formed in advance by thermal oxidation on both surfaces. A film 50 and a mask pattern 51 used as a mask when forming a pressure generating chamber described later are provided.

The pressure generating chambers 12 divided by the plurality of partition walls 11 are arranged in the width direction on the flow path forming substrate 10 by anisotropic etching from the other side, that is, the nozzle The pressure generating chamber 12, the ink supply path 14, and the communication path 1 are arranged at one end in the longitudinal direction (the direction orthogonal to the direction in which the nozzles are arranged). 0 and a communication portion 13 forming a part of a reservoir 11 ′ ′ 0 serving as a common ink chamber for each pressure generating chamber 12 are formed.

The ink supply path 14 communicates with one longitudinal end of the pressure generating chamber 12 and has a smaller cross-sectional area than the pressure generating chamber 12. For example, in the present embodiment, the ink supply path 1 4 is formed to have a width smaller than the width of the pressure generating chamber 12 by narrowing the flow path on the side of the pressure generating chamber 12 between the reservoir 110 and each of the pressure generating chambers 12 in the width direction. . In this embodiment, as described above, in the present embodiment, the ink supply path 14 is formed by reducing the width of the flow path from one side. However, the ink supply path is formed by reducing the width of the flow path from both sides. Is also good. Further, each communication passage 100 is formed by extending the partition walls 11 on both sides in the width direction of the pressure generating chamber 12 to the communication portion 13 side to define a space between the ink supply passage 14 and the communication portion 13. It is formed by things. The communication passage 100 will be described later in detail.

Here, the anisotropic etching is performed by utilizing the difference in the etching rate of the silicon single crystal substrate. For example, in the present embodiment, when a silicon single crystal substrate is immersed in an alkaline solution such as KOH, the substrate is gradually eroded, and the first (111) surface is perpendicular to the (110) surface. A second (.1 1 1) plane which forms an angle of about 70 degrees with the (1 1 1) plane of the above and forms an angle of about 35 degrees with the above (1 110) plane appears, and (1 1 This is performed by using the property that the etching rate of the (1 1 1) plane is about 1Z180 compared to the etching rate of the 0) plane. By such anisotropic etching, precision processing is performed based on parallelogram-shaped depth processing formed by two first (1 1 1) planes and two diagonal second (1 1 1) planes. The pressure generating chambers 12 can be arranged at a high density.

In the present embodiment, the long side of each pressure generating chamber 12 is formed by the first (11 1) surface, and the short side is formed by the second (11 1) surface. The pressure generating chamber 12 is formed by etching until it reaches the elastic film 50 substantially through the flow path forming substrate 10. Here, the amount of the elastic film 50 which is affected by the solution for etching the silicon single crystal substrate is extremely small.

The thickness of the flow path forming substrate 10 may be selected in accordance with the arrangement density of the pressure generating chambers 12, and the arrangement density of the pressure generating chambers 12 may be, for example, per inch. If the number is about 180 (180 dpi), the thickness of the flow path forming substrate 10 may be about 220 μm. For example, when the array is arranged at a relatively high density of 200 dpi or more. In this case, it is preferable that the thickness of the flow path forming substrate 10 is 100 μΐη or less, particularly, 70 zm. This is because the arrangement density can be increased while maintaining the rigidity of the partition wall 11 between the adjacent pressure generating chambers 12. Further, a nozzle plate 20 having a nozzle opening 21 formed therein is joined to the opening surface side of the flow path forming substrate 10. Such a nozzle plate 20 has a thickness of, for example, 0.05 to 1 mm and is made of glass ceramics, a silicon single crystal substrate, or stainless steel. The nozzle plate 20 entirely covers one surface of the flow path forming substrate i0 with one surface, and also serves as a reinforcing plate for protecting the flow path forming substrate 10 from impacts and external forces. 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 21 for ejecting the ink droplet depend on the amount of the ejected ink droplet, the ejection speed, and the ejection frequency. Optimized accordingly. For example, when recording 360 ink drops per inch, the nozzle opening 21 needs to be formed with a diameter of several tens of μm with high accuracy.

On the other hand, on the side opposite to the opening surface of the flow path forming substrate 10, an insulating film 50 having a thickness of, for example, 0.4 μππι is placed on an elastic film 50 having a thickness of, for example, about 1.0 μm. Through the body film 55, the lower electrode film 60 having a thickness of, for example, about 0.2 μπα, the piezoelectric layer 70 having a thickness of, for example, about 1.2 μππ, and the thickness For example, a piezoelectric element 300 is formed by laminating an upper electrode film 80 of about 0.05 / xm in a process described later. Here, the piezoelectric element 300 refers to a portion including the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80. Generally, any one of the electrodes of the piezoelectric element 300 is used as a common electrode, and the other electrode and the piezoelectric layer 70 are patterned for each of the pressure generating chambers 12. Here, a portion which is constituted by either one of the patterned electrodes and the piezoelectric layer 70 and in which a piezoelectric strain is generated by applying a voltage to both electrodes is referred to as a piezoelectric active portion. 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 a separate electrode of the piezoelectric element 300. There is no problem even if it is reversed. In any case, a piezoelectric active portion is formed for each pressure generating chamber. Further, here, the piezoelectric element 300 and a vibration plate whose displacement is generated by driving the piezoelectric element 300 are collectively referred to as a piezoelectric actuator. In the example described above, the elastic film 50, the insulator film 55, and the lower electrode film 60 function as a diaphragm.

Examples of the material of the piezoelectric layer 70 include a ferroelectric piezoelectric material such as lead zirconate titanate (PZT), niobium, nickel, magnesium, bismuth, and iron. A relaxor ferroelectric or the like to which a metal such as rubidium is added may be used. Its composition, characteristics of the piezoelectric element 70 may be chosen, as appropriate, in consideration of the use and the like, for example, P b T i O a ( PT), P b Z r 0 3. (PZ), P b (Z r _{_{x T i! _ x) 0}} 3 (P ZT), P b (M g! / 3 N b 2/3) 0 3 -P b T i 0 3 (PMN-PT), P b (Z n! / _{3 N b 2/3) 0} 3 -P b T i 0 3 (P ZN-PT), P b (N i xx a Nb 2/3) 0 3 -P b T i 0 3 (PNN-PT), P b (I n _{1 χ 2} Nb '/ 2) 0 ₃ -P b T i O ₃ (PI N-PT), P b (S _{C l} / ₃ T a _1/2 ) O a -P b T i 0 ₃ (P ST— PT), P b (S c _1/3 Nb _1/2 ) 0 ₃ -P b T i〇 ₃ (P SN— PT), B i S c 0 ₃ — P b T i 0 _{3 (BS- PT), B i} Yb 0 3 -P b T i 0 3 (BY- PT) , and the like.

One end of each upper electrode film 80, which is an individual electrode of the piezoelectric element 300 composed of the piezoelectric layer 70, is made of, for example, gold (Au) or the like, and one end of which is a through hole 33 described later. The lead electrode 90 extended to the region corresponding to the above is connected. Further, the piezoelectric element 300 is covered with an insulating film 200 made of an inorganic insulating material. For example, in the present embodiment, the connection portions 60 a, in which each layer constituting the piezoelectric element 300 and the pattern region of the lead electrode 90 are connected to a drive IC (not shown) of the lower electrode film 60 and the lead electrode 90 via connection wiring, Except for the region facing 90a, it is covered with the insulating film 200. That is, the surfaces (the upper surface and the end surface) of the lower electrode film 60, the piezoelectric layer 70, the upper electrode film 80, and the lead electrode 90 in the pattern region are covered with the insulating film 200.

Here, as the material of such an insulating film 200, if an inorganic insulating material is not limited especially, for example, acid I arsenide aluminum (A l ₂ 0 _3), tantalum pentoxide (T a ₂ 0 ₅ ), although silicon (S i 0 ₂₎ or the like dioxide and the like, it is preferable to use a suitably acid Ihiarumi Niumu (a l. 0 _3). In particular, when aluminum oxide is used, even if the insulating film 200 is formed as a thin film having a thickness of about 100 nm, it is possible to sufficiently prevent moisture permeation in a high humidity environment. When an organic insulating material such as a resin is used as the material of the insulating film, for example, the same thickness as the insulating film of the inorganic insulating material is used.

'Well, we cannot fully prevent water permeation. Further, if the thickness of the insulating film is increased in order to prevent moisture permeation, there is a possibility that the movement of the piezoelectric element may be hindered. Since the insulating film 200 made of such an inorganic insulating material has extremely low moisture permeability even in a thin film, the insulating film 200 allows the lower electrode film 60, the piezoelectric layer 70, and the upper electrode By covering the surfaces of the electrode film 80 and the lead electrode 90, it is possible to prevent rupture due to moisture (moisture) of the piezoelectric layer 70. In addition, by covering the layers constituting the piezoelectric element 300 and the surface of the lead electrode 90 except for the connection portions 60a and 90a, these layers and the insulating film 200 are formed. Even if moisture invades from between, it is possible to prevent moisture from reaching the piezoelectric layer 7, and it is possible to more reliably prevent breakage due to moisture in the piezoelectric layer 70.

In addition, a reservoir forming substrate 30 is bonded on the flow path forming substrate 10 on which the piezoelectric elements 300 are formed. The reservoir forming substrate 30 is provided with a reservoir portion 32 that constitutes a part of the reservoir 110, and is provided outside the pressure generating chambers 12 in the longitudinal direction. In the present embodiment, the reservoir portion 32 is formed so as to penetrate the reservoir forming substrate 30 in the thickness direction and to extend in the width direction of the pressure generating chamber 12. The elastic film 50 and the insulator film 5 Reservoirs 110 which are communicated with the communicating portions 13 of the flow path forming substrate 10 via the through portions provided in 5 and serve as common ink chambers of the pressure generating chambers 12 are respectively formed. ing. The thickness of the reservoir forming substrate 30 is, for example, 200 to 400 μπι.

Further, in the present embodiment, such a reservoir forming substrate 30 is provided with a piezoelectric element holding portion 31 capable of securing a space in a region facing the piezoelectric element 300 so as not to hinder its movement. I have. That is, the piezoelectric element 300 is formed in the piezoelectric element holding section 31.

Further, in the present embodiment, the reservoir forming substrate 30 is provided with an atmosphere opening hole 31a whose one end communicates with the piezoelectric element holding portion 31 and whose other end is open to the atmosphere. That is, the piezoelectric element holding portion 31 is opened to the atmosphere through the air opening hole 3 ia without sealing the piezoelectric element 300. As a result, it is possible to prevent dew condensation from occurring in the piezoelectric element holding portion 31, and it is possible to reliably prevent the piezoelectric element 300 from breaking due to the dew condensation. The other end of the open-to-air hole 31 a is provided, for example, on the surface of the reservoir forming substrate 30 on the side opposite to the piezoelectric element holding portion 31 side. It is open to the atmosphere in a region that does not interfere with the drive IC mounted on the device. Further, the reservoir 110 of the reservoir forming substrate 30 and the pressure generating chambers 12 of the flow path forming substrate 10 communicate with each other via the ink supply path 14 and the communication path 100. Here, the communication passage 100 will be described in detail with reference to FIG. FIG. 3 is a cross-sectional view showing the flow path structure of the ink jet recording head according to the first embodiment. As shown in FIG. 3, the communication paths 100 are provided independently for each of the pressure generating chambers 12 between each ink supply path 14 and the communication section 13, and each of the pressure supply chambers An individual flow path is formed between the generation chamber 12 and the reservoir 110.

Specifically, the partition walls 11 on both sides in the width direction of the pressure generation chamber 12 are extended to near the end of the reservoir section 32 on the pressure generation chamber 12 side. That is, in the present embodiment, the partition walls 11 on both sides in the width direction of the pressure generation chamber 12 extend to the vicinity of the end on the side of the reservoir part 32 at the junction between the flow path forming substrate 10 and the reservoir forming substrate 30. Is established. By extending each partition 11 in this manner, a wall 11a is formed between each ink supply path 14 and the communication portion 13 and ink is supplied by the wall 11a. Each communication path 100 is formed by partitioning a space between the path 14 and the communication portion 13.

The width of the communication path 1 00 is preferably a relatively wider, for example, the relationship between the width w ₂ of the width _Wl and the pressure generating chamber 1 2 of the communication passage 1 00, satisfy the _Wl ≥W ₂ Is desirable. Furthermore, the relationship between the width w ₃ of違通path 1 00 having a width _Wl and the ink supply path 14, it is desirable that meets w ₁ ≥ 2 Xw _3. Thus, by providing the communication path 100 with a predetermined size, desired ink supply characteristics can be obtained. Here, as the ink, an ink having a viscosity in a range of about 2.0 to 12.2 OmPa · sec in a use environment in a temperature range of about 10 to 40 ° C is used. Specifically, a normal ink has a viscosity in the range of about 2.0 to 6.5 mPa · sec, and a high-viscosity pigment ink has a viscosity of about 8 to 1 lm. Sec within the range of Pa.sec.

As described above, in the present embodiment, the region facing the joint with the reservoir forming substrate 30 at one end in the longitudinal direction of the pressure generating chamber 12 of the flow path forming substrate 10, specifically, each ink supply Between the channel 14 and the reservoir 110, the wall 1 1a creates a pressure chamber 1 Since the communication path 100 is provided with a predetermined width independently for each of the two inks, the ink flowing from the adjacent ink supply path 14 to the reservoir 110 side during ink discharge may interfere with each other. Therefore, the occurrence of crosstalk can be prevented. Therefore, regardless of whether or not ink droplets are ejected from the adjacent nozzle opening 21, stable ink ejection characteristics can be obtained. In addition, the ink supply path 14 can be shortened without generating crosstalk, and the high-speed driving of the head can be realized by substantially increasing the meniscus attenuation characteristics.

Further, in the present invention, it is preferable that the length of the communication passage 100 (see FIG. 3) be equal to or longer than a predetermined length by providing the wall portion 11a with a predetermined length or longer. It is preferable that the length of the communication passage 100 be equal to or greater than the thickness of the passage forming substrate 10. Note that the length 1 ^ of the communication passage 100 corresponds to a region where the width _Wl of the communication passage 100 is secured. As a result, at the time of ink ejection, the ink flowing out from the adjacent ink supply path 14 to the reservoir 110 side flows separately to the reservoir 110 along the communication path 100, so that the inks flow out from each other. Therefore, the occurrence of crosstalk can be effectively prevented without interfering with the communication. For example, in the present embodiment, the thickness of the flow path forming substrate 10 is set to about 70 μππ, and the length of the communication path 100 is set to about 100 μπη. By setting the length of the communication path 100 to be equal to or greater than the thickness of the flow path forming substrate 10 in this manner, the piezoelectric element holding portion 31 and the reservoir portion 3 of the reservoir forming substrate 30 described later in detail will be described. 2, the length L of the joint portion with the flow path forming substrate 10 can be sufficiently ensured.

Here, the length L (see FIG. 2) of the joint between the flow path forming substrate 10 and the reservoir forming substrate 30 between the piezoelectric element holding portion 31 and the reservoir 110 is 200 / m or more. As a result, the distance between the piezoelectric element holding portion 31 and the reservoir portion 32 can be ensured, and the water contained in the ink in the reservoir 110 can be prevented from entering the piezoelectric element holding portion 31. It is possible to reliably prevent the piezoelectric element 300 from bursting. In addition, since the joint area between the flow path forming substrate 10 and the reservoir forming substrate 30 is increased, there is also an effect that the flexibility of both substrates can be sufficiently ensured and the durability of the head can be improved.

Note that the end of the wall portion 11 a forming the communication passage 100 on the reservoir portion 32 side is in a region opposed to a joint portion where the flow passage forming substrate 10 and the reservoir forming substrate 30 are joined. Is preferably located. If the end of the wall portion 11a protrudes into the communication portion 13, the elastic film 50 and the insulator film 55 separating the communication portion 13 and the reservoir portion 32 will be broken in a manufacturing process described later. This is an obstacle to the formation of the reservoir 110.

In the present invention, it is preferable to reduce the distance between the end of the partition 11 (wall 11a) on the reservoir 32 side and the reservoir 32. Specifically, as shown in FIG. 4, the distance S between the end of the partition 11 on the side of the reservoir 32 and the reservoir 32 is set shorter than the thickness of the flow path forming substrate 10. Is preferred. As a result, the partition wall 11 extends to near the end of the reservoir section 32 on the pressure generating chamber 12 side, and the space between the ink supply path 14 and the communication section 13 (reservoir 110), specifically, Specifically, the space formed only by the flow path forming substrate 10 and extending in the width direction of the pressure generating chamber 12 can be divided and reduced by the wall portion 1 l.a, so that the flow out of the adjacent communication path 10 OA It is possible to reduce the interference between the inks, and to prevent the occurrence of crosstalk.

Further, in a region of the reservoir forming substrate 30 opposite to the reservoir portion 32, a through hole 33 penetrating the reservoir forming substrate 30 in the thickness direction is provided. The lead electrode 90 pulled out from each piezoelectric element 300 is exposed in the through hole 33 near the end. As such a reservoir forming substrate 30, it is preferable to use a material having substantially the same thermal expansion coefficient as that of the flow path forming substrate 10, for example, glass, a ceramic material, or the like. It was formed using a silicon single crystal substrate of the same material as 10.

Note that a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is joined to a region corresponding to the reservoir portion 32 of the reservoir forming substrate 30. Here, the sealing film 41 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide (PPS) film having a thickness of 6 μππι). Thus, one surface of the reservoir 32 is sealed. The fixing plate 42 is formed of a hard material such as a metal (for example, stainless steel (SUS) having a thickness of 30 μπα). The area of the fixing plate 42 facing the reservoir 110 is an opening 43 completely removed in the thickness direction, so that one surface of the reservoir 110 has a flexible seal. It is sealed only by the blocking film 41. The ink jet recording head of the present embodiment described above takes in ink from an ink supply means (not shown), fills the inside from the reservoir 110 to the nozzle opening 21 with ink, and then drives the drive IC (not shown). A driving voltage is applied between the lower electrode film 60 and the upper electrode film 80 corresponding to the pressure generating chambers 12 according to the driving signals of the elastic film 50, the insulator film 55, and the piezoelectric element. By displacing 300, the pressure in each pressure generating chamber 12 increases, and ink droplets are ejected from nozzle opening 21. '' (Test example)

Here, a space provided with only a flow path forming substrate in a direction in which the pressure generating chambers are arranged between the ink supply path and the reservoir without providing a communication path, and a head provided with a communication path (Example). A head provided with (Comparative Example) was prepared, and a test was performed to compare the crosstalk rates (%) of the two. 'Specifically, one reference nozzle (reference nozzle) is determined, and the ejection speed when ink is ejected only from this reference nozzle is set to the reference value “0” (zero). When the ink was simultaneously ejected from the nozzles, the ejection speed of the ink droplet ejected from the reference nozzle was measured. Then, while increasing the number of nozzles for simultaneous ink discharge by two, the transition (change rate) of the discharge speed at the reference nozzle was examined. Figure 5 shows the results. In FIG. 5, the rate of change of the discharge speed at the reference nozzle is shown as a crosstalk rate (%).

As shown in FIG. 5, in the head of the comparative example, when the number of simultaneous ejections becomes about 20, the rate of increase in the ejection speed of the reference nozzle, that is, the crosstalk rate, increases to about 20%. Has increased to nearly 25%. On the other hand, in the head of the embodiment, when the number of simultaneous ejections becomes about 20 pieces, it increases to about 15% with the same transition as the comparative example, but thereafter, the range of less than 20% It has been stable within. As is clear from these results, it was found that the crosstalk ratio of the head of the example was relatively reduced by about 0.10% as compared with the head of the comparative example. Therefore, by providing the communication path as in the head of the embodiment, it is possible to reduce the occurrence of crosstalk during ink ejection.

As described above, an example of the ink jet recording head of the present invention has been described, but the manufacturing method is not particularly limited. In the following, referring to FIGS. 6 and 7, one example of a method for manufacturing an ink jet recording head according to the present embodiment will be described. An example will be described. 6 and 7 are longitudinal sectional views of the pressure generating chamber 12. FIG. First, as shown in Fig. 6 ('a), a silicon single crystal substrate wafer to be the flow channel forming substrate 10 is thermally oxidized in a diffusion furnace at about 110 ° C, and each surface is elastically deformed. After forming the film 50, as shown in FIG. 6 (b), an insulator film 55 made of zirconia or the like is formed on the elastic film 50. Next, as shown in FIG. 6 (c), for example, a lower electrode film 60 made of, for example, platinum and iridium is formed on the entire surface of the insulator film 55, and then patterned into a predetermined shape. Next, as shown in FIG. 6 (d), a piezoelectric layer 70 made of, for example, lead zirconate titanate (PZT) and an upper electrode film 80 made of, for example, iridium are sequentially laminated. Are simultaneously patterned to form a piezoelectric element 300.

Next, as shown in FIG. 7 (a), a lead electrode 90 made of, for example, gold (Au) is formed over the entire surface of the flow path forming substrate 10 and each piezoelectric element 300 is formed. Putter Jung every time. The above is the film forming process. Next, as shown in FIG. 7 (b), an inorganic insulating material, in this embodiment, is patterned into a predetermined shape to form the insulating film 2 0 0 consisting Sani匕aluminum (A l ₂ 0 ₃₎ . That is, the insulating film 200 is formed on the entire surface of the flow path forming substrate 10, and then the connecting portion 60 a of the lower electrode film 60 and the connecting portion 90 a of the lead electrode 90 are formed. The insulating film 200 in the opposing region is removed. Note that, in the present embodiment, in addition to the regions facing the connection portions 60 a and 90 a, the layers other than the layers constituting the piezoelectric element 300, the leads, and the pattern regions of the electrodes 90 are also removed. . Of course, in the insulating film 200, only the region facing the connecting portions 60a and 90a may be removed. In any case, the insulating film 200 constitutes the piezoelectric element 300 except for the connecting portion 60a of the lower electrode film 60 and the connecting portion 90a of the lead electrode 90. What is necessary is just to form so that each layer and the pattern area of the lead electrode 90 may be covered. The method for removing the insulating film 200 is not particularly limited. For example, it is preferable to use dry etching such as ion milling. As a result, the insulating film 200 can be selectively and satisfactorily removed.

Next, as shown in FIG. 7 (c), the piezoelectric element holding portion 31, the reservoir portion 32, etc. are formed in advance on the piezoelectric element 300 side of the flow path forming substrate 10 via an adhesive. Then, the reservoir forming substrate 30 is joined. It should be noted that such a reservoir forming substrate 30 will be described later. When forming the pressure generating chambers 12 and the like by anisotropically etching the flow path forming substrate 10 in the process described above, it also has a role of protecting each piezoelectric element 300 from an alkaline solution. The silicon single crystal substrate (flow path forming substrate 100) is anisotropically etched with the alkali solution thus formed to form the pressure generating chamber 12, the communication section 13, the ink supply path 14, and the communication path 100. Specifically, as shown in FIG. 7 (d), after a mask pattern 51 is formed on the surface of the flow path forming substrate 10 opposite to the bonding surface with the reservoir forming substrate 30, the mask pattern 51 is formed. The pressure generating chamber 12, the communication section 13, the ink supply path 14, and the communication path 100 are formed by anisotropically etching the flow path forming substrate 10 via the mask pattern 51. When performing the anisotropic etching, the surface of the reservoir forming substrate 30 is sealed with a protective film or the like. At this time, the reservoir 110 is formed by breaking the elastic film 50 and the insulator film 55 at the boundary between the reservoir portion 32 and the communication portion 13. As described above, in the present embodiment, since the ink supply path 14 and the like can be provided so as to penetrate in the thickness direction of the flow path forming substrate 10, if the mask pattern 51 is patterned with high precision, the ink supply path The path 14 and the communication path 100 can be formed with high accuracy. Therefore, stable ink ejection characteristics can be obtained.

Next, a nozzle plate 20 having a nozzle opening 21 formed on the surface of the flow path forming substrate 10 opposite to the reservoir forming substrate 30 is joined. After that, the compliance substrate 40 is bonded on the reservoir forming substrate 30, and the driving IC is mounted on the reservoir forming substrate 30, and the connection portion between the lower electrode film 60 and each lead electrode 90 is formed. Each of the piezoelectric elements 300 and the drive IC is electrically connected by connecting 600 a and 90 a to the drive IC by connection wiring composed of bonding wires. After the drive IC is mounted on the reservoir forming substrate 30 in this manner, the substrates such as the flow path forming substrate 10 and the reservoir forming substrate 30 are divided into chip sizes, as shown in FIG. Such an ink jet recording head according to the present embodiment is described.

(Other embodiments)

As described above, the embodiments of the present invention have been described, but of course, the present invention is not limited to the above embodiments. For example, in the above-described embodiment, the flow path is narrowed in the width direction. Thus, the ink supply path 14 is formed, but the invention is not limited thereto. The ink supply path may be formed by narrowing the flow path in the thickness direction of the flow path forming substrate. In this case, the ink supply path is formed by, for example, performing anisotropic etching (/, one fetching) on the flow path forming substrate in the thickness direction.

In the above-described embodiment, the piezoelectric element 300 is formed in the piezoelectric element holding portion 31 of the reservoir forming substrate 30. However, the present invention is not limited to this, and the piezoelectric element holding portion 31 may not be provided. . Even in this case, since the surfaces of the piezoelectric element 300 and the lead electrode 90 are covered with the insulating film 200 made of an inorganic insulating material, the piezoelectric layer 70 caused by moisture (humidity) is formed. Blasting is reliably prevented.

Further, in the above-described embodiment, the piezoelectric element 300 is covered with the insulating film 200. However, the present invention is not limited to this. The piezoelectric element may not be covered with the insulating film. One end of the reservoir forming substrate 30 is communicated with the piezoelectric element holding portion 31 and the other end is provided with an air opening hole 31 a that is open to the atmosphere, and the piezoelectric element holding portion 31 is opened to the atmosphere. However, the present invention is not limited to this, and the piezoelectric element holding portion may be sealed without providing the air opening hole. In this case, destruction of the piezoelectric element due to moisture (moisture) from the open-to-air hole is reliably prevented.

Further, in the above-described embodiment, a thin-film ink jet recording head manufactured by applying a film forming and lithography process has been described as an example. However, the present invention is not limited to this. The present invention can also be applied to a thick-film ink jet recording head formed by a method such as sticking.

Further, the ink jet recording head of each of the embodiments constitutes a part of a recording head having an ink flow path communicating with an ink cartridge or the like, and is mounted on an ink jet recording apparatus. FIG. 8 is a schematic view showing an example of the ink jet recording apparatus. As shown in FIG. 8, the recording heads 1A and 1B having ink jet recording heads are provided with detachable cartridges 2A and 2B constituting an ink supply means. The carriage 3 on which 1 A and 1 B 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. This record header 1A and 1B For example, it is assumed that a black ink composition and a color ink composition are respectively discharged.

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 heads 1A and 1B are mounted moves along the carriage shaft 5. Moved. On the other hand, the apparatus body 4 is provided with a platen 8 along a carriage axis 5, and a recording sheet S, which is a recording medium such as paper fed by a paper feed roller (not shown), is conveyed on the platen 8. It has become so.

In the above-described embodiment, an ink jet recording head and an ink jet recording apparatus which eject ink as a liquid ejecting head are described as an example. However, the present invention is widely applied to a liquid ejecting head. It is intended for liquid ejecting apparatuses in general. Examples of liquid ejecting heads include recording heads used in image recording devices such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (surface emitting displays). And the like, and an electrode material injection head used for forming an electrode, and a biological organic material injection head used for manufacturing a biochip.

Claims

The scope of the claims

1. A flow path forming substrate in which a plurality of pressure generating chambers communicating with the nozzle openings are arranged in parallel, and a piezoelectric element including a lower electrode, a piezoelectric layer, and an upper electrode provided on the flow path forming substrate via a diaphragm. And a reservoir forming substrate provided with a reservoir part which is joined to the surface of the flow path forming substrate on the side of the piezoelectric element and constitutes a part of a reservoir which is a common liquid chamber of each pressure generating chamber. And

The reservoir includes the reservoir portion and a communication portion provided in the flow path forming substrate, and partition walls on both sides in the width direction of the pressure generation chamber extend to near the end of the reservoir portion on the pressure generation chamber side. The liquid supply passage communicating with the pressure generating chamber and having a width smaller than the width of the pressure generating chamber, the liquid supply passage communicating with the liquid supply passage and the communication portion, and the liquid supply passage having a width smaller than the width of the liquid supply passage. A liquid jet head, wherein a communication passage having a large width is provided for each of the pressure generating chambers by the partition wall. 2. The width of the communication passage according to claim 1, _{W l} and the liquid jet head relation between the width w ₂ of the pressure generating chambers and satisfies the _{W l ≥w} _2.

3. In the range 1 or 2 according to the liquid jet head relationship between the width _{W l} and the width w ₃ of the liquid supply path of the communication passage and satisfies the _{W l} ≥ 2 X w _3.

4. The liquid jet head according to any one of claims 1 to 3, wherein a length of the different passage is equal to or greater than a thickness of the flow passage forming substrate.

5. The liquid ejecting apparatus according to any one of claims 1 to 4, wherein a distance between an end of the partition on the reservoir side and the reservoir is shorter than a thickness of the flow path forming substrate. Good.

6. The liquid jet head according to any one of claims 1 to 5, wherein the piezoelectric element is covered with an insulating film made of an inorganic insulating material.

7. In the range 6, wherein said insulating film head to the liquid jet, characterized in that it consists of A l ₂ 0 _3.

8. In any one of claims 1 to 7, the reservoir forming substrate can secure a space in a region facing the piezoelectric element so as not to hinder the movement of the piezoelectric element. A liquid ejecting device, wherein a region between the piezoelectric element holding portion and the reservoir portion of the reservoir forming substrate is a joint portion with the flow path forming substrate. Head.

9. The liquid jet head according to claim 8, wherein an end of the partition wall on the reservoir side is located in a region facing the joining portion.

10. The liquid jet head according to claim 8, wherein the length of the bonding portion is 200 μπι or more.

11. The liquid spray according to any one of claims 8 to 10, characterized in that one end is connected to the piezoelectric element holding portion and the other end is provided with an air opening hole that is open to the atmosphere. Head.

12. The liquid jet head according to any one of claims 1 to 11, wherein the thickness of the passage forming substrate is 100 μm or less.

13. The liquid projection head according to any one of claims 1 to 12, wherein the pressure generation chamber is formed on a silicon single crystal substrate by anisotropic etching.

14. A liquid ejecting apparatus comprising the liquid ejecting head according to any one of claims 1 to 13.