JP2003080697A - Ink-jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem wherein, in an ink-jet head, discharging efficiency is decreased by an undesired deformation in a region where a manifold space exists on the upper side among channel walls. SOLUTION: The ink-jet head is provided with a base member 1 in which a plurality of channel grooves 4 are formed so as to be separated by channel walls 3 containing piezoelectric materials, and a cover member 2 arranged by being brought into contact with the base member 1 so as to cover the channel grooves 4. The face of the side of the cover member 2 facing to the base member 1 contains a region A for making the channel grooves 4 to be rooms by being brought into contact with the top face of the channel walls 3, and a region B being recessed parts so as to be separated from the top faces of the channel walls 3. Projected parts 23 are arranged in the region B of the cover member 2, and the apexes of the projected parts 23 and the top faces of the channel walls 3 are bonded together.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet head used for a printer or the like. More specifically, the ink stored in an ink chamber defined by a wall including a piezoelectric member is ejected by applying a voltage to the piezoelectric member to deform the ink and causing pressure vibration in the ink chamber. The present invention relates to an inkjet head.

[0002]

2. Description of the Related Art In recent years, non-impact printers such as ink jet systems, which are easy to cope with colorization and multi-gradation, have rapidly spread in place of impact printers in printers. As an ink jet head used as an ink ejecting device for this purpose, a drop-on-demand type that ejects only ink droplets necessary for printing has been particularly noticed because of its good ejection efficiency and easy cost reduction. There is. As the drop-on-demand type, the Kyser method and the thermal jet method are mainly used.

However, the Kaiser system has a drawback that it is difficult to miniaturize and is not suitable for high density. Further, although the thermal jet method is suitable for increasing the density, it is a method in which ink is heated by a heater to generate bubbles in the ink and the energy of the bubbles is used to eject the ink. However, there is a problem that the heat resistance of the ink is required, it is difficult to extend the life of the heater, and the energy efficiency is low, so that the power consumption becomes large.

In order to solve the drawbacks of each of the above methods, an ink jet method utilizing the shear mode of a piezoelectric material has been disclosed. In this method, an electric field is generated in a direction orthogonal to the polarization direction of the piezoelectric material by using electrodes formed on both sides of an ink channel wall made of a piezoelectric material (hereinafter, referred to as “channel wall”), The channel wall is deformed in the share mode, and the pressure wave fluctuation generated at that time is used to eject ink droplets, which is suitable for high density nozzles, low power consumption, and high driving frequency.

(First Structure) With reference to FIGS. 12 and 13, a first structure of an ink jet head using such a share mode will be described. 13 is the same as FIG.
It is sectional drawing which cut | disconnected along the channel groove 4 in the state which assembled the inkjet head 2 of FIG. This inkjet head includes a base member 1 in which a plurality of channel grooves 4 are formed in a piezoelectric body that is vertically polarized in FIG. 12, and a cover member 2 in which an ink supply port 21 and a common ink chamber 22 are formed. An ink channel is formed by laminating the nozzle plate 9 having the nozzle holes 10 formed therein. “Ink channel” means channel groove 4
The part of the pressure chamber formed by utilizing the space inside. An electrode 5 for applying a voltage is provided on the channel wall 3.
Are formed only in the upper half.

The rear end portion of the ink channel is processed into an R shape corresponding to the diameter of a dicing blade used during groove processing, and the shallow groove portion 6 as an electrode lead-out portion for energization with the outside is also dicing. It is processed by a blade. The electrode formed in the shallow groove portion 6 is connected to the external electrode 8 provided on the flexible substrate, for example, at the rear end portion of the shallow groove portion by a bonding wire 7.

(Second Structure) On the other hand, as a second structure of the ink jet head, a structure without an R-shaped portion or a shallow groove portion has been proposed. The second structure of the conventional inkjet head will be described with reference to FIGS. 14 and 15. Compared with the ink jet head having the first structure, the connection method from the electrode 5 to the external electrode 8 is largely different. As shown in FIG. 14, the conductive resin 26 is embedded in the channel groove 4 at the rear end of the base member 1 (the end on the opposite side to which the nozzle plate 9 is attached). The electrodes 5 on both sides of one channel groove 4 are electrically connected by the conductive resin 26 so as to have the same potential. The conductive resin 26 of one channel groove 4 and the conductive resin 26 of the adjacent channel groove 4 are electrically separated from each other. Further, a flexible printed circuit board 11 having external electrodes 8 on its surface is attached to an end portion of the base member 1 so as to be perpendicular to the base member 1,
The conductive resins 26 are independently connected to the external electrodes 8. To connect the conductive resin 26 and the external electrode 8,
An anisotropic conductive film (ACF) is used.

In this ink jet head, unlike the ink jet head of the first structure, since the rear end of the channel groove 4 is sealed by the conductive resin 26, the ink is supplied to the ink channel of the base member 1. It is performed from the upper side in FIG. Therefore, the manifold space 2 formed by the manifold member 20
In addition to 4a, the cover member 2 also has a manifold space 24
b is provided. Therefore, the manifold space 2
The combined space of 4a and 24b serves as a common ink chamber. The ink supplied from the ink supply port 21 of the manifold member 20 enters the ink channel via the manifold spaces 24a and 24b.

(Deformation of Channel Wall) With reference to FIGS. 16 to 19, the deformation of the channel wall 3 in the shear mode in the ink jet head having these configurations will be described. 16 to 19 show cross sections of the ink channel in the area A. In the initial state, the channel wall 3 stands upright as shown in FIG. By applying a voltage to the electrodes 5 stretched on both left and right sides of the channel wall 3, an electric field perpendicular to the polarization direction is generated, and shear mode deformation (shear deformation) occurs. For example, a voltage is applied to the electrode 5 as shown in FIG. That is,
The positive constant voltage is applied for the first time T1, and the negative constant voltage is subsequently applied for the time T2. As a result, during the first time T1, as shown in the center of FIG. 18, the channel wall 3 is deformed into a V shape and acts on one ink channel so as to widen the cross-sectional area. . During the next time T2, an electric field in the opposite direction is generated, so that the channel wall 3 is formed as shown in FIG.
The channel chamber 4 is deformed so as to reduce its cross-sectional area. This change happens rapidly. In the inkjet head utilizing the shear mode deformation, pressure wave fluctuation is generated in the ink channel by performing such a series of voltage application at appropriate timing, and the nozzle hole 10 is formed.
More ink is ejected.

[0010]

In the shear mode deformation as described above, as shown in FIG. 16, a region where the upper end of the channel wall 3 is fixedly adhered to the cover member 2, that is, in FIG. 13 and FIG. It occurs in area A. But,
Also in the region B in FIGS. 13 and 15, the electrode 5 is formed on the channel wall 3, and applying the voltage to the electrode 5 in the region A includes applying the voltage to the region 5 as well as the region B. Channel wall 3 in area A
If a shear mode deformation is to be generated in the area B,
The channel wall 3 will also be deformed. However, since the upper end of the channel wall 3 is not adhesively fixed to the cover member 2 in the region B, the channel wall 3 is shaken at the upper end instead of being deformed into the V shape as in the region A. To be transformed. Therefore, for example, when the area A is deformed so as to widen the cross-sectional area of the ink channel as shown in FIG. 18, the area B is deformed as shown in FIG. To work. When the region A is deformed as shown in FIG. 19, the upper end of the channel wall 3 is swung outward in the region B and acts not only to narrow the cross-sectional area of the ink channel but to widen it. Moreover, since the upper end of the channel wall 3 is not fixed, only a flow of ink to the side is generated, and a pressure change is not so much generated.

On the other hand, in the region B (see FIGS. 13 and 15), since the upper end of the channel wall 3 is not fixed, the channel wall 3 is not deformed positively, but the region A is not formed. (See FIG. 13 and FIG. 15). Since the deformation of the channel wall 3 having the “<” shape propagates to the region B,
Even in the region B, the pressure wave fluctuates to some extent. But,
The pressure fluctuation occurring in the region B has a different propagation velocity because the volume of the space and the constraint condition of the channel wall 3 are different from those in the region A.

As a result, even if the same voltage is applied, the pressure wave fluctuations generated in the areas A and B are different, and the pressure wave fluctuations in the area B have an undesired effect on the pressure wave fluctuations in the area A. Exert. It also affects the supply of ink from the outside. Due to such a phenomenon, ink ejection becomes unstable. In particular, when the frequency for applying the voltage, that is, the drive frequency is increased, the fluctuation of the pressure wave in the region B becomes larger, and the ink ejection becomes more unstable.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet head which solves such a problem and is capable of stable ink ejection.

[0014]

In order to achieve the above object, an ink jet head according to the present invention comprises a base member having a plurality of channel grooves formed so as to be separated from a channel wall containing a piezoelectric material, and the above plurality of base members. A cover member arranged in contact with the base member so as to cover the channel groove, and a surface of the cover member facing the base member has a first region in contact with an upper surface of the channel wall, A second region that is a recess so as to be separated from the upper surface of the channel wall, and projects from the bottom of the recess so as to contact the upper surface of the channel wall in the second region of the cover member. Is arranged, and the tip of the projection is joined to the upper surface of the channel wall. By adopting this configuration,
Since the tip of the convex portion and the upper surface of the channel wall are joined together, the upper end of the channel wall is restrained even in the second region, so that the channel wall is undesirably deformed in the second region. It does not occur and can be efficiently transformed in the share mode.

In the above invention, preferably, the projections are arranged at the same pitch as the channel walls are arranged on the base member. By adopting this configuration, the shape of each ink channel can be made equal, and the ink ejection conditions in each ink channel can be made uniform.

In the above invention, preferably, the convex portions are arranged at the same pitch as that selected for every other one of the channel walls arranged on the base member. By adopting this configuration, it is possible to suppress the undesired deformation of each channel wall while securing a large volume of the concave portion of the second region forming a part of the common ink chamber. In the region, the ink can freely move between the ink channels adjacent to each other by two, so that the uniform supply of the ink to each channel groove can be performed more reliably.

In the above invention, preferably, the convex portion has a shape that becomes thinner from the root toward the tip. By adopting this configuration, since the convex portion has such a cross-sectional shape, the convex portion has high rigidity against external force. Therefore, in the second region, the tip of the channel wall is more firmly restrained by the convex portion, the channel wall can be efficiently deformed in the shear mode, and the ink ejection efficiency can be improved.

In the above invention, preferably, the convex portion intermittently contacts the upper surface of the channel wall along the longitudinal direction of the channel wall. By adopting this configuration, in the second region, there is a portion where the upper surface of the channel wall is joined to the convex portion of the cover member, so that the channel wall is restrained and undesired deformation can be suppressed, The share mode can be transformed efficiently. Further, since the convex portion is limited, it is possible to secure a large volume of the concave portion of the second region forming a part of the common ink chamber. Furthermore, in the recess of the second region,
Since the ink can be freely moved between different ink channels, it is possible to more reliably supply the ink to each channel groove uniformly.

In the above invention, preferably, the height of the convex portion viewed from the bottom of the concave portion is 60% or more and 200% of the height of the channel wall viewed from the bottom of the channel groove.
It is the following. By adopting this configuration, the influence of the pressure wave fluctuations generated in the second region on the pressure wave fluctuations generated in the first region is suppressed to a small level, and the convex portion for restraining the channel wall in the second region is adopted. It is possible to secure sufficient rigidity.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) (Structure) The structure of an inkjet head according to Embodiment 1 of the present invention will be described with reference to FIGS. As shown in FIG. 1, the structure is basically the same as that shown in FIGS. 14 and 15, but in this inkjet head, the convex portion 23 is provided in the manifold space 24b formed in the cover member 2. There is. The convex portion 23 is linearly provided in a position corresponding to the channel wall 3 on the base member 1 side in parallel, and as a result, the manifold space 2 is formed.
4b is divided into a plurality of elongated spaces.

Further, FIG. 2 shows a sectional view when the ink jet head is cut parallel to the longitudinal direction of the ink channel. As shown in FIG. 2, the inkjet head can be divided into a region A as a first region and a region B as a second region. Figure 3
FIG. 8 shows a sectional view of the inkjet head cut in the region B perpendicularly to the longitudinal direction of the ink channel. As shown in FIG. 3, the upper surface of the convex portion 23 and the upper surface of the channel wall 3 are adhesively fixed to each other. Therefore, as shown in FIG. 2, the ink supplied from the ink supply port 21 is separately supplied into the manifold space 24b, which is divided into an elongated shape from the manifold space 24a, and is further supplied to the channel groove 4.

(Manufacturing Method, etc.) Specific dimensions of each part of the ink jet head and a manufacturing method will be described below. The channel groove 4 has a depth of 300 μm, a width of 70 μm, and a pitch of 141 μm. The length of the area A is 1.1 mm, and the length of the area B is 2.5 mm. The protrusions 23 provided on the cover member 2 have a width of 71 μm, a pitch of 141 μm,
The length is 2.5 mm and the height is 400 μm. Since the convex portions 23 and the channel walls 3 are provided at the same pitch,
The shape of each ink channel in the region B can be the same. In this example, the width of the upper surface of the convex portion 23 and the width of the upper surface of the channel wall 3 are matched with each other, but it is not always necessary to match them.

The electrode 5 is formed by oblique vapor deposition using Al as a material and has a thickness of 1.0 μm.
Is. As the material of the electrode 5, in addition to Al, Cu, N
A conductive material such as i or Ti may be used.

The nozzle plate 9 is made of a polyimide film having a thickness of 90 μm, and the nozzle holes 10 are provided by excimer laser processing. As the nozzle plate 9, a polyethylene-based polymer resin film may be used instead of the polyimide film. Alternatively, the nozzle holes 10 may be punched in a metal plate such as a stainless plate.

In the ink jet head of this embodiment, an anisotropic conductive film (ACF) is used for connecting the external electrode 8 and the conductive resin 26.

In the ink jet head according to the present embodiment, the cover member 2 is a piezoelectric substrate that has not been subjected to polarization treatment, and is sandblasted.
The manifold space 24b and the convex portion 23 are formed. As the cover member 2, a ceramic substrate or the like may be used instead of the piezoelectric substrate that has not been polarized. In order to form the manifold space 24b and the convex portion 23, milling or molding may be used.

(Operation / Effect) In the ink jet head according to this embodiment, the manifold space 24b has the convex portion 2
Since the projections 23 and the channel walls 3 are separated by 3, and the channel walls 3 are adhesively fixed, each nozzle hole 10 has an independent ink channel. Since the convex portion 23 and the channel wall 3 are adhesively fixed to each other, the upper end of the channel wall 3 is restrained even in the region B, so that the conventional deformation as shown in FIG. Can be transformed in modes. As a result, ink can be ejected efficiently and the drive voltage can be reduced.

In the conventional ink jet heads shown in FIGS. 14 and 15, the ink ejection was performed by the pressure wave fluctuation generated in the area A.
The shorter the length of the region A, the higher the driving frequency. Further, the application timing of the voltage applied from the external electrode 8 to the electrode 5 for ejecting ink has an optimum value related to the length of the region A. From these viewpoints, in the conventional inkjet head,
The length of the area A is a very important factor.

In the ink jet head of this embodiment, unlike the conventional ink jet heads shown in FIGS. 14 and 15, even in the region B, since each ink channel is independent, some pressure wave fluctuation occurs. ,
Since the cross-sectional area of the ink channel in the area A is smaller than that in the area B, the area A in the entire ink channel is
The pressure wave fluctuations that occur at 2) become dominant. Therefore, the ejection of ink is substantially performed by the pressure wave fluctuation occurring in the area A as in the conventional case.

In the above example, the height of the convex portion 23 is 400 μm.
However, when the height of the convex portion 23 becomes smaller than 60% of the height of the channel wall 3, that is, 180 μm, which is 60% of 300 μm in this example, in the region B compared to the region A. The increase in the cross-sectional area becomes insufficient, and the degree of the influence of the pressure wave fluctuation occurring in the region B on the pressure wave fluctuation in the region A exceeds the allowable range. On the contrary, when the height of the convex portion 23 becomes smaller than 200% of the height of the channel wall 3, that is, 600 μm which is 200% of 300 μm in this example, the channel wall 3 of the base member 1 is restrained in the region B. Therefore, the rigidity of the convex portion 23 is insufficient, and the deformation of the channel wall 3 in the region B becomes close to that shown in FIG. 20, and the efficiency of the shear mode deformation becomes low. Therefore, the height of the convex portion 23 is preferably 60% or more and 200% or less of the height of the channel wall 3.

(Second Embodiment) (Structure) The structure of an ink jet head according to a second embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 4, the structure is basically the same as that described in the first embodiment, but in this ink jet head, the projection 23 in the manifold space 24b of the cover member 2 is formed on all the channel walls 3. It is not provided correspondingly, but is arranged corresponding to only every other selected one of the channel walls 3. Figure 5
FIG. 8 shows a cross-sectional view in the case of cutting in the region B perpendicular to the longitudinal direction of the ink channel. As shown in FIG. 5, the upper surfaces of the protrusions 23 are formed on every other selected channel wall 3.
The upper surface of each is fixed by adhesion.

(Operation / Effect) In this ink jet head, when ink is ejected from a certain ink channel, the channel groove 4 of the ink channel is formed.
Transform the channel walls on both sides of the same to share mode. Therefore, as shown in FIG. 5, even if the convex portions 23 are adhered and fixed only to every other channel wall 3, all the ink channels have channel walls whose one side is adhered and fixed to the convex portions 23. 3 and the conditions are the same in that the other side is the channel wall 3 that is not adhered and fixed to the convex portion 23, so that the method of ejecting ink is uniform. In any of the ink channels, one of the left and right channel walls 3 is constrained by being adhesively fixed to the convex portion 23, so that it is more efficient than when the upper ends of the channel walls 3 are not fixed on both sides. The share mode can be modified.

In this ink jet head, the number of the convex portions 23 can be reduced to about half of that in the first embodiment, so that the volume of the manifold space 24b can be increased. Therefore, the ink can be smoothly supplied from the manifold space 24a to the channel groove 4. In particular, the manifold space 24b
In the above, since the ink can be freely moved between the ink channels adjacent to each other by two, the uniform supply of the ink to each channel groove 4 can be performed more reliably.

(Third Embodiment) (Structure) The structure of an ink jet head according to a third embodiment of the present invention will be described with reference to FIGS. 6 and 7. As shown in FIG. 6, the structure is basically the same as that described in the second embodiment, but the shape of the convex portion 23 is different. In this inkjet head, the protrusions 23 in the manifold space 24b of the cover member 2 do not have the same width from the root to the tip, but the width becomes smaller toward the tip. FIG. 7 shows a cross-sectional view of the region B when cut perpendicularly to the longitudinal direction of the ink channel. The protrusion 23 has a trapezoidal cross-sectional shape, as shown in FIG. 7.

(Manufacturing Method) The convex portion 2 in the present embodiment
The shape of 3 can be formed by sandblasting as in the first embodiment. About this processing
This will be described with reference to FIGS. 8 and 9. As shown in FIG. 8, in the sandblasting process, the dry resist film 3
The cross-sectional shape of the 0 mask is a trapezoid. When sandblasting is performed in this state, the cover member 2 is gradually scraped off from the surface, but the dry resist film 30 is also gradually scraped off, and the masked area becomes narrow.
As the masked area becomes narrower, the cover member 2 will be removed even in the previously masked area. As a result, the convex portion 23 having a trapezoidal cross-sectional shape is formed on the cover member 2. FIG. 9 shows a state in which the convex portion 23 is being formed. The sandblasting process is continued until the dry resist film 30 is almost completely removed, so that the projections 23 having the shapes shown in FIGS. 6 and 7 are obtained. The dry resist film 30
The initial shape of can be arbitrarily controlled by the exposure amount, development time, heat treatment conditions after mask formation, and the like.

(Operation / Effect) In addition to the same effects as the second embodiment, the ink jet head of the present embodiment has
The following effects can be obtained. Since the convex portion 23 has such a cross-sectional shape, the convex portion 23 has high rigidity against an external force in the left-right direction in FIG. 7. Therefore, in the region B, the tip end of the channel wall 3 is more firmly restrained by the convex portion 23, and it is possible to prevent the deformation of the channel wall 3 from being mixed with a vibration mode other than the desired shear mode deformation. As a result, the channel wall 3 can be efficiently deformed in the shear mode, and the ink ejection efficiency can be improved.

In the above-mentioned example, the cover member 2 has the convex portion 23.
The width of the tip is 71 μm and the width of the root is 130 μm. The width of the tip of the convex portion 23 may be another value as long as it can be adhesively fixed to the upper surface of the channel wall 3. The width of the root may be larger, and for example, as shown by the broken line in FIG. 7, the valley-shaped portion of the cover member 2 sandwiched between the convex portions 23 may be V-shaped. In this case, the opening of the manifold space 24b viewed from the side of the manifold space 24a has a triangular shape.

In the present embodiment, as in the second embodiment, the convex portion 23 is adhered and fixed only to every other selected channel wall 3.
As in the first embodiment, the projections 2 are formed on all the channel walls 3.
In the structure in which 3 is adhered and fixed, the cross-sectional shape of the convex portion 23 may be trapezoidal.

(Fourth Embodiment) (Structure) With reference to FIGS. 10 and 11, the structure of an ink jet head according to a fourth embodiment of the present invention will be described. As shown in FIG. 10, the structure is basically the same as that described in the first embodiment, but the shape of the convex portion 23 is different. In this inkjet head, the convex portion 23 in the manifold space 24b of the cover member 2 does not extend over the entire length of the region B as viewed in the ink channel longitudinal direction, but only in a limited portion of the region B. It is protruding. FIG. 11 shows a sectional view of the ink jet head cut in parallel with the longitudinal direction of the ink channel. As a result of the protrusions 23 protruding in only a limited part of the area B, as shown in FIG. 11, in the areas C1 and C2 of the area B, the manifold spaces 24b of the respective ink channels communicate with each other. .

(Operation / Effect) In this ink jet head, in the region B, there is a portion where the upper surface of the channel wall 3 is adhesively fixed to the convex portion 23 of the cover member 2.
The deformation of the channel wall 3 is restrained to some extent, and the channel wall 3 can suppress the undesired deformation as shown in FIG. 20 and can be efficiently compared with the conventional ink jet head shown in FIGS. The share mode can be modified.

The manifold space 24b has regions C1 and C2.
, The volume of the manifold space 24b can be increased. Therefore, the ink can be smoothly supplied from the manifold space 24a to the channel groove 4. Especially, the manifold space 2
In 4b, the ink can be freely moved between different ink channels, so that the uniform supply of ink to each channel groove 4 can be performed more reliably.

In this embodiment, the length of the region C1 is 0.5 mm, the length of the region C2 is 0.7 mm, and the length of the convex portion 23 to be fixedly bonded to the channel wall 3 is 1.3 m.
Although the length is m, these lengths are not limited to these values and may be appropriately selected.

Further, in the present embodiment, the convex portion 23 of the cover member 2 is only one portion in the region B as seen in the longitudinal direction of the ink channel as shown in FIG.
The protrusions 23 may be provided at two or more places in the region B when viewed in the longitudinal direction of the ink channel. That is, the convex portion 23
Along the longitudinal direction of the channel wall 3
It suffices if it is intermittently in contact with the upper surface of. In addition, the convex portion 23
The shape may be trapezoidal in cross section as described in the third embodiment.

While the first to fourth embodiments have described the case where the present invention is applied based on the conventional inkjet head having the second structure, the present invention is based on the conventional first structure. It is also applicable to the inkjet head.

The above-described embodiment disclosed this time is illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the scope of the claims, and includes meaning equivalent to the scope of the claims and all modifications within the scope.

[0046]

According to the present invention, since the tip of the convex portion and the upper surface of the channel wall are joined, the upper end of the channel wall is restrained even in the region B as the second region. Therefore, it is possible to prevent the channel wall from being undesirably deformed in the region B as the second region. As a result, the deformation can be efficiently performed in the share mode, and the driving voltage can be reduced.

[Brief description of drawings]

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

FIG. 2 is a vertical cross-sectional view of the inkjet head according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view of the inkjet head according to the first embodiment of the present invention.

FIG. 4 is an exploded perspective view of an inkjet head according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view of an inkjet head according to a second embodiment of the present invention.

FIG. 6 is an exploded perspective view of an inkjet head according to a third embodiment of the present invention.

FIG. 7 is a cross-sectional view of an inkjet head according to a third embodiment of the present invention.

FIG. 8 is a first explanatory diagram of a step of forming a convex portion according to the third embodiment of the present invention.

FIG. 9 is a second explanatory view of the step of forming the convex portion according to the third embodiment of the present invention.

FIG. 10 is an exploded perspective view of an inkjet head according to a fourth embodiment of the present invention.

FIG. 11 is a cross-sectional view of an inkjet head according to a fourth embodiment of the present invention.

FIG. 12 is an exploded perspective view of an inkjet head having a first structure based on a conventional technique.

FIG. 13 is a vertical cross-sectional view of an inkjet head having a first structure based on a conventional technique.

FIG. 14 is an exploded perspective view of an inkjet head having a second structure based on a conventional technique.

FIG. 15 is a vertical cross-sectional view of an inkjet head having a second structure according to the related art.

FIG. 16 is a cross-sectional view of an initial state in a region A of an ink channel.

FIG. 17 is a graph showing a voltage applied to an electrode of an ink channel.

FIG. 18 is a sectional view showing a first deformed state in a region A of the ink channel.

FIG. 19 is a cross-sectional view showing a second deformed state in a region A of the ink channel.

FIG. 20 is a cross-sectional view showing a deformed state in a region B of an ink channel of an inkjet head according to the related art.

[Explanation of symbols]

1 base member, 2 cover member, 3 channel wall,
4 channel grooves, 5 electrodes, 6 shallow groove parts, 7 bonding wires, 8 external electrodes, 9 nozzle plates, 10 nozzle holes, 11 flexible printed boards, 20 manifold members, 21 ink supply ports, 23 convex parts, 24
a, 24b Manifold space, 26 conductive resin, 30
Dry resist film.

Claims (6)

[Claims] 1. A base member having a plurality of channel grooves formed so as to be separated from a channel wall containing a piezoelectric material, and a cover member disposed in contact with the base member so as to cover the plurality of channel grooves. A surface of the cover member on the side facing the base member is a first region in contact with an upper surface of the channel wall,
A second region that is a recess so as to be separated from the upper surface of the channel wall, and in the second region of the cover member, protrudes from the bottom of the recess so as to contact the upper surface of the channel wall. An ink jet head in which a convex portion to be formed is arranged, and a tip of the convex portion is joined to an upper surface of the channel wall. 2. The inkjet head according to claim 1, wherein the convex portions are arranged at the same pitch as the channel walls are arranged on the base member. 3. The ink jet head according to claim 1, wherein the convex portions are arranged at the same pitch as that selected for every other one of the channel walls arranged on the base member. 4. The inkjet head according to claim 1, wherein the convex portion has a shape that becomes narrower from the root toward the tip. 5. The inkjet head according to claim 1, wherein the convex portion intermittently abuts an upper surface of the channel wall along a longitudinal direction of the channel wall. 6. The height of the protrusion as viewed from the bottom of the recess is 60% or more and 200% or less of the height of the channel wall viewed from the bottom of the channel groove. The inkjet head according to any one of 1.