JP2003025568A - Liquid drop ejection head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid drop ejection head for ejecting a liquid drop at a low voltage. SOLUTION: The liquid drop ejection head comprises a pressure chamber (2) for pressurizing a liquid (11) provided with an opening (1a) for ejecting the liquid (11) in the form of a liquid drop (12), a diaphragm (6) placed on the pressure chamber (2), and a displacement generating element (5) mounted on the diaphragm (6). The displacement generating element (5) and the diaphragm (6) are bonded partially. Inner pressure of the pressure chamber (2) is varied by deflection of the diaphragm (6) caused by a displacement generated by the displacement generating element (5). The liquid drop (12) is ejected from the opening (1a) based on the pressure variation in the pressure chamber (2).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a droplet discharge head, and more particularly to a droplet discharge head that pressurizes a liquid and discharges droplets.

[0002]

2. Description of the Related Art In recent years, an ink jet recording apparatus using an ink jet recording head, which is a practical example of a liquid droplet ejection head, is capable of high-quality printing, and is widely used as an image output apparatus with the spread of personal computers. It has come to be used. There is a demand for further speeding up, downsizing, and cost reduction of such an ink jet recording apparatus.

Generally, the ink jet recording head is
It has a nozzle that ejects ink, a pressure chamber that communicates with the nozzle and pressurizes the ink, and an ink pool that communicates with the pressure chamber through the ink supply port. One surface of the pressure chamber is composed of a vibration plate to which a piezoelectric element is joined.

An ink jet recording head using a piezoelectric element is shown in FIGS. 55 and 56. FIG. 55 is a sectional view showing a conventional inkjet recording head. FIG. 56 is a cross-sectional view showing an ink droplet ejection operation of a conventional inkjet recording head.

As shown in FIG. 55, a conventional ink jet recording head 100 includes a nozzle plate 109 and a nozzle plate 109.
A plate 108, a diaphragm 106, an adhesive layer 107,
And a piezoelectric element 105.

On the nozzle plate 109, the plate 1
08 is provided. The diaphragm 106 is provided on the plate 108. The plate 108, the nozzle plate 109, and the vibrating plate 106 form a pressure chamber 102 for containing ink, and the pressure chamber 102 contains ink 111.
Is filled. Further, the plate 108, the nozzle plate 109, and the vibration plate 106 form an ink pool 104 for containing ink, and the ink pool 104 is filled with ink 113.

The plate 108 has an ink pool 104.
A supply port 103 is formed in communication with the pressure chamber 102 for replenishing / supplying the ink 113 contained in the ink pool 104 to the pressure chamber 102 as the ink 111. The nozzle plate 109 is formed with a nozzle 101 that communicates with the pressure chamber 102 and discharges the ink 111 as an ink droplet.

The piezoelectric element 105 is polarized in advance by a polarization process. This pre-polarized piezoelectric element 105
Deforms based on the applied voltage.

Here, the piezoelectric material forming the piezoelectric element is
Normally, piezoelectricity is not shown in the initial state (virgin material).
When an electric field having a predetermined value or more is externally applied (polarization treatment), the piezoelectric element exhibits a piezoelectric effect according to a minute electric field from the outside. The process of externally applying an electric field having a predetermined value or more is called a polarization process.

An adhesive layer 107 is provided on the diaphragm 106. The piezoelectric element 105 is bonded onto the adhesive layer 107. The piezoelectric element 105 is bonded to the diaphragm 106 by an adhesive layer 107 over the entire lower surface.

In the conventional example having such a structure, when the piezoelectric element 105 is polarized in the thickness direction and a voltage is applied to the piezoelectric element 105 in the same direction as the polarization direction, the piezoelectric element 105 is formed as shown in FIG. Reference numeral 105 compresses the piezoelectric element 105 bonding surface of the vibrating plate 106 in the in-plane direction in an attempt to shrink in the direction perpendicular to the voltage application direction (direction of arrows c and d in FIG. 56).
As a result, the piezoelectric element 105 and the diaphragm 106 are flexibly deformed.

As shown in FIG. 56, in the conventional ink jet recording head 100, when the piezoelectric element 105 moves / drives (deflects) in response to the application of voltage, the piezoelectric element 105 and the diaphragm 106 are Since it is bonded to the adhesive layer 107, it bends so as to have the same curvature. Pressure chamber 10
In No. 2, the internal pressure changes (volume displacement) based on the movement of the piezoelectric element 105 (deflection of the vibrating plate 106), and the ink droplet 112 is ejected from the nozzle 101 based on the change in pressure of the pressure chamber 102. It

[0013]

Generally, in the case of a plurality of pressure chambers, the ink jet recording head requires high density arrangement of the pressure chambers for size reduction.

In order to increase the density, it is necessary to reduce the occupied area of the pressure chamber. Generally, when the occupied area of the pressure chamber is reduced, the volume displacement of the pressure chamber due to the driving of the piezoelectric element at the time of ink ejection. Since it becomes small, sufficient pressure cannot be applied. In the inkjet recording head 100, in order to increase the density of the pressure chambers 102,
It is necessary to make the head structure so that the pressure chamber 102 occupies as small an area as possible and the required volume displacement is as large as possible.

Therefore, the volume displacement of the pressure chamber 102 for pressurizing the ink 111 is significantly improved without increasing the occupied area of the pressure chamber 102, and the density of the pressure chamber 102 can be increased. Is desired.

Further, as shown in FIG. 56, in the ink jet recording head 100, since the piezoelectric element 105 is bonded to the vibration plate 106 by the adhesive layer 107 over the entire lower surface, the ink is ejected (during driving). , Piezoelectric element 10
5 flexibly deforms according to the application of a voltage so as to have the same curvature as that of the diaphragm 106. Therefore, the energy generated in the piezoelectric element 105 in response to the application of the voltage is
The piezoelectric element 1 is not only used for bending the 6
05 is also consumed by bending itself, and the volume displacement efficiency with respect to the input voltage is poor.

Further, in the ink jet recording head 100, it is possible to increase the applied voltage to increase the volume displacement of the diaphragm 106 to some extent, but there is a problem of safety and cost increase due to the high voltage. In addition, the piezoelectric element 10
Since the strain generated by 5 also saturates in the presence of the strain, the volume displacement does not increase so much even if the voltage is increased abruptly.

Therefore, the piezoelectric element 105 can be operated at a low voltage without increasing the energy generated in the piezoelectric element 105.
The pressure chamber 10 to drive the ink and pressurize the ink 111.
It is desired to reduce the power consumption and the voltage of the head by significantly improving the volume displacement of No. 2.

Further, it is desired that it can be applied to liquids other than ink.

An object of the present invention is to provide a droplet discharge head which can discharge droplets at a low voltage.

Another object of the present invention is to provide a droplet discharge head which greatly improves volume displacement of a pressure chamber for pressurizing a liquid.

Still another object of the present invention is to provide a droplet discharge head which enables the density and size of the pressure chambers to be increased.

Still another object of the present invention is to provide a droplet discharge head which can reduce the power consumption and the voltage of the head.

[0024]

[Means for Solving the Problems] Means for solving the problems will be described below with reference to the numbers and symbols used in the embodiments of the present invention. These numbers and signs are added to clarify the correspondence between the description in [Claims] and the description in [Embodiment of the Invention], but in [Claims] It should not be used to interpret the technical scope of the described invention.

The liquid droplet ejection head of the present invention comprises a liquid (11)
A pressure chamber (2) for pressurizing the liquid, and an opening (1a) for discharging the liquid (11) as a droplet (12) into the pressure chamber (2).
And a vibration plate (6, 6 provided on the pressure chamber (2).
26, 36, 46, 56, 66) and the diaphragm (6, 2)
6, 36, 46, 56, 66) and the displacement generating elements (5, 25, 35, 45, 55, 56) provided on the same. Displacement generating elements (5, 25, 35, 45, 55, 6
5) and the diaphragms (6, 26, 36, 46, 56, 66) are partially joined. The pressure chamber (2) includes diaphragms (6, 26, 36, 4) generated based on the displacement generated by the displacement generating elements (5, 25, 35, 45, 55, 65).
6, 56, 66) causes the internal pressure to change. The droplet (12) is ejected from the opening (1a) based on the change in the pressure of the pressure chamber (2).

The droplet discharge head of the present invention further comprises a displacement generating element (5, 25, 35, 55) and a vibrating plate (6, 26,
36, 56) and an adhesive part (7, 27,
37, 57).

The shape of the displacement generating element (5) is a circle. The adhesive part (7) is provided along the circumference of the circle.

The shape of the displacement generating element (5) is a square.
The adhesive part (7) is provided along at least two sides of the four sides of the square. Examples of the square include a square and a rectangle.

A groove (26a) is formed on the surface of the diaphragm (26).
Are formed. The adhesive part (27) is provided in the groove (26a). A displacement generating element (25) is provided on the adhesive portion (27) and the diaphragm (26).

The shape of the displacement generating element (25) is a circle.
The adhesive portion (27) and the groove (26a) are provided along the circumference of the circle.

The shape of the displacement generating element (25) is a square. The adhesive part (27) and the groove (26a) are provided along at least two sides of the four sides of the square. Examples of the square include a square and a rectangle.

On the surface of the vibrating plate (36), the protrusion (36
a) has been formed. The adhesive portion (37) has a protrusion (3
6a). A displacement generating element (35) is provided on the adhesive portion (37).

The displacement generating element (55) has a protrusion (55
e) has been formed. A protrusion (55e) is provided on the adhesive portion (57).

The shape of the displacement generating element (35, 55) is a circle. Adhesives (37, 57) and protrusions (36a, 55)
e) is provided along the circumference of the circle.

The displacement generating elements (35, 55) have a square shape. Adhesives (37, 57) and protrusions (36a, 55)
e) is provided along at least two sides of the four sides of the square. Examples of the square include a square and a rectangle.

On the surface of the vibrating plate (46), the protrusions (46
a) has been formed. The droplet discharge head of the present invention further includes an adhesive portion (47) for joining the displacement generating element (45) and the protrusion (46a).

The displacement generating element (65) has a protrusion (65
e) has been formed. The droplet discharge head of the present invention further includes an adhesive portion (67) for joining the protrusion (65e) and the vibration plate (66).

The shape of the displacement generating element (45, 65) is a circle. The protrusions (46a, 65e) are provided along the circumference of the circle.

The shape of the displacement generating element (45, 65) is a square. The protrusions (46a, 65e) are provided along at least two sides of the four sides of the square. Examples of the square include a square and a rectangle.

The shape of the pressure chamber (2) is a truncated pyramid.
An opening is provided on the first surface (2a) of the truncated pyramid. The second surface (2b) larger than the first surface (2a) of the truncated pyramid is
The diaphragm (6, 26, 36, 46, 56, 66) is formed. Displacement generating elements (5, 25, 35, 4
5, 55, 65) are displacement generating elements (5, 25, 35,
It is provided above the pressure chamber (2) so that the displacement generated by (45, 55, 65) is transmitted to the second surface (2b).

The shape of the pressure chamber (2) is a truncated cone. An opening (1a) is provided on the first surface (2a) of the truncated cone. A second surface (2b) that is larger than the first surface (2a) of the truncated cone
Are formed by diaphragms (6, 26, 36, 46, 56, 66). Displacement generating elements (5, 25, 35,
45, 55, 65) are displacement generating elements (5, 25, 3)
5, 45, 55, 65) is generated by the displacement of the second surface (2
It is provided above the pressure chamber (2) so as to be transmitted to b).

The droplet discharge head of the present invention is further stored in the pool (4), which communicates with the pool (4) containing the liquid (13), the pool (4) and the pressure chamber (2). Supply port (3) for supplying the liquid (13) to the pressure chamber (2)
It has and.

The droplet discharge head of the present invention is used in an ink jet recording apparatus. Further, the droplet discharge head of the present invention is used in an organic EL display film forming apparatus. Also,
The droplet discharge head of the present invention is used in a solder bump forming apparatus.

[0044]

BEST MODE FOR CARRYING OUT THE INVENTION A droplet discharge head according to the present invention is
It is used in ink jet recording devices, organic EL display film forming devices, solder bump forming devices, and the like. As an embodiment of a droplet discharge head according to the present invention, an inkjet recording head used in an inkjet recording apparatus will be described as an example with reference to the accompanying drawings. The ink jet recording head according to the present embodiment employs a method of ejecting ink droplets onto recording paper by pressing a pressure chamber containing ink with a piezoelectric element.

(First Embodiment) An ink jet recording head 10 according to the first embodiment will be described with reference to FIG. FIG. 1 is a sectional view showing an inkjet recording head according to the first embodiment.

As shown in FIG. 1, the ink jet recording head 10 includes a nozzle plate 9, a plate 8 and
A vibration plate 6 extending parallel to the nozzle plate 9, adhesive layers 7 and 7 ′, and a piezoelectric element 5 are provided.

It should be noted that the side 9a of the nozzle plate 9 is in the X1 direction and in the opposite direction to the X1 direction (when the X1 direction is set to an angle of 0,
The side 9a of the nozzle plate 9 in the direction of angle 180) is the X2 direction, and the direction vertically upward with respect to the side 9a (the direction inclining to the angle θ ₁ when the X1 direction is angle 0) is the Y1 direction and the side 9a. The vertical downward direction (the direction inclining to the angle θ ₂ when the X1 direction is the angle 0) is defined as the Y2 direction. Also, X
When one direction is an angle 0, a direction inclined to the Y1 direction with respect to the X1 direction by an angle θ ₃ is a Y3 direction, a direction inclined by an angle θ ₄ is a Y4 direction, and a direction inclined by an angle θ ₅ is a Y5 direction, The direction inclining to the angle θ ₆ is the Y6 direction. Where θ
_{1 = 90 °, θ 2 =} 270 °, (180 ° -θ 4) = θ
₃ , (180 ° −θ ₆ ) = θ ₅ , 0 ° <θ ₃ <θ ₅ <θ
₁ <θ ₆ <θ ₄ <θ ₂ <360 °.

The plate 8 is provided and connected to the nozzle plate 9. The vibration plate 6 is provided on the plate 8.
Are provided and connected.

Nozzle plate 9, plate 8 and diaphragm 6
Is formed of a metal material such as nickel or stainless steel. The nozzle plate 9, the plate 8 and the vibrating plate 6 are not limited to a metal material, and may be a resin exemplified by polyimide or silicon. In this case, the combination of materials used for the nozzle plate 9, the plate 8 and the vibration plate 6 may be either free or the same in the above example. The optimum combination is selected as appropriate according to the requirements for designing the head.

Plate 8, nozzle plate 9 and diaphragm 6
Form a pressure chamber 2 for containing and pressurizing ink, and the pressure chamber 2 is filled with ink 11. The pressure chamber 2 has a bottom surface portion 2a, a top surface portion 2b, and side surface portions 2c and 2d. Here, the shape of the pressure chamber 2 is preferably a truncated pyramid (see FIG. 2). In this case, the side surface portion 2c and the side surface portion 2d are formed apart from each other. Further, the pressure chamber 2 is
It is preferable to further have a side surface portion (not shown) that connects the side surface portion 2c and the side surface portion 2d.

As shown in FIG. 1, the bottom surface portion 2 a is a surface in contact with the nozzle plate 9. The upper surface portion 2b is a surface that contacts the diaphragm 6. The side surface portion 2c extends from the bottom surface portion 2a to the upper surface portion 2b in the Y4 direction, and is a first portion showing the plate 8.
This is the surface that contacts the plate 8a. The side surface portion 2d is a surface that extends from the bottom surface portion 2a to the upper surface portion 2b in the Y3 direction and is in contact with the second plate 8b indicating the plate 8. The length of the top surface portion 2b in the X1 direction is longer than the length of the bottom surface portion 2a in the X1 direction.

Further, the plate 8, the nozzle plate 9 and the vibrating plate 6 form an ink pool 4 for accommodating ink and supplying / supplying to the pressure chamber 2, and the ink pool 4 is filled with the ink 13. There is. The ink pool 4 has a bottom surface portion 4a, a top surface portion 4b, and side surface portions 4c and 4d. Here, it is preferable that the shape of the ink pool 4 is a truncated pyramid (see FIG. 2). In this case, the side surface portion 4c and the side surface portion 4d
Are formed apart from each other. In addition, the ink pool 4
It is preferable to further include a side surface portion (not shown) that connects the side surface portion 4c and the side surface portion 4d.

As shown in FIG. 1, the bottom surface portion 4 a is a surface that contacts the nozzle plate 9. The upper surface portion 4b is a surface that contacts the diaphragm 6. The side surface portion 4c extends from the bottom surface portion 4a to the upper surface portion 4b in the Y3 direction, and shows the plate 8
This is the surface that contacts the plate 8b. The side surface portion 4d is a surface that extends from the bottom surface portion 4a to the upper surface portion 4b in the Y4 direction and is in contact with the third plate 8c indicating the plate 8. The length of the top surface portion 4b in the X1 direction is shorter than the length of the bottom surface portion 4a in the X1 direction.

The second plate 8b showing the plate 8 includes:
The ink pool 4 communicates with the pressure chamber 2, and the ink pool 4
A supply port 3 for replenishing / supplying the ink 13 accommodated in the pressure chamber 2 as the ink 11 is formed. The supply port 3 is a hole that penetrates the second plate 8b from the side surface portion 4c of the ink pool 4 to the side surface portion 2d of the pressure chamber 2 in the X2 direction, and has an inlet 3a, an outlet 3b, a top surface portion 3c, and a bottom surface portion 3d.
Have and. The inlet 3a is a side surface portion 4c of the ink pool 4.
Corresponds to the entrance of the hole penetrated by. The outlet 3b corresponds to the outlet of a hole that is penetrated by the side surface portion 2d of the pressure chamber 2. The upper surface portion 3c is a surface that extends from the inlet 3a to the outlet 3b and contacts the diaphragm 6. The bottom surface portion 3d is from the inlet 3a to the outlet 3b.
It is a surface that extends up to and contacts the second plate 8b.

The nozzle plate 9 is formed with nozzles 1 which communicate with the pressure chamber 2 and eject the ink 11 as ink droplets. The nozzle 1 includes the nozzle plate 9 from the center of the bottom surface 2a of the pressure chamber 2 to (the side 9a of) the nozzle plate 9 along the axis L of the center of the bottom surface 2a and the top surface 2b of the pressure chamber 2. It is an opening penetrating in the Y2 direction and has an inlet 1a, an outlet 1b, and side surface portions 1c and 1d. The inlet 1a corresponds to the inlet of an opening penetrating the center of the bottom surface 2a of the pressure chamber 2. The outlet 1b corresponds to the outlet of the opening penetrating the (the side 9a of) the nozzle plate 9 and ejects the ink 11 as an ink droplet. The side surface portion 1c extends from the outlet 1b in the Y4 direction to the inlet 1a,
This is the surface that contacts the nozzle plate 9. The side surface portion 1d extends from the outlet 1b in the Y3 direction to the inlet 1a and is in contact with the nozzle plate 9. The length of the inlet 1a in the X1 direction is
It is longer than the length of the outlet 1b in the X1 direction. Here, the shape of the nozzle 1 is preferably a truncated cone (see FIG. 2).
In this case, the side surface portion 1c and the side surface portion 1d are integrally formed.

The piezoelectric element 5 has a top surface portion 5a, a bottom surface portion 5b, and side surface portions 5c and 5d. Top part 5a, bottom part 5b
The length W in the X1 direction of is the same as the length in the X1 direction of the upper surface portion 2b of the pressure chamber 2. The positive electrode is thinly formed on the upper surface portion 5a, and the negative electrode is thinly formed on the bottom surface portion 5b.
The piezoelectric element 5 is polarized in advance by the polarization process. The pre-polarized piezoelectric element 5 is deformed based on the voltage applied between the top surface portion 5a and the bottom surface portion 5b.

The piezoelectric material forming the piezoelectric element 5 is usually
In the initial state (virgin material), it does not exhibit piezoelectricity. When an electric field having a predetermined value or more is externally applied (polarization processing), the piezoelectric element 5 exhibits a piezoelectric effect according to a minute electric field from the outside. In advance, as a polarization process, a positive voltage equal to or higher than a set value is applied to the upper surface portion 5a which is a positive electrode, and a negative voltage (usually ground) is applied to the bottom surface portion 5b which is a negative electrode. When a positive voltage is applied to 5a and a negative voltage (usually ground) is applied to the bottom surface portion 5b, it is driven so as to contract in the in-plane direction.

On the vibrating plate 6, adhesive layers 7 and 7'for partially joining the piezoelectric element 5 and the vibrating plate 6 are provided. The adhesive layer 7 and the adhesive layer 7 ′ are provided on the diaphragm 6. The adhesive layer 7 has a direction X1 perpendicular to the axis L.
Is provided in the direction away from the axis L by a distance s1 and has a length t1 in the X1 direction with respect to the axis L. Adhesive layer 7 '
In the X2 direction which is the direction perpendicular to the axis L, the axis L
Is separated from the axis L by a distance s2.
It has a directional length t2.

Here, the distance s1 is the same as the distance s2, and the length t1 of the adhesive layer 7 in the X1 direction with respect to the axis L is:
The length t2 of the adhesive layer 7'in the X2 direction with respect to the axis L is preferably the same. Also, the length W and the distances s1 and s
2. Unify the unit of length t1 and t2 (for example, meters)
In case of (W / 2) ≧ (s1 + t1), s1 ≧ t1,
It is preferable that (W / 2) ≧ (s2 + t2) and s2 ≧ t2.

The adhesive layers 7 and 7'are made of an adhesive material having excellent conductivity. An epoxy adhesive is exemplified as the adhesive material.

The piezoelectric element 5 is provided on the adhesive layers 7 and 7 '. The bottom surface portion 5b of the piezoelectric element 5 has an adhesive layer 7,
The diaphragm 7 is partially joined to the diaphragm 6.

Here, as shown in FIG. 2, when the piezoelectric element 5 has a circular shape, the piezoelectric element 5 has a radius (W × (1/2)) centered on the axis L. Is preferred. In this case, it is preferable that the adhesive layer (including the adhesive layer 7 and the adhesive layer 7 ′) is provided along the circumference of the circle of the piezoelectric element 5. Further, the adhesive layer (including the adhesive layer 7 and the adhesive layer 7 ′) has a radius (s1 + t1) centered on the axis L.
It is preferable that the shape is formed in a portion (area) excluding a circle centered on the axis L and having a radius s1. In addition, it is preferable that the adhesive layer 7 and the adhesive layer 7 ′ described above are integrally formed.

As shown in FIG. 1, when the piezoelectric element 5 moves / drives in the in-plane direction (when contracted) in accordance with the voltage applied between the top surface portion 5a and the bottom surface portion 5b, the piezoelectric element 5 Since 5 and the vibration plate 6 are partially bonded by the adhesive layers 7 and 7 ', the piezoelectric element 5 bonding surface of the vibration plate 6 is compressed in the in-plane direction. As a result, the bending moment M acts on the diaphragm 6, and the diaphragm 6 is flexibly deformed in the Y2 direction. At this time, since the piezoelectric element 5 and the vibrating plate 6 are joined only by the adhesive layers 7 and 7 ′, the vibrating plate 6 is not affected by the bending rigidity of the piezoelectric element 5 and the bending rigidity of its own. Accordingly, flexural deformation occurs in accordance with the bending moment M acting on the diaphragm 6. Thereby, the ink jet recording head 10 can pressurize the ink 11 with a low voltage by greatly improving the volume displacement of the pressure chamber 2.

The pressure inside the pressure chamber 2 changes (volume displacement) based on the movement / drive of the piezoelectric element 5 (deflection of the vibration plate 6). The ink droplets described above are ejected from the nozzle 1 based on the change in the pressure of the pressure chamber 2. The piezoelectric element 5 presses the pressure chamber 2 via the vibration plate 6 to eject the ink 11 from the nozzle 1 as an ink droplet. As described above, the ink jet recording head 10 enables the density and size of the pressure chambers 2 to be increased by significantly improving the volume displacement of the pressure chambers 2, and the ink 1 can be formed at a low voltage.
By pressurizing 1, it is possible to reduce the power consumption and the voltage of the head.

Next, the ink droplet ejection operation of the ink jet recording head 10 will be described with reference to FIG. FIG. 3 is a cross-sectional view showing the ink droplet ejection operation of the inkjet recording head according to the first embodiment.

As shown in FIG. 3, the ink jet recording head 10 is connected to the external power source 80. The positive electrode of the external power supply 80 is connected to the upper surface portion 5a, which is the positive electrode of the piezoelectric element 5, and the negative electrode of the external power supply 80 is connected to the diaphragm 6. Since the bottom surface portion 5b which is the negative electrode of the piezoelectric element 5 and the vibration plate 6 are bonded to the conductive adhesive layers 7 and 7 ', the vibration plate 6 is the negative electrode and is normally grounded by the external power supply 80. Has been done.

A voltage is applied between the upper surface 5a (positive electrode) of the piezoelectric element 5 and the diaphragm 6 (negative electrode) by the external power supply 80. The voltage applied by the external power supply 80 is 40
It is preferably less than (V), for example, 30 (V).

Here, the ink jet recording head 10 shown in FIG. 1 is in a state in which no voltage is applied by the external power source 80, and this state is called a stationary state. Also,
The inkjet recording head 10 shown in FIG. 3 is in a state in which a voltage is applied by the external power supply 80, and this state is called an operating state.

First, in the stationary state, as a voltage is applied to the piezoelectric element 5, the upper surface portion 5a (positive electrode) of the piezoelectric element 5 is
When a voltage is applied between the diaphragm and the diaphragm 6 (negative electrode) by the external power supply 80, the piezoelectric element 5 contracts in the directions of arrows a and b (contracting operation), and the adhesive layers 7 and 7 ′ are used. , Diaphragm 6
The bonding surface of the piezoelectric element 5 is compressed in the in-plane direction. as a result,
The bending moment M acts on the diaphragm 6,
The diaphragm 6 causes flexural deformation in the Y2 direction (flexural deformation operation). As a result, the inkjet recording head 10
Move to operating state.

In the contraction operation of the piezoelectric element 5, the piezoelectric element 5
Of the piezoelectric element 5 contracts from one of both ends of the piezoelectric element 5 toward the axis L in the direction of the arrow a parallel to the X2 direction.
Contracts from the other of both ends toward the axis L in the direction of arrow b parallel to the X1 direction.

Next, in the operating state, in the pressure chamber 2,
Bending and deforming operation of the diaphragm 6 (when the upper surface 2b of the pressure chamber 2 is Y2
The ink 11 in the pressure chamber 2 is compressed by the volume displacement due to the bending (in the direction). As a result, the inkjet recording head 10 can eject the ink 11 as the ink droplet 12 from the nozzle 1 communicating with the pressure chamber 2.

Next, in the operating state, the external power source 80
The upper surface 5a (positive electrode) of the piezoelectric element 5 and the vibration plate 6
When the voltage applied to the (negative electrode) is set to 0 (V) (the voltage applied to the piezoelectric element 5 is returned to the original value), the inkjet recording head 10 shifts to the stationary state and the piezoelectric element 5 The diaphragm 6 returns to the original state shown in FIG. 1 (deflection ending operation). In the pressure chamber 2, due to the restoring force (capillary force) of the meniscus of the ink formed in the nozzle 1, the ink 13 in the ink pool 4 is supplied / supplied into the pressure chamber 2 through the supply port 3. .

Thus, the ink jet recording head 1
At 0, since the piezoelectric element 5 and the vibration plate 6 are partially bonded by the adhesive layers 7 and 7 ′, the piezoelectric element 5 and the vibration plate 6 are
Can have different curvatures, and the piezoelectric element 5 itself can largely bend the diaphragm 6 without much bending.

For example, the piezoelectric element 5 has a diameter of 0.4 mm and a thickness of 30 μm, and the vibrating plate 6 has a portion diameter of the pressure chamber 2 of 0.5 m.
When m, the thickness is 10 μm, and the thicknesses of the adhesive layers 7 and 7 ′ are 5 μm, the embodiment of the present invention can obtain a volume displacement about twice as much as that of the conventional example. Therefore, by using the embodiment of the present invention, the occupied area of the pressure chamber 2 can be reduced to about 1/2 of that of the conventional example (pressure chamber 102), and the density can be doubled.

As described above, according to the ink jet recording head 10 according to the first embodiment, the volume displacement of the pressure chamber 2 is increased in order to pressurize the ink 11 without increasing the occupied area of the pressure chamber 2. By improving, the density of the pressure chambers 2 can be increased.

Further, according to the ink jet recording head 10 according to the first embodiment, the piezoelectric element 5 is driven at a low voltage without increasing the energy generated in the piezoelectric element 5, and the pressure for pressurizing the ink 11 is applied. By drastically improving the volume displacement of the chamber 2, it is possible to eject liquid droplets, and it is possible to reduce the power consumption and the voltage of the head.

Further, according to the ink jet recording head 10 of the first embodiment, the density of the pressure chambers 2 can be increased, so that the number of nozzles can be increased and the speed can be increased without increasing the size of the head. Can be achieved.

The ink jet recording head 10 according to the first embodiment is not limited to the above description. The adhesive layer (including the adhesive layer 7 and the adhesive layer 7 ') is shown in FIG.
The shape is not limited to that shown in FIG.
The piezoelectric element 5 is preferably provided at a predetermined position along the circumference of the circle. Further, the adhesive layer (including the adhesive layer 7 and the adhesive layer 7 ') has a radius (s1 + t1) about the axis L.
On the circumference of × (1/2)), a predetermined distance, for example, the axis L
It is preferable that the shape is partially formed with an interval of 45 degrees around the center. In this case, it is preferable that the adhesive layer 7 and the adhesive layer 7 ′ described above are formed apart from each other.

The piezoelectric element 5 shown in FIG. 4 is not limited to the circular shape, but may be a square shape as shown in FIG. In this case, the piezoelectric element 5 having a square shape has lengths W of four sides, respectively, and is provided so that the intersections of the two diagonal lines correspond to the axis L, and two of the four sides are X1. It is preferably provided in parallel with the direction (or the X2 direction). Further, the adhesive layer (including the adhesive layer 7 and the adhesive layer 7 ′) is preferably provided along at least two sides of the four sides of the square of the piezoelectric element 5.
Further, the adhesive layer (including the adhesive layer 7 and the adhesive layer 7 ′) is
Each of the four sides has a length (s1 + t1 + s2 + t2), and the intersections of the two diagonals are provided so as to correspond to the axis L. Two of the four sides are provided parallel to the X1 direction (or the X2 direction). From the square, the length of each of the four sides (s
1 + s2), and the intersections of the two diagonal lines are provided so as to correspond to the axis L, and two of the four sides except for the square provided parallel to the X1 direction (or the X2 direction) ( The shape is preferably formed in a region. In addition, it is preferable that the adhesive layer 7 and the adhesive layer 7 ′ described above are integrally formed.

When the piezoelectric element 5 shown in FIG. 5 has a square shape, the adhesive layer (including the adhesive layer 7 and the adhesive layer 7 ′) is at least one of the four sides of the square of the piezoelectric element 5. Two
It is preferably provided at a predetermined position along the side. Furthermore, the adhesive layer (including the adhesive layer 7 and the adhesive layer 7 ') is not limited to the shape shown in FIG. 5, and as shown in FIG. The shape is preferably partially formed at intervals of 45 degrees. In this case, it is preferable that the adhesive layer 7 and the adhesive layer 7 ′ described above are formed apart from each other.

Further, the piezoelectric element 5 shown in FIG. 5 is not limited to the square shape, and as shown in FIG.
It may be rectangular. In this case, in the rectangular piezoelectric element 5, two of the four sides are longer than the two sides having the length W, and the two sides of the four sides having the length W are in the X1 direction (or the X2 direction). Is preferably provided in parallel with.
In addition, the adhesive layer (including the adhesive layer 7 and the adhesive layer 7 ′) is preferably provided along two sides longer than the two sides having the length W among the four sides of the rectangle of the piezoelectric element 5. . Further, it is preferable that the adhesive layer 7 and the adhesive layer 7 ′ described above are formed so as to extend in the vertical direction on the same plane in the X1 direction. In this case, it is preferable that the adhesive layer 7 and the adhesive layer 7 ′ described above are formed apart from each other.

Further, the shapes of the pressure chamber 2 and the ink pool 4 shown in FIG. 2 are not limited to the truncated pyramids as shown in FIG. 8, and may be truncated cones. In this case, it is preferable that the side surface portion 2c and the side surface portion 2d be integrally formed, and the side surface portion 4c and the side surface portion 4d be integrally formed. In addition, the piezoelectric element 5
Is preferably a circle having a radius (W × (1/2)) centered on the axis L. Further, the adhesive layer (including the adhesive layer 7 and the adhesive layer 7 ′) is preferably provided along the circumference of the circle of the piezoelectric element 5. Further, the adhesive layer (including the adhesive layer 7 and the adhesive layer 7 ′) is formed from a circle having a radius (s1 + t1) centered on the axis L to a radius s1 centered on the axis L.
The shape is preferably formed in a portion (area) excluding the circle. In addition, it is preferable that the adhesive layer 7 and the adhesive layer 7 ′ described above are integrally formed.

When the pressure chamber 2 and the ink pool 4 shown in FIG. 8 have a truncated cone shape, the adhesive layer (including the adhesive layer 7 and the adhesive layer 7 ') is shown in FIG. The shape is not limited, and as shown in FIG. 9, it is preferable that the piezoelectric element 5 is provided at a predetermined position along the circumference of the circle. Furthermore, the adhesive layer (including the adhesive layer 7 and the adhesive layer 7 ′) is provided with a predetermined distance, for example, the axis L, on the circumference of a radius (s1 + t1 × (1/2)) centered on the axis L. The shape is preferably partially formed at intervals of 45 degrees in the center. In this case, it is preferable that the adhesive layer 7 and the adhesive layer 7 ′ described above are formed apart from each other.

The ink jet recording head 10 according to the first embodiment is not limited to the piezoelectric element 5 as long as it is an element that presses the pressure chamber 2 via the vibration plate 6. Diaphragm 6
The element for pressing the pressure chamber 2 via the electrostrictive element,
Magnetostrictive elements and shape memory alloys are exemplified. In this case, when any of the electrostrictive element, the magnetostrictive element, and the shape memory alloy moves / drives in the a and b directions instead of the piezoelectric element 5, any of the electrostrictive element, the magnetostrictive element, and the shape memory alloy, It is preferable that the pressure inside the pressure chamber 2 be changed by pressing the pressure chamber 2 via the vibrating plate 6 so that the ink 11 is ejected from the nozzle 1 as an ink droplet 12.

(Second Embodiment) An ink jet recording head 20 according to the second embodiment will be described with reference to FIG. FIG. 10 is a sectional view showing the ink jet recording head according to the second embodiment.

As shown in FIG. 10, the ink jet recording head 20 includes a nozzle plate 9 and a plate 8.
A vibration plate 26 extending parallel to the nozzle plate 9, adhesive layers 27 and 27 ', and a piezoelectric element 25. Here, in the second embodiment, description that overlaps with the first embodiment will be omitted.

On the plate 8, a vibration plate 26 is provided and connected instead of the vibration plate 6.

The diaphragm 26 is made of a metal material such as nickel or stainless. The diaphragm 2
6 is not limited to a metal material, and may be a resin exemplified by polyimide, or silicon may be used. in this case,
The combination of materials used for the nozzle plate 9, the plate 8 and the vibrating plate 26 may be either free or the same in the above example. The optimum combination is selected as appropriate according to the requirements for designing the head.

Plate 8, nozzle plate 9 and diaphragm 2
Reference numeral 6 forms a pressure chamber 2 for containing and pressurizing ink, and the pressure chamber 2 is filled with ink 11. The upper surface portion 2b of the pressure chamber 2 is a surface in contact with the vibration plate 26. Here, the shape of the pressure chamber 2 is preferably a truncated pyramid (see FIG. 11). In this case, the side surface portion 2c and the side surface portion 2d are formed apart from each other. In addition, the pressure chamber 2 has a side surface 2
It is preferable to further include a side surface portion (not shown) that connects c with the side surface portion 2d.

Further, the plate 8, the nozzle plate 9 and the vibrating plate 26 form an ink pool 4 for accommodating the ink and supplying / supplying it to the pressure chamber 2, and the ink pool 4 is filled with the ink 13. There is. The upper surface portion 4b of the ink pool 4 is a surface in contact with the vibration plate 26. Here, the shape of the ink pool 4 is preferably a truncated pyramid (FIG. 1).
1). In this case, the side surface portion 4c and the side surface portion 4d are formed apart from each other. In addition, the ink pool 4 includes the side surface portion 4
It is preferable to further have a side surface portion (not shown) that connects c with the side surface portion 4d.

The second plate 8b showing the plate 8 includes:
The ink pool 4 communicates with the pressure chamber 2, and the ink pool 4
A supply port 3 for replenishing / supplying the ink 13 accommodated in the pressure chamber 2 as the ink 11 is formed. Here, the upper surface portion 3c of the supply port 3 is a surface in contact with the vibration plate 26.

The nozzle plate 9 is formed with nozzles 1 communicating with the pressure chambers 2 for ejecting the ink 11 as ink droplets. Here, the shape of the nozzle 1 is preferably a truncated cone (see FIG. 11). In this case, the side surface portion 1c and the side surface portion 1d are integrally formed.

The piezoelectric element 25 includes a top surface portion 25a and a bottom surface portion 2
5b and side surface portions 25c and 25d. Piezoelectric element 25
The length W of the top surface portion 25a and the bottom surface portion 25b in the X1 direction is
It is the same as the length of the upper surface portion 2b of the pressure chamber 2 in the X1 direction.
The positive electrode is thinly formed on the upper surface portion 25a, the negative electrode is thinly formed on the bottom surface portion 25b, and the piezoelectric element 25 is pre-polarized by the polarization treatment. The pre-polarized piezoelectric element 25 deforms based on the voltage applied between the top surface portion 25a and the bottom surface portion 25b.

Further, similarly to the first embodiment, as the polarization process, a positive voltage equal to or higher than a set value is applied to the upper surface 25a, which is a positive electrode, and a negative voltage (usually ground) is applied to the bottom surface 25b, which is a negative electrode. , The piezoelectric element 25 has a positive voltage on the top surface 25a and a negative voltage on the bottom surface 25b (usually grounded).
Is driven so as to contract in the directions of arrows a and b.

The diaphragm 26 has grooves 26a and 26b formed on the surface of the diaphragm 26. An adhesive layer 27 for partially bonding the piezoelectric element 25 and the vibration plate 26 is provided in the groove 26a, and an adhesive layer 27 'for partially bonding the piezoelectric element 25 and the vibration plate 26 is provided in the groove 26b. It is provided. The groove 26a is provided at a distance s1 from the axis L in the X1 direction which is a direction perpendicular to the axis L, and has a length t1 in the X1 direction with respect to the axis L. Groove 2
6b is provided at a distance s2 from the axis L in the X2 direction which is a direction perpendicular to the axis L, and has a length t2 in the X2 direction with respect to the axis L. The adhesive layer 27 is provided in the groove 26a at a distance s1 from the axis L in the X1 direction and has a length t1 in the X1 direction with respect to the axis L. The adhesive layer 7'is provided in the groove 26b at a distance s2 from the axis L in the X2 direction, and has a length t in the X2 direction with respect to the axis L.
Have two.

Here, the distance s1 is the same as the distance s2, and the length t1 of the adhesive layer 27 in the X1 direction with respect to the axis L.
Is the length t2 of the adhesive layer 27 'in the X2 direction with respect to the axis L.
Is preferably the same as Also, length W, distance s
When the units of 1, s2 and lengths t1 and t2 are unified (for example, meters), (W / 2) ≧ (s1 + t1), s1 ≧
It is preferable that t1, (W / 2) ≧ (s2 + t2), and s2 ≧ t2.

The adhesive layers 27 and 27 'are adhesive materials having excellent conductivity. An epoxy adhesive is exemplified as the adhesive material.

A piezoelectric element 25 is provided on the vibrating plate 26 and the adhesive layers 27 and 27 '. The bottom surface portion 25b of the piezoelectric element 25 is partially bonded to the vibration plate 26 by the adhesive layers 27 and 27 '.

Here, as shown in FIG. 11, when the piezoelectric element 25 has a circular shape, the piezoelectric element 25 is a circle having a radius (W × (1/2)) centered on the axis L. Is preferred. In this case, it is preferable that the adhesive layer (including the adhesive layer 27 and the adhesive layer 27 ′) and the groove (including the groove 26 a and the groove 26 b) be provided along the circumference of the circle of the piezoelectric element 25. Further, the adhesive layer (including the adhesive layer 27 and the adhesive layer 27 ′) and the groove (including the groove 26a and the groove 26b) are separated from the circle having the radius (s1 + t1) centered on the axis L from the axis L
It is preferable that the shape is formed in a portion (area) excluding a circle having a radius s1 centered at. The adhesive layer 27 and the adhesive layer 27 'described above are preferably formed integrally. The groove 26a and the groove 26b described above are preferably formed integrally.

As shown in FIG. 10, when the piezoelectric element 25 moves / drives (in a contracted state) in the in-plane direction according to the voltage applied between the top surface portion 25a and the bottom surface portion 25b,
Since the piezoelectric element 25 and the vibrating plate 26 are partially bonded by the adhesive layers 27 and 27 ', the piezoelectric element 25 adhering surface of the vibrating plate 26 is compressed in the in-plane direction. As a result, the bending moment M acts on the diaphragm 26, and the diaphragm 26 is flexibly deformed in the Y2 direction. At this time, since the piezoelectric element 25 and the vibrating plate 26 are bonded only by the adhesive layers 27 and 27 ', the vibrating plate 26 is not affected by the bending rigidity of the piezoelectric element 25, and the bending rigidity of its own. Accordingly, flexural deformation occurs in accordance with the bending moment M acting on the diaphragm 26. As a result, the inkjet recording head 2
0 significantly pressurizes the ink 11 with a low voltage by significantly improving the volume displacement of the pressure chamber 2.

The pressure inside the pressure chamber 2 changes (volume displacement) based on the movement / drive of the piezoelectric element 25 (deflection of the vibration plate 26). The ink droplets described above are ejected from the nozzle 1 based on the change in the pressure of the pressure chamber 2. Piezoelectric element 2
5 presses the pressure chamber 2 via the vibration plate 26 to eject the ink 11 from the nozzle 1 as an ink droplet. In this way, the ink jet recording head 20 enables a high density and a small size in the arrangement of the pressure chambers 2 by significantly improving the volume displacement of the pressure chambers 2, and by pressurizing the ink 11 with a low voltage. It enables low power consumption and low voltage of the head.

Next, the ink droplet ejection operation of the ink jet recording head 20 will be described with reference to FIG. FIG. 12 is a cross-sectional view showing the ink droplet ejection operation of the inkjet recording head according to the second embodiment.

As shown in FIG. 12, the ink jet recording head 20 is connected to the external power source 80. An external power source 80 is provided on the upper surface portion 25a which is the positive electrode of the piezoelectric element 25.
Of the external power source 80 is connected to the vibration plate 26. Bottom part 2 which is the negative electrode of the piezoelectric element 25
Since 5b and the diaphragm 26 are bonded to the conductive adhesive layers 27 and 27 ', the diaphragm 26 is a negative electrode and is normally grounded by the external power supply 80.

A voltage is applied between the upper surface portion 25a (positive electrode) of the piezoelectric element 25 and the vibrating plate 26 (negative electrode) by the external power supply 80. The voltage applied by the external power supply 80 is preferably less than 40 (V), for example, 30 (V), as in the first embodiment.

Here, the ink jet recording head 20 shown in FIG. 10 is in a state where no voltage is applied by the external power source 80, and this state is called a stationary state. Further, the inkjet recording head 20 shown in FIG.
Is a state in which a voltage is applied by the external power supply 80,
This state is called an operating state.

First, in the stationary state, as a voltage application to the piezoelectric element 25, a voltage is applied between the upper surface portion 25a (positive electrode) of the piezoelectric element 25 and the vibration plate 26 (negative electrode) by the external power supply 80. At this time, the piezoelectric element 25 contracts in the directions of the arrows a and b (contraction operation), and the piezoelectric element 25 adhesive surface of the vibration plate 26 is compressed in the in-plane direction via the adhesive layers 27 and 27 '. As a result, the bending moment M acts on the vibration plate 26, and the vibration plate 26 causes bending deformation in the Y2 direction (flexing deformation operation). As a result, the inkjet recording head 20 shifts to the operating state.

In the contraction operation of the piezoelectric element 25, the piezoelectric element 2
5 contracts from one of the two ends of the piezoelectric element 25 in the direction of arrow a parallel to the X2 direction toward the axis L, and from the other of the two ends of the piezoelectric element 25 parallel to the X1 direction toward the axis L. Contract in the direction of the arrow b.

Next, in the operating state, in the pressure chamber 2,
The flexure deformation operation of the diaphragm 26 (the upper surface portion 2b of the pressure chamber 2 is Y
The ink 11 in the pressure chamber 2 is compressed by the volume displacement due to the bending in two directions). As a result, the inkjet recording head 20 can eject the ink 11 as the ink droplet 12 from the nozzle 1 communicating with the pressure chamber 2.

Next, in the operating state, the external power source 80
As a result, the voltage applied between the upper surface portion 25a (positive electrode) of the piezoelectric element 25 and the vibrating plate 26 (negative electrode) is reduced to zero.
When set to (V) (when the voltage applied to the piezoelectric element 25 is returned to the original state), the inkjet recording head 20 shifts to the stationary state, and the piezoelectric element 25 and the diaphragm 26 return to the original state shown in FIG. Return (deflection end operation). In the pressure chamber 2, due to the restoring force (capillary force) of the meniscus of the ink formed in the nozzle 1, the ink 13 in the ink pool 4 is supplied / supplied into the pressure chamber 2 through the supply port 3. .

In this way, the ink jet recording head 2
At 0, the piezoelectric element 25 and the vibration plate 26 have the adhesive layers 27, 2
Since it is partially bonded by 7 ', the piezoelectric element 25
The vibrating plate 26 and the vibrating plate 26 can have different curvatures, and the vibrating plate 26 can be largely bent without the piezoelectric element 25 itself being greatly bent.

From the above description, according to the ink jet recording head 20 according to the second embodiment, the same effect as that of the first embodiment can be obtained.

The ink jet recording head 20 according to the second embodiment is not limited to the above description. An adhesive layer (including an adhesive layer 27 and an adhesive layer 27 '),
The groove (including the groove 26a and the groove 26b) is not limited to the shape shown in FIG. 11, and is provided at a predetermined position along the circumference of the circle of the piezoelectric element 25 as shown in FIG. It is preferable. Further, the adhesive layer (including the adhesive layer 27 and the adhesive layer 27 ′) and the groove (including the groove 26a and the groove 26b) are
It is preferable that the shape is partially formed on a circumference of a radius (s1 + t1 × (1/2)) centered on the axis L at a predetermined distance, for example, at intervals of 45 degrees centered on the axis L.
In this case, it is preferable that the adhesive layer 27 and the adhesive layer 27 ′ described above are formed apart from each other. Groove 26a and groove 2 described above
6b is preferably formed separately from each other.

Further, the piezoelectric element 25 shown in FIG.
The shape is not limited to the circular shape, and may be a square shape as shown in FIG. In this case, the piezoelectric element 25 having a square shape has lengths W of four sides and 2
The intersection of the diagonal lines of the book is provided so as to correspond to the axis L,
It is preferable that two of the four sides are provided parallel to the X1 direction (or the X2 direction). The adhesive layer (including the adhesive layer 27 and the adhesive layer 27 ′) and the groove (including the groove 26 a and the groove 26 b) are provided along at least two sides of the four sides of the square of the piezoelectric element 25. Preferably. Further, an adhesive layer (including an adhesive layer 27 and an adhesive layer 27 '),
The groove (including the groove 26a and the groove 26b) has a length (s1 + t1 + s2 + t2) of each of four sides, and is provided so that the intersection of two diagonals corresponds to the axis L, and two of the four sides are provided. From a square whose sides are parallel to the X1 direction (or the X2 direction), each side has four lengths (s1 + s2), and the intersections of the two diagonal lines are provided so as to correspond to the axis L. It is preferable that two of the sides have a shape formed in a portion (area) other than a square provided parallel to the X1 direction (or the X2 direction). In addition, the above-mentioned adhesive layer 27
The adhesive layer 27 'and the adhesive layer 27' are preferably integrally formed. The groove 26a and the groove 26b described above are preferably formed integrally.

When the piezoelectric element 25 shown in FIG. 14 has a square shape, the adhesive layer (including the adhesive layer 27 and the adhesive layer 27 ') and the groove (including the groove 26a and the groove 26b) are It is preferable that the piezoelectric element 25 is provided at a predetermined position along at least two of the four sides of the square. Furthermore,
Adhesive layer (including adhesive layer 27 and adhesive layer 27 '), (groove 2
The groove (including 6a and the groove 26b) is not limited to the shape shown in FIG. 14, and as shown in FIG.
For example, it is preferable that the shape is partially formed at intervals of 45 degrees around the axis L. In this case, it is preferable that the adhesive layer 27 and the adhesive layer 27 ′ described above are formed apart from each other. It is preferable that the groove 26a and the groove 26b described above are formed apart from each other.

Further, the piezoelectric element 25 shown in FIG.
The shape is not limited to the square shape, and may be a rectangular shape as shown in FIG. In this case, in the rectangular piezoelectric element 25, two of the four sides are longer than the two sides having the length W, and the two sides of the four sides having the length W are X.
It is preferably provided in parallel to one direction (or X2 direction). Further, the adhesive layer (including the adhesive layer 27 and the adhesive layer 27 ′) and the groove (including the groove 26 a and the groove 26 b) are defined by the two sides having the length W of the four sides of the rectangle of the piezoelectric element 25. It is preferably provided along two long sides. Furthermore, the adhesive layer 27 and the adhesive layer 27 'described above, and the groove 26a described above.
The groove 26b is preferably formed so as to extend in the vertical direction on the same plane in the X1 direction. In this case, it is preferable that the adhesive layer 27 and the adhesive layer 27 ′ described above are formed apart from each other. It is preferable that the groove 26a and the groove 26b described above are formed apart from each other.

Further, the shape of the pressure chamber 2 and the ink pool 4 shown in FIG. 11 is not limited to the quadrangular truncated pyramid as shown in FIG. 17, and may be a truncated cone. In this case, the side surface portion 2c
And the side surface portion 2d are integrally formed, and the side surface portion 4c and the side surface portion 4 are formed.
It is preferable that d is integrally formed. Further, the piezoelectric element 25 is preferably a circle having a radius (W × (1/2)) centered on the axis L. The adhesive layer (including the adhesive layer 27 and the adhesive layer 27 ′) and the groove (including the groove 26 a and the groove 26 b) are preferably provided along the circumference of the circle of the piezoelectric element 25. Furthermore, (adhesive layer 27 and adhesive layer 2
The adhesive layer (including 7 ′) and the groove (including the groove 26 a and the groove 26 b) are a portion of a circle having a radius (s1 + t1) centered on the axis L and excluding a circle having a radius s1 centered on the axis L. The shape is preferably formed in (region). In addition, it is preferable that the adhesive layer 7 and the adhesive layer 7 ′ described above are integrally formed. The groove 26a and the groove 26b described above are preferably formed integrally.

When the pressure chamber 2 and the ink pool 4 shown in FIG. 17 have a truncated cone shape, an adhesive layer (including the adhesive layer 27 and the adhesive layer 27 '), (a groove 26a and a groove 26b). The groove is not limited to the shape shown in FIG. 17, but is preferably provided at a predetermined position along the circumference of the circle of the piezoelectric element 25 as shown in FIG. Furthermore,
Adhesive layer (including adhesive layer 27 and adhesive layer 27 '), (groove 2
The groove 6a and the groove 26b are partially formed on the circumference of a radius (s1 + t1 × (1/2)) centered on the axis L at a predetermined distance, for example, at intervals of 45 degrees centered on the axis L. The shape may be a shape formed in. In this case, the above-mentioned adhesive layer 2
7 and the adhesive layer 27 'are preferably formed apart from each other. It is preferable that the groove 26a and the groove 26b described above are formed apart from each other.

The ink jet recording head 20 according to the second embodiment is not limited to the piezoelectric element 25 as long as it is an element that presses the pressure chamber 2 via the vibration plate 26. Examples of the element that presses the pressure chamber 2 via the diaphragm 26 include an electrostrictive element, a magnetostrictive element, and a shape memory alloy. In this case, when any of the electrostrictive element, the magnetostrictive element, and the shape memory alloy moves / drives in the a and b directions instead of the piezoelectric element 25, any of the electrostrictive element, the magnetostrictive element, and the shape memory alloy,
By pressing the pressure chamber 2 via the diaphragm 26,
It is preferable to change the pressure inside the pressure chamber 2 and eject the ink 11 from the nozzle 1 as an ink droplet.

(Third Embodiment) An ink jet recording head 30 according to the third embodiment will be described with reference to FIG. FIG. 19 is a sectional view showing the ink jet recording head according to the third embodiment.

As shown in FIG. 19, the ink jet recording head 30 includes a nozzle plate 9 and a plate 8.
A vibration plate 36 extending parallel to the nozzle plate 9, adhesive layers 37 and 37 ′, and a piezoelectric element 35. Here, in the third embodiment, description that overlaps with the first embodiment will be omitted.

A vibrating plate 36 is provided and connected on the plate 8 instead of the vibrating plate 6.

The diaphragm 36 is made of a metal material such as nickel or stainless. The diaphragm 3
6 is not limited to a metal material, and may be a resin exemplified by polyimide, or silicon may be used. in this case,
Nozzle plate 9, first plate 8a, and second plate 8
The combination of the materials used for b, the third plate 8c, and the vibration plate 36 may be arbitrary or the same in the above example. The optimum combination is selected as appropriate according to the requirements for designing the head.

Plate 8, nozzle plate 9 and diaphragm 3
Reference numeral 6 forms a pressure chamber 2 for containing and pressurizing ink, and the pressure chamber 2 is filled with ink 11. The upper surface portion 2b of the pressure chamber 2 is a surface in contact with the vibration plate 36. Here, the shape of the pressure chamber 2 is preferably a truncated pyramid (see FIG. 20). In this case, the side surface portion 2c and the side surface portion 2d are formed apart from each other. In addition, the pressure chamber 2 has a side surface 2
It is preferable to further include a side surface portion (not shown) that connects c with the side surface portion 2d.

Further, the plate 8, the nozzle plate 9 and the vibrating plate 36 form an ink pool 4 for accommodating ink and replenishing / supplying the pressure chamber 2, and the ink pool 4 is filled with the ink 13. There is. The upper surface portion 4b of the ink pool 4 is a surface in contact with the vibration plate 36. Here, the shape of the ink pool 4 is preferably a truncated pyramid (FIG. 2).
0). In this case, the side surface portion 4c and the side surface portion 4d are formed apart from each other. In addition, the ink pool 4 includes the side surface portion 4
It is preferable to further have a side surface portion (not shown) that connects c with the side surface portion 4d.

The second plate 8b showing the plate 8 includes:
The ink pool 4 communicates with the pressure chamber 2, and the ink pool 4
A supply port 3 for replenishing / supplying the ink 13 accommodated in the pressure chamber 2 as the ink 11 is formed. Here, the upper surface portion 3c of the supply port 3 is a surface in contact with the vibration plate 36.

The nozzle plate 9 is formed with nozzles 1 which communicate with the pressure chamber 2 and eject the ink 11 as ink droplets. Here, the shape of the nozzle 1 is preferably a truncated cone (see FIG. 20). In this case, the side surface portion 1c and the side surface portion 1d are integrally formed.

The piezoelectric element 35 has a top surface portion 35a and a bottom surface portion 3
5b and side surface portions 35c and 35d. Piezoelectric element 35
The length W of the top surface portion 35a and the bottom surface portion 35b in the X1 direction is
It is the same as the length of the upper surface portion 2b of the pressure chamber 2 in the X1 direction.
The positive electrode is thinly formed on the upper surface portion 35a, the negative electrode is thinly formed on the bottom surface portion 35b, and the piezoelectric element 35 is pre-polarized by the polarization process. The pre-polarized piezoelectric element 35 is deformed based on the voltage applied between the top surface portion 35a and the bottom surface portion 35b.

Further, similarly to the first embodiment, as a polarization process, a positive voltage equal to or higher than a set value is applied to the upper surface 35a, which is a positive electrode, and a negative voltage (usually ground) is applied to the bottom surface 35b, which is a negative electrode. , The piezoelectric element 35 has a positive voltage applied to the upper surface portion 35a and a negative voltage applied to the bottom surface portion 35b (usually grounded).
Is driven so as to contract in the directions of arrows a and b.

The vibrating plate 36 is formed with protrusions 36a and 36b provided on the surface of the vibrating plate 36. An adhesive layer 37 for partially bonding the piezoelectric element 35 and the vibration plate 36 is provided on the protrusion 36a, and an adhesive layer 37 for partially bonding the piezoelectric element 35 and the vibration plate 36 on the protrusion 36b. A layer 37 'is provided. The protrusion 36a is provided at a distance s1 from the axis L in the X1 direction which is a direction perpendicular to the axis L, and has a length t1 in the X1 direction with respect to the axis L. The protrusion 36b is provided at a distance s2 from the axis L in the X2 direction which is a direction perpendicular to the axis L, and has a length t2 in the X2 direction with respect to the axis L. The adhesive layer 37 is provided on the protrusion 36a at a distance s1 from the axis L in the X1 direction, and is provided on the axis L with respect to X1.
It has a directional length t1. The adhesive layer 37 ′ is provided on the protrusion 36b at a distance s2 from the axis L in the X2 direction, and has a length t2 in the X2 direction with respect to the axis L.

Here, the distance s1 is the same as the distance s2, and the length of the adhesive layer 37 in the X1 direction with respect to the axis L (the length of the protrusion 36a in the X1 direction with respect to the axis L) t1 is equal to that of the adhesive layer 37 '. Length in the X2 direction with respect to the axis L (projection 3
6b is preferably the same as the length in the X2 direction) t2 with respect to the axis L. When the units of the length W, the distances s1 and s2, and the lengths t1 and t2 are unified (for example, meters), (W / 2) ≧ (s1 + t1), s1 ≧ t1, (W /
It is preferable that 2) ≧ (s2 + t2) and s2 ≧ t2.

The adhesive layers 37 and 37 'are adhesive materials having excellent conductivity. An epoxy adhesive is exemplified as the adhesive material.

The piezoelectric element 35 is formed on the adhesive layers 37 and 37 '.
Is provided. The bottom surface portion 35b of the piezoelectric element 35 is partially bonded to the vibration plate 36 by the adhesive layers 37 and 37 '.

Here, as shown in FIG. 20, when the piezoelectric element 35 has a circular shape, the piezoelectric element 35 is a circle having a radius (W × (1/2)) centered on the axis L. Is preferred. In this case, an adhesive layer (including an adhesive layer 37 and an adhesive layer 37 '), (including a protrusion 36a and a protrusion 36b)
The protrusions are preferably provided along the circumference of the circle of the piezoelectric element 35. Further, (the adhesive layer 37 and the adhesive layer 3
Adhesive layer (including 7 '), (protrusion 36a and protrusion 36b)
The projections (including and) have a radius (s1 +
It is preferable that the shape is formed in a portion (area) excluding the circle of radius s1 centered on the axis L from the circle of t1). It is preferable that the adhesive layer 37 and the adhesive layer 37 ′ described above are integrally formed. The above-mentioned protrusion 36a and protrusion 36b
Are preferably integrally formed.

As shown in FIG. 19, when the piezoelectric element 35 is moved / driven in the in-plane direction (when contracted) in accordance with the voltage applied between the top surface portion 35a and the bottom surface portion 35b,
Since the piezoelectric element 35 and the vibration plate 36 are partially joined by the adhesive layers 37 and 37 'via the protrusions 36a and 36b, the piezoelectric element 35 bonding surface of the vibration plate 36 is compressed in the in-plane direction. . As a result, the bending moment M acts on the diaphragm 36, and the diaphragm 36 is flexibly deformed in the Y2 direction. At this time, the piezoelectric element 35 and the vibration plate 36
Is bonded only by the adhesive layers 37 and 37 ′, the vibration plate 36 is not affected by the bending rigidity of the piezoelectric element 35, and has a bending moment M acting on the vibration plate 36 according to its bending rigidity. In response, it causes bending deformation. As a result, the ink jet recording head 30 significantly improves the volume displacement of the pressure chamber 2 and thereby the ink 11 at a low voltage.
Can be pressurized.

In the pressure chamber 2, the internal pressure changes (volume displacement) based on the movement / drive of the piezoelectric element 35 (deflection of the vibration plate 36). The ink droplets described above are ejected from the nozzle 1 based on the change in the pressure of the pressure chamber 2. Piezoelectric element 3
5 presses the pressure chamber 2 through the vibrating plate 36 to eject the ink 11 from the nozzle 1 as an ink droplet. As described above, the ink jet recording head 30 enables the density and size of the pressure chamber 2 to be increased by significantly improving the volume displacement of the pressure chamber 2, and by pressurizing the ink 11 at a low voltage. It enables low power consumption and low voltage of the head.

Next, the ink droplet ejection operation of the ink jet recording head 30 will be described with reference to FIG. FIG. 21 is a cross-sectional view showing the ink droplet ejection operation of the inkjet recording head according to the third embodiment.

As shown in FIG. 21, the ink jet recording head 30 is connected to the external power source 80. An external power source 80 is provided on the upper surface portion 35a which is the positive electrode of the piezoelectric element 35.
Of the external power supply 80 is connected to the diaphragm 36. Bottom part 3 which is the negative electrode of the piezoelectric element 35
5b and the vibration plate 36 (the projections 36a and 36b thereof)
Since and are bonded to the conductive adhesive layers 37 and 37 ′, the diaphragm 36 is a negative electrode and is normally grounded by the external power supply 80.

A voltage is applied from the external power supply 80 between the upper surface portion 35a (positive electrode) of the piezoelectric element 35 and the vibration plate 36 (negative electrode). The voltage applied by the external power supply 80 is preferably less than 40 (V), for example, 30 (V), as in the first embodiment.

Here, the ink jet recording head 30 shown in FIG. 19 is in a state in which no voltage is applied by the external power source 80, and this state is called a stationary state. In addition, the inkjet recording head 30 shown in FIG.
Is a state in which a voltage is applied by the external power supply 80,
This state is called an operating state.

First, in a stationary state, as a voltage application to the piezoelectric element 35, a voltage is applied between the upper surface portion 35a (positive electrode) of the piezoelectric element 35 and the vibration plate 36 (negative electrode) by the external power supply 80. At this time, the piezoelectric element 35 contracts in the directions of the arrows a and b (contracting operation), and the piezoelectric element 35 adhesive surface of the vibration plate 36 is in-plane via the adhesive layers 37 and 37 'and the protrusions 36a and 36b. Compress in the direction. As a result, the diaphragm 3
The bending moment M acts on the vibrating plate 6, and the vibrating plate 36 bends and deforms in the Y2 direction (flexing deformation operation).
As a result, the inkjet recording head 30 shifts to the operating state.

In the contraction operation of the piezoelectric element 35, the piezoelectric element 3
5 contracts from one of both ends of the piezoelectric element 35 in the direction of the arrow a parallel to the X2 direction toward the axis L, and from the other of both ends of the piezoelectric element 35 parallel to the X1 direction toward the axis L. Contract in the direction of the arrow b.

Next, in the operating state, in the pressure chamber 2,
Bending deformation operation of the diaphragm 36 (when the upper surface portion 2b of the pressure chamber 2 is Y
The ink 11 in the pressure chamber 2 is compressed by the volume displacement due to the bending in two directions). As a result, the inkjet recording head 30 can eject the ink 11 as the ink droplet 12 from the nozzle 1 communicating with the pressure chamber 2.

Next, in the operating state, the external power source 80
Thus, the voltage applied between the upper surface portion 35a (positive electrode) of the piezoelectric element 35 and the vibrating plate 36 (negative electrode) is reduced to 0.
When set to (V) (when the voltage applied to the piezoelectric element 35 is returned to the original value), the inkjet recording head 30 shifts to the stationary state, and the piezoelectric element 35 and the diaphragm 36 return to the original state shown in FIG. Return (deflection end operation). In the pressure chamber 2, due to the restoring force (capillary force) of the meniscus of the ink formed in the nozzle 1, the ink 13 in the ink pool 4 is supplied / supplied into the pressure chamber 2 through the supply port 3. .

In this way, the ink jet recording head 3
At 0, the piezoelectric element 35 and the vibration plate 36 have the adhesive layers 37, 3 and 3.
Since it is partially bonded by 7 ', the piezoelectric element 35
The vibrating plate 36 and the vibrating plate 36 can have different curvatures, so that the vibrating plate 36 can be largely bent without the piezoelectric element 35 itself being greatly bent.

As described above, according to the ink jet recording head 30 according to the third embodiment, the same effect as that of the first embodiment can be obtained.

The ink jet recording head 30 according to the third embodiment is not limited to the above description. An adhesive layer (including an adhesive layer 37 and an adhesive layer 37 '),
The protrusion (including the protrusion 36a and the protrusion 36b) is not limited to the shape shown in FIG. 20, and as shown in FIG. 22, has a predetermined position along the circumference of the circle of the piezoelectric element 35. Is preferably provided in the. Furthermore, an adhesive layer (including the adhesive layer 37 and the adhesive layer 37 ′), (protrusion 36 a and protrusion 3
6b) and a radius (s) around the axis L.
It is preferable that the shape is partially formed on the circumference of 1 + t1 × (1/2)) at a predetermined distance, for example, at an interval of 45 degrees around the axis L. . In this case, the above-mentioned adhesive layer 3
7 and the adhesive layer 37 'are preferably formed separately from each other. It is preferable that the protrusion 36a and the protrusion 36b described above are formed separately from each other.

Further, the piezoelectric element 35 shown in FIG.
The shape is not limited to the circular shape, and may be a square shape as shown in FIG. In this case, the piezoelectric element 35 having a square shape has lengths W of four sides and 2
The intersection of the diagonal lines of the book is provided so as to correspond to the axis L,
It is preferable that two of the four sides are provided parallel to the X1 direction (or the X2 direction). In addition, an adhesive layer (including the adhesive layer 37 and the adhesive layer 37 ′), a protrusion 36 a and a protrusion 3
The protrusions (including 6 b) are preferably provided along at least two of the four sides of the square of the piezoelectric element 35. Further, an adhesive layer (including an adhesive layer 37 and an adhesive layer 37 '), (including a protrusion 36a and a protrusion 36b)
The protrusion has a length of each of four sides (s1 + t1 + s2 +
t2), the intersections of the two diagonal lines are provided so as to correspond to the axis L, and two of the four sides are in the X1 direction (or X).
From a square provided in parallel with (2 directions), each of the four sides has a length (s1 + s2), and the intersections of the two diagonals are provided so as to correspond to the axis L. Is X
It is preferable that the shape is formed in a portion (area) other than a square provided parallel to one direction (or X2 direction). Further, it is preferable that the adhesive layer 37 and the adhesive layer 37 ′ described above are integrally formed. It is preferable that the protrusion 36a and the protrusion 36b are integrally formed.

When the piezoelectric element 35 shown in FIG. 23 has a square shape, an adhesive layer (including an adhesive layer 37 and an adhesive layer 37 '), (including a protrusion 36a and a protrusion 36b).
The protrusions are preferably provided at predetermined positions along at least two sides of the four sides of the square of the piezoelectric element 35. Furthermore, the adhesive layer (including the adhesive layer 37 and the adhesive layer 37 ') and the protrusion (including the protrusions 36a and 36b) are not limited to the shape shown in FIG. As shown, it is preferable that the shape is partially formed at a predetermined distance, for example, at an interval of 45 degrees around the axis L. In this case, it is preferable that the adhesive layer 37 and the adhesive layer 37 ′ described above be formed apart from each other. The above-mentioned protrusion 36
It is preferable that the a and the protrusion 36b are formed apart from each other.

In addition, the piezoelectric element 35 shown in FIG.
The shape is not limited to a square shape, and may be a rectangular shape as shown in FIG. In this case, in the rectangular piezoelectric element 35, two sides out of the four sides are longer than the two sides having the length W, and two sides out of the four sides having the length W are X.
It is preferably provided in parallel to one direction (or X2 direction). The adhesive layer (including the adhesive layer 37 and the adhesive layer 37 ′) and the protrusion (including the protrusion 36 a and the protrusion 36 b) have the length W of the four sides of the rectangle of the piezoelectric element 35. It is preferably provided along two sides longer than the two sides. Furthermore, it is preferable that the adhesive layer 37 and the adhesive layer 37 ′ described above and the protrusions 36a and 36b be formed so as to extend in the vertical direction on the same plane in the X1 direction. In this case, it is preferable that the adhesive layer 37 and the adhesive layer 37 ′ described above be formed apart from each other. The above-mentioned protrusion 36
It is preferable that the a and the protrusion 36b are formed apart from each other.

Further, the shapes of the pressure chamber 2 and the ink pool 4 shown in FIG. 20 are not limited to the quadrangular truncated pyramid as shown in FIG. 26, and may be a truncated cone. In this case, the side surface portion 2c
And the side surface portion 2d are integrally formed, and the side surface portion 4c and the side surface portion 4 are formed.
It is preferable that d is integrally formed. Further, the piezoelectric element 35 is preferably a circle having a radius (W × (1/2)) centered on the axis L. In addition, an adhesive layer (including the adhesive layer 37 and the adhesive layer 37 ′), a protrusion 36 a and a protrusion 36
The protrusion (including b) is preferably provided along the circumference of the circle of the piezoelectric element 35. Furthermore, (adhesive layer 3
7 and the adhesive layer 37 '), and the protrusion (including the protrusion 36a and the protrusion 36b) is a radius centered on the axis L and having a radius (s1 + t1) centered on the axis L. The shape is preferably formed in a portion (area) excluding the circle of s1. In addition, the above-mentioned adhesive layer 37 and adhesive layer 3
7'is preferably integrally formed. It is preferable that the protrusion 36a and the protrusion 36b are integrally formed.

When the pressure chamber 2 and the ink pool 4 shown in FIG. 26 have a truncated cone shape, an adhesive layer (including an adhesive layer 37 and an adhesive layer 37 '), a protrusion 36a and a protrusion 36a are included. The protrusion (including 36 b) is not limited to the shape shown in FIG. 26, and is preferably provided at a predetermined position along the circumference of the circle of the piezoelectric element 35 as shown in FIG. 27. Further, the adhesive layer (including the adhesive layer 37 and the adhesive layer 37 ′) and the protrusion (including the protrusion 36a and the protrusion 36b) have a radius (s1 + t1 × (1 /
It is preferable that the shape is partially formed on the circumference of 2)) at a predetermined distance, for example, at intervals of 45 degrees around the axis L. In this case, it is preferable that the adhesive layer 37 and the adhesive layer 37 ′ described above be formed apart from each other. It is preferable that the protrusion 36a and the protrusion 36b described above are formed separately from each other.

Further, the ink jet recording head 30 according to the third embodiment is not limited to the piezoelectric element 35 as long as it is an element that presses the pressure chamber 2 via the vibration plate 36. Examples of the element that presses the pressure chamber 2 via the vibration plate 36 include an electrostrictive element, a magnetostrictive element, and a shape memory alloy. In this case, when any of the electrostrictive element, the magnetostrictive element, and the shape memory alloy is moved / driven in the a and b directions instead of the piezoelectric element 35, any of the electrostrictive element, the magnetostrictive element, and the shape memory alloy is
By pressing the pressure chamber 2 via the diaphragm 36,
It is preferable to change the pressure inside the pressure chamber 2 and eject the ink 11 from the nozzle 1 as an ink droplet.

(Embodiment 4) An ink jet recording head 40 according to Embodiment 4 will be described with reference to FIG. FIG. 28 is a sectional view showing the ink jet recording head according to the fourth embodiment.

As shown in FIG. 28, the ink jet recording head 40 includes a nozzle plate 9 and a plate 8.
A vibration plate 46 extending parallel to the nozzle plate 9, an adhesive layer 47, and a piezoelectric element 45. Here, in the fourth embodiment, description that overlaps with the first embodiment will be omitted.

A vibrating plate 46 is provided and connected on the plate 8 instead of the vibrating plate 6.

The diaphragm 46 is made of a metal material such as nickel or stainless. The diaphragm 4
6 is not limited to a metal material, and may be a resin exemplified by polyimide, or silicon may be used. in this case,
Nozzle plate 9, first plate 8a, and second plate 8
The combination of the materials used for b, the third plate 8c, and the diaphragm 46 may be the same or different in the above example. The optimum combination is selected as appropriate according to the requirements for designing the head.

Plate 8, nozzle plate 9 and diaphragm 4
Reference numeral 6 forms a pressure chamber 2 for containing and pressurizing ink, and the pressure chamber 2 is filled with ink 11. The upper surface portion 2b of the pressure chamber 2 is a surface in contact with the vibration plate 46. Here, the shape of the pressure chamber 2 is preferably a truncated pyramid (see FIG. 29). In this case, the side surface portion 2c and the side surface portion 2d are formed apart from each other. In addition, the pressure chamber 2 has a side surface 2
It is preferable to further include a side surface portion (not shown) that connects c with the side surface portion 2d.

Further, the plate 8, the nozzle plate 9 and the vibrating plate 46 form an ink pool 4 for accommodating ink and supplying / supplying it to the pressure chamber 2, and the ink pool 4 is filled with the ink 13. There is. The upper surface portion 4b of the ink pool 4 is a surface in contact with the vibration plate 46. Here, the shape of the ink pool 4 is preferably a truncated pyramid (FIG. 2).
9). In this case, the side surface portion 4c and the side surface portion 4d are formed apart from each other. In addition, the ink pool 4 includes the side surface portion 4
It is preferable to further have a side surface portion (not shown) that connects c with the side surface portion 4d.

The second plate 8b showing the plate 8 includes:
The ink pool 4 communicates with the pressure chamber 2, and the ink pool 4
A supply port 3 for replenishing / supplying the ink 13 accommodated in the pressure chamber 2 as the ink 11 is formed. Here, the upper surface portion 3c of the supply port 3 is a surface in contact with the vibration plate 46.

The nozzle plate 9 is formed with nozzles 1 which communicate with the pressure chamber 2 and eject the ink 11 as ink droplets. Here, the shape of the nozzle 1 is preferably a truncated cone (see FIG. 29). In this case, the side surface portion 1c and the side surface portion 1d are integrally formed.

The piezoelectric element 45 has a top surface portion 45a and a bottom surface portion 4
5b and side surface portions 45c and 45d. Piezoelectric element 45
The length W of the top surface portion 45a and the bottom surface portion 45b in the X1 direction is
It is the same as the length of the upper surface portion 2b of the pressure chamber 2 in the X1 direction.
The positive electrode is thinly formed on the upper surface portion 45a, the negative electrode is thinly formed on the bottom surface portion 45b, and the piezoelectric element 45 is polarized in advance by the polarization treatment. The pre-polarized piezoelectric element 45 is deformed based on the voltage applied between the top surface portion 45a and the bottom surface portion 45b.

Further, similarly to the first embodiment, as a polarization process, a positive voltage equal to or more than a set value is applied to the upper surface 45a which is a positive electrode and a negative voltage (usually ground) is applied to the bottom surface 45b which is a negative electrode. , The piezoelectric element 45 has a positive voltage applied to the upper surface 45a and a negative voltage applied to the bottom surface 45b (usually grounded).
Is driven so as to contract in the directions of arrows a and b.

The vibrating plate 46 is provided with projections 46a and 46b provided on the surface thereof. Protrusions 46a, 4
An adhesive layer 47 for partially joining the piezoelectric element 45 and the vibration plate 46 is provided on the 6b. Protrusion 46a
In the X1 direction which is the direction perpendicular to the axis L, the axis L
Is separated from the axis L by a distance s1.
It has a directional length t1. The protrusion 46b is provided at a distance s2 from the axis L in the X2 direction which is a direction perpendicular to the axis L, and has a length t2 in the X2 direction with respect to the axis L.
Have.

Here, the distance s1 is the same as the distance s2, and the length t1 of the protrusion 46a in the X1 direction with respect to the axis L.
Is the length t2 of the protrusion 46b in the X2 direction with respect to the axis L.
Is preferably the same as Also, length W, distance s
When the units of 1, s2 and lengths t1 and t2 are unified (for example, meters), (W / 2) ≧ (s1 + t1), s1 ≧
It is preferable that t1, (W / 2) ≧ (s2 + t2), and s2 ≧ t2. Further, the length of the adhesive layer 47 in the X1 direction (the total length of the adhesive layer 47 in the X1 direction with respect to the axis L and the length in the X2 direction with respect to the axis L) is (s
1 + t1 + s2 + t2) or more and preferably W or less.

The adhesive layer 47 is an adhesive material having excellent conductivity. An epoxy adhesive is exemplified as the adhesive material.

The piezoelectric element 45 is provided on the adhesive layer 47. The bottom surface portion 45 b of the piezoelectric element 45 has an adhesive layer 47.
Thus, the diaphragm 46 is partially joined.

Here, as shown in FIG. 29, when the piezoelectric element 45 has a circular shape, the piezoelectric element 45 and the adhesive layer 47 are formed.
Is preferably a circle having a radius (W × (1/2)) centered on the axis L. In this case, it is preferable that the protrusion (including the protrusion 46a and the protrusion 46b) is provided along the circumference of the circle of the piezoelectric element 45. Furthermore, the protrusion (including the protrusion 46a and the protrusion 46b) is the axis L
It is preferable that the shape is formed in a portion (area) excluding a circle having a radius s1 centered on the axis L from a circle having a radius (s1 + t1) centered at. It is preferable that the protrusion 46a and the protrusion 46b are integrally formed.

As shown in FIG. 28, when the piezoelectric element 45 is moved / driven in the in-plane direction (when contracted) in accordance with the voltage applied between the top surface portion 45a and the bottom surface portion 45b,
Since the piezoelectric element 45 and the vibration plate 46 are partially joined by the adhesive layer 47 via the protrusions 46a and 46b,
The surface of the vibrating plate 46 to which the piezoelectric element 45 is bonded is compressed in the in-plane direction. As a result, the bending moment M acts on the diaphragm 46, and the diaphragm 46 is flexibly deformed in the Y2 direction. At this time, since the piezoelectric element 45 and the vibration plate 46 are joined only by the adhesive layer 47 via the protrusions 46a and 46b, the vibration plate 6 is not affected by the bending rigidity of the piezoelectric element 5. The flexural deformation occurs according to the bending moment M acting on the diaphragm 6 according to its own bending rigidity. As a result, the inkjet recording head 40 can pressurize the ink 11 at a low voltage by significantly improving the volume displacement of the pressure chamber 2.

In the pressure chamber 2, the internal pressure changes (volume displacement) based on the movement / drive of the piezoelectric element 45 (deflection of the vibration plate 46). The ink droplets described above are ejected from the nozzle 1 based on the change in the pressure of the pressure chamber 2. Piezoelectric element 4
5 presses the pressure chamber 2 via the vibration plate 46 to eject the ink 11 from the nozzle 1 as an ink droplet. As described above, the ink jet recording head 40 enables the density and size of the pressure chamber 2 to be increased by significantly improving the volume displacement of the pressure chamber 2, and by applying the ink 11 at a low voltage. It enables low power consumption and low voltage of the head.

As described above, according to the ink jet recording head 40 of the fourth embodiment, the same effect as that of the first embodiment can be obtained.

Next, the ink droplet ejection operation of the ink jet recording head 40 will be described with reference to FIG. FIG. 30 is a cross-sectional view showing the ink droplet ejection operation of the inkjet recording head according to the fourth embodiment.

As shown in FIG. 30, the ink jet recording head 40 is connected to an external power source 80. An external power source 80 is provided on the upper surface portion 45a which is the positive electrode of the piezoelectric element 45.
Of the external power source 80 is connected to the diaphragm 46. Bottom part 4 which is the negative electrode of the piezoelectric element 45
5b and the vibration plate 46 (protrusions 46a, 46b) are bonded to the conductive adhesive layer 47, the vibration plate 4
Reference numeral 6 is a negative electrode, which is normally grounded by an external power supply 80.

A voltage is applied between the upper surface portion 45a (positive electrode) of the piezoelectric element 45 and the vibration plate 46 (negative electrode) by the external power supply 80. The voltage applied by the external power supply 80 is preferably less than 40 (V), for example, 30 (V), as in the first embodiment.

Here, the ink jet recording head 40 shown in FIG. 28 is in a state where no voltage is applied by the external power source 80, and this state is referred to as a stationary state. Further, the inkjet recording head 40 shown in FIG.
Is a state in which a voltage is applied by the external power supply 80,
This state is called an operating state.

First, in the stationary state, as a voltage application to the piezoelectric element 45, a voltage is applied between the upper surface portion 45a (positive electrode) of the piezoelectric element 45 and the vibration plate 46 (negative electrode) by the external power supply 80. At this time, the piezoelectric element 45 contracts in the directions of the arrows a and b (contraction operation), and the piezoelectric layer 45 moves from the adhesive layer 47 to the protrusion 4
The piezoelectric element 45 bonding surface of the vibration plate 46 is compressed in the in-plane direction via 6a and 46b. As a result, the bending moment M acts on the diaphragm 46, and the diaphragm 46 moves in the Y direction.
Flexural deformation occurs in two directions (flexural deformation operation). As a result, the inkjet recording head 40 shifts to the operating state.

When the piezoelectric element 45 contracts, the piezoelectric element 4
5 contracts from one of both ends of the piezoelectric element 45 in the direction of arrow a parallel to the X2 direction toward the axis L, and from the other of both ends of the piezoelectric element 45 parallel to the X1 direction toward the axis L. Contract in the direction of the arrow b.

Next, in the operating state, in the pressure chamber 2,
Bending deformation operation of the diaphragm 46 (when the upper surface 2b of the pressure chamber 2 is Y
The ink 11 in the pressure chamber 2 is compressed by the volume displacement due to the bending in two directions). As a result, the inkjet recording head 40 can eject the ink 11 as the ink droplet 12 from the nozzle 1 communicating with the pressure chamber 2.

Next, in the operating state, the external power source 80
As a result, the voltage applied between the upper surface portion 45a (positive electrode) of the piezoelectric element 45 and the vibration plate 46 (negative electrode) is reduced to zero.
When it is set to (V) (when the voltage applied to the piezoelectric element 45 is returned to the original), the inkjet recording head 40 shifts to the stationary state, and the piezoelectric element 45 and the vibration plate 46 return to the original state shown in FIG. 28. Return (deflection end operation). In the pressure chamber 2, due to the restoring force (capillary force) of the meniscus of the ink formed in the nozzle 1, the ink 13 in the ink pool 4 is supplied / supplied into the pressure chamber 2 through the supply port 3. .

In this way, the ink jet recording head 4
At 0, since the piezoelectric element 45 and the vibration plate 46 are partially bonded by the adhesive layer 47, the piezoelectric element 45 and the vibration plate 46 can have different curvatures, and the piezoelectric element 4
It is possible for the vibration plate 46 to be largely bent without itself being greatly bent.

The ink jet recording head 40 according to the fourth embodiment is not limited to the above description. The protrusion (including the protrusion 46a and the protrusion 46b) is not limited to the shape shown in FIG. 29, and as shown in FIG. 31, has a predetermined position along the circumference of the circle of the piezoelectric element 45. Is preferably provided in the. Furthermore, (protrusion 46
The protrusions (including a and the protrusions 46b) are provided on a circumference of a radius (s1 + t1 × (1/2)) centered on the axis L at a predetermined distance, for example, at an interval of 45 degrees about the axis L. It is preferably a partially formed shape. . In this case, it is preferable that the above-mentioned protrusion 46a and protrusion 46b be formed apart from each other.

The piezoelectric element 45 and the adhesive layer 47 shown in FIG. 31 are not limited to the circular shape, and may be a square shape as shown in FIG. in this case,
The square piezoelectric element 45 and the adhesive layer 47 each have a length W of four sides and are provided so that the intersections of two diagonal lines correspond to the axis L, and two of the four sides are It is preferably provided in parallel with the X1 direction (or the X2 direction).
The protrusion (including the protrusion 46 a and the protrusion 46 b) is at least two of the four sides of the square of the piezoelectric element 45.
It is preferably provided along the side. Furthermore,
The protrusion (including the protrusion 46a and the protrusion 46b) has four protrusions.
Each side has a length (s1 + t1 + s2 + t2), and the intersections of the two diagonal lines are provided so as to correspond to the axis L. Two of the four sides are provided parallel to the X1 direction (or the X2 direction). From the square, the length of each of the four sides (s
1 + s2), and the intersections of the two diagonal lines are provided so as to correspond to the axis L, and two of the four sides except for the square provided parallel to the X1 direction (or the X2 direction) ( The shape is preferably formed in a region. Further, it is preferable that the above-mentioned protrusion 46a and protrusion 46b are integrally formed.

When the piezoelectric element 45 and the adhesive layer 47 shown in FIG. 32 have a square shape, the protrusion (including the protrusion 46a and the protrusion 46b) has four sides of the square of the piezoelectric element 45. It is preferable to be provided at a predetermined position along at least two sides of the above. Furthermore, the protrusion (including the protrusion 46a and the protrusion 46b) is not limited to the shape shown in FIG. 32, and as shown in FIG.
For example, it is preferable that the shape is partially formed at intervals of 45 degrees around the axis L. In this case, it is preferable that the above-mentioned protrusion 46a and protrusion 46b be formed apart from each other.

Further, the piezoelectric element 45 and the adhesive layer 47 shown in FIG. 32 are not limited to the square shape, and the piezoelectric element 45 and the adhesive layer 47 shown in FIG.
It may be rectangular as shown in FIG. In this case, in the rectangular piezoelectric element 45 and the adhesive layer 47, two sides out of the four sides are longer than the two sides having the length W, and two sides out of the four sides having the length W are in the X1 direction ( Alternatively, it is preferably provided parallel to the X2 direction). In addition, (protrusion 46
It is preferable that the protrusions (including a and the protrusions 46b) are provided along two longer sides than the two sides having the length W out of the four sides of the rectangle of the piezoelectric element 45. Further, it is preferable that the above-mentioned protrusions 46a and 46b are formed so as to extend in the vertical direction on the same plane in the X1 direction. In this case, it is preferable that the above-mentioned protrusion 46a and protrusion 46b be formed apart from each other.

The shapes of the pressure chamber 2 and the ink pool 4 shown in FIG. 29 are not limited to the truncated pyramids as shown in FIG. 35, and may be truncated cones. In this case, the side surface portion 2c
And the side surface portion 2d are integrally formed, and the side surface portion 4c and the side surface portion 4 are formed.
It is preferable that d is integrally formed. Further, the piezoelectric element 45 and the adhesive layer 47 have a radius (W ×
A circle of (1/2)) is preferable. Further, it is preferable that the protrusion (including the protrusion 46 a and the protrusion 46 b) is provided along the circumference of the circle of the piezoelectric element 45. Furthermore, (including the protrusion 46a and the protrusion 46b)
It is preferable that the protrusion has a shape formed in a portion (area) excluding a circle having a radius (s1 + t1) centered on the axis L and having a radius s1 centered on the axis L. Further, it is preferable that the above-mentioned protrusion 46a and protrusion 46b are integrally formed.

When the pressure chamber 2 and the ink pool 4 shown in FIG. 35 are frustoconical, the protrusions (including the protrusions 46a and 46b) have the shapes shown in FIG. However, as shown in FIG. 36, the piezoelectric element 4
It is preferably provided at a predetermined position along the circumference of the circle of 5. Furthermore, the protrusion (including the protrusion 46a and the protrusion 46b) has a radius (s1 + t1 ×) centered on the axis L.
It is preferable that the shape is partially formed on the circumference of (1/2) at a predetermined distance, for example, at an interval of 45 degrees around the axis L. In this case, it is preferable that the above-mentioned protrusion 46a and protrusion 46b be formed apart from each other.

The ink jet recording head 40 according to the fourth embodiment is not limited to the piezoelectric element 45 as long as it is an element that presses the pressure chamber 2 via the vibration plate 46. Examples of the element that presses the pressure chamber 2 via the vibration plate 46 include an electrostrictive element, a magnetostrictive element, and a shape memory alloy. In this case, when any of the electrostrictive element, the magnetostrictive element, and the shape memory alloy moves / drives in the a and b directions instead of the piezoelectric element 45, any of the electrostrictive element, the magnetostrictive element, and the shape memory alloy,
By pressing the pressure chamber 2 via the vibration plate 46,
It is preferable to change the pressure inside the pressure chamber 2 and eject the ink 11 from the nozzle 1 as an ink droplet.

(Fifth Embodiment) An ink jet recording head 50 according to the fifth embodiment will be described with reference to FIG. FIG. 37 is a sectional view showing the ink jet recording head according to the fifth embodiment.

As shown in FIG. 37, the ink jet recording head 50 includes a nozzle plate 9 and a plate 8.
A vibration plate 56 extending parallel to the nozzle plate 9, adhesive layers 57 and 57 ', and a piezoelectric element 55. Here, in the fifth embodiment, description that overlaps with the first embodiment will be omitted.

On the plate 8, a diaphragm 56 is provided and connected instead of the diaphragm 6.

The diaphragm 56 is made of a metal material such as nickel or stainless. The diaphragm 5
6 is not limited to a metal material, and may be a resin exemplified by polyimide, or silicon may be used. in this case,
Nozzle plate 9, first plate 8a, and second plate 8
In the above example, the combination of materials used for b, the third plate 8c, and the diaphragm 56 may be arbitrary or the same. The optimum combination is selected as appropriate according to the requirements for designing the head.

Plate 8, nozzle plate 9 and diaphragm 5
Reference numeral 6 forms a pressure chamber 2 for containing and pressurizing ink, and the pressure chamber 2 is filled with ink 11. The upper surface portion 2b of the pressure chamber 2 is a surface in contact with the vibration plate 56. Here, the shape of the pressure chamber 2 is preferably a truncated pyramid (see FIG. 38). In this case, the side surface portion 2c and the side surface portion 2d are formed apart from each other. In addition, the pressure chamber 2 has a side surface 2
It is preferable to further include a side surface portion (not shown) that connects c with the side surface portion 2d.

Further, the plate 8, the nozzle plate 9 and the vibrating plate 56 form an ink pool 4 for accommodating the ink and supplying / supplying it to the pressure chamber 2, and the ink pool 4 is filled with the ink 13. There is. The upper surface portion 4b of the ink pool 4 is a surface in contact with the vibration plate 56. Here, the shape of the ink pool 4 is preferably a truncated pyramid (FIG. 3).
8). In this case, the side surface portion 4c and the side surface portion 4d are formed apart from each other. In addition, the ink pool 4 includes the side surface portion 4
It is preferable to further have a side surface portion (not shown) that connects c with the side surface portion 4d.

The second plate 8b showing the plate 8 includes:
The ink pool 4 communicates with the pressure chamber 2, and the ink pool 4
A supply port 3 for replenishing / supplying the ink 13 accommodated in the pressure chamber 2 as the ink 11 is formed. Here, the upper surface portion 3c of the supply port 3 is a surface in contact with the vibration plate 56.

The nozzle plate 9 is formed with nozzles 1 which communicate with the pressure chamber 2 and discharge the ink 11 as ink droplets. Here, it is preferable that the shape of the nozzle 1 is a truncated cone (see FIG. 38). In this case, the side surface portion 1c and the side surface portion 1d are integrally formed.

The piezoelectric element 55 has a top surface 55a and a bottom surface 5a.
5b, side surfaces 55c and 55d, protrusion 55e, and protrusion 5
5f and. The length W of the top surface portion 55a and the bottom surface portion 55b of the piezoelectric element 55 in the X1 direction is the same as the length of the top surface portion 2b of the pressure chamber 2 in the X1 direction. The positive electrode is thinly formed on the upper surface 55a, the negative electrode is thinly formed on the bottom surface 55b, and the piezoelectric element 55 is polarized in advance by the polarization process. The pre-polarized piezoelectric element 55 is deformed based on the voltage applied between the top surface portion 55a and the bottom surface portion 55b.

Further, similarly to the first embodiment, as a polarization process, a positive voltage equal to or more than a set value is applied to the upper surface 55a, which is a positive electrode, and a negative voltage (usually ground) is applied to the bottom 55b, which is a negative electrode. , The piezoelectric element 55 has a positive voltage applied to the top surface 55a and a negative voltage applied to the bottom surface 55b (usually grounded).
Is driven so as to contract in the directions of arrows a and b.

On the vibrating plate 56, adhesive layers 57 and 57 'for partially joining the piezoelectric element 55 and the vibrating plate 56 are provided. The adhesive layer 57 is provided at a distance s1 from the axis L in the X1 direction that is a direction perpendicular to the axis L, and has a length t1 in the X1 direction with respect to the axis L. The adhesive layer 57 ′ is provided at a distance s2 from the axis L in the X2 direction which is a direction perpendicular to the axis L, and has a length t2 in the X2 direction with respect to the axis L.

Here, the distance s1 is the same as the distance s2, and the length t1 of the adhesive layer 57 in the X1 direction with respect to the axis L.
Is the length t2 of the adhesive layer 57 'in the X2 direction with respect to the axis L.
Is preferably the same as Also, length W, distance s
When the units of 1, s2 and lengths t1 and t2 are unified (for example, meters), (W / 2) ≧ (s1 + t1), s1 ≧
It is preferable that t1, (W / 2) ≧ (s2 + t2), and s2 ≧ t2.

The adhesive layers 57 and 57 'are adhesive materials having excellent conductivity. An epoxy adhesive is exemplified as the adhesive material.

The piezoelectric element 55 is formed on the adhesive layers 57 and 57 '.
Is provided. On the bottom surface 55b of the piezoelectric element 55,
The protrusion 55e and the protrusion 55 provided on the bottom surface 55b
f and are formed. Projection 55e and projection 55f
Acts as a negative electrode similarly to the bottom surface portion 55b. Protrusion 5
5e is bonded on the adhesive layer 57, and the protrusion 55f is bonded on the adhesive layer 57 '. Bottom surface portion 55 of piezoelectric element 55
b is partially joined to the diaphragm 56 by the adhesive layers 57 and 57 '. The protrusion 55e is provided at a distance s1 from the axis L in the X1 direction which is a direction perpendicular to the axis L, and has a length t1 in the X1 direction with respect to the axis L.
The protrusion 55f is provided at a distance s2 from the axis L in the X2 direction which is a direction perpendicular to the axis L, and
Has a length t2 in the X2 direction.

Here, as shown in FIG. 38, when the piezoelectric element 55 has a circular shape, the piezoelectric element 55 has a radius (W × (1/2)) centered on the axis L. Is preferred. In this case, an adhesive layer (including an adhesive layer 57 and an adhesive layer 57 '), (including a protrusion 55e and a protrusion 55f)
The protrusions are preferably provided along the circumference of the circle of the piezoelectric element 55. Further, (the adhesive layer 57 and the adhesive layer 5
Adhesive layer (including 7 ') (projection 55e and projection 55f)
The projections (including and) have a radius (s1 +
It is preferable that the shape is formed in a portion (area) excluding the circle of radius s1 centered on the axis L from the circle of t1). It is preferable that the adhesive layer 57 and the adhesive layer 57 ′ described above are integrally formed. The above-mentioned protrusion 55e and protrusion 55f
Are preferably integrally formed.

As shown in FIG. 37, when the piezoelectric element 55 is moved / driven in the in-plane direction (when contracted) in accordance with the voltage applied between the top surface portion 55a and the bottom surface portion 55b,
Since the piezoelectric element 55 and the vibration plate 56 are partially bonded by the adhesive layers 57 and 57 'via the protrusions 55e and 55f, the piezoelectric element 55 bonding surface of the vibration plate 56 is compressed in the in-plane direction. . As a result, the bending moment M acts on the diaphragm 56, and the diaphragm 56 is flexibly deformed in the Y2 direction. At this time, the piezoelectric element 55 and the diaphragm 56
Is the adhesive layer 57, 57 'via the protrusions 55e, 55f.
Since the vibration plate 56 is bonded only to the piezoelectric element 5,
The flexural deformation occurs according to the bending moment M acting on the diaphragm 56 according to the bending rigidity of itself without being influenced by the bending rigidity of No. 5. As a result, the inkjet recording head 50 can pressurize the ink 11 at a low voltage by significantly improving the volume displacement of the pressure chamber 2.

In the pressure chamber 2, the internal pressure changes (volume displacement) based on the movement / drive of the piezoelectric element 55 (deflection of the diaphragm 56). The ink droplets described above are ejected from the nozzle 1 based on the change in the pressure of the pressure chamber 2. Piezoelectric element 5
5 presses the pressure chamber 2 via the vibration plate 56 to eject the ink 11 from the nozzle 1 as an ink droplet. In this way, the ink jet recording head 50 enables the density of the pressure chamber 2 to be increased and the size thereof to be reduced by significantly improving the volume displacement of the pressure chamber 2, and by applying the ink 11 at a low voltage. It enables low power consumption and low voltage of the head.

Next, the ink droplet ejection operation of the ink jet recording head 50 will be described with reference to FIG. FIG. 39 is a cross-sectional view showing the ink droplet ejection operation of the inkjet recording head according to the fifth embodiment.

As shown in FIG. 39, the ink jet recording head 50 is connected to the external power source 80. An external power source 80 is provided on the upper surface 55a, which is the positive electrode of the piezoelectric element 55.
Of the external power source 80 is connected to the diaphragm 56. Bottom part 5 which is the negative electrode of the piezoelectric element 55
5b (the projections 55e and 55f thereof) and the diaphragm 56
Since and are bonded to the conductive adhesive layers 57 and 57 ′, the diaphragm 56 is a negative electrode and is normally grounded by the external power supply 80.

A voltage is applied from the external power supply 80 between the upper surface 55a (positive electrode) of the piezoelectric element 55 and the diaphragm 56 (negative electrode). The voltage applied by the external power supply 80 is preferably less than 40 (V), for example, 30 (V), as in the first embodiment.

Here, the ink jet recording head 50 shown in FIG. 37 is in a state where no voltage is applied by the external power source 80, and this state is called a stationary state. In addition, the inkjet recording head 50 shown in FIG.
Is a state in which a voltage is applied by the external power supply 80,
This state is called an operating state.

First, in a stationary state, as a voltage application to the piezoelectric element 55, a voltage is applied between the upper surface 55a (positive electrode) of the piezoelectric element 55 and the diaphragm 56 (negative electrode) by the external power supply 80. At this time, the piezoelectric element 55 contracts in the directions of arrows a and b (contraction operation), and the piezoelectric element 55 adhesive surface of the diaphragm 56 is in-plane via the protrusions 55e and 55f and the adhesive layers 57 and 57 '. Compress in the direction. As a result, the diaphragm 5
The bending moment M acts on the vibrating plate 6, and the vibrating plate 56 undergoes flexural deformation in the Y2 direction (flexural deformation operation).
As a result, the inkjet recording head 50 shifts to the operating state.

In the contraction operation of the piezoelectric element 55, the piezoelectric element 5
5 contracts from one of both ends of the piezoelectric element 55 in the direction of arrow a parallel to the X2 direction toward the axis L, and from the other of both ends of the piezoelectric element 55 parallel to the X1 direction toward the axis L. Contract in the direction of the arrow b.

Next, in the operating state, in the pressure chamber 2,
The flexure deformation operation of the diaphragm 56 (the upper surface portion 2b of the pressure chamber 2 is Y
The ink 11 in the pressure chamber 2 is compressed by the volume displacement due to the bending in two directions). As a result, the ink jet recording head 50 can eject the ink 11 as the ink droplet 12 from the nozzle 1 communicating with the pressure chamber 2.

Next, in the operating state, the external power source 80
As a result, the voltage applied between the upper surface portion 55a (positive electrode) of the piezoelectric element 55 and the vibration plate 56 (negative electrode) is reduced to zero.
When set to (V) (when the voltage applied to the piezoelectric element 55 is returned to the original value), the inkjet recording head 50 shifts to the stationary state, and the piezoelectric element 55 and the diaphragm 56 return to the original state shown in FIG. Return (deflection end operation). In the pressure chamber 2, due to the restoring force (capillary force) of the meniscus of the ink formed in the nozzle 1, the ink 13 in the ink pool 4 is supplied / supplied into the pressure chamber 2 through the supply port 3. .

In this way, the ink jet recording head 5
At 0, the piezoelectric element 55 and the diaphragm 56 have the adhesive layers 57, 5 and 5.
Since it is partially bonded by 7 ', the piezoelectric element 55
The vibrating plate 56 and the vibrating plate 56 can have different curvatures, and the vibrating plate 56 can be largely bent without the piezoelectric element 55 itself being largely bent.

As described above, according to the ink jet recording head 50 of the fifth embodiment, the same effect as that of the first embodiment can be obtained.

The ink jet recording head 50 according to the fifth embodiment is not limited to the above description. An adhesive layer (including an adhesive layer 57 and an adhesive layer 57 '),
The protrusion (including the protrusion 55e and the protrusion 55f) is not limited to the shape shown in FIG. 38, and as shown in FIG. 40, has a predetermined position along the circumference of the circle of the piezoelectric element 55. Is preferably provided in the. Further, an adhesive layer (including the adhesive layer 57 and the adhesive layer 57 '), (the protrusion 55e and the protrusion 5)
The projections (including 5f) have a radius (s
It is preferable that the shape is partially formed on the circumference of 1 + t1 × (1/2)) at a predetermined distance, for example, at an interval of 45 degrees around the axis L. In this case, the above-mentioned adhesive layer 57
The adhesive layer 57 'and the adhesive layer 57' are preferably formed apart from each other. It is preferable that the protrusion 55e and the protrusion 55f described above are formed separately from each other.

Further, the piezoelectric element 55 shown in FIG.
The shape is not limited to the circular shape, and may be a square shape as shown in FIG. In this case, the piezoelectric element 55 having a square shape has lengths W of four sides and 2
The intersection of the diagonal lines of the book is provided so as to correspond to the axis L,
It is preferable that two of the four sides are provided parallel to the X1 direction (or the X2 direction). In addition, an adhesive layer (including the adhesive layer 57 and the adhesive layer 57 ′), a protrusion 55 e and a protrusion 5
The protrusions (including 5 f) are preferably provided along at least two of the four sides of the square of the piezoelectric element 55. Further, an adhesive layer (including an adhesive layer 57 and an adhesive layer 57 '), (including a protrusion 55e and a protrusion 55f)
The protrusion has a length of each of four sides (s1 + t1 + s2 +
t2), the intersections of the two diagonal lines are provided so as to correspond to the axis L, and two of the four sides are in the X1 direction (or X).
From a square provided in parallel with (2 directions), each of the four sides has a length (s1 + s2), and the intersections of the two diagonals are provided so as to correspond to the axis L. Is X
It is preferable that the shape is formed in a portion (area) other than a square provided parallel to one direction (or X2 direction). Further, it is preferable that the adhesive layer 57 and the adhesive layer 57 ′ described above are integrally formed. It is preferable that the protrusion 55e and the protrusion 55f are integrally formed.

When the piezoelectric element 55 shown in FIG. 41 has a square shape, an adhesive layer (including an adhesive layer 57 and an adhesive layer 57 '), (including a protrusion 55e and a protrusion 55f).
The protrusions are preferably provided at predetermined positions along at least two sides of the four sides of the square of the piezoelectric element 55. Furthermore, the adhesive layer (including the adhesive layer 57 and the adhesive layer 57 ′) and the protrusion (including the protrusion 55e and the protrusion 55f) are not limited to the shapes shown in FIG. As shown, it is preferable that the shape is partially formed at a predetermined distance, for example, at an interval of 45 degrees around the axis L. In this case, it is preferable that the adhesive layer 57 and the adhesive layer 57 ′ described above are formed apart from each other. The above-mentioned protrusion 55
It is preferable that the e and the protrusion 55f are formed apart from each other.

In addition, the piezoelectric element 55 shown in FIG.
The shape is not limited to a square shape, and may be a rectangular shape as shown in FIG. In this case, in the rectangular piezoelectric element 55, two sides out of the four sides are longer than the two sides having the length W, and two sides out of the four sides having the length W are X.
It is preferably provided in parallel to one direction (or X2 direction). The adhesive layer (including the adhesive layer 57 and the adhesive layer 57 ′) and the protrusion (including the protrusion 55 e and the protrusion 55 f) have a length W of the four sides of the rectangle of the piezoelectric element 55. It is preferably provided along two sides longer than the two sides. Furthermore, it is preferable that the adhesive layer 57 and the adhesive layer 57 ′ described above, and the protrusion 55e and the protrusion 55f described above are formed so as to extend in the vertical direction on the same plane in the X1 direction. In this case, it is preferable that the adhesive layer 57 and the adhesive layer 57 ′ described above are formed apart from each other. The above-mentioned protrusion 55
It is preferable that the e and the protrusion 55f are formed apart from each other.

The shapes of the pressure chamber 2 and the ink pool 4 shown in FIG. 38 are not limited to the truncated pyramids as shown in FIG. 44, and may be truncated cones. In this case, the side surface portion 2c
And the side surface portion 2d are integrally formed, and the side surface portion 4c and the side surface portion 4 are formed.
It is preferable that d is integrally formed. Further, the piezoelectric element 55 is preferably a circle having a radius (W × (1/2)) centered on the axis L. In addition, an adhesive layer (including the adhesive layer 57 and the adhesive layer 57 ′), a protrusion 55 e and a protrusion 55
The protrusion (including f) is preferably provided along the circumference of the circle of the piezoelectric element 55. Furthermore, (adhesive layer 5
7 and the adhesive layer 57 '), and the protrusion (including the protrusion 55e and the protrusion 55f) is a radius centered on the axis L and a radius (s1 + t1) centered on the axis L. The shape is preferably formed in a portion (area) excluding the circle of s1. In addition, the above-mentioned adhesive layer 57 and adhesive layer 5
7'is preferably integrally formed. It is preferable that the protrusion 55e and the protrusion 55f are integrally formed.

When the pressure chamber 2 and the ink pool 4 shown in FIG. 44 have a truncated cone shape, an adhesive layer (including an adhesive layer 57 and an adhesive layer 57 '), a protrusion 55e and a protrusion 55e. The protrusions (including 55f) are not limited to the shapes shown in FIG. 44, and are preferably provided at predetermined positions along the circumference of the circle of the piezoelectric element 55 as shown in FIG. Further, the adhesive layer (including the adhesive layer 57 and the adhesive layer 57 ′) and the protrusion (including the protrusion 55e and the protrusion 55f) have a radius (s1 + t1 × (1 /
The shape may be partially formed on the circumference of 2)) at a predetermined distance, for example, at an interval of 45 degrees around the axis L. In this case, it is preferable that the adhesive layer 57 and the adhesive layer 57 ′ described above are formed apart from each other. The above-mentioned protrusion 55
It is preferable that the e and the protrusion 55f are formed apart from each other.

Further, the ink jet recording head 50 according to the fifth embodiment is not limited to the piezoelectric element 55 as long as it is an element that presses the pressure chamber 2 via the vibration plate 56. Examples of the element that presses the pressure chamber 2 via the diaphragm 56 include an electrostrictive element, a magnetostrictive element, and a shape memory alloy. In this case, when any of the electrostrictive element, the magnetostrictive element, and the shape memory alloy moves / drives in the a and b directions instead of the piezoelectric element 55, any of the electrostrictive element, the magnetostrictive element, and the shape memory alloy,
By pressing the pressure chamber 2 via the diaphragm 56,
It is preferable to change the pressure inside the pressure chamber 2 and eject the ink 11 from the nozzle 1 as an ink droplet.

(Sixth Embodiment) An ink jet recording head 60 according to the sixth embodiment will be described with reference to FIG. FIG. 46 is a sectional view showing the ink jet recording head according to the sixth embodiment.

As shown in FIG. 46, the ink jet recording head 60 includes a nozzle plate 9 and a plate 8.
A vibration plate 66 extending parallel to the nozzle plate 9, an adhesive layer 67, and a piezoelectric element 65. Here, in the sixth embodiment, description that overlaps with the first embodiment will be omitted.

A vibrating plate 66 is provided and connected on the plate 8 instead of the vibrating plate 6.

The diaphragm 66 is made of a metal material such as nickel or stainless steel. The diaphragm 6
6 is not limited to a metal material, and may be a resin exemplified by polyimide, or silicon may be used. in this case,
Nozzle plate 9, first plate 8a, and second plate 8
In the above example, the combination of materials used for b, the third plate 8c, and the diaphragm 66 may be free or the same. The optimum combination is selected as appropriate according to the requirements for designing the head.

Plate 8, nozzle plate 9 and diaphragm 6
Reference numeral 6 forms a pressure chamber 2 for containing and pressurizing ink, and the pressure chamber 2 is filled with ink 11. The upper surface portion 2b of the pressure chamber 2 is a surface in contact with the vibration plate 66. Here, the shape of the pressure chamber 2 is preferably a truncated pyramid (see FIG. 47). In this case, the side surface portion 2c and the side surface portion 2d are formed apart from each other. In addition, the pressure chamber 2 has a side surface 2
It is preferable to further include a side surface portion (not shown) that connects c with the side surface portion 2d.

Further, the plate 8, the nozzle plate 9 and the vibrating plate 66 form an ink pool 4 for accommodating ink and supplying / supplying the ink to the pressure chamber 2, and the ink pool 4 is filled with the ink 13. There is. The upper surface portion 4b of the ink pool 4 is a surface in contact with the vibration plate 66. Here, the shape of the ink pool 4 is preferably a truncated pyramid (FIG. 4).
7). In this case, the side surface portion 4c and the side surface portion 4d are formed apart from each other. In addition, the ink pool 4 includes the side surface portion 4
It is preferable to further have a side surface portion (not shown) that connects c with the side surface portion 4d.

The second plate 8b showing the plate 8 includes:
The ink pool 4 communicates with the pressure chamber 2, and the ink pool 4
A supply port 3 for replenishing / supplying the ink 13 accommodated in the pressure chamber 2 as the ink 11 is formed. Here, the upper surface portion 3c of the supply port 3 is a surface in contact with the vibration plate 66.

The nozzle plate 9 is formed with nozzles 1 which communicate with the pressure chamber 2 and eject the ink 11 as ink droplets. Here, the shape of the nozzle 1 is preferably a truncated cone (see FIG. 47). In this case, the side surface portion 1c and the side surface portion 1d are integrally formed.

The piezoelectric element 65 has a top surface portion 65a and a bottom surface portion 6a.
5b, side surface portions 65c and 65d, and protruding portions 65e and 65f. The upper surface portion 65a and the bottom surface portion 65b of the piezoelectric element 65
The length W in the X1 direction of is the same as the length in the X1 direction of the upper surface portion 2b of the pressure chamber 2. The positive electrode is thinly formed on the upper surface portion 65a, the negative electrode is thinly formed on the bottom surface portion 65b, and the piezoelectric element 65 is polarized in advance by the polarization treatment. This pre-polarized piezoelectric element 65 has an upper surface portion 65
It deforms based on the voltage applied between a and the bottom portion 65b.

Further, similarly to the first embodiment, as a polarization process, a positive voltage higher than a set value is applied to the upper surface 65a which is a positive electrode, and a negative voltage (usually ground) is applied to the bottom surface 65b which is a negative electrode. , The piezoelectric element 65 has a positive voltage applied to the upper surface portion 65a and a negative voltage applied to the bottom surface portion 65b (usually grounded).
Is driven so as to contract in the directions of arrows a and b.

On the vibration plate 66, an adhesive layer 67 for partially joining the piezoelectric element 65 and the vibration plate 66 is provided.

The piezoelectric element 65 is provided on the adhesive layer 67. The bottom surface portion 65b of the piezoelectric element 65 has a bottom surface portion 6
Protrusions 65e and 65f provided on 5b are formed. The protrusion 65e and the protrusion 65f are the bottom face 65b.
It also works as a negative electrode. The protrusions 65e and 65f are bonded onto the adhesive layer 67. Bottom surface portion 6 of the piezoelectric element 65
5b is partially joined to the diaphragm 66 by the adhesive layer 67. The protrusion 65e is provided at a distance s1 from the axis L in the X1 direction which is a direction perpendicular to the axis L, and has a length t1 in the X1 direction with respect to the axis L. The protrusion 65f is provided at a distance s2 from the axis L in the X2 direction which is a direction perpendicular to the axis L, and has a length t2 in the X2 direction with respect to the axis L.

Here, the distance s1 is the same as the distance s2, and the length t1 of the protrusion 65e in the X1 direction with respect to the axis L.
Is the length t2 of the protrusion 65f in the X2 direction with respect to the axis L.
Is preferably the same as Also, length W, distance s
When the units of 1, s2 and lengths t1 and t2 are unified (for example, meters), (W / 2) ≧ (s1 + t1), s1 ≧
It is preferable that t1, (W / 2) ≧ (s2 + t2), and s2 ≧ t2. The length of the adhesive layer 67 in the X1 direction (the total length of the adhesive layer 67 in the X1 direction with respect to the axis L and the length in the X2 direction with respect to the axis L) is (s
1 + t1 + s2 + t2) or more and preferably W or less.

The adhesive layer 67 is an adhesive material having excellent conductivity. An epoxy adhesive is exemplified as the adhesive material.

Here, as shown in FIG. 47, when the piezoelectric element 65 has a circular shape, the piezoelectric element 65 and the adhesive layer 67 are formed.
Is preferably a circle having a radius (W × (1/2)) centered on the axis L. In this case, it is preferable that the protrusion (including the protrusion 65e and the protrusion 65f) be provided along the circumference of the circle of the piezoelectric element 65. Furthermore, the protrusion (including the protrusion 65e and the protrusion 65f) is the axis L
It is preferable that the shape is formed in a portion (area) excluding a circle having a radius s1 centered on the axis L from a circle having a radius (s1 + t1) centered at. It is preferable that the protrusion 65e and the protrusion 65f are integrally formed.

The piezoelectric element 65 has a top surface portion 65a and a bottom surface portion 65.
When the piezoelectric element 65 and the vibration plate 66 are moved / driven (flexed) in the Y2 direction according to the voltage applied between the piezoelectric element 65 and the vibration plate 66,
Is partially bonded by the adhesive layer 67, so that it bends about the protrusions 65e and 65f so as to have a curvature. As a result, the inkjet recording head 6
0 significantly pressurizes the ink 11 with a low voltage by significantly improving the volume displacement of the pressure chamber 2.

As shown in FIG. 46, when the piezoelectric element 65 is moved / driven (when contracted) in the in-plane direction in accordance with the voltage applied between the top surface portion 65a and the bottom surface portion 65b,
Since the piezoelectric element 65 and the vibration plate 66 are partially joined by the adhesive layer 67 via the protrusions 65e and 65f,
The surface of the vibrating plate 66 to which the piezoelectric element 65 is bonded is compressed in the in-plane direction. As a result, the bending moment M acts on the diaphragm 66, and the diaphragm 56 is flexibly deformed in the Y2 direction. At this time, since the piezoelectric element 65 and the vibrating plate 66 are joined only by the adhesive layer 67 via the protrusions 65e and 65f, the vibrating plate 66 is not affected by the bending rigidity of the piezoelectric element 65. The diaphragm 66 according to its own bending rigidity
Flexural deformation occurs in accordance with the bending moment M acting on. As a result, the inkjet recording head 60 can pressurize the ink 11 at a low voltage by significantly improving the volume displacement of the pressure chamber 2.

In the pressure chamber 2, the internal pressure changes (volume displacement) based on the movement / drive of the piezoelectric element 65 (deflection of the vibrating plate 66). The ink droplets described above are ejected from the nozzle 1 based on the change in the pressure of the pressure chamber 2. Piezoelectric element 6
5 presses the pressure chamber 2 via the vibrating plate 66 to eject the ink 11 from the nozzle 1 as an ink droplet. In this way, the ink jet recording head 60 enables a high density and a small size in the arrangement of the pressure chambers 2 by significantly improving the volume displacement of the pressure chambers 2, and by pressurizing the ink 11 with a low voltage. It enables low power consumption and low voltage of the head.

Next, the ink droplet ejection operation of the ink jet recording head 60 will be described with reference to FIG. FIG. 48 is a cross-sectional view showing the ink droplet ejection operation of the inkjet recording head according to the sixth embodiment.

As shown in FIG. 48, the ink jet recording head 60 is connected to the external power source 80. An external power source 80 is provided on the upper surface portion 65a which is the positive electrode of the piezoelectric element 65.
Of the external power source 80 is connected to the diaphragm 66. Bottom part 6 which is the negative electrode of the piezoelectric element 65
5b (the protrusions 65e and 65f thereof) and the vibration plate 66.
Since and are bonded to the conductive adhesive layer 67, the diaphragm 66 is a negative electrode and is normally grounded by the external power supply 80.

A voltage is applied between the upper surface portion 65a (positive electrode) of the piezoelectric element 65 and the vibrating plate 66 (negative electrode) by the external power supply 80. The voltage applied by the external power supply 80 is preferably less than 40 (V), for example, 30 (V), as in the first embodiment.

Here, the ink jet recording head 60 shown in FIG. 46 is in a state where no voltage is applied by the external power source 80, and this state is called a stationary state. Further, the inkjet recording head 60 shown in FIG.
Is a state in which a voltage is applied by the external power supply 80,
This state is called an operating state.

First, in the stationary state, as a voltage application to the piezoelectric element 65, a voltage is applied between the upper surface portion 65a (positive electrode) of the piezoelectric element 65 and the vibration plate 66 (negative electrode) by the external power supply 80. At this time, the piezoelectric element 65 contracts in the directions of the arrows a and b (contracting operation), and compresses the piezoelectric element 65 bonding surface of the vibration plate 66 in the in-plane direction together with the adhesive layer 67 via the protrusions 65e and 65f. . As a result, the bending moment M acts on the vibration plate 66, and the vibration plate 66 causes bending deformation in the Y2 direction (flexing deformation operation). As a result, the inkjet recording head 60 shifts to the operating state.

When the piezoelectric element 65 contracts, the piezoelectric element 6
5 contracts from one of both ends of the piezoelectric element 65 in the direction of the arrow a parallel to the X2 direction toward the axis L, and from the other of both ends of the piezoelectric element 65 parallel to the X1 direction toward the axis L. Contract in the direction of the arrow b.

Next, in the operating state, in the pressure chamber 2,
Bending deformation operation of the diaphragm 66 (when the upper surface portion 2b of the pressure chamber 2 is Y
The ink 11 in the pressure chamber 2 is compressed by the volume displacement due to the bending in two directions). As a result, the inkjet recording head 60 can eject the ink 11 as the ink droplet 12 from the nozzle 1 communicating with the pressure chamber 2.

Next, in the operating state, the external power supply 80
As a result, the voltage applied between the upper surface portion 65a (positive electrode) of the piezoelectric element 65 and the vibration plate 66 (negative electrode) is reduced to 0.
When the voltage is set to (V) (when the voltage applied to the piezoelectric element 65 is returned to the original value), the inkjet recording head 60 shifts to the stationary state, and the piezoelectric element 65 and the diaphragm 66 return to the original state shown in FIG. Return (deflection end operation). In the pressure chamber 2, due to the restoring force (capillary force) of the meniscus of the ink formed in the nozzle 1, the ink 13 in the ink pool 4 is supplied / supplied into the pressure chamber 2 through the supply port 3. .

In this way, the ink jet recording head 6
At 0, since the piezoelectric element 65 and the vibration plate 66 are partially bonded by the adhesive layer 67, the piezoelectric element 65 and the vibration plate 66 can have different curvatures, and the piezoelectric element 6
It is possible for the diaphragm 5 to largely bend without itself bending so much.

As described above, according to the ink jet recording head 60 of the sixth embodiment, the same effect as that of the first embodiment can be obtained.

The ink jet recording head 60 according to the sixth embodiment is not limited to the above description. The protrusion (including the protrusion 65e and the protrusion 65f) is not limited to the shape shown in FIG. 47, and as shown in FIG. 49, has a predetermined position along the circumference of the circle of the piezoelectric element 65. Is preferably provided in the. Furthermore, (protrusion 65
The protrusions (including e and the protrusions 65f) are arranged on a circumference of a radius (s1 + t1 × (1/2)) centered on the axis L at a predetermined distance, for example, at intervals of 45 degrees about the axis L. It is preferably a partially formed shape. In this case, it is preferable that the protrusion 65e and the protrusion 65f described above be formed apart from each other.

The piezoelectric element 65 and the adhesive layer 67 shown in FIG. 49 are not limited to the circular shape, and may be a square shape as shown in FIG. in this case,
The square piezoelectric element 65 and the adhesive layer 67 have respective lengths W of four sides, are provided so that the intersections of the two diagonals correspond to the axis L, and two of the four sides are It is preferably provided in parallel with the X1 direction (or the X2 direction).
Further, the protrusion (including the protrusion 65 e and the protrusion 65 f) is at least two of the four sides of the square of the piezoelectric element 65.
It is preferably provided along the side. Furthermore,
The protrusion (including the protrusion 65e and the protrusion 65f) has 4
Each side has a length (s1 + t1 + s2 + t2), and the intersections of the two diagonal lines are provided so as to correspond to the axis L. Two of the four sides are provided parallel to the X1 direction (or the X2 direction). From the square, the length of each of the four sides (s
1 + s2), and the intersections of the two diagonal lines are provided so as to correspond to the axis L, and two of the four sides except for the square provided parallel to the X1 direction (or the X2 direction) ( The shape is preferably formed in a region. In addition, it is preferable that the above-mentioned protrusions 65e and 65f are integrally formed.

When the piezoelectric element 65 and the adhesive layer 67 shown in FIG. 50 have a square shape, the protrusion (including the protrusion 65e and the protrusion 65f) has four sides of the square of the piezoelectric element 65. It is preferable to be provided at a predetermined position along at least two sides of the above. Furthermore, the protrusion (including the protrusion 65e and the protrusion 65f) is not limited to the shape shown in FIG. 50, and as shown in FIG.
For example, it is preferable that the shape is partially formed at intervals of 45 degrees around the axis L. In this case, it is preferable that the protrusion 65e and the protrusion 65f described above be formed apart from each other.

Further, the piezoelectric element 65 and the adhesive layer 67 shown in FIG. 50 are not limited to the square shape.
It may be rectangular as shown in FIG. In this case, in the rectangular piezoelectric element 65 and the adhesive layer 67, two of the four sides are longer than the two sides having the length W, and two sides of the four sides having the length W are in the X1 direction ( Alternatively, it is preferably provided parallel to the X2 direction). In addition, (the protrusion 65
The protrusions (including e and the protrusions 65f) are preferably provided along two longer sides than the two sides having the length W of the four sides of the rectangle of the piezoelectric element 65. Furthermore, it is preferable that the above-mentioned protrusions 65e and 65f be formed so as to extend in the vertical direction on the same plane in the X1 direction. In this case, it is preferable that the protrusion 65e and the protrusion 65f described above be formed apart from each other.

The shapes of the pressure chamber 2 and the ink pool 4 shown in FIG. 47 are not limited to the truncated pyramids as shown in FIG. 53, and may be truncated cones. In this case, the side surface portion 2c
And the side surface portion 2d are integrally formed, and the side surface portion 4c and the side surface portion 4 are formed.
It is preferable that d is integrally formed. Further, the piezoelectric element 65 and the adhesive layer 67 have a radius (W ×
A circle of (1/2)) is preferable. In addition, it is preferable that the protrusion (including the protrusion 65e and the protrusion 65f) is provided along the circumference of the circle of the piezoelectric element 65. Further, (including the protrusion 65e and the protrusion 65f)
It is preferable that the protrusion has a shape formed in a portion (area) excluding a circle having a radius (s1 + t1) centered on the axis L and having a radius s1 centered on the axis L. In addition, it is preferable that the above-mentioned protrusions 65e and 65f are integrally formed.

When the pressure chamber 2 and the ink pool 4 shown in FIG. 53 are frustoconical, the projection (including the projection 65e and the projection 65f) has the shape shown in FIG. However, as shown in FIG. 54, the piezoelectric element 6
It is preferably provided at a predetermined position along the circumference of the circle of 5. Further, the protrusion (including the protrusion 65e and the protrusion 65f) has a radius (s1 + t1 ×) centered on the axis L.
It is preferable that the shape is partially formed on the circumference of (1/2) at a predetermined distance, for example, at an interval of 45 degrees around the axis L. In this case, it is preferable that the protrusion 65e and the protrusion 65f described above be formed apart from each other.

The ink jet recording head 60 according to the sixth embodiment is not limited to the piezoelectric element 65 as long as it is an element that presses the pressure chamber 2 via the vibration plate 66. Examples of the element that presses the pressure chamber 2 via the diaphragm 66 include an electrostrictive element, a magnetostrictive element, and a shape memory alloy. In this case, when any of the electrostrictive element, the magnetostrictive element, and the shape memory alloy moves / drives in the a and b directions instead of the piezoelectric element 65, any of the electrostrictive element, the magnetostrictive element, and the shape memory alloy,
By pressing the pressure chamber 2 via the diaphragm 66,
It is preferable to change the pressure inside the pressure chamber 2 and eject the ink 11 from the nozzle 1 as an ink droplet.

In the ink jet recording heads 10, 20, 30, 40, 50 and 60 of the first to sixth embodiments, the nozzle 1 is formed in the nozzle plate 9 and directly communicates with the pressure chamber 2. However, the pressure chamber 2 may be communicated via a pipe (not shown).

Further, as the droplet discharge head according to the present invention, in the first to sixth embodiments, the ink jet recording heads 10 and 2 for discharging the ink droplets 12 onto the surface of the recording paper are used.
The case of 0, 30, 40, 50, 60 has been described, but the present invention is not limited to this. A high pressure is required to eject a highly viscous liquid, but in the case of the present invention, the volume displacement efficiency is high, so a high pressure can be easily obtained. For example, it is also suitably used for an organic EL display film forming apparatus in which a water-soluble organic material is adhered on a substrate according to a predetermined pattern. Further, it is also suitably used in a solder bump forming apparatus that forms a bump by discharging molten solder onto a substrate.

[0258]

The droplet discharge head of the present invention can discharge droplets at a low voltage.

[Brief description of drawings]

FIG. 1 is a sectional view showing a structure of an inkjet recording head according to a first embodiment.

FIG. 2A is a plan view showing the structure of the inkjet recording head according to the first embodiment, and FIG.
FIG. 3 is a diagram corresponding to FIG. 1 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 2 (a).

FIG. 3 is a cross-sectional view showing an ink droplet ejection operation of the inkjet recording head according to the first embodiment.

FIG. 4A is a plan view showing the structure of the inkjet recording head according to the first embodiment, and FIG.
FIG. 5 is a diagram corresponding to FIG. 1 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG.

5A is a plan view showing the structure of the ink jet recording head according to the first embodiment, and FIG.
FIG. 6 is a diagram corresponding to FIG. 1 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG.

FIG. 6A is a plan view showing the structure of the inkjet recording head according to the first embodiment, and FIG.
FIG. 7 is a diagram corresponding to FIG. 1 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG.

FIG. 7A is a plan view showing the structure of the inkjet recording head according to the first embodiment, and FIG.
FIG. 8 is a diagram corresponding to FIG. 1 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG.

FIG. 8A is a plan view showing the structure of the inkjet recording head according to the first embodiment, and FIG.
FIG. 9 is a diagram corresponding to FIG. 1 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG.

FIG. 9A is a plan view showing the structure of the inkjet recording head according to the first embodiment, and FIG.
9 is a diagram corresponding to FIG. 1 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 9 (a).

FIG. 10 is a sectional view showing an inkjet recording head according to the second embodiment.

11A is a plan view showing the structure of the inkjet recording head according to the second embodiment, FIG.
11B is a diagram corresponding to FIG. 10 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 11A.

FIG. 12 is a cross-sectional view showing an ink droplet ejection operation of the inkjet recording head according to the second embodiment.

13A is a plan view showing the structure of the inkjet recording head according to the second embodiment, FIG.
13B is a view corresponding to FIG. 10 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 13A.

14A is a plan view showing the structure of an inkjet recording head according to the second embodiment, FIG.
14B is a diagram corresponding to FIG. 10 and showing a cross section taken along the line XX ′ of the structure of the inkjet recording head of FIG. 14A.

15A is a plan view showing the structure of the inkjet recording head according to the second embodiment, FIG.
FIG. 15B is a view corresponding to FIG. 10 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 15A.

16A is a plan view showing the structure of the inkjet recording head according to the second embodiment, FIG.
16B is a diagram corresponding to FIG. 10 and showing a cross section XX ′ of the structure of the inkjet recording head of FIG. 16A.

17 (a) is a plan view showing the structure of the inkjet recording head according to the second embodiment, FIG.
17B is a diagram corresponding to FIG. 10 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 17A.

18A is a plan view showing the structure of the inkjet recording head according to the second embodiment, FIG.
FIG. 19B is a view corresponding to FIG. 10 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 18A.

FIG. 19 is a cross-sectional view showing an inkjet recording head according to the third embodiment.

20A is a plan view showing the structure of an inkjet recording head according to a third embodiment, FIG.
20B is a diagram corresponding to FIG. 19 and showing a cross section taken along the line XX ′ of the structure of the inkjet recording head of FIG. 20A.

FIG. 21 is a cross-sectional view showing an ink droplet ejection operation of the inkjet recording head according to the third embodiment.

22A is a plan view showing the structure of the inkjet recording head according to the third embodiment, FIG.
22B is a diagram corresponding to FIG. 19 and showing a cross section taken along the line XX ′ of the structure of the inkjet recording head of FIG. 22A.

23A is a plan view showing the structure of an inkjet recording head according to a third embodiment, FIG.
23B is a view corresponding to FIG. 19 and showing a cross section taken along the line XX ′ of the structure of the inkjet recording head of FIG. 23A.

24A is a plan view showing the structure of an inkjet recording head according to a third embodiment, FIG.
24B is a diagram corresponding to FIG. 19 and showing a cross section taken along the line XX ′ of the structure of the inkjet recording head of FIG. 24A.

25A is a plan view showing the structure of an inkjet recording head according to the third embodiment, FIG.
25B is a diagram corresponding to FIG. 19 and showing a cross section taken along the line XX ′ of the structure of the inkjet recording head of FIG. 25A.

FIG. 26 (a) is a plan view showing the structure of the inkjet recording head according to the third embodiment, FIG.
FIG. 26B corresponds to FIG. 19 and is a view showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 26A.

27A is a plan view showing the structure of an inkjet recording head according to the third embodiment, FIG.
27B is a diagram corresponding to FIG. 19 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 27A.

FIG. 28 is a cross-sectional view showing an inkjet recording head according to the fourth embodiment.

29A is a plan view showing the structure of an inkjet recording head according to a fourth embodiment, FIG.
FIG. 29B is a diagram corresponding to FIG. 28 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 29A.

FIG. 30 is a cross-sectional view showing the ink droplet ejection operation of the inkjet recording head according to the fourth embodiment.

31A is a plan view showing the structure of an inkjet recording head according to a fourth embodiment, FIG.
28B is a diagram corresponding to FIG. 28 and showing a cross section taken along the line XX ′ of the structure of the inkjet recording head of FIG. 31A.

32 (a) is a plan view showing the structure of the inkjet recording head according to the fourth embodiment, FIG.
32B is a diagram corresponding to FIG. 28 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 32A.

FIG. 33A is a plan view showing the structure of the inkjet recording head according to the fourth embodiment, and FIG.
28B is a diagram corresponding to FIG. 28 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG.

34A is a plan view showing the structure of an inkjet recording head according to a fourth embodiment, FIG.
28B is a diagram corresponding to FIG. 28 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 34A.

FIG. 35 (a) is a plan view showing the structure of the inkjet recording head according to the fourth embodiment, and FIG.
35B is a diagram corresponding to FIG. 28 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 35A.

36 (a) is a plan view showing the structure of the inkjet recording head according to the fourth embodiment, FIG.
28B is a diagram corresponding to FIG. 28 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG.

FIG. 37 is a cross-sectional view showing an inkjet recording head according to the fifth embodiment.

38A is a plan view showing the structure of an inkjet recording head according to the fifth embodiment, FIG.
38B is a diagram corresponding to FIG. 37 and showing a cross section taken along the line XX ′ of the structure of the inkjet recording head of FIG. 38A.

FIG. 39 is a cross-sectional view showing an ink droplet ejection operation of the inkjet recording head according to the fifth embodiment.

40 (a) is a plan view showing the structure of an inkjet recording head according to the fifth embodiment, FIG.
40B is a diagram corresponding to FIG. 37 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 40A.

41 (a) is a plan view showing the structure of an inkjet recording head according to the fifth embodiment, FIG.
41B is a diagram corresponding to FIG. 37 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 41A.

42 (a) is a plan view showing the structure of an inkjet recording head according to the fifth embodiment, FIG.
42B is a diagram corresponding to FIG. 37 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 42A.

43 (a) is a plan view showing the structure of an inkjet recording head according to the fifth embodiment, FIG.
FIG. 43B is a view corresponding to FIG. 37 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 43A.

44 (a) is a plan view showing the structure of the inkjet recording head according to the fifth embodiment, and FIG.
FIG. 43B is a view corresponding to FIG. 37 and showing a cross section taken along the line XX ′ of the structure of the inkjet recording head of FIG. 44A.

45A is a plan view showing the structure of an inkjet recording head according to a fifth embodiment, FIG.
FIG. 38B is a diagram corresponding to FIG. 37 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 45A.

FIG. 46 is a sectional view showing an ink jet recording head according to the sixth embodiment.

47 (a) is a plan view showing the structure of an inkjet recording head according to the sixth embodiment, and FIG.
47B is a diagram corresponding to FIG. 46 and showing a cross section taken along the line XX ′ of the structure of the inkjet recording head of FIG. 47A.

FIG. 48 is a cross-sectional view showing the ink droplet ejection operation of the inkjet recording head according to the sixth embodiment.

49 (a) is a plan view showing the structure of an inkjet recording head according to the sixth embodiment, and FIG.
49B is a diagram corresponding to FIG. 46 and showing a cross section taken along the line XX ′ of the structure of the inkjet recording head of FIG. 49A.

50 (a) is a plan view showing the structure of an inkjet recording head according to the sixth embodiment, FIG.
50B is a diagram corresponding to FIG. 46 and showing a cross section taken along the line XX ′ of the structure of the inkjet recording head of FIG.

51 (a) is a plan view showing the structure of an ink jet recording head according to a sixth embodiment, FIG.
FIG. 51B is a diagram corresponding to FIG. 46 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 51A.

52 (a) is a plan view showing the structure of an inkjet recording head according to the sixth embodiment, FIG.
FIG. 52B is a diagram corresponding to FIG. 46 and showing a cross section taken along the line XX ′ of the structure of the inkjet recording head of FIG. 52A.

53 (a) is a plan view showing the structure of an inkjet recording head according to the sixth embodiment, FIG.
FIG. 54B is a diagram corresponding to FIG. 46 and showing an XX ′ cross section of the structure of the inkjet recording head of FIG. 53A.

54 (a) is a plan view showing the structure of an inkjet recording head according to the sixth embodiment, FIG.
FIG. 54B corresponds to FIG. 46 and is a view showing a cross section taken along the line XX ′ of the structure of the inkjet recording head of FIG. 54A.

FIG. 55 is a cross-sectional view showing a conventional inkjet recording head.

FIG. 56 is a cross-sectional view showing an ink droplet ejection operation of a conventional inkjet recording head.

[Explanation of symbols]

1 nozzle 1a entrance 1b exit 1c, 1d Side part 2 Pressure chamber 2a Bottom part 2b Upper surface 2c, 2d Side part 3 supply ports 3a entrance 3b exit 3c Top part 3d bottom part 4 ink pool 4a Bottom part 4b upper surface 4c, 4d Side part 5 Piezoelectric element 5a upper surface 5b Bottom part 5c, 5d Side part 6 diaphragm 7,7 'adhesive layer 8a 1st plate 8b Second plate 8c Third plate 9 nozzle plate 9a side 10 Inkjet recording head 11 ink 12 ink drops 13 ink 20 inkjet recording head 25 Piezoelectric element 25a upper surface 25b bottom part 25c, 25d side part 26 diaphragm 26a, 26b groove 27, 27 'adhesive layer 30 inkjet recording head 35 Piezoelectric element 35a Upper surface part 35b bottom part 35c, 35d Side part 36 diaphragm 36a, 36b Projection 37, 37 'adhesive layer 40 inkjet recording head 45 Piezoelectric element 45a upper surface 45b Bottom part 45c, 45d Side part 46 diaphragm 46a, 46b Projection 47 Adhesive layer 50 inkjet recording head 55 Piezoelectric element 55a Upper surface part 55b Bottom part 55c, 55d Side part 55e, 55f Projection 56 diaphragm 57, 57 'adhesive layer 60 inkjet recording head 65 Piezoelectric element 65a upper surface 65b Bottom part 65c, 65d Side part 65e, 65f Projection 66 diaphragm 67 Adhesive layer 80 External power supply 100 inkjet recording head 101 nozzles 102 pressure chamber 103 supply port 104 ink pool 105 Piezoelectric element 106 diaphragm 107 adhesive layer 108a First plate 108b Second plate 108c Third plate 109 nozzle plate 111 ink 112 ink drops 113 ink

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B41J 2/055 H05B 33/14 A H05B 33/10 B41J 3/04 103A 33/14 F term (reference) 2C057 AF03 AF52 AG38 AG44 AG59 AG68 AP25 BA04 BA09 BA14 3K007 AB18 EB00 FA01 4F033 AA01 BA01 CA07 DA05 EA06 NA01 4F041 AA02 AB01 BA10 4F042 AA02 AB00 BA07 CB03 CB24

Claims (21)

[Claims] 1. A pressure chamber for pressurizing a liquid, an opening for ejecting the liquid as a droplet is provided in the pressure chamber, a vibrating plate provided on the pressure chamber, and a vibrating plate on the vibrating plate. A displacement generating element provided, wherein the displacement generating element and the diaphragm are partially joined, and the pressure chamber is a flexural deformation of the diaphragm that occurs based on the displacement generated by the displacement generating element. As a result, the internal pressure is changed, and the droplet is ejected from the opening based on the change in the pressure of the pressure chamber. 2. The droplet discharge head according to claim 1, further comprising an adhesive portion that partially joins the displacement generating element and the vibration plate. 3. The droplet discharge head according to claim 2, wherein the displacement generating element has a circular shape, and the bonding portion is provided along the circumference of the circle. 4. The droplet discharge head according to claim 2, wherein the displacement generating element has a square shape, and the bonding portion is provided along at least two sides of the four sides of the square. Droplet ejection head. 5. The droplet discharge head according to claim 2, wherein a groove is formed on a surface of the vibration plate, the adhesive section is provided in the groove, and the adhesive section and the diaphragm are provided. A droplet discharge head on which the displacement generating element is provided. 6. The droplet discharge head according to claim 5, wherein the displacement generating element has a circular shape, and the bonding portion and the groove are provided along a circumference of the circle. head. 7. The droplet discharge head according to claim 5, wherein the displacement generating element has a rectangular shape, and the bonding portion and the groove are along at least two sides of the four sides of the square. A droplet discharge head provided in. 8. The droplet discharge head according to claim 2, wherein a protrusion is formed on a surface of the vibration plate, the adhesive is provided on the protrusion, and the adhesive is provided on the adhesive. A droplet discharge head provided with the displacement generating element. 9. The droplet discharge head according to claim 2, wherein a protrusion is formed on the displacement generating element, and the protrusion is provided on the adhesive portion. 10. The droplet discharge head according to claim 8, wherein the displacement generating element has a circular shape, and the bonding portion and the protrusion are provided along the circumference of the circle. Droplet ejection head. 11. The droplet discharge head according to claim 8, wherein the displacement generating element has a square shape, and the adhesive portion and the protrusion are at least two sides of the four sides of the square. A droplet discharge head provided along the line. 12. The droplet discharge head according to claim 1, wherein a protrusion is formed on a surface of the vibration plate, and further, an adhesive portion that joins the displacement generating element and the protrusion is provided. Droplet ejection head. 13. The droplet discharge head according to claim 1, wherein the displacement generating element is formed with a protrusion, and further includes an adhesive portion that joins the protrusion and the vibration plate. Discharge head. 14. The droplet discharge head according to claim 12, wherein the displacement generating element has a circular shape, and the protrusion is provided along a circumference of the circle. . 15. The droplet discharge head according to claim 12 or 13, wherein the displacement generating element has a square shape, and the protrusion extends along at least two sides of the four sides of the square. A droplet discharge head provided. 16. The method according to claim 3, 4, 6, 7, 10, 11,
In the droplet discharge head according to any one of 14 and 15, the shape of the pressure chamber is a truncated pyramid, and the opening is provided on the first surface of the truncated pyramid. A second surface larger than the first surface of the table is formed by the vibrating plate, and the displacement generating element is provided above the pressure chamber so that the displacement generated by the displacement generating element is transmitted to the second surface. Droplet discharge head. 17. The droplet discharge head according to claim 3, wherein the shape of the pressure chamber is a truncated cone, and the first surface of the truncated cone has the above-mentioned shape. An opening is provided, a second surface of the truncated cone that is larger than the first surface is formed by the vibrating plate, and the displacement generating element transmits the displacement generated by the displacement generating element to the second surface. A droplet discharge head provided above the pressure chamber. 18. The droplet discharge head according to claim 1, further comprising: a pool containing the liquid, a pool communicating with the pool and the pressure chamber, and being stored in the pool. And a supply port for supplying the liquid to the pressure chamber. 19. The droplet discharge head according to claim 1, wherein the droplet discharge head is used in an inkjet recording device. 20. The droplet discharge head according to claim 1, wherein the droplet discharge head is used in an organic EL display film forming apparatus. 21. The droplet discharge head according to claim 1, wherein the droplet discharge head is used in a solder bump forming apparatus.