JP3160997B2 - Ink jet print head and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention performs printing by causing ink in a pressure chamber to fly from a nozzle opening toward a recording medium when a printing signal is input, and forming dots on the recording medium with the ink droplets. The present invention relates to an on-demand type ink jet print head.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 6, an ink jet print head of this type has a vibration surface 101 of a laminated vibrator 100 opposed to a nozzle inlet opening 102 and a vibrator. The vicinity of the vibrating surface was filled with the RTV rubber 103. (Japanese Unexamined Patent Publication No. 1-115638
Alternatively, as shown in FIGS. 7A and 7B, the piezoelectric element 110 was supported by a hard member 112 via a flexible material 111. (Japanese Patent Application Laid-Open No. 58-1119871)
These print heads apply a print signal to the piezoelectric element to expand and contract the piezoelectric element, and the ink pressure generated at this time causes ink droplets to fly from the nozzle openings to form dots on printing paper. It is to let.

[0003]

However, in the prior art shown in FIG. 6, since the fixing portion of the piezoelectric element 100 is fixed to the supporting substrate 105 by the bottom surface 104, it is necessary to arrange the nozzle openings at a high density. However, there was a problem that it was extremely difficult. That is, in order to arrange the nozzle openings at high density, it is necessary to narrow the width of the piezoelectric element 100. However, the fixing strength only by the bottom surface 104 of the piezoelectric element alone is not sufficient, and the fixing portion is not formed due to the vibration of the piezoelectric element. Is likely to be peeled off. In addition, there is a problem in that, by fixing a plurality of piezoelectric elements to the integral support substrate 105, there is a high possibility of mechanical crosstalk through the support substrate 105 and the piezoelectric element 100.

In order to solve these problems, in the prior art shown in FIG. 7, the periphery of the piezoelectric element 110 is supported by a flexible material 111 made of silicon rubber.
However, in such a configuration, the piezoelectric element 11
There is a problem that the rate of absorption of vibration of 0 by the flexible material 111 is high, and the efficiency of energy transmitted to the ink is low. Therefore, it is necessary to input a larger amount of energy to drive the piezoelectric element 110, and the driving circuit and the power supply are complicated.

In addition, since the piezoelectric element 110 is often exposed during the process of assembling the print head, there is also a problem that the possibility of breakage during assembly is extremely high.

[0006]

According to the present invention, there is provided an ink jet print head comprising a plurality of nozzle openings, a plurality of pressure chambers communicating with the nozzle openings, and a piezoelectric element arranged corresponding to each pressure chamber. An ink jet print head comprising: a support substrate for fixing the piezoelectric element; and a holding member for fixing the support substrate, wherein the piezoelectric element is operated to discharge ink in the pressure chamber as ink droplets from nozzle openings. Is a free part whose one end can freely vibrate,
The other end includes a fixed portion fixed to the support substrate, and the fixed portion is sandwiched between the first support substrate and the second support substrate on two longitudinal surfaces of the piezoelectric elements corresponding to the plurality of pressure chambers. And the first support substrate and the second support substrate are fixed to a holding member. In the ink jet print head, the gap between the step portion of the first support substrate and the second support substrate and the free portion of the piezoelectric element is entirely or partially filled with a flexible material made of silicon rubber. It is characterized by being. Further, in such an ink jet print head,
The step portion of the first support substrate and the second support substrate is formed so as to cover the free portion end of the piezoelectric element. Further, in such an ink jet print head, the piezoelectric element is a laminated piezoelectric element, and one or both of the first support substrate and the second support substrate is spaced from the vicinity of the rear end of the fixed side of the piezoelectric element. A second step portion having the second step portion. Further, in the method of manufacturing an ink jet print head, one surface of a piezoelectric plate serving as a piezoelectric element is fixed to a first substrate serving as a first support substrate, and the other surface of the piezoelectric plate is connected to a second support substrate. Fixing to the second substrate to be formed, then cutting to a desired width to form a beam-shaped vibration unit including the piezoelectric element, the first support substrate, and the second support substrate, and holding the beam-shaped vibration unit Fixing the beam-shaped vibration unit to the holding member.

Further, according to the method of manufacturing an ink jet print head of the present invention, one surface of a piezoelectric plate serving as a piezoelectric element is fixed to a first substrate serving as a first support substrate, and the other surface of the piezoelectric plate is attached to the first substrate. Fixing to a second substrate serving as a second support substrate, then cutting to a desired width to form a beam-shaped vibration unit including a piezoelectric element, a first support substrate, and a second support substrate; Fixing the beam-shaped vibration unit to the holding member that holds the vibration unit.

[0008]

1 (a) and 1 (b) are a partial plan view and a sectional view showing an embodiment of a drive unit of an on-demand type ink jet print head according to the present invention. In the drawings, reference numeral 1 denotes a nozzle plate having a nozzle opening 2. Reference numeral 3 denotes a diaphragm, and a pressure chamber 4 is formed between the diaphragm 3 and the nozzle plate 1. The diaphragm 3 has the same number of vibrating parts 5 as the nozzle openings 2.
And a pressure chamber forming plate 6 and a wall 7 for managing a gap between the nozzle plate 1 and the pressure chamber forming plate 6. The pressure chamber forming plate 6 is formed by molding a polymer material having heat resistance and elasticity, such as polyimide, into a film shape. The pressure chamber 4 is isolated only in the vertical direction by walls 7, 7, 7,.
Both sides are open so that ink is supplied from ink channels 9, 9, 9,... Provided in the holding member 8. Reference numeral 10 denotes a piezoelectric element that applies pressure to the pressure chamber 4. In this embodiment, the piezoelectric element 10 is a piezoelectric element in which a piezoelectric material and a conductive material are alternately laminated in layers. This means that by reducing the thickness of each piezoelectric layer that forms the piezoelectric element, the voltage for simultaneously applying a signal to each piezoelectric layer is reduced, and the drive voltage required to form ink droplets is reduced as much as possible. This is for simplifying the drive circuit by reducing the size. As shown in FIG. 2, the piezoelectric element 10 is divided into two upper and lower regions in the axial direction, and has an active region that expands and contracts when an electric field is applied, and an inactive region that is not exposed to the electric field. The active region has its tip fixed to a vibrating section 5 formed on the diaphragm 3. An inactive region of the piezoelectric element 10 is sandwiched and fixed between the first support substrate 11 and the second support substrate 12 to form a beam vibration unit 28. As the first support substrate 11 and the second support substrate 12, those having a large acoustic impedance are used to reduce the escape of the vibration of the piezoelectric element 10. Further, as described later, a material having a free-cutting property is used in production. The supporting substrates 11 and 12 holding the piezoelectric element 10 are
Are supported on both sides so as to sandwich the piezoelectric element 10, so that the fixing area between the piezoelectric element 10 and the supporting substrates 11, 12 can be increased, and sufficient fixing strength can be obtained. Further, it is effective for efficiently transmitting the vibration to the ink. As an example of evaluating the transmission efficiency of vibration by an experiment, the result of evaluating the natural frequency of the piezoelectric element 10 for the supporting method is shown below.

Supporting method Natural frequency One side: about 160 kHz Both sides: about 180 kHz The free length of the piezoelectric element is unified to 4 mm.
By sandwiching from both sides by 1, 12,
The natural frequency of the piezoelectric element increases, that is, the escape of the vibration of the piezoelectric element to the support substrate decreases, and the vibration is efficiently transmitted to the ink. A large natural frequency of the piezoelectric element is equivalent to a high displacement speed of the vibrator if the displacement amount of the vibrator is the same, and it is possible to give the ink the energy for the ink droplet to fly at a sufficient speed. it can.

In this embodiment, the supporting substrates 11 and 12
As shown in FIGS. 2B and 2C, a conductive thin film layer 11a, 12a is formed on a surface of an electrically insulating material made of glass ceramic. Also,
An active region of the piezoelectric element 10, that is, a free portion, is in contact with the first support substrate 11 and the second support substrate 12, and a step portion 21 maintaining a certain distance from the piezoelectric element 10 so that vibration of the piezoelectric element 10 is not hindered. 22 are provided. The steps 21 and 22 extend almost to the free ends of the piezoelectric element 10. The material of the piezoelectric element 10 used in the present embodiment is a ceramic having a perovskite structure of a titanate / lead zirconate composite, but this kind of material is generally very brittle because of a large displacement due to the piezoelectric effect. It is easy to do. Therefore, in the manufacturing process, if it comes into contact with other parts, it will be damaged. The main cause of the breakage of the piezoelectric element is that when the free portion comes into contact with another component or the like, the fixed end of the piezoelectric element, that is, the end 23 of the step portion of the support substrates 11 and 12,
24 is excessively stressed. by this,
A minute crack is formed in the piezoelectric material, or the electrode is disconnected. Therefore, the supporting substrates 11 and 12 and the stepped portions 2 are provided so that an external force is not directly applied to the free portion of the piezoelectric element.
It is effective to protect by 1, 22. According to further experiments, the distance between the piezoelectric element 10 and the step portions 21 and 22 of the support substrates 11 and 12 is not more than twice the thickness T of the piezoelectric element,
In addition, it has been confirmed that it is extremely effective that the length is at least １ ／ of the length L of the piezoelectric element. With such a configuration, even if a force is applied to the beam-shaped vibration unit 28 from the lateral direction, the support substrates 11 and 12 are provided, so that breakage of the piezoelectric element 10 can be largely prevented. Steps 21 and 2 of support substrate
The longer the length of the front end side of 2 is, the more effective it is. Desirably, the entire free length of the piezoelectric element is protected by the step portions 21 and 22 of the support substrates 11 and 12, thereby producing a print head. , The destruction of the piezoelectric element 10 can be minimized. In the present embodiment, the piezoelectric element 10 is sandwiched between the first support substrate 11 and the second support substrate 12 and has a structure in which the piezoelectric element 10 is protected to almost the distal end. Can be. Moreover,
Step portions 21 and 22 between piezoelectric element 10 and support substrates 11 and 12
By filling rubber-like silicon with high flexibility in the gap between the piezoelectric element 10 and the piezoelectric element 10, it is possible to more reliably prevent the piezoelectric element 10 from being broken without hindering the vibration in the longitudinal direction of the piezoelectric element 10. Silicon has step portions 21 and 22 and piezoelectric element 1
It may be filled over the entire gap with zero or only near the fixed end of the piezoelectric element 10. Since silicon is filled in the gap between the step portions 21 and 22 and the piezoelectric element 10, it is easy to fill a certain amount only in this gap.
Even if an external force due to contact with other parts or the like is applied to the beam-shaped vibration unit 28, the silicon filled in the narrow gap between the piezoelectric element 10 and the step portions 21 and 22 causes the external force in the bending direction to the piezoelectric element to be piezoelectrically deformed. The element can be sufficiently released so as not to be destroyed. Filling the space between the piezoelectric element 10 and the step portions 21 and 22 of the support substrates 11 and 12 with silicon also has the effect of reducing the lateral vibration of the piezoelectric element 10. Further, since a part of the energy input to the piezoelectric element becomes heat energy, the vibrating piezoelectric element generates heat, and has an effect of radiating the heat to the outside.

The piezoelectric element 10 is constituted by alternately laminating a plurality of piezoelectric layers 15 made of a composite material of perovskite ceramics of a titanate / lead zirconate type and a second electrode 14. One electrode, electrode 14 in this embodiment, is interrupted at approximately the center 16 and is distributed at two locations. The first electrode 13 is exposed on one end face, and the second electrode 14 is exposed on the other end face, and conductive layers 17 and 18 are formed on each end face. Are connected in parallel by the conductive layer 17, and the electrodes 14, 14, 14... Are connected in parallel by the conductive layer 18. In addition, the external electrodes 19 and 20 are
18 are formed so as to be electrically connected to each other. The electrode 20 is formed so as to cover the active region of the piezoelectric element 10, that is, the entire free length. This is because, when the number of the piezoelectric material layers is even, an electric field is also applied to the outermost piezoelectric material layer of the piezoelectric element (hereinafter, referred to as an outermost piezoelectric layer) to cause distortion. If no distortion occurs in the outermost piezoelectric layer, the outermost piezoelectric layer acts to inhibit vibration of the piezoelectric element. Therefore, unless the electric power applied to the piezoelectric element is increased, a predetermined amount of displacement cannot be obtained, and the energy efficiency deteriorates. Further, there is a problem that stress is applied to the interface between the outermost piezoelectric layer and the inside thereof, and there is a high possibility that interfacial separation will occur. FIG. 3 shows the electrode configuration of the piezoelectric element and the configuration of the support substrate when the number of piezoelectric material layers is odd.

The surface of the piezoelectric element 10 on the side of the external electrode 20 is the first
The external electrode 1 is fixed to the support substrate 11 with an adhesive.
The beam-side vibration unit 28 is formed by fixing the surface on the 9th side to the second support substrate 12 with an adhesive in the same manner. The surface of the piezoelectric element 10 and the surfaces of the first and second support substrates 11 and 12 have moderate irregularities. Even if an electrically insulating adhesive such as a thermosetting polyimide-based adhesive is used, the surface of the piezoelectric element 10 External electrodes 19, 20 and the first and second support substrates 1
The conductive thin layers on 1 and 12 are in point contact with each other, and good conductivity can be obtained. The end face electrode 18 of the piezoelectric element 10 is formed so as to cover the entire end face in order to conduct with all the electrodes 14, 14, 14,. The second support substrate 12 has an end face electrode 18 near the end face on the fixed end side of the piezoelectric element 10.
The second step portion 26 is provided so as not to contact with the second step portion. This can prevent an electrical short circuit between the end face electrode 18 and the conductive thin layer on the second support substrate 12. The second step 26 may be provided only on the first support substrate 11 or may be provided on the second support substrate 11.
The support substrate 12 may be provided. A conductive thin layer is also formed on the upper surface of the second step portion 26, and conduction with the external electrode 19 is obtained. Further, it is desired that the thickness of the piezoelectric element is the minimum necessary for causing the ink to fly at a predetermined speed and ink amount. However, when the thickness of the piezoelectric element is small, it is difficult to connect the piezoelectric element to a printed wiring board. for that reason,
By providing the second step 26, the first support substrate 11
The distance between the conductive thin film and the second support substrate 12 can be increased, and the occurrence of an electrical short circuit between the conductive thin layers can be reduced. Making the step end portion 27 of the second step 26 a smooth radius or a tapered shape is effective in preventing the conductive thin layer from breaking at the step end portion 27. In the embodiment shown in FIG. 2, no conductive thin layer is arranged near the end of the step portion 24 of the second support substrate 12. Second
Since the support substrate 12 is made of an electrically insulating material, it does not electrically short-circuit with the external electrode 17 of the piezoelectric element 10, but can define a fixed end of the piezoelectric element 10.

The beam-shaped vibration unit 28 is fixed to a holding member 8 for holding the vibration unit. As shown in FIG. 4, the holding member 8 has a hole 30 for positioning the beam-shaped vibration unit 28, and the beam-shaped vibration unit 28 is inserted into the hole 30. A groove 31 is formed in the hole 30 of the holding member 8 so as not to contact the side surface of the piezoelectric element 10. As a result, the free portion of the piezoelectric element 10 is
To prevent the vibration of the beam-shaped vibration unit 28 from being disturbed, and at the same time, prevent the beam-shaped vibration unit 28 from being broken due to the free portion of the piezoelectric element 10 contacting the holding member 8 during insertion. be able to. Further, by adopting such a configuration, since the beam-shaped vibration units 28 are arranged via the holding member 8 having extremely high rigidity as compared with the beam-shaped vibration unit 28, the mechanical vibration between the beam-shaped vibration units 28 is reduced. Crosstalk can be significantly reduced. The stronger the fixing between the holding member 8 and the beam-shaped vibration unit 28, the more effective it is against mechanical crosstalk. Further, before inserting the beam-shaped vibration units 28 into the holding member 8, it is possible to inspect one by one and to judge the quality, or it is also possible to replace the beam-shaped vibration units 28 which have malfunctioned one by one. Therefore, maintenance and manufacturing costs can be reduced.

The free end of the piezoelectric element 10 of the beam-shaped vibration unit 28 held by the holding member 8 is fixed to the vibration part 5 formed on the vibration plate 3. The support substrates 11 and 12 may be fixed to the portion of the vibration plate 3 having a certain distance from the vibration unit 5 or may not be fixed to the vibration plate 3.

The conductive thin layers on the first support substrate 11 and the second support substrate 12 are electrically connected to a printed circuit board 29.

Next, an embodiment of a method for manufacturing the above-described ink jet print head will be described.

First, a piezoelectric plate is made. As shown in FIG. 5A, a layer 13 to be the first electrode 13 is formed of a silver-palladium (Ag-Pd) -based or platinum (Pt) -based conductive paint prepared in a paste form on the surface plate 120. And a second layer 15 'that becomes a piezoelectric layer 15 by a composite material of a perovskite-based titanate / lead zirconate ceramic, which is a piezoelectric element material adjusted to a paste state, and a silver-palladium (Ag-Pd) -based or A third layer 14 ′ serving as the second electrode 14 is alternately thinly applied with a platinum (Pt) -based conductive paint. At this time, when one of the electrode layers 14 ′ is formed, the electrode layer 14 ′ is interrupted at the center 16 and dispersed at two locations. An electrode constituent material is applied so that the first electrode layer 13 'is exposed from one end face 10'a and the second electrode layer 14' is exposed from the other end face 10'b. After drying in a plate shape with a predetermined number of layers in this way, the pressure is increased to a temperature of 1000 to 1200 ° C. for 1 hour.
After firing for about an hour, a piezoelectric plate 10 'as shown in FIG.
To form

The piezoelectric plate 10 'thus formed
Are the first electrode layers 13 ′, 13 ′,
13 'are exposed at one end face 10'a, the other end is covered with a piezoelectric material layer 15', and the second electrode layer 1 '
One end of each of 4 ', 14', 14 '... is exposed to the other end face 10'b, and the other end is covered with a piezoelectric material layer 15'.

Next, as shown in FIG.
By forming the conductive layers 17 ', 18' on the respective end faces of 0 ', the electrode layers 13', 13 ', 13',... Of the same polarity are formed by the conductive layer 17 'and the electrode layers 14', 14 ', 14'. '…
Are connected in parallel by the conductive layer 18. At the same time, the piezoelectric plate 1
The external electrode layers 19 ′ and 20 ′ are formed on the conductive layer 1
It is formed so as to be electrically connected to each of 7 ′ and 18 ′. At this time,
Preliminarily chamfering the end face 15a 'of the outermost piezoelectric material layer is effective in increasing the reliability of conduction of each of the electrode layers 17' and 19 'and 18' and 20 '.

As shown in FIG. 1D, the surface of the piezoelectric plate 10 ′ on the side of the external electrode layer 20 ′ is the first support substrate 11.
The external electrode layer 1 is fixed to the substrate 11 'by an adhesive.
The surface on the 9 ′ side is similarly fixed to the second substrate 12 ′ serving as the second support substrate 12 with an adhesive to form the vibration unit 28 ′.

As shown in FIG. 3E, the vibrating unit 28 'is cut by a so-called wire saw which cuts a metal wire by applying a grinding liquid in which particles are dispersed, so that the vibration unit 28' has a predetermined width at the same time as a virtual line. Then, a beam-shaped vibration unit 28 is formed. In this embodiment, the piezoelectric element 1
The titanate / lead zirconate composite perovskite ceramics used in Example No. 0 has excellent grinding properties. When cutting a laminate of different materials by grinding, if there is an extreme difference in grindability, the grinding speed will be different, and the material with good grindability will be cut in the direction perpendicular to the grinding direction at the lamination interface. , It is not possible to obtain the required dimensions. Therefore, the first,
It is desired that the second support substrates 11 and 12 have a free-cutting property equal to or higher than that of the piezoelectric element 10. The support substrate 11 of the present embodiment,
Since the glass ceramic used in No. 12 has very high grindability, a predetermined size can be easily obtained. Further, the same effect can be obtained by using the same material as the piezoelectric material used for the piezoelectric element 10 as the support substrate material.

The beam-shaped vibration unit 28 is attached to the holding member 8 (FIG. 4).
(See FIG. 3). Since the first and second support substrates 11 and 12 are strong and do not break even when they come into contact with the holding member 8, there is no need for precise positioning, and the manufacturing can be simplified.

Thereafter, the nozzle plate 1 is fixed, and the first
The conductive thin layers on the support substrate 11 and the second support substrate 12 are electrically connected to the printed circuit board 29, and the driving unit of the ink jet print head is completed.

[0024]

According to the ink jet print head of the present invention, there are provided a plurality of nozzle openings, a plurality of pressure chambers communicating with the nozzle openings, a piezoelectric element arranged corresponding to each pressure chamber, and the piezoelectric element. An ink jet print head comprising: a support substrate for fixing the support substrate; and a holding member for fixing the support substrate, and operating the piezoelectric element to discharge ink in the pressure chamber as ink droplets from a nozzle opening. It comprises a free part that can freely vibrate and a fixed part whose other end is fixed to the support substrate, and the fixed part is a first part on two longitudinal surfaces of each of the piezoelectric elements corresponding to the plurality of pressure chambers. The first support substrate and the second support substrate are fixed to the holding member so as to be fixed between the support substrate and the second support substrate, so that a fixed portion is provided for each piezoelectric element corresponding to each pressure chamber. When the two surfaces are fixed to the supporting member, sufficient fixing strength can be obtained, and at the same time, the two supporting members fixed to each of the two surfaces are fixed by the holding member. Escape to the support substrate side can be prevented, and the natural frequency of the piezoelectric element can be increased. Therefore, even if the ink jet print head is highly integrated, vibration can be efficiently transmitted to the ink and an ink jet print head with high reliability can be provided.

[Brief description of the drawings]

FIG. 1 is a view showing a main part of an ink jet print head of the present invention, wherein (a) is a plan view and (b) is a sectional view.

2A is a cross-sectional view showing a connection structure between a piezoelectric element of the present invention and a supporting substrate, FIG. 2B is a view from FIG. 2A, and FIG. 2C is a view from FIG. .

FIG. 3 is a cross-sectional view showing another connection structure between the piezoelectric element of the present invention and a support substrate.

FIG. 4A is a perspective view showing a holding substrate of the present invention,
(B) is a partially enlarged view.

FIGS. 5A to 5E are explanatory views of the manufacturing method of the present invention, wherein FIGS.

FIG. 6 is a sectional view of a conventional head.

7A is a partial plan view of a conventional head, and FIG. 7B is a cross-sectional view taken along line bb of FIG. 7A.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nozzle plate 2 Nozzle opening 3 Vibrating plate 4 Pressure chamber 5 Vibrating part 6 Pressure chamber forming plate 7 Wall 8 Holding member 9 Ink channel 10 Piezoelectric element 11 First support substrate 12 Second support substrate 13 First electrode of piezoelectric element Reference Signs List 14 Second electrode of piezoelectric element 15 Piezoelectric material layer 17, 18 End face electrode of piezoelectric element 19, 20 External electrode of piezoelectric element 21 Step of first support substrate 22 Step of second support substrate 23, 24 Support substrate step End of part 26 Second step part of support substrate 27 End part of second step part 28 Beam vibration unit 29 Printed circuit board 30 Hole of holding member

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41J 2/045 B41J 2/055 B41J 2/16

Claims (6)

(57) [Claims] A plurality of nozzle openings, a plurality of pressure chambers communicating with the nozzle openings, a piezoelectric element arranged corresponding to each of the pressure chambers, a support substrate for fixing the piezoelectric element, A holding member for fixing the support substrate, wherein the piezoelectric element is operated to discharge ink in the pressure chamber as ink droplets from the nozzle openings, wherein one end of the piezoelectric element can freely vibrate Free parts,
The other end includes a fixed portion fixed to the support substrate, and the fixed portion is provided on the first support substrate and the second support substrate on two longitudinal surfaces of the piezoelectric elements corresponding to the plurality of pressure chambers. An ink jet print head, being sandwiched and fixed, wherein the first support substrate and the second support substrate are fixed to a holding member. 2. A step portion having an interval from a free portion of a piezoelectric element is provided on the first support substrate and the second support substrate, and the step portion covers at least a vicinity of a fixed end of the piezoelectric element. The ink jet print head according to claim 1, wherein: 3. A space between a step portion of the first support substrate and the second support substrate and a free portion of the piezoelectric element is filled with a flexible material made of silicon rubber in whole or in part. The ink jet print head according to claim 2, wherein 4. The ink jet print head according to claim 2, wherein a step portion of the first support substrate and the second support substrate is formed so as to cover an end of a free portion of the piezoelectric element. 5. The piezoelectric element is a laminated piezoelectric element,
One of the first support substrate and the second support substrate,
4. The ink jet print head according to claim 2, wherein a second step portion having an interval from a vicinity of a rear end of the piezoelectric element on the fixed portion side is provided on both sides. 5. 6. The method for manufacturing an ink jet print head according to claim 1, wherein one surface of a piezoelectric plate serving as a piezoelectric element is fixed to a first substrate serving as a first support substrate. Fixing the other surface of the piezoelectric plate to a second substrate serving as a second support substrate, and then cutting the piezoelectric plate to a desired width to form a beam-shaped vibration unit including a piezoelectric element, a first support substrate, and a second support substrate And a step of fixing the beam-shaped vibration unit to a holding member that holds the beam-shaped vibration unit.