JPH0445945A - On-demand type ink jet print head - Google Patents

Abstract

PURPOSE:To eliminate deviations of the center of the dynamic pressure at a nozzle area and the center of a nozzle opening occurred due to a stretch of a piezoelectric device and eliminate separations of a nozzle opening member particularly at the periphery of the nozzle by forming a nozzle member integrally with a facing partition member and string partitioning member. CONSTITUTION:Clearances in a string of piezoelectric device 4 are filled with a material of resin group such as adhesive or filler whose Young's modulus is 20% or less than that of the piezoelectric device 4 and cured so as to form a partition b5 as a string partitioning member. A side face of a cavity 11 facing the piezoelectric device 4 forms a partition member a3 as a facing partition member made of the same material as the partition b5, and sticks fast to a substrate 1. A nozzle formation section 7 forming a nozzle 8 facing the cavity 11 is formed with a predetermined thickness and magnitude by a material equivalent to the partition b5 on end faces of the cavity 11, partition b5, piezoelectric device 4, and housing 2 opposite to the substrate 1 respectively.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention allows ink to fly as droplets or mist when printed data is received manually, and dots on recording paper due to these ink droplets or mistakes. The present invention relates to an on-demand inkjet printhead that forms an inkjet printhead. Specifically, it is widely used in computer output terminals, color printers, etc.

[Conventional technology]

On-demand inkjet printheads can be roughly divided into three types.The first type is equipped with a heater that instantly vaporizes the ink directly below the nozzle or on the wall.
Generates and flies ink droplets by the expansion pressure during vaporization,
The second type is a so-called bubble jet type, and the second type is a type in which a piezoelectric element that deforms in response to a signal is installed in the container that forms the ink reservoir, and the pressure generated during deformation causes ink to fly as droplets.The third type is A piezoelectric element is disposed in the ink reservoir in opposition to the nozzle, and the expansion and contraction of the piezoelectric element generates dynamic pressure in the nozzle area, causing ink droplets to fly.

- The third type of on-demand inkjet print head, as shown in Japanese Patent Publication No. 60-8953, has a plurality of nozzle openings formed on the wall of a container constituting an ink tank. At the same time, piezoelectric elements are disposed so as to face each nozzle opening and extend and contract in the same direction. This print head applies a print signal and a piezoelectric element to extend the piezoelectric element, and the dynamic pressure of the ink generated at this time causes ink droplets to fly out from the nozzle and form a drag on the printing paper. be.

In this type of print head, it is desirable that the droplet formation efficiency and flying force be high. However, the length of the piezoelectric element and the expansion/contraction ratio per unit are extremely small, so in order to obtain the droplet formation efficiency and flying force required for printing, the dynamic pressure of the ink must be concentrated at one nozzle. In addition, it is necessary to apply a high voltage, and there is a problem that the structure, drive circuit, and electrical insulation measures become complicated.

The following proposals have been presented to solve the above problems. First, in order to obtain the droplet formation efficiency and flying force required for printing, the dynamic pressure of the ink is concentrated at the nozzle opening. This is a way to make it bigger. Specifically, a method of providing a step and a horn shape in the thickness direction of a member having a nozzle opening, and a method of providing a step and a horn shape in the thickness direction of a member having a nozzle opening, and a method of providing a step and a horn shape in the thickness direction of a member having a nozzle opening, and a method of providing a step and a horn shape in the thickness direction of a member having a nozzle opening, and a method of providing a step and a horn shape in the thickness direction of a member having a nozzle opening, and a method of providing a step and a horn shape in the thickness direction of a member having a nozzle opening.
Various proposals have been made, including the circular tuna shape shown in Publication No. 3, and a method of protruding the above shape from the ink reservoir side. However, when implementing such a method, the nozzle opening on the ink reservoir side, that is, the inner wall of the container, has to be formed into a complicated shape, so from the viewpoint of processing methods and manufacturing costs, it is necessary to use a separate member from the container. I had no choice. Therefore, by joining a separate member with the above shape to the container, the center of dynamic pressure and the center of the shape of the nozzle opening 1-1 may deviate due to accumulation of 1-method accuracy or deformation. There is a problem that the effectiveness decreases due to tilting or tilting, and there is also a problem that peeling occurs due to environmental conditions and elapsed time conditions in bonding such as adhesives, resulting in extremely poor reliability. be.

In addition, as a method of not applying high voltage to obtain the flying force required for printing, Japanese Patent Publication No. 63-295
As shown in Japanese Patent No. 269, a piezoelectric element for an inkjet print head has been proposed in which electrodes and piezoelectric elements are alternately stacked in a sandwich manner. According to this piezoelectric element, since the distance between the electrodes can be made as small as possible, there is an effect that the voltage of the drive signal can be lowered.

[Problem to be solved by the invention]

However, since it is difficult to mold such a piezoelectric element into a small size, there is a problem that its applications are limited.

It is an object of the present invention to solve the problems described in -.The first object of the present invention is to eliminate the deviation between the dynamic pressure center of the nozzle area and the center of the nozzle opening due to expansion and contraction of the piezoelectric element, Another object of the present invention is to provide a new on-demand ink jet print head which is free from peeling of the nozzle opening member, particularly around the nozzle, and deformation due to peeling, and has stable ink droplet formation and flying power.

A second object of the present invention is to provide a novel on-demand inkjet printhead capable of generating ink droplets with sufficient flying force at the lowest possible voltage.

A third object of the present invention is to provide a compact, high-density, and practical on-demand inkjet printhead.

A fourth object of the present invention is to provide an on-demand inkjet print head that is inexpensive and has excellent mass productivity.

[Means to solve the problem]

The on-demand inkjet print head of the present invention has a piezoelectric plate made of a piezoelectric material and a conductive material cut into pieces with a predetermined width, one pair fixed to or in contact with a base, and the other end set as a free end. an element row and a facing section Iν arranged with a space for forming an ink reservoir facing the free end.
a nozzle member having a part between the nozzles facing the space, and a row partition member disposed between the rows of piezoelectric elements, wherein the nozzle part is arranged between the opposing partition member and the opposing partition member. It is characterized by being formed integrally with.

In addition, the column partitioning member extends so as to partition a space forming the ink reservoir into each piezoelectric element column.

Furthermore, the nozzle member, the opposing partition member, and the row partition member are made of a material that is injected and hardened.

Furthermore, the electric plate t3Q j-1 is characterized in that it is formed by laminating the base 1 piezoelectric material and the conductive material alternately in layers and firing them.

[Effect]

As described above, the on-demand inkjet print head of the present invention, which is C, includes an opposing partition member disposed facing the free end of the piezoelectric element array with a space forming an ink reservoir, and a space forming an ink reservoir. By integrally forming the nozzle member having the nozzle opening part opposite to the row partition member disposed between the rows of piezoelectric elements, deformation and peeling due to conventional bonding can be avoided. There will be no more occurrences. In particular, since the vicinity of the nozzle opening portion is surrounded by the opposing partition member and the row partitioning member as closely as possible, the nozzle opening portion is supported even more firmly, and no deformation or peeling occurs.

In addition, by extending the row partitioning member so as to partition the space forming the ink reservoir for each piezoelectric element row and making it independent,
In addition to further increasing the aforementioned effects, pressure? l! By eliminating the escape and interference of the dynamic pressure on the ink in the direction adjacent to the nozzle opening due to the expansion and contraction of the element, the ion droplet formation efficiency can be increased and the flying force can be increased.

Furthermore, is the piezoelectric element array conductive with pasty piezoelectric material? The piezoelectric plate is made by laminating alternate layers of materials and firing the piezoelectric plates, which are then cut to a predetermined width, so that sufficient flying power can be obtained with a low voltage.

[Example] The details of the present invention will be explained below by way of an example with reference to the drawings.

1 to 5 show the configuration of a first type of on-demand inkjet print head according to the present invention. FIG. 1 is an external perspective view, FIG. 2 is a plan view, and FIG. 3 is a top view. FIG. 2 is a cross-sectional view of the drive section taken along the line AA' in FIG. 2 and centered on the nozzle part. FIG. FIG. 3 is a plan view with the nozzle forming part 7 provided with the nozzle 8 in FIG. 2 removed. Third
In the figure and FIGS. 4 and 5, the piezoelectric element 4 is fixed to the substrate 1 and the housing 2 with a strong adhesive 15. The internal electrodes of the piezoelectric element 4 are alternately formed in a direction facing the cavity 11 so as to vertically vibrate in the direction of the piezoelectric constant d33. External electrodes of the piezoelectric element 4 are formed over the entire upper and lower surfaces, and are electrically connected to lead electrodes 14 formed on the substrate 1'' through an adhesive or a conductive layer 9. Furthermore, the gaps between the rows of piezoelectric elements 4 are filled with a resin material such as an adhesive or filler whose Young's modulus is 20% or less of that of the piezoelectric elements 4, and then hardened to form partition portions b5, which are row partition members. is forming.

Further, the cavity portion is also partitioned with the same material as the partition portion b5, and each piezoelectric element 4 has an independent cavity 11. The side surface of the cavity 11 facing the piezoelectric element 4 forms a partition part a3, which is an opposing partition member, made of the same material as the partition part b5, and is tightly adhered to the substrate 1. Further, the nozzle forming part 7 in which the nozzle 8 facing the cavity 11 is formed has a monthly interest rate equal to that of the partition part b5 on the end surface of the cavity 11, the partition part b5, the piezoelectric element 4, and the housing 2 on the side opposite to the substrate 1 side, respectively. It is formed to a predetermined thickness and size.

The on-demand type inkjet print head according to the present invention having the above-mentioned configuration will be described in detail while following the manufacturing process.

FIG. 6 is a detailed view of the substrate 1. The broken line a in the figure is the line for one unit, so that many pieces can be taken out at the same time.
The head is holding the board 1.

The number of sheets to be taken is determined by the number of nozzles in each head and the O force of the manufacturing equipment. This substrate 1 is made of an insulating material, and a ceramic such as alumina, a glass substrate, or the like is used. Reference numeral 21 denotes a through hole for introducing ink, which is penetrated through the back surface by laser or molding. 22 is a conductive paste for a conductive electrode created by firing a surface electrode], and is generally made of Ag/Pd type, A u / P d type,
A Pt/Pd system is used. Of course, other conductive pastes I can also be used, and the thickness is preferably from 3 μm to 20 μm. The partition block a of 30 and the piezoelectric element block 34 are adhered to this second part with an adhesive of 15.

As the adhesive, a resin adhesive such as an epoxy adhesive or a silicon adhesive is used.

FIG. 7 is a diagram in which 30 partition blocks a and piezoelectric element blocks 34 are bonded to the substrate 1''. The 3° partition block a is formed in advance into a predetermined block shape using a soluble resin for later removal, and then sandwiched between piezoelectric element blocks 34, or by pouring and solidifying resist for the first lithography. It's okay. Next, the partition space 3' portion of the partition block a of 30 is removed, leaving the partition block b of 31 in FIG. 9 with a predetermined thickness. The removal method is to use a dicing saw, wire saw, etc. to remove the partition space 3.
Make a slit with a width of ' and remove. At this time, cutting is performed until the surface of the substrate 1 is exposed. 31 work 9
The J block b is a portion in which a cavity 11 will be formed in the future, and a predetermined thickness necessary for forming the cavity is secured. Also, at this point in FIG. 7, the piezoelectric element block 34 has not been divided into each array, which is a block state diagram. This piezoelectric element block 34 has external electrodes covering the entire surface of each of the upper and lower surfaces.

When fixing the piezoelectric element block 34 to the substrate 1, the end opposite to the cavity 11 side is fixed with a member having a Young's modulus equivalent to that of the high-strength piezoelectric element 4, thereby controlling the amount of expansion and contraction of the piezoelectric element 4. can effectively act on the free end side on the cavity 11 side. Therefore, in this embodiment, the housing 2 is made of a material with a high Young's modulus such as ceramics, and is arranged in close contact with the fixed end of the piezoelectric element 4. In order to further ensure the fixation, it is also possible to use an adhesive with a high Young's modulus between the substrate 1 and the piezoelectric element 4 and between the housing 2 and the piezoelectric element 4 at the portions 6 and 9 in FIG. For example, glass frit material, ceramic paste phase, etc.
It can be fixed by firing or the like in a pre-process to form the partition block a of 0.

Furthermore, the piezoelectric element 4 will be explained in detail.

FIG. 8(a) shows the piezoelectric element block 34, and the reference numeral 40. 40. 40. ...... are conductive layers constituting one electrode, and 42°42
．． 42. . . . are conductive layers constituting the other electrode, and each conductive layer is made of piezoelectric materials 44, 44 . . . alternately parallel to each other. . . . in a sandwich manner, and one electrode 40, 40 . The conductive layers 42, 42 . The conductive layer . Such a layered structure is achieved by forming an appropriate piezoelectric element material, for example, a composite perovskite ceramic material based on titanate/lead zirconate, into a green sheet shape, printing internal electrode material on the surface using a printing method, and printing these sheets alternately. Laminate several sheets.

In this way, a predetermined number of sheets are formed, and pre-drying and sintering are performed to obtain a sintered body. This state is shown in FIG. 8(a). Conductive materials 47 and 48 are applied to the surfaces of this rectangular parallelepiped on which the internal electrodes 42 and 40 are exposed, respectively, and dried or fired to form the structure shown in FIG. 8(b). This is the piezoelectric element block 34, which is ultimately divided into arrays by making slits 46 for use.

The conductor 7 that connects one electrode of each element configured in this way is connected to the layer 47 with an independent lead member, and the conductive layer 48 that connects the electrode on the other side is connected with a common lead. Connect parts. As a result, when an electric signal is applied between an independent lead member and a common lead member, the piezoelectric element to which a signal is selectively applied by the independent lead member can be connected to the same electrode between the electrodes via the conductive layer. Since these voltages are applied at the same time, the piezoelectric material between the electrodes expands simultaneously, and the displacements of each layer are added up, causing the free end side to be displaced in the axial direction. Of course, since each conductive layer is formed extremely thin, an extremely small voltage is required to achieve maximum elongation.

This piezoelectric element block 34 is '4? The agent makes the substrate 1
Top 7! ! It is connected to the pole. There are various conduction methods,
Generally, Ag metal, conductive paste, or conductive adhesive is used. Also, a metal bowl may be pressed between the substrate and the piezoelectric element. The conductive space does not need to be the entire electrode surface, it is sufficient that a certain portion is reliably conductive. However, as mentioned above, since the piezoelectric element block 34 is used by cutting, it is necessary to take care to ensure continuity for each array.

Next, a slint I of a predetermined width is inserted into this state in the direction of the dashed line CC' in FIG. 9 using a dicing saw or a wire saw. At this time, the surface electrode 22 of the substrate 1
Cutting is performed to a depth of 10 to 50 μm from the surface of the substrate 1 so that the substrate 1 is also divided. At this time, 31 partition blocks b are also cut in the same manner as each array of piezoelectric elements 4 with the same slit width. Of course, the pitch may be any desired value. For example, if a head with 300 DPI is to be made, the pitch will be 169.3 μm with 150 DPI on one side.

The housing 2 is installed so as to fit 1 ffl around the piezoelectric element 4 thus cut. The housing 2 is strongly abutted or fixed to the opposite end surface of the substrate 1 and each array of piezoelectric elements 4 on the cavity 11 side. It is desirable that the adhesive used here has as large a Young's modulus as possible.

Then, the electrodes formed on the top surface of the array of each piezoelectric element 4 are made conductive, and the common electrode is taken out. The electrodes on the substrate 1 side and the lower surface of the array of each piezoelectric element 4 are already configured as individual lead electrodes, and the two surfaces are made conductive to the common electrode terminal 13 on the substrate 1 side by using, for example, the outer wall of the housing 2. 1st
Figure 0 shows one example, in which a conductive path is formed on the surface of the housing 2 using conductive paste. In the figure, reference numeral 61 indicates a conductive path on the housing surface, which is electrically connected to the upper surface electrode of the array of piezoelectric elements 4 through a conductive paste 62. Moreover, the conductive path 61
It is electrically connected to the common electrode 13 of the substrate 2 through a conductive paste 63. There are various methods of electrical connection, such as using a flexible cable or wire bonding.

Pressure 71 made by cutting with a dicing saw or wire saw! A slit of a predetermined width between each array of elements 4, a partition space 3', and a nozzle forming part 7 are formed.
- Formed in the body. Figure 11 shows an example of this.
A frame 16 that is thicker than the planned thickness of the nozzle forming part 7 is temporarily attached to the substrate 1 so as to surround the outside of the housing 2, and a predetermined area between each array of the piezoelectric elements 4 described above is attached. The resin material 5 is injected and filled into the wide slit and the partition space 3' up to the height of the -L plane (D+E) of the frame 16 and hardened. The resin-based material 5 is suitably epoxy-based or silicon-based, but there is no need to be particular about this as long as the cured film has appropriate hardness, adhesion, and strength. Next frame 1
6 is removed and the nozzle forming portion 7 is ground to the desired thickness to make it smooth. Grinding is performed using a surface grinder, lapping machine, or dicing saw. Thereafter, the thickness of the nozzle forming part 7 is drilled using a laser or a drill at a predetermined position in the space facing each array of piezoelectric elements 4 of 31 partition blocks b filled with soluble resin to form a cavity 11. Nozzle 8, which is the hole filled with
Drill holes accurately. The accuracy of hole drilling is determined by - For example, the reference hole provided in the substrate 1 or the X-Y of the piezoelectric element block 34 when cutting the piezoelectric element 4 into each array and cutting the partition space 3'. It goes without saying that it is possible to make the end surface, etc., a few micrometers or less by making holes the same.

In addition, the thickness of the nozzle 7 after formation is about 0.05 to 0.5 mm, and transparent grade resin material is used.
By coloring the soluble resin of the 31 partition blocks b filled to form the cavity 11, the partition portions a3, which are injected into the partition space 3' and hardened, are colored in a predetermined manner corresponding to each array of piezoelectric elements 4. It is possible to easily identify the piezoelectric element 4 and the partition part b5, which has been injected into a wide slit and hardened, using an image processing technique or the like. Therefore, it is possible to drill holes in accurate positions without tilting. Further, the frame 16 may be ground at the same time without being removed; in that case, it is necessary to securely bond it to the substrate 1. In this way, the nozzle forming part 7, the partition part a3, and each partition part b5 are made of the same resin material 5.
Since the nozzle openings are injected and cured into one piece, and the vicinity of the nozzle openings are closely surrounded by each other, the nozzle openings are supported very strongly and will not deform or peel. It can also be integrated very easily and with high precision.

In addition, in the above-mentioned cutting, the parts of the substrate 1 corresponding to the partition part a3 and each partition part are cut to the point where the substrate material is exposed, so that the adhesion or adhesion strength with the resin material 5 is high and the reliability is further increased. This will increase the

The soluble resin in the partition block b 31 in FIG. 9, which was filled to form the cavity 11 in the shaft, is removed.

If it is a positive photoresist, it is suitable to remove the carbon with acetone or aqueous ammonia, and if it is a negative photoresist, it is removed by heating and spraying a strong acidic aqueous solution. As a result, a cavity as shown in FIG. 12 can be formed. FIG. 12 shows that the partition block b of 31 is also cut at the same time as the piezoelectric element 4, and the resin material 5 is injected into the space and hardened to form the cavity 11.
This is an example of a state in which the nozzle forming part 7 and the nozzle 8 are removed from the diagram showing the state in which the nozzle forming part 7 and the nozzle 8 are formed.

In this embodiment, a method has been described in which the cavities 11 are opposed to each other with the partition part a3 in between, but of course, the nozzle openings may be arranged in one row, or it is also easy to have multiple rows.

The print head configured in this manner is configured such that when an electrical signal is applied to the piezoelectric element 4 via the cable 12, the piezoelectric element 4.
4. 4. Since . As a result, the ink enters the nozzle opening 8 under dynamic pressure, becomes an ink droplet, flies in the external space, and forms a dot on the printing paper.

When the electric signal is no longer applied, the piezoelectric element shrinks to its original state, and ink flows into the gap between the partition part 3 and the piezoelectric element 4 to prepare for the generation of ink droplets.

Incidentally, ink for inkjet printers may be insulative or conductive.

Particularly when using conductive ink, the electrodes of the piezoelectric element must be completely sealed from the ink. In order to solve this problem, it is desirable to form a layer that does not take part in the piezoelectric action on both free holes, such as the first layer shown in FIG. 13, using a pressure WL material.

Furthermore, it is also a good method to dip the entire piezoelectric array in an insulating resin solution, for example, a polyimide solution, and coat the surface of the piezoelectric element with a thin insulating film before pouring the partition part b5 between the slits.

In addition, in the embodiments described above, the common electrode is taken out first, and then the nozzle forming part 7, the partition part a3, and the partition part b5 corresponding to each array of piezoelectric elements 4 are simultaneously injected with resin material. Although the method of filling, curing, and integrally forming the material has been described, the method is not limited to this method. For example, a method may be adopted in which the partition portion a3 and the partition portion b5 are first formed integrally, and then the common electrode is taken out, and then the nozzle forming portion 7 is formed and integrated.

Furthermore, FIG. 14 shows an embodiment of ¥32 in which the resin-based material that is the partition member of each cavity does not extend to the partition part a3. Since the first embodiment is a high-density head, there is a problem of crosstalk.

This embodiment is relatively effective when the density of adjacent nozzle openings is not high, and is sufficiently practical. The figure shows the nozzle forming part 7 as transparent, and the space between the piezoelectric elements is filled with a partition part b5. In the figure, reference numeral 3 denotes a partition part a that partitions the piezoelectric element rows. In the case of this embodiment, the partition block b7f of 31 in FIG. 9! : It is not necessary to provide the piezoelectric blocks 34. After adhering each piezoelectric block body 34 at a predetermined distance and filling the space between the rows of piezoelectric elements and the partition with resin, the space corresponding to 31 is cut with a dicing saw, etc., and a soluble resist is can be injected and solidified to form a cavity.

FIG. 14 71 shows the gap formed in this manner.

〔Effect of the invention〕

As described above, according to the present invention, by integrally forming the nozzle forming part, the row partition member, and the opposing partition member, displacement, deformation, peeling, etc. are eliminated, and especially in the nozzle opening 1-1 part. Since the vicinity of the ink droplet is more firmly supported by members made of the same material, it is possible to obtain extremely high reliability and stable ink droplet formation under temperature and time conditions, and a large flying force.

Further, by using a material that is injected and filled with the above-mentioned members and hardened, it can be formed very easily and with high precision and in a short time.

Furthermore, by utilizing vibration in the d33 direction of the laminated piezoelectric element, ink droplets with sufficient flying force can be generated with a low voltage. The voltage can be lowered as the number of laminated layers increases.

Furthermore, the manufacturing method of the present invention allows for simultaneous production of many inkjet heads, making it possible to manufacture very inexpensive inkjet heads, and is also superior in high density and high reliability, resulting in miniaturization and low cost. It is clear that this is an extremely effective invention that can simultaneously realize the following functions.

[Brief explanation of the drawing]

1 to 5 show the configuration of a first type of on-demand infusiera 1-type print head according to the present invention, and FIG. 1 is an external perspective view. Figure 2 is a plan view. FIG. 3 is a cross-sectional view of the drive section taken along the line AA' in FIG. 2 and centered on the nozzle section. FIG. 4 is a sectional view taken along the line BB' in FIG. 2 and centered around the partition. FIG. 5 is a plan view with the nozzle forming part 7 provided with the nozzle 8 in FIG. 2 removed. 6 to 11 are diagrams related to the manufacturing process according to the present invention, and FIG. 6 is a detailed diagram of the substrate. Figure 7 is a diagram showing a partition block and a piezoelectric element block bonded to a substrate. FIG. 8(a) is a state diagram of a sintered body of a piezoelectric element block. FIG. 8(b) is a state diagram of the piezoelectric element block with external electrodes attached. FIG. 9 is a state diagram of dividing and cutting a piezoelectric element block. FIG. 10 is a diagram showing an example of a state in which the common electrode is taken out. FIG. 11 is a diagram showing an example of a state in which the nozzle is formed integrally with the nozzle forming part. FIG. 12 is a diagram showing an example of a state in which a cavity is formed. ¥413 The figure shows an example of the structure of a piezoelectric element for insulation sealing. FIG. 14 is a diagram showing another embodiment in which the partition member of the cavity does not extend to the partition portion. 1... Substrate 2... Housing 3... Partition part a 4... Piezoelectric element 5... Partition part b 7... Nozzle forming part 8... Nozzle 11... Cavity 12...・More than cables Applicant Seiko Epson Co., Ltd. agent Patent attorney Kisanbu Meiki and 1 other person Hehe~Hehehe to the rumor place (b) Figure 9 34: Pressure Oki Hemi Pro...

Claims (4)

[Claims] (1) A piezoelectric plate made of a piezoelectric material and a conductive material is cut to a predetermined width, one end is fixed to or in contact with a base, and the other end is arranged as a free end, and a row of piezoelectric elements is arranged opposite to the free end. a nozzle member having a nozzle opening facing the space; and a row partition member disposed between the rows of piezoelectric elements; An on-demand inkjet print head, characterized in that the on-demand inkjet print head is formed integrally with the opposing partition member and the row partition member. (2) The on-demand inkjet print head according to claim 1, wherein the row partition member extends so as to partition the space forming the ink reservoir for each row of piezoelectric elements. (3) The on-demand inkjet print head according to claim 1 or 2, wherein the nozzle member, the opposing partition member, and the row partition member are made of a material that can be injected and cured. (4) The on-demand inkjet print head according to claim 1, wherein the piezoelectric plate is formed by laminating and firing paste-like piezoelectric material and conductive material alternately in layers.