JPH09164672A - Ink jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent interlocking displacement caused by deformation of piezoelectric members by forming rigid protruded streaks on the back faces of the piezoelectric members which displace an ink in an ink channel. SOLUTION: An electrode 26b on a rear face of each of piezoelectric members 25a and 25b is grounded. Each of them applies negative voltage to an electrode 26a at an ink channel-side. Then, in the first and second piezoelectric bodies 25a and 25b electric fields are formed in directions of arrows E1 and E2 and deformed into forms shown by broken lines 42a and 42b. At this time, respective rear faces of the piezoelectric bodies 25a and 25b are made to be protruded streaks 23, which do not give influence of the deformation to an ink channel 16. As a result, the volume of the ink channel 16 rapidly reduces and an ink which is filling the ink channel 16 is pressed and discharged from a nozzle hole. Next, when the application of voltage is completed, both the first and second piezoelectric bodies 25a and 25b return to original states shown by solid lines 41a and 41b. At this time, the pressure is reduced by expansion of the volume in the ink channel 16 and an ink of the discharged quantity is supplied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus for ejecting ink droplets according to an image signal to record on a recording medium such as paper.

[0002]

2. Description of the Related Art Currently, among non-impact printers capable of quiet and high-density printing, an ink jet printer which ejects ink from a nozzle hole and fixes it on a sheet has been put into practical use. Among them, the piezoelectric element is used to change the volume of the ink channel communicated with the nozzle hole by its dimensional displacement, eject the ink in the ink chamber when the volume decreases, and introduce the ink into the ink channel when the volume increases. In this way, a drop-on-demand inkjet printer has been proposed in which a voltage is applied to a piezoelectric element in accordance with an image signal to deform the piezoelectric element for printing.

As an example of the ink jet head for ejecting the ink as described above, the one shown in FIG. 8 is disclosed in JP-A-6-143564. In this ink jet head 60, piezoelectric element strips 63 are arranged between support substrates 61 and 62 at a predetermined pitch in the direction of arrow D ₆ so that the piezoelectric element strips 63 are arranged in a space defined by the support substrate and the piezoelectric element strips 63. Is a channel. The channels are the ink channel 64 and the dummy channel 65 in order. Then, electrodes 66 are formed on both side surfaces of the piezoelectric element strips 63 facing the channel, and a voltage is applied to the electrodes to cause the piezoelectric element strips to deform in the expansion / contraction mode to eject ink from the ink channel 64. Let When the piezoelectric element 63 that hits the side wall of the specific ink channel 64 is deformed and ink is ejected, the deformation of the piezoelectric element also affects the channels on both sides of the specific ink channel.
Is provided. The dummy channel is filled with a void or an elastic member. This presence eliminates the influence of the deformation of the piezoelectric element 63 on the adjacent ink channel 64.

[0004]

However, in the ink jet head, the space partitioned by the piezoelectric element strips is repeated in the order of the ink channel, the dummy channel, and the ink channel, so that the pitch between the ink channels increases. In addition, the pitch of the nozzle holes communicating with the ink channels is also enlarged, and it has been difficult to increase the density of the nozzles for high resolution printing.

Further, when the piezoelectric element is driven to eject ink, part of the force that deforms the piezoelectric element and displaces the ink in the ink channel escapes to the dummy channel, which is inefficient. Further, the ratio of the force escaping to the dummy channel when it is deformed is not always constant, and its control is extremely difficult especially when performing multi-tone printing. Therefore, it is an object of the present invention to provide an ink jet recording apparatus in which nozzles can be arranged at a high density, the adjacent ink channels are not affected by deformation, can be efficiently driven, and can be easily controlled.

[0006]

In order to solve the above-mentioned problems, an ink jet recording apparatus of the present invention comprises a first substrate made of a rigid body having a plurality of ridges, and the ridges of the first substrate. Forming an ink channel between a piezoelectric member that is disposed along the side wall of the piezoelectric member and that is deformed by applying a voltage, and that is fixed in parallel with the first substrate and that is adjacent to the first substrate. It has two substrates and a power source for applying a voltage to the piezoelectric member in order to change the volume of the ink channel and displace the ink in the ink channel to eject the ink.

According to this ink jet recording apparatus, since the back surface of the piezoelectric member is a rigid protrusion when the piezoelectric member is deformed to eject ink, a dummy channel is provided between the ink channels. It is possible to prevent interlocking displacement due to deformation of the piezoelectric member,
The pitch of the nozzles communicating with the ink channels can be made fine and high density. Also, when the piezoelectric member is deformed and ink is ejected, the back surface of the piezoelectric member is a rigid ridge, so the pressing force of the ink due to the deformation does not escape to the outside of the ink channel and can be used effectively. You can

The second substrate may be fixed to the upper surface of the protrusion of the first substrate. In this case, the first substrate and the second substrate are securely attached to each other, and the rigidity is increased, so that the vibration due to the deformation of the piezoelectric member at the time of ink ejection is further difficult to be transmitted, which is extremely effective in preventing the interlocking displacement.

Further, the piezoelectric member is arranged so as to be polarized in a direction toward the ink channel, and has electrodes on a surface facing the ink channel and a surface facing the ridge, and the power supply means is polarized in the polarization direction. The voltage may be applied so that an electric field is generated in the same direction as. By arranging in this way, compared with the case where the piezoelectric member is driven under the same conditions, the volume change of the ink channel is large and the piezoelectric member can be used efficiently.

Furthermore, the second substrate may be formed of a piezoelectric material. In this case, not only the side surface forming the ink channel but also one surface of the substrate can be deformed, so that the working surface becomes large and the volume change of the ink channel can be made large. Further, since the working surface can be increased, it is possible to drive at a low voltage. Furthermore, whether to deform one side or two sides, 3
Depending on whether the surface is deformed, the ink ejection amount can be adjusted in three stages, and gradation expression can be performed.

In addition, in the piezoelectric body that deforms the volume of the ink channel, the volume change of the ink channel when a predetermined voltage is applied may be different at each deformed portion. In this case, it is possible to change the ink ejection amount for each working surface, and even if only ON / OFF control is performed for each working surface, it is possible to give 7 different kinds of changes in the ejection amount. This is particularly effective when printing gradations.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 schematically shows the overall configuration of an inkjet recording apparatus 1 equipped with an inkjet head 12 according to a first embodiment of the present invention. The inkjet recording apparatus 1 is roughly classified into a power source section 2 having a connector 2a, a drive system 3, a mechanical controller 4, a memory 5, a controller 6, and
Ink supply unit 7, scan carriage 8, paper feed unit 9
And a case 10 and an operation panel 11. The scan carriage 8 is capable of scanning in a direction (front and back direction of the drawing in FIG. 1) orthogonal to the sheet passing direction (arrow a direction), and inside thereof, black, cyan, magenta, and yellow colors are provided. Four ink jet heads 12 are arranged along the paper feeding direction for
It is arranged with 3 facing downward.

As shown in FIG. 2, the ink jet head 12 has a top plate 14 made of a non-piezoelectric member corresponding to the second substrate on the upper surface thereof, and a non-piezoelectric member corresponding to the first substrate on the lower surface thereof. The substrate 15 is provided with a ridge portion 23 described later. The top plate 14 and the substrate 15 are units that form the skeleton of the ink channel and are made of a rigid body. Desirably, it is an insulating material having a Young's modulus of 1.5 × 10 ⁹ N / m ² or more. In this embodiment,
The top plate 14 is a plate of alumina (Al ₂ O ₃ ) which is a non-piezoelectric member, and the substrate 15 is a non-conductive member of Steatite which is a product of Noritake Co. . A plurality of ink channels 16 are formed between the top plate 14 and the substrate 15 by partition walls 24 as shown in FIG. As shown in FIG. 3, these ink channels 16 are formed at a predetermined pitch in the width direction of the top plate 14 and extend in parallel with the longitudinal direction of the top plate 14 shown in FIG.

A nozzle plate 17 having nozzle holes 13 formed at positions corresponding to the respective ink channels 16 is adhesively fixed to the front surface of the ink jet head 12.
Further, the back plate 18 is adhesively fixed to the top plate 14 and the rear end side surface of the substrate 15. The back plate 18
An ink manifold 19 is provided behind the
An ink supply path 20 is connected to the ink supply unit 7 shown in FIG. The back plate 18 is provided with an ink supply port 21 for supplying ink from the ink manifold 19 to the ink channel 16. Partition part 2
A wiring 22 connected to an electrode 26, which will be described later, for deforming the piezoelectric body 25 of No. 4 is printed on the substrate 15 and is drawn out to the outside behind the back plate 18. An ink jet head 12 having such an ink channel 16 as a constituent element is provided for each color, and each of the supporting substrates 2 is provided.
It is fixedly held on top of No. 8.

As shown in FIG. 3, the partition wall portion 24 is formed on the upper surface of the substrate 15 in the form of a ridge in the front and back direction of the paper, and is arranged on both sides of the ridge portion 23. It is composed of two piezoelectric bodies 25a and 25b. The piezoelectric body 25
Reference symbols a and 25b are made of lead zirconate titanate (abbreviated as PZT), and the polarization direction thereof is parallel to the top plate 14 and the substrate 15 shown by arrows D ₁ and D ₂ in FIG. Are arranged as follows. The ink channel 1 is provided in the piezoelectric bodies 25a and 25b which are piezoelectric members.
6, the surface electrode 26a and the ridge 2 provided on the surface facing 6
3 is provided with an electrode 26 including a back electrode 26b provided on the surface facing the No. 3 electrode.

The adhesion between the substrate 15 and the top plate 14 is
Since it serves as the skeleton of the inkjet head 12 and plays an important role in preventing interlocking displacement, it is securely fixed at both end portions (not shown). Further, the upper surface 30 of the ridge 23 of the substrate 15 and the lower surface of the top plate 14 are bonded and fixed,
In addition to increasing the overall rigidity, the rigidity of the protrusion 23 itself is also increased. The piezoelectric bodies 25a and 25b are not firmly bonded to prevent their displacement. More specifically, a low-elasticity sealant is provided between the piezoelectric bodies 25a and 25b and the surrounding substrate 15, the top plate 14, the nozzle plate 17 and the back plate 18, which will be described later, in order to prevent ink from wrapping around. For example, nitrile 54 of Cemedine Co., Ltd.
0 (elastomer adhesive) is filled, or elastic adhesion is performed with a flexible adhesive. In this embodiment, a flexible adhesive, for example, E30H adhesive manufactured by Konishi Co., Ltd., is used to bond the adhesive layer 27 having a thickness of about 25 μm. As described above, the top plate 14, the substrate 15 having the protrusions 23, and the piezoelectric body 25 having the electrodes 26 are provided.
A head unit including a and 25b is configured.

[0017] Here, in the present embodiment, the polarization direction D ₁ of the first piezoelectric 25a, and the polarization direction D ₂ of the second piezoelectric 25b, is inverted 180 degrees as shown in FIG. Are arranged. By arranging the piezoelectric bodies 25a and 25b in this manner, the second piezoelectric body 25 adjacent to the back electrode 26b of the first piezoelectric body 25a via the protrusion 23 is formed.
It is possible to make them equipotential (common) by connecting the back electrode 26b of b. Even if the back electrode is shared (for example, grounded), the displacement of each piezoelectric body 25 can be controlled by controlling only the surface electrode 26a on the ink channel 16 side. Also, the back electrode 26b
The number of wirings can be reduced and the wirings can be made thicker than the case where wirings are separately provided.

The substrate 15, the top plate 14, and the piezoelectric body 2 are also provided.
An insulating overcoat treatment is applied to a portion of the surface of the ink channel 16 including the electrodes 5a and 25b and the electrode 26a that is in direct contact with the ink. This allows
While the durability of the electrode 26a is improved, the ink penetrates into the piezoelectric bodies 25a and 25b of the partition wall portion 24 to reduce the resistance,
The inconvenience that the effective voltage is not applied and the deformation amount is reduced is prevented. Furthermore, even if the non-insulating ink is used, the piezoelectric bodies 25a and 25b can be individually controlled without having the same potential inside the channel. In other words, non-insulating ink can also be used. In this overcoat treatment, a resin is applied or sprayed, or an inorganic substance is attached by sputtering or CVD.

Next, with reference to FIG. 4, the operation of ejecting ink from the ink channel 16 will be described. For simplicity of explanation, one of the multi-channels is used here.
Only the operation of one channel is shown, but the same applies to the other ink channels 16. The first piezoelectric body 25a before applying a voltage is shown by a solid line 41a, and the second piezoelectric body 25b is shown by a solid line 41b. The polarization direction of the first piezoelectric body 25a is the direction shown by arrow D ₁ in the figure, and the polarization direction of the second piezoelectric body 25b is the direction shown by arrow D ₂ in the figure.

The electrodes 26b on the back surface of each of the piezoelectric bodies 25a and 25b are grounded, and the electrodes 2 on the ink channel side are respectively connected.
A negative voltage is applied to 6a. Then, the first piezoelectric body 25
In a, an electric field is formed in the direction of arrow E ₁ and a broken line 42
It deforms in the shape indicated by a in the expansion / contraction mode (d33 mode) in the thickness direction. An electric field is also formed in the direction of arrow E _{2 in} the second piezoelectric body, and the second piezoelectric body is deformed into the shape shown by the broken line 42b in the figure. At this time,
The back surface of each piezoelectric body 25a, 25b is a ridge portion 23 having rigidity, and the adjacent ink channel 16
Does not affect the deformation. In addition, the piezoelectric bodies 25a, 25
All of the deformation amount of b can be used for the reduction of the volume of the ink channel 16, which is very efficient.

As a result, the volume of the ink channel 16 is rapidly reduced, the ink filled in the ink channel 16 is pressurized, and an ink droplet is ejected from the nozzle hole 13. In the present embodiment, the piezoelectric bodies 25a and 25b and the top plate 1
4, the space between the substrate 15 and the space between the piezoelectric bodies 25a and 25b and the nozzle plate 17 and the back plate 18 is filled with the elastic adhesive having flexibility described above, and the ink wraps around to the side surface even when the piezoelectric body extends. Is regulated. Therefore, ink loss can be efficiently ejected with little pressure loss.

Next, when the voltage application is completed, the first piezoelectric body 25a and the second piezoelectric body 25b are broken lines 42a and 42b.
The state shown by is returned to the state shown by the original solid lines 41a and 41b. At this time, the pressure in the ink channel 16 is reduced due to the expansion of the volume, and the ink is supplied from the ink supply port 21 in an amount commensurate with this, that is, in the ejected amount. As described above, by applying ON / OFF of the voltage to the piezoelectric bodies 25a and 25b of each ink channel 16 with a combination of prescribed pulse waves according to the printing content, printing by multi-nozzle becomes possible.

In this embodiment, the substrate 15 and the top plate 14 are securely fixed at both ends of the ink jet head, and the upper surface 30 of the ridge 23 and the top plate 14 are fixed.
However, the upper surface 3 of the protrusion 23 is not always
It is not necessary to bond 0 and the top plate 14. However, it is desirable to bond the ridge 23 and the top plate 14 from the viewpoint of preventing interlocking displacement. Further, the protrusion 23 and the top plate 14 may not be in contact with each other. When the protrusion 23 and the top plate 14 are not adhered to each other, the ink channels 16 should be sealed by securely adhering the piezoelectric bodies 25a and 25b to the top plate 14, the substrate 15, etc. with an elastic adhesive or the like. Is.

Next, a method of manufacturing the ink jet head 12 will be described with reference to FIGS. FIG. 5 shows the first manufacturing method. First, as shown in FIG. 5A, the above-mentioned elastic adhesive is applied to the top plate 14 made of alumina or the like so as to have a predetermined thickness (about 25 μm), and the adhesive layer 27 is provided. Then, a piezoelectric body 25 having a polarization direction in the direction of arrow D is attached thereon and integrated to form a component 32. Here, the length of the top plate 14 is the ink channel 16
1/2, that is, the length of the top plate in the direction orthogonal to the polarization direction of the piezoelectric body 25 is 1/2 of the piezoelectric body 25.

Next, the component 32 shown in FIG. 5 (a) is cut with a cutting means such as a dicer to form an adhesive layer 27 with the piezoelectric body 25 and the top plate 14 in a shape as shown in FIG. 5 (b). Piezoelectric body 2 that is a piezoelectric body that is cut along a straight line
5 are individually made into a ridge shape to form a part 33. At this time, the cutting width for cutting the piezoelectric body 25 is the total length of the width of the ink channel 16, the thickness of the independent first piezoelectric body 25a, the thickness of the second piezoelectric body 25b, and the thickness of the protrusion 23. Is.

Subsequently, the electrode 26 is attached to the independent piezoelectric body 25 of the component 33 shown in FIG. 5 (b). First, the top plate 1
Masking is applied to 4 parts. An Au or (Ni, Cr) film is attached to the surface of the top plate 25 on which the piezoelectric body 25 is attached and the projections and depressions are formed by sputtering or plating. Thereafter, the front surface portion and the rear surface portion of the independent piezoelectric body 25, that is, the nozzle plate 17 and the back plate 1 are separated.
The surface of the piezoelectric body 25 to which 8 is adhered and the electrode portion 26 formed by sputtering or the like on the upper surface portion 30 of the piezoelectric body 25,
The metal film part is removed by polishing or cutting.

In this way, two comb-tooth-shaped parts to which the electrodes 26 are attached are formed, and one of the parts is rotated 180 degrees about the normal line direction of the top plate 14 as shown in FIG. 5 (c). As shown, the piezoelectric members 25 protruding in a comb shape so that the number of the top plates 14 is one are fitted and joined to each other, and the integrated component 31 is formed.
Create When joining the two parts 33 in this way,
In order to prevent ink from leaking from the connecting portion and to increase the rigidity, the top plates 14 are particularly firmly bonded to each other. Further, the piezoelectric body 25 of the one component 33 and the top plate 14 of the other component 33 are bonded by the elastic adhesive described above so as not to restrict the deformation.

When the two parts 33 are bonded together, the starting points of the polarization directions D ₁ and D ₂ of the piezoelectric bodies 25a and 25b formed of the cut piezoelectric body 25 (the sides not facing the arrows) face each other. The ridge 23 is fitted in the space.
On the other hand, the ink channel 16 is a space in which the end points of the polarization directions D ₁ and D ₂ of the piezoelectric bodies 25a and 25b (the sides where the arrows point) face each other. Therefore, when joining the two comb-teeth-shaped components, they should be positioned and joined so that an appropriate interval can be obtained. As described above, as shown in the perspective view of FIG. 5 (c), the integrated component 31 in which the piezoelectric bodies 25a and 25b having the electrodes 26 on both surfaces thereof and the top plate 14 are integrated is prepared. To do.

On the other hand, as shown in FIG. 5D, the substrate 15 is formed by scraping off the above-mentioned steatite flat plate of the Noritake Co. product leaving the ridge 23. Specifically, the steatite plate is used as the ink channel 16.
Then, the widths of the piezoelectric bodies 25a and 25b are shaved in a straight groove shape with a dicer, and the widths of the ink channels 16 and the piezoelectric bodies 25a and 25b are shaved again at intervals of the protrusions 23. Similarly, this operation is repeated to form the substrate 15 having a comb-shaped cross section with the protrusion 23 protruding from the upper surface. The wiring 22 described above is printed on the substrate 15.

The upper surface 30 of the protrusion 23 and the top plate 14 are bonded by fitting the substrate 15 to the integrated component 31, and the integrated component 31 and the substrate including the top plate 14 at both ends (not shown). 15 is firmly fixed. Further, the upper surface portions 30 of the piezoelectric bodies 25a and 25b and the substrate 15 are adhered to each other with the adhesive layer 27 having the width of the adhesive layer 27 to form the ink channel 16 having the cross section shown in FIG. Then, each electrode 26 is connected to the wiring 22 by a method such as wire bonding and drawn out to the outside, and the nozzle plate 17
Then, the back plate 18 and the ink supply path 20 are attached to form the inkjet head 12.

At this time, it is not necessary to bond the surfaces of the piezoelectric bodies 25a and 25b where the back electrodes 26b and the ridges 23 come into contact with each other. In addition, between the piezoelectric bodies 25a and 25b and the substrate 15, the nozzle plate 17, the back plate 1
A space between 8 and 8 may be filled with a low-elasticity sealant instead of being bonded with an elastic adhesive. Furthermore, the inside of the ink channel 16 may be overcoated when the integrated component 31 and the substrate 15 are fitted and bonded. By overcoating, it is possible to prevent the electrode 26 from being corroded by the ink and the ink from penetrating into the piezoelectric bodies 25a and 25b, and the durability is improved. When an insulating overcoat is applied, both piezoelectric bodies 25 of the ink channel 16
When a and 25b are driven independently, it is particularly effective because the surface electrodes 26a of each do not become conductive and become equipotential.

As described above, the top plate 14 shown in FIG.
Integrated component 3 in which the piezoelectric body 25a and the piezoelectric body 25b are integrated
By using 1 to reduce the number of parts during assembly,
The ridge portion 2 of the substrate 15 is individually provided for each ink channel 16.
Piezoelectric bodies 25a, 25b having electrodes 26 formed on both sides of 3
Assembleability is significantly improved as compared with the case of arranging. The multi-ink channel shown in FIG. 2 can be easily formed by fitting and adhering the top plate 14-piezoelectric body 25a, 25b integrated component 31 and the substrate 15 having the protrusion 23.

FIG. 6 shows a second manufacturing method different from the first manufacturing method. In the first manufacturing method, the polarization directions D ₁ and D ₂ of the piezoelectric bodies 25a and 25b on both sides of the ink channel 16 are both directed toward the ink channel 16. However, the polarization direction of the piezoelectric bodies 25a and 25b does not always have to be the ink channel direction. Therefore, as shown in FIG. 6A, the piezoelectric body 25 whose polarization direction is indicated by the arrow D in the drawing and the top plate 14 whose bonding surface has substantially the same size as the piezoelectric body are processed in the same manner as described above. An adhesive layer 27 is provided and adhered.

As shown in FIG. 6B, the piezoelectric body 25 including the adhesive layer 27 is cut into a groove shape from the adhered parts by using a dicer or the like. At this time, the piezoelectric body 25 is cut so that the width of the ink channel 16 and the width corresponding to the protrusion 23 are cut alternately. Further, the electrode 36
Is attached to the piezoelectric body 25 to form a part in which the top plate 14 and the piezoelectric body 25 are integrated. Further, similarly to the above, the substrate 15 having the protrusion 23 projected on the upper surface is formed by cutting,
When this substrate 15 is fitted and adhered to a component in which the top plate 14 and the piezoelectric body 25 are integrated, a head unit whose cross section is shown in FIG. 6C is formed. Further, the head unit is overcoated inside the ink channel 16 to insulate the surface electrode 36a of the ink channel, and wiring is provided from each electrode to the outside.
The back plate 18 and the like are attached to form the inkjet head 12.

In this case, compared with the method shown in FIG. 5, the number of manufacturing steps is reduced and the manufacturing is easy. However, in this case, it is necessary to make an insulating overcoat in the ink channel 16, or it is necessary to limit the use to an insulating ink. Because the polarization directions of the piezoelectric bodies 25c are the same, when applying a voltage to the opposing surface electrodes 36a in the ink channel 16,
This is to prevent the inconvenience that the potential inside the ink channel 16 becomes the same potential and the piezoelectric body 25c does not displace.

FIG. 7 shows the configuration of another embodiment. 4 is a schematic cross-sectional view corresponding to FIG. 4 of the first embodiment and focusing on one ink channel 16. The difference from the first embodiment is that the top plate 14 is also configured by using a piezoelectric body R which is a polarized piezoelectric member. As a result, in this embodiment, the three wall surfaces of the upper surface and the left and right sides can be used as drive sources for ink ejection, and the volume change amount of the ink channel 16 can be further increased. Further, by positively utilizing this advantage, it becomes possible to control the change of the volume in the ink channel 16 in multiple stages.

Therefore, according to this embodiment, it becomes easy to control the ejection amount of the ink, which has a high accuracy required for multi-tone printing and affects reproducibility, in multiple stages. One ink channel 16 has three piezoelectrics P, Q, R for this embodiment. By combining ON / OFF of the three piezoelectric bodies P, Q, and R in the one ink channel 16, the ink channel 16 can be easily changed by intentionally changing the volume change amount of each of the piezoelectric bodies P, Q, and R. It is possible to carry out multi-step control of the volume amount inside, and select 8 types of volume change amounts (including no change) in 2 × 2 × 2.

Next, a method of controlling volume changes in multiple stages will be briefly described. It is assumed that the three piezoelectric bodies P, Q, R forming the side wall of the ink channel 16 are displaced by p, q, r (μm) by applying a predetermined voltage to the electrode 26. In addition, the acting area of each piezoelectric body is set to T ₁ , T ₂ , T
₃ (μm ² ) From the above, the volume change amount of each piezoelectric body P, Q, R in the ink channel 16 is pT ₁ , q
T ₂ and rT ₃ (μm ³ ). The respective volume change values are intentionally adjusted to different values.

As a method of varying the volume change amount, p
It is conceivable to change the displacement amount of ~ r, change the working area of T _{1 to} T ₃ , or combine them.
The displacement amount is changed by changing the voltage applied to the electrode 26 or changing the composition of the piezoelectric bodies P, Q, and R. Since P and Q have the same composition, p = q if the applied voltages are the same. However, even if the applied voltage from the power source 2 is the same, it is possible to add resistance or the like to make the applied voltages applied to the respective piezoelectric bodies P and Q different so that p ≠ q. The change of the active area can be adjusted by changing the channel size and the area of the electrode 26. With the above, it is possible to perform control in eight steps including no ejection. Further, if three types of displacements are realized by one piezoelectric body, theoretically, 3 ³ 27 gradations can be expressed.

[0040]

As described above, according to the ink jet recording apparatus of the present invention, since the rigid ridge is formed on the back surface of the piezoelectric member that displaces the ink in the ink channel, the gap between the ink channel and the ink channel is formed. It is possible to prevent interlocking displacement due to deformation of the piezoelectric member without providing a dummy channel, and it is possible to make the pitch of the nozzles communicating with the ink channels fine and high density. Further, when the piezoelectric member is deformed and ink is ejected, there is a rigid ridge on the back surface of the piezoelectric member, so that the pressing force of the ink due to the deformation does not escape to the dummy channel and can be effectively used. You can

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an inkjet recording apparatus using an inkjet head of the present invention.

FIG. 2 is a cross-sectional view in the width direction of the inkjet head according to the first embodiment.

FIG. 3 is a side sectional view in the longitudinal direction of the main part of the inkjet head according to the first embodiment.

FIG. 4 is an operation explanatory diagram using a cross section in the width direction of the inkjet head according to the first embodiment.

FIG. 5 is a diagram showing a method of manufacturing an integrated component including a top plate, a substrate, and a piezoelectric body of the inkjet head according to the first embodiment, and FIG. 5A is a diagram in which the piezoelectric body is bonded to the top plate. 2B is a diagram in which the piezoelectric body is cut.
FIG. 6C is a perspective view of a top plate-integrated component in which a piezoelectric body having a polarization direction reversed is attached in a strip shape. (D)
FIG. 4 is a diagram of a processed substrate.

FIG. 6 is a diagram showing a method of processing an integrated component of a top plate and a piezoelectric body of an inkjet head according to another embodiment, FIG. 6A is a diagram in which the piezoelectric body is bonded to the top plate, and FIG.
[Fig. 6] is a view in which a piezoelectric body is cut, and (c) is a cross-sectional view of essential parts in the width direction of an inkjet head unit of another embodiment.

FIG. 7 is a cross-sectional view of a portion in the width direction of an inkjet head component according to still another embodiment.

FIG. 8 is a cross-sectional view of a main part of a conventional inkjet head in the width direction.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Inkjet recording device, 2 ... Power supply, 12 ... Inkjet head, 13 ... Nozzle, 14 ... Top plate (2nd substrate), 15 ... Substrate (1st substrate) 16 ... Ink channel, 23 ... Ridge part, 25a ... Piezoelectric body (piezoelectric member), 25
b ... Piezoelectric body (piezoelectric member), 26 ... Electrode.

Claims (5)

[Claims] 1. A first substrate made of a rigid body having a plurality of protrusions formed thereon, and a piezoelectric member disposed along a side wall of the protrusions of the first substrate and deformable by applying a voltage. A second substrate fixed in parallel with the first substrate and forming an ink channel between the first substrate and a piezoelectric member facing each other; and an ink in the ink channel for changing a volume of the ink channel. And an electric power source for applying a voltage to the piezoelectric member in order to displace ink and eject ink. 2. The ink jet recording apparatus according to claim 1, wherein the second substrate is fixed to the upper surface of the protrusion of the first substrate. 3. The piezoelectric member is arranged so as to be polarized in a direction toward the ink channel, and has electrodes on a surface facing the ink channel and a surface facing the ridge portion, and the power supply unit is polarized in a polarization direction. The ink jet recording apparatus according to claim 1 or 2, wherein a voltage is applied so that an electric field is generated in the same direction as. 4. The ink jet recording apparatus according to claim 1, wherein the second substrate is composed of a piezoelectric member that is deformed by applying a voltage. 5. The ink jet recording apparatus according to claim 1, wherein the piezoelectric member that deforms the volume of the ink channel has a volume change that is different for each member when a predetermined voltage is applied.