JP2721127B2 - Inkjet head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

(Contents) Industrial application field Conventional technology (FIGS. 43 to 44) Problems to be Solved by the Invention Means for Solving the Problems (FIG. 1) Action Embodiment (a) Description of Inkjet Head ( 2 to 16) (b) Description of multi-nozzle head (FIGS. 17 to 42) (c) Description of other embodiments Effect of the Invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head for ejecting ink by applying pressure to a pressure chamber containing ink.

[0003] Image forming apparatuses such as copiers, printers, and facsimile machines are widely used. In such an apparatus, an ink jet printer is used because of its simple configuration. In this ink jet printer, an ink is ejected from an ink jet head to form an image on a recording medium.

[0004] Among these ink jet heads, those that apply pressure to ink in a pressure chamber to eject ink are used. In this type, it is desired that the conversion efficiency of the applied pressure into ink ejection be good.

[0005]

2. Description of the Related Art FIGS. 43 (A) and 43 (B) are explanatory diagrams of a first prior art, and FIGS. 44 (A) and 44 (B) are second diagrams.
It is explanatory drawing of the prior art of FIG.

As shown in FIG. 43A, the pressure chamber 2 is filled with ink. The nozzle plate 1 has a nozzle 6 for ejecting ink. The vibration plate 3 is provided in parallel with the nozzle plate 1. A piezo element (piezoelectric actuator) 4 for driving the diaphragm 3 is attached to one surface of the diaphragm 3. This piezo element 4
On the upper and lower surfaces, a pair of electrodes 5 for applying a voltage to the piezo element 4 is provided.

[0007] A wall member 8 for forming the pressure chamber 2 is provided between the nozzle plate 1 and the vibration plate 3. Wall member 8
Is made of a hard material. A supply port 7 for supplying ink to the pressure chamber 2 is provided in a part of the wall member 8.

The operation of this configuration will be described. FIG. 43 (B)
As shown in (2), a voltage is applied to the electrode 5 so that the piezo element 4 contracts. Thereby, the piezo element 4
Shrink. However, the side of the piezo element 4 connected to the diaphragm 3 cannot contract. Therefore, there is a difference in the amount of contraction between the upper surface and the lower surface of the piezo element 4.

As a result, the piezo element 4 and the diaphragm 3 bend toward the pressure chamber 2. Due to this bending, pressure is applied to the pressure chamber 2. For this reason, the ink in the pressure chamber 2 is pushed out and ejects from the nozzle 6 as ink particles 9. This method expands and contracts the piezo element 4 in parallel with the diaphragm 3,
So-called a d ₃₁ mode. Similarly, there is a so-called d ₃₃ mode in which the piezo element 4 is vertically extended and contracted to the diaphragm 3.

FIG. 44 (A) shows another conventional example (filed on Jul. 9, 1991, Japanese Patent Application No. 511,885, International Patent Application No. PCT JP 91/0091).
6, International Patent Publication No. WO 92/00849).

As shown in FIG. 44A, a wall member provided between the nozzle plate 1 having the nozzle 6 and the vibration plate 3 is formed by laminating a hard member 8 and an elastic member 11. I have. As a driving means, a wire dot head 12 is provided to face the diaphragm 3.

This operation will be described. As shown in FIG. 44 (B), the diaphragm 3 is pushed by the wire drive by the wire dot head 12. Thereby, the diaphragm 3 compresses the elastic member 11 and applies pressure to the pressure chamber 2. Thus, the ink is ejected from the pressure chamber 2.

[0013]

However, the prior art has the following problems.

In the first prior art shown in FIG. 43A, the periphery of the diaphragm 3 is fixed to the wall of the pressure chamber 2. For this reason, when the diaphragm 3 is curved, a large stress is generated at a connection portion of the diaphragm 3 with the wall of the pressure chamber 2. Since the diaphragm 3 vibrates at several kHz, the stress may cause a fatigue failure, and the connection may be broken.

In the first prior art shown in FIG. 43A, the force generated by the piezo element is the sum of the force for pushing out the ink and the force for bending the diaphragm 3. However, since the periphery of the diaphragm 3 is fixed to the wall of the pressure chamber 2,
A large force is required to bend diaphragm 3. As a result, the force for pushing out the ink is reduced. For this reason, the conversion efficiency of the force generated by the piezo element to the force for pushing out the ink is poor.

In the first prior art shown in FIG. 43A, when the force generated by the piezo element is fixed, the diaphragm 3
In order to maximize the curvature of the diaphragm 3, it is necessary to push the center of the diaphragm 3 with the piezo element. That is, if the central portion of the diaphragm 3 is not pressed, the curvature of the diaphragm 3 becomes asymmetric with respect to the center, and the force for pushing out ink decreases. Diaphragm 3
Is about 1 mm x 1 mm. To push the center, the head assembly accuracy must be several tens of μm.
It is necessary to keep it below. For this reason, assembly is difficult.

In the second prior art shown in FIG. 44A, as shown in FIG.
Even if 2 stops, residual vibration remains on diaphragm 3. If the amplitude of this residual vibration is greater than a certain threshold, ink particles will be formed again. As a result, satellite particles 10 are emitted from the nozzles. Since the head is ejecting ink particles while moving,
When satellite particles are present, dots are printed in the moving direction of the head by the number of satellite particles. For this reason, the print quality is deteriorated such as the character width is widened and the character is blurred.

In the second prior art shown in FIG. 44 (A), the diaphragm 3 and the pressing mechanism of the wire dot head 12 are separated and have a clearance in order to separate the ink head and the driving part. Therefore, the diaphragm 3 is driven in the direction opposite to the nozzle direction to suck ink into the pressure chamber 2 and then driven in the nozzle direction to eject ink, which is an efficient driving method, that is, a so-called negative polarity driving method. Can not.

Accordingly, it is an object of the present invention to provide an ink jet head for increasing the conversion efficiency from the force generated by a piezo element to the force for pushing out ink.

Another object of the present invention is to provide an ink jet head for improving the durability of the head.

Still another object of the present invention is to provide an ink jet head for facilitating head assembly.

Still another object of the present invention is to provide an ink jet head for preventing generation of satellite particles.

Still another object of the present invention is to provide an ink jet head for enabling a negative drive.

[0024]

Means for Solving the Problems FIGS. 1A and 1
(B) is a principle diagram of the present invention.

According to the present invention, there is provided an ink jet head for applying pressure to a pressure chamber 26 for containing ink to eject the ink in the pressure chamber 26, and a nozzle plate 20 having a nozzle 21 for ejecting ink; A pressure plate 22 provided in parallel with the nozzle plate 20; a wall member 24 having elasticity and connecting the nozzle plate 20 and the pressure plate 22 to form the pressure chamber 26; And the pressure plate 2 so as to deform the wall member 24.
2 for driving the piezoelectric actuator 2.

[0026]

According to the present invention, the wall member 24 of the pressure chamber 26 is made of an elastic material. Then, the wall member 24 is deformed via the pressing plate 22 by the piezoelectric actuator 23 fixed to the pressing plate 22. This changes the volume in the pressure chamber 26 to push out the ink.

That is, instead of the vibration plate, a pressure plate 22 that is hardly curved is used. Then, the pressure plate 22 is driven by the piezoelectric actuator 23 to deform the wall member 24 and change the volume in the pressure chamber 26. In this case, since no diaphragm is used, fatigue failure due to vibration can be prevented. At the same time, generation of satellite particles can be prevented.

Further, since the pressure plate 22 is pushed out without bending the vibration plate, the ink ejection energy can be increased. In addition, since the piezoelectric actuator 23 is fixed to the pressing plate 22, negative driving can be performed, and thereby ink can be ejected efficiently.

[0029]

【Example】

(A) Description of Inkjet Head FIG. 2 is a sectional view of a first embodiment of the inkjet head of the present invention.

As shown in FIG. 2, a nozzle for ejecting ink is provided.
The pressure plate 22 is parallel to the nozzle plate 20 having the chisel 21.
Is provided. The pressure plate 22 is made of a thin metal plate.
ing. The thickness of the pressure plate 22 depends on the piezoelectric actuator.
23 has a thickness that does not bend when the pressing plate 22 is pressed.
You. For example, with a thickness of about 20 μm, a Young's modulus of 2.2 × 10
¹¹Pa (Pa is Pascal, Pa = N / m^Two ) Nickel
Etc. are used.

An elastic member 24 constituting a wall member is provided between the nozzle plate 20 and the pressure plate 22. The wall member 24 is provided around the pressure chamber 26,
To form The elastic member 24 has a Young's modulus
Rubber or resin of about 1 × 10 ⁵ Pa to 1 × 10 ⁹ Pa is preferable. In this example, the Young's modulus is 9.6 × 10 ⁵ P
The silicone rubber of a is used. Also, this elastic member 2
The height of 4 is about 60 μm.

A piezo element (piezoelectric actuator) 23 is fixed to the pressing plate 22 with an adhesive.
Electrodes 25 are provided above and below the piezo element 23. Piezoelectric element 23 is of a d ₃₃ mode. Therefore, when the voltage is applied to the electrode 25, the electrode 25 expands and contracts in the vertical direction in the figure.

The wall member 24 is formed of the wall member 2 of the adjacent pressure chamber.
4, a slit 28 is provided. This prevents interference between the pressure chambers.

In this embodiment, when a voltage is applied to the piezo element 23, the pressure plate 22 compresses the wall member 24 by the force generated by the piezo element 23. As a result, the pressure plate 22 moves in parallel and pushes out the ink in the pressure chamber 26.

In this embodiment, an example of driving in the _d33 mode is shown. However, with the electrode 25 on the left and right sides of the piezoelectric element 23, the same effect can be obtained in the d ₃₁ mode expanding and contracting the piezoelectric element 23 in the vertical direction in FIG.

Further, by forming the piezoelectric actuator in a structure in which a plurality of units sandwiching a piezoelectric body between a pair of electrodes are stacked, displacement and generated force can be increased.

According to this structure, since the bending operation of the diaphragm is not used, fatigue failure can be prevented. At the same time, the energy required for bending can be omitted, so that the energy generated by the piezo element 23 can be directly used as the ink ejection energy. Further, since the diaphragm is not bent, the positioning accuracy does not need to be high. Further, the pressing plate 2
Since the piezo element 23 is in close contact with 2, there is no residual vibration and generation of satellite particles can be prevented.

FIG. 3 is a sectional view of a first modified example of the ink jet head of the present invention, FIGS. 4 (A) to 4 (E) are explanatory diagrams of the positive drive operation, and FIGS. 5 (A) to 5 (F). () Is an explanatory diagram of the negative drive operation.

In FIG. 3, the same components as those described in FIG. 2 are described with the same symbols. In the embodiment of FIG. 2, the entire wall member 24 is made of an elastic material. In this modification, the wall member 24 has a laminated structure of a highly rigid wall 24-1 and an elastic member 24-2. Rigid wall 24
-1 is preferably a metal or a resin having a Young's modulus of 1 × 10 ¹⁰ Pa or more. The height of the rigid wall 24-1 is 5
0 μm, and the height of the elastic member 24-2 was 10 μm.

In this example, a silicone rubber having a Young's modulus of 9.6 × 10 ⁵ Pa is used as the elastic member 24-2.

The rigid wall 24-1 and the elastic member 24-2
Is formed as follows. The liquid one-component silicone rubber or the two-component silicone rubber is formed by a printing method such as screen printing or the like to obtain a rigid wall 2.
After forming on 4-1 and aligning the pressing plate 22,
It is cured at room temperature or high temperature (about 120 ° C.) to form a plate-like member.

In this example, the rigid wall 24-1 is used.
In addition, an ink supply port 27 for supplying ink into the pressure chamber 26 is provided. Further, a piezo element 23 is fixed to the pressing plate 22 with an adhesive 30. Electrodes 25 are provided above and below the piezo element 23.
Piezoelectric element 23 is of a d ₃₃ mode. Therefore,
The application of a voltage to the electrode 25 causes expansion and contraction in the vertical direction in the figure.

In this example, of the wall member 24, only the height necessary for deformation is constituted by the elastic member 24-2.
This prevents the wall member 24 from bending. For this reason,
It is possible to further increase the conversion efficiency of the energy of the piezo element 23 to the energy of ink ejection.

The positive drive method will be described with reference to FIGS. This driving method uses the piezo element 23 as shown in FIG.
A positive polarity pulse as shown in FIG.
2 is pushed in one direction in the nozzle direction to eject ink.

FIG. 4B shows an initial state where no voltage is applied. When a voltage is applied to the piezo element 23 at time t = t ₂ , the pressing plate 22 compresses the elastic member 24-2 by the force generated by the piezo element 23. FIG.
As shown in (C), as a result, the meniscus as the ink surface portion is displaced by the
Protrude outside of The pressure around the protruding ink drops sharply because of the air around the protruding ink.

When the applied voltage is further increased, the pressure plate 22 further moves in parallel, and the pressure in the pressure chamber 26 increases. At this time, as shown in FIG. 4D, the amount of ink from the nozzle 21 increases.

As shown in FIG. 4E, the piezo element 23
Stops, the displacement of the pressure plate 22 also stops suddenly. Although the flow of ink in the pressure chamber 26 also stops, the ink that has flowed out of the nozzle advances due to inertia, and eventually separates into ink particles.

Next, the negative driving method will be described with reference to FIGS. 5A to 5F. As shown in FIG. 5A, this driving method drives the piezo element 23 by a triangular wave in the negative direction. In this way, the pressure plate 22 is driven once in the direction opposite to the nozzle direction to suck ink into the pressure chamber, and then returned to the nozzle direction to eject ink.

FIG. 5B shows an initial state where no voltage is applied. As shown in FIG. 5C, the piezo element 23
Is applied, the pressure plate 22 is displaced in the direction opposite to the nozzle by the force generated by the piezo element 23. The meniscus is drawn into the nozzle 21 with the displacement of the pressure plate 22.

When the voltage applied to the piezo element 23 is set to zero, the piezo element 23 returns to the original position. At this time,
The pressure plate 22 also returns to the original position. As shown in FIG. 5D, the meniscus also starts to move. Since the meniscus is confined in the pipe-shaped nozzle 21, the pressure rise in the pressure chamber 26 due to the displacement of the pressure plate 22 is:
It reaches the top of the meniscus. Since the above-mentioned pressure is constantly applied to the meniscus and the ink moving in the nozzle 21, the ink is accelerated until reaching the nozzle 21 outlet.

Next, as shown in FIG. 5E, the ink jumps out of the nozzle 21 with the momentum obtained in the nozzle 21. Since the total sum of the momentum of the ink at the moment when it comes out of the nozzle 21 becomes large, the speed of the ink column becomes larger than that of the positive drive.

As shown in FIG. 5F, the piezo element 23
Stops, the displacement of the pressure plate 22 also stops suddenly. The flow of the ink in the pressure chamber 26 also stops. However, the ink that has flowed out of the nozzle advances due to inertia, and eventually separates into ink particles.

The positive drive and the negative drive will be compared. Assuming that the velocity of the ink particles is v _{1 at} the positive polarity and v ₂ is the velocity at the negative polarity, v ₂ > v ₁ .

Next, the volume V1A between the meniscus in the nozzle and the nozzle outlet when the piezo element 23 starts to push ink is defined as V1P, and the displacement volume of the piezo element 23 converted into the nozzle portion is defined as V1P.

The volume V1 of the ink particles is V1 = V1P in positive polarity driving. That is, since the meniscus is not drawn in from the nozzle outlet, V1A = 0. On the other hand, in the case of the negative drive, V1 = V1P-V1A. Therefore, the volume of the ink particles is smaller in the negative polarity driving.

The kinetic energy E of the ink particles is E
= 0.5 · m · v ² . In the negative drive, the mass m is slightly smaller and the speed v is considerably larger than the positive drive, so that the total kinetic energy E
Is a little bigger. That is, the conversion efficiency from the input energy to the piezoelectric actuator 23 to the kinetic energy of the ink particles is better in the negative polarity.

Further, in the case of the negative drive, since the ink is accelerated in the nozzle 21, the flying direction of the ink particles is
More stable than positive drive. Therefore, in the ink jet, the negative drive is more preferable than the positive drive.

In this regard, in the present invention, the negative polarity drive is possible. Of course, this does not hinder the application of the positive drive. Also in this embodiment, is shown the driving example of d ₃₃ mode, the same effect can be obtained in the d ₃₁ mode.

FIG. 6 is a sectional view of a second modification of the ink jet head of the present invention.

In FIG. 6, the same components as those described in FIG. 3 are indicated by the same symbols. In this variation,
A pressure plate 22 is provided for each pressure chamber 26. This prevents the pressure plates 22 from interfering with each other. Of course, the piezo elements 23 are provided individually corresponding to the pressing plates 22.

FIG. 7 is a sectional view of a third modification of the ink jet head of the present invention.

In FIG. 7, the same components as those described in FIG. 3 are indicated by the same symbols. In this variation,
A pressure plate 22 is provided for each pressure chamber 26. This prevents the pressure plates 22 from interfering with each other. Also, piezo elements 23 are provided individually corresponding to the pressure plates 22. Further, a slit 29 is provided in the elastic member 24-2. Thereby, the elastic member 24-2 is divided into two elastic members.

For this reason, the pressure chamber adjacent to the elastic member can be separated, and mutual interference of the elastic members can be prevented. Moreover, the highly rigid wall 24-2 can be shared with an adjacent pressure chamber.

In these embodiments, the elastic member 24-
2 can also be formed by an adhesive having elasticity.

FIG. 8 is a sectional view of a fourth modification of the ink jet head of the present invention.

In FIG. 8, the same components as those shown in FIG. 3 are denoted by the same symbols.

As shown in FIG. 8, the wall member 24 includes a highly rigid wall 24-1 and a bellows 31. The bellows 31 is made of metal. In this embodiment, a bellows 31 is used as the elastic member 24-2 in FIG. This embodiment also has the same operation and effect as those shown in FIG.

FIGS. 9A and 9B are diagrams showing the configuration of a fifth modified example of the ink jet head of the present invention. FIG.
9A is a cross-sectional view, and FIG. 9B is a top view.

In FIGS. 9A and 9B, FIG.
Those that are the same as those shown by are indicated by the same symbols. In this modified example, a pair of piezo elements 23 are arranged outside the side surface of an elastic member 24 constituting a wall member. One end of the piezo element 23 is connected to the pressure plate 22, and the other end is connected to the nozzle plate 20.

The operation of this configuration will be described. Piezo element 2
3 is contracted, the pressure plate 22 is drawn toward the nozzle plate 20, and the pressure in the pressure chamber 26 is increased. Thereby, ink is ejected.

With this configuration, the same effect as that shown in FIG. 2 can be obtained. Further, the thickness of the head can be reduced.

FIGS. 10A and 10B are views showing the construction of a sixth modified example of the ink jet head of the present invention. FIG. 10A is a sectional view thereof, and FIG. 10B is a top view thereof.

Referring to FIGS. 10A and 10B,
The same components as those shown in FIG. 2 are denoted by the same symbols. In this modification, both elastic members 2 constituting a wall member
4, a piezo element 23 is arranged inside. One end of the piezo element 23 is connected to the pressure plate 22, and the other end is connected to the nozzle plate 20.

The operation of this configuration will be described. Piezo element 2
3 is contracted, the pressure plate 22 is drawn toward the nozzle plate 20, and the pressure in the pressure chamber 26 is increased. Thereby, ink is ejected.

With this configuration, the same effect as that shown in FIG. 2 can be obtained. At the same time, the thickness of the head can be reduced.

FIGS. 11A and 11B are views showing the construction of a seventh embodiment of the ink jet head according to the present invention. FIG. 11A is a sectional view thereof, and FIG. 11B is a top view thereof.

In FIG. 11A and FIG. 11B,
The same components as those shown in FIG. 2 are denoted by the same symbols. In this modification, an elastic member 24 constituting a wall member
Are provided with a pair of piezo elements 23 on the side surface of the piezo element. The piezoelectric element 23 is used in d ₁₅ mode (lateral displacement mode). One side of the piezo element 23 is connected to the pressure plate 22, and the other side is connected to the nozzle plate 20 via the mounting member 32.

When a voltage is applied to the piezo element 23, a lateral displacement occurs in the direction of the arrow in FIG.
Displace in the 0 direction. Thereby, the pressure in the pressure chamber 26 is increased, and the ink is ejected.

With this configuration, the same effect as that shown in FIG. 2 can be obtained, and the thickness of the head can be reduced.

FIGS. 12A and 12B are views showing the construction of an eighth modification of the ink jet head of the present invention. FIG. 12A is a cross-sectional view thereof, and FIG. 12B is a top view thereof.

In FIGS. 12A and 12B,
The same components as those shown in FIG. 2 are denoted by the same symbols. In this modification, the piezoelectric element 23 is used in d ₁₅ mode (lateral displacement mode). The two piezo elements 23 are attached and fixed to a head support member (not shown) via attachment members 33 provided on left and right side surfaces.

When a voltage is applied to the piezo element 23, lateral displacement occurs in the direction of the arrow in FIG. Thereby, the piezo element 2
The bonded portion 3 is displaced upward to displace the pressure plate 22 toward the nozzle plate 20. Thereby, the pressure in the pressure chamber 26 is increased, and the ink is ejected. Even in this configuration, FIG.
The same effects as those shown by are obtained.

FIGS. 13A and 13B are diagrams showing a ninth modification of the ink jet head of the present invention.
Is a cross-sectional view thereof, and FIG. 13B is a perspective view thereof. FIG.
4 (A), (B) and (C) are explanatory diagrams of the operation.

13A and 13B, the same components as those shown in FIG. 2 are denoted by the same symbols. In this modification, the ink supply port 27 is provided in the wall member 24 formed of an elastic member in the configuration of FIG.

The operation will be described with reference to FIGS. 14 (A), (B) and (C). In general, when the pressure plate 22 is displaced and starts pushing the ink, a part of the ink passes through the supply port 27,
It flows backward to the ink supply tank (not shown). Since the amount of backflow causes energy loss, it is desirable that the amount of backflow be as small as possible.

As shown in FIGS. 14B and 14C, when the ink is pushed out by the pressure plate 22, the wall member 2 is pressed.
4 is contracted, so that the cross section of the supply port 27 of the wall member 24 also becomes narrow. When the cross section becomes narrow, the flow path resistance increases,
The ink is less likely to flow back.

On the other hand, when the ink is sucked into the pressure chamber 26, since the wall member 24 extends, the cross section of the supply port 27 is widened and the flow path resistance is reduced. Thereby, the ink flows into the pressure chamber 26 in a short time.

As described above, by providing the supply port 27 in the wall member 24, the supply port 27 itself can have a valve function. For this reason, the energy loss can be reduced, and the ink ejection energy can be increased. In addition, the dimension of the cross section of the supply port 27 when it becomes narrow is
It is preferable to set the displacement amount to several times or less the displacement amount of the pressing plate 22 (about 1 μm).

FIGS. 15A and 15B are sectional views of a tenth modified example of the ink jet head of the present invention.
(A) is a front sectional view thereof, and FIG. 15 (B) is a transverse sectional view thereof.

In FIGS. 15A and 15B, the same components as those shown in FIG. 3 are denoted by the same symbols. In this modification, the ink supply port 27 is provided in the elastic member 24-2 in the configuration of FIG.

Also in this modification, when the ink is pushed out by the pressing plate 22, the elastic member 24-2 is contracted. Thereby, the cross section of the supply port 27 of the wall 24-2 also becomes narrow. When the cross section is narrow, the flow resistance is increased, so that it is difficult for the ink to flow backward.

On the other hand, when the ink is sucked into the pressure chamber 26, the cross section of the supply port 27 is expanded because the elastic member 24-2 is extended. This reduces the flow path resistance, so that the ink flows into the pressure chamber 26 in a short time.

As described above, by providing the supply port 27 in the elastic member 24-2, the supply port 27 itself can have a valve function. Therefore, the energy loss can be reduced, and the energy of ink ejection can be increased.

FIGS. 16A and 16B are sectional views of an ink jet head according to an eleventh modification of the present invention.
FIG. 16A is a front sectional view thereof, and FIG. 16B is a transverse sectional view thereof.

In FIGS. 16A and 16B,
The same components as those shown in FIG. 7 are denoted by the same symbols. In this modification, the ink supply port 27 is provided in the elastic member 24-2 in the configuration of FIG.

Also in this modification, when the ink is pushed out by the pressure plate 22, the elastic member 24-2 is contracted. For this reason, the cross section of the supply port 27 of the elastic member 24-2 also becomes narrow. When the cross section becomes narrow, the flow path resistance increases,
The ink is less likely to flow back.

On the other hand, when the ink is sucked into the pressure chamber 26, the cross section of the supply port 27 is expanded because the elastic member 24-2 is extended. As a result, the flow path resistance decreases, and the ink flows into the pressure chamber 26 in a short time.

As described above, by providing the supply port 27 in the elastic member 24-2, the supply port 27 itself can have a valve function. Therefore, the energy loss can be reduced, and the energy of ink ejection can be increased.

In the above modification, the elastic member 24-
2 can be formed by an elastic adhesive.

In addition to the above-described embodiment, the present invention employs FIG.
In the modifications shown in FIGS. 16A and 16B, the positive driving method and the negative driving method described with reference to FIGS. Also, the configurations of the modifications described with reference to FIGS. 8 to 12 can be applied to the modifications described with reference to FIGS. 13A to 16A. (B) Description of the multi-nozzle head FIG. 17 is an exploded view of the multi-nozzle head of the present invention, and FIG.
Is a sectional view thereof, and FIG. 19 is an exploded sectional view thereof.

As shown in FIG. 17, the multi-nozzle head includes a nozzle plate 40, a flow path plate 41, an elastic plate 42, a pressure plate 43, a holder 44,
A piezoelectric actuator 45.

As shown in FIGS. 18 and 19, the nozzle plate 40 has a large number of nozzles 40-1. In the example of the figure, four rows of 16 nozzles are formed in one row. The flow path plate 41 constitutes the above-described highly rigid member 24-1. The flow path plate 41 forms each pressure chamber 46 and a common ink chamber 48. The elastic plate 42 is the above-described elastic member 24-2. The pressure plates 43 form the individual pressure plates 22. The holder 44 holds the piezoelectric actuator 45 and simultaneously holds the nozzle plate 4.
0, the flow path plate 41, the elastic plate 42, and the pressure plate 43 are fixed.

As shown in FIG. 18, the flow path plate 4
1 is provided with an ink supply port 47 connecting the pressure chamber 46 and the common ink chamber 48. Therefore, this multi-nozzle head is obtained by forming the head of the embodiment of FIGS. 3 and 6 into a multi-nozzle.

Next, a method for forming each plate constituting the multi-nozzle head will be described. First, the elastic plate 42 will be described.

FIG. 20 is an explanatory diagram of a screen printing method for producing an elastic plate, and FIG. 21 is an explanatory diagram of an offset printing method for producing an elastic plate.

A problem in forming the elastic plate is that the elastic plate is formed to have a uniform thickness. Further, even in mass production, it is required to form a uniform thickness. In the present invention, the elastic plate is formed by using a liquid elastic material.

As shown in FIG. 20, the nozzle plate 40
The flow path plate 41 is bonded on the upper side. This channel plate 4
A mesh 81 for screen printing is provided on the surface on the side of the pressure plate 1. Then, the elastic material 82 is traced by the blade (squeegee) 80 via the mesh 81. Thus, uniform application of the elastic material 82 is performed.

The elastic material 82 is applied around the pressure chamber. After that, the pressure plate 43 is positioned on the application surface, placed on the application surface, and pressed. Further, it cures and bonds at room temperature or high temperature (about 120 ° C.). Thereby, the elastic plate 42 is formed.

The elastic material 82 is preferably a rubber or a resin having a Young's modulus after curing of about 1 × 10 ⁵ Pa to 1 × 10 ⁹ Pa. In this embodiment, the Young's modulus is 9.6.
× 10 ⁵ Pa silicone rubber is used. The viscosity at the time of application was 200 cp. The thickness of the elastic layer is 1
The mesh was selected to be 0 μm.

Thus, the elastic layer 82 can be formed by screen printing.

FIG. 21 shows an example in which an elastic layer is formed by offset printing. As shown in FIG. 21, the hopper 23 is filled with a liquid elastic material. Rollers 84-1 to 84-3 having high affinity (wetting) with this elastic material
A liquid layer of an elastic material having a constant thickness is formed on the application roller 84-4 via the liquid crystal display. Thereafter, the flow path plate 41 placed on the nozzle plate 40 is moved in the direction of the arrow. Thereby, a liquid elastic layer is formed on the flow path plate 41. After that, the pressure plate 43 is positioned on the application surface, placed on the application surface, and pressed. Further, it cures and bonds at room temperature or high temperature (about 120 ° C.). Thus, the elastic layer 82 can be formed by the offset printing method.

As described above, by applying the liquid elastic material onto the flow path plate 41, an elastic layer can be formed on the flow path plate 41. Therefore, an elastic layer having a uniform thickness can be easily formed. In addition, since printing is used, it is suitable for mass production.

Further, a method for making the thickness more uniform will be described. The above-described method is a method in which the elastic material is cured by placing the pressing plate 43 on the elastic material in a liquid state. If the elastic material remains liquid, it is difficult to control the thickness of the elastic layer. Then, after applying a liquid elastic material on the flow path plate 41, it is once cured. As a result, even when the pressure plate 43 is pressed, the elastic material does not flow out, and then the adhesive is applied on the elastic material. Then, the resin is cured while pressing the pressure plate 43.

As a result, the pressure plate 43 and the flow path plate 41 adhere to each other, and after the pressure plate 43 is released from the pressure, the elastic layer returns to its original cured thickness. Therefore, an elastic layer having a uniform thickness can be formed. As the adhesive, an elastic material used for the elastic layer can be used.

As described above, by providing the step of once curing the elastic layer, the thickness of the elastic layer can be made more uniform.

FIG. 22 is an explanatory view of another method of making the thickness uniform according to the present invention.

As shown in FIG. 22, the liquid elastic material 42
Next, particles 42-1 having a maximum particle size equal to the desired film thickness are mixed. That is, the particles 42-1 that have been filtered in advance are prepared so that the maximum particle diameter is equal to the desired film thickness.
The particles 42-1 are mixed with the liquid elastic material 42 and sufficiently dispersed. The particles 42-1 are used as spacers. As a result, even when pressure is applied, the thickness of the elastic layer does not fall below the maximum particle size. As a result, a thin and uniform elastic layer can be formed.

For example, when the maximum particle size of SiO is 10 μm,
_{The two} particles are mixed 30 percent with the one-part silicone rubber. This is screen-printed on the channel plate 41. Thereafter, a pressure plate 43 made of a resin film was attached, and then heated at 120 ° C. to be cured. Thus, the thickness of the elastic layer 42 can be set to 10 μm. The particles 42-1 include SiO ₂ , TiO ₂
Or an organic material such as polystyrene or polycarbonate. Further, the content of the particles is suitably 5 wt% to 60 wt%.

According to this method, the thickness of the elastic layer 42 is 10 μm.
m, which is suitable for negative polarity driving.

Next, the flow path plate will be described.

FIG. 23 is an explanatory view of the pressure distribution in the pressure chamber, and FIG.
FIG. 3 is an explanatory view of a flow path plate of the present invention.

As shown in FIG. 23, a pressure Q is generated in the pressure chamber by the pressure generated by the piezoelectric actuator 45. The pressure Q causes the flow path plate 41 to bend. Due to this bending, the volume of the ink to fly from the nozzle is lost. For this reason, it is difficult to efficiently form ink particles.

The material of the flow path plate that minimizes this deflection will be described. As shown in FIG. 24, the thickness of the flow path plate 41 is “h”, the width thereof is “b”, the height of the pressure chamber is “l”, the generated pressure in the pressure chamber is “Q”, The elastic modulus of the road plate 41 is “E”, and the ink ejection volume is “V”. The coefficient of the loss due to the deflection of the flow path plate 41 with respect to the ink ejection volume is set to “k”.

Here, the loss volume due to the bending of the flow path plate 41 is represented by kV. This loss volume is defined by the following equation.

[0125] In ^{kV ≧ 6 · Qbl 5/5} · Eh 3 this equation, the thickness h of the flow channel plate 41, the width b, a height l, the elastic modulus E, satisfies k = 0.01 or less and the relationship Select as follows. In this case, the loss volume becomes 1
It can be reduced to a percentage or less.

For example, consider an ink jet printer capable of printing at 360 dpi. As parameters of the pressure chamber of this printer, generated pressure Q = 15 atm, b = 1
mm, l = 100 μm, h = 92 μm. When a photosensitive resin or the like is used as the flow path plate 41,
Even with the resin having the highest elastic modulus, the elastic modulus E is 4 giga-P
a. This results in a loss of 5.78 pl. Therefore, assuming that the volume of ink particles required to form one dot on the paper surface is 100 pl, a change in the pressure chamber volume of 105.78 pl is required. That is, the efficiency is low.

With respect to the shape of the pressure chamber, the flow path plate 4
In order to reduce the volume loss due to the deflection of 1 to 1% or less with respect to 100 pl, a member having an elastic modulus of 23 giga Pa or more is required.

As a material having such an elastic modulus,
Photosensitive glass, metal materials such as stainless steel, ceramics, and the like are conceivable. The respective elastic modulus E and loss volume kV are calculated. Since the photosensitive glass has E = 70 giga Pa, kV = 0.33 pl. For stainless steel, E =
Since it is 200 giga Pa, kV = 0.0036 pl. Even if ceramics have the lowest elastic modulus, since E = 10,000 giga Pa, kV = 0.
0000272 pl.

Therefore, by using these materials, it is possible to efficiently form ink particles with a small loss volume.

This metal member can be processed by a mechanical processing method such as an electroforming method, an etching method or a press. Glass can be processed with UV-sensitive glass. In the case of ceramics, it can be processed by firing it before machining it by machining or the like. By applying such a processing method, highly accurate patterning can be performed.

FIG. 25 is an explanatory view of another flow path plate of the present invention.

When the height h of the channel plate 41 is high, it is preferable to divide the channel plate 41 into a plurality of plates 410 and stack them. That is, when the plate is patterned by the above-described processing method, the thinner the plate, the higher the patterning accuracy.

In this example, the channel plate 41 is divided into three layers of plates 410. Then, these plates 410 are joined. Here, after the plates 410 are stacked, the plates 410 are covered with the plating layers 411, thereby realizing multilayer bonding.

Further, before the plating is joined, it is preferable to temporarily join the plates 410 by spot welding, bonding, or the like. This can prevent the displacement in the plating process.

In this manner, by forming a flow path plate having a loss volume of 1% or less, it is possible to efficiently form ink particles.

Next, the pressure plate will be described.

FIGS. 26 (A) and 26 (B) are explanatory views of the pressure plate of the present invention, and FIGS. 27 (A) and 27 (B).
FIG. 4 is an explanatory diagram of each of the pressing plates.

In a print head having a large number of nozzles, pressure chambers and pressure plates are required by the number of nozzles. It is desirable to divide the pressure plate into individual nozzles, since each pressure chamber can be independently pressurized. However, the method of joining separate and independent pressure plates for each pressure chamber involves manufacturing difficulties. Therefore, this embodiment provides a pressure plate that is easy to manufacture and can press the pressure chambers individually and independently.

FIG. 26 (B) is a top view of the pressure plate 43, and FIG. 26 (A) is a sectional view taken along line XX ′.
As shown in FIGS. 27A and 27B, each pressing plate 22 has a common holding member 43 at the center of its short side.
0 is connected to a thin rib 431.

As shown in FIG. 27 (A), each pressing plate 22 is pressed by a piezoelectric actuator at a portion indicated by a broken line in the drawing. In this case, as shown in FIG.
The rib 431 is deformed, and pressure can be applied to the ink in the pressure chamber 46.

As described above, since the pressing plates 22 corresponding to the individual nozzles are held by the common holding member 430 via at least two ribs 431 that are thinner than the pressing plate 22,
The parts are integrated. Thereby, the joining operation of the pressure plate 43 becomes easy.

Due to the deformation of the rib 431, the rib 431
Stress is concentrated on Therefore, the stress is designed to be lower than the breaking strength of the rib. Further, since the direction in which the rib 431 is pulled is the long side direction of the pressure plate 22,
It hardly affects the displacement of the pressure plate 22 on the pressure chambers arranged in the short side direction.

In the pressure plate 22, the rib 431 and the common holding member 430 are preferably made of the same member. A hard resin film having a Young's modulus of several giga Pa or more is used.
The pressure plate 43 having the structure shown in FIG. 26B can be obtained by patterning the resin film by die cutting, laser processing, or the like. As the resin film, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or the like can be used.

For example, a PEN film having a thickness of 0.1 mm is used. The size of the pressure chamber is 1.1 mm × 0.19 mm, and the area where the piezoelectric actuator presses the pressure plate 22 (FIG. 2)
7 (B) is 1 mm × 0.1 m
m. Further, the size of the pressure plate 22 is set to 1.2 mm ×
0.26 mm, the thickness of the elastic layer 42 is 10 μm,
Stress calculation was performed by the finite element method, with the Young's modulus of the elastic layer being 1.5 × 10 ⁶ Pa.

According to this calculation, the width of the rib 431 is
Assuming that the length is 0.04 mm and the length is 0.02 mm, the stress is 3 × 10 ⁷ Pa. Therefore, since the breaking strength of the rib material is 2 × 10 ⁸ Pa, it can sufficiently withstand stress.

As shown in FIGS. 26A and 26B, the pressure plate 43 can also serve as a wall of the common ink chamber 48. Thus, the common ink chamber 48 may be manufactured in an open state, similarly to the pressure chamber 46. That is, the common ink chamber 48 is also sealed together by the adhesion of the pressure plate 43. Therefore, the common ink chamber 48 can be formed simultaneously with the adhesion of the pressure plate 22.

FIG. 28 is an explanatory diagram of another pressure plate according to the present invention.

As shown in FIG. 28, the thickness of the rib 431 is smaller than that of the pressing plate 22 and the common holder 430. When the ink in the pressure chamber 46 is pressurized and a predetermined volume of ink is ejected from the nozzle, it is necessary that the pressure plate 22 be hard and not easily deformed. That is, in order to fly a predetermined amount of ink with the minimum displacement, it is necessary to increase the displacement efficiency of the piezoelectric actuator to be pressed.

For this purpose, it is necessary that the pressure plate 22 be hard and not easily deformed. Thereby, the elastic layer between the pressure plate 22 and the pressure chamber is mainly deformed. Pressing plate 2
When 2 is hardened, the integrally formed rib 431 is also hardened. For this reason, the rib 431 is not easily deformed.

Thus, the thickness of the rib 431 is reduced to reduce the cross-sectional area. Thereby, the rib 431 is easily deformed, and the hard pressure plate 22 is obtained.

When a d31 displacement mode piezoelectric actuator is used, it is desirable that such a pressure plate 22 be an insulator. The piezoelectric actuator in the d31 displacement mode is provided on the side of the piezoelectric actuator shown in FIG.
An electrode is provided. Since the tip of the piezoelectric actuator is bonded to the pressing plate 22, when the pressing plate 22 is made of metal, there is a danger of a short circuit. For this reason, the pressing plate 22
Is desirably an insulator. For example, a resin film is preferable as a material for the pressure plate 22 because it is a good insulator.

As a method for preventing the electric short circuit, a method in which an electrode is not formed near the tip of the piezoelectric actuator may be considered. However, in order to ensure a predetermined active length in the piezoelectric actuator, the length of the piezoelectric actuator is correspondingly increased, which is disadvantageous in manufacturing.

It is more convenient for the production that the pressure plate 22 is transparent. When the pressure chamber and the pressure plate 22 are bonded with an elastic adhesive, the thickness of the cured elastic layer is set to a predetermined value (10 μm
２０20 μm). Care must be taken in applying pressure during this bonding. Over-pressing leads to extruding of the adhesive, while under-pressing results in incomplete bonding. For this reason, when examining the bonding conditions, if the pressure plate 22 is transparent, the bonding state can be grasped.

FIGS. 29A and 29B are explanatory views of another pressure plate according to the present invention. As shown in FIGS. 29A and 29B, a thin film portion 432 is provided in a portion forming a wall of a common holding member 430 that forms the common ink chamber 48. This thin film portion 432 forms a pressure damper.

When the pressure plate 22 pressurizes the ink in the pressure chamber 46, the ink flies from the nozzle. At the same time, ink is ejected from the ink supply port 47 to the common ink chamber 48. At this time, the pressure in the common ink chamber 48 increases, causing pressure fluctuations in the other pressure chambers 46. This causes crosstalk.

In order to prevent this pressure fluctuation, it is necessary to provide a pressure damper in the common ink chamber 48. In this embodiment, a part of the common holder 430 is laser-processed or etched to form a pressure damper including the thin film portion 432.

This pressure damper is designed as follows.

The volume displacement V when a uniformly distributed load p is applied to a pressure damper having a Young's modulus E, a length 1, a width w, and a thickness t.
Is represented by the following equation.

V = 0.151 plw ⁵ / Et ³ Accordingly, the acoustic capacity Cd of the pressure damper is expressed by the following equation.

Cd = ΔV / Δp = 0.151 · lw ⁵ / Et ³ On the other hand, the order of the acoustic capacity Cn of the nozzle is 1/10 ¹⁶
１／1/10 ¹⁸ . Therefore, in order to reduce the pressure fluctuation at the time of simultaneous injection of 10 to 30 nozzles to 1% or less,
The order of the acoustic capacity Cd of the pressure damper is 1/10 ¹³
It is necessary to set to 〜10 ¹⁵ .

Therefore, the Young's modulus E, length 1, width w, and thickness t of the pressure damper are determined so that the order of the acoustic capacity Cd of the pressure damper is 1/10 ¹³ to 1/10 ¹⁵ .

FIG. 30 is a structural view of another pressure damper of the present invention.

As shown in FIG. 30, a hole is provided in a part of the wall of the pressure plate 43 forming the common ink chamber.
A thin film 610 was glued with one-component silicone rubber 611 so as to cover this hole. Thereby, a pressure damper is formed.

The film 610 is made of PET.
You. The Young's modulus of PET is 4 × 10 ⁹Pa and thickness
6 μm, surface size is 3.764 × 0.46 mm^TwoIn
Was. In this head, crosstalk was investigated.
As a result, both speed fluctuation and injection rate fluctuation were ± 10%
Less than

As the film 610, in addition to PET, a polymer material such as PI (polyimide), Ni, A
1, metal materials such as SUS can be used.

FIG. 31 is a structural view of still another pressure damper of the present invention.

A hole is formed in a part of the wall of the pressure plate 43 forming the common ink chamber 48. So as to cover this hole,
A thin film 610 was provided. As this film 610, a 10 μm-thick PET coated with a hot-melt adhesive (ethylene-vinyl acetate copolymer) at 2 μm was used. This film 610 is heated at 150 ° C., 5 kg /
A pressure damper was formed by heat fusion under the conditions of cm ² and 5 sec.

FIG. 32 is a configuration diagram of another pressure damper of the present invention.

The pressure damper plate 61 provided on the pressure plate 43 together with the pressure plate 22 is provided on the wall of the common ink chamber 48.
3 is provided. The pressure plate 43 has a thickness of 5 μm.
An m-type PI film provided with a pressure plate 22 made of SUS corresponding to the pressure chamber was used. In this embodiment, since the portion of the pressure plate 43 forming the common ink chamber is a film, the pressure damper can be formed without processing the pressure plate 43.

Next, the piezoelectric actuator 45 will be described.

FIG. 33 is a perspective view of the piezoelectric actuator of the present invention, FIG. 34 is a plan view of a lead frame for the piezoelectric actuator of FIG. 33, FIG. 35 is a perspective view of the lead frame of FIG. 34, and FIG. FIG. 37 is an explanatory view of an electrode structure of the piezoelectric actuator.

The piezoelectric actuator needs to be formed corresponding to each nozzle. Generally, such a piezoelectric actuator has been formed by laminating a plurality of piezoelectric bodies. However, the method of laminating the piezoelectric bodies in multiple layers has a problem that the manufacturing cost is high. Therefore, it is desirable to form a piezoelectric actuator having a shape corresponding to each nozzle with a single-layer piezoelectric body.

On the other hand, in the ink jet head having the above-described elastic layer, the amount of displacement of the piezoelectric actuator is small. Therefore, a single-layer piezoelectric body can be used.
As shown in FIG. 33, a large number of piezoelectric elements 451 corresponding to each nozzle are formed in a single-layer piezoelectric block 45.

This piezoelectric element 451 is formed as follows. First, the arrow A is drawn with a dicing saw.
A number of cuts are made in the piezoelectric block 45 from the direction to form each piezoelectric element 451. As a result, the entire piezoelectric element 451 has a comb shape in one row. Next, a cut is made in the center of the piezoelectric block 45 from the direction of arrow B to form a groove 450. Thus, two rows of piezoelectric element 451 groups are formed.

By cutting the piezoelectric block 45 in this manner, the piezoelectric elements 451 of two rows of nozzles can be formed. Since each piezoelectric element 451 has a single-layer structure, the piezoelectric actuator 45 can be manufactured at a lower price than a laminated piezoelectric element. Further, since the piezoelectric body itself has a comb shape, the strength is high and high integration is possible.

The piezoelectric actuator having such a structure is as follows.
The structure for taking out the electrodes becomes easy. That is, as shown in FIG. 37, electrodes 451-1 and 451-2 are formed on both surfaces of the piezoelectric element 451 by plating. Thus, the side of each piezoelectric element 452, the electrode is formed, it is possible to drive the d ₃₁ mode.

This electrode is taken out as shown in FIGS.
The lead frame 50 is used as shown in FIG. That is, as shown in FIG. 34, a common electrode 500 is provided at the center, and a plurality of individual electrodes 501 and 502 extending from the center are provided. As shown in FIG. 34, after cutting at the cut position CUT-1 to form an independent lead frame, as shown in FIG. 35, the lead frame 50 is bent in accordance with the width of the piezoelectric block 45.

Next, the cut position CUT-2 shown in FIG.
Cut with Thereby, in the lead frame 45, the tip of the common electrode 500 and the tip of the individual electrode 501 are separated. Thereafter, as shown in FIG. 36, the common electrode 500 of the lead frame 50 is fitted into the central groove 450 of the piezoelectric block 45, and the lead frame 50 is
Lower to the lower end of 50 and temporarily fix.

At this time, as shown in FIG.
00, the tip of each individual electrode 501 contacts the second electrode 451-2 of each piezoelectric element 451 such that the tip of the individual electrode 501 contacts the first electrode 451-1 of each piezoelectric element 451. Position. The common electrode 500 and the tip of the individual electrode 501 are coated with solder in advance.

In this state, the piezoelectric block 45 is brought under the near-infrared lamp. Then, the focus of the lamp is set on the contact portion of the electrode,
Irradiates near infrared lamp light. At this time, it is desirable that the near-infrared lamp is of a focus type so as not to affect the piezoelectric element. Further, if the irradiation is performed for a long time, the piezoelectric element is deteriorated. Therefore, the irradiation time is desirably 1 second to 60 seconds.

By irradiating the light of the near-infrared lamp in this manner, the solder of the lead frame 50 previously coated is melted. Accordingly, the tip of the common electrode 500 is connected to the first electrode 451 of each piezoelectric element 451.
In FIG. 1, the tip of each individual electrode 501 is adhered to the second electrode 451-2 of each piezoelectric element 451.

Thereafter, the lead frame 5 shown in FIG.
0 is cut at the cut position CUT-3. With this configuration, the leads can be drawn out using both side surfaces of the piezoelectric body block 45, so that the piezoelectric actuator 45
Can be reduced in size. Further, since the bonding is performed by a non-contact near-infrared lamp, the bonding can be performed more easily than a method using a soldering iron.

FIG. 38 is a lateral view of the multi-nozzle head of the present invention, and FIG. 39 is a side view of the multi-nozzle head of the present invention.

As shown in FIG. 38, the piezoelectric actuator 45 formed as described above is held by the holder 44. Each piezoelectric element 451 of the piezoelectric actuator 45 is bonded to the pressing plate 22 of the pressing plate 43. Further, as shown in FIG. 39, two piezoelectric actuators 45 are arranged in parallel for four nozzle rows.

FIG. 40 is an explanatory view of another lead frame of the present invention, FIG. 41 is an explanatory view of a connection state of another lead frame of the present invention, and FIG. 42 is a view showing an electrode structure thereof.

As shown in FIG. 40, a common electrode 512,
A lead frame 50 to which the individual electrodes 513 are connected is prepared. The lead frame 50 is cut at the cut position CUT. Then, the common electrode 512 and the individual electrode 51
3 is fitted into the piezoelectric block 45 described above. At this time, as shown in FIG. 42, the tip of each individual electrode 513 is connected to each piezoelectric element 451 so that the tip of the common electrode 512 contacts the first electrode 451-1 of each piezoelectric element 451. Is positioned so as to be in contact with the second electrode 451-2. The common electrode 500 and the tip of the individual electrode 501 are coated with solder in advance.

Further, as shown in FIG.
The 12 and the individual electrode 513 are taken out on the same surface of the piezoelectric block 45. Then, the common electrode 512 and the individual electrode 51
3 and top and bottom. An insulator such as plastic is interposed between the two electrodes to insulate the two electrodes.

At this time, each of the lead frames 512, 51
3 is solder-coated, and temporarily fixed at a position where the piezoelectric block 45 is to be bonded. Then, light from a near-infrared lamp is applied to bond. Furthermore, the lead frame 51 of the common electrode
2 and the lead 514 are connected by a connection line 515. In this way, the leads can be pulled out using the side surfaces of the piezoelectric block 45. (C) Description of Other Embodiments In addition to the above-described embodiments, the following modifications are possible in the present invention.

The method for forming the elastic layer described with reference to FIGS. 20 to 22 can be applied to a head in which the wall member described with reference to FIG.

Similarly, the pressure plate described in FIG. 26 and subsequent figures can be applied to a head in which the wall member described in FIG. 2 is made of only an elastic layer.

As described above, the present invention has been described with reference to the embodiments.
Various modifications are possible within the scope of the present invention, and these are not excluded from the scope of the present invention.

[0192]

As described above, according to the present invention,
The following effects are obtained.

[0193] Instead of the vibration plate, the pressure plate 22, which is hard to bend, is driven by the piezoelectric actuator 23 to deform the wall member 24, so that fatigue destruction due to vibration can be prevented and generation of satellite particles can be prevented.

Further, since the pressure plate 22 is pushed out without bending the vibration plate, the ink ejection energy can be increased.

In addition, the piezoelectric actuator is
2, it is possible to perform negative polarity driving, thereby enabling efficient ink ejection.

[Brief description of the drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a sectional view of the first embodiment of the present invention.

FIG. 3 is a sectional view of a first modified example of the present invention.

FIG. 4 is an explanatory diagram of a positive drive operation in the configuration of FIG. 4;

FIG. 5 is an explanatory diagram of a negative drive operation in the configuration of FIG. 4;

FIG. 6 is a sectional view of a second modified example of the present invention.

FIG. 7 is a sectional view of a third modified example of the present invention.

FIG. 8 is a sectional view of a fourth modified example of the present invention.

FIG. 9 is a configuration diagram of a fifth modified example of the present invention.

FIG. 10 is a configuration diagram of a sixth modified example of the present invention.

FIG. 11 is a configuration diagram of a seventh modified example of the present invention.

FIG. 12 is a configuration diagram of an eighth modified example of the present invention.

FIG. 13 is a configuration diagram of a ninth modified example of the present invention.

FIG. 14 is an operation explanatory view of a ninth modified example of the present invention.

FIG. 15 is a sectional view of a tenth modified example of the present invention.

FIG. 16 is a sectional view of an eleventh modified example of the present invention.

FIG. 17 is an exploded view of the multi-nozzle head of the present invention.

FIG. 18 is a cross-sectional view of the multi-nozzle head of FIG.

19 is an exploded cross-sectional view of the multi-nozzle head of FIG.

FIG. 20 is an explanatory diagram of a screen printing method for forming an elastic layer according to the present invention.

FIG. 21 is an explanatory diagram of an offset printing method for forming an elastic layer according to the present invention.

FIG. 22 is an explanatory view of another method of making the thickness uniform according to the present invention.

FIG. 23 is an explanatory diagram of a pressure distribution of the pressure chamber of the present invention.

FIG. 24 is an explanatory view of a flow path plate of the present invention.

FIG. 25 is an explanatory view of another flow path plate of the present invention.

FIG. 26 is an explanatory view of a pressure plate of the present invention.

FIG. 27 is an explanatory view of a pressure plate having the configuration of FIG. 26;

FIG. 28 is an explanatory view of another pressure plate of the present invention.

FIG. 29 is an explanatory view of another pressure plate of the present invention.

FIG. 30 is a configuration diagram of another pressure damper of the present invention.

FIG. 31 is a configuration diagram of still another pressure damper of the present invention.

FIG. 32 is a configuration diagram of another pressure damper of the present invention.

FIG. 33 is a perspective view of the piezoelectric actuator of the present invention.

34 is a plan view of a lead frame used for the piezoelectric actuator of FIG.

FIG. 35 is a perspective view of the lead frame of FIG. 34.

FIG. 36 is an assembly configuration diagram of the piezoelectric actuator of FIG. 33.

FIG. 37 is an explanatory diagram of the electrode structure of FIG. 36.

FIG. 38 is a lateral view of the multi-nozzle head of the present invention.

FIG. 39 is a side view of the multi-nozzle head of the present invention.

FIG. 40 is an explanatory diagram of another lead frame of the present invention.

41 is an explanatory diagram of a connection state of the lead frame of FIG. 40.

FIG. 42 is an explanatory view showing the electrode structure of FIG. 41.

FIG. 43 is an explanatory diagram of the first related art.

FIG. 44 is an explanatory diagram of a second conventional technique.

[Explanation of symbols]

 Reference Signs List 20 nozzle plate 21 nozzle 22 pressurizing plate 23 piezoelectric actuator 24 wall member 24-1 member having high rigidity 24-2 elastic layer 27 ink supply port

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Michinori Kuchiami 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Akira Nakazawa 1015 Ueodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited ( 72) Inventor Fumio Yamagishi 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Junji Kashioka 1015 Kamikodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Sakai Shino Kanagawa Prefecture Fujitsu Limited (72) Inventor Osamu Taniguchi 1015 Kamidadanaka, Nakahara-ku, Kawasaki, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Hiromitsu Soneda 1015 Uedanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Fujitsu Limited (72) Inventor Tomohisa Mikami 10 Kamikadanaka, Nakahara-ku, Kawasaki-shi, Kanagawa 15 Fujitsu Limited (72) Inventor Shigeharu Suzuki 1015 Kamiodanaka Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited

Claims (14)

(57) [Claims] 1. An ink jet head for applying pressure to a pressure chamber containing ink to eject the ink in the pressure chamber, comprising: a nozzle plate having a nozzle for ejecting ink; and a nozzle plate provided in parallel with the nozzle plate. A pressure member having elasticity and connecting the nozzle plate and the pressure plate to form the pressure chamber; and a pressure member fixed to the pressure plate and deforming the wall member. An ink jet head having a piezoelectric actuator for driving a pressure plate. 2. The ink jet head according to claim 1, wherein said wall member is formed of an elastic member. 3. The ink jet head according to claim 1, wherein the wall member has a structure in which a member having high rigidity and an elastic member having low rigidity are laminated. 4. The ink jet head according to claim 3, wherein a supply port for supplying ink to the pressure chamber is provided in the highly rigid member. 5. The ink jet head according to claim 3, wherein a supply port for supplying ink to the pressure chamber is provided in the elastic member. 6. The ink jet head according to claim 2, wherein a slit for preventing interference between adjacent pressure chambers is provided in the elastic member. 7. The ink jet head according to claim 1, wherein the piezoelectric actuator is driven to have a negative polarity. 8. The ink jet head according to claim 2, wherein the elastic member has a Young's modulus of 1 × 10 ⁵ Pa to 1 × 10 ^5.
An inkjet head comprising a member having a range of ⁹ Pa. 9. The ink jet head according to claim 2, wherein the elastic member is formed by printing a liquid elastic material on the nozzle plate and then curing the liquid elastic material. 10. The ink-jet head according to claim 3, wherein the elastic member is formed by printing a liquid elastic material on one surface of the high-rigidity member and then hardening the liquid. 11. The ink jet head according to claim 2, wherein the elastic member is made of a low-rigidity adhesive. 12. The ink-jet head according to claim 2, wherein said elastic member is formed of a bellows. 13. The ink jet head according to claim 1, wherein said piezoelectric actuator is provided between said nozzle plate and said pressure plate. 14. The ink-jet head according to claim 1, further comprising: a common holding member for holding said pressing plate; and a rib connecting said pressing plate to said common holding member. .