JPH09234871A - Structure for adhesion to nozzle plate and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high quality printed result by a method wherein an adhesive is prevented from being swollen out into an ink passage of a nozzle in adhesion of a nozzle plate to an actuator. SOLUTION: An opening shape of a tapered part 4b of a nozzle 4a on a joint surface of an actuator to a nozzle plate 4 together with both vertical and horizontal sizes is so formed as to be less than the opening shape of a channel 3, and a difference in level 4c is formed to the nozzle plate 4. Thereby, though an adhesive between the actuator and the nozzle plate 4 is swollen out from the joint surface by pushing in adhesion of both components, the adhesive stays at the difference in level 4c, and does not enter an ink passage of the nozzle 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding structure for a nozzle plate constituting an ink jet head or the like and a bonding method therefor. In particular, the adhesive used when bonding the nozzle plate to the actuator and the cover plate is The present invention relates to a bonding structure for a nozzle plate that does not protrude into an ink flow path of a nozzle and a bonding method therefor.

[0002]

2. Description of the Related Art Regarding the conventional adhesion of a nozzle plate to an actuator and a cover plate, FIG.
This will be described with reference to FIG. 5A and 5B are cross-sectional views showing a state in which the nozzle plate is adhered to the cover plate and the actuator, FIG. 5A is a cross-sectional view of a surface including a channel, and FIG. FIG. 6 is a cross-sectional view taken along the line A ′. Conventionally, the nozzle plate 4 and the actuator 2
The opening shape of the nozzle 4a and the opening shape of the channel 3 of the actuator 2 on the joint surface of the and were formed in the same size. That is, the vertical dimension L2 of the channel 3 and the vertical dimension l2 of the shape of the joint surface of the tapered portion 4b with the actuator 2 are equal to each other, and the horizontal dimension W2 of the channel 3 is the same.
And the lateral dimension w2 of the tapered portion 4b on the joint surface with the actuator 2 are set to be equal to each other. And
An epoxy resin or the like is interposed as an adhesive between the nozzle plate 4 and the actuator 2 and the cover plate 8 set in this way, and is sandwiched and pressed by a jig such as a pressing member and a base member and heated in that state. Then, these members are adhered by curing an epoxy resin or the like.

[0003]

However, the conventional method of bonding the nozzle plate 4 to the actuator 2 and the cover plate 8 as described above has the following problems. Generally, the nozzle plate is manufactured from a resin that is easy to mold and has a smooth surface, while the actuator and cover plate are manufactured by cutting a material such as a piezoelectric element by machining. , There are fine irregularities on the surface, and it does not finish as smoothly as a nozzle plate. Therefore, in order to bond the surfaces of these members to each other, it is necessary to fill the gap formed by the unevenness with an adhesive. However, it is difficult to accurately set the amount of adhesive required for this, and when the two members are pressed to actually bond them, the adhesive should cure while protruding into the ink flow path of the nozzle. There is. In this case, the protruding adhesive hinders the smooth flow of the ink and affects the ink ejection speed, so that a good printing result cannot be obtained. The present invention has been made to solve the above-mentioned problems, and when the nozzle plate and the actuator and the cover plate are bonded, a state in which the adhesive protrudes into the ink flow path of the nozzle and is cured. It is an object of the present invention to provide a bonding structure for a nozzle plate and a bonding method that can obtain high-quality printing results by eliminating the above problem.

[0004]

In order to achieve the above object, a nozzle plate bonding structure according to a first aspect of the present invention is provided with an actuator having a plurality of channels formed of side walls of a piezoelectric element, and a recording medium. A nozzle plate in which nozzles are formed at positions corresponding to each channel for ejecting ink, and the opening shape of the nozzle on the joint surface between the nozzle plate and the actuator is Is also formed to be small.

In the above structure, since the opening shape of the nozzle in the joint surface between the nozzle plate and the actuator is smaller than the opening shape of the channel, the adhesive will stick out from the joint surface when the nozzle plate and the actuator are adhered. However, the adhesive does not reach the ink flow path of the nozzle. Therefore, since the smooth flow of the ink is not hindered, the ink ejection speed is not adversely affected, and a high quality printing result can be obtained.

The nozzle plate adhering structure according to a second aspect of the present invention is the nozzle plate adhering structure according to the first aspect, in which the nozzle opening shape is arranged in the ink jet side direction of the nozzle plate. It is formed in a tapered shape that becomes thinner as it gets closer.

In the above structure, the nozzle opening is tapered so that it becomes thinner as it approaches the ink jet side of the nozzle plate, so that the change in the pressure in the channel due to the change in the capacity of the channel is highly transmissive. Therefore, the ink can be made to flow more smoothly and the ink can be ejected comfortably.

A nozzle plate adhering structure according to a third aspect of the present invention is the nozzle plate adhering structure according to the first or second aspect, wherein the nozzle plate is made of a polyimide resin. .

In the above structure, the polyimide resin is
Since it is a resin having a high melting point and a high softening point and excellent thermal characteristics, it does not deform and deteriorate due to softening and melting during heating or printing when bonding the nozzle plate and the actuator, and further, Since the resin is easy to mold,
A high quality nozzle plate can be obtained.

Further, the adhesion structure of the nozzle plate according to the invention of claim 4 is the adhesion structure of the nozzle plate according to any one of claims 1 to 3, wherein the nozzle plate is an ink droplet. It is used for an ink jet type print head which jets and prints.

In the above structure, since the adhesive does not stick out into the ink flow path of the nozzle formed in the nozzle plate and harden, the ink flows smoothly and an appropriate ink ejection speed can be obtained. Quality print results can be obtained.

The nozzle plate adhering structure according to a fifth aspect of the present invention is the nozzle plate adhering structure according to any one of the first to fourth aspects, wherein the nozzle plate and the actuator are joined together. The nozzle opening area on the surface is 80% to 95% of the channel opening area.
It is what it was.

In the above structure, the opening area of the nozzle at the joint surface between the nozzle plate and the actuator is
Since it is 80% to 95% of the opening area of the channel,
Even if the adhesive squeezes out from the joint surface when the nozzle plate and the actuator are bonded, the adhesive does not enter the ink flow path of the nozzle, and since the step between the nozzle and the channel is small, ink bubbles form in this step. Is hard to collect. Therefore, the ink can be ejected more comfortably and a high quality printing result can be obtained.

According to a sixth aspect of the present invention, there is provided a nozzle plate adhering method, wherein an actuator having a plurality of channels formed of side walls of a piezoelectric element and each channel for ejecting ink onto a recording medium. A method of adhering a nozzle plate having a nozzle formed at a position corresponding to the above, wherein the nozzle opening shape at the joint surface between the nozzle plate and the actuator is formed to be smaller than the channel opening shape. The nozzle plate is bonded to the actuator.

In the above method, since the opening shape of the nozzle at the joint surface between the nozzle plate and the actuator is smaller than the opening shape of the channel, even if the adhesive sticks out from the joint surface at the time of adhering the nozzle plate and the actuator. , The adhesive does not reach the ink flow path of the nozzle. Therefore, since the smooth flow of the ink is not hindered, the ink ejection speed is not adversely affected, and a high quality printing result can be obtained.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION A nozzle plate bonding structure and method according to an embodiment of the present invention will be described below with reference to the drawings. First, an inkjet head to which the nozzle plate bonding structure and the bonding method of the present invention are applied will be described. The inkjet head described here is applied to an inkjet printer or the like, in which a piezoelectric element is used on the side wall of the pressure chamber, and an ink droplet is ejected using a change in internal pressure of the pressure chamber due to shear deformation by the element. To do.

FIG. 1 (a) is an exploded perspective view of an ink jet head, and FIG. 1 (b) is a view showing how the ink jet head and electrodes are connected. The actuator 2 of the inkjet head 1 is a piezoelectric substrate made of piezoelectric ceramics, which is a piezoelectric element, in which grooves parallel to each other are formed by cutting such as dicing, and a large number of channels 3 to be ink chambers are formed. . A nozzle plate 4 having nozzles 4a (ink ejection ports) is attached to one end of the channel 3. This nozzle plate 4
Is formed of a polyimide resin so as not to be deformed or deteriorated even in the manufacturing process of the inkjet head 1 or at the time of high temperature during printing. A side wall 5 (hereinafter, referred to as a piezoelectric side wall) forming the channel 3 is indicated by an arrow B.
It is formed by a piezoelectric element polarized in the direction, and an electrode 6 for applying an electric field in the direction perpendicular to the polarization direction is formed on the upper half surface of the piezoelectric sidewall 5.

A cover plate 8 having an ink supply port (liquid supply means) 7 is covered on the upper portion of the actuator 2 having the channel 3 formed therein. Channel 3
Through the ink supply port 7 to an ink cartridge (not shown). The ink used for printing is supplied from this ink cartridge through the ink supply port 7 to the ink chamber formed by the channel 3, and is ejected from the nozzle 4a of the nozzle plate 4. With such a configuration, the cross-sectional shape of the channel 3 becomes a rectangle surrounded by the piezoelectric side wall 5 and the cover plate 8.

Further, a printed circuit board 10 on which electrodes 9 are printed is arranged below the actuator 2. The electrode 9 and the electrode 6 on the surface of the piezoelectric side wall 5 are connected by a wire 11, and the electrode 9 is connected to a head driver 15 that drives the inkjet head 1. The head driver 15 is connected to the power source by the connection line 16,
It is connected to the ground by a connection line 17, and a voltage is applied to the electrode 6 by this head driver 15. In addition, the head driver 15 uses the signal line 18 to
C of a recording device provided with the inkjet head 1
It is connected to a PU (not shown) and controlled by this CPU. The head driver 15 is provided in a recording device such as a printer in which the inkjet head 1 is provided.

Next, ejection of ink by the ink jet head 1 will be described with reference to FIG. FIG. 2 (a)
Is a vertical cross-sectional view of the inkjet head 1, and FIG.
FIG. 6 is a diagram showing a state in which a voltage is applied to the piezoelectric sidewall 5 and the piezoelectric sidewall 5 is distorted. An actuator is composed of the electrodes 6 (61, 62) formed on the upper half of the piezoelectric side wall 5. A cover plate 8 is attached to the upper portion of the piezoelectric side wall 5 with an epoxy resin (adhesive) 13. The electrodes 61 and 62 are formed by plating, and the electrodes 6
A + potential is connected to 1 and a GND is connected to the electrode 62, whereby an electric field in the directions of arrows 12a and 12b is generated on the piezoelectric sidewall 5. Then, the volume of the ink chamber (channel 3) changes due to the piezoelectric thickness sliding deformation of the upper half of the piezoelectric side wall 5 to which the electrodes 61 and 62 are attached. As a result, the internal pressure of the channel 3 increases, and the ink in the channel 3 is ejected from the nozzle 4a (FIG. 1A). When the voltage application is stopped, the piezoelectric side wall 5 has no electric field, and the piezoelectric side wall 5 which has been distorted returns to its original state.
CPU of recording device provided with inkjet head 1
Also, the head driver 15 (FIG. 1) controls the above-mentioned operation of the inkjet head 1, that is, voltage application, based on the print data sent from the host computer or the like, thereby performing the print operation on the recording medium. Be seen.

Next, the adhesion of the above-mentioned members constituting the ink jet head 1, the actuator 2, the cover plate 8, the nozzle plate 4 and the like will be described. FIG. 3 is a diagram showing a state in which a plurality of cover plates 8 are placed corresponding to each actuator 2 on a piezoelectric substrate on which a plurality of actuators 2 are formed. When the actuator 2 and the cover boot 8 are adhered to each other, in order to improve productivity, an actuator body 19 in which channels 3 for a plurality of actuators are formed on one piezoelectric substrate and a plurality of cover plates corresponding to the channels 3 are provided. 8 and is glued,
As shown in FIG. 3, the cover plate 8 is placed on the actuator body 19 via an epoxy resin (adhesive).
Next, the cover plate 8 and the actuator body 19 are sandwiched and pressed by a jig (not shown) such as a pressing member and a base member, and heated in this state to cure the epoxy resin, thereby removing the cover plate 8 and the actuator body 19. To glue. Then, the nozzle plate 4 is adhered to the cover plate 8 and the actuator body 19 thus adhered, with the position of the nozzle 4 a corresponding to the position of the channel 3. The nozzle plate 4 is adhered by pressing and heating with an epoxy resin as in the above.

Here, the bonding structure of the nozzle plate 4, the cover plate 8 and the actuator body 19 will be described with reference to FIG. 4A and 4B are cross-sectional views showing a state in which the nozzle plate 4 is bonded to the cover plate 8 and the actuator body 19, where FIG. 4A is a cross-sectional view taken along a plane including the channel 3 and FIG. It is sectional drawing in C'plane. Nozzles 4a formed on the nozzle plate 4
As shown in FIG. 4A, the opening shape is formed in a tapered shape portion 4b that becomes thinner as the nozzle plate 4 approaches the ink ejection side direction. Further, the opening shape of the joint surface of the tapered portion 4b with the actuator 2 is smaller than the opening shape of the channel 3 in both vertical and horizontal dimensions. That is, as shown in FIG. 4B, the vertical dimension l of the shape of the joint surface of the tapered portion 4b with the actuator 2 is larger than the vertical dimension L1 of the channel 3.
1 is smaller than the lateral dimension W1 of the channel 3, and the lateral dimension w of the shape of the joint surface of the tapered portion 4b with the actuator 2 is smaller than the lateral dimension w1.
1 is set to be small. Note that, by setting in this way, the step 4c is formed on the nozzle plate 4.

Due to the presence of the step 4c, the epoxy resin (adhesive) interposed between these members is pressed by the pressure applied when the nozzle plate 4 and the actuator body 19 and the cover plate 8 are bonded together. Even when the epoxy resin extends to the inside of the nozzle 3, the epoxy resin stays in the step 4c and does not enter the ink flow path of the nozzle 4, that is, the tapered portion 4b.

Here, if the step 4c is too large, ink bubbles tend to accumulate in the step 4c, and if the step 4c is too small, the epoxy resin easily enters the tapered portion 4b of the nozzle 4a, which adversely affects the ink ejection. Therefore, the area of the opening shape of the nozzle 4a at the joint surface between the nozzle plate 4 and the actuator 2 is
The opening area is preferably set to 80% to 95%. With this setting, the above problem can be solved.

As described above, according to the bonding structure and the bonding method of the nozzle plate 4 of the present embodiment, the nozzle 4a
Since the shape of the taper-shaped portion 4b at the joint surface with the actuator 2 is smaller than the opening shape of the channel 3 in both vertical and horizontal dimensions, the nozzle plate 4, the actuator body 19 (actuator 2), and the cover plate. When the nozzle plate 4 and the actuator body 19 (actuator 2) and the cover plate 8 are pressed in the step of adhering 8 and 8 with an adhesive such as an epoxy resin, even if the adhesive protrudes into the channel 3, the protrusion The adhesive remains on the step 4c of the nozzle plate 4 and does not enter the ink flow path (tapered portion 4b) of the nozzle 4a. Therefore, the protruding adhesive does not hinder the smooth flow of the ink in the actuator 3 and the nozzle 4a, and does not adversely affect the ejection of the ink. Therefore, the inkjet head 1 to which the adhesive structure and the adhesive method are applied can be used. , High quality printing results can be obtained.

Further, since the nozzle 4a is formed with the tapered portion 4b, the transmissibility of the pressure change due to the change in the capacity of the channel 3 is improved, and it is smoother than in the case where the tapered portion 4b is not formed. Ink can be made to flow, and ink can be ejected more comfortably.

The present invention is not limited to the above embodiment, and various modifications can be made. For example, in the above embodiment, the opening shape of the joint surface of the tapered portion 4b of the nozzle 4a with the actuator 2 is smaller than the opening shape of the channel 3 in both vertical and horizontal dimensions. The opening shape of the shape portion 4b may be formed so that only the vertical dimension or the horizontal dimension is smaller than the opening shape of the channel 3. However, in this case, the other dimension of the opening shape of the tapered portion 4b is the same as the opening shape of the channel 3. Further, in the above-mentioned embodiment, the nozzle plate 4 is made of the polyimide resin, but it is not limited to the polyimide resin as long as it is made of a material having heat resistance and easiness of formation equivalent to the polyimide resin. Not a thing.

[0028]

As described above, according to the nozzle plate bonding structure and the nozzle plate bonding method of the first aspect of the present invention, and the nozzle plate bonding method of the sixth aspect, the nozzle at the joint surface between the nozzle plate and the actuator is formed. Since the opening shape of is smaller than the opening shape of the channel, during the bonding process, when the nozzle plate and the actuator in which the adhesive is interposed are pressed to heat and cure, the adhesive does not protrude into the channel of the actuator. However, the protruding adhesive does not enter the ink flow path of the nozzle. Therefore, the protruding adhesive does not hinder the smooth flow of the ink and does not adversely affect the ink ejection speed, so that a high quality printing result can be obtained.

Further, according to the second aspect of the present invention, the nozzle plate has a taper shape in which the opening of the nozzle is tapered toward the ink ejection side of the nozzle plate. The transmissibility of pressure change due to the capacity change is improved, the ink flows more smoothly, and the ink can be ejected more comfortably.

According to the nozzle plate adhesion structure of the third aspect of the present invention, the polyimide resin is a resin which is easy to mold, has a high melting point and a high softening point, and is excellent in thermal characteristics. Therefore, even when the nozzle plate and the actuator are bonded to each other under heating or under high temperature conditions during printing, there is no deformation and deterioration due to softening and melting. Therefore, a high quality nozzle plate can be obtained.

Further, according to the nozzle plate bonding structure of the fourth aspect of the invention, since the adhesive does not stick out into the ink flow path of the nozzle formed in the nozzle plate and harden, the ink is Since it flows smoothly and an appropriate ink ejection speed is obtained, high quality printing results can be obtained.

According to the adhesion structure of the nozzle plate of the fifth aspect of the invention, the opening area of the nozzle at the joint surface between the nozzle plate and the actuator is 80% to 95% of the opening area of the channel. Therefore, even if the adhesive squeezes out due to the pressure applied when the nozzle plate and the actuator are adhered, they will not enter the ink flow path of the nozzle, and since the step between the nozzle and the channel is small, ink bubbles will not easily accumulate. Become. Therefore, high quality printing results can be obtained.

[Brief description of drawings]

1A is an exploded perspective view of an inkjet head to which a nozzle plate adhesive structure and an adhesive method according to the present invention are applied, and FIG. 1B is a view showing a connection state between the inkjet head and an electrode. .

2A is a vertical cross-sectional view of the inkjet head, and FIG. 2B is a diagram showing a state in which a voltage is applied to an electrode of the inkjet head and a piezoelectric side wall is distorted.

FIG. 3 is a diagram showing a state in which a plurality of cover plates are placed corresponding to each actuator on a piezoelectric substrate on which a plurality of actuators are formed.

4A and 4B are cross-sectional views showing a bonding structure of a nozzle plate, a cover plate, and an actuator body according to the present invention, where FIG. 4A is a cross-sectional view of a surface including a channel, and FIG. It is sectional drawing in the -C 'surface.

5A and 5B are cross-sectional views showing a bonding structure of a nozzle plate, a cover plate and an actuator according to a conventional technique, FIG. 5A is a cross-sectional view of a surface including a channel, and FIG. It is sectional drawing in the AA 'surface shown to a).

[Explanation of symbols]

 1 Inkjet head 2 Actuator 3 Channel 4 Nozzle plate 4a Nozzle 4b Tapered shape 4c Step 5 Piezoelectric side wall 8 Cover plate

Claims (6)

[Claims] 1. A bonding structure of an actuator having a plurality of channels formed of side walls of a piezoelectric element, and a nozzle plate having nozzles formed at positions corresponding to the respective channels for ejecting ink onto a recording medium. 2. The adhesive structure for a nozzle plate, wherein the opening shape of the nozzle on the joint surface between the nozzle plate and the actuator is formed to be smaller than the opening shape of the channel. 2. The adhesive structure for a nozzle plate according to claim 1, wherein the opening shape of the nozzle is formed in a taper shape that becomes thinner as the nozzle plate approaches the ink ejection side direction. 3. The nozzle plate bonding structure according to claim 1, wherein the nozzle plate is made of polyimide resin. 4. The nozzle plate according to claim 1, wherein the nozzle plate is used in an ink jet print head that ejects ink droplets to print. Adhesive structure. 5. The opening area of the nozzle at the joint surface between the nozzle plate and the actuator is 80% to 95% of the opening area of the channel, according to any one of claims 1 to 4. An adhesive structure for a nozzle plate according to claim 1. 6. An actuator having a plurality of channels formed of side walls of a piezoelectric element and a nozzle plate having nozzles formed at positions corresponding to the channels for ejecting ink onto a recording medium are bonded together. In the method of bonding a nozzle plate, the nozzle plate formed so that the opening shape of the nozzle on the joint surface between the nozzle plate and the actuator is smaller than the opening shape of the channel is bonded to the actuator. How to attach nozzle plate.