JP2003025570A - Ink jet recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent adhesive from adhering to or flowing into a nozzle while bonding a nozzle plate and an actuator section with sufficient adhesion strength and reliable sealing performance at the time of manufacturing a piezoelectric ink jet head where the nozzle plate having nozzle holes corresponding to respective pressure chambers of the actuator section is bonded through adhesive to the actuator section arranged in parallel with the pressure chambers having one open end while covering the open end of the pressure chamber. SOLUTION: A continuous adhesive capturing groove 15 is made around a nozzle hole 11 on the rear surface of a nozzle plate 12. Consequently, intrusion of adhesive 13 can be prevented over the entire circumference of the nozzle hole 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric ink jet head which ejects ink from nozzle holes by selectively applying electric signals to a plurality of pressure generating means for recording flying droplets. .

[0002]

2. Description of the Related Art Inkjet printers are widely used for office automation and are used as output means of digital cameras for individuals, and high image quality and high definition are required for the purpose of photographic printing. Head miniaturization and droplet controllability are required.
On the other hand, inkjet printers are attracting attention for FA applications because of their function as micromachines capable of ejecting finely divided ink droplets, and are expected to have a wide range of application fields.

FIG. 4A is a perspective view showing the structure of a conventional piezoelectric ink jet head, and FIG. 4B is a sectional view taken along the line AA of the ink jet head. In this piezoelectric inkjet head, a plurality of channels 1 are formed, and a base 5 made of a piezoelectric element in which electrodes 4 are arranged along a partition wall 2 between the channels 1 to a wire bonding region 3 behind the channels, and an ink supply hole. An actuator portion 9 having each channel as a pressure chamber 8 is formed by adhering a cover 7 made of the same material as that of the base 1 on which the 6 is formed, or glass, ceramics, a resin material, or the like. Then, the actuator portion 9 in which each pressure chamber 8 is opened
A nozzle plate 12 made of a resin material, a glass material, or the like, in which nozzle holes 11 corresponding to the pressure chambers 8 are formed, is fixed to the front end face 10 of the above with an adhesive 13. When the nozzle plate 12 is fixed to the front end surface 10 of the actuator portion 9, sufficient adhesive force that does not cause peeling is required and reliable sealing property is required.

Regarding the adhesive force, it is known that the thinner the adhesive layer is, the higher the adhesive force is. On the other hand, regarding the sealing property, it is ideal to form an adhesive layer that completely blocks the interface between both materials, and it is desired to apply a large amount of adhesive. Therefore, generally, by applying a large amount of adhesive and then applying pressure and heating,
A thin adhesive layer is formed to secure the adhesiveness, and the adhesive that sticks out when the pressure is applied is used to secure the sealing property.

However, in the ink jet head, the bonding area of the front end face 10 of the actuator portion 9 is very fine, and the diameter of the nozzle hole 11 of the nozzle plate 12 is as small as 0.02 mm to 0.06 mm. If the amount of adhesive is large, the adhesive may flow into the nozzle hole 11 to form a protrusion on the inner surface of the nozzle hole 11 having a smooth taper, or to block the nozzle hole 11. As a result, the amount of ejected ink decreases or ink cannot be ejected. Conversely, if the amount of adhesive is too small,
The nozzle plate 12 and the actuator portion 9 cannot be sufficiently sealed.

In order to solve such a problem, the technique disclosed in Japanese Unexamined Patent Publication No. 7-117230 discloses a method shown in FIG.
As shown in FIG.
The excess adhesive is prevented from flowing into the nozzle hole 11 by forming the groove 14 for capturing the excess adhesive in the vicinity of 1 and in the bonded portion of the actuator portion 9 to the front end surface 10. is doing.

[0007]

However, the groove 14 for trapping the above-mentioned adhesive (hereinafter referred to as the adhesive trapping groove 14) is formed in the portion where the front end face 10 of the actuator portion 9 is adhered, that is, the pressure chamber. In a portion facing the partition wall 2 forming 8 and a plurality of portions are formed at intervals from each other, and there is no portion opened to the outside at the time of bonding. Therefore, the adhesive agent that is not captured in the adhesive agent capturing groove 14 may flow out and flow into the nozzle hole 11, or the air may be captured in the adhesive agent capturing groove 14.

In particular, when the thermosetting epoxy adhesive used in the above-mentioned prior art is used, the viscosity is lowered during curing, so that air is easily trapped inside the adhesive trapping groove 14, As a result, the nozzle plate 12 may be distorted, and the inkjet head cannot be manufactured accurately.

Therefore, it is still a problem to fix the nozzle plate 12 and the actuator section 9 with sufficient adhesive force and reliable sealing property.

[0010]

In order to solve the above problems, in the ink jet head of the present invention, an adhesive trap groove is formed on the back surface of the nozzle plate so as to surround the nozzle holes or open the ends. With this, it is possible to trap excess adhesive in the adhesive trapping groove, and it is possible to form a meniscus at the edge portion on the nozzle hole side in the adhesive trapped in the adhesive trapping groove, It is possible to prevent the adhesive from flowing out to the nozzle hole side. On the contrary, it is possible to apply a large amount of adhesive and pressurize, and it is possible to secure both the adhesive force and the sealing property without clogging the nozzle holes.

That is, the present invention according to claim 1 is characterized in that an actuator portion in which pressure chambers having one end opened are formed in parallel,
A piezoelectric ink jet head in which a nozzle plate having nozzle holes corresponding to each pressure chamber is fixed with an adhesive so as to cover the open end of the pressure chamber, and the nozzle hole is formed on the back surface of the nozzle plate. Since the surrounding continuous adhesive trap groove is formed, the adhesive can be prevented from entering the entire circumference of the nozzle hole.

According to a second aspect of the present invention, in the ink jet head according to the first aspect, the adhesive trapping groove is formed so as to face the partition wall separating the pressure chambers and the regions on both sides thereof. It is particularly useful when the diameter of the nozzle hole is large relative to the width of the pressure chamber.

According to a third aspect of the present invention, an actuator portion in which pressure chambers whose one end is open is formed in parallel is provided with a nozzle plate having nozzle holes corresponding to each pressure chamber so as to cover the open end of the pressure chamber. A piezoelectric ink jet head fixed to the nozzle plate with an adhesive, wherein a plurality of adhesive trapping grooves in a direction intersecting the arrangement direction of the nozzle holes are provided on the back surface of the nozzle plate, at least one end of each of which is the nozzle plate. Since it is formed so as to reach the end of the adhesive, and a part of the adhesive trapping groove is opened to the outside, distortion during curing of the adhesive can be suppressed more effectively.

According to a fourth aspect of the present invention, in the ink jet head according to the third aspect, the adhesive trapping groove is formed so as to face the partition wall that separates the pressure chambers from each other. Since the adhesive can be captured, the adhesive can be effectively prevented from flowing out to the nozzle hole side.

According to a fifth aspect of the present invention, in the ink jet head according to the fourth aspect, the adhesive trapping groove is formed narrower than the partition wall that separates the pressure chambers from each other. By making the width narrower than the width, the bonding area between the nozzle plate and the actuator can be secured, so that stable bonding becomes possible.

According to a sixth aspect of the present invention, in the ink jet head according to any of the first to fifth aspects, the adhesive trapping groove is formed deeper than the height of the adhesive to be applied. Since the groove is formed deeper than the adhesive height at the time of attachment, the excess adhesive can be reliably captured.

According to a seventh aspect of the present invention, in the ink jet head according to any one of the first to sixth aspects, the adhesive capturing groove is formed by laser processing, and the groove is formed with high accuracy. Therefore, it is possible to effectively and stably prevent the adhesive from flowing into the nozzle hole. Therefore, the ejection accuracy is increased.

According to the present invention of claim 8, in the ink jet head according to any one of claims 1 to 6, the adhesive agent capturing groove is formed by etching, and accurate molding can be efficiently performed. . Therefore, the productivity of the nozzle plate is increased.

According to a ninth aspect of the present invention, a nozzle plate having nozzle holes corresponding to each pressure chamber is formed in an actuator portion in which pressure chambers having one end opened are arranged in parallel, and the open end of the pressure chamber is closed. When manufacturing a piezoelectric type inkjet head by fixing as described above, after applying an adhesive to the open end surface of the actuator unit, the nozzle plate having an adhesive capturing groove formed on the back surface to capture the excess adhesive is It is placed on the open end surface of the actuator part, pressed, and allowed to stand until the adhesive hardens.By applying a large amount of adhesive, the nozzle hole will not be clogged and the adhesive strength and sealing performance will be improved. Both can be secured.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION A piezoelectric ink jet head according to an embodiment of the present invention will be described below with reference to the drawings. Since each of the following inkjet heads has almost the same configuration as the conventional one described above with reference to FIG. 4, the illustration of the overall configuration is omitted, and a member having the same action as the conventional one is illustrated. The same number as 4 will be used for the description. (Embodiment 1) FIG. 1 (a) is an enlarged front view of a piezoelectric ink jet head according to Embodiment 1 of the present invention, and FIG. 1 (b) is a sectional view taken along line BB of the ink jet head.

As shown in the figure, in the ink jet head, a nozzle hole 11 corresponding to each pressure chamber 8 is formed on a front end face 10 of an actuator portion 9 made of a piezoelectric ceramic in which pressure chambers 8 having one open end are formed in parallel. The adhesive 1 is formed so that the nozzle plate 12 thus formed covers the opening 8a of the pressure chamber 8.
It is fixed at 3.

In manufacturing this ink jet head, the nozzle plate 12 is made of a polyimide film (plate material) having a thickness of 50 μm, and has a rectangular shape on the back surface so as to surround the nozzle hole 11 and a pressure chamber. Adhesive trapping grooves 15 were formed so as to face the openings 8a of No. 8 of FIG. The processing of the adhesive agent capturing groove 15 was performed by an excimer laser.

Then, the front end face 10 of the actuator portion 9
A two-component epoxy adhesive having a viscosity of 3000 cps as the adhesive 13 was impregnated in the porous material and then transferred in an arbitrary amount.

After that, the nozzle plate 12 and the actuator portion 9 are temporarily aligned by aligning the nozzle hole 11 and the opening 8a of the pressure chamber 8 with each other by using a dedicated nozzle attaching jig having a fine position adjusting mechanism. A pressure of 2 MPa was applied while confirming that there was no deviation, and in that state, the adhesive 13 was heated and cured at 100 ° C. for 60 minutes.

The ink jet head manufactured in this manner was washed with a pressure resistance test for confirming the adhered and fixed state of the nozzle plate 12 and the actuator section 9. In this pressure resistance test, the state of the nozzle holes 11 is judged by the state of the organic solvent jetted from the nozzle holes 11 by sending in the organic solvent at a pressure of 1 MPa from the ink supply holes 6 by a dedicated washing machine. When the adhesive enters the inside of the nozzle hole 11 and completely blocks the nozzle hole 11, the organic solvent is not ejected from the nozzle hole 11. When the adhesive partially enters the inside of the nozzle hole 11, the injected organic solvent is deflected as compared with that ejected from another nozzle hole 11. After completion of the pressure resistance test, the state of the nozzle hole 11 and the peeling of the sticking were confirmed by a stereoscopic microscope.

As a result of the pressure resistance test, clogging and deflection of jetting were not observed in all the nozzles 11, and no adhesive penetration into the nozzle holes 11 or peeling of the adhesives was observed in subsequent observation with a stereoscopic microscope. From this, it can be seen that the sealant and the sufficient adhesive force were obtained by the adhesive 13 on the outer peripheral side of the nozzle hole 11 and the portion facing the partition wall 2.

After that, the nozzle plate 12 was peeled off and the back surface thereof was observed. As a result, the adhesive 1 flowed in the direction from the portion facing the periphery of the opening 8a of the pressure chamber 8 toward the nozzle hole 11.
No. 3 is captured by the adhesive capture groove 15, and its nozzle hole 11
It was found that a meniscus was formed at the edge portion near the edge, which prevented the adhesive 13 from entering the nozzle hole 11. (Embodiment 2) FIG. 2 (a) is an enlarged front view of a piezoelectric inkjet head according to Embodiment 2 of the present invention, and FIG. 2 (b) is a sectional view taken along line CC of the inkjet head.

This ink jet head is the first embodiment.
What is different from the above is that the adhesive trap groove 16 is formed in a region up to the nozzle hole 11 in a region facing the partition walls 2 separating the pressure chambers 8 and regions on both sides thereof.

This ink jet head was washed in the same manner as the above and also served as a pressure resistance test.
No clogging or deflection of jetting was observed in all the nozzle holes 11, and no intrusion of adhesive into the nozzle holes 11 or no peeling of adhesive was observed in subsequent observation with a stereoscopic microscope.
It was found that the adhesive 13 such as the outer peripheral side of the nozzle hole 11 and the portion facing the partition wall 2 provided the sealability and sufficient adhesive force. Such an adhesive capturing groove 16 is effective when the diameter of the nozzle hole 11 is larger than the width of the pressure chamber 8. (Embodiment 3) FIG. 3 (a) is an enlarged front view of a piezoelectric ink jet head according to Embodiment 3 of the present invention, and FIG. 3 (b) is a sectional view taken along line D-D of the ink jet head.

This ink jet head is the first embodiment.
The difference is that the adhesive capturing groove 17 is different from the nozzle hole 1
This is a point that at least one end (here, both ends) of each of the plurality of nozzles is arranged in the direction orthogonal to the arrangement direction of 1 so as to reach the end of the nozzle plate 12.

This ink jet head was washed in the same manner as the above and also served as a pressure resistance test.
No clogging or deflection of jetting was observed in all the nozzle holes 11, and no intrusion of adhesive into the nozzle holes 11 or no peeling of adhesive was observed in subsequent observation with a stereoscopic microscope.
It was possible to obtain a good adhesive state, adhesive strength, and sealability. However, the air 18 may be trapped in the adhesive trap groove 17, but since the end portion of the adhesive trap groove 17 is open to the outside, it does not cause the distortion of the nozzle plate 12 unlike the conventional case. It was

At this time, it is preferable that the width of the adhesive capturing groove 17 is (W-10 μm) or less with respect to the width W of the partition wall 5, whereby a sufficient bonding area can be secured.

When forming the adhesive trap grooves 15, 16 and 17 described in each of the first, second and third embodiments, by forming the adhesive trap grooves 15 deeper than the height of the adhesive 13 to be applied, the adhesive is adhered to the outside of the grooves. It is possible to prevent the agent 13 from overflowing. In addition, laser processing such as an excimer laser enables highly accurate groove shape, and etching processing improves productivity.

[0034]

As described above, according to the present invention, the nozzle plate is formed by forming the adhesive trapping groove on the back surface of the nozzle plate so as to surround the nozzle hole or open the end. When adhering to the actuator portion, it is possible to prevent the adhesive layer from entering the nozzle holes without controlling the thickness of the adhesive layer with high precision, and it is possible to realize an accurate inkjet head.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a discharge unit of a piezoelectric inkjet head according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of an ejection unit of a piezoelectric inkjet head according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of an ejection unit of a piezoelectric inkjet head according to a third embodiment of the present invention.

FIG. 4 is a schematic overall configuration diagram of a conventional piezoelectric inkjet head.

5 is a configuration diagram of an ejection unit of the piezoelectric inkjet head of FIG.

[Explanation of symbols]

2 partitions 8 pressure chambers 9 Actuator part 11 Nozzle hole 12 nozzle plate 13 Adhesive 15 Adhesive capture groove 16 Adhesive capture groove 17 Adhesive capture groove

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshinori Amano             1 Juden Matsushita, 1-8 Koshinmachi, Takamatsu City, Kagawa Prefecture             Child Industry Co., Ltd. (72) Inventor profitability insurance             1 Juden Matsushita, 1-8 Koshinmachi, Takamatsu City, Kagawa Prefecture             Child Industry Co., Ltd. F-term (reference) 2C057 AF93 AG44 AP23 AP27 AP31                       BA03 BA14

Claims (9)

[Claims] 1. A nozzle plate having nozzle holes corresponding to the respective pressure chambers is fixed to an actuator portion in which pressure chambers having one open end are formed in parallel with an adhesive so as to cover the open ends of the pressure chambers. A piezoelectric ink jet head, wherein an ink jet head having a continuous adhesive trapping groove surrounding the nozzle hole is formed on the back surface of the nozzle plate. 2. The ink jet head according to claim 1, wherein the adhesive agent capturing groove is formed so as to face the partition wall that separates the pressure chambers and the regions on both sides thereof. 3. A nozzle plate having nozzle holes corresponding to the respective pressure chambers is fixed to an actuator portion in which pressure chambers having one open end are formed in parallel with an adhesive so as to cover the open ends of the pressure chambers. A piezoelectric type inkjet head, wherein a plurality of adhesive trapping grooves in a direction intersecting with the arrangement direction of the nozzle holes are provided on the back surface of the nozzle plate so that at least one end of each reaches the end part of the nozzle plate. The formed inkjet head. 4. The ink jet head according to claim 3, wherein the adhesive agent capturing groove is formed so as to face a partition wall that separates the pressure chambers from each other. 5. The ink jet head according to claim 4, wherein the adhesive trap groove is formed narrower than the partition wall that separates the pressure chambers. 6. The ink jet head according to claim 1, wherein the adhesive agent trap groove is formed deeper than the height of the applied adhesive agent. 7. The ink jet head according to claim 1, wherein the adhesive trap groove is formed by laser processing. 8. The ink jet head according to claim 1, wherein the adhesive agent capturing groove is formed by etching. 9. A piezoelectric type in which a nozzle plate having nozzle holes corresponding to each pressure chamber is fixed to an actuator portion in which pressure chambers having one open end are formed in parallel so as to close the open end of the pressure chamber. When manufacturing the inkjet head of, after applying adhesive to the open end surface of the actuator part, a nozzle plate with an adhesive trap groove on the back surface to catch the excess adhesive is provided on the open end surface of the actuator part. A method for manufacturing an inkjet head, which comprises arranging, pressing, and leaving to stand until the adhesive is cured.