JPH0557887A - Ink jet head - Google Patents

Abstract

PURPOSE:To provide a drop on-demand type ink jet printer capable of easily removing air bubbles invading from nozzles and easily and certainly filling a head with ink. CONSTITUTION:An ink jet head 11 is constituted by laminating a first substrate 12 equipped with piezoelectric elements 14 to a second substrate 13. Pressure chambers 15 and an ink supply passage 16 supplying ink to the pressure chambers 15 are formed to the surface of the first substrate 12 and the piezoelectric elements 14 are arranged corresponding to the positions of the pressure chambers 5 to generate pressure at a part of the rear of the first substrate 12. The nozzles 17 communicating with the pressure chambers 15 are formed to the second substrate 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet head for a drop-on-demand inkjet printer.

In this type of ink jet head, the presence of air inside the head adversely affects printing, and therefore the solution of this problem is an important issue.

[0003]

2. Description of the Related Art As shown in FIG. 4, a conventional ink jet head 1 includes a nozzle row 3 in which a plurality of nozzles 2 are arranged in the direction of gravity (vertical direction in the figure), and a piezoelectric element (pressure generating means) 4. A pressure chamber 5 and a common ink chamber 6 are provided. A plurality of pressure chambers 5 are formed in communication with each nozzle 2, and piezoelectric elements 4 are provided corresponding to each pressure chamber 5. The common ink chamber 6 communicates with each pressure chamber 5 and receives ink supply from an ink cassette (not shown) via a tube 7.

Therefore, the ink from the ink cassette is
Piezoelectric element 4 which is divided into respective nozzles 2 via common ink chamber 6 and pressure chamber 5 and is provided integrally with pressure chamber 5.
Is driven to be ejected in the form of particles from the nozzle 2.

[0005]

However, in the above-described conventional structure, the ink passage is complicated and long, and the ink passage can stagnate, so that air easily remains in the head and it is difficult to remove the air.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet head which can easily remove bubbles that have penetrated from a nozzle and can easily and reliably fill the head with ink.

[0007]

In order to achieve the above object, according to the present invention, there is provided a first substrate having a pressure chamber and an ink supply path for supplying ink to the pressure chamber, and the pressure chamber. A nozzle which is connected to the first substrate and a second substrate which is attached to the first substrate, and a pressure which is provided corresponding to the position of the pressure chamber and which generates a pressure on a part of the back surface of the first substrate. The configuration (first configuration) is characterized by being configured with a generation unit.

In the ink jet head of the first structure, the nozzle is provided at the center of the pressure chamber or at the position farthest from the ink supply path (second structure).

Further, in the ink jet head having the first structure, the second substrate is attached to the first substrate via an anaerobic adhesive (third structure).

[0010]

The ink supplied from the ink supply path fills the pressure chamber and is discharged from the nozzle. In this case, the air in the pressure chamber is discharged from the nozzle, but as the ink is filled, the air moves and continues to be discharged from the nozzle to complete the ink filling. In addition, when air enters from the nozzle etc., the wall surface of the ink passage is wet with ink, so the adhesion force of the air to the wall surface is weak, and by directing the ink from the pressure chamber to the nozzle, it will be put on this flow. Air can be easily discharged.

When the nozzle is provided at the position farthest from the ink supply path, the air is discharged most smoothly. Further, when an anaerobic adhesive is used for bonding the first and second substrates, the adhesive remaining in the nozzle or the like does not cure because it comes into contact with air, and the solvent can be easily flowed into the ink passage. To be removed.

[0012]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 shows a first embodiment.

FIG. 1 is a structural explanatory view of an ink jet head 11 of this example. FIG. 1 (A) is a side sectional view of the ink jet head, FIG. 1 (B) is a front view of a first substrate 12, and FIG.
(C) is a front view of the second substrate 13. The structure and operation of the inkjet head 1 are as follows.

The ink jet head 11 comprises a first substrate 12 and a second substrate 13 made of glass, metal or the like, and a piezoelectric element (pressure generating means) 14. First substrate 12
A pressure chamber 15 and an ink supply path 16 for supplying ink to the pressure chamber 15 are formed by etching on the surface of the. A nozzle 17 communicating with the pressure chamber 15 is formed in the second substrate 13, and the second substrate 13 is the first substrate 12
Are stuck together. The pressure chamber 15 is supplied with ink from an ink cartridge (not shown) through an ink supply passage 16 and a common ink chamber 18 that communicate with the nozzle 17 at the center and communicate with the lower portion.

The piezoelectric element 14 is for generating a pressure in a part of the pressure chamber 15, and is mounted on the outer wall 15a of the pressure chamber 15. The piezoelectric element 14 has a rectangular plate shape of about 1 × 2 mm, and the pressure chamber 15 also has a shape conforming to this.

The ink sucked from the ink cartridge by the suction mechanism (not shown) from the nozzle 17 at the time of filling the ink fills the ink supply passage 16 and the pressure chamber 15 and is discharged from the nozzle 17. in this case,
Since the ink supply path 16 is formed on one substrate 12 by etching and has a flow path shape without stagnation, the air moves without remaining in the flow path and is completely discharged from the nozzle 17. It

As a result, the printing operation is started when the air inside the pressure chamber 15 is completely removed and the pressure chamber 15 is filled with ink. Then, even if air is sucked in from the nozzle 17 thereafter, the wall surface of the ink passage is wet with ink and the adhesive force of the air to the wall surface is weak, and the air is discharged from the nozzle 17 along with the flow of ink.

As described above, in the structure of this example, since the flow path has no stagnation, the ink can be easily and reliably filled in the head, and the bubbles that have entered the head can be easily removed.

A second embodiment is shown in FIGS. 2 and 3.

2A and 2B are structural explanatory views of the ink jet head 21 of this embodiment. FIG. 2A is a side sectional view of the ink jet head, FIG. 2B is a front view of the first substrate 12, and FIG.
(C) is a front view of the second substrate 22. The structure and operation of the inkjet head 1 are as follows. In addition,
The same reference numerals are used for the same members as in the previous example.

The ink jet head 21 is constructed by laminating the second substrate 22 on the first substrate 12 similar to the previous example. The second substrate 22 has a nozzle 23 and is attached to the first substrate 12. The nozzle 23 communicates with a position farthest from the ink supply path 16 of the pressure chamber 15. Therefore, the air is discharged most smoothly when the ink is filled.

When the substrates are formed by etching glass, the first and second substrates 12 and 22 are usually laminated by fusing the glasses together at a high temperature. in this case,
Since the fusion is performed at a high temperature, thermal deformation (for example, a dent is formed on the flat surface or the dimension is changed due to heat shrinkage). Therefore, by applying an anaerobic adhesive to the substrate on which the nozzle is formed on the spinner, a uniform and thin adhesive can be formed, and the bonding without thermal deformation can be performed. The process will be described below with reference to FIG.

Photosensitive glass is used for the first substrate 12 and the second substrate 22, and the flow path (ink supply path 16 and pressure chamber 15) and the nozzle 23 are formed by etching. Next, as shown in FIG. 3 (A), the anaerobic adhesive (L
1-504, Loctite Co., Ltd. 24 to the second substrate 2
By applying to No. 2, or in this case, using a spinner, it is possible to apply evenly and thinly. After that, as shown in FIG. 3B, the two substrates 12 and 22 can be bonded by pressing them. The adhesive remaining in the nozzle 23 does not cure because it is in contact with air, and can be removed as shown in FIG. 3C by flowing the solvent in the flow path. This bonding method can also be applied to the case of the previous example.

[0025]

As described above, according to the present invention, it is possible to easily and reliably fill the ink jet head with the ink, and it is also possible to easily remove the air bubbles that have entered from the nozzle. .. In this case, it is more effective to provide the nozzle at the position farthest from the ink supply path.

Further, when a method of adhering the first and second substrates using an anaerobic adhesive is adopted, thermal deformation can be eliminated, and an ink jet head having high dimensional accuracy and small characteristic variation can be obtained. it can.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of an inkjet head according to a first embodiment of the present invention, FIG. 1 (A) is a side view of the inkjet head, FIG. 1 (B) is a front view of a first substrate, and FIG. C)
[Fig. 4] is a front view of a second substrate.

2A and 2B are structural explanatory views of an inkjet head according to a second embodiment of the present invention, FIG. 2A is a side sectional view of the inkjet head, FIG. 2B is a front view of a first substrate, and FIG.
(C) is a front view of the second substrate.

FIG. 3 is a process diagram for adhering a substrate with an anaerobic adhesive according to a second embodiment of the present invention. FIG. 3 (A) shows a state where the adhesive is applied to the second substrate, and FIG. FIG. 3C shows a state in which both substrates are pressed together, and FIG. 3C shows a state in which the adhesive in the nozzle is removed.

FIG. 4 is a perspective view of a conventional inkjet head.

[Explanation of symbols]

 11, 21 Inkjet head 12 First substrate 13, 22 Second substrate 14 Piezoelectric element (pressure generating means) 15 Pressure chamber 16 Ink supply path 17,23 Nozzle 24 Anaerobic adhesive

Claims (3)

[Claims] 1. A first substrate (12) on a surface of which a pressure chamber (15) and an ink supply path (16) for supplying ink to the pressure chamber (15) are formed, and the pressure chamber (15). ), A nozzle (17) communicating with the second substrate (13) attached to the surface of the first substrate (12) and the pressure chamber (15) are provided at positions corresponding to the second substrate (13). An inkjet head comprising a pressure generating means (14) for generating a pressure on a part of the back surface of the first substrate (12). 2. The ink jet head according to claim 1, wherein the nozzle (17) is provided at the center of the pressure chamber (15) or at a position farthest from the ink supply passage (16). 3. The second substrate (13) is connected to the first substrate (1).
The ink jet head according to claim 1, wherein the ink is adhered to 2) via an anaerobic adhesive (24).