JPH06134983A - Ink-jet head - Google Patents

Abstract

PURPOSE:To provide an ink-jet head, wherein a piezoelectric element can be arranged without position deviation with respect to the position of a pressure chamber, and the sizes and the flying speeds of ink droplets and the like are not dispersed for every nozzle, with respect to the ink-jet head for perfroming the recording by discharging the ink droplets. CONSTITUTION:Ink, which is contained in the inside, is discharged as the ink droplets through a nozzle 7 by applying pressure. For this purpose, a pressure chamber 2, which is formed in a recessed shape, is made to communicate with one surface of a silicon single crystal wafer 1. A recess part 4 is formed in the recessed shape in conformity with the pressure chamber 2. These parts are provided. A vibrating plate 5, which is formed on the wall part of the silicon single crystal wafer for separating the recess part 4 and the pressure chamber 2, is vibrated. For this purpose, a piezoelectric element 9, which is fixed to the recess part 4, is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head for ejecting ink droplets for recording.

The ink jet recording system has features such as a simple structure, easy colorization and no noise, and is expected as the mainstream of future recording systems.

[0003]

2. Description of the Related Art In order to eject ink droplets from an ink jet head, a vibrating plate provided facing the pressure chamber is vibrated to apply an ejection pressure to the ink in the pressure chamber.

Generally, a piezoelectric element vibrates the diaphragm, and the piezoelectric element is provided in close contact with the surface of the diaphragm corresponding to the position of the pressure chamber. Conventionally, such piezoelectric elements have been formed to have a size corresponding to the size of the pressure chamber and then bonded to the surface of the vibration plate one by one.

[0005]

However, since it is necessary to attach the same number of piezoelectric elements to the ink jet head as the number of nozzle holes for ejecting ink droplets, each piezoelectric element is adhered to the vibrating plate one by one. Is very time-consuming and increases the manufacturing cost of the head.

Further, in order to miniaturize the head, it is necessary to arrange the pressure chambers at a high density. Therefore, it is necessary to make the piezoelectric element small in accordance with it, and accordingly it is necessary to reduce the thickness. .

However, if the piezoelectric element is made too small and thin (for example, the size is 1 × 1 mm or less and the thickness is 0.1 mm or less), it becomes very difficult to handle at the time of assembling. The element cannot be made too small.

Further, the smaller and denser the piezoelectric elements are, the more difficult it is to accurately align the piezoelectric elements and the pressure chambers, and as a result, the size of the ink droplet and the flying speed of each nozzle are different. The quality of the print will vary and the print quality will be degraded.

Therefore, the present invention is to provide an ink jet head in which the piezoelectric element can be arranged without displacement with respect to the position of the pressure chamber, and the size and flight speed of ink drops do not vary from nozzle to nozzle. To aim.

[0010]

In order to achieve the above object, the ink jet head of the present invention has nozzle holes for ink contained therein as shown in FIG. 1 for explaining an embodiment. In order to apply a pressure for ejecting as an ink droplet from 7, the pressure chamber 2 formed in a recess on one surface of the silicon single crystal wafer 1 communicating with the ink supply path 3 and the silicon single crystal wafer 1 On the other side,
Recessed portion 4 formed by recessing in alignment with the pressure chamber 2
And a piezoelectric element 9 fixed to the recess 4 in order to vibrate the diaphragm 5 formed by the wall of the silicon single crystal wafer 1 that isolates the recess 4 from the pressure chamber 2. It is characterized by being provided.

The piezoelectric element 9 may be formed by filling the recess 4 with a piezoelectric material 29. Further, the pressure chamber 2 and the recess 4 may be formed by aligning both surfaces of the silicon single crystal wafer 1 by etching.

[0012]

Since the piezoelectric element 9 is fixed to the concave portion 4 formed by aligning with the pressure chamber 2, the piezoelectric element 9 is arranged at a position where there is no displacement with respect to the pressure chamber 2.

In this case, the piezoelectric element 9 may be bonded to the concave portion 4, but if the piezoelectric material 29 is filled in the concave portion 4 to form the piezoelectric element 9, the manufacturing is easier. By aligning the pressure chamber 2 and the recess 4 on both surfaces of the silicon single crystal wafer 1 and performing etching,
It can be processed easily and accurately.

[0014]

Embodiments will be described with reference to the drawings. 1 to 7 show an inkjet head according to a first embodiment of the present invention and a manufacturing process thereof.

In FIG. 2, reference numeral 1 is a silicon single crystal wafer, and a pressure chamber 2 has an ink supply path 3 on one surface thereof.
Is formed to be recessed so as to communicate with the. The pressure chamber 2 and the ink supply path 3 are formed by anisotropic etching, for example.

On the other surface of the silicon single crystal wafer 1,
The concave portion 4 is formed in substantially the same size as the pressure chamber 2 in alignment with the pressure chamber 2. This recess 4 is also formed by anisotropic etching, for example.

At this time, for example, by using a mask eyeliner or the like, a mask for etching is placed on the surface of the silicon single crystal wafer 1 with a positional accuracy of several μm and the pressure chamber 2 is positioned.
It can be formed corresponding to the mask on the side.

The wall portion of the silicon single crystal wafer 1 forming the partition between the pressure chamber 2 and the recess 4 thus formed serves as the diaphragm 5 vibrated by the piezoelectric element 9 described later.

Although FIG. 2 shows one pressure chamber 2, as shown in FIG. 3, one silicon wafer 1 is used.
Is a size for forming a large number of inkjet heads 10 together, and one of the inkjet heads 10 is
4, a plurality of pressure chambers 2 ... Are formed in each ink jet head 10.

Next, as shown in FIG. 5, the entire surface of the silicon single crystal wafer 1 on the side where the concave portion 4 is formed,
For example, the aluminum electrode layer 6 is formed by vacuum vapor deposition. Further, as shown in FIG. 6, the piezoelectric element 9 having electrodes 9a and 9b formed on both front and back surfaces and having a size just fitted into the recess 4 is fitted into the recess 4 to thereby improve the conductivity. It is bonded and fixed there with an adhesive or the like.

By doing so, the lower electrodes 9a of all the piezoelectric elements 9 are provided with respect to the aluminum electrode layer 6.
And the aluminum electrode layer 6 can be used as a common electrode.

Finally, as shown in FIG. 1, a nozzle plate 8 made of, for example, a photosensitive glass material is provided with nozzle holes 7 on the surface of the silicon single crystal wafer 1 on which the pressure chamber 2 is formed. After bonding, the whole is divided and cut into each inkjet head 10 shown in FIG.

In the ink jet head 10 thus formed, a voltage is applied to both electrodes 9a and 9b to deform the piezoelectric element 9, whereby the vibrating plate 5 vibrates and pressure is applied to the ink in the pressure chamber 2. Is added, and the ink becomes an ink droplet and is ejected from the nozzle hole 7.

7 to 10 show an ink jet head of a second embodiment of the present invention and a manufacturing process thereof. However, the initial part of the manufacturing process is the same as the state shown in FIGS. 2 to 4 of the first embodiment.

In this embodiment, as shown in FIG. 2, when the pressure chambers 2 and the recesses 4 are aligned and formed on both surface sides of the silicon single crystal wafer 1 by aligning, respectively, it is shown in FIG. As described above, the nozzle plate 28 made of the silicon single crystal wafer having the nozzle holes 27 formed by the etching process is bonded to the surface of the silicon single crystal wafer 1 on the side where the pressure chamber 2 is formed. This joining can be performed by so-called direct joining by heating at 1100 ° C. for 30 minutes without using an adhesive or the like.

Then, as shown in FIG. 8, a platinum electrode layer 26 is formed on the entire surface of the silicon single crystal wafer 1 on which the concave portions 4 are formed by, for example, sputtering.
To form a lower electrode.

Next, as shown in FIG. 9, the piezoelectric paste 29 is filled in the concave portion 4 and dried, and then the piezoelectric element 9 is baked by heating at 1000 ° C. for 2 hours, for example. As the piezoelectric paste 29, for example, piezoelectric fine powder (PZ) made of lead oxide, zirconium oxide, and titanium oxide is used.
A mixture of T) and a binder for binding the powders to each other and an organic solvent is used.

When the piezoelectric element 9 is formed in the recess 4 in this way, as shown in FIG. 10, for example, silver paste is printed on the surface of the piezoelectric element 9 by screen printing so as not to contact the lower electrode 26. Then, it is dried to form the upper electrode 30.

With the configuration as in the second embodiment, the forming and mounting work of the piezoelectric element 9 can be greatly simplified and the manufacturing cost can be reduced.

[0030]

According to the ink jet head of the present invention, by fixing the piezoelectric element in the concave portion formed in alignment with the pressure chamber, the piezoelectric element can be arranged in the pressure chamber without displacement. As a result, the size and flying speed of the ejected ink droplets do not vary from nozzle to nozzle, and uniform and high-quality printing quality can be obtained.

[Brief description of drawings]

FIG. 1 is a front partial cross-sectional view of a first embodiment.

FIG. 2 is a front partial cross-sectional view showing the manufacturing process of the first embodiment.

FIG. 3 is an overall plan view showing a manufacturing process of the first embodiment.

FIG. 4 is a plan sectional view showing a manufacturing process of the first embodiment.

FIG. 5 is a front partial cross-sectional view showing the manufacturing process of the first embodiment.

FIG. 6 is a partial front sectional view showing the manufacturing process of the first embodiment.

FIG. 7 is a front partial cross-sectional view showing the manufacturing process of the second embodiment.

FIG. 8 is a front partial cross-sectional view showing the manufacturing process of the second embodiment.

FIG. 9 is a front partial cross-sectional view showing the manufacturing process of the second embodiment.

FIG. 10 is a front partial cross-sectional view of the second embodiment.

[Explanation of symbols]

 1 Silicon Single Crystal Wafer 2 Pressure Chamber 3 Ink Supply Path 4 Recess 5 Vibration Plate 9 Piezoelectric Element

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mineharu Tsukada 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor, Katsuharu Hida 1015, Kamedotachu, Nakahara-ku, Kawasaki, Kanagawa Prefecture, Fujitsu Limited

Claims (3)

[Claims] 1. An ink supply channel (3) is provided on one surface of a silicon single crystal wafer (1) for applying pressure for ejecting ink droplets from a nozzle hole (7) to ink contained therein. ) And a recessed portion (4) formed in a recessed portion on the other surface of the silicon single crystal wafer (1) so as to be aligned with the pressure chamber (2). ) And the diaphragm (5) formed by the wall of the silicon single crystal wafer (1) separating the recess (4) from the pressure chamber (2), the recess (). An ink jet head comprising a piezoelectric element (9) fixed to 4). 2. The piezoelectric element (9) is formed by filling the recess (4) with a piezoelectric material (29).
The described inkjet head. 3. The pressure chamber (2) and the recess (4) are
The ink jet head according to claim 1 or 2, wherein both sides of the silicon single crystal wafer (1) are aligned and formed by etching.