JPH05293961A - Ink jet head - Google Patents

Abstract

PURPOSE:To achieve rationalization by simultaneously assembling a plurality of vibrators while realizing the stable emission of an ink droplet by enhancing positional accuracy in a displacement direction at the time of the incorporation of a vibrator set and densifying nozzle arrangement. CONSTITUTION:In an ink jet head emitting ink by displacing the walls of pressure chambers in the displacement direction of vibrators 1, the positioning members 2 integrated with the vibrators 1 are provided and positioning parts 2a positioning the vibrators l are provided to at least a part of the positioning members and the vibrators 1 are arranged to the walls 5a of the pressure chambers on the basis of the positioning parts. The positioning parts are positioned on both sides of the vibrators arranged in a short-strip state and many vibrators are simultaneously arranged on the basis of the positioning parts.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art An ink jet head for displacing a pressure chamber wall in the displacement direction of a vibrator to pressurize ink in the pressure chamber and eject ink droplets from a nozzle communicating with the pressure chamber is disclosed in JP-A-58-1119870. The structure is shown in FIG.

However, in spite of the fact that the tip end position of the leg portion 21 attached to the vibrator 20 must be determined with high accuracy, the position of the tip end portion of the leg portion attached to the vibrator in the displacement direction during assembly in this type of structure. I don't know. As a result, the tip ends of the legs vary from one transducer to another, reducing variations in characteristics. In the bad case, the legs may not reach the diaphragm 25, and the displacement of the vibrator may not be transmitted to the diaphragm. Alternatively, the leg portion pushes the flexible diaphragm into a large area, causing the vibrator to be bent or bent due to the reaction force of the diaphragm, or the thin diaphragm to be cracked or damaged.

Further, in this type of structure in which each oscillator is surrounded and supported, the intervals between the oscillators are wide, and therefore the pressure chambers and nozzles cannot be arranged densely.

Further, since a plurality of vibrators are arranged one by one, the number of assembling steps is great.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and provides an ink jet head in which the positioning accuracy of the vibrator is high and the vibrators can be arranged in a high density, and the assembly is simplified. I will do it.

[0007]

Therefore, in the present invention, a vibrator for displacing the pressure chamber wall and a positioning member integrated with the vibrator are provided, and at least a part of the positioning member is provided with:
A positioning unit was provided that provided a position in the vibration displacement direction with respect to the vibrator.

Further, the positioning portions are positioned on at least both sides of the vibrators arranged at equal intervals. Moreover, one side of the vibrator is fixed by a positioning member, and the displacement is taken out from the other side.

[0009]

Embodiments will be described in detail below along with embodiments of the present invention. FIG. 1 is an exploded perspective view of an embodiment of an inkjet head according to the present invention, and FIG. 2 is a sectional view focusing on a certain flow path. The vibrator 1 has a plurality of strips, for example, 24 strips, formed in a strip shape with a pitch of 1/180 inch, and has two rows. One side of the vibrator 1 is fixed to a positioning member 2 having a U-shaped cutout 2b, and an unsupported portion of the other side is in the longitudinal direction of the vibrator 1 when power is supplied through the leads 3, that is, in the figure. It is displaced in the direction of arrow z. The positioning member 2 is firmly fixed to the housing 10 and functions as a fixing member that fixes one side of the vibrator.

The nozzle plate 4 has an ink droplet ejection nozzle 6
Are provided over two rows. The flow path plate 7 includes a rectangular pressure chamber 7a and an ink chamber 7b common to each pressure chamber.
If the nozzle plate 4 and the flow path plate 7 are laminated, each nozzle 6 communicates with each corresponding pressure chamber 7a. A closed flow path is formed by laminating the cover plate 5 which is also a pressure chamber wall on the flow path plate 7. According to the development example, the pressure chamber 7a has a width of 0.1.
mm, length 2 mm, depth 0.1 mm. Ink is supplied from an ink cartridge (not shown) to the ink chamber 7b through the pipe 8.

As shown in FIG. 2, the lid plate 5 covers the pressure chamber 7a and has a rectangular thick portion 5a of high rigidity for coupling with the vibrator tip 1a and the flexure caused by displacement of the vibrator 1. It consists of a thin portion 5b to be raised and a thick portion 5c in the periphery. The lid plate 5 is made of, for example, nickel electroforming, and the thin portion 5b has a thickness of 0.5.
μm to 3 μm, and the thick portions 5a and 5b are selected from the range of 10 to 100 μm. The cover plate 5 can be made separately into a thin portion and a thick portion, and for example, the thick portion can be formed by plating or a resin layer on a thin metal film.

After the vibrator 1 is integrated with the positioning member 2, an adhesive is applied to the vibrator tip 1a and a positioning portion 2a which will be described later, and then the positioning member 2 is preliminarily joined to the cover plate 5 on the housing 10. From the bottom in the figure along the slot 10a. Reference numeral 13 is a circuit board.

FIG. 3 is a cross-sectional view seen from the other direction, showing a state of the vibrator 1 arranged on the cover plate 5.

The positioning member 2 to which the vibrator 1 is fixed has 2
The positioning portion 2a is provided at one place, and the positioning portion 2 is provided.
a and the vibrator tip 1a are on the same plane. On the other hand, the thick portions 5a and 5c of the lid plate 5 are also on the same plane. To incorporate the vibrator, as described above, the vibrator tip 1a and the positioning portion 2 are used.
After the adhesive is applied to a, the positioning portion 2a is applied to the thick portion 5c of the cover plate from below in the figure to determine the position in the longitudinal direction of the vibrator, and the adhesive applied in that state is cured. At the same time, the positioning member 2 is poured into the housing 10 with an adhesive or mechanically fixed. It should be noted that no hollow portion such as a flow path is formed in the flow path portion that comes into contact with the positioning member so that the position can be determined without deformation even if a load is applied from the positioning member.

By providing the positioning portions 2a on both sides of a plurality of vibrators arranged at equal intervals, strip-shaped vibrators can be reliably set on the pressure chamber wall without tilting, and the positioning portions on both sides are vibrators. Protects brittle oscillators when assembled.

Further, the positioning member 2 is provided with a fixing function so that one side of the vibrator is fixed to the positioning member 2 and the displacement is taken out from the other side.

Further, as can be seen from the above, since a plurality of vibrators can be simultaneously and accurately incorporated, the assembly can be extremely rationalized.

Even with the above positioning structure,
Strictly speaking, since there is a component size error and an assembly error, there may be a gap between the vibrator tip 1a and the thick portion 5a of the cover plate 5, or conversely, the tip 1a may push the thick portion 5a into the pressure chamber side. .. However, according to this structure, the value was very small, and in our development example, the maximum gap was about 5 μm for both the gap and the indentation. The gap is filled with the applied adhesive so that there is no problem in the connection between the tip 1a and the thick portion 5b, and even when the thick portion 5a is pushed in, the thin portion 5b bends and the error is absorbed. The lid plate 5 does not cause stress destruction, and the vibrator does not bend or break.

Thin film electrodes 2v and 2w are formed in a pattern on the surface of the positioning member 2. The U-shaped thin metal plate 11 connects between the common electrode on each vibrator and the thin film electrode 2w, and the electrode of each vibrator is connected to the thin film electrode 2v. The lead 3 shown by is connected.

FIGS. 4A, 4B and 4C are perspective views showing the assembly of the vibrator 1 and the positioning member 2. The plate-shaped vibrator 1 is joined to the positioning member 2 to which the thin film electrode 2v is attached by an adhesive or brazing. Next, the vibrator and the positioning member are cut at the same time in the slicing machine using a rotary blade, a wire saw, or the like, or in the same step, in the direction of arrow 12 to make the tip position. That is, the vibrator tip 1a and the positioning portion 2a are aligned on the same plane with a slicing machine. Next, the vibrator and the thin film electrode on the positioning member are cut at the same time with a slicing machine to form the vibrator into strips and divide the thin film electrode to form the extraction electrode 2v for each vibrator. According to our development head, the transducers are arranged at a pitch of 1/180 inch, the dimensions are 70 μm width, 500 μm thickness,
The length was 5 mm. Further, in order to obtain a large displacement at a low voltage and to obtain the rigidity of the vibrator, a vibrator in which piezoelectric materials are laminated in multiple layers via electrodes is used. As the material of the positioning member 2, metal, plastic, or ceramic can be used.

As another assembling method, the vibrator and the positioning member may be joined in a state where the position of the vibrator tip and the position of the positioning portion are aligned using a jig, and then the vibrator is machined into a strip. It is possible.

FIG. 5 shows another embodiment of the vibrator 1 and the positioning member 2, in which the positioning portion 2a of the positioning member 2 is retracted from the vibrator tip 1a by a dimension g. When this oscillator is installed on the lid plate 5 from below in the figure, the tip 1a of the oscillator causes the lid plate 5 to be slightly forced into the pressure chamber. Therefore, even if the adhesive applied to the tip 1a is thin, the thick portion 5a and the tip 1 are
a is reliably joined. It is also possible to omit the adhesive when the cover plate 5 bends inward in all pressure chambers. FIG. 6 shows another embodiment in which the vibrator 1 is installed on the cover plate 5. The positioning portion 2a of the positioning member 2 is replaced with the positioning portion 1 of the housing 10.
The position of the tip 1a of the vibrator 1 is brought out by applying 0c.

Although the embodiment of the present invention has been described above, a fixing member for fixing the vibrator may be separately provided separately from the positioning member. Alternatively, the housing may be provided with a positioning member independently so as to function as a fixing member for the vibrator.

It is possible to attach a leg portion to the tip of the vibrator as in the conventional example, and in that case, the positioning portion 2a is set to the tip of the leg portion.

[0025]

As described above, the ink jet head according to the present invention is provided with the vibrator and the positioning member integrated with the vibrator, and the positioning member has a positioning portion positioned with respect to the tip of the vibrator. Formed. Then, the oscillator is pressed against the wall of the pressure chamber with the positioning portion as a reference to assemble. Therefore, (1) Since the tip of the vibrator can be positioned with high accuracy,
The tip of the oscillator, which was a problem in the past, separates from the pressure chamber wall,
Alternatively, the problem that the thin vibrator is bent or bent due to the pressure chamber wall being pushed too deeply and the thin portion of the lid plate is broken can be solved.

(2) Moreover, not only the positions are determined with high accuracy, but also the positions of a plurality of vibrators are determined based on the same positioning portion reference, so that there is no variation between the vibrators and ink droplets are ejected from each nozzle. As a result, excellent recording quality is possible.

(3) The support member having the positioning portion has a high degree of freedom in material and shape and is excellent in strength, and since it does not break or bend even when pressed, not only the assembly accuracy is improved, but also easy to assemble. It also made it possible to assemble a machine roughly.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an inkjet head of the present invention.

FIG. 2 is a partial cross-sectional view of the inkjet head of the present invention.

FIG. 3 is a partial cross-sectional view of the inkjet head of the present invention.

4A to 4C are perspective views for explaining a vibrator and a positioning member of the inkjet head of the present invention.

FIG. 5 is an explanatory view showing another example of the vibrator and the positioning member of the inkjet head of the present invention.

FIG. 6 is an explanatory diagram of another positioning structure of the vibrator of the inkjet head of the present invention.

FIG. 7 is an explanatory diagram of a conventional inkjet head.

[Explanation of symbols]

 1 vibrator 1a vibrator tip 2 positioning member 2a positioning part 4 nozzle plate 5 cover plate 5a thick part of cover plate corresponding to pressure chamber 5b thin part of cover plate 5c thick part of cover plate around pressure chamber 6 nozzle 7 flow path plate 7a pressure chamber 7b common ink chamber 10 housing

Claims (3)

[Claims] 1. An ink jet head for displacing a pressure chamber wall in a displacement direction of a vibrator to pressurize ink in the pressure chamber and eject ink droplets from a nozzle communicating with the pressure chamber, the ink jet head being integrated with the vibrator. Equipped with a simplified positioning member,
An inkjet head, characterized in that at least a part of the positioning member is provided with a positioning portion that is positioned with respect to the vibrator in a vibration displacement direction. 2. The ink jet head according to claim 1, wherein the positioning portions are located on at least both sides of a plurality of transducers arranged at equal intervals. 3. The ink jet head according to claim 1, wherein the positioning member fixes one side of the vibrator.