JPH0760973A - Inkjet head - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide an inkjet head used for an inkjet printer, which can secure the directionality and stability of flying particles, improve the speed, and reduce the driving voltage. The inkjet head 21 includes a pressure chamber 8 and a flow channel plate 10 having an ink supply channel 9 for supplying ink to the pressure chamber 8, a nozzle plate 23 having nozzles communicating with the pressure chamber 8, and a flow channel plate. A driving body 13 such as a piezoelectric element is provided on the pressure chamber 8 so as to face the pressure chamber 8. The nozzle has a shape of two or more layers, and adjacent layers have different nozzle shapes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drop-on-demand type ink jet head used in an ink jet printer for recording by directly ejecting and adhering ink particles onto a recording medium.

[0002]

2. Description of the Related Art In an ink jet printer, ink is ejected by an ink jet head having an ink ejecting mechanism and the ink is adhered onto a recording medium to form recording dots. FIG. 3 shows an outline of an inkjet printer, 1 is an inkjet head, 2 is a platen, 3 is an ink tank, and 4 is an ink pipe connecting the inkjet head 1 and the ink tank 3. The inkjet head 1 is mounted on a carrier 7 which is guided by guides 5 and 6 and reciprocates along the platen 2, and operates at a predetermined time to perform printing.

The main structure of the ink jet head 1 is shown in FIG.
As shown in FIG.
And a flow path plate 10 having an ink supply path 9 for supplying ink to the pressure chamber 8, and a nozzle plate 12 having nozzles 11.
And a piezoelectric element (driving body) 13. The ink supply path 9 of the flow path plate 10 receives the supply of ink from the ink pipe 4 of FIG.

The nozzle plate 12 is joined to one surface of the flow path plate 10 on the side where the pressure chamber 8 is formed, and in this state, the nozzle 11 communicates with the pressure chamber 8. The piezoelectric element 13 is bonded to a portion of the other surface of the flow path plate 10 that faces the pressure chamber 8. The portion where the piezoelectric element 13 is mounted on the flow path plate 10 serves as a vibration plate.

The above-mentioned ink ejection will be described in more detail with reference to FIG. 4. During printing, a voltage is applied to the piezoelectric element 13 for a predetermined time. As a result, the piezoelectric element 13 deforms, the pressure of the ink in the pressure chamber 8 rises, and the ink is ejected from the nozzle 11.

The shape of the nozzle includes a tapered shape and a straight shape. The taper nozzle 11A is shown in FIG.
It is tapered as shown in FIG. The shape of the taper nozzle 11A is, for example, a square having an inlet of 200 μm on a side, an outlet having a square of 50 μm on a side, and a nozzle length of 106 μm. Also, the straight nozzle 11B is
It has a straight shape as shown in FIG. The straight nozzle 11B has, for example, a nozzle diameter of 5
The nozzle length is 0 μm and the nozzle length is 200 μm.

[0007]

When the taper nozzle is used, since the shape is tapered, the flow path resistance is low and the energy loss is not so large. Therefore, the volume of flying particles is large, but the velocity is slower. Further, since the nozzle length is not sufficiently long, the flight direction varies and the stability is poor. The straight nozzle has been used before the taper nozzle was adopted. In this case, the flight direction, stability and speed are superior to those of the taper nozzle.
Since the flow path is rapidly reduced, flow path resistance is increased and particle volume is reduced.

Therefore, the conventional straight nozzles and taper nozzles have a problem that it is difficult to reduce the driving voltage and reduce the cost.

It is an object of the present invention to provide an ink jet head which can improve the directionality, stability and speed of flying particles and can reduce the driving voltage.

[0010]

In order to achieve the above object, the present invention has a flow channel plate having a pressure chamber and an ink supply path for supplying ink to the pressure chamber, and a nozzle communicating with the pressure chamber. In an inkjet head used as a printing mechanism of an inkjet printer, the nozzle is composed of a nozzle plate joined to the flow channel plate and a driver provided on the flow channel plate so as to face the pressure chamber. The configuration (first configuration) is characterized by having a shape of two or more layers.

Further, in the ink jet head having the above-mentioned first structure, nozzles having different shapes in adjacent layers are used (second structure).

[0012]

As described above, in the present invention, since the multi-taper nozzles having different shapes in the adjacent layers are incorporated in the nozzle portion, when the particles under the same conditions as those of the conventional taper nozzle and straight nozzle are made to fly, the It becomes possible to drive by voltage.

[0013]

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

FIG. 1 is a partially cutaway perspective view showing an essential part of the ink jet head of this embodiment.
Is joined to the flow channel plate 10 having a pressure chamber 8 and a flow channel plate 10 having an ink supply path 9 for supplying ink to the pressure chamber 8 and a multi-taper nozzle (nozzle) 22 communicating with the pressure chamber 8. A nozzle plate 23 and a piezoelectric element (driving body) 13 which is bonded on the flow path plate 10 so as to face the pressure chamber 8.

The multi-taper nozzle 22 is shown in FIG.
As shown, there are two or more layers (in this figure, the case of four layers is shown.
Have the shape of Specifically, the nozzle plate 23
But the first layer plate 23₁And the second layer plate 23₂And the third layer
Board 23₃And the plate 23 of the fourth layer _FourIt is composed by joining and
The multi-taper nozzle 22 has a plate 23₁Formed in
Straight nozzle 22₁And plate 23₂Formed on the
Panuzzle 22₂And plate 23₃Straight formed on
Cheat 22₃And plate 23_FourTaper nozzle 22 formed on
_FourIt is formed by.

Each nozzle 22 ₁ , 22 ₂ , 22 ₃ , 22 ₄
Are continuously formed with their centers aligned as shown.
Since the multi-taper nozzle 22 has the above-described configuration, it has the characteristics of both the conventional taper nozzle and the straight nozzle. Therefore, it becomes possible to jet particles having a target particle velocity and volume with good directionality and stability. Further, the driving voltage can be reduced. As a result of the experiment, it was possible to fly particles for forming 360 dpi.

FIG. 2B shows another example of the multi-taper nozzle. The multi-taper nozzle 24 has a second layer on the third layer.
This is different from the previous example in that a taper nozzle 24 ₃ having an inverse taper with the layer is formed. 24 ₁ is a straight nozzle, 24
₂ and 24 ₄ are taper nozzles.

Also in the case of this example, the same effect as the preceding example can be obtained.

[0019]

As described above, according to the present invention, the multi-taper nozzle is used in the nozzle portion of the ink jet head so that the particles having the desired particle velocity and volume can fly with good directionality and stability. It is possible. In addition, the required drive voltage of the driving body can be reduced.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing a main part of an inkjet head according to an embodiment of the present invention.

FIG. 2 is a shape explanatory view of a multi-taper nozzle according to an embodiment of the present invention, and FIGS. 2A and 2B show multi-taper nozzles having different shapes.

FIG. 3 is a perspective view showing an outline of an inkjet printer.

FIG. 4 is a partially cutaway perspective view showing a main part of a conventional inkjet head.

FIG. 5 is an explanatory view of various shapes of a conventional nozzle, and FIG.
Shows a taper nozzle, and FIG. 5 (B) shows a straight nozzle.

[Explanation of symbols]

 8 Pressure Chamber 9 Ink Supply Path 10 Flow Path Plate 13 Piezoelectric Element (Drive Body) 21 Inkjet Head 22,24 Multi Taper Nozzle

Claims (2)

[Claims] 1. A flow channel plate having a pressure chamber and an ink supply path for supplying ink to the pressure chamber; a nozzle plate having nozzles communicating with the pressure chamber and joined to the flow channel plate; An ink jet head used as a printing mechanism of an ink jet printer, comprising: a driving member provided on the road plate so as to face the pressure chamber, wherein the nozzle has a shape of two or more layers. . 2. The ink jet head according to claim 1, wherein nozzles having different shapes in adjacent layers are used.