JPH05338146A - Ink jet head - Google Patents

Abstract

PURPOSE:To jet ink from a nozzle by driving a piezoelectric element effectively with a micro applying signal by a method wherein the piezoelectric element is fixed at both ends to two opposed wall surfaces in an ink liquid passage. CONSTITUTION:A piezoelectric element 101 is arranged by being fixed to opposed wall surfaces of a first substrate 102 and a second substrate 103 which compose an ink liquid passage 107.

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 having an improved method of arranging piezoelectric elements in an on-demand ink jet head.

[0002]

2. Description of the Related Art Conventionally, as a method of disposing a piezoelectric element of an ink jet head, there is a method as disclosed in Japanese Patent Laid-Open No. 1-128839. The constituent elements include a vibration unit including a piezoelectric element and an elastic plate, an ink liquid flow path, and a nozzle. The piezoelectric element and the elastic plate are connected to each other, and the elastic plate is arranged so as to face the ink liquid flow path, and one end of the elastic plate is fixed and supported so as to be a cantilever at the piezoelectric element fixing portion on the opposite side of the nozzle. hand,
It is adapted to be displaced in the direction perpendicular to the ink liquid flow path.

When a print signal is applied to the piezoelectric element, the vibration unit is displaced and bends, causing a change in volume of the ink liquid flow path and ejecting ink from the nozzle.

[0004]

However, in the above-mentioned conventional technique, the displacement amount of the piezoelectric element is small with respect to the signal applied to the piezoelectric element, and therefore, in order to eject ink from the nozzle, the applied signal must be increased. However, there was a problem that the efficiency was low. In order to solve such a drawback, it is an object of the present invention to provide a method for fixing a piezoelectric element that causes more volume change in an ink liquid flow path with a minute applied signal.

[0005]

An ink jet head of the present invention has a piezoelectric element, and transfers the displacement of the piezoelectric element corresponding to a print signal applied to the piezoelectric element to the ink liquid as a pressure displacement, In an inkjet head in which ink is ejected from nozzles, the piezoelectric element is fixed on both wall surfaces facing each other in the ink liquid flow path.

[0006]

According to the above configuration of the present invention, the piezoelectric element is displaced by applying a minute applied signal to the piezoelectric element,
Printing is performed by ejecting ink from nozzles by displacing the volume in the ink liquid flow path.

[0007]

EXAMPLE An example of the present invention will be described below by an ink jet method generally called a hitting method. The piezoelectric element arranging method of the present invention can be applied to one having an inkjet head structure in which the displacement of the piezoelectric element is transmitted to the ink liquid (recording liquid) as a pressure displacement to eject the ink from the nozzle. ..

FIG. 1 is a sectional view in a first embodiment of the present invention, and FIG. 2 is a side sectional view. The configuration is shown using FIG. There are a first substrate 102 and a second substrate 103 that form an ink liquid flow path 107 as components, and in the ink liquid flow path 107, a supply port 104 to which ink is supplied, a cavity portion 105 serving as an ink pool, and an ink. Of the nozzle 106. Cavity wall surface 2 places 10
5A and 105B have two cavity wall surfaces 105.
Piezoelectric elements 101 having a thickness sufficient to be fixed at both ends of A and 105B are arranged. In addition, the piezoelectric element 10
Electrodes are wired at two locations on the fixed side end surface of 1.

The piezoelectric element 101 has a conical shape, a cylindrical shape, a prismatic shape, a pyramidal shape or the like. In this embodiment, the cylindrical piezoelectric element 101 is used. The piezoelectric element 101 is the side surface 1 of the first substrate 102.
05A and the side surface 105B of the second substrate 103, both ends of which are fixed, and one electrode of the fixed side end surface of the piezoelectric element 101 and the electrode 1
08, and the other electrode of the piezoelectric element 101 and the electrode 10.
9 are in contact with each other so that conduction can be achieved. The second substrate 103 is made of an elastic member, and is polycarbonate, polysulfone, thin glass or the like in this embodiment.

The second substrate 103 is a piezoelectric element 101.
In consideration of the contraction and expansion, the structure is such that the elasticity of the second substrate 103 constantly applies pressure to the piezoelectric element 101. With such a structure, when the piezoelectric element 101 contracts or expands, the piezoelectric element 101 is always in contact with the first substrate 102 and the second substrate 103, and both ends can be fixed. Since the piezoelectric element is fixed by the pressure of the first substrate and the second substrate, there is basically no need for conventional joining methods such as adhesion, welding, and fusion, but by using these methods, reliability can be improved. High bonding is possible.

Next, the operation of the first embodiment of the present invention will be described with reference to FIGS. The piezoelectric element 101 contracts in the C direction of FIG. 1 by a positive (or negative) applied signal, deforms the second substrate 103 as shown in FIG. 3, and reduces the volume of the cavity portion 105. By applying a negative (or positive) applied signal to the piezoelectric element 101, the piezoelectric element 101 is expanded as shown in FIG.
Supply to. Again, the applied signal should be positive (or negative) as shown in FIG.
By contracting the piezoelectric element 101, the volume of the cavity 105 is rapidly changed, and ink is ejected from the nozzle 106. Ink is ejected from the nozzle 106 by such a series of operations, but the displacement of the piezoelectric element 101 is changed by the second substrate 103 in comparison with the conventional technique of causing the volume change of the cavity only by the displacement of the piezoelectric element. The amplification can change the internal volume of the larger cavity 105.

Next, a second embodiment will be described. FIG. 6 is a sectional view of the second embodiment. Further, FIG. 7 shows a side sectional view of the second embodiment. The constituent elements are the same as in the second embodiment. As a main feature, the piezoelectric element 601 is used whose width in the thickness direction of the piezoelectric element is sufficiently smaller than the height of the cavity portion. Both sides of the thin piezoelectric element 601 have electrodes 601A, 60
1B is formed, and the piezoelectric element 601 is formed by an applied signal.
Expands and contracts in the length direction. The piezoelectric element 601 is slightly curved in a fixed state, and both ends thereof are system-stopped by system stop parts 610 and 611 provided in the cavity part 605. The electrode 601B of the piezoelectric element 601 is in contact with the electrode 602B of the first substrate 602 to establish conduction. Further, the electrode 601A of the piezoelectric element 601 is the piezoelectric element projection 6
At 12, the electrode 603B of the second substrate 603 is in contact with the second substrate 603 to establish electrical continuity.

Next, the operating principle of the second embodiment will be described with reference to FIGS. By applying a positive (or negative) applied signal to the piezoelectric element 601, the piezoelectric element 601 contracts in the D direction of FIG. Similar to the first embodiment, the second substrate 603 has a structure in which the elasticity of the second substrate 603 constantly applies pressure to the piezoelectric element 601 in consideration of contraction / compression of the piezoelectric element 601, so that the structure shown in FIG. And the volume of the cavity portion 605 is reduced. Next, when the applied signal of the piezoelectric element 601 is made negative (or positive), the piezoelectric element 601 expands in the direction E in FIG.
Since the piezoelectric element 601 is deformed as shown in FIG. 9 and the volume of the cavity portion 605 is increased, the ink liquid is supplied from the supply port 604 to the cavity portion 605. Again, by making the applied signal positive (or negative) and contracting the piezoelectric element 601, as shown in FIG. Ink is ejected from the nozzle 106 by such a series of operations. Since the piezoelectric element is thinner than that of the first embodiment, it is generally possible to operate with a lower applied signal.

[0014]

As described above, according to the present invention, by fixing the piezoelectric element arranged in the head on the opposite wall surfaces of the flow path, it is possible to increase the number of minute applied signals with a minute applied signal. The volume change in the ink liquid flow path can be generated, and the ink can be efficiently ejected from the nozzle. As a result, the amount of displacement of the piezoelectric element with respect to the signal applied to the piezoelectric element, which is a problem to be solved by the invention, is small, and the volume change in the ink liquid flow path is sufficient to eject ink from the nozzle. In order to generate, the applied signal must be increased, and the problem of poor efficiency is solved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of an inkjet head of the present invention.

FIG. 2 is a side sectional view showing the first embodiment of the inkjet head of the present invention.

FIG. 3 is a sectional view showing the operation of the first embodiment of the inkjet head of the present invention.

FIG. 4 is a sectional view showing the operation of the first embodiment of the inkjet head of the present invention.

FIG. 5 is a sectional view showing the operation of the first embodiment of the inkjet head of the present invention.

FIG. 6 is a cross-sectional view showing a second embodiment of the inkjet head of the present invention.

FIG. 7 is a side sectional view showing a second embodiment of the inkjet head of the present invention.

FIG. 8 is a sectional view showing the operation of the second embodiment of the inkjet head of the present invention.

FIG. 9 is a sectional view showing the operation of the second embodiment of the inkjet head of the present invention.

FIG. 10 is a sectional view showing the operation of the second embodiment of the inkjet head of the present invention.

[Explanation of symbols]

 101,601 Piezoelectric element 102,602 First substrate 103,603 Second substrate 104,604 Supply port 105,605 Cavity portion 105A, 105B Cavity portion wall surface 108,109 Electrode 602B, 603B Electrode 106,606 Nozzle 107 Ink liquid flow path 601A, 601B Electrodes 610, 611 System stop 612 Piezoelectric element protrusion

Claims (1)

[Claims] 1. An ink jet head having a piezoelectric element, wherein displacement of the piezoelectric element generated in response to a print signal applied to the piezoelectric element is transmitted as pressure displacement to an ink liquid to eject ink from a nozzle. 2. An ink-jet head, wherein the piezoelectric element is fixed on both wall surfaces facing each other in the ink liquid flow path.