JPH05512A - Production of ink jet head - Google Patents

Abstract

PURPOSE:To perform high-density wiring to realize a high printing quality and to lower a cost by directly bonding an aluminum wire on a piezoelectric element provided with a plated electrode. CONSTITUTION:The full surface of a piezoelectric element 1 serving as a vibration source is bonded to a conductive film 6 of a vibration plate 7 as a component of a flow path through an adhesive layer 5. The expansion/contraction of the piezoelectric element 1 in both directions is converted to the vertical vibration, whereby a pressure fluctuation is produced in a pressure chamber 9. The electric conduction of the conductive film 6 is ensured by the surface roughness of the piezoelectric element 1. The conductive film 6 forms an electrode common to the other piezoelectric elements. A conductive substrate 4 supplying an electric power to the piezoelectric element 1 is fixed with the adhesive layer 5 in the vicinity of the piezoelectric element 1 and connected to the piezoelectric element 1 through an aluminum wire 3. In this manner, an electric power can be supplied to the piezoelectric element through a simple- form conductive plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an ink jet head.

[0002]

2. Description of the Related Art FIGS. 4 and 5 show the structure of a conventional ink jet head.

Vibration of the piezoelectric element 1 is transmitted to the pressure chamber 9, and ink is ejected from a nozzle communicating with the pressure chamber 9. In such an inkjet head, one surface of the piezoelectric element 1 is bonded to the diaphragm 7 having the conductive film 6 via the adhesive layer 5. The bonding of the conductive substrate 4 for supplying electric power to the other surface of the piezoelectric element 1 does not hinder the behavior of the piezoelectric element 1.
They are joined by a conductive material such as the solder 10 and the conductive rubber 12. FIG. 4 shows soldering, and FIG. 5 shows conductive rubber.

However, in the case of soldering, deterioration of piezoelectric characteristics due to heating, deterioration of insulation due to scattering of solder material, and poor conduction due to poor soldering are likely to occur. When the piezoelectric elements are mounted at a high density, stable joining with all the piezoelectric elements is difficult.

On the other hand, in the case of the conductive rubber, the conductive rubber 12 and the fixing member 13 are required as separate parts, and the increase in the number of parts and the accompanying increase in cost have been unavoidable.

Further, as shown in FIG. 6, when the piezoelectric elements are arranged in a plurality of rows, the drawing of the conductive substrate becomes complicated, which causes an increase in component cost.

[0007]

SUMMARY OF THE INVENTION According to the present invention, a high-density wiring for realizing high printing quality is possible in a joining process of a piezoelectric element and a conductive substrate in a manufacturing process of an ink jet head, and a low cost ink jet. An object is to provide a method for manufacturing a head.

[0008]

SUMMARY OF THE INVENTION The main feature of the present invention is to directly connect an aluminum wire to a piezoelectric element provided with a plated electrode so as to connect with a conductive substrate.

[0009]

FIG. 1 shows an embodiment of a method for manufacturing an ink jet head according to the present invention.

The piezoelectric element 1 which is the vibration source is entirely bonded to the conductive film 6 of the diaphragm 7 which is one member constituting the flow path by the adhesive layer 5, so that the expansion and contraction of the piezoelectric element 1 in the plane direction can be performed in the vertical direction. Is converted into the vibration of the pressure chamber 9 to cause pressure fluctuation in the pressure chamber 9. Since the present invention is a mounting method of an electric system, description of the flow path system is omitted.

The conductive film 6 ensures electrical continuity due to the surface roughness of the piezoelectric element 1 and constitutes an electrode common to other piezoelectric elements. A conductive substrate 4 that supplies electric power to the piezoelectric element 1 is fixed near the piezoelectric element 1 with an adhesive layer 5, and is connected to the piezoelectric element 1 by an aluminum wire 3.

Up to now, it has been difficult to obtain sufficient bonding strength because the surface electrode 2 of the piezoelectric element 1 is usually a vapor deposition film. However, by changing the surface electrode 2 to a plating film, Aluminum wire 3 directly to the surface
Can be bonded. The power consumption of the piezoelectric element is very small, and even an aluminum wire having a diameter of about 0.3 mm can ensure sufficient capacity. or,
In general, in the case of inkjet heads, multiple piezoelectric elements are often mounted at high density. Even in such cases, the shape of the conductive substrate is restricted by the position and arrangement of the piezoelectric elements by taking advantage of the freedom of wire bonding. It is possible to connect the piezoelectric element and the conductive substrate without receiving them.
The bonding work can be performed at a high speed of about 0.5 seconds per place by using a commercially available bonding device. In addition, wedge bonding by ultrasonic vibration is
Since it can be performed without applying a load such as heating to the component, it is possible to prevent deterioration of the piezoelectric characteristics due to heating and deformation of the component such as the vibration plate or the flow path substrate.

FIG. 2 shows an embodiment in which the piezoelectric elements 1 are not arranged in a straight line. Since the direction of the aluminum wire 3 at the time of bonding can be freely set, even if the piezoelectric element 1 is not arranged in such a straight line, the connection can be made without making the shape of the conductive substrate 4 complicated.

FIG. 3 shows an embodiment in which the piezoelectric elements 1 are arranged in a plurality of rows. The length of the aluminum wire at the time of bonding is 5-8m in case of 0.3mm diameter wire.
Since m is possible, the conductive substrate 4 can be connected by pulling out in a single direction even when the piezoelectric elements 1 are arranged in a plurality of rows, and can be manufactured with the same configuration as in the case of a single row.
In addition, by unifying the conductive substrate 4 in a single direction, it is possible to realize a significant reduction in component cost as compared with the case of bidirectionally drawing.

[0015]

As described above, according to the present invention,
The piezoelectric element and the conductive substrate are joined by aluminum wire bonding. As a result, even if the piezoelectric elements are arranged in a complicated and high density, it is possible to supply the electric power to the piezoelectric elements with the conductive substrate having a simple shape. The simple shape of the conductive substrate can reduce the cost of parts, and since there is no restriction on the arrangement of the piezoelectric elements on the power supply, it is possible to design the optimum flow path for the print head. In addition, since the wedge bonding by ultrasonic vibration can be performed without applying a load such as heating to the parts, it is possible to prevent the deterioration of the piezoelectric characteristics and the deformation of the parts due to the heating and improve the assembly accuracy. it can.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of an inkjet head manufactured by a manufacturing method according to the present invention.

FIG. 2 is an explanatory diagram showing an example of an ink jet head manufactured by the manufacturing method according to the present invention when the arrangement of piezoelectric elements is not linear.

FIG. 3 is an explanatory diagram showing an example of an ink jet head when the piezoelectric elements are arranged in a plurality of rows, which is manufactured by the manufacturing method according to the present invention.

FIG. 4 is an explanatory view showing a conventional method of joining a piezoelectric element of an inkjet head and a conductive substrate by soldering.

FIG. 5 is an explanatory diagram showing a method of joining a piezoelectric element of an inkjet head and a conductive substrate by using a conductive rubber of a conventional manufacturing method.

FIG. 6 is an explanatory diagram showing a method of joining a piezoelectric element and a conductive substrate in an inkjet head when the piezoelectric element is arranged in a plurality of rows by soldering, which is a conventional manufacturing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric element 2 Surface electrode (plating film) 3 Aluminum wire 4 Conductive substrate 5 Adhesive layer 6 Conductive film 7 Vibration plate 8 Flow path substrate 9 Pressure chamber 10 Solder 11 Heating member (heater / laser light) 12 Conductive rubber 13 Fixing member

Claims (1)

Claim: What is claimed is: 1. A method of manufacturing an ink jet head, wherein vibration of a vibration source is transmitted to a pressure chamber via a vibration plate, and ink is ejected from a nozzle communicating with the pressure chamber. A method for manufacturing an inkjet head, characterized in that a piezoelectric element and a conductive substrate for supplying electric power to the piezoelectric element are joined by wedge bonding with an aluminum wire.