JP3672049B2 - Circuit connection method for drive element of inkjet print head - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a circuit connection method for a drive element for an ink jet print head using an electro-mechanical conversion element (hereinafter referred to as a piezo) as an ink discharge means.
[0002]
[Prior art]
As described below, the conventional inkjet printhead circuit connection method is to attach a contact material to a drive element (hereinafter referred to as piezo) so as to conduct, and cut it together when the piezo is cut to create individual electrodes. It was.
[0003]
FIG. 1 shows a state in which a piezo 1 is bonded and fixed to a ceramic substrate 2.
[0004]
FIG. 2 shows a state in which an electrode member (made of copper alloy) 3 constituting an individual electrode is bonded to and fixed to the piezo 1 in the state shown in FIG.
[0005]
As shown in FIG. 3, an individual electrode is formed by cutting with a dicer so that the piezo 1 and the electrode member 3 are individually divided, and one piezo is also divided and cut individually, whereby each nozzle is paired with each nozzle. It works as a corresponding drive element.
[0006]
Thereafter, the electrode member 3 ′ in FIG. 3 is connected to the relay substrate 4 after relaying to the main body substrate, and finally the common electrode 13 is separately connected.
[0007]
[Problems to be solved by the invention]
In the processing described above, the cutting performance of the piezoelectric 1 and the ceramic substrate 2 is similar, cutting performance of the electrode member 3 are different. This difference, that is, the extreme difference in hardness machinability of the material between the piezo and the individual electrode material, makes cutting difficult and makes it difficult to increase the cutting efficiency .
[0008]
[Means for Solving the Problems]
The above-described problem is that an electromechanical conversion element is bonded and fixed on a substrate, cut at a predetermined pitch, and further connected to the electromechanical conversion element with a cable. In the processing method, the process of applying plating on the board before bonding the electromechanical conversion element on the board and the process of pressing and connecting the flexible board to the board by micro bump bonding method when connecting the cable were added. in particular Ri is achieved good.
[0009]
Further, this is achieved by mounting a head drive circuit on a flexible substrate and reducing the number of wirings connected to the substrate.
[0010]
[Action]
According to said structure, the electrical connection of the individual electrode of a piezo with a very small pitch can be performed easily. In addition, the piezo can be cut quickly and at an ideal speed.
[0011]
【Example】
The present invention will be described below.
[0012]
First, as shown in FIG. 4, the piezo 5 is bonded and fixed to the ceramic substrate 6. The surface of the ceramic substrate 6 is plated, and is bonded and fixed so as to be electrically connected to the piezo 5.
[0013]
Next, as shown in FIG. 5, the thing of the state of FIG. 4 is cut. At this time, the plating is cut to form individual electrodes.
[0014]
Next, as shown in FIG. 6, after aligning the flexible substrate 7, it is crimped and fixed to the ceramic substrate 6 'to take electrical conduction with each piezo 5'.
[0015]
This conduction method is either a method of pressing the contact of 7b to the individual electrode 6 'by microbump bonding as shown in FIG. 8 and maintaining conduction by the contraction stress of the resin 9, or 7b as shown in FIG. There is a method in which a bead 11 coated with an insulating film is put on a contact point together with an adhesive resin 10, and the insulating film of the bead is broken by pressure bonding so that 7b and 6 'are electrically connected.
[0016]
The common electrode 8 is produced in the same manner.
[0017]
Here, the bare chip of the drive circuit of the piezo 5 ′ is mounted on the flexible substrate 7, and the number of circuits corresponding to the number of heads is reduced and coupled to 7 a that is connected to the connector terminal. Such a configuration can also be easily achieved.
[0018]
A plurality of heads manufactured in this way can be arranged to form an ink jet print head as shown in FIG. In FIG. 7, 19 is an ink and 20 is a recording medium such as paper.
[0019]
【The invention's effect】
By doing so, it is relatively easy to determine the conditions for simultaneously processing the piezo and the ceramic substrate, and the cutting efficiency is good, so that the processing efficiency is increased. In addition, since the flexible substrate can be directly and simply attached, the number of processing steps is small and the cost is low. In addition, it is possible to reduce the number of connectors by incorporating a circuit such as a bare chip of a head drive circuit into this flexible substrate.
[0020]
This has an effect of improving the handling when the number of heads is increased to make a large head .
[Brief description of the drawings]
FIG. 1 is a perspective view showing a bonding state between a conventional piezo and a ceramic.
FIG. 2 is a perspective view showing a mounting state of a conventional electrode member.
FIG. 3 is a perspective view showing a conventional individual electrode molding state.
FIG. 4 is a perspective view showing a bonding state between a piezo and a ceramic according to the present invention.
FIG. 5 is a perspective view showing a state of forming individual electrodes of piezo and ceramic in the present invention.
FIG. 6 is a perspective view showing a wiring state of a piezo according to the present invention.
FIG. 7 is an assembly state diagram of a piezo head according to the present invention.
FIG. 8 is a schematic diagram showing a contact state of a wiring board in the present invention.
FIG. 9 is a schematic diagram showing a contact state of a wiring board in a second embodiment of the present invention.
[Explanation of symbols]
5 is a piezo, 6 is a ceramic substrate, 7 is a flexible substrate, 8 is a common electrode, 9 and 10 are resins, and 11 is a bead.

Claims (2)

In a method for processing an ink jet print head drive element formed by bonding and fixing an electromechanical conversion element on a substrate, cutting the electromechanical conversion element at a predetermined pitch, and further connecting the electromechanical conversion element with a cable. Before the electromechanical transducer is bonded and fixed, a process of applying plating to the board and a process of pressing and connecting the flexible board to the board by micro bump bonding method when connecting the cable are added. A circuit connection method for driving elements of an ink jet print head. 2. The circuit connection method according to claim 1, wherein a head drive circuit is mounted on a flexible substrate to reduce the number of wirings connected to the substrate.

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