Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1999-09-13
2001-08-14
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S068000, C347S070000, C347S071000
Reexamination Certificate
active
06273558
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a piezoelectric vibrator unit in which internal electrodes are stacked in parallel with the expansion/contraction axis, and more particularly to the structure of internal electrodes, and also to an ink jet recording head.
As disclosed in Japanese Patent Publication No. 4-1052A, in an ink jet recording head using a piezoelectric vibrator of the longitudinal vibration mode, an elastic plate is placed via a small gap on the back face of a nozzle plate in which plural nozzles are opened, and piezoelectric vibrators having the piezoelectric constant d31, which are obtained by dividing so as to correspond to respective pressure generating chambers of a channel substrate, abuts against the back face of the elastic plate. Ink in a reservoir is guided into the pressure generating chambers via associated ink supply ports, and the ink is then pressurized by the piezoelectric vibrators which are driven by a recording signal, thereby causing the ink to be ejected from the nozzle orifices.
As disclosed in Japanese Patent Publication No. 7-195688A, for example, such a piezoelectric vibrator is configured in the following manner. It is prepared a single piezoelectric diaphragm in which common electrodes and internal individual electrodes are alternately stacked on each other while sandwiching a piezoelectric material therebetween. In the piezoelectric diaphragm, the internal common electrodes are exposed from a rear end face on the side of the fixed end, and the internal individual electrodes are exposed from a front end face on the side of the free end. The piezoelectric diaphragm is divided such that dummy piezoelectric vibrators are arranged in both sides thereof, and driving piezoelectric vibrators are formed into a comb-like shape in the central portion thereof so that their non-vibrating regions are continuous.
The internal individual electrodes are connected to a segment electrode which elongates from the front end face to a top face of a non-vibrating region, and the internal common electrodes to a common electrode which elongates from the rear end face to the top face of the non-vibrating region. A driving signal is supplied to the segment electrode and the common electrode via a flexible cable.
As described above, the external electrodes, which constitute the segment electrode and the common electrode, are formed in an L-like shape on the two faces, i.e., the end faces and the top face. Therefore, there arise problems in that conductive failure easily occurs in a conductive layer in the interface between the end face and the top face, and hence the formation of the conductive layer requires much labor, and that corner edges tend to be broken and a connection failure thereby occurs, thereby lowering the production yield.
SUMMARY OF THE INVENTION
The invention has been conducted in view of these problems. It is a first object of the present invention to provide a piezoelectric vibrator unit in which, even when corner edges are slightly broken, the conduction relationship is ensured.
It is a second object of the present invention to provide a method of manufacturing such a piezoelectric vibrator unit.
It is a third object of the present invention to provide an ink jet recording head incorporating such a piezoelectric vibrator unit.
In order to solve the problems, according to the present invention, there are fixed on a fixing substrate a plurality of piezoelectric vibrators in which internal individual electrodes and internal common electrodes are alternately and overlappingly stacked on each other while sandwiching piezoelectric materials therebetween in an area where is to be a vibrating region thereof, comprising: a through hole piercing through the piezoelectric materials in at least one end portions thereof for being filled with a conductive material such that at least either the first conductive layers or the second conductive layers are connected with each other; and an external electrode layer formed on one surface in a longitudinal direction of the piezoelectric vibrators for connecting the conductive material in the through hole.
The conductive layers on the internal individual electrodes or the internal common electrodes constituting the piezoelectric vibrators are electrically connected with each other and drawn out to a the top face in the longitudinal direction thereof via the through holes arranged inner than the end faces of the piezoelectric vibrators. Therefore, it is not necessary to form conductive layers on the end faces or the corner edge where such a layer is hardly formed.
REFERENCES:
patent: 5350969 (1994-09-01), Gattuso
patent: 5444471 (1995-08-01), Usui et al.
patent: 4-1052 (1992-01-01), None
patent: 7-195688 (1995-08-01), None
Barlow John
Do An H.
Seiko Epson Corporation
Sughrue Mion Zinn Macpeak & Seas, PLLC
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