Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1997-04-11
2001-04-17
Fuller, Benjamin R. (Department: 2855)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06217158
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a piezoelectric vibrator unit suitable for an ink jet recording head and an ink jet recording head using the piezoelectric vibrator unit. In particular, the present invention relates to a piezoelectric vibrator unit having curved portions which correspond to deformable regions of the vibrator unit.
2. Description of the Related Art
An actuator unit in which minute regions (arrayed at fixed pitches) are deflected is disclosed in Japanese Patent Laid-Open Publication No. Sho. 58-7364. The actuator unit includes a lower electrode, formed on the surface of a thin plate, which is elastically deformable. A green sheet, which is shaped like a rectangular strip and made of piezoelectric material, is layered on the thin plate surface with the lower electrode by bonding or coating. The resultant structure is sintered to form a piezoelectric layer. In addition, upper electrodes are formed on the surface of the sintered structure.
However, the bonding or coating process, by which the rectangular green sheet made of piezoelectric material is layered on the thin plate's surface is an essential step in the manufacture of the above-mentioned actuator unit. Therefore, the manufacturing of the actuator unit is inefficient. Furthermore, the lower electrode is easily peeled away from the piezoelectric layer in the sintering process. In this respect, the actuator unit is poor in durability.
To cope with this, a unique actuator unit is proposed in Japanese Patent Laid-Open Publication No. Sho. 62-101455. The actuator unit includes a thin elastic plate made of ceramic which has an electromechanical displacing property. A ceramic piece is inserted in a region of the elastic plate which is to be deflected. In addition, electrodes are attached to both sides of the region containing the ceramic piece.
The actuator unit described above eliminates the need for the bonding or coating process associated with the green sheet of piezoelectric material. In addition, the piezoelectric member has a single layer structure. Therefore, it rarely happens that the electrode is peeled away. However, the actuator unit has the following disadvantage. An elasticity and a rigidity of a vibrating region of the elastic plate are substantially equal to those in a non-vibrating region. Therefore, a displacement of the vibrated region by its deflection is small. Accordingly, when the actuator unit is applied to an ink jet recording head in which the volume of the pressure generating chamber is varied in order to discharge an ink droplet, a high voltage is required in order to drive the recording head.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the present invention to provide a piezoelectric vibrator unit having a single layer structure that allows for a greater displacement of the vibrating plate. Advantageously, the piezoelectric vibrator unit may be manufactured without any bonding or coating process for forming a piezoelectric member.
Another object of the present invention is to provide a method of manufacturing the piezoelectric vibrator unit.
Still another object of the present invention is to provide an ink jet recording head using the piezoelectric vibrator unit.
In order to carry out the above and other objects of the invention, a piezoelectric vibrator unit is provided in accordance with a first embodiment of the present invention. The piezoelectric vibrator unit includes an elastically deformable plate made of piezoelectric material having curved positions lengthwise arrayed at fixed pitches. A common electrode is formed on one side of the elastic plate, while discrete electrodes are formed on the curved portions of the elastic plate.
An extension and a contraction of the elastic plate are converted into deflection displacements that are made in conformity with a shape of each curved portion. Advantageously, the piezoelectric vibrator unit may be included in an ink jet recording head in which a pressure generating chamber is included. A rate of change of the volume of the pressure generating chamber per unit drive voltage is increased by employing the above mentioned elastically deformable plate having the curved portions instead of a vibrator unit including a flat plate.
REFERENCES:
patent: 4358781 (1982-11-01), Yamamori et al.
patent: 4383264 (1983-05-01), Lewis
patent: 4588998 (1986-05-01), Yamamuro et al.
patent: 4742365 (1988-05-01), Bartky et al.
patent: 4766671 (1988-08-01), Utsumi et al.
patent: 4825227 (1989-04-01), Fischbeck et al.
patent: 5266964 (1993-11-01), Takahashi et al.
patent: 5495137 (1996-02-01), Park et al.
patent: 5812163 (1998-09-01), Wong
patent: 5856837 (1999-01-01), Kitahara et al.
patent: 58-7364 (1983-01-01), None
patent: 62-101455 (1987-05-01), None
patent: 5-261921 (1993-10-01), None
patent: 6-40030 (1994-02-01), None
Kanaya Munehide
Usui Minoru
Dickens C.
Fuller Benjamin R.
Seiko Epson Corporation
Sughrue Mion Zinn Macpeak & Seas, PLLC
LandOfFree
Layered type ink jet recording head with improved... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Layered type ink jet recording head with improved..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Layered type ink jet recording head with improved... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2443477