Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-01-24
2003-12-23
Nguyen, Judy (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S071000, C347S072000, C347S068000
Reexamination Certificate
active
06666547
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording head in which a piezoelectric vibrator of a longitudinal vibration mode is used as a driving source, and more particularly to a structure of an elastic plate which receives a pressure due to a displacement of a piezoelectric vibrator, and also to a method of producing such a plate.
In order to improve the recording density, the pitch of nozzle opening rows tends to be reduced. To comply with this tendency, a single crystal silicon wafer is isotropically etched, and a nozzle plate and an elastic plate which are produced another method are fixed to the etched wafer, thereby configuring a channel unit. A displacement of a piezoelectric vibrator is transmitted to the channel unit so as to produce a pressure in a pressure generating chamber, and an ink droplet is ejected from a nozzle opening by the pressure.
When pressure generating chambers are arranged in high density, each of the pressure generating chambers has a very small width. In order to cause the whole of the longitudinal direction of a pressure generating chamber to be efficiently deformed, therefore, a configuration is employed in which a convex portion, or a so-called island portion that elongates in the longitudinal direction of the pressure generating chamber is formed on the surface of the elastic plate, and the displacement of the piezoelectric vibrator is transmitted via the island portion to a wide region of the elastic plate sealing the pressure generating chamber.
It has been proposed that a polymer film or a metal thin plate is used as such an elastic plate, a metal plate member, for example, a stainless steel plate which has a relatively large thickness so as to ensure the rigidity of the elastic plate is laminated onto the surface of the elastic plate, and the stainless steel plate is etched, thereby forming an island portion which transmits a displacement of a piezoelectric vibrator to the whole of a pressure generating chamber, and a diaphragm portion which is elastically deformed by the displacement of the island portion to change the capacity of the pressure generating chamber (WO93/25390).
However, this proposed configuration has the following problem. The coefficient of thermal expansion of the plate member serving as the elastic plate, particularly a polymer film is largely different from that of the metal plate for ensuring the rigidity. Furthermore, heat applied during the production process causes polymer materials to shrink. During the process of producing the channel unit, therefore, the plate member is flexurally deformed and a positional error occurs between the plate member and a channel forming substrate.
SUMMARY OF THE INVENTION
The invention has been conducted in view of the problem. It is an object of the invention to provide an ink jet recording head in which deformation of a plate member during a production process can be suppressed as far as possible, whereby the production process can be simplified.
It is a second object of the invention to provide a method of producing such a plate member.
A plate member according to the present invention is configured by a substantially rectangular base member of a laminated structure including an elastic plate and a rolled metal plate that are laminated with each other. The elastic plate is elastically deformable by an external pressure, and has an ink resistance. The rolled metal plate is produced by rolling an etchable metal material. A longitudinal direction of the base member is perpendicular to a rolling direction of the rolled metal plate.
Usually, the rigidity of a metal material is large in a direction perpendicular to the rolling direction. Therefore, warpage which is likely to occur in the longitudinal direction is suppressed by the rigidity that is enhanced by the directionality of rolling.
An ink jet recording head according to an embodiment includes a nozzle opening, a pressure generating chamber, a reservoir, and an ink supply port. At least the pressure generating chamber or the reservoir is sealed by a plate member which is partly elastically deformable. The plate member is configured by a substantially rectangular base member in which an elastic plate that can be elastically deformed by an external pressure, and that has an ink resistance, and a rolled metal plate that is produced by rolling an etchable metal material are laminated with each other. A longitudinal direction of the base member is perpendicular to a rolling direction of the rolled metal plate. Therefore, the rigidity in the direction perpendicular to the rolling direction is large, warpage which easily occurs in the longitudinal direction can be suppressed by the rigidity that is enhanced by the directionality of rolling, and the positioning accuracy in an assembly process can be ensured.
The present disclosure relates to the subject matter contained in Japanese patent application Nos. Hei. 11-21450 (filed on Jan. 29, 1999), and Hei. 11-329241 (filed on Nov. 19, 1999), which are expressly incorporated herein by reference in their entireties.
REFERENCES:
patent: 4574445 (1986-03-01), Bentin et al.
patent: 4846747 (1989-07-01), Higashinakagawa et al.
patent: 5008689 (1991-04-01), Pan et al.
patent: 5604522 (1997-02-01), Miura et al.
patent: 5963234 (1999-10-01), Miyazawa et al.
patent: 0 616 890 (1994-09-01), None
patent: WO 93/25390 (1993-12-01), None
Japanese Abstract No. 10193612, dated Jul. 28, 1998.
An Encyclopædia of Metallurgy and Materials, C. R. Tottle, p. 73 Dictionary of Metallurgy, Colin D. Brown.
Furuhata Atsushi
Takahashi Tomoaki
Watanabe Minoru
Nguyen Judy
Seiko Epson Corporation
Sughrue & Mion, PLLC
Tran Ly T
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