(12) United States Patent ao) Patent No.: us 6,190,003 Bi
Sato et al. (45) Date of Patent: *Feb. 20,2001
(54) ELECTROSTATIC ACTUATOR AND
MANUFACTURING METHOD THEREFOR
(75) Inventors: Kazuhiko Sato; Hiroyuki Maruyama;
Masahiro Fujii; Tadaaki Hagata; Kqji
Kitahara; Keiichi Mukaiyama, all of
(73) Assignee: Seiko Epson Corporation, Tokyo (JP)
( * ) Notice: This patent issued on a continued prosecution application filed under 37 CFR 1.53(d), and is subject to the twenty year patent term provisions of 35 U.S.C. 154(a)(2).
Under 35 U.S.C. 154(b), the term of this patent shall be extended for 0 days.
(21) Appl. No.: 08/993,788
(22) Filed: Dec. 19, 1997
(30) Foreign Application Priority Data
Dec. 20, 1996 (JP) 8-342213
Oct. 16, 1997 (JP) 9-284127
(51) Int. C I. B41J 2/06
(52) U.S. C I 347/54
(58) Field of Search 347/54, 55, 9,
347/10, 11, 68, 69, 70, 71, 72, 50, 40;
(56) References Cited
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5,144.340 * 9/1992 Hotomi et al
5,331,454 7/1994 Hornbeck .
5,501,870 3/1996 Shiraishi et al. .
5,534.900 * 7/1996 Ohno et al
An electrostatic actuator comprising opposing electrode members displaced relatively by an electrostatic force is provided with improved durability so that electrostatic attraction between opposing members does not drop and the opposing electrode members do not stick together. Hydrophobic films of hexamefhyldisilazane (HMDS) are formed on a surface of segment electrode and a bottom surface of a diaphragm (common electrode) of an eletrostatic actuator wherein the diaphragm forms a wall of an ink chamber in an ink jet head. HMDS molecules are smaller than PFDA molecules, and a uniform, variation-free hydrophobic film can therefore be formed even when the gap between opposing electrodes is narrow. Durability and film stability of a HMDS hydrophobic film are also high. An electrostatic actuator with high durability and operating stability can thus be achieved.
17 Claims, 11 Drawing Sheets