(19)
(11) EP 0 671 271 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
07.08.1996 Bulletin 1996/32

(43) Date of publication A2:
13.09.1995 Bulletin 1995/37

(21) Application number: 95103252.3

(22) Date of filing: 07.03.1995
(51) International Patent Classification (IPC)6B41J 2/145
(84) Designated Contracting States:
CH DE FR GB IT LI NL SE

(30) Priority: 09.03.1994 JP 38733/94

(71) Applicant: SEIKO EPSON CORPORATION
Shinjuku-ku Tokyo 163 (JP)

(72) Inventors:
  • Fujii, Masahiro
    Suwa-shi, Nagano-ken, 392 (JP)
  • Mukaiyama, Keiichi
    Suwa-shi, Nagano-ken, 392 (JP)
  • Maruyama, Hiroyuki
    Suwa-shi, Nagano-ken, 392 (JP)
  • Hagata, Tadaaki
    Suwa-shi, Nagano-ken, 392 (JP)

(74) Representative: Hoffmann, Eckart, Dipl.-Ing. 
Patentanwalt, Bahnhofstrasse 103
82166 Gräfelfing
82166 Gräfelfing (DE)

   


(54) Ink jet recording apparatus


(57) An inkjet recording apparatus comprises an inkjet head (10) having for each of one or more nozzles (4) an ink passage (7, 6) in communication with the nozzle (4) and an electrostatic actuator. The actuator includes a diaphragm (5) provided at one part (6) of the ink passage, a nozzle electrode (21) provided in opposition to the diaphragm (5) with a gap (G) in between and a vibration chamber (9) having upper and lower walls of which one wall is formed by one part of said diaphragm (5), while said nozzle electrode is attached to the other wall. The diaphragm constitutes one and the nozzle electrode (21) the other plate of a capacitor. Drive means selectively charge and discharge each actuator such as to displace its diaphragm (5) by electrostatic force, thereby to eject ink droplets from said one or more nozzles. Vibration chamber (9) is sealed to be airtight. Its volume V is such that the ratio between this volume V and the volume ΔV displaced by the diaphragm is within the range

. This enables sufficient electrostatic attraction with a sealed actuator and without necessity to increase the drive voltage.







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