Circuit for driving liquid drop spraying apparatus

(19)

(11)

EP 1 078 748 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	16.05.2001 Bulletin 2001/20

(43)	Date of publication A2:
	28.02.2001 Bulletin 2001/09

(21)	Application number: 00307095.0

(22)	Date of filing: 18.08.2000

(51)	International Patent Classification (IPC)⁷: B41J 2/045

(84)	Designated Contracting States:
	AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
	Designated Extension States:
	AL LT LV MK RO SI

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Priority:

20.08.1999 JP 23444599
28.07.2000 JP 2000229485

(71)	Applicant: NGK INSULATORS, LTD.
	Nagoya-City, Aichi Prefecture 467-8530 (JP)

(72)	Inventors:
	Ohnishi, Takao, c/o NGK Insulators, Ltd Nagoya-shi, Aichi-ken 467-8530 (JP) Ohwada, Iwao, c/o NGK Insulators, Ltd Nagoya-shi, Aichi-ken 467-8530 (JP) Hirota, Toshikazu, c/o NGK Insulators, Ltd Nagoya-shi, Aichi-ken 467-8530 (JP)

(74)	Representative: Paget, Hugh Charles Edward et al
	MEWBURN ELLIS York House 23 Kingsway London WC2B 6HP London WC2B 6HP (GB)

(54)	Circuit for driving liquid drop spraying apparatus

(57) In a circuit for driving a liquid drop spraying or ejecting apparatus, a coil (L1) is provided in series with a resistor (R1) that determines charge characteristics of a charge circuit (12) of a piezoelectric/electrostrictive element (1), thereby making gentle start characteristics when a charge voltage rises. In addition, discharge circuits are provided at two stages. A constant of the second discharging circuit (13b) is set to be smaller than a constant of the first discharging circuit (13a). Coils (L2) and (L3) are provided in series at resistors (R2) and (R3) that determine their discharge characteristics. In this manner, even in the case where a large amount of liquid is sprayed, the driving circuit is capable of smoothly supplying liquid to a pressurizing chamber.

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