(19)
(11) EP 0 454 133 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
13.01.1993 Bulletin 1993/02

(43) Date of publication A2:
30.10.1991 Bulletin 1991/44

(21) Application number: 91106720.5

(22) Date of filing: 25.04.1991
(51) International Patent Classification (IPC)5: H01C 17/22, B41J 2/345
(84) Designated Contracting States:
DE FR GB

(30) Priority: 26.04.1990 JP 113879/90
26.04.1990 JP 113880/90

(71) Applicant: MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
Kadoma-shi, Osaka-fu, 571 (JP)

(72) Inventors:
  • Yoshiike, Nobuyuki
    Ikoma City, 630-01 (JP)
  • Watanabe, Yoshihiro
    Asahi-ku, Osaka City 535 (JP)

(74) Representative: Dr. Elisabeth Jung Dr. Jürgen Schirdewahn Dipl.-Ing. Claus Gernhardt 
Postfach 40 14 68
80714 München
80714 München (DE)


(56) References cited: : 
   
       


    (54) Thermal print head trimming apparatus and method for trimming resistance of a thermal print head


    (57) A thermal print head trimming apparatus trims the resistances of heating resistor elements (4a). The apparatus divides the measured resistance data into plural groups by their variation range, and applies pulse signal of high-voltage by a probe electrode (6) to the heating resistor elements (4a) in the plural groups except a group that includes the lowest resistance values of the heating resistor elements (4a). Thereby the whole resistances of the heating resistor elements (4a) in the thermal print head are trimmed to agree with the lowest resistance values.






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