(19)
(11) EP 0 673 774 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
21.02.1996 Bulletin 1996/08

(43) Date of publication A2:
27.09.1995 Bulletin 1995/39

(21) Application number: 95103031.1

(22) Date of filing: 03.03.1995
(51) International Patent Classification (IPC)6: B41J 2/36
(84) Designated Contracting States:
DE FR GB

(30) Priority: 25.03.1994 US 218486

(71) Applicant: EASTMAN KODAK COMPANY
Rochester, New York 14650-2201 (US)

(72) Inventor:
  • Jeanmaire, David Louis, c/o Eastman Kodak Company
    Rochester, New York 14650-2201 (US)

(74) Representative: Blickle, K. Werner, Dipl.-Ing. et al
KODAK AKTIENGESELLSCHAFT Patentabteilung
70323 Stuttgart
70323 Stuttgart (DE)


(56) References cited: : 
   
       


    (54) Compensation for voltage drops due to resistive heating element location in thermal printer heads


    (57) Compensation is provided for location-dependent voltage drops within a thermal printhead by adjusting the duration of application of current to selected resistive heating elements as a function of the location of (i) the resistive heating elements on the printhead and (ii) of the number of heating elements which are simultaneously activated. A histogram of the frequency that different duration of current application occur during each print line is produced and used for producing a location-dependent correction factor. The resistive heating elements may be segmented into a plurality of groups based on physical location on the printhead, and the duration of application of current to the selected resistive heating elements is adjusted as a group.






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