(19)
(11) EP 0 628 412 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
07.06.1995 Bulletin 1995/23

(43) Date of publication A2:
14.12.1994 Bulletin 1994/50

(21) Application number: 94202383.9

(22) Date of filing: 22.03.1990
(51) International Patent Classification (IPC)5: B41J 2/115, B41J 2/12, B41J 2/02
(84) Designated Contracting States:
CH DE ES FR GB IT LI NL SE

(30) Priority: 31.03.1989 US 332009

(62) Application number of the earlier application in accordance with Art. 76 EPC:
90303101.1 / 0390427

(71) Applicant: VIDEOJET SYSTEMS INTERNATIONAL, INC.
Wood Dale, Illinois 60191-1073 (US)

(72) Inventors:
  • Pickell, James Robert
    Bartlett, Illinois (US)
  • Keur, Robert Irvin
    Niles, Illinois (US)
  • Clark, James Eugene
    Naperville, Illinois (US)

(74) Representative: Goddin, Jeremy Robert 
The General Electric Company plc GEC Patent Department Waterhouse Lane
Chelmsford, Essex CM1 2QX
Chelmsford, Essex CM1 2QX (GB)


(56) References cited: : 
   
     
    Remarks:
    This application was filed on 23 - 08 - 1994 as a divisional application to the application mentioned under INID code 60.
     


    (54) Nozzle drive control system and method for ink jet printing


    (57) A method of, and a control circuit for, determining the exciting voltage to be applied to the nozzle of an ink jet printer to break a stream of ink into droplets for printing includes the steps of slowly increasing the exciting voltage from a minimum value and detecting and recording the value C(H) at which droplet formation first occurs closest to the nozzle. The exciting voltage for printing is estimated by applying electrical test patterns (Figure 6) to the ink droplets such that the patterns will vary in phase relative to droplet timing whereby only some of the test patterns will successfully charge the droplets. After that, those droplets which have been successfully charged are detected and the value C(H) determined from the change in the sequence of detected charge patterns. The exciting voltage for printing is estimated according to the formula

    , where E is a voltage related to the performance on the ink.






    Search report