(19)
(11) EP 0 427 199 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
05.06.1991 Bulletin 1991/23

(43) Date of publication A2:
15.05.1991 Bulletin 1991/20

(21) Application number: 90121213.4

(22) Date of filing: 06.11.1990
(51) International Patent Classification (IPC)5G03G 9/107, G03G 9/087
(84) Designated Contracting States:
BE DE FR GB NL

(30) Priority: 08.11.1989 US 433248

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

(72) Inventors:
  • Spence, John M., c/o EASTMAN KODAK COMPANY
    Rochester, New York 14650-2201 (US)
  • Contois, Robert E., c/o EASTMAN KODAK COMPANY
    Rochester, New York 14650-2201 (US)
  • DeMejo, Lawrence P., c/o EASTMAN KODAK COMPANY
    Rochester, New York 14650-2201 (US)

(74) Representative: Brandes, Jürgen, Dr. rer. nat. et al
Wuesthoff & Wuesthoff Patent- und Rechtsanwälte Schweigerstrasse 2
81541 München
81541 München (DE)


(56) References cited: : 
   
       


    (54) Two-component magnetic developer for magnetic image character recognition


    (57) A two-component type magnetic developer and its use in electrostatographic processes for generating documents suitable for magnetic image character recognition is described. The developer comprises a mixture of a magnetic carrier and a magnetic toner comprising particles of a binder resin medium and a magnetic material dispersed in the binder resin medium. The magnetic carrier is composed of acicular magnetic stainless steel particles containing a chromium content of at least 9 percent by weight which have been passivated to form a chromium-rich, stable film on the particle surfaces. The magnetic carrier in the developer provides magnetic image character recognition images and characters of excellent magnetic image character recognition readable quality and developed images of excellent image density and sharpness.





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