(19) |
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(11) |
EP 0 427 199 A3 |
(12) |
EUROPEAN PATENT APPLICATION |
(88) |
Date of publication A3: |
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05.06.1991 Bulletin 1991/23 |
(43) |
Date of publication A2: |
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15.05.1991 Bulletin 1991/20 |
(22) |
Date of filing: 06.11.1990 |
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(84) |
Designated Contracting States: |
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BE DE FR GB NL |
(30) |
Priority: |
08.11.1989 US 433248
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(71) |
Applicant: EASTMAN KODAK COMPANY |
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Rochester,
New York 14650-2201 (US) |
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(72) |
Inventors: |
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- 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)
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(74) |
Representative: Brandes, Jürgen, Dr. rer. nat. et al |
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Wuesthoff & Wuesthoff
Patent- und Rechtsanwälte
Schweigerstrasse 2 81541 München 81541 München (DE) |
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(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.