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Expired Canadian patentCanada

Color electrophotographic method

CA 2003424 C · Owner: Kumashiro, Yoshimasa · Inventors: Kumashiro, Yoshimasa; Murakami, Hajime

CIPO record

Overview

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

Disclosed is a color electrophotographic method according to which color images of high quality can be stably obtained by digital signal processing of image information. This method comprises converting a read image signal to a digital signal, subjecting the digital signal to signal processing which includes tone correction of photoreceptor and tone correction of toner color density, exposing charged photoreceptor with a light having intensity modulated according to the signal to form a electrostatic latent image and then developing the latent image.

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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.

Why it's free to use

  • Filed November 21, 1989 and granted August 13, 1996. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 21, 2009.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 21, 2011.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledNovember 21, 1989
GrantedAugust 13, 1996
Term endedNovember 21, 2009
Patent numberCA 2003424 C
Classification (IPC)G03G13/01 +2 more

Timeline

Timeline From CIPO dates

1990199219941996199820002002200420062008Application filedNov 21, 1989Patent grantedAug 13, 1996Term endedNov 21, 2009

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.