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Expired Canadian patentCanada

Full tone electrophotographic imaging system

CA 1249945 A · Owner: Cheng, Stephen P.M. · Inventors: Cheng, Stephen P.M.

CIPO record

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

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Abstract From the Canadian patent

A method of producing an electrostatic charge image comprising the sequential steps of: (1) bringing an electrode into proximity with a photoreceptor, the photoreceptor having a dielectric substrate and a photoconductive film intimately bonded to the substrate, the electrode having means to enable an electric field to be applied across the photoreceptor and being adapted to be brought into proximity with the substrate of the photoreceptor along a length of the electrode and charging the photoreceptor with an electrostatic charge of one polarity and projecting an image of a photograph on the photoreceptor (2) charging the, photoreceptor with an electrostatic charge of opposite polarity and …

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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

  • Granted February 14, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended February 14, 2006.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledOctober 10, 1985
GrantedFebruary 14, 1989
Term endedFebruary 14, 2006
Patent numberCA 1249945 A
Classification (IPC)G03G15/02 +2 more

Timeline

Timeline From CIPO dates

1986198919921995199820012004Application filedOct 10, 1985Patent grantedFeb 14, 1989Term endedFeb 14, 2006

Sources & verification

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