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Expired Canadian patentCanada

Magnetic disk coating method and apparatus

CA 1256328 A · Owner: International Business Machines Corporation · Inventors: Hagan, James A.; Wilke, Myron A.W.; Maloy, James E.

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Abstract From the Canadian patent

A rigid magnetic disk substrate is spin coated using a closely confining, stationary air barrier adjacent the surface being coated. The coating is applied through a slotted opening in the air barrier which is progressively closed as the coating is applied and completely sealed during the spin-off operation. During the application of the coating the air, barrier is positioned approximately 0.15 inch from the disk substrate surface and prior to spin-off, the barrier is moved to a position 0.025 inch from the coated surface. Further, during the high speed spin-off cycle a high kinematic viscosity gas, such as helium is introduced into, the space between the barrier and the coated surface to …

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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 June 27, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended June 27, 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.
FiledAugust 8, 1985
GrantedJune 27, 1989
Term endedJune 27, 2006
Patent numberCA 1256328 A
Classification (IPC)G11B5/84 +2 more

Timeline

Timeline From CIPO dates

1986198919921995199820012004Application filedAug 8, 1985Patent grantedJune 27, 1989Term endedJune 27, 2006

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