Magnetic toner, image forming method, surface-modified fine silica powder and process for its production
CA 2062382 C · Owner: Uchiyama, Masaki · Inventors: Akashi, Yasutaka; Jo, Yoshinobu; Uchiyama, Masaki
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A magnetic toner has magnetic resin particles containing at least a binder resin, a charge control agent and a magnetic powder. The surface-modified fine silica powder being a fine silica powder has been treated with a hydrophobicizing agent. The fine silica powder has a specific surface area of not less than 180 m2/g, a hydrophobicity of from 60 % to 95 % and a bulk density of from 35 g/lit, to 49 g/lit.
Read the whole patent
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 March 6, 1992 and granted November 23, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 6, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 6, 2014.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.