Rewritable recording device
CA 2107907 C · Owner: Yamada, Keiki · Inventors: Yamada, Keiki; Ohnishi, Masaru
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A conventional rewritable recording device utilizing a heat-sensitive recording medium which is turned into a colored state when heated at a first predetermined temperature and turned into a colorless state when heated at a second predetermined temperature has a problem that the recording medium will not be turned into a completely colorless state depending on the history of recording and erasing, when, for example, no satisfatory heating to the second predetermined temperature is performed or when repeated recording and erasing have deprived the recording medium of its reversibility. In order to solve this problem the invention device is provided with a data erasing means wherein the …
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 February 8, 1993 and granted May 11, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 8, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 8, 2015.
- 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.