Dark decay control system utilizing two electrostatic voltmeters
CA 2076838 C · Owner: Hurwitch, Carl B. · Inventors: Macdonald, Daniel W.; Hurwitch, Carl B.; Berman, Robin E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A single pass tri-level imaging apparatus and method. Compensation for the effects of dark decay on the background voltage V Mod, and the color toner patch, V tc readings is provided using two ESVs (ESV1 and ESV2), the former located prior to the color or DAD housing and the latter after it. Since the CAD and black toner patch voltages are measured (using ESV2) after dark decay and CAD voltage loss have occurred, no compensation for these readings is required. The DAD image voltage suffers little dark decay change over the life of the P/R so the average dark decay can be built into the voltage target.
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 August 25, 1992 and granted February 16, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 25, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 25, 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.