I followed the instructions I was given for refilling my Dell 3000cn toner cartridges to the letter. They didn’t work. The printer kept telling me over and over again to replace the toner cartridge I’d refilled.
I finally got it to accept the refilled cartridge by enabling the “non-dell toner” option. To do this, hit the Menu button on the printer, select “Configure”, select “Maintenance”, select “Non-Dell Toner”, and set the value to “On”.
Just blogging this in case it turns out to be useful to somebody else (if it does, post a comment!).