ufr2-printer-driver-us : CUPS driver (US edition) for Canon printers whose PCL is UFR II ( http://usa.canon.com/cusa/support/consumer/printers_multifunction/imageclass_series/imageclass_mf4890dw#DriversAndSoftware )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a chemoelectric
For Paludis use this rsync : rsync://gentoo.zugaina.org/chemoelectric-portage
If you have a problem : ycarus(-at-)zugaina.org