Today, i wanted to print something, but i noticed the printer is not responding to my request. It seems the latest CUPS in -Current has made some changes so that it didn't detect my printer anymore (it's a major upgrade after all). I have tried to remove my printer and re-adding it again, but i'm stuck with this error message: Bad device-uri "cnij_usb:/dev/usb/lp0"!
When i read this thread in LQ, i realized that i didn't have the same problem (the problem in LQ did happened on my workstation at my office where i got a blank paper instead of a text). So, i searched for solution on the Internet and i got to Gentoo BugZilla which said about cnijfilter-common 3.00 package. Mine is 2.7.0 which i got from official repository of Canon.
I searched the Internet and got this package (3.00) from Canon Asia Support and i converted it to tgz using rpm2tgz application provided in Slackware and i removed the old cnijfilter-common package and install this new package. Next, i restarted my CUPS service and i'm able to get my printer working again after re-adding it again.
The correct device URI is supposed to be cnijusb:/dev/usb/lp0 which is fixed with the latest cnijfilter-common package.
I hope this helps when you encounter a problem with Canon printers and you are using CUPS 1.4.x.