ok I tried this fix which came from later in the thread and it worked for me... my canon mx922 printer is now working
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copy/then delete from CUPs folder (/usr/libexec/cups )
to some new folder somewhere ( desktop )
reboot
copy back from folder to /usr/libexec/cups
reboot
open sys prefs, go to printers and scanners. highlight existing printer, right mouse click and choose reset option.
restart your printer (physically disconnect from power, wait, restart)
then... add the printer back again.
restarting the printer (power down, power up), wasn't required the 2nd time I tried this.
crazy that this workaround works, but okay, it does.