https://wiki.gentoo.org/wiki/Canon_ Pixma_ Printer found suggestions on canon printer driver support, hoping to support "imagerunner c3120"
net-print/cnijfilter does not exist in the gentoo repository. I don't know what that wiki page is referring to.
The wiki page https://wiki.gentoo.org/wiki/Canon_Printer (renamed) is a try to gather in a single place all the information related to the driver packages, because Canon has an unusual versioning of the driver sources (non cumulative versions - one given printer model is supported by only one version). @cnfczn: You should query the Canon support web site for the exact version of the driver sources, then search in the overlays if someone still maintains the relevant ebuild (https://gpo.zugaina.org). I just added the "imageRunner C series" and the requested model in the wiki page.
Is https://bugs.gentoo.org/791394 the same driver?