The installation failed with a message about "gs-esp" being a dependency, but gs-esp doesn't seem to be a supported package any more.
So I went on a search and tried out "lenny", which apparently is an implementation or contains gs-esp. This did the trick: the Canon printer drivers then installed without a problem.
To install this package (on Linux Mint):
sudo dpkg -i gs-esp_8.62.dfsg.1-3.2lenny5_all.deb