It turns out the
issue was my the ufw firewall.
In the notes for Sane.pixma.5 at http://www.sane-project.org/man/sane-pixma.5.html
it explains that I need to open port 8612 in both directions so sane
could see the scanner. I did that and now all works well.
I am running Mint 18.1 64-bit on an Asus UX305UA laptop. I have a
Canon MG7720 on my network and have installed the Canon printer
drivers from cnijfilter2 (v 5.20) and scangearmp2 (v 3.2).
I have no problems printing from any program or scanning with the
the Canon
