To edit it, open up a terminal and then enter the following on the
sudo gedit /etc/samba/smb.conf
The problem was solved by selecting System -> Administration -> Printing
-> Server settings and ticking the box 'Share published printers
connected to this system'. I have never seen this before. There appears
to be something new every six months.
Ahh I see. I did notice that the Printer application had changed since
the last release.