My advice would be to simply disable cups.
sudo mv /etc/init/cups.conf /etc/cups.conf.disabled
Or you could edit /etc/inti/cups.conf and comment out the start line (s).
#start on (filesystem
# and (started dbus or runlevel )
# and stopped udevtrigger)
stop on runlevel 
Alternately you can remove cups, but probably , at least IMO, more hassle then it is worth.
CUPS is your printing service. The first command stops the service from running.
The link I gave you discusses Upstart. A service is a process that runs in the background, usually waiting for connections. In the case of cups, cups = Common Unix Printing System http://www.cups.org/ and it will share your printer if you configure it to do so. Upstart is the process which monitors, starts, and stops various services.
You could as easily simply remove cups and sane (sane is for scanners), but probably more hassle then it is worth.
It is highly unlikely cups or sane is consuming significant resources or in any way slowing down your performance.
If, as you gain experience with Ubuntu / Linux, you wish a smaller, lighter system, it is IMO far easier to start with a minimal install and build up then start with a standard desktop install and start removing things.
If you are new to Ubuntu and Linux, take care in removing things you do not yet understand.