Why would someone put their printer on the internet???? I really don't know, but they are out there.
Finding Printers with Google
Sometimes for convenience admins will put links to there printers' web interfaces on an Intranet site so they can easily admin them or pull off stored documents. Well, sometimes an Intranet is not really just an Intranet but accessible via the Internet. Google is a great way to find these printers. Here are a few search strings that may be of interest:
Ricoh Savins (Since these printer frequently store documents where to can be downloaded this can be a real killer for security)
intitle:"web image monitor"
HP Jetdirects (Varies greatly from model to model)