There are no add-ons so that explains why you cannot find them.
The only way to do what you want is via a PDF or a number of PDFs.
The information would have to be downloaded somehow to get it to the printer so in reality there would be a download.
I suggest a page that lists the sections of the help plus an All option.
You might also like to ask your management if they would be happy if everyone in your office downloaded and printed the help from say Word? No doubt the local paper supplier would.
See www.grainge.org for RoboHelp and Authoring tips
You might think about providing an additional HTML Help version (.chm file), which I believe still allows you to print "books" from the TOC. You could create a custom layout for this output, which would require no post-production work (pagination, etc.) such as with the Word/PDF method. However, a download would still be required.