Are you a psychic?

Then no, I'm sorry, but you don't know that those prints are yours.  There are forty-some other computers hooked up to the same printer as yours, and most of them are occupied.  While most people don't print anything, there are, say, one out of every four people that do print.

Which makes it unlikely that you know that those prints are yours.  As in impossible for them to belong to anyone else.

Please, sir.  And no, I won't leave fingerprints on them.  Not visible ones, at least.  I touch the edges of the pages, not the center.  And I haven't been playing with graphite.  So, no, no visible prints from this librarian.