Anne - thanks for your suggestion. My Page activity is a single document consisting of screenshots and text; as a Page activity it is scrollable, just like a webpage. I prefer using the Page activity rather than a link to a document, because I don't have to store a document in Moodle for reference, and it is much quicker to have it open in a Page popup than going through the "what do you want to do with this?" dialogue box.
I think you're right, though, that the Page is operating like an HTML page, and only printing the "first" section. How to get it to print the entire thing is my question, I guess.
For example, in the Questionnaire activity, I can print out an entire questionnaire, covering several pages. But the Questionnaire activity has a little "print icon" in the corner.....whereas my Page activity doesn't.