Good afternoon Katherine,
I will create a feature request to add comments to the print functionality but unfortunately I will not be able to provide you with when this will be available in the platform. Currently the only option using the pre-existing settings would be to print just the blog without the comments. A work around I was able to find using Chrome is as follows:
1) Highlight all of the text you would like printed, including the comments hit Ctrl+P
2) On the print page that comes up click on the link at the bottom:
3) In the popup that appears you will see "Selection" in the "Page Range" area that will allow you to print anything that you have selected.
If you have a PDF writer you should be able to select that software as the a printer to generate a PDF.