You will need to edit the template. In this case the spTopicView.php template in the /templates folder of your SP theme. Just remove or comment out the function that contains the print code – that is sp_PostIndexPrint().

As always we recommend that you create your own SP theme so that any customisation is not lost during a future update. (http://codex.simple-press.com/codex/themes/theme-basics/creating-a-theme/)