Kaizena doesn't support printing files directly.
However, you can open the file in Google Docs, and print from there. Open the file in the conversation, then click here to open the file in Google Docs:
Note that this will only show up if you have permission to view the file in Google Docs. If you don't have permission, ask the owner of the file to give you permission by clicking the blue "Share" button in Google Docs:
You can print the file in Google Docs by clicking "File" then "Print."