This could be the web browser you are using. If you are using "Internet Explorer", the print settings are smaller and sometimes preset print setting will obscure the tax return printing. Unfortunately this cannot be fixed.
If you are using "Firefox", the print settings also cause problems.
If you use "Chrome" then the print setting will be excellent.
Completed tax return print the best when you use "Chrome" to complete the return.
So try to print your tax return through "Chrome".
Also please note the pop-up message when printing a return, which confirms the above.