InfoPath Dev

Currently we are using IP 2010 to create a form that is printed after completion.  In the future, we will be integrating with SharePoint once it is implemented throughout our organization.  Having said that, the users completing our form has many "Cannot Be Blank" fields and a couple of fields that must equal 100 or the form is invalid.  Any suggestions on how I can validate these fields before the users print?  I was thinking a button but couldn't figure it out.  Thank you for any suggestions.

Your description implies that when the form is 'complete' then it is printed. But if it is completed, why would there still be fields showing as Cannot be Blank (or any other validation fail indicator)?

So the question is, are these fields showing as 'Cannot be Blank' - do they actually have to be filled in for the form to be 'complete/valid'?