Проблемы с принтером GPO

One one of the computers where the printers are not installed, run the following:

gpresult /h gpresult.html  

From the user's logon context.

This will show the user's group memberships, and the GPO's applied/denied. This will help you narrow down if it is an issue with group membership not being picked up, or if the GPO's aren't being processed, or if the computer does not even report on the GPO.