The Printing Press certainly DID NOT cause the Reformation.

It certainly helped it along though.
Bulk printing copies instead of hand writing them out helped distribute documents 1000 times quicker than before. Which means a 1000 more people would get to read them.
It also meant that anyone with a printing press could PRINT just about anything out without the "blessings" or without the directions of the leaders, the Pope, or the Church.
Whereas pretty much the only people that were processing any kind of documents before the printing press was one of the above three.... the leaders, the Pope, and the Church.

Free Press!