How to Print/Export the schema builder?

Print/export from Schema Builder is not currently possible, but you can go vote on the idea for a future release.

There is, however, ERD Tool, a free app in the AppExchange that might work for you.

One of my first jobs was to print out the schema for the org i took over.

The only way I got the schema builder to "print" was to take screenshots and then place them together in MS Pain or Photoshop.

It looked so horrible I ditched it.

There is a tool out there called SchemaSpy that was able to give me printable ER Diagrams: http://blog.jeffdouglas.com/2010/05/12/running-the-force-metadata-jdbc-driver-for-schemaspy/

There is a product called Safyr that extracts metadata from SFDC and among other things, allows tables to be visualized as e-r diagrams, both within the product itself, and in a bunch of data modelling tools like ERwin, ER/Studio and PowerDesigner. You can also use Visio, as long as its 2010 or earlier (they took the data modelling capability out of Visio from 2013)