There are a variety of reasons why a printer might start printing blank pages. Have a look here and you'll be back to printing as usual in no time.

What Causes a Printer to Print Blank Copies?. Running a profitable business takes careful cost containment. When you examine a printed presentation, reference document or other business content ...

For example, if you set up a four-page project in 2-Up Perfect Bound format and use an 8-page signature, InDesign adds four blank pages to fill out the signature.