Reader DC printing PDFs with an unwanted gray background

I have 2 Win7 Pro computers, 1 with Acrobat Pro, the other with Reader DC, both updated to latest versions.

When I print a PDF with Reader, the page is printed with a dark gray background, making the text unreadable. If I print the same document, to the same printer with Pro, the PDF prints normally. I have tried "print as image", but then tables and some parts of the document are still printing with a gray background. I have also tried several different documents, all with the same result.