Can't print from Notepad++

[CableWombat]

I have no idea what went wrong but on my system it’s no longer possible to print from NP++.
All other programs can print without problems; only with NP++ the following happens:

When I try to print e.g. a text of three pages, the printer gives me three pages but all of them are blank.
I tried to print to PDF, same here: I get a PDF-file with three blank pages. It’s like the printing works but with invisible text.

Any idea how I can find the culprit?

[CableWombat]

Found it just minutes after posting: Settings > Preferences > Print. The Colour option had to be changed from “WYSIWYG” to “Black on white”.