I've suddenly found out, that when I "print" any regular PDF document to a PDF virtual printer, it always converts a source regular (textual) PDF document into an image only document. It applies even to pure plain text documents (say, HTML source code etc.)
(I often need to create a PDF document from the existing PDF. Yes, I know, it might seems quite pointless, but actually it makes sense.)
I've checked many famous virtual PDF printers, as e.g. pdfFactory, Bullzip PDF, qvPDF, doPDF and some others and played a lot with their settings - but the result was always the same, although the quality of image and size of output PDF a bit vary from app to app.
AFAIK all these virtual printers actually use Ghostscript engine to generate an output PDF file, so I suggest, that this is Ghostcript's feature/bug/work specific. Is there any workaround for a virtual printer to generate from a textual document an output regular textual file, not to convert it to an image?