I suggest that you experiment with a few different PDF printer drivers to see if you get different results or that you tweak your DOCX file so that the conversion to PDF is more accurate. Both of those options would be better than a DOCX to Image to PDF conversion.
As for your request, you have a couple of options:
- Manually take a screenshot of each page in your DOCX file
- Use a DOCX to Image conversion tool or service (Google it)
- Convert the image to PDF
However, it's likely that any DOCX to Image conversion tool is actually going to go through the same rendering process that the DOCX file goes through when being printed to PDF as the mechanics of printing to an image virtual printer and a PDF virtual printer are very similar.
So that really leaves you with the first option of taking a screenshot of each page manually -- unlikely to find a command line tool that does this as it is a little unusual -- or get the DOCX file into shape so that printing to PDF gives you the results you want.