If you use only plain text (no HTML formatting, no cropping), you can try to set the "Text Rendering Policy" on tab "PDF" in the PDF Export settings to "Plain Text".
Please note, due to the text rendering behavior of the Java platform (over which we cannot control), plain text embedding cannot be guaranteed.
Another possibility would be exporting to SVG and use a vector drawing application like Inkscape to convert the exported SVG document to PDF.
