As long as you use a true type font, the printer should recognize that font and be able to "read" the text in it. Only old bitmap fonts are fonts that might be not readable by the printer. Usually commonly used TT fonts on windows like "Courier New" or "Times New Roman", are already in the printer so they won't even be downloaded.
However, RightFax does have some documentation on escape codes here, so you might want to try using escape codes with ActiveReports. Also, here is an example of using the SystemPrinter object in ActiveReports6 to send escape codes directly to the printer without using any special API. You might try using that code and replacing the escape code there with ones that RightFax understands.
Finally, ActiveReports essentially prints by getting a graphics from the printer and drawing on it. Textboxes are real text drawn with appropriate text commands (i.e. text is not rendered as bitmaps). This is a normal way of printing in modern windows so any printer should see the text as normal text. You should be abel to see the same exact results by writing your own simple printing code in .NET and sending it to the RightFax driver. If it works there it will work in ActiveReports.
If it isn't working, and the escape code trick above won't work, I think contacting RightFax and asking them for insight into how to print to their driver from a .NET application would be the next logical step.
Hope this helps!