Its possible the preconfigured settings are optimizing for file size, not quality. Generally PDF printers allow you to modify the defaults. (You may not be able to do this from the print dialog.) It may be possible to change the compression level to improve the quality.
Go to Bullzip Printer Options (see their knowlege base http://www.bullzip.com/kb/ and scroll down to the info on Options).
EDIT Just want to add if you render to an uncompressed format or lossless compression first like PNG, you may also significantly improve the quality. Especially now with cheap storage and fast internet, there are only a few situations where using jpg is preferable.