Photosmart C4680 Blurry printing of pdfs, emails and web pages

Hello, 

I posted this yesterday in the Mac-only forum, and am re-posting here in the hope of a quicker response, given the holiday weekend.

My Photosmart C4680 has only recently begun printing blurry pdfs, emails and web pages, which are not blurry because of ink problems, but look as if they were printed during a mild earthquake.   Printing of Word and Text Edit documents

from my computer is fine.  I've done the troubleshooting and re-scanned the alignment page--no change.

I have a Mac, running OS X 10.6.8.

Thanks in advance for your help!