blurry text / clear photos - what is going on?

When printing from Word or forms downloaded from Chrome of Safari we get blurry text in places. This is a Canon MG7150 printer. We are printing from MB Pros running OS10.11.06

Sometimes the text is sharp and sometimes it is blurry, it goes line by line. Maybe 50% of a doc will be blurry and 50% clear. The photos or JPGs we print are fine. If I use Snipping Tool to copy a text document and print that then it wil clear which pretty much rules out anything w/ the printer. I have cleaned the encoder film anyway and nothing changed. I've also checked the nozzles by printing the test sheet and that is clear. 

The problem sounds exactly like what this guy was experiencing with an MX922

http://community.usa.canon.com/t5/Printer-Multifunction-Support/MX922-Blurry-Text-Black-only/m-p/164203/highlight/true#M14115

It seems related to text or font. Can anybody offer any advice? 

Thanks