Oh, glad that you got it working.
If the problem returns, it could be the toner.
Thank you for your detailed explanation. I had a "Eureka" moment and created a large rectange in WORD and filled it with BLACK. I ran through ten or so sheets of paper and the printer returned to its normal black.
This is what I could find::
Can any get me out of this dilemma. It has happened before and rectified itself. I am using genuine cartridges.
My first posting, Thank you.