Hello killadark,
I understand your frustration and see you have just recently put in new ink cartridges. I am sure you have done all the troubleshooting you would like to do, but I do have one more recommendation. Your HP Officejet 6500 Plus has a removeableprinthead, I believe you just need a good cleaning and to flush the printhead. This is my suggestion not that of HP's. I have used this many times and have had great feedback and results from other Community members with the same print quality issues.
Please take a look at the video below:
I hope this helps!
Thanks,