I found a way to fix my printerhead that was not in the community.....it really worked!!!
Product: officejet pro 8720
II am here to say that after spending time looking for a solution to my printer head failure, (on my 2 year-old HP Officejet Pro 8720 printer, scanner Fax & copy) I was ready to give it up. HP had info, you tube had videos & nothing worked. In desperation, feeling there was nothing to lose, I removed the ink cartridges, lifted the arm lock on the printer head, removed that & then took my hurricane air gun to the inside of the printer to remove any dust, air blasted the inside & outside of the printer head, air blasted the ink cartridges, replace the printer head into the interior, locked it back in, added the cartridges and VIOLA!!!!!!The printer came back to life. I went to settings &did the maintenance work recommened. All is well with my printer. Just thought that HP is not getting the solution to the problem by suggesting going to "Maintenance setting" since you cannot get there when your printer head is "lost, damaged, etc." I was ready to quit HP forever.....They need to come up with better solutions. as I found, because good PR is lost when we find no solutions --I just got lucky because I am persistent. I hope this solution can be added to your community forum, HP.