THIS is very strange because this same thing happens to one of our smart tank printers at work (a 650 series), and ONLY slamming the printer carriage access door shut fixes it!!
When I first got the error I thought my BRAND NEW printer heads were damaged, so I just ordered another set, at $70 freaking dollars, Well, they worked about a month before it started happening again.
So I was telling a guy at work and he said "Did you try slamming the print head/carriage door shut?" I told him I hadn't tried that yet but didn't think that was the solution.... BUT IT WAS!!
I went home that night and tried taking the heads out and reinserting them, and was about to call HP and get a refund and got mad, and lightly slammed the top down....AND IT WORKED!! The error went away and the printer printed the documents I NEEDED!
However, after a period of sitting (or not being used a lot) the printer does it again, and again firmly closing the carriage access door solves it for a while.
Does anyone have any idea WHY this happens? Why does the printer falsely claim that the printer heads are bad when they aren't, and then work again after smacking it around like an old Ford truck? The guy at work claims he's been doing this for 3 years now.....