I wish I had read all of these complaints before I bought my Officejet Pro 6830 in 2015. It worked well for about six months before I left the country for a year. When I returned in late 2017 it worked ok for a month or so before I began receiveing the "Problem with printhead" notifications. It became clear that the machine was never going to work again and that all HP was going to do was to offer to sell me a refurbished priniter of the same kind which would probably break down with the same problem in a few months. This is the third HP Printer I have owned in the past 5 years but I am finally awake now and will move away from HP's (which I have always bought in the past) and start looking at other brands as it is clear that HP's are not the reliable machines they used to be nor is HP Customer Service as good as it used to be.
Yindee