Strange, my printers heads kept drying out and I was told (here’s the thread) that adding a humidifier in the room that has the printer will work in preventing this problem. I did as it was recommended, and higher RH improved this situation. But I suppose it only make sense in a very dry climate (as we live in a desert).
I try to keep my humidity between 40 & 50%, been using an Epson printers for many years with no problems (4000, 9800 and now a 9900 for close to 2-years). Just be sure to get a humidifier with in-built sensor (mine is Levoit) to keep it under control, and everything would be just fine.