OSX 10.11 El Capitan

I'm looking for a printer driver for my HP Officejet Pro K550, which has been a really reliable printer, but can't find one. I would prefer not to have to replace it, as there's nothing wrong with it, and I really like it. Apple don't do one for it, and I can't see that HP has one either. Seems they want people to buy new printers, which seems a travesty, when this one is perfectly serviceable.