The LaserJet 4 series were discontinued in the 90’s, with their replacement being the LaserJet 5, which was discontinued a handful of years later; it was the last of the Canon EX/EX+ based LaserJet printers. the 4000 series took over from it, and I imagine there’s still a few still in use.
Keep in mind that these are laser printers and not inkjets, and they are aimed at business and not consumer.