Agreed, I ran several busy printers for a large department. The ljet IIIs were work houses and ran nearly forever if you used the recommended part replacement

Agreed, I ran several busy printers for a large department. The ljet IIIs were work houses and ran nearly forever if you used the recommended part replacement schedule. We had a ljet III that outlasted ljet 4, ljet 5, and ljet 4000. Ljet 3 was the last with the HP print engine, afterwards they used Canon print engines. The network interface was brittle, even a nmap would hang the printer. So we firewalled it off and used CUPS to handle postscript -> PCL. Sending only PCL to the printer (postscript memory and CPU is unbounded) made them faster and MUCH more reliable.