D22-542 is saying that there's a problem with the printed circuit board on the print drum. It's not communicating with the machine. D04 -534 says that the incorrect ink cartridge is installed. First, is this a new drum you are introducing into the machine? if it is, not all drums are interchangeable. You need to get the right pcb (printed circuit board) for the ink drum you are using to match your machine. Second.. Something is mismatched here with the ink cartridges. The only way you'd get the ink cartridge error is if the drum is in the machine. I had this problem with a Rn 2130 ui.. I bought a used drum off e-bay and it wouldn't work. When I stole the pcb from another color drum it worked fine. If you have been using this drum in this machine before... be sure that the connection between the drum and the machine is good. Make sure you have the right ink cartridge too. Some of these aftermarked re-sellers sell stuff that doesn't line up with the tabs on the inside.. I've got some ink here that if you hold your toungue just right and turn the tube about 2 degrees it'l work.

If show ERROR CODE D22-542 means the board in the drum have some problemif show D04-534 means you are using not original ink, but just press restart key is ok.

I had the CODE D04-534 occur on some of the brand new original cartridges and have been puzzled why they did not work. I tryed the following on my Risograph RZ-390UI and it worked:
go into test mode..
turn off machine and turn it back on while holding down the left and right print position arrows.
if the error code shows up.. press the yellow reset button to clear it.. you will then see a number (firmware ver.) press the "C" button on the number pad..
you should then see the display all zeros "0000"
enter 890 and press start.
then when it beep press the "C" again enter 112
when it beeps again press and hold the yellow clear button and the machine will reboot...
HOPE THIS WORKS ON YOURS...