[gchappel]

These cartridges are still available- easiest.
I do not have any experience with this model printer/plotter. I have refilled cartridges on photo printers for years, epson, canon, hp. Just drill a hole (in the right spot), fill with the correct type of ink, plug hole with a little rubber stopper. Easy. Goggle is your friend.
If google does not help you- you can disassemble a cartridge to see its layout and figure out where the ink needs to go. Getting the correct ink is important- pigment vs dye, etc.
The one hoop you may need to jump through- in some printers if a cartridge is read as empty by the printer- the printer will not print with it even if you refill it. You then need to reset the chip in the cartridge. I have chip resetters for several printers. One way around this-- refill the cartridge before the printer says it is empty. Then the chip never comes into play.
For occasional use it is a mess and not worth it- just buy the $50 cartridges. I at times go through 100ml of ink in a day. Then refilling is worth it.
gary