I don't believe that is necessarily true.
For the last three days I have been dissecting and investigating the
Epson individual color ink cartridges used for the Durabrite and
Ultrachrome inks. I've now taken about siz apart to differing stages
because I am working on figuring out both how they work and how it might
be possible to do a proper refill with them.
Unlike the larger sponge/batting cartridges, these have none of that.
They are basically a series of chambers and valves. There is not
anything, other than one small foam filter that appears to be even
slightly used up during use, other than the ink itself. If a proper
refilling method could be developed, I could see these cartridges being
reused many times over as long as reasonable standards of care are taken.
Art