Below is some interesting information
about ink cartridges in general
(their longevity)
Inks are water solutions and cartridges
are made of what seems to be
polyethylene. Over a period of years,
water molecules will migrate through
the walls of the cartridge--
it has nothing to do with whether
the cartridge is sealed properly or not
it will happen anyway.
This situation is roughly analogous to
a balloon filled with air.
After several days,
air leaks through the rubber,
no matter how well it is sealed.
The bottom line is that cartridges
have a shelf-life on the order of years.
They should be fine for about 3 years
or so at room temperature.
They can last much longer at
lower temperatures, but don't allow
them to freeze--the water will expand
and possibly break the cartridge.
In theory, a way to make cartridges
last *almost* indefinitely, would be to
store them in a jar filled with water.
This would *essentially* keep the
water inside the cartridge in equilibrium with
the water outside--i.e.
about as much water would leak in
as would leak out.
The reason that I said *almost* is
that there is a very weak force of
osmosis at work.
This is because there is a difference
in the concentration of molecules
dissolved inside the cartridge
(i.e. the ink and small amounts of other
additives) and outside,
where there is nothing dissolved).
This force will very slowly pull water
into the cartridge as the exact
concentrations attempt to reach
equilibrium
(this is the principal of dialysis).
However, we are now talking about
a process that would take perhaps
decades.
Also in theory, if the water in the bottle
had the exact concentration of large
molecules as inside the cartridge,
the cartridge would last more than a
lifetime.