I don;t use Lexmark printers. In general I find their inkjet products
are not very robust, and their ink cartridges are very costly.
To my knowledge Lexmark uses a thermal ink head which is incorporated
into the disposable cartridge. I am unfamiliar with the number 31. In
general I believe Lexmark uses two cartridges, one ganged with 3 or more
colors (CMY and sometimes CcMmY inks).
There may be some instructions on line (perhaps offered by some of the
3rd party ink companies) on how to refill the Lexmark cartridges
properly. You should probably look around and see what 3rd party ink
companies are offering.
The heads do dry out if left in the open air. I suggest you store the
cartridge in a sealed plastic bag to which you have added a small piece
of damp sponge. Just damp enough to keep a but of moisture i there.
This will help the ink still within the cartridge and head from drying
out.Try to keep the cartridge with the head portion up so it doesn't
start leaking ink over itself and everything else. I think all Lexmark
inks are dye based as opposed to pigment, meaning the inks will dissolve
more easily with water even when dried out.
Refilling cartridges can be somewhat messy and a bit tricky, and you may
wish to consider having someone else do it for you, and you may select
to have the cartridge refilled by some dealers. They usually charge
less (about half of that cartridge new).
Art
If you are interested in issues surrounding e-waste,
I invite you to enter the discussion at my blog:
http://e-trashtalk.spaces.live.com/