For the ink jet printers, beware that when they clean
their print heads,
some models dump the excess ink into this foam or into something like
blotting paper. The older and larger models have an excess ink bottle,
and after many many hours operation they will ask you to empty that
bottle. Usually this is based on a calculation of how much ink is there,
rather than a level sensor, so if you tell the printer you have emptied
it, but haven't actually done it, it will eventually overflow and make a
real mess of you carpet. Some small printers so the same calculation of
when the foam/blotting paper is fully saturated and ask you to change it.
Xerox were champions on that problems. Field Technicians used a syringe
and a needle to empty spent ink tanks!