There are two basic ways of having a relatively "fixed" image from an
inkjet printer, one is based upon the ink technology and the other on
the paper.
If your printer is using dye colorant inks, as your HP does, then you
need a paper which uses microporous technology. This paper has a
semi-permeable membrane on the surface that allows the ink to penetrate
it, but the ink is then trapped in a kaolin clay surface underneath that
locks the colorants in. The paper then basically becomes "waterproof"
Epson makes such papers (in both matte and glossy finish), as do many
other manufacturers.
Most of HP's inkjet papers, which do have a higher fade resistance when
dye colorants are used, is called swellable polymer, and this paper's
surface is water soluble. It works by having the ink wet the paper, and
then the ink is reintegrated into the surface polymer, which tangles the
ink color into the long chain polymer molecules to keep them from being
re-energized by environmental conditions like UV light and certain
reducing agents like ozone. The problem with this system is that the
paper coating remains water soluble.
The second approach is to use a printer which works with pigment
colorant inks. These inks use non-soluble particles suspended in a
fluid, which usually contains a resin to both adhere them to the paper
surface and to coat them to make the surface smoother and more evenly
glossy.
The main supplier of pigment color ink printers today is Epson, although
Canon makes a few, as well.
Any of Epson's printers which use Durabrite, Durabrite Ultra,
Ultrachrome or Ultrachrome Glossy inks use these waterproof pigment
colorant.
The least expensive of these printers are the 4 color Durabrite or
Durabrite Ultra ink printers (they only make them in 4 color versions)
which include the C, single function, or CX and DX models All-in-One models.
Both the Ultrachrome and Durabrite inkset are waterproof when dry (the
Durabrite sets dry faster, but also clog faster with lack of use), and
both have very long fade resistance, extending to several hundred years
under glass.
Art
PS: If you are expecting there to be no damage at all to a print when
you spill coffee on it, I'm afraid the only answer for that is to
laminate it in plastic on both sides... then you can literally wash it off.
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/