Digital BW, The Print

As a newcomer to digital B&W I was encouraged to see a note in this
forum by Paul Roark (#71625) that the Epson R220 can handle (presumably
MIS) variable-tone inks.  In my search for a dedicated printer this
causes me to rank the 220 above the 1280, which seemed to have a
greater range of operation but has gotten some bad press here for its
tendency to clog.

Where, though, is there a description of the usage of variable-tone inks
in the R220?  Or is that all really in the experimental stage?  I would
like to jump to variable-tone printing without investing in monotone, if
that is feasible (inks, I see, are not cheap), and have an interest and
experience on the computer side and enjoy a technical challenge, though
B&W is a new game for me.

I would be grateful for any comments.

Frank