Digital BW, The Print

Since some of the posts lately have been discussing getting control of
all the inks in the 8 ink printers and I've been finding that two
passes makes for much darker K in an image, I wonder if you RIP
programmers have any idea if you can make an Epson  stop before
ejecting a sheet and wind it back in for a second pass? I know the
printer can pull the paper back, it does so briefly when the paper
loads, but is that another function that's hidden in firm- or hardware?

I've done multi-pass printing for a number or reasons in the past
(even using two different printers), but always found that I could do
 similar things  more easily in one pass. Now I have a better reason
for working on multi-pass techniques - increased K. 

I find that, my 1160 will register horizontally pretty well, a one
pixel vertical line overprinted in two passes shows no separation, but
a horizontal line (for vertcal registration) is off 2 pixels - that's
due to variance in paper loading. If I didn't have to reload the
paper, but it could simply be rewound by the printer, vertical
registration might be taken care of - thus my question to you
programmers, above.

As for the technique of image handling for double printing, that
remains to be worked out, but my initial tests of making a duplicate
layer with only some of the darkest tones, feathered and printed over
the first full image looks good enough to make the pursuit seem
worthwhile in the absence of a single pass method to get increased K.

Thanks for any help,

Frank