Digital BW, The Print

I am just new in this group, and I see that everybody have great 
knowledge about b&w digital printing, so I think there will be 
someone who could advise me. I scan my films by a Powerlook III Umax 
and Binuscan Photoperfect, then I print them by an Epson 5000 and 
Power RIP 2000 software (with Photoshop 6): normally I am quite 
satisfied of the results in color . The trouble begins with the b&w 
printing: if I print only with black the result is poor, if I print 
monochrome the result is almost "green", regardless the type of 
paper; I have tried duotone method, and I obtain just 2 tones on the 
print...The best result actually is this:I scan b&w negative in mode 
CMYK (Binuscan do this), so I have on my monitor a b&w image but 
CMYK, than I print it in color (power RIP). The print made in this 
way is less "green" and more gray, but it is quite "flat". Before to 
buy another printer b&w dedicated, with black and gray inks, I would 
like to explore all the possibilities of the six color cartridges. Is 
someone of you passed in this situation? Many thanks of your help. 
Daniele Martini.