Digital BW, The Print

i should have noted in my original post that i never use high speed 
printing and that the problem i am encountering is rather 
intermittent and didn't start until year 2.  Thus is unlikely to be 
something as fundamental as print head alignment.  I have 
encountered both the broad banding in both color and B&W and the 
very fine banding in BO.  I can make it go away with 3 or 4 head 
cleaning cycles.  When working well, the prints are beautiful.