Digital BW, The Print

The piezo driver "drives" the Epson stepper motor in finer increments as the Epson driver does. For printers that are manufactured within perfect tolerances, this results in 
virtually dot free prints. For printers on the edges of the tolerance scale, with weak drive mechanisms, you will be plagued by banding. Using the The Epson driver, that one 
rarely bands, but some people notice the Epson dither. Its all a matter of taste. Try the 20"test-print an image excatly 20" and measure the output- If it's off by more than 1/8" 
(.125"), you printer was made off  tolerance, has a weak drive mechanism and if used with the fine drive demands of the piezo driver, it may band. If you have a smaller printer, 
print a 18" image and the range of acceptability is .9 of 1/8" (.1125") 

John Luke