Black and white printer

[drew2143]

Hey guys,
A friend of mine was telling me about black and white printers that use 8 different tones of black. Instead of having 8 color cartridges, they have 8 black cartridges. Does anyone know what these are called? Supposedly the prints are close to black and white analog print quality.
thanks

[deckcadet]

I don't know if there are dedicated printers like this, but some companies make a set of 8 ink cartridges for black and whites for the Epson R2400 and similar large inkjet printers that use 8 colors. I think one of the companies may be called something like Piezography?