Digital BW, The Print

I have an HP 7960 that has been sitting idle for a few years now and 
the cartridges--though still in the packages--are way out of date. 

I'd like to start printing again with this printer, using only b/w 
mode. I read somewhere that in this mode, it only uses the no. 59 
cartridge and I'm wondering if this is true? 

If it is true that this printer uses only the no. 59 cartridge in BW 
printing, than I'll only buy a new one of these, and not all three 
cartridges. 

Best, David