Abstract: Disclosed is a cartridge having an encoder wheel thereon for encoding EP supply cartridge characteristic information for an electrophotographic machine, the cartridge comprising, a sump for carrying an initial amount of toner. A shaft is mounted for rotation in said sump, and an agitator or paddle is mounted thereon in such a manner that when the shaft rotates, the paddle rotates into, through and out of engagement with toner carried by the sump. A single encoder wheel is mounted on the shaft, external of the sump, the encoder wheel positioned for proximate mating coaction with a coded wheel reader when the cartridge is mounted in position in the electrophotographic machine. A drive means, and a variable torque flexible coupling connects the drive means to the shaft to effect rotation thereof.