These printers use the FO50ND cartridge:

Sharp FO 550

Sharp FO 4400

Sharp FO 4450

Sharp FO 4470

Sharp FO 4650

Sharp FO 4700

Sharp FO 4970

Sharp FO 5550

Sharp FO 5700

Sharp FO 5800

Sharp FO 5900

Sharp FO 6700

Sharp FO DC-500

Sharp FO DC-525

Sharp FO DC-535

Sharp FO DC-600

Sharp FO DC-635