These printers use the UX50ND cartridge:

Sharp Fax FO-4500

Sharp Fax FO-4550

Sharp Fax FO-5500

Sharp Fax FO-5600

Sharp Fax FO-6500

Sharp Fax UX-5000

Sharp FO 4500

Sharp FO 5500

Sharp FO 5600

Sharp FO 6500

Sharp FO 6550

Sharp FO 6600

Sharp FO 6650

Sharp FO 7500

Sharp UX 5000

Sharp UX 5000 Pro

Sharp UX 5000 Pro Laser