These printers use the TK-8307K cartridge:
Click On a Printer to View it's Cartridges
          Kyocera-Mita TASKalfa 3050 CI
          Kyocera-Mita TASKalfa 3051 CI
          Kyocera-Mita TASKalfa 3550 CI
          Kyocera-Mita TASKalfa 3551 CI
          Royal-Copystar 3050 CI
          Royal-Copystar 3051 CI
          Royal-Copystar 3550 CI
          Royal-Copystar 3551 CI