A method and apparatus for low cost upgrading on demand of an optical fiber communication system without installing additional optical fiber and minimal installation of optical circuitry at destination and distribution terminals. The inductance andor the magnetic coupling of a plurality of coils or windings of the inductor can be precisely set through the ferromagnetic material, which is inside an insulant window that is fixed to the carrier, being deposited on the carrier during the coating process. The toner crushing member is provided in association with the screw and configured to crush toner accumulated between the screw and the blade, by being swung by the screw rotating.