The present invention provides an ink set for ink jet recording comprising: an ink which contains: water; a colorant; a water-soluble organic solvent; polyvalent metal ions; and compound which is intrinsically capable of substantially inactivating the polyvalent metal ions, and a liquid composition is of a pH in which the polyvalent metal ions in the ink can be substantially activated. The conductive lines exhibit different widths selected according to the desired impedance ratio of the transformer. A current sensor coupled to the first inductor can provide a first signal indicative of the current flowing through the first inductor, regardless of whether the switch is on or off. A mirror assembly is coupled to a distal end of the elongated tubular member.