An ink cartridge includes a flexible container containing ink; and a restriction mechanism allowing the flexible container to deform only in the direction to decrease the volume of the flexible container. When the sun gear is rotated, the nut members perform planetary motion inside the internal tooth gear, by which the screw shafts are reciprocally moved in axial directions thereof. Following that, the thread plug is unravelled in an unravelling area on the circumference of the processing drum into the crimped thread which is pulled of the processing drum. The hydrate fibers can transform to oxide fiber after calcination at high temperature. A pair of first step surfaces are arranged at opposite end portions of the lifter, respectively, and the second step surface is arranged between the first step surfaces at a level lower than that of the first step surfaces. The cladding regions have a low Al mole fraction, so that they have a direct bandgap.