An object of the present invention is to provide a black ink composition by which a recorded matter in which a fine surface defect on a recorded matter is effectively suppressed, can be obtained. The bar assembly is pivotably connected to a first side portion of the main part for rotation between a first position in which the bar assembly is not in contact a second side portion of the main part and a second position in which the bar notch receives the second side portion. Therefore, the polar transmitter is applicable to the wideband communications, the multi-mode, and the multi-band. In the present invention, cladding boundary geometry structures that can prevent the formation of local modes are disclosed. The reinforcement member is preferably made of plastic, and more preferably made of rigid plastic. A device for coupling the motor to the movable member may be a lead screw mechanism and a pulley system interconnecting the movable member with the stationary or fixed container.