A blow-molded synthetic resin bottle that can be fully flattened and easily restored to an original shape. When an ink tank is mounted on a head cartridge, a hook of a set lever is obstructed to be operated in a lock releasing direction by a restricting surface of the ink tank. Lower portions of the side walls are formed into bag arms that secure the plastic handles formed in the plastic bag. Additionally, a shutter, triggered by a signal from the first sensor component, allows radiation from the radiation source to pass through the scanning zone in the direction of the radiation detector when the second portion of the moving target is passing through the scanning zone and closes off the radiation when the second portion of the moving target is no longer within the scanning zone. The second shading arrangement includes a second hanging system suspendedly support a predetermined set of the slats, so that by lifting up the second hanging system, the predetermined set of the slats are capable of being lifted for selectively allowing a light of desirable intensity passing through. The optical fiber unit transmits the converged light to the photoelectric unit.