In an optical disk apparatus having an exclusive RF detector plane mounted therefore, as a method of obtaining a synthesized readout signal based on band-synthesis is used in order to obtain a readout signal having a good SN ratio, a waveform distortion easily caused by a delay time difference or a sensitivity difference in the playback at higher speeds can be prevented. The user equipment comprises circuitry configured to process a user equipment identification by \xbd rate convolutionally encoding the UE ID to produce a code. Besides calcium carbonate, the composition of blending agents can comprise calcium hydrogen carbonate and meta-kaolin sinter, too. A first one of the inks contains Direct Blue 199 as a primary or exclusive dye, a second one of the inks contains Reactive Red 180 as a primary or exclusive dye, and a third one of the inks contains Reactive Yellow 37 as a primary or exclusive dye.