A method for identifying faults contributing to a data transfer error in a tape drive. The mail pieces can be subsequently placed in a tray and a label is applied to the tray, the label imprinted with information which relates to the mail piece content of the tray. The method may also include selecting, from the plurality of window sets, the window set having the window corresponding to a lowest total inventory management cost. With this operation, the substrate stage can be driven without difficulty even when the substrate stage and the empty-weight canceling mechanism are configured of separate bodies. regardless of whether the constituting resin is a thermosetting resin or a thermoplastic resin is provided.