A system for positioning a tarpaulin on a flatbed is provided. The method includes receiving and storing a facsimile at a voicemail system. 2% proof stress of at least a portion the column longitudinal bars is larger than the yield point or the 0. A potential below the first horizontal transfer electrode is higher than a potential below the second horizontal transfer electrode that is arranged adjacent to the first horizontal transfer electrode and backward along a transfer direction with respect to the first horizontal transfer electrode.