Copying, dubbing or reproducing copyrighted digital data can be inhibited or restricted to properly protect a copyright. According to a first embodiment variation of the method according to the present invention, for example, in the course of detecting raw measured values of the air resistance coefficient of the model, the effective diameter of the suspension wires is reduced in at least three steps by removing sleeves which have been pushed on. An air passage in the outlet entrains ambient air in water passing through the outlet. The base is received in the groove and defines two first receiving grooves. This suppresses the amount of the ink consumed in maintenance of the printer.