There is provided a signal processing device for remedying an error in reading bar-codes derived from a defect of the bar-code printed on a label, a way to hold the bar-code reader’s sensor to the bar-code and so forth. The washing machine comprises a cabinet having a door mounted thereon, a water tub installed inside the cabinet, a washing tub installed inside the water tub; and a venting unit installed such that an outside of the cabinet is in communication with an inner space of the washing tub through the venting unit. The fan housing contains a fan the draws air from the building through the duct. Alternatively, the magnetic receiver may employ, as the feedback device, a current feedback amplifier circuit to cancel the inducing field inside the core. Optionally, permanent sterilization s effected by passing a current through there resilient structure to the tubal walls.