Abstract: To realize a battery state monitoring circuit in which detection is reliably made even if a continuous noise is entered, and to provide a battery device which has a long life and is safe. In the battery state monitoring circuit, the detecting circuit outputs a signal for controlling a switch circuit in accordance with a state of the secondary battery with respect to one of a specified voltage value and a specified current value. The signal includes one of: a detection signal for starting one of charge protection and discharge protection of the secondary battery; and a release signal for releasing the one of the charge protection and the discharge protection of the secondary battery. A switching rate from the release signal to the detection signal is higher than a switching rate from the detection signal to the release signal.

Abstract: A polygon scanner motor has a polygon mirror having an outer periphery, a mirror surface for scanning light arranged around the outer periphery, and a setting hole having an inner periphery. A rotor has a projection having a plastically deformable edge portion. The polygon mirror is positioned relative to the rotor so that the edge portion of the projection is disposed opposite a surface portion of the inner periphery of the setting hole proximate a center of the inner periphery in the axial direction thereof. The edge portion of the projection is plastically deformed against the surface portion of the inner periphery of the setting hole to thereby connect the polygon mirror to the rotor.