| 摘要 |
PURPOSE:To increase a running speed of a sector, and also to generate no uneven exposure even at the time of a high speed second, by constituting so that preliminary running of the sector is executed by applying a pulse current of prescribed width to an electromagnetic driving source, and after that, the exposure opening part is made to run by inertia energy. CONSTITUTION:When a pulse signal from a controlling circuit 30 is applied to the base of a transistor 21 and 24 by pressing a shutter button, this transistor conducts by its rise, a current (about 1-2A) of the forward direction flows to a coil 14 from an electric power source 29, and the coil is energized for a constant interval of time. As a result, the coil 14 turns quickly clockwise, and the front sector starts running. Until a slit forming edge 2a of the front sector reaches one end of an opening 1a from a stop position shown in the figure, namely, in the course of a preliminary running distance l, the slit forming sector reaches an almost equal speed running state and runs by inertia energy together with the coil 14 after a supply current is reduced by fall of the pulse. |
