A system for controlling a battery to extend a driving mileage is provided. The instrument can further comprise a drive member and the articulation joint can comprise flexible support members which can be configured to support the drive member. The captured subject image can be displayed on the display, according to the features of an interested area image. A developing bias voltage is applied to the conveyor when the two-level developing operation is performed and developing conditions are established such that an amount of the developer that is moved to and adheres to the latent image bearing member image area is saturated.