This invention provides an Mg-based ferrite carrier composed of an environment-friendly material meeting environmental regulations, and an electrophotographic developer comprising the carrier. The plate is pivotally connected to an end of the body and the retaining member is connected to the other end of the body by screws. A log record is created for a first failure log based on the failure type, and storied in a log record storage. Smoothing of data transmission is provided using a time-weighted buffer. In a multi-power semiconductor integrated circuit device, current consumption at the time of power-up is reduced. Immediately before the transition from the first state to the second state, the injection data is altered so that the emissions, in particular the production of noise, are gradually made to approximate the emissions in the second state.