When recording a signal to a magnetic tape 12 serving as a recording medium, recording information 36 including the start time and the end time of recording and the recording source is stored to storage means 6 other than the above tape 12. The ratio of the amount of the recovered toner to be supplied into the developing device to the amount of new toner is arbitrarily increased or reduced. Upon detection, mobile devices add their respective selected notifications to the prioritized list. Also included is a method for reducing the stress within the light engine. In executing a WRITE command, a data request packet is transmitted from the transmission buffer.