Embodiments described herein involve configuring a playback device based on the detection of a barrier in proximity to the playback device. The DMD is provided with a light shielding cover having a light transmitting portion which corresponds to the element face. The paste should preferably contain from 30 to 95 wt. The control unit continues the image erasing process until a value obtained by counting the number of the recording mediums conveyed to the erasing unit by including the number of the recording mediums causing a conveyance error reaches the setting number when resuming the image erasing process after stopping the image erasing process in the event of the conveyance error of the recording medium. A Schottky gate opening is formed within a step gate opening to create a step gate structure.