During thermal recording and optical fixing of a sheet of thermosensitive recording paper, a leading end of the recording paper has been clamped by a clamp member for securing the recording paper to a platen drum. Thereafter, the clamp member is released, and the platen drum is rotated at a high speed to rapidly move the leading end to a bleaching position directly below the center of an ultraviolet lamp which is used for the optical fixing. The leading end is stopped in the bleaching position for a short time enough to bleach the leading end by the ultraviolet rays.