A method includes setting a mode of operation of a buffer circuit outputting an output signal. An apparatus and system may include a processor and a storage device that can be encoded with computer-readable instructions, wherein the instructions when read and executed by the processor may include activities such as separating modes in a plurality of coherent time-domain signals, and recombining the modes in a frequency domain. This structure, free of line discontinuity which lowers the Q value, can provide a resonator having a high Q value equivalent to that of the one-wavelength resonator. The motor has a gear case which is integrally formed with a reduction mechanism accommodating portion to accommodate a reduction mechanism and with a brush holder mounting portion in which the brush holders can be installed in a direction of an axis of the output shaft. The alignment structure may be formed form a ring-shaped structure with an opening. The first writing control device is configured to start a writing process of the first latent image based on one of the signal of the criterion timing or the signal of the writing instruction received from the criterion timing determination device, and to transmit a signal of a timing for starting a writing process to the second writing control device.