Abstract: A light sensor generates a detection signal upon receiving laser light. A rotation sensor generates a rotation signal in synchronization with rotation of a polygon motor. A mirror-rotation-signal generating section generates a mirror rotation signal, based on the detection signal. A motor-rotation-signal generating section generates a motor rotation signal, based on the rotation signal. A phase-difference measuring section measures a phase difference between the motor rotation signal and the mirror rotation signal. A prediction-signal generating section generates a prediction signal that is delayed from the motor rotation signal by the phase difference. A switching section switches a control mode between: a mirror control mode in which the mirror rotation signal is used to control a rotational speed of the polygon mirror; and a prediction control mode in which the prediction signal is used to control the rotational speed. A motor driver drives the polygon motor in the selected control mode.

Abstract: A light sensor generates a detection signal upon receiving laser light. A rotation sensor generates a rotation signal in synchronization with rotation of a polygon motor. A mirror-rotation-signal generating section generates a mirror rotation signal, based on the detection signal. A motor-rotation-signal generating section generates a motor rotation signal, based on the rotation signal. A phase-difference measuring section measures a phase difference between the motor rotation signal and the mirror rotation signal A prediction-signal generating section generates a prediction signal that is delayed from the motor rotation signal by the phase difference. A switching section switches a control mode between: a mirror control mode in which the mirror rotation signal is used to control a rotational speed of the polygon mirror; and a prediction control mode in which the prediction signal is used to control the rotational speed. A motor driver drives the polygon motor in the selected control mode.

Abstract: A data volume of a data transferred from a ROM to a RAM corresponds to a data volume specified by a data volume information included in a program data. By setting the data volume specified by the data volume information as the data volume of the program data to be transferred, only the program data having the data volume specified by the data volume information can be transferred from the ROM to the RAM. Therefore, an excessive data transfer may not be performed, and the time required for booting a system may not be increased. Also, only by changing the data volume specified by the data volume information, the data volume of the data to be transferred to the RAM can be arbitrarily changed. Therefore, the flexibility to create a program or a program for upgrade is expanded, and a burden imposed on a creator is reduced.

Abstract: A data volume of a data transferred from a ROM to a RAM corresponds to a data volume specified by a data volume information included in a program data. By setting the data volume specified by the data volume information as the data volume of the program data to be transferred, only the program data having the data volume specified by the data volume information can be transferred from the ROM to the RAM. Therefore, an excessive data transfer may not be performed, and the time required for booting a system may not be increased. Also, only by changing the data volume specified by the data volume information, the data volume of the data to be transferred to the RAM can be arbitrarily changed, Therefore, the flexibility to create a program or a program for upgrade is expanded, and a burden imposed on a creator is reduced.