| 摘要 |
PROBLEM TO BE SOLVED: To control the rotation of a motor with a simple circuit constitution. SOLUTION: The image forming device is provided with a rotary n-face mirror which is rotated in accordance with the drive of a laser scanner motor connected to a motor driver so as to reflect modulated laser beams emitted from a laser beam source by several reflection surfaces, a sensor for receiving the light reflected by the rotary polygon mirror and outputting a reference signal showing the writing start position in a main scanning direction on an image carrier, a measuring means for measuring the time interval between the reference signals outputted from the sensor, a calculating means for calculating the measured value for the single rotation of the rotary n-face mirror, a comparison means for comparing the measured value for the single rotation of the rotary n-face mirror with a reference value, and the device is also provided with an acceleration/reduction signal control means for adding the measured value of the new reference signal interval to the measured value for the single rotation of the rotary n-face mirror in synchronism with the reference signal, and then, outputting the acceleration signal/reduction signal based on the comparison result obtained by comparing the result obtained by reducing the measured value before n-pieces with the reference value by the comparison means. |
