| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which allows rotational phases of polygon mirrors to efficiently agree with one another. <P>SOLUTION: A CPU 91 is provided with: a beam detection part 911 for detecting laser beams respectively scanned by polygon mirrors 332 of the prescribed number (herein, four pieces) in positions preset on scanning paths (disposition positions of a beam sensor 335); a reference phase setting part 912 for setting reference phases each of which is a phase becoming the reference of rotational phase of the polygon mirrors 332, based on the detection result of the beam detection part 911; a phase difference calculation part 913 which determines a phase difference between the reference phase and the rotational phase of a polygon motor 330 every time the laser beam is detected by the beam detection part 911; a frequency presetting part 914 for presetting a rotational frequency of the polygon motor 330, based on the determined phase difference; and a frequency control part 915 for controlling the rotational frequencies of the polygon motors 330 into the preset rotational frequencies. <P>COPYRIGHT: (C)2008,JPO&INPIT |
