| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming device constituted so that a laser need not be continuously driven so much in order to detect the rotational frequency of a scanner motor even immediately after the scanner motor is driven. SOLUTION: The image forming device is provided with the laser emitting a laser light beam modulated by an image signal, a rotary polygon body 208 forming a scanning line by reflecting the laser light beam while being rotated, a driving means driving the polygon body 208 to be rotated, a photoreceptor 212 for forming an image at the place thereof irradiated with the scanning line and a photodetector 215 disposed at the end of the scanning line and set for outputting a detection signal when the laser light beam is received. Besides, it is provided with a means detecting the rotational frequency of the driving means based on the pulse width of the detection signal, a means generating and outputting a timing signal by predicting timing in which the photodetector 215 is irradiated with the laser light beam next based on the detected rotational frequency and a means driving the laser based on the timing signal. |
