| 摘要 |
PURPOSE:To allow a crystal oscillation module to adjust the scanning width of scanning beams over a wide range by adjusting the rotational speed of a rotary polygon mirror and correcting the variance of the scanning width of scanning beams based upon the variance of characteristics of a condenser lens. CONSTITUTION:A rotary clock is rotated on the basis of a set point S to obtain a printing sample 21. The scanning width A of the sample 21 is measured to check the difference between the scanning width A and a logical value R. In case of A>R, the rotational speed of the rotary polygon mirror is reduced, and in case of A<R, the speed is increased. The adjusting value + or -x of the obtained rotational speed is stored in a ROM 27. Thus, the adjustment of the scanning width is completed. After adjustment S, + or -x is used as a phase locked loop (PLL) clock frequency for rotating the polygon mirror and the operated result is set up in a timer 28 to output a printed result obtained by correcting the variance of the scanning width due to the dispersion of the characteristics of the condenser lens. |
