| 摘要 |
PURPOSE:To prevent deterioration in picture quality and the formation of a black line even when the peripheral speed of a photosensitive body varies by increasing or decreasing the intensity of a light beam according to variation in the peripheral speed. CONSTITUTION:A peripheral speed detector 9 projects light upon plural holes 12 formed in a rotary disk 11 which moves interlockingly with the photosensitive body 1 to detect them. Then, a control circuit 10 which varies the light intensity output of a semiconductor laser 2 is provided. For example, when the photosensitive body 1 increases in peripheral speed, that is detected by holes 11 and the detector 9 and the intensity of the laser 2 is increased by the circuit 10 to increase a beam spot diameter. This is attained by increasing the beam spot diameter when subscanning pitch increases to prevent the generation of a gap. Consequently, the formation of a black line is prevented even during, for example, positive development to prevent the deterioration in picture quality. |
