| 摘要 |
PROBLEM TO BE SOLVED: To adjust the quantity of a light beam with which a photoreceptor is irradiated through low-cost, simple constitution. SOLUTION: A semiconductor laser and a collimator lens are stored in a housing 18 which is allowed by frames 22 and 24 to move only as shown by the arrow A, and shims 28 are stacked between the case 18 and a base 20. An aperture 32 having a slit 36 is arranged on the beam projection side of the casing 18. The width of the slit 36 is less than the beam diameter and the light quantity of the beam matches a Gaussian distribution, so when the relative position between the beam light axis and slit 36 is changed by increasing or decreasing the number of shims 28, the light quantity of the laser beam emitted through the slit 36 varies. Therefore, the variation range of the irradiation light quantity of the laser beam to the photoreceptor drum can be adjusted by adjusting the number of the shims 28. |
