| 摘要 |
PURPOSE:To deal with a position shift by a simple structure when a beam generating source or beam scanning system is replaced and to reduce variation in shift margin, by allowing a beam receiving part to move nearly at right angles to a beam scanning direction. CONSTITUTION:Laser light from a laser light source 2 is passed through an optical system 3 to scan on a photosensitive drum 1 for exposure. A photodetecting member 6 is positioned by being fitted in the hole of the insulating plate 17 of the upper plate 16d of an adjustment plate 16. A circuit part 7 is fixed to the upper plate 16d with a spacer 18 in-between. An adjusting screw 10 pierces a coil spring 19 between the upper plate 16d and lower plate 16e and engages the lower plate 16e thereadably. The screw 20 is rotated to shift a light shielding member 5 and the photodetecting member 6 in position almost at right angles to the scanning direction of the laser light. The laser light illuminates the photodetecting member 6 through a mirror 4 and the light shielding member 5. |
