| 摘要 |
PURPOSE:To easily maintain the accuracy of relative positions of a photosensitive drum and an exposing means by maintaining the distance between the exposure means and the photosensitive drum by a guide roller arranged in parallel to the drum shaft. CONSTITUTION:An LED head 2 as an exposing means is guided by a guide shaft 6 whose axis is directed to the center of the drum and energized by a spring 7 toward the photosensitive drum 1 to bring simultaneously the guide roller 5 which is arranged in parallel to the axis of the photosensitive drum 1 and coupled with the LED head 2 into contact with the surface of the photosensitive drum 1. While the guide roller 5 and photosensitive drum 1 are in contact with each other, the photosensitive drum 1 is moved under the guidance of a guide groove 21a at right angles to its axis to absorb force applied at the time of the butting between the drum 1 and roller 5 through the rotation of the roller 5, thereby preventing the surface of the drum 1 from damaging. Further, a process cartridge 12 which supports the drum 1 is extracted at right angles to the axis of the drum 1 in a device-opened state. Consequently, the relative position accuracy between the exposure means and drum surface can be maintained. |
