| 摘要 |
PURPOSE:To set an appropriate density to an original by determining an image forming condition in accordance with the output of a photodetecting element after the photodetecting element is automatically cleaned before making image formation and performing the image formation. CONSTITUTION:Rays from a lamp 2 and reflection mirror 3 irradiate a photosensitive drum 10 through a lens 4, original 1, mirrors 6 and 7, and the slit 9 of a slit plate 8. A supporting body 11 supports the mirrors 6 and 7 in one united body and moves synchronously to the slit plate 8 and photosensitive drum 10. A photodetecting element 20 is provided in the vicinity of the slit 9 and preliminary scanning is performed by moving the mirrors 6 and 7 from their home positions after the photodetecting element 20 is cleaned by a brush not shown in the figure. After the preliminary scanning, the electric current to the lamp 2 is adjusted by controlling the luminance of the lamp 2 by means of a control circuit 27 from the detected maximum and minimum luminous intensities. Normal exposing and copying processes are performed thereafter. Therefore, copies of appropriate density are obtained by performing exposure in accordance with originals. |
