| 摘要 |
PURPOSE:To prevent disturbance light and to improve detection precision by inserting and fixing a light quantity sensor which detects the quantity of light from an original illumination lamp and a density sensor which detects original density in holes of a light shield member which is bored toward an object of detection. CONSTITUTION:The light shield member 13 is provided under contact glass where an original is placed. A hole 13a is bored in this member 13 toward the original illumination lamp and the light quantity sensor 8 is provided. Further, a hole 13b is bored toward the original and the density sensor 11 is provided. Then, the light quantity sensor 8 detects the quantity of light and performs control so as to hold the quantity of light constant. The density sensor 11 detects the original density and controls a developing bias voltage to optimize image density. Thus, the light quantity sensor and density sensor are provided in the holes in the light shield member, so external scatter light is cut off to allow the sensors to operate precisely, and the device is made compact. |
