| 摘要 |
PURPOSE:To detect the density of a reference visible image, after copying, with the image being at rest relatively, to accurately detect the density and to control the image density so that it becomes proper. CONSTITUTION:When an exposure means 3 forms a reference latent image on a photosensitive drum 1, the reference latent image is developed by developing units 5a, 5b, 5c and 5d to become the reference visible image. The reference visible image is transferred by a transfer amber 25 composing a part of the periphery of a transfer drum 26. Thereafter the transfer member 25 rotates 180 degrees, so that the reference visible image faces a density detecting device 27, which measures the density of the reference visible image. Based on the result of the measurement, a CPU 19 controls a developing bias power source 15. |
