| 摘要 |
PURPOSE:To improve reproducibility in the vicinity of the density 1.0 of an original by providing a control means capable of setting the target value of the concentration, thereby changing the target value of the concentration of an ADC when a developing curve is changed. CONSTITUTION:The optical density of a reference potential part (patch) is detected by an ADC senser 31, the concentration of toner is controlled by a controller 30 in accordance with a detected result. Firstly, image quality is made optimum by optimizing the light quantity of a lamp 3 and positioning the corotron of a transferring device 26 to a photosensitive material drum 20, etc. Thereafter, the patch is formed at shorter interval than a regular copying mode in a self-diagnostic mode, the target value of the ADC is calculated by reading the concentration of the patch detected by the ADC senser 31 and is set to a nonvolatile memory 32. When color toner is used, e.g. when red toner is used, the target value is corrected based on the calculated target value and the target value of other color is set, as well. |
