| 摘要 |
PURPOSE:To prevent the print quality from decreasing owing to ground staining and an irregularity in image density by correcting the recovery bias of a supplementing and recovery bias applying means for a toner recovery mode according to the result of a comparing means which compares the detected potential of a potential detecting means with a reference potential. CONSTITUTION:In the recovery mode after development, the recovery bias is applied from the supplementing and recovery bias applying means 19 to a supplementing roller 5 to collect a developer 2 left on a developing sleeve 7, but the potential detecting means 21 detects the potential of a conductive member 11 which contacts the developer on the developing sleeve 7 before the collection. Then a correcting means corrects the recovery bias according to the result of comparison between the detected potential and reference potential. Therefore, the collection amount of the developer left on the developing sleeve 7 can be uniformed and the supplementary amount of a next developer can be uniformed. Consequently, the ground staining is precluded and the image density is stabilized. |
