| 摘要 |
PURPOSE:To prevent density reducing phenomenon caused by selective development by forming a toner image outside an image area with development contrast higher than development contrast in the image area and with prescribed width. CONSTITUTION:An erasing exposure 20 is putted-out at a part outside the image area. When a developing bias DC component is set at -50V, development is performed with the development contrast of +450V, and, for example, a belt-like toner image with the width of 2mm is formed. That is, at a part outside the image area, the belt-like toner image is formed with the contrast higher than the development contrast in the image area and thereby, toner particles which remain on a developing sleeve 31 and are difficult to be developed are conveyed onto a photosensitive drum 10 and ejected from a developing device. Thus, the toner particles which are difficult to be developed are prevented from being accumulated in the developing device and the developing sleeve, and density reduction caused by duration is prevented. |
