| 摘要 |
PROBLEM TO BE SOLVED: To eliminate sweep development even in counter development by making the ratio of the circumferential speed of the surface of an image carrier to that of a toner carrier, the feeding amount of toner which is supplied to an opposed part to the image carrier per unit area and the amount of the toner with which a solid image part is developed per unit area satisfy specified relation. SOLUTION: Developing efficiency means the rate of the amount of the toner with which the solid image part of a photoreceptor is developed per unit time to the amount of the toner carried on a developing roller and fed to a developing area per unit time. Therefore, the developing efficiencyεis obtained asε=MDEV/(MR.θ) when it is assumed that the ratio of the circumferential speed of the surface of the developing roller to that of the surface of the photoreceptor isθ, the feeding amount per unit area of a toner layer supplied to a developing area formed on the developing roller is MR, and the amount of the toner with which the unit area of the solid image part is developed is MDEV. Then, the developing efficiencyεis set to <=0.8. The allowable width of image density is about 0.1 ordinarily, and sweep amount corresponding to the value is 0.1. In order to restrain it equal to or under such a value, the developing efficiencyεmust be set to <=0.8. |
