| 摘要 |
PURPOSE:To detect exactly a toner density by providing an auxiliary magnetic pole of the opposite polarity between the same pole opposed parts, respectively, and placing a toner density detecting member in the vicinity of this auxiliary magnetic pole. CONSTITUTION:When a nonmagnetic sleeve 4 is rotated in the direction as indicated with an arrow X, a developer 2 adsorbed onto the sleeve is carried toward a developing gap D from a doctor gap (d). In the vicinity of the developing gap D, the surface of a photosensitive drum 1 is slid and rubbed by a magnetic brush formed by the developer 2, and an electrostatic latent image formed on the drum 1 is developed. When the developer 2 which has passed through the developing gap D reaches the same pole opposed part, it is scraped down from the nonmagnetic sleeve 4 and collected into a developer tank 3. The collected developer 3 is stirred and mixed by an impeller 9 together with a toner 2a discharged from a toner tank 10 by a rotation of a toner feed roll 13, and thereafter, attracted onto the nonmagnetic sleeve 4 again and used for a development. |
