| 摘要 |
PURPOSE:To control toner density of two-component developer at high accuracy by detecting level of the surface of developer in a developing device by an electrostrictive vibrator. CONSTITUTION:The developing device consists of a container 5 that contains developer containing toner, magnetic brush forming devices 2, 3 that bring developer in the container 5 into contact with a photosensitive drum 1, a partition panel 8 lying close to the sleeve 2 and an agitating roll provided near the partition panel 8 and electrostrictive vibrator 14. As the photosensitive drum 1 is developed, toner in the container 5 is consumed successively and the surface level A of developer 4 becomes lower. When the surface level A of developer is above sensitivity, the electrostrictive vibrator gives output of 12V. When the level is arrived at sensitivity level, vibration is made between 0V and 12V. When lower than the sensitivity level, output of 0V is given. A toner replenishing roll is driven when output becomes 0V, and stopped when output becomes 12V. Thus, proper toner density is maintained. |
