| 摘要 |
PURPOSE:To prevent a developer, etc., from sticking on a detection window member and to prevent an ATR signal from being misdetected by providing a vibration application means which applies vibration to a developer concn. detection and controller (ATR) detection window member at specific timing. CONSTITUTION:When a latent image on an image carrier 4 is developed for visualization, a developing sleeve 3 is applied with an AC vibrating electric field and a DC bias by a power source 15 and toner sticks on the image carrier 4 from the developing sleeve 3. After the development ends, the ATR detection window member 17 is vibrated with an ultrasonic wave of 50V and 50 kHz from an ultrasonic vibrator 16 at timing where an ATR signal is not detected to propagate a progressive wave inward from the front. Thus, the ATR detection window member 17 is vibrated with the ultrasonic wave to prevent toner, etc., from sticking on the window member 17. Consequently, the ATR signal is prevented from being misdetected. |
