| 摘要 |
PURPOSE:To eliminate the danger of an electric shock by acting the oscillation of an ultrasonic oscillator on a corona discharge wire and dislodging the foreign matter sticking thereto in the stage of corona discharge so that the stable discharge condition is maintained for long time and that the discharger is disconnected from a supply source for a high voltage at the same instant when the wire is broken. CONSTITUTION:A photosensitive body starts rotating and at the same time an oscillating circuit 18 is operated by the timing signal from a timing signal circuit 20. The oscillated output is supplied to an ultrasonic oscillator 12. The oscillator 12 oscillates in the direction of the arrow according to the piezo-electric characteristic thereof, thereby oscillating a corona discharge wire 14 pressed thereto via an insulating member 16. The foreign matter sticking to the corona discharge wire is thus dislodged and removed during discharge. The contact point between the ultrasonic oscillator and the corona discharge wire is so constituted as to be brought on the high voltage input side of the corona discharge wire and in a non-image region. Therefore when the wire 14 is broken owing to rubbing with the oscillator 12, the discharge device is disconnected from the high voltage input side and there is no possibility of an electric shock, etc. |
