| 摘要 |
PURPOSE:To obtain always constant image density, by forming a constant potential part of a chargeable member at each modulating actin of ion current, measuring its potential or image density, and replenishing conductive fine powder. CONSTITUTION:A secondary latent image corresponding to primary latent image on a screen 1 is formed on an insulating drum 5 by undergoing ion current modulation of a transfer charger 4. When the nonimage part 1b on the screen 1 is subjected to ion current modulation like the image part 1a, the passing ion current is kept constant by the absence of the primary latent image, and the part 5b' on the drum 5 corresponding to this is kept constant. This part is developed, the density of this developed image is measured, and output of a photodiode 12 is compared with a predetermined value with a comparator 17. The conductive fine powder 21 in a hopper 18 is replenished in accordance with the result, thus permitting controlling by fluctuation of image density by a simple method. |
