| 摘要 |
PURPOSE:To prevent a deterioration in an electret layer and to prolong the life of a developing device by specifying an angle formed by a straight line that links the top end of a toner layer thickness adjusting blade and the center of an electret sleeve and a horizontal plane. CONSTITUTION:The developing device is provided to face a photoreceptor drum 50 and with a rotary driving electret sleeve 2 and a rotary fur brush 3 which does not come into contact therewith, in a developing container 1 and the electret layer 2a having a permanent charge having a polarity reverse to that of the static charge characteristic of toner is formed on the surface of the electret sleeve 2, to hold and carry the charged toner 5 by electric attracting force. Further, the toner layer thickness adjusting blade 7 is provided with an interval of 50-300mum from the electret sleeve 2 and the charged toner 5 is adjusted to a constant thickness and supplied to a developing area. At this time, the blade 7 is provided in a position where the angle alpha formed by the straight line Q that links the top end of the blade 7 and the center of the electret sleeve 2 and the horizontal plane is in a range from 30 deg. to -90 deg.. |
