| 摘要 |
PURPOSE:To accurately control toner contents by electrically detecting the toner contents through the developer layer formed by a magnetic brush method. CONSTITUTION:A developer conveying means 104 disposed on a substrate 101 secured with plural permanent magnets 102 is formed of a non-magnetic and conductive material and an insulation layer 104' is applied on the outer surface thereof. A counter electrode 12 is formed of a conductive material. Then, when the developer layer d' formed on the conveying means 104 through relative revolution with the magnet groups 102 contacts the counter elecftrode 12, then the bias voltage from a bias power surce 11 flows to the counter electrode 12 through the developer layer d', and isthen compared with a reference voltage in a comparing control circuit 14, whereby the toner contents are electrically accurately detected. |
