| 摘要 |
PURPOSE:To perform easily and securely development in plural colors with small-sized constitution by interposing a magnetic shield member between the 1st and the 2nd developing body equipped with a magnetic roll. CONSTITUTION:The developing device 10 drives the developing roller 50 of the 1st developing body and the developing roller 51 of the 2nd developing body selectively to take a color copy of black or one of other colors, e.g. red, yellow, blue, green, etc. Then the device is divided into two, i.e. the 1st developing unit 52 including the developing roller 50 and the 2nd developing unit 53 including the developing roller 51; a black developer with a high frequency of use is used by the 2nd developing unit 53 as a lower stage and a color developer is used by the 1st developing unit 52 as an upper stage. A magnetic plate 140 made of iron is provided as the magnetic shield member between the developing roll 50 and developing roll 51 to reduce the influence of the magnetic flux density and pole distribution upon other magnetic rolls 64 and 64'. Consequently, the constitution is reduced in size, but development is carried out in plural colors easily and securely. |
