| 摘要 |
PURPOSE:To detect stably a toner density in a high-density developer with a high precision, by eliminating a leakage magnetic flux and forms magnetic paths effectively. CONSTITUTION:In respect to a density detector 1, a pair of iron plates forming magnetic paths 2 and 2 are arranged to be brought into contact with each other bilaterally, and a coil 3 is wound around magnetic paths 2 and 2 in this contacting position, and an angular pipe 4 is arranged on the outside of magnetic paths 2 and 2 brought into contact with each other, and magnetic shield members 5 are arranged on the outside of the angular pipe 4, and the density detector 1 is formed to a shape like an angular pipe as the whole. In respect to magnetic paths 2, a pair of iron plates formed to rectangles are arranged at a prescribed interval so as to face each other, and these iron plates are formed to a shape like U as the whole. The detector 1 is stored in a nonmagnetic pipe body 8. When a developer 10 is packed and an AC current is applied to lead wires 6 and 7 of the coil 3, a magnetic flux 9 is generated; and whether the developer 10 is packed or not, a magnetic flux 11 is generated. |
