| 摘要 |
PURPOSE:To completely remove the variance in output voltage or to suppress it and to execute accurate concentration detection and its control by arranging an oscillation coil oppositely to the section of an outer member consisting of a conductive material forming a developer tank. CONSTITUTION:A bobbin 2 incorporating an adjusting screw core consisting of a high-permeability material is mounted on a base 1 and a concentration detecting coil 3, an oscillation coil 4 and a comparing coil 5 are wound around the bobbin 2. After storing the base 1 mounting the bobbin 2, a case 6 is tightly closed by a cover 7 and fitted to the outer member 8 consisting of aluminum so that the coil 3 faces to the developing tank and contacts the developer at that part. The oscillation coil 4 is arranged oppositely to the section of an outer member 8. Consequently, the influence of the coil 3 or 5 upon inductance can be completely removed or suppressed and accurate concentration detection and its control can be attained. |
