| 摘要 |
PURPOSE:To improve the detecting accuracy of a permeability sensor by installing the direction of the detecting line of the permeability sensor obliquely against a magnetic line of force formed with a magnetic pole nearest to the permeability sensor, and providing a developer guide plate so as to cover the detecting plane of the permeability sensor with developer. CONSTITUTION:The permeability 5 is installed obliquely by about 45 deg. against the magnetic line (a) of force formed with the magnetic poles N2 and S1 whose directions of the detecting line are set nearest to the permeability sensor 5. A guide plate 7 is positioned so that the upper plane of the developer can sufficiently come in contact with the detecting plane of he sensor 5. Thereby, the number of magnetic lines (a) of force piercing through a magnetic core can be reduced, and the permeability of the developer can be measured without being affected by the magnetic line of force, which improves accuracy. |
