| 摘要 |
PURPOSE:To accurately calculate the content ratio of toner in developer by installing the direction of a detecting line of a permeability sensor obliquely against a magnetic line of force formed with a magnetic pole nearest to the permeability sensor. CONSTITUTION:The permeability sensor 5 is installed 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 obliquely by about 45 deg.. Thereby, the number of magnetic lines of force piercing through a magnetic core can be reduced, and the measurement of the permeability of the developer can be performed without being affected by the magnetic line of force, and the content ratio of the toner in the developer can accurately be calculated. |
