| 摘要 |
PURPOSE:To easily, inexpensively and stably pass a developer in a magnetic permeability sensor and to allow the control of a toner concn. by providing a mesh which is smaller than the diameter of the narrowest part and larger by >=10 times the diameter of the carrier in the developer in the upper part of the funnel-shaped developer take-in port of the magnetic permeability sensor. CONSTITUTION:The mesh 13 is provided in the upper part of the funnel-shape developer take-in port 11b of the magnetic permeability sensor 11 and, therefore, the developer falling and passing the inside of the magnetic permeability sensor 11 is past the mesh 13. Since the opening of the mesh 13 is smaller than the diameter in the narrowest part of the funnel-shaped developer take-in port 11b, the large impurities are removed and the clogging is prevented. The opening of the mesh 13 is sufficiently larger than the carrier diameter to prevent the clogging of the carrier in the mesh 13 part and the impairment of the flow of the developer. In addition, the bridging of the developer 12 in the mesh 13 part is obviated as well. The developer is easily, inexpensively and stably passed in the magnetic permeability sensor, by which the control of the toner concn. is executed. |
