| 摘要 |
PROBLEM TO BE SOLVED: To surely detect whether or not the sufficient amount of magnetic toner exists by a magnetic permeability detector, by making the toner periodically flow toward a magnetic permeability detection surface, also analyzing the output signal of the magnetic permeability detector and discriminating the toner amount. SOLUTION: A toner detecting means 80 includes the related magnetic permeability detector 82 to one end part of a toner carrying path 36. The leading end part of the detector 82 is positioned in an opening 84, the detection surface 86 of the detector 82 is exposed on the toner carrying path 36 through the opening 84. The detection surface 86 is inclined at an inclined angleθwith respect to the horizontal plane. And, the output voltage of the detector 82 is changed in accordance with a magnetic resistance near the detection surface 86. That is, when a large quantity of magnetic material exists near the detection surface 86 and the magnetic resistance is small, the large output voltage is generated, meanwhile, when a small amount of magnetic material exists and the magnetic resistance is large, a small output voltage is generated. Thus, even when the toner is slightly magnetic, the toner is surely detected. |
