| 摘要 |
PURPOSE:To prevent a toner run-out by placing a coil in a laminated area of a toner having a magnetism, detecting an inductance variation of a coil, and obtaining a remaining quantity detecting output of a toner by plural stages of three stages or more, or continuously. CONSTITUTION:A follow-core coil 10 is installed to the outside surface of a toner box 2 formed by an insulating material so that a hand direction becomes a vertical direction. An inductance of the coil 10 is varied by a relative position to the coil 10 of an upper face 1a of a toner 1. The smaller a quantity of the toner 1 is, the better a line of magnetic force of the coil 10 passes through in the air, therefore, by a difference of a magnetic permeability of the air and the toner, the inductance is varied so as to become small. A voltage output of an F/V converter 12 is inputted to a window comparator 16 having a comparison reference of several stages and compared, and by its comparison output, several indicators 17 are driven, by which a toner remaining quantity can be known comparatively in detail, and a toner run-out can be prevented. |
