| 摘要 |
PURPOSE:To detect the residual quantity of a developer with a simple mechanism by detecting the residual quantity of the developer based on the detected result of a magnetic body position with a sensor. CONSTITUTION:Magnetic developer is filled in a developer tank 21 and the magnetic body 22 is movably provided on the side part of the developer tank 21 in the direction perpendicular to the developer tank. As for a sensor 23, any devices which can detect the position of the magnetic body 22 are avilable, for example, an optical sensor and a micro switch. And plural sensors may be provided. A residual quantity detecting device 24 obtains the residual quantity of the developer from the combination of results etc., detected by the plural sensors 23. In such a manner, the position of the magnetic body is detected to know the existence of the developer at the point of the magnetic body, by taking advantage of the fact that the magnetic body 22 moves in response to the presence or absence of the developer in the developer tank. Then, the residual quantity of the developer can be detected from the presence or absence. |
