| 摘要 |
PURPOSE:To automatically detect the residual amount of a toner by providing an optical detecting means consisting of a light emitting element and a photodetector, and capturing the light falling to a developing roller and reflected therefrom. CONSTITUTION:A detecting part 9 provided with a light source 11 and a photosemiconductor element 12 is disposed in proximity to a developing roller 4, and is mounted to a stationary bracket 10. The element 12 constitutes one side of a bridge circuit, and with a change in the resistance value of this element 12, a potential difference is generated in the bridge, by which a detecting lamp 15 is lighted or other alarm device is operated. In this way, the residual amount of the toner is detected automatically with a slight expense; nevertheless, the device for this purpose is mounted to the machine frame irrespective of the mounting and dismounting of a toner receiving hopper and separately from the developing part. |
