| 摘要 |
PURPOSE:To make the conditions at the judgement of developing ability always constant by letting the developer to be compared with a reference quantity be deposited on the transparent counter electrodes in the measuring developer and cleaning the electrodes by an electrode wire and the flowing-down developer. CONSTITUTION:When the circulating developer in a hopper 1 becomes of a fixed quantity, a valve 2 opens, allowing the developer to flow down the guide tube 3. While it is being held stored at a fixed quantity in the portion of a small sectional area of channel provided with opposing transparent electrodes 4, 5, it is discharged from the tube 3. As a result, the developer of the quantity corresponding to its developing ability under always fixed conditions deposits on the electrodes 4, 5 being driven by AC. The quantity of deposition is optically detected and the developing ability is judged by the comparing arithmetic circuit 17 to which a reference signal is applied. The developer having deposited is cleaned by application of the DC voltage of a polarity opposite from that of the toner on the electrode wire 7 at the intermediate of the opposing space of the electrodes 4, 5 and sliding of the developer flowing down from the hopper 1, thus the developing ability is accurately judged under required constant conditions and the developing ability is well controlled by replenishment, etc. of the toner in correspondence thereto. |
