| 摘要 |
PURPOSE: To simplify the structure of a developing device and to cut running costs. CONSTITUTION: An amount of toner 32 remaining in the developing device 30 is found by detecting the value of an electrification current supplied to a developing roller 33 from a DC power source 35. When the toner 32 in its toner container 31 is used and the amount of remaining toner becomes small, the value of the current increases as shown in the figure (2). A sufficient seal is provided between each end of the developing roller 33 in its axial direction and the side wall of the toner container 31, therefore the toner 32 is prevented from leaking and the running costs are also cut. |
