| 摘要 |
PURPOSE:To perform accurate toner density control by providing a control means which does not extract information on toner density for a developer stagnating for longer than a specific time. CONSTITUTION:A device which performs toner density control by measuring the reactance of a coil does not control toner density correctly when toner is high in density owing to pressure application, etc., so the density measured value of a developer left for longer than the specific time while stagnating at a reservoir part is extracted and only the density measured value of a developer 11 reserved at the reservoir part 5 at specific time after the developer 11 is discharged temporarily is extracted. Namely, the density measured value is extracted only when a magnet 31 passes by a Hall element 32 within the specific time after the magnet 31 passes by a Hall element 33. |
