| 摘要 |
PURPOSE:To accurately detect that the quantity of replenishment toner is smaller than a prescribed value with a simple structure, by controlling the toner empty operation based on the result of comparison between the measured result of a toner concentration measuring means and a preliminarily set reference. CONSTITUTION:A toner concentration measuring means 14 measures the toner concentration of a developer and sends the measured result to a first comparing means 16 and a second comparing means 17 through a control means 19. The means 16 compares the measured result with a first reference value and sends the comparison result to the means 19. The means 19 operates a toner replenishing means 13 in accordance with the comparison result of the means 16 to control the toner concentration of the developer. Meanwhile, the means 17 compares the measured result with a second reference value and sends the comparison result to the means 19. The means 19 operates a display means 18 in accordance with the comparison result of the means 17 to not only display the empty state but also stop the image forming operation of an image forming device. Thus, it is accurately detected that the quantity of replenishment toner is smaller than the prescribed value, and the structure of a toner hopper is simplified. |
