| 摘要 |
PROBLEM TO BE SOLVED: To precisely detect a toner end state when the lowering of density is small. SOLUTION: This developing device is constituted so that an electrostatic latent image on a latent image carrier 1 is visualized while toner in a toner storage means 2 is successively replenished. Then, it is provided with a density detection means 3 detecting the density corresponding to a toner image formed on the carrier 1, a change quantity calculation means 4 calculating the secular relative change quantity of the density detected by the detection means 3 and a toner end discrimination means 5 discriminating the vacancy of the storage means 2 based on the relative change quantity calculated by the calculation means 4. Besides, an environmental change detection means 6 and an increasing inclination discrimination means 7 for the density are added to the detection means 4. Moreover, a preliminary anouncement means 8 for the toner end state and a trouble judgement means 11 for preventing the storage means 2 whose vacancy is detected from being reset are added to the discrimination means 5. |
