| 摘要 |
PROBLEM TO BE SOLVED: To obtain a developing device capable of obtaining a good image without roughness and density fluctuation especially on a halftone area. SOLUTION: Two-components developer 413 having a toner whose average particle size is 6 μm is initially stored in a developing device 41 and the toner whose average particle size is 4 to 3 μm is stored in a toner hopper 411 as the toner 4111 for replenishment. Reflection density measurement of a halftone dot toner image obtained after development is successively performed by a reflection density sensor and toner replenishment is delicately performed in accordance with the measuring result. Thus, the roughness and the density fluctuation are eliminated especially on the halftone area. |
