| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming device by which a developer containing carrier is supplied into a developing vessel, a development apparatus for discharging a surplus developer is included and supply of a new developer can be properly performed in accordance with the degree of deterioration of the developer in the development apparatus.SOLUTION: The number of accumulated printed sheets reaches the predetermined number of sheets, a control part forms a plurality of patch images on a photoreceptor drum and transfers them onto an intermediate transfer belt. Next, the density of each patch image is detected by a density detection sensor, and based on a detection result, the charging amount distribution of toner and its work function distribution are calculated. Then, deterioration level of a developer is determined using relationship between the work function distribution and the deterioration rank of the developer calculated by a particle simulator in advance and stored in ROM. Furthermore, based on the determined deterioration level, the supply level of the developer (supply amount and supply interval) is determined. |
