| 摘要 |
PURPOSE:To increase the absolute quantity of tone held on a developing sleeve by arranging toner concentration detecting sensors correspondingly to both the sides of an electrostatic latent image carrier and expanding a crest height regulating gap on a position where the toner concentration is reduced based on the results obtained by the sensors. CONSTITUTION:The toner concentration detecting sensors 81, 82 are arranged on the depth side and front side of a carrier 26a so that the surfaces of respective sensors aligned on almost the same plane as the carrier 26a to detect toner concentration Ia, Ib of developer carried on the carrier 26a. When the toner concentration values Ia, Ib detected by the sensors 81, 82 arranged on the depth side and front side are decided as values lower than reference concentration Io, the crest height regulating gaps Db1, Db2 are immediately expanded, so that the absolute quantity of the developer held by the developing sleeve 24 on the sides corresponding to the sensors 81, 82 is increased and the quantity of toner carried to a developing area X can be practically increased. Thus, the drop of the toner concentration can be removed. |
