| 摘要 |
PROBLEM TO BE SOLVED: To stably measure toner concentration by effectively preventing accumulation of developer near a toner concentration sensor even when speeding-up of development is achieved or even when fluidity of the developer changes. SOLUTION: The developing device 100 is equipped with a stirring roller 113 arranged in a housing 111 and mixing and stirring toner that is non-magnetic substance and carrier that is magnetic substance, and the toner concentration sensor 130 arranged in the housing 111 and detecting concentration of the mixed and stirred toner of the developer. Magnetic substance 140 preventing the accumulation of the developer is arranged near the toner concentration sensor 130 on the outside of the housing 111. COPYRIGHT: (C)2009,JPO&INPIT |
