| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a development device capable of controlling toner concentration highly precisely using a permeability sensor even if a magnetic force generating member is disposed in a screw. <P>SOLUTION: In both a developing screw 42 and an agitating screw 43, magnet sheets 48 are stuck to ridgelines of screw blades of non-magnetic substance. However, in order to correspond to the output fluctuation of a toner concentration sensor 47, a magnet sheet 48 is not disposed on the ridgelines of the screw blades in the vicinity of the toner concentration sensor 47. Then, in a region where the magnet sheet 48 is not disposed, in order to supplement reduction in bulk density of a developer due to reduction in conveyance capability, another screw blade having the same pitch is disposed in a space between the screw blades of the agitating screw 43 having a constant pitch. <P>COPYRIGHT: (C)2012,JPO&INPIT |
