| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a development device, capable of accurately measuring toner concentration of developer by preventing developer and toner from sticking on the detection surface of a toner concentration detecting means. <P>SOLUTION: In a developing device 17, a toner concentration sensor 56 is provided in the body 47 of the development device. This toner concentration sensor 56 is moved by a driving means 72, an opening to a developer carrier area on a detection surface 56b of the toner concentration sensor 56 is controlled; and when the toner concentration sensor 56 detects concentration, the detection surface 56b is exposed in the developer carrier area, but in other cases, the detection surface is retracted. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
