| 摘要 |
PROBLEM TO BE SOLVED: To early put a developing device into a developable state and to suppress a transfer phenomenon of unnecessary toner and carrier onto image carriers, in a mode where a developing voltage is simultaneously applied to a plurality of developer carriers.SOLUTION: A developing device includes: a plurality of developer carriers 1 and 2; a layer control rotating body 4 which is provided so as to be rotatable at least in the same direction in a part facing the first developer carrier 1 having a smooth surface 7a and controls a developer layer held on the first developer carrier 1; development driving means 10 which drives the developer carriers 1 and 2 and developer supply means 3; developing voltage application means 11 which simultaneously applies a developing voltage to respective developer carriers 1 and 2; layer control driving means 12 which performs driving so that layer control operation by the layer control rotating body 4 is switchable; and control means 13 which controls the development driving means, the developing voltage application means, and the layer control driving means in a condition that a toner band and a carrier band are not generated. |
