| 摘要 |
<p>PROBLEM TO BE SOLVED: To use a plurality of developing devices that can easily perform variable adjustment of a developer layer that can be held on a developer holding body in a method using two-component developer, and block the supply of developer to a developing position between the developer holding body and an image holding body for the developing device in a non-developing operation state.SOLUTION: A plurality of developing devices 9 each include: a developer holding body 2 that has a developing rotating body 3, which is formed as a smooth surface 3a having a maximum height of the surface roughness of 5μm or less; a layer regulation rotating body 6 that is arranged opposite to the developing rotating body 3 with a gap; and a developing drive device 10 that drives to rotate the developing rotating body 3 and the layer regulation rotating body 6 during developing operation, and performs variable adjustment of a peripheral speed vof the layer regulation rotating body 6 so as to increase or decrease the peripheral speed vof the layer regulation rotating body 6 in association with the increase or decrease of a developer G layer to be regulated on the developer holding body 2. The developing device in a non-developing operation state drives to rotate the developing rotating body 3, and stops the drive of rotation of or drives to rotate the layer regulation rotating body in a reverse direction at a position opposite to the developer rotating body.</p> |
