| 摘要 |
PROBLEM TO BE SOLVED: To provide an image formation apparatus capable of improving accuracy of density correction.SOLUTION: An image formation apparatus 100 comprises: development devices 3a-3d which include a development roller 31 and a magnetic roller 30; a developing bias power source 46 which applies a developing bias; a density detection sensor 45 which detects toner density of a density correction pattern; and a control unit 42 which controls the development devices 3a-3d and the developing bias power source 46. The control unit 42 makes a first potential difference ΔV1 between the development roller 31 and the magnetic roller 30 immediately before the first density correction pattern is formed larger than the second potential difference ΔV2 when the density correction pattern is formed makes the second potential difference ΔV21 when the first density correction pattern is formed the minimum standard value, makes the second potential difference ΔV22 when the second density correction pattern is formed the maximum standard value, and makes the second potential difference ΔV23 when the third density correction pattern is formed the intermediate value.SELECTED DRAWING: Figure 4 |
