| 摘要 |
PROBLEM TO BE SOLVED: To improve an installation environment for an image forming apparatus, save resources and reduce the size of the apparatus, and extend the life of a black imaging unit.SOLUTION: An image forming apparatus forms images in a plurality of colors Y, M, and C including a color K with respective imaging units 10K, 10Y, 10M, and 10C, and overlaps the formed images to form a color image. The image forming apparatus applies a voltage obtained by superimposing an AC voltage on a DC voltage to a charging device 22 of an imaging unit 10K that forms images in color K (black), and applies only a DC voltage to charging devices 22 of the imaging units 10Y, 10M, and 10C that respectively form images in colors Y, M, and C other than the color K. |
