| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming device capable of suppressing one part of a toner moving from a developing unit to an image carrier corresponding to color printing at monochrome printing time, in the image forming device in which an AC power source circuit for outputting an AC component of a developing bias is made to be common in all colors.SOLUTION: An image forming device 1A includes: a photoreceptor drum 11; a developing unit 13; and a development bias power source 40 for applying a developing bias to the developing unit 13. The development bias power source 40 has: an AC power source circuit 50 common to all colors; DC power source circuits 60 provided for each of plurality of colors; and a Zener diode 70 for maintaining a constant voltage irrespective of output from the DC power source circuits 60. The constant voltage maintained by the Zener diode 70 has opposite polarity from a toner. The development bias power source 40 further superposes the constant voltage by the Zener diode 70 to the developing bias corresponding to at least one color other than a black color. |
