| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming device including a developing device with a plurality of developing rollers, configured to prevent an output image from being fogged even if a proces speed is increased, while ensuring sufficient developing performance of the developing device.SOLUTION: A developing roller 21 carries developer including toner and carrier having lower volume resistivity than the toner, and develops an electrostatic image by causing a magnetic brush of the developer to rub a photoreceptor drum 3, while a voltage formed by superimposing an AC voltage on a DC voltage is applied. A developing roller 31 carries developer received from the developing roller 21, and develops an electrostatic image by causing a magnetic brush of the developer to rub the photoreceptor drum 3, while a voltage formed by superimposing an AC voltage on a DC voltage is applied. Drive motors 50, 60 rotate the developing roller 21 and the developing roller 31 at a higher peripheral-speed than that of the photoreceptor drum 3. The drive motors 50, 60 rotate the developing roller 31 at a lower peripheral-speed than that of the developing roller 21. |
