| 摘要 |
PROBLEM TO BE SOLVED: To provide an image forming apparatus employing a counter developing system, in which a high-quality image can be stably formed without inducing retention of a developer near an opposing part between a developer carrier and an image carrier even when an image is formed at a lower drive speed of the developer carrier compared to a normal process.SOLUTION: A developing device 4 includes a photoreceptor drum 1 carrying an electrostatic latent image and a developing sleeve that carries a two-component developer comprising a toner and a carrier and develops the electrostatic latent image on the photoreceptor drum 1 to form a toner image. Advancing directions of the photoreceptor drum 1 and the developing sleeve are opposite to each other in an opposing part. The developing device also includes: a speed varying unit 19 for varying a drive speed of the developing sleeve; and a control unit 50, which changes a target speed of the developing sleeve upon executing a low-speed mode of driving the photoreceptor drum 1 at a rotational speed lower than a speed in normal image formation, in such a manner that before the developing sleeve is driven at a first speed set for the low-speed mode, the developing sleeve is driven at a second speed higher than the first speed. |
