Patent ID: 7536136

Claim:
An image forming apparatus comprising: a rotatable developing device incorporating a plurality of first developer units; a second developer unit disposed outside the rotatable developing device; a photoconductor on which a toner image is capable of being formed by contact of each of the first and second developer units; a driving motor configured to rotate the rotatable developing device; and a motor controller configured to control the rotation of the rotatable developing device by the driving motor so that the toner image is formed on the photoconductor by the second developer unit first, then the toner image is formed on the photoconductor by each of the first plurality of developer units sequentially, wherein the motor controller controls to rotate the rotatable developing device with a first angular acceleration while development is performed by the second developer unit, and controls to rotate the rotatable developing device with a second angular acceleration when development is performed by one of the plurality of first developer units proceeds to development by a next one of the plurality of first developer units, and wherein the first angular acceleration is set to be smaller than the second angular acceleration.