Patent ID: 8200107

Claim:
An image forming apparatus comprising: an image bearing member configured to form an electrostatic latent image on a surface thereof in accordance with image data; a developer bearing member having a developer bearing surface at least a partial region of which faces the image bearing member and configured to be driven so as to feed a developer to the image bearing member; a required amount detecting section configured to detect a detection value related to an amount of toner required by an image to be formed during image formation in accordance with image data; a velocity adjusting section configured to set a relative velocity of the developer bearing member to the image bearing member to a predetermined value when the detection value is equal to and more than a threshold value and set the relative velocity to a lower value than the predetermined value when the detection value is less than the threshold value; a bias voltage detecting section configured to detect a developing bias voltage value; and a nonvolatile storage section configured to store therein a developing bias voltage value obtained before powering-OFF, wherein the velocity adjusting section is configured to correct a set value of the relative velocity to a higher value when an absolute value of a developing bias voltage value which is detected by the bias voltage detecting section after powering-ON is more than an absolute value of an average value of developing bias voltages previously stored in the nonvolatile storage section.