Patent ID: 8463147

Claim:
An image forming apparatus comprising: an image bearing member configured to bear an image; a transfer member to which the image can be transferred from the image bearing member; a correction-image-formation control unit configured such that, on the transfer member, a bias correction image is formed based on an uncorrected bias and a first parameter-correction image is formed behind the bias correction image based on the uncorrected bias and an uncorrected image-formation parameter with no intervening correction image; a bias correcting unit configured to obtain a corrected bias by correcting the uncorrected bias based on the bias correction image; a bias determining unit configured to determine whether the corrected bias is within a predetermined range defined based on the uncorrected bias; a parameter correcting unit configured to obtain, if the corrected bias is within the predetermined range, a corrected image-formation parameter by correcting the uncorrected image-formation parameter based on the first parameter-correction image; and wherein if the corrected bias is outside the predetermined range, the correction-image-formation control unit causes a second parameter-correction image to be formed after the first parameter-correction image based on the corrected bias and the uncorrected image-formation parameter, and the parameter correcting unit obtains a corrected image-formation parameter by correcting the uncorrected image-formation parameter based on the second parameter-correction image.