Image forming apparatus and density correction method

An image forming apparatus comprising:

• a sheet conveyance section capable of conveying a long sheet;
• an image forming section including a rotational member and configured to form an image on the long sheet, the rotational member including a photoconductor and a developer bearing member;
• a density unevenness cycle acquiring section configured to acquire a cycle of a density profile that represents density variation in a sub scanning direction;
• a cycle control section configured to operate such that, in a case where a same image is continuously formed on the long sheet, a length of the image in the sub scanning direction is an integer multiple of a cycle length that corresponds to one cycle of the density profile;
• an image density detection section configured to detect a density of an image formed by the image forming section on an image bearing member;
• and
• a density correction section configured to form a patch image for correction that has a size greater than the cycle length of the density profile on the image bearing member, and, based on a detection result regarding the patch image for correction that is obtained by the image density detection section, create correction data to perform density correction using the correction data.