Image forming apparatus, image processing apparatus and method capable of determining image forming condition when color unevenness caused in patch image is detected

摘要

The present invention provides a mechanism that more appropriately evaluates an image defect caused by a specific process in an image forming apparatus. An image forming apparatus of this invention performs colorimetry of a patch image at a spatial resolution corresponding to the spatial frequency of color unevenness caused by a specific process included in an image forming process. A statistic value based on the n-th (n is an integer of 2 or more) order central moment of a specific color component of a colorimetric value obtained by performing colorimetry at the spatial resolution is compared with a reference value, thereby detecting that the color unevenness caused by the specific process has occurred in the patch image.

主权项

1. An image forming apparatus comprising:
an image forming unit that forms, on a recording material, a patch image to be used to detect color unevenness by executing an image forming process including a plurality of processes; a colorimetry unit that performs colorimetry of the patch image formed on the recording material at a spatial resolution corresponding to a spatial frequency of color unevenness caused by a specific process included in the image forming process, thereby obtaining a colorimetric value; a detection unit that detects that the color unevenness caused by the specific process has occurred in the patch image by comparing a statistic value based on an n-th (n is an integer not less than 2) order central moment of a specific color component of the colorimetric value obtained by said colorimetry unit with a reference value; and an adjustment unit that, when said detection unit detects that the color unevenness caused by the specific process has occurred in the patch image, adjusts an image forming condition concerning the specific process so as to reduce the color unevenness.