Patent ID: 8493617

Claim:
An image forming apparatus comprising: an image forming device configured to form an image; a computing device; and memory having computer executable instructions stored therein that, when executed by the computing device, cause the image forming apparatus to perform operations including: executing at least image forming position adjustment for correcting an image forming position and image density adjustment for correcting an image density; calculating a single predictive error value for each of a first plurality of variation values and a second plurality of variation values, different from the first plurality of variation values, to obtain a plurality of single predictive error values; calculating a predictive position error value by combining the plurality of single predictive error values for each of the first plurality of variation values; calculating a predictive density error value by combining the plurality of single predictive error values for each of the second plurality of variation values; determining a timing of execution of the image forming position adjustment based on the predictive position error value; and determining a timing of execution of the image density adjustment based on the predictive density error value.