Color shift correcting apparatus and method, image forming apparatus, color shift correcting program and recording medium

A color shift detection pattern forming part forms a color shift detection pattern. A sensor detects color shift in the color shift detection pattern. A color shift amount computing part calculates an amount of color shift. A color shift correcting part corrects the calculated amount of color shift. A correction amount computing part computes an amount of correction to correct the computed amount of color shift. A correcting part corrects the computed amount of color shift based on the computed amount of correction based on a setting value for controlling a color shift state. A determining part determines whether an abnormality is detected in the computed amount of color shift or in the computed amount of correction of color shift based on a result of computation of the amount of color shift or a result of computation of the amount of correction. A fixed value setting part sets a specific fixed value to the setting value of the correcting part.