Patent ID: 8270857

Claim:
An image forming apparatus comprising: an image forming unit that forms a toner image; a temperature measuring unit that measures an in-apparatus temperature; a storing unit that stores a first positional shift amount corresponding to the in-apparatus temperature, the first positional shift amount indicating a predictive value for a positional shift of the toner image; a positional shift predicting correction controlling unit, when an absolute value of a variation of the measured in-apparatus temperature is smaller than a threshold temperature, controls to correct the positional shift based on the stored positional shift amount; a positional shift actual measurement correction controlling unit, when the absolute value of the variation of the measured in-apparatus temperature is equal to or greater than the threshold temperature, controls to correct the positional shift based on a second positional shift amount detected from a positional shift correction pattern which is formed by the image forming unit; and a modifying unit that modifies the first positional shift amount based on the second positional shift amount when a difference between the first positional shift amount and the second positional shift amount is equal to or greater than a threshold of a shift amount, wherein when the difference between the first positional shift amount and the second positional shift amount is smaller than the threshold of the shift amount, the threshold temperature is increased by a predetermined value, and the threshold temperature is a decision criterion for which one of the controls by the positional shift predicting correction controlling unit and the positional shift actual measurement correction controlling unit is performed.