Patent ID: 8836967

Claim:
An image forming apparatus comprising: an image forming device; a sensor; a processor; and memory storing computer readable instructions that, when executed, cause the image forming apparatus to: acquire a plurality of factors that are causes of a deviation in image forming position; multiply the factors by coefficient defined in association with the factors, respectively; estimate amounts of the deviation resulting from the factors, respectively; determine whether a total of the estimated amounts of the deviation is equal to or larger than the reference value; in response to determining that the total of the estimated amounts is equal to or larger than the reference value, form a pattern on a member by the image forming device; detect a position of the pattern by the sensor; determine an actual deviation in the image forming position based on the detected position; compare the estimated deviation with the actual deviation; and alter at least the coefficient associated with the factor related to the estimated amount that is larger than the other estimated amounts more than the coefficient associated with the other factors.