Automatic skew adjusting apparatus,imaging apparatus and automatic skew adjusting method

A skew adjusting apparatus is provided for an image forming apparatus having a plurality of skew adjusting parts (130) arranged in a plurality of laser scanning units (111), respectively. The automatic skew adjusting apparatus comprises a driving source (120), an actuating part (140) arranged on a driving shaft (123) of the driving source (120) so that the actuating part (140) can be selectively connected with one of the skew adjusting parts (130) depending on a position of the driving source (120). The actuating part (140) actuates the connected skew adjusting part (130) as the driving shaft (123) rotates. A positioning part (170) moves the driving source (120) and a power transmission part (150) transmits or cuts off the power of the driving source (120) to the positioning part (170) so as to move the driving source (120) or stop the movement of the driving source (120).