Patent ID: 7835685

Claim:
An image forming apparatus comprising: a paper feeding device that feeds a transfer material; a length obtaining device that obtains a length in a feeding direction of the transfer material fed by said paper feeding device; a receiving device that receives image data; an image forming device that forms an image on a first side or a second side of the fed transfer material based on the image data received by said receiving device; an inversion device that feeds the transfer material having the image formed on its first side until a part of the transfer material gets exposed outside the image forming apparatus and then feeds the transfer material to a refeeding path in the image forming apparatus to invert the transfer material; a refeeding device that feeds the inverted transfer material to a standby position, at which a leading edge of the transfer material is stopped, the standby position indicating a position at which the transfer material is put on standby until a preparation for a next image forming process for the second side of the transfer material is completed; a determining device that determines whether or not the preparation for the next image forming process is completed; and a refeeding controlling device that, in the case where the preparation for the next image forming process is not completed, changes the standby position along the refeeding path so that the leading edge of the transfer material is stopped at different positions along the refeeding path depending on the length in the feeding direction of the transfer material obtained by said length obtaining device, wherein the standby position is set farther downstream as the length of the transfer material is longer; wherein said refeeding controlling device controls the transfer device not to stop at the standby position when said determining device determines that the preparation for forming the image on the second side of the transfer material is completed.