Patent ID: 7570897

Claim:
An image forming apparatus comprising: an image forming section for carrying out image formation on recording paper; a duplex conveying section for refeeding to said image forming section the recording paper having its first side undergo the image formation to perform image formation on a second side of the recording paper; an ejecting section to which the recording paper after the image formation is ejected; a detecting section for detecting the size of the recording paper; and a control section for controlling image formation, when performing image formation on both sides of a plurality of recording papers, so as to undergo the image formation on the first side of a second recording paper fed after a first recording paper prior to the image formation on the second side of the first recording paper by the image forming section, wherein the control section controls, when an error occurs indicating the length of the second recording paper is different from a predetermined length, so as to reverse the second recording paper through the duplex conveying section irrespective of the length of the second recording paper to perform image formation on the second side of the first recording paper by the image forming section, and to eject the second recording paper from the ejecting section after the first recording paper without performing the image formation.