Patent ID: 8867982

Claim:
An image forming apparatus, comprising: an image forming part that forms an image on an image bearing member; an intermediate transfer member onto which the image formed on the image bearing member is transferred; a transfer part that transfers the image formed on the intermediate transfer member onto a recording material; a conveying part that conveys the recording material; a detection part that detects the recording material which is conveyed by the conveying part; a reversing-conveying part that reverses the recording material on which an image is formed on a first surface of the recording material after the image is formed on the first surface of the recording material, and conveys the recording material to the transfer part again so as to form an image on a second surface of the recording material; and a control unit that controls timing for starting an image formation by the image forming part, wherein the control unit determines a size of the recording material in a direction in which the conveying part conveys the recording material based on information from a detection result of the detection part, wherein the control unit controls an operation of the image forming part so that, in a case where the size obtained by the control unit is the same as a designated size, an image formation on the second surface is started after a predetermined time lapses from a start timing when an image formation on the first surface of the recording material starts, and in a case where the size obtained by the control unit is larger than a designated size, an image formation on the second surface is started according to a timing of detection by the detection part when a trailing edge of the recording material that is conveyed and whose size is the larger, and without reference to the start timing of the image formation on the first surface, whereby an interval between an image to be formed on the first surface of the recording material and an image to be formed on the second surface of the recording material, on the intermediate transfer member in the case where the size obtained by the control unit is larger than the designated size, is larger than the interval in the case where the size obtained by the control unit is the same as the designated size.