device 38.
The paper with the toner image fixed thereon by the action of heat and pressure in the fixing device 38, is conveyed downward along the conveyance path that has been switched by the fixing/discharge rollers 61 and the switching means 62, is sequentially moved along the conveyance path formed toward the upper right direction by the conveyance rollers 600, 610 and 620, and thereafter reaches the ADU reversal rollers 800.
The ADU reversal rollers 800 are driven to rotate in the opposite direction at a timing at which the rear edge of the paper is nipped between the ADU reversal rollers 800 in the traveling direction. Therefore, the paper is reversed and conveyed on the conveyance path formed by the ADU 8, i.e., horizontally towards the right ofthe drawing at the conveying rollers 810 through 850, while the paper is conveyed in the opposite direction with its previous rear edge being as a new front edge. Thereafter, the paper is guided upward and sequentially arrive at the registration rollers 56 after passing through the conveying rollers 55, and a toner image is formed on the second side of the paper in the same process that has been described previously.
After the toner image on the second side of the paper is fixed by the fixing device 38, the paper is sequentially discharged onto the discharge tray 64 via the fixing/discharge rollers 61.
In this kind of image forming apparatus, a predetermined paper size (in particular, a length of paper in its travelling direction) is used as a