To provide an image forming device achieving energy saving while preventing the jamming of recording paper due to its curling and wasteful power consumption.

The image forming device comprises, at least, a charging means for charging the surface of a photoreceptor, an exposing means for forming an electrostatic latent image in accordance with image data, a developing means for developing the electrostatic latent image to form a toner image, a transfer pole for transferring the toner image to the recording paper, a separation pole for electrostatically separating the recording paper from the photoreceptor, and a fixing means for fixing the toner image on the recording paper. It also has a curl detecting means for detecting the size of the curl of the recording paper before carried to the transfer pole, a belt member arranged between the separation pole and the fixing means for carrying the recording paper and having a plurality of through-holes, a suction means for sucking the recording paper to the belt member through the through-holes, and a control means for controlling the suction force of the suction means to be changed corresponding to the size of the curl detected by the curl detecting means.