An image forming apparatus is equipped with a document reading device for reading image data on a document at a reading section; a memory to store the image data therein, the memory capable of storing the image data of plural pages of documents; and an image recording system for recording an image on a recording sheet based on the image data stored in the memory. A recording sheet reversing system receives the recording sheet from the image recording system, wherein the image is recorded on one side of the recording sheet, reverses the recording sheet, and refeeds the reversed recording sheet to the image recording system without stacking the recording sheet, whereby another image is recorded on the other side of the recording sheet by the image recording system. A controller controls the document reading device and the image recording system such that, when images are recorded on both sides of a recording sheet by the recording sheet reversing system, after image data of a predetermined number of pages of documents are read by the image recording system and are stored in the memory, the image recording system starts recording images based on the image data stored in the memory simultaneously as the document reading device successively reads other pages of documents.