A tandem type color image forming machine includes a plurality of image forming units, a primary transfer belt, and a paper feed cassette in its image forming machine body. The paper feed cassette is arranged longitudinally in the lateral direction of the belt mechanism or below the belt mechanism. In addition, the machine includes a secondary transfer unit for transferring toner images from the primary transfer belt to a paper fed from the paper feed cassette. The machine also includes a paper feed conveyor passage for guiding paper, a fixing unit downstream of the paper feed conveyor passage, a pair of discharge rollers and a paper discharge passage formed between the fixing unit and the pair of discharge rollers. Further, the machine has a pocket for receiving and storing paper discharged from the pair of discharge rollers.