Abstract: An optional cassette can be used for a electrophotographic process engine which occupies a minimum installation space and provides easy removal of jammed paper. A lower surface of the electrophotographic process engine is joined in steps with an upper surface of the optional cassette, and the the electrophotographic process engine comprises a second paper cassette and a second transmission passage formed vertically to a pull of paper in the second paper cassette. The optional cassette comprises an optional cassette module having a paper cassette slot for inserting a first paper cassette, and a pick up roller for picking up a paper form an uppermost paper of a paper pile in a position near the paper cassette slot and in the upper side of the option cassette module.