An image forming apparatus includes a reversing unit for reversing a two-sided document and placing the document on a platen, a reading unit for reading image data of either a front or back side of the document placed on the platen by the reversing unit, and at least one of: (i) a first detecting/setting unit for providing first information representing a position on which a binding margin of the document is located and a direction in which a top or bottom portion of the document is directed, and (ii) a second detecting/setting unit for providing second information representing a position on which a binding margin of an image to be printed is located and a direction in which a top or bottom portion of the image to be printed is directed. An image converting unit is provided for converting the read image data into output image data according to at least one of: (i) the first information with respect to the position of the binding margin of the document and the direction of the document, and (ii) the second information with respect to the position of the binding margin of the image to be printed and the direction of the image to be printed. And a writing unit is provided for printing the image to be printed according to the output image data.