The type of a document placed on the platen of an image forming apparatus is designated by the operator, a character area in the document is discriminated based upon an image signal obtained by reading the document, the orientation of the document is sensed based upon the discriminated character area and the type of document designated, and the image signal is processed based upon the sensed orientation of the document so as to obtain correctly oriented text at output of a prescribed image, such as a double-sided print image or layout of images of reduced size.