Image Forming Apparatus and Method of Controlling the Apparatus

摘要

Black tapes 61 and 62 having optical reflectances different from that of the texture of a document D are stuck to the lower side of a platen cover 3 . The black tapes 61 and 62 have the optical reflectances different from that of the texture of the document D. When the document D set on a document table 2 and the black tapes 61 and 62 are exposed by a light exposure lamp 5 , at least one edge of the document D set on the document table 2 and the length of the edge are detected according to the amount of reflected light from the document D and that from the black tapes 61 and 62 . The size of the document D set on the document table 2 is judged according to the detected length of the edge.