A designating unit designates any of three edge faces other than an edge face corresponding to a spine of a book-bound article generated by a printer. A generating unit generates a bitmap corresponding to the designated edge face depending on a bookbinding condition. A rendering unit renders a first image designated by a user on the bitmap. A specifying unit specifies, among pieces of line data respectively corresponding to dots forming a first side parallel to a paper thickness direction and that each extend parallel to a second side orthogonal to the first side, in the bitmap, line data corresponding to an object page to be printed. An adding unit adds a second image to a place corresponding to the dots of the first image included in the specified line data, on a third side indicating a side of the object page corresponding to the specified line data.