Bookbinding device and method

1. Field of the Invention A bookbinding device is disclosed to adhesively bind a back surface of a stack of pages to a center portion of a cover page, which includes a page supply unit (), a thickness sensor (), an adhesive applicator (), a page conveyor unit (), a cover supply unit (), a press unit () and a cover folding unit (). The cover supply unit includes a trimmer () for trimming a side edge portion of the cover sheet depending upon thickness of the page stack detected by the thickness sensor, and a positioning unit () for positioning the cover sheet such that a center line of the cover sheet which has been trimmed by the trimmer is aligned with a center of thickness of the page stack, at which position the page stack is adhesively bound to the cover sheet.