a document holding fixture for a vertical optical scanner . the fixture has a main body , a transparent panel , four linking bars , a document cover panel , and a document backing plate . the document holding fixture uses a simple four linking bar system to maintain a constant parallelism between the document cover panel and the surface of the transparent panel . weight of the document cover panel provides necessary pressure to press a scan document firmly onto the glass surface of the transparent panel . to facilitate single hand document insertion , a stationing device is used to freeze the document cover panel when the panel reaches a horizontal position .