Image unit with guide unit movable in direction perpendicular to conveyance path

A medium conveyance apparatus comprising:

• a first unit fixed on one side of a conveyance path of a sheet-shaped medium;
• a second unit provided on the other side of the conveyance path and facing the first unit;
• a guide unit provided at the second unit and contacting the medium inserted into a gap between the first unit and the second unit to move the second unit in a direction away from the conveyance path;
• an imaging unit provided at one of the first unit and the second unit;
• a reference plate, an image of which can be captured by the imaging unit, and provided at the other one of the first unit and the second unit;
• and
• a detecting unit for detecting the medium conveyed in the conveyance path, and provided in the conveyance path at an upstream position of a reading position where the imaging unit reads the medium, with respect to the conveyance path, wherein
• the guide unit includes a path surface in a first plane parallel to a second plane of a surface of the second unit facing the first unit and the conveyance path, wherein
• the detecting unit is provided at an upstream edge of the path surface of the guide unit with respect to the conveyance path so that the detecting unit detects the medium before the medium reaches the path surface of the guide unit, and wherein detecting unit detects a leading end of the medium and causes the imaging unit to capture the image of the reference plate responsive to said detection of the leading end, and
• wherein the guide unit includes a hole in the first plane where a detection portion of the detecting unit is inserted therein for detecting the medium conveyed in the conveyance path.