Patent ID: 9075376
Filing Date: 2015-07-07
Classification: G03G

Abstract:
1. An automatic document feeder that conveys original document sheets placed on a document tray unit one sheet by one sheet on power from a driving motor, the automatic document feeder comprising: a sheet-feed cover unit configured to be operable to be opened and closed to allow removal of a jammed document at an occurrence of document jam; a switch unit configured to include a first terminal, to which a first voltage, by which the driving motor is driven, is input, and a second terminal connected to the driving motor, the first terminal and the second terminal being switched on when the sheet-feed cover unit is in a closed state, and the terminals being switched off when the sheet-feed cover unit is in an open state; and an open/close-detection circuit unit configured to detect whether the sheet-feed cover unit is in the open state or in the closed state, wherein the open/close-detection circuit unit includes the first switch circuit is switched on or off based on a threshold voltage that is larger than a second voltage to be generated in the driving motor by a motion of removing the jammed document and smaller than the first voltage, and the open/close-detection circuit unit detects that the sheet-feed cover unit is in the closed state when the second switch circuit is on, and detects that the sheet-feed cover unit is in the open state when the second switch circuit is off.