Document conveying device

A document conveying device comprising:

• a sheet feeding tray on which a document is placed;
• a sheet feeding mechanism which feeds the sheet placed on the sheet feeding tray in a predetermined sheet feeding direction;
• a sheet feeding tray lifting mechanism which lifts and lowers the sheet feeding tray;
• a top plate which is adjacent to the sheet feeding tray on a downstream side in the sheet feeding direction and is in contact with a lower surface of the document to be fed;
• a fixed wall part which is provided extending downward from an upstream side end portion of the top plate in the sheet feeding direction and is fixed in position;
• a lifting wall part which is provided extending upward from a downstream side end portion of the sheet feeding tray in the sheet feeding direction, and lifted and lowered along the fixed wall part together with the sheet feeding tray;
• and
• a reflective optical sensor which detects the document placed on the sheet feeding tray, wherein
• the reflective optical sensor emits light in a direction inclined downstream of the sheet feeding direction from a vertically upward direction, and
• the document conveying device further comprises:
• a discharge tray which is provided below the sheet feeding tray and on which the document fed by the sheet feeding mechanism is discharged;
• a discharge document sensor which detects the document discharged on the discharge tray;
• and
• a control part which controls the sheet feeding tray lifting mechanism, wherein
• the control part drives the sheet feeding tray lifting mechanism when an output signal of either the reflective optical sensor or the discharge document sensor changes.