Document conveying device, and document conveying and reading apparatus

A document conveying device comprising:

• a sheet feeding tray on which a document is set;
• a sheet feeding unit which feeds the document set on the sheet feeding tray in a predetermined conveying direction;
• an actuator activated by the document set on the sheet feeding tray;
• a sensor which outputs a predetermined signal in response to an activation of the actuator;
• and
• a control part which receives the signal output from the sensor and controls the sheet feeding unit based on the signal, wherein
• the sheet feeding unit includes:
• a drive shaft rotatably supported above the sheet feeding tray;
• a holder whose upstream side end portion in the conveying direction is rotatably supported by the drive shaft and is turnable upward and downward together with the drive shaft;
• and
• a pickup roller which is rotatably supported at a downstream side end portion of the holder in the conveying direction and rotates in contact with the document set on the sheet feeding tray,
• the actuator includes:
• a rotational shaft rotatably supported above the sheet feeding tray;
• a detecting piece which is provided integrally with the rotational shaft, suspended from the rotational shaft by its own weight, and rotates the rotational shaft by being pushed by the document set on the sheet feeding tray;
• and
• a light-shielding piece which is provided integrally with the rotational shaft, suspended from the rotational shaft by its own weight, and switches an output of the sensor by the rotation of the rotational shaft, wherein
• when a signal different from a signal outputted from the sensor when the actuator is driven with the document set on the sheet feeding tray is input, the control part returns the sheet feeding unit to an initial posture in which the pickup roller is separated upward from the sheet feeding tray.