Image reading apparatus and document supply device thereof

A document supply device of an image reading apparatus, comprising:

• a frame configured to have a document supply port and a document discharge port to discharge the document having passed a scanning window;
• a main feed path to guide a document introduced through the document supply port;
• a simplex path branched off the main feed path to guide the document from the main feed path to a scanning window to scan one surface of the document;
• a duplex path to guide the document having passed the scanning window to the simplex path to scan the other surface of the document;
• an auxiliary supply path branched off from the main feed path and connected to the simplex path configured to temporarily position the document fed through the main feed path before being fed through the simplex path to the scanning window, the auxiliary supply path including:
• an overturn path branched off from the main feed path and to guide the document so that upper and lower surfaces of the document are turned over, and
• an auxiliary feed path to guide the document fed to the overturn path to the simplex path and having an overturn roller to rotate in a forward direction and a reverse direction, the overturn roller to rotate in the forward direction to feed the document from the main feed path to the overturn path, and the overturn roller to rotate in the reverse direction to feed the document from the overturn path to the simplex path through the auxiliary feed path;
• and
• plural rollers to feed the document through the main feed path, the simplex path, the duplex path and the auxiliary supply path, the plural rollers including a discharge roller mounted at the frame near the document discharge port and capable of rotating in a forward direction and a reverse direction, such that when the discharge roller rotates in the forward direction, the document having passed the scanning window is fed to the document discharge port, and when the discharge roller rotates in the reverse direction, the document having passed the scanning window is fed to the duplex path.