3. An image reading and/or reproducing apparatus, comprising: a single sided document feeding tray and a double sided document feeding tray to each supply a stack of documents to the apparatus; a document feeding unit to selectively feed a document from a top of the stack of documents in the single sided document feeding tray, or a document from a bottom of the stack of documents in the double sided document feeding tray; an image scan unit to scan an image of the document fed by the document feeding unit; a reverse unit to position the double-sided document, fed by the document feeding unit, upstream of the image scan unit as the image scan unit completes a scanning of the image on a first side of the document such that the image scan unit may scan the image on a second side of the document; a plurality of document convey paths to guide the documents fed from the document feeding unit to the image scan unit; a document discharge tray onto which fully scanned documents are discharged; an image scan path to guide the documents from the document convey path to the document discharge tray via the image scan unit; and a document reverse path to feed the document from the document reverse unit to the position upstream of the image scan unit; wherein the order of the documents when the documents were loaded into the double sided document feeding tray is retained when the documents are discharged from the apparatus, and the order of the documents when the documents were loaded into the single sided document feeding tray is reversed when the documents are discharged from the apparatus, and a first side of each document that is loaded face down into the double sided document feeding tray is also face down when the document is discharged from the apparatus; wherein each document in the stack of documents in the single-sided document feeding tray is loaded face up on the single-sided document feeding tray; wherein the reverse unit comprises: a discharge roller to selectively discharge a document to the document discharge tray or to reverse the document so as to convey the document along the document reverse path; a motor to drive the discharge roller; and a reverse sensor arranged between the discharge roller and the image scan unit to determine whether to drive the discharge roller so as to discharge the document or reverse the document, based on the presence of a document near the discharge roller.
3. An image reading and/or reproducing apparatus, comprising: a single sided document feeding tray and a double sided document feeding tray to each supply a stack of documents to the apparatus; a document feeding unit to selectively feed a document from a top of the stack of documents in the single sided document feeding tray, or a document from a bottom of the stack of documents in the double sided document feeding tray; an image scan unit to scan an image of the document fed by the document feeding unit; a reverse unit to position the double-sided document, fed by the document feeding unit, upstream of the image scan unit as the image scan unit completes a scanning of the image on a first side of the document such that the image scan unit may scan the image on a second side of the document; a plurality of document convey paths to guide the documents fed from the document feeding unit to the image scan unit; a document discharge tray onto which fully scanned documents are discharged; an image scan path to guide the documents from the document convey path to the document discharge tray via the image scan unit; and a document reverse path to feed the document from the document reverse unit to the position upstream of the image scan unit; wherein the order of the documents when the documents were loaded into the double sided document feeding tray is retained when the documents are discharged from the apparatus, and the order of the documents when the documents were loaded into the single sided document feeding tray is reversed when the documents are discharged from the apparatus, and a first side of each document that is loaded face down into the double sided document feeding tray is also face down when the document is discharged from the apparatus; wherein each document in the stack of documents in the single-sided document feeding tray is loaded face up on the single-sided document feeding tray; wherein the reverse unit comprises: a discharge roller to selectively discharge a document to the document discharge tray or to reverse the document so as to convey the document along the document reverse path; a motor to drive the discharge roller; and a reverse sensor arranged between the discharge roller and the image scan unit to determine whether to drive the discharge roller so as to discharge the document or reverse the document, based on the presence of a document near the discharge roller. 4. The apparatus of claim 3 , wherein, if the reverse sensor detects the presence of a double sided document, and the double sided document has previously been conveyed along the reverse path, the discharge roller discharges the double sided document to the document discharge tray.