Image reading method and image reading apparatus

A method comprising:

• a first step of returning a fed document to an upstream side of a reading unit by reversing the document after a first passage of the document through the reading unit;
• a second step of returning the document returned in the first step to the upstream side of the reading unit by reversing the document after a second passage of the document through the reading unit;
• and
• a third step of passing the document returned in the second step through the reading unit, and then discharging the document,
• wherein a first mode and a second mode are selectable,
• wherein, in the first mode, for a fed first document, an image is read from a first surface to store image data in a memory in the first step, and an image is read from a second surface, that is a back surface of the first surface, to store image data in the memory in the second step, while no image is read in the third step, and for a second document fed after the first document, no image is read in the first step, an image is read from the second surface to store image data in the memory in the second step, an image is read from the first surface to store image data in the memory in the third step, and then a plurality of image data stored in the memory is transmitted collectively, and
• wherein, in the second mode, for each of a plurality of fed documents, an image is read from the first surface to transmit image data in the first step, and an image is read from the second surface to transmit image data in the second step, while no image is read in the third step.

An apparatus comprising:

• a first path including a reading unit on a midway, through which a document passes;
• a second path disposed separately from the first path and configured to return the document passed through the reading unit of the first path to an upstream of the reading unit;
• and
• a control unit configured to perform control to execute a first step of passing a document through the reading unit and returning the document to an upstream of the reading unit,
• a second step of passing the document returned in the first step through the reading unit and returning the document to the upstream of the reading unit, and
• a third step of passing the document returned in the second step through the reading unit, and then discharging the document,
• wherein, in one of the first and third steps, the reading unit reads an image formed on a first surface of the document and, in the other of the first and third steps, the reading unit does not read the image formed on the first surface of the document,
• wherein, in the second step, the reading unit reads an image formed on a second surface of the document, wherein the second surface is a back surface of the first surface of the document, and
• wherein a speed of passage through the reading unit without reading the image in one of the first and third steps is higher than a speed of passage through the reading unit in the other of the first and third steps.

A method comprising:

• a first step of passing a document through a processing unit and returning the document to an upstream of the processing unit;
• a second step of passing the document returned in the first step through the processing unit and returning the document to the upstream of the processing unit;
• and
• a third step of passing the document returned in the second step through the processing unit, and then discharging the document,
• wherein, in one of the first and third steps, the processing unit processes an image formed on a first surface of the document, while the image is not process in the other of the first and third steps,
• wherein, in the second step, the processing unit processes an image formed on a second surface of the document, wherein the second surface is a back surface of the first surface of the document, and
• wherein a speed of passage through the processing unit without processing the image in one of the first and third steps is higher than a speed of passage through the processing unit in the other of the first and third steps.

An image reading apparatus comprising:

• a feed tray on which a document is stacked;
• an image reading unit configured to read an image of the document;
• a discharge tray on which the document is stacked after reading of the image:
• a conveyance path through which the document conveyed from the feed tray through the image reading unit to the discharge tray passes;
• a reversal conveyance path through which the document passing through the conveyance path on a downstream side of the image reading unit is reversed to be returned to the conveyance path on an upstream side of the image reading unit;
• and
• a document conveying mechanism configured to repeat, twice, an operation of returning the document fed from the feed tray and conveyed to the conveyance path on the downstream side of the image reading unit to the upstream side of the image reading unit via the reversal conveyance path, and conveying the document through the conveyance path again, to convey the document so that the same document passes through the image reading unit three times, and then to discharge the document to the discharge tray,
• wherein (i) a control operation to read images of both surfaces of the document by reading, while the document is conveyed by the document conveying mechanism to be discharged to the discharge tray, images of both surfaces of the document during first and second passage through the image reading unit, and (ii) a control operation to read images of both surfaces of the document by reading images of the document during second and third passage through the image reading unit, are alternately performed.

A method comprising:

• passing a first document through a reading unit to read a first surface of the first document;
• reversing the first document;
• passing the first document through the reading unit to read a second surface of the first document opposite to the first surface;
• reversing the first document;
• passing the first document through the reading unit without reading and discharging the first document;
• passing a second document through the reading unit without reading;
• reversing the second document;
• passing the second document through the reading unit to read a second surface of the second document opposite to the first surface of the second document;
• reversing the second document;
• and
• passing the second document through the reading unit to read the first surface of the second document and discharging the second document,
• wherein a speed of passage through the reading unit by the first and second document without reading is faster than a speed of passage through the reading unit while a reading is performed.