Image reading apparatus, document detection method, and document reading method

A document detection method of detecting a document placed on a document table in an image reading apparatus including:

• the document table having a placement surface on which the document is placed;
• a reading unit configured to read, on a side opposite to the placement surface, the document placed on the placement surface of the document table;
• a light emitting unit capable of switching turn-on and turn-off and configured to illuminate the document from the side opposite to the placement surface of the document table in a turn-on state;
• and
• a document cover configured to open and close the placement surface of the document table
• the document detection method comprising:
• when it is determined, based on a result of executing first reading processing of, when the document cover is in an open state and before the document is placed on the placement surface, causing the reading unit to carry out reading in a state in which the light emitting unit is turned off, that the document placed on the placement surface can be detected, executing second reading processing of causing the reading unit to carry out reading in a state in which the document cover is in the open state and the light emitting unit is turned off;
• and
• detecting the document placed on the placement surface based on a difference between a result by the second reading processing and a result by the first reading processing.

A document reading method of reading a document placed on a document table in an image reading apparatus including:

• the document table having a placement surface on which the document is placed;
• a reading unit configured to read, on a side opposite to the placement surface, the document placed on the placement surface of the document table;
• a light emitting unit capable of switching turn-on and turn-off and configured to illuminate the document from the side opposite to the placement surface of the document table in a turn-on state;
• and
• a document cover configured to open and close the placement surface of the document table,
• the document detection method comprising:
• when it is determined, based on a result of executing first reading processing of, when the document cover is in an open state and before the document is placed on the placement surface, causing the reading unit to carry out reading in a state in which the light emitting unit is turned off, that the document placed on the placement surface can be detected, executing second reading processing of causing the reading unit to carry out reading in a state in which the document cover is in the open state and the light emitting unit is turned off;
• detecting, based on a difference between a result by the second reading processing and a result by the first reading processing, that the document was placed on the placement surface;
• and
• executing, based on a result of detecting that the document was placed on the placement surface, document reading processing of causing the reading unit to read the document.