Patent ID: 8098410
Filing Date: 2012-01-17
Classification: H04N

Abstract:
1. An image reading apparatus comprising: a scanner unit configured to scan an original and acquire image data; an original tray for stacking a pile of originals; a feeding control unit that controls feeding of originals from the original tray to a scanning position, the control of feeding of original including a sheet-through operation in which originals are fed continuously one by one from the original tray to a scanning position; a scanning control unit that causes the scanner unit to be fixed at the scanning position so as to scan originals that pass over the scanning position when the originals are fed from the original tray; a white plate provided in a position different from the scanning position; a shading operation unit that performs a shading operation, the shading operation including moving the scanner unit to the position of the white plate, and scanning the white plate to acquire white data to be used in performing shading correction on image data acquired by the scanner unit; and a measuring unit that performs a light-quantity measuring operation, the light-quantity measuring operation including causing the scanner unit to measure a light quantity of an exposure lamp that illuminates the original at the scanning position, wherein when a pile of originals is placed on the original tray, the feeding control unit performs the sheet-through operation, when one original is fed from the original tray to the scanning position, the shading operation unit performs the shading operation to acquire current white data, the measuring unit performs the light-quantity measuring operation to acquire a current light quantity of the exposure lamp as a reference value, when a subsequent original is fed from the original tray to the scanning position, the measuring unit performs the light-quantity measuring operation to acquire a current light quantity of the exposure lamp as a subsequent light quantity, and when an amount of change between the reference value and the subsequent light quantity is out of a predetermined range, the shading operation unit performs the shading operation to acquire new white data and updates existing white data with the new white data, the measuring unit performs the light-quantity measuring operation to acquire a new light quantity and updates an existing light quantity with the new light quantity, and the feeding control unit does not stop the sheet-through operation when the shading operation unit is not to perform the shading operation, and the feeding control unit stops the sheet-through operation when the shading operation unit is to perform the shading operation.