| 摘要 |
PROBLEM TO BE SOLVED: To improve bit accuracy when repeatedly reading an image by changing the white monitor position referred to for performing white correction depending on the variation of light quantity in accordance with an original size when continuously reading with an ADF (automatic document feeder). SOLUTION: An image reader comprises a white reference plate for monitoring the variation of the light quantity, an original width detecting means, a means for deciding the detection point on the white reference plate for monitoring the variation of the light quantity determined by the original width detecting means, a means for storing the density data obtained by reading a white reference just before starting original reading, a means for determining a correction amount by a variation amount when the variation of the light quantity is detected, an AGC (automatic gain control), and a means for controlling the AGC in accordance with the correction amount. COPYRIGHT: (C)2004,JPO
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