Patent ID: 7236265
Filing Date: 2007-06-26
Classification: H04N

Abstract:
1. An image reading apparatus comprising: an imaging unit having a plurality of channels, comprising photo-receiving sections and light-shielding sections, said imaging unit outputting effective signals from said photo-receiving sections and outputting optical black signals from said light-shielding sections; a signal correction unit which corrects the effective signals for the channels; and a controller which reads output optical black signals from said light-shielding sections at first and second times and controls said imaging unit to output, with predetermined timing, the signals for correction by said signal correcting unit, wherein the predetermined timing is the time that a predetermined value is reached by a level difference for each of the channels between a first optical black signal output for each of the channels from said light-shielding section at the first time and a second optical black signal for each of the channels from said light-shielding section at the second time output after the first optical black signal is output.