US Patent 7362479 Image reading apparatus

The scanner comprises first and second sensors 21, 22 wherein light receiving elements with 600 dpi resolution are arranged, a first shift register 25 which outputs all the pixel signals received from light receiving elements in the first sensor 21, and a second shift register 26 which outputs pixel signals received from even numbered light receiving elements in the second sensor 22, and selectively executes quality oriented image reading with 300 dpi resolution by utilizing one pixel signal composed of added pixel signals received from two light receiving elements arranged next to each other, or speed oriented image reading with 300 dpi resolution by utilizing pixel signals received from the second shift register.