IMAGE READER AND ITS METHOD

摘要

PROBLEM TO BE SOLVED: To provide an image reader that cancels a noise of a digital signal processing system superimposed on a valid part of an analog signal so as to read an image with high accuracy. SOLUTION: The image reader superimposes data of a digital system and a fixed noise of a data clock system onto a sensor output signal 33 even at acquisition of reference data and outputs a data output by canceling the fixed data at the output of image read data. In this case, a number of image read data may largely be different from the number of data at acquisition of the reference data depending on the resolution. In order to avoid mismatching between a dummy clock output timing at the acquisition of reference data and a data output timing at image reading, the number of data output terminals is selected to select and set a proper timing for each resolution to match the clock output timing at the reference data acquisition with the data and clock output timing at reading the image.