Patent ID: 8295420

Claim:
An image reading device, comprising: a photoelectric conversion device that outputs an analog signal corresponding to an image read from a document; an A-D converter that converts the analog signal outputted by the photoelectric conversion device into a digital signal; a spread spectrum clock generation unit configured to generate a spread spectrum clock by executing frequency-modulation on a reference clock having a constant frequency; an acquisition timing setting unit configured to set an acquiring timing of the analog signal to be converted into the digital signal, with reference to the spread spectrum clock generated by the spread spectrum clock generation unit; and an acquisition timing correction unit configured to execute a delay correction for the acquiring timing of the analog signal set by the acquisition timing setting unit in accordance with a frequency of the spread spectrum clock defined when the analog signal is outputted, wherein the analog signal acquired at the corrected acquiring timing corrected by the acquisition timing correction unit is converted into the digital signal by the A-D converter.