Patent ID: 7535603

Claim:
An image reading apparatus that scans an image from an original document, comprising: a light source that irradiates a light to the original document; a photoelectric conversion element that selectively receives a red color component, a green color component, and a blue color component of a light which is reflected from or transmitted through the original document so as to accumulate electric charge, the amount of which depends on the amount of the light received; a driving mechanism that moves either one of the photoelectric conversion element or the original document in a predetermined direction with respect to the other; a detection sensor that detects a vector amount of movement of either one of the photoelectric conversion element or the original document in the predetermined direction with respect to the other so as to output a detection signal for each vector amount of movement that corresponds to a minimum unit of a reading area of the image; and a control section that executes one cycle of operations each time when the detection signal is outputted from the detection sensor, where said one cycle of operations consists of a light reception operation in which the photoelectric conversion element receives a light of each color component in a predetermined color order for a predetermined light reception time duration at a predetermined time interval in such a manner that the light reception operation is executed once for each color component, and an electric charge discharge operation in which electric charge is taken out of the photoelectric conversion element after each light reception operation executed for the predetermined light reception time duration, wherein the control section selects and executes either one of a first control and a second control based on a predetermined condition information, where, in the first control, the electric charge of the photoelectric conversion element is discarded during a time period in each cycle after the electric charge discharge operation for the last color component but before the outputting of the detection signal, whereas such a discarding operation is not executed in the second control.