| 摘要 |
An image reader for digitally reading an image on an original document by causing at least two aligned CCDs to commonly read an overlapping portion of the image which corresponds to a joint portion of the CCDs and by cancelling pixel data read by one of the CCDs. A first CCD is mounted on a base plate. A second CCD is fixed in place on one or free end portion of a support plate the other end of which is rigidly connected to the base plate. The base plate and the support plate are different from each other in the coefficient of thermal expansion. In order to compensate for a change in the ratio of an overlapping portion of the image due to an expansion or a contraction of the base plate which is caused by a temperature variation, a predetermined relationship is set up between the positions of the first and second CCDs and that of the support plate relative to the base plate and the coefficients of thermal expansion of the base plate and support plate. Temperatures of the base plate are sensed so that an expansion or a contraction of the base plate is computed based on the sensed temperature, thereby determining a deviation of the overlapping portion. Data outputted by the CCDs are processed in response to the determined deviation.
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