Patent ID: 7969620

Claim:
An image reader comprising: an image sensor comprising a plurality of light receiving elements arranged in a main scanning direction, wherein the plurality of light receiving elements receive a reflection light from a document and perform a photoelectric conversion to convert the reflection light into a plurality of image signals; a Modulation Transfer Function (MTF) calculation portion which calculates an MTF of the image sensor based on image data which is obtained by reading a predetermined MTF detection pattern by the image sensor; and an image processing portion which, based on the MTF calculated by the MTF calculation portion, divides the plurality of light receiving elements into a first MTF region in which the MTF of the light receiving elements positioned in the first MTF region is greater than a first predetermined MTF value and a second MTF region in which the MTF of the light receiving elements positioned in the second region is less than a second predetermined MTF value, and performs a first image process on the plurality of image signals which are outputted from the light receiving elements in the first MTF region and a second image process on the plurality of image signals which are outputted from the light receiving elements in the second MTF region.