Image reading apparatus

Abstract

An image reading apparatus includes: a shading roller that has a columnar shape extending in a longitudinal direction and is rotatable about a rotation axis extending in the longitudinal direction, the shading roller including, on an outer peripheral surface, a white reference arc surface which is white, has an arc-shaped cross section in a lateral direction, and extends in the longitudinal direction, and a white reference flat surface which is white, is a flat surface, and extends in the longitudinal direction; an image sensor array that is provided to oppose the shading roller across a transport path of a document, and includes a plurality of image sensors arranged in a main scanning direction and receiving reflected light of light emitted from a light source toward the document or the shading roller; and a processor, wherein the processor calculates difference data indicating a difference between arc surface read data, which indicates pixel values output from the image sensors, respectively, and obtained as the image sensor array receives the reflected light from the white reference arc surface, and flat surface read data, which indicates pixel values output from the image sensors, respectively, and obtained as the image sensor array receives the reflected light from the white reference flat surface, based on the arc surface read data and the flat surface read data, acquires corrected arc surface read data based on the arc surface read data and the difference data, corrects document read data, obtained as the image sensor array receives the reflected light from the document, based on the corrected arc surface read data to acquire corrected document read data, and forms image data corresponding to the document based on the corrected document read data.

Dependencies are inferred from the claim text.