Patent ID: 9628650
Date: 2017-04-18
CPC Classifications: H04N

Claim:
1. An image reading device comprising: a sheet conveying unit configured to convey an original in a sub-scanning direction; a reading unit configured to read information made up of pixels on a line-to-line basis at a reading position, the reading position being selected from a plurality of lines arranged in a prescribed range in the sub-scanning direction, each of the plurality of lines extending in a main scanning direction; a pressing member configured to press the original conveyed by the sheet conveying unit toward the reading unit; a drive unit configured to move the reading unit in the sub-scanning direction so that the reading unit is positioned at the reading position; a storing unit configured to store a plurality of defective positions; and a processor configured to: control the reading unit to read the pressing member to obtain one line worth of pixels at a position of selected one of the plurality of lines and detect whether there is a defective pixel in the one line worth of pixels; store a position of the detected defective pixel, as one of the plurality of defective positions, in the storing unit; set defective factors for respective normal positions, each of the normal positions being a position in the sub-scanning direction and indicating one of the plurality of lines having no defective pixel, wherein each of the defective factors is set to a function depending on a distance between the each of the normal positions and one defective position, which is from among the plurality of defective positions and is positioned within a specific range from the each of the normal positions, so that the closer the distance is, the larger the defective factor of the each of the normal positions is set; and set the reading position having a smallest defective factor from among the normal positions, wherein the reading unit reads the original conveyed by the sheet conveying unit at the set reading position.