Image reader

Abstract

To locate a scanning unit at a home position with a simple configuration.SOLUTION: An outer edge member 18 arranged on an outer edge of a platen glass 16 has a first reference surface 18a that forms an undersurface of an area along a side edge part forming one end in a main scanning direction of the platen glass 16 and a second reference surface 18b that is adjacent to the first reference surface 18a and different in light reflectance from the first reference surface 18a. An image processing section 5c determines whether outer edge pixel data of an outer edge area in pieces of line image data sequentially obtained while a scanning unit 1x moves satisfies a boundary condition. Unit driving sections 17, 5b move the scanning unit 1x by a predetermined distance with the position of the scanning unit when the outer edge pixel data is determined to satisfy the boundary condition as a starting point and then stop the scanning unit, thereby locating the scanning unit 1x at a home position.SELECTED DRAWING: Figure 5

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