Patent ID: 6943922

Claim:
An image reading apparatus for reading lines to be read on a surface of an original document in a sub-scanning direction and outputting image signals obtained by reading said lines to be read, comprising: a reading unit having light sensing devices that are able to simultaneously read M (said M is a natural number being not less than two) pieces of lines to be read which are said lines to be read existing on said surface of said original document and which are different lines in said sub-scanning direction, each existing apart by N (said N is a natural number being not less than two) pieces of lines in said sub-scanning direction; a moving unit to move one of said original document and said reading unit, every time said lines are simultaneously read, by L (said L is a natural number) pieces of said lines to be read, in said sub-scanning direction; and an image signal outputting unit to output said image signals of said lines to be read which have been read by said reading unit in order of reading in said sub-scanning direction; wherein values of said M, said N, and said L are set to values at which lines on said surface of said original document are able to be read without omission of reading lines when simultaneous and sequential reading operations are performed from a first line to be read to a last line to be read on said surface of said original document; and wherein values of said M, said N, and said L are set so that M≧2, N>1+M, and L=N−1.