Color image reading device having an optical element for creating double images

A color image reading device for reading a document image, comprising:

• a line image sensor on which a document image is imaged, consisting of
• a first pixel line with pixels having a first reading spectral characteristic, and
• a second pixel line with pixels having a second and third reading spectral characteristics arranged alternately;
• an optical element provided on said line image sensor, said optical element generating separated double images, one of said double images being an optical image corresponding to said first reading spectral characteristic and the other of said double images being an optical image corresponding to the total of said second and third reading spectral characteristics;
• wherein
• the separation between the separated double images being generated by said optical element and imaged on said line image sensor being approximately equal to the distance between said two lines of pixels on said line image sensor.