Patent ID: 7800792

Claim:
An image reading method for reading an image on a document, comprising: cyclically reading the image in a main scanning direction by using an image pickup section, while relatively moving at least one of a light emitting section and the document irradiated by the light emitting section with a sub-scanning velocity in a sub-scanning direction perpendicular to the main scanning direction, with respect to the image pickup section which comprises a plurality of light receiving elements arranged in the main scanning direction; controlling, while performing the cyclic reading, a reading cycle in the main scanning direction to be inversely proportional to a magnification ratio, wherein the reading cycle is a time period within which the plurality of light receiving elements read one main scanning line of the image in the main scanning direction; controlling, while performing the cyclic reading, a light emitting intensity and a light emitting period of the light emitting section in the reading cycle to be constant irrespective of the magnification ratio; and controlling, while performing the cyclic reading, the sub-scanning velocity to be constant irrespective of the magnification ratio.