Patent ID: 6819799
Filing Date: 2004-11-16
Classification: G03B,H04N

Abstract:
An image reading apparatus comprising:a light source for illuminating the light on an original to be read having a plurality of images recorded thereon; conveyance means for conveying said original to be read in such a manner that each of said plurality of images passes through a predetermined reading position sequentially; image-forming means for focusing the light transmitted through said original to be read or the light reflected from said original to be read; an image sensor for separating each of said plurality of images recorded on said original to be read into a plurality of pixels, reading said pixels and outputting said pixels as image data; moving means for moving at least one of at least one portion of said image-forming means, said image sensor, and said original to be read along the optical axis direction of said image-forming means; storage means for storing a first value of a focusing point for each of a plurality of optical magnifications and for storing at least one of at least one second value, which is obtained by controlling said moving means in such a manner as to control the focusing for at least one predetermined optical magnification of said plurality of said optical magnifications for an object located at said reading position, and a difference of said second value and said first value at the predetermined optical magnification with respect to said second value, said first value being obtained by controlling said moving means in such a manner as to control the focusing to attain a coincidence between the image-forming position of a reference object which image-forming position depends on said image-forming means and the position of said image sensor for each of said plurality of optical magnifications; and control means for controlling said moving means in such a manner that at least one of at least one portion of said image-forming means, said image sensor and said original to be read moves to a position based on said first value and on one of said difference and said second value, which are stored in said storage means, at the time of reading one of a portion and the whole of said plurality of images.