Patent ID: 6175649
Filing Date: 2001-01-16
Classification: H04N

Abstract:
An image scanning apparatus for optically scanning images of a plurality of originals set on an original tray, said image scanning apparatus comprising:a light source which illuminates each said original;a lens which condenses light from said each original to condensed light;a linear image sensor, arranged at a position of concentration of said condensed light, said linear image sensor comprising a plurality of light-receiving elements arrayed in a primary scanning direction for converting light to electrical signals;a scanning range setting unit which sets a plurality of scanning ranges of said linear image sensor in said primary scanning direction, each of said scanning ranges including at least one of said plurality of originals, at least one of said scanning ranges including at least two of said plurality of originals;an optical system shifting unit which adjusts relative positions of said lens, said linear image sensor and said original tray in order to sequentially realize said plurality of scanning ranges set by said scanning range setting unit;a color reference data generating unit which obtains, for each said scanning range, an output signal of said linear image sensor for a preset color reference and which generates respective color reference data for each said scanning range for correcting sensitivity of each light-receiving element of said linear image sensor on the basis of said output signal;a secondary scanning unit which moves said original tray relative to said linear image sensor in a secondary scanning direction while the scanning range of said linear image sensor is fixed; andan electrical signal correction unit which corrects an electrical signal which is output from said linear image sensor while said original tray is moving in said secondary scanning direction, as a function of said color reference data.