Patent ID: 8913292

Claim:
An image reading apparatus comprising: an image reading unit that reads, from a sheet being transported, an image printed onto the sheet, the image reading unit including a reference reflecting member that acts as a color reference, having at least a part thereof disposed at a location in proximity to the sheet being transported in the sheet width direction that intersects the sheet transport direction, an illuminating unit that illuminates the reference reflecting member and the sheet passing through, a line sensor that reads, from the sheet being transported, the image formed on the sheet, and in addition, reads the part of the reference reflecting member in proximity to the sheet in the sheet width direction, and a spectroscope which has a visual field encompassing a plurality of patches for correcting color tones formed on the sheet and arranged in the sheet transport direction, and which measures spectral distribution of each patch; and a computational unit that generates color tone correction data for correcting color tones by performing computations based on the spectral distribution of each patch measured by the spectroscope, and the read values of the reference reflecting member obtained by the line sensor, wherein the computational unit stores, in memory, reading results from the line sensor and measurement results from the spectroscope at timings that match each other, extracts the measurement results expressing the spectral distributions of the patches as measured by the spectroscope on the basis of the reading results from the line sensor at the matched timings, and uses the extracted spectral distributions to generate the color tone correction data.