Patent ID: 7995250
Filing Date: 2011-08-09
Classification: H04N

Abstract:
1. An image-reading device that reads an image of an original document line by line, each line image extending in a main scanning direction, the image reading device comprising: an image sensor having a plurality of photodetectors arranged linearly in the main scanning direction; a clock generator that generates clocks having a clock speed; a resolution setting unit that sets a resolution of the image sensor in the main scanning direction, the image sensor being configured to output an image signal of the read image of the original document at the resolution set by the resolution setting unit; a border pixel determiner configured to determine that one of the plurality of photodetectors has read a border pixel, the border pixel being one of a plurality of pixels in a line image of the original document, the line image including a first plurality of pixels, a second plurality of pixels, wherein the border pixel is positioned between the first plurality of pixels and the second plurality of pixels; and a resolution switching unit that switches, during reading one line image extending in the main scanning direction, the resolution set by the resolution setting unit from a first resolution to a second resolution different from the first resolution when the border pixel determiner determines that one of the plurality of photodetectors has read the borderpixel, such that the image sensor outputs the image signal corresponding to the first plurality of pixels of the one line image at the first resolution and outputs the image signal corresponding to the second plurality of pixels of the one line image at the second resolution.