Patent ID: 8482824
Filing Date: 2013-07-09
Classification: H04N

Abstract:
1. An image reading apparatus comprising: a sheet table comprising a placement surface on which a sheet is placed; a light emitting device comprising a plurality of light sources, each of which emits different color light from one another; a light emitting unit, which comprises a plurality of light emitting devices, and which emits light to the placement surface; a light receiving unit that receives reflected light from the placement surface; a read image conversion unit that converts the reflected light into read image information; a pulse signal output unit that outputs a pulse signal of a period corresponding to a time for converting into the read image information of one line as a minimum unit for converting into the read image information by the read image conversion unit from the reflected light of each of the plurality of light sources; a plurality of drive current supply units that supply drive currents, each of which is a constant current, to respective one of the plurality of light emitting devices; a light emission control unit that is configured to: a first light emission parameter determination unit that is configured to: a second light emission parameter determination unit that determines a drive current value of a second light emitting device and the light emission time of each of the plurality of light sources of the second light emitting device such that a sum of a first light amount and a second light amount becomes the light amount required for converting into the read image information during the period, wherein: wherein the light emission control unit controls the plurality of light sources to emit the same color light in sequence based on the drive current value of each of the first light emitting device and the second light emitting device and the light emission time of each of the plurality of light sources determined by the first light emission parameter determination unit and the second light emission parameter determination unit.