JP2008252320A5 - - Google Patents

Claims (5)

An image reading device that emits light from a plurality of light sources having different emission colors, irradiates light on a document, and photoelectrically converts the reflected light of the light by an image sensor, thereby generating image data of the document,
Instruction means for instructing the image sensor to sweep out the accumulated charge obtained by photoelectric conversion;
A memory for storing image data obtained by converting an analog value representing the amount of accumulated charge swept out in accordance with an instruction from the instruction means into digital data by A / D conversion;
Transfer means for transferring image data stored in the memory to an external device;
And control means for controlling a pre-Symbol plurality of light sources each emitting,
The control unit performs control so that none of the plurality of light sources emits light during a period in which the image data stored in the memory is transferred to the external device by the transfer unit.
Image reading device comprising a call.   A counter that counts the number of times that the synchronization signal for instructing the discharge of accumulated charges by the instruction means is supplied;
  For each of the plurality of light sources, it further comprises holding means for holding light emission information indicating when the value of the counter emits light.
  The control means controls light emission of each of the plurality of light sources based on the value of the counter and the light emission information.
  The image reading apparatus according to claim 1. The counter is configured to be reset when a value of the counter reaches a predetermined first value;
The light emission information is information on a predetermined number of bits for each of the plurality of light sources, and each bit has information associated with a different value of the counter,
Wherein, for each of the plurality of light sources, the image reading apparatus according to claim 2, characterized in that to control the light emission in accordance with the value of the bit associated with the value of the counter in the light emitting information. The plurality of light sources includes light sources of three kinds of emission colors,
The counter is configured to be reset every time the synchronization signal is supplied four times .
The control means causes the light sources of the three kinds of light emission colors to emit light sequentially when the number of times counted by the counter is 1 to 3, and emits the three kinds of light emission when the number of times counted by the counter is reset. The image reading apparatus according to claim 2 , wherein the image data stored in the memory is transferred by the transfer unit without causing any of the color light sources to emit light . The image reading apparatus according to claim 4 , wherein the light sources of the three kinds of light emission colors are red, green, and blue light sources.