CCD sensor output circuit of image reading apparatus

Claim 1

In an image reading apparatus having a CCD sensor for detecting light from a light source which are reflected by images, a CCD sensor output circuit which adjusts to changes in an output level of said CCD sensor, due to changes in a temperature of said light source, in accordance with the CCD sensor output of a reference region read by said CCD sensor, the improvement comprising: output adjusting means for detecting when said light source has been stabilized and adjusting the output level of said CCD sensor, in accordance with an output signal from said CCD sensor corresponding to said reference region, lighting control means for lighting said light source for a time period less than the length of a predetermined scanning time period in response to a lighting control signal, timing signal output means for outputting first timing signals for a first time period from the lighting of said light source until after said output adjusting means has detected that said light source has been stabilized, and second timing signals for a second time period beginning after said light source has been stabilized but prior to the output of the next said lighting control signal, and transfer control means, responsive to said timing signal output means, for transferring the output of said CCD sensor, which was accumulated in said CCD sensor after said first time period at said second time period, said output adjusting means adjusting said first time period for the output of said first timing signals or the width of said first timing signals so that the output level of said CCD sensor transferred at said second time period will be controlled to a given level.