Patent ID: 8896895
Filing Date: 2014-11-25
Classification: H04N

Abstract:
1. An image reading apparatus comprising: a light source which applies light to a target to be read; an image sensor which receives light reflected off the target to be read to read the target to be read; an analog processing portion which performs analog processing on an analog output of the image sensor; an A/D conversion portion which converts the analog output of the image sensor processed by the analog processing portion into digital image data; a light amount adjustment portion which performs light amount adjustment on the light source such that a maximum value of the analog output of the image sensor processed by the analog processing portion does not exceed an upper limit value of an input voltage range of the A/D conversion portion but approaches the upper limit value; a temperature sensor which measures a temperature around the image reading apparatus; and a storage portion which stores temperature data indicating the temperature around the image reading apparatus at a time of the light amount adjustment, wherein when an absolute value of a temperature difference between the temperature stored in the storage portion and a current temperature is less than a predetermined threshold value, the light amount adjustment portion does not perform the light amount adjustment whereas when the absolute value of the temperature difference between the temperature stored in the storage portion and the current temperature is equal to or more than the threshold value, the light amount adjustment portion performs the light amount adjustment.