Patent ID: 6195179
Filing Date: 2001-02-27
Classification: H04N

Abstract:
An image reading device comprising:reading means capable of reading an original image through converting the original image into voltage data;reference voltage supply means capable of supplying a reference voltage;conversion means capable of receiving the voltage data and the reference voltage and converting the voltage data into numeric data with referring to the reference voltage;reference voltage setting means setting a value of the reference voltage to be supplied from the reference voltage supply means;memory means capable of storing a value of the set reference voltage; andimage reading control means for performing successively-executed image reading processes by repeatedly controlling the reading means to convert original images into voltage data, the reference voltage supply means to supply the reference voltage, and the conversion means to convert the voltage data into the numeric data with referring to the reference voltage, the image reading control means controlling the reference voltage setting means to perform a reference voltage setting operation to set the reference voltage to be used during one image reading process, by initially setting, as an initial value, a temporary reference voltage whose value is equal to the value of the reference voltage that is stored in the memory means and that is supplied from the reference voltage supply means during another image reading process which is performed before the subject image reading process, and by adjusting the thus initially-set temporary reference voltage value to determine the value of the reference voltage to be supplied from the reference voltage supply means during the subject image reading process.