Patent attributes
There is provided an image reading device, which comprises a photoreceptor unit having photoreceptors aligned in a line, and a signal output unit having output channels from which output signals of the photoreceptors are outputted. The output channels respectively correspond to regions into which the photoreceptors are divided. The image reading device further comprises an amplifier unit to amplify the output signals from the output channels, and a gain adjustment unit configured to use a maximum level of white signals outputted by the signal output unit as the output signals when the photoreceptor unit receives light from a white object to adjust a gain of amplification of the amplifier unit with respect to the output signals belonging to at least one of the regions other than a first region to which an output signal corresponding to the maximum level belongs.