Abstract: A contact image sensor is provided with a modified photodevice module and method of operation. The photodevice modules convert the video signals created by the sensed lights from an electrical charge to electrical voltage immediately upon stimulation of the photodevice, and hold the electrical voltage at another element in the photodevice module so that the voltage can be immediately output when the shift register output switch is turned on. A dark current elimination circuit is also provided and includes a light-shielded photodevice which produces a dark current reference signal representative of the expected dark current in the photodevices of the photodevice modules. This dark current reference signal is used to adjust the electrical charge created by the light stimulation of the photodevice.