A four-line CCD sensor is structured by line sensors R, G, B in which color filters are respectively disposed on surfaces of light receiving elements, and a line sensor BK at which no color filter is disposed. Amplitudes of signals which are outputted from the line sensors R, G, B at a time of reading...http://www.google.com/patents/US6958835?utm_source=gb-gplus-sharePatent US6958835 - Image inputting apparatus and image forming apparatus using four-line CCD sensor
