nt;FIG. 2 is a timing chart of the first embodiment;FIGS. 3A to 3C, when combined as shown in FIG. 3, show a constructional diagram of a color CCD linear image sensor according to the second embodiment;FIG. 4 is a timing chart of the second embodiment;FIGS. 5A to 5C, when combined as shown in FIG. 5, show a constructional diagram of a color CCD linear image sensor according to the third embodiment