Color copying machine

DETAILED DESCRIPTION It is therefore an object of this invention to provide a color copying machine capable of suitably varying the time required for the copying depending on the size of a record sheet of paper.
According to the present invention, there is provided a color copying machine which comprises a color copying machine comprising scanning means for applying illumination onto a color original to effect a scanning operation; a photoconductive drum operable to rotate at a constant speed; means for charging the photoconductive drum; color separating means including a plurality of optical filters of different colors, each of the filters allowing a predetermined light component of the illumination to pass therethrough during each scanning operation so as to apply it onto the photoconductive drum to form an electrostatic image thereon; developing means for applying toner to the electrostatic image during the rotation of the photoconductive drum to form a toner image; a transfer drum rotatable at a variable speed, the transfer drum being adapted to hold a record sheet therearound, the toner image on the photoconductive drum being sequentially transferred to the record sheet to form a color image on the record sheet; first sensor means for sensing the initiation of each scanning operation to feed a first sensing signal; second sensor means for sensing the position of the record sheet on the transfer drum to feed a second sensing signal; and control means responsive to the first and second sensing signals for detecting start and end timings of the transfer operation and for controlling the transfer drum to rotate at the same speed as the photoconductive drum during the transfer process, the control means controlling the transfer drum to rotate during a time interval between the two consecutive transfer operations at such a speed that a leading edge of the record sheet on the transfer drum is brought into agreement with a leading edge of the original image on the photoconductive drum.