wherein {HEAD ~ a rotational speed} of {TAIL ~ said first image bearing member} at said transfer position is different from that of said intermediate transfer member during the back transfer operation 
wherein { HEAD ~ a rotational speed } of { TAIL ~ said first image bearing member } at said transfer position is different from that of said intermediate transfer member during the back transfer operation
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH