A gripper bar conveyor mechanism (34) for transferring sheets to be printed from one rotating impression cylinder (18) to another in a multiple color rotary offset printer of the type having sets of impression cylinders and corresponding blanket cylinders for rolling contact with the sheets to be printed therebetween is shown in figure 1. The gripper bar conveyor mechanism (34) includes a transferrable gripper bar (48) seen in detail in figure 2 is activatable for releasably securing sheets to be printed in a fixed orientation with respect to the transferrable gripper bar (48). The registration projection is affixed to the transferrable gripper bar. A registration pocket (88) shown in figure 5 is adjustably affixed to each of the impression cylinders (18, 52, 54, 56) for temporarily receiving the registration projection of the gripper bar and thereby holding the gripper bar (48) in a desired position with respect to the impression cylinder. A conveyor band (24) is attached to the gripper bar (48) and is operably connected to the rotary offset press (10) for moving the gripper bar (48) from one impression cylinder (18) to the next.