PURPOSE: To eliminate printing hindrance such as shock-streak and doubling, in a printing cylinder where printing devices such as a form plate and a blanket are mounted in gaps formed at a plate cylinder, a blanket cylinder and so on, by charging a buffering member into a clearance in the circumferential direction after mounting the printing devices in the gaps.

CONSTITUTION: At the ends of the gripper side 8a and the gripper end side 8b of a blanket 8k metallic fittings 9a, 9b are fixed. The metallic fitting 9a on the gripper side is inserted in a gripper 21a and the metallic fitting 9b on the gripper end side in the groove 26b of a tension bar 26, so that it is included by the rotation of the tension bar 26 and the blanket 8 is mounted onto a blanket cylinder 21. At the position of a gap 22, a clearance is generated along the circumferential direction of the blanket cylinder 21 between the grippers 8a, 8a. A buffering member (shock buster) 31 is inserted in the clearance so that the clearance may become zero. No printing pressure change occurs at the clearance, so it is possible to eliminate printing hindrance such as shock- streak and doubling.