Abstract: A plurality of spring bases 50, 51 and 52 are provided to a tail edge side clamping base 76 independently. A pair of base convexes 51T are formed on both an upper surface and a lower surface of the spring base 51. A tension selecting part 70 comprising a first block 72 having a pair of block convexes 72T is provided at a position confronted with the spring base 51. The block convexes 72T and the base convexes 51T are contacted with each other by moving a lever 72L formed on an upper surface of the first block 72 when the plate 15 is fitted tightly on a cylinder surface of a plate cylinder 60 with low tension. The lever 72L is moved either in a direction of the arrow 100 or 101 when the plate 15 is fitted tightly on the cylinder surface of the plate cylinder 60 with high tension.

Abstract: Shafts 7, a plate 6 and a guide plate 5 are moved so as to follow movement of both a stay 4 and a pushing member 3 by pushing force of coil springs 12 when the stay 4 and the pushing member 3 are moved toward a direction of an arrow 91 in accordance with rotation of pinion gears 15. The movement of both the plate 6 and the guide plate 5 is suspended when the shaft grips 7b are contacted to arms 13. Thereafter, only the stay 4 and the pushing part 3 are moved toward a direction of the arrow 91. So that, a tail edge side part 10b of the plate 10 is guided between the tail edge side clamp 23 and the tail side clamping base 24 along with the guide plate 5.