Printing plate mounting apparatus

1. A printing plate mounting apparatus for mounting a printing plate peripherally of a plate cylinder, comprising:

a forward-end clamping jaw disposed peripherally of said plate cylinder for pinching a forward end of said printing plate with a clamping base;

a forward-end clamping jaw switching means disposed on one end surface of said plate cylinder for opening and closing said forward-end clamping jaw;

a plurality of rear-end clamping jaws disposed peripherally of said plate cylinder for pinching a rear end of said printing plate with a clamping base;

a rear-end clamping jaw switching means disposed on one end surface of said plate cylinder for opening and closing said plurality of rear-end clamping jaws together, and

straining means disposed on said plate cylinder for moving said rear-end clamping jaws in a direction for straining the printing plate pinched.

2. A printing plate mounting apparatus as defined in claim 1 , wherein said straining means further strain the printing plate pinched by said forward-end clamping jaw and said rear-end clamping jaws, by rotating one of said forward-end clamping jaw and said rear-end clamping jaws with the clamping base.

3. A printing plate mounting apparatus as defined in claim 2 , wherein said plate cylinder is an n-segmented cylinder, where n is an integer 2 or more, for supporting printing plates n in number, said forward-end clamping jaw, said forward-end clamping jaw switching means, said rear-end clamping jaws, said rear-end clamping jaw switching means and said straining means, respectively, are n in number and arranged equidistantly.

4. A printing plate mounting apparatus as defined in claim 1 , wherein said forward-end clamping jaw switching means and said rear-end clamping jaw switching means include air cylinders, respectively, said air cylinders being connected to an air source disposed outwardly of said plate cylinder, through a rotary joint disposed axially of said plate cylinder.

5. A printing plate mounting apparatus as defined in claim 4 , further comprising mechanical valves each disposed between one of said air cylinders and said rotary joint to be rotatable with said plate cylinder and contacting a contact member disposed outwardly of said plate cylinder to vary air supply to said one of said air cylinders.

6. A printing plate mounting apparatus as defined in claim 5 , wherein said plate cylinder is an n-segmented cylinder, where n is an integer 2 or more, for supporting printing plates n in number, said forward-end clamping jaw, said forward-end clamping jaw switching means, said rear-end clamping jaws said rear-end clamping jaw switching means and said straining means, respectively, are n in number and arranged equidistantly.

7. A printing plate mounting apparatus as defined in claim 1 , further comprising plate pop-up means for projecting one of the forward end and the rear end of said printing plate outwardly of an outer periphery of said plate cylinder when one of said forward-end clamping jaw and said rear-end clamping jaws is opened to remove said printing plate from said plate cylinder.

8. A printing plate mounting apparatus as defined in claim 7 , further comprising a guide member disposed adjacent said outer periphery of said plate cylinder for guiding, toward a plate store, said one of the forward end and the rear end of said printing plate projected by said pop-up means outwardly of said outer periphery of said plate cylinder.

9. A printing plate mounting apparatus as defined in claim 7 , wherein said pop-up means includes pop-up elements movable between a contained position where distal ends of said pop-up elements are contained inside said plate cylinder, and a pop-up position where said distal ends project outwardly of said plate cylinder.

10. A printing plate mounting apparatus as defined in claim 9 , wherein said pop-up means is connected through a link mechanism to one of said forward-end clamping jaw switching means and said rear-end clamping jaw switching means.

11. A printing plate mounting apparatus for mounting a printing plate peripherally of a plate cylinder, comprising:

a forward-end clamping jaw disposed peripherally of said plate cylinder for pinching a forward end of said printing plate with a clamping base;

a forward-end clamping jaw switching means disposed on one end surface of said plate cylinder for opening and closing said forward-end clamping jaw;

a plurality of rear-end clamping jaws disposed peripherally of said plate cylinder for pinching a rear end of said printing plate with a clamping base;

a rear-end clamping jaw switching means disposed on one end surface of said plate cylinder for opening and closing said plurality of rear-end clamping jaws together;

straining means disposed on said plate cylinder for moving said rear-end clamping jaws in a direction for straining the printing plate pinched;

a plate pop-up means housed inside of said plate cylinder for popping up the printing plate when discharging the printing plate mounted on a periphery of said plate cylinder by opening said rear-end clamping jaws; and

a plate pop-up driving means, which is capable of activating independently of the opening of said rear-end clamping jaws, for projecting rear end of said printing plate from an outer periphery toward the outside of said plate cylinder.

12. A printing plate mounting apparatus as defined in claim 11 , wherein said straining means further strain the printing plate pinched by said forward-end clamping jaw and said rear-end clamping jaws, by rotating one of said forward-end clamping jaw and said rear-end clamping jaws with the clamping base.

13. A printing plate mounting apparatus as defined in claim 12 , wherein said plate cylinder is an n-segmented cylinder, where n is an integer 2 or more, for supporting printing plates n in number, said forward-end clamping jaw, said forward-end clamping jaw switching means, said rear-end clamping jaws, said rear-end clamping jaw switching means and said straining means, respectively, are n in number and arranged equidistantly.

14. A printing plate mounting apparatus as defined in claim 11 , wherein said forward-end clamping jaw switching means and said rear-end clamping jaw switching means include air cylinders, respectively, said air cylinders being connected to an air source disposed outwardly of said plate cylinder, through a rotary joint disposed axially of said plate cylinder.

15. A printing plate mounting apparatus as defined in claim 14 , further comprising mechanical valves each disposed between one of said air cylinders and said rotary joint to be rotatable with said plate cylinder and contacting a contact member disposed outwardly of said plate cylinder to vary air supply to said one of said air cylinders.

16. A printing plate mounting apparatus as defined in claim 15 , wherein said plate cylinder is an n-segmented cylinder, where n is an integer 2 or more, for supporting printing plates n in number, said forward-end clamping jaw, said forward-end clamping jaw switching means, said rear-end clamping jaws, said rear-end clamping jaw switching means and said straining means, respectively, are n in number and arranged equidistantly.

17. A printing plate mounting apparatus as defined in claim 11 , further comprising a guide member disposed adjacent said outer periphery of said plate cylinder for guiding, toward a plate store, said one of the forward end and the rear end of said printing plate projected by said pop-up means outwardly of said outer periphery of said plate cylinder.

18. A printing plate mounting apparatus as defined in claim 11 , wherein said pop-up means includes pop-up elements movable between a contained position where distal ends of said pop-up elements are contained inside said plate cylinder, and a pop-up position where said distal ends project outwardly of said plate cylinder.

19. A printing plate mounting apparatus as defined in claim 18 , wherein said pop-up means is connected through a link mechanism to one of said forward-end clamping jaw switching means and said rear-end clamping jaw switching means.