Variable format offset printing machine having a central impression cylinder

1. A variable format offset printing machine having a central impression cylinder, said printing machine comprising said central impression cylinder ( 1 ) on which a web printable substrate (B) is supported and a plurality of printing stations arranged around the central impression cylinder ( 1 ), each of said printing stations comprising a blanket cylinder ( 2 ) of variable diameter, a plate cylinder ( 3 ) of variable diameter, and an offset inking unit ( 4 ), said blanket cylinder ( 2 ), plate cylinder ( 3 ) and offset inking unit ( 4 ) being movable between respective withdraw positions and respective multiple working positions for different diameters of the blanket and plate cylinders ( 2 , 3 ), characterized in that in at least one of said printing stations:

the axis of the blanket cylinder ( 2 ) and the axis of the plate cylinder ( 3 ) are comprised in a first plane (P 1 ) inclined with respect to a horizontal plane, wherein said first plane (P 1 ) does not comprise the axis of the central impression cylinder ( 1 ) at several of said multiple working positions for different diameters of the blanket and plate cylinders ( 2 , 3 );

the axis of the blanket cylinder ( 2 ) and the axis of the plate cylinder ( 3 ) are movable in respective first and second horizontal planes (Hp 1 , Hp 2 ); and

said first plane (P 1 ) forms an angle (A) ranging from 0° to 20° in absolute value with a second plane (P 2 ) comprising the axis of the central impression cylinder ( 1 ) and the axis of the blanket cylinder ( 2 ) at any of said multiple working positions for different diameters of the blanket and plate cylinders ( 2 , 3 ).

2. The printing machine according to claim 1 , characterized in that the blanket cylinder ( 2 ) and the plate cylinder ( 3 ) are rotatingly supported on respective first and second supports ( 5 , 6 ) connected to a main frame ( 8 ) rotatingly supporting the central impression cylinder ( 1 ) by respective first and second linear guidance means.

3. The printing machine according to claim 2 , characterized in that said first and second linear guidance means are first and second horizontal guidance means.

4. The printing machine according to claim 2 , characterized in that in all the printing stations are located above and below a central horizontal plane (Chp), said first supports ( 5 ) are identical design and symmetrically positioned both with respect to said central horizontal plane (Chp) and to a central vertical plane (Cvp) and said second supports ( 6 ) are identical design and symmetrically positioned both with respect to the central horizontal plane (Chp) and to said central vertical plane (Cvp).

5. The printing machine according to claim 2 , characterized in that the main frame ( 8 ) has opposite operator and gear sides, and each first support ( 5 ) comprises an operator side first support ( 5 a ) and a gear side first support ( 5 b ) independently movable from each other, and each second support ( 6 ) comprises an operator side second support ( 6 a ) and a gear side second support ( 6 b ) independently movable from each other.

6. The printing machine according to claim 2 , characterized in that the main frame ( 8 ) has opposite web inlet and web outlet sides, and the offset inking units ( 4 ) of all the printing stations which are located at one and the same web inlet or web outlet side of the central impression cylinder ( 1 ) are mounted on at least one auxiliary frame ( 7 ) in which the offset inking units ( 4 ) are superposed on one another and staggered so as to follow the circumference of the central impression cylinder ( 1 ), said auxiliary frame ( 7 ) being movable in a linear horizontal direction between withdrawn and working positions.

7. The printing machine according to claim 6 , characterized in that the auxiliary frame ( 7 ) when is in its withdrawn position provides a space between the same auxiliary frame ( 7 ) and all the first and second supports ( 5 , 6 ) located at the same web inlet or web outlet side of the main frame ( 8 ) permitting access for an operator therein.

8. The printing machine according to claim 6 , characterized in that the uppermost and lowermost offset inking units ( 4 ) are attached to upper and lower auxiliary frame-carriers 75 a , 76 a , which are movable connected to upper and lower beams ( 11 , 12 ) extending from a middle region of the main frame ( 8 ).

9. The printing machine according to claim 8 , characterized in that the position of at least said staked uppermost offset inking unit ( 4 ) is shiftable with respect to the rest of the staked offset inking units ( 4 ) forming the auxiliary frame ( 7 ).

10. The printing machine according to claim 8 , characterized in that one or more of the stacked modular offset inking units ( 4 ) is replaced with dummy modular auxiliary units to allow a limited number of printing stations instead of the maximum possible number and/or to allow space for additional drying or curing equipment.

11. The printing machine according to claim 8 , characterized in that any of the stacked modular offset inking units ( 4 ) forming the auxiliary frame ( 7 ) is individually movable between their withdrawn and working positions.

12. The printing machine according to claim 1 , characterized in that at least one of the printing stations comprises an alternative inking unit.

13. The printing machine according to claim 3 , characterized in that the main frame ( 8 ) has opposite web inlet and web outlet sides, and the offset inking units ( 4 ) of all the printing stations which are located at one and the same web inlet or web outlet side of the central impression cylinder ( 1 ) are mounted on at least one auxiliary frame ( 7 ) in which the offset inking units ( 4 ) are superposed on one another and staggered so as to follow the circumference of the central impression cylinder ( 1 ), said auxiliary frame ( 7 ) being movable in a linear horizontal direction between withdrawn and working positions.

14. The printing machine according to claim 4 , characterized in that the main frame ( 8 ) has opposite web inlet and web outlet sides, and the offset inking units ( 4 ) of all the printing stations which are located at one and the same web inlet or web outlet side of the central impression cylinder ( 1 ) are mounted on at least one auxiliary frame ( 7 ) in which the offset inking units ( 4 ) are superposed on one another and staggered so as to follow the circumference of the central impression cylinder ( 1 ), said auxiliary frame ( 7 ) being movable in a linear horizontal direction between withdrawn and working positions.

15. The printing machine according to claim 5 , characterized in that the main frame ( 8 ) has opposite web inlet and web outlet sides, and the offset inking units ( 4 ) of all the printing stations which are located at one and the same web inlet or web outlet side of the central impression cylinder ( 1 ) are mounted on at least one auxiliary frame ( 7 ) in which the offset inking units ( 4 ) are superposed on one another and staggered so as to follow the circumference of the central impression cylinder ( 1 ), said auxiliary frame ( 7 ) being movable in a linear horizontal direction between withdrawn and working positions.

16. The printing machine according to claim 9 , characterized in that one or more of the stacked modular offset inking units ( 4 ) is replaced with dummy modular auxiliary units to allow a limited number of printing stations instead of the maximum possible number and/or to allow space for additional drying or curing equipment.

17. The printing machine according to claim 9 , characterized in that any of the stacked modular offset inking units ( 4 ) forming the auxiliary frame ( 7 ) is individually movable between their withdrawn and working positions.

18. The printing machine according to claim 10 , characterized in that any of the stacked modular offset inking units ( 4 ) forming the auxiliary frame ( 7 ) is individually movable between their withdrawn and working positions.