Impression mechanism for a variable cutoff printing unit

1. A variable cutoff printing unit comprising:

a plate cylinder;

a plate cylinder support removably supporting the plate cylinder;

a blanket cylinder;

a blanket cylinder support removably supporting the blanket cylinder, the blanket cylinder support including a bottom face and a top face that define a blanket cylinder support slot in the blanket cylinder support, the blanket cylinder support movable between an on printing position and an off printing position;

an arm;

a sliding element coupled to the arm and the arm coupled to the blanket cylinder support for moving the blanket cylinder support toward and away from the plate cylinder support, the arm extending into the blanket cylinder support slot such that, in the on printing position, the arm contacts the bottom face of the blanket support slot and does not contact the top face of the blanket cylinder support slot, and in the off printing position, the arm contacts the top face of the blanket support slot and does not contact the bottom face of the blanket cylinder support slot; and

a stopping device for stopping movement of the sliding element to limit the movement of the blanket cylinder toward and away from the plate cylinder to a defined range.

2. The variable cutoff printing unit recited in claim 1 further comprising a blanket actuator for moving the sliding element to move the blanket cylinder support toward and away from the plate cylinder support.

3. The variable cutoff printing unit recited in claim 1 further comprising a frame, the plate cylinder support and the blanket cylinder support being coupled to the frame, the frame including a frame slot defined therein, the sliding element sliding within the frame slot.

4. The variable cutoff printing unit recited in claim 1 wherein the stopping device includes an adjustable block that sets a printing position of the blanket cylinder by stopping movement of the sliding element.

5. The variable cutoff printing unit recited in claim 4 wherein the stopping device includes an actuator for adjusting a position of the adjustable block.

6. The variable cutoff printing unit recited in claim 1 further comprising an impression cylinder, an impression cylinder support supporting the impression cylinder and an impression cylinder support actuator for moving the impression cylinder toward and away from the blanket cylinder.

7. The variable cutoff printing unit recited in claim 6 wherein the impression cylinder support actuator moves the blanket cylinder and the impression cylinder into the on printing position by forcing the impression cylinder support against the blanket cylinder support causing the arm to contact the bottom face of the blanket cylinder support slot.

8. The variable cutoff printing unit recited in claim 1 wherein at least one of the blanket cylinder support and the impression cylinder support includes a cam.

9. The variable cutoff printing unit recited in claim 8 wherein the at least one of the blanket cylinder support and the impression cylinder support including the cam includes a cam actuator for moving the blanket cylinder toward the plate cylinder.

10. The variable cutoff printing unit recited in claim 1 wherein the plate cylinder includes a mandrel supported by the plate cylinder support, the mandrel adapted for supporting a plurality of sleeves of different diameters, each of the plurality of sleeves adapted for supporting a respective printing plate having an effective diameter when on the respective sleeve.

11. The variable cutoff printing unit recited in claim 1 wherein the blanket cylinder includes a mandrel supported by the blanket cylinder support, the mandrel adapted for supporting a plurality of sleeves of different diameters, each of the plurality of sleeves adapted for supporting a respective printing blanket having an effective diameter when on the respective sleeve.

12. The variable cutoff printing unit recited in claim 11 wherein the position of the stopping device is adjustable based on the effective diameter of the printing blanket supported by the blanket cylinder support.

13. The variable cutoff printing unit recited in claim 1 further comprising:

a blanket actuator for moving the sliding element to move the blanket cylinder support toward and away from the plate cylinder support to support plate cylinders and blanket cylinders having different cut-offs;

an impression cylinder;

an impression cylinder support supporting the impression cylinder; and

an impression cylinder support actuator movable between an extended position and a retracted position, the impression cylinder support actuator connected to the impression cylinder support, the impression cylinder support actuator moving the blanket cylinder and the impression cylinder into the on printing position in the extended position by forcing the impression cylinder support against the blanket cylinder support and causing the arm to contact the bottom face of the slot, the impression cylinder support actuator moving the blanket cylinder and the impression cylinder into the off printing position in the retracted position by lowering the impression cylinder support and the blanket cylinder support and causing the arm to contact the top face of the slot.

14. A variable cutoff printing unit comprising:

a frame;

a blanket cylinder;

an additional cylinder;

a blanket cylinder support supporting the blanket cylinder, the blanket cylinder support including a bottom face and a top face that define a slot in the blanket cylinder support, the blanket cylinder movably supported in the frame between an on printing position and an off printing position;

an additional cylinder support supporting the additional cylinder, the additional cylinder support movably supported in the frame for lifting the blanket cylinder support into the on printing position and dropping the blanket cylinder support into the off printing position; and

an arm supported in the frame and extending into the slot such that in the on printing position the arm contacts the bottom face and does not contact the top face, and in the off printing position the arm contacts the top face and does not contact the bottom face.

15. The variable cutoff printing unit recited in claim 14 further comprising an additional cylinder support actuator for moving the blanket cylinder and the additional cylinder into the on printing position by forcing the additional cylinder support against the blanket cylinder support and causing the arm to contact the top face of the slot.

16. The variable cutoff printing unit recited in claim 14 wherein the additional cylinder is an impression cylinder.

17. The variable cutoff printing unit recited in claim 14 further comprising a stopping device for stopping movement of the arm to limit the movement of the blanket cylinder toward the additional cylinder to a range defined by a distance between the bottom face and the top face.

18. The variable cutoff printing unit recited in claim 17 further comprising a stop that is coupled to the arm, the stopping device including an adjustable block for stopping movement of the arm by stopping movement of the stop.

19. The variable cutoff printing unit recited in claim 18 wherein the stopping device includes an actuator for adjusting a position of the adjustable block.

20. The variable cutoff printing unit recited in claim 19 wherein the position of the stopping device is adjustable based on a diameter of the blanket cylinder.

21. The variable cutoff printing unit recited in claim 14 wherein the blanket cylinder includes a mandrel supported by the blanket cylinder support, the mandrel adapted for supporting a plurality of sleeves of different diameters, each of the plurality of sleeves adapted for supporting a respective printing blanket having an effective diameter when on the respective sleeve that defines a diameter of the blanket cylinder.

22. The variable cutoff printing unit recited in claim 21 wherein a spacing between the blanket cylinder support and the additional cylinder support is set based on the effective diameter of the printing blanket supported by the blanket cylinder support.

23. A method of operating a variable cutoff printing unit including a blanket cylinder support having a slot formed therein, an additional cylinder support, an arm extending into the slot, a sliding element coupled to the arm and a stopping device, the method comprising:

setting a position of the blanket cylinder support by contacting the stopping device with the sliding element as the arm contacts a top face of the slot formed in the blanket cylinder support in an off printing position of the blanket cylinder support, wherein the arm is not in contact with a bottom face of the slot; and

moving the blanket cylinder support from the off printing position into an on printing position by contacting the blanket cylinder support with the additional cylinder support so that the arm moves out of contact with the top face of the slot and into contact with the bottom face of the slot.

24. The method recited in claim 23

wherein a first blanket is mounted on the blanket cylinder support, the first blanket having a first effective diameter when mounted on the blanket cylinder support.

25. The method recited in claim 24 further comprising:

removing the first blanket from the blanket cylinder support;

adjusting a position of the stopping device;

placing a second blanket on the blanket cylinder support, the second blanket having a second effective diameter when mounted on the blanket cylinder support, the second effective diameter being different from the first effective diameter;

setting a position of the blanket cylinder support based on the second effective diameter by contacting the stopping device with the sliding element so the arm contacts the top face of the slot formed in the blanket cylinder support; and

moving the second blanket into an on printing position by contacting the bottom face of the slot with the arm.

26. The method recited in claim 25 wherein the second blanket is placed on the blanket cylinder support after the position of the stopping device is adjusted.

27. The method recited in claim 25 wherein the first blanket is supported on the blanket cylinder support by a mandrel supported by the blanket cylinder support and a first sleeve removably mounted on the mandrel, the removing the first blanket from the blanket cylinder support includes sliding the first sleeve off of the mandrel, and the placing the second blanket cylinder on the blanket cylinder support includes placing the second blanket on a second sleeve and sliding the second sleeve onto the mandrel.