Moistening device for a roll or a cylinder of an offset press

1 . A moistening device for a roll or a cylinder of an offset press, comprising a chamber-type doctor which is attached for moistening to the roll or to the cylinder, wherein at least one actuator is arranged in an interior of, or outside, the chamber-type doctor, with which actuator a pressing force of the chamber-type doctor on the roll or the cylinder is varied along a length of the roll or the cylinder.

2 . The moistening device according to claim 1 , wherein the roll is an applicator roll or a ductor roll.

3 . The moistening device according to claim 1 , wherein the cylinder is a plate cylinder.

4 . The moistening device according to claim 1 , wherein the chamber-type doctor is divided along the length of the roll or the cylinder into zones and wherein at least one actuator is arranged per zone.

5 . The moistening device according to claim 4 , wherein the chamber-type doctor has elastic connecting points between the zones.

6 . The moistening device according to claim 5 , wherein the elastic connecting points are formed by material cut-outs of the chamber-type doctor and/or by an incorporation of elastic materials in the chamber-type doctor.

7 . The moistening device according to claim 1 , wherein the chamber-type doctor is mounted movably in a housing or frame, the at least one actuator exerting a force between the chamber-type doctor and the housing or frame.

8 . The moistening device according to claim 1 , wherein the at least one actuator has an electric and/or pneumatic and/or hydraulic drive.

9 . The moistening device according to claim 1 , wherein the at least one actuator is formed by at least one compression and/or tension cylinder.

10 . The moistening device according to claim 1 , wherein the at least one actuator is formed by at least one air bellows or fluid bladder.

11 . The moistening device according to claim 1 , wherein the at least one actuator is formed by at least one electromagnet.

12 . The moistening device according to claim 1 , wherein the chamber-type doctor has at least one sealing element in a contact region of the roll or of the cylinder.

13 . The moistening device according to claim 7 , wherein at least one scraper doctor is attached to the housing or the frame.

14 . The moistening device according to claim 1 , wherein the chamber-type doctor forms a hollow space in a contact region of the roll or of the cylinder, into which hollow space a damping solution is introducible under pressure via one or more openings.

15 . The moistening device according to claim 1 , wherein a sensor is arranged on the actuator and/or the chamber-type doctor, which sensor determines the pressing force and supplies a signal for regulation or control of the actuator.

16 . The moistening device according to claim 1 , wherein the roll or the cylinder is of an oscillating configuration.

17 . The moistening device according to claim 1 , wherein a damping-solution sensor is arranged on a damping-solution outlet of the chamber-type doctor, on a damping-solution applicator unit and/or on a plate cylinder, which sensor determines a metered amount of damping solution and supplies a signal for regulation or control of the actuator.

18 . The moistening device according to claim 4 , wherein each of the zones has a dedicated damping-solution supply.

19 . A moistening device for an offset press, comprising:

a housing;

a chamber-type doctor disposed within the housing, wherein a lower portion of the chamber-type doctor is disposed adjacent to a ductor roll; and

an actuator disposed within the housing and in operable engagement with the chamber-type doctor, wherein the actuator applies a pressure force to the chamber-type doctor such that a contact pressure is applied by the lower portion of the chamber-type doctor to the ductor roll along a length of the ductor roll.

20 . The moistening device according to claim 19 , wherein the pressure force is variable along the length of the ductor roll.