This application claims the priority of German Patent Document No. 10 2004 047 168.1, filed Sep. 29, 2004, the disclosure of which is expressly incorporated by reference herein.
BACKGROUND AND SUMMARY OF THE INVENTION
The invention relates to a printing unit of a printing press.
Printing units of web-fed rotary presses, in particular of newspaper presses, have a plurality of press units, every press unit comprising a transfer cylinder, a form cylinder and an inking unit and damping unit. Furthermore, printing units of this type can have impression cylinders, it being possible for an impression cylinder to interact with one or more transfer cylinders of different press units. In addition to printing units which have impression cylinders of this type, printing units which do not have any impression cylinders are also known, the transfer cylinders of two press units rolling on one another in printing units of this type without impression cylinders. Rubber blankets are usually clamped on the transfer cylinders and printing plates on the form cylinders, for which reason the transfer cylinders are also called rubber-covered cylinders and the form cylinders are also called plate cylinders. The inking unit of a press unit serves to apply printing ink onto the form cylinder of the press unit, whereas the damping unit serves to apply a damping solution onto the form cylinder of the press unit.
In web-fed rotary presses, a distinction is made in principle between printing units which apply the damping solution onto the form cylinder of the respective press unit via direct damping-solution supply or via indirect damping-solution supply. In press units having indirect damping-solution supply, a damping-solution applicator roll of the damping unit rolls firstly on the form cylinder and secondly on an ink distributor roll of the inking unit of the respective press unit, the damping solution being applied to the form cylinder firstly directly via the damping-solution applicator roll and secondly indirectly via ink applicator rolls of the inking unit. In press units of this type having indirect damping-solution supply, the damping-solution applicator roll is driven by way of friction by the ink distributor roll. In contrast, in press units having direct damping-solution supply, the damping-solution applicator roll rolls only on the form cylinder and not on the ink distributor roll, with the result that the damping solution passes to the form cylinder only directly via the damping-solution applicator roll. In press units having direct damping-solution supply, the damping-solution applicator roll is either assigned a dedicated drive or the damping-solution applicator roll is driven mechanically via a gear mechanism. Printing units or press units of printing units of this type have not been disclosed up to now which also make direct damping-solution supply possible in the event of a machine-side design for indirect damping-solution supply and accordingly in the event of a damping-solution applicator roll without a dedicated drive or without an associated gear mechanism.
Proceeding from this, the present invention is based on the problem of providing a novel printing unit of a printing press.
By way of the printing unit according to the invention, the damping solution can, furthermore, be applied via direct damping-solution supply, in addition to indirect damping-solution supply, in such a way that the damping-solution applicator roll which is set away from the ink distributor roll and is driven by way of friction by the form cylinder rolls only on the form cylinder and thus applies the damping solution to the form cylinder only directly via the damping-solution applicator roll, it being possible, in the event of indirect damping-solution supply, which is selected by the controller or the machine and in the print set-up mode in which the damping-solution applicator roll rolls exclusively on the ink distributor roll and is driven by way of friction by the ink distributor roll, to set the damping-solution applicator roll away from the ink distributor roll of the inking unit more quickly in order to switch over to direct damping-solution supply than it is possible to set the damping unit and thus the damping-solution applicator roll against the form cylinder.
Accordingly, firstly indirect damping-solution supply and secondly direct damping-solution supply in the event of a damping-solution applicator roll which is driven only by way of friction are possible using the printing unit according to the invention, without there being a risk of damaging the damping-solution applicator roll during the switchover from indirect damping-solution supply to direct damping-solution supply. A dedicated drive for the damping-solution applicator roll or a gear mechanism which is assigned to the damping-solution applicator roll can be dispensed with.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred developments of the invention result from the following description. Without being restricted thereto, exemplary embodiments of the invention will be explained in greater detail using the drawings.
FIG. 1 shows a diagrammatic illustration of a printing unit according to the invention in printing operation with indirect damping-solution supply.
FIG. 2 shows a diagrammatic illustration of the printing unit according to the invention in printing operation with direct damping-solution supply.
FIG. 3 shows a diagrammatic illustration of the printing unit according to the invention in the print set-up mode.
FIG. 4 shows a detail of the printing unit according to the invention.
DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a diagrammatic detail of a printing unit 10 according to the invention which has two press units 11 and 12 for printing both sides of a web-shaped printing material 13. FIG. 1 shows only the press unit 11 which is responsible for printing the upper side of the web-shaped printing material 13.
As can be gathered from FIG. 1, the press units 11 and 12 of the printing unit 10 have in each case one form cylinder or plate cylinder 14, printing plates (not shown) being arranged on the form cylinder 14. Printing ink can be applied to the form cylinder 14 via an inking unit 15; in contrast, damping solution can be applied to the form cylinder 14 via a damping unit 16. The printing ink passes from the form cylinder 14 via a transfer cylinder or rubber-covered cylinder 17 finally to the printing material which is to be printed.
FIG. 1 shows that the inking unit 15 has an ink fountain 18, in which printing ink is kept ready. The printing ink passes from the ink fountain 18 via a ductor roll 19 and a film roll 20 which interacts with the ductor roll 19 to inking rolls 21 of the inking unit 15. The inking rolls 21 transfer the printing ink successively to ink applicator rolls 22 which roll on the surface of the form cylinder 14.
The damping unit 16 has a reservoir 23 for damping solution, the damping solution which is kept ready in the reservoir 23 being removed from the reservoir 23 via a removal roll 24 and passing via a chromium-plated roll 25 which rolls on the removal roll 24 to a damping-solution applicator roll 26 which, in the state shown in FIG. 1, rolls firstly on the form cylinder 14 and secondly on an inking roll 21 of the inking unit 15, this inking roll 21 also being referred to as an ink distributor roll 27.
In FIG. 1, the press unit 11 is in printing operation with what is known as indirect damping-solution supply, the damping solution passing in the case of indirect damping-solution supply firstly directly via the damping-solution applicator roll 26 to the form cylinder 14, and secondly being applied indirectly to the form cylinder 14 via the ink applicator rolls 22 as a result of the contact between the damping-solution applicator roll 26 and the ink distributor roll 27.
In a press unit of this type with indirect damping-solution supply, the damping-solution applicator roll 26 is driven in printing operation exclusively by way of friction by the ink distributor roll 27. Accordingly, the damping-solution applicator roll 26 has no dedicated drive. Furthermore, the damping-solution applicator roll 26 is not assigned a gear mechanism. Accordingly, the damping-solution applicator roll 26 is driven exclusively by the ink distributor roll 27 by way of friction with the ink distributor roll 27.
In terms of the present invention, a printing unit 10 is then provided, the press units of which have a damping-solution applicator roll 26 which is driven only by friction for indirect damping-solution supply, it being possible, however, to switch the press units over to direct damping-solution supply. FIG. 2 shows the printing unit 10 according to the invention in the state of direct damping-solution supply in printing operation, in which the damping-solution applicator roll 26 is set away from the ink distributor roll 27 and accordingly rolls exclusively on the form cylinder 14. In direct damping-solution supply in the case of the printing unit according to the invention, the damping-solution applicator roll 26 is driven exclusively by way of friction by the form cylinder 14.
In order then to ensure a switchover between indirect damping-solution supply (see FIG. 1) and direct damping-solution supply (see FIG. 2) without the damping-solution applicator roll 26 being damaged in the switchover in the printing unit 10 according to the invention, the damping-solution applicator roll 26 of which is driven exclusively by friction, it is provided in terms of the present invention, when indirect damping-solution supply is selected by the controller or the machine in the print set-up mode, to set the damping-solution applicator roll 26 away from the ink distributor roll 27 more quickly in order to switch over to direct damping-solution supply than the damping unit 16 or the damping-solution applicator roll 26 is set against the form cylinder 14.
FIG. 3 shows the printing unit 10 in the print set-up mode with indirect damping-solution supply which is selected by the controller, the damping-solution applicator roll 26 rolling exclusively on the ink distributor roll 27 in this state and being driven by the ink distributor roll 27. If then there is to be a switchover from indirect damping-solution supply to direct damping-solution supply by the controller in the print set-up mode (see FIG. 3), the damping-solution applicator roll 26 is set away from the ink distributor roll 27 more quickly according to the invention than the damping unit 16 and thus the damping-solution applicator roll 26 is set against the form cylinder 14. Accordingly, immediately after the damping-solution applicator roll 26 has been set away from the ink distributor roll 27, a state occurs in which the damping-solution applicator roll 26 rotates freely without contact to another roll. After this freely rotating state of the damping-solution applicator roll 26, the entire damping unit 16 and accordingly the damping-solution applicator roll 26 are accordingly set against the form cylinder 14, in order to assume the state of the printing unit shown in FIG. 2 for direct damping-solution supply.
Furthermore, in terms of the present invention, it is provided that every press unit 11 or 12 of a printing unit 10 has in each case one piston/cylinder system, firstly for displacing the damping-solution applicator roll 26 relative to the ink distributor roll 27 and secondly for displacing the damping unit 16 and therefore the damping-solution applicator roll 26 relative to the form cylinder 14. FIG. 4 shows a first piston/cylinder system 28 for displacing the damping unit 16 and therefore the damping-solution applicator roll 26 relative to the form cylinder 14, and a second piston/cylinder system 29 for displacing the damping-solution applicator roll 26 relative to the ink distributor roll 27. As can be gathered from FIG. 4, the two piston/cylinder systems 28 and 29 are coupled to one another in such a way that a throwing-on connection 30 of the piston/cylinder system 28 for the displacement of the damping unit 16 relative to the form cylinder 14 is coupled to a throwing-off connection 31 of the piston/cylinder system 29 for the displacement of the damping-solution applicator roll 26 relative to the ink distributor roll 27, and that, furthermore, a throwing-off connection 32 of the piston/cylinder system 28 for the displacement of the damping unit 16 relative to the form cylinder 14 is coupled to a throwing-on connection 33 for the displacement of the damping-solution applicator roll 26 relative to the ink distributor roll 27. As can be gathered from FIG. 4, a restrictor 34 is connected here between the throwing-off connection 32 of the piston/cylinder system 28, for the displacement of the damping unit 16 relative to the form cylinder 14, and the throwing-on connection 33 of the piston/cylinder system 29 for the displacement of the damping-solution applicator roll 26 relative to the ink distributor roll 27. As can, furthermore, be gathered from FIG. 4, lines 37 and 38 act on the lines 35 and 36, respectively, which serve to couple the throwing-on connections 30 and 33 to the throwing-off connections 32 and 31, respectively, of the two piston/cylinder systems, which lines 37 and 38 serve as inflow lines or outflow lines as a function of the position of a switchable valve 39. In the preferred exemplary embodiment, the system which is shown in FIG. 4 is configured as a pneumatic system from the piston/cylinder systems 28 and 29; the piston/cylinder systems 28 and 29 are operated by compressed air.
FIG. 4 shows the controllable valve 39 in a position in which it is possible, via the pneumatic piston/cylinder systems 28 and 29 which are coupled to one another, to carry out the abovementioned throwing-on movement of the damping unit 16 and thus of the damping-solution applicator roll 26 onto the form cylinder 14, which throwing-on movement is delayed temporally compared with the throwing-off movement of the damping-solution applicator roll 26 from the ink distributor roll 27. In this case, compressed air is introduced via the line 37 into the line 35 and thus firstly into the throwing-on connection 30 of the piston/cylinder system 28 and also into the throwing-off connection 31 of the piston/cylinder system 29. When compressed air is introduced into the throwing-off connection 31 of the piston/cylinder system 29 for the displacement of the damping-solution applicator roll 26 relative to the ink distributor roll 27, compressed air must accordingly escape via the throwing-on connection 33 and then be ventilated via the lines 36 and 38. The same is true for the piston/cylinder system 28 for the displacement of the damping unit 16 relative to the form cylinder 14, it being possible for the compressed air to escape from the throwing-off connection 32 only in a temporally delayed manner and accordingly more slowly than in the piston/cylinder system 29, as a result of the restrictor 34. This ensures that the damping unit 16 and therefore the damping-solution applicator roll 26 are set against the form cylinder 14 in a temporally delayed manner compared with the throwing-off movement of the damping-solution applicator roll 26 from the ink distributor roll 27.
If the valve 39 assumes the second switching position in which the line 38 serves as a feed line and the line 37 serves as an outlet line for ventilation, it follows directly from the switching diagram in FIG. 4 that the damping-solution applicator roll 26 and the damping unit 16 are set away from the form cylinder 14, and the damping-solution applicator roll 26 is set against the ink distributor roll 27, without a temporal delay as a result of the bypass 40 of the restrictor 34, which bypass 40 is active only in one flow direction.
Accordingly, it is possible in the printing unit according to the invention to throw the damping-solution applicator rolls 26 of the respective press units on and off in such a way that they run nearly always at machine speeds, it being possible at the same time to avoid damage to the damping-solution applicator rolls. Furthermore, a dedicated drive or a gear mechanism for the damping-solution applicator rolls can be dispensed with.
LIST OF REFERENCE NUMERALS
10 Printing unit
11 Press unit
12 Press unit
13 Printing material
14 Form cylinder
15 Inking unit
16 Damping unit
17 Transfer cylinder
18 Ink fountain
19 Ductor roll
20 Film roll
21 Inking roll
22 Ink applicator roll
23 Reservoir
24 Removal roll
25 Roll
26 Damping-solution applicator roll
27 Ink distributor roll
28 Piston/cylinder system
29 Piston/cylinder system
30 Throwing-on connection
31 Throwing-off connection
32 Throwing-off connection
33 Throwing-on connection
34 Restrictor
35 Line
36 Line
37 Line
38 Line
39 Valve
40 Bypass
The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.
Patent Application
20100071575
