This application claims the priority of German Patent Document No. 10 2010 034 350.1, filed Aug. 14, 2010, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a device for regulating the application of dampening solution and if applicable the application of ink in a printing press.
Wetting the non-printing locations on a printing plate with dampening solution and wetting the printing locations with ink is generally known in the case of lithographic printing methods. Metering the dampening solution is controlled via the central control console. In the case of film dampening units, the rotational speed of the dampening distribution roller is triggered and the quantity of dampening solution is controlled manually via the web width through changes in compression between the dipping roller and the dampening distribution roller. In the case of nozzles and centrifugal dampening units, the quantity of dampening solution is controlled via the spraying frequency of the nozzles or via the jaw opening in the case of turbo dampening systems.
The disadvantage of the controlled metering of the quantity of dampening solution is that maladjustments may also occur.
A dampening unit for a printing press is known from German Patent Document DE 10 2004 022 084 A1, which has means for applying a dampening solution to a printing plate and means for adjusting the quantity of dampening solution, wherein a sensor is provided for detecting the quantity of dampening solution applied to a printing plate. In this case, the sensor detects the layer thickness of the dampening solution on the printing plate. The quantity of dampening solution on the printing plate is controlled via a comparison with a predetermined quantity of dampening solution. Thus, this regulation of the quantity of dampening solution is carried out on the basis of sensor measuring data with respect to the layer thickness of the dampening solution.
The object of the invention is improving the regulation of the application of dampening solution and if applicable also the application of ink in a printing press, in particular in a printing couple.
According to a first subject of the invention, a device for regulating the application of dampening solution in a printing press having means for applying a dampening solution on an impression cylinder and means for adjusting the quantity of dampening solution is provided, wherein:
Another subject of the present invention relates to a device for regulating the application of dampening solution in a printing press having means for applying a dampening solution on an impression cylinder and means for adjusting the quantity of dampening solution, wherein:
One difference of the subjects of the invention from the above-mentioned prior art in this case is that it is not necessary for sensor-based detection of the layer thickness of the dampening solution on the printing plate to be carried out. In contrast, the optically detectable printing parameters of the ink applied to the printing substrate, which ultimately bring about the optical impression of the printed ink and thus the result of the printing process, is detected selectively and/or over the entire width of the printing substrate. Detection may take place at any printed location of the printing substrate, for example in areas in which measuring strips are printed or in areas in which subjects, i.e., printed images of any type, are printed in the form of images and/or text. Thus, the ink measuring device is designed in such a way that it detects optically detectable parameters or conditions of the ink applied to the printing substrate, wherein the full-tone density and/or the tonal value increase serve as an indicator or the basis of regulation for required control and regulating processes.
Selective detection means a detection in particular only in the direct optical detection area of the ink measuring device, i.e., insofar as this does not extend over the entire width of the printing substrate, this means an area in the direction of the width of the printing substrate, which has a smaller expansion than the width of the printing substrate. Thus, a results-oriented device is made available. The printing substrate may be configured as a web-like printing substrate, for example as a paper web or paper roll or even as a sheet-like printing substrate, for example as a paper sheet or cardboard sheet.
Furthermore, it was recognized in the course of the invention that instabilities in the time progression of the determined printing parameters of the applied ink such as time fluctuations in the determined printing parameters of the applied ink permit conclusions to be drawn about the quantity of dampening solution and about the necessity for adapting the quantity of dampening solution and therefore can be used as an input quantity for regulating the quantity of dampening solution on the impression cylinder. In particular, in this case periodic fluctuations of printing parameters are used, which are determined by the ink measuring device and which are used by the control and regulating device as the basis for regulating the controlled values. In particular, the amplitude and/or the frequency of these types of periodic fluctuations may be used for the magnitude of regulating the controlled values so that the amplitude and/or the frequency of such periodic fluctuations may be included as an input quantity in a change specification for the controlled values. At the same time, volatile changes in the printing parameters may be used, which are determined by the ink measuring device and which are used by the control and regulating device as the basis for regulating the controlled values. In particular, in this case the intensity (i.e., the amount of change in a printing parameter) of such volatile changes can be used for the magnitude of regulating the controlled values so that the intensity (i.e., the amount of the change in a printing parameter) can be included as an additional or alternative input quantity in a change specification for the controlled values.
The detected printing parameters within the scope of the invention are those parameters that characterize the ink(s) printed on the printing substrate, particularly parameters that characterize the ink density and/or the ink consistency and/or the ink contrast and/or the ink dot size of ink halftone dots and/or the shape of ink halftone dots and/or the relative arrangement of ink halftone dots to each other respectively for the ink(s) applied to the printing substrate.
In this case, it may be provided in particular that the ink measuring device is designed for detecting the full-tone density and/or the tonal value increase of the ink, which is applied to the printing substrate. The ink measuring device may detect optically detectable parameters or conditions of the ink applied to the printing substrate, wherein the full-tone density and/or the tonal value increase serve as an indicator or the basis of regulation for required control and regulating processes.
The ink measuring device may be designed in particular for detecting printing parameters of the applied ink in printed measuring strips and/or for detecting printing parameters of the applied ink in printed subjects. In the case of detecting printing parameters in measuring strips, separate measuring strips are detected from the actual printed image or the printed area of the finished printed copy, which are applied especially for the purpose of detecting printing parameters on the printing substrate. In the case of detecting the printing parameters in printed subjects, printing parameters are detected directly in the actual printed image or printed area of the finished printed copy (also known as “measurement in the image”).
Several ink measuring devices may be provided, which are arranged in a distributed manner over the width of the printing substrate. Thus, an entire measuring area can be detected simultaneously, which includes the entire width of the printing substrate.
The ink measuring device or the several ink measuring devices may be designed as an optical ink measuring device in the form of a camera or a spectrometric device.
In addition, the control and regulating device may be designed for comparing the actual values of the printing parameters of the applied ink determined selectively and/or over the entire width of the printing substrate with predetermined and/or pre-stored target values for the printing parameters of the applied ink determined selectively and/or over the entire width of the printing substrate, wherein means are provided for adjusting the ink quantity on the impression cylinder, wherein in addition the means for adjusting the ink quantity on the impression cylinder are controllable as a function of deviations of the actual values of the printing parameters of the applied ink determined selectively and/or over the entire width of the printing substrate from the predetermined and/or pre-stored target values for the printing parameters of the applied ink determined selectively and/or over the entire width of the printing substrate. As a result, in addition to regulating the application of dampening solution, it is also possible to regulate the application of ink.
A device according to the invention may have for example a film dampening unit having at least one dipping roller and one dampening distribution roller, wherein to adjust the quantity of dampening solution:
However, a device according to the invention may also have for example a centrifugal dampening unit having at least one dampening distribution roller and one dampening form roller, wherein to adjust the quantity of dampening solution:
However, a device according to the invention may also have a spray dampening unit having at least one dampening distribution roller and one dampening form roller, wherein to adjust the quantity of dampening solution:
The control and regulating device may be designed as a self-learning control and regulating device, wherein the settings of the controlled values can be saved in the control and regulating device (3) and can be retrieved as preset data. For this purpose, self-learning algorithms are stored in the control and regulating device, which stores controlled values over several print jobs in a data memory of the control and regulating device, in particular as a function of and linked to data related to the ink used in the print job and/or ink composition and/or type of printing substrate and/or duration of the print job and/or temperature or temperature progression of individual devices of the printing press or the printing couple. In the case of a subsequent print job, these controlled values may be retrieved from the data memory and made available to the control and regulating device as preset data. When starting a new print job, the optimal settings may thus be stored and retrieved for the control and regulating device of the dampening unit as preset data for the next job of this type.
In addition, the control and regulating device is advantageously designed in this respect as self-learning and automatically balances out changes in the roller coatings as a result of swelling or shrinkage.
The ink measuring devices may be designed for detecting printing parameters only on one side of the printing substrate, i.e., be arranged in particular only on one side of the printing substrate, but they may also be designed for detecting printing parameters on both sides of the printing substrate, i.e., be arranged in particular on both sides of the printing substrate. The control and regulating device is then designed accordingly for analyzing the printing parameters on one side and/or on both sides of the printing substrate.
In addition, it is possible to dispense with the arduous determination of a so-called “dampening acceleration curve” for different materials, because the rotational speed of the dampening unit just like the print widths of the dipping roller may be regulated via a control signal of the device according to the invention.
In addition, a device according to the invention is able to identify smudging, scumming and ink degradation in good time and thereby reduce waste in an advantageous manner.
Additional features and advantages of the invention are disclosed in the drawings in conjunction with the following description. The invention will be explained in greater detail in the following on the basis of the associated schematic drawings.
At least one ink measuring device 2 is provided for detecting printing parameters of the ink applied to the printing substrate P, wherein the detection of the printing parameters is carried out selectively or over the entire width B of the printing substrate P in a measuring area MB. Selective detection means a detection in particular only in the direct optical detection area of the ink measuring device, i.e., insofar as this does not extend over the entire width of the printing substrate, this means an area in the direction of the width of the printing substrate, which has a smaller expansion than the width of the printing substrate. A control and regulating device 3 is provided for analyzing the printing parameters of the applied ink determined selectively and/or over the entire width B of the printing substrate P. The means for adjusting the quantity of dampening solution on the impression cylinder 1 are controllable as a function of a time progression of the determined printing parameters of the applied ink.
Instead of a single ink measuring device 2, several ink measuring devices 2 may also be provided, which are arranged in a distributed manner over the width B of the printing substrate P. This allows for the possibility of simultaneously detecting a measuring area MB, which extends over the entire width B of the printing substrate P (for example of a paper web or a paper sheet), as well as for the possibility of simultaneously analyzing the different areas of the printing substrate B and, thus, it is possible to also regulate different areas of the means for applying a dampening solution in different ways, i.e., to regulate the application of dampening solution over the width B of the printing substrate in different ways.
Means for adjusting the quantity of dampening solution on the impression cylinder 1 will now be explained by way of example based on the figures:
The quantity of dampening solution, which is applied to the impression cylinder, depends in particular on the compression between a dipping roller 9 and a dampening distribution roller 8 as well as on the angular adjustment of the dipping roller 9 with respect to the dampening distribution roller 8 and on the dampening distribution roller speed, i.e., on the rotational speed of the dampening distribution roller 8 and/or the rotational speed of the dipping roller 9. Preset values 4 may be predetermined as target values for these settings of compression, angular adjustment and rotation speed, i.e., default values 4a, 4b as target values for the compression between the dipping roller 9 and dampening distribution roller 8, default value 4c as the target value for the angular adjustment of the dipping roller 9 with respect to the dampening distribution roller 8 and default value 4d as the target value for the dampening distribution roller rotational speed or dipping roller rotational speed. This is shown schematically in
The control and regulating device 3 analyzes the printing parameters for the ink(s) applied to the printing substrate P from the signal of the ink measuring device 2. In the process, the actual values of the printing parameters for the ink(s) applied to the printing substrate P will be compared in particular with the target values for the printing parameters for the ink(s) applied to the printing substrate P, and, in addition, in particular an analysis of the time progression of the printing parameters for the ink(s) applied to the printing substrate P will be carried out. In doing so, the control and regulating device 3 determines in particular whether instabilities in the time progression of the determined printing parameters of the applied ink occur, in particular time fluctuations of the printing parameters of the applied ink. From the printing parameters of the applied ink, in particular from the instabilities or fluctuations in the time progression of the determined printing parameters, the control and regulating device 3 determines via an algorithm a change specification for the change of the target value of the compression between the dipping roller 9 and the dampening distribution roller 8 and/or for the change in the target value of the angular adjustment of the dipping roller 9 and/or for the change in the target value of the dampening distribution roller rotational speed or the dipping roller rotational speed with the objective of adjusting the actual values in accordance with the change specification. The changes in the printing parameters for the ink(s) applied to the printing substrate P are observed and detected via the ink measuring device 2 and, after making a comparison between target and actual values, the ascertained deviations are readjusted by corresponding regulating devices 5.
To adjust the compression between dipping roller 9 and the dampening distribution roller 8, two motors 6a, b are provided, which can adjust the roller mountings preferably via spindles. Another motor 6c is provided for the angular adjustment of the dipping roller 9 and a motor 6d is triggered for regulating the rotational speed of the dipping roller. Reaching the target values of the printing parameters is achieved when a so-called “good sheet” is produced. The good sheet has the desired printing quality and the adjusted values for the controlled values 4a, 4b, 4c and 4d may be saved and subsequently retrieved to the control and regulating device 3 for the production of a similar job. Every controlled value 4a, 4b, 4c, 4d by itself or in conjunction with one or several others may be regulated.
The principle according to the invention is shown in
As
In this case,
In addition, an inking couple 25 (shown only schematically) is provided in
Thus, the drive motor M in
A control and regulating device 3 is provided in turn for this, which functions in accordance with the control and regulating device 3 already described above, and for this purpose is connected with a data link to the ink measuring device 2. The preset data V for the to-be-regulated settings of the controlled values may be read into the control and regulating device 3; these data may either be saved in a memory device or be input via a human/machine interface.
Similarly, the inking couple 25 is described in terms of regulation with the control and regulating device 3 in an analogous manner as already described above on the basis of the other examples.
1 Impression cylinder
2 Ink measuring device
3 Control and regulating device
4 Default value (quantity of dampening solution)
5 Regulator
6 Adjusting motors/adjusting devices
7 Form roller
8 Distribution roller
9 Fountain roller/dipping roller
10 Cycle frequency
12 Cycle duration
12 Dampening distribution roller speed
13 Dampening form roller speed
14 Spray bar with nozzles
15 Rotor
16 Shutter
20 Ink duct roller
21 Drive for ink duct roller
22 Ink zone meter
23 Positioning motor for ink zone meter
24 Ink fountain
25 Inking couple
B Width of the printing substrate
FZ Ink zone
GZ Rubber cylinder
IF Actual values of the printing parameters
M Drive motor
MB Measuring area on the printing substrate
MF Measuring field
MS Measuring strip
P Printing substrate
PZ Plate cylinder
S Subject
SF Target values of the printing parameters
V Preset data
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.
Number | Date | Country | Kind |
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10 2010 034 350.1 | Aug 2010 | DE | national |