Printing – Processes – With heating or cooling
Reexamination Certificate
2001-01-05
2003-11-11
Nolan, Jr., Charles H. (Department: 2854)
Printing
Processes
With heating or cooling
C101S484000
Reexamination Certificate
active
06644195
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a method and device for adjusting an air guide system in a sheet-fed printing machine. Such air guide systems are used to convey and guide printing material, generally a sheet of paper or cardboard. Such a system includes a large number of different air-assisted elements, such as blowing or blast systems, carrying-air cushions and so forth, referred to as “actuators” in connection with this invention.
The air guide system ensures precise conveyance and guidance of the individual sheets, which are held at the leading edge thereof by grippers. In this regard, the greatest accuracy is involved, specifically, both with respect to the path guidance, i.e., the avoidance of deviations from a desired path predefined by the grippers, and also with respect to chronological sequence. Problems increase as the machine speed increases.
The universal availability of a machine for assignment both to the thinnest papers (bible printing paper) and the thickest cardboards requires, on the one hand, a large adjustment range and, on the other hand, a precise adjustment of the air parameters. In particular, this applies to the pressure at the nozzle outlet and, therewith, also the air velocity and the air volume. These air parameters are controlled by throttle valves or bypass flaps, remotely adjustable motorized valves, speed-controlled air generators, and many others. In this regard, the aforementioned parameters which are critical to sheet conveyance, hereinafter referred to as “conveying parameters”, are adjusted to the specific data of the respective print job.
Parameters which are sheet-specific are, in particular, the grammage, i.e., the weight of the sheet in g/m
2
, and the sheet format. However, other variables are also considered, for example, the stiffness of the sheet or the surface condition thereof. It is believed to be obvious that the conveying parameters have to be selected with a view to the sheet parameters in order to achieve an optimum result, i.e., trouble-free conveyance of the sheet through the entire machine. It may also happen that the parameters of a blowing or blast air nozzle, when the sheet parameters are changed, for example, from a lower to a higher grammage, must be changed at a specific location on the conveying path rather than at another location.
PRINTING MACHINE-SPECIFIC PARAMETERS
Parameters which are specific to printing machines are critical for the operation of the blowing or blast air nozzles. The most important printing machine-specific parameter is the production printing speed, i.e., the machine speed. Further printing machine-specific parameters are the switching on and switching off, i.e., starting and stopping, respectively, of individual printing units, the presence of particular in-line applications: varnishing, drying, measuring, cutting, and so forth.
COMBINED PARAMETERS
Printing form or plate inking and moisture takeup change the printing material properties as they pass through the machine.
With regard to heretoforeknown printing machines, the air parameters of the individual air handlers, i.e., for example, blast air nozzles, respectively, are adjustable only individually. Nevertheless, it has become known heretofore to adjust groups of air handlers. In any event, whenever a new print job is performed, a great number of adjustments have to be made, with sheet-specific parameters differing from the preceding print job and/or with different printing machine-specific parameters, for example, at a higher or lower production printing speed.
From the plethora of all of the possible adjustments, the operator has to find the correct adjustment. The operator therefore has to feel his way empirically to the correct values of the conveying parameters in order to achieve a trouble-free or satisfactory conveying result. In this regard, he or she orients himself or herself, respectively, to the aforementioned physical sheet-specific and machine-specific parameters, as well as combined parameters. This requires not only a great deal of skill on the part of the operator, but is also time-consuming. The operator has to decide, from his or her understanding of the technical/physical effect or from his or her own experience, whether upward or downward corrections are necessary in order to optimize the conveying parameters, in particular the air pressure of the blast nozzles.
Previous attempts at a solution to these problems include the following:
The performance range of the machine was restricted to specific applications, in order to achieve a reduction in the adjustment operations of conveying parameters; the performance of the air generators was limited in order to avoid maladjustments; the operating points and viewing windows directly adjacent the sheet guide path were configured ergonometrically; production was performed at a reduced machine speed because, in the daily business of a print shop or printing plant, for the most part the increased changeover time was not amortized by the higher production printing speed achieved as a result.
All these attempts at finding an appropriate solution were unsatisfactory, specifically in relation to the expenditure of time, to the quality of the printed result and also to the requirements regarding the capability and experience of the operator.
The published European Patent Document EP 0 553 321 B2 describes a device for regulating and/or controlling individual actuating elements such as blast nozzles in the region of a delivery of a sheet-fed printing machine. In this regard, sheet-specific and printing machine-specific characteristic data are fed to a computer. In the case of individual actuating elements, a control device performs a format-dependent adjustment. The computer uses the characteristic data to determine the energy of the sheet oncoming in the delivery and, in addition, ensures that the control variables of the actuating elements apply precisely that amount of energy which corresponds to the energy of the oncoming sheet in the delivery region.
The published German Patent Document DE 197 14 204 A1 describes a device for regulating the blast air on a sheet feeder. In this regard, valves which control the supply of blast air are adjusted in accordance with control characteristic curves which, in turn, for its part, take the sheet properties into account.
The published German Patent Document DE 34 13 179 A1 describes a control and regulating device for a sheet delivery of a sheet-fed printing machine. In this regard, all of the required adjustments of adjustable elements of a sheet delivery are adjusted from a single location and are adapted or matched automatically to the changing conditions in accordance with a predefined or prescribed program.
None of these proposals was able to solve the problems arising here. In particular, it is impossible to take into account parameters which are not contained in the database, which leads fundamentally to maladjustments. There is a basic contrast between
Full automation
Manual adjustment
+ quick
+ flexible
+ no changeover times
+ universal
− no possibility of intervention
+ maximum performance
− never covers 100% of all the
− changeover time very
parameters
high
− many maladjustments
− occur in the machine
− not performable by the printer
− not detectable
− experience base of the printer
− possible error
remains unused
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a method and device for adjusting an air guide system in a sheet-fed printing machine wherein the individual conveying parameters of actuators, such as blast air nozzles, can be adjusted quickly and automatically, even by less experienced personnel, for specific job data having special sheet-specific and printing machine-specific parameters (preset and adaptation), and the ability to exert a manual influence is maintained so that the advantages of full automation are usable together with those of manu
Greenberg Laurence A.
Heidelberger Druckmaschinen AG
Mayback Gregory L.
Nolan, Jr. Charles H.
Stemer Werner H.
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