Printing – Processes – With heating or cooling
Patent
1995-03-23
1996-01-23
Eickholt, Eugene H.
Printing
Processes
With heating or cooling
B41F 2304
Patent
active
054857856
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to a process for maintaining a set contact pressure in the form of a roller mark of a metal roller provided with a synthetic blanket against a printing cylinder of a rotary printing press having a short inking unit, and to a device for executing the process.
DESCRIPTION OF THE PRIOR ART
A device for setting the contact pressure of ink application rollers against the printing cylinder is known from DE 21 55 496 C2, by means of which a reference ring is moved against cams, so that the shafts, of the ink application rollers, which are provided with resilient surfaces, can be adjusted in relation to the printing cylinder. The reference ring has an arm for this purpose, which can be adjusted by means of a set screw.
An inking unit is known from FR-A-73 06 691, wherein a temperature compensating device for a metering gap between a pivotably suspended metering roller and a transfer roller is said to be possible. The temperature compensating device only acts in response to room temperature changes. This prior art device may not be able to absorb the considerable hydrodynamic forces acting on the metering roller. This therefore may result in uneven ink metering.
It is disadvantageous in connection with the first mentioned prior art device that the subsequent adjustment, in respect to time as well as to the amount of the adjustment, of the pressure of the rubber roller takes place at the discretion of the operator after the rotary printing press has been placed in operation, so that a temperature-dependent ink supply to the printing cylinder cannot be ruled out.
SUMMARY OF THE INVENTION
It is the object of the invention to provide a process and a device for executing the process for an inking unit by means of which it is possible to keep the width of the so-called roller mark formed by pressure of the ink application roller against a printing cylinder approximately constant during temperature changes of the ink application roller.
The present invention provides a device and a process for maintaining a set contact pressure per defined width of a roller mark of an ink application roller provided with a synthetic or resilient cover, such as rubber, against a printing cylinder of a rotary printing press when the temperature of the roller or cylinder changes. The ink application roller is pressed against an adjustable detent or stop that is fixed on the press frame. Movement of the ink application roller toward or away from the printing cylinder is accomplished by use of a temperature compensating element as a function of the heating change of the ink application roller.
The following advantages in particular ensue in the course of utilizing the invention. By means of an always evenly formed roller mark, independently of the degree of heating of the rubber blanket, an even print quality is assured by means of even ink application. The subject of the invention is particularly advantageously employable in connection with Anilox offset short inking units and particularly in those cases where the printing cylinder and the ink application roller are of the same diameter. In addition, the tendency for scumming can be reduced. The invention is not limited to offset short inking units. The quantity of ink transferred from the ink application roller to a printing plate, for example an offset printing plate, of a printing cylinder over a temperature range between start-up temperature and operating temperature, and thus the quality of the transfer of the ink from the ink application roller to the printing plate can be kept approximately constant in this manner.
It is furthermore avoided that too strong a contact pressure might be created between the printing cylinder and the ink application roller and that therefore scumming occurs. Too strong a contact pressure can also lead to a kneading effect of the resilient or plastic covering of the ink application roller and thus to the destruction of the resilient covering.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be explai
REFERENCES:
patent: 2501495 (1950-03-01), Carroll et al.
patent: 3131631 (1964-05-01), Haskin
patent: 3691956 (1972-09-01), James et al.
patent: 3888173 (1975-06-01), Ritzerfeld
patent: 4037531 (1977-07-01), Ritzerfeld
patent: 4502386 (1985-03-01), Cappel et al.
patent: 5148742 (1992-09-01), Stirbis et al.
patent: 5188028 (1993-02-01), Reichel
patent: 5295437 (1994-03-01), Philippe
patent: 5370046 (1994-12-01), Spiegel et al.
patent: 5789960 (1993-03-01), Valentini et al.
Rothlein Ewald
Schneider Georg
Eickholt Eugene H.
Koenig & Bauer Aktiengesellschaft
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