Printing – Cleaning attachments
Reexamination Certificate
1999-02-04
2003-02-04
Hirshfeld, Andrew H. (Department: 2854)
Printing
Cleaning attachments
C101S423000, C015S256520, C015S256530
Reexamination Certificate
active
06513432
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention relates to a device for cleaning a cylinder in a printing machine, the cylinder having a jacket surface with at least one raised element, particularly at least one gripper for gripping a sheet of printing material, the cleaning device having a cleaner engageable with the jacket surface of the cylinder and being rotatable about an axis of rotation for cleaning the jacket surface.
Impression cylinders and sheet transfer drums installed in printing machines carry grippers which project beyond the periphery of the cylinder. The rotating cylinders are cleaned by cleaners in the form of cleaning rollers, cloths or brushes which can be brought into contact with the cylinders. In order to avoid damage to the cleaner by the grippers, precautions have to be taken.
The published German Utility Model Document DE 295 16 979 U1 describes a washing device for cleaning cylinders of an offset printing unit. The cylinders to be cleaned carry elevated grippers, and the cleaner is formed as a washing roller that rotates during cleaning. A control device is provided, by which the washing roller can be lifted away over rows of the grippers. With this washing device as the cleaner, it is possible to perform a more effective cleaning of the cylinder than with a cleaner in the form of a cloth. The rotation of the washing roller produces an increase in the relative movement between the surface to be cleaned and the cleaner. However, a lifting device is needed in order to lift the washing rollers over and beyond the rows of grippers, and thus a high outlay in terms of construction and control is necessary. The washing roller that is installed is not formed as a brush roller. The cleaning action is therefore lower, than with cleaners provided with brushes. Washing liquid which is sprayed on the washing roller is doctored off the latter by a wiper.
Furthermore, Japanese Patent 3-75348 describes a device for washing impression cylinders of an offset printing machine, in which the cleaner is in the form of a cloth which is pressable against the cylinders by two pressure plates. The pressure plates are formed with recesses which correspond to the grippers. One of the pressure plates is constructed so as to be laterally displaceable. The displacement of the one pressure plate occurs before it strikes the gripper and as a function of or in accordance with a signal transmitted by a detector that detects the grippers. The lateral displacement takes place alternately in two directions in order to compensate for the cloth slipping to one side on the pressure plates. Although the cleaner can be held in a position wherein it is in permanent or continuous contact with the rotating cylinder during the cleaning operation, effective cleaning of the cylinder is not possible with this device, because the relative movement between the cloth, which does not rotate during the cleaning operation, and the cylinder is produced only by the rotation of the cylinder. The cloth is not suitable for various types of soiling and surface structures of cylinders, in particular for removing paper particles stuck to a rough cylinder jacket surface. With this cloth pressed against the cylinder, the cleaning takes a comparatively long time in many cases, because the scouring action is low. Because the cloth does not have any cutout or recess through which the grippers can pass, it unavoidably becomes severely deformed, which reduces the cleaning quality.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a device for cleaning a cylinder with a raised or elevated element in a printing machine, which is compact and of simple construction.
With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, a device for cleaning a cylinder in a printing machine, the cylinder having a jacket surface with at least one raised element, the cleaning device comprising a cleaner engageable with the jacket surface of the cylinder and being rotatable about an axis of rotation for cleaning the jacket surface, the cleaner being formed with at least one recess through which the at least one raised element is able to pass.
In accordance with another feature of the invention, the cleaner is formed as a roller.
In accordance with a further feature of the invention, the roller is a brush roller.
In accordance with an added feature of the invention, the at least one recess extends in a circumferential direction of the cleaner over a circumferential angle less than 360°.
In accordance with an additional feature of the invention, the cleaner is formed as a roller, and the at least one recess is a single flat formed on the roller.
In accordance with yet another feature of the invention, the cleaning device includes a rotary drive for rotating the cleaner to match the rotation of the cylinder so that the at least one raised element passes contact-freely through the at least one recess.
In accordance with yet a further feature of the invention, the cleaning device includes a rotary drive for rotating the cleaner to match the rotation of the cylinder so that the at least one raised element passes without hindrance through the at least one recess.
In accordance with yet an added feature of the invention, the cleaner is nonuniformly rotatable while the at least one raised element passes through the at least one recess.
In accordance with yet an additional feature of the invention, the rotation of the cleaner is delayable while the at least one raised element is passable through the at least one recess.
In accordance with still another feature of the invention, the cleaning device includes a plurality of recesses extending in circumferential direction of the cleaner.
In accordance with still a further feature of the invention, the cleaner is formed as a roller, and each of the recesses is formed by an annular groove on the roller.
In accordance with still an added feature of the invention, the recesses extend in the circumferential direction of the cleaner over a circumferential angle of 360°.
In accordance with still an additional feature of the invention, the cleaning device includes an oscillatory drive for oscillating the cleaner parallel to the jacket surface of the cylinder
In accordance with another feature of the invention, the cleaner is oscillatable axially by the oscillatory drive so that the raised element is passable through the recess without hindrance.
In accordance with a further feature of the invention, the cleaner is nonuniformly oscillatable.
In accordance with an added feature of the invention, the oscillations of the cleaner are delayable while the raised element is passable through the recess.
In accordance with an additional feature of the invention, the cleaning device includes at least one of a gear mechanism and an electronic control for matching the rotation of the cleaner to the rotation of the cylinder.
In accordance with yet another feature of the invention, the cleaning device includes at least one of a gear mechanism and an electronic control for matching the oscillations of the cleaner to the rotation of the cylinder.
In accordance with another aspect of the invention, there is provided a printing machine in combination with at least one cleaning device as defined hereinabove.
During the cleaning process, the cleaner can remain permanently or continuously in a position wherein it is in contact with the cylinder. This is achieved by shaping the cleaner so that it is matched to the elevated element or elements, each elevated element being assigned at least one recess corresponding thereto on the cleaner.
The cylinder may be a cylinder which carries a sheet of printing material in a gripper, which preferably forms the elevated element. A further type of elevation is represented by tools arranged on the cylinder jacket surface, for example stamping or cutting tools for processing the printing material in line in the printing machine. The cylinder may carry a number of elevated elements arranged in a ro
Greenberg Laurence A.
Heidelberger Druckmaschinen AG
Hirshfeld Andrew H.
Locher Ralph E.
Nguyen Anthony H.
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