Back to results
US 6,684,774 B2Granted
Sheet-fed rotary printing press
AssigneeHeidelberger Druckmaschinen AG
InventorsRalf Wadlinger, Rudolf Leib, Günter Stephan
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeHeidelberger Druckmaschinen AG
InventorsRalf Wadlinger, Rudolf Leib, Günter Stephan
Estimating the term…
A sheet-fed rotary printing press has at least one unit which includes an impression cylinder and an additional cylinder assigned to the impression cylinder. The impression cylinder and the additional cylinder are relatively adjustable a spaced distance from one another. A sheet guiding device is disposed on the additional cylinder for keeping sheets of printing material, which have been transported by the impression cylinder past the additional cylinder, away from the additional cylinder, once the spaced distance between the impression cylinder and the additional cylinder has been set.
A sheet-fed rotary printing press, comprising:
A sheet-fed rotary printing press, comprising:
A sheet-fed rotary printing press, comprising:
A sheet-fed rotary printing press, comprising:
A sheet-fed rotary printing press, comprising:
A sheet-fed rotary printing press, comprising:
A sheet-fed rotary printing press, comprising:
A sheet-fed rotary printing press, comprising:
A sheet-fed rotary printing press, comprising:
A sheet-fed rotary printing press, comprising:
A sheet-fed rotary printing press, comprising:
A sheet-fed rotary printing press, comprising:
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
From the US filing history. Foreign family members aren’t listed.
Devices for treating the surfaces of sheets, webs, or other articles in connection with printing: print finishing devices, e.g. for glossing prints
Means preventing smudging of machine parts or printed articles
Devices for pressing sheets or webs against cylinders
Printing machines or presses
Term ended 11 Jul 2018 (estimated)
The invention relates to a sheet-fed rotary printing press having at least one unit which includes an impression cylinder and an additional cylinder assigned to the impression cylinder, the impression cylinder and the additional cylinder being relatively adjustable a spaced distance from one another.
In multicolor sheet-fed rotary printing presses, downline from which a varnishing unit is disposed, the transported sheets are printed with ink only in the initial printing units during the printing operation. Downline printing and varnishing units, respectively, are in an idling mode wherein the rubber blanket cylinder and the varnish blanket cylinder, respectively, are disengaged from the printing cylinder. A small gap is formed therebetween, through which the previously printed sheets are transported. Because of the high press speed, the sheets lift away from the respective printing cylinder, so that the freshly applied ink comes into contact with the rubber blanket or varnish blanket and smears.
The published German Patent Document DE 43 18 777 C2 shows a printing unit of a sheet-fed rotary printing press, wherein devices for aiding or promoting sheet guidance are provided, in order to avoid, respectively, smearing of and damage to the freshly printed image. The provisions taken in the heretofore known devices, however, are not always effective because, for example, in a rear region of the sheet, contact of the sheet end with the rubber blanket or the varnish blanket cylinder occurs, nevertheless, when the printing is performed on stiff sheet material.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
FIG. 1 is a fragmentary diagrammatic side elevational view of a sheet-fed rotary printing press wherein printing and varnishing units have been shut down or stopped;
FIG. 2 is an enlarged fragmentary cross-sectional view of FIG. 1 showing one of the cylinders of the press formed with a cylinder gap having a sheet guiding element disposed therein;
Referring now to the drawings and, first, particularly to FIG. 1 thereof, there is shown therein a sheet-fed rotary printing press having a rubber blanket cylinder 5 and a varnish blanket cylinder 6 separated from a press drive mechanism 17 by a clutch 18 (FIG. 3, for example). The cylinders 5 and 6, respectively, are formed with cylinder gaps 9 oriented opposite to respective impression cylinders 7 and 8, the rubber blanket cylinder 5 and the varnish blanket cylinder 6 being fixed in this position. Sheet guiding elements 10 are provided in the cylinder gaps 9. With this construction according to the invention, in the region of the cylinder gap 9, the spacing or spaced distance to the jacket surface of the respective printing cylinders 7 and 8 is increased, so that a considerably greater clearance or interspace is provided for transporting the sheets. By disposing the sheet guiding elements 10 in the cylinder gaps 9, smear-free transport of the sheets can be improved further yet so that even the ends of the sheets cannot become smeared. With this construction in accordance with the invention, the spacing between the two cylinders of the prior art device is increased many times.
FIG. 1 illustrates part of a multicolor sheet-fed rotary printing press, wherein sheets, which have already been printed by printing units 37, as shown in FIG. 8, are then fed to a printing unit 1 which does not take part in the printing of the sheets. The printed sheets are transported from the printing unit 1 by transfer drums 2 through a varnishing unit 3, which also does not take part in the printing of the sheets, and are then fed to a sheet delivery 4. The rubber blanket cylinder 5 and the varnish blanket cylinder 6 are disengaged from the respective printing cylinders 7 and 8. The rubber blanket cylinder 5 and the varnish blanket cylinder 6 are formed with respective cylinder gaps 9, wherein suitable blanket fasteners are provided in a conventional manner and wherein drive wheels are provided on the axle journals of the cylinders.
In the cylinder gaps 9 of the rubber blanket cylinder 5 and the varnish blanket cylinder 6, there are provided sheet guiding elements 10 which may be embodied as guide baffles or guide tongues 11. The guide baffles/guide tongues 11 can be inserted into the cylinder gaps 9 and fastened or otherwise secured therein. Consequently, when stiff cardboard is printed, for example, the rear or trailing edge of the cardboard sheet can slide along the guide baffles/guide tongues 11 without damaging the imprint.