Printing – Rolling contact machines – Rotary
Reexamination Certificate
2001-05-21
2004-02-03
Colilla, Daniel J. (Department: 2854)
Printing
Rolling contact machines
Rotary
C101S217000, C101S218000, C101S409000, C101S410000
Reexamination Certificate
active
06684774
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
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.
SUMMARY OF THE INVENTION
In view of the aforementioned prior art, it is an object of the invention of the instant application to provide a sheet-fed rotary printing press which enables smear-free sheet travel when the printing, varnishing or finishing units are shut down.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a sheet-fed rotary printing press having at least one unit including 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, a sheet guiding device 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.
In accordance with another feature of the invention, the additional cylinder is stoppable, so that it will not rotate while the impression cylinder rotates.
In accordance with a further feature of the invention, the sheet-fed rotary printing press includes a clutch via which the additional cylinder is decouplable from a printing-press drive for driving the additional cylinder.
In accordance with an added feature of the invention, the additional cylinder is formed with a cylinder gap approximately alignable with the impression cylinder in a stopped condition of the additional cylinder, for setting the spaced distance between the additional cylinder and the impression cylinder.
In accordance with an additional feature of the invention, the sheet-fed rotary printing press includes a detent for fixing the additional cylinder relative to a printing-press frame, in a position of the additional cylinder wherein the cylinder gap formed therein is in alignment with the impression cylinder, and in a condition wherein the additional cylinder is decoupled from a printing-press drive for driving the additional cylinder.
In accordance with an alternative feature of the invention, the sheet-fed rotary printing press includes a blast air connection for fixing the additional cylinder relative to a printing-press frame, in a position of the additional cylinder wherein the cylinder gap formed therein is in alignment with the impression cylinder, and in a condition wherein the additional cylinder is decoupled from a printing-press drive for driving the additional cylinder.
In accordance with yet another feature of the invention, the sheet guiding device includes at least one sheet guiding element secured to the additional cylinder.
In accordance with another feature of the invention, the additional cylinder has a displaceable outer portion; and the sheet guiding element is disposed at the displaceable outer portion. In particular, the sheet guiding element may be embodied as a surface of the displaceable outer portion.
In accordance with yet another feature of the invention, the additional cylinder is stoppable in a position wherein the displaceable outer portion thereof is disposed opposite the impression cylinder.
In accordance with yet another feature of the invention, the displaceable outer portion of the additional cylinder has a clamping device for a cylinder covering to be mounted on the additional cylinder.
In accordance with another feature of the invention, the displaceable outer portion of the additional cylinder forms part of a circular outer surface of the additional cylinder.
In accordance with yet a further feature of the invention, the displaceable outer portion of the additional cylinder is removably fastened to the additional cylinder.
In accordance with yet another feature of the invention, the displaceable outer portion of the additional cylinder is displaceable into an interior of the additional cylinder.
In accordance with another feature of the invention, the displaceable outer portion of the additional cylinder is mounted so as to be pivotable about an axis aligned parallel to an axis of rotation of the additional cylinder.
In accordance with yet another feature of the invention, the sheet guiding element is an outwardly pivotable sheet guiding element.
In accordance with a further feature of the invention, the sheet guiding element is formed with a surface which, when in an outwardly displaced position, extends concentrically with a surface of the impression cylinder.
In accordance with yet another feature of the invention, the displaceable outer portion of the additional cylinder is displaceable linearly in a direction towards the interior of the additional cylinder.
In accordance with yet a further feature of the invention, the sheet guiding element is formed as at least one guide tongue.
In accordance with an alternative feature of the invention, the sheet guiding element is formed as at least one small wheel.
In accordance with another alternative feature of the invention, the sheet guiding element is formed as at least one blast tube.
In accordance with yet a further feature of the invention, the blast tube is couplable to a blast air connection at an end face of the additional cylinder.
In accordance with yet an added feature of the invention, the additional cylinder is formed with a cylinder gap, and the sheet guiding element being received in the cylinder gap.
In accordance with yet an additional feature of the invention, at least one cylinder of the impression cylinder and the additional cylinder is constructed so as to be engageable with and disengageable from the other for setting the spaced distance between the impression cylinder and the additional cylinder.
In accordance with still another feature of the invention, the sheet-fed rotary printing press includes a cylinder covering or liner on the additional cylinder, the cylinder covering being removable from the additional cylinder for setting the spaced distance between the impression cylinder and the additional cylinder.
In accordance with still a further feature of the invention, the impression cylinder and the additional cylinder, between which the spaced distance is set, are rotatable in common with one another, while the sheet guiding device acts upon the sheet to be printed.
In accordance with still an added feature of the invention, the sheet guiding device includes blast air nozzles disposed on the circumferential surface of the additional cylinder.
In acco
Leib Rudolf
Stephan Günter
Wadlinger Ralf
Colilla Daniel J.
Greenberg Laurence A.
Heidelberger Druckmaschinen AG
Locher Ralph E.
Stemer Werner H.
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