Printing – Multicolor – Rotary machines
Reexamination Certificate
1999-09-23
2001-10-30
Hilten, John S. (Department: 2854)
Printing
Multicolor
Rotary machines
C101S171000, C101S180000
Reexamination Certificate
active
06308619
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus for diverting a wet printed web in web-fed rotary printing presses.
RELATED TECHNOLOGY
In web-fed rotary printing presses, a running paper web is fed through one or more printing units to apply a single or a multicolour image on one or on both sides of the web.
Afterwards, the wet printed web is fed to a dryer for drying the wet ink and afterwards fed to a subsequent folder section in which the printed web is folded and cut into signatures. However, in printing presses having a plurality of printing units for printing multicolor images to the web, it may be desired for certain print jobs to only print one color to the web. In such cases, it is known to divert the web around the printing units which are not needed for a specific print job, rather than passing the web through the printing units which usually results in a smearing of the freshly printed image. For diverting the web around the inactive printing units, it is known to pass the web over lead rolls which are located above the printing units to be bypassed.
In printing presses, in which the printing units are arranged one above the other in tower arrangements, and in which the web is running substantially vertically through the printing units of a tower arrangement, lead rolls are used to deflect the web when running from one printing unit to another, in order to obtain a certain wrap of the web around the cylinders of the units, or are used to guide the web from one tower arrangement to another tower arrangement.
The known lead rolls, however, show the deficiency that although their surface is usually coated with chromium, ink is transferred from the web to the chromium surface of the lead rolls, resulting in a build up of ink on the surface which causes a smearing of the printed image.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide for an apparatus for diverting a wet printed web in a web-fed rotary printing press, in particular in a lithographic offset printing press, which avoids smearing of the freshly printed image when diverting the web before passing it through a dryer of the printing press.
The present invention therefore provides an apparatus for diverting a wet printed web in a web-fed rotary printing press comprising a diverting roll over which the wet printed web is passed and further comprises a water solution applicator for directly applying a water solution to the diverting roll. The water solution is preferably dampening liquid or dampening solution which is used in a dampening unit of a lithographic printing press.
The diverting roll advantageously may have a hydrophilic surface, as e. g. chromium.
The water solution applicator may comprise a water solution applicator roll which contacts the diverting roll. The water solution applicator roll advantageously is a rubber coated roll which is in contact with a further pan roll which receives water solution from a water solution reservoir and transfers it to the water solution applicator roll.
According to another embodiment of the invention, the water solution applicator comprises a spray nozzle arrangement which sprays the water solution directly onto the diverting roll.
REFERENCES:
patent: 852429 (1907-05-01), Gauch
patent: 902165 (1908-10-01), Pancoast
patent: 1970929 (1934-08-01), Wood
patent: 2329152 (1943-09-01), Breyer
patent: 3705451 (1972-12-01), Dahlgren
patent: 3924531 (1975-12-01), Klingler
patent: 3937141 (1976-02-01), Dahlgren
patent: 4841903 (1989-06-01), Bird
patent: 5651316 (1997-07-01), DeMoore et al.
patent: 5695180 (1997-12-01), Kunzle
patent: 5782182 (1998-07-01), Ruckmann et al.
patent: 6145435 (2000-11-01), Richards
Heidelberger Drukmaschinen AG
Hilten John S.
Kenyon & Kenyon
Nolan, Jr. Charles H.
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