Apparatus for supplying a varnishing cylinder of a varnishing machine with a varnish film

An apparatus for supplying a varnishing cylinder of a sheet varnishing machine with a varnish film includes a varnish feed roller for depositing the varnish film on the varnishing cylinder, a pressure roller cooperating with the varnish feed roller for supplying the varnish film, a varnish basin formed between the varnish feed roller and the pressure roller, scraper blades engaging the varnish feed roller and the pressure roller, respectively, and submerged in the varnish basin, and a common device for holding the scrapper blades.

BACKGROUND OF THE INVENTION 
The present invention relates to an apparatus for supplying a varnishing 
cylinder of a sheet varnishing machine with a varnish film and including a 
varnish feed roller for depositing the varnish film on the varnishing 
cylinder, a pressure roller cooperating with the varnish feed roller for 
supplying the varnish film, and a varnish basin formed between the varnish 
feed roller and the pressure roller, with at least one scrapper blade for 
scrapping varnish from the pressure roller. 
Here, the term "varnishing machine" is preferably used for designating a 
varnishing machine for one-sided varnishing of plate-shaped metal sheets, 
with the sheets being displaceable between a varnishing cylinder, having 
an outer surface formed of rubber or another elastic material, and hard 
pressure cylinder, and with the varnish feed roller having an inelastic 
outer surface. In a corresponding printing machine or press, usually print 
ink is transferred from an ink feed roller to a plate cylinder. Here, a 
sheet varnishing machine is used, e.g., in manufacturing of drink cans, 
glazing caps, crown caps, where varnishing of inner and outer surfaces 
precedes printing, which is followed with protective varnishing. In these 
cases, the varnish should meet specific requirements so that the varnish, 
upon subsequent pressing or deep-drawing of the sheets, would not crack. 
To form a stripe-shaped outer surface of a sheet for enable welding, 
conventionally elongate recessing doctor blades are used, from which the 
above-mentioned scrapper blades distinguish by their shape and function. 
The scrapper blades serve primarily for supplying a varnishing cylinder 
with a varnish film having a high uniformity, which permits to eliminate 
varnish splitting and phantom layering by the unused varnish field of the 
varnishing cylinder when a new varnish film is formed on the varnishing 
cylinder. Often, intermediate rollers are used which simply smudge the 
varnish splittings. The use of intermediate rollers increases the cost of 
the varnishing machines. 
Austrian patent N246, 185 discloses a supplying apparatus of the 
above-mentioned type but relating to an inker mechanism for a printing 
press, in which an oil ink is used and in which the application roller, 
which is made of an elastic material, transfers ink onto an engraving 
roller. There is provided an ink scrapper for forming a dammed area for 
the ink substance in the vicinity of the contact line of the ink roller 
and the transfer roller. The scrapper is provided on the ink roller. The 
ink and the transfer roller are rotatable in the same direction. At that, 
changing of the circumferential or angular speed of the ink roller 
relative to the transfer roller is possible. The object of patent No. 
246,185 is to provide simple means for operational control of the ink film 
thickness. The ink, which remains on the transfer roller, after the ink 
transfer to the engraving plates of the plate cylinder, is transferred 
back to the dammed area by the transfer roller. There is provided a second 
ink scrapper on the other half of the ink roller to insure a complete 
removal of the ink film. The transfer roller, which returns the ink back 
to the dammed area, is not equipped with any ink scrapper and, therefore, 
the unused amount of ink does not affect the formation of the new film on 
the plate cylinder. 
The object of the present invention is an apparatus for supplying a 
varnishing cylinder of a varnishing machine, which would have a simple 
structure and would take up little space. Another object of the invention 
is a supplying apparatus of the above-described type in which the unused 
varnish field on the varnishing cylinder does not affect formation of a 
new film on the varnishing cylinder. 
A further object of the invention is a supplying apparatus of the 
above-mentioned type which would insure convenient cleaning and would 
provide for a more rapid change of the varnish when necessary. 
SUMMARY OF THE INVENTION 
These and other objects of the invention, which will become apparent 
hereinafter, are achieved by providing two scrapper blades which cooperate 
with both pressure and varnish feed rollers, which are submerged into the 
varnish basin, and which supported by a common holding device. 
The two scrapper blades insure removal of the varnish from both pressure 
and feed rollers which results in the optimal formation of a new varnish 
film on both rollers, and non-uniformity, which might have resulted from 
varnish splitting-off or other varnish condition, is eliminated. Providing 
only two rollers substantially reduces the space required for the 
supplying apparatus. Arranging the two scrapper blades adjacent to each 
other further reduces the space required for the apparatus. Providing a 
common holding device insure simultaneous lifting of both blades and 
facilitate cleaning, as well as removal of the varnish unit, which 
accelerates varnish change. Adjustment of the scrapper blade is insured by 
their arrangement on opposite sides of the holding device. This 
arrangement also insureds an equilibrium of forces acting on both scrapper 
blades. Because both scrapper blades are submerged into the varnish basin, 
all of the varnish splittings and the like are almost immediately return 
back to the basin. 
A particular advantage of the inventive apparatus consists in that a rather 
small varnish catch system is required, and a free surface of the 
apparatus for removal of solvent gases is rather limited.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 shows an apparatus according to the present invention for supplying 
a varnishing cylinder 12 of a sheet varnishing machine with a varnish 
film. FIG. 1 shows two plate-shaped metal sheets 10 and 11 movable one 
after another between the varnishing cylinder 12 and a pressure cylinder 
(not shown). The two sheets 10 and 11, the outer surfaces of which are 
varnished, upon moving past the varnishing cylinder 12, form thereon an 
unusable varnish field 13 which, upon further rotation of the cylinder 12, 
is transferred onto a varnish feed roller 14. This varnish deposition is 
removed with a scrapper blade 15, which engages the varnish feed roller 
14, preferably, within varnish basin 17 formed between the varnish feed 
roller 14 and a pressure roller 16, before the renewal of the varnish film 
provided on the varnishing cylinder 12. A corresponding renewal of the 
varnish film, which is formed on the pressure roller 16, is made possible 
by providing a scrapper blade 18 which engages the pressure roller 16 and 
is immersed in the varnish basic 17. 
In addition, in order to integrate into varnish basin 17 as soon as 
possible all of the varnish splittings and varnish deposits, it is insured 
that no amount of mature varnish is deposited on both scrapper blades 15 
and 18, which are completely emerged in the varnish basin 17 and extend 
their substantially horizontally. The advantage of this arrangement 
consists particularly in that the cleansing possibilities and the 
possibilities of a rapid varnish change, are improved. The scrapper blades 
15 and 18 extend at a favorable angle, and the set-up forces of the two 
scrapper blades 15 and 18 can be better combined. To insure providing in 
the varnish basin 17 a varnish flow with the initial condition, at least 
one varnish flow opening 19 is provided between the two scrapper blades 15 
and 18. 
A common holding device 20 of the two scrapper blades 15 and 18 includes a 
support beam 22 having pivot arms 21 for pivoting both scrapper blades 15 
and 18 upward from the varnish feed roller 14 and the pressure roller 16 
and then back downward. This significantly facilitates cleaning and 
general maintenance of the apparatus for supplying the varnishing cylinder 
12 with a varnish film. The flat bar-shaped scrapper blades 15 and 18 lie 
on each other with their wide sides and are releasably connected to the 
support beam 22 with common screws 23 inserted from above. The scrapper 
blade 15, the tapering portion of which is directed toward the varnish 
feed roller 14 which has a larger diameter than the pressure roller 16, 
occupies an upper position. In order to provide for self-adjustment at the 
division of the set-up force between the scrapper blades 15 and 18, the 
pivot arms 21 are longitudinally displaceable on a shaft 24 the axis of 
which is parallel to the axes of the feed roller 14 and the pressure 
roller 16. To insure a convenient dismounting and to accelerate the 
cleaning process, a plug-in connection is formed between each of the pivot 
arms 21 and the shaft 24. 
On each of the opposite ends of the support beam 22, there is provided a 
roller carrier 26, which is pivoted by a pressure cylinder 25 and carries 
a pressure roller 27, which pivots backward into a release position of the 
support beam 22 to apply pressure to the scrapper blades, and a spacing 
roller 28 for deactivating the scrapper blades. The spacing roller 28 
provides an intermediate position for both scrapper blades 15 and 18, 
which is located in the vicinity of their operational position and in 
which the two scrapper blades 15 and 18, together with their common 
holding device 20, are prevented from forcefully hitting the varnish feed 
roller 14 and the pressure roller 16. The pivot 29 of the roller carrier 
26 is connected with a side plate 30 or a back-up side plate of the sheet 
varnishing machine. The same applies to a support member 31 for the 
pressure cylinder 25. In FIG. 1, the operational position of the pressure 
roller 27 is shown with a solid line, and the release position of the 
pressure roller 27 is shown with a dash line. The pressure roller 27 
contacts the upper surface of the support beam 22, whereas the spacing 
roller 28 is engaged in a spherical recess 32 from beneath upon being 
displaced a gap of the support beam 22. For connecting the roller carrier 
26 with the pressure cylinder 25, which is preferably actuated with a 
pressure air, there is provided a rotatable union 33. 
On each of the small sides of the varnish basin 17, there is provided a 
skid wall 35, which pivots together with the respective one of the 
scrapper blades 15 and 18 and which is pressed against the end surfaces of 
the varnish feed roller 14 and the pressure roller 16 with a compression 
spring 34 supported against the support beam 22. The skid plates 35, which 
serves for limiting the varnish basin 17, further facilitate dismounting 
and cleaning of the scrapper blades 15 and 18. When a spare unit of the 
holding device 20, together with the scrapper blades 18, 18 and skid walls 
35, is readily available, changing to another varnish is significantly 
accelerated, and the down-time of the sheet varnishing machine, which 
results from changing of the varnish, is reduced. The compression spring 
34 is located beneath a thrust member 36 of the support beam 22 and inside 
of a spring cage 38 on a carrying bolt 37 of the support beam 22. 
In order to achieve a high uniformity of a new varnish film, which is 
formed on the varnishing cylinder 12, even when the film thickness is very 
small, the varnish feed roller 14 and the pressure roller 16 are rotated 
in opposite directions and, in the region of the varnish basin 17, with a 
step-down speed. Advantageously, the circumferential speed of the pressure 
roller 16 is lower than the circumferential speed of the varnish feed 
roller by about from three to ten percent, because in this case the 
squeezing of the varnish is accompanied by shearing of the varnish. Due to 
the fact that the varnish feed roller 14, the pressure roller 16, and the 
varnishing cylinder 12, which is driven synchronously with the 
displacement of workpieces, have all different outer diameters, localized 
varnish splitting on the varnish feed roller 14 is prevented, since the 
unusable varnish field 13 of the varnishing cylinder is held stationary on 
the varnishing cylinder 12 to keep clean the bottom sides of the following 
one another sheets 10 and 11. 
The varnish supplying apparatus is primarily designed for use in a sheet 
varnishing machine for varnishing plate-shaped thin metal sheets 10, 11, 
as they are shown in FIG. 1. However, the apparatus can be used for 
one-side varnishing of any plate-shaped and laminated workpieces, such as 
cardboard and paper work pieces. The improved varnishing process is 
particularly important when the free areas for a glue material are 
provided on the foldable blanks during varnishing. 
Though the present invention was shown and described with reference to the 
preferred embodiments, various modifications thereof will be apparent to 
those skilled in the art and, therefore, it is not intended that the 
invention be limited to the disclosed embodiments or details thereof, and 
departure can be made therefrom within the spirit and scope of the 
appended claims.