US3005364A - Process of preparing mated embossing rolls - Google Patents

Description

Oct. 24, 1961 F. BRODERICK PROCESS OF PREPARING MATED EMBOSSING ROLLS Filed July 10, 1959 United States Patent 3,005,364 PROCESS OF PREPARING MATE!) EMBOSSING ROLLS Frank Broderick, P.O. Box 31, New Providence, NJ. Filed July 10, 1959, Ser. No. 826,215 1 Claim. (Cl. 76-107) This invention relates to an embossing process and to embossing rolls for registering embossing patterns accurately with multi-colored designs as used in high speed presses.

One of the disadvantages of mating an embossing design upon a photogravure printing of a label is the difficulty of effecting exact register of design. This is particularly difiicult to accomplish since the color rolls and embossing rolls are run at high speeds.

Moreover, the conventional embossing rolls have undercut edges so that the thin foil, foil coated paper or paper used as label paper, for example, for beer labels is cut and mutilated thereby making the labels worthless.

Prior to this invention register of printing cylinders was obtained in the conventional manner of full color drawing or photograph, black and White artwork and/ or color separated photography, photo composing and cylinder etching. The entire printing registration, being obtained by photography and photo engraving, is extremely accurate. A single small label having six or seven colors may be printed accurately in register by this method with as many as three or four hundred labels produced by a single revolution of the printing rolls. Obviously if a roll to emboss four hundred labels in a single revolution is to be used to emboss sections of this label to register, it is necessary to engrave the four hundred labels on the embossing cylinders with the printing cylinders. This was never done successfully prior to this invention because where the embossing pattern was engraved on the steel embossing cylinder by photo engraving process the undercutting of the acid etching produced sharp cutting edges which cut thru papers and foils and resulted in web breakage and scrap production. Hand tooling such a roll by experienced die cutters raised the cost so high as to make embossing cost prohibitive. Attempts were made to take a key register color photo composed negative glass plate as an index guide and establish index figures in such a manner that the surface of the steel embossing cylinder could be mechanically indexed into a rectangle or square of every label appearing on the photo composed negative. An experienced die cutter would then lay a piece of Celluloid or similar material over a single label design on the glass negative and scribe into the Celluloid the register outline of the pattern to be embossed. He would then fill the scribe lines of the Celluloid with graphite or carbon and transfer the outline to a previously manufactured and varnish coated small cylindrical hob. He would then hand cut the hob with the embossing pattern and place register marks on the hob to coincide with the indexed scribe marks on the steel production embossing roll. The pattern on the small hob would then be hobbed and etched into each small rectangle or square 3,905,364 Patented Oct. 24, 1961 off-register embossing would result. The entire process was extremely costly and scrap losses together with exorbitant costs made it impractical. In cases where attempts to relieve cutting of the paper or foil web by a photo engraved roll resulted in the use of resilient back up rolls such as rubber, the embossing was poorly defined and quickly lost in rewind and spooling operations. Where paper filled or composition back up rolls were used, fold covers of Web or splices going thru the embossing rolls damaged the rolls with resultant down time and cost to repair or replace. Both methods were abandoned.

It is an objective of this invention to provide a process for effecting exact register of an embossing design with a color design in high speed presses.

It is another object to provide a process of embossing at high speed with rotary rolls without mutilating the label paper being embossed.

It is another object to provide a process for effecting registration of an embossing pattern on a pair of steel matched rolls with a multi-colored pattern previously printed on the same press.

These and other objects of this invention will become apparent upon reading the following descriptive disclosure taken in conjunction with the accompanying drawing, in Which- FIG. 1 is a side schematic elevation view of a high speed rotary color press having three pairs of color rolls and an end set of matched embossing rolls made from four films of a master art work of a label by conventional camera staging technique,

FIG. 2 is a top plan view of film of the embossing design used for the end set of rolls,

FIG. 3 is a view of the master or individual art work used for making the composite film of FIG. 2,

FIG.'4' is a view of a roll having a composite film of an embossing design wrapped therearound upon a conventional photo-resist composition applied to the roll surface.

FIG. 5 shows a female hand engraved steel mill roll made from a strip of the film of FIG. 2 of the embossing design of the master art work,

FIG. 6 is a section view of a portion of the mill roll of FIG. 5 showing the rounded edges of the hand engraved design thereon,

FIG. 7 is a section view of a corresponding male mill roll made from the female roll of FIG. 5,

indexed on the production roll. This method is imprac- FIG. 8 is a 'front view of a female production roll made from the male mill roll,

FIG. 9 is a front view of a male production roll made from the female production roll and therefore matched thereto, and

FIG. 10 is a section view of an embossed channel of a female production roll showing the rounded edges obtained by the process of this invention.

According to this invention, the embossed area of a label is treated exactly the same as another color- And when color separations are made for each color another separation is made for embossing. In the case Where four hundred labels would be etched on a single steel cylinder, the cylinder would be etched directly from a photo-composed embossing separated four hundred label film in exact register to its multi-color mated printing cylinders.v At this point the steel embossing cylinder is useless for embossing due to lack of depth and sharp cutting edges. It is temporarily put aside. A single ele- V lishments.

ment label, or two or more depending on intricacy of design,"is then cut out of the four hundred label film and etched into a small cylindrical steel mill or hob. A die cutter then hand tools and polishes this small female hob including radius backgrounds and similar embel- This female hob is hardened and then mated into a male steel mill or hob. We now have a male tool exactly in outline register to the previously photoengraved steel production roll but it has been deepened, radiused and polished so that byhardening and then hobbing this tool into the patterns previously etched into the steel cylinder one obtains accurate registration, deep embossing, rounded contours, no sharp cutting edges and a polished finish.

This invention accordingly eliminates the die cutter Celluloid tracing, the mechanical indexing of the roll, the sharp cutting edges, the expensive hand tooling of an entire roll, as well as the off register of slippage in hobbing. It is a process for obtaining accurate registration of mated male and female steel embossing cylinders or female or plain steel coining cylinders operating with inline printing cylinders for register printing and embossing operations. In short, this invention is a method of obtaining accurate registration of matched hardened steel embossing or coining cylinders to printing cylinders in inline operation, and the embossing or coining rolls of this invention are particularly useful in the continuous register embossing or coining of multi-color labels, wraps, cartons, and containers of plastic, metal or paper foil or cardboard.

Turning to the drawing and to FIG. 1, the Web of a metal foil-coated roll of label paper 11 is disposed through a first conventional color applying roll set 12, for example, for printing the red design features of the master art work on the web 10 then through a second conventional color applying roll set 13, for example for printing the blue design features on the web 10, next through a. third conventional color applying roll set 14 for example, for printing the green design features on the web 10, and lastly through a pair or end set of matched embossing rolls for adding the embossed design to the web 10.

The color sets 12, 13 and 14 consist of a top printing roll and a bottom back-up roll such as are conventionally used in multi-color printing of a web 10 with a vast number of labels. Where a conventional set of matched steel embossing rolls 15 are employed made by conventional acid etch procedure the female or top roll has undercut edges on the embossing pattern due to the acid action on the steel roll. The conventional female or top roll upon mating with the bottom male roll often cuts the web 10 thereby mutilating the multi-colored embossed web so as to make it worthless. Moreover, because of the drag due to the undercut edges of the conventional embossed rolls 15 the web 10 is pulled out of register so that the embossed pattern will not be centered or mated with its co-acting printed patterns of color rolls 12, 13 and 14.

According to this invention, the undercut edges of the female production roll 15 are eliminated and exact register of the embossed pattern with the color patterns is always maintained.

The register of the embossed and color patterns according to this invention is due to the use of separate identi cal films of a correspondingly blanked out master art work to produce respective films used to make the color applying sets of rolls 12, 13, and 14 and an embossing film 16 for applying an embossed design upon a previously made multi-colored design made by the use of an identical master design.

But before the production embossing rolls having a vast number of repeat embossing designs of the label can be made, it is necessary according to this invention, to make a pair of special matched steel mill rolls having one or a few repeat designs using a strip from the embossing film 16 after the female embossing roll 17 has been photo-engraved from said embossing film.

The manufacture of a conventional film having a vast number of repeat designs of a selected portion of a master art label FIG. 3, accurately disposed thereon by conventional machine repeat apparatus, is old in the art.

Such a film is wrapped around and secured to a suitable roll upon which conventional Eastman Kodak photoresist composition 18 has been sprayed. Next the roll is rotated under ultra-violet light thereby exposing selected areas of the resist composition 18 to said light. Then the film 16 is removed from the roll and the exposed resist is conventionally Washed in a liquid to remove the unexposed resist thereby leaving a pattern of the label on the treated roll. This pattern on the roll is then conventionally acid etched to a depth of about 0.001 inch and used as such as selected color rolls 12, 13 and 14 depending on the color retained by conventional camera staging to make a respective film for applying a respective single color.

According to this invention, a single repeat design or single strip of several designs taken from the embossing film (FIG. 2) is disposed upon conventional Eastman Kodak photo-resist composition on a steel mill roll 20. The process of exposure to ultra-violet light followed by washing out unexposed resist and etching is repeated exactly as for making the respective sets of rolls 12, 13 and 14 for printing respective colors, for example, red, green and blue.

The mill roll 20 having the about 0.001 inch deep label pattern of the embossed design is then hand engraved, giving a female mill roll 21 having rounded edges. Next, a male mill roll 22 is made by conventional means using asphalt-urn acid resist composition followed by etching with conventional ferric chloride etching solution to give a matched steel male mill roll 22 having rounded protuberances 23.

Clearly the hand engraving of mill roll 21 is expensive so that if the embossed pattern is intricate only one or two repeat label designs are disposed on a mill roll 20. However, where the embossed pattern is very simple, many repeat designs may economically be photo-engraved upon and then hand engraved on a female mill roll.

Alternatively a female hand engraved steel mill roll having a single repeat design may be used to make a male steel mill roll having many repeat designs thereon.

Having now a pair of matched mill rolls having a deep embossed pattern, the next step is to make a pair of matched production embossing rolls having a large number of like deeply embossed patterns. To accomplish this effect, the male mill roll 22 is contacted to a prepared cylinder 17 having a photo-engraved embossing design thereon, from the corresponding embossing film 17, of about 0.001 inch deep obtained as previously described. By use of successive repetitions of asphaltum resist composition, followed by contact with the male steel roll 22 to expose bare metal, and then treatment with conventional acid etching solution, a female production roll 15X (FIG. 8) is obtained having rounded edges, FIG. 10, and having a depth of 0.015 inch.

A male production roll 15Y is made from the female production roll 15X by conventional procedure using repetitions of the asphaltum. resist coating, contact and etching step outlined above in making the female production roll from the male mill roll.

After making the matched pair of embossing rolls 15X and ISY they are disposed in a conventional high speed rotary printing press as the end set of rolls 15 to print a plurality of labels having multi-color and embossing designs thereon.

This invention has been illustrated by several embodiments but clearly it is not limited to its illustrations.

Thus, for example, the embossing design may be superimposed upon a color design or a portion thereof, such as the red design.

I claim:

The process of preparing a pair of mated male and female embossing steel rolls for obtaining accurate reg istration to mul-ti-color printing cylinders having a plurality of identical designs thereon for inline operation of said printing and embossing rolls comprising photoengraving a large soft steel female embossing roll with a large number of identical designs from an embossing separated photo-composed film to a very shallow depth, removing at most a small number of designs from the photo-composed film, photo-engraving a small soft steel female roll using said removed designs to substantially the very shallow depth of the large soft steel roll, hand tooling the photo engraved design on the small female roll to the full embossing depth with formation of rounded edges on said designs, heat hardening said small female roll, hob-etching said hardened female roll into a mating small male roll to efiect a full embossing depth, heat hardening said small male roll, contacting said large soft steel roll with its shallow designs in register with the protuberances on the hardened small male roll to deepen and contour the etched plurality of designs thereon to full embossing depth, heat hardening said large female steel embossing roll, hob-etching said large hardened steel female embossing roll into a soft steel large male embossing roll to full embossing depth and heat hardening said large male embossing roll thereby producing a pair of matched hardened steel embossing rolls mated accurately to the printing rolls for inline operation.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Hackleman: Commercial Engraving and Printing, 1921, Commercial Engraving Pub. Co., Indianapolis; only pp. 593 and 594 made of record. (Copy available in Divi- 20 SiOn

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