US1752298A - Printing die - Google Patents

Description

4 April 1, 1930. F. GREFFIN 1,752,293

PRINTING DIE Filed April 6, 1927 l 7m/enfer Pff/L /P GREFF/N 5'@ @MMM TTOENEYS Patented Apr. 1, 1930 .UNITED v'erlrxriis ATENT FFEUE PHILIPP GREFFIN, OF MINNEAPOLIS, MIJ'JBTESOTA,V ASSIGNOB. T0 MELONEBOVEY LUMBER CO., OF MINNEAPOLIS, MINNESOTA, .A CORPORATION 0F MINNESOTA PRINTING DIE Application inea April e,

This invention relates to the art of embossing and printing, and particularly relates to that section of embossing art concerned with pressure work through sheet material, with male and female dies -engaging the sheet from opposite sides. The invention is based on the discovery of a new use of a known material, principally for the purpose of producing what is known in the embossing art as the male die. However, the invention is not considered to be limited tothe production of male dies, sincethe material possesses qualities permitting of use in any Work where it is the object to compress certain portions of the material and cause other portions to be raised, to provide a printing plate or die. no claim is made for the production ofthe material but only to the discovery of a new property in the material by which it may be used for the above mentioned purposes.

The main object'of the invention is to provide a. material which, when acted on by a die, will receive and retain an impression in relief, in which the raised portions are of suflicient and of Vequal height to produce what is known in the embossing art as the male die, and to produce such a die 'having suflicient rigidity to withstand the unusual and pro-Y longed friction and compression strains well known in this art, and yet to provide. a die having those qualities which enable it to also act as a cushion. p

In order to clearly show the economic value of the discovery of the properties ofthe herein described material, as a medium for the taking of embossed designs, a, presentationr of the method now in general use, is given. In the oldprocess some sort of binder board or other suitablematerial was used as a base for the male die, and this base was overlaid with sheets of paper superposedl one after the other'to buildup the design upon the base. Thus in the original process, the operation was mainly that of building up. This operation was performed inthe following manner :A metal or female die was prepared having the desired design. The next `step was to form the male die. For this purpose, a base was selectedand upon this base was It is to be understood thatl 1927. Serial No. 181,450.

first secured a piece of paper of suliicient raised design. This was a very expensive, f

time-consuming process..

It vwill be seen that the difficulty encoun`` f tered in this work is to produce raised portions of sufficient height andto have all raised portions of proper height. In addition it has been difficult to lind a material' upon which such raised portions could at all be evenly produced, and in whichthe raised portions were rigid enough to ywithstand the hard usage to which the dieis put. Itwill be understood that the operation vof kbuilding upv and re-impressing is very ytime-consumingv and expensive andit is the object of this invention to eliminate the necessity for vthese operations.

To further show the economic value of my discovery a kind of history of my own experiments is given. As above stated, orig# inally book binder board was used. This hoard is composed generally of fibrous woody material such as wood pulp. The attempt was made to produce the raised or embossed portions by a single, prolonged impression from ya metal die. rrIt is evident that. if such a thing could be done, the building up operation could be entirely dispensed with. l ,How-` ever, in all the materials experimented withv except the one described herein, .raised por..

tions of proper definition and heightcould not be produced except by Lbuilding upin the manner' above mentione Attempts lwere made to formthe diein another manner, to-wit: by making the impression in plastic material held upon, a suitable Vbase, for example both cement andsealing wax were used.' When usino-fthesesub= stances, a suitable base was providedlandiwas over-laidv with a coat or layer of the sublil() stance, andthe impression was made while in a plastic state. However, 1n these eases 1t was practically impossible. to obtain an even spread, that is one having equal thickness at all portions. `Moreover, in both cases the coating would crack under the ordinary working pressures. Thus the obgections were,

poor denition in the embossed areas, andV fracture of the die under pressure. More success was had with cement in regard to the evenness of the spreadf but the substance was too brittle to withstanc pressure. lvloreover, although the bases were generally formed of compressible material, this did not prevent cracking of the surface coating.

Experiments were made with another material called bakelite. Sheets of this material were used having a thickness of about onesixteenth of an inch. However, this substance was of such density that sufficient clearly defined embossed areas could not be obtained.

Y Moreover, the embossed portions were of uneven height. This material, also, broke down underl pressure, so that a very small number of impressions could be made before the die was rendered useless. The length of life of thel die could not be depended on as evidenced by the fact that one might only obtain from five to sin impressions. There was always the uncertainty as to whether the die would last until their-run77 was completed. Therefore, with using' the above materials, it was practically impossible to obtain clear definition and when some degree of uniformity or clarity was obtained, the substance would 'crack under pressure, r

Various so-called builder board materials werealso tried but all were brittle and acted under the ordinary working pressures, something in the manner of dry lime, that is, they crumbled. The results were fracture, lack of clean definition and lack of sufficient height of the embossedV areas, and uniformity of design, as Well as failure to retain the impression. Y r

Another board was tried which is also a pulp board but the materials are ground and kthe fibre did not have sufficient tensile Lil to me which will unfailingly g fined embossed designs of even height and sufficient rigidity, as a result of'a single impression without building up.. Moreover, the

rive clearly dematerial is of even texture and can be successfully carved, that is, without splitting and chipping and without unduly dulling `thetools.

A material for use as a male die forthe purpose Vmentioned above must have a medium length, strong fibre which is sufficientiy long to make the material tough and to cause it to hold together when beingv cut. After a large number of experiments-it appears that the material must also have along line fibre well interwoven in the manner of a felt. Felt itself, however,-is too soft, and does not-,possess sufficient rigidity, nor will such material retain the impression.

The material which l have found to be the best is made from yellow pine inthe following manner: Edgings from yellow pine saw mills containing live material and no bark, is cut into blocks approximately two inchesV square. These blocks or chips are then loaded into what is known as a gun, and are submitted to a steam pressure ofY about twelve hundred pounds. The steam carries o some of the resinous material but leaves sufficient of natural resinous wood Abinder to obtain a tough comparatively soft and ycompressible material which can be out `without breaking or cracking. Thus theV natural binding quality of the wood is takenadvantage of and sufficient resinous mattei' is provided so that each libre is coated with such binder. After the chips have been submitted to the pressure above mentioned, vthe gun is shot to release and explode the moistened material producing the fine fibre resembling fine cut tobacco; This `material is then heated and compressed to form the sheet material, having substantially the properties above described. K

The drawings illustrate the method of making the male die, and this illustration is only suggestive of .theuse of the present material for the purpose of making dies orplates for use in the embossing and printing arts, Y Figure l is an edge view of a sheet of material from which, in this instance, a male embossing die is to vbe constructed; Figure 2 shows the female die making-an impression in the newly discovered material; This being the f ust step in the preparation ofthedie; n Figure?) is an enlarged view of the .die after the impression, represented in `Figure 2, and

shows the coating of hardening material` f placed on .the die after impression;

Figure 4 is similar to Figure 3 but shows the addition of asheet of pap-er over-lying and adhesively secured .to the hardening coat. This figure represents thecompleted male die; andV Figure 5 illustrates the operation of the press showing the male and female die cooperating to produce an embossed designupon a sheet of material. A Y

The numeral l indicates a sheet ofthe material herein described, or material 'having similar qualities. The numeral 2 indicates a metal die, in embossing Work designated the female die, produced in any suitable manner. This die is suitablyl mounted so that pressure can be applied. Figure 2 shows the first operation Which is to make an impression on the material to form the male die. Figure 3 shows the die after being impressed by the metal die 2, and the numeral 3 designates a brushed-on layer of hardening material, such as Varnish applied directly to the impressed and embossed surface, and to better enable the raised or embossed portions to stand up under use. lt Will be noted that With the material having the qualities set'forth herein, uniformity of design can be produced, by a single impression. It Will be further noted that heights exactly corresponding to those of the metal die are produced, and that, therefore, no building up of the raised portions or any of the impressed part is necessary. lt Will be further understood that in a given design some parts are given a greater embossed height to accentuate those parts. lt has been found that all of these resultsmay be obtainedby a single impression.

Figure 4 shows the completed die in Which further reinforcement is provided by means of a sheet of ordinary Wrapping paper 4. rfhis sheet is adhesively held and to the coated surface, and in addition to reinforcing the embossed portions, it prevents lpossible contact between the sheet to be embossed, and the hardening layer. lt will thus be seen that as thev result of feW simple operations, the main one of which is a pressure operation. a male die or impression plate is produced in which proper heights in embossed areas are had, and in Which the embossed portions yare reinforced to With-stand the unusual pressures of the modern presses. The pressure applied is about twenty tons and the length of the impression from tvvoto three seconds. @n the old presses, the pressure was substantially instantaneous, and it Was found that With the substances like builders board, cel ment or bakelite that theproper impressions Were seldom, if ever, produced. It has furter been found that if the pressing operation is continued, as in the modern type of press, that the same difliculty is encountered, that is uniform embossed designs ofthe proper height are not produced Without subsequent impressions and building up with paper or other suitable material. With the material herein described every portion of the design is Vproduced in a clean, Well defined manner,

. and Well raised embossed effects are always forthcoming. The material is very cheap, but the cheapness of material is a small item as compared with the time saved on the building-up operation above mentioned. f

Figure rshovvs the operation of producing an embossed vrdesign on a sheet of suitable mabossed.

' It will be understood from the description that the properties discovered in the material n described, as the result of which the material will take the impressions in the manner above set forth, form the main features of my invention. ift will be understood, however, that l believe myself to be the first to form a die of the character described which is composed of a single thickness of fibrous material of homogeneous consistency and having a comparatively long Well matted together fibre. Some of the'knoivn and essential properties necessary for the use set forth herein are: sufficient length of fibre, a natural resinous binder, combined With a certain density arrived at by compressing the material to a predetermined extent. `lidoreover, I believe myself the first to make a die of the character described composed of a single thickness of ymatted, compressed cellulose material, the

fibres of which are tough and of medium length. Moreover, evenness of texture is necessary.

Furthermore it is to be understood that by using the material having` substantially the qualities herein set. forth, much Wear and tear on the press is avoided, vbecause no building up operation is necessary. It Will be further understood that in the building up operation, as When paper is used and asv before mentioned, the original impression havingibe'en made and a sheet ofinate'rial having been laid thereon, a number of successive pressure` movements Were necessary in order toAV depress certain portions and raise other v.portions yof the over-laid sheet of' paper, Itvvas necessary to make these impressions several times for each overlay. Thus it can be seen what a great saving is made both in the matter of time and in the Wear on the press.y by being able to obtain a die With asingle impression. l claim as my invention:

A dieconstructed from a material composed of exploded and matted togethervwood fibre. r i

2. 'A die constructed from a material com-'v posed of exploded and matted together pinek Wood fibre.

3. A die constructed from a material com-i'V y posed of exploded and matted together live yellovvlpine libre.

4. A die constructed from a material composedof exploded'and matted together Wood fibre, the fibre being comparatively long and tough and containing a large proportion of f its natural resinous matter.

5. A. die constructed from a material composed of exploded yand matted together yelloW pine Wood fibre, the fibre being comparalesY Y tively long and tough and containing a large proportion of its natural resinous matter.V

6. A die constructed from a material comprising yellow pine fibre in Which the fibres have been exploded and matted together andv in which the libres contain natural resinous Vmaterial as a binder, the said material after explosion having been heated and compressed.

7. A die constructed from a material comprising live pine fibre in Which the fibres have been exploded'and matted together and in which the fibres contain natural resinous material as a binder, the said material after explosion having been heated and compressed.

8. A die constructed from a yieldable Inaterial and comprising a tough Wood fibre matted together. Y

9. A die constructed from compressible material comprising Wood fibre in which the iibres have been exploded and matted together, and in which the fibres retain the natural resinous material as a binder. Y

l0. A die constructed from a compressible material consisting of relatively tough libre matted together and in Which the fibres retain natural resinous material as binder, the said material having been heated and compressed to form a sheet.

11. A die constructed from a yieldable material and composed of a tough, comparatively long Wood fibre matted together.

l2. A die having a base composed of a single thickness of librous materia-l, said die having an embossed surface, and having a coating of varnish-like material over this eml bossed surface, and further having a sheet i v my hand this 29th of paper over-lying and adhesively held by the varnish-like coating.

.13. A die having a base composed of a single thickness of fibrous material of homogeneous consistency, said die having'l an embossed surface, and having a coating of varirish-like material over this embossed surface and further having a sheet of paper overlying and adhesively held by the varnishlike coating. V 'Y 1 In Witness whereof, I have hereunto set day of March, 1927. PHILIPP GREFFIN.

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