US1377501A - Method of making printing-plate matrices or molds - Google Patents

Description

EA E. NOVOTNY.

METHOD OF MAKING PRINTING PLATE IVIATRICES 0R NIOLDS, ISIC.

APPLICATION FILED MAY 2o, ISIS.

1,377,501. Patented May 10,1921,

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EMIL E. Novo'rNY, 0E RIVERSIDE, ILLINOIS, AssIGNoR To J. s'roGDELI.

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METHOD 0E MAKING PRINTING-PLATE MATRICES 0R ivIoLDs, ae.

Specification ofgLetters Patent.k n Patented Igny 10, 1921.

Application, filed May20, 1916. Serial No. 98,905. i i

To all whom 'it may concern:

Be it known that I, EMIL E. Novojrir, a citizen of the United States, residing at Riverside, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Methods of Making Printing-Plate Matrices or Molds, &c., of which the following is a specification.

This invention relates to the manufacture of molded printing plates.

ln practising my invention I followsuch a method that the matrix or moldwhen completed will so embody the essential factors of exactness of form and accuracy of dimensions and the duplications of working surface regularities and irregularities comparable with the original properly proofed type matter used in making the mold that the printing plates duplicated or produced through the agency of this mold willV require but a minimum amount of make-.ready when applied to the printing press. In other words, all of the various inaccuracies, faults and errors both of the type matter itself and the particular printing press upon which'the plate is to be used may be taken into con-A sideration and compensated for in the mak-v ing ofthe matrix or mold, thereby substantially eliminating the element of make-ready in connection with the plate usually neces*-y sary to assure uniform printing.

As is well known in the printing art there are a number of factors which necessitate 'following out a tedious and expensive makepression cylinders orV platens, andlother ele-v ments of error affecting the'uniformity `of impression of the type body or plate, which are well known and recognized by printers Aand pressmen, and which require considerable make-ready to eliminate. In addition to these defects peculiar to the body ofthe type or plate there-are the structural defects f ing jv `portions therebetween.

plate of unusual strength results.

'cially jisthisthe case where the` cast plate in its'finalvform-is coinposed,-as is preferable. Y

and inaccuracies of the printing press itself .to be considered, and each style and make of press, such as the bed and platen type,

:exemplified for instance by the Gordon press, the bed` and cylinder press and the vrotary'press has its own peculiarv and particulardefects which must be taken into consideration and compensated for by the pressman through the medium of a laborious and tinie-consuming procedure of make-ready.

L *My present invention is applicable to the production of molds for making two styles `or classes oflplates, that is to say, flat printing plates to be used upon printing presses [having substantially flat beds upon which the plates are mounted, and curved printing platesy for `rotary presses 'employing cyl- -vinders yupon whichvthe plates are carried, and a ,matrixV- or mold made by my method willvproduce printing plates of either style characterized by great strength andr durability coupled' with sharpness 'and trueness of outline and accuracy of dimensions and *which will require but little or no makeready work on the part of the pressman,

thus accomplishinga Saving of time,labor and.y expense. n p Furthermore, both the matrix or mold and the plate produced thereby will have those yportions of the face which offer no printing surfaces so formed' as to provide `depth without abruptanglesthus giving to the 'printing surfacesv or type portions fine lines, and stable, rigid footings or bases.

@' Ihe mold produced by method is pref- `erably`made` of lead ora composite body containing lead as this is an ideal inetal'for 'my purpose inasmuch as it possesses plasticity with-ibutflittle ductility, and consequently when under pressure or heat and pressure, in contact with a body of original type niatterin a chase, the metal will flow in such manner asto produce sharp glossy typeface-molding portions with well rounded, swelled or curved non-type-face form- Consequently a printing plate cast in such mold .will possess fine, sharp' clear type faces surmounting broad foot sections or bases tapering.. and widening as they approach and merge intothebody of the plate so that a 4Espe- Vas usual for composition errors, such as be subjected to both heat product, such as that called bakelite, or theV like.

In the accompanying drawings:

Figure l is a View showing a simple form of apparatus for making my mold and showing the mold sheet therein.

Fig. 2 is a transverse sectional view showing the mold sheet after ithas been subjected to pressure with a yieldable backing sheet imposed on the mold sheet.

Fig. 3 is a similar view taken through the mold sheet after it has been subjected to another pressing operation in conjunction with a. resilient backing sheet or blanket.

Fig. Li is a transverse sectional view of a completed mold after it has been leveled by shaving, or otherwise. Y

Fig. 5 is a transverse view through a conventional form of casting box and showing a printing plate being made with mymold.

Fig. 6 is a transverse sectional view through the completed printing plate, in this instance a flat plate.

Fig. 7 is a similar view through a curved or partly cylindrical plate.

Figs. 8, 9 and 10 are sectional views diagrammatically illustrating on an exaggerated scale the madeready printing surface of the original type body; the facsimile mold Ysurface produced therefrom and the duplicate positive plate surface produced by the mold, and showing the exact-V ness of similarity existing between the same. In the present instance I have, by way of illustration, Vdescribed the mold as made under pressure from a single sheet or plate of metal, such as lead, but in this connection I wish to state that the mold may be made from various materials and combinations of materials, such for instance as form the subject matter of copending applications Serial NOS. 98,908, 98,907; 99,908; 98,909, all filed May` 20, 1916; and furthermore that the mold in the course ofmanufacture may and pressure, if desirable. Y

Therefore this invention deals broadly with the production of a new printing plate and a mold or matrix therefor, produced by a'novel method all to attain the ultimate ends set forth herein.

The mold.

The original type matter which is shown at A, is first set up in the chase B andthe usual preliminary proofs taken on a proofing press which has been preferably standardized and made ready for its own errors.

The preliminary proof is ofcourse checked 1 spelling, punctuation, etc., and when correction'has beenlmade in this respect further proofs are taken, and studied for inaccuracies in helghtto paper, printing pressure and the like. Suitably make-ready Inaterial C is now placed beneath the type to compensate for various other errors or defects such as variations in height to paper of differentV sections or areas of the type body, the diference in thickness'between the proof paper and the paper to be printed upon, difference in printing pressures required and other similar matters well known to printers and pressmen, and dealing particularly with the rectification of the type body. When the final proof sheet shows uniform and satisfactory impressions this properly proofed body of original type is readyfor the mold making operation. This body of original, proofed type is now placed on the bed D, of the press E, of any suitable character, and which press in the present instance includes a reciprocating block or platen F. By means of this pressrthe mold or matrix may be subjected to pressure for the purpose hereinafter described. -The sheet or plate from which the mold is to be made, is in the present instance composed of a single sheet 0f cold lead of suitable thickness and is shown at G. I t will be understood that in this instance the cold lead sheet is to be subjected solely to pressure', but if desired may be in some cases subjected to both heat and pressure, and instead of a single lead sheet, other forms and compositions of sheets may be used.

vThe single lead sheet employed may be of a thickness of .080, for example, and thisV sheet placed on the body of type. Upon the chase Y, preferably at the longitudinal sides thereof I mount a pair of bearer bars H which are ofsuch height or thickness as to accurately limit the downward movement of the movable platen F of the press, so that the proper pressure willbe applied to im press the type intok the lead mold sheet the required depth as the platen will be limited in its downward pressing movement by con tact with the vtop of the bearers.

Upon this cold lead sheet Gr I may now place a sheet or sheets of material having yieldability, but not flexibility, such for example, as newspaper sheets shown at J and now operate the press to subject the lead mold sheet to its initial or first pressure. Theplaten of the press is now moved into contact with paper covered mold sheet and the pressure applied until the press platen preferably contacts with thetop of the bearer bars, thuspressing the type faces of the body of type into the lead mold sheet. In some instances one operation of the press may be sufficient to produce" the proper type forming depressions in the mold sheet, but it is preferable in many cases to repeat this pressing operation one or more times and with each successive pressing operation an additional layer or sheet of the yieldable backing such as the newspaper is added and used. These successive impressionsv result,

in the gradual formation of kthe type depressions without excessive pressure at any one operation. I use a backing sheet, such as newspaper, because it is what I consider as a yieldable as distinguished from a resilient backing such as I subsequently employ as hereinafter described, this yieldable backing enabling me to obtain the proper type-forming depressions in the mold sheet without altering the non-type forming surfaces of the mold sheet, such alterations of the non-type forming surfaces taking place when a resilient backing is employed in that step of my method which I will now describe.

After the pressing operations with the yieldable backing have been completed, and the type depressions of requisite depth and sharpness formed in the mold sheet, I substitute for the paper backing, a resilient backing sheet or layer, preferably of rubber or any other material possessing-the necessary resiliency and thickness, as shown at K. The pressing operation is now repeated with the result that the face of the mold is formed with the swelled or curved non-type forming portion 2, adjacent or surrounding the type-forming depressions. These swelled or curved portions of the molding` face of the moldresult because the'backing sheet having the quality of resiliency, under the action of the press pushes outward or downward against the portions of the lead sheet not held or suspended by the impressed type-faces, and consequently imparts a bulging, swelling or curving effect to such unsuspended portions. Whenethis step of the method is completed the molding face of the mold will be a reverse duplicate of the face of the type body, that is to say, will embody, with exactitude all the printing regularities and irregularities existant in the original vtype-body with its make-ready.

The back of the mold` sheet may now be planed and shaved so that the back of the mold will present a uniform level surface, and there will exist a substantially fixed depth or thickness of material between the bottom of the type depressions I and the back of the mold. I use the word substantially because there may, and probably will, exist slight variations or differences in this depth or thickness in different parts of the mold, due to whatever make-ready andy other regularities are used.

rIhe type depressions penetrate the lead mold sheet preferably to substantially the central horizontal line of the latter, that is, go half way through the mold sheet, because in using the mold for the casting of curved plates the mold must conform to the curvature of the female portion of the casting box, and as the convex portion of the mold rrieties known in ythe art.

portion subjected to shrinkage, Athe central portion or type'depression level will beat L a substantially yneutral point,y eliminating shrinkage or stretch to kthe type matter due to the curvature of the mold. d

The" plate.

employed in casting a plate made vof anyl suitablematerial, it is especially well adapted for thefmoldingofja plate composed of a phenolic condensation product or composition of which there are a number of va- Such a phenolic product, which as is well known is a synthetic resin, usually has as constituents phe-l f nol and formaldehyde, and alprinting plate made of'this class of material possesses manifest advantages, inasmuch as being a plastic` material at. a certain stage it is 'capable of 'faithfully yreproducing the regularities and irregularities which are required in aprinting plate, thus insuringfan exact negative reproduction of delicate outlines and levels of the mold. #It also produces aplate having :y durability, rigidity, stability and uniformity under variations vin temperature, rand one which will withstand the stresses and strains encountered iny the printing operation, and'y .will present sharp, clear type outlines, thus insuring clear, attractive work.

I take a sheet or portion of this material in its unset formvin which itis commercially marketed, such sheet being of approximately the area', but of slightly greater thickness than the plate to bemade, the extra thickness allowing for compression. Thissheety is heated Vat a temperature for example -of from 200 "to400 Fahrenheit to render it the bedof the "casting box L and within the frame 1 of the box which predetermines the size of the plate, this frame 1 may be v formed to casta plate with beveled edges. The mold is clamped in position, ,and the mold and casting box heated. The top `M of the castingbox is also heated, the casting boxhaving previously been coated interiorly with a weak, soapy solution, preferably of Turkey red oil and water to prevent the plate composition sticking to the casting box. The plasticmaterial for the plate shown at O is placed on top of the lead mold, the top part of the casting box placed in position, and the vassembled casting box placed in ak heated press and subjected to slow pressure to completely close -the'casting box and retain it in that position, subjecting the plastic material toboth heat and pressurey for a suitable length of time, depending on the degree of hardness of. platel desired.y For instance, the plate may be subjectedr to heat and pressure for from 'one to` twenty minutes at a heat of from 200o to 400 Fahrenheit.Y This is merely illustrative. The casting box is provided with :suitableV vents P, which are small enough so the pressure is not greatly reduced, but large enough so that any excess of plastic material may escape from the casting box. The plate O is preferably cooled under pressure either by transferring to another previously cooled press or by cooling the same press. The mold and plate are then removed from the casting box and the plate separated from Vthe mold, and is now complete and ready for use as a flat plate.

If a curved plate is to be made sucha plate shown at Y in Fig. 7 may be formed in several Ways. For instance, by taking a plate which has been impressed in a flat i mold, but only partially hardened and cooled Or the casting box and the mold mayV be made concaved and the plate cast therein.V

Vhile I have herein shown and described by Way of illustration certain preferred forms of the invention, I Wish it to be unthe precise detailsV herein set forth, as modiications and variations may be made Without departing from the spirit of the inventionor exceeding the scope of the appended claim. Y

What I claim is:

The herein described method which comprises'applying a predetermined amount of make-ready material to a type body tov insure correct printing planes for the latter, then imposing a metal sheet upon the corrected type face of the type body and applying pressure to form a matrix having a metallic molding face which is an exact reverse duplication of the printingplanes of the type body, as corrected with the makeready, then removing the matrix from the typebody and imposing upon the molding` face of the matrix a body of synthetic resinoiis material capable of assuming a hard, set and infusible form when heated to a predetermined degree, and then subjecting Athe synthetic resiiious body toheat and pressure against the matrix to form a hard, set and iiifusible printing plate having printing planes corresponding to the corrected print- Yingplaiies of the type body.

In testimony whereof I affix my signature.

, EMIL E. NOVOTY.V

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