US2133981A - Printing element and method of making and using same - Google Patents

Description

P. A. FRAZIER PRINTING ELEMENT AND METHOD OF MAKING AND USING SAME Filed March 29, 1935 Iraq grim? raz bar Patented Oct. 1938 1 UNITED STATES PRINTING ELEIVIENT AND METHOD OF MAKING AND USING SAMIE Philip A. Frazier,

Oak Park, 111.,

assignor to Frazier Processes Incorporated, New York, N. Y., a corporation of New York Application March 29, 1935, Serial No. 13,629

12 Claims.

My invention relates in general to the art of printing, and more particularly to that phase of printing concerned with the mounting of the printing element.

5 The invention has, for an important object, the

provision of novel means for and method of supporting a relatively thin printing plate, such as the electrolytically deposited shell commonly used in making up an electrotype, in position to per- 10 form its printing function in such a way that the lands or high spots of the plate, which accomplish the printing by applying ink to the surfaces being printed, are supported relativelymore firmly and rigidly than are the valleys or low 15 spots of the plate, to the end that the printing may. have sharp definition between the inked spaces.

Another important" object is to provide for mounting a thin, shell-like printing element, such 20 as is used in electrotypes, yieldingly in printing position, the plate being yieldingly supported throughout its entire area, whereby printing pressure between the plate and the surface being printed may be substantially uniform throughout 25 the area of the plate, to the end that the resulting printing is of uniform texture.

Another important object is to provide for backing a shell-like printing plate with resilient material, such as rubber, to improve the printing characteristics of the plate; a further object be,- ing to apply the rubber in substantially raw condition in order that the same may flow into the crevices in back of the plate so as to provide a backing at all points within the area of the 35 plate, and then vulcanize the rubber in order to cure and solidify it in place.

Another important object is to provide for vulcanizing the rubber backing to 'diiierent' degrees of hardness in order to afiord greater support 40 behind certain portions of the plate while permitting other portions of the plate to yield when printing pressure is applied.

Another object is to provide for mounting a printing plate on a rubber blanket, which con- 45 sists in printing a sheet oiuncured rubber with a suitable adhesive in accordance with the design oi'the printing plate, dusting the printingsheet with a .rubber vulcanizing medium sueh as 8111- phur, mounting the plate on the sheet so that the "5o dusted'design onthe sheet registers with the corresponding design of the plate, and then vulcanizing the sheet in place so that the dusted portions, which are behind the lands orhigh spots of the plate, become harder than the adjacent 55 portions of the sheet as a result of the vulcanizing process and thus furnish a greater degree of support behind the high spots or lands of the mounted plate, to the end that the mounted plate is adapted to provide a substantially uniform impression in the printed areas despite slight inaccuracies in the press in which the plate is used and without make-ready, that is to say, the accurate adjustment of all of the high spots of theplate with respect to the press.

Another important object is to employ a resilient medium, including metal, as a backing for a shell-like printing plate.

Another important object is to utilize a mixture of latex and a metallic flour to form a resilient backing for a shell-like printing plate.

Another object is to provide a backing tor a shell-like printing plate by applying a metallic medium on the back of the shell to a depth suflicient to fill the depressions, then shaving the backing medium and applying a resilient medium behind the shaved material in order to provide a resiliently mounted printing element.

Another object is to back a shell-like printing element by spraying a metallic backing medium upon said element.

Another important object is to provide a backing for a shell-like printing element by spraying the back of the shell with liquid latex and then curing the same in position on the back 01' the shell.

Another important object is to provide for printing with an element including a printing face formed by electrolytic deposition, which consists in applying resilient means behind said element while a print is being taken.

' Another important object is to provide for backing a sheli-like printing plate with resilient material, suchas rubber, to improve the printing characteristics of the plate wherein the resilient material is hardened in certain areas to 40 a greater degree than in other areas whereby to afford greater support behind certain portions ot the plate; a further object being to harden the rubber by difierentially curing the same.

Another object is to accomplish the diflerential curing of the rubber by applying a medium adopted to accelerate vulcanization in those areas of the sheet where greater stifi'ness is required.

Another important object is to accomplish dif- V ie rential hardness in the finished product by partially pre-curing the rubber at the places where additional stiflness is required as by exposing the sheet to heat or other rays through a screen.

Another important object is to accomplish differential hardening of the rubber sheet by printing the same with latex ink at the places where additional hardness is desired.

Another important object is to provide a curved printing element having improved printing characteristics.

Numerous other objects, advantages, and inherent functions of the invention will become apparent as the same is more fully understood from the following description, which, taken in connection with the accompanying drawing, discloses a preferred embodiment of the invention.

Referring to the drawing:

Figure 1 is a perspective view of a relatively thin printing plate and resilient mounting layers, the parts being shown in exploded or disassembled relationship;

Figure 2 is a perspective view of a printing plate mounted in accordance with my present invention;

Figure 3 is a vertical section taken substantially along the line 33 in Figure 2 and Figure 4 is a similar section illustrating a modified form of the invention.

It has long been apparent that the most satisfactory printing surface for letter press and other commercial printing is provided by the electrolytically deposited copper shell commonly used in the fabrication of electrotypes. The copper shell is comparatively thin and flexible and requires support means to maintain the same firmly in place in order that the same may be used as a printing element. Such a shell is ordinarily finished by backing the same with a layer of usually metallic material, such as lead or a suitable alloy, after which the electrotype is finished by bringing all of the high spots of the plate into a common plane, which is exactly parallel with the back of the electrotype.

My present invention relates more especially to improvements in the backing of shell-like elements in the provision of electrotypes and, in general, comprises the application of a resilient backing on the shell to the end that the printing surface of the same is rendered self-aligning during the printing operation, whereby the finishing of the electrotype to bring all of the high spots of its printing surface into alignment does not require particular accuracy, care, or skill so that the labor and cost of providing a mounted printing element in accordance with my present invention is considerably reduced.

I accomplish'these advantages by backing the printing plate with resilient material, such as rubber, in order to obtain a printing element having all of the qualities of an electrotype and, in addition, the advantages of a resilient backing,.by means of which the printed impression is of more uniform intensity throughout the area of the element due to the fact that a resilient backing will permit those parts of the plate which are a trifle too high to yield during the printing operation and come into alignment with the other lands of the element. The yielding character of the backing, moreover, permits the edges of the lands, which, in an electrotype, tend to print more heavily than the land portions within the edges, to yield and thus eliminate any tendency toward edge printing.

To illustrate my invention, I have shown on the drawing aprinting plate H mounted on a resilient backing l3, comprising a sheet of special vulcanizing rubber I! which retains its resilience after being vulcanized, and a second rubber sheet I! adapted to become hard and rigid upon vulcanization. If desired, a sheet of woven fabric I! may be interposed between the rubber sheets l5 and I1.

The plate H may, of course, be any relatively thin printing element having a certain degree of flexibility and having the design to be printed formed in the face of the plate. I contemplate particularly an electrolytically formed shell of the character commonly used in the fabrication of electrotypes. The parts are assembled by placing the plate ll face down on a flat surface, such as is provided by a smooth steel plate. The back of the plate, if desired, may be coated with a suitable adhesive, the main function of which is to prevent corrosion of the plate during the curing of the rubber layers. The rubber layer l5, which remains resilient after vulcanization, is placed upon the back of the plate II, and the fabric sheet iii, if used, is superposed upon the sheet I5. Finally, the rubber sheet H, which becomes hard after vulcanizing, is assembled in a stack. The steel support plate may then be placed in a suitable press having a heated head. This head is then lowered into contact with the sheet ll, so that the rubber of both layers l5 and I1 becomes heated and softens to a degree such that the material of the layer l5 oozes into all of the interstices and depressions in the back of the plate if. The two sheets of rubber also become fused together with the fabric I8 therebetween. The function of the fabric is simply to lend strength and rigidity in the final structure.

I may substitute, for the layer II, a layer of any material which may be adhered to the layer l5 during the vulcanization of said layer l5 and which becomes or remains hard after vulcanization is completed. For example, the layer l1 may comprise a metal plate if desired.

After the layer l5 has softened, the heated head of the press is again lowered to squeeze the parts together to the exact desired thickness of the final assembly, and the application of heat is continued until the rubber becomes cured or vulcanized. After that, the press is cooled. The heating and cooling of the press may best be accomplished by injecting steam into the head during the vulcanizing process and then directing cold water into the head in order to cool the same and the rubber. With such an arrangement, but a few moments will be required to properly cool the assembly.

The plate may then be removed and its edges trimmed, as with a saw. The mounted plate is then ready for proofing. No finishing is required, as the plate is finished to correct thickness in the press and possesses all of the finished qualities of an electrotype, since the high spots or lands are in type high relationship with respect to the rearmost surface of the rubber layers. Except for proper line-up in the press, no make-ready is necessary, which results in cutting the idle press time in half. In addition, printing presses of the character having reciprocating beds may be operated at higher speed when carrying the rubberbacked printing plates made in accordance with my present invention, because of the greatly reduced total weight carried in the press, as compared with the weight carried by the press if loaded with electrotypes backed with metal in accordance with prevailing practice.

If desired, a suitable rubber cement may be applied to the back of the shell ll before the layer I5 is assembled thereon, and cement may also be utilized between the layers II, II, and II, if desired. I contemplate also the application of the layer I! as a solution of latex painted, I

sprayed, or otherwise applied directly on the back of the shell ll. 1 I may also substitute resilient material other than rubber for the layer l and any suitable resilient material that can be adhered to the back of the shell may be utilized for this purpose. I particularly contemplate the use of resilient spongy material, which may be made by mixing flour of lead, or of a. selected alloy of lead, with tin and/or zinc and/or antimony with a quantity of latex so that the metallic flour is uniformly distributed throughout the latex. The metal is selected so that its melting point is lower than a maximum temperature permissible in vulcanizing the latex. The solution is applied as a layer to the back of the shell and the coated shell placed in a vulcanizing press, which is operated at a temperature such that the latex is cured duringthe vulcanizing process and the metallic flour is also fused so that, after cooling, a spongelike metallic skeleton frame is formed giriilughout the cured rubber layer behind the I have found that vulcanizing temperatures of from 300 centigrade upwards are desirable because this range of temperatures permits the use of any'well known alloy of lead, tin, zinc or antimony. I have also found that by using a mixture of tin and lead foil in equal parts and vulcanizing at a temperature as high as 390 centigrade, an excellent backing is produced. These examples are given by way of illustration only and are not intended to limit the scope of my invention.

It is desirable to select a metal or an alloy having a melting point somewhat below the temperature applied to the mixture in vulcanizing the latex in order that the metallic conduit may 'iuse at vulcanizing temperatures and form the spongy metallic mass. The selected metal should have a melting point considerably above the temperatures to which the electrotype is submitted in the printing press since it is undesirable to have the spongy mass soften during the printing operation. There are, however, many alloys having suitable characteristics with respect to melting temperatures which may be selected for the purpose, but I prefer to employ lead or suitable alloys of lead; with tin and/ or zinc' and antimony may be added to improve the character of the alloy. It will be understood that the resilient metal and rubber material may be substituted for either or both of the layers l5 and I1.

Rubber-backed printing elements may be made flat, or curved to fit rotary presses, the same procedure being followed in the fabrication of curved plates as heretofore described, except that the'plate and rubber layers are assembled, compressed, and cured between cooperating curved surfaces of suitable shape.

My present invention, of course, applies to printing plates for reproducing type 2| as well as pictures or illustrations 2!. In order to properly print illustrations, it is desirable to provide for greater impression on the solids or high spots 25 than on the low spots or high lights 21. This is usually accomplished on a letter press by means of overlays under the tympan. However, in other presses, and particularly in multi-color presses,

accordance with the teachings of my present invention as a part of the mounting of the printing element ll on'the resilient backing l5. When it is desired to cause any part of the plate to provide for increased impression in any part of the plate as mounted, the face of the shell II, at the places where increased-impression is desired, is treated with a suitable adhesive ink and an impression made upon the underside of the sheet I5, as at 29, before the same is assembled in stacked position on the plate. The printed surface of the rubber sheet is then dusted with sulphur or other vuleanizing medium and the surplus removed so that the sheet l5 contains a layer of sulphur adhering thereto in such a posiharder, as at 3l, than the remaining portions of said layer, so that,'in the finished element, those portions of the plate ii, in which increased impression is desired, are relatively more firmly backed than are the remaining portions of the plate. When a printing impression isv made, the more firmly backed portions of the plate provide increased impression in the corresponding areas of the resulting print.

I may also provide for backing up certain portions of the shell more firmly otherwise than by differentially vulcanizing said parts with sulphur as a vulcanizing agent. For example, I may apply additional strips or patches of relatively hard rubber behind the parts of the shell requiring additional backing ,before. the layer I5 is applied, or I may partiallypre-cure the layer ill by exposing the'same to heat or other rays through a suitable screen formed in accordance with the parts of the shell requiring the additional backing. In this way, those parts of the backing, which are to be assembled behind shell parts requiring additional support, are given a preliminary partial curing so that, when vulcanization is completed, such parts are relatively more firm than adjacent parts and will furnish the desired additional support. I may accomemployed in conjunction with an adhesive ap-' plied'between the shell II and the layer and also may be employed where the back of the shell is sprayed with latex before the layer I5 is applied.

I may also stiflfen the shell prior to the application of the resilient layer "by spraying or otherwise applying a metallic backing 33 on the shell H as shown in Figure 4. Such a backing 33 may comprise an alloy of lead with zinc and/or tin, or any one of said' metals and may be applied to any desired depthupon the back of the shell. I prefer, however, to apply the material 33 on the shell to a depth sufflcient to rather more than fill the hollows behind the high spots or lands 2| and 23.

After the layer 33 has been applied, the backe bring the highspots or lands into alignment on the printing surface of the plate. This process,

however, may be greatly simplified if the overall thickness of the layer 33 is kept relatively small. The finishing operation also need not necessarily be performed with great accuracy since the resilient backing thereafter applied will permit the shell to print uniformly as heretofore described without being carefully finished.

After the finishing operation has been completed, the back of the layer 33 may be shaved down to make the same substantially fiat and parallel with the printing surfaces of the high spots or lands. After this, the resilient layer i5 may be applied. This layer may be of rubber or a resilient metallic material of the character heretofore mentioned. The layer I5 may be applied in any of the modes heretofore described, that is to say, may be applied as a solution of latex, sprayed or otherwise applied, behind the layer 33 and then vulcanized. The layer I! may be applied behind the layer l5, or may be omitted, if desired. Alternately, the layer l5 may simply comprise a suitable resilient cement applied to any desired or suitable thickness, and I have found that the layers l1 and 33 may be connected together with a resilient layer l5 therebetween merely by coating the surface of each with latex, clamping the parts together and heating to vulcanize the latex.

It will be understood from the foregoing that my invention broadly comprises the provision of a resilient blanket behind a printing element of the character mentioned and the invention is not necessarily restricted to the particular mode of applying such a resilient blanket. On the contrary, the invention consists broadly in the provision of any resilient blanket behind the printing element or electrotype during the printing operation in order that the printing element may yield in order that the resulting print may be uniform throughout its entire area.

It is thought that the invention and numerous of its attendant advantages will be fully understood from the foregoing description, and it is obvious that numerous changes may be made in the form, construction, and arrangement of the various parts, without departing from the spirit or scope of my invention and without sacrificing any of its attendant advantages, the forms herein described being simply selected embodiments for the purpose of illustrating the invention.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is as follows:

1. The method of mounting a relatively thin shell-l ke printing element, which consists in applying a resilient backing to the element and then hardening the backing opposite various localized areas of the elementv to a relatively greater degree than opposite the remaining areas.

2. The method of mounting a relatively thin shell-like printing element on a backing comprising a resilient layer, which consists in treating the layer in order to alter its resilience in accordance with the impression-making surface of the element and then mounting the element on the treated layer so that the corresponding portions of the element and layer are in registration.

3. The method of mounting a relatively thin shell-like printing element on a backing comprising a resilient layer of rubber, which comprises printing the y r with a. substance adapted to alter the resilience of said layer in accordance with the design on the printing surface of said element and then mounting the element on the printed layer with their corresponding portions in registration whereby the resilience of the layer corresponds throughout the area of the element with the character of the printing surface of said element.

4. The method of mounting a relatively thin shell-like printing element on a backing comprising a resilient layer of rubber, which comprises printing the rubber layer in uncured condition with an adhesive medium in accordance with the design on the printing surface of said element, thereafter dusting upon the printed surface of the layer a curing medium adapted to control the resilience of the layer and thereafter curing the layer and mounting the plate thereon in position such that the corresponding portions of the element and of the cured layer are in registration.

5. The method of mounting a relatively thin shell-like element, which consists in applying a resilient backing to the element and then differentially hardening the backing opposite various localized areas of the element to a relatively greater degree than opposite the remaining areas and applying a support of uniform resilience behind the differentially hardened backing.

6. As a new article of manufacture, a. unitary printing member comprising a thin printing element, a backing of resilient material secured to said printing element, and a substantially nonresilient filling layer between the backing and the printing element, said filling layer entering and filling the depressions on the back of the printing element.

'7. A unitary printing member as set forth in claim 6, wherein the filling layer comprises a metallic material applied to the back of the printing element and shaved to provide a flat surface to receive the resilient backing.

8. As a new article of manufacture, a printing member comprising a relatively thin element having a printing surface, certain areas of said surface requiring more printing pressure than other areas, a backing for said element comprising a yielding layer of resilient rubber, and a layer of relatively less resilient rubber behind the yielding layer.

9. As a new article of manufacture, a. printing member comprising a relatively thin. shell-like metallic element having a printing surface on one side, certain areas of said surface requiring more printing pressure to print evenly than other areas, and a resilient backing secured on the other side of the element, said backing providing yielding support of less resiliency behind the areas of the printing surface requiring increased printing pressure.

10. As a new article of manufacture, a. printing member comprising a relatively thin, shell-like metallic element provided with a printing surface on one side, certain areas of said surface requiring more printing pressure to print evenly than other areas of said surface, and a. backing secured to the other side of the element, said backing being adapted to provide relatively firm support behind the areas of the printing surface requiring increased printing pressure andrelatively more yielding support behind the areas of said surface requiring less printing pressure.

11. As a newarticle of manufacture, a printing member comprising a relatively thin shell-like element having a metallic printing surface on one side, certain areas on said surface requiring more printing pressure to print evenly than other areas on said surface, and a backing comprising a layer of rubber vulcanized differentially in different localities, whereby certain localized areas underment but thicker'than said element, adapted to force said flexible printing surface, under printing pressure into intimate and even contact with a surface to be printed upon, not co-planar with said printing surface, by locally bending said element to conform to said surface to be printed upon, and a film of adhesive material securing said backing to said metallic element.

PHILIP A. FRAZIER.

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