US1331140A - Method of forming curved printing-plates - Google Patents

Description

F. H. BEROLD.

METHOD OF FORMING CURVED PRINTING PLATES.

APPLICATION FILED MAR. 31, 191;.

1,33 1, 140. Patented Feb. 17, 1920.

5 SHEETS'SHEET 1.

F. hR BEROLD.

METHOD OF FORMING CURVED PRINTING PLATES.

APPLICATION FILED MAR. 3|. 19H.

Patented Feb. 17,1920.

5SHEETS-SHEET 2 F. H. BEROLD.

METHOD OF FORMING CURVED PRINTING PLATES.

APPLICATION FILED MAR. 3|. 1917.

Patented Feb. 17,1920.

5 SHEETSSHEET 3 I 37 jl w'exzfor:

i 3M, gm

F. H BEROLD.

METHOD OF FORMING CURVED PRINTING PLATES. APPLICATION FILED MAR. 31. 1911.

1 ,33 1 1 40, Patented Feb. 17, 1920.

5 sHEETs-sHEEr 4.

F. H. BEROLD.

METHOD OF FORMING CURVED PRINTING PLATES.

APPLICATION HLED MAR. 31,19!!- 1,33 1,140, Patented Feb. 17,1920.

5 SHEETSSHEET 5. '29 21$ fiwzni ozn' W 5% @M 6 My 9% ML UNITED srArEs agrnnrr orrron.

FREDERICK H. BEROLD, OF WYOMING, OHIO.

METHOD OF FORMING CURVED PRINTING-PLATES.

To all whom it may concern Be it known that I, FREDERICK H. BEROLD, a citizen of the United States residing at Wyoming, in the county of Ifamilton and State of Ohio, have invented certain new and useful Improvements in Methods of Forming Curved Printing-Plates, of which the followin is a specification.

My invention relates to the art of forming curved printing plates, and is useful where it is desired to maintain the relations of the printing lines of the printing surface or to avoid distortion of the printing lines during the bending.

It is especially useful for curving printing plates employed in multi-color printing, in which a plurality of printing plates are employed for printing different colors, the impressions of which are intended to register with each other.

The methods heretofore usually employed in curving printing plates have, in practice, caused a stretching of the printing surface, so that the printing surface of the curved plate has been of a diflerent size from its size when in the flat, it being understood that the printing plates are first formed fiat. When employing the usual methods of curving printing plates heretofore in general use, the printing lines of the printing surface were disarranged during the curving, with the result that the curved printing surface laid out in lane differed from the said surface when in the flat, the impressions of the curved printing surface having the spacings between its lines enlarged in the direction of the bending when compared with what they were when in the fiat.

It is the object of the invention to avoid or minimize these objections.

The invention consists in forming the printing plate with a plurality of layers comprising a printing-layer, a backinglayer, and an interposed binder-layer; in subjecting said layers to heat whereby said binder-layer is melted; in curving said layers while superposed whereby shifting movement between the proximate faces 'of the printing-layer and backing-layer takes place along the line of curvature; and, further, in subjecting the curved layers to pressure about a mold.

Specification of Letters Patent.

Application filed March 31, 1917. Serial No. 158,882. i

Patented Feb..1'7', 1920.

The invention consists further in subjectingsaid layers to heat, whereby to render said backing-layer spongy or readily flowable under pressure with relation to the printing shell and melting said binderlayer, curving said layers about a form or mold, whereby shifting between the proximatefaces of said backing-layer and said printing-layer takes place for maintaining the dimensions of the printing surface of sald printing-layer, and sub ecting said curved layers to pressure about said mold.

The invention consists further in providlng a printlng-layer, a backing-layer, and an interposed binder-layer; subjecting said layers to heat whereby said backing-layer is rendered readily bendable and said binder-layer is rendered fluid, and curving said layers about a form or mold from its middle portion progressively toward both ends of said layers, whereby shifting between the proximate faces of said printinglayer and backing layer at both sides of said middle portion toward said end portions takes place, and said backing-layer and printing-layer are rearranged as concentric layers formed as sectors of cylinders of different radii.

The invention will be further readily understood from the following description and claims, and from the drawings, in which latter:

Figure 1 represents a side elevation, partly broken away, of an exemplified machine employed in carrying out the invention, and showing a means for heating the layers.

Fig. 2 is a plan view of the same.

Fig. 3 is a cross-section of the heating means taken on the line 33 of Fig. 1.

Fig. 4 is a diagrammatic representation of the printing layers and bending means prior to the curving of the layers.

Fig. 5 is a similar view showing the layers partly curved.

Fig. 6 represents a side elevation of the curving machine, partly broken away, and showing the curving devices in raised position;

Fig. 7 is a similar view of the same, partly broken away, showing the curving operation completed, and the plate being subjected to pressure.

Fig. 8 is a cross-section of the same, taken in the plane of the line 88 of Fig. 2.

Fig. 9 is an end view of the curving machine.

Fig. 10 is a plan view'of layers about to be bent, partly broken away.

Fig. 11 is a longitudinal section of the printing-layer, backing-layer and intermediate binder-layer in superposed relation, taken on the line 11l1 of Fig. 10.

Fig. 12 is a cross-section of the same taken on the line 12 -12 of Fig. 10.

Fig. 13 is a central longitudinal section of the'curved plate as the same is received off of the curving apparatus; and,

Fig. 14; is a similar viewof a curved plate when trimmed, ready for being secured to a plate-cylinder of a printing press.

In performing the improved method, the printing-layer and backing-layer are preferably formed flat. An exemplified printing layer is shown at 15, a backing-layer at 16, and an intermediate binder-layer at 17. The printinglayer has a printing surface 18, the printing lines of which are exemplified at 19. Its margins are provided with bearers 25, 26, separated from the printing surface by grooves 27, 28, the bearers 25 being exemplified as at the ends of the printing plate, representing its top and bottom when secured to the plate-cylinder in a printing press, the bearers 26 being exemplified' as the side bearers. The bearers protect the printing surface during formation of the plate.

The printing surface is preferably on a printing-shell 29, composed of a material having a higher fusing point than the fusing point of the material of which the backing-layer is composed, and the binderlayer is preferably of a. material or composition having a lower fusing point than the fusing point of both the printing-shell and the backing-layer.

In performing the method, the layers are subjected to heat for rendering the backing material readily fiowable under pressure with relation to the material of the printing-shell, which will simultaneously render said binder-layer fluid. The condition of the backing-layer, due to heating of the same .for rendering the same readily bendable in the performance of the method, may be instanced as a spongy condition due to heat.

The curving of the layers about a form will cause a relative shifting movement between the proximate faces of the backinglayer and the printing-layer, and the binderlayer will upon cooling cause a uniting of said proximate faces for forming the layers intoan integral curved plate.

As an exemplification, but not as a limitation, it may be instanced that the backinglayer is a mixture of lead, tin and antimony. in the proportion of ninety pounds of lead to five pounds each .of tin and antimony, the fusing point of the mixture being approximately 600 degrees Fahrenheit.

The printing-shell is preferably. electrodeposited metal, for instance copper, deposited on the matrix in electro-plating, the fusing point of the copper being instanced as 1196 degrees Fahrenheit. It is within the scope and purpose of the invention that the printing surface may be formed by other means, either on a printing-shell or otherwise.

When a printing-shell is employed, the cavities 30 in the rear face of the printingshell may be filled with a material, for instance, similar to the material of the backing-layer, so that the rear face of the printing-layer shall be a flat face, the printinglayer being preferably as thin as the deeper indentations of the printing-layer will permit. 3

The binder-layer may be instanced as a layer of usual commercial tin foil, which has a fusing point less than the fusing point of either theprinting-layer or the backinglayer.

As an exemplification, but not as a limitation, it may be instanced that the binderlayer is a fusible alloy composed of lead, tin and bismuth, in the proportion of one pound of lead to three-quarters of a pound of tin and one and one-half pounds of bismuth, the alloy melting at approximately 212 degrees Fahrenheit.

The backing material, may if desired, be of gutta percha, or other material which is normally a solid, and the material filling the cavities in the rear face of the printinglayer may be of corresponding material, and the binder-layer may be of a suitable material or composition having properties whereby it Will melt prior to melting of said backing-layer and filling of said rear face of said printing-layer, and acting to bind said backing-layer and the printing-layer when cooled.

The heat applied is preferably of such temperature and its application is preferably of such duration as to cause the backing-layer of Whatever material composed, to become spongy or readily flowable under pressure with relation to the printing-shell. and to cause the binder-layer of material of a lower fusing point to be fused or melted when the material of the backing-layer shall have arrived at the aforesaid condition.

In the further description of the inven tion, it will be assumed that the printingshell is of electrodeposited copper, the backing-layer of the metal mixture of lead, tin and antimony hereinbefore mentioned, the filling material for the backing-layer being of similar composition, and the binder-layer being composedof said fusible alloy.

The proximate faces of the printing-layer and backing-layer, when these faces are coniposed of metal, are preferably provided with an acid coating consisting of muriatic acid, in order to aid the fusion of the binder-layer with'the backing-layer and the printingla er. i

While theapparatus is exemplified as employed in the performance of the method, the method may be performed by other apparatus, or with or without the employment of apparatus, as may be desired or found feasible.

Referring now to the exempllfied devlce employed in performing the improved method, means are exemplified for heating the layers of the printing plate, instanced as a heating table 33 which lsarranged to be heated, as by flames from gas-burners 34 formed, for instance, of perforated plpes under the table and fed from a suitable source of supply controlled by valves 35,

discharging into gas and air mixers 36, for' regulating the temperature applied to the table.

The layers of the printing-plate are preferably placed above the table in' up-sidedown relation upon a flexible band 37, which may be a sheet of cold rolled steel. If desired a cushioning layer 38, composed for instance of a sheet of paper, may be interposed between the printing surface of the printing layer and the flexible band.

The printing-plate layers are preferably held toward the table for pressing the various portions of the layers toward the table and thereby aiding in conveying uniform heat from the table to the printing plate layers.

This pressure may be accomplished by means of' a block 39 provided with blunt .presser-feet 40 of small cross-section adapted to bear upon the rear face of the backinglayer, the block being weighted by suitable weights ll for exerting proper pressures dependent on the size of the plate and to the resistance to a fiat disposition of the parts. Spaces 42 between the presser-feet permit observation of the condition of the layers.

The printing plate layers are subjected to the action of the heating agency until their condition is preferably such as hereinbefore. mentioned for bending the same. For instance, the point of liquefaction or fusion of the intermediate binder-layer is watched and as soon as this layer breaks down or melts and the backing layer becomes spongy, the layers are subjected to the curving operation while in such condition.

The curving of the .layers is exemplified as accomplished by a machine comprising a mold 45, rollers 46, 47, arranged to contact trough 48 in which the flexible band and. printin plate layers and the mold are received or exerting pressure upon the curved printing plate. The outer or forming face of the moldand the inner or forming face of the trough are sectors of concentric cylinders of different diameters.

The frame of the machine is exemplified at 51. The mold is formed on a slide 52 which has reciprocation by guides 50 in guideways 53 in the frame. The trough 48 is in a block 54 located in the frame.

Each of the rollers 46 is provided with gudgeons 56 journaled in bearings 57 of a yoke 58, comprising arms 59 connected by a cross-girt 60 and pivoted by bearings 61 about a rod 62. Springs 63 connect with the outer ends of the arms b articulations 64 and with eye-bolts 6,5 axia y movable in holes in lugs 66 extending from the main frame, adjusting nuts 67 adjusting the tension of thespring.

The yokes 58 form levers for pressing the plate-layers toward the mold. Movement of the rollers toward the mold is limited by adjusting bolts 68 adjustable in lugs 69 on the frame of the machine, the arms 59 contactin said bolts..

Eac of the rollers 47 has gudgeons 76 thereon ournaled' in bearings 77 on yokes 78, comprising arms 79 on which said bearings are located, and cross-girts 80 connecting said arms. The yokes-78 have bearings 81 on the rods,62. Sprin s 83 are articulated at 84 with the arms 9 at one of their ends, and at their other ends connect with eye-bolts 85 axially movable in holes in lugs 66 extending from the machine, adjusting nuts 87 adjusting the tension of the springs. Movement of the rollers 47 toward the mold in lugs 69 extending from the arms 7 9 contacting said bolts.

The rollers are so adjusted as to normally be in coincident horizontal planes a sufficient distance under the mold for permitting the flexible band with the printing plate layers thereon to be received by the rollers between the rollers and the mold, and acting as a table therefor.

Suitable means are provided for causing approach between the mold and the rollers, whereby the printing plate layers are curved about the mold by the action of the rollers while in the heated condition hereinbefore stated.

In the present exemplification, screw-rods 91 are arranged to turn in threaded bearings 92 in the cross-girt 93 of the frame of the machine. The screw-rods have sprocket wheels 94 fixed thereon, a sprocket-chain 95 being received about the sprocket-wheels.

An operating wheel 96 is fixed to one of the screw-rods. The screw-rods are journaled in bearings 97 to the mold slide, so arranged that frame, the

the slide will move up and down with the screw-rods, shown accomplished by forming the screw-rods with annular grooves 98 arranged to receive tongues 99 fixed to the slide, as by threading the bearing 97.

In performing the method, the printin plate layers are laid in correctly superposed relation, with their edges coincident, preferably in the middle of the flexible band with the flexible band in the middle of the heating table. The printing surface is placed face down toward the flexible band, with the cushioning layer 88 interposed between the printing surface and the flexible band, for protecting the printing surface,-if desired. The binder-layer is on the printing-layer and the backing-layer on the bindenlayer. The layers are Sllb]80t8(l to the heat of the Y heating table in this relation.

When the printing plate layers have been subjected to the proper temperature for the proper length of 'time, as hereinbefore set forth, the flexible band and the layers are quickly transferred to position between the bending rollers and the mold, preferably in such relation that the middle of the layers of the printing plate are coincident with the apex portioli or bottom in the arc of the sector of the cylinder of the mold nearest the printing plate layers and with the printing lines on the printing layer parallel with or perpendicular to the axis of the cylinder of which the forming portion of the mold is a sector. This positioning of the layers is for the purpose of so forming the curved plate that the printing lines will be parallel with or perpendicular to the axis of rotation of the plate cylinder of the printing press on which said curved plate may be secured.

When the slide is depressed, the rollers will act to bend or wrap the flexible band and the printing plate layers thereon about the mold, the springs exerting sutlicient pressure upon the rollers to cause the rollers to press the layers of the printing plate between the fiexible' band and the outer surface of the mold, causing the upper face of the backing-layer to lie close to the forming surface of the mold, this pressure continuing as a rolling pressure from the middle,

portion toward the outer end portions of the printing plate layers, as exemplified by a comparison of Figs. 4, 5 and 8. The move ment of the slide continues until the flexible band is seated in the trough and pressure of the slide upon the printing plate layers and the wall of the trough is exerted.

The bending or wrapping of the printing plate layers about the mold will cause shifting movement between the printing-layer and backing-layer, which progresses and increases from the middle portion toward the outer portions of said layer for rearranging the proximate faces of said layers with relation to each other. This causes the outer edges of the backing-layer to extend outwardly beyond the outer edges of the printing layer, as shown at 100, if said layers have been coincident when said layers were flat, as shown. The said layers are rearranged on the lines of concentric cylinders having coincident axes and radii of different lengths.

The binder-layer, being subjected to cooling action in the formation of the printingplate or while subjected to pressure, will cause the same to resolidify and unite the proximate faces of the printinglayer and backing-layer. This setting or solidifying of the binder-layer may, if desired, be accelerated by providing the slide 52-with a cooling medium, as 'by forming said slide with a cavity 101 in which a body 102 of cooling liquid, for instance water, is contained. This cooling liquid may be supplied through an inlet port 103 and discharged through an outlet port 104, a valve 105 regulating the supply of the water and the consequent temperature of the water in the body 101. Flexible hose 106, 107, may connect with the respective inlet and outlet ports.

The layers of the printing-plate, the cushioning layer and the flexible band are pref-' erably received in a peripheral recess 108 in the mold while being curved and during the pressing operation, the ends of the flexible band being received in shallower recesses 109, which are continuations of the recess 108. The peripheries of the side-walls 110 of these recesses act as bearers for the rollers 46, 47, for limiting approach of the rollers toward the mold, the said peripheries being further arranged to seat in the bottom of the trough, thus preventing excess pressure upon the layers of the printing-plate while being acted on by the rollers or pressed in the trough.

The curvature of the forming portion of the mold is preferably a sector of a cylinder having a radius approximately the radius of the plate-cylinder to which the printingplate is arranged to be secured, preferably making allowance for a slight finishing cut to be taken off of the rear face of the backing of the curved printing-plate.

lVhen the plate has been curved, its bearers 25 and 26 are preferably removed in suitable manner, and its edges provided with securing faces 111 in suitable manner, by means of which securing faces the printingplate is arranged to be secured to the platecylinder by ordinary means.

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

1. The method of forming curved printing plates which consists in superposing a metal printing layer and a backing layer,

simultaneously curving said layers to different'eoncentric curvatures having coincident axes in manner whereby shifting between their proximate surfaces takes place. and fixedlv connecting said layers.

2. lhe method of forming curved printing plates which consists in superposing a metal printing-layer. a metal backinglayer, and an interposed meta'l binder-layer, simultaneously curving said layers about a mold in manner whereby shifting between the proximate surfaces of said printinglayer and backing-layer takes place, and causing pressure upon said curved layers to conform them to said mold. whereby to cause said binder-layer to connect said proximate surfaces.

3. The method of forming av printing plate which consists in forming a printinglayer, a backing-layer. and an intermediate binder-layer, superposing said layers with said binder-layer between said printinglayer and backing-layer, rendering said backing-layer bendable by heat and fusing said intermediate binder-layer, and combinedly curving said layers, whereby shifting between the proximate surfaces of said printing-layer and backing-layer takes place.

l. The method of forming a curved printing plate which consists in superposing a printing-layer, a backing-layer, and an intermediate binder-layer, subjecting said layers to heat and rendering said backing-layer spongy and fusing said intermediate binder layer, and applying bending force to said layers for simultaneously curving said print ing-layer and said backing-layer, whereby shifting between the proximate surfaces of said lastnamed layers takes place, and said binder-layer binds said printing-layer and backing-layer in shifted positions.

The method of forming a curved printing plate which consists in superposing a printing-layer, a backing-layer, and an intermediate binder-layer, subjectingsaid layers to heat and rendering said backing-layer spongy and fusing said intermediate binderlayer, applying curving force to said layers from the middle portions thereof outwardly toward their ends, and applying pressure to said layers, whereby shifting between the proximate surfaces of said printing-layer and backing-layer takes place, and said binder-layer binds said printing-layer and backing-layer in shifted positions.

6. The method of forming a curved printing plate which consists in superposing a. printing-layer, a backing-layer, and an 1ntermediate binder-layer, subjecting said layers to heat and rendering said backing-layer spongy and fusing said intermediate binderlayer, applying curving force to said layers from the middle portions thereof outwardly toward their ends and applying pressure to said layers, whereby shifting between the proximate surfaces of said printing-layer and backing-layer takes place and said binder-layer binds said printing-layer and backing-layer in shifted positions, and trimming the edges of said connected layers.

7. The method of forming a curved print ing plate which consists in superposing a printing-layer, a backing-layer and an intermediate binderlaye'r, subjecting said layers to heat for rendering said backing-layer spongy and fusing said intermediate binderla yer, applying curving force to said layers for simultaneously bending said printinglayer and said backing-layer, whereby shifting between the proximate surfaces of said last-named layers takes place, apply ing pressure to said layers, and causing said layers to cool, whereby said binder-layer binds said printing-layer and backing-layer in shifted positions.

8. The method of forming a curved printing plate which consists in superposmg a printing-layer, a backing-layer and an inter? mediate binder-layer, subjecting said layers to heat and rendering said backing-layer spongy and fusing said intermediate binderlayer, curving said layers about a form by bending pressures applied from the middle portions toward the end portions of said layers, applying pressure to said superposed layers about said form, and cooling said layers, whereby said binder-layer binds said printing-layer and backing-layer in shifted positions.

9. The method of forming a curved printing plate which consists in superposing a printing-layer, a backingdayer and an intermediate binder-layer, subjecting said layers to heat applied from the printing-layer side of said layers, curving said layers by pres- 1 sures applied from the middle portions toward the end portions of said layers, whereby shifting between the proximate surfaces of said printing-layer and backinglayer takes place, and cooling said layers from the side of said backing-layer.

10. The method of forming a curved printing plate which consists in superposing a printing-layer, a backing-layer and an intermediate binder-layer, subjecting said layers to heat applied from the printing-layer side of said layers, curving said layers in manner whereby shifting between the proximate surfaces of said printing-layer and backinglayer takes place, cooling said layers from the side of said backing-layer, and trimming the inner surface of said backing-layer.

11. The method of forming a curved printing plate which consists in superposing a printing-layer, a backinglayer and an intermediate binder-layer, subjecting said layers to heat for rendering said backing-layer spongy and fusing said intermediate binderlayer, applying bending force to said layers from their middle portions toward their end portions for simultaneously curving said printing-layer and said backing-layer with said binder-layer therebetween where by shifting between the proximate surfaces of said printing-layer and backing-layer takes place, and cooling said layers, whereby said binder-layer sets and binds said printing-layer and backing-layer in shlfted positions.

12. The method of forming a curved printing plate which consists in superposing a printing-layer, a backing-layer and an 1ntermediate binder-layer, subjecting said layers to heat for rendering said backing-la er spongy and fusing said intermediate bin erlayer, applying bending force to said layers from their middle portions toward their end portions for simultaneously curving said printing-layer and said backing-layer with said binder-layer therebetween whereby shifting between the proximate surfaces of said printing-layer and backing-layer takes place, applying pressure to said layers, and cooling said layers, whereby said binderlayer sets and binds said printing-layer and backing-layer in shifted positions.

13. The method of forming curved printing plates comprising a printing-layer and a backing-layer, which consists in heating said layers, simultaneously curving said layers to different concentric curvatures having coincident axes by pressures applied from the middle portions toward the'end portions of said layers during shifting movement between the proximate faces of said layers, and fixedly connecting said layers.

14. The method of forming curved printing plates comprising a printing-layer and a backing-layer, which consists in heating said layers, curving said layers simultaneously between a flexible band and a form by pressures applied from the middle portions toward the end portions of said layers during shifting movement between the proximate faces of said layers, and fixedly connecting said layers.

15. The method of forming curved printing plates comprising a printing-layer, a backing-layer and an interposed binderlayer, which consists in heating said layers to a point near the fusing point of said backing-layer and melting said binder-layer, combinedly bending said layers about a mold while so heated so as to cause endwise shifting movement between the proximate faces of said printing-layer and backinglayer, and permitting said layers to cool for setting said binder-layer and fixing said printing-layer and backing-layer together.

16. The method of forming curved printing plates comprising a printing-layer, a backing-layer and an interposed binderlayer, which consists in heating said layers to a point near the fusing point of said backing-layer and melting said binder-layer, combinedly bending said layers about a mold while so heated by applying progressively acting pressure said mold from the middle portions toward both end-portions of said layers in manner to cause shifting movement between the proximate faces of said printing-layer and backing-layer, and permitting said layers to cool for setting said binder-layer and fixing said printing-layer and backing-layer together.

17. The method of forming curved printing plates comprising a printing-layer, a backing-layer and an interposed binderlayer, which consists in heating said layers to a point near the fusing point of said backing-layer and melting said binderlayer, combinedly bending said layers about a mold while so heated by applying progressively acting pressure to said layers about said mold from the middle portions toward both end portions of said layers in manner to cause shifting movement between the proximate faces of said printing-layer and backing-layer, subjecting said bent layers to pressure, and permitting said layers to cool for setting said binderlayer and fixing said printing-layer and backing-layer together.

18. The method of forming curved printing plates comprising a printing-layer, a backing-layer, and an intermediate binderlayer, which consists in heating said layers to render said backing-layer readily flowable under pressure and melting said binderlayer, and then combinedly bending said layers about a curved form by pressure applied progressively from the middle portions toward the end portions of said layers.

19. The method of forming curved printing plates comprising a printing-layer, a

to said layers about backing-layer, and an intermediate binden' layer, which consists in heating said layers to render said backing-layer readily flowable under pressure and melting said binderlayer, and then combinedly bending said layers about a curved form by pressure transferred to said layers through a flexible band, said pressure applied progres sively from the middle portions toward the end portions of said layers.

20. The method of forming curved printing plates comprising a printing-layer, a backing-layer, and an intermediate binderlayer, which consists in heating said layers to render said backing-layer readily flowable under pressure and melting said binderlayer, then combinedly bending said layers about a curved form by pressure applied progressively from the middle portions toward the end portions of said layers, and cooling said layers for setting said intermediate binder-layer and fixing said printing-layer and backing-layer together.

21. The method of forming curved printing plates comprising a printing-layer, a backing-layer, and an intermediate binderlayer, which consists in heating said layers to render said backing-layer readily flowable under pressure, and meltingsaid binderlayer, then combinedly bending said layers about a curved form by pressure applied progressively from the middle portions toward the end portions of said layers, and subjecting said layers to pressure while cooling said layers for setting said intermediate binder-layer and fixing said printing-layer and backing-layer together.

The method of forming curved printing plates comprising a printing-layer, a backing-layer and an intermediate binderlayer, which consists in heating said layers to render said backing-layer readily flowable under pressure with and melting said binder-layer, combinedly bending said layers about a curved mold by rolling pressure applied from the middle portions toward the end portions of said layers, and subjecting said curved layers to pressure.

The method of forming curved printing plates comprising a printing-layer having a printing shell, a backing-layer and a binder-layer, which consists in subjecting said layers to heat while under pressure for rendering said backing-layer readily flowable under pressure with relation to said printing shell and melting said binder-layer, and bending said heated layers into curved form about a curved mold by pressure applied progressively from the middle toward the end portions of said layers.

24:. The method of forming curved printing plates comprising a printing-layer having a printing shell, a backing-layer and a binder-layer, which-consists in subjecting said layers to heat while under pressure for rendering said backing-layer readily fiowable under pressure with relation to said printing shell and melting said binder-layer, and bending said heated layers into curved form about a curved mold by pressure applied progressivelv from the middle toward the end portions of said layers, and subjecting said curved layers to pressure.

25. The method of forming curved printing plates comprising a printing-layer having a printing shell, a backing-layer and a binder-layer, which consists in subjecting said layers to heat While under pressure for rendering said backing-layer readily flowable under pressure with relation to said printing shell and melting said binder-layer, bending said heated layers into curved form about a curved mold by pressure applied progressively from the middle toward the end portions of said layers, subjecting said curved layers to pressure, and cooling said curved layers.

26. The method of forming curvedprinting plates comprising a printing-layer, a backing-layer and an intermediate binderlayer, heating said layers for rendering said backing-layer readily bendable under pressure and melting said binder-layer, and wrapping said layers about a curved form by pressures applied through a flexible band to said layers from their middle portions progressively toward their end portions.

27. The method of forming curved printing plates comprising a printing-layer, a backing-layer and an intermediate binders layer, heating said layers for rendering said backing-layer readily bendable under pres sure and melting said binder-layer, wrapping said layers about a curved form by pressures applied through a flexible band to said layers from their middle portions progressively toward their end portions, and subjecting said curved layers to pressure.

28. The method of forming curved printing plates comprising a printing-layer, a backing-layer and an intermediate binderlayer, heating said lavers for rendering said backing-layer readily bendable under pressure and melting said binder-layer, Wrapping said layers about a curved form by pressures applied through a flexible band to said layers from their middle portions progressively toward their end portions, subjecting said curved layers to pressure, and cooling said curved layers while being subjected to said last-named pressure for setting said binder-layer.

In testimony whereof, I have hereunto signed my name in the presence of two subscribing witnesses.

FREDERICK H. BEROLD.

Witnesses:

THERESA M. SILBER, CHARLES E. WEBER.

Images