US1643046A - Printing form and method of producing same - Google Patents

Description

Se'pt" 1927' v E. BALLARD 1'643'046 PRINTING FORM AND METHOD OF PRODUCING SAME Original Filed March 19, 1926 Zlnvc 11 Too Patented Sept. 20, 1927.

UNITED STATES manner :1. BALLARD, or annexe,- camroanm. H

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} v 1,643,046 PATENT OFFICE.

Application filed March 19, 1826, Serial No, 96,020. Renewed December 8, 1926.

This invention relates to improvements in printing forms or surfaces for use in photogravure, rotary photogravure and like processes and to a novel method of producing such forms or surfaces.

, Some of the printing forms heretofore proposed for use in the above mentioned processes have embodied a base on which there was deposited an exterior layer of metal adapted to receive the image to be repro ducedin some instances, and, after the required reproductions had been made, such exterior layer would be removed by subjecting the form to anacid which would remove said layer. etching on the outer surface is removed by grinding, a process which is slow and costly and also reduces the cross section of the form.

, Removal of the outer etched surface by acid is costly, wasteful and uneven in re- *sult's. Removal by grinding is' slow and costly. For these reasons, the primary object contemplated by the present invention conslsts in providinga novel printing form for photogravure or rotary photogravure processes, as well as a novel method of preparing such a form, the salient characteristic of the form being that the exterior layer, on which is received the engraved image. to bejprinted, may be speedily removed from the permanent base without the use of acids or by slow and costly grinding. The improved process herein disclosed for the production of printing-forms provides a means of depositing by-electrolysls upon a metallic base, preferably cylindrical in form, a layer of metal preferably copper, in such a manner that the layer or coating, though surrounding'the base and remaining in close contact therewith by? reason of its own cylindrical and all-ernbracingform, can at any time bestrilpped from the base by peeling or tearing t cumferential ends of the base. The process also provides, in order to further guard against theremoval of the outer layer of metal until such removal is'desired, a seal or look for-a narrow marginalong the two circumferential ends of the cylinder, said seal consisting of an actual mechanical union between the outer layer and'the base, eflected by electrolytic action.

Referring to the figures of the drawing: Fig. 1 is a perspective view of aprinting roll showing the use of my invention.

In other instances, the previous erefrom, beginning at the. cirby in the solution and; known as the. anode, the revolving cylinder being the'cathode and.v

Fig. is an enlarged fragmentary sectional view thereof.

assure While the printing form may assume any desired shape, in so far as the (practice of 10 is a thin layer or coating of material 11 of relatively low .fusibility, preferably an alloy oftin, lead, cadmium and bismuth or other alloy of low fusibility, which is applied to base 10 by raising the temperature of base 10 to a higher degree than the melting point of thealloy, and .then applying the same, using suitable fluxes,and wiping the alloy over-the entire useful surface of base 10, polishing off to a uniform mirror finish. Other suitable means common issoldering practices can be utilized to apply and uniformly distribute the coating of alloy.

On the very thin layer 11 there is a plied an exterior coating 12 of some metal a apted to receive the images to be. printed. In actual practice it is preferred to form said layer 12 of copper, the base 10 of copper or brass, an the intermediate layer of an alloy of lead, in bismuth and cadmium, or other 'alloy, in such proportions as will give an alloy melting point of about 202 degrees Fahrenheit.-

With the base -10 coated with this alloy of lead, tin, cadmium and bismuth, or other alloy, but with narrow margins at each end, 13 and 14, exposed and-presenting a portio'nof the base not covered with the alloy, the form is immersed in a plating solution composed of coppersulphate, water and sulphuric acid in approximate proportions of two pounds of copper sulphate and one half pound of sulphuric acid to one gallon of water, and kept in rapid uniform rotation, while'subje'cted to a current ofelectricity passing from a sheet of copper placed near.-

being" electrically connected with'the source of current'supply, the whole being the arrangement commonly used in the electrode osition of copper.

nder such treatment, with brisk uniform rotation of the cylinder, the {very thin layer or coating 11 on the cylinder takes on a able forprinting purposes such as before mentioned.

Although electro-deposited upon the coating 11, the layer 12 is not mechanically or otherwise attached thereto, it being a peculiar and requisite characteristic of the alloy surface, that the thin layer of eleotro-deposited copper 12, by reason of the electrochemical reactions with the alloy during the electroplating as formerly noted, does not adhere to the surface of the alloy 11. The alloy at all times provides a uniform conducting basic surface favoring the uniform distribution of a copper deposit from the moment the electrodeposition begins. While this isolation of the copper surface might be accomplished between itself and any base by the interposition of a coating of grease, graphite, lacquer, or similar composition, such isolating results in extremely uneven plating, so that the final electrodeposited surface is not in condition to, receive an etched image, without the customary and usual grinding and surfacing treatment.

The only mechanical connection established by the electrolytic action is at margins 13 and 14, where the copper conveyed from the anode has firmly attached itself to the uncovered copper or brass surfaces of these margins, acting as an airtight seal and'lock for the cylinder of copper that has been deposited upon the coating 11. Thus the layer 12, in intimate but not mechanical connection with layer 11, is further kept in close contact therewith by atmospheric pressure.

This lack of actual mechanical adhesion follows from the fact that coating 11, consisting of an alloy of low melting point, preferably lead, tin, bismuth and cadmium, or other metal, upon being placed in the electroplating solution as heretofore mentioned and described, is affected electrochemically by the plating solution preventing the copper, conveyed to coating 11 "by electrolytic action, from entering into mechanical or actual connection or a dhesion with the alloy, although establishing a certain degree of union that maintains layer 12 in close and intimate contact with coat 11. The electrically deposited coat 12,'being cylindrical in form and sealed at each'end by the actual mechanical and airtight contacts at 13 and 14 becomes for all practical purposes an integral part of the printing form, and after slight polishing and bufling is ready to receive the engraved image.

' After the form thus made has had the desired impression or image placed thereon andhas been used, if it is deslredto remove such impression and substitute another, the

seal at the ends 13 and 14 is broken by filing the circumferential edge or by using other abrasive means when it will be found that layer 12 superimposed upon coat 11 is not adhering thereto, and by starting with a knife edge or otherwise can be readily peeled off leaving coat 11 ready to receive another electrodeposited layer 12, if coat 11 is undamaged. Otherwise coat- 11 is restored to proper condition by flowing on new metal as in common soldering practices, or as heretofore described, after which the process may be repeated.

By being thus" able to easily and speedily remove the impression carrying layer 12, the present invention eliminates the grind- .ing down of the copper or other base and the surface of the base 10 is highly polished and if coat 11 is evenly applied thereupon, and likewise polished to a uniform mirror-like surface, it will follow that layer 12, preferably of copper, will go on smoothly, and only a comparatively thin layer will be required for a printing surface. Thus the electrical energy and time required in other processes for heavily coating the form with copper and in subsequent turning and grinding back to uniform shape and size is rendered unnecessary.

While I have herein specifically described and illustrated the preferred method of carrying out my invention, it will of course be understood that the same is capable of various modifications within the scope of the appended claims without departing from the s irit thereof. For example, while I preferab y employ the said metalic coating 11 in the manner herein described and illustrated, it will be obvious that the employment of means other than this specific coating for preventing adherence of the layer 12 is within the scope of my invention.

Non-adhesion between the major portion of the outer layer and cylinder may be effected in numerous ways. Grease, oil, graphite or tarnishing and oxidizing reagents may be spread over the surface of and like processes, consisting of providing on a permanent base a layer of material wit which the metal used thereon for printing llt) forms or surfaces for use in photogravure will not permanently unite, and providing a thin coating-of the required metal onthe said layer baseby electrodepositing the said metal thereon, the coating being adapted to be readily stripped from the base after use.

2. The method of producing printing forms or surfaces for use in photogravure and like processes, consisting of "providing on the greater portion of a permanent base a layer of material with which the metal used thereon for printing will not permanently unite, and providing a thincoating of the required metal on the said layer base by electrodepositing the said metal thereon,

the said metal and base uniting to form a seal at the portions not covered by the said.

layer, and the coating being adapted tobe readily stripped from the base after use by. breaking this seal.

3. The method of producing cylindrical printing forms or surfaces for use in photogravure and like processes, consisting of pro- .viding on the greater portion of the cylindrical surface between the marginal edges thereof a layer of material with which the metal used thereon for printing will not permanently unite, and providing a thin coating of required metal on the said layer base by .e'lectrodepositing action, the coating being freely removable from the cylinder ex-' 'ceptat the marginal portions where the metal unites with the base to form a seal.

4. The method ,of producing printing forms or surfaces for use in photogravure and like processes which consists in applying to a permanent base a layer of material of. low fusibility which may be distributed evenly over said permanent base and polished to a'mirror smoothness conforming to the surface of the base. itself. and coating said layer with a metallic coating on which the image to be printed may bereceived.

' .5, The method of producing printing surfaces for use in photogravure and like processes which consists in applying to a permanent base a layer of metal of low melting point, and applying to said layer by electrodeposition a layer of copper upon which the image to be printed may be received.

6 The method of producing successive printing-surfaces for use in photogravure and like processes which consists in. applying to a permanent base a layer of metal of low fusibility and electrodepositing a layer of copper thereon, said layer ofcopper adheringto the coating of low fusibility with-. out having av mechanical connection there with, whereby the copper layer may atany time be stripped therefrom.

7. A printing form for use in photogramanent base, a thin layer of metal of low' relative fusibility on said base, and an exterior layer electrodeposited thereon but not adhering to the inner layer of metalof low 'fusibility, but adhering and entering into mechanicaLunion with the base on its margin where there is no covering of metal of low fusibility, said layer on the exterior of said metal of low fusibility being removable .by' cutting or breaking those portionswhere adhesion exists between the exterior layer and the base and thereafter stripping away the remaining portions which have not adhered to the metal of low fusibility.

9. A printing form for use in photogra- I vure and like processes consisting of apermanent base, a thin layer of metal of low fusibility on said base, and an exterior layer of metal electrodeposited thereon, said exterior layer having a mechanical connection or union with said base and substantially free of the layer of metal of low fusibility .Whereby said exterior layer may be removed from the layer of metal .of low fusibility without affecting the latter. 0

10. A printing form for use in photogravure and like processes consisting of a prmanent base, a thin layer of metal of low fusibility on said base andan exterior layer. covering said base and said metal of low fusibility, there being a mechanical connection between said base and exterior layer only'for retaining said layer on the form.

11. The method of producing. printing surfaces for use in photogravure and like processes which consists in applying to a permanent base a coating of an alloy of tin,

lead, cadmium and bismuth, and applying to said coating by electrodeposition a layer of copper npon which an image to beprinted may be received.

. ERNEST s. BALLARD,

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