US2346230A - Etching printing rolls - Google Patents

Description

April 11, 1944. J. J..ORMOND ETCHING PRINTING ROLL 2 Sheets-Sheet 1 Filed Dec. 28, 1942 April 11, 1944.

J. J. ORMOND ETCHING PRINTING ROLL Filed Dec. '28, 1942 2 Sheets-Sheet 2 Patented Apr. 11, 1944 ETCHIN G PRINTING ROLLS John J. Ormond, Boston, Mass., assignor 01' twothirds to Joseph D. Ramsey, Boston, Mass.

Application December 28, 1942, Serial No. 470.411

6 Claims.

This invention relates to printing and more especially to engraving printing rolls of the type employed in textile color printing.

An object of the invention is to improve methods of etching printing rolls and more especially to devise a procedure for applying acid resist to rolls with a view to shortening the time ordinarily required for such operations, and to decreasing the number of etching operations resorted to. Another object of the invention is to provide a method of etching which simultaneously forms different types of ground lines by means of which two tones of color printing may be carried out on textiles and other materials. Another object is to provide a simple, cheap and eflicient method of etching.

The nature of the invention and its objects will be more fully understood from the following description of the drawings and discussion relating thereto.

In the accompanying drawings:

Fig. 1 is a view in side elevation illustrating a step in the method of the invention;

Fig. 2 is a cross sectional view taken on the line 22 of Fig. 1;

Fig. 3 is a plan view illustrating another step in the method;

Fig. 4 is another cross sectional view taken on the line 44 of Fig. 3;

Fig. 5 is a view in side elevation illustrating another step in the method;

Fig. 6 is a cross sectional view taken on the line 6-6 of Fig. 5; 7

Fig. 7 is a view in side elevation illustrating still another step in the method referred to;

Fig. 8 is a cross section taken on the line 88 of Fig. 7;

Figs. 9, 10 and 11 are views in side elevation illustrating still other steps in the method referred to; and

Fig. 12 is a view in side elevation illustrating a roll engraved in accordance with the method of the invention.

In making textile printing rolls for printing dye colors, it is now customary to obtain intaglio or etched printing surfaces by two etching operations. The first operation consists in etching an outline of any given design which may be desired. Such an outline is obtained by coating the roll with asphaltum and cutting through the asphaltum an outline of the design by means of a pantograph machine. Acid reagent, as iron perchloride, is allowed to etch into the copper roll through the outline, and thereafter the etched outline tus obtained is filled with enamel or other acid resist. V

The second necessary etching operation, in the conventional method of making a textile printing roll, consists in again coating the roll over its entire surface with a light asphaltum. When dry, diagonally disposed ground lines are cut into the asphaltum coating by means of a. knurling tool, or some other suitable apparatus. 1 Since these knurled ground lines extend throughout the surface of the roll, and both inside andoutside of the portions of the roll surface included. within the design outline, it becomes necessary to paint out with heavy asphaltum those areas of the roll surfaceoccurring outside of .the design out: line Where no engraving is desired to take place. The roll, selectively coveredv with. heavy asphaltum, is then etched a second time to provide angularly disposed ground lines insideof the design outline, and these ground ,lines receive and print dye colors, thereby to furnish suitable shading or strength of the colors on a textile material.

The present invention generally includes the step of simultaneously etching design outlines and two or more types of ground lines, thuseliminating several independent etching; steps and painting ou operations. The method consists in superimposing one upon another on a copper roll three diiferent acid-resist materials, eachvof which is soluble in a solvent not affecting the other two. Two of the acid-resistmaterialsare first applied in the form of diagonally disposed lines which extend in opposite directions from one another, and which are appliedone over the other. The third acid-resist occursin the form of a coating completely covering the first two applied sets of diagonal lines of resist materials. By the use of a pantograph at this point, a design outline is cut through the several acid resists,laying bare an outline portion of the copper roll surface. A second toneoutline within the first design outline is also cut through the resists to form an area in which a different ground is to be etched for variation in color tone. The area between the design outline and the shade outline is formed with ground lines, as for example crossed lines, which when inked will furnish a dark tone, while the area within the second tone outline is formed with ground lines, as for example a series of parallel lines, which when inked will furnish a light tone. p

Selective removal of the thirdacidr'esist from the area within the design outline and the second tone outline is first carried out to uncover crossed lines of the two first applied resists. The acid resist making up one of the sets of lines is then removed from within the second tone outline only, and the plate is then etched.

Referring more in detail to the drawings, Figure 1 illustrates the step of applying on the surface of a copper roll I a series of lines 2 diagonally disposed between the ends of the roll and spaced apart to leave uncovered portions of the roll surface. These lines consist of an acid-resist material preferably made up of a substance such as beeswax.

One suitable manner of applying the beeswax in the for'in of lines consists in first coating the roll I with beeswax heated to a temperature at which it is relatively liquid. The coating thus obtained is allowed to cool andthe linesare formed by scoring the coating to form the spaces 3, as illustrated in Fig. 1. Such scoring maybe carried out for example by means of a knurling tool or in some other desired way.

In accordance with a further step in the method of the invention, a second set of diagonal lines is applied over the first set of lines 2. This is accomplished in the manner diagrammatically illustrated by Figs. 3-6 inclusive. of the drawings.

Considering this more fully, numeral 4 illustrates a transfer member which may, for example, consists of a sheet of relatively hardsurfaced paper, such as onion skin paper, one side of which has been coated with gelatin. Upon the gelatin coated side of the paper 4. is printed Numeral 6 denotes the spaces occurring betweenthe lines 5.

The gelatin coated paper containing the ink lines 5 is then brought into. contact with the roll:

I in some suitable manner as by rolling the sheet thereagainst, thustransferring the ink lines. 5 over the ink-lines 2 in thelmanner illustratedin Figs. 5 and 6 of thedrawings. The-lines. 5 are applied in such a manner that they extenddiagonally with respect to the ends of the roll I and.

oppositely to the lines 2, thus resulting. in the surface of-the roll I presenting a series of crossed lines between which occur. the interrupted spaces.

3 of bare copper.

The acid-resist material making up the second set of diagonal lines- 5 is allowed to dry. The entire surface of the roll, as well as the two sets of diagonal lines Z-and- 5, is then covered witha coating 6 of another acid-resist material which may, for example, consist of a mixture of glycerin and mercurousnitrate (Figs. 7 and 8). The coating is dried and then subjected to the action of hydrogen chloride gas. means of treating the coating consists in suspending the roll in a chamber containing hydrogen gas. Exposure for a period'of several minutes is sufiicient for purposes of the invention.

The treatment of hydrogen chloride gas converts the mercurous nitrate to mercurous chloride, which occurs in the form of a white crystalline mass having the property of being substantially resistant to acid 'resists employed in etching copper rolls, as for example iron per- One suitable chloride. In addition, the mercurous chloride is soluble in reagents which do not affect the other resists noted.

The roll thus provided with three different acid resists on its surface is then formed with a design outline I, cut through each of the resists to lay bare an outline portion of the copper roll surface. This cutting operation may be carried out, for example, by a pantograph machine of the type conventionally employed in making textile printing rolls. Other means of forming the design outline may be resorted to if desired.

A second outline 8, which I prefer to designate as a tone outline, is then cut through the three acid resists at points within the first described design outline i. Fig. 9 diagrammatically illustrates the steps of forming two different outlines, one within the other. These outlines, for the sake of simplicity in describing and illustrating the invention, consist of a relatively simple cross design. However, it is intended that such a showing may be illustrative of various other types of designs, commonly employed in printing textile materials.

Selective removal of acid-resist materials is then carried out to prepare the roll for the final etching operation. Figs. 10 and 11 diagrammatically illustrate one suitable method of removing selective amounts of acid-resist material. By means of a pad or other suitable element, a solvent i'or mercurous chloride is lightly applied over those portions of the mercurous chloride coating 8 which occur within the design outline T, as illustrated in Fig. 10. One suitable solvent for mercurous chloride is ammonium hydroxide. Other bases may be resorted to.

Upon dissolving away a. selective amount of the mercurous chloride in the manner noted, there results an area on the surface of the roll defined by the design outline I, in which two sets of diagonally extending lines, opposed to one another, appear.

A further removal of acid-resist material making up one of these sets of diagonal lines is then carried out. This may be done for example by treating the portion of the roll surface included within the outline 8 with a solvent for one of the sets of lines, as for example theink lines 5; A suitable solvent for the ink lines; 5 is turpentine or benzine, and other organic liquids, and such solvents may be applied by means of a pad or brush lightly passed over the roll surface within the outline portion 8.

After carrying out removal .of selective amounts of two different acid resists in the manner described, there remain an area includedwithinthe outline 8 which presents only portions of the lines 2 ofbeeswax and spaces 3.occurring therebetween. When this part of the rollis immersed in an acid reagent, it will be seenthat etching may proceed along the areas defined by the spaces 2 to form one set of ground lines.

In that part of the roll-surface occurring between the outline8and the design outline i,

there appear diagonal lines 2, andthe diagonal etching to take place in the form of a grain" which will hold printing ink differently than the lines 3 which appear within the outline 8.

Thereafter the roll is immersed in the conventional manner in an etching reagent such as iron perchloride, and etching is allowed to proceed for a desired period. After completion of etching, the various resists are removed. Ammonium hydroxide dissolves away remaining portions of the mercurous nitrate. Turpentine or other organic solvent removes the lines and hot water takes away the lines 2 of beeswax.

As a result of these operations there is obtained an etched outline 9 and a second etched outline Ii] within the etched outline 9. Also between the etched outlines 9 and ill occurs a multiplicity of etched squares H, and inside of the etched outline iii occurs a series of etched lines [2.

These etched portions of the roll surface, when furnished with dye colors in the manner common to textile printing operations, will print such colors on a textile material.

It will be observed that the etched ground lines l2 constitute one type of grain which may be designed to hold a relatively larger amount of dye color than tiny etched squares ll, constituting a different type of grain occurring within the etched outline I0 and the etched outline 9. In this way, two tones or shades of a given dye color may be printed.

An outstanding feature of the invention is the step of simultaneously etching both outlines and two-tone ground lines. The improved method of applying resist material employing a series of different acid resists, each of which is soluble in a solvent not affecting the others, makes possible such a result.

Use of mercurous chloride in forming the coating 6 is intended to be illustrative of use of other chemical reagents, and their conversion to an acid-resistant condition; and the solvent ammonium hydroxide employed to dissolve the mercurous chloride, is intended to be illustrative of other solvents employed in this way.

The various operations described are of a relatively simple character, may b quickly carried out and do not require the skill and attention which are required for conventional pantograph operations, followed by painting out with heavy asphaltum. By forming the two sets of outlines in the manner described, the solvent materials may be rapidly brushed in or otherwise applied at desired points, thus saving considerable time as well as affording a higher degree of accuracy and sharpness of outline subject matter.

While I have shown a preferred embodiment of the invention, it should be understood that Various modifications may be resorted to, as for example in applying the method in connection with other types of etching operations or in other ways, while still continuing to adhere to the spirit of the invention as defined by the appended .claims.

I claim:

1. That improved method of engraving textile printing rolls which comprises applying an acidresist material, in the form of spaced-apart diagonal lines, on the surface of the roll, then applying a second acid-resist material in the form of diagonally extending lines which cross the lines of the said first resist material, each of said applied resist materials being insoluble in a sol vent of the other, coating the roll and crossed lines of the first two applied resist materials with a third resist material, said third resist material being soluble in a solvent which does not dissolve either of the two first applied resist materials, cutting a design through the several resist materials to lay bare a portion of the roll surface, removing portions of the last applied resist coating at selected points on the roll surface, re-.

moving portions of the last applied acid-resist coating and portions of lines of one of the resist materials at other points, and then etchingthe roll.

2. That improved method of engraving textile printing rolls which comprises applying on a copper roll a series of spaced-apart diagonal lines of acid-resist material, applying a second series of oppositely extending diagonal lines from the said first series of lines, coating a third resist material over both of the first and second series of acid-resist lines, cutting a design outline through all of the resist materials, then selectively removing two of the resist materials at selected points within the outline, and then etching to form an engraved outline and two or more different grain surfaces.

3. That improved method of engraving textile printing rolls which comprises applying a series of diagonally extending lines of a resist material on the surface of the roll, applying a second series of oppositely extending lines of a second resist material on the surface of the roll, coating the roll with a third resist material, each of said resist materials being insoluble in solvents for the other two materials, cutting a design outline through the several resist materials to lay bare a portion of the roll surface, cutting a second outline within the said first outline, removing one of the resist materials from the space included within the first design outline and the second outline and then removing another of the acid-resist materials from the area included within the said second outline and then etching.

4. That improved method of engraving textile printing rolls which comprises applying a resist material of beeswax in the form of diagonallyextending lines on the surface of the roll, applying a second series of diagonal lines of resist material over the said first lines, said second series of lines of acid-resist material consisting of an acid-resistant ink, coating the roll with mercurous nitrate, treating the mercurous nitrate with hydrogen chloride gas to convert the mercurous nitrate to mercurous chloride, cutting a design outline through the mercurous chloride, acid-resistant ink lines and lines of beeswax, cutting a second outline within the first outline, dissolving with ammonium hydroxide that portion of the mercurous chloride coating occurring within the said first formed outline, dissolving with an organic solvent the ink lines included within the said second formed outline, etching the roll, and then removing remaining resist materials from the surface of the roll.

5. That improved method of engraving which comprises selectively applying on the surface to be engraved a resist material, thereby leaving uncovered surfaces which, when etched, will provide a grain, applying a second resist material over the first resist material, thereby to leave uncovered surfaces which, when etched, will present a second type. of grain, each of said resist materials being soluble in solvents which do not affect the others, applying a third resist material over the said first and second resist materials, said third resist material being soluble in a solvent which does not affect the said first and second resist materials, said third resist material being insoluble with respect to solvents for the said first and second resist materials,

removing one or more of, the resist materials at selected. points in the surface of the roll, and etching, thereby to provide a plurality of types of grained surfaces on the roll.

6. That improved method of engraving textiles printing rolls which comprises applying a resist material of beeswax on the surface of a roll to.

5 mercurous nitrate with hydrogen chloride gas to convert the mercurous nitrate to ,mercuroustchloride, removing portions of the mercurous chloride and underlying acid resists, and then etching.

JOHN J.., ORMON

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