US1982967A

Printing element and process of making same

Abstract

This record has no abstract on file.

US1982967A, drawing sheet 1 — Sheet 1 of 4

Term

Term ended

Expired 4 December 1951, 74.8 years ago.

5 claims: 5 independent, 0 dependent

1
. I claim:— 1. The process of making intaglio printing elements, consisting in flowing a metal base with a light sensitive coating capable of producing-an 90 etching resist, exposing, said coating through a screen, developing said coating, drying the screen image remaining on said base, etching said base to provide ink retaining cells therein, applying a photographic emulsion.to said cells, 95 drying said emulsion, exposing said emulsion through a photographic transparency, developing the exposed emulsion to produce varying thickness in said cells in proportion to the exposure received, and drying the emulsion in said 100 cells.
2
The process of making Intaglio printing elements, consisting in flowing a metal base with a light sensitive coating capable of producing an etching resist, exposing said coating through a 105 screen, developing said coating, drying, the screen image remaining on said base,· etching said base to provide ink retaining cells of substantially uniform depth therein, applying a photographic emulsion to said cells, drying said 110 emulsion, exposing said emulsion through a photographic transparency, developing the exposed emulsion to produce varying thickness in said cells in proportion to the exposure received, and swelling and drying the emulsion in said cells. 115
3
The process of making intaglio printing elements, consisting in flowing a metal base with a light sensitive coating capable of producing an etching resist, exposing said coating through a screen, developing said coating, drying and bak- 120 ing the screen image remaining on said base, etching said base to provide ink retaining cells therein, applying a photographic emulsion to said cells, drying and shrinking said emulsion, exposing said emulsion through a photographic 125 transparency, developing the exposed emulsion to produce varying thickness in said cells in proportion to the exposure received, and swelling ahd drying the emulsion in said cells.
4
The process of making intaglio printing ele- 130 ments, consisting in providing a metal base with ink retaining cells of substantially uniform depth, applying a photographic emulsion to said cells, drying said emulsion, exposing said emulsion through a photographic transparency, de- 135 veloping the exposed emulsion to produce varying thickness in said cells in proportion to the exposure received, and swelling and drying the emulsion in said cells.
5
Thd process of making intaglio printing ele- 140 ments, consisting in providing a metal base with ink retaining cells of substantially uniform depth, applying a photographic emulsion to said cells, drying and shrinking said emulsion, exposing said emulsion through a photographic trans- 145 parency, developing the exposed emulsion to produce varying thickness in said cells in proportion to the exposure received, and swelling and drying the emulsion in said cells. BENJAMIN L. SITES. 150 ing, I have illustrated one manner of carrying out my invention according to which the base 10 such as a copper plate, is flowed with a coating 11 of bichromated gelatin or bichro5 mated albumen, see Figure 2, whereupon this coating 11 is exposed through a rotogravure screen 12 having transparent portions 13, see Figure 3. Figure 4 illustrates the printing element after 10 it has been exposed through a screen; the portions 14 representing the exposed areas while the portions 15 show the unexposed areas, which corresponded with the opaque sections of the screen and which during the development proc15 ess will dissolve so that the exposed portions 14 only remain on the base, such as is shown in Figure 5. After developing, the plate will then be subjected to the’ etching process during which the 20 ink carrying cells 16, see Figure 6, will· be formed. These cells, as explained above, will all be of the same, or approximately the same depth and will then be flowed with a silver emulsion such as a silver bromide gelatin photo25 graphic emulsion 17, see Figure 7. ' This emulsion, after having been thoroughly dried and thus solidified, will then be exposed through a photographic transparency 18, Figure 8, and then developed and swelled as explained above, 30 whereby the high lights i. e. light tones will be represented by the areas 19, which carry little or no ink at all, whereas the deeper tones will be represented by the more ink carrying cells 20 as shown in Figure 9. 35 While I prefer to etch all the cells of the screen image to an even depth, it is not essential to devote much care to that part of the process, because the ink retaining capacity of each cell is determined by the emulsion as explained^ and 40 therefore minor variations in the depth of these cells will not affect the ultimate result. It will be apparent that my process of making rotogravure printing elements will offer the following principal advantages:45 1. The use of carbon tissue will be entirely dispensed with. 2. Errors may be readily corrected, or new designs applied, by washing out the emulsion in the ink carrying cells and by repeating the flow50 ing of the cells with emulsion and subsequently exposing and developing. This does not destroy the copper cells. 3. The etching of the base does not require the usual skill since a slight variation in the depth 55 of the cells produced does not result in any defect in the finished plate. 4., The swelling action of the gelatin can be controlled with less skill than is now required for etching through carbon tissue. 60 5. The exposure of a plate can be readily accomplished in a step and repeat machine, thereby attaining perfect register for multicolor work. As an alternative, that is to say, instead of flowing the ink carrying cells by a silver emul65 sion and then swelling that emulsion as hereinabove described, I find that equally satisfactory results can be obtained by flowing said cells with bichromated gelatin, in which case, however, the cells would have to remain filled, that is to say, 70 the gelatin in the cells must not be below the plane of the printing element i. e. screen image when the gelatin is dry i. e. solidified and at the time when it is exposed through a photographic transparency. 75 According to this scheme, instead of the emul-

Independent claims5

28 paragraphs in 2 sections, as filed

Dec. 4, 1934.

b. L sites 1,982,967

PRINTING ELEMENT AND PROCESS OF MAKING SAME Filed Oct. 9, 1931

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Patented Dec. 4, 1934

1,982,967

UNITED STATES PATENT OFFICE

1,982,967

PRINTING ELEMENT AND PROCESS OF MAKING SAME

Benjamin L._ Sites, Chicago, Ill., assignor to The Miehle Printing Press & Mfg. Company, Chicago, Ill., a corporation of Illinois

Application October 9, 1931, Serial No. 567,776

Claims. (CL 95—5.6)

My invention pertains to printing surfaces and more specifically relates to a process of producing printing elements such as are used in rotogravure i. e. intaglio printing.

® On printing surfaces used in that method of printing, the subject matter or image to be printed is represented by ink retaining cells of a depth that will vary in accordance with the depth of the color tones to be reproduced, that 10 is to say, the deep tones of a print will be produced by those cells which carry most ink, while the lighter tones are represented by the shallow, less ink carrying cells.

Heretofore intaglio printing surfaces were pro15 duced by the delicate and cumbersome carbon tissue method according to which method a carbon tissue, such as regular commercial carbon paper, after it has been sensitized, is exposed through a screen and through a photographic 20 transparency. The exposed tissue is then squeegeed onto a carefully prepared base such as a sheet of copper, whereupon the base is subjected to a dissolution treatment and etching process as is well known in the art.

25 The principal object of my invention is to eliminate the use of carbon tissue and to thereby very substantially simplify the old methods of producing intaglio printing elements.

According to my invention, it will also be pos30 sible to correct errors that might occur during the preparation of a printing element, or to change designs by retaining the same base, a feature which it was impossible to accomplish heretofore. In order to attain these and other 35 objects which will become apparent from the following description and appended claims, I conceived a scheme of providing the surface of a printing element with ink carrying cells which are all of the same, or approximately the same, 40 depth, and to then determine-the ink carrying capacity of the cells by applying thereto a material different from that of which the base itself is made, preferably a photographic emulsion which, after having been exposed and de45 veloped, will leave in the cells deposits qf unequal depth corresponding to the various color tones required.

According to my invention I propose to pro50 ceed for example by flowing a printing base such as a sheet of copper or a copper cylinder with a film of bichromated gelatin or bichromated albumen, generally termed bichromated colloid, which film I subsequently expose through a ro55 togravure screen and then develop it with warm water in the usual manner, so that a screen image will remain on the' base. Preferably the developed screen image is then baked so as to form a permanent resist. Thereupon I etch the 60 base with ferric chloride which will produce ink retaining cells, all of which are of approximately the same depth.

It will be readily understood that instead of providing the screen image on the printing base by the etching method as explained above, the 63 same result could be accomplished mechanically such as by impressing or rolling a screen image into the surface of the base. If produced in this manner, the walls of the cells become hardened by the physical contact of the tool used for 70 this purpose.

This would afford a decided advantage over the etching process because thereby the surface of the printing element will be rendered more resistant to the wear of the doctor blade which 75 is generally used, for scraping the surplus ink off the printing surface of the element prior to effecting the impression.

The cells of the screen image are then flowed with a silver bromide gelatin photographic emul- 80 sion in a dark room and squeegeed off so that the emulsion will remain in the cells only. This emulsion will then be shrunk and thus solidified by drying or by any other practical method so that eventually its level will be below the plane 85 of the screen image.

After this silver bromide gelatin emulsion is shrunk i. e. solidified, I expose it through a design carrying· transparency such as by contact in a vacuum frame, which exposure requires but 90 a few seconds.

After exposure the emulsion in the cells of the copper plate or the like will be developed by any desired method, for instance in a photographic developer so that the emulsion remaining 95 in the cells will be of varying thickness in proportion to the exposure received, and after developing the emulsion which remains in the cells will be swelled either with an alkaline or an acid solution. I have found that the swelled 199 condition of the silver bromide gelatin emulsion can be rendered permanent by immersing the plate i. e. exposed surface into a solution of alcohol, alum and formaline. Subsequent drying of the surface by heat will cause the 105 swelled emulsion to become hardened. By this swelling process the emulsion in those cells jvhich correspond with the high lights of the subject, will completely fill said cells, so that no ink retaining depth will be provided in these cells. 110

Another method whereby the swelling of the emulsion can be arrested i. e. rendered permanent is that of saturating the swelled emulsion with a solution of sodium silicate and subsequently precipitating silica in the gelatin with 115 acid; or, saturating the swelled emulsion i. e. gelatin with a solution of a salt and subsequently. precipitating an insoluble compound by the addition of a precipitating agent.

In Figures 1 to 9 of the accompanying draw- 120

1,982,967 sion in the cells becoming swelled as explained above, those portions of the screen image which during the exposure through the photographic transparency were not exposed to the light will dissolve and wash out so that a printing element 80 identical to that illustrated in Figure 9 will be produced.

It is therefore my intention to cover any such modifications in the process of making printing elements that will come within the scope and 85 essence of the appended claims.

Contents2

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Citations
Document	Relation	Office	Cited during
US4366235A	Cited by	United States of America	Search report
US5587261A	Cited by	United States of America	Search report
US4362806A	Cited by	United States of America	Search report
US3589289A	Cited by	United States of America	Search report

Document	Office	Kind	Date
56777631	United States of America	A	1931-10-09
US19310567776	–	–	–

Printing element and process of making same

Abstract

Term

UNITED STATES PATENT OFFICE

PRINTING ELEMENT AND PROCESS OF MAKING SAME

Priority claims2

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