US2321140A - Method and apparatus for printing - Google Patents

Description

June 8, 1943. w, GRUPE 2,321,140

um'rnon AND APPARATUS FOR PRINTING Filed Dec. 28, 19:59

IN VENT 0R M4 04M 6A up ATTORNEY Patented June 8, 1943 METHOD AND APPARATUS FOR PRINTING William F. Grupe, Lyndhurst, N. J., assignor to Interchemical Corporation, New York, N. Y., a

corporation of Ohio Application December 28, 1939, Serial No. 311,349

8 Claims. (01. 1o1 41s) This invention relates to printing, and particularly to an improved method and apparatus for printing which will insure rapid drying of the printed surface, and which will minimize or entirely prevent offsetting.

Film forming compositions, such as printing inks, are applied to webs and sheets of paper, textiles and the like-in a liquid state, and are dried by conversion into solid form. Depending upon the ingredients included in the film forming composition, the conversion required for drying usually may be effected by cooling, oxidation, evaporationof solvent, or polymerization. However, recently it has been suggested that printinginks, for example, may be dried or set by incorporating into the wet film of ink a thickener which is soluble in the film. The thickener orsetting medium is preferably one for which the ingredients of the ink film have a low solvent volatile solvent which is miscible with the film vehicle. Then upon evaporation of the added solvent, the mixture in the film changes from the liquid state to the solid and thus dries.

Heretofore the wet. ink has been impregnated with the thickener or setting medium by spraying the latter upon the freshlyprinted sheet or web or applying it thereto with a conventional coating roller. This manner of application causes the loss of large quantities of the sprayed or coated material and has other disadvantages. One particularly important disadvantage is that the type of material now used tends to repel the presently used adhesives so that the finished sheets or web cannotbe used subsequently in making up bags immediately after application there will be no danger of offsetting. My improved method comprises applying a, film of printing ink and a film forming or setting material which is soluble in the ink to a printing member, and then transferring the ink and the film forming material to the surface of a sheetv or web. This method may be practiced either by applying the film forming material to the type before the ink is applied, or by applying it directly after the ink is applied, and, due to the fact that the press is operating at high-speed and the consequent lack of time to lose or evaporate any solventin the film forming material, setting of the ink will not take place until it has been transferred to the sheet which may be subsequently heated, if desired. The application of the film forming material may be accomplished by means of a suitable coating roller which is adapted or positioned to apply the material either directly before or directly after inking of the type. In this manner, the ink setting material is only applied to the printed matter and a great saving is effected.

The above and other features and objects of the present invention will becomeapparent upon consideration ofthe following detailed description and the accompanying drawing in which: Fig. 1' is a diagrammatic side elevaticnal view of an apparatus embodying my invention and useful in the practice of that form of my method in which the ink setting material is applied after the type hasbeen inked;

Fig. 2 is an enlarged fragmentary vertical elevational view of a part of the apparatus illustrated in Fig. 1; and

Fig. 3 is a diagrammatic side elevational view, similar to Fig. 1, showing a modified form of apparatus embodying my invention, and in which the ink setting medium is applied in a film to the type prior to the inking thereof.

Referring-now to the drawing, it will be observed that a web ll], of paper or other suitable material to be imprinted, is fed from a suitable supply roll l2 by means of conventional feed rollers it through a printing unit It. The printing unit l8, which'may be of any suitable construction, includes an impression cylinder It, a. cooperating plate or printing cylinder 20, and an ink applying and distributing system of rollers 22. The ink applying and distributing system of rollers 22 functions to a ply a uniform film'24 of ink of the desired thickness to the type 26 of the printing cylinder 20 as indicated in Fig. 2 and, in the ordinary printing press, such film would be applied in the usual manner to the web in during operation of the press. In the present construction, however, I have provided a coatin roller 28, which is positioned between the ink applying rollers 22 and the web, for modifying the conventional practice in accordance with my insetting material which has been found suitable for application in the manner herein described, is that disclosed in Adolph J. Pingarron Patent No. 2,249,782, dated July 22, 1941, and consists of solutions of a rapidly volatilizable solvent miscible with the ink vehicle and a dissolved film forming solid. for which the ink vehicle has a low solvent power. A specific solution of this character, which may be used for drying a conventional linseed oil ink, may comprise a five percent solution of high viscosity (1000 centipoise) chlorinated rubber (sold under the trade name Tornesit" in toluol. The solution of chlorinated rubber mixes with the wet ink film, and

- upon evaporation of the toluol, which occurs in a few seconds, the film becomes a. dispersion of pigment in a solution of chlorinated rubber in the particular linseed oil used in the ink. Since such solutions are highly viscous masses at room temperature when the amount of chlorinated rubber exceeds one pe'rcent, and since such viscous masses, when pigmented, are essentially solid, the ink is dry when the toluol evaporates. Although further drying occurs by oxidation, the ink is dry enough to permit reverse side printing within a few seconds after the chlorinated rubber solution has been applied.

During normal operation of the ordinary printing press, such as that shown in Fig. 1, the application of the ink setting material to the type in the manner described and the subsequent application of the ink thus treated to the upper surface of the web 0 will cause the ink to set rapidly so that said web may be subsequently severed into individual sheets and delivered without smudging or offsetting. However, when the press is operating at speeds above one hundred feet per minute, even though some of the solvent is absorbed by the paper, it may be desirable to provide a means 36 beyond the printing unit 16 for directing a blast of heat upon the printed and treated surface. This heat may be advantageously applied by means of an ordinary gas burner adapted to produce an elongated flame or it may be applied in the form of a blast of hot air, either of which is adapted to drive of: the remaining solvent without raising the temperature of the sheet over 200 F. Being thus thoroughly dried the printed web may be given any desired subsequent treatment, or it may be rewound upon a suitable rewind roll stand 38.

In Fig. 3, I have shown a construction similar in all respects to that shown in Fig. 1, except that the ink setting material is applied to the type immediately after printing and prior to inking, rather than subsequent to inking as in the Fig. 1 construction. As shown in Fig. 3, a web 40 of paper, or other suitable material to be printed, is fed from a suitable supply roll 42 by means of conventional feed rollers 44 to a printing unit 46 which includes a printing cylinder 48 and an ink applying and distributing system 50. A coating apparatus 52 of any suitable construction is D0- sitioned on the right hand side of the printing or plate cylinder 48 for applying a film of ink setting material to the type prior to the inking of said type by the ink applying and distributing system 50. With this construction the ink setting medium will first be applied and then the type will be inked and the combined ink and ink setting material is applied to the web during operation of the printing press. As in the Fig. 1 construction, the printed web may be given a heat treatment by a suitable heating device 54 prior to its being rewound upon a rewind reel 56.

From the foregoing, it will be understood that with either the Fig. 1 or Fig. 3 construction, the type of the plate or printing cylinder is coated with a film of ink and with a film of ink setting material and the two films are then transferred to the surface of the material being printed. By operating in this manner, there is a saving of at least twenty percent of the ink setting material that would be used in the prior methods of setting ink, and the ink setting material is only applied to the ink so that all unprinted portions of the sheet willbe completely clean and receptive to adhesives or other materials that may be applied or used thereon in the subsequent treatment of the web.

While I have described preferred embodiments of the apparatus features of my invention, and have shown a conventional double roller type of coating apparatus for applying the film of ink setting material, it will be readily understood that other forms of coating apparatus may be used in the practice of my invention. Moreover, various other changes may be made in the apparatus or method herein described and certain features or steps thereof may be employed without others, without departing from my invention or sacrificing any of its advantages.

What I claim is:

1. A method of printing which comprises applying a film ofprinting ink and a film of a film forming material which is soluble in the ink to a printing member, and then transferring the ink and film forming material to the surface of a sheet or web.

2. A method of printing which comprises applying a film of ink to a printing member, incorporating into said ink a film forming solid which is soluble in the ink and causes it to set, and then transferring the thus treated ink to the surface of a sheet or web.

3. A method of printing which comprises applying a film of an ink setting medium to a printing member, applying a film of ink to said printing member, and then transferring both of said films to the surface of a sheet or web.

4. Apparatus for printing, comprising a printing cylinder having type thereon; an impression cylinder cooperating with said printing cylinder; an ink distributing system for applying a uniform film of ink to said type; roller coating means, disposed adjacent said printing cylinder between said ink distributing system and the impression line between the printing and impression cylinder in the direction of rotation of said printing cylinder, for applying a film of an ink setting medium to the inked type; means for feeding a web between said printing and impression cylinders; and means for applying heat to the freshly printed web.

'5. A method of printing which comprises applying a film of printing ink and a film of a film forming material which is soluble in the ink to a printing member, transferring the ink and film forming material to the surface of a sheet or web, and applying heat to said sheetor web.

6. A method of printing which comprises applying a film of ink to a printing member, adding to said film a solution of a rapidly volatilizable solvent miscible with the ink vehicle and a dissolved film forming solid for which the ink vehicle ha a low solvent power, and then transferring the thus treated ink to the surface of a sheet or web.

7. A method of printing which comprises applying a film of linseed oil ink to a printing memsaid sheet or web.

WIILIAM F. GRUPE.

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