US2937594A

US2937594A - Lithographic printing

Info

Publication number: US2937594A
Application number: US505840A
Authority: US
Inventors: Jr Carlton B Miesse
Original assignee: Harris Intertype Corp
Current assignee: Harris Corp
Priority date: 1955-05-03
Filing date: 1955-05-03
Publication date: 1960-05-24
Anticipated expiration: 1977-05-24

Description

c. B. mssss, JR 2,937,594

LITHOGRAPHIC PRINTING Filed May 3, 1955 May 24, 1960 INVENTOR.

CARLTON B. MIESS EQJR.

ATTORNEYS i ed S at s atc LITHOGRAPHIC PRINTING Carlton B. Miesse, Jr., Lakewood, Ohio, assignor 'to Harris-Intertype Corporation, Cleveland, Ohio, a corporation of Delaware Filed May3, 1955, Ser. No. 505,840

Claims." (Cl; 101-426) this difiiculty occurs, the customary procedure is to clean the inker and chemically treat the steel roller so as to remove the offending surface layer.

While perhaps not so marked, the same difficulty is enconntered even where the ink roller is provided, with a copper surface, applied either by electroplating techni ques or deposited from a chemical solution. What is said with regard to ink rollers is of course equally applicable to ink-scavenging rollers in the dampening system.

More particularly, in a conventional lithographic print? ing process, a cylinder carrying a lithographic plate is associated with a train of ink-feeding rollers and a train of Water-feeding rollers, the latter being called the dampening system, as illustrated for example in US. Patent No. 2,690,119. As the cylinder rotates, the ink-feeding rollers ink the image areas of the plate, while the waterfeeding rollers dampen the non-image areas in amnner known in the art. The rotating cylinder engages a rotating blanket roller and transfers to it an image corresponding to the inked areas. The blanket roller in the offset type of printing similarly transfers the image to paper orthe like passing between the "blanket roller and a third, impression roller; l I In the present invention, a roller having a surface prepared as hereinafter described may constitute one of the ink-feeding'rollers which passes the ink to the lithographic plate, vor, as above noted, a roller having a surface of the present invention may also be used as an inscavenging roller in the dampening system which,' because .of its ink receptive nature, collects ink which may be picked.up'from the plate by the rollers of the 'dampemng system. H

.Also' related to .the foregoingdifliculty is th-at enc'ou nteredsin the .use .of. lithographic. plates themselves where the b ase of. the plate. is metal sheet or foil that should normally present an ink-receptive surface. I have discovered that a metallic ink-transfer surface, such as any one of those above referred to, and particularly a steel ink roller, can be rendered ink-receptive and waterrepellent by coating the surface in question with copper selenide. I heave further discovered that such a coating can be readily formed by treating the metallic surface with a suitable solution. Where the surface already is formed of copper, the selenide coating may be formed directly by treatment with a dilute aqueous solution of selenious acid. However where the surface is of steel, I preferably employ a dilute aqueous solution of reagents yielding a concentration of cupric ions sufiicient to deposit a film of copper by galvanic action and include in such solution a selenious compound capable of reacting 2,937,594 Patented May 24, 1960 stoichiometrically with such film to produce the desired copper selenide coating. 7

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means herein after fully described and particularly pointed out in the claims.

In the accompanying drawing: r

Figure 1 is a diagrammatic sectional view of printing apparatus, and

Figure 2 is a perspective view of a roller having a surface prepared in accordance with thepresent invention.

Referring to the drawing, the printing apparatus includes a lithographic cylinder 10 cooperating with a train of ink feeding rollers generally shown at 11, and a train of water feeding rollers generally shown at-12. Inkis transferred from an ink duct 13 to. the rollers of train 11 and then to the cylinder 10v in a conventional manner, the cylinder 10 carrying the lithographic plate. Similarly, water is transferred from a trough 14 to the rollers of train 12 and then to the cylinder 10. In particular, an inking roller such as that shown at 15 may have a surface prepared in accordance with the present invention. Also, the lithographic plate on the. cylinder .10 may have printing areas so prepared. A blanket roller 16 and an impression roller 17 pass paper or .the like therebetween which receives an impression from the cylinders 10 and 16 in a well known manner.

The following description sets forth in detail certain approved compositions of matter and methods of employing the same, such disclosed composition and steps constituting, however, but one of various ways in which the principle of the invention may be used.

In general, in carrying out the invention, I may use an aqueous solution consisting essentially by weight of less than 2% of an inorganic copper salt, less than 1% of by drochloric acid and approximately 2% of selenious acid.

The following is a particular formula which has been found quite satisfactory for use as an anti-stripping solution for steel ink rollers, viz.:

Example A v v g Parts Cupric sulphate pentahydrate 1.21 Selenious acid I 1.93 Hydrochloric acid spg=1.19 0.42 Water (deionized) 96.50 Wetting agent 507 The proportion of the foregoing constituents may be ions and a selenum compound yielding the desired con;

centration of SeO The concentration of cupric'ion should be such as to deposit on the metal a continuous film of copper by galvanic action. The concentration of SeO ion must be such as to react stoichiometrically with the deposited copper to produce copper selenide.

The amount of wetting agent should be such as to reduce the surface tension of the solution to a point where the metal being treated is readily wetted by the solution. A reduction of the surface tension of the solution into a range of 40-50 dynes per square centimeter is sufiicient. The chemical composition of the wetting agent must be resistent to the oxidizing action of the selenite radical. Numerous such wetting agents are available in the anionic, cationic or non-ionic types. a The preferred type I for this use is a non-ionic wetting agent which might be an aromatic polyglycol ether condensate such as Neutronyx 600 produced by the Onyx Oil Company.

It is desirable to include an agent which will limit the number of cupric ions available in solution so as to improve the adherence and density of the deposited layer. A convenient material for this purpose is hydrochloric acid.

A solution made up according to the example just given may be applied to the surface of the roller in any suitable way, eg by dipping, spraying, or even brushing, so long as adequate uniform treatment is obtained. The following are additional examples of solutions effective in producing the desired copper selenide surface on steel, although the cost thereof would be somewhat higher than the example first given above, viz.:

Example B Parts Copper sulfamate 1.23 Selenious acid 1.96 Hydrochloric acid spg=1.19 0.42 Water (deionized) 96.40 Wetting agent .07

Example C Parts Copper fluoborate 1.15 Selenious acid 1.92 Hydrocloric acid spg=l.l9 0.42 Water (deionized) 96.30 Wetting agent .07

The comments previously made in connection with Example A as to the range of proportions will of course apply equally to the ingredients entering into Examples B and C. Moreover, it will be understood that in any case, where the metallic ink-transfer surface is already of copper, the copper compound and reacting acid ingredient may be omitted and the solution in such case will consist only of the selenious acid of approximately the indicated concentration, together with the relatively small amount of a suitable wetting agent.

Other modes of applying the principle of my invention may be employed instead of those explained, change being made as regards the products and methods herein disclosed, provided the step or steps stated by any of the following claims or the equivalent of such stated step or steps be employed.

I therefore particularly point out and distinctly claim as my invention:

1. A method of transferring ink to a receiver therefor comprising the steps of applying ink to a surface of a transfer member consisting essentially of copper selenide, and pressing the copper selenide surface against said receiver to transfer the ink thereto.

2. An improved method of transferring ink to a receiver therefore by means of a transfer member comprising the steps of forming on said member a coating of copper selenide to enhance the ink-attractiveness thereof and overcome stripping, applying ink to said coating, and then transferring the ink from said coating to the receiver.

3. An improved method of transferring ink to a receiver therefor by means of a member having a copper surface comprising the steps of treating said surface with a dilute aqueous solution of selenious acid to deposit thereon a coating of copper selenide and enhance the inkattractiveness thereof and overcome stripping, applying ink to said coating, and then transferring the ink from said coating to the receiver.

4. An improved method of transferring ink to a receiver therefor by means of a member having an iron surface comprising the steps of depositing on such sur face a continuous film of copper, reacting the latter with selenious acid to form a coating of copper selenide to enhance the ink-attractiveness thereof and overcome stripping, applying ink to said coating, and then transferring the ink from said coating to the receiver.

5. A method of transferring ink from a first member to a second member having a surface of copper selenide comprising the steps of applying ink to the first member, and then placing the first member against the second mem her to transfer ink to the copper selenide surface thereof.

6. A method of accumulating ink on a scavenging roller comprising the steps of forming on such roller a surface of copper selenide to enhance the ink-attractiveness thereof, and then depositing ink on such surface to accumulate the ink thereon.

7. In a printing press having an inking system provided with an ink transfer member and having a plate member to receive and transfer ink, the improvement wherein at least one of said members has an ink-contacting surface of copper selenide.

8. In a lithographic printing press having an inking system provided with ink transfer members and a dampening system, the improvement wherein at least one of said ink transfer members has an ink-contacting surface of copper selenide to enhance the ink-attractiveness thereof.

9. In a lithographic printing press having an inking system provided with rollers and a dampening system provided with rollers, the improvement wherein at least one of the rollers of said inking system comprises a steel surface united with a layer of copper selenide to improve the ink-attractiveness and overcome stripping of said roller.

10. In a lithographic printing press having an inking system provided with rollers and a dampening system including a scavenging roller, the improvement wherein at least one of said rollers has an ink-contacting surface of copper selenide to improve the ink-attractiveness of said roller.

References Cited in the file of this patent UNITED STATES PATENTS 2,303,350 Fuller Dec. 1, 1942 2,323,424 Schore July 6, 1943 2,408,116 Von Hippel Sept. 24, 1946 2,429,107 Petren Oct. 14, 1947 2,527,232 Scroxton Oct. 24, 1950 2,676,886 Barbarite Apr. 27, 1954 2,701,234 Wernlund Feb. 1, 1955