US1776015A - Printing plate and process of producing the same - Google Patents

Description

Sept 16, 1930- A. E. VILLAREJO -1,776,015

PRINTING PLATE AND PROCESS OF PRODUCING THE SAMEy Filed Oct. 21, 1929 Patented Sept. 16, 1930` UNITED STATES PATENT OFFICE ALFRED EQ. 'VILLAREJ'O, OF MILWAUKEE, WISCONSIN, ASSIGNOR 0F ONE-HALF TO RUDOLF P ZETTINIG, 0F MILWAUKEE, WISCONSIN PRINTING PLATE AND PROCESS OF PRODUCING THE SAME Application led October 421, 1929. Serial No. 401,032.

This invention relates in general to the production of printing plates by electrodeposition and more particularly ,to the direct production of such plates on a metallic a original.

In applying graining, simulating Wood graining, or other ornamentationto'the metal panels of automobile bodies, it is the usual practice to have a positive metal plate or 1o original on which the graining or design has been produced. In the case of Wood graining, the original metal plate has ridges and valleys, conforming to the contour of the graining. The plate is inked and after any i5 excess of the ink is removed, a roller is run over the plate and then run over the metal panel of the automobile body so that the-design is transferred to the metal panel of the automobile body.

The production of the positive metal plates from which the impressions are transferred by the roller is a source of difficulty and ex pense, especially Where these plates are of any substantial size, as they frequently must be in connection with the graining of, or the application of other ornamentation to, certain automobile panels.

In this art the practice heretofore has been to produce a design on the original metal plate by a photographic (half-tone) process, and then transfer the impression or design from the original to a body of Wax by pressing the body of Wax against the original. The surface of the Wax which has the impression produced thereon in this Way is then coated with graphite and then placed in an electro-plating bath and subjected to the electro-plating process so. that a coating of copper is then deposited over the graphite surface of the Wax. The Wax is then melted out of the deposited plate and this plate is the one thatl is inked and from Which the impression is transferred to the automobile panel by Ithe transferring roller.

One of the principal objects of the present invention is to dispense with the use of the Wax and to deposit the metal in the electroplating bath, directly onto the original metal plate produced by the usual photographic process. The great difficulty that has here- 'unsatisfactory for various reasons such as expense, loss of detail, damage -to theoriginal or the like.

The present invention produces a separating or stripping film on the original in a speedy and comparatively inexpensive manner and does this Without damage to the original and Without loss of detail and yet insures the easy stripping olf of the electrolytically deposited plate.

Other objects and advantages reside in certain novel features which Will be hereinafter more fully described, and particularly pointed out in the appended claims, reference being had -to the accompanying drawing forming a part of this specification and in which:

Figure l is a plan View of an original from which printing plates are to be produced;

Figure 2 is a View in section of line 2-2 of Figure l;

Figure 3 is a figure similar to Figure 2, but illustrating the coating formed on the surface of the original plate which carries the design, the coating being exaggerated for the sake of clearness;

Figure 4 is a diagrammatic vieW` illustrating hovv the negative plate is deposited on the original;

Figure 5 is a vieW similar to Figure 3, showing how the positive printing plate is deposited on the negative plate; and

Figure 6 is a diagrammatic view in perspective illustrating how the inked roller is used with the positive printing plate prod ueed in accordance With the present invention.

Referring then to the drawings, it will be seen that an original metal plate l, preferably of copper, is provided and has a design etched or otherwise formed on the surface 2 thereof bymeans of a conventional photographic process. The surface 2, on which the design is formed or carried, is first subjected to a bath of ammonium polysulphide (NHQgSa, either by immersing the surface 2 in a concentrated solution of ammonium polysulphide or by subjecting it toa light washing therewith, the latter being preferred. The ammonium polysulphide reacts with the copper of the surface 2 of the plate l to produce a very light film or coating of copper sulphide on the surface of the original copper plate carrying the design. After the treatment with the ammonium polysulphide, the plate is dried-atmospheric drying being sufficientand is thenwashed gently with distilled water. Following this the plate is baked to harden the thin film of copper sulphide produced thereon by the ammonium polysu'lphide.

The plate, thus prepared, is placed in an ordinary'electro-plating bath as illustrated diagrammatically in Figure 4 and a shell of copper is deposited thereon in the ordinary way, When sufficient metalhas been deposv ited to make the shell 3 of the desired thick- Y ness, the plate and shell are removed from the bath and the shell 3 is stripped from the original plate 1. The shell will come olf easily due to the use of the sulphide coating on the original plate. The shell 3 is, however, a negative. In order to produce a positive from the shell 3 theprocess is repeated and is identical with the process above described, except that the thin shell 3 must be placed on an appropriate backing shown at 5 in Figure 5 unless it is made sufliciently heavy to dispense with the backing. The shell 3 is, however, treated with -ammonium polysulphide to-produce the thin coating or film of copper sulphide thereon and is then dried, washed, baked and put in an electro-plating bath as illustrated inFigure 5 so that the positive printing plate, or shell 4, is deposited on the shell 3. rlhis shell 4 can also be easily stripped from the shell 3, and may be later usedl as indicated in Figure 6, to vapply the impression to the transferring roller 6 which in turn applies the impression to the panel to be ornamented.

As indicated, ammonium polysulphide is preferably the reagent used to produce the copper sulphide coating as it produces a hard film that will not flake off and that will not impair the design. However, other reagents such as potassium sulphide `or sodium sulphide may be employed to produce the coatmg.

It is to be noted that the copper sulphide coating is formed on and of the metal which constitutes the features of the original design and is an integral part of such features. In other words, the copper sulphide coating is a result of the transformation of the surface metal of the copper plate and consequentl there is no-loss in detail in the design on suoli surface. It is coherent .and will not rub off or be. displaced and as it is a constituent part of the features of the desi n and is of uniform thickness it does not eprive the design of any of its detail, nor does it impair the same in any Way. Further, the

film is a good conductor of electricity so as skill.

The invention claimed is:

1. The herein described process of producing printing plates from an original copper plate which consists in first, subjecting the surface of the original copper plate carrying the design to a bath of ammonium polysulphide to form a thin film of copper sulphide on and as a part of the metal of the plate that constitutes the features of the design, drying and washing the original plate,

baking the original plate to harden the film thereon, then electrodepositing a negative copper plate on the film 'coated original, stripping of the ne ative plate from the original,sim1larly coatlng the surface of the negative plate with copper sulphide, and finally electro-depositing a positive printing plate on the film coated surface of the negative plate.

2. The herein described process of producing printing plates from an original copper plate which consists in first, subjecting the surface of the original copper plate carrying the design to a bath of ammonium polysulphide to form a thin film of copper'sulphide thereon and as a part of the metal of the plate vthat constitutes the features of the design drying and washing the original plate, an baking the original plate to harden the design thereon.

In witness whereof, I hereto alx my signature.

ALFRED E. VILLAREJO.

Images