US567926A - Of same place - Google Patents

Description

UNITED. STATES- OF SAME scnoLz, rL AcE.

PROCESSOF PRODUCING R-ELlEF PLATES FOR PRINTING.

SIEfEGIFIGATION forming part ofLetters PatentNo. 567,

926, dated. September 15, 1896.

Application iiledDeceinber 26,1895. Serial no. 573,390. (in specimens.)

- To all whom it may concern: v I

Be it known that I, O'rrro CAR STRECKER, a subject of the Grand Duke of Hessen, residin g at Mentz, Germany, have invented certain new and useful Improvements in Processes of Producing Relief-Plates for Reprinting Purposes, of which the following is a specification; My invention consists of a process for pro ducin g relief-plates, for reprinting purposes, oi. zinc or aluminium-or aluminium coated with another metal or with an alloy. This process is as follows: Afterthe drawing, reprint, or impression has been applied to a plate of the said metal or a picture has been produced photographieally upon it the plate is etched with diluted salt solutions of heavy metals which are electrically opposite to and hence act on the metal of the said plate, or with mixtures of the said solutions with wit able acids, or with suitable'aeids alone, until the. color-supports, i. 6., those parts of the metal plate which are covered with ink, have attained the required height. In the case of preparing aluminium plates coated with another metal or with an alloy the etchingis to be continued till the surface of the aluminium is reached or is also corroded. For this etching I employ,'preferably, a solution of cupricchlorid or stannous chlorid er a mixture of cupric chlorid with very diluted sulfuric acid or only nitric acid, butl do not limit myself to a peculiar concentration or to a particular salt of metal or to a special acid. After the plate has been etched with the said solution or the said mixture it' is necessary to dissolve or to oxidize those parts of the heavymetals orof heterogeneous substances which adhere to the plate mechanically or are combined with. it chemically. This is attained by treating: the plate with acid, preferably, nitric, acid, the concentration of which depends upon the kind of the etch previously employed. Then the dissolved or oxidized parts are removed by washingthe plate Withwateri .If the plate thus treat d consists whollyof zinc and is designed or bookprintih'g, it needs no further treatment any more than would an ordinary elcetroplate. If, fhoweveiythe plate consists of coated or uncoated aluminium, thenit'is to bepolis'hed with talcia'nd abrush, in case the bined hydrofluoric acids approximately fixed 1) plate ,isroughened, and then the ground, t1 6., the exposed parts of the surface of the plate, Y are to be treated with liqui'dswhich contain phosphoric acids, combined phosphoric acids, hypophosphorie acid,phosphorous acid, hypophosphorous acid, hydrofluoric acid, com

or the oxyaeids of. sulfur, excepting sulfuric acid. By this treatment the exposed aluminium ground is coated with alayer of precipitated aluminium salt, which is insoluble in water, but which absorbs the latter and prevents the spreading of the fatty color. The coated or unf coated aluminium plate is then ready for printing.

. Example 1: Upon an aluminium plate, on which the drawing, reprint, or impression is protected against etching in the usual manner, a solution ofcupric chlorid in water is poured, which contains one part of crystaL lized cuprie chlorid and five parts of water.

Immediately after having done this the solution is distributed equally upon and spread unifori'nlyover the plate by means of a bristle 7 5 brush. A somewhat violent react-ion takes place on thespot, and under development of heat, scum and noise copper is separated in the form ofa blackish-red layer. Immediately after thereaction has been terminated 80. the plate is well rinsed with water. The operation is repeated until the color-support (therelief) has attained the desired or rev quirod height, This height can be previously y employing certain ,85 quantities of the solution. In this case for the calculation of the quantity it is to be noticed that one hundred grams'of crystal lized cupric'chlorid dissolve about nine grams of aluminium. The height of the relief is go ordinarily less than a tenth of a millimeter, which is suificient when printing in a 1ithographic press, but it depends always upon the kind of the work'in question. After the plate has been washed off it has a blackish- 5 red appearance, originating fromthe copper and from the heterogeneous substances. The plate, however, immediatelybecomes of a white color upon dissolving these remains (residuum) with strongpure nitric acid. For

this purpose nitric acid of a standardlof twenty-five to forty-five per cent. is poured upon the'plate, which is washed 0!? subse-.

quently on the spot. Sometimes it is advisable to protect the fatty color or ink which isupon the plate against the influence of the nitric acid, before the latter is poured upon the plate, by heating it or melting it again with colophony, asphaltum, or the like. Then the plate is cleaned and afterward polished absolutely necessary to strengthen the drawing once more with colophony and then. to melt the latter; Instead of proceeding in this manner the plate can first be gummed, then, after the gum has become dry, washed out with turpentine-oil or the like, and finally protectedagain and strengthened, as usual.

Example 3: A plate of aluminium coated or lined with another metal, such as zinc, can

be prepared also in the following manner: The coating of zinc should be freed from all adhering impurities, and then upon or to the surface of the coating of zinc the drawing, reprint, or impression is imposed or applied in the usual manner. Then this drawing, reprint, or impression is strengthened against the influence of acids, as usual, whereupon the parts of the metallic coating which are not protected by the fatty color are etched with an acid which does not corrode aluminium, as, for instance, nitric acid, until the said parts of the coating are removed and the corresponding parts of the aluminium plate are exposed. This etching can be performed in one or more times. In the latter case between two succeeding etching operations the drawing, reprint, or impression is to be strengthened again. To best perform this etching, I usea moderately strong nitric acid. In ordinary cases a diluted etcher of. a standard of five to eight per cent. of nitric acid will answer the purpose, but I do not limit myself to a fixed dilution. been performed the plate is washed out, rolled with fresh color, and treated with a solution of phosphoric acids or the like, as before mentioned,.in order to obtain upon the exposed parts of the aluminium a precipitation of aluminium salt insoluble in water, but absorbing the latter and preventing the spreading of the fatty. color.

Example 4:. If the plate consists wholly of zinc, the preparation is the same as said in the examples 1 and 2, but in this case theexposed parts of the plate need no treatment with a solution of phosphoricacidsorthelike.

Example 5' When the plate is provided After the etching has with a picture by meansof one of the known photographic processes, then it is to be etched in] the manner previously described, after having it protected with resin or the like or not, accordingto the employed process. Subsequently the plate, when required, is to bethe known electromotive series of all bodies.

the heavy metals referred to must be electrically opposite to the metal of the relief-plate.

Having fully described my invention, What I claim as new, and desire to secure by Letters Patent, is-- g 1. A process of producing relief-plates for reprinting purposes, of zinc or aluminium or aluminium coated or lined with anothermetal or an" alloy, consisting in etching a plate of the said metal, after having imposed thereon a drawing, reprint or impression or having produced photographically a picture upon it, with suitable diluted saltsolutions, preferably chlorids, of such heavy metals as are electrically opposite to the metal of the said plate, until the color-supports have attained the required height, and then removing the remains adhering to the plate with suitable acids, substantially as described.

2. A process of producing relief-plates for reprinting purposes, of zinc or aluminium or aluminium coated or lined with another metal oran alloy, consisting in etching a plate of the said metal, after having imposed thereon a drawing, reprint or impression or having produced photographically a picture upon it,

:with a mixture of suitable acids and diluted salt solutions, preferably chlorids, of such heavy metals as are electrically opposite to -the metal of the said plate, until the colorsupports have attained the required height,

and then removing the remains adhering to .the plate with suitable acids, substantially as described.

3. A process of producing relief-plates for reprinting purposes, of aluminium or aluminium coated or lined with another metal plate, until the color-supports have attained the required height, and then removing the remains adhering to the plate with suitable acids, whereupon the ground or exposed parts of the plate after having been polished when required with talc, are treated with-such liquids as will form on the ground a precipitate;

of aluminium salt insoluble in water, but absorbing the latter and preventing the spreading of the fatty color, substantially asdeminium coated or lined with another metal or an alloy, consisting in etching a plate of the said metal, after having imposed thereon a,'drawing, reprint or impression or having 4 produced photographically a picture upon it,

with a mixture of suitable acidsand diluted salt solutions of such heavy metals, as are 7 electrically-oppositeto the metal of the said plate, until the colorsupports have attained the required height, and then removing the remains adhering to the plate with suitable acids, whereupon the ground or exposed .parts of the plate, after havingbeen polishedwhen required with talc, are treated with such liquids as will form on the ground a precipitate of aluminium salt insoluble in water, but absorbing the latter and preventing'the spreading of the fatty color, substantially as described.

5. A-process of producing relief-plates for reprinting purposes of aluminium coated or lined with another metal or an alloy, consisting in etching a plate of the said metal, after 5 or impression or havlng produced photographhaving imposed, thereon a drawing, reprint ic'ally a picture upon it, with an acid, preferably nitric acid, which does not corrode aluminium, until the non-protected parts of the coating are removed and the ground or corresponding parts of the aluminium plate are exposed, whereupon the ground is treated with such liquids, which form on the ground a precipitate of aluminium salt insoluble in water, but absorbing the latter and preventing the spreading of the fatty color, substantially as described. V

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

OTTO CARL STRECKER.