US522719A - John mullaly - Google Patents

Description

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- l to'w u w JOHN MULLALY, OF'NE'W YORK, N, Y. y

PROCESS OF PREPARING SU RFACE-PRINTING PLATES.

SPECIFICATION forming part of Letters Patent No. 522,719, dated July 10, 1894.

Application filed June 13,1893. Serial No.477. 482. (N specimens.) I r i 5 I e T0 all whom i may concern: former. In fact the difficulty of procuring I Be it known that I, JOHN MULLALY, a citisufiiciently pure aluminium commercially, zen of the United States, residing in the city, and the cost of the same, render my process l county, and State of New York, have invented of eliminating the impurities from the surface p 5 certain new and useful Improvements in Proof a plate in which aluminium predominates cesses of Preparing Surface-Printing Plates, of especial importance in the art. of which the following is a description, suffi- In carrying out my invention I form the .cient to enable others skilled in the art to surface printing plate from a suitable (luau 6 which the invention appertains to use the tity of aluminium, procured commercially or to same. otherwise, in the usual manner. After the My improvements relate especially to the plate is in shape I treat the SllIfl0Q ;11p0H class of surface printing plates set forth in the which the design is to be imposed to a washpatents issued to John Mullaly and Lathrop or bath of a dilute acid having little or no L. Bullock, No. 459,239, of September 8, I891, affinity for aluminium,a s nitric, or other acid, I5 No. 476,759, of June 7, 1892, and No. 483,498, which will attack the iron and'bther impuri- V of September 27, 1892, in which the essential ties ordinarily permeating common alumiuifeature consists in forming the plate mainly um, combining with them so that they'may v of aluminium- In order to attain the best rebe washed out and away without aifecting the sults with these aluminium surface printing pure aluminium. This treatment with acid. 20 plates it is desirable that the aluminium be may be resorted to either before or after the practically free from impurities, especially graining of the plate, but must be prior to the V i those which oxidize readily, and difficulty has impiiition of the design otherwise the latter l been experienced in procuring sufficiently will be injured by the acid. Iprefer however 5 pure metal, certain impurities developing to grain thesurface of the platebefore elimii 25 specks upon the plate during its manipulamating the surface impurities since the opera-[. 1

- tion which were apt to take the ink and so tion of graining cXp2QSthe surface impuri- E 7 mar the impression taken from the surface of ties more effectually to the action of the acid i s the plate. After careful investigation and without impairing the grained surface.

experiment I have devised a method of ob- I am aware that acids have heretofore been 3 Viating this difiiculty, and my invention conused in connection'with printing surfaces for 'sists essentially in removing the impurities the purpose of etching the stone or plateitself. 1; '1 at the surface of the plate, prior to the im- The object sought and attained by my invenposition'of the design to be printed theretion is just the reverse of this. I purposely from, by means of an acid against which the employ an acid that will not affect the alualuminium itself is proof. By this means I. miniurmbu w1 attack various impuriam enabled to prepare and use successfully tieseix posed'i nfiie spraceo comm rcla y and continuously in surface printing an alunlifniii'm 'a'fi'dfembve them'without'disturbing I V minium plate that would otherwise be useless or impairing the surface of the aluminium on go for the purpose on account of impurities. which .the design is to be imposed. There is Absolutely pure aluminium is an article diftino etching of the plate itself; by my inven- I cult to obtain commercially, so that by overtion I have simply rendered what is known as ,7 1 coming'the objection to the use of the inferior commercial algpjnigm, as distinguished from v or contaminated aluminium obtainablein the laboratory or chemically pure aluminium, market,Inot only perfect but also cheapen the suitable for surface printing by quickly and surface printing plate, while attaining results cheaply removing from the surface thereof I that are more certain and uniform in so far as the exposed impurities that would otherwise theprintsare concerned. Thusby myprocess takethe-ink and impair the prints taken an inferior grade ofalurninium may be used therefrom. p

loo 1 p 1 in the formation of a surface printing plate In carrying out'my invention Ihave found f 5o and made to give as good results as a plate that nitric acid, diluted with ten to twenty per; j .made from practically pure aluminium,which cent. of water, is convenient and efiective in. 1 latter would cost several times the price of the treating the plates, The strength of the solution, and the length of time in which the plate 1s subjected to the action of the acid solutron vary with the grade of aluminium under treatment, there being several commercial grades of the metal. The purification of the prlnting surface is eifected by either spreadng the acid solution over such surface or by lnimersing the plate bodily in the solution, the surface being exposed to the action for several hours, sometimes for twenty-four, if the plate is of low grade.

What I claim as my invention, and desire to secure by Letters Patent, is-

The process herein set forth of preparing aluminium plates for use in surface printing, consisting in subjecting the surface upon which the design is to beimposed to the action of an acid which will not affect the aluminium but which will attack the exposed impurities so that they may be removed prior to the imposition of the design substantially in the manner and for the purpose described.

- JOHN MULLALY.

Witnesses:

GEORGE WILLIAM MIATT, D. W. GARDNER.