Patented Feb. 14, 1939 ‘ 2,146,976 UNITED 7 STATES PATENT OFFICE 2,146,976 METHOD OF_ MAKING DUPLICATE COPIES George G. Neidicli, New York, N. Y. - No Drawing. Application February 23, 1937, Serial No. 127,169 10 Claims. (Cl. 41-315) This- invention relates to improvements in In still another process, use is made of a method methods of making duplicate copies, and more known to the art as spirit duplication. In this particularly to improvements in offset duplica process, a master. copy in strong soluble basic —tion methods of making'dupiicate copies of type anilin dyestuif is produced by typewriter, writ 5 grkitten. matter, hand written matter, and the ing or drawing, as in the case of the gelatin e. processes, except that the typewriting, writing, Heretofore several methods have been em or drawing is in mirror reverse. Ordinarily, ployed for producing copies of matter of the use is made of a special carbon paper whose foregoing character, all of which methods‘re active surface is placed in contact with one side 10 suit in the production of duplicate copies of of the master sheet on which the original type master images, which copies are usually produced writing, writing, or drawing is imposed. When on paper contacted in some manner with a master the image to be reproduced is imposed on one having thereon an image of the work to be dupli surface of this master sheet, the other surface , cated, which master contains material quantities thereof, which is in contact with the carbon 15 of strong dyestuff adapted to be transferred to paper, acquires a deposit of the coating material the copies in the steps followed in the different _of the carbon paper according to the’ lines of processes. impress on the blank surface thereof. Thus a -In one method, use is made of what is known mirror reverse copy of the matter to be repro to the art as a hectograph pan. In this method duced is formed on one surface of the master 20 a gelatin compound is disposed in a pan, A sheet by the transfer of the coating material normal master sheet is typewritten, written, or from the carbon paper to the master sheet. This drawn, with an ink strongly colored with basic mirror reverse copy is attached to the‘ drum of dyestu?, usually crystal violet, the master being a spirit duplicator and sheets of copy paper are usually in' the form of a sheet of paper or the fed thereto in succession. Means are provided 25 like. Crystal violet is ordinarily used since this for moistening the sheets of copy paper immedi 26 dyestuff is more powerful and is more quickly ately prior to their contact with the master sheet, soluble than other dyestuif. The master is laid and since the basic anilin dyestuif in. the com on the top surface of the gelatin compound in position on the master sheet is highly soluble. the pan and permitted to remain in contact with the moist surface of\the copy sheets when con so the surface thereof until the compound absorbs ' tactéd with the mirror reverse copy on the master 30 locally suf?cient of the dyestu? to produce at sheet cause the transfer of coloring- matter to least onehundred copies of the matter to be the "copy sheets. In this process, use may be reproduced. The absorption of dyestuff from made of any desired solvent, but preferably the the master is in’ accordance with the lines of solvent used is ordinarily more volatile than 35 the image on the master so that in veffect a mir water, the practice having been to make use of ror reverse copy of the matter to be reproduced alcohol, methanol, acetone, or other similar sol is formed in the compound. Sheets‘ of copy paper vents or combinations ofv solvents. By the use are then contacted with the surface of the com of such solvents, more copies can be produced pound, resulting in the transfer of su?icient dye from a single master, and the copies so produced ' “; stuff from the compound to the copy sheets as are sharper than those produced by the use of to produce copies of the matter desired. ~ water. Moreover, the copy so produced dries This principle has been further extended to almost immediately at normal temperature. a process in which the gelatin composition is , In the practice of all of the foregoing processes, _ V thickly coated on a backing sheet, usually as a certain faults are present which sérve to limit the 45 roll of considerable length fastened to the drum ‘use thereof: Since the processes have required of a two cylinder machine. The same procedure the use of dyestu?- which is highly water soluble,’ - for causing absorption of dyestuff‘ is followed it follows that the handling of the dyestuif in out so that the composition contains absorbed most instances results in stains both to the person ~- ' therein a mirror reverse copy of the original and the clothing of the user. _ For example, the in matter and the surface of the gelatin becomes .~moisture of the-hands of the user alone is suiii ' ’ a printing medium. Copy sheets are fed between cient to transfer material quantities of the dye the master cylinder (having the gelatin surface) stui’f to thehands, and consequently clothing also and a platen cylinder causing transfer of dye-v readily becomes stained, all of which is, highly stuff to the copy sheets and thereby producing undesirable. The ribbons, carbons, or ?uids I. legible copies of'the desired matter. ' which have been used all contain large quantities I‘; 2 2,140,970 .of basic dyestuffs,-such as crystal violet, rho; user since the material which is to be utilized damine, Victoria blue, or Victoria green, all of as color transfer material has of 'itself no ap which are water soluble ‘colors. It is evident, preciable color transfer value and is water in_ therefore, that any process which requires the soluble, but must be further treated to cause it handling of ribbons, carbon paper, or ink of this to acquire high color transfer value. character will produce the objectionable results Use of the present invention therefore can be before set forth. , made in duplicate processes involving the use An object of the present invention is to provide of gelatin, either in a pan or on a roll. In such new methods for producing duplicate copies, processes the normal image of the matter to 10 which methods are free from the objectionable beduplicated, if typewritten, can be made on results before described. _ a sheet of paper through the agency of a ribbon Another object of the invention is to provide of the character before described. ' The gelatin, methods of making duplicate copies, which meth either in the pan or on the roll, can be either ods involve the use of transfer‘material which in impregnated or the surface thereof washed with 15 itself and before further treatment possesses sub a dilute acid in aqueous solution; as for ex 15 stantially no objectionable color transfer value. ample, a ten per cent solution of lactic acid. Another object of the invention is to provide The acid, either on the surface of the gelatin, methods of producing duplicate copies wherein or impregnated therein serves to react with the master copies of the matter being reproduced areJ base of the dyestuff absorbed from the sheet of, 20 formed through the agency of matter having no paper, having the normal image thereon, to con 20 appreciable color transfer value and wherein such vert such base of the dyestuif into basic dyestuff. masters are subsequently treated to cause such Copies may then be'made in the usual manner. material to have high color transfer value. In the adaptation. of the present invention to In carrying out the foregoing and other objects spirit duplicating processes, again the normal 25 of the invention, the present invention contem steps followed in such processes are carried out 25 plates the use of material which in itself possesses with the exception that use is made of carbons, no appreciable color transfer value and which or of powdered ink, which have no appreciable material is of a character as to be insoluble in transfer value, but which must be subjected, to water.’ Consequently, this material may be han a reaction to acquire such transfer value._ A 30 dled in any manner required by the processes "Lmirror reverse copy of the matter to be dupli 80 hereinafter described withoutincurring the liabil cated is formed on a master sheet in any of > ity of staining the person or clothes of a user. the usual manners such as for example, by mak The basic anilin colors which have previously ing use ,of a coated .carbon containing the base been used ‘in connection with carbon paper and of the dyestuif combined with a suitable vehicle. 35 ribbons are in the ‘form of organic salts or esters A mirror reverse image of the matter to be 35 of‘ highly complicated organic radicals. The reproduced may be activated by a small amount present invention makes use of the desirable qual of a relatively weak acid in a number of ways, ities of these basic'dyestuifs without incurring the of which three are hereinafter set forth. undesirable qualities thereof. To this end, in 1. An activated sheet specially prepared is stead of using the basic colors themselves, use is made up of a sheet of paper coated with a satu- ~ made of the bases ofsuch basic colors such as the rated solution of solid .acid, "such as benzoic, in bases of crystal violet, methyl violet, rhodamine, a volatile solution such as alcohol.