Patented Sept. 7, 1948 2,448,749 UNITED, STATES PATENT orrlca ' Charles H. Van Dusen, Jr., Willoughby, Ohio, as signer to Addressograph-Multigraph tion, Wilmington, DeL, a corporation Corpora~ of Dela ware ' ‘No Drawing. Applicatlon‘lanuary 24, ‘1947, Serial No. 724,231 , _ 4 Claims. (Cl. ‘lob-149.2) This invention relates to print lug. More particularly, this planographic invention relates to '. 2 age thereon, not only e?ectively eliminates‘ or paper planographic printing plates and to a proc prevents the reproduction of any finger prints or resin or rosin particles or so-called resin or rosin ess and solution for eliminating so-called ?nger _ specks in the copies prints and so-called resin specks made from the thus treated 5 paper planographic printing plate but which like wise does not in any way weaken or otherwise interfere with the image-receptive or image-re producing characteristics ot. the various plano 10 graphic image-forming materials which may be employed in forming images on the treated pa ' As is well known in the art of planographic printing paper planographic printing plates, such per planozraphic printing plates including type .as those which ,wr'iter image-forming materials, planographic image-forming inks, and the like. Accordingly, an object of the present inven _tion is to provide a novel process and .solution vfor eliminating and preventing the reproduction of ?nger prints and so-called resin and rosin specks in the copies made from paper piano 20 graphic printing plates. Another‘ object of, the present invention is to provide a novel process and solution for elimi are frequently encountered in the copies made from paper planographic printing plates. These rosin specks are also receptive to the greasy or fatty acid-containing inks used in planographic 30 ages on such paper planographic printing plates including planographic image-forming typewriter , ribbons, inks, crayons, and the like. An additional object of the present invention specks in the copies made from paperplanm, graphic printing plates. However, insofar as I am aware of all of such materials have either ' been unsuccessful in eliminating the reproduc 40 weakening the image-reproducing characteris- _ tics of the image form ed on the master paper pianographic printing plate by means of the vari ous planographic image-forming materials used .for this purpose and which include typewriter image-forming inks, . ing crayons, andlthe like. image-reproducing characteris materials forming images on ' paper planographic printing plates including planographic image-forming typewriter ribbons, , inks, crayons, and the like. In the practice of , In and as the present invention I have, how ever, found a material which when applied as a water solution thereof to a dry or to a wet paper planographic printing plate, and the plate then dried, preparatory to placing a lithographic im brushing,’ spraying or otherwise applying the 55 solution thereto. The t 2,448,749 centage, namely, ?ve per cent, by weight, of 2 preferably run between a pair of squeeze rolls amino, 2 methyl, 1,3 propanediol in water is the ‘ and allowed to dry whereupon it may be pro optimum percentage when the new solution is _ vided with a lithographic image by means of applied to a dry paper planographic printing plate or mat. I have likewise _ found that when_ any suitable lithographic image-forming mate rial, such as any of those hereinbefore referred to, and then treated with an aqueous plano graphic etching or dampening solution to condi tion the plate for use in a planographic print ing operation. The resulting plate is thus va paper planographic printing plate impregnated the new solution is applied to a wet paper plano graphic printing plate or mat the concentration of the solution and the quantity thereof applied is then preferably adjusted so that the resulting 10 solution, thus diluted with and by the water in with 2 amino, 2 methyl, 1,3 propanediol. ' I ‘ It has been found that parchment or like paper planographic printing plates treated with the the wet paper planographic printing plate to which it is applied, is equivalent to a five (5) per cent solution, by weight, and when so controlled produces highly satisfactory solutions on paper new solution not only do not reproduce ?nger planographic printing plates impregnated there prints or resin or rosin specks in the copies made 15 with. However, the exact amount of the ma therefrom ‘but have good image-receptive and terial to be incorporated in a parchment or like good image-reproducing characteristics and that paper planographic printing plate depends upon the new solution does not in any way weaken or and may be adjusted to variable conditions in otherwise interfere with the image-reproducing cluding the condition of the sheet at the time the characteristics of the planographic image-form 20 material is applied thereto, that is, whether wet ing material employed in forming the image or dry, its moisture content if nominally a so thereon. The effectiveness of the new process and so called dry sheet, prevailing atmospheric or room humidity conditions, and the like. lution were demonstrated by applying the new It will thus be seen from the foregoing de solution to approximately one-half of the surface 25 scription that the present invention provides a area of the printing surface of a parchment novel process and solution for eliminating both planographic printing plate which was known to ?nger prints and rosinv specks in the copies re reproduce rosin specks due to the naturally oc curring wood rosin therein. The other half of produced from paper planographic printing plates treated with the new solution, and without in the printing surface of the said parchment plate 30 terfering with either the image-receptive or the was allowed to remain untreated. The thus image-reproducing characteristics of paper plan treated parchment plate was then thoroughly de ographic printing plates treated with the new hydrated at room temperature and then ?nger solution, and thus provides a paper planographic printed throughout its entire printing surface in printing plate having the desirable advantages 35 cluding both the treated and the untreated areas and characteristics, and which accomplishes its thereof. One section of the thus treated parch intended objects,‘ including those hereinbefore ment plate was thereupon exposed to natural pointed out and others which are inherent in diffused sunlight for a period of about four min the invention. ' . utes and theother section was exposed to the I claim: rays of an ultra-violet lamp for a period of ?f 40 1. A paper planographic printing plate im teen minutes. (Both of these treatments are pregnated with 2 amino, 2 methyl, 1,3 propane known to exaggerate the image-reproducing characteristics of ?nger prints upon and of wood rosin specks in parchment or like paper plano ' diol.. 4 2. A parchment planographic printing plate impregnated with 2 amino, 2 methyl, 1,3 propane graphic printing plates.) After having been thus 45 diol; exposed a lithographic image was applied to each 3. A paper planographic printing plate im section of the plate, by means of a suitable'litho pregnated with the dried residue of a ?ve per graphic image-forming material, whereupon both cent water solution of 2 amino, 2 methyl, 1,3 sections of the thus treated and exposed parch 50 ment plate were treated with an aqueous plano 4. A parchment planographic printing plate graphing etching and repellent solution, fas impregnated with the dried residue of a ?ve per propanediol. . ' ~ , tened in position of use upon the plate cylinder cent water solution of 2 amino, 2 methyl, 1,3 of a rotary offset planographic duplicating press, propanediol. ' and a satisfactory edition ofcopies run there 55 from. However, the copies reproduced .from those CHARLES H. VAN DUSEN, JR. portions of‘ the parchment planographic printing REFERENCES ,CITED plate which 'was treated with the'tnew solution did‘ not exhibit either ?nger prints- or so-called The following references are of record in the rosin specks whereas both ?nger prints and rosin specks appeared prominently in the copies re-, 60 ?le of this patent: UNITED STATES PATENTS produced from the untreated portions of the plate. Moreover, that area or section of the new plate which had been treated with the new solu tion exhibited equally as goodlimage-reproducing characteristics and equally as long editions were 65 reproduced therefrom as were exhibited by and reproduced from the other area or section of the plate which had not been so treated. It has been found that the above named per Number 2,373,287 Name, v Date Bassist __________ __ Apr. 10,-1945 OTHER REFERENCES Chemical Industries, vol. XLV, p. 666, The Ni tropara?ins and their Derivations, December '7, 1939.