US1117490A - Lithographing process. - Google Patents

Description

"UNI

JAMES E. HORNEY, OF BALTIMORE, MARYLAND.

LITHOGRAPHING PROCESS.

No Drawing.

To all whom it may concern:

Be it known that 1, JAMES E. HoRNnY, a citizen of the United States, residing at Baltimore city, State of Maryland, have invented certain new and useful Improvements in Lithographing Processes, of which the following is a specification.

My invention relates to lithographic processes and has for its object to furnish to the art a new and improved process by means of which lithographic printing may be done upon the modern cylinder or rotary press.

For a long time the bulk of lithographing has been done onstone but it has long been known that it could be done on metals such as zinc and aluminum. WVhile conditions in the art called for good work and not so much of it, stone was satisfactory but the last fifteen years have brought about big changes in the art and the demand has become so great for more and quicker work that many efforts have been made to adapt the art to the modern cylinder or rotary press. Under the method now used in lithographing on either stone or metal, the metals are always in a very delicate condition and liable to be spoiled in an instant and the ablest men in the business are at a loss to know why this takes place. A frequent reason for this spoiling is because the greasy portion of the plate is not sufiicientlv protected against all of the acids it is subjected to. In carrying out the known process the metal is placed with the grain side up, which side is sensitive to grease. The transfer-man makes his impressions off the original stone with a paper prepared on its surface with a preparation of starch, flour and glycerin and this impression is put down on the raw surface of the metal plate. The ink is greasv and black. This impression is put upon the grainv side of the metal. face down and subiected to a very heavy pressure. After this the paper is soaked off the plate with water, leaving all of the ink on the plate. Now, the most important work follows. in making the plate ready for the press which is done by etching it with phosphoric acid and by keeping the plate clean, otherwise the plate would become black all over. If it were attempted to etch the plate immediately after the greasv black ink was deposited on it, the acid would burn off the ink, the heat of the acid absorbing the grease, and spoiling the plate. To pre-' Specification of Letters Patent.

Patented Nov. 1?, 1914.

Application filed June 15, 1914. Serial No. 845,103.

pare the plate for etching it is coated with a gum arabic solution, and then dried. With a rag and plenty of ink, more ink is rubbed on the plate until no more can be put on. The plate can now be etched with phosphoric acid, mixed with gum arabic. The plate is again coated with the gum arabic solution and fanned dry after which all ink is washed off the plate with turpentine. The plate is now coated with asphaltum dissolved in turpentine and rolled up with a hand roller to test it. If it stands the hand roller, it will usually stand the steam press rollers but very often, for no discoverable reason, it will not. This is the crucial point in the process and many efforts have been made to make the process certain and satisfactory over this point, but without success.

My improved process begins after the transfer-man finishes his plate under the methods now used. I wash all ink oil the surface of the plate with turpentine while the plate is coated with the gum arabic solu' tion and coat the plate with asphaltum, the same as in the old process up to this point.

Now my object is to protect the greasy surface the lack of which protection has heretofore caused the trouble and I will now fully describe my process from the beginning. I take an aluminum or other equivalent plate, place it grain side up, transfer the original impression on the grained surface, soak off with water, wash off all surplus starch left on the plate from the impression, dry the plate thoroughly, coat the plate with a solution of about one ounce of gum arabic in two ounces of water, and fan the plate thoroughly dry. The plate is then rubbed up with a mixture of black printing ink and about ten drops of linseed oil reduced with a little varnish, first using a little gum arabic solution to moisten the gum while rubbing up the plate which will prevent the plate tinting all over. After the plate is rubbed up thoroughlv all over, it will be in condition to etch with a little acid but before this etching, all scum is washed off, which is floating turpentine used in the ink mixture for rubbing up the plate, and the plate powdered with a French chalk to protect it as much as possible from the acid. y

I now go over theplate with a ,n'iiiiture of one part ofphospho'rie acid and twenty parts of Water, the water dissolves the gum from the plate and the acid cleans the surface of the plate, then thoroughly wash all acid from the plate, thoroughly dry it, and coat it all over the surface with a solution of one part of gum arabic in two parts of water, and fan the plate thoroughly dry. I now vash all the ink off the plate with turpentine until nothing remains but the stain of the grease which was deposited there in transferring the impression. Before washing the plate out with turpentine I see that the gum arabic is thoroughly dry and covers the whole surface of the plate as this is the only protection the plate has from smearing all over. I now coat the plate with a solution of one ounce of asphaltum in about one ounce of turpentine and fan the plate dry. I then wash all surplus asphaltum off with water, the coating of gum arabic beneath the asphaltum, where there is no grease, being dissolved by this water and leaving the asphaltum on the plate where the grease was transferred. I now rub the plate up with a mixture of one part of good transfer black ink and one part of J apanned driers, using a little gum arabic beforehand to keep theplate from smearing all over and then take a hand roller charged with printing ink and roll over the plate once or more in order to sharpen the plate.

It will be noticeable that after rubbing up a plate with this ink and gum arabic, that all the surplus ink must be washed off the plate with water before you can put the roller on and in washing this ink off it will have a tendency to flood and make the plate look smeary. In rolling over it the roller will remove all this smudgy appearance as the work must be as sharp as possible. As the work must be as sharp as possible it is necessary that it must be covered thoroughly with my mixture of ink with the driers, and allow no scum on the plate, for the reason that after my process of drying, it will be impossible to remove it with acid. After the plate is rubbed up and rolled up and is as sharp as it is required to be, I powder the plate with pulverized asphaltum, (the finer the better) and take care to cover the plate thoroughly with this powder as this is ex-' tremely important. I then wash off all the surplus powder with water and expose the plate to a heat of about 250 to 270 degrees for about one and one half hours. Under this heat the asphaltum powder is melted and dries along with the ink and forms my printing ink. It will be observed that instead of printing off the surface of the metal as in the old process, I print from this sticky crust which I have dried there. When the plate comes from this drying process, it can be etched very strongly for the reason that it would be extremely difficult to etch through'this crust by any acid that is used in lithographing. As the acid does not interfere with the printing surface I etch the plate with a mixture of about seven parts of thin gum arabic solution and one part of phosphoric acid and it may be allowed to come to a foam without injuring the plate. I now wash all the acid from the plate with water and gum the plate all over with thin gum arabic, when it is ready for the press. Instead of pulverizedasphaltum, I have produced very good results from pulverized soap stone or talcum powder but I consider the asphaltum to be preferred.

By my process I may print with a'press on tin plate or aluminumsheet metal, and after the ink is printed on a plate by my process, all that would be necessary would be to powder with the asphaltum powder and dry the plate and with the plate dried, with. the powder on it I would have my printing surface. This would be reproducing a plate from a steam press without the Work of the transferman.

While I have specifically described the various steps in my improved process, and the proportions of the materials used, I desire it to be understood that slight changes and variations may be made therefrom, without departing from the spirit and scope of the invention as hereinafter claimed.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent of the United States is 1. An improved process of preparing lithographic plates which consists in transferring the original impression upon the plate, soaking off the paper, washing ofl" surplus starch, drying the plate, coating with gum arabic solution, drying the plate, rubbing up the plate with a mixture of ink, linseed oil and varnish, washing off all turpentine scum, powdering the plate with French chalk, going over the plate with phosphoric acid and water washing all acid from the plate, coating with a solution of gum arabic, drying the plate, washing all ink oil with turpentine, coating the plate with a solution of asphaltum and turpentine, drying the plate, washing off surplus asphaltum and gum arabi'c, rubbing up the plate with a mixture of ink and driers, rolling the plate with a roller charged with printing ink, and finally forming a printing surface on the plate with asphaltum powder melted and dried.

2. An improved process of preparing lithographic plates which consists in transferring the original impression upon the plate, soaking off the paper, washing oif surplus starch, drying the plate, coating withgum arabic'solution, drying the plate, rubbing up the plate with a mixture of ink, linseed oil and varnish, washing off all turpentine scum, powdering the plate with dering the plate with pulverized asphaltum, washing oil all surplus powder, and heating the plate to melt and dry the asphaltum powder, with the ink under it, to form the printing surface.

In testimony whereof I aflix my signature in presence of two witnesses.

JAMES E. HORNEY.

Witnesses:

E. WALTON BREWINGTON, MARY M. MAGRAN.

copier 0t thll patent in be obtained for the cents each, by addressing the, Commissioner of Patents, Washington, D. G."