US1733343A - Process of producing printing plates - Google Patents

Description

Patented Oct. 29,1929- warren A STATES PATENT OFFICE ROY V. GRAVES, OF MINNEAPOLIS, MINNESOTA, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, TO THE GRAVES PROCESS, INC., 0]? MINNEAPOLIS, MINNESOTA, A

CORPORATION OF DELAWARE IROCESS OF PRODUCING PRINTING- PLATES No Drawing. Application filed June 10, 1926, Serial No.115,129 Renewed December 3, 1928.

My inventionhas for its object to provide a new and economical process for the production of printing plates having unshrunk type in high relief capable of use for printing purposes, in substitution for hand set type, machine set type, machine cast and settype, or'machine cast and set slygs.

The said process, in its preferred form. is hereinafter described and pointed out in the claims. In carrying out my invention, I first produce a translucent master sheet containmg the desired composition in opaque impressions. A good quality of white bond paper is suitable for the purpose; and one way of getting the opaque impressions of the composition is by writing out the composition withthe use of a suitable typewriter on the face of the sheet of bond paper with a carbon faced to the back of the bond paper, which will have the effect of producing the composition right sideup on the face of the sheet of bond paper and reversed on the back of said sheet of bond paper or in print and counterprint; and, when this has been done,

one suitable form of translucent master sheet will be available.

It is a matter of convenience also to produce, at the sametime, on the typewriting machine, a proof of the composition. which can be readily done by placing an additional carbon against the face of an additional copy a sheet of paper behind the first carbon above .noted.

The Hammond, multiplex typewriting machine is well adapted for use in producing this master sheet.

The special reason for producing the composition right side up on the face of the master sheet and reversed on the back of said.

machine with the proper kind of properly inked ribbon should be employed. The essen tial point is, that the impressions of the composition must be opaque.

The next or second step is to rovide a suitable metallic plate having its ace sensitized with a material which is normally soluble in water but can be made insoluble in water by exposure to light. An ordinary zinc or cop per plate having its face so sensitized may be cannot pass through theportions of the master sheet occupied by the opaque impressions, and; hence, the sensitized material on the surfaces of the plate covered by said opaque impressions remains soluble in water. When a negative plate is desired, suitable for printing in relief right side up, the said master sheet must be applied to said plate with its face downward,

The next or fourth step consists in remov-. ing the sensitizing material from the surfaces of said plate which had been covered by the opaque impressions of the master 4 sheet, which can readily be done by washing the plate in water, thereby leaving said surfaces exposed.

Then the next or fifth step consists in covering the said exposed surfaces of said plate with a material which will resist the chemicals used respectively in the sixth and seventh steps. Ordinary printers ink will serve the purpose and it can be readily applied with a suitable inking-roller. Y

Then the next or sixth step consists in removing the sensitized material from the sur faces of said plate which had not been covered by the opaque impressions of the master sheet. which can readily be done by swabbing the plate with a dilute solution of hydrochloric acid.

those surfaces of said plate which had not been :covered by the opaque impressions of the master sheet, thereby leaving the surfaces of said plate which had been covered by the opaque impressions of the. master sheet stand ing high and distinct in relief, and thus affording an unshrunk negative plate available for printing right side up.

For this last, or etching step of the process, I preferably employ the etching machine and process disclosed in U. S. Patent 1,422,977, granted of date January 23rd, 1923, to Edward G. Schwuchow and George F. Johnstone, wherein an alkaline solution is em: ployed as the electrolyte of the bath. I prefer to employ the process disclosed in said U. S. patent as I have found it to be extremely eflicient for the purpose. It completely disposes of the metal etched away and does no injury to the intended printing surfaces. It is possible, however, that Imight employ other suitable forms of electrolytic or acid baths; and, hence, I do. not limit myself to the use of this particular process disclosed in said patent for my etching step.

When the plate comes from the last step of the process above stated, it is obvious that it is in-fiat form and that it could be used in said flat form on some kinds of printing presses; but, for newspaper work, said plate would be curved into half cylinder form, by

the suitableapplication of pressure thereto, and then be mated by another similar plate for the formation of a complete cylinder adapted to be applied and used on the cylinders of the ordinary newspaper printing press, in the same way as the half cylinder plates cast in the usual way from matrix molds. Of course, it will be understood that the plate as it comes from the last step of the above named process will also have to be trimmed, for gettingtheneeded bevelled edges and so forth. Special attention is called to the fact that, inasmuch as all the steps incidental to stereotyping'have been elimin-- ated, my plate and type are unshrunk. The

type therefore corresponds precisely to the composition in all respects including face dimensions.

In the foregoing statement, the word" composition has been used andis herein afterused in the claims, in a broad sense to cover and include nbt only reading mat-' ter, but impressions made from 'cuts, halftones, or electro-plates, for use in association with the reading matter or independently of the reading matter. As typewriting machines are now made, however, so far as I know, I cannot getdirectly therefrom a master sheet for out impressions. Hence, I get such a master sheet from a wood cut, a half-tone or an;electro-plate made in the writer. When the cut master sheet has thus been obtained, it can be associated with the reading master sheet, throughout all the steps of the process above stated, and the final result will be a plate adapted to print the reading matter and the cut matter in association with each other. For example, a single sheet of bond paper of the proper width may be used to receive both the reading impressions and .the cut matter impressions, side by side, in separate columns, or with the cutmatter interposed between paragraphs of the reading matter of the same columns. Ordinarily this master sheet suitable for the double purpose above named would be most conveniently secured by applying the wood cuts, halftones or electro-plates to the sheet of bond paper first, at the portionsthereof desired, and then writing in on said sheet the desired reading matter on the typewriting machine.

Of course, it will be understood that the reading composition of the master sheets produced on the ordinary typewriting machine would not, of necessity, be perfectly justified. A rough justification could be secured by an advance alarm, on the typewriting machine, which would call the operators attention, at the proper time, to the remaining line space available, so he could spread or crowd the last words of the line of the composition. If, however, perfect justification should be desirable, it could be secured, by making the original composition of the reading matter on a typewriting machine having a line-space counter, which would show the shortage or excess of space needing distribution to get justification, and, then, making a second copy from this original measured copy, on the typewriting machine, in which second copy the space would be so distributed between the words of the line as required to secure justification.

It will be understood that some of the details of my process abovedescribed can be changed or varied without departing from the spirit of the invention herein disclosed and pointed out in the claims. For example, while the specific meansspecified for carrying into effect the fourth, fifth, sixth, and seventh steps of my process are the bestv known to. me' for the purpose, it is possible that other s ecifically different means might be employed:

It is obvious that the second, third, fourth, fifth and sixth steps above specified, taken collectively, constitute a means of transferring the composition from the. translucent master sheet to the metallic printing plate.

What is claimed is:

1. The process of producing printing plates having type in high relief, which process includes the following steps, to-wit: (a) producing a master sheet having typewritten thereon the desired composition in opaque printed and counterprinted impressions, the remaining portions of said sheet being translucent; (b) transferring the composition of the master sheet to a metallic printing plate; (0) etching off from the face of said metallic plate all the face surfaces thereof not corresponding to said composition of the master sheet.

2. The process of producing printing plates having type in high relief, which process includes the following steps, to-Wit: (a) producing a translucent master sheet containing the desired composition in typewritten opaque printed and counterprinted impressions; (2')) providing a metallic plate having its face sensitized with a material which is normally soluble in water but which can be rendered insoluble in water by exposure to light; (0) applying said master sheet face downward to the face of said metallic plate and subjecting the same to a strong light; (03) washing said plate with water to remove the sensitizing material from the surfaces of the said plate which had been covered by said opaque impressions of the master sheet, thereby leaving said surfaces exposed; (e) then covering said exposed surfaces with printers ink; then swabbing said plate with a dilute solution of hydrochloric acid to remove the sensitizing material from the surfaces of said plate which had not been covered by the opaque impressions of the master sheet; and (g) subjecting said plate to the etching action of an electrolytic bath for etching off those surfaces of said plate which had not been covered by the opaque impressions of said master sheet, thereby leaving the surfaces of said plate which had been covered by the opaque impressions of said master sheet standing high and distinct, in relief, and thus affording a negative printing plate available for printing right side up.

3. As a step in a process for producing printing plates having type in high relief, the production of a translucent master sheet containing the desired composition typewritten in opaque printed and counterprinted impressions, reading right side up on the face of the sheet and reversed on the back of the sheet.

4. The process of producing printing plates having type in high relief, which process includes the following steps, to-wit :(a) producing a translucent master sheet containing the desired composition in typewritten opaque printed and counter-printed impressions; (6) providing a metallic plate having its face sensitized with a material which is normally soluble in water but which can be rendered insoluble in water by exposure to light, (a) applying said master sheet, face downward, to the sensitized face of said metallic plate and subjecting the same to a strong light; ((2) removing the sensitizing material from the surfaces of said plate which had been covered by the opaque impressions of said master sheet leaving said surfaces exposed; (6) covering said exposed surfaces with a material which will resist the next two steps of subsequent treatment; (7) removing the sensitizing material from the surfaces of said plate which had not been covered by the opaque impressions of said master sheet; (g) etching off from said plate all the face surfaces thereof not corresponding to said composition of said master sheet.

5. The. process of producing printing plates having type in high relief, which process includes the following steps, to-wit: (a) producing a translucent master sheet containing the desired composition in typewritten opaque impressions; (6) providing a metallic plate having its face sensitized with a material which is normally soluble in a liquid but which can be rendered insoluble in said liquid by exposure to light; (0) applying said master sheet, face downward, to the sensitized face of said metallic plate and subjecting the same to a strong light; (65) removing the sensitizing material from the surfaces of said plate'which had been covered by the opaque impressions of said master sheet, leaving said surfaces exposed; (e) covering said exposed surfaces with a material which will resist the next two steps of subsequent treatment; (f) removing the sensitizing material from the surfaces of said plate which had not been covered by the opaque impressions of said master sheet; (g) etching off fromsaid plate all the face surfaces thereof not corresponding to said composition of said master sheet.

6. The process of producing printing plates having type in high relief, which process includes the following steps, to wit (a) producing a translucent master sheet having the desired composition thereon in typewritten opaque'impressions, leaving the remaining portions of said sheet translucent; (b) transferring the composition of the master sheet to a metallic printing plate; (0) etching off from the face of said metallic printing plate all the face surfaces thereof not corresponding to said composition of said