US1215493A - Process for producing printing-plates. - Google Patents

Description

UNITED sanrn PA cram GEORGE E. CORNWALL, OF RYE, NEW YORK, ASSIGNOB, BY MESNE ASSIGNMENTS, TO

JAMES G. COFFIN, TRUSTEE.

PROCESS FOR PRODUCING PRINTING-PLATES.

No Drawing.

Specification of Letters Patent.

Application filed March 20, 1905, Serial No. 251,095. Renewed July 6, 1916. Serial No.

To all whom it may concern:

Be it known that I, GEORGE E. CORNWALL,

a citizen of the United States, residing at Rye, in the county of Westchestenand State of New York, have invented a new and useful Process for Producing Printing-Plates, of which the following is a specification.

The invention relates to the production of planographic printing plates. An object of the invention is to produce a printing plate of great durability, which is capable of yielding work of a high quality and at great speed, which is easily and inexpensively made, and to provide a method for producing such a plate. These and other objects of the invention will more fully appear from the following description.

The invention consists in the novel steps, processes, and improvements herein shown and described.

It has heretofore been well-known that particular substances possessing certain natural properties, or being of a particular chemical composition, are adapted to form the elements of a planographic printing surface. Planographic printing surfaces have generally consisted of two substances possessing natural properties, respectively, whereb one substance will act as the ink-taking eliement and the other substance as the inkrejectin element. In the case of certain materia s, chemical changes are induced in these elements whereby the tendency to take or reject ink due to natural properties is enhanced, or this property or quality is created. It is also known in the art that single substances, of a colloidal or gelatinous nature, are adapted to act as both the ink-rejecting and ink-taking elements of a planographic printing surface by reason of changes wrought in their chemical composibut without changin the chemical constitutron or identity of t e material, and being independent of the normal properties or chemical constitution of the substance or material. There are various materials or substances which may be made, by means of changes effected in their physical state or condition, by means of the process included in this invention, to act as both the ink-taking and ink-rejecting elements of a planographic surface. Among such materials are some of the metals, and glass.

The process included in the invention has in view that the portions of the material which are to form the ink-rejecting parts of the surface shall be put in such physical state or condition that they may be capable of acting as such ink-rejecting part, and that the portions of the material which are to form the ink-taking parts shall be put in such physical state or condition that they may be capable of acting as such ink-taking part, and that the said ink-rejecting and ink-taking parts be disposed with respect to each other so as to form or define the design or printing effect which it is desired to produce.

Various materials are capable of being treated by the process included in this invention so as to produce printing plates of the character hereinbefore set forth. Among such materials are certain metals, and glass. The physical state or condition of such materials may be changed in a variety of ways, all of said ways being included within the scope of this invention.

A suitable material, such as one of those above indicated, may be preparedto act as such a planographic printing surface by causing one portion thereof to assume an open, noncompacted or porous structure so that it may be adapted to reject ink by means of capability to hold moisture, or to hold a moisture-attracting, or other ink-rejecting, medium or material. I Other portions of the said material may be treated in such manner as to render its surface dense, polished, compacted, indurated, or otherwiseadaptingit to act efficiently as the ink-taking part of the planographic printing surface. Placin this part of the material in one of the physical states or conditions mentioned will effect this result, for the reason that materials in such physical state or condition are adapted to resist the action of moisture-applying means and will therefore take ink readily, as printing inks will adhere to dry surfaces.

- As illustrating one manner of. putting the process into practice, a suitable material may be taken, such as the metal zinc. The surface of the metal may be rendered dense or indurate by rolling or polishing, or in other suitable manner, and the design may then.v be, laid on in any suitable resistant material, such as' a sensitive asphalt, which is then exposed to light so as to harden it. The surface of the plate outside the design may then be treated so as to bring it into physical state or condition suitable for the ink-rejecting part of the printing surface. This may be done, as before indicated, by renderingthe surface non-compacted or of otherwise open structure, as by graining either mechanically or otherwise, the resist meanwhile serving to protect the design, and to preserve it in its desired physical state'or condition. A material dissolved in an aqueous solvefit, such as a gum, may now be applied in solution to the surface and dried. A non-aqueous solvent, such as benzol, or chloroform, may be used to dissolve the resist from the [design part. A plate will thus be produced having a planographic printing surface consisting of a single material, but having a part of its surface in such physical state or condition as to reject ink and having another part of its surface in such physical state or condition as to take ink.

As illustrating another manner of putting into practice the process included in this invention, the entire surface of the plate may be placed in condition to reject ink, as by A, placing it in a dense or compacted state or condition, which may be done by giving the surface a high polish. The design may be laid thereon in sensitive asphalt, or other proper resistant material, in a manner known to the art, and the remainder of the surface may then be slightly roughed or etched with an etching agent, such as an acid solution. That'part of the surface is then in condition to readily take and hold an electrolytic deposit. The plate is placed in 50.

an electrolytic bath and receives a deposit of the same metal on its surface except where protected by the resist covering the part which is to constitute the design. The resist may then be removed.

The surface of the plate produced by the process as thus carried out will consist of a single material in two physical states or conditions, one art being ink-rejecting and the other ink-ta ing. In this case this result is realized by the design portion of-the plate having been rendered of a comparatively dense or compacted structure and the nondesign part of a comparatively open or noncompacted structure.

The invention, in its broader aspects, is

not limited to the particular manner or means for carrying out the-process hereln described, nor to any particular manner or means, as changes may be made without departing from the main principles of the invention and without sacrificing its chief advantages.

What I do claim as my invention and desire 'to secure by Letters Patent, is: 1. The process of producing a metal pla- -nographic printing plate having a printing tory to placing ink or like design defining material thereon, as will put it in such physical state or condition as to vmake it ink taking to form the design element of the printing surface.

2. The process of producing an all metal planographic printing plate which comprises compacting the metal of that portion of the surface of the plate which is to constitute the design and, rior and preparatory to placing ink or like design defining material thereon, rendering non-compact the non-design or ink-rejecting portions of said surface.

3. The process of producing a planegraphic printing plate having a printing surface consisting of a single metal which comprises indurating a part of the surface of said metal to adapt it as the ink-taking element of the plate and treating the remainder of said surface so that it may have an open or non-compacted structure to adapt it to act as the ink-rejecting element of the late.

4. T e process of producing a lanographic printing plate having a printing surface consisting of a single material which consistsin polishing a part of the surface of said material which is to constitute the ink-taking'element of the plate and graining the remainder of the surface so that it may form the non-printing part of the plate.

5. The process of producing a plumgraphic printing plate having a printing surface consisting of a single metal which consists in polishing a part-of the surface of said metal which is to constitute the inktaking element of the plate and graining or ink taking element of the printing surface and rendering minutely cavitated the surface portion thereof which is to constitute the non-design portion.

7. The process of producing a metal planographic printing plate which comprises rendering dense and smooth the metal of the plate in that portion of the surface which is to constitutethe design or inktaking elementof the printing surface and rendering minutely cavitated the metal of the plate in that portion of the surface which is to constitute the non-design or inkrejecting portion of the surface of the plate.

8. The process of producing a planographic printing plate which consists in providing a plate one of whose surfaces is ink-taking, smooth and consists of a single metal, arranging a design of ink-taking material on a portion of the said surface and in the plane of the other portions of the said surface, covering the said design with a substance capable of resisting the action of a graining agency, graining the non-design or said other portions of the said surface to render themv ink-rejecting and water-holding and then removing the substance which covers the design.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

' GEORGE R. CORNWALL.