US2032770A - Planographic printing plate - Google Patents

Description

Patented Mar. 3,A 1936 rmNodnarmo rammd PLATE George S Rowell Cleveland, 0l

Mulfinlh Company, .poration of Delaware y o, or to n, Del., a cor- Appiicatim January as, 1934, semi No. :ossei s claim. w1. 1er-4m 'I his invention relates to a planographic printing plate having a metallic surface and adapted for carrying an ink-receptive image and an inkrepellent on the non-image areas. The pres-ent application is acontinuation in part oi my copending application Serial No. 550,310, died July 13, 1931. One of the objects is to provide such plate with a surface especially suitable for holding viscous ink repellent such as is used in socalled dry lithography.

Another object is to construct the plate so that it shall be suiciently yielding to readily operate in a planographic manner in direct printing so that, if desired, the plate may be employed either in an offset press or a direct press. Other objects 'are cheapness of construction; lightness of weight of the completed plate; exibility to enable it to be readily rolled around the platen of an ordinary typewriting machine to receive an 2Q image, or to be-drawn taut in the press. y

My invention :is hereinafter more fully eirplained in connection with' the drawing, and the essential features are summarized in the claims.

In the drawing,

i Fig. l is an' edge View of my complete plate greatly magnified;

Fig.- 2 is a perspective of the base member thereof; y

Fig. 3 is a diag animatie elevation of an apparatus for spraying molten metal on the base of Fig. 2, after the manner of the well-known Shoop method.

In the drawing, A represents a sheet of abricl which may be paper, felt, a finely woven textile,

or other non-metallic material. B represents a coating of minute, rounded, cohering metallic particles adhering tothe sheet A. An adhering lm of these cohering metallic particles may he readily formed in situ by a spray gunC, as illus- 40 trated in Fig. 3, which is supplied by three' cong duits c', c2 and c3 feeding it with oxygen, acetylene and compressed air, or other means to obtain a discharge of compressed gas together with a high heat. c indicates a wire of metal fed to the spray gun and fused and propelled by it, as set out for instance in Patent No. 1,549,843 of Nicolaus Meurer, issued August 18, 1925.

- Assuming for instance, that the wire 4supplied .to the gun is zinc, which is the preferred metal,

the burning gas will melt the same at the nozzle of the gun and the compressedair win propel it in' the form o'fminute molten particles b which,

on contact with the fabric base A, solidify and adhere thereto, and thusform in situ the coat` ms B on the said base.-

ticles and thus,

It is obvious that some particles will fall on and cohere with other particles previously attached to the base A.' Such superimposition of particles is not objectionable so long as the gramnessr produced thereby is fairly uniform throughout .5 the'area ol the plate. As those skilled in the art well understan the grain o a planographic plate plays an important role in the performance of the plate and it is one of the advantages of the plates oi this invention that the conjoined par- 10 ticles constituting the printing surface provide a better type `o grain than'oan he obtained by grinding `or -sandblasting sheet metal, as is the usual practice.

While the metallized surface of the plates of 15 this invention should be continuous and eiect complete cover e o the oase material, the thinnest portion of the metallized surface need not be thicker than a single particle constituent thereof. The dlerence between the thinnest 20 portions or the metallized surface and the thickest portions thereof is determined'by the superimposition of particles, as above mentioned, and by the character o the desired gra Complete coverage of the surface of the base 25 material by the .metal particles and a substantially uniiorm graininess throughout the area of the plate may be obtained by conventional manipulation of the spray gun, caused to traverse the plate by a reciprocating 30 motion while the latter is progressively moved in a direction normal to that of the path of the guns movement. as apparatus suitable for the purpose is commonly used for metal spray-coating, no further descriphon thereof is deemed neces 35 sary here.

Particles obtained by spraying molten `metal are rounded and may be sometimes dome shaped as schematically illustrated in Fig. l, and are thus better adapted for retaining a chemical ink re- 40 pellent and particularly viscousrepellents than the sharp pyramdal surface made byrmeohanical graining or sand-blasting, as stated. The character of the Yspray is controlled' by the air pressure and temperature developed at the spray 45 gun, and hence, the iineness oi the spray may be varied and controlled as desired, and by ,these means I can vary the size of the individual parin conjunction with the mentioned relative and progressive motion 'of the 50 plate and gun, I can effect complete coverage of t the surface of the base and, as stated, produce the kind o1' graininess best suited for the printing intended.

An advantage of my non-metallic fabric back- 55 printing, and also saves wear on the Journals of the rollers by reducing the pressure required.

I am aware that metal foils have been heretofore backed with paper and used as planographic plates; but such prior plates, not only had to be mechanically grained, but the foils had to be thick enough to stand the graining operation and, in consequence, were devoid of the desirable recoverably-yielding characteristic of the plates of this invention. 'Thick metal foils, even when 'mounted on a non-metallic backing, tend to disadvantageously emboss. It is an advantage of my plate that embossing is substantially avoided.

Because of the very tenuousness of the metallic film, derived from the coherence of the sprayed particles, which constitutes the printing surface of my improved plate, I prefer to employ a backing which is capable of taking the strain, incident to attachment to the form roll and the printing operation, without stretching the metallic facing beyond its elastic limit. Fabric sprayed in a stretched condition is suitable for my purpose, as is also any good grade of heavy rag bond paper. I do not wish to imply a limitation to the mentioned backings, because it will "be obvious to those skilled in the art that other backings may be used without departing from the scope of the invention as defined ln tle appendedv claims.

I claim:

1. A planographic printing plate comprising a.

flexible backing, a metallic facing consisting of a advantages of offset to the backing,

ilexible backing,

. sisting of a plurality 2. A planographic printing plate a flexible backing, a ilexible metallicfacing con. sisting of a plurality of metallic globules adhering and an ink plied directly to the globules.

' 3. yA planographic printing. plate comprising a a metallic facing consisting of a particlesadhering to the backreceptive image applied directly printing plate comprising a plurality of zinc ing, and an ink to the particles.

4. A planographic ilexible backing, a exible metallic facing consist.

ing of a plurality of zinc globules adhering to the backing, and an lnk rectly to the globules. l v

5. A planographic printing plate comprisinga flexible backing anda metallic facing consisting of a plurality of cohering metallic particles adhering to the backing.

6. A planographic printing plaie comprising a flexible backing and a ilexible metallic vfacing 'consisting of a plurality of cohering metallic globules adhering to the backing. f

'7. A planographic printing plate comprising a flexible backing of a plurality of to the backing.

8. A planographic printing plate. comprising a ilexible backingl and a' flexible metallic facing conof cohering zinc globules adhering to the backing.

' GEORGES. ROWELL.

cohering zinc particles adhering receptive image ap-V particleadheringtothe receptive image applied diand a metallic facing consisting

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