US859587A - Surface-printing plate. - Google Patents

Description

' PATENTED JULY @1907.

IMO/859,587.

A. 3. SHERWOOD. SURFACE PRINTING PLATE." APPLIUATION )PILED MAY 21, 1906.

Ina/671507 flieacarbderfi Sierwaoai,

ALEXANDERB. SHE nwoon, OF.OI-IICAGO, IILLINe s SURFACE-PRINTING PLATE 1 Specification of Letters Patent.

Patented. July 9,1907.

Application filed NESL 21,1906. Seri el No. 317,949.

To all whom it may concern:

Be it known that I, ALEX NDER B. Suemvood, a citizen of the United States residing at (,hieago, in the county of Cook and State of Illinois, have invented a new and useful Improvement in Surl'aie-Printing Plates, of which the following, is a specification.

My invention relates to improvement in the construetiou of snrfaceprinting plates for rotary or reciprocating printing presses and also in unimproved method of printing thereby rendered possible.

Surlaceprint.ing is usually perl'rnnied in a rotary press and it has been most common hitherto to provide a pres having two 'eylinders, one, the printing-eylin der, carrying the stu'l'ace-printing plate and the other, or i1npression-eylinder, carrying a rubber blanket. The plate employed in such presses, hitherto provided, is usually zine or aluminium oi-a thickness, as a rule not less than .026 of mi inch mounted upon the printingwylinder to rest [irmlyagainst the metal lace thereof. The sheet to be printed is fed between the printing-cylinder and the iuipression-cylindor, the.

necessary close contact being eileeted in a measure by the resilient quality of the rubber blanket Much difl'ieulty has been experienced in operating presses ot this type, provided with surfaewprinting plates, such as described, to obtain the. density and sharpness of out line of impressions so desirable in high, class work ;and

especially so when the paper to be printed was of a hard quality, such as bond or ledger paper. All paper has a more or less uneven surface and in the case, more'espe- 'cially, of the hard papers described, it is dillieult to produce impressions with desired uniform density of color and sharpness of outline.

An improvement over the well-known printing press described has been produeed by constructing a press I with three cylinders, namely a plate-cylinder on which the sheet of paper, .or the like, passing between it and the llilpltfifiit)WCYliXKlOl. In thus printing trom rubbera better rontaet than formerly is'had, with the sheet of paper or the like to be printed, and-a sharper outline of the printed design thus obtained, a rule; but this iseffected at a sacrifice in density of color: Furthermore in the use. of the three cylinder press some dithculty has been experienced in maintaining the proper register, owing to the tendeney oi the gearsto wean however slightly, and the necessary lost motion be tween rotating parts which could not be avoided. I A further disadvantage attending: the use of the rubber printing sheet is its tendency to wear and the et'l'i-et Referring to I the drawings thereon of oils, turpentine and the ink itself as well'as' atmospheric influences, all oi \vhieh tend to unlit the rubber for more than limited use. V

My object is to provide a eonstruc tion oi' surlaeeprinting plate by the use of which the objections to the other printing ine-ans 'hereinbeiore mentioned are oi 'ereome; ivherebythe"printing inay he as dense as desired. and sub' (:t to regrulation, and'shzir mess of outline may be maintained throughout the run.

It is lso my object to provide a"eonstruetion of surface-printing means ivhich will be more economical in the mumof cost and maintenance than those hitherto employed.-

In carrying out my invention I'employ as the surand highly ness) which laee printing means a sheet oi' very thi. flexible metal (si .004 oi anineh in ,t

will undnlate ireely under uneven pressure against,

its surface, the said sheet being imposed upon a backing of relatively sol't, cushioning, resilient material, such as rubber anvas and rubber l'abriq or the lik The thin metal sheetfivitli its backing. described "is mounted upon plate-cylinder, which may be andprel'erably is the printlug-cylinder, and the impres-' sion-eylinder is also by'preference provided with a eushioning' surfai-t preferably of rubber or tliellike.

1n the operation of the press a new and improved method of printing is produced (fons i ing; in the im pressing of a thin, hard, highly flexible and resilient sheet-metal surface-printingIplate'yi'eldiiigly and undulatorily against the ,yieldingly supported sin-lace to be pr nted, thereby effecting sharpness of outline and quality, or density, of color ivhich so far as lam I aware eanbe obtained in noother way. f

, igure 1 show sa surfaceprinting, plate-carrying, printing eylinder and. an impression-eylini as .l preier to construct .them in earryingout inyi v itio i, the cylinders being broken away in places to expose details of eonstruetion \vhieh would otherwi ot; hidden; and Fig. 2, ,a broken pen spectivo View ofthepreferred form of clumping means for the thin metal sheet. i v i The printingwylinder 3 has the usual nietal i'aee and is reeessed as shown 321. Near the sidesoi the recess 4 are tightening:rollers slitt ai longitiulihally to receive op ipsile ends ol' an'ushion, preferably a rubber blanket (i, -irhiel1 is caught at its edgcs andll'astened. as by the seren's sl oirn in the slits oi' theroller s, and tightened or stretched over the surl'aee of the ,eylinder by ilugturnipg of therollersein the, coninion manner. lixteiidi ng parallel,n'iththe roller 111d also mounted in suitable hearings in the recess 4, aleroek-shalts 7,

earrying arms 5 having bifureated heads 9.

it) is a sheet of very thin metal of uniform thickness throughout and of flexible, resilient quality: It may be zinc or aluminium, for example, or, and preferably, eoppen Any suitable metal having the desired qualities may be employed. The heads 9, disposed as shown in the figure, form clamps to receive the opposite ends of the sheet 10,'the clamping being performed by tightening the screws 11 shown in Fig. 2. The arms 8 with their heads 9 are in pairs along the respective shafts 7, the pairs being connected by means of turnsmoothly over the backing 6. On the impressioncylinder ]3 I'sliow a cushioning sheet 14, preferably of rubber, or the like, to present a yielding and resilient surface. The sheet 14 is mounted at its end in tightening rollers 15 cpnstructed like the rollers 5.

In operation the sheets of paper, or the like, to be printedare fed'in the direction of the arrow, and to facilitate the feeding'l prefer to mount the cylinders at an angle to the vertical plane, with reference to each other, as indicated. The sheet 10 carries upon its s'ur-' face any suitable, appliedink-design, which is imposed thereon inthe usual'way to' print in the manner well understood. It has not been thought necessary to illustrate theinking rollers, which may be of any usualor suitable construction. I In printing, the sheet of paper, or the like, is squeezed with desired pressure between the cylinders and as both the printing andimpression surfaces are of a yielding-resilient, undulatory character the very closest contact is brought about between the printing surface and the surface to be printed. Slight variations inthe thickness of the paper, or the like, will be compensated for by the hndulating action of the .two resilient surfaces between which it is compressed. Of course the cylinders in practice would be' adjusted with reference to each other in the usual way to conform properly to the thickness of material being printed.

As the design is printed directly/from a metal sur face its sharpness of outline and .properuniformity may be maintained without difficulty, and by rendering this metallic surface yielding'and'undulatory as described, all the advantages of perfect surface contact in printing is obtained; and the use of a. resilient surface, or surface-covering, 14 on the impression-cylinder enhances this' effect withthe result that more perfect I and uniform surface-printed impressions are produced than by any other means of which I am aware.

Owing to the; resilient character of the printing surface, and the readiness with which it un'dulates under uneven pressure, the inking rollers will contact therewith, even under comparatively slight pressure, with greater uniformity throughout than is the case. wherea stiff or unyielding surface printing plate is employed.

slight pressure is necessary between the moving parts,

as the yielding faces of the cylinders readily conform to each other. The fact that less pressure between the cylinders is necessary is a great advantage, particularly in color work where undue pressure tends to spread the ink and stretch the sheet being printed, thus interfering with exact register. It will be understood, of course, that the press provided with my im-' provements maybe employed for printing upon sheets of metal or other material besides paper.

My improvements tend not onlytoenhance the results in surface-printing, but also to eheapen the cost materially. The sheet 10 being very thin is naturally less expensive than the heavier sheets, or surfacecally no wear upon the backing, which will therefore last indefinitely. As there is little frietionbetween,

printing platesfhitherto employed. There xispractithe cylinders, the wear upon the surfaces of the printing-plate and impression-cylinder is reduced to a minimum. The sheet 10, forming the surface portion of the printing-plate, may be an integral part of the backing 6. 'For example a sheet 6, of rubber or the like,

may be plated withmetal 'which plating would be the 2. The combination in -u printing press of a printing.

cylinder, 11 surface-printing sheet of highly flexible and resilient thin sheet metal, and a backing therefor of relatively soft cushioning material and means engaging the edges of the printing sheet and its backing to secure them upon the printing cylinder, and an impression surface hav-' ing a relatively soft and resilient surface portion, for the purpose set forth. a

Iii-The combination in sprinting press: of a printing cylinder,a surfuce-printlhg sheet of highly flexible and resilient thin sheet metal, and a backing therefor of sheet ruhber, and means engaging the edges of said metal ,sheet and backing .to secure them'upon the printing cyll'ndeiand an impression cyiinder co-operating with the printing cylinder and having a rubber circumferential l. The'combination in a printing press, of a printing cylinder, a surface-printing sheet, of highly flexible and resilient thin, sheet' netul, a backing therefor of relatively surface portion, for the purpose set forth.

soft cushioning material, means for securing said print-- lug sheet undflbacklngat their edges to the surface of the printing cylinder and an impression surface having a relatlveiysoft and resilient su iface adapted to co-operat'e with said printingsurfnce.

- 5. The combination in a. prlntingbpress, of imprinting cylinder, :1 surface-printing sheet or highly flexible and resilient thin sheet metal and bucking therefor of reintlvely soft cushioning material, means for securing said printing sheet and backing at their edges tothe surface of the printing cylinder and an impression surface havingv

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