US1578736A - Blanket for printing presses, process for forming the same, and process of printing employing same - Google Patents

Description

March 30 T926. I 1,578,736 R. JOHN BLANKET FoR PRINTING P SES, PROCESS FOR, BRING THE SAME, AND PROCESS PRINTING EMPLOYI SAME Filed Jan. 26. 1925 2 Sheets-Sheet 1 March 30 1926. 1,578,736

I R. JOHN BLANKET FOR PRINTING PRESSES, PROCESS FOR FORMING THE SAME, AND PROCESS OF PRINTING EMPLOYING SAME Filed Jan. 1925 2 Sheets-Sheet 2 I awuemtoz Patented Mar. ,30,

U ITED STAT Es, PATENT OFFICE.

301mm :roinifor BLANKET 'FOR PRINTING new YORK), N. Y.

rnnssns, rnocnss FOR ronmme Tun SAME, AND rnocnss or PRINTING. EMPLo InG SAME.

application fi led J'anuary 26, 1925. Serial No. 4,641

I! '0 all whom it may 0021mm:

. Be it known that I, ROBERT J 0111?, a citizen of the United States, a resident vof'New York, in the county of New York and State of New York, have invented ,a certain new and useful. Blanket for Printing Presses, Processes for Forming the Same,- and Processes of Printing Employingsame,

of which the following is a specification.

My invention relates to blankets for printing presses of all kinds,.and particularly to blankets such asare-iused on the well-known 'ofiset press, and has for its objects, among others, theimprovement of the printing produced by such blankets and beneficial results are attained. To such.

ends, my invention consists in blankets for printing presses and the process of making said blankets, means for fastening said blankets upon a press, and the process of printing hereinafter specified.

In the accompanying drawings,

Fig.1 is a plan view of a blanket embodying my invention, 'a portion of said blanket being skived oflf or shaved to. clearly show the layers of which itis composed;

Fig. 2 is an edge view of Fig. 1;

Fig. 3 is a view of a blanket embodying my invention and having clamps at its ends by which it may be fastened to the press;

Figures land 5 are cross-sectional views, respectively, showing. the portions of a press cylinder by which the clamps at the ends of the blanket in Fig. 3 are secured to the cylinder, -and the blanket-drawn about the cylinder to the desired easy firmness;

Fig. 6 is an elevation view showing the .plate, blanket, and impression cylinders of 1 an offset press, and the gearing for driving them- Fig. 7 is an end view-of Fig. 6.

My invention is capable of embodiment in many different forms, and,' while I have chosen for the purpose of illustration the V best embodiment thereof known to "me, such 55 embodiment is to be regarded only as'typical' and my invention is not to be confined thereto. e

.By way-of explanation, Imay state that,

in the present-practice of printing, the blan- I ket, which may conslst of rubber or other compressible material, ,is stretched tautly around'the cylinder, orover the platen to which it is fastened, one of th efifunctions of such blanket being toequal ize inequali 65. ties between the printing plateandpaper, or otherinequalities which may exist in the cylinders, or platen, or in the press itselfJ I In direct "printing press es, such as those designed toprint directly on paper from type,

half tone engravingsor lithographic stones or plates, the blanket is fastened to the impression cylinder and the paper is fed between it and the plate or type-bearing member. blanket itself comes in contact with the plat or type member, from" which itreceives an ink impression, which ink impression it transfers 'to paper fed between it and. .a separate impression cylinder. In this latter type of press the blanket, in addition to equalizing inequalities, has the function of sion.

- The printersiblankets ,of the prior art have a compressible ink or color-receiving face, but as such face has always been supported upon a stretchable base, the compressibility of the surface material has been reduced by the stretching'of the base in securing it around a cylinder or over a'platen. This has reduced the ability of the blanket to take up the inequalities existing between the press and the plate and the paper, and has necessitatedthe use of. such an amount of pressure =.or squeeze as to cause wear on the plate and-to prevent the use of papers of such composition that their surfaces tend to .pick'orl-ift'when printed under excessive pressure or squeeze.

In the case of'any blanket which is firmly fastened to the press, wear occurs .with

In offset presses, however, the .7

receiving and discharging the ink impres' each" impression between the blanket and that suclra blanket, as made or procured,

the plate, since the blanket, being designed through compressibility to take up inequalities, must be used in a state of compression in order to function. Since a state of compression must therefore exist, a rubbing or frictional effect must take placewithpresents-a total thickness of, say, .065 of an inch and that-to meet the requirements of a given standard press, t'le'total thickness of the finished "blanket should be '.089 of an;

1. A sheet of celluloid or pyroxalin or each impression if either the blanket, or thef other nitrocellulose product having amt'hicle.

ness, say, of approximately .005 of an inch;

plate,- or both, are fastened to a cylinder,

because compression can ,only be effected 411 such a case by increasing the diameter of one or. both cylinders beyond the polnt where, when compressed, the surface of the plate and the blanket would meet in a theoretical line ofcontact. It is thisincreas'e 5 need to impregnate the sheet of fabric 1 with s in diameter which gives rise to sthe rapid wear of plates and in a great measure to so-called gear-streaks in present day offset printing. Moreover, in the case of blankets in offset presses, the reduced degree of compressibility which is. due to the stretching face, reduces the ability torece-ivejand discharge the ink impression completely readily. a

My invention overcomes these-serious objections, and it; comprises a compressible paper-supporting, or inloor COlOr-IQOBIVHIQ face. and means for so securing it to the part of the press which carries it that uts comressibility' shall be free and unrestrained.

n its highest formparticularly on an offset 7 press, it also possesses the quality of having freedom bodily so to adjust itself parallel to the 'surfacet -or part of the press-which carriesthe paper .or ,color orvink, as not to press.

" blanket or the printing plate. I tions may be accomplished in many d1iferent 40 cause wear on the surface'of 'either'the These funcways and :by various constructions.

signed for use on a litho offset? printing My 'nvention, however, is not limited to offset printing presses, but is applicable to all types of presses using a blanket. v As one means of retaining the full compressibility of a blanket while yet securely fastening. it to a press,- ,I may take a rubber facing and secure" it to a non-stretchable back or base, which latter may be secured to the press. As a convenient way of doingthis, I first make or procure a rubber blanket such as is used ,in'the present art. Such a blanket consists of one, or-more layers of fabric, frictionedor impregnated with rubber, on the upper surface of which a rubber coating has been applied and aflixed as by frictioning or impregnating orotherwise forming or attaching thereto. Assuming The example chosen for illustration is de- 2. A-shcet of rolled zinc, alun' inum, iron, copper or other flexible metal, having a thickness of approximately .019 of anlinch.

Laying my "blanket on a smooth surface, with flie -fab ieside uppermost, I next pronitrocelluloseas by'applying to it a solution of pyroxalinajrfi. parts; alcohol,- 47 parts; ether, 4:7 5 parts. I applythis solution by rubbing it into the fabiic with a rag, repeating the operation two or three-times or until is well impregnated with nitrocellulose.

Having permitted the solvent to evapo- [and/ rate,-I next flood the blanket, still fabric side uppermbst, with a suitable quick-acting solvent fornitrocellulose as wood alcohol, irnmediately thereafter bringing the shebt of celluloid 5,. above referred to, into intimate contact with' the saidflfabric side of the blanket (the side oppositeIto-the one having with whichthe fablsic side of the blanket has been flooded tends to dissolve both the sheet of celluloid and the nitrocellulose content of the fabric and that by the rolling or squeegeeing firm adhesion is secured, the flood of solventafi'ecting only the lower side ofthe celluloid sheet and the pressure forcifig it into intimate contact with the fabric. Next, taking the sheet ,6 of rolled metal,

I preferably produce on 'ita fine grain as by I sand blasting or shaking under marbles and flint mud. Having thus grained the metal and washed it free'from loose particles of metal and grit, I next flood itwith a solvent I F it appears that the fabric side of the blanket K ing of the base that supports the 1nk-receiv I ...the rubber on, it) as by rolling or squee'geemg. By 'this'means -I find that .the solventfor nitrocellulose, as wood alcohol, quickly bringing the celluloid side of the rubber blanket, previously described, into-intimate contacttherewith as by rolling or squeegeeing. The result of this operation is to firmly fasten the sheet of nitrocellulose to the metal plate. When the solvent or solvents employed have been evaporated, the resultant article consists of anupper layer of rubber tfirmly fastened to a layer of fabric 2,. which in turn is firmly fastened to a layer of rubber 3 that is fastened to thefab-ric 1, and this latter fabric is secured to the sheet of nitroce-lhilose 5, which in turn is firmly fastened to. a metallic base 6, the thickness of the whole being .089 of an inch as desired. The tenacity-of atfixation is such as to preclude the possibility of any layerbecoming detached from another layer through use as .is clamped, as by the screwsl), My blanket is now ready for mounting upon a press.

.If myblanket is' designed to merely replace one of the tautly stretched blankets on a cylinder press of the present art, it

is firmly secured to the press by the stretching means provided thereon. Used in thlS way, no matter how tightly stretched the metal base may be,the rubber, having been applied without stretching to the base, still retains its full compressibility, or practicallyso, the stretching; qualities of any of the metals described being so slight as to have little or no effect on the compressibility v of the rubber.

As the compressibility of my blanket is not reduced through stretching of the'base" upon which it is supported, my blanket adapts itself to the. inequalities existing between press, plate, and paper with much less pressure than the ordinary blanket requires, and thus the plate issaved from the -wear which comes when an excessive pressure is used. Also, papers can be used of such com osition that their surfaces would tend to ick or lift when used with the excessive pressures ordinarily required,

If, however, it is desiredto' apply' my new blanket to the fullest advantage, I find that thismay be accomplished b securing it comparatively looselyor move, ly on the cylinder. In order to accomplish this result all that is necessary to dois'to leave a slight play in the fastening of the forward endof the blanket and aconsidrable play ,inthe fastening of its rearward'end. By

forward I mean that part of the blanket cylinder which first comes in contact with the plate cylinder. By rearward I mean 'the pdrtionof the blanket cylinder which is last to receivethe impression.

In the illustrated embodlment of in vention, I have shown the blanket as pro- 1 .vided with the usual forward and rearward clamps B and C, respectively, at its ends,

by which it may be. fastened to a ress. These clamps consist of upper and lower strips 7 'which:aresecured together as by screws passing through the strips and the interposed edge of the blanket. In order to illustrate 'the applicationof the blanket to. an offset press, I have-shown in Figures 6 and 7 the blanket cylinder 10 of such a mit such movement.

Having fastened the blanket to the blanket press, which carries the blanketA, the-blanket cylinder being geared at the upper side to the plate cylinder 11, to which the ink is applied, and which transfers its impression to the blanket; At its lower side, the.

blanket cylinder is geared to its impression cylinder 12' between which and the blanket cylinder the paper is fed so ,that' the impression is transferred to the' paper. The

cylinders travel in the direction shown by the arrows.

To fasten theblanketto the blanket cylinder, a' seat ltnis provided for. the lower strip 8 of,theclanip, in which the said strip bears against a shoulder 14, that resists the pull of the blar ike t,- the plate being held down on its seat by a set screw 15. To fasten the rear end of the blanket, a roller 16 is journaled' in a recess in the blanket cylinder 10, and provided-with the usual pawl-and-ratchet' (not shown) for holding it against \any pull of the blanket. The roller 16 is PI'OYIdEd Wlth a seat 17 for the lower strip 8 of the rear clamp C of the blanket, and has a shoulder 18 against which the edge of said strip 8 rests, being forced against it by a screw 19. The metal plate 6- of the blanket terminates a sutficient distance'short of the rear clamp C so as to leave a free portion of the blanket'a that can adapt itself to the curvature of the roller 16, and that will permit easy rearward movement of the blanketby buckling or bending,

of the press tends to move the blanket to. the rearward. The blanketis also free to .move forward, owing to the fact that the portion In of the blanket Fi 4) being radially positioned, may easi y end to percylinder, as? described-,. I next build up. un-

even though very slightly, whenthe action der the plate on the plate cylinder with packing, such as paper, in such a-.manner as to increase, slightly, the diameterof the plate cylinder over that of the blanket cylllO inder. By doing so the plate surface,

printing, is driven at a slightly greater speed than the blanket surface, with the result that the blanket travels forward during the imression period, and him traveling avoids and eliminates the rub or friction characteristic of tightly aflixedblanketspr-inted from in fact, to increase my plate cylinder diameter to such an extent only that the forward travel of the blanket is hardly more than .001'of an inch. Indeed, the slightest travel, even though barely perceptible, is

tightly afiixedplates. The amount of said travel may be almost microscopic. I prefer,

suflicient to eliminate rubbing and consequent wear.

While the" blanket tightening roller 16 is 5 'turned so as to draw the blanket smoothly around the blanket cylinder, the tension thus i put on the blanket is slight as compared with the tension put on the ordinary blanket, and the printing portion of the blanket is entirely protected from stretching by the sheet metal back.

- It will be observed from that after the conclusion of the impression period,the forward edge of my blanket will come up for the succeeding impression ahead of its place by as much as its travel has been. I find, however, that the impact of the 'suc cceding impression at the commencement of. the contact between the plate and the blanket drives the blanket backward to its original starting point; whence it repeats its forward crawl as on the preceding impression; and that the printed sheets are capa- In the prior art use of blankets on offset presses, a great deal of time, usually one or more hours, is consumed in repeatedly taking up the stretch which develops in the blanket as it is used, because each time the blanket stretches, the lengthis increased of the imageor impression which theblanket had previously received from the plate, so

that the next impression on the blanket from the plate will not register with the preceding one but will blur it. The result is that the blanket must .be cleaned of thepreceding impressions, and the process of stretch-- ing, re-inking, printing, and cleaning, must be continuously repeated until the stretch has all been taken out of the blanket. As the printing portion of my blanket is not stretched, and in fact cannot be stretched, no

such adjustment or labor is required, and the cost of time, both of the pres sman and of- .the press itself, is'saved by my invention.

The aforesaid necessity of tightening the blankets of the prior art until all the stretch is taken out of them, compels the use of relatively. thick and strong fabric in the blankets, which introduces unevennesses and irregularities in the surface of the blanket, and makes it more difficult to get a perfectly even impression. My invention, by .eliminating anynecessity for stretching the printing portion of the blanket, enables much thinner and more evenly woven fabric to be 'usedin theblanket, so that a more perfectly smooth printing surface is obtained.

In the case of the offset'press, the high degree of compressibility whichmy blanket retains when-in use presents a stillfurther ,advantage; namely,-it possesses the ability to receive and discharge its ink'impression more completely and more readily than if a tautly stretched, and therefore less compressible, impression receiving and transferring surface on a blanket were-employed.

the foregoing face which attend the use of tautly stretched blankets, is materially reduced or entirely eliminated.

If my blanket is to be used'on the, platen type of'press, the foregoing application is obviously impossible, the blanket having to be firmly aflixed to the platen. In this use the advantage of my invention lies chiefly in the fact of the fullyzcompressible surface, giving a more even impression on the paper, together with less wear on the platen or type and a saving of time in the building up of low spots, commonly known in the printing art as make ready;

pointed out that my new blanket, whether firmly secured to the press or used movably, effects a saving in the wear of the plate.

In the foregoing specification, it has been I point out here that the elimination of frietion which my blanket accomplishes also decreases the wear on the blanket at the same time. I further point out that my blanket, being fully compressible, is less readily injured or cut by particles of wood, paper or other materials which accidentally go through the press; and that. its life is still further increased by the fact that the rubber itself is not stretched, it being true that many blankets employed in the present way areruined by the tearing of rubber or fabric due to continual stretching.

Many modifications of my invention can be made without departing therefrom or from the scope ofthe claims, and my invention is not limited to the particular embodiment. chosen for the purpose of illus tration. w

By the term substantially unperforated is meant such.continuity or substantial uniformityof' the base as will not impairthe uniformity of the face of the blanket in action.

The term means attaching the rubber or other-surface material to the metal backing in the claims is meant to include chemical as well as mechanical means independent of mere adhesion of the rubber or other substance to, the surface of the metal plate.

I claim: i

1. Aprinters blanket co mprising a sub stantially unstretehed compressible face, and is; SIEJStflIltlftllY unperforated'non-stretchable 2. A printers blanket comprising a suba substantially unperforated metallic back or.

base. v

6. A printers blanket comprising a plastic f face, a fibrous body carrying said face, and

a metallic back or base.

7 A printers blanketcomprismg a plus-:-

tie face, afibrous body-carrying said face, a metallic back or base, and a nitrocellulose iastening between said fibrous body and said ase.

8. A printers blanket comprising a plastic face, a fibrous body carrying said face, a metallic back or base, and a nitrocellulose fastening between said .fibrous body and said base, the surface of said metallic base being roughened.

9. A printers blanket comprising a subs'tantially unstretched plastic face and a substantially unperforated non-stretchable back for said face. I

10. A printers blanket comprising a plastic face that is not under tension, and a gaut substantially unperforated back for said ace. Y 11. A printers blanket com rising a taut substantially unperforated bac or base, and

a lastie face whose compressibility is not su stantially reduced by the tautncss of said base. a

12. A printers blanket having a metallic substantially unperforated base, and a substantially unstretched rubber face secured to said base.

13. A printersblanket comprising a nitrocellulose back, and a rubber face.

said back and face, and a metal 14. A printers blanket comprising a nitrocellulose back, anda' rubber face," a sheet of fibrous material being interposed between said back and face.

15. A printers blanket comprising a ni-' trocellulose back, a rubber face, and a metal base secured to saidnitrocellulpse. 6. A printers blanket comprising a nitroce ulose back, a rubber face, a sheetv of fibrous material being interposed between base secured tosaid nitrocellulose.

117. The combination with the member of a 'press for carrying a blanket, of a blanket iaving a substantially unperforated non-' stretchable back that issecured to said member, and a substantially unstretched rubber face secured to said back.

- 18. The combination of a member of a press for carrying a blanket, having a nonstretchable base loosely secured thereto, and a rubber face secured to said base.

19. The combination of a rotary cylinder,

a substantially unperforated non-stretchable base.

20. In a printing press, the combination."

of a rotary cylinder, a non-stretchable base secured to said cylinder, and a rubber face secured to said base,-said basebeing so secured to said cylinder as to permit movement in the direction of travel of said cylinder. A

21. The combination with arotary cylinder of a metallic base so secured" thereto as to permit movement in the direction of travel of the said cylinder, and a rubber face secured to said base.

22. The combination with a rotary cylinder of a metallic baseso secured thereto as to permit movement in the direction of travel of the said cylinder, afibrous body secured to said base, 1 and a rubber face secured to said fibrous body.

23. The combination with a rotary cylinder of a metallic base so secured thereto as to permit movement in the directionof travel of the said cylinder, a body of nitrocellulose secured to said base, a fibrous body secured to said nitrocellulose, and a rubber facing secured to said fibrous body.

24. A printers blanket comprising a substantially unperforated' non-yielding base, and a substantially unstretched compressible face.

25.' A printers blanket comprising a substantially unperforated non-yielding base, and a substantially unstretched rubber face.

, 26. A printers blanket comprising a substantially unstretched compressible face, and substantially unperforated means for so securing it to the part of the'press which carries it'that its compressibility shall be free and unrestrained. A 2.7.- A printers blanket comprising a substantially unstretched compressible face, and substantially unperforatedmeans for so securing it to the partof the press which carries it that its compressibility shall be free and unrestrained, said securing means comprising means permitting the blanket to adjust itself parallel to. the surface or part of the press which carries it.

'28. The process of printing comprising supporting arubber faced blanket on a suitable member, bringing said blanket into contact with an inked surface, and permitting said blanket to move relative to said member during the printing operation.

29. The process of printing comprising bringing a rotatable cylinder having a rubber faced blanket thereon into contact with an inked surface, and permittin the said blanket to move relative to said cylinder during the .printing operation.

30. The process of printing comprising bringing a cylindrical-member having a rubber faced blanket thereon into contact with a cylindrical inked surface, and permitting the" said blanket to move relative to said platen during theprinting operation.

31. The process of printing comprising bringing a rubber blanket on a cylindrical 1 support into contact with a cylindrical inked relative to its support during said operation,

and then bringing said blanket into contact with a sheet of paper to transfer said 1mpression thereto while mounted upon acylindrical support.

33. The process of printing comprisin bringing a rubber blanket on a cyllndrlca support into contact with a cylindrical inked surface, permitting the blanket to move relative' to its support during said operation, and then bringing said blanket into contact with a sheet of paper to transfer said impression thereto and permitting the blanket to move relative to its support while in contactwith said sheet of paper.

34. The process of offset printing comprising printing while maintaining the printing surface of theblanket in unstretched substantially uniformly compressed condition along a line of printing contact.

35. The process of offset printing comprising maintaining the blanket in a taut condition around its cylinder while preventing its printing surface from stretching, said print- .lng surface being maintained in a substantially uniformly compressed condition along a line of printing contact.

36. The process of printing comprising bringing a cylindrical member having a rubber faced blanket thereon into contact with a cylindrical inked surface, moving said cylindrical inked surface at a slightly greater speed than that at which the blanket would move if it moved with the cylinder upon which itis mounted, and permitting said blanket to move relative to said member during the printingoperatiom 37. In a printing press, the combination of a cylinder, a plate mounted thereon, and another [cylinder and a blanket mounted thereon, ",one of said'mounted members being so mounted as to be capable of movement on the surface of its cylinder.

38. In a press, the combination of a member for carrying a plate,- a plate mounted thereon, a member for carrying a blanket, a

I blanket mounted thereon, said blanket having a non-stretchable base, and a rubber face secured to said I base, one of said mounted parts being capable of movement on the surface of the member upon which it is mounted.

39. The combination with the'rotary oylv inder, of an imprinting member having anonstretchable base, said base being so securedupon said cylinder so as to permit travel in. the direction of said cylinder.-

40. The process of printing, comprlslng supporting an imprinting member on a part having a geometrical surface, bringing said imprinting member into'contact with an inkreceiving member that is mounted upon a part having a geometrical surface, and per mitting one of said imprinting members to move relative to its supporting part during the printing operation.

41. The process of printing, comprising supporting an imprinting member on a part havlng a, cylindrical surface, bringing said imprinting member into contact with an inkreceiving member that is mounted u one part having a cylindrical surface, an permitting one of said supported members to move relative to its supporting part during the printing operation.

42. The process of printing, comprising supporting a rubber blanket on a cylindrical part, supporting a plate upon a cylindrical part, bringing said plate and blanket into contact, and permitting one of said supported parts to move relative to its support during said operation, and bringing. said blanket into contact with a sheet of paper to transfer said impression thereto.

43. In a rinting press, the combination of a cylinder having 'a rubber-faced blanket,

so mounted thereon as to be movable in the dlrection of travel of said cylinder, and a cylinder having a part with an inked surface mounted thereon, moving said cylin- I ders at the same angular speed, and the effective radius of the inked surface being slightly greater than the effective radius of the rubber-faced blanket when compressed to effectuate proper printing.

45. A printers blanket comprising "a substantially unstretched compressible. face, a.

metallic back, and means securelyrjattaching said face to said back substantiallythroughout the entire surface of said base.

. 46. A printers blanket comprising a substantially unstretched elastic face, a metallic back, and means securely attaching said face to said back substantially throughout the entire surface of saidbase.

47. A printers blanket comprising a substantially unstretched rubber-like face, a me-- tallic back, and means securely attaching said face to said back substantially throughout the entire surface of said base.

48. A printersvblanket comprising a sub- 5 stantially unstretched rubber face, a metallic back or base, and a nitro-cellulose fastening attaching said face to said base.

49. A printers blanket comprising a sub- January, 1925;

stantially unstretched rubber face, a metal- 1ic back or base, and a nitr0-ce11u1ose"fastening attaching said face to said base substantiallythroughout the entire area of contact. In testimony that I claim the foregoing, I have'hcreunto set my hand this,7th. day of 7 ROBERT JOHN.

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