US1227557A - Make-ready of impression-cylinders of printing-presses. - Google Patents

Description

A. W. COCHRAN III F. M. YOUNGS. MAKE READY DF IMPRESSION CYLINDERS 0F PRINTING PRESSES.

APPLICATION FILED AUG-7,1916.

Patented May 22, 1917.

a city of- Portland, county of Multnomah, State of Oregon, have invented a certain' sn'e Rana one.

nnnnnr w. ocean .ann rnnn nt. YOUNGS, or ron'rnnnn, onneon:

nr-nnanr .or narnnssron-crnmnnns or rnrnrrne-rnnssns.

Specification of Letters Patent.

neeaaaa To all whom it may concern."

Be it known that we, ALBERT W. CoonRAN and FRED M. YoUNos, citizens of the United States, and residents, respectively, of the new and useful Improvement in Make Ready of Impression-Cylinders of Printin Presses, of which the following is a specii ication. I

@ur invention particularly relates to newspaper presses and has for its object the providing of impression cylinders with a make ready or circumferential covering which will produce clear-cut imprints, and whichyfurthermore, iseconomical with regard to its cost, application and length of service.

In order to understand the nature of our invention, it is convenient to state, in the first place the undesirable conditions now met with 1n the art, and contrasting therewith the beneficial results obtained from 7 our improvement. In so doing reference will be had to the in which:

Figure 1 shows-diagrammatically an enlargedperspective elevation of the capital letter T in block type; Fig. 2 shows a cross-section ofsuch type, and apartial, longitudinal section of the accompanying drawings,

I impression cylinder provided with an imcyhnder perfect make ready 5 and this figure repre-' sents in'exaggerated form the undesirable printing action likely to result;

Fig. 2* shows diagrammatically the blurred imprint produced by saidimproper condition;

Fig. 3 shows adiagrammatic, partial perspective, partly in section, of an impression having. ourimproved make ready or circumferential covering applied thereto; Fig. t shows a manner of preparing our improved make ready for being fastened on the circumference of thecylinder;

Fig. 5 is an-exaggerated cross-section of oursaid make ready Fig. 6 illustrates diagrammatically, and comparatively to-Fig. 2, the improved re sults in the printing operation obtained by our invention; and

Fig 6 represents a clear-cut iniprint, to"

purpose of our inven- Patented May 22, 1911?. 1 Application filed August 7, 1916. Serial No. 113,676.

sioncylinder must be made ready, and to I this end is circumferentially covered with a carries the stereotype .plate.

The two cylinders must have the same relative Working diameter, in order to run at the same speed, for if they run at unequal speed there would-be a tendency to drag the plate, relatively, over the paper supported by the impression cylinder, and so blur the imprint.

The make ready of the impression cylinder, as'heretofore practised, consisted in covering its circumference with a rubber blanket and'then covering the latter with a felt blanket. The difliculty experienced in such make ready is, the felt blanket permits considerable. sinking in, which must be guessed at, because allowance must be made in adjusting the working diameters of the two cylinders; referring to those diameters which the cylinders respectively assume when the one carries the plate and the other the make ready. The necessity for figuring outapproximately the allowance to be made for-the sinking in during the printing operation is shown, for instance, in newspaper work, where half tones are printed alongside of type. In such case, since the half tones require a heavier impression than the type, they must frequently be sacrificed in order to have a sufliciently light impression which will not paper printed to be pressed against the side faces of the type, thus causing a distorted,

instead of atrue, clear-cut impression.

This undesirable efi'ect may be graphically illustrated by the aid of the diagrammatic Figs. 1, 2, 2? in the accompanying drawings.

Fig. 1 represents a diagrammatic perspective of a type printing the capital letter T. Fig. 2 is a cross-section illustrating a likely undesirable contact of the sheet imprinted with the side faces of the type, due

we I

trated in Fig. 2*,

the character, as illustrated byto the fact that the make ready permits.

the type to sink too deeply into the surface.

. lln other words, under such conditions, the

speed so resulting would have a tendency to pull the paper so hard as to cause it to paper would have tearg and in that case the torn end of the a tendency to wind up on the impression cylinder so tightly as to kill the resiliency of the felt'blanket and render it unfit for further service, because felt possesses only a limited come back property, for its texture is susceptible of being matted down by sustalned pressure; and in consequence of this inherent weak- I ness in felt the blanket usually employed 1 as a part of the make ready loses its come back even in ordinary work in a comparatively short period. Then there is this further disadvantage in the old style of make ready The felt blanket will stretch, and has to be retightened from time to time, and in this way it is finally stretched so thin as to lose its resiliency. At the same time the diameter of the impression cylinder would be varied to such extend as to require it to be built up anew, in order to make its working diameter approximately equal to that of the printing cylinder, and prevent the consequences due to the working diameters of the two cylinders being unequal.

In seeking a remedy for said undesirable eflects we have discovered an' improved make ready for the lmpresslon cylinder,

which provides the latter with a suitable covering sutficiently resilient to allow for the irregularities in the printing faces of'the stereotype plate, at the same time resisting the forming of any hollows into which the printing character maysink, and cause the undesirable consequences illustrated by Figs 2, 2

The make ready invented by us consists of a base made of textile fabric coated with a thin layer of composition 1, consisting of ground cork and oxidized linseed oil. In making up this composition the linseed oil is dried and ground up, then the two articles are mixed, and then the mass is heated, and

' v while still hot the composition is spread 1n the form of a layer on the textile base, and then rolled to the required uniform thickness, approximately .145 of an inch. This is the usual thickness of a built-up make Figs. 6, 6.

manner ready, and it is to be noted that our make ready is to be used by itself, without any additional strips, felt blanket or rubber sheet, as heretofore required. Both and either of which possesses undesirable properties from which we get away by our invention, as'mentioned. In other words, our

new result can only be obtained by printing directly upon the surface of our make ready, the lntervening draw sheet not belng considered as it merely serves to keep our make ready in place on the cylinder, and

9 provided for that purpose on the channel z" of the impression cylinder.

lin Fig. 3, 2' represents the impression cylinder, j the make ready orcovering as a whole. The impression cylinder is provided with the usual reels m, m, on the former of which one end of the draw sheet n is fastened, the other end being fastened on the reel m. The draw-sheet encircling the make ready is covered, the latter being flexed around the cylinder, and by then winding up the reels m, m, or one thereof, the draw-sheet is drawn tautly, and in so doing firmly holds the make ready on the circumferential surface of the impression cylinder.

Ground cork is especially adapted for making our make ready since it has .the required resiliency for yielding to irregularities in the printing faces, and a make ready made as herein described has, furthermore, the stable come back required to maintain the impression surface in a uniform plane and also to resist the forming of cavities therein, for while resilient it is not so yielding as to permit crushing in, as does felt or rubber. Our improved make ready is particularly adapted for stereotype plates, which cannot be cast accurately, but

present a more or less irregular printing face.

The efiect obtained by my improved make. ready is graphically illustrated in Assuming the capital letter T is being printed, the make ready y will yield suficiently to allow for irregularities and produce a clear-cut imprint, such as is illustrated by Fig. 6 in comparison with Fig. 2; for the type cannot sink into the surface of the make ready to such extent as to cause the portions y" of the make ready to bring the sheet imprinted into contact with the vertical edges 6', and thus prevents blurs as e, e in Fig. 2.

Our invention also produces a cheaper make ready, for the felt blanket must be made throughout of a good quality of wool, in order that it ,will have the necessary resiliency or come-back. And ourinvention has the further advantage that it requires less adjustment. In practice, with the old style of make ready, after the press had been run for a time it necessitated readjustment of the make ready. On the other hand, when our make ready is used, and has been adjusted after a days run, it will stand. up indefinitely without further adjustment. In trials heretofore made by us, our improved make ready has been used for sixmillion impressions and is still in good condition, While the old style of make ready, using a felt blanket, would be about used up in such work, and require renewal.

Our make ready is to be used in place of both the rubber blanket and the felt blanket now in use.

We claim:

1. A make ready for impression cylinders consisting ofa strip of substantial thickness made wholly of comminuted material having resilient properties similar to cork, held in mass by a suitable binding agent, and including other material adapted to "hold the mass against pulling apart, said make ready being made of a thickness adapted for imprinting directly thereon.

2. A make ready for impression cylinders consisting of a strip of substantial thickness made Wholly of comminuted material having resilient properties similar to cork, held in mass by a suitable binding agent, and mounted on a base strip adapted i to hold themass against pulling apart, said make ready beingmade of a thickness adapted for imprinting directly thereon.

3. A make ready for impression cylin- ,ders consisting of a strip of substantial thickness made wholly of comminuted cork held in, mass by a suitable binding agent, and mounted on a base strip adapted tohold the mass against pulling apart, said make ready being made of a thickness for imprinting directly thereon.

4:. The combination with an impression cylinder, of a make ready consisting of a circumferential coating of substantial thickness made wholly of comminuted cork and strip adapted to hold the mass against pull-,

ing apart, and a draw sheet holding said strip flexed about the cylinder, said make ready being made of a thickness adapted I for impressing directly thereon.

ALBERT W. COCHRAN. FRED M. YOUNGS.

Images