US2197084A - Printing plate - Google Patents

Description

April 16, 1940.

H. A. sKov PRINTING PLATE I Fil ed Jan. 51. 1939 2 Sheets-Sheet 1 A ril 16, 1940. I

Filed Jan. :51, 19:9

H. A. sKov 2,197,084

PRINTING PLATE 2 Sheets-Sheet 2 Fig.6

I responding to that of the cylinderstill have- Patented Apr. 16, 1940 UNITED STATES- P'ATENT o1=1=1cE Application January 31, 1939, Serial No. 253,898 In Denmark June 8, 1838 10 Claims. (01. lei-401.1

The invention relates to a method to apply type forms or the like printing means to rotary press cylinders and to a device for carrying out the said method.

In the following specification and claims the expression type form" comprises other suitable printing means. a

In rotary and corresponding printing machines printing with rotary printing forms the forms are subjected to a deformation if the type form is bent to suit the printing cylinder.

Owing to this bending the printing surface of the type form is deformed, as its dimensions in the direction of the axis of the printing cylinder .are unchanged, but it is stretched in the circumferential direction.

This deformation of the printing surface is of no importance in the printing of newspapers and the like, but it prevents the printingin rotary presses by normal methods of such printed matters as e. g. drawings, maps and the like, upon'which precise measurements are afterwards v to be taken, or matters which for other reasons must be so exact that the printing surface of the type form must not be subjected to extension in one direction owing 'to the above mentioned bending of the type form to suit it to the printing cylinder.

Printing 'forms. are known intended for attachment on printing cylinders, which printing forms-although shaped with a curvature cora correct printing surface. These printing forms are mainly intended for use in connection with printing on a single press having both one flat and one or more cylindrical printing surfaces intended for muiti-colour work. The production of such printing forms is complicated and presumes that the printing surface is an electrotype shell or the like.

It is further known to produce printing plates made of rubber and intended for use on rotary printing presses. When producing these printing plates, the matrix from which the plates are molded is bent so that the printing image thereon contracts a little. The rubber plate is then produced so as to correspond to the compressed printing surface on the matrix, and the rubber is vulcanised. The printing plate thus produced and consisting of rubber will, when applied on the printing cylinder, be subjected to such a deformation that the printing-surface is stretched, thereby becoming correct.

The present invention purports the elimination of the difficulties attaching to the aforementioned processes.

According to the present invention, a plane,

type form, for example a rubber printing plate, is used. This type form is according to the invention aflixed to the curved outer side of a carrier consisting of resilient material, thus imparting to the originally plane type form a deformation resulting in a stretching of the printing surface. The said carrier with the attaching type form is then aflixed to the printing cylinder. According to the invention the carrier possesses a rear face shaped in such a manner for example curved-that the carrier, when the rear face is pressed home so as to lie up against the outer surface of the printing cylinder, will of its own accord bend in such a manner that the printing surface of the type form will thereby be compressed (staved). Thereby the stretching imparted to the printing surface of the type form through being affixed to the curved outer surface of the carrier is neutralised.

In practice, for example, the type form may be made in the shape of a relatively thin plane plate, one side of which forms the printing surface while its rear side is intended to be secured to a carrier, the outer surface of which forming part of a cylindrical surface of revolution, the radius of curvature of which is shorter than desired for the printing surface during the printing operation, and if the rear face of the carrier is at the same time shaped as part of a cylindrical surface of rotation with a still shorter radius of curvature than that of the outer surface, it will be possible to nullify, at the fixation of the carrier to the printing cylinder, the deformation which the printing surface got when the type form was applied to the outer surface of the carrier. There are no practical difficulties in suiting the radius of curvature for the outer surface and the rear surface of the carrier in relation to one another and to the radius of curvature of the printing cylinder in such a way that the printing surface will be correct when the carrier with the type form thereon is applied to the printing cylinder.

In practice the shape and dimensions of the carrier may profitably be suited to the print to be produced; it may e. g. be a column of a newspaper or only a single small sheet, such as e. g. a label, a trade-mark or the like. When printing newspapers, preferably a plurality of carriers with printing surfaces are employed, each printing a column. Whether the carrier be long or short in the longitudinal directic-n of the printing cylinder, reinforcements (or only one at predetermined mutual distances.

The accompanying drawings show, by way of a" practical example, what is necessary to make the invention understood, the example chosen being a device which may be used in the printing of newspapers or the like. I

Fig. l is an end view of part of a printing cylinder with a number of carriers amxed thereon, of which the left hand and centre carriers are of identical shape, whereas the right hand carrier is shown in a modified constructional form,

Fig. 2 is a plan view of one of the carriers shown in Fig. 1,

Fig. 3 is a cross-section through a carrier and the type form mounted thereon and of the printing cylinder, to which the carrier is secured by means of a securing bolt,

Figs. 4 and 5 illustrate that the printing cylinder may be shaped otherwise than as a cylindri-= cal su'rfaceof revolution, r

Fig. 6 is a schematical side view of a printing machine for industrial use, and

Fig. 7 is the printed product in larger scale.

Referring now to Figs. 1, 2 and 3, I is the printing cylinder, the cylindrical outer surface of which is designated by v. 2 designates carriers, and considering the left one in Fig. 1 it will be seen that its outer surface 3 forms part of a cylindrical surface of revolution. The radius of curvature R of this surface is shorter than the radius of curvature T which the printing surface t is desired to have during the printing operation. The radius of curvature T in Fig. 1 Y must be imagined to end at the same or practically the same point as the radius of curvature V of the outer surface 1) of the printing cylinder, namely at a point representing the axis of the printing cylinder. The rear face 17 of the said carrier forms part of a cylindrical surface of revolution, the radius of curvature r of which is still shorter than the radius of curvature R of the outer surface 21. To the surface 1 of the carrier is applied (e. g. stuck) a type form 3, which must be imagined to consist of a relatively thin plate of a flexible material, e. g., caoutchouc or a weak metal. The outer surface of the type form formsthe printing, surface, which will, therefore, be more or less broken.

When the type form 3 is stuck or otherwise applied to the outer. surface 11 of the carrier, the printing'surface (which was when produced plane and, therefore, correct) of the type form will be deformed in one direction, as at its sticking to the carrier 2 an extension of the printing surface t will take place in the direction trans? verse to the carrier.

The carrier in the left side of Fig. 1 must be imagined, as that of Fig. 3, tohave one or more reinforcements 4 embedded-in the resilient material, e. g. rubber, of which the carrier consists. The reinforcement 4, Fig. 3, is rigidly connected The said reinforcement is prefer-' with a securing bolti, which can be inserted through a corresponding guiding hole 6 in the printing cylinder I. If the carrier is clamped to the printing cylinder by means of the nut 'l, the rear face b of the carrier will be tightened against the outer face 22 of the printing cylinder. Hereby the carrier will be deformed, so that the printing surface t will lie on a cylindrical surface of revolution with the same or-practically the same axis as the printing cylinder.

The presupposition of the printing surface being correct and lying onthe said cylindrical surface of revolution is that the radii R and r of curvature are correctly suited to each other and in relation to the radius of curvature V of the printing cylinder, but this will cause no difficulties in practice. It isconsidered by and for itself also a presupposition thatthe thickness of the type form is taken into consideration, as the said thickness will determine the stretching of the printing surface t when the type form degree to whichthe printing surface t is broken.

On the amxture of the type form to the outer surface of the carrier the type will be bent with a neutral line situated a little below half the height of the type form. The thickness of the carrier is determined by the radii R. and r and chiefly decides the compression of the printing surface t of the type form on the aflixture of the carrier to the printing cylinder. During this aflixture the carrier 2 will be bent with a neutral line situated alittle above half the height of the carrier, as it must be remembered that during this bending the carrier and the type form form a connected whole.

The method according to the above described performance of the invention thus is that the printing surface t of the type is'first produced while the type form is plane. The so produced type form (which is plane and correct) is then stuck to the curved outer surface 1 of the carrier, whereby the printing surface t will be deformed and stretched in the direction indicated in Fig. 2 by the double arrow 8, while it is not deformed in the direction of the double arrow 9. By the fixation of the carrier with the rear face b pressed against the outer face 1 of the cylinder the said deformation of the printing surface will be.

nullified.

The printing takes place in the same way as ordinary rotary printing, and after the printing the carriers 2 may be removed from the printing cylinder and replaced by other carriers 2 with other type forms 3. The carriers removed from Iii vided each with. a securing bolt 5. If desired,

the reinforcement may take the form of a single long rail with a number of bolts 5. The bolts 5 and the corresponding, guiding holes 6 in the printing cylinder ensure that the carriers-2 and, with them, thetype forms will assume correct positions onthe printing cylinder and in relation to each other, as a considerable number of carriers are, as a rule, arranged on one and the correspondingly exact.

same printing cylinder, e. g. when printing newspapers a series of carriers corresponding to one or more columns side by side.

The rectangular field l shown in Fig. 2 may for instance be the printing surface for a map or another print, on which measures are to be taken, or which must for some other reason be This is obtained by the two above mentioned oppositely directed deformations of the printing surface t, which are so suited as very exactly to nullify each other.

Fig. 1 shows two different constructions of carriers with type forms thereon, the printing surfaces of which are designated by t. Common to the said three carriers 2 is that their lateral surfaces are so formed that they will not meet each other until the rear faces b meet the outer surface 2) of the cylinder. Then the lateral faces will meet each other along the planes indicated by the lines S-S in Fig. 1.

The rear faces b need not have the shape of cylindrical surfaces of revolution, and in Fig. 1

the right carrier indicates that the rear face b may be composed of plane pieces, so that the rear face has only substantially the same shape as the rear faces of the other carriers shown.

On the carrier shown in the right side of Fig. 1 the outer surface y has a smaller area than the corresponding outer surface of left carrier in this figure. It may insome cases be advantageous thus to reduce the outer surface of the carrier to give it the same dimensions and form as the bottom of the type form to be applied, e. g. stuck, to the outer surface of the carrier. This is particularly important .in the printing of labels, trade marks or similar print with e. g. circular outline. The sticking-on is facilitated and correct sticking-on ensured, when the outlines of the two parts correspond with each other.

It is supposed in the above that the outer surface 12 of the printing cylinder forms a cylindrical surface of revolution, but this is not necessary, as the carriers 2 may as well have a rear face intended to be pressed against an outer surface of a printing cylinder of other form. By way of example only Figs. .4 and indicate that the outer face of the printing cylinder may be waved and have concave or convex faces, against which the rear faces b of the carriers are tightened. If the outer surface 12 of the cylinder, instead of being cylindrical, is presumed to be shaped with a plane surface underneath each individual carrier, then this will not make any difference, provided that the rear faces I) on the carriers are given a slightly lesser degree of curvature. Expressed in other words, it will not alter the effect, if the low degree of curvature on the-cylinder underneath the carrier is imagined as being ,cut away from the cylinder and instead transferred to the rear face of the carrier. The cylinder may, instead of having a plane surface underneath'each individual carrier, be presumed to be of a shape as shown in Fig. 5. Here the cylinder possesses underneath each individual carrier a curved elevation and in this case a corresponding portion shall be imagined as being cut off from the rear face of the carriers shown in Fig. 1. Fig. 4 shows the cylinder provided with concavities underneath the individual carriers, and in this case the concavities in the cylinder shall be imagined as being neutralised by the addition of the corresponding portions to the rear face of the carriers. Those carriers which shall correspond to the-cylinder in Fig. 4 will thus appear with a rear face almost plane. Nothing inherently prevents the outer surface of the printing cylinder being so shaped that -the carriers must be curved in a direction opposite to that shown in Fig. 1 or, possibly, so that the concavities of their outer and rear faces face each other.

If the carriers 2 are not to lie close to each other as shown in Fig. 1 their lateral faces may be parallel to the axis of the bolt 5, as indicated in Fig. 3 by dotted lines.

The method and devices, which are described, in the above substantially in connection with normal printing, may be employed in every kind of rotary printing, where it is important to produce print without the deformation occurring from the otherwise normal bendingof the type form to suit it to the printing cylinder. The invention is applicable to rotary printing machines for industrial use and for printing of all conceivable prints on the most varying industrial products, as it is a great advantage that a carrier with its printing surface may be quickly removed from the cylinder and replaced by another carrier with another printing surface. Owing to the guiding holes 5 of the cylinder this change of printing surfaces can take place with absolute certainty that a correct position of the carrier on the printing cylinder will always be secured.

- Fig. 6 shows diagrammatically a rotary printing press built for the'printing of labels or like marks on a thin aluminium strip from which blanks are subsequently to be stamped for bottle capsules. The type forms are on the machine shown in Fig. 6 afflxed on the printing cylinders.

by the process according to the invention and by the means through which this process is performed, more particularly the carriers 2. In Fig. 6, 5| denotes the machine's frame. 52 is a cylinder or pin upon which has been inserted a wound coil 53 of that metal strip upon which the machine shall imprint the labels or like markings. The metal strip 54 proper is advanced, as shown by Fig. 6, through three consecutive pairs of cylinders consisting of bottom cylinders 55 and top printing cylinders l corresponding to those shown in Fig. 1. Each of these printing cylindersis in Fig. 6 seen to have aflixed eight carriers 2 on whose outer sides type forms are attached corresponding to the type forms t in Fig. 1. The number of cylinder pairs may be increased or reduced, all according to the number of colours with which it is desired to print.

All type forms on the carriers 2 on the printing cylinder l on the left hand side of Fig. 6 are identical and aflixed identically and colour is applied to all of them from the colour cylinder 56. The printing cylinder on the left hand side in Fig. 6 must e. g. be imagined as imprinting upon the metal strip 54 the ring 51 shown in Fig. 7, in red colour.

Similarly, the middle printing cylinder l shown in Fig. 6 must be imagined as printing, e. g. the square 58 shown in Fig. 7, in yellow colour.

Similarly, the right hand printing cylinder I shown in Fig. 6 must be imagined as printing, e. g. the spot 59 shown in Fig. '7, in blue colour.

In order to ensure that all the imprints 51, 58 and 59 will be applied in the exact relationship to one another, and that the subsequent stamping out of the bottle capsule blanks shall take place in the correct manner so that the imprint comes out in the correct position on the blanks, the metal strip 54, Fig. 7, is usually furnished with guide holes 60, the printing machines advancement cylinders, i. e. the bottom cylinders 55, being at the same time provided with corresponding guide pins which engage with the holes in the strip 54.

The printed and, possibly, by special means dried strip 54 is finally wound up into a coil 6| on a cylinder or pin 62.

I claim:

1. A methodfor producing a cylindrical printing surface comprising distorting a plane type form in one direction by permanently amxing said form to a curved resilient carrier and then again distorting said form on said carrier in the opposite direction in applying said form and carrier to the printing cylinder.

2. A method for producing a cylindrical printing surface comprising stretching a plane type form by permanently amxing said form on a curved resilient carrier and then compressing said type form on said carrier in applying said form and carrier to the printing cylinder.

3. A method for producing a cylindrical printing surface. comprising distorting a plane type form by permanently afiixing said form on a curved surface of a resilient carrier having a radius of curvature less than that of the final printing surface and then again distorting said form in applying said form and carrier to the printing cylinder.

4. Acylindrical printing surface comprising a printing cylinder, a carrier carrying a distorted type form permanently aflixed thereon and said carrier being of resilient material and of such form so that when applied to said cylinder the outer surface thereof carrying said type form is compressed to neutralize approximately the distortion of said type form. 5. A cylindrical printing surface comprising a printing cylinder, a carrier having a distorted type form permanently affixed on theouter surface thereof and said carrier being of resilient material and having a contour at the surface contacting said cylinder different from the printing cylinder surface so that when applied thereto the outer surface is compressed to neutralize approximately the distortion of said type form.

6. A cylindrical printing surface comprising a printing cylinder, a carrier having a distorted type form permanently aflixed on the outer surface thereof and said carrier being of resilient material and having a curved contour at the surface thereof contacting said cylinder with a radius of curvature less than the radius of curvature of said printing cylinder so that when applied to said printing cylinder said outer surface is compressed.

7. A cylindrical printing surface comprising a I printing cylinder, a, carrier having a distorted type form permanently aflixed on the outer surface thereof and said carrier being of resilient material and having a curved contour at the surface thereof contacting said cylinder with a radius of curvature less than the radius of curvature of said printing cylinder to such an extent that when applied to said printing cylinder said outer surfaceis compressed to neutralize approximately the distortion of said type form. 8. A cylindrical printing surface comprising a printing cylinder and a resilient type form carrier mounted thereon with the outer surface thereof in a state of compression.

9. A cylindrical printing surface comprising a printing cylinder, a resilient type form carrier mounted thereon with the outer surface thereof in a state of compression, a reinforcement embedded in said carrier and means for clamping said carrier to said cylinder cooperating with said reinforcement.

10. A cylindrical printing surface comprising a printing cylinder, a resilient type form carrier mounted thereon with the outer surface thereof in a state of compression, a. reinforcement embedded in said carrier and means for clamping said carrier to said cylinder cooperating with said reinforcement, and guiding means in. said A0 cylinder cooperating with said clamping means. HENRY ARNOLD SKOV.

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