US2285116A

US2285116A - Printing plate

Info

Publication number: US2285116A
Application number: US234536A
Authority: US
Inventors: William F Grupe
Original assignee: Interchemical Corp
Current assignee: Interchemical Corp
Priority date: 1938-10-12
Filing date: 1938-10-12
Publication date: 1942-06-02
Anticipated expiration: 1959-06-02

Description

v2 Sheets-Sheet 1 lNVE WIHIAM Ff W. F. GRUPE PRINTING PLTE Filed vom; 12, 1938l Jung 2, 1942.

NTOR G12 u P e ATTORNEY June 2, 1942. w. F. GRUPE PRINTING PLATE 2 Sheets-Sheet 2 Filed Oct. 12, 1938 q Sg lNvEfoR WllmM t, Gupe BY ATTORNEY `desired circumference must ?atented June 2, 1942 2,285,116 PRINTING PLATE William F.

mesne assignments, tion, New York, N.

Grupe, Lyndhurst, N. J., assignor, by

to Interchemical Corpora- Y., a corporation o! Ohio Application october 12, 193s, serial No. 234,536 16 claims. (Cl. iol-415.1)

This invention relates tc', printing plates, and aims to provide a thn,'exible metal printing plate and a method of preparing the same.

In printing a continuous design, and in rotogravure printing upon material fed to the press in web form, it is necessary that the printing Theprinting members used in such printing in the past have comprised heavy, metal cylinders in which the outer printing surface is an integral part of the cylinder, or in which the outer printing surface is provided by a cylindrical sleeve, or shell which fits an inner supporting cylinder. Such cylinders are very expensive: In preparing them for use the pe` ripheral surface must be very carefully ground and burnished to present a smooth surface; the be attained Within exceedingly narrow limits; anda perfectly cylindrical shape must be maintained.

I have discovered that a printing plate may be so formed of a thin, Aflexible sheet of suitable metal, that a sharp edgeis provided at each end of its printing surface. Such a printing plate is inexpensive. It may be wrapped around a supporting cylinder of the type described and claimed in the patent application led by me on January 14, 1937, Serial No. 120,530 (now Patent No. 2,194,424), so as to fit the cylinder perfectly without distortion of the printing surface. The sharp edges provided at the ends of the printing surface may be brought together closely to form an imperceptible joint.

The printing plate which I have invented may be used to advantage in either letterpress or planographic printing, but it is of particular advantage in rotogravure printing, especially when the material printed upon is' in web form. The printing cylinder of a rotogravure press revolves partially submerged in a trough of ink. A doctor blade removes ink from the surface of the cylinder only, and ink contained in the depressions in the cylinder is transferred to the paper printed upon. Accordingly, any perceptible depression or a break in the outer surface of the printing plate at the juncture of the two ends of the plate would retain ink which would the prints produced. By providing a close, imperceptible joint between the ends of the printing plate I have overcome this difliculty.

A printing plate embodying my invention comprises a thin, flexible sheet of metal which consists of an intermediate portion providing a printing surface and two end portions extending cumbersome Y 4members have a continuous unbroken surface.

a sharp angular edge at the junctures of the intermediate portion with the end portions.

A printing plate may be made in accordance with my invention by so forming a transverse bend adjacent each end of a thin, exible sheet of metal that the end portions project inwardly at an acute angle to the printing surface and a sharp edge lying in theplane of the printing I surface is provided along each of those bends.

A specific embodiment of my invention is illustrated in the accompanying drawings, wherein be transferred tof the thickness of the printing plate is exaggerated for purposes of illustration, and in which:

Fig. 1 is a fragmentary section illustrating the displacement of metal along the line of the bend in the printing plate to a point above the plane of the outer surface of the plate; Fig. 2 is a fragmentary section joint between the ends of a printing plate illustrating the mount- 0 ed upon a closed supporting cylinder before metal displaced above the plane of the outer surface of the plate has been removed.

Fig. 3 is a section similar to Fig. 2 illustrating the joint formed after the removal of metal displaced above the plane of the outer surface of the printing plate and also showing another arrangement of the holding slots;

Fig. 3A is a fragmentary sectional view through a flexible sheet showing a method of upsetting the metal at a line of joint before bending;

Fig. 4 is a vertical section of a printing plate mounted on an open supporting cylinder;

Fig. 5 is a vertical section of a printing plate mounted upon a closed supporting cylinder;

Fig. 6 is a fragmentary view taken along the line 6-6 of Fig. 8;

Fig. 'l is a section taken on Fig. 5;

n Fig. 8 is a section taken along the line 8-8 of Fig. 5; and

Fig. 9 is a fragmentary plan view of a portion cfatprinting plate having a longitudinally curved Join The printing plate illustrated in the accompanying drawings comprises a thin, flexible sheet of suitable metal, such as copper, zinc, copper or other alloys and the like. The thickness of the sheet should not exceed one-eighth of an inch,

the une 1--1 of and, for rotogravure, it is preferably about ve length to the circumference of the supporting cylinder indicated generally by the numeral 3 i upon which it is to be mounted, and end portions at acute angles to the printing surface, and has 4, 4. The printing surface of the plate is provided by intermediate portion 2. A sharp angular edge, of 90 or less, is provided at the junctures of

end portions

4, 4 with intermediate portion 2.

A specic illustrative method of making such a printing plate in accordance with my invention is as follows: The outer surface of .an intermediate portion 2 of a sheet of thin, flexible metal is prepared for printing in known manner. Thereafter bends 5, are formed adjacent each end of the sheet so that end portions 4, 4' project below the intermediate portion at approximately right angles thereto. Ordinarily, when such bends are formed their outer edges are rounded. If the sheet were then mounted upon a supporting cylinder 3 so that the

end portions

4, 4 were brought into contact, a valley would be formed between the rounded edges of bends 5, 5' which would extend below the outer, printing surface of the plate.

An imperceptible joint between the

end portions

4, 4 is provided by forming at the junctures of intermediate portion 2 with end portions 4, 4', sharp edges lwhich flteach other closely when the sheet 4is mounted upon supporting cylinder 3, and the

end portions

4, 4. are brought into contact. This is accomplished by displacing a portion of the metal along each of the

bends

5, 5 to, and preferably beyond, the plane of the outer surface of the sheet. This is done, in the formV illustrated, by swages applied after the

bends

5, 5 are formed. The ends of the sheet I are hooked over an inner swage 6, an outer swage 'I is forced against the intermediate portion 2 of the sheet above the inner swage 6, and an end swage 8 is then forced against the end portion 4 or 4'. As illustrated in Fig. 1, the swages 6, I and 8 displace portions Il),` I0 of the metal along the respective bends 5, 5', so that the portions I0, I0 form a continuation of the end portions 4, 4' projecting to the plane of the printing surface, and 'preferably beyond it, as illustrated. The printing plate thus prepared is wrapped around an open supporting cylinder 3. The cylinder is closed so that end portions 4, 4', which serve as inwardly projecting ears, are tightly held in close contact with each other as illustrated in Fig. 2. Any part of the displaced metal I0, I0 which projects above the cylinder is then removed by rolling, grinding or cutting, a close imperceptible joint between end portions 4, 4' extending to the periphery of the printing cylinder is provided, as illustrated in Figs. 3 and 5, and the printing cylinder is ready for use. y

Another method of forming a printing plate in accordance with my invention, comprises suitably upsetting the metal of a plate as by means of a die and press, into two substantially parallel sharp edged creases or lines IOA (see Fig. 3A) which are accurately spaced from one another a distance equal to thecircumference of the desired printing cylinder and afterwards constitute the desired sharp edges of the printing plate. The surface between the creases is the intermediate or printing portion 2, and the metal outside or beyond the creases may be cut and/or bent to form the desired end portions 4, 4'. Then the plate is curved or bent about the cylinder 3, suitably fastened, and any metal projecting above the smooth cylindrical surface removed in the manner indicated above. It will be apparent that this method of forming the plate is, at least In its preliminary steps, substantially the reverse of that described above.

After the printing required of a given plate has been accomplished, the cylinder 3 may be opened, the plate may be quickly removed, and another plate may be mounted upon the supporting cylinder 3. The used plate may be stored and, if duplicate prints are required at a future date, it may be easily remounted upon the supporting cylinder.

Although the outer surface of the intermediate portion l2 of the printing plate is ordinarily prepared for printing before the

bends

5, 5 are formed in the plate, there are occasions when a continuous design is required. In that event, the etching of the outer printing surface of intermediate portion 2 may be postponed until after the plate has been mounted upon its supporting cylinder 3 and any metal portions Il), I0' projecting above the printing surface' have been removed. rThe supporting cylinder 3 illustrated in the drawings comprises two partial cylinders I2, I2' mounted for limited rotary movement with respect to each other upon an axial shaft I3 by means of webs I4, I4. y

To permit the supporting cylinder 3 to be opened, so that the printing plate may be mounted upon it, opposed. ends I5, I5 of the partial cylinders I2, I2' are slotted to form projecting plates I6, I6' which dovetail as illustrated in Fig. 6 and provide a supporting surface for the printing plate which is, for all practical purposes, continuous.

Mechanism is provided for opening the cylinder 3 and for closing it tightly so that the

end portions

4, 4 of the printing plate, which serve as inwardly projecting ears, are tightly held in close contact with each other and the printing plate is held in place securely: A series of bolts I'I are fixed to partial cylinders I2 along a line parallel to its axis, so that they may be rotated freely but longitudinal movement 0f the bolts II with respect to partial cylinder I2 is prevented. The threaded ends of the bolts I'I engage screw threads provided in the member I8 xed to partial cylinder I2 along a line parallel to its axis. The heads I9 of the bolts I'I are provided with gear teeth to form pinions which mesh with worm gears 20 fixed on a shaft 2| which extends through partial cylinder I 2 parallel to its axis. Rotation of the shaft 2I and of worm gears 20 xed thereto in mesh with the gear teeth extending from bolt heads I9 causes the bolts I'I to be screwed out of, or into, the member I8 to open or close the cylinder so that the jaw faces 22, 22 willpress end portions 4, 4' of the printing plate tightly against each other.

In order that the

end portions

4, 4 may be properly closed throughout the entire length of the cylinder, I have found it desirable to have them slightly curved or bowed longitudinally. That is, each longitudinal end portion 4 or 4' may be curved convexly a very small amount throughout its length. II'hen, when the plate is placed on the cylinder, said cylinder may be closed by so arranging or setting the bolts II and their actuating means that the center bolts will be moved to a completely closed position first, such an arrangement being advantageous, however, regardless of the contour of the longitudinal edge. In this way the center of such longitudinal edge will be closed first and a proper and substantially imperceptible closure will be assured.

In some cases it may also be advantageous to have one of the edges or jaw faces 22,22 curved convexly and the other curved concavely a very slight amount. Such a construction will then provide a longitudinally curved joint 23, as shown in Fig. 9, for example, and completely avoid any wear or jump in the doctor blade asit passes thereover during use of the cylinder.

The respective ends of the cylinder 3 may be closed and tightly sealed to prevent the entry of ink by means of end plates-24, 24' and gaskets 25, 25'. A

Provision is made for holding the printing plate upon the cylinder 3 after it has been placed upon the cylinder and while the cylinder is being closed. Two such provisions are illustrated in Figs. 2 and 3 ofthe accompanying drawings, in which the

end portions

4, 4 are bent to form hooks which t respectively in angularly disposed slots 26, 26' with which the opposed jaw faces 22, 22 of the partial cylinders l2, I2 are equipped.

It is preferred that the distance between the surface of the cylinder and the slots 26 and 2t' be as small as possible, such, for example, as about one sixteenth or one eighth of an inch, in order to reduce the pressure required to eifect a proper closure of the edges of the plate and reduce the tendency of the plate to warp. In this connection, I also' prefer to have the jaw faces 22, 22' disposed at an angle of less than 90 so that the greatest'pressure will be applied at the surface of the plate.

It is to be understood that modifications may be made in the specific printing plate and method of preparing it which I have described without departing from the spirit of my invention.

What I claim is:

l. A printing plate comprising a thin, flexible sheet of metal which consists of an intermediate portion providing a printing surface andtwo end portions bent at right angles to the printing surface, and having metal adjacent the lines of bend displaced so as to form sharp right-angle edges at the junctures of the intermediate portion with the end portions.

2. A printing plate comprising a flexible sheet of metal which does not exceed one-eighth of an inch in thickness, and which consists of an intermediate portion providing a printing surface and two end portions bent at right angles to the printing surface, and having metal adjacent the lines of bend displaced so as to form sharp right-angle edges at the junctures of the intermediate portion with'the end portions.

3. A printing plate comprising a flexible sheet of metal which is greater than ve one-thousandths of an inch in thickness, and which consists of an intermediate portion providing a printing surface and two end portions bent at' right angles to the printing surface, and having metal adjacent the lines of bend vdisplaced so as to form sharp right-angle edges at the junctures of the intermediate portion with the end portions.

4. A rotogravure plate comprising a thin ilexible sheet of metal, which consists of an intermediate portion providing an intaglio printing surface and two end portions bent at right angles to the printing surface, and having metal adjacent the lines of bend displaced so as to form sharp right-angle edges at the junctures of the intermediate portion with the end portions.

5. A printingmember for rotary presses comprising the combination, with a supporting cylinder, of a printing plate consisting of a thin, flexible sheet of metal having an intermediate portion equal in length to the circumference of the cylinder and terminating in two end portions bent at right angles to the printing surface and having metal adjacent the lines of bend displaced so as to form sharp right-angled edges at the juncture of the intermediate portion with the end portions and means for locking said plate upon the cylinder so that said edges are in close contact with each other.

6. A method of making a printing plate, which comprises forming a transverse bend adjacent each end of a thin flexible sheet of metal, having a surface which is subsequently to form a printing surface, and displacing .metal adjacent the lines of bend so as to provide along each line of bend an integral sharp and substantially right angle edge formed from said exible sheet of metal and lying in the plane of the printing surface, the sharpness and angularity of said edges being such that when both are abutted together they will form a substantially imperceptible joint. 7. The method of making a printing plate which consists in etching a printing surface on an intermediate portion of a thin, flexible sheet of metal, and in forming a transverse ben'd at each end of said intermediate portion so that the end portions of the sheet project at right angles from the non-printing side of the sheet, and displacing a portion of the metal along each of the bends to the planel of the printing surface.

8. The method of making a printing plate which consists in etching a printing surface on an intermediate portion of a thin, flexible sheet of metal, and in forming a transverse bend at each end of said intermediate portion so that the end portions of the sheet project at right angles from the non-printing surface, displacing a portion of the metal along each of the bends to and beyond the plane of the printing surface, and removing` the portions of the displaced metal which project beyond the printing surface.

9. The method of making a. printing plate for rotary presses which consists in forming a transverse bend adjacent each end of a thin, flexible sheet of metal having a printing surface so that the end portions project inwardly at right angles to the printing surface, causing a portion of the metal of said flexible sheet along each of said bends to form a continuation of said end portions above the plane of the outer surface of the sheet, fixing the sheet upon a supporting cylinder so that the ends are held in close contact with each other, and then removing the portion of metal which projects above the plane of the outer surface of the sheet,

10. The method of preparing a rotogravure plate which consists in etching an intermediate portion of the outer surface of a thin, flexible sheet of metal, forming a transverse bend in each end portion of the sheet so that the end portions project inwardly from the sheet at right angles thereto, causing a portion of the metal of -said flexible sheet along each of said bends to form a continuation of said end portions above the plane of the outer surface of the sheet, xing the sheet upon a supporting cylinder so that the ends are held in close contact with each other, and then removing the portion of metal which projects above the plane of the outer surface of the sheet.

1l. The method of preparing a printing plate which consists in forming a transverse bend adjacent each end of a thin, flexible sheet of metal so that the end portions project inwardly from the sheet at right angles thereto, causing a portion of the metal of said flexible sheet along each cylinder so Ythat the ends are held in close con-' tact with each other, removing the portions of metal which project above the plane of the outer surface of the sheet, and then etching the outer surface of the sheet.

12. A method of making a printing plate for al printing cylinder, which comprises forming two.

substantially parallel sharp edged and substantially right-angle creases in a thin flexible sheet of metal by upsetting the metal,'the distance between such creases being lsubstantially equal to the circumference of the cylinder, and bending the metal outside of such creasesvin a' plane substantially continuous with one surface of said right-angle creases to form means for attaching the plate to the cylinder.

13. A printing plate comprising a thin,V flexible y sheet of metal providing a printing surface and having a sharp longitudinally curved edge at each of its ends, and an angularly disposed attaching portion adjacent each of the respective ends.

14. A method of making a printing plate from athin flexible sheet of metal having an intermediate portion which is adapted to form a printing surface, which comprises forming a transverse bend at each end of said intermediate portion so that the end portionsof the sheet project at right angles from the non-printing side of the sheet, and displacing a portion of the metal along each of the bends to the planefof the printing surface. I

15. As a new article of manufacture, a printing plate produced in accordance with the method of claim 14,

16. A method of making a printing plate from a thin flexible sheet of metal having a. surface which is subsequently to form a printing surface,. which comprises so form-ing a transverse bend" adjacent eachend of the flexible sheet as to provide along each line of bend an integral, sharp and substantially right angle edge formed from said flexible-sheet of metal and lying in the plane ofthe printing surface, the sharpness and angularity of said edges being such that when both are abutted together they will form a substantially imperceptible joint, such forming operation comprising a step 'of bending the flexible sheet, a step of displacing or upsetting the metal of said sheet beyond the surface thereof adjacent the proposed lines of bend, and a step of removing the displaced or upset \metal beyond said surface.

WILLIAM F. GRUPE.