US3537395A - Saddles for flexible thin printing plates - Google Patents

Description

United States Patent [72] Inventors Roy W. Prince Lexington, Massachusetts; Manuel C. Uy, Glen Burnie, Maryland [21] Appl. No. 713,956 [22] Filed March 18, 1968 [45] Patented Nov. 3, 1970 [73] Assignee W. R. Grace & Co.

New York, New York a corporation of Connecticut [54] SADDLES FOR FLEXIBLE THIN PRINTING PLATES 6 Claims, 5 Drawing Figs.

[52] 11.8. C1 101/378, 101/415.1 [51] Int. Cl B41t27/06 [50] Field ol'Search 101/378, 382, 387, 415.1

[56] References Cited UNITED STATES PATENTS 2,771,031 11/1956 Knapp 101/415.1 2,966,848 1/1961 Faeber 101/378X 2,970,540 2/1961 Wirth l01/4l5.l f

3,045,595 7/1962 Guriw 101/415.1 3,083,737 4/1963 Mestral 26/9X 3,136,026 6/1964 Mestral 26/2X 3,154,837 11/1964 Mestral 26/2X 3,237,558 3/1966 Fagg 101/378X 3,353,481 11/1967 Antonucci 101/382X 3,376,814 4/1968 schollenberger, 101/378UX 3,384,014 5/1968 Berg 101/415.l 3,127,834 4/1964 Tyma et a1. 101/4l5.l

Primary Examiner Robert E. Pulfrey Assistant Examiner- Eugene H. Eickholt Att0rney- Richard P. Plunkett and Kenneth E. Prince Patented Nov. 3, 1970 Sheet 1 012 INVENTORS R0 y W. Prince Manuel 0. Uy

BY fi ATTORNEY Patented Nov. 3, 1970 Sheet of 2 v I NVENTO S Roy W. Prince Manuel 6 Uy SADDLES FOR FLEXIBLE THIN PRINTING PLATES In the printing field today, especially in the newspaper business, a large number of rotary printing presses having cylinders originally designed for stereotypes, are widely employed. With the advent of photocomposition, flexible, thin plates from photopolymerized or photocured polymeric systems and metal photoengravings are now being employed. However, with polymeric and photoengraved plates, it is not necessary to form plates of the same thickness as previously formed metal stereotypes. Obviously since existing presses are made for metal stereotype plates of preset, relatively thick dimensions, the adaption of the presses for thin flexible plates generates several problems. For example, it is necessary that the new system for the thin plates be formed so as to have substantially the same thickness as the normalmetal stereotype plate in order to use existing presses and cylinders. Additionally, the plate must be easily adjusted to register true on the press. Furthermore, it is necessary that the plate be clampable by conventional existing means and be readily removable from the cylinder in the shortest possible time.

It is obvious that if a printing cylinder which is adapted for reception of stereotype plates, is to be mounted with a thin flexible printing plate instead of the normal stereotype, a backing plate or saddle of sufficient thickness in combination with the thin flexible printing plate to essentially correspond to the thickness of the stereotype must be employed. M oreover, said backing or saddle should be of sufficient rigidity to withstand the pressure applied when the saddle with plate attached thereto is clamped on the printing cylinder.

One method of attachingthe thin flexible printing plate to the saddle that has been suggested by the prior art is adhesion caused by gluing the printing plate on to the saddle, after which the saddle is mounted on the printing cylinder in the same manner as the stereotype plate. This method, however, has the drawback that the rigidity of the adhesive bond prevents subsequent registering and adjustment. Additionally, after use the removal of the plate from the saddle can cause damage to the saddle and/or the plate thereby curtailing its useful life. Another drawback to this system is the extended clean up time necessary to remove the adhesive from the saddle. Another method of adhering printing plates to printing cylinders is the use of magnetic force or vacuum. However, such systems contemplate printing cylinders of intricate design and of sufficient diameter to make up the difference between the thickness of the stereotype and the thin flexible printing plate. Additionally, such systems preclude the use of stereotypes on the printing press and thus precludes flexibility in the system.

Still another method of affixing thin printing plates to printing cylinders adapted for stereotypes is the use of a support adapted to engage thin printing plates by means of hooks which extend through said printing plate into the printing area. Such a system has the drawback that said hooking elements could engage and damage the material receiving the print from the printing plate.

One object of the instant invention is to provide an arrangement for mounting thin flexible printing plates on printing cylinders of rotary printing presses normally designed for stereotypes. Another object of the instant invention is to provide an arrangement whereby rotary printing presses having printing cylinders designed for stereotypes can convert readily to the employment of thin flexible printing plates. Still another object of the instant invention is to provide a saddle for mounting thin flexible printing plates which permits adjustment and register thereof. Yet another object of the instant invention is to provide a saddle for mounting thin flexible printing plates which device affords ready removal of the printing plate therefrom. I

These and other objects of the invention are accomplished by providing thin printing plates with either or both out out portions for the engagement of locking means, e.g. fingers, pins or hooks or adhesive bonding means at their two transverse edge regions. The cut out portions or adhesive bonding means or both are then engaged in the recessed portion traverse the width of the underside near each end of a saddle with hooks, pins, locking means or adhesive bonding material to maintain the printing plate in register with said saddle. The use of the underside ofthe saddle to register and affix a thin flexible printing plate thereto insures fullest employment of the printing face of the saddle and assurance that the material to be printed on won't be torn by locking arrangements projecting from the printing face of the saddle.

The various and sundry novel features of this invention are pointed out in the claims annexed to and forming a part of this specification. The invention will now be more fully explained with reference to the annexed drawings which constitute a part of this application. Although the saddle system described herein is operable for both rotary printing cylinders and flat bed presses, for purposes of explanation the specification description which follows will refer to arcuate saddles for rotary printing cylinders.

Reference is now made to the drawings wherein similar reference numbers refer to similar parts throughout the various views:

FIG. 1 is a cross-sectional view of the saddle and flexible printing plate in an assembled relationship mounted on a printing cylinder;

'FIG. 2 is a perspective view of the underside of the saddle showing the-recessed portion, the bar attachable therein and the flexible printing plate;

FIG. 3 is an exploded cross-sectional view of one method of attaching the printing plate to the saddle mounted on a printing cylinder;

FIG. 4 is an exploded cross-sectional view of another means of attaching the printing plate to the saddle which is mounted on the printing cylinder; and

FIG. 5 is still another exploded cross-sectional view of another method of attaching the printing plate to the saddle which is mounted 'on a printing cylinder.

With reference to the drawings, a flexible printing plate 10 with a raised image or relief printing portion ll is mounted on a saddle 12 as shown in FIG. 1. The saddle 12 consists of a rigid'material of uniform thickness and of generally arcuate shape. The saddle is mounted on a printing cylinder I3 equipped with either fingers for tension lockup by exten sion into tapered grooves 15 in the-saddle or conventional compression lockup by contacting rings around the circumference of the cylinder with the bevelled edges of the saddle 30. The thin printing plate 10 is provided at its respective op-. posite straight traverse edge portions with a number of spaced cutouts 1 6, which cutouts accept and have projected therethrough register pins 17 mounted in the recesses 21 traversing the width of the underside near each end of the saddle l2. Additionally,-depending on the type of bonding of the printing plate to the saddle, the printing plate may have interspaced between the cutouts for the register pins, openings 18 for the projection therethrough of fastening means 19 to secure a register bar 20 into the recess 21 situated transverse the width of the underside near each opposite end of thesaddie 12 thereby tensioning the flexible printing plate 10 aroun the curvature of the saddle l2.

In referring to FIGS. 3-5, it should be noted that the foot or end portion 22 of saddle I2 is of such thickness as to allow the inclusion of the thickness of the backing material for the printing plate to pass there between it and the printing cylinder 13.

Various means can be used to hold the ends 23 of printing plate 10 in the recess position 21 of saddle 12. One method as previously described supra and as shown in the views in FIGS;

elements 24, 25 are shown in FIG. 4. Said elements can beformed of synthetic materials such as nylon or similar material and after thermal treatment one element is maintained in the form of loops 24 and is adhered to the back portion 28 of recess 21 of the saddle 12 whereas the other element in the form of hooks 25 is adhered to the ends 23 of the printing plate. Elements 24 and 25 are contacted to form a separable fastening device. Such elements are known from U.S. Pat. Nos. 2,717,437; 3,009,235; 3,083,737; 3,114,952; 3,136,026 and 3,154,837 all assigned to Velcro Company. If desired, elements 24 and 25 can have apertures therein for the passage of register pins 17 mounted in the back portion 28 of recess 21 in saddle 12. Still another method of holding the printing plate on and in register with the saddle is shown in FIG. 5. Therein a plastic material 26, e.g. polyethylene having male buttonlike prongs 27 extending therefrom is adhered to the back portion 28 of recess 21 and similar plastic material 26 having female openings 29 registerable with said buttonlike prongs 27 is adhered to the ends 23 of the flexible printing plate 10 in a manner such that the openings 29 extend therefrom. By means of snapping said male buttonlike prongs 27 into said female openings 29, the printing plate is adhered to and in register with saddle 12.

The flexible base of the printing plate is preferably composed of plastic e.g. Mylar" but can also, if desired, be composed of rubber, aluminum or other metal foil. The printing or relief surface of the printing plate 11 is preferably composed ofa polymeric or plastic material, e.g. a synthetic organic resin or polymer but can also be composed of rubber, molded plastic, metal, etc. For example, in its preferred form it may be composed of a photocured polymer made after the manner described in U.S. Pat. application Ser. No. 674,773 filed October 12, 1967 and assigned to the same assignee. Additionally, it can be composed of a photopolymerized addition polymer as described in U.S. Pat. Nos. 2,760,863; 2,791,504; 2,927,002; 3,024,180 and 2,923,673.

The assembled flexible printing plate and saddle are fastened on to the printing cylinder or flat bed by conventional means. For example a tension lockup consisting of fingers extending from the circumference of the printing cylinder into slots on the inner arcuate surface of the saddle at each end can be employed. Additionally, the saddle can also be used on rotary presses equipped with rings for compression lockup.

' The saddles operable in the instant invention are of rectangular shape and they can be of either flat bed or arcuate configuration. The saddle should be of sufficient thickness and rigidity that it is stiff and does not flex appreciably on mounting. A saddle thickness of about three-sixteenths to about three-eighths inches is operable for flexible plates ranging in thickness from 10 to 80 mils.

The recess portion of the underside of the saddle across the width thereof is located approximately one-eighth to onefourth inch from each opposite end of the saddle and has a width of approximately one-fourth to one-half inch and a depth of approximately one-eighth inch. These dimensions are for a printing plate having a printing surface of approximately 22 inches in length. For larger or smaller printing areas the dimensions of the recess can be varied as the need arises.

The saddle can be made from various materials. Operable materials include, but are not limited to, metals, e.g. magnesium, aluminum, steel, etc., hard semi rigid plastics, e.g. phenol formaldehyde, acrylic, phenolic, nylon and the like light weight materials and fiber glass-impregnated cellulosic materials.

Advantages of the instant invention include the mounting of flexible printing plates on printing cylinders using conventional printing cylinders and lockups. The saddle is reuseable and the polymeric printing plate can be readily removed therefrom to be reused at a later date, thereby allowing the printer to maintain a minimum inventory of saddles and assuring the reuse of the flexible printing plate in the future.

We claim:

1. An arrangement for mounting on a printing cylinder which comprises in combination, a curved stiff rectan ular backing plate of one-piece construction having general y U- shaped recess portions transverse its width on its underside near to but spaced from each opposite end, said ends having a rounded configuration, a flexible printing plate disposed over said backing plate and of a length sufficient to extend around the opposite rounded ends of said backing plate and across the recess portions, the thickness of said backing plate between said recesses and said opposite ends being less than the thickness of said backing plate between said recesses by an amount substantially equal to the thickness of said printing plate, and two separable securing bars associated with register pins for engagement with openings in the printing plate, said separable securing bars securing the printing plate to the backing plate within the generally U-shaped recess portions by a fastening means.

2. The arrangement of claim 1 wherein tapered grooves are provided intermediate the recess portions for tension lockup on a printing cylinder.

3. The arrangement of claim 1 wherein the register pins are secured within the recess portions and projected through the printing plate and through register apertures disposed in said securing bars.

4. The arrangement of claim 3 wherein screws secure the securing bars within the recesses to the backing plate.

5. The arrangement of claim 1 wherein the separable bars are each formed of two elements having engaging hooks and loops. I

6. The arrangement of claim 1 wherein male buttonlike prongs extend from the separable bars within the recesses for receiving openings of the printing plate.

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