US1669416A - Planographic-printing element and process of making same - Google Patents

Description

May15,192s. 1,669,416

- W. C. HUEBNER PLNOGRAPHIC PRINTING ELEMENT AND PROCESS OF MAKING SAME F1166r oct. 15, 1922 5 sheets-snee: 1

Afro/marne.

May 15, 192s. 1,669,416

' W. C. HUEBNER PLANOGRAPHIC PRINTING 4ELEMENT AND PROCESS OF MAKING SAME Filed oct. 1.6. 1922 srsnee's-snee*v 2 20 am 5M, mf.

Arranz/ Fay/4 May 15, 192s. 1,669,416A

W. C. HUEBNER PLANOGRAPHIC PRINTING ELEMENT AND PROCESS 0F MAKING SAME I Filed Oot- 15', 1922 3 Sheets-Sheet 3 Patented Mnyils, 1928.

UNITED STATES 1,669,416 PATENT OFFICE.

WILLIAM-C. HUEBNEB, F BUFFALO, NEW YORK.

PLANOGRAPHIC]?B.I1"E|?I'JIG. ELEMENT AND .PROCESS-'OF MAKING SAME.

Application illred October 13, 1922. 'Serial No. 594,371.

In direct planographic rinting in which rints are made directly rom metal plates, ithographic stones'and analogous, hard or unyielding printing surfaces, great dithculty is experienced'in attempting to produce high class halftone or similar fine tex-y tured Work on account of the unavoidable unevenness and rigidity of the printing plates or surfaces, the unevenness of the paper or other print-receiving material and the inking rollers, and the consequent great pressure needed to secure fair printed impressions. The result is -a more or less broken impression Where the values are lighter than solid color, and the process requires hard, smooth-surfaced paper for printing. g

The above-mentioned difiiculties are mainly overcome in offset printing by the yieldpression from a'metal or other non-yielding printing plate or element and, in turn, prints the impression upon the 'print receiving surface. Very smooth prints can be made upon either smooth or rough surfaced papers by this method, but the solid colors lack depth or strength because the impression upon the paper is really a second step,

I offset from the first impression made upon the rubber blanket. This shortcoming, in a Way, is true also of the individual dots or values that make up the halftone or color gradation areas, each lacking its real depth of color. Offset printing also has the disadvantage that `it involves more steps, and therefore is slower in make-ready than direct printing. Furthermore, it is not as accurate in register for color Work on account of variations in the surface speeds of the different cylinders of thepress.

One object of this invention is to produce a planographic printing plate or element which is adapted for direct printing and Will give the advantages but overcome the disadvantages above mentioned, of both the ing rubber blanket which takes an ink im-` direct and offset methods of planographi l editions by the direct method, and.

up the values in lights andshadows, and at4 the same time insure smooth, unbroken prints upon either smooth or rough surfaced paper and other print-receivin material; also to provide means where y the -steps and operations now required in offset printing are reduced in number, the presses needed to produce a high class product are simplified, and results are attained in time, cost and qualit of Work that are not possible by other nown methods of printing. Still another object ofthe invention. is to supply a practical method for producing planographie printing plates havingthe before mentioned characteristics and advantages. v

The resilient or yielding printing element is made preferably by mounting suitable elastic or' resilient material, such as a thin sheet or layer of rubber of fine quality, upon a base of metal or other material of a relatively inelastic n'ature adapted to prevent stretching, creeping or distortion 0f the resilient sheet When making prints from the printing element and to insure accurate register and stability of the resilient printing surface thus formed when printing therefrom. The sheet rubber or its equivalent can be mounted directly on a thin, metal plate'or sheet, or on a cylinder, and secured thereon, as by cementing. Or a sheet of tough, even paper or film of other suitable character can be iirst cemented on lthe metal base and the sheet rubber cemented on the paper or film, which forms a binder between the rubber and metal and insures a firm, reliable connection of therubber to the nonextensible base. Sheet rubber or other suitable material can be applied in like manner to the yreverse orvunder side of the metal or base plate for the purpose of producing a cushion under the metal base carrying. the resilient printing surface, or a thin piece of felt or other suitable material can be used alone or with a rubber or othersheet on the reverse side of the printing element, depending upon the nature of the Work to be printed, as illustrated in the accompanyingi drawings in which,

Fig. 1 is a face view of a resilient surfaced printing plate illust-rating one embodiment of my invention. f 'l lFig. 2 is a section thereof indicating diagrammatically by raised portions thereon the ink-receiving portionsof the printing surface. l

Figs. 3 and 4 are views similar to Figs.

'nisA loo 1 and 2 respectively, but showing a negative of the printing image of the plate shown in Figs. 1 and 2.

Figs. 5-14 inclusive are similar sections of different modifications of the invention.

Fig. is a diagrammatic view of a press equipped with a printing element according to my invention.

As shown in Figs. 1-5 inclusive, the printing element consists of shee-t16 of yielding material, preferably rubber of fine quality, which forms the printing surface, and is secured by a suitable cement or binder 17 on a nou-elastic or non-extensible base 18, which preferably is a thin metal plate. The raised and depressed portions indicating the printing image in Figs. 2 and 4 arc greatly exaggerated for the purpose of illustration. In the actual element the surfaces of t-he printing and non-printing portions of the plate are practically in the same plane, as in other planographic plates.

Fig. 6 shows similar rubber sheets 1G and 16a, similarly secured on both faces of the metal base plate 18. The rubber sheet 1Ga on the 'reverse side of the metal plate forms a yielding cushion for the latter.

Fig. 7 shows a printing element similar to that shown in Fig. G except that the cushion 19 on the reverse side of the base plate is made of felt or analogous material.

In Fig. 8 the element is substantially the same as shown in Fig. 6, except that a binder ply of paper or other suitable material is interposed between the rubber cushion 16a and the metal plate 18. This forms a very secure bond between the metal and rubber.

Fig. 9 shows the use of a similar bond 2() in a printing element constructed as in Fig. 7, with a feltv cushion 19.

Fig. 10 shows the use of such a bond 2O between the metal plate 18 and the rubber sheet 16 forming the yielding printing surface.

-F ig. 11 illustrates an element like that shown in Fig. 10, but providedwith a rubber cushion 16a.

The element shown inFig. 12 is similar to that shown in Fig. 11, except that a felt cushion 19 is used.

Fig. 13 shows an element having a rubber printing surface 16 and rubber cushion 16, but employing a bonding ply 20 between the metal plate and each rubber sheet.

Fig. 14 shows a similar combination, except that the rubber cushion is replaced by a felt cushion 19.`

Various different constructions printing element adapting it for different desired results are thus shown in Figs. 5-14, but still other constructions of the printing element'having the yielding printing surface and a base or strengthening part of a character adapted to prevent stretching or distortion of the yielding printing part of the could be usedl It is also possible to mount the yielding material forming the printing surface directly upon a press cylinder or upon a tubular cylindrical base adapted to be mounted in a press, although the thin, flexible plate formation of the printing element,` as illustrated in the drawings, is considered preferable because of various practical considerations.

Different methods can be employed for preparing the rubber or yielding surface of the printing element for printing therefrom, after first cleaning it in any suitable way, to remove all grease or other foreign matter therefrom. For instance, it can be Washed with a solution of muriatic or hydrochloric acid, or acetic acid and salt in water; or the surface can be scoured with any suitable scouring medium.

One method of preparing the printing surface after cleansing it, is as follows First, the surface is sensitized in one of the well known ways used for sensitizing photographic plates or films, then a 'photographic image or images is or are made upon the sensitized rubber surface by exposing the light sensitive coating to light through a positive or negative by photographic contact or projection printing. A greasy or etch-resist solution is applied to the surface of the plate or element, either before or after the exposure thereof to light, and the images are developed with a developing solution of a suitable character, depending upon the nature of the light sensitive coating. This developing solution penetrates the greasy or etch-resist solution and dissolves or removes those portions of the light sensitive coating which were not hardened or fixed by the light action and leaves the underlying portions of the printing surface bare and clean. Then, an inkrepellent solution, such for instance as a nut gall or chromic acid solution, is applied to the printing surface, after which the surface is Washed with water and wiped dry or nearly dry. This completes the preparation of the surface.

If the elementis not to be used for printing therefrom for some time, the printing surface is preferably coated with gum and the gum coating rubbed down smootlr and dry. Thereafter, when the plate is to be used for printing, the gum coating is removed by Washing With clean Water so as to -leave the printing surface as it Was before the application of the gum. Since rubber does not oxidize by exposure to the atmosphere so readily as metal, the gumming of the Surface, which is for the purpose of preventing oxidation, is not so essential with the described rubber printing surface as with a metal plate.

Another method of `preparing the resilient printing surface is to make ink. images upon lOl) that drives the cylinder.

the rubber surface previousl cleaned, as explained, by printing direct y thereon from an original plate suitably inked, by laying down a lithographie transfer sheet carrying the inked images, orl by other methods of applying an ink image on a rubber surface. An ink-repellent solution, such fory example as before mentioned, is then applied to the printing surface, after which the surface is washed with water and wiped dry or nearly so. Water will then adhere to the uninked portions of the surface while the inked portions will repel the water, but will take ink. The surface can, therefore', be damped, inked and prints made therefrom after the manner' of printing from the ordinary planographie printing plates. V

The printing plate or element with the resilient printing surface prepared by either of the methods explained can be mounted upon a flat-bed press, or preferably on a cylinder A of a cylinder press, indicated diagrammatically in Fig. 15, which is suitably constructed so that the resilient printing surface is disposed ona circular line eoincident with or slightly above the line known as the pitch circumference of a gear The print-receiving paper or material B is held in position against the printing surface during printing to receive the inked impression therefrom, by an impression cylinder C having a similar surface diameter. The surface of the impression cylinder can be either hard or yielding, according to the requirements of the work`to be printed, or the impression 'cylinder can be supplied with aresilient surfaced plate with images produced thereon, as before described, and this second plate can be inked and treated to yield impressions on the reverse side of the print-receiving sheet, thus operating as a perfecting press.

When printing from the resilient printing surface having the printing images formed thereon, as explained, the printing surface is damped by ordinary damping rollers or other means, so as to place a thinlihn of moisture over all portions of the surface except where it is repelled by the greasy ink images which, however, will readily take greasy ink from ordinary inking rollers and yield impressions directly upon paper or other suitable print-receiving material. If the greasy ink used is colorless, nonprintable, or not visible, then a water ink can be used to print from the grease repellent parts. The usual damping with water would not then be necessar Fig. l5 shows the printlng element provided at its opposite ends with securing and registering bars 25 which are attached to and remain on the element. These bars are adapted to be removably secured in seats 26 on the press cylinder and to abut against rigid parts on the seats or cylinder to accurately register the printing element both endwise and sidewise on the cylinder, as explained more fully in my Patent No. 1,391,117, datedSept. 20, 1921'.

I claim as my invention '1.,A planographie printing element comprising a thin sheet of rubber having a printing surface provided with a permanent printing image the surface of which is substantially coplanar with said rubber surface, and a substantially non-extensible base to which said rubber sheet `is attached and which prevents substantial stretching of said rubber when printing from said element, said base having a substantially uninterrupted surface forming a continuous backing for said rubber sheet.

2. A planographic printing element having a resilient rubber printing surface provided with ink-retaining and ink-repelling portions adapted when said surface is inked to form an ink image and adapted to produce ink impressions of said image, and a base to which said printing surface is attached and which prevents substantial stretching of said surface when printing therefrom.

3. A planographic printing element having -aprinting surface of rubber provided with ink-retaining and ink-repelling portions adapted when said surface is inked to form an ink image and adapted to produce ink impressions of said image, and means which prevent substantial stretching of said rubber.

4. A planographic printing element having a printing surface of rubber provided with a permanent printing image, the surface of which is substantially coplanar with' said printing surface, and a substantially non-extensible base to which said rubber is att-ached and which prevents substantial stretching of said rubber, said base having a substantially uninterrupted surface forming a continuousbacking for said printing surface.

5. A flexible planographic printing elementcomprising a thin sheet of rubber having a printing surface provided with a permanent printing image the surface of which is substantially coplanar with said rubber printing surface, and a thin flexible but substantially non-extensible base to which said rubber sheet is attached and which prevents substantial stretching of said rubber when 'printing from said element, said base having a substantially uninterrupted surface forming a continuous backing for said rubber sheet.

6. The process of making a planographic printing surface which is resilient in a direct-ion normal to said surface but' is substantially non-extensible in directions V'parallel with said surface,` consisting in securing .a

thin layer of resilient material such as rubber uniformly and continuously throughout the area of said resilient material on a {lexible but substantially continuous and non-extensible base, forming a permanent printing image on said resilient printing surface substantially coplanar with said surface, and treating said resilient printing surface to cause the portions thereof not covered by said printing image to be ink-repellent.

7. The process of making a planographie printing surface which is resilient in a direction normal to said surface but is substantially non-extensible in directions parallel With said surface, consisting in securing a thin layer of resilientmaterial such as rubber uniformly and continuously throughout the area of said resilient material on a flaxible but substantially continuous and nonextensible base, coating the surface of said resilient material with a light-.sensitive sub'- stance, producing by photography a printing image on said coated resilient surface and then treating said printing surface to cause the portions thereof not covered by said printing image to be ink-repellent.

8. The process of making resilient planographic printing surfaces, consisting in coating the surface of a resilient material such as rubber With a light sensitive coating, producing a photographic image on said sensitized surface by exposing the same to light through a photographic printing element, applying a greasy or etch-resist solution to said surface, developing said image With a developing solution, then applying an ink-repellent solution to said surface, and then Washing said surface.

9. A flexible substantially non-extensible planographic. printing element having Va.

printing surface of resilient material such as rubber provided With a printing image the surface of which is substantially coplanar withsaid printing surface and having a flexible substantially non-yielding uninterrupted smooth backing for said resilient material.

10. A flexible substantially non-extensible printing element comprising a thin facing Asheet of a resilient material such as rubber, a thin flexible metal sheet forming a substantially uninterrupted smooth backing for said resilient facing sheet, and a thin fabric sheet interposed between and intimately attached throughout to said facing sheet and metal sheet.

1l. A planographie printing elementcomprising a base providing a substantially continuous uniform backing, said base being composed of sheet material possessing flexibility but substantially not extensible in directions parallel to the plane of the sheet, a substantially co-extensive sheet of inherently resilientv material, such as rubber, superimposed on said base, said resilient sheet having a direct printing surface provided With an ink-printing image, fixed on and substantially coplanar with said surface, said resilient sheet being substantially uniformly slightly compressible against said base in directions substantially normal to the printing surface to compensate for variations When under pressure, and means for securely attaching said base and resilient sheets uniformly and continuously throughout the areas of their adjacent surfaces whereby to substantially lprevent any displacement of the resilient sheet in directions parallel to the surface thereof.

WILLIAM C. HUEBNER.

Images