US1549187A

US1549187A - Means for correcting printing plates

Info

Publication number: US1549187A
Application number: US605454A
Authority: US
Inventors: Leslie W Claybourn
Original assignee: Individual
Current assignee: Individual
Priority date: 1921-03-19
Filing date: 1922-12-07
Publication date: 1925-08-11
Anticipated expiration: 1942-08-11
Also published as: US1549186A; US1549185A; GB232274A; GB230881A

Description

Aug. 11, 1925. 1,549,187

L. W. CLAYBOURN MEANS FOR CORRECTING PRINTING PLATES Origina} Filed March 1921 2 Sheets-Sheet 1 Aug H, 3925 1,549,187

I... W. CLAYBOURN MEANS FOR CORRECTING PRINTING PLATES O .igi al Filed March 9 9 l 2 Sheets-Sheet 2 fizgfl fig.

\G7 Fz'c28. W 1 29.24. m nuuumllunuumu m n n n u w mu u u u u n u ma P atented Aug. 11, 1925.

LESLIE W. GLAYBOURN, OF MILWAUKEE, WISCONSIN.

MEANS FOR CORRECTING PRINTING- PLATES.

Original application filed March 19, 1921, Serial No. 453,665. Divided and this application filed December 7, 1922. Serial No. 605,454

To all whom it may concern:

Be it known that I. LnsLrn W. CLAYBOURIN.

a citizen of the UnitedStates. residing at.-

Milwaukee. in the county of Milwaukee and State of Wisconsin. have invented certain new and useful Improvements in Means for Correcting Printing Plates, of which the following is a specification.

My present application is a division of an to application heretofore. filed by me in the United States Patent ()flice, March 19. 1.921., as Serial No. 453,665, for method of correcting printing plates and printing plates produced thereby.

I do not herein claim the method of correcting printing plates, or the method of compressing printing plates, or the printing plates produced thereby, herein shown and described. having shown. described and 2c claimed the same in my aforesaid application. Serial No. 453,665.

It is the object of my invention to provide new and improved means for correcting printing plates. whereby to minimize or substantially reduce so-called make-ready on the printing press. My invention is especially applicable to curved printing plates. and I have so shown, described and claimed the same.

It is the object of my invention to provide new and improved means with which to bring all portions of the curved printing surface into the same surface. that is. into the sector of the cylinder which coincideswith the path of the curved printing surface during the printing operation; further. to provide new and improved means whereby to press low portions in the printing surface of a curved printing plate outwardly by pressures in directions substantially radial of the curvature of the printing plate and in manner to maintain the distances, on.the sector of the printing surface thereof, between the'printing lines of said printing surface; and, further, to provide new and improved means with which to locally press the sunken or low printing portions of the curved printing surface. which do not print or which print with too light an impression. outwardly, so that all portions of the curved printing surface will be located on the sector of a cylinder. determined by printing pressures.

Theinvention will be further readily understood from the following description and claims, and from the drawings, in which latter:

Fig. 1 is a cross-sectional view of my improved means, taken in the plane of the line 1-1 of Fig. 2, showing a side elevation of one of my improved tools, and illustrating the manner of its employment.

Fig. 2 is a vertical longitudinal section of the same, taken on the line 22 of Fig. 1.

Fig. 3 is a plan'view of a portion of the backing of a curved printing plate having the locally corrected portion therein.

Fig. 4 is a cross-section of the same, taken on the line H of Fig. 3, in connection with the tool partly broken away, and indicating the printing shell and. the backing of an electrotype printing plate.

Fig. 5 is a cross-sectional view illustrating the imposing of the curved printing plate on a convexly curved saddle.

Fig. 6 is aside elevation of the same. partly broken away, and partly in vertical longitudinal section, taken on the line 6-6 of Fig. 5.

Figs. 7 to 10, inclusive, Figs. 12 to 17, inclusive. Figs. 19 to 21, inclusive. and Figs. L3 to 26. inclusive. represent face views showing the impressing portions of impressing faces of a series of small tools, such as I prefer to employ in local corrections of the curved printing plate, these views having indicating marks in connection therewith to indicate the directions inwhich the impressing faces are curved.

Figs. 11. 18 and 22 represent side eleva tions of the tools, whose impressing faces are shown in Figs. 10, 17 and 21, respectively, and are representative of the tools having thereon the other impressing faces shown.

Fig. 27 is a side elevation of. a bluntpointed small impressing tool.

Fig. 28 is a side elevation of the small tool whose impressing face is illustrated in Fig. 26; and, c

Fig. 29 is an end view of the same, partly in section on the line 29-29 of Fig. 28. i

It has heretofore been a usual practice in making ready for the printing from curved printing plates, to overlay the tympan of the printing press on which the plates are to be printed at those portions at which the printing appears too light in the proofs, or to underlay the curved printing plate at such portions, or to both overlay and underlay at the insufficiently printing portions, with the result that uneven surfaces are obtained both in the tympan and at the bottom of the curved printing plate, such. system making it necessary also to employ a comparatively soft tympan. Other systems have attempted to produce the dilferences between solid and high-light printing effects by locating the high-light printing portions of the plate lower than the solid portions, or nearer the axis of the plate cylinder on which the curved plate is located, this system also producing unevenesses of printing surface.

I produce superior printing-by means of my invention by bringing the printing surface of the printing lines and areas throughout the printing plate equidistant from the finished rear supporting surface of the printing plate, and bringing these two surfaces within the surfaces of two concentric cylinders. determined by printing pressures. I am enabled thereby to bring the backing supporting surface and the printing lines into coaction with surfaces which are equidistant from each other. namely, the surface of the plate-cylinder of the printing press and the surface of a coacting comparatively hard tympan sheet.

I am thereby also enabled to print with a tympan Whose impress surface is unvarying, so that successive printings by different plates or printing elements may be received by the same portions of the tympan, whereby my invention is especially adaptable for so-called wet printing. in which successive printing in different colors are printed upon the same sheet during its single Dassage through the printing press. as well as to all other characters of printing. enhancing the appearance and beauty of the printing. and enabling me to reproduce the appearance of solids. high-lights and intermediate printing effects. in highly contrasted relations in the printing from co-ordinated plates representing different colors, and avoiding the humps and hollows in. the make-ready for one color which are detrimental to the make-ready for another color in the old methods mentioned. and enhancing true registry of the printing lines.

My invention further enables printing to be accomplished with considerably lighter printing pressures and with harder tympans than under such old methods now in general use, and materially increases the numbers of imprints which can baa-obtained from one make-ready of the printing Subject.

The distances and surfaces mentioned are intended to be measured by print-pressures, as they are ordinarilytoo refined for observation by the naked eye.

The printing plate is examplified at 31, and in the present exemplification, (see Fig. 4), comprises a printing shell 32, which may be of usual electro-deposited metal, for instance, copper deposited on the matrix in electrolating, and a backing 33 on which the printing shell is fixedly supported, usually cast into the shell. This backing is usually a composition composed for example of lead, tin and antimony, in the proportion, for example, of ninety pounds of lead and five pounds each of tin and antimony. It is obvious, however, that other backing material may be employed and'that my invention is not limited to printing plates thus formed.

One of the characters of printing plates upon which my present invention is employable, is shown, described and claimed in Letters Patent No. 1,318,967, granted me October 14, 1919, for method of curving printing plates and printing plates curved thereby.

When employing my invention, the printin plate is preferably cast or formed thicker than its ultimate thickness, when finished. in order to permit the same to be shaved at its back or rear surface. whereby to remove the projections in the backing face ofthe curved printing plate caused by employment of my improved devices, although reducing the backing surface is not at all times necessary. The reduction or shaving of the backing of the curved printing plate may be accomplished by any usual means. or by means of the shaving machine shown, described and claimed in Letters Patent No. 1.282013, granted me October 15, 1918, for method of and apparatus for shaving printing plates. it being assumed that such shaving machine having a concave plate support and a rotary shaving element be employed.

Afterthe plate has been cast or formed, a slight shaving is preferably taken off its back so as to reduce the plate to substantial unif'orm thickness throughout its printing surace. 1

If desired. the printing plate may be subjected to compression, prior to the treatment thereof by means of the devices herein shown. described and claimed. such compression being shown, described and claimed in my aforesaid copending application, Serial No. 453,665, by means shown. described and claimed in my 'copending application for patent on improvements in means for compressing printing plates. filed December 7 1922. Serial No. 605,455. which is a division of my aforesaid copending application, Serial No. 453,665.

The curved printing plate has or is likely to have undesirable irregularities in its print ing surface and in thicknesses in different portions of the plate, forming undue high or low places in the printing surface which result in imperfect printing impressions and the practice heretofore of overlaying the tympan or underl y ng the P meals? tor of the cylinder on which the printing surface of the printing plate is formed. The

imposing face impacts theprintingsurface of the printing plate, the blows of the mallet on the imposing block causing recession from the proper printing surface'of any portions thereof backed-by improper support in the backing material.

A proof of the curved printing plate is then taken upon a suitable proof-press hav- ,ing a plate-cylinder, to whichthe curved plate is secured, and. a preferably hard tympan surface to receive the impression of the printing plate upon a sheet of proof paper, which will disclose the low spotsin the printing surface, that is, those portions of the printing surfacebelow the surface of the cylinder, in which the portions of the printing surface properly placed, are 10- cated.

If such proof impression show any portion orportions 'of the printing plate as depressed or inside the surface of the cylinder on which the printing surface of the curved printing plate is properly formed, as by failure to print or printing too light in the proof, the curved printing plate is laid in a trough 41, with its printing surface 42 upon the convexly hardened'face 43 of the trough, which is curved with a curvature forming the sector of a cylinder coincident with the curvature which the finished curved printing plate is toha've, exemplified for instance as a diameter of twelve and a half inches, representingthe diameter of the bearers of a plate-cylinder on which the printing plate is to be mounted. The contact face of this trough for this printing surface, is preferably a hardened contact face, for instanceof hardened'steel, to form an anvil. (See Figs. v1 and 2.) I a That ortion of the back of the printing plate which is opposite the depressed portionof the printing plate, having been previously marked, determined by the show mg in .the proof mentioned, this marked portion is then pressed toward the curved face of the trough. This. is accomplished by means of small finishing tools, exemplified,

for instance, in Figs. 1 and 2, and Figs. 7 to 29, inclusive.

These tools have impact-faces 45 to 62, in-

clusive, for-the back of the plate, which are arranged to locally depress the hollows in the printing surface of the printing plate into eveness with said surface, and comprise for instance protuberances 65 having spaces 66 between them. The areas of the impactfaces of the protuberances vary in size according to the duties they are to perform and the areas they are to cover. They are shownsubstantially full-size in the drawings. The impact faces are formed on the heads of the tools.

The impact-faces are straight on one axis and curved on the axis at right angles thereto upon a curvature corresponding to the curvature of the inner face of the backing of the printing plate being corrected. The indicating niarks67 indicate the directions in which the faces of the tools extend in straight lines, and the indicating marks 68 indicate the directions in which the impact faces thereof are curved. These indicating marks are respectively preferably placed on the straight end or curved side of the tool, as shown in Figs 29, 11, 18, 22 and 28, for conveniencein ready use of the tools.

The protuberances enter the backing ma,- terial of the printing plate, to ress the printing surface thereof outwar ly. The compressed backing material finds partial relief, as shown by the bulges 69, in the spaces between the protuberances, which also prevent spreading of the spaces between printing lines, for maintaining the printing surface in its original registering printing condition. The impact-faces also compress spongy or soft spots in the backing material to impart proper support thereabove to the printingsurface.

It will be noted from the drawings-that printing plates.

Thus the im act-faces may consist of impact-lines, as s own in Figs. 8, 10. 12 to 17 inclusive, 19 to 21 inclusive, and 23, which lines may be solid, as shown in Fig. 8, or, broken, to form protuberances and spaces therebetween, as shown in Figs. 10, 12 to 17 inclusive, 19 to 21 inclusive, and 23. The protuberanoes are of difi'erent shapes. and sizes and the sizes of the spaces between the protuberances also vary, to form more compact or more open areas of impact, as may be desired, as shown by comparing the protuberances and spaces shown in Figs. 7 10, 13, 17, 20, 21, 23 and 24.

The protuberances shown in Figs. 24, 25 and 26 are comparatively small and are subtends over a larger portion of the printing surface and the backing material of said imperfect portion of the printing surface is comparatively hard.

Where the backing is comparatively soft or spongy, I prefer to employ impact-protuberances which are larger in area, and have less space between them, for instance,

as shown in Figs. 14, 15 and 16. Impactprotuberances of still greater impact area may be employed, as shown, for instance, in Figs. 10, 12 and 17, or the impact-protuberances may be smaller in impact area, as shown in Figs. 7 and 9.

Furthermore, the impact areas may be narrow and elongated along the curvature, as shown in Figs. 10, 17 and 21, or the impact areas may be extended along lines parallel with the axis on which the curve is described, as shown in. Figs. 8, 12,.19, 20 and 23. Single straight lines of impact-faces are shown in Figs. 20 and 23, and a single curved line of impact-face is shown, in Fig. 21.

If a single point in the printing. surface is to be raised, for instance a period, or single letter, a tool having a single blunted point, as at 62 in Fig. 27, is employed.

The area of the impact-protuberances may be either square, as shown in Figs. 7, 9, 24, 25 and 26, elongated along the curvature, as shown in Figs, 10, 15 and 17 or elongated parallel with the central axis on which the sector of the cylinder of the printing plate is described, as shown in Figs. 8, 12 and 19. The impact effect upon the backing of the tool exemplified in Figs. 28 and 29, having thereon the impact-face shown in Fig. 26, is shown in Figs. 3 and 4.

Other forms of compressing faces and areas than those shown in the drawings may be employed without departing from the spirit of my invention as embraced within the appended claims.

By employment of may improved device, sunken portions in the curved printing surface may be raised into the proper sector by impact upon the backing face of the curved printing plate, whether those sunken portions extend along lines parallel with the axis on which the sector is described or along the curvature of the. sector, or cover the head thereof in a direction substantially perpendicular to the impact face of the tool, and is arranged to be struck by an impact device. The'impact of the tools upon the printing plate may be caused by suitable hammers, as at 72, preferably small and of little weight, depending on the duties and forces of the impacts which may be desired, for pressing the portion of the plate being corrected locally toward the concave blockor anvil, care being taken to avoid too great a depression in the backing material, the entrance of the impact-faces into the backing being in practice slight.

The provision of the im act face on a manually held tool provide with a shank extending substantially perpendicular to the impact face and arranged to be held by one hand of the operator, enables the impact face of the impact tool being used to be carefully placed on the exact spot in the printing plate it is desired to compress or raise, and enables the tool, after being so placed, to be tapped or to have impacts imparted thereto by a suitable hammer or impact device, manipulated. by the other hand of the operator, for supplying the exact force and direction of force desired for the correction in the printing plate. n

The backing of the printing plate is then again shaved, in manner hereinbefore explained, for again reducing the corrected portion and the balance of the printing plate to proximate uniform thickness at the printing portions, and removing the bulges 69. The shaving thus removed usually represents a thickness of two thousandths of an inch upwards to usually about five thousandths of an inch.

The printing plate thus corrected is again proved, and if any imperfections appear, the plate is again corrected in manner just described, and the backing thereof again shaved, and. these operations repeated in sequence until the proving of the printing plate shows a rinting plate whoseprinting surfaces are t roughout in the same sector,

of a cylinder, and which at its printing portions is of uniform thickness,'in printing effect, so as'to avoidor minimize the necessity of overlaying or underlaying in making ready the-prmting plate, and providing a printing plate which is substantially ready for printing when proper?" placed upon the printing press.

The final shaving to which the curved plate has been subjected, is such as to reduce the curved plate to" such thickness at its printing portions and such curvature at its inner or rear face, that the latter curvature will be coincident with the curvature of'the plate-cylinder on which it is to be fastened .for printing, and the printing surface be concentric therewith, in order that the inner or rear face of the printing plate will make intimate contact thoughout its area with the periphery of the plate-cylinder, and the printing surface lie in a sector of the cylindrical path of the printing surface in the printing operation, and be in printing relation throughout its'printing area with the aware? tympa'n, properly placed, of the printing press.

If any portions of the printing side between printing lines he too shallow, these portions are removed, as by routing in usual manner. I

The curved printing plate may be instancedto be three-sixteenths of an inch thick in its finished state, but the diameters and dimensions given are merely exemplifications and may be altered or changed, or other diameters and dimensions substituted, within the spirit of my invention and the scope of the appended claims.

The impact faces of the correcting tools mentioned are preferably ofgsizescmaterially less than the sizes of the curved printing plates being corrected, so as to act locally upon those portions only of the curved printing plate which show low or are within the projection of the sector of the cylinder of the printing surface of the curved printing plate, and to bring these low portions outwardly into'the proper surface of the properly placed portion of the printing surface of the curved printing plate.

, By employment of my improved devices,

i a printing plate is obtained having a printing surface, the printing lines of which are located in the surface of the same sector of a cylinder, as determined by printing pressures. When using curved printing plates corrected by my improveddevices, a comparatively hard tympan surface is employed, which is also in a given surface, either plane or cylindrical, depending on whether a fiat tympan or a curved tympan, so that the printing contact is what may be termed a kiss contact between the paper and ink for transferring the pigments of ink to the paper, and avoiding all rubbin contact between the paper and the ink Whic is incident to causing the paper being printed to be received in depressions, or causing the paper being printed to be bent over bulges, in the'faces of make-readies as now generally employed.

Having thus fully described my mvention, what I claim as new, and desire to secure by Letters Patent, is:

1. In means for correcting a curved print- I ing plate, the combination of a concave anvil havin an impact-face arranged on the sector 0 a cylinder and of greater area than the area of the curved printing plate, said impact-face arranged for coaction with the curved printin surface of said curved printing plate, an a correcting tool comprising a head having a convexly curved impact-face of an area substantially less than the area of said curved printing plate, for coaction at any one time with a-relatively small portion of the curved backin face of said curved printing plate, sai lastnamed impact-face provided with depressions forming projections and depressions in said last-named curved impact-face, said impact-faces arranged on sectors of cylinders which are concentric when said secondnamed impact-face is being used on said backing face of said curved printing plate, with said curved printing plate between said concentric sectors, said correcting tool further comprising a combined holding and impact-stem extending from said head perpendicular to said impact-face thereon, whereby the blows of a hammer on the end of said stem are transmitted to, said second-' named impact-face in lines perpendicular thereto, and arranged whereby said secondnamed impact-face is placeable on the desired portion of the backing of said printing plate to rest thereon prior to impact by said hammer on said stem.

2. In means for correcting a curved printing plate, the combination of a concave anvil having an impact-face arranged on the sector of a cylinder and of greater area than the area of the curved printingplate,

said impact-face arranged for coaction with the curved printing surface of said curved printing plate, and a correcting tool comprising a head having a convexl curved impact-face of an area substantially less than the area of said curved printing plate, for coaction at any one time with a relatively small portion of the curved backing face of said curved printing plate, said lastnamed impact-face provided with depressions forming projections and depressions in said last-named curved. impact-face, said impact faces arranged on sectors of cylinders which are concentric when said secondnamed'impact-face is being used on said backing face of said curved printing plate with said curved printing plate between said concentric sectors, said correctingtool further comprising a combined holding and impact-stem extending from said head perpendicular to said impact-face thereon, whereby the blows of a hammer on the end of said stem are transmitted to said secondnamed impact-face in lines perpendicular thereto, and arranged whereby said secondnamed impact-face is placeable on the desired. portion'of the bac ing of said printing plate to rest thereon prior to impact by said hammer on said stem, said impact-face of said head curved on one of its axes and straight on its axes at right angles thereto, and said head provided with indicatin marks to denote the relatively curved an 'strai ht character of said axes.

3. 11 means for correcting a curved print ing plate, the combination of a concave anvil having an impact-face arranged on the sector of a cylinder and of greater area than the area of the curved printing plate, said impact-face arranged for coaction with the curved printing surface of said curved print-- ing plate, and a correcting tool comprising a head having a convexly curved impactlace of an area substantially less than the area of said curved printing plate, for coaction at any one time with a relatively small portion of the curved backing face of said curved printing plate, said last-named impact-face provided with depressions forming projections and depressions in said lastnamed curved impact-face, said impact-faces arranged on sectors of cylinders which are concentric when said second-named impactface is being used on said backing face of said curved printing plate with said curved printing plate between said concentric sectors, said correcting tool further comprising a combinedholding and impact-stem extending from said head perpendicular to said impact-face thereon, whereby the blows of a hammer on the end of said stem are transmitted to said second-named impactthereon prior to impact by said hammer on 7 said stem, said depressions arranged to receive metal of the backing of said curved printing plate displaced by said projections, and said projections substantially confinin the metal acted on.by said second-name impact-face within the area of said impactfaceto retard local spreading in said curved printing plate.

In testimony whereof, I have hereunto signed my name in the presence of two subscribing witnesses.

LESLIE W. CLAYBOUR-N.

Witnesses JOSEPH LEWKUHL, DELMA 'WEnNsINo.