US979111A - Printing-surface and method of producing the same. - Google Patents

Description

B. F. UPHAM. PRINTING SURFACE AND METHOD OF PRODUCING THE SAME. APPLICATION IILED JAN. 22, 1901.

979, 1 1 1 Patented Dec. 20, 1910.

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His flttarllqy CORPORATION OF NEW JERSEY.

CBURT F. UPHAM, 013 BOSTON, IWIASSACHUSET COMPANY, OF JERSEY CITY, NEW JER- TS, ASSIGNOR TO C. B. COTTRELL AND SONS SEY, AND WESTERLY, RHODE ISLAND, A

PRINTING-SURFACE AND METHOD OF PRODUCING THE SAME.

Specification of Letters Patent. 7 Patented Dec. 20, 1910.

Application filed January 22, 19D1. Serial No. 44,308.

To all whom it may concern:

Be it known that I, BURT F. UPHAM, a citizen of the United States, and residing at the city of Boston, in the county of Suffolk and State of Massachusetts, have-invented certain new and useful Improvements in Printing-Surfaces and Methods of Producing the Same, of which the following is a full, clear, and exact description.

In relief'printing, it is customary to vary the pressure upon different sections of the printing surface in accordance with the depths of the shades. In other words, the lighter the printing shade, the lighter the pressure is made; and the blacker the shade, the heavier the pressure. This has usually been done by means of overlays and underlays, the former consisting in adding thin cuttings of paper to the impression surface at the points where the increased pressure is desired; and the latter consisting in intro.- ducing similar cuttings beneath the electrotyped printing surface.

My invention has for its object the permanent alteration of the printing surface itself, through the elevation of its heavier shades and depression of its lighter tints, in order that itmay instant it is placed upon the press, and so all overlays or underlays made entirely unnecessary therefor; and, further, to the end that all electro types or other automatic duplications of the original surface may be equally ready for instant use.

lVhile there are many ways in which this object may be'accolnplished, I disclose but a single method, that in which the essential features consist in producing the required permanent profiling of the printing surface by pressure.

Referring to the drawings forming part of this specification, Figure l is a. face view of a simple printing surface or of a proof therefrom. Figs. 2 and 3 are plan views of two properly cut pieces of paper used in the construction of a reverse overlay employed in my process. Figs. 4, 5 and 6 are other pieces of properly cut paper for other sections of said reverse overlay. .Fig. 7 is a crosssection of said reverse overlay laid upon the printing surface. Fig. 8 is a side sectional elevation of the same introduced between the members of a hydraulic or other be ready for perfect work the.

press. Fig. 9 is a cross-section of a finished printing surface made in accordance with my process.

In carrying my preferred process into effect, I form a relief engraving upon a thin sheet or plate of copper or other metal; the same being done either by hand, by electroplating or electrotypi-ng from a woodcut, or byany of the well known photochemical processes. The thickness which I find gives the best results is thirty-one thousandths of an inch for plates of hard copper. Having taken a number of proofs from the engraving, I proceed to make a reverse overlay, building up the same from several of these proofs; the number being five to six thicknesses of thin paper for fine work, and two to three thicknesses of heavier paper for ordinary newspaper work. In making this reverse overlay, I cut out all the blackest shades from the proofs, and more or less of the next darkest shades, the number of layers of paper. permitted to remain being in inverse proportion to the depth of the shade, while the lightest shades are not cut out at all. The engraved plate is then laid upon a comparatively soft 1naterial, preferably the lead which is to constitute the backing therefor, and the reverse overlay placed in register upon the face of the said plate. The whole is then subjected to a heavy pressure between the perfectly flat and parallel faces of a suitable press. As a result, the thicker portions of the reverse overlay are made to forcibly depress the engraved plate and the lead backing beneath, giving to the engraving a surface whieh has its darker shades elevated above the lighter sections in proportion to their relative differences in shade, at the same time inseparably incorporating the plate and lead backing. The completed engraving can now be employed upon the printing press, or electrotypes or stereotypes can be made therefrom and these printed from, without the delay of overlays or underlays. I

I show in Fig. l of the drawings an engraved plate 1 of a block letter A. in solid black upon a moderately dark background, surrounded by a lighter border. Having pulled several proofs from this engraving, I proceed to build up the reverse overlay.

In doing this, I cut from certain of the proofs,preferably three,all the heavy black, and paste them in register one upon another on an uncut proof. Fig. 6 shows the one coming immediately upon the uncut proof; Fig. 5, the next, and Fig. 4, the last. As shown, the part cut away is larger than the letter A in each case, especially so in the proofs farthest removed from the uncut proof. By this means, the edges of the letter A as cut away in the three proofs do not coincide and produce an abrupt descent, but taper the same off more gradually. In the same manner, I paste the cut away proofs shown in Figs. 2 and 3, on the growing overlay; the square cut out in each being larger than the dark back-ground, the outermost one more than the other. The object of thus having the cut-out section larger than the dark shade, and thereby bringing the edges over the lighter part of the proof, will be set forth hereinafter. The reverse overlay as thus built up is indicated in an exaggerated form at 5 in Fig. 7, and also Fig. 8.

The reverse overlay 5 being properly laid upon the engraved plate 1, and the latter placed 011 the lead backing 10, the whole is put between the accurately parallel and true members 15, 16 of the hydraulic or other suitable press. First, however, a sheet 17 of fiber-board or thin metal is introduced between the reverse overlay. and the engraved plate, for the purpose to be explained below. \Vhen the press is put in operation, the lead backing will flow sufiiciently to permit the reverse overlay to force downward all the lighter sections of the engraved plate, and hence leave the blacker sections slightly elevated; as indicated in Fig. 9 where 12 represents the ele vated darkest section; 11, the medium, and 13 the lightest sections. The press may now be opened and the engraving removed therefrom complete and in perfect readiness for use. It is, of course, necessary to insert a sheet of paper or card freshly coated with paste or cement bet-ween the plate and backing before placing in the hydraulic press to make the said parts solidly adhere together.

The object in tapering off the cut edges of the overlay, and introducing the thin sheet 17 is to prevent any sharp bends in the engraved plate and consequent blank lines in the prints, or linesof but partially printed space. I have discovered that if the cut away sections of the overlay coincides exactly with the boundaries of the blackest parts of the engraving, there would be a similar failure to print the lighter parts immediately adjoining such boundaries. Consequently. I cut out the overlay paper to bring the same outside of the said boundaries, and locate the edges of the cuts just within the lighter parts. This wholly ovcrcomes the difficulty complained of. The explanation of the said difficulty is seen in the probable fact of the elevated dark sections of the engraving supporting the paper being printed sothat it does not sufiiciently press upon the nearest parts of the less elevated plate; while, by elevating such parts also to a gradually lessening degree, the pressure is reduced more uniformly.

In adapting wood engravings to my process, Ifirst produce an electrotype and back the same with lead or other comparatively soft composition in the usual manner. A reverse overlay is then made as above described, and pressed into the same to secure the desired uneven printing surface.

In the use of printing surfaces thus pre pared, the printer is wholly relieved of the bother and delay of cutting overlays or other systems of make-ready therefor; it being my purpose to have this proper profiling of the engraving done by the engravers or electrotypers before, the original delivery thereof. This both saves the time of the printer, and in addition causes the work to be done by men who are thorough experts in the art of producing the best possible results with half-tones and other difficult forms of engravings. Secondly, in the case of engravings which are to be frequently used, there is no repetition in the work of making and fitting overlays, but the engraving is always ready for immediate use whenever desired.- So also, in large establishments employing several presses en gaged upon duplicate electrotypes, it is necessary to cut an equal number of similar overlays, since the electrotypes are all exact duplicates of the original properly profiled surface, and turn out similarly perfect work without further trouble or attention.

Although I prefer pressure as the means for profiling the printing surfaces, I do not restrict myself thereto as I have other ways of accomplishing this part of the process, which I do not wish at this time to disclose. Neither do I restrict myself to the reverse overlay as the means for enabling pressure to .thus prepare the surface.

On account of the comparative rigidity and inflexibility of the copper plates ordinarily used for the engraving of half-tones, I find it impossible to properly profile the same; the only suitable results being accomplished with-much thinner plates, those not exceeding thirty-one thousandths of an inch.

What I claim as my invention and for which I desire Letters Patent is as follows, to wit 1. The hereindescribed process of produc ing printing surfaces which consists in first forming a relief printing surface in a thin metallic plate, supporting the same upon a yielding backing, and finally forcing into then pressing the same directly into the face of a printing plate and thereby producing permanent impressions in the face of the plate.

13. The herein described process of producing make ready printing plates Which consists in first producing a reverse overlay and then pressing the same directly into the face of an electrotype printing plate and thereby producing permanent impressions in the face of the plate.

14. A make ready printing plate consisting of a thin metal shell into which the make ready has been directly pressed and a suitable backing for said shell separately secured thereto simultaneously with the pressing operation.

15. A make ready printing plate consisting of a thin metal shell in which the make ready has been directly formed by pressure, and a lead backing for said shell separately secured thereto simultaneously with the pressing operation.

16. A make ready printing plate consisting of a thin metal shell and a softer BURT F. UPHAM.

"Witnesses:

FREDERIO S. LYNCH, A. B. UPHABI.

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